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Sample records for aerogenes enterobacter cloacae

  1. Enterobacter aerogenes and Enterobacter cloacae; versatile bacterial pathogens confronting antibiotic treatment

    PubMed Central

    Davin-Regli, Anne; Pagès, Jean-Marie

    2015-01-01

    Enterobacter aerogenes and E. cloacae have been reported as important opportunistic and multiresistant bacterial pathogens for humans during the last three decades in hospital wards. These Gram-negative bacteria have been largely described during several outbreaks of hospital-acquired infections in Europe and particularly in France. The dissemination of Enterobacter sp. is associated with the presence of redundant regulatory cascades that efficiently control the membrane permeability ensuring the bacterial protection and the expression of detoxifying enzymes involved in antibiotic degradation/inactivation. In addition, these bacterial species are able to acquire numerous genetic mobile elements that strongly contribute to antibiotic resistance. Moreover, this particular fitness help them to colonize several environments and hosts and rapidly and efficiently adapt their metabolism and physiology to external conditions and environmental stresses. Enterobacter is a versatile bacterium able to promptly respond to the antibiotic treatment in the colonized patient. The balance of the prevalence, E. aerogenes versus E. cloacae, in the reported hospital infections during the last period, questions about the horizontal transmission of mobile elements containing antibiotic resistance genes, e.g., the efficacy of the exchange of resistance genes Klebsiella pneumoniae to Enterobacter sp. It is also important to mention the possible role of antibiotic use in the treatment of bacterial infectious diseases in this E. aerogenes/E. cloacae evolution. PMID:26042091

  2. Draft Genome Assemblies of Enterobacter aerogenes CDC 6003-71, Enterobacter cloacae CDC 442-68, and Pantoea agglomerans UA 0804-01.

    PubMed

    Minogue, T D; Daligault, H E; Davenport, K W; Bishop-Lilly, K A; Bruce, D C; Chain, P S; Coyne, S R; Chertkov, O; Freitas, T; Frey, K G; Jaissle, J; Koroleva, G I; Ladner, J T; Palacios, G F; Redden, C L; Xu, Y; Johnson, S L

    2014-01-01

    The Enterobacteriaceae are environmental and enteric microbes. We sequenced the genomes of two Enterobacter reference strains, E. aerogenes CDC 6003-71 and E. cloacae CDC 442-68, as well as one near neighbor used as an exclusionary reference for diagnostics, Pantoea agglomerans CDC UA0804-01. The genome sizes range from 4.72 to 5.55 Mbp and have G+C contents from 54.6 to 55.1%. PMID:25342683

  3. Infectious discitis caused by Enterobacter cloacae.

    PubMed Central

    Solans, R; Simeon, P; Cuenca, R; Fonollosa, V; Bago, J; Vilardell, M

    1992-01-01

    The case is reported of a patient who developed a vertebral osteomyelitis caused by Enterobacter cloacae. The organism was isolated in cultures of blood and vertebral puncture biopsy samples. The patient was satisfactorily treated with trimethroprim and sulphamethoxazole. Enterobacter cloacae, a Gram negative organism, has been confirmed as the cause of bacteremia in patients with burns, urinary infections, in adults with pneumonia, and in children with joint infections. Spondylodiscitis caused by Enterobacter cloacae has not previously been described. Images PMID:1632668

  4. Genomic Diversity within the Enterobacter cloacae Complex

    PubMed Central

    Paauw, Armand; Caspers, Martien P. M.; Schuren, Frank H. J.; Leverstein-van Hall, Maurine A.; Delétoile, Alexis; Montijn, Roy C.; Verhoef, Jan; Fluit, Ad C.

    2008-01-01

    Background Isolates of the Enterobacter cloacae complex have been increasingly isolated as nosocomial pathogens, but phenotypic identification of the E. cloacae complex is unreliable and irreproducible. Identification of species based on currently available genotyping tools is already superior to phenotypic identification, but the taxonomy of isolates belonging to this complex is cumbersome. Methodology/Principal Findings This study shows that multilocus sequence analysis and comparative genomic hybridization based on a mixed genome array is a powerful method for studying species assignment within the E. cloacae complex. The E. cloacae complex is shown to be evolutionarily divided into two clades that are genetically distinct from each other. The younger first clade is genetically more homogenous, contains the Enterobacter hormaechei species and is the most frequently cultured Enterobacter species in hospitals. The second and older clade consists of several (sub)species that are genetically more heterogonous. Genetic markers were identified that could discriminate between the two clades and cluster 1. Conclusions/Significance Based on genomic differences it is concluded that some previously defined (clonal and heterogenic) (sub)species of the E. cloacae complex have to be redefined because of disagreements with known or proposed nomenclature. However, further improved identification of the redefined species will be possible based on novel markers presented here. PMID:18716657

  5. Transmission of Enterobacter aerogenes septicemia in healthcare workers.

    PubMed

    Jha, Piyush; Kim, Choon-Mee; Kim, Dong-Min; Chung, Jong-Hoon; Yoon, Na-Ra; Jha, Babita; Kim, Seok Won; Jang, Sook Jin; Ahn, Young-Joon; Chung, Jae Keun; Jeon, Doo Young

    2016-01-01

    Enterobacter aerogenes is recognized as an important bacterial pathogen in hospital-acquired infections. This report describes two unusual cases of septicemia caused by E. aerogenes in immunocompetent healthcare workers. E. aerogenes was isolated from blood cultures of the two patients experiencing septicemia. The clinical isolates were initially identified as E. aerogenes using a VITEK II automated system and 16S rRNA sequence analysis, and; both isolates involved in the outbreak shared a common pulse-field gel electrophoresis pattern. The similarities between the two cases included the simultaneous development of gastroenteritis symptoms, severe sepsis and thrombocytopenia after taking intravenous injections of ketorolac tromethamine. A common source of normal saline, a 100 mL bottle, was used for diluting the analgesic in both cases. In addition to the general population, healthcare workers, especially those who are also intravenous drug abusers, should be considered subjects that could cause a transmission of Enterobacter infection. PMID:27610316

  6. Draft genome sequence of Enterobacter cloacae subsp. cloacae strain 08XA1, a fecal bacterium of giant pandas.

    PubMed

    Yan, Yue; Zhao, Chuan-Wu; Zhang, Yi-Zheng; Zhang, Zhi-He; Pan, Guang-Lin; Liu, Wen-Wang; Ma, Qing-Yi; Hou, Rong; Tan, Xue-Mei

    2012-12-01

    Enterobacter cloacae, a common pathogenic bacterium, is a Gram-negative bacillus. We analyzed the draft genome of Enterobacter cloacae subsp. cloacae strain 08XA1 from the feces of a giant panda in China. Genes encoding a β-lactamase and efflux pumps, as well as other factors, have been found in the genome. PMID:23209197

  7. Detection of amp C in Enterobacter cloacae in China.

    PubMed

    Zhang, Y L; Li, J T; Zhao, M W

    2001-10-01

    PCR amplification of 55 strains of Enterobacter cloacae indicated 51 of them had amp C structural gene verified by DNA sequence and Southern blotting. All PCR products were cleaved into 666- and 328-bp fragments by Kpn1 restriction enzyme. Imipenem was the most potent inducer for mRNA expression of amp C gene and beta-lactamase activity. The beta-Lactamase inhibitor R0481220 strongly inhibited Amp C beta-lactamases; 96.4% (53/55) of Enterobacter cloacae producing Amp C enzyme were susceptible to cefepime. PMID:11691570

  8. Enterobacter cloacae inhibits human norovirus infectivity in gnotobiotic pigs

    PubMed Central

    Lei, Shaohua; Samuel, Helen; Twitchell, Erica; Bui, Tammy; Ramesh, Ashwin; Wen, Ke; Weiss, Mariah; Li, Guohua; Yang, Xingdong; Jiang, Xi; Yuan, Lijuan

    2016-01-01

    Human noroviruses (HuNoVs) are the leading cause of epidemic gastroenteritis worldwide. Study of HuNoV biology has been hampered by the lack of an efficient cell culture system. Recently, enteric commensal bacteria Enterobacter cloacae has been recognized as a helper in HuNoV infection of B cells in vitro. To test the influences of E. cloacae on HuNoV infectivity and to determine whether HuNoV infects B cells in vivo, we colonized gnotobiotic pigs with E. cloacae and inoculated pigs with 2.74 × 104 genome copies of HuNoV. Compared to control pigs, reduced HuNoV shedding was observed in E. cloacae colonized pigs, characterized by significantly shorter duration of shedding in post-inoculation day 10 subgroup and lower cumulative shedding and peak shedding in individual pigs. Colonization of E. cloacae also reduced HuNoV titers in intestinal tissues and in blood. In both control and E. cloacae colonized pigs, HuNoV infection of enterocytes was confirmed, however infection of B cells was not observed in ileum, and the entire lamina propria in sections of duodenum, jejunum, and ileum were HuNoV-negative. In summary, E. cloacae inhibited HuNoV infectivity, and B cells were not a target cell type for HuNoV in gnotobiotic pigs, with or without E. cloacae colonization. PMID:27113278

  9. Biological Conversion of Glycerol to Ethanol by Enterobacter aerogenes

    NASA Astrophysics Data System (ADS)

    Nwachukwu, Raymond E. S.

    In a search to turn the economically and environmentally non-valuable "waste" streams of biodiesel production into a profitable byproduct, a mutant strain of Enterobacter aerogenes ATCC 13048 was developed by six-tube subculturing technique. This technique is based on the principle of adaptive evolution, and involved subculturing the bacterium in a tryptic soy broth without dextrose (TSB) containing specific glycerol and ethanol concentration for six consecutive times. Then, the six consecutive subculturing was repeated in a fresh TSB of higher glycerol and ethanol concentrations. A new mutant strain, E. aerogenes S012, which could withstand a combination of 200 g/l glycerol and 30 g/l ethanol concentrations, was developed. The wild and mutant strains were used for the fermentation of pure (P-) and recovered (R-) glycerol. Taguchi and full factorial methods of design of experiments were used to screen and optimize the important process factors that influence the microbial production of ethanol. A statistically sound regression model was used to establish the mathematical relationship between the process variables and ethanol production. Temperature of 38°C, agitation speed of 200 rpm, pH of 6.3-6.6, and microaerobic condition were the optimum process conditions. Different pretreatment methods to recover glycerol from the crude glycerol and the subsequent fermentation method showed that direct acidification using 85% H3PO4 was the best. The R-glycerol contained 51% pure glycerol and 21% methanol. The wild strain, E. aerogenes ATCC 13048, produced only 12 g/l and 12.8 g/l ethanol from 20 g/l P- and R-glycerol respectively, and could not utilize higher glycerol concentrations. The mutant, E. aerogenes S012, produced ethanol amount and yield of 43 g/l and 1.12 mol/mol-glycerol from P-glycerol, respectively within 96 h. It also produced ethanol amount and yield of 26.8 g/l and 1.07 mol/mol-glycerol, respectively, from R-glycerol within the same duration. In a

  10. PYRUVATE DEHYDROGENASE ACTIVITY IS IMPORTANT FOR COLONIZATION OF SEEDS AND ROOTS BY ENTEROBACTER CLOACAE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enterobacter cloacae shows promise for suppression of damping-off of cucumber and other crops caused by Pythium ultimum. Enterobacter cloacae M43 is a transposon mutant of E. cloacae 501R3 that was significantly impaired in colonization of seeds and roots of diverse crop plants. Strain M43 did not...

  11. Bioconversion of glycerol to ethanol by a mutant Enterobacter aerogenes

    PubMed Central

    2012-01-01

    The main objective of this research is to develop, by adaptive evolution, mutant strains of Enterobacter aerogenes ATCC 13048 that are capable of withstanding high glycerol concentration as well as resisting ethanol-inhibition. The mutant will be used for high ethanol fermentation from glycerol feedstock. Ethanol production from pure (P-) and recovered (R-) glycerol using the stock was evaluated. A six-tube-subculture-generations method was used for developing the mutant. This involved subculturing the organism six consecutive times in tubes containing the same glycerol and ethanol concentrations at the same culture conditions. Then, the glycerol and/or ethanol concentration was increased and the six subculture generations were repeated. A strain capable of growing in 200 g/L glycerol and 30 g/L ethanol was obtained. The ability of this mutant, vis-à-vis the original strain, in utilizing glycerol in a high glycerol containing medium, with the concomitant ethanol yield, was assessed. Tryptic soy broth without dextrose (TSB) was used as the fermentation medium. Fermentation products were analyzed using HPLC. In a 20 g/L glycerol TSB, E. aerogenes ATCC 13048 converted 18.5 g/L P-glycerol and 17.8 g/L R-glycerol into 12 and 12.8 g/L ethanol, respectively. In a 50 g/L P-glycerol TSB, it utilized only 15.6 g/L glycerol; but the new strain used up 39 g/L, yielding 20 g/L ethanol after 120 h, an equivalence of 1.02 mol ethanol/mol-glycerol. This is the highest ethanol yield reported from glycerol bioconversion. The result of this P-glycerol fermentation can be duplicated using the R-glycerol from biodiesel production. PMID:22455837

  12. Enterobacter cloacae is an endophytic symbiont of corn.

    PubMed

    Hinton, D M; Bacon, C W

    1995-01-01

    The bacterium Enterobacter cloacae is presently used for biocontrol of postharvest diseases of fruits and vegetables and as a preplant seed treatment for suppression of damping-off. This bacterium has apparent affinities for several grass species, but it is not considered to be an endophyte. While screening corn for fungi and bacteria with potential for biocontrol of various corn diseases, the surface-sterilized kernels of one unknown Italian corn cultivar produced fungus-free corn seedlings with roots endophytically infected by E. cloacae. This paper describes the microscopic nature of E. cloacae RRC 101 with corn, and the in vitro control of Fusarium moniliforme and other fungi with this bacterium. Light and electron microscopy determined that this isolate of E. cloacae was biologically associated with corn seedling roots, where it was distributed intercellularly within the cortex and stele. This is a first report of a strain of this bacterium as an endophytic symbiont of roots. Following a topical application of E. cloacae to kernels, and upon germination this bacterium readily infected roots of two other corn cultivars. The bacterium was observed within the endosperm of germinating corn seedling, but germination was not affected. Further, the bacterium was isolated from leaves and stems of 3- to 6-week-old seedlings indicating that the above ground portions of corn were also colonized. There was no evidence of damage to cells of the root during a three to four week observation period. This bacterium was antagonistic to several isolates of the corn pathogen Fusarium moniliforme, and to two other species of fungi, all of which produce mycotoxins on corn. PMID:7659140

  13. Antibiotic failure mediated by a resistant subpopulation in Enterobacter cloacae.

    PubMed

    Band, Victor I; Crispell, Emily K; Napier, Brooke A; Herrera, Carmen M; Tharp, Greg K; Vavikolanu, Kranthi; Pohl, Jan; Read, Timothy D; Bosinger, Steven E; Trent, M Stephen; Burd, Eileen M; Weiss, David S

    2016-01-01

    Antibiotic resistance is a major public health threat, further complicated by unexplained treatment failures caused by bacteria that appear antibiotic susceptible. We describe an Enterobacter cloacae isolate harbouring a minor subpopulation that is highly resistant to the last-line antibiotic colistin. This subpopulation was distinct from persisters, became predominant in colistin, returned to baseline after colistin removal and was dependent on the histidine kinase PhoQ. During murine infection, but in the absence of colistin, innate immune defences led to an increased frequency of the resistant subpopulation, leading to inefficacy of subsequent colistin therapy. An isolate with a lower-frequency colistin-resistant subpopulation similarly caused treatment failure but was misclassified as susceptible by current diagnostics once cultured outside the host. These data demonstrate the ability of low-frequency bacterial subpopulations to contribute to clinically relevant antibiotic resistance, elucidating an enigmatic cause of antibiotic treatment failure and highlighting the critical need for more sensitive diagnostics. PMID:27572838

  14. Eight-Year Surveillance of Antimicrobial Resistance among Enterobacter Cloacae Isolated in the First Bethune Hospital

    NASA Astrophysics Data System (ADS)

    Zhou, Qi; Zhang, Man; Wang, Ailin; Xu, Jiancheng; Yuan, Ye

    This study was to investigate the antimicrobial resistance of Enterobacter cloacae isolated in 8 consecutive years in the First Bethune Hospital. Disk diffusion test was used to study the antimicrobial resistance. The data were analyzed by WHONET 5 software according to Clinical and Laboratory Standards Institute (CLSI). Most of 683 strains of Enterobacter cloacae were collected from sputum 410 (60.0%), secretions and pus 105 (15.4%), urine 69 (10.1%) during the past 8 years. No Enterobacter cloacae was resistant to imipenem and meropenem in the First Bethune Hospital. The antimicrobial resistance of Enterobacter cloacae had increased in recent 8 years. The change of the antimicrobial resistance should be investigated in order to direct rational drug usage in the clinic and prevent bacterial strain of drug resistance from b eing transmitted.

  15. Antibacterial activity of cefoperazone alone and in combination against cephalosporinase-producing Enterobacter cloacae.

    PubMed Central

    Minami, S; Matsubara, N; Yotsuji, A; Watanabe, Y; Yasuda, T; Saikawa, I; Mitsuhashi, S

    1983-01-01

    The activity of cefoperazone against a strain with an inducible cephalosporinase and a mutant that produces the enzyme constitutively indicates that the low inducer activity of this antibiotic plays an important role in its activity against Enterobacter cloacae. PMID:6605112

  16. Isolation and characterization of a bacteriophage phiEap-2 infecting multidrug resistant Enterobacter aerogenes

    PubMed Central

    Li, Erna; Wei, Xiao; Ma, Yanyan; Yin, Zhe; Li, Huan; Lin, Weishi; Wang, Xuesong; Li, Chao; Shen, Zhiqiang; Zhao, Ruixiang; Yang, Huiying; Jiang, Aimin; Yang, Wenhui; Yuan, Jing; Zhao, Xiangna

    2016-01-01

    Enterobacter aerogenes (Enterobacteriaceae) is an important opportunistic pathogen that causes hospital-acquired pneumonia, bacteremia, and urinary tract infections. Recently, multidrug-resistant E. aerogenes have been a public health problem. To develop an effective antimicrobial agent, bacteriophage phiEap-2 was isolated from sewage and its genome was sequenced because of its ability to lyse the multidrug-resistant clinical E. aerogenes strain 3-SP. Morphological observations suggested that the phage belongs to the Siphoviridae family. Comparative genome analysis revealed that phage phiEap-2 is related to the Salmonella phage FSL SP-031 (KC139518). All of the structural gene products (except capsid protein) encoded by phiEap-2 had orthologous gene products in FSL SP-031 and Serratia phage Eta (KC460990). Here, we report the complete genome sequence of phiEap-2 and major findings from the genomic analysis. Knowledge of this phage might be helpful for developing therapeutic strategies against E. aerogenes. PMID:27320081

  17. Isolation and characterization of a bacteriophage phiEap-2 infecting multidrug resistant Enterobacter aerogenes.

    PubMed

    Li, Erna; Wei, Xiao; Ma, Yanyan; Yin, Zhe; Li, Huan; Lin, Weishi; Wang, Xuesong; Li, Chao; Shen, Zhiqiang; Zhao, Ruixiang; Yang, Huiying; Jiang, Aimin; Yang, Wenhui; Yuan, Jing; Zhao, Xiangna

    2016-01-01

    Enterobacter aerogenes (Enterobacteriaceae) is an important opportunistic pathogen that causes hospital-acquired pneumonia, bacteremia, and urinary tract infections. Recently, multidrug-resistant E. aerogenes have been a public health problem. To develop an effective antimicrobial agent, bacteriophage phiEap-2 was isolated from sewage and its genome was sequenced because of its ability to lyse the multidrug-resistant clinical E. aerogenes strain 3-SP. Morphological observations suggested that the phage belongs to the Siphoviridae family. Comparative genome analysis revealed that phage phiEap-2 is related to the Salmonella phage FSL SP-031 (KC139518). All of the structural gene products (except capsid protein) encoded by phiEap-2 had orthologous gene products in FSL SP-031 and Serratia phage Eta (KC460990). Here, we report the complete genome sequence of phiEap-2 and major findings from the genomic analysis. Knowledge of this phage might be helpful for developing therapeutic strategies against E. aerogenes. PMID:27320081

  18. Complete Genome Sequence of Enterobacter cloacae B2-DHA, a Chromium-Resistant Bacterium

    PubMed Central

    Rahman, Aminur; Nahar, Noor; Olsson, Björn

    2016-01-01

    Previously, we reported a chromium-resistant bacterium, Enterobacter cloacae B2-DHA, isolated from the landfills of tannery industries in Bangladesh. Here, we investigated its genetic composition using massively parallel sequencing and comparative analysis with other known Enterobacter genomes. Assembly of the sequencing reads revealed a genome of ~4.21 Mb in size. PMID:27257201

  19. Complete Genome Sequence of Enterobacter cloacae B2-DHA, a Chromium-Resistant Bacterium.

    PubMed

    Rahman, Aminur; Nahar, Noor; Olsson, Björn; Mandal, Abul

    2016-01-01

    Previously, we reported a chromium-resistant bacterium, Enterobacter cloacae B2-DHA, isolated from the landfills of tannery industries in Bangladesh. Here, we investigated its genetic composition using massively parallel sequencing and comparative analysis with other known Enterobacter genomes. Assembly of the sequencing reads revealed a genome of ~4.21 Mb in size. PMID:27257201

  20. Enterobacter aerogenes Needle Stick Leads to Improved Biological Management System

    SciTech Connect

    Johanson, Richard E.

    2004-08-01

    A laboratory worker who received a needle stick from a contaminated needle while working with a culture containing Enterobactor aerogenes developed a laboratory acquired infection. Although this organism has been shown to cause community and nosocomial infections, there have been no documented cases of a laboratory acquired infections. Lessons learned from the event led to corrective actions which included modification of lab procedures, development of a biological inventory tracking and risk identification system and the establishment of an effective biological safety program.

  1. Complete genome sequence of Enterobacter cloacae GGT036: a furfural tolerant soil bacterium.

    PubMed

    Gong, Gyeongtaek; Um, Youngsoon; Park, Tai Hyun; Woo, Han Min

    2015-01-10

    Enterobacter cloacae is a facultative anaerobic bacterium to be an important cause of nosocomial infection. However, the isolated E. cloacae GGT036 showed higher furfural-tolerant cellular growth, compared to industrial relevant strains such as Escherichia coli and Corynebacterium glutamicum. Here, we report the complete genome sequence of E. cloacae GGT036 isolated from Mt. Gwanak, Seoul, Republic of Korea. The genomic DNA sequence of E. cloacae GGT036 will provide valuable genetic resources for engineering of industrially relevant strains being tolerant to cellular inhibitors present in lignocellulosic hydrolysates. PMID:25444880

  2. MUTATION IN A DEGS HOMOLOGUE IN ENTEROBACTER CLOACAE RESULTS IN DECREASED SEEDLING AND ROOT COLONIZATION BY THIS BACTERIUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enterobacter cloacae 501R3 shows promise as a biological control agent for damping-off of cucumber caused by Pythium ultimum. Enterobacter cloacae strain C10 is a mini-Tn5 Km transposon mutant of strain 501R3 that was deficient in colonization of cucumber seedlings, and significantly reduced in colo...

  3. Enhanced dark hydrogen fermentation by addition of ferric oxide nanoparticles using Enterobacter aerogenes.

    PubMed

    Lin, Richen; Cheng, Jun; Ding, Lingkan; Song, Wenlu; Liu, Min; Zhou, Junhu; Cen, Kefa

    2016-05-01

    Ferric oxide nanoparticles (FONPs) were used to facilitate dark hydrogen fermentation using Enterobacter aerogenes. The hydrogen yield of glucose increased from 164.5±2.29 to 192.4±1.14mL/g when FONPs concentration increased from 0 to 200mg/L. SEM images of E. aerogenes demonstrated the existence of bacterial nanowire among cells, suggesting FONPs served as electron conduits to enhance electron transfer. TEM showed cellular internalization of FONPs, indicating hydrogenase synthesis and activity was potentially promoted due to the released iron element. When further increasing FONPs concentration to 400mg/L, the hydrogen yield of glucose decreased to 147.2±2.54mL/g. Soluble metabolic products revealed FONPs enhanced acetate pathway of hydrogen production, but weakened ethanol pathway. This shift of metabolic pathways allowed more nicotinamide adenine dinucleotide for reducing proton to hydrogen. PMID:26890796

  4. Evaluating Hawaii-Grown Papaya for Resistance to Internal Yellowing Disease Caused by Enterobacter cloacae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Papaya (Carica papaya L.) cultivars and breeding lines were evaluated for resistance to Enterobacter cloacae (Jordan) Hormaeche & Edwards, the bacterial causal agent of internal yellowing disease (IY), using a range of concentrations of the bacterium. Linear regression analysis was performed and IY ...

  5. Retrospective analysis of bacteremia because of Enterobacter cloacae compared with Escherichia coli bacteremia.

    PubMed

    Juanjuan, D; Zhiyong, Z; Xiaoju, L; Yali, X; Xihai, Z; Zhenzhen, L

    2007-04-01

    A total of 52 patients of Enterobacter cloacae bacteremia from a University hospital during the period from January 2000 to June 2005 were analysed and compared with a reference group comprising 52 patients of Escherichia coli bacteremia. Overall, E. cloacae ranked the tenth in all pathogens of bacteremia accounting for 2.8% of the total patients. Although the incidence of E. cloacae bacteremia was low, the attributable mortality rate till achieved 13.5%. Most patients (86.5%) with E. cloacae bacteremia were hospital-acquired. The overwhelming majority of patients (92.3%) were men, while almost half of the patients (48.1%) were from the Department of Urological Surgery with underlying diseases such as urinal obstruction, kidney transplantation and kidney tumours. Possible risks factors associated with E. cloacae bacteremia included immunocompromised status, long-term hospitalisation and invasive procedures or surgeries. E. cloacae bacteremia significantly differed from E. coli bacteremia in a number of clinical aspects, including underlying diseases, portal of entry, infection type, risks factors, laboratory findings and appropriateness of empirical antibiotic therapy. Besides the high prevalence of resistance to cephalosporins, most E. cloacae blood isolates were also resistant to ciprofloxacin (resistance rate, 67.3%), gentamicin (73.1%) and tobramycin (73.1%). Based on the findings of the present study, E. cloacae is probably an important pathogen of bacteremia occurring in male patients with underlying urinal system illnesses. PMID:17394432

  6. Association of antibiotic resistance with SHV-12 extended-spectrum β-lactamase in Enterobacter cloacae

    PubMed Central

    LIU, JUN; LI, GUO-MING; LIN, LI-YAO; WU, XIA-LEI; HUANG, SHAO-LONG; ZHOU, YONG; ZHAO, ZU-GUO

    2016-01-01

    The association between antibiotic resistance and SHV-12 extended-spectrum β-lactamase (ESBL) in Enterobacter cloacae remains unknown. The aim of the present study was to investigate the prevalence of both chromosome- and plasmid-borne SHV-12 ESBL genes in Enterobacter cloacae. Transmission of the SHV-12 ESBL gene was explored, and the risk factors for antibiotic resistance in E. cloacae were analyzed. Polymerase chain reaction (PCR) results showed that 58 out of the 100 isolates carried the SHV-12 ESBL gene: 34.48% of them occurred in the chromosome, 48.28% were plasmid-borne and 17.24% appeared in both. Enterobacterial repetitive intergenic consensus-PCR tests detected 82 chromosomal genotypes. Conjugation assays showed that 70.00% of plasmid-borne SHV-12 ESBL genes were successfully transconjugated into E. coli C600 and that the antibiotic resistance phenotype of E. cloacae was partially (84%) or completely (10%) transferred. A significantly higher SHV-12 ESBL detection rate was found in patients with underlying conditions and/or complications compared with those without (P<0.05). The detection of SHV-12 ESBL-producing E. cloacae from vertical transmission varied significantly across clinical departments and age groups (P<0.05), with the highest rates in the intensive care unit and the group of patients aged ≥60 years. The present results indicate that the location and transmission efficiency of SHV-12 ESBL are closely correlated with the antibiotic resistance of E. cloacae. PMID:26889253

  7. A Multiple Antibiotic-Resistant Enterobacter cloacae Strain Isolated from a Bioethanol Fermentation Facility

    PubMed Central

    Murphree, Colin A.; Li, Qing; Heist, E. Patrick; Moe, Luke A.

    2014-01-01

    An Enterobacter cloacae strain (E. cloacae F3S3) that was collected as part of a project to assess antibiotic resistance among bacteria isolated from bioethanol fermentation facilities demonstrated high levels of resistance to antibiotics added prophylactically to bioethanol fermentors. PCR assays revealed the presence of canonical genes encoding resistance to penicillin (ampC) and erythromycin (ermG). Assays measuring biofilm formation under antibiotic stress indicated that erythromycin induced biofilm formation in E. cloacae F3S3. Planktonic growth and biofilm formation were observed at a high ethanol content, indicating E. cloacae F3S3 can persist in a bioethanol fermentor under the highly variable environmental conditions found in fermentors. PMID:24941895

  8. A multiple antibiotic-resistant enterobacter cloacae strain isolated from a bioethanol fermentation facility.

    PubMed

    Murphree, Colin A; Li, Qing; Heist, E Patrick; Moe, Luke A

    2014-09-17

    An Enterobacter cloacae strain (E. cloacae F3S3) that was collected as part of a project to assess antibiotic resistance among bacteria isolated from bioethanol fermentation facilities demonstrated high levels of resistance to antibiotics added prophylactically to bioethanol fermentors. PCR assays revealed the presence of canonical genes encoding resistance to penicillin (ampC) and erythromycin (ermG). Assays measuring biofilm formation under antibiotic stress indicated that erythromycin induced biofilm formation in E. cloacae F3S3. Planktonic growth and biofilm formation were observed at a high ethanol content, indicating E. cloacae F3S3 can persist in a bioethanol fermentor under the highly variable environmental conditions found in fermentors. PMID:24941895

  9. Most Enterobacter aerogenes Strains in France Belong to a Prevalent Clone

    PubMed Central

    Bosi, Claude; Davin-Regli, Anne; Bornet, Charleric; Mallea, Monique; Pages, Jean-Marie; Bollet, Claude

    1999-01-01

    The aim of this study was to determine the distribution in France of the Enterobacter aerogenes prevalent clone isolated in the hospitals of the Marseille area (A. Davin-Regli, D. Monnet, P. Saux, C. Bosi, R. Charrel, A. Barthelemy, and C. Bollet, J. Clin. Microbiol. 34:1474–1480, 1996). A total of 123 E. aerogenes isolates were collected from 23 hospital laboratories and analyzed by random amplification of polymorphic DNA and enterobacterial repetitive intergenic consensus-PCR to determine their epidemiological relatedness. Molecular typing revealed that 21 of the 23 laboratories had isolated this prevalent clone harboring the plasmid encoding for extended-spectrum β-lactamase of the TEM-24 type. Most isolates were susceptible only to imipenem and gentamicin. Their dissemination seems to be clonal and was probably the result of the general use of broad-spectrum cephalosporins and quinolones. Four isolates showed an alteration of their outer membrane proteins, causing decrease of susceptibility to third-generation cephalosporins and imipenem and leading to the critical situation of having no alternative therapeutic. The large dissemination of the E. aerogenes prevalent clone probably results from its good adaptation to the antibiotics administered in France and the hospital environment, particularly in intensive care units. PMID:10364580

  10. Biodegradation of 2-methylquinoline by Enterobacter aerogenes TJ-D isolated from activated sludge.

    PubMed

    Wang, Lin; Li, Yongmei; Duan, Jingyuan

    2013-07-01

    Bacterial strain Enterobacter aerogenes TJ-D capable of utilizing 2-methylquinoline as the sole carbon and energy source was isolated from acclimated activated sludge under denitrifying conditions. The ability to degrade 2-methylquinoline by E. aerogenes TJ-D was investigated under denitrifying conditions. Under optimal conditions of temperature (35 degrees C) and initial pH 7, 2-methylquinoline of 100 mg/L was degraded within 176 hr. The degradation of 2-methylquinoline by E. aerogenes TJ-D could be well described by the Haldane model (R2 > 0.91). During the degradation period of 2-methylquinoline (initial concentration 100 mg/L), nitrate was almost completely consumed (the removal efficiency was 98.5%), while nitrite remained at low concentration (< 0.62 mg/L) during the whole denitrification period. 1,2,3,4-Tetrahydro-2-methylquinoline, 4-ethyl-benzenamine, N-butyl-benzenamine, N-ethyl-benzenamine and 2,6-diethyl-benzenamine were metabolites produced during the degradation. The degradation pathway of 2-methylquinoline by E. aerogenes TJ-D was proposed. 2-Methylquinoline is initially hydroxylated at C-4 to form 2-methyl-4-hydroxy-quinoline, and then forms 2-methyl-4-quinolinol as a result of tautomerism. Hydrogenation of the heterocyclic ring at positions 2 and 3 produces 2,3-dihydro-2-methyl-4-quinolinol. The carbon-carbon bond at position 2 and 3 in the heterocyclic ring may cleave and form 2-ethyl-N-ethyl-benzenamine. Tautomerism may result in the formation of 2,6-diethyl-benzenamine and N-butyl-benzenamine. 4-Ethyl-benzenamine and N-ethyl-benzenamine were produced as a result of losing one ethyl group from the above molecules. PMID:24218841

  11. Extreme furfural tolerance of a soil bacterium Enterobacter cloacae GGT036.

    PubMed

    Choi, Sun Young; Gong, Gyeongtaek; Park, Hong-Sil; Um, Youngsoon; Sim, Sang Jun; Woo, Han Min

    2015-01-10

    Detoxification process of cellular inhibitors including furfural is essential for production of bio-based chemicals from lignocellulosic biomass. Here we isolated an extreme furfural-tolerant bacterium Enterobacter cloacae GGT036 from soil sample collected in Mt. Gwanak, Republic of Korea. Among isolated bacteria, only E. cloacae GGT036 showed cell growth with 35 mM furfural under aerobic culture. Compared to the maximal half inhibitory concentration (IC50) of well-known industrial strains Escherichia coli (24.9 mM furfural) and Corynebacterium glutamicum (10 mM furfural) based on the cell density, IC50 of E. cloacae GGT036 (47.7 mM) was significantly higher after 24 h, compared to E. coli and C. glutamicum. Since bacterial cell growth was exponentially inhibited depending on linearly increased furfural concentrations in the medium, we concluded that E. cloacae GGT036 is an extreme furfural-tolerant bacterium. Recently, the complete genome sequence of E. cloacae GGT036 was announced and this could provide an insight for engineering of E. cloacae GGT036 itself or other industrially relevant bacteria. PMID:25444876

  12. Production of Internal Yellowing Symptoms on Resistant and Susceptible Papaya Cultivars by Enterobacter cloacae at Varying Inoculum Concentrations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Internal yellowing (IY) is a bacterial disease of ripening papaya flesh caused by Enterobacter cloacae and characterized by yellow softening tissue. IY restricts food safety of value-added products like fresh or frozen papaya cubes. The incidence of E. cloacae presumably differs in resistant (R) a...

  13. Study of the role of anaerobic metabolism in succinate production by Enterobacter aerogenes.

    PubMed

    Tajima, Yoshinori; Kaida, Kenichi; Hayakawa, Atsushi; Fukui, Keita; Nishio, Yousuke; Hashiguchi, Kenichi; Fudou, Ryosuke; Matsui, Kazuhiko; Usuda, Yoshihiro; Sode, Koji

    2014-09-01

    Succinate is a core biochemical building block; optimizing succinate production from biomass by microbial fermentation is a focus of basic and applied biotechnology research. Lowering pH in anaerobic succinate fermentation culture is a cost-effective and environmentally friendly approach to reducing the use of sub-raw materials such as alkali, which are needed for neutralization. To evaluate the potential of bacteria-based succinate fermentation under weak acidic (pH <6.2) and anaerobic conditions, we characterized the anaerobic metabolism of Enterobacter aerogenes AJ110637, which rapidly assimilates glucose at pH 5.0. Based on the profile of anaerobic products, we constructed single-gene knockout mutants to eliminate the main anaerobic metabolic pathways involved in NADH re-oxidation. These single-gene knockout studies showed that the ethanol synthesis pathway serves as the dominant NADH re-oxidation pathway in this organism. To generate a metabolically engineered strain for succinate production, we eliminated ethanol formation and introduced a heterogeneous carboxylation enzyme, yielding E. aerogenes strain ΔadhE/PCK. The strain produced succinate from glucose with a 60.5% yield (grams of succinate produced per gram of glucose consumed) at pH <6.2 and anaerobic conditions. Thus, we showed the potential of bacteria-based succinate fermentation under weak acidic conditions. PMID:24962116

  14. Effect of nanocomposite packaging containing ZnO on growth of Bacillus subtilis and Enterobacter aerogenes.

    PubMed

    Esmailzadeh, Hakimeh; Sangpour, Parvaneh; Shahraz, Farzaneh; Hejazi, Jalal; Khaksar, Ramin

    2016-01-01

    Recent advances in nanotechnology have opened new windows in active food packaging. Nano-sized ZnO is an inexpensive material with potential antimicrobial properties. The aim of the present study is to evaluate the antibacterial effect of low density Polyethylene (LDPE) containing ZnO nanoparticles on Bacillus subtilis and Enterobacter aerogenes. ZnO nanoparticles have been synthesized by facil molten salt method and have been characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM). Nanocomposite films containing 2 and 4 wt.% ZnO nanoparticles were prepared by melt mixing in a twin-screw extruder. The growth of both microorganisms has decreased in the presence of ZnO containing nanocomposites compared with controls. Nanocomposites with 4 wt.% ZnO nanoparticles had stronger antibacterial effect against both bacteria in comparison with the 2 wt.% ZnO containing nanocomposites. B. subtilis as Gram-positive bacteria were more sensitive to ZnO containing nanocomposite films compared with E. aerogenes as Gram-negative bacteria. There were no significant differences between the migration of Zn ions from 2 and 4 wt.% ZnO containing nanocomposites and the released Zn ions were not significantly increased in both groups after 14 days compared with the first. Regarding the considerable antibacterial effects of ZnO nanoparticles, their application in active food packaging can be a suitable solution for extending the shelf life of food. PMID:26478403

  15. Enhancing hydrogen production of Enterobacter aerogenes by heterologous expression of hydrogenase genes originated from Synechocystis sp.

    PubMed

    Song, Wenlu; Cheng, Jun; Zhao, Jinfang; Zhang, Chuanxi; Zhou, Junhu; Cen, Kefa

    2016-09-01

    The hydrogenase genes (hoxEFUYH) of Synechocystis sp. PCC 6803 were cloned and heterologously expressed in Enterobacter aerogenes ATCC13408 for the first time in this study, and the hydrogen yield was significantly enhanced using the recombinant strain. A recombinant plasmid containing the gene in-frame with Glutathione-S-Transferase (GST) gene was transformed into E. aerogenes ATCC13408 to produce a GST-fusion protein. SDS-PAGE and western blot analysis confirm the successful expression of the hox genes. The hydrogenase activity of the recombinant strain is 237.6±9.3ml/(g-DW·h), which is 152% higher than the wild strain. The hydrogen yield of the recombinant strain is 298.3ml/g-glucose, which is 88% higher than the wild strain. During hydrogen fermentation, the recombinant strain produces more acetate and butyrate, but less ethanol. This is corresponding to the NADH metabolism in the cell due to the higher hydrogenase activity with the heterologous expression of hox genes. PMID:27343449

  16. Particular Distribution of Enterobacter cloacae Strains Isolated from Urinary Tract Infection within Clonal Complexes

    PubMed Central

    Akbari, Majid; Bakhshi, Bita; Najar Peerayeh, Shahin

    2016-01-01

    Background: Based on biochemical properties, Enterobacter cloacae represents a large complex of at least 13 variant species, subspecies, and genotypes that progressively identified as the most species causing hospital-acquired infections. The aim of this study was to determine the relevance between phylogenetically related strains within the E. cloacae complex and the frequency of urinary tract infection caused by them. Methods: A 268-bp fragment was obtained from hsp60 gene for 50 clinical E. cloacae isolates from urine cultures of inpatients that admitted to six hospitals in Tehran, Iran during December 2012 to November 2013. The 107 nucleotide sequences were analyzed and the evolutionary distances of sequences were computed and neighbor-joining tree was calculated. Results: It showed that all of the genetic clusters have not an equal involvement in pathogenesis of urinary tract infections. Three superior clusters were found, together representing more than two third (80%) of the isolates (cluster VI with 25 members; clusters III and VIII with 9 and 6 members, respectively) and some genetic clusters were absent (IV, X, XII, and xiii), some of which are supposed to be associated with plants and no human infection has been reported. Conclusions: This study, for the first time, reports the unequal contribution of E. cloacae complex subspecies and clusters in urinary tract infections in Iran and together with studies from other countries suggest that the subspecies of E.hormaechei subsp. Oharae is the most prevalent E. cloacae complex subspecies regardless of country under study. PMID:26498349

  17. Plant growth promoting bacteria Enterobacter asburiae JAS5 and Enterobacter cloacae JAS7 in mineralization of endosulfan.

    PubMed

    Abraham, Jayanthi; Silambarasan, Sivagnanam

    2015-04-01

    Endosulfan and their metabolites can be detected in soils with a history of endosulfan application. Microbial degradation offers an effective approach to remove toxicants, and in this study, Enterobacter asburiae JAS5 and Enterobacter cloacae JAS7 were isolated through enrichment technique. The biodegradation of endosulfan and its metabolites rate constant (k) and DT50 were determined through first-order kinetic models. E. asburiae JAS5 degraded the endosulfan, and its metabolites in liquid medium was characterized by the k which was 0.382 day(-1) (α-endosulfan), 0.284 day(-1) (β-endosulfan) and 0.228 day(-1) (endosulfan sulphate), and DT50 was 1.8 day (α-endosulfan), 2.4 days (β-endosulfan) and 3.0 days (endosulfan sulphate). The α-endosulfan, β-endosulfan and endosulfan sulphate metabolites were present in the liquid medium that was degraded by E. cloacae JAS7 which was characterized by the k of 0.391, 0.297 day(-1) and 0.273 day(-1), and DT50 was 1.7, 2.3 and 2.5 days, respectively. The infrared spectrum of endosulfan degraded sample in the aqueous medium by E. asburiae JAS5 and E. cloacae JAS7 showed a band at 1402 cm(-1) which is the characteristics of COOH group. E. asburiae JAS5 and E. cloacae JAS7 strains also showed the ability of plant growth promoting traits such as indole-3-acetic acid (IAA) production, organic acids production and solubilization of various inorganic phosphates. E. asburiae JAS5 solubilized 324 ± 2 μg ml(-1) of tricalcium phosphate, 296 ± 6 μg ml(-1) of dicalcium phosphate and 248 ± 5 μg ml(-1) of zinc phosphate, whereas E. cloacae JAS7 solubilized 338 ± 5, 306 ± 4 and 268 ± 3 μg ml(-1) of tricalcium phosphate, dicalcium phosphate and zinc phosphate, respectively. The IAA production by JAS5 and JAS7 strains were estimated to be 38.6 ± 0.3 and 46.6 ± 0.5 μg ml(-1), respectively. These bacterial strains form a potential candidate for bioremediation of pesticide-contaminated agricultural

  18. Subtractive Hybridization Yields a Silver Resistance Determinant Unique to Nosocomial Pathogens in the Enterobacter cloacae Complex

    PubMed Central

    Hoffmann, Harald

    2012-01-01

    The heterogeneity and the increasing clinical importance of the Enterobacter cloacae complex have often been discussed. However, little is known about molecular factors causing pathogenicity within this nomenspecies. Here, we analyzed the genetic differences between an avirulent plant isolate and a pathogenic strain causing an outbreak with septicemia in three patients. We identified an IncHI-2 plasmid as a major difference between these two strains. Besides resistance to several antibiotics, this plasmid encoded a silver resistance determinant. We further showed that this sil determinant was present not only in the analyzed outbreak strain but also in the vast majority of clinical isolates of the E. cloacae complex, predominantly in (sub)species that frequently cause nosocomial infections. The identified sil determinant was highly conserved within the E. cloacae complex and mediated resistance to up to 600 μM silver nitrate. As silver is often used as a disinfectant and treatment for burn wounds, we present here an important fitness factor within the clinically most prevalent subspecies of the E. cloacae complex. This provides a possible explanation for their unequal involvement in nosocomial and especially burn wound infections. PMID:22837330

  19. Draft Genome Sequence of Enterobacter aerogenes, a DDE-Degrading and Plant Growth-Promoting Strain Isolated from Cucurbita pepo

    PubMed Central

    Eevers, Nele; Van Hamme, Jonathan D.; Bottos, Eric M.; Weyens, Nele

    2015-01-01

    We report here the draft genome of Enterobacter aerogenes, a Gram-negative bacterium of the Enterobacteriaceae isolated from Cucurbita pepo root tissue. This bacterium shows 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (DDE)-degrading potential and plant growth-promoting capacity. An analysis of its 4.5-Mb draft genome will enhance the understanding of DDE degradation pathways and phytoremediation applications for DDE-contaminated soils. PMID:25883299

  20. Structure and gene cluster of the O-antigen of Enterobacter cloacae G3421.

    PubMed

    Perepelov, Andrei V; Filatov, Andrei V; Wang, Min; Shashkov, Alexander S; Wang, Lei; Knirel, Yuriy A

    2016-06-01

    The O-polysaccharide was isolated by mild acid degradation of the lipopolysaccharide of Enterobacter cloacae G3421 and studied by sugar analysis along with 1D and 2D (1)H and (13)C NMR spectroscopy. In addition, partial solvolysis with anhydrous trifluoroacetic acid was applied, which cleaved selectively the α-l-rhamnopyranosidic linkages. The following structure of the branched hexasaccharide repeating unit was established. The O-polysaccharide studied shares the β-l-Rhap-(1→4)-α-l-Rhap-(1→2)-α-l-Rhap trisaccharide fragment with the O-polysaccharide of Shigella boydii type 18. The O-antigen gene cluster of E. cloacae G3421 was sequenced. Functions of genes in the cluster, including those for glycosyltransferases, were tentatively assigned by a comparison with sequences in the available databases and found to be consistent with the O-polysaccharide structure. PMID:27131290

  1. Induction of beta-lactamase by various beta-lactam antibiotics in Enterobacter cloacae.

    PubMed Central

    Minami, S; Yotsuji, A; Inoue, M; Mitsuhashi, S

    1980-01-01

    The induction of beta-lactamase in Enterobacter cloacae GN5797 was studied by using 23 beta-lactam antiobiotics, including newly introduced drugs, as inducers. the beta-lactam antibiotics can be classified into three groups on the basis of their inducer activity. Among the tested cephalosporins, cephamycin derivatives such as cefoxitin, cefmetazole, and YM09330 had high inducer activity even at low drug concentrations. On the other hand, cefoperazone, cefsulodin, piperacillin, and apalcillin showed low inducer activity when compared with the other cephalosporins. PMID:6968541

  2. KPC and VIM producing Enterobacter cloacae strain from a hospital in northeastern Venezuela.

    PubMed

    Martínez, Dianny; Marcano, Daniel; Rodulfo, Hectorina; Salgado, Nurys; Cuaical, Nirvia; Rodriguez, Lucy; Caña, Luisa; Medina, Belkis; Guzman, Militza; De Donato, Marcos

    2015-06-01

    An 83-year-old male patient is admitted to the central hospital in Cumana, Venezuela with severe urinary infection, history of hospitalizaions and prolonged antimicrobial treatments. A strain of Enterobacter cloacae was isolated showing resistance to multiple types of antibiotics (only sensitive to gentamicin), with phenotype of serine- and metallo-carbapenemases. Both, bla(VIM-2) and bla(KPC) genes were detected in the isolate. This is the first report of an Enterobacteriaceae species producing both KPC carbapenemase and VIM metallo carbapenemase in Venezuela. This finding has a great clinical and epidemiological impact in the region, because of the feasibility of transferring these genes, through mobile elements to other strains of Enterobacter and to other infection-causing species of bacteria. PMID:26299058

  3. Optimization of cultural conditions for conversion of glycerol to ethanol by Enterobacter aerogenes S012.

    PubMed

    Nwachukwu, Raymond E S; Shahbazi, Abolghasem; Wang, Lijun; Worku, Mulumebet; Ibrahim, Salam; Schimmel, Keith

    2013-01-01

    The aim of this research is to optimize the cultural conditions for the conversion of glycerol to ethanol by Enterobacter aerogenes S012. Taguchi method was used to screen the cultural conditions based on their signal to noise ratio (SN). Temperature (°C), agitation speed (rpm) and time (h) were found to have the highest influence on both glycerol utilization and ethanol production by the organism while pH had the lowest. Full factorial design, statistical analysis, and regression model equation were used to optimize the selected cultural parameters for maximum ethanol production. The result showed that fermentation at 38°C and 200 rpm for 48 h would be ideal for the bacteria to produce maximum amount of ethanol from glycerol. At these optimum conditions, ethanol production, yield and productivity were 25.4 g/l, 0.53 g/l/h, and 1.12 mol/mol-glycerol, repectively. Ethanol production increased to 26.5 g/l while yield and productivity decreased to 1.04 mol/mol-glycerol and 0.37 g/l/h, respectively, after 72 h. Analysis of the fermentation products was performed using HPLC, while anaerobic condition was created by purging the fermentation vessel with nitrogen gas. PMID:23388539

  4. Optimization of cultural conditions for conversion of glycerol to ethanol by Enterobacter aerogenes S012

    PubMed Central

    2013-01-01

    The aim of this research is to optimize the cultural conditions for the conversion of glycerol to ethanol by Enterobacter aerogenes S012. Taguchi method was used to screen the cultural conditions based on their signal to noise ratio (SN). Temperature (°C), agitation speed (rpm) and time (h) were found to have the highest influence on both glycerol utilization and ethanol production by the organism while pH had the lowest. Full factorial design, statistical analysis, and regression model equation were used to optimize the selected cultural parameters for maximum ethanol production. The result showed that fermentation at 38°C and 200 rpm for 48 h would be ideal for the bacteria to produce maximum amount of ethanol from glycerol. At these optimum conditions, ethanol production, yield and productivity were 25.4 g/l, 0.53 g/l/h, and 1.12 mol/mol-glycerol, repectively. Ethanol production increased to 26.5 g/l while yield and productivity decreased to 1.04 mol/mol-glycerol and 0.37 g/l/h, respectively, after 72 h. Analysis of the fermentation products was performed using HPLC, while anaerobic condition was created by purging the fermentation vessel with nitrogen gas. PMID:23388539

  5. Enterobacter cloacae Sacroiliitis with Acute Respiratory Distress Syndrome in an Adolescent

    PubMed Central

    Kim, Jin Soo; Ko, Jeong Hee; Lee, Seunghun; Jeon, Seok Chol

    2015-01-01

    Enterobacter cloacae has emerged as an important nosocomial pathogen, but is rarely a cause of sacroiliitis. Herein, we present the first reported case of Enterobacter cloacae sacroiliitis associated with sepsis and acute respiratory distress syndrome (ARDS). A previously healthy 14-year-old boy presented with low-grade fever and pain in the left side of the hip that was aggravated by walking. Pelvic computed tomography (CT) showed normal findings, and the patient received supportive care for transient synovitis with no antibiotics. However, there was no clinical improvement. On the third day of hospitalization, magnetic resonance imaging of the hip revealed findings compatible with sacroiliitis, for which vancomycin and ceftriaxone were administered. The patient suddenly developed high fever with dyspnea. Chest radiography and CT findings and a PaO2/FiO2 ratio <200 mmHg were suggestive of ARDS; the patient subsequently received ventilatory support and low-dose methylprednisolone infusions. Within one week, defervescence occurred, and the patient was able to breathe on his own. Following the timely recognition of, and therapeutic challenge to, ARDS, and after 6 weeks of parenteral antimicrobial therapy, the patient was discharged in good health with no complications. PMID:26157593

  6. Identification of sdiA-regulated genes in a mouse commensal strain of Enterobacter cloacae

    PubMed Central

    Sabag-Daigle, Anice; Dyszel, Jessica L.; Gonzalez, Juan F.; Ali, Mohamed M.; Ahmer, Brian M. M.

    2015-01-01

    Many bacteria determine their population density using quorum sensing. The most intensively studied mechanism of quorum sensing utilizes proteins of the LuxI family to synthesize a signaling molecule of the acylhomoserine lactone (AHL) type, and a protein of the LuxR family to bind AHL and regulate transcription. Genes regulated by quorum sensing often encode functions that are most effective when a group of bacteria are working cooperatively (e.g., luminescence, biofilm formation, host interactions). Bacteria in the Escherichia, Salmonella, Klebsiella, and Enterobacter genera do not encode an AHL synthase but they do encode an AHL receptor of the LuxR family, SdiA. Instead of detecting their own AHL synthesis, these organisms use SdiA to detect the AHLs synthesized by other bacterial species. In this study, we used a genetic screen to identify AHL-responsive genes in a commensal Enterobacter cloacae strain that was isolated from a laboratory mouse. The genes include a putative type VI secretion system, copA (a copper transporter), and fepE (extends O-antigen chain length). A new transposon mutagenesis strategy and suicide vectors were used to construct an sdiA mutant of E. cloacae. The AHL-responsiveness of all fusions was entirely sdiA-dependent, although some genes were regulated by sdiA in the absence of AHL. PMID:26075189

  7. Protective effect of amdinocillin against emergence of resistance to ceftazidime in Enterobacter cloacae.

    PubMed Central

    Yourassowsky, E; van der Linden, M P; Lismont, M J; Crokaert, F; Glupczynski, Y

    1988-01-01

    Enterobacter cloacae infections have been shown clinically to respond less reliably to monotherapy with broad-spectrum cephalosporins than was initially expected. Selection of populations producing high levels of beta-lactamase has been shown to be the most frequent reason for treatment failure, and the use of these agents with another active antibiotic is recommended. In this study, E. cloacae strains from clinical specimens susceptible to ceftazidime and amdinocillin by broth dilution and disk tests were examined. In the presence of ceftazidime at 10 micrograms/ml, in vitro selection of resistant organisms was demonstrated for 3 of 11 strains. Selection was prevented when amdinocillin was added in combination. A more rapid killing was also demonstrated with this combination. At inocula of 10(8) CFU/ml, ceftazidime-resistant populations were isolated from 6 of 11 strains in vitro, and the emergence of this resistance was prevented by amdinocillin. The enhanced killing effect noted for amdinocillin with ceftazidime may have resulted in part from complementary activity of the antibiotics on penicillin-binding proteins. The ceftazidime-amdinocillin combination offers an interesting prospect for the therapy of infections caused by E. cloacae strains which are initially susceptible to both antibiotics. PMID:3075433

  8. Modelling the interactions between Lactobacillus curvatus and Enterobacter cloacae. II. Mixed cultures and shelf life predictions.

    PubMed

    Malakar, P K; Martens, D E; Zwietering, M H; Béal, C; van 't Riet, K

    1999-10-01

    The modelling approach presented in this study can be used to predict when interactions between microorganisms in homogenous systems occur. It was tested for the interaction between Lactobacillus curvatus and Enterobacter cloacae. In this binary system, L. curvatus produces lactic acid which decreases the pH in the system. The pH decrease was found to be the main limiting factor of growth of both E. cloacae and L. curvatus. This resulted in E. cloacae reaching its final concentration earlier when compared to its growth in pure culture. The models consisted of a set of first order ordinary differential equations describing the growth, consumption and production rates of both microorganisms. The parameters for these equations were obtained from pure culture studies and from literature. These equations were solved using a combination of analytical and numerical methods. The prediction of growth in mixed culture using parameters from pure culture experiments and literature were close to the experimental data. Both model predictions and experimental validation indicated that interaction occurs when the concentration of L. curvatus reaches 10(8) cfu/ml. At that moment in time, the pH had decreased to inhibiting levels. These concentrations of microorganisms (10(8) cfu/ml) do occur in fermented products where interactions obviously are important. In nonfermented foods however, this level of microorganisms indicate that spoilage has occurred or is about to start. Microbial interactions can therefore be neglected when predicting shelf life or safety of food products in most cases. PMID:10563464

  9. Isolation and characterization of a glyphosate-degrading rhizosphere strain, Enterobacter cloacae K7.

    PubMed

    Kryuchkova, Yelena V; Burygin, Gennady L; Gogoleva, Natalia E; Gogolev, Yuri V; Chernyshova, Marina P; Makarov, Oleg E; Fedorov, Evgenii E; Turkovskaya, Olga V

    2014-01-20

    Plant-growth-promoting rhizobacteria exert beneficial effects on plants through their capacity for nitrogen fixation, phytohormone production, phosphate solubilization, and improvement of the water and mineral status of plants. We suggested that these bacteria may also have the potential to express degradative activity toward glyphosate, a commonly used organophosphorus herbicide. In this study, 10 strains resistant to a 10 mM concentration of glyphosate were isolated from the rhizoplane of various plants. Five of these strains--Alcaligenes sp. K1, Comamonas sp. K4, Azomonas sp. K5, Pseudomonas sp. K3, and Enterobacter cloacae K7--possessed a number of associative traits, including fixation of atmospheric nitrogen, solubilization of phosphates, and synthesis of the phytohormone indole-3-acetic acid. One strain, E. cloacae K7, could utilize glyphosate as a source of P. Gas-liquid chromatography showed that E. cloacae growth correlated with a decline in herbicide content in the culture medium (40% of the initial 5mM content), with no glyphosate accumulating inside the cells. Thin-layer chromatography analysis of the intermediate metabolites of glyphosate degradation found that E. cloacae K7 had a C-P lyase activity and degraded glyphosate to give sarcosine, which was then oxidized to glycine. In addition, strain K7 colonized the roots of common sunflower (Helianthus annuus L.) and sugar sorghum (Sorghum saccharatum Pers.), promoting the growth and development of sunflower seedlings. Our findings extend current knowledge of glyphosate-degrading rhizosphere bacteria and may be useful for developing a biotechnology for the cleanup and restoration of glyphosate-polluted soils. PMID:23545355

  10. Clonal Dissemination of Enterobacter cloacae Harboring blaKPC-3 in the Upper Midwestern United States

    PubMed Central

    Hargreaves, Melissa L.; Shaw, Kristin M.; Dobbins, Ginette; Snippes Vagnone, Paula M.; Harper, Jane E.; Boxrud, Dave; Lynfield, Ruth; Aziz, Maliha; Price, Lance B.; Silverstein, Kevin A. T.; Danzeisen, Jessica L.; Youmans, Bonnie; Case, Kyle; Sreevatsan, Srinand

    2015-01-01

    Carbapenemase-producing, carbapenem-resistant Enterobacteriaceae, or CP-CRE, are an emerging threat to human and animal health, because they are resistant to many of the last-line antimicrobials available for disease treatment. Carbapenemase-producing Enterobacter cloacae harboring blaKPC-3 recently was reported in the upper midwestern United States and implicated in a hospital outbreak in Fargo, North Dakota (L. M. Kiedrowski, D. M. Guerrero, F. Perez, R. A. Viau, L. J. Rojas, M. F. Mojica, S. D. Rudin, A. M. Hujer, S. H. Marshall, and R. A. Bonomo, Emerg Infect Dis 20:1583–1585, 2014, http://dx.doi.org/10.3201/eid2009.140344). In early 2009, the Minnesota Department of Health began collecting and screening CP-CRE from patients throughout Minnesota. Here, we analyzed a retrospective group of CP-E. cloacae isolates (n = 34) collected between 2009 and 2013. Whole-genome sequencing and analysis revealed that 32 of the strains were clonal, belonging to the ST171 clonal complex and differing collectively by 211 single-nucleotide polymorphisms, and it revealed a dynamic clone under positive selection. The phylogeography of these strains suggests that this clone existed in eastern North Dakota and western Minnesota prior to 2009 and subsequently was identified in the Minneapolis and St. Paul metropolitan area. All strains harbored identical IncFIA-like plasmids conferring a CP-CRE phenotype and an additional IncX3 plasmid. In a single patient with multiple isolates submitted over several months, we found evidence that these plasmids had transferred from the E. cloacae clone to an Escherichia coli ST131 bacterium, rendering it as a CP-CRE. The spread of this clone throughout the upper midwestern United States is unprecedented for E. cloacae and highlights the importance of continued surveillance to identify such threats to human health. PMID:26438492

  11. Demonstrating Pathogenicity of Enterobacter cloacae on Macadamia and Identifying Associated Volatiles of Gray Kernel of Macadamia in Hawaii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gray kernel is an important disease of macadamia that affects the quality of kernels, causing gray discoloration and a permeating, foul odor. Gray kernel symptoms were produced in raw, in-shell kernels of three cultivars of macadamia that were inoculated with strains of Enterobacter cloacae. Koch’...

  12. Association of Enterobacter cloacae and other bacteria with onion bulb rot in the Columbia Basin of Washington and Oregon, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Approximately 1.6 million metric tons of onion bulbs are produced annually in the Pacific Northwest USA. Bulb decay can be a major problem and is caused by a variety of plant pathogens. Onion bulbs exhibiting symptoms of bacterial rot were sampled to determine the causal agents. Enterobacter cloacae...

  13. Investigation and control of an outbreak of Enterobacter aerogenes bloodstream infection in a neonatal intensive care unit in Fiji.

    PubMed

    Narayan, Swastika A; Kool, Jacob L; Vakololoma, Miriama; Steer, Andrew C; Mejia, Amelita; Drake, Anne; Jenney, Adam; Turton, Jane F; Kado, Joseph; Tikoduadua, Lisi

    2009-08-01

    Ten neonates developed blood stream infection with extended-spectrum beta-lactamase-producing Enterobacter aerogenes in a neonatal intensive care unit in Fiji. The source of the outbreak was traced to a bag of contaminated normal saline in the ward, which was used for multiple patients. All isolates recovered from patients were indistinguishable from the bacteria recovered from the normal saline by pulsed-field gel electrophoresis. The outbreak was controlled using simple infection control practices such as reinforcement of strict hand hygiene policy, provision of single use vials of normal saline, and strict aseptic technique for injections. PMID:19552517

  14. Exopolysaccharide production by a genetically engineered Enterobacter cloacae strain for microbial enhanced oil recovery.

    PubMed

    Sun, Shanshan; Zhang, Zhongzhi; Luo, Yijing; Zhong, Weizhang; Xiao, Meng; Yi, Wenjing; Yu, Li; Fu, Pengcheng

    2011-05-01

    Microbial enhanced oil recovery (MEOR) is a petroleum biotechnology for manipulating function and/or structure of microbial environments existing in oil reservoirs for prolonged exploitation of the largest source of energy. In this study, an Enterobacter cloacae which is capable of producing water-insoluble biopolymers at 37°C and a thermophilic Geobacillus strain were used to construct an engineered strain for exopolysaccharide production at higher temperature. The resultant transformants, GW3-3.0, could produce exopolysaccharide up to 8.83 g l(-1) in molasses medium at 54°C. This elevated temperature was within the same temperature range as that for many oil reservoirs. The transformants had stable genetic phenotype which was genetically fingerprinted by RAPD analysis. Core flooding experiments were carried out to ensure effective controlled profile for the simulation of oil recovery. The results have demonstrated that this approach has a promising application potential in MEOR. PMID:21444201

  15. Characteristics of a Novel Aerobic Denitrifying Bacterium, Enterobacter cloacae Strain HNR.

    PubMed

    Guo, Long-Jie; Zhao, Bin; An, Qiang; Tian, Meng

    2016-03-01

    A novel aerobic denitrifier strain HNR, isolated from activated sludge, was identified as Enterobacter cloacae by16S rRNA sequencing analysis. Glucose was considered as the most favorable C-source for strain HNR. The logistic equation well described the bacterial growth, yielding a maximum growth rate (μmax) of 0.283 h(-1) with an initial NO3 (-)-N concentration of 110 mg/L. Almost all NO3 (-)-N was removed aerobically within 30 h with an average removal rate of 4.58 mg N L(-1) h(-1). Nitrogen balance analysis revealed that proximately 70.8 % of NO3 (-)-N was removed as gas products and only 20.7 % was transformed into biomass. GC-MS result indicates that N2 was the end product of aerobic denitrification. The enzyme activities of nitrate reductase and nitrite reductase, which are related to the process of aerobic denitrification, were 0.0688 and 0.0054 U/mg protein, respectively. Thus, the aerobic denitrification of reducing NO3 (-) to N2 by strain HNR was demonstrated. The optimal conditions for nitrate removal were C/N ratio 13, pH value 8, shaking speed 127 rpm and temperature 30 °C. These findings show that E. cloacae strain HNR has a potential application on wastewater treatment to achieve nitrate removal under aerobic conditions. PMID:26573667

  16. Proteomic response of β-lactamases-producing Enterobacter cloacae complex strain to cefotaxime-induced stress.

    PubMed

    Maravić, Ana; Cvjetan, Svjetlana; Konta, Marina; Ladouce, Romain; Martín, Fernando A

    2016-07-01

    Bacteria of the Enterobacter cloacae complex are among the ten most common pathogens causing nosocomial infections in the USA. Consequently, increased resistance to β-lactam antibiotics, particularly expanded-spectrum cephalosporins like cefotaxime (CTX), poses a serious threat. Differential In-Gel Electrophoresis (DIGE), followed by LC-MS/MS analysis and bioinformatics tools, was employed to investigate the survival mechanisms of a multidrug-resistant E. hormaechei subsp. steigerwaltii 51 carrying several β-lactamase-encoding genes, including the 'pandemic' blaCTX-M-15 After exposing the strain with sub-minimal inhibitory concentration (MIC) of CTX, a total of 1072 spots from the whole-cell proteome were detected, out of which 35 were differentially expressed (P ≤ 0.05, fold change ≥1.5). Almost 50% of these proteins were involved in cell metabolism and energy production, and then cell wall organization/virulence, stress response and transport. This is the first study investigating the whole-cell proteomic response related to the survival of β-lactamases-producing strain, belonging to the E. cloacae complex when exposed to β-lactam antibiotic. Our data support the theory of a multifactorial synergistic effect of diverse proteomic changes occurring in bacterial cells during antibiotic exposure, depicting the complexity of β-lactam resistance and giving us an insight in the key pathways mediating the antibiotic resistance in this emerging opportunistic pathogen. PMID:27162211

  17. Acanthamoeba castellanii of the T4 genotype is a potential environmental host for Enterobacter aerogenes and Aeromonas hydrophila

    PubMed Central

    2013-01-01

    Background Acanthamoeba can interact with a wide range of microorganisms such as viruses, algae, yeasts, protists and bacteria including Legionella pneumophila, Pseudomonas aeruginosa, Vibrio cholerae, Helicobacter pylori, Listeria monocytogenes, Mycobacterium spp., and Escherichia coli. In this capacity, Acanthamoeba has been suggested as a vector in the transmission of bacterial pathogens to the susceptible hosts. Methods Here, we used a keratitis isolate of A. castellanii of the T4 genotype and studied its interactions with two bacterial genera which have not been tested before, Enterobacter aerogenes, and Aeromonas hydrophila, as well as E. coli. Assays were performed to determine bacterial association with and invasion of A. castellanii. Additionally, bacterial survival intracellular of A. castellanii trophozoites as well as cysts was determined. Results All three bacterial isolates tested, associated, invaded, and survived inside A. castellanii trophozoites as well as A. castellanii cysts. However, E. aerogenes and E. coli exhibited significantly reduced association with and invasion of A. castellanii as compared with A. hydrophila (P < 0.01 using paired T-test, one tail distribution). In the long term survival assays, all three bacterial isolates tested remained viable inside A. castellanii trophozoites, while amoeba remained intact; however A. hydrophila exhibited higher survival inside amoebae (14.54 ± 3.3 bacteria:amoeba ratio) compared with E. aerogenes (3.96 ± 0.7 bacteria:amoeba ratio) and E. coli (5.85 ± 1.1 bacteria:amoeba ratio). A. hydrophila, E. coli, and E. aerogenes remained viable during the encystment process and exhibited higher levels of recovery from mature cysts (14.13 ± 0.89 A. hydrophila:amoeba ratio, 10.13 ± 1.17 E. aerogenes:amoeba ratio, and 11.95 ± 0.7 E. coli:amoeba ratio). Conclusions A. hydrophila and E. aerogenes also joined the ranks of other bacteria that could benefit from A. castellanii

  18. Role of sdhA and pfkA and catabolism of reduced carbon during colonization of cucumber roots by Enterobacter cloacae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Strain A-11 of the plant-beneficial bacterium Enterobacter cloacae was used as a tool to determine the importance of pfkA and catabolism of carbohydrates in exudate to the plant-associated activities of root colonization and suppression of damping-off. E . cloacae A-11 is a near-isogenic mutant of ...

  19. Mutation of a degS homologue in Enterobacter cloacae decreases colonization and biological control of damping-off caused by Pythium ultimum on cucumber

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have been using a mutational approach to determine how plant-beneficial bacteria, such as Enterobacter cloacae, deal with complex nutritional environments found in association with subterranean plant parts during colonization and disease suppression. E. cloacae C10, a mini-Tn5 Km mutant of E. cl...

  20. Dominance of IMP-4-Producing Enterobacter cloacae among Carbapenemase-Producing Enterobacteriaceae in Australia

    PubMed Central

    Townell, Nicola; Nimmo, Graeme R.; George, Narelle M.; Robson, Jennifer; Vohra, Renu; Davis, Louise; Heney, Claire; Paterson, David L.

    2015-01-01

    The prevalence of carbapenemase-producing Enterobacteriaceae (CPE) has been increasing worldwide. blaIMP has been reported to be the predominant carbapenemase-encoding gene within Enterobacteriaceae in Australia. However, there are limited data currently available on CPE from Queensland, Australia. A total of 58 CPE isolates were isolated between July 2009 and March 2014 from Queensland hospitals. The clonality of isolates was determined by Diversilab repetitive sequence-based PCR. The isolates were investigated for the resistance mechanisms carbapenemase, extended-spectrum β-lactamase, and AmpC β-lactamase and for aminoglycoside resistance and plasmid-mediated quinolone resistance genes by PCR. The plasmid types associated with carbapenemase-encoding genes were characterized. The majority of the CPE were Enterobacter cloacae (n = 29). The majority of Queensland CPE isolates were IMP producers and comprised 11 species (n = 48). Nine NDM-producing Enterobacteriaceae were identified. One NDM-producing Klebsiella pneumoniae isolate coproduced OXA-48. One K. pneumoniae isolate was an OXA-181 producer. The incidence of IMP producers increased significantly in 2013. blaIMP-4 was found in all IMP-producing isolates. blaTEM, qnrB, and aacA4 were common among IMP-4 producers. The HI2 (67%) and L/M (21%) replicons were associated with blaIMP-4. All HI2 plasmids were of sequence type 1 (ST1). All but one of the NDM producers possessed blaCTX-M-15. The 16S rRNA methylase genes found among NDM producers were armA, rmtB, rmtC, and rmtF. The substantial increase in the prevalence of CPE in Queensland has been associated mainly with the emergence E. cloacae strains possessing HI2 plasmids carrying blaIMP-4 over the past 2 years. The importation of NDM producers and/or OXA-48-like producers in patients also contributed to the increased emergence of CPE. PMID:25918153

  1. Draft Whole-Genome Sequence of VIM-1-Producing Multidrug-Resistant Enterobacter cloacae EC_38VIM1

    PubMed Central

    Villa, Jennifer; Viedma, Esther; Otero, Joaquín R.

    2013-01-01

    The VIM-1-producing multidrug-resistant strain Enterobacter cloacae was isolated from blood culture. The strain showed multiple resistances to clinically used antibiotics, including all β-lactams, fluoroquinolones, aminoglycosides, and sulfonamides. Sequence analysis showed the presence of 14 genes associated with resistance to antibiotics, including the metallo-β-lactamase VIM-1 gene, which was located in a class 1 integron. PMID:24009122

  2. Metal Accumulation and Vanadium-Induced Multidrug Resistance by Environmental Isolates of Escherichia hermannii and Enterobacter cloacae

    PubMed Central

    Hernández, Alicia; Mellado, Rafael P.; Martínez, José L.

    1998-01-01

    Contaminated soils from an oil refinery were screened for the presence of microorganisms capable of accumulating either nickel, vanadium, or both metals. Three strains of bacteria that belonged to the family Enterobacteriaceae were selected. Two of them were Escherichia hermannii strains, and outer membrane profile (OMP) analysis showed that they were similar to a strain of clinical origin; the other one was an Enterobacter cloacae strain that differed from clinical isolates. The selected bacteria accumulated both nickel and vanadium. Growth in the presence of vanadium induced multidrug resistance phenotypes in E. hermannii and E. cloacae. Incubation with this metal changed the OMP profile of E. hermannii but did not produce variations in the expression of the major OMPs of E. cloacae. PMID:9797283

  3. Genome Sequence of Enterobacter cloacae Strain SENG-6, a Bacterium Producing Histo-Blood Group Antigen-Like Substances That Can Bind with Human Noroviruses

    PubMed Central

    Amarasiri, Mohan; Hashiba, Satoshi; Yang, Peiyi; Okabe, Satoshi

    2016-01-01

    Enterobacter sp. strain SENG-6, isolated from healthy human feces, produces histo-blood group antigen (HBGA)-like substances that can bind with human noroviruses. Based on the genome sequence analysis, strain SENG-6 belongs to the species Enterobacter cloacae. The genome sequence of this strain should help identify genes associated with the production of HBGA-like substances. PMID:27563051

  4. Infections with VIM-1 Metallo-β-Lactamase-Producing Enterobacter cloacae and Their Correlation with Clinical Outcome▿

    PubMed Central

    Falcone, Marco; Mezzatesta, Maria Lina; Perilli, Mariagrazia; Forcella, Chiara; Giordano, Alessandra; Cafiso, Viviana; Amicosante, Gianfranco; Stefani, Stefania; Venditti, Mario

    2009-01-01

    The aim of this study was to ascertain the incidence and clinical significance of metallo-β-lactamases among Enterobacter strains isolated from patients with nosocomial infections. We prospectively collected data on patients with Enterobacter infection during a 13-month period. All of the strains were investigated for antibiotic susceptibility, the presence and expression of metallo-β-lactamases, and clonality. Of 29 infections (11 involving the urinary tract, 7 pneumonias, 3 skin/soft tissue infections, 3 intra-abdominal infections, 3 bacteremias, and 2 other infections), 7 (24%) were caused by Enterobacter cloacae strains harboring a blaVIM-1 gene associated or not with a blaSHV12 gene. Infections caused by VIM-1-producing strains were more frequently associated with a recent prior hospitalization (P = 0.006), cirrhosis (P = 0.03), relapse of infection (P < 0.001), and more prolonged duration of antibiotic therapy (P = 0.01) than were other infections. All of the isolates were susceptible to imipenem and meropenem and had blaVIM-1 preceded by a weak P1 promoter and inactivated P2 promoters. Most VIM-1-producing Enterobacter isolates belonged to a main clone, but four different clones were found. Multiclonal VIM-1-producing E. cloacae infections are difficult to diagnose due to an apparent susceptibility to various beta-lactams, including carbapenems, and are associated with a high relapse rate and a more prolonged duration of antibiotic therapy. PMID:19741074

  5. Long-term arsenic monitoring with an Enterobacter cloacae microbial fuel cell.

    PubMed

    Rasmussen, Michelle; Minteer, Shelley D

    2015-12-01

    A microbial fuel cell was constructed with biofilms of Enterobacter cloacae grown on the anode. Bioelectrocatalysis was observed when the biofilm was grown in media containing sucrose as the carbon source and methylene blue as the mediator. The presence of arsenic caused a decrease in bioelectrocatalytic current. Biofilm growth in the presence of arsenic resulted in lower power outputs whereas addition of arsenic showed no immediate result in power output due to the short term arsenic resistance of the bacteria and slow transport of arsenic across cellular membranes to metabolic enzymes. Calibration curves plotted from the maximum current and maximum power of power curves after growth show that this system is able to quantify both arsenate and arsenate with low detection limits (46 μM for arsenate and 4.4 μM for arsenite). This system could be implemented as a method for long-term monitoring of arsenic concentration in environments where arsenic contamination could occur and alter the metabolism of the organisms resulting in a decrease in power output of the self-powered sensor. PMID:25862430

  6. Biohydrogen and Bioethanol Production from Biodiesel-Based Glycerol by Enterobacter aerogenes in a Continuous Stir Tank Reactor

    PubMed Central

    Jitrwung, Rujira; Yargeau, Viviane

    2015-01-01

    Crude glycerol from the biodiesel manufacturing process is being produced in increasing quantities due to the expanding number of biodiesel plants. It has been previously shown that, in batch mode, semi-anaerobic fermentation of crude glycerol by Enterobacter aerogenes can produce biohydrogen and bioethanol simultaneously. The present study demonstrated the possible scaling-up of this process from small batches performed in small bottles to a 3.6-L continuous stir tank reactor (CSTR). Fresh feed rate, liquid recycling, pH, mixing speed, glycerol concentration, and waste recycling were optimized for biohydrogen and bioethanol production. Results confirmed that E. aerogenes uses small amounts of oxygen under semi-anaerobic conditions for growth before using oxygen from decomposable salts, mainly NH4NO3, under anaerobic condition to produce hydrogen and ethanol. The optimal conditions were determined to be 500 rpm, pH 6.4, 18.5 g/L crude glycerol (15 g/L glycerol) and 33% liquid recycling for a fresh feed rate of 0.44 mL/min. Using these optimized conditions, the process ran at a lower media cost than previous studies, was stable after 7 days without further inoculation and resulted in yields of 0.86 mol H2/mol glycerol and 0.75 mol ethanol/mole glycerol. PMID:25970750

  7. Biohydrogen and polyhydroxyalkanoate co-production by Enterobacter aerogenes and Rhodobacter sphaeroides from Calophyllum inophyllum oil cake.

    PubMed

    Arumugam, A; Sandhya, M; Ponnusami, V

    2014-07-01

    The feasibility of coupled biohydrogen and polyhydroxyalkanoate production by Enterobacter aerogenes and Rhodobacter sphaeroides using Calophyllum inophyllum oil cake was studied under dark and photo fermentation conditions. The utilization of a non-edible acidic oil cake (C. inophyllum), and exploitation of a modified minimal salt media led to reduction in the cost of media. Cost of fermentation is reduced by implementation of alternate dark-photo fermentative periods and through the use of a co-culture consisting of a dark fermentative (E. aerogenes) and a photo fermentative (R. sphaeroides) bacterium. The biohydrogen and polyhydroxyalkanoate produced were 7.95 L H2/L media and 10.73 g/L media, respectively, under alternate dark and photo fermentation and were 3.23 L H2/L media and 5.6g/L media, respectively under complete dark fermentation. The characteristics of the oil cake and alternate dark (16 h) and photo (8h) fermentative conditions were found to be supportive in producing high biohydrogen and polyhydroxyalkanoate (PHA) yield. PMID:24859207

  8. Biohydrogen and Bioethanol Production from Biodiesel-Based Glycerol by Enterobacter aerogenes in a Continuous Stir Tank Reactor.

    PubMed

    Jitrwung, Rujira; Yargeau, Viviane

    2015-01-01

    Crude glycerol from the biodiesel manufacturing process is being produced in increasing quantities due to the expanding number of biodiesel plants. It has been previously shown that, in batch mode, semi-anaerobic fermentation of crude glycerol by Enterobacter aerogenes can produce biohydrogen and bioethanol simultaneously. The present study demonstrated the possible scaling-up of this process from small batches performed in small bottles to a 3.6-L continuous stir tank reactor (CSTR). Fresh feed rate, liquid recycling, pH, mixing speed, glycerol concentration, and waste recycling were optimized for biohydrogen and bioethanol production. Results confirmed that E. aerogenes uses small amounts of oxygen under semi-anaerobic conditions for growth before using oxygen from decomposable salts, mainly NH4NO3, under anaerobic condition to produce hydrogen and ethanol. The optimal conditions were determined to be 500 rpm, pH 6.4, 18.5 g/L crude glycerol (15 g/L glycerol) and 33% liquid recycling for a fresh feed rate of 0.44 mL/min. Using these optimized conditions, the process ran at a lower media cost than previous studies, was stable after 7 days without further inoculation and resulted in yields of 0.86 mol H2/mol glycerol and 0.75 mol ethanol/mole glycerol. PMID:25970750

  9. Fluoroquinolone Resistance Mechanisms and population structure of Enterobacter cloacae non-susceptible to Ertapenem in North-Eastern France

    PubMed Central

    Guillard, Thomas; Cholley, Pascal; Limelette, Anne; Hocquet, Didier; Matton, Lucie; Guyeux, Christophe; Lebreil, Anne-Laure; Bajolet, Odile; Brasme, Lucien; Madoux, Janick; Vernet-Garnier, Véronique; Barbe, Coralie; Bertrand, Xavier; de Champs on behalf of CarbaFrEst Group, Christophe

    2015-01-01

    Fluoroquinolone (FQ) agents are a potential resort to treat infection due to Enterobacteriaceae producing extended spectrum β-lactamase and susceptible to FQ. In a context of increase of non-susceptibility to carbapenems among Enterobacteriaceae, we characterized FQ resistance mechanisms in 75 Enterobacter cloacae isolates non-susceptible to ertapenem in North-Eastern France in 2012 and describe the population structure by pulsed field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Among them, 14.7% (12/75) carried a carbapenemase-encoding gene. Except one isolate producing VIM-1, the carbapenemase-producing isolates carried the well-known IncL/M pOXA48a plasmid. Most of the isolates (59/75) harbored at least a FQ-R determinant. qnr genes were predominant (40%, 30/75). The MLST study revealed that E. cloacae isolates’ clonality was wide [24 different sequence types (STs)]. The more widespread STs were ST74, ST101, ST110, ST114, and ST133. Carbapenem MICs were higher for E. cloacae ST74 than for other E. cloacae isolates. Plasmid-mediated quinolone resistance determinants were more often observed in E. cloacae ST74 isolates. These findings showed that (i) pOXA-48a is spreading in North-Eastern France, (ii) qnr is preponderant in E. cloacae, (iii) E. cloacae comprised a large amount of lineages spreading in North-Eastern France, and (iv) FQ as an alternative to β-lactams to treat ertapenem non-susceptible Enterobacteriaceae are compromised. PMID:26557115

  10. Fatty acid competition as a mechanism by which Enterobacter cloacae suppresses Pythium ultimum sporangium germination and damping-off.

    PubMed

    van Dijk, K; Nelson, E B

    2000-12-01

    Interactions between plant-associated microorganisms play important roles in suppressing plant diseases and enhancing plant growth and development. While competition between plant-associated bacteria and plant pathogens has long been thought to be an important means of suppressing plant diseases microbiologically, unequivocal evidence supporting such a mechanism has been lacking. We present evidence here that competition for plant-derived unsaturated long-chain fatty acids between the biological control bacterium Enterobacter cloacae and the seed-rotting oomycete, Pythium ultimum, results in disease suppression. Since fatty acids from seeds and roots are required to elicit germination responses of P. ultimum, we generated mutants of E. cloacae to evaluate the role of E. cloacae fatty acid metabolism on the suppression of Pythium sporangium germination and subsequent plant infection. Two mutants of E. cloacae EcCT-501R3, Ec31 (fadB) and EcL1 (fadL), were reduced in beta-oxidation and fatty acid uptake, respectively. Both strains failed to metabolize linoleic acid, to inactivate the germination-stimulating activity of cottonseed exudate and linoleic acid, and to suppress Pythium seed rot in cotton seedling bioassays. Subclones containing fadBA or fadL complemented each of these phenotypes in Ec31 and EcL1, respectively. These data provide strong evidence for a competitive exclusion mechanism for the biological control of P. ultimum-incited seed infections by E. cloacae where E. cloacae prevents the germination of P. ultimum sporangia by the efficient metabolism of fatty acid components of seed exudate and thus prevents seed infections. PMID:11097912

  11. Complex Regulation Pathways of AmpC-Mediated β-Lactam Resistance in Enterobacter cloacae Complex

    PubMed Central

    Guérin, François; Isnard, Christophe; Giard, Jean Christophe

    2015-01-01

    Enterobacter cloacae complex (ECC), an opportunistic pathogen causing numerous infections in hospitalized patients worldwide, is able to resist β-lactams mainly by producing the AmpC β-lactamase enzyme. AmpC expression is highly inducible in the presence of some β-lactams, but the underlying genetic regulation, which is intricately linked to peptidoglycan recycling, is still poorly understood. In this study, we constructed different mutant strains that were affected in genes encoding enzymes suspected to be involved in this pathway. As expected, the inactivation of ampC, ampR (which encodes the regulator protein of ampC), and ampG (encoding a permease) abolished β-lactam resistance. Reverse transcription-quantitative PCR (qRT-PCR) experiments combined with phenotypic studies showed that cefotaxime (at high concentrations) and cefoxitin induced the expression of ampC in different ways: one involving NagZ (a N-acetyl-β-d-glucosaminidase) and another independent of NagZ. Unlike the model established for Pseudomonas aeruginosa, inactivation of DacB (also known as PBP4) was not responsible for a constitutive ampC overexpression in ECC, whereas it caused AmpC-mediated high-level β-lactam resistance, suggesting a post-transcriptional regulation mechanism. Global transcriptomic analysis by transcriptome sequencing (RNA-seq) of a dacB deletion mutant confirmed these results. Lastly, analysis of 37 ECC clinical isolates showed that amino acid changes in the AmpD sequence were likely the most crucial event involved in the development of high-level β-lactam resistance in vivo as opposed to P. aeruginosa where dacB mutations have been commonly found. These findings bring new elements for a better understanding of β-lactam resistance in ECC, which is essential for the identification of novel potential drug targets. PMID:26438498

  12. Epidemiology of Extended-Spectrum β-Lactamase-Producing Enterobacter Isolates in a Spanish Hospital during a 12-Year Period

    PubMed Central

    Cantón, Rafael; Oliver, Antonio; Coque, Teresa M.; Varela, María del Carmen; Pérez-Díaz, José Claudio; Baquero, Fernando

    2002-01-01

    Fifteen Enterobacter clinical isolates (11 Enterobacter cloacae isolates, 3 Enterobacter aerogenes isolates, and 1 Enterobacter gergoviae isolate), representing 0.4% of all Enterobacter isolates recovered in our hospital from 1989 to 2000, were suspected of harboring an extended-spectrum β-lactamase (ESBL). These isolates were recovered from 14 different patients. ESBLs were transferred by conjugation into an Escherichia coli recipient strain. Pulsed-field gel electrophoresis (PFGE) revealed a single clone of E. aerogenes and six different clones of E. cloacae. Four of these E. cloacae clonal types were represented by only one isolate each, but the other two were represented by three and four isolates, respectively. Isoelectric focusing, susceptibility phenotyping, PCR analysis, and sequencing demonstrated the presence of three different ESBLs. The most frequent was the recently characterized CTX-M-10 ESBL, which was found in the E. gergoviae isolate and in all but one of the E. cloacae isolates. The remaining E. cloacae isolate harbored a TEM-27 ESBL, and the three E. aerogenes isolates harbored a TEM-24 ESBL. PFGE revealed that our E. aerogenes strain was indistinguishable from the French TEM-24-producing E. aerogenes endemic clone. Although a low prevalence of ESBL-producing Enterobacter isolates was found in our institution over a 12-year period, a diversity of nonepidemic E. cloacae clones was detected, as was the persistence of the CTX-M-10 β-lactamase. The presence of the TEM-24-producing E. aerogenes French clone in our institution also demonstrates the intercountry dissemination of ESBL-producing isolates. PMID:11923338

  13. Characterization of the plant growth promoting bacterium, Enterobacter cloacae MSR1, isolated from roots of non-nodulating Medicago sativa

    PubMed Central

    Khalifa, Ashraf Y.Z.; Alsyeeh, Abdel-Moneium; Almalki, Mohammed A.; Saleh, Farag A.

    2015-01-01

    The aim of the present study was to characterize the endophytic bacterial strain designated MSR1 that was isolated from inside the non-nodulating roots of Medicago sativa after surface-sterilization. MSR1 was identified as Enterobacter cloacae using both 16S rDNA gene sequence analysis and API20E biochemical identification system (Biomerieux, France). Furthermore, this bacterium was characterized using API50CH kit (Biomerieux, France) and tested for antibacterial activities against some food borne pathogens. The results showed that E. cloacae consumed certain carbohydrates such as glycerol, d-xylose, d-maltose and esculin melibiose as a sole carbon source and certain amino acids such as arginine, tryptophan ornithine as nitrogen source. Furthermore, MSR1 possessed multiple plant-growth promoting characteristics; phosphate solubility, production of phytohormones acetoin and bioactive compounds. Inoculation of Pisum sativum with MSR1 significantly improved the growth parameters (the length and dry weight) of this economically important grain legume compared to the non-treated plants. To our knowledge, this is the first report addressing E. cloacae which exist in roots of alfalfa growing in Al-Ahsaa region. The results confirmed that E. cloacae exhibited traits for plant growth promoting and could be developed as an eco-friendly biofertilizer for P. sativum and probably for other important plant species in future. PMID:26858542

  14. Characterization of the plant growth promoting bacterium, Enterobacter cloacae MSR1, isolated from roots of non-nodulating Medicago sativa.

    PubMed

    Khalifa, Ashraf Y Z; Alsyeeh, Abdel-Moneium; Almalki, Mohammed A; Saleh, Farag A

    2016-01-01

    The aim of the present study was to characterize the endophytic bacterial strain designated MSR1 that was isolated from inside the non-nodulating roots of Medicago sativa after surface-sterilization. MSR1 was identified as Enterobacter cloacae using both 16S rDNA gene sequence analysis and API20E biochemical identification system (Biomerieux, France). Furthermore, this bacterium was characterized using API50CH kit (Biomerieux, France) and tested for antibacterial activities against some food borne pathogens. The results showed that E. cloacae consumed certain carbohydrates such as glycerol, d-xylose, d-maltose and esculin melibiose as a sole carbon source and certain amino acids such as arginine, tryptophan ornithine as nitrogen source. Furthermore, MSR1 possessed multiple plant-growth promoting characteristics; phosphate solubility, production of phytohormones acetoin and bioactive compounds. Inoculation of Pisum sativum with MSR1 significantly improved the growth parameters (the length and dry weight) of this economically important grain legume compared to the non-treated plants. To our knowledge, this is the first report addressing E. cloacae which exist in roots of alfalfa growing in Al-Ahsaa region. The results confirmed that E. cloacae exhibited traits for plant growth promoting and could be developed as an eco-friendly biofertilizer for P. sativum and probably for other important plant species in future. PMID:26858542

  15. Aerobic degradation of 2,4,6-trinitrotoluene by Enterobacter cloacae PB2 and by pentaerythritol tetranitrate reductase

    SciTech Connect

    French, C.E.; Bruce, N.C.; Nicklin, S.

    1998-08-01

    Enterobacter cloacae PB2 was originally isolated on the basis of its ability to utilize nitrate esters, such as pentaerythritol tetranitrate (PETN) and glycerol trinitrate, as the sole nitrogen source for growth. The enzyme responsible is an NADPH-dependent reductase designated PETN reductase. E. cloacae PB2 was found to be capable of slow aerobic growth with 2,4,6-trinitrotoluene (TNT) as the sole nitrogen source. Dinitrotoluenes were not produced and could not be used as nitrogen sources. Purified PETN reductase was found to reduce TNT to its hydride-Meisenheimer complex, which was further reduced to the dihydride-Meisenheimer complex. Purified PETN reductase and recombinant Escherichia coli expressing PETN reductase were able to liberate nitrogen as nitrite from TNT. The ability to remove nitrogen from TNT suggests that PB2 or recombinant organisms expressing PETN reductase may be useful for bioremediation of TNT-contaminated soil and water.

  16. Biotransformation of Ferulic acid to 4-Vinylguaiacol by Enterobacter soli and E. aerogenes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated the conversion of ferulic acid to 4-vinylguaiacol (4-VG), vanillin, vanillyl alcohol and vanillic acid by five Enterobacter strains. These high-value chemicals are usually synthesized using chemical methods but biological synthesis adds value. Ferulic acid, a relatively inexpensive...

  17. Characterization of an Enterobacter cloacae Strain Producing both KPC and NDM Carbapenemases by Whole-Genome Sequencing

    PubMed Central

    Wu, Wenjing; Feng, Yu; Carattoli, Alessandra

    2015-01-01

    A carbapenem-resistant Enterobacter cloacae strain, WCHECl-14653, causing a fatal bloodstream infection, was characterized by genome sequencing and conjugation experiments. The strain carried two carbapenemase genes, blaNDM-1 and blaKPC-2, on separate IncF plasmids. The coexistence of blaNDM-1 and blaKPC-2 conferred slightly higher-level carbapenem resistance compared with that of blaNDM-1 or blaKPC-2 alone, and the coexistence of two IncF plasmids may generate new platforms for spreading carbapenemase genes. PMID:26248381

  18. Mutational analysis of the hyc-operon determining the relationship between hydrogenase-3 and NADH pathway in Enterobacter aerogenes.

    PubMed

    Pi, Jian; Jawed, Muhammad; Wang, Jun; Xu, Li; Yan, Yunjun

    2016-01-01

    In this study, the hydrogenase-3 gene cluster (hycDEFGH) was isolated and identified from Enterobacter aerogenes CCTCC AB91102. All gene products were highly homologous to the reported bacterial hydrogenase-3 (Hyd-3) proteins. The genes hycE, hycF, hycG encoding the subunits of hydrogenase-3 were targeted for genetic knockout to inhibit the FHL hydrogen production pathway via the Red recombination system, generating three mutant strains AB91102-E (ΔhycE), AB91102-F (ΔhycF) and AB91102-G (ΔhycG). Deletion of the three genes affected the integrity of hydrogenase-3. The hydrogen production experiments with the mutant strains showed that no hydrogen was detected compared with the wild type (0.886 mol/mol glucose), demonstrating that knocking out any of the three genes could inhibit NADH hydrogen production pathway. Meanwhile, the metabolites of the mutant strains were significantly changed in comparison with the wild type, indicating corresponding changes in metabolic flux by mutation. Additionally, the activity of NADH-mediated hydrogenase was found to be nil in the mutant strains. The chemostat experiments showed that the NADH/NAD(+) ratio of the mutant strains increased nearly 1.4-fold compared with the wild type. The NADH-mediated hydrogenase activity and NADH/NAD(+) ratio analysis both suggested that NADH pathway required the involvement of the electron transport chain of hydrogenase-3. PMID:26672442

  19. Characterization of the genes of the 2,3-butanediol operons from Klebsiella terrigena and Enterobacter aerogenes.

    PubMed Central

    Blomqvist, K; Nikkola, M; Lehtovaara, P; Suihko, M L; Airaksinen, U; Stråby, K B; Knowles, J K; Penttilä, M E

    1993-01-01

    The genes involved in the 2,3-butanediol pathway coding for alpha-acetolactate decarboxylase, alpha-acetolactate synthase (alpha-ALS), and acetoin (diacetyl) reductase were isolated from Klebsiella terrigena and shown to be located in one operon. This operon was also shown to exist in Enterobacter aerogenes. The budA gene, coding for alpha-acetolactate decarboxylase, gives in both organisms a protein of 259 amino acids. The amino acid similarity between these proteins is 87%. The K. terrigena genes budB and budC, coding for alpha-ALS and acetoin reductase, respectively, were sequenced. The 559-amino-acid-long alpha-ALS enzyme shows similarities to the large subunits of the Escherichia coli anabolic alpha-ALS enzymes encoded by the genes ilvB, ilvG, and ilvI. The K. terrigena alpha-ALS is also shown to complement an anabolic alpha-ALS-deficient E. coli strain for valine synthesis. The 243-amino-acid-long acetoin reductase has the consensus amino acid sequence for the insect-type alcohol dehydrogenase/ribitol dehydrogenase family and has extensive similarities with the N-terminal and internal regions of three known dehydrogenases and one oxidoreductase. Images PMID:8444801

  20. Phenolic compounds: Strong inhibitors derived from lignocellulosic hydrolysate for 2,3-butanediol production by Enterobacter aerogenes.

    PubMed

    Lee, Sang Jun; Lee, Ju Hun; Yang, Xiaoguang; Kim, Sung Bong; Lee, Ja Hyun; Yoo, Hah Young; Park, Chulhwan; Kim, Seung Wook

    2015-12-01

    Lignocellulosic biomass are attractive feedstocks for 2,3-butanediol production due to their abundant supply and low price. During the hydrolysis of lignocellulosic biomass, various byproducts are formed and their effects on 2,3-butanediol production were not sufficiently studied compared to ethanol production. Therefore, the effects of compounds derived from lignocellulosic biomass (weak acids, furan derivatives and phenolics) on the cell growth, the 2,3-butanediol production and the enzymes activity involved in 2,3-butanediol production were evaluated using Enterobacter aerogenes ATCC 29007. The phenolic compounds showed the most toxic effects on cell growth, 2,3-butanediol production and enzyme activity, followed by furan derivatives and weak acids. The significant effects were not observed in the presence of acetic acid and formic acid. Also, feasibility of 2,3-butanediol production from lignocellulosic biomass was evaluated using Miscanthus as a feedstock. In the fermentation of Miscanthus hydrolysate, 11.00 g/L of 2,3-butanediol was obtained from 34.62 g/L of reducing sugar. However, 2,3-butanediol was not produced when the concentration of total phenolic compounds in the hydrolysate increased to more than 1.5 g/L. The present study provides useful information to develop strategies for biological production of 2,3-butanediol and to establish biorefinery for biochemicals from lignocellulosic biomass. PMID:26479290

  1. High-yield production of hydrogen by Enterobacter aerogenes mutants with decreased alpha-acetolactate synthase activity.

    PubMed

    Ito, Takeshi; Nakashimada, Yutaka; Kakizono, Toshihide; Nishio, Naomichi

    2004-01-01

    To enhance hydrogen (H2) production from glucose by Enterobacter aerogenes HU-101, two mutants, strains VP-1 and VP-2, with decreased alpha-acetolactate synthase activity, were isolated using the Voges-Proskauer (VP) test. In pH-uncontrolled batch culture, both mutants showed a lower 2,3-butanediol yield for the glucose consumed than that shown by the wild-type strain, although glucose remained in the medium after 12 h of culture. In the same cultures, compared to the H2 yield of 0.80 mol/mol-glucose of the wild-type strain, strain VP-1 showed a high H2 yield of 1.8 mol/mol-glucose with decreased lactate and increased succinate yields, while strain VP-2 showed an H2 yield of 1.0 mol/mol-glucose with an increased lactate yield. Increasing the phosphate buffer concentration, which contributes to maintaining the pH in the medium, increased the glucose consumption by both strains. However, in a pH-controlled batch culture at neutral pH, the H2 yield of strain VP-1 was decreased to 1.2 mol/mol-glucose due to the accumulation of formate, an intermediate of the H2-producing pathway, with the yield of H2 plus formate being 1.7 mol/mol-glucose. PMID:16233620

  2. The curli biogenesis genes expression level is unassociated with Enterobacter cloacae hsp60 clusters and PFGE genotypes.

    PubMed

    Akbari, Majid; Bakhshi, Bita; Najar-Peerayeh, Shahin; Behmanesh, Mehrdad

    2016-09-01

    The objective of this study was to determine the correlation between Enterobacter cloacae complex subspecies and clusters involved in UTI infections and specific pulsotypes, and to assess the contribution of major curli biogenesis genes (csgD, csgA) expression level to pathogenesis of clusters and genotypes. Based on the PFGE analysis, 37 different profiles were observed among which 8 profiles were common types. Real time PCR of csgD and csgA genes of 50 E. cloacae complex in relation to PFGE and hsp60 genotypes showed that all the genetic clusters are not equally involved in pathogenesis of urinary tract infections. It was elucidated in this study that isolates with common PFGE genotypes belonged to identical hsp60 clusters, and the foremost clusters (VI, III, and V) mainly comprised within PFGE common types. In our study, no significant correlation was detected between the specific hsp60 clusters or PFGE genotypes and the expression level of csgD and csgA genes (P-value > 0.05). This is the first study describing that unequivalent contribution of E. cloacae genotypes and clusters in pathogenesis of UTI, is not owing to varied curli biogenesis expression potential. The PFGE genotyping showed more discriminatory power than hsp60 genotyping for epidemiological studies and source tracking purpose. PMID:27354208

  3. ANTIFUNGAL AND SPROUT REGULATORY BIOACTIVITIES OF PHENYLACETIC ACID, INDOLE-3-ACETIC ACID, AND TYROSOL ISOLATED FROM THE POTATO DRY ROT SUPPRESSIVE BACTERIUM ENTEROBACTER CLOACAE S11:T:07

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enterobacter cloacae S11:T:07 (NRRL B-21050) is a promising biological control agent which has significantly reduced both fungal dry rot disease and sprouting in lab and pilot potato storages. The metabolites phenylacetic acid (PAA), indole-3-acetic acid (IAA), and tyrosol (TSL) were isolated from ...

  4. Physicochemical, nutritional, and microbial quality of fresh-cut and frozen papaya prepared from cultivars with varying resistance to internal yellowing disease (Enterobacter cloacae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quality, nutritional, and microbial analyses were completed for fresh-cut and frozen papaya cubes prepared from cultivars with varying resistance to internal yellowing disease, caused by the bacterium Enterobacter cloacae. In general, fresh-cut and frozen papaya retained nutritional and microbial qu...

  5. Isolation of Enterobacter aerogenes carrying blaTEM-1 and blaKPC-3 genes recovered from a hospital Intensive Care Unit.

    PubMed

    Pulcrano, Giovanna; Pignanelli, Salvatore; Vollaro, Adriana; Esposito, Matilde; Iula, Vita Dora; Roscetto, Emanuela; Soriano, Amata Amy; Catania, Maria Rosaria

    2016-06-01

    Enterobacter aerogenes has recently emerged as an important hospital pathogen. In this study, we showed the emergence of E. aerogenes isolates carrying the blaKPC gene in patients colonized by carbapenem-resistant Klebsiella pneumoniae strains. Two multiresistant E. aerogenes isolates were recovered from bronchial aspirates of two patients hospitalized in the Intensive Care Unit at the "Santa Maria della Scaletta" Hospital, Imola. The antimicrobial susceptibility test showed the high resistance to carbapenems and double-disk synergy test confirmed the phenotype of KPC and AmpC production. Other investigation revealed that ESBL and blaKPC genes were carried on the conjugative pKpQIL plasmid. This is a relevant report in Italy that describes a nosocomial infection due to the production of KPC beta-lactamases by an E. aerogenes isolate in patients previously colonized by K. pneumoniae carbapenem-resistant. In conclusion, it's necessary a continuous monitoring of multidrug-resistant strains for the detection of any KPC-producing bacteria that could expand the circulation of carbapenem-resistant pathogens. PMID:27004836

  6. Effects of eliminating pyruvate node pathways and of coexpression of heterogeneous carboxylation enzymes on succinate production by Enterobacter aerogenes.

    PubMed

    Tajima, Yoshinori; Yamamoto, Yoko; Fukui, Keita; Nishio, Yousuke; Hashiguchi, Kenichi; Usuda, Yoshihiro; Sode, Koji

    2015-02-01

    Lowering the pH in bacterium-based succinate fermentation is considered a feasible approach to reduce total production costs. Newly isolated Enterobacter aerogenes strain AJ110637, a rapid carbon source assimilator under weakly acidic (pH 5.0) conditions, was selected as a platform for succinate production. Our previous work showed that the ΔadhE/PCK strain, developed from AJ110637 with inactivated ethanol dehydrogenase and introduced Actinobacillus succinogenes phosphoenolpyruvate carboxykinase (PCK), generated succinate as a major product of anaerobic mixed-acid fermentation from glucose under weakly acidic conditions (pH <6.2). To further improve the production of succinate by the ΔadhE/PCK strain, metabolically engineered strains were designed based on the elimination of pathways that produced undesirable products and the introduction of two carboxylation pathways from phosphoenolpyruvate and pyruvate to oxaloacetate. The highest production of succinate was observed with strain ES04/PCK+PYC, which had inactivated ethanol, lactate, acetate, and 2,3-butanediol pathways and coexpressed PCK and Corynebacterium glutamicum pyruvate carboxylase (PYC). This strain produced succinate from glucose with over 70% yield (gram per gram) without any measurable formation of ethanol, lactate, or 2,3-butanediol under weakly acidic conditions. The impact of lowering the pH from 7.0 to 5.5 on succinate production in this strain was evaluated under pH-controlled batch culture conditions and showed that the lower pH decreased the succinate titer but increased its yield. These findings can be applied to identify additional engineering targets to increase succinate production. PMID:25416770

  7. In Vivo Evolution of Bacterial Resistance in Two Cases of Enterobacter aerogenes Infections during Treatment with Imipenem

    PubMed Central

    Santini, Sébastien; Pinet, Elizabeth; Claverie, Jean-Michel; Davin-Régli, Anne-Véronique; Pagès, Jean-Marie; Masi, Muriel

    2015-01-01

    Infections caused by multidrug resistant (MDR) bacteria are a major concern worldwide. Changes in membrane permeability, including decreased influx and/or increased efflux of antibiotics, are known as key contributors of bacterial MDR. Therefore, it is of critical importance to understand molecular mechanisms that link membrane permeability to MDR in order to design new antimicrobial strategies. In this work, we describe genotype-phenotype correlations in Enterobacter aerogenes, a clinically problematic and antibiotic resistant bacterium. To do this, series of clinical isolates have been periodically collected from two patients during chemotherapy with imipenem. The isolates exhibited different levels of resistance towards multiple classes of antibiotics, consistently with the presence or the absence of porins and efflux pumps. Transport assays were used to characterize membrane permeability defects. Simultaneous genome-wide analysis allowed the identification of putative mutations responsible for MDR. The genome of the imipenem-susceptible isolate G7 was sequenced to closure and used as a reference for comparative genomics. This approach uncovered several loci that were specifically mutated in MDR isolates and whose products are known to control membrane permeability. These were omp35 and omp36, encoding the two major porins; rob, encoding a global AraC-type transcriptional activator; cpxA, phoQ and pmrB, encoding sensor kinases of the CpxRA, PhoPQ and PmrAB two-component regulatory systems, respectively. This report provides a comprehensive analysis of membrane alterations relative to mutational steps in the evolution of MDR of a recognized nosocomial pathogen. PMID:26398358

  8. Optimization of 2,3-butanediol production by Enterobacter cloacae in simultaneous saccharification and fermentation of corncob residue.

    PubMed

    Zhang, Cui-Ying; Peng, Xiao-Pei; Li, Wei; Guo, Xue-Wu; Xiao, Dong-Guang

    2014-01-01

    Corncob residue, a waste in xylose or xylitol production, was utilized to produce 2,3-butanediol (2,3-BD) via simultaneous saccharification and fermentation (SSF). This study developed the optimal conditions for production of 2,3-BD by using a heat-resistant strain, Enterobacter cloacae UV4, to perform SSF of the corncob residue. Urea, lactic acid, sodium citrate, and MgSO4 , selected by the Plackett-Burman experiment, were determined to be significant independent variables to conduct the response surface experiment. With the optimized medium, a total production of 28.923 g/L for 2,3-BD and acetoin (BA) was obtained at 60 H. Furthermore, 43.162 g/L of BA production and 0.553 g/L/H of productivity were obtained by fed-batch SSF, which was 0.424 g diol/g consumed corncob residue. The results suggest that the waste corncob residue could be used as an available substrate for the production of 2,3-BD by E. cloacae UV4, as well as a potential resource to improve the economics of microbial compound production. PMID:24750278

  9. Dissemination of multiresistant Enterobacter cloacae isolates producing OXA-48 and CTX-M-15 in a Spanish hospital.

    PubMed

    Fernández, Javier; Montero, Ignacio; Martínez, Óscar; Fleites, Ana; Poirel, Laurent; Nordmann, Patrice; Rodicio, M Rosario

    2015-10-01

    Twenty-one multiresistant Enterobacter cloacae isolates producing OXA-48 (n=10), CTX-M-15 (n=7) or both (n=4) β-lactamases were detected in a Spanish hospital during a 1-year period (June 2013 to June 2014). The isolates were also resistant to non-β-lactam antimicrobials, further complicating the therapeutic options. Genotyping of the isolates identified two major clones (ST74 and ST66) that caused prolonged outbreaks in different buildings of the hospital as well as some sporadic isolates (ST78, ST45 and ST295). Isolates belonging to clone 1 (n=7) were carbapenem-resistant and carried the bla(OXA-48) gene on a conjugative IncL/M plasmid of ca. 65 kb. Clone 2 isolates (n=11) were resistant to cefepime and harboured the bla(CTX-M-15) gene on an ca. 150-kb, non-conjugative plasmid of the IncF group, co-harbouring the qnrB and aac(6')-Ib-cr genes encoding quinolone resistance. Four clone 2 isolates were also resistant to carbapenems owing to the co-production of OXA-48. Most of the isolates were recovered from critically ill patients and were admitted to intensive care units; a single patient was transferred from another Spanish hospital. Intrahospital and interhospital dissemination of multiresistant E. cloacae isolates is of major clinical concern as it could lead to endemic nosocomial situations. PMID:26307466

  10. Reduced carbon utilization, competitive colonization of the spermosphere, and disease suppression by Enterobacter cloacae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    De Wit Replacement series and disease suppression experiments with a collection of nutritional mutants of E. cloacae 501R3 are being used to determine the role of reduced carbon compounds found in seed exudate during beneficial activities by this bacterium. Mutants A-11, M2, and M43 contain single ...

  11. Tuberculose de l’épaule masquée par une infection concomitante à enterobacter cloacae: à propos d'un cas

    PubMed Central

    Gbané-Koné, Mariam; Koné, Samba; Ouali, Boubacar; Djaha, Kouassi Jean-Mermoz; Diomandé, Mohamed; Eti, Edmond; Touré, Stanislas André; Kouakou, N'zué Marcel

    2015-01-01

    La tuberculose de l’épaule est une localisation rare de même que l'arthrite septique à Enterobacter cloacae, les auteurs rapportent un cas d'ostéoarthrite de l’épaule à Bacille de Koch et à E. Cloacae chez une patiente de 36 ans avec un terrain particulier (drépanocytose SC et infection à VIH). Le diagnostic a été possible grâce aux prélèvements chirurgicaux effectués lors de l'arthrotomie PMID:26401203

  12. Effect of aerosol immunization with RE 595 Salmonella minnesota on lung bactericidal activity against Serratia marcescens, Enterobacter cloacae, and Pseudomonas aeruginosa.

    PubMed

    LaForce, F M

    1977-08-01

    Intrapulmonary bactericidal activity was measured after mice were given 3 weekly aerosol exposures to acid-hydrolyzed Re 595 Salmonella minnesota. Ten days after their last immunization, mice were challenged with aerolized Serratia marcescens, Enterobacter cloacae, or Pseudomonas aeruginosa. Quantitative bacterial counts in ground lung were obtained immediately after exposure and again 4 hours later. Enhanced bactericidal activity against Serratia marcescens and Enterobacter cloacae was seen in immunized animals, whereas no difference with Pseudomonas aeruginosa was noted. In separate studies, immunization with Serratia marcescens yielded a similar enhancement of lung bactericidal activity. Mucociliary transport, as measured by disappearance of aerosolized Serratia marcescens labeled with phosphorus-32, was identical for both immunized and control animals. Using a standardized in vitro mouse alveolar macrophage phagocytic system, lung washes from animals immunized with Re 595 Salmonella minnesota had significant opsonic activity for Serratia marcescens but not for Pseudomonas aeruginosa. PMID:407823

  13. Genome Sequence of Enterobacter cloacae subsp. dissolvens SDM, an Efficient Biomass-Utilizing Producer of Platform Chemical 2,3-Butanediol

    PubMed Central

    Xu, Youqiang; Wang, Ailong; Tao, Fei; Su, Fei; Tang, Hongzhi

    2012-01-01

    Enterobacter cloacae subsp. dissolvens SDM has an extraordinary characteristic of biomass utilization for 2,3-butanediol production. Here we present a 4.9-Mb assembly of its genome. The key genes for regulation and metabolism of 2,3-butanediol production were annotated, which could provide further insights into the molecular mechanism of high-yield production of 2,3-butanediol. PMID:22275097

  14. Mutation of a degS homologue in Enterobacter cloacae decreases colonization and biological control of damping-off on cucumber.

    PubMed

    Roberts, Daniel P; Lohrke, Scott M; McKenna, Laurie; Lakshman, Dilip K; Kong, Hyesuk; Lydon, John

    2011-02-01

    We have been using mutagenesis to determine how biocontrol bacteria such as Enterobacter cloacae 501R3 deal with complex nutritional environments found in association with plants. E. cloacae C10, a mutant of 501R3 with a transposon insertion in degS, was diminished in growth on synthetic cucumber root exudate (SRE), colonization of cucumber seed and roots, and control of damping-off of cucumber caused by Pythium ultimum. DegS, a periplasmic serine protease in the closely related bacterium Escherichia coli K12, is required for the RpoE-mediated stress response. C10 containing wild-type degS from 501R3 or from E. coli K12 on pBeloBAC11 was significantly increased in growth on SRE, colonization of cucumber roots, and control of P. ultimum relative to C10 containing pBeloBAC11 alone. C10 and 501R3 were similar in sensitivity to acidic conditions, plant-derived phenolic compounds, oxidative stress caused by hydrogen peroxide, dessication, and high osmoticum; stress conditions potentially associated with plants. This study demonstrates a role for degS in the spermosphere and rhizosphere during colonization and disease control by Enterobacter cloacae. This study implicates, for the first time, the involvement of DegS and, by extension, the RpoE-mediated stress response, in reducing stress on E. cloacae resulting from the complex nutritional environments in the spermosphere and rhizosphere. PMID:20942652

  15. Genomic Characterization of Enterobacter cloacae Isolates from China That Coproduce KPC-3 and NDM-1 Carbapenemases.

    PubMed

    Du, Hong; Chen, Liang; Chavda, Kalyan D; Pandey, Ruchi; Zhang, Haifang; Xie, Xiaofang; Tang, Yi-Wei; Kreiswirth, Barry N

    2016-04-01

    Here, we report twoEnterobacter cloacaesequence type 231 isolates coproducing KPC-3 and NDM-1 that have caused lethal infections in a tertiary hospital in China. TheblaNDM-1-harboring plasmids carry IncA/C2and IncR replicons, showing a mosaic plasmid structure, and theblaNDM-1is harbored on a novel class I integron-like element.blaKPC-3is located on a Tn3-ΔblaTEM-1-blaKPC-3-ΔTn1722element, flanked by two 9-bp direct-repeat sequences and harbored on an IncX6 plasmid. PMID:26787700

  16. Efficient 2,3-Butanediol Production from Cassava Powder by a Crop-Biomass-Utilizer, Enterobacter cloacae subsp. dissolvens SDM

    PubMed Central

    Ma, Cuiqing; Gao, Chao; Li, Lixiang; Wang, Yu; Tao, Fei; Xu, Ping

    2012-01-01

    Background 2,3-Butanediol (BD) is considered as one of the key platform chemicals used in a variety of industrial applications. It is crucial to find an efficient sugar-utilizing strain and feasible carbon source for the economical production of BD. Methodology/Principal Findings Efficient BD production by a newly isolated Enterobacter cloacae subsp. dissolvens SDM was studied using crop-biomass cassava powder as substrate. The culture conditions and fermentation medium for BD production were optimized. Under the optimal conditions, 78.3 g l−1 of BD was produced after 24 h in simultaneous saccharification and fermentation (SSF), with a yield of 0.42 g BD g−1 cassava powder and a specific productivity of 3.3 g l−1 h−1. A higher BD concentration (93.9 g l−1) was produced after 47 h in fed-batch SSF. Conclusions/Significance The results suggest that strain SDM is a good candidate for the BD production, and cassava powder could be used as an alternative substrate for the efficient production of BD. PMID:22792324

  17. Genetic and Biochemical Characterization of FRI-1, a Carbapenem-Hydrolyzing Class A β-Lactamase from Enterobacter cloacae

    PubMed Central

    Dortet, Laurent; Poirel, Laurent; Abbas, Samia; Oueslati, Saoussen

    2015-01-01

    An Enterobacter cloacae isolate was recovered from a rectal swab from a patient hospitalized in France with previous travel to Switzerland. It was resistant to penicillins, narrow- and broad-spectrum cephalosporins, aztreonam, and carbapenems but remained susceptible to expanded-spectrum cephalosporins. Whereas PCR-based identification of the most common carbapenemase genes failed, the biochemical Carba NP test II identified an Ambler class A carbapenemase. Cloning experiments followed by sequencing identified a gene encoding a totally novel class A carbapenemase, FRI-1, sharing 51 to 55% amino acid sequence identity with the closest carbapenemase sequences. However, it shared conserved residues as a source of carbapenemase activity. Purified β-lactamase FRI-1 hydrolyzed penicillins, aztreonam, and carbapenems but spared expanded-spectrum cephalosporins. The 50% inhibitory concentrations (IC50s) of clavulanic acid and tazobactam were 10-fold higher than those found for Klebsiella pneumoniae carbapenemase (KPC), IMI, and SME, leading to lower sensitivity of FRI-1 activity to β-lactamase inhibitors. The blaFRI-1 gene was located on a ca. 110-kb untypeable, transferable, and non-self-conjugative plasmid. A putative LysR family regulator-encoding gene at the 5′ end of the β-lactamase gene was identified, leading to inducible expression of the blaFRI-1 gene. PMID:26392482

  18. Genetic and Biochemical Characterization of FRI-1, a Carbapenem-Hydrolyzing Class A β-Lactamase from Enterobacter cloacae.

    PubMed

    Dortet, Laurent; Poirel, Laurent; Abbas, Samia; Oueslati, Saoussen; Nordmann, Patrice

    2015-12-01

    An Enterobacter cloacae isolate was recovered from a rectal swab from a patient hospitalized in France with previous travel to Switzerland. It was resistant to penicillins, narrow- and broad-spectrum cephalosporins, aztreonam, and carbapenems but remained susceptible to expanded-spectrum cephalosporins. Whereas PCR-based identification of the most common carbapenemase genes failed, the biochemical Carba NP test II identified an Ambler class A carbapenemase. Cloning experiments followed by sequencing identified a gene encoding a totally novel class A carbapenemase, FRI-1, sharing 51 to 55% amino acid sequence identity with the closest carbapenemase sequences. However, it shared conserved residues as a source of carbapenemase activity. Purified β-lactamase FRI-1 hydrolyzed penicillins, aztreonam, and carbapenems but spared expanded-spectrum cephalosporins. The 50% inhibitory concentrations (IC50s) of clavulanic acid and tazobactam were 10-fold higher than those found for Klebsiella pneumoniae carbapenemase (KPC), IMI, and SME, leading to lower sensitivity of FRI-1 activity to β-lactamase inhibitors. The blaFRI-1 gene was located on a ca. 110-kb untypeable, transferable, and non-self-conjugative plasmid. A putative LysR family regulator-encoding gene at the 5' end of the β-lactamase gene was identified, leading to inducible expression of the blaFRI-1 gene. PMID:26392482

  19. Hydrolysis of 4-Hydroxybenzoic Acid Esters (Parabens) and Their Aerobic Transformation into Phenol by the Resistant Enterobacter cloacae Strain EM

    PubMed Central

    Valkova, Nelly; Lépine, François; Valeanu, Loredana; Dupont, Maryse; Labrie, Louisette; Bisaillon, Jean-Guy; Beaudet, Réjean; Shareck, François; Villemur, Richard

    2001-01-01

    Enterobacter cloacae strain EM was isolated from a commercial dietary mineral supplement stabilized by a mixture of methylparaben and propylparaben. It harbored a high-molecular-weight plasmid and was resistant to high concentrations of parabens. Strain EM was able to grow in liquid media containing similar amounts of parabens as found in the mineral supplement (1,700 and 180 mg of methyl and propylparaben, respectively, per liter or 11.2 and 1.0 mM) and in very high concentrations of methylparaben (3,000 mg liter−1, or 19.7 mM). This strain was able to hydrolyze approximately 500 mg of methyl-, ethyl-, or propylparaben liter−1 (3 mM) in less than 2 h in liquid culture, and the supernatant of a sonicated culture, after a 30-fold dilution, was able to hydrolyze 1,000 mg of methylparaben liter−1 (6.6 mM) in 15 min. The first step of paraben degradation was the hydrolysis of the ester bond to produce 4-hydroxybenzoic acid, followed by a decarboxylation step to produce phenol under aerobic conditions. The transformation of 4-hydroxybenzoic acid into phenol was stoichiometric. The conversion of approximately 500 mg of parabens liter−1 (3 mM) to phenol in liquid culture was completed within 5 h without significant hindrance to the growth of strain EM, while higher concentrations of parabens partially inhibited its growth. PMID:11375144

  20. Study on biodegradation of Mazut by newly isolated strain Enterobacter cloacae BBRC10061: improving and kinetic investigation

    PubMed Central

    2013-01-01

    Mazut as a source content of various hydrocarbons is hard to be degraded and its cracking could turn mazut into useful materials. Nevertheless degradation of mazut by routine methods is too expensive but application of indigenous microorganisms as biocatalysts could be effective and important to lower the costs and expand its consumption. Mazut biodegradation can be improved using various strategies; Therefore in this study newly isolated strain Enterobacter cloacae BBRC 10061 was used in a method of gradual addition of mazut into medium and its results were compared with simple addition method. To investigate degradation of mazut by BBRC 10061, influence of increase of mazut concentration was assayed based on gradual addition method. Also different kinetic models were used to evaluate kinetics of the process. Results showed that gradual addition method has been a beneficial technique for improvement of mazut degradation because bacterial induction to produce biosurfactant and essential enzymes for cracking mazut was higher during process. Although addition of more mazut increased the rate of biodegradation but percentage of degradation decreased. pH of medium decreased during biodegradation period while electric potential increased. Also the biodegradation kinetics was not fitted with the biokinetic models; therefore kinetics of biodegradation of mazut has to be studied by new models. PMID:23369455

  1. Production and assay of cellulolytic enzyme activity of Enterobacter cloacae WPL 214 isolated from bovine rumen fluid waste of Surabaya abbatoir, Indonesia

    PubMed Central

    Lokapirnasari, W. P.; Nazar, D. S.; Nurhajati, T.; Supranianondo, K.; Yulianto, A. B.

    2015-01-01

    Aim: This study aims to produce and assay cellulolytic enzyme activity (endo-(1,4)-β-D-glucanase, exo-(1,4)-β-D-glucanase, and β-glucosidase, at optimum temperature and optimum pH) of Enterobacter cloacae WPL 214 isolated from bovine rumen fluid waste of Surabaya Abbatoir, Indonesia. Materials and Methods: To produce enzyme from a single colony of E. cloacae WPL 214, 98 × 1010 CFU/ml of isolates was put into 20 ml of liquid medium and incubated in a shaker incubator for 16 h at 35°C in accordance with growth time and optimum temperature of E. cloacae WPL 214. Further on, culture was centrifuged at 6000 rpm at 4°C for 15 min. Pellet was discarded while supernatant containing cellulose enzyme activity was withdrawn to assay endo-(1,4)-β-D-glucanase, exo-(1,4)-β-D-glucanase, and β-glucosidase. Results: Cellulase enzyme of E. cloacae WPL 214 isolates had endoglucanase activity of 0.09 U/ml, exoglucanase of 0.13 U/ml, and cellobiase of 0.10 U/ml at optimum temperature 35°C and optimum pH 5. Conclusion: E. cloacae WPL 214 isolated from bovine rumen fluid waste produced cellulose enzyme with activity as cellulolytic enzyme of endo-(1,4)-β-D-glucanase, exo-(1,4)-β-D-glucanase and β-glucosidase. PMID:27047099

  2. Plasmid-mediated gene transfer between insect-resident bacteria, Enterobacter cloacae, and plant-epiphytic bacteria, Erwinia herbicola, in guts of silkworm larvae.

    PubMed

    Watanabe, K; Sato, M

    1998-11-01

    Five strains of Enterobacter cloacae isolated from several species of plants and insects were able to grow in the guts of silkworm larvae. A much larger population of Ent. cloacae strains was detected in the insect guts and feces collected 3 and 6 days than in samples collected 1 day after feeding artificial diets contaminating these bacteria. Furthermore, insect-origin strains of Ent. cloacae were mated with a donor strain, epiphytic Erwinia herbicola, harboring RSF1010 and pBPW1::Tn7 plasmids in the insect guts by introducing these bacteria through separate artificial diets administered at different times. A number of transconjugants, Ent. cloacae strains which had acquired RSF1010 plasmid, were detected from guts and fecal samples at transfer frequencies of 10(-2) to 10(-3) per recipient. Thus, gene transfer between epiphytic Er. herbicola and insect-resident Ent. cloacae strains in the insect guts was confirmed. These findings may provide significant information about the role of "in insecta mating" in the evolution of these bacteria. PMID:9767717

  3. Differential inactivation of seed exudate stimulation of Pythium ultimum sporangium germination by Enterobacter cloacae influences biological control efficacy on different plant species.

    PubMed

    Kageyama, Koji; Nelson, Eric B

    2003-02-01

    This study was initiated to understand whether differential biological control efficacy of Enterobacter cloacae on various plant species is due to differences in the ability of E. cloacae to inactivate the stimulatory activity of seed exudates to Pythium ultimum sporangium germination. In biological control assays, E. cloacae was effective in controlling Pythium damping-off when placed on the seeds of carrot, cotton, cucumber, lettuce, radish, tomato, and wheat but failed to protect corn and pea from damping-off. Seeds from plants such as corn and pea had high rates of exudation, whereas cotton and cucumber seeds had much lower rates of exudation. Patterns of seed exudation and the release of P. ultimum sporangium germination stimulants varied among the plants tested. Seed exudates of plants such as carrot, corn, lettuce, pea, radish, and wheat were generally more stimulatory to P. ultimum than were the exudates of cotton, cucumber, sunflower, and tomato. However, this was not directly related to the ability of E. cloacae to inactivate the stimulatory activity of the exudate and reduce P. ultimum sporangium germination. In the spermosphere, E. cloacae readily reduced the stimulatory activity of seed exudates from all plant species except corn and pea. Our data have shown that the inability of E. cloacae to protect corn and pea seeds from Pythium damping-off is directly related to its ability to inactivate the stimulatory activity of seed exudates. On all other plants tested, E. cloacae was effective in suppressing damping-off and inactivating the stimulatory activity of seed exudates. PMID:12571037

  4. Dynamics of MDR Enterobacter cloacae outbreaks in a neonatal unit in Nepal: insights using wider sampling frames and next-generation sequencing

    PubMed Central

    Stoesser, N.; Sheppard, A. E.; Shakya, M.; Sthapit, B.; Thorson, S.; Giess, A.; Kelly, D.; Pollard, A. J.; Peto, T. E. A.; Walker, A. S.; Crook, D. W.

    2015-01-01

    Objectives There are limited data on Enterobacter cloacae outbreaks and fewer describing these in association with NDM-1. With whole-genome sequencing, we tested the hypothesis that a cluster of 16 E. cloacae bacteraemia cases in a Nepali neonatal unit represented a single clonal outbreak, using a wider set of epidemiologically unrelated clinical E. cloacae isolates for comparison. Methods Forty-three isolates were analysed, including 23 E. cloacae and 3 Citrobacter sp. isolates obtained from blood cultures from 16 neonates over a 3 month period. These were compared with two contemporaneous community-associated drug-resistant isolates from adults, a unit soap dispenser isolate and a set of historical invasive isolates (n = 14) from the same geographical locality. Results There were two clear neonatal outbreaks and one isolated case in the unit. One outbreak was associated with an NDM-1 plasmid also identified in a historical community-associated strain. The smaller, second outbreak was likely associated with a contaminated soap dispenser. The two community-acquired adult cases and three sets of historical hospital-associated neonatal isolates represented four additional genetic clusters. Conclusions E. cloacae infections in this context represent several different transmission networks, operating at the community/hospital and host strain/plasmid levels. Wide sampling frames and high-resolution typing methods are needed to describe the complex molecular epidemiology of E. cloacae outbreaks, which is not appropriately reflected by routine susceptibility phenotypes. Soap dispensers may represent a reservoir for E. cloacae and bacterial strains and plasmids may persist in hospitals and in the community for long periods, sporadically being involved in outbreaks of disease. PMID:25558071

  5. New Delhi Metallo-β-Lactamase 1(NDM-1), the Dominant Carbapenemase Detected in Carbapenem-Resistant Enterobacter cloacae from Henan Province, China

    PubMed Central

    Liu, Xuchun; Lang, Shaolei; Feng, Xianju; Liu, Hong-Min

    2015-01-01

    The emergence of New Delhi metallo-β-lactamase 1 (NDM-1) has become established as a major public health threat and represents a new challenge in the treatment of infectious diseases. In this study, we report a high incidence and endemic spread of NDM-1-producing carbapenem-resistant Enterobacter cloacae isolates in Henan province, China. Eight (72.7%) out of eleven non-duplicated carbapenem-resistant E. cloacae isolates collected between June 2011 and May 2013 were identified as NDM-1 positive. The blaNDM-1 gene surrounded by an entire ISAba125 element and a bleomycin resistance gene bleMBL in these isolates were carried by diverse conjugatable plasmids (IncA/C, IncN, IncHI2 and untypeable) ranging from ~55 to ~360 kb. Molecular epidemiology analysis revealed that three NDM-1-producing E. cloacae belonged to the same multilocus sequence type (ST), ST120, two of which were classified as extensively drug-resistant (XDR) isolates susceptible only to tigecycline and colistin. The two XDR ST120 E. cloacae isolates co-harbored blaNDM-1, armA and fosA3 genes and could transfer resistance to carbapenems, fosfomycin and aminoglycosides simultaneously via a conjugation experiment. Our study demonstrated NDM-1 was the most prevalent metallo-β-lactamase (MBL) among carbapenem-resistant E.cloacae isolates and identified a potential endemic clone of ST120 in Henan province. These findings highlight the need for enhanced efforts to monitor the further spread of NDM-1 and XDR ST120 E. cloacae in this region. PMID:26263489

  6. Characterization of SFO-1, a plasmid-mediated inducible class A beta-lactamase from Enterobacter cloacae.

    PubMed

    Matsumoto, Y; Inoue, M

    1999-02-01

    Enterobacter cloacae 8009 produced an inducible class A beta-lactamase which hydrolyzed cefotaxime efficiently. It also hydrolyzed other beta-lactams except cephamycins and carbapenems. The activity was inhibited by clavulanic acid and imipenem. The bla gene was transferable to Escherichia coli by electroporation of plasmid DNA. The molecular mass of the beta-lactamase was 29 kDa and its pI was 7.3. All of these phenotypic characteristics of the enzyme except for inducible production resemble those of some extended-spectrum class A beta-lactamases like FEC-1. The gene encoding this beta-lactamase was cloned and sequenced. The deduced amino acid sequence of the beta-lactamase was homologous to the AmpA sequences of the Serratia fonticola chromosomal enzyme (96%), MEN-1 (78%), Klebsiella oxytoca chromosomal enzymes (77%), TOHO-1 (75%), and FEC-1 (72%). The conserved sequences of class A beta-lactamases, including the S-X(T)-X(S)-K motif, in the active site were all conserved in this enzyme. On the basis of the high degree of homology to the beta-lactamase of S. fonticola, the enzyme was named SFO-1. The ampR gene was located upstream of the ampA gene, and the AmpR sequence of SFO-1 had homology with the AmpR sequences of the chromosomal beta-lactamases from Citrobacter diversus (80%), Proteus vulgaris (68%), and Pseudomonas aeruginosa (60%). SFO-1 was also inducible in E. coli. However, a transformant harboring plasmid without intact ampR produced a small amount of beta-lactamase constitutively, suggesting that AmpR works as an activator of ampA of SFO-1. This is the first report from Japan describing an inducible plasmid-mediated class A beta-lactamase in gram-negative bacteria. PMID:9925524

  7. Quantifying the effect of hand wash duration, soap use, ground beef debris, and drying methods on the removal of Enterobacter aerogenes on hands.

    PubMed

    Jensen, Dane A; Danyluk, Michelle D; Harris, Linda J; Schaffner, Donald W

    2015-04-01

    Hand washing is recognized as a crucial step in preventing foodborne disease transmission by mitigating crosscontamination among hands, surfaces, and foods. This research was undertaken to establish the importance of several keys factors (soap, soil, time, and drying method) in reducing microorganisms during hand washing. A nonpathogenic nalidixic acid-resistant Enterobacter aerogenes surrogate for Salmonella was used to assess the efficacy of using soap or no soap for 5 or 20 s on hands with or without ground beef debris and drying with paper towel or air. Each experiment consisted of 20 replicates, each from a different individual with ∼ 6 log CFU/ml E. aerogenes on their hands. A reduction of 1.0 ± 0.4 and 1.7 ± 0.8 log CFU of E. aerogenes was observed for a 5-s wash with no soap and a 20-s wash with soap, respectively. When there was no debris on the hands, there was no significant difference between washing with and without soap for 20 s (P > 0.05). Likewise, there was no significant difference in the reductions achieved when washing without soap, whether or not debris was on the hands (P > 0.05). A significantly greater reduction (P < 0.05) in E. aerogenes (0.5 log CFU greater reduction) was observed with soap when there was ground beef debris on the hands. The greatest difference (1.1 log CFU greater average reduction) in effectiveness occurred when ground beef debris was on the hands and a 20-s wash with water was compared with a 20-s wash with soap. Significantly greater (P < 0.05) reductions were observed with paper towel drying compared with air (0.5 log CFU greater reductions). Used paper towels may contain high bacterial levels (>4.0 log CFU per towel) when hands are highly contaminated. Our results support future quantitative microbial risk assessments needed to effectively manage risks of foodborne illness in which food workers' hands are a primary cause. PMID:25836392

  8. Common mechanism of ampC beta-lactamase induction in enterobacteria: regulation of the cloned Enterobacter cloacae P99 beta-lactamase gene.

    PubMed Central

    Lindberg, F; Normark, S

    1987-01-01

    Expression of the chromosomal beta-lactamase from the ampC gene in inducible in both Enterobacter cloacae and Citrobacter freundii. Cloning of ampC as well as its regulatory gene, ampR, from E. cloacae P99 revealed a gene organization indentical to that of C. freundii in the corresponding region. Although almost no similarities could be found between the restriction maps of ampC and ampR in the two species, the genes cross-hybridize. Also, both ampR gene products have a size of about 31,000. The regulatory features of E. cloacae beta-lactamase induction are very similar to those in C. freundii, i.e., beta-lactamase synthesis is repressed by AmpR in the absence, and stimulated in the presence, of inducer. The AmpR function can be transcomplemented between the two species, but there are quantitative regulatory aberrations in such hybrids, in contrast to the total complementation obtained within each system. These results suggest that the mechanism of beta-lactamase induction is the same in E. cloacae, C. freundii, and other gram-negative bacteria with inducible chromosomal beta-lactamase expression. Images PMID:3027046

  9. Comparative evaluation of fermentative hydrogen production using Enterobacter cloacae and mixed culture: effect of Pd (II) ion and phytogenic palladium nanoparticles.

    PubMed

    Mohanraj, Sundaresan; Anbalagan, Krishnasamy; Kodhaiyolii, Shanmugam; Pugalenthi, Velan

    2014-12-20

    Palladium nanoparticles (PdNPs) were synthesized from PdCl2 using Coriandrum sativum leaf extract. The transmission electron microscopy (TEM) images confirm that the formation of PdNPs was mainly spherical in shape, with an average size of 87 nm. The influence of the PdCl2 and synthesized PdNPs on fermentative hydrogen production from glucose using Enterobacter cloacae and mixed culture was evaluated. In PdCl2 supplemented experiments, the hydrogen yields of E. cloacae and mixed culture were 1.39 ± 0.07 and 2.11 ± 0.11 mol H2/mol glucose, respectively, with 5.0 mg/L of PdCl2. The resulting hydrogen yield (P < 0.05) was lower than that of the control experiment (without supplementation), due to the soluble metabolites shift. However, the highest hydrogen yields of E. cloacae and mixed culture were 1.48 ± 0.04 and 2.48 ± 0.09 mol H2/mol glucose, respectively at 5.0 mg/L of PdNPs supplementation. The enhancement of biohydrogen production using mixed culture was significantly higher than that of E. cloacae as the same concentration of PdNPs. PMID:25456058

  10. Se(VI) Reduction and the Precipitation of Se(0) Precipitation by the Facultative Bacterium Enterobacter Cloacae SLD1a-1 is Regulated by FNR

    SciTech Connect

    Yee,N.; Ma, J.; Dalia, A.; Boonfueng, T.; Kobayashi, D.

    2007-01-01

    The fate of selenium in the environment is controlled, in part, by microbial selenium oxyanion reduction and Se(0) precipitation. In this study, we identified a genetic regulator that controls selenate reductase activity in the Se-reducing bacterium Enterobacter cloacae SLD1a-1. Heterologous expression of the global anaerobic regulatory gene fnr (fumarate nitrate reduction regulator) from E. cloacae in the non-Se-reducing strain Escherichia coli S17-1 activated the ability to reduce Se(VI) and precipitate insoluble Se(0) particles. Se(VI) reduction by E. coli S17-1 containing the fnr gene occurred at rates similar to those for E. cloacae, with first-order reaction constants of k = 2.07 x 10{sup -2} h{sup -1} and k = 3.36 x 10{sup -2} h{sup -1}, respectively, and produced elemental selenium particles with identical morphologies and short-range atomic orders. Mutation of the fnr gene in E. cloacae SLD1a-1 resulted in derivative strains that were deficient in selenate reductase activity and unable to precipitate elemental selenium. Complementation by the wild-type fnr sequence restored the ability of mutant strains to reduce Se(VI). Our findings suggest that Se(VI) reduction and the precipitation of Se(0) by facultative anaerobes are regulated by oxygen-sensing transcription factors and occur under suboxic conditions.

  11. Detection and Characterization of VIM-31, a New Variant of VIM-2 with Tyr224His and His252Arg Mutations, in a Clinical Isolate of Enterobacter cloacae

    PubMed Central

    Bebrone, Carine; Huang, Te-Din; Bouchahrouf, Warda; DeGheldre, Yves; Deplano, Ariane; Hoffmann, Kurt; Glupczynski, Youri

    2012-01-01

    We report the first description of the metallo-β-lactamase VIM-31, a new variant of VIM-2 with Tyr224His and His252Arg mutations, in Enterobacter cloacae 11236, which was isolated from blood specimens of a patient with colonic adenocarcinoma in Belgium. blaVIM-31 was found on a class 1 integron located on a self-transferable but not typeable 42-kb plasmid. Compared to values published elsewhere for VIM-2, the purified VIM-31 enzyme showed weaker catalytic efficiency against all the tested beta-lactam agents (except for ertapenem), resulting from lower kcat (except for ertapenem) and higher Km values for VIM-31. PMID:22391550

  12. Coproduction of KPC-18 and VIM-1 Carbapenemases by Enterobacter cloacae: Implications for Newer β-Lactam-β-Lactamase Inhibitor Combinations.

    PubMed

    Thomson, Gina K; Snyder, James W; McElheny, Christi L; Thomson, Kenneth S; Doi, Yohei

    2016-03-01

    Enterobacter cloacae strain G6809 with reduced susceptibility to carbapenems was identified from a patient in a long-term acute care hospital in Kentucky. G6809 belonged to sequence type (ST) 88 and carried two carbapenemase genes, bla(KPC-18) and bla(VIM-1). Whole-genome sequencing localized bla(KPC-18) to the chromosome and bla(VIM-1) to a 58-kb plasmid. The strain was highly resistant to ceftazidime-avibactam. Insidious coproduction of metallo-β-lactamase with KPC-type carbapenemase has implications for the use of next-generation β-lactam-β-lactamase inhibitor combinations. PMID:26719440

  13. Draft Genome Sequence of Hydrocarbon-Degrading Enterobacter cloacae Strain S1:CND1, Isolated from Crude Oil-Contaminated Soil from the Noonmati Oil Refinery, Guwahati, Assam, India

    PubMed Central

    Mukherjee, Arghya; Chettri, Bobby; Langpoklakpam, James S.; Singh, Arvind K.

    2016-01-01

    We report here the 4.57-Mb draft genome sequence of hydrocarbon-degrading Enterobacter cloacae strain S1:CND1 isolated from oil-contaminated soil in Guwahati, India. S1:CND1 contains 4,205 coding sequences and has a G+C content of 57.45%. This is the first report of the genome sequence of an E. cloacae adapted to an oil-contaminated environment. PMID:27174279

  14. In Vitro Activity of Polymyxin B in Combination with Various Antibiotics against Extensively Drug-Resistant Enterobacter cloacae with Decreased Susceptibility to Polymyxin B.

    PubMed

    Cai, Yiying; Lim, Tze-Peng; Teo, Jocelyn; Sasikala, Suranthran; Lee, Winnie; Hong, Yanjun; Chan, Eric Chun Yong; Tan, Thean Yen; Tan, Thuan-Tong; Koh, Tse Hsien; Hsu, Li Yang; Kwa, Andrea L

    2016-09-01

    Against extensively drug-resistant (XDR) Enterobacter cloacae, combination antibiotic therapy may be the only option. We investigated the activity of various antibiotics in combination with polymyxin B using time-kill studies (TKS). TKS were conducted with four nonclonal XDR E. cloacae isolates with 5 log10 CFU/ml bacteria against maximum, clinically achievable concentrations of polymyxin B alone and in two-drug combinations with 10 different antibiotics. A hollow-fiber infection model (HFIM) simulating clinically relevant polymyxin B and tigecycline dosing regimens was conducted for two isolates over 240 h. Emergence of resistance was quantified using antibiotic-containing (3× MIC) media. Biofitness and stability of resistant phenotypes were determined. All XDR E. cloacae isolates were resistant to all antibiotics except for polymyxin B (polymyxin B MIC, 1 to 4 mg/liter). All isolates harbored metallo-β-lactamases (two with NDM-1, two with IMP-1). In single TKS, all antibiotics alone demonstrated regrowth at 24 h, except amikacin against two strains and polymyxin B and meropenem against one strain each. In combination TKS, only polymyxin B plus tigecycline was bactericidal against all four XDR E. cloacae isolates at 24 h. In HFIM, tigecycline and polymyxin B alone did not exhibit any killing activity. Bactericidal kill was observed at 24 h for both isolates for polymyxin B plus tigecycline; killing was sustained for one isolate but regrowth was observed for the second. Phenotypically stable resistant mutants with reduced in vitro growth rates were observed. Polymyxin B plus tigecycline is a promising combination against XDR E. cloacae However, prolonged and indiscriminate use can result in resistance emergence. PMID:27324776

  15. Expression of Zinc Transporter Genes in Rice as Influenced by Zinc-Solubilizing Enterobacter cloacae Strain ZSB14.

    PubMed

    Krithika, Selvaraj; Balachandar, Dananjeyan

    2016-01-01

    Zinc (Zn) deficiency in major food crops has been considered as an important factor affecting the crop production and subsequently the human health. Rice (Oryza sativa) is sensitive to Zn deficiency and thereby causes malnutrition to most of the rice-eating Asian populations. Application of zinc solubilizing bacteria (ZSB) could be a sustainable agronomic approach to increase the soil available Zn which can mitigate the yield loss and consequently the nutritional quality of rice. Understanding the molecular interactions between rice and unexplored ZSB is useful for overcoming Zn deficiency problems. In the present study, the role of zinc solubilizing bacterial strain Enterobacter cloacae strain ZSB14 on regulation of Zn-regulated transporters and iron (Fe)-regulated transporter-like protein (ZIP) genes in rice under iron sufficient and deficient conditions was assessed by quantitative real-time reverse transcription PCR. The expression patterns of OsZIP1, OsZIP4, and OsZIP5 in root and shoot of rice were altered due to the Zn availability as dictated by Zn sources and ZSB inoculation. Fe sufficiency significantly reduced the root and shoot OsZIP1 expression, but not the OsZIP4 and OsZIP5 levels. Zinc oxide in the growth medium up-regulated all the assessed ZIP genes in root and shoot of rice seedlings. When ZSB was inoculated to rice seedlings grown with insoluble zinc oxide in the growth medium, the expression of root and shoot OsZIP1, OsZIP4, and OsZIP5 was reduced. In the absence of zinc oxide, ZSB inoculation up-regulated OsZIP1 and OsZIP5 expressions. Zinc nutrition provided to the rice seedling through ZSB-bound zinc oxide solubilization was comparable to the soluble zinc sulfate application which was evident through the ZIP genes' expression and the Zn accumulation in root and shoot of rice seedlings. These results demonstrate that ZSB could play a crucial role in zinc fertilization and fortification of rice. PMID:27092162

  16. Expression of Zinc Transporter Genes in Rice as Influenced by Zinc-Solubilizing Enterobacter cloacae Strain ZSB14

    PubMed Central

    Krithika, Selvaraj; Balachandar, Dananjeyan

    2016-01-01

    Zinc (Zn) deficiency in major food crops has been considered as an important factor affecting the crop production and subsequently the human health. Rice (Oryza sativa) is sensitive to Zn deficiency and thereby causes malnutrition to most of the rice-eating Asian populations. Application of zinc solubilizing bacteria (ZSB) could be a sustainable agronomic approach to increase the soil available Zn which can mitigate the yield loss and consequently the nutritional quality of rice. Understanding the molecular interactions between rice and unexplored ZSB is useful for overcoming Zn deficiency problems. In the present study, the role of zinc solubilizing bacterial strain Enterobacter cloacae strain ZSB14 on regulation of Zn-regulated transporters and iron (Fe)-regulated transporter-like protein (ZIP) genes in rice under iron sufficient and deficient conditions was assessed by quantitative real-time reverse transcription PCR. The expression patterns of OsZIP1, OsZIP4, and OsZIP5 in root and shoot of rice were altered due to the Zn availability as dictated by Zn sources and ZSB inoculation. Fe sufficiency significantly reduced the root and shoot OsZIP1 expression, but not the OsZIP4 and OsZIP5 levels. Zinc oxide in the growth medium up-regulated all the assessed ZIP genes in root and shoot of rice seedlings. When ZSB was inoculated to rice seedlings grown with insoluble zinc oxide in the growth medium, the expression of root and shoot OsZIP1, OsZIP4, and OsZIP5 was reduced. In the absence of zinc oxide, ZSB inoculation up-regulated OsZIP1 and OsZIP5 expressions. Zinc nutrition provided to the rice seedling through ZSB-bound zinc oxide solubilization was comparable to the soluble zinc sulfate application which was evident through the ZIP genes’ expression and the Zn accumulation in root and shoot of rice seedlings. These results demonstrate that ZSB could play a crucial role in zinc fertilization and fortification of rice. PMID:27092162

  17. Isolation of a strong promoter fragment from endophytic Enterobacter cloacae and verification of its promoter activity when its host strain colonizes banana plants.

    PubMed

    Wang, Yu Guang; Xia, Qi Yu; Gu, Wen Liang; Sun, Jian Bo; Zhang, He; Lu, Xue Hua; Lu, Juan; Peng, Ming; Zhang, Xin

    2012-02-01

    To engineer endophytic Enterobacter cloacae as a biocontrol agent against banana fusarium wilt, a promoter-probe plasmid pUCK was constructed to identify a strong promoter to express disease resistance genes. Using a kanamycin resistance gene for selection, 10 fragments with strong promoter activity were identified from the genome of the E. cloacae KKWB-10 strain. The regions of these 10 fragments that were the primary contributors to the promoter function were identified, and their promoter activities were further evaluated using green fluorescent protein (GFP) as a reporter gene. Fragment 132a″ drove the highest level of GFP activity when the bacteria bearing the fragments were cultured in Luria-Bertani and banana stem extract media. The GFP-expressing strain harboring fragment 132a″ (K-pUCK7-132a″-GT) was then inoculated into banana plantlets (about 1 × 10(7) CFU per plant) to verify the activity of fragment 132a″ in planta. Ten days after inoculation, tissue sections of these banana plantlets were observed by laser confocal scanning microscope. Green fluorescence was observed in the tissues of banana plantlets inoculated with K-pUCK7-132a″-GT but not in uninoculated controls. These results suggest that fragment 132a″ possesses strong promoter activity when its host strain colonizes the banana plants and can be used to engineer endophytic E. cloacae KKWB-10 for biocontrol. PMID:22080347

  18. Epidemiological fingerprinting of Enterobacter cloacae by small-fragment restriction endonuclease analysis and pulsed-field gel electrophoresis of genomic restriction fragments.

    PubMed Central

    Haertl, R; Bandlow, G

    1993-01-01

    A cluster of infections caused by Enterobacter cloacae was observed among preterm neonates in a neonatal intensive care unit (NICU) of a pediatric hospital in Osnabrück, Germany. The presence of similar antimicrobial susceptibility patterns among the bacterial isolates prompted an investigation to determine whether a limited spread of a single strain existed. All 12 E. cloacae isolates from the NICU and 50 nonrelated strains were fingerprinted by small-fragment restriction endonuclease analysis (SF-REA) of EcoRI DNA digests. Selected isolates were further characterized by pulsed-field gel electrophoresis (PFGE) of NotI- or XbaI-generated genomic restriction fragments. Epidemiologically unrelated strains were clearly discriminated by both methods. Results achieved by SF-REA and PFGE revealed that of the 12 isolates from the NICU, 11 belonged to the same genotypic cluster. Since all reagents and equipment for both techniques are commercially available, DNA fingerprinting by SF-REA or PFGE is proposed as a useful tool in the microbiology laboratory for investigating the epidemiological relatedness of E. cloacae strains of clinical and environmental origin. Images PMID:8093251

  19. NDM-1 encoded by a pNDM-BJ01-like plasmid p3SP-NDM in clinical Enterobacter aerogenes

    PubMed Central

    Chen, Zhenhong; Li, Hongxia; Feng, Jiao; Li, Yuxue; Chen, Xin; Guo, Xuemin; Chen, Weijun; Wang, Li; Lin, Lei; Yang, Huiying; Yang, Wenhui; Wang, Jie; Zhou, Dongsheng; Liu, Changting; Yin, Zhe

    2015-01-01

    A carbapenem-nonsusceptible Enterobacter aerogenes strain named 3-SP was isolated from a human case of pneumonia in a Chinese teaching hospital. NDM-1 carbapenemase is produced by a pNDM-BJ01-like conjugative plasmid designated p3SP-NDM to account for carbapenem resistance of 3-SP. p3SP-NDM was fully sequenced and compared with all publically available pNDM-BJ01-like plasmids. The genetic differences between p3SP-NDM and pNDM-BJ01 include only 18 single nucleotide polymorphisms, a 1 bp deletion and a 706 bp deletion. p3SP-NDM and pNDM-BJ01 harbor an identical Tn125 element organized as ISAba125, blaNDM−1, bleMBL, ΔtrpF, dsbC, cutA, ΔgroES, groEL, ISCR27, and ISAba125. The blaNDM−1 surrounding regions in these pNDM-BJ01-like plasmids have a conserved linear organization ISAba14-aphA6-Tn125-unknown IS, with considerable genetic differences identified within or immediately downstream of Tn125. All reported pNDM-BJ01-like plasmids are exclusively found in Acinetobacter, whereas this is the first report of identification of a pNDM-BJ01-like plasmid in Enterobacteriaceae. PMID:25926823

  20. Malonate-bound structure of the glycerophosphodiesterase from Enterobacter aerogenes (GpdQ) and characterization of the native Fe[supscript 2+] metal-ion preference

    SciTech Connect

    Jackson, Colin J.; Hadler, Kieran S.; Carr, Paul D.; Oakley, Aaron J.; Yip, Sylvia; Schenk, Gerhard; Ollis, David L.

    2010-09-20

    The structure of a malonate-bound form of the glycerophosphodiesterase from Enterobacter aerogenes, GpdQ, has been refined at a resolution of 2.2 {angstrom} to a final R factor of 17.1%. The structure was originally solved to 2.9 {angstrom} resolution using SAD phases from Zn{sup 2+} metal ions introduced into the active site of the apoenzyme [Jackson et al. (2007), J. Mol. Biol. 367, 1047-1062]. However, the 2.9 {angstrom} resolution was insufficient to discern significant details of the architecture of the binuclear metal centre that constitutes the active site. Furthermore, kinetic analysis revealed that the enzyme lost a significant amount of activity in the presence of Zn{sup 2+}, suggesting that it is unlikely to be a catalytically relevant metal ion. In this communication, a higher resolution structure of GpdQ is presented in which malonate is visibly coordinated in the active site and analysis of the native metal-ion preference is presented using atomic absorption spectroscopy and anomalous scattering. Catalytic implications of the structure and its Fe{sup 2+} metal-ion preference are discussed.

  1. Malonate-bound structure of the glycerophosphodiesterase from Enterobacter aerogenes (GpdQ) and characterization of the native Fe[superscript 2+] metal-ion preference

    SciTech Connect

    Jackson, Colin J.; Hadler, Kieran S.; Carr, Paul D.; Oakley, Aaron J.; Yip, Sylvia; Schenk, Gerhard; Ollis, David L.

    2011-09-28

    The structure of a malonate-bound form of the glycerophosphodiesterase from Enterobacter aerogenes, GpdQ, has been refined at a resolution of 2.2 {angstrom} to a final R factor of 17.1%. The structure was originally solved to 2.9 {angstrom} resolution using SAD phases from Zn{sup 2+} metal ions introduced into the active site of the apoenzyme [Jackson et al. (2007), J. Mol. Biol. 367, 1047-1062]. However, the 2.9 {angstrom} resolution was insufficient to discern significant details of the architecture of the binuclear metal centre that constitutes the active site. Furthermore, kinetic analysis revealed that the enzyme lost a significant amount of activity in the presence of Zn2+, suggesting that it is unlikely to be a catalytically relevant metal ion. In this communication, a higher resolution structure of GpdQ is presented in which malonate is visibly coordinated in the active site and analysis of the native metal-ion preference is presented using atomic absorption spectroscopy and anomalous scattering. Catalytic implications of the structure and its Fe{sup 2+} metal-ion preference are discussed.

  2. Fate of Enterobacter cloacae JP120 and Alcaligenes eutrophus AEO106(pRO101) in soil during water stress: effects on culturability and viability.

    PubMed

    Pedersen, J C; Jacobsen, C S

    1993-05-01

    A sandy loam soil near field capacity moisture content (psi = -0.050 MPa) or air dried (psi = -300 MPa) was inoculated with about 3 x 10(7) CFU of Enterobacter cloacae JP120 and Alcaligenes eutrophus AEO106(pRO101) per g and incubated in 40-g portions at 17 degrees C in closed or open Erlenmeyer flasks. In the field-moist soil, selective plating, direct viable counts, and DNA hybridization showed only minor changes in the numbers of E. cloacae and A. eutrophus cells with time (14 days), and the results obtained with the three detection methods generally agreed. In the air-dried soil, the majority of both bacteria were found as intact DNA-carrying cells that were neither culturable nor viable by the methods employed in this study. The numbers of culturable E. cloacae and A. eutrophus cells dropped to 10(5) and 10(2) CFU/g, respectively, 2 h after inoculation. Direct viable counts showed that only about 1% of the cells detected by immunofluorescence microscopy were viable, but a fraction of viable nonculturable cells of both bacteria was present. A. eutrophus did not tolerate desiccation as well as E. cloacae. Only a minor fraction of the two test organisms regained their culturability or viability after rewetting of the air-dried soil; the number of total heterotrophic culturable bacteria, however, increased more than 10-fold and reached 73% of the level found in the field-moist soil at day 14. PMID:8517752

  3. Mutation of rpiA in Enterobacter cloacae decreases seed and root colonization and biocontrol of damping-off caused by Pythium ultimum on cucumber.

    PubMed

    Lohrke, Scott M; Dery, Pierre D; Li, Wei; Reedy, Ralph; Kobayashi, Donald Y; Roberts, Daniel R

    2002-08-01

    Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops. E. cloacae A145 is a mini-Tn5 Km transposon mutant of strain 501R3 that was significantly reduced in suppression of damping-off on cucumber caused by P. ultimum. Strain A145 was deficient in colonization of cucumber, sunflower, and wheat seeds and significantly reduced in colonization of corn and cowpea seeds relative to strain 501R3. Populations of strain A145 were also significantly lower than those of strain 501R3 at all sampling times in cucumber, wheat, and sunflower rhizosphere. Populations of strain A145 were not detectable in any rhizosphere after 42 days, while populations of strain 501R3 remained at substantial levels throughout all experiments. Molecular characterization of strain A145 indicated mini-Tn5 Km was inserted in a region of the E. cloacae genome with a high degree of DNA and amino acid sequence similarity to rpiA, which encodes ribose-5-phosphate isomerase. In Escherichia coli, RpiA catalyzes the interconversion of ribose-5-phosphate and ribulose-5-phosphate and is a key enzyme in the pentose phosphate pathway. Ribose-5-phosphate isomerase activity in cell lysates from strain A145 was approximately 3.5% of that from strain 501R3. In addition, strain A145 was a ribose auxotroph, as expected for an rpiA mutant. Introduction of a 1.0-kb DNA fragment containing only the rpiA homologue into strain A145 restored ribose phosphate isomerase activity, prototrophy, seedling colonization, and disease suppression to levels similar to those associated with strain 501R3. Experiments reported here indicate a key role for rpiA and possibly the pentose phosphate pathway in suppression of damping-off and colonization of subterranean portions of plants by E. cloacae. PMID:12182339

  4. Outbreak of Extended-Spectrum Beta-Lactamase Producing Enterobacter cloacae with High MICs of Quaternary Ammonium Compounds in a Hematology Ward Associated with Contaminated Sinks

    PubMed Central

    Chapuis, Angélique; Amoureux, Lucie; Bador, Julien; Gavalas, Arthur; Siebor, Eliane; Chrétien, Marie-Lorraine; Caillot, Denis; Janin, Marion; de Curraize, Claire; Neuwirth, Catherine

    2016-01-01

    Objective: To investigate an outbreak of extended-spectrum beta-lactamase (ESBL) producing Enterobacter cloacae that occurred in the Hematology ward (24-bed unit) of the François Mitterrand University Hospital (Dijon, France) between January 2011 and December 2013. The outbreak involved 43 patients (10 infected and 33 colonized). Design: We performed environmental analysis to detect multiresistant E. cloacae for comparison with clinical isolates (genotyping by pulsed-field gel electrophoresis and MLST as well as ESBL-typing) and determined the MICs of the quaternary ammonium compounds (QACs) alkyldimethylbenzylammonium chloride (ADBAC) and didecyldimethylammonium chloride (DDAC). A bleach-based cleaning-disinfection program was implemented in December 2012 after mechanical removal of the biofilm in all sinks. Results: We have detected 17 ESBL-producing E. cloacae in patients sink drains, shower drains and medical sink drains. Sequencing of the bla genes performed on 60 strains recovered from patients and environment (n = 43 clinical and n = 17 environmental) revealed that bla CTX−M15 was predominant (37 isolates) followed by bla CTX−M9 plus bla SHV−12 (20 isolates). We observed a great diversity among the isolates: 14 pulsotypes (11 STs) in clinical isolates and 9 pulsotypes (7 STs) in environmental isolates. Six pulsotypes were identical between clinical and environmental isolates. MICs of the quaternary ammonium compounds widely used for disinfection were very high in clinical and environmental isolates. Immediately after the implementation of the disinfection program we noticed a substantial fall in cases number. Our findings demonstrate the role of drains as important reservoir of ESBL-producing E. cloacae and highlight the necessity to settle drains accessible to achieve correct cleaning as well as to use disinfectant with proved activity against nosocomial pathogens. PMID:27462306

  5. A nosocomial outbreak due to Enterobacter cloacae strains with the E. hormaechei genotype in patients treated with fluoroquinolones.

    PubMed Central

    Davin-Regli, A; Bosi, C; Charrel, R; Ageron, E; Papazian, L; Grimont, P A; Cremieux, A; Bollet, C

    1997-01-01

    During a 7-month period, we isolated 21 highly fluoroquinolone-resistant Enterobacter cloaecae strains in units from two hospitals in Marseille, France. Random amplification of polymorphic DNA showed clonal identity between isolates which, furthermore, presented the Enterobacter hormaechei genotype on DNA-DNA hybridization. The emergence of this clone was observed only in patients treated with fluoroquinolones. PMID:9157119

  6. Epidemiology and molecular characterization of extended-spectrum beta-lactamase-producing Enterobacter spp., Pantoea agglomerans, and Serratia marcescens isolates from a Bulgarian hospital.

    PubMed

    Markovska, Rumyana Donkova; Stoeva, Temenuga Jekova; Bojkova, Kalina Dineva; Mitov, Ivan Gergov

    2014-04-01

    Forty-two extended-spectrum beta-lactamase (ESBL)-producing isolates of Enterobacter aerogenes, Enterobacter cloacae, Pantoea agglomerans, and Serratia marcescens, collected consecutively during the period January-November 2011 from the University Hospital in Varna, Bulgaria, were studied to characterize their ESBLs by isoelectric focusing, group-specific PCR, and sequencing. The epidemiological relationship was evaluated by random amplified polymorphic DNA analysis (RAPD). Transferability of ESBL genes was determined by conjugation experiments. Plasmid analysis was done by replicon typing and PstI fingerprinting. The overall rate of ESBL production was 20%. The most widespread enzyme was CTX-M-3, found in 64%. It was dominant in E. aerogenes (100%) and S. marcescens (83%). SHV-12, CTX-M-3, and CTX-M-15 were found among E. cloacae isolates in 50%, 35%, and 45%, respectively. Three main CTX-M-3-producing epidemic clones of E. aerogenes and S. marcescens have been detected. Among E. cloacae isolates, six different RAPD profiles were discerned. The plasmids harboring blaCTX-M-3 belonged to IncL/M type and demonstrated similar PstI fingerprinting profiles. IncFII plasmids were detected in two CTX-M-15-producing E. cloacae isolates. Our results demonstrate wide intrahospital dissemination of clonal E. aerogenes and S. marcescens isolates, carrying IncL/M conjugative plasmids. PMID:24171449

  7. First report of metallo-β-lactamases producing Enterobacter spp. strains from Venezuela.

    PubMed

    Martínez, Dianny; Rodulfo, Hectorina E; Rodríguez, Lucy; Caña, Luisa E; Medina, Belkis; Guzman, Militza; Carreño, Numirin; Marcano, Daniel; De Donato, Marcos

    2014-01-01

    Clinical strains of Enterobacter were isolated from Cumana's Central Hospital in Venezuela, and classified as E. cloacae (21), E. aerogenes (7), E. intermedium (1), E. sakazakii (1) and three unclassified. The strains showed high levels of resistance, especially to SXT (58.1%), CRO (48.8%), CAZ (46.6%), PIP (46.4%), CIP (45.2%) and ATM (43.3%). This is the first report for South America of blaVIM-2 in two E. cloacae and one Enterobacter sp., which also showed multiple mechanisms of resistance. Both E. cloacae showed blaTEM-1, but only one showed blaCTX-M-15 gene, while no blaSHV was detected. PMID:24553611

  8. FIRST REPORT OF METALLO-β-LACTAMASES PRODUCING Enterobacter spp. STRAINS FROM VENEZUELA

    PubMed Central

    Martínez, Dianny; Rodulfo, Hectorina E.; Rodríguez, Lucy; Caña, Luisa E.; Medina, Belkis; Guzman, Militza; Carreño, Numirin; Marcano, Daniel; Donato, Marcos De

    2014-01-01

    Clinical strains of Enterobacter were isolated from Cumana's Central Hospital in Venezuela, and classified as E. cloacae (21), E. aerogenes (7), E. intermedium (1), E. sakazakii (1) and three unclassified. The strains showed high levels of resistance, especially to SXT (58.1%), CRO (48.8%), CAZ (46.6%), PIP (46.4%), CIP (45.2%) and ATM (43.3%). This is the first report for South America of bla VIM-2 in two E. cloacae and one Enterobacter sp., which also showed multiple mechanisms of resistance. Both E. cloacae showed bla TEM-1, but only one showed bla CTX-M-15 gene, while no bla SHV was detected. PMID:24553611

  9. In71, an Enterobacter cloacae blaVIM-1-carrying integron related to In70.2 from Italian Pseudomonas aeruginosa isolates: a SENTRY Antimicrobial Surveillance Program report.

    PubMed

    Castanheira, Mariana; Sader, Hélio S; Jones, Ronald N; Debbia, Eugenio; Picão, Renata C; Gales, Ana C

    2007-01-01

    An Enterobacter cloacae strain showing decreased susceptibility to carbapenems was isolated from a blood culture of a patient hospitalized in Genoa, Italy, and screened for the presence of metallo-beta-lactamase (MBL) genes as part of the SENTRY Antimicrobial Surveillance Program. A bla(VIM-1)-carrying integron named In71 nearly identical to In70.2 reported in Pseudomonas aeruginosa strains isolated from various Italian cities since 2001 was identified in this strain. Interestingly, the In71 did not carry aadA1 nor possess the ISPa7 usually found in the P. aeruginosa integron In70.2. Mobilization of MBL genes from P. aeruginosa to members of the Enterobacteriaceae family is very worrisome because the rapid and wide dissemination of these potent antimicrobial resistance mechanisms could jeopardize the clinical use of carbapenems for the treatment of multidrug-resistant Enterobacteriaceae infections. PMID:17650966

  10. Relative importances of outer membrane permeability and group 1 beta-lactamase as determinants of meropenem and imipenem activities against Enterobacter cloacae.

    PubMed Central

    Cornaglia, G; Russell, K; Satta, G; Fontana, R

    1995-01-01

    The roles of outer membrane permeability and Bush group 1 beta-lactamase activity in determining Enterobacter cloacae susceptibility to either meropenem or imipenem were investigated. A beta-lactamase-deficient strain was obtained by mutagenesis from a clinical isolate of E. cloacae, and a porin-deficient strain was selected from this mutant with cefoxitin. Both strains were transformed with the plasmid pAA20R, which contained the gene coding for the carbapenem-hydrolyzing CphA beta-lactamase, and the carbapenem permeability coefficients were measured by the Zimmermann and Rosselet technique (W. Zimmermann and A. Rosselet, Antimicrob. Agents Chemother. 12:368-372, 1977). The permeability coefficient of meropenem was roughly half that of imipenem in the normally permeable strain and almost seven times lower than that of imipenem in the porin-deficient strain. In the porin-deficient strain, the virtual absence of porins caused the MICs of meropenem to increase from 8 to 16 times, while it did not affect the MICs of imipenem. Conversely, the beta-lactamase affected imipenem but not meropenem activity: meropenem showed a similar activity in the parent strain and in the beta-lactamase-deficient mutant with both a low- and high-density inoculum, whereas imipenem was 16 times less active against the parent strain when the high-density inoculum was used. It is concluded that outer membrane permeability and stability to group 1 beta-lactamase have different impacts on the activities of meropenem and imipenem against E. cloacae. PMID:7726496

  11. New Monoclonal Antibodies against a Novel Subtype of Shiga Toxin 1 Produced by Enterobacter cloacae and Their Use in Analysis of Human Serum

    PubMed Central

    Skinner, Craig; Patfield, Stephanie; Khalil, Rowaida; Kong, Qiulian

    2016-01-01

    ABSTRACT Shiga toxin (Stx) is a major virulence factor of several bacterial pathogens that cause potentially fatal illness, including Escherichia coli and Shigella spp. The continual emergence of new subtypes of Stxs presents challenges for the clinical diagnosis of infections caused by Stx-producing organisms. Here, we report the development of four new monoclonal antibodies (MAbs) against Stx1e, a novel subtype of Stx1 that was produced by an Enterobacter cloacae strain and had limited reactivity with existing anti-Stx1 antibodies. Western blot analysis indicates that these MAbs were Stx1 specific, bound to the A subunit, and had distinct preferences for subtypes of Stx1. Of the four MAbs, Stx1e-2 was capable of partially neutralizing cytotoxicities derived from Stx1e in Vero cells. Enzyme-linked immunosorbent assays assembled with these high-affinity MAbs detected Stx1e at concentrations as low as 4.8 pg/ml in phosphate-buffered saline and 53.6 pg/ml in spiked human serum samples and were also capable of distinguishing Stx1e-producing strains in enriched cultures. These assays may therefore have clinical value in diagnosing Stx1e-producing bacterial infection. Additionally, characteristics of Stx1e, such as the origin of stx1e genes, conditions for toxin expression, receptor binding, and cytotoxicity, were investigated with the new antibodies developed in this study. This information should be useful for further understanding the clinical significance and prevalence of Stx1e-harboring E. cloacae and other organisms. IMPORTANCE Stxs are among the most clinically important virulence factors of Shigella and enterohemorrhagic Escherichia coli. There are many varieties of Stx, and although Stx1a and Stx2a are the most common and widely distributed types of Stx, new variants of Stx are continually emerging. These new variants of Stx can be challenging to detect, since most Stx detection kits are optimized for the detection of Stx1a and Stx2a. Stx1e, recently

  12. Carbapenem Resistance among Enterobacter Species in a Tertiary Care Hospital in Central India

    PubMed Central

    Khajuria, Atul; Praharaj, Ashok Kumar; Kumar, Mahadevan; Grover, Naveen

    2014-01-01

    Objective. To detect genes encoding carbapenem resistance among Enterobacter species in a tertiary care hospital in central India. Methods. Bacterial identification of Enterobacter spp. isolates from various clinical specimens in patients admitted to intensive care units was performed by routine conventional microbial culture and biochemical tests using standard recommended techniques. Antibiotic sensitivity test was performed by standard Kirby Bauer disc diffusion technique. PCR amplification and automated sequencing was carried out. Transfer of resistance genes was determined by conjugation. Results. A total of 70/130 (53.84%) isolates of Enterobacter spp. were found to exhibit reduced susceptibility to imipenem (diameter of zones of inhibition ≤13 mm) by disc diffusion method. Among 70 isolates tested, 48 (68.57%) isolates showed MIC values for imipenem and meropenem ranging from 32 to 64 mg/L as per CLSI breakpoints. All of these 70 isolates were found susceptible to colistin in vitro as per MIC breakpoints (<0.5 mg/L). PCR carried out on these 48 MBL (IP/IPI) E-test positive isolates (12 Enterobacter aerogenes, 31 Enterobacter cloacae, and 05 Enterobacter cloacae complex) was validated by sequencing for beta-lactam resistance genes and result was interpreted accordingly. Conclusion. The study showed MBL production as an important mechanism in carbapenem resistance in Enterobacter spp. and interspecies transfer of these genes through plasmids suggesting early detection by molecular methods. PMID:25180095

  13. Mobilization of the genetically engineered plasmid pHSV106 from Escherichia coli HB101(pHSV106) to Enterobacter cloacae in drinking water.

    PubMed Central

    Sandt, C H; Herson, D S

    1991-01-01

    We have used triparental matings to demonstrate transfer (mobilization) of the nonconjugative genetically engineered plasmid pHSV106, which contains the thymidine kinase gene of herpes simplex virus cloned into pBR322, from Escherichia coli HB101 to an environmental isolate of Enterobacter cloacae in sterile drinking water. This is the first demonstration of a two-step mobilization of a genetically engineered plasmid in any type of fresh water, including drinking water. Transfer was mediated by R plasmid R100-1 of E. coli ED2149(R100-1). Matings in drinking water at 15, 25, and 35 degrees C yielded recombinants, the number of which increased with increasing temperature. Numbers of recombinants obtained were 2 orders of magnitude lower than those obtained from matings in Trypticase soy broth. High concentrations of parental organisms (2.6 x 10(8) to 2.0 x 10(9) CFU/ml) were required. During 1 week of incubation in drinking water, number of parental organisms and recombinants resulting from mobilization remained constant in the absence of indigenous organisms and declined in their presence. Using oligonucleotide probes for the cloned foreign DNA (thymidine kinase gene) and plasmid vector DNA (ampicillin resistance gene), we demonstrated that both genes were transferred to E. cloacae in the mobilization process. In one recombinant selected for detailed study, the plasmids containing these genes differed in size from all forms of pHSV106 present in E. coli HB101(pHSV106), indicating that DNA rearrangement had occurred. This recombinant maintained its plasmids in unchanged form for 15 days in drinking water. A second rearrangement occurred during serial passage of this recombinant on selective media.(ABSTRACT TRUNCATED AT 250 WORDS) Images PMID:2036007

  14. Enterobacter cloacae as biosurfactant producing bacterium: differentiating its effects on interfacial tension and wettability alteration Mechanisms for oil recovery during MEOR process.

    PubMed

    Sarafzadeh, Pegah; Hezave, Ali Zeinolabedini; Ravanbakhsh, Moosa; Niazi, Ali; Ayatollahi, Shahab

    2013-05-01

    Microbial enhanced oil recovery (MEOR) process utilizes microorganisms or their metabolites to mobilize the trapped oil in the oil formation after primary and secondary oil recovery stages. MEOR technique is considered as more environmentally friendly and low cost process. There are several identified mechanisms for more oil recovery using MEOR processes however; wettability alteration and interfacial tension (IFT) reduction are the important ones. Enterobacter Cloacae, a facultative bio-surfactant producer bacterium, was selected as a bacterial formulation due to its known performance on IFT reduction and wettability alteration. To quantify the effects of these two mechanisms, different tests including oil spreading, in situ and ex situ core flooding, wettability measurement (Amott), IFT, viscosity and pH measurements were performed. The obtained results revealed that the experimental procedure used in this study was able to quantitatively identify the individual effects of both mechanisms on the ultimate microbial oil recovery. The results demonstrated considerable effects of both mechanisms on the tertiary oil recovery; however after a proper shut in time period, more tertiary oil was recovered because of wettability alteration mechanism. Finally, SEM images taken from the treated cores showed biofilm formation on the rock pore surfaces, which is responsible for rock surface wettability alteration. PMID:23376749

  15. Biodegradation of s-triazine herbicide atrazine by Enterobacter cloacae and Burkholderia cepacia sp. from long-term treated sugarcane-cultivated soils in Kenya.

    PubMed

    Ngigi, Anastasiah N; Getenga, Zachary M; Boga, Hamadi I; Ndalut, Paul K

    2012-09-01

    In this study soils from sugarcane-cultivated fields were screened for bacterial species capable of atrazine (6-chloro-N²-ethyl-N⁴-isopropyl-1,3,5-triazine-2,4-diamine) degradation due to long exposure of the soils to this herbicide. To enrich for atrazine degraders, Minimal Salt Medium containing atrazine as the sole N source and glucose as the C source was inoculated with soils impacted with this herbicide and incubated. Bacterial growth was monitored by measuring optical density. The degradation of atrazine was followed by measuring residual atrazine in liquid cultures over a given time period by high performance liquid chromatography. Bacterial strains isolated from the enrichment cultures were characterized by biochemical tests and identified by 16S rRNA gene sequencing. Two bacterial strains coded ISL 8 and ISL 15 isolated from two different fields were shown to have 94 and 96% 16S rRNA gene sequence similarity to Burkholderia cepacia respectively. Another bacterial sp., ISL 14 was closely related to Enterobacter cloacae with a 96% 16S rRNA gene sequence similarity. There was not much difference between the extents of atrazine degradation by the enrichment cultures with communities (79-82% applied amount) from which pure strains were isolated and the pure strains themselves in liquid cultures that showed a degradation of 53-83% of applied amount. The study showed existence of bacterial strains in different sugarcane-cultivated fields which can use atrazine as a nitrogen source. The bacterial strains isolated can be used to enhance the degradation of atrazine in contaminated soils where atrazine is still considered to be recalcitrant. PMID:22575004

  16. Steady-state kinetics of the binding of beta-lactams and penicilloates to the second binding site of the Enterobacter cloacae P99 beta-lactamase.

    PubMed

    Dryjanski, M; Pratt, R F

    1995-03-21

    Previous research has shown that the class C beta-lactamase of Enterobacter cloacae P99 is able to catalyze the hydrolysis and aminolysis of acyclic depsipeptides. The steady kinetics of these reactions are complicated by the presence of an additional (depsi)peptide binding site in addition to the active site [Pazhanisamy, S., & Pratt, R. F. (1989) Biochemistry 28, 6875-6882]. The present paper presents a steady-state kinetic analysis of the inhibition of depsipeptide hydrolysis by sodium benzylpenicilloate, methyl benzylpenicilloate, 6-aminopenicillanic acid, and 7-aminocephalosporanic acid. The two beta-lactams are considerably poorer substrates than the depsipeptide employed, m-[[(phenylacetyl)glycyl]oxy]benzoic acid. The aim was to determine the relative affinity of these ligands for the active site and the second site. Three types of experiments were employed: (i) measurements of direct inhibition of depsipeptide hydrolysis, (ii) measurements of the effect of an active-site-directed inhibitor, m-(dansylamidophenyl)-boronic acid, on the effectiveness of the ligands as inhibitors, and (iii) measurements of the effect of a preferential second site ligand, N-(phenylacetyl)glycyl-D-phenylalanine, on the effectiveness of the ligands as inhibitors. The results suggest that all four ligands preferentially bind to the active site, with weaker binding at the second site. The necessarily weaker binding of a ligand to the second site when the active site is occupied by a transition-state analog inhibitor was analyzed. Perhaps surprisingly, the intact beta-lactams appeared to bind more firmly to the alternative site than do the flexible penicilloates.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7893652

  17. Reduction of Selenium Oxyanions by Enterobacter cloacae SLD1a-1: Isolation and Growth of the Bacterium and Its Expulsion of Selenium Particles

    PubMed Central

    Losi, M. E.; Frankenberger, W. T.

    1997-01-01

    A facultative bacterium capable of removing the selenium (Se) oxyanions selenate (SeO(inf4)(sup2-)) and selenite (SeO(inf3)(sup2-)) from solution culture in flasks open to the atmosphere was isolated and studied with the goal of assessing its potential for use in bioremediation of seleniferous agricultural drainage water. Elemental Se (Se(sup0)) was confirmed as a product of the reaction. The organism, identified as Enterobacter cloacae and designated strain SLD1a-1 (ATCC 700258), removed from 61.5 to 94.5% of added SeO(inf4)(sup2-) (the primary species present in agricultural drainage water) at concentrations from 13 to 1,266 (mu)M. Equimolar amounts of nitrate (NO(inf3)(sup-)), which interferes with SeO(inf4)(sup2-) reduction in some organisms, did not influence the reaction in growth experiments but had a slight inhibitory effect in a washed-cell suspension. Washed-cell suspension experiments also showed that (i) SeO(inf3)(sup2-) is a transitory intermediate in reduction of SeO(inf4)(sup2-), being produced and rapidly reduced concomitantly; (ii) NO(inf3)(sup-) is also reduced concomitantly and at a much higher rate than SeO(inf4)(sup2-); and (iii) although enzymatic, reduction of either oxyanion does not appear to be an inducible process. Transmission electron microscopy revealed that precipitate particles are <0.1 (mu)m in diameter, and these particles were observed free in the medium. Evidence indicates that SLD1a-1 uses SeO(inf4)(sup2-) as an alternate electron acceptor and that the reaction occurs via a membrane-associated reductase(s) followed by rapid expulsion of the Se particles. PMID:16535668

  18. Resolution of Distinct Membrane-Bound Enzymes from Enterobacter cloacae SLD1a-1 That Are Responsible for Selective Reduction of Nitrate and Selenate Oxyanions

    PubMed Central

    Ridley, Helen; Watts, Carys A.; Richardson, David J.; Butler, Clive S.

    2006-01-01

    Enterobacter cloacae SLD1a-1 is capable of reductive detoxification of selenate to elemental selenium under aerobic growth conditions. The initial reductive step is the two-electron reduction of selenate to selenite and is catalyzed by a molybdenum-dependent enzyme demonstrated previously to be located in the cytoplasmic membrane, with its active site facing the periplasmic compartment (C. A. Watts, H. Ridley, K. L. Condie, J. T. Leaver, D. J. Richardson, and C. S. Butler, FEMS Microbiol. Lett. 228:273-279, 2003). This study describes the purification of two distinct membrane-bound enzymes that reduce either nitrate or selenate oxyanions. The nitrate reductase is typical of the NAR-type family, with α and β subunits of 140 kDa and 58 kDa, respectively. It is expressed predominantly under anaerobic conditions in the presence of nitrate, and while it readily reduces chlorate, it displays no selenate reductase activity in vitro. The selenate reductase is expressed under aerobic conditions and expressed poorly during anaerobic growth on nitrate. The enzyme is a heterotrimeric (αβγ) complex with an apparent molecular mass of ∼600 kDa. The individual subunit sizes are ∼100 kDa (α), ∼55 kDa (β), and ∼36 kDa (γ), with a predicted overall subunit composition of α3β3γ3. The selenate reductase contains molybdenum, heme, and nonheme iron as prosthetic constituents. Electronic absorption spectroscopy reveals the presence of a b-type cytochrome in the active complex. The apparent Km for selenate was determined to be ∼2 mM, with an observed Vmax of 500 nmol SeO42− min−1 mg−1 (kcat, ∼5.0 s−1). The enzyme also displays activity towards chlorate and bromate but has no nitrate reductase activity. These studies report the first purification and characterization of a membrane-bound selenate reductase. PMID:16885262

  19. Reduction of aliphatic nitroesters and N-nitramines by Enterobacter cloacae PB2 pentaerythritol tetranitrate reductase: quantitative structure-activity relationships.

    PubMed

    Nivinskas, Henrikas; Sarlauskas, Jonas; Anusevicius, Zilvinas; Toogood, Helen S; Scrutton, Nigel S; Cenas, Narimantas

    2008-12-01

    Enterobacter cloacae PB2 NADPH:pentaerythritol tetranitrate reductase (PETNR) performs the biodegradation of explosive organic nitrate esters via their reductive denitration. In order to understand the enzyme substrate specificity, we have examined the reactions of PETNR with organic nitrates (n = 15) and their nitrogen analogues, N-nitramines (n = 4). The reactions of these compounds with PETNR were accompanied by the release of 1-2 mol of nitrite per mole of compound, but were not accompanied by their redox cycling and superoxide formation. The reduction rate constants (k(cat)/K(m)) of inositol hexanitrate, diglycerol tetranitrate, erythritol tetranitrate, mannitol hexanitrate and xylitol pentanitrate were similar to those of the established PETNR substrates, PETN and glycerol trinitrate, whereas the reactivities of hexahydro-1,3,5-trinitro-1,3,5-triazine and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine were three orders of magnitude lower. The log k(cat)/K(m) value of the compounds increased with a decrease in the enthalpy of formation of the hydride adducts [DeltaH(f)(R-O-N(OH)O(-)) or DeltaH(f)(R(1),R(2) > N-N(OH)O(-))], and with an increase in their lipophilicity (octanol/water partition coefficient, log P(ow)), and did not depend on their van der Waals' volumes. Hydrophobic organic nitroesters and hydrophilic N-nitramines compete for the same binding site in the reduced enzyme form. The role of the hydrophobic interaction of PETNR with glycerol trinitrate was supported by the positive dependence of glycerol trinitrate reactivity on the solution ionic strength. The discrimination of nitroesters and N-nitramines according to their log P(ow) values seems to be a specific feature of the Old Yellow Enzyme family of flavoenzymes. PMID:19016851

  20. Spread of Enterobacter cloacae carrying blaNDM-1, blaCTX-M-15, blaSHV-12 and plasmid-mediated quinolone resistance genes in a surgical intensive care unit in Croatia.

    PubMed

    Petrosillo, N; Vranić-Ladavac, M; Feudi, C; Villa, L; Fortini, D; Barišić, N; Bedenić, B; Ladavac, R; D'Arezzo, S; Andrašević, A Tambić; Capone, A

    2016-03-01

    The objective of this study was to describe a hospital cluster of NDM-1-producing Enterobacter cloacae infections observed in the surgical intensive care unit (ICU) of a tertiary-care hospital at Pula, Croatia. NDM-1-producing E. cloacae strains isolated from clinical samples were screened by PCR for the presence of carbapenemases. Genetic relatedness of NDM-1-producing E. cloacae strains was determined by multilocus sequence typing (MLST). During the period October 2013 to April 2014, four patients, with overlapping hospital stay in the surgical ICU, developed severe infections caused by E. cloacae demonstrated to produce carbapenemases. According to MLST, all strains belonged to ST133 and were positive by PCR for the blaNDM-1 carbapenemase gene, for blaCTX-M-15 and blaSHV-12 extended-spectrum β-lactamase (ESBL) genes, and for blaTEM-1 and blaOXA-1 narrow-spectrum β-lactamase genes. They were negative for other carbapenemases genes including blaOXA-48, blaVIM and blaKPC as well as for AmpC and the armA and rmtB aminoglycoside resistance genes. All strains were positive for the HI2 replicon, suggesting that an IncHI2 plasmid is likely the plasmid carrying the blaNDM-1 gene. Infection control measures were implemented after the first case although they were not effective in avoiding spread of this organism to other patients in the surgical ICU. In conclusion, the evolving epidemiology of NDM-producing micro-organisms and the interspecies diffusion of this resistance mechanism to emerging pathogens such as E. cloacae necessitate the setting up of strong and urgent joint measures to control the spread of NDM carbapenemase especially in the ICU setting. PMID:27436392

  1. Purification and Characterization of Glutaminase Free Asparaginase from Enterobacter cloacae: In-Vitro Evaluation of Cytotoxic Potential against Human Myeloid Leukemia HL-60 Cells.

    PubMed

    Husain, Islam; Sharma, Anjana; Kumar, Suresh; Malik, Fayaz

    2016-01-01

    Asparaginase is an important antileukemic agent extensively used worldwide but the intrinsic glutaminase activity of this enzymatic drug is responsible for serious life threatening side effects. Hence, glutaminase free asparaginase is much needed for upgradation of therapeutic index of asparaginase therapy. In the present study, glutaminase free asparaginase produced from Enterobacter cloacae was purified to apparent homogeneity. The purified enzyme was found to be homodimer of approximately 106 kDa with monomeric size of approximately 52 kDa and pI 4.5. Purified enzyme showed optimum activity between pH 7-8 and temperature 35-40°C, which is close to the internal environment of human body. Monovalent cations such as Na+ and K+ enhanced asparaginase activity whereas divalent and trivalent cations, Ca2+, Mg2+, Zn2+, Mn2+, and Fe3+ inhibited the enzyme activity. Kinetic parameters Km, Vmax and Kcat of purified enzyme were found to be 1.58×10-3 M, 2.22 IU μg-1 and 5.3 × 104 S-1, respectively. Purified enzyme showed prolonged in vitro serum (T1/2 = ~ 39 h) and trypsin (T1/2 = ~ 32 min) half life, which is therapeutically remarkable feature. The cytotoxic activity of enzyme was examined against a panel of human cancer cell lines, HL-60, MOLT-4, MDA-MB-231 and T47D, and highest cytotoxicity observed against HL-60 cells (IC50 ~ 3.1 IU ml-1), which was comparable to commercial asparaginase. Cell and nuclear morphological studies of HL-60 cells showed that on treatment with purified asparaginase symptoms of apoptosis were increased in dose dependent manner. Cell cycle progression analysis indicates that enzyme induces apoptosis by cell cycle arrest in G0/G1 phase. Mitochondrial membrane potential loss showed that enzyme also triggers the mitochondrial pathway of apoptosis. Furthermore, the enzyme was found to be nontoxic for human noncancerous cells FR-2 and nonhemolytic for human erythrocytes. PMID:26891220

  2. Purification and Characterization of Glutaminase Free Asparaginase from Enterobacter cloacae: In-Vitro Evaluation of Cytotoxic Potential against Human Myeloid Leukemia HL-60 Cells

    PubMed Central

    Husain, Islam; Sharma, Anjana; Kumar, Suresh; Malik, Fayaz

    2016-01-01

    Asparaginase is an important antileukemic agent extensively used worldwide but the intrinsic glutaminase activity of this enzymatic drug is responsible for serious life threatening side effects. Hence, glutaminase free asparaginase is much needed for upgradation of therapeutic index of asparaginase therapy. In the present study, glutaminase free asparaginase produced from Enterobacter cloacae was purified to apparent homogeneity. The purified enzyme was found to be homodimer of approximately 106 kDa with monomeric size of approximately 52 kDa and pI 4.5. Purified enzyme showed optimum activity between pH 7–8 and temperature 35–40°C, which is close to the internal environment of human body. Monovalent cations such as Na+ and K+ enhanced asparaginase activity whereas divalent and trivalent cations, Ca2+, Mg2+, Zn2+, Mn2+, and Fe3+ inhibited the enzyme activity. Kinetic parameters Km, Vmax and Kcat of purified enzyme were found to be 1.58×10−3 M, 2.22 IU μg-1 and 5.3 × 104 S-1, respectively. Purified enzyme showed prolonged in vitro serum (T1/2 = ~ 39 h) and trypsin (T1/2 = ~ 32 min) half life, which is therapeutically remarkable feature. The cytotoxic activity of enzyme was examined against a panel of human cancer cell lines, HL-60, MOLT-4, MDA-MB-231 and T47D, and highest cytotoxicity observed against HL-60 cells (IC50 ~ 3.1 IU ml-1), which was comparable to commercial asparaginase. Cell and nuclear morphological studies of HL-60 cells showed that on treatment with purified asparaginase symptoms of apoptosis were increased in dose dependent manner. Cell cycle progression analysis indicates that enzyme induces apoptosis by cell cycle arrest in G0/G1 phase. Mitochondrial membrane potential loss showed that enzyme also triggers the mitochondrial pathway of apoptosis. Furthermore, the enzyme was found to be nontoxic for human noncancerous cells FR-2 and nonhemolytic for human erythrocytes. PMID:26891220

  3. Crystallographic structure of a phosphonate derivative of the Enterobacter cloacae P99 cephalosporinase: mechanistic interpretation of a beta-lactamase transition-state analog.

    PubMed

    Lobkovsky, E; Billings, E M; Moews, P C; Rahil, J; Pratt, R F; Knox, J R

    1994-06-01

    The crystal structure of a complex formed on reaction of the Enterobacter cloacae P99 cephalosporinase (beta-lactamase) with a phosphonate monoester inhibitor, m-carboxyphenyl [[N-[(p-iodophenyl)acetyl]amino]methyl]phosphonate, has been obtained at 2.3-A resolution. The structure shows that the inhibitor has phosphonylated the active site serine (Ser64) with loss of the m-carboxyphenol leaving group. The inhibitor is positioned in the active site in a way that can be interpreted in terms of a transition-state analog. The arylacetamido side chain is placed as anticipated from analogous beta-lactamoyl complexes of penicillin-recognizing enzymes, with the amino group hydrogen-bonded to the backbone carbonyl of Ser318 (of the B3 beta-strand) and to the amides of Gln120 and Asn152. There is support in the asymmetry of the hydrogen bonding of this side chain to the protein and in the 2-fold disorder of the benzyl group for the considerable breadth in substrate specificity exhibited by class C beta-lactamases. One phosphonyl oxygen atom is in the oxyanion hole, hydrogen-bonded to main-chain NH groups of Ser318 and Ser64, while the other oxygen is solvated, not within hydrogen-bonding distance of any amino acid side chain. The closest active site functional group to the solvated oxygen atom is the Tyr150 hydroxyl group (3.4A); Lys67 and Lys315 are quite distant (4.3 and 5.7 A, respectively). Rather, Tyr150 and Lys67 are more closely associated with Ser64O gamma (2.9 and 3.3 A). This arrangement is interpreted in terms of the transition state for breakdown of the tetrahedral intermediate in the deacylation step of catalysis, where the Tyr150 phenol seems the most likely general acid. Thus, Tyr150, as the phenoxide anion, would be the general base catalyst in acylation, as proposed by Oefner et al. [Nature (1990) 343, 284-288]. The structure is compared with that of a similar phosphonate derivative of a class A beta-lactamase [Chen et al. (1993) J. Mol. Biol. 234, 165

  4. MALDI-TOF MS as a Tool To Detect a Nosocomial Outbreak of Extended-Spectrum-β-Lactamase- and ArmA Methyltransferase-Producing Enterobacter cloacae Clinical Isolates in Algeria

    PubMed Central

    Khennouchi, Nour Chems el Houda; Loucif, Lotfi; Boutefnouchet, Nafissa; Allag, Hamoudi

    2015-01-01

    Enterobacter cloacae is among the most important pathogens responsible for nosocomial infections and outbreaks. In this study, 77 Enterobacter isolates were collected: 27 isolates from Algerian hospitals (in Constantine, Annaba, and Skikda) and 50 isolates from Marseille, France. All strains were identified by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). Antibiotic susceptibility testing was performed by the disk diffusion method. PCR was used to detect extended-spectrum-beta-lactamase (ESBL)-encoding, fluoroquinolone resistance-encoding, and aminoglycoside-modifying enzyme (AME) genes. Epidemiological typing was performed using MALDI-TOF MS with data mining approaches, along with multilocus sequence typing (MLST). Sixty-eight isolates (27 from Algeria, 41 from Marseille) were identified by MALDI-TOF MS as E. cloacae. Resistance to antibiotics in the Algerian isolates was significantly higher than that in the strains from Marseille, especially for beta-lactams and aminoglycosides. Eighteen of the 27 Algerian isolates and 11 of the 41 Marseille isolates possessed at least one ESBL-encoding gene: blaCTX-M and/or blaTEM. AME genes were detected in 20 of the 27 Algerian isolates and 8 of the 41 Marseille isolates [ant(2″)-Ia, aac(6′)-Ib-cr, aadA1, aadA2, and armA]. Conjugation experiments showed that armA was carried on a transferable plasmid. MALDI-TOF typing showed three separate clusters according to the geographical distribution and species level. An MLST-based phylogenetic tree showed a clade of 14 E. cloacae isolates from a urology unit clustering together in the MALDI-TOF dendrogram, suggesting the occurrence of an outbreak in this unit. In conclusion, the ability of MALDI-TOF to biotype strains was confirmed, and surveillance measures should be implemented, especially for Algerian patients hospitalized in France. PMID:26239991

  5. MALDI-TOF MS as a Tool To Detect a Nosocomial Outbreak of Extended-Spectrum-β-Lactamase- and ArmA Methyltransferase-Producing Enterobacter cloacae Clinical Isolates in Algeria.

    PubMed

    Khennouchi, Nour Chems el Houda; Loucif, Lotfi; Boutefnouchet, Nafissa; Allag, Hamoudi; Rolain, Jean-Marc

    2015-10-01

    Enterobacter cloacae is among the most important pathogens responsible for nosocomial infections and outbreaks. In this study, 77 Enterobacter isolates were collected: 27 isolates from Algerian hospitals (in Constantine, Annaba, and Skikda) and 50 isolates from Marseille, France. All strains were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Antibiotic susceptibility testing was performed by the disk diffusion method. PCR was used to detect extended-spectrum-beta-lactamase (ESBL)-encoding, fluoroquinolone resistance-encoding, and aminoglycoside-modifying enzyme (AME) genes. Epidemiological typing was performed using MALDI-TOF MS with data mining approaches, along with multilocus sequence typing (MLST). Sixty-eight isolates (27 from Algeria, 41 from Marseille) were identified by MALDI-TOF MS as E. cloacae. Resistance to antibiotics in the Algerian isolates was significantly higher than that in the strains from Marseille, especially for beta-lactams and aminoglycosides. Eighteen of the 27 Algerian isolates and 11 of the 41 Marseille isolates possessed at least one ESBL-encoding gene: blaCTX-M and/or blaTEM. AME genes were detected in 20 of the 27 Algerian isolates and 8 of the 41 Marseille isolates [ant(2″)-Ia, aac(6')-Ib-cr, aadA1, aadA2, and armA]. Conjugation experiments showed that armA was carried on a transferable plasmid. MALDI-TOF typing showed three separate clusters according to the geographical distribution and species level. An MLST-based phylogenetic tree showed a clade of 14 E. cloacae isolates from a urology unit clustering together in the MALDI-TOF dendrogram, suggesting the occurrence of an outbreak in this unit. In conclusion, the ability of MALDI-TOF to biotype strains was confirmed, and surveillance measures should be implemented, especially for Algerian patients hospitalized in France. PMID:26239991

  6. Mutational Enzymatic Resistance of Enterobacter Species to Beta-Lactam Antibiotics

    PubMed Central

    Lampe, Mary F.; Allan, Barbara J.; Minshew, Barbara H.; Sherris, John C.

    1982-01-01

    Mutants with enhanced β-lactam resistance were selected from strains of Enterobacter cloacae and E. aerogenes by using three antibiotics. High-level β-lactamase-producing mutants had similar degrees of increased resistance, enzyme substrate profiles, and isoelectric (pI) values irrespective of the selective agent. Reverse mutants from a resistant E. cloacae mutant regained the susceptibility pattern originally exhibited by the wild type, or were of enhanced susceptibility, and no longer expressed increased β-lactamase production. β-Lactamases of the mutants were similar in pI values to the wild-type enzyme. The increased resistance of the mutants therefore appeared to be accounted for by increased β-lactamase production. Images PMID:6979311

  7. Modification of rock/fluid and fluid/fluid interfaces during MEOR processes, using two biosurfactant producing strains of Bacillus stearothermophilus SUCPM#14 and Enterobacter cloacae: a mechanistic study.

    PubMed

    Sarafzadeh, Pegah; Zeinolabedini Hezave, Ali; Mohammadi, Sahar; Niazi, Ali; Ayatollahi, Shahab

    2014-05-01

    During any microbial enhanced oil recovery process, both cells and the metabolic products of bacteria govern the tertiary oil recovery efficiency. However, very accurate examination is needed to find the functionality of these tiny creatures at different reservoir conditions. In this regard, the effect of cell structure on ultimate microbial recovery efficiency which is the most dominant mechanism based on the microorganism types (gram-negative or gram-positive) was systematically investigated. At the first stage, possible different active mechanisms using Bacillus stearothermophilus SUCPM#14 strain were tested using specially designed injection protocol, in situ and ex situ core flooding experiments, interfacial tension, viscosity, pH and Amott wettability index measurements. At the second stage, comparing functionality of B. stearothermophilus SUCPM#14 (a gram-positive type) with the previously examined strain namely Enterobacter cloacae as a gram-negative type, proposed this hypothesis that the cell structure significantly affects the interfacial behaviors. New designed protocols were utilized to check the individual effects of cells, bioproducts and interaction of these together on the oil/water and also fluids/rock interfaces. The final results showed that the cells of B. stearothermophilus SUCPM#14 adhere more into the oil/water interface compared to E. cloacae and change its rheological properties; e.g. its elastic properties which affect the ultimate microbial oil recovery efficiency. Eventually, contradicting results revealed that biosurfactant produced by E. cloacae was able to considerably reduce the interfacial tension and alter the wettability of the rock (to neutral conditions) while biosurfactant produced by B. stearothermophilus SUCPM#14 was not very effective. PMID:24373916

  8. Complete genome of the switchgrass endophyte Enterobacter clocace P101

    PubMed Central

    Humann, Jodi L.; Wildung, Mark; Pouchnik, Derek; Bates, Austin A.; Drew, Jennifer C.; Zipperer, Ursula N.; Triplett, Eric W.; Main, Dorrie; Schroeder, Brenda K.

    2014-01-01

    The Enterobacter cloacae complex is genetically very diverse. The increasing number of complete genomic sequences of E. cloacae is helping to determine the exact relationship among members of the complex. E. cloacae P101 is an endophyte of switchgrass (Panicum virgatum) and is closely related to other E. cloacae strains isolated from plants. The P101 genome consists of a 5,369,929 bp chromosome. The chromosome has 5,164 protein-coding regions, 100 tRNA sequences, and 8 rRNA operons. PMID:25197457

  9. Serine utilization by Klebsiella aerogenes.

    PubMed Central

    Vining, L C; Magasanik, B

    1981-01-01

    Klebsiella aerogenes was found to contain a specific L-serine dehydrase that was induced by threonine, glycine or leucine, but not by its substrate. Cellular concentrations were sensitive to carbon rather than nitrogen sources in the growth medium. A nonspecific isoleucine-sensitive L-threonine dehydrase supplemented the specific L-serine dehydrase activity. K. aerogenes also contains a leucine-inducible L-threonine dehydrogenase which probably initiated a threonine-utilization pathway in which the serine-specific dehydrate participated. Strains that were altered in their ability to metabolize serine differed in either L-serine dehydrase or L-threonine dehydrase activity. Thus, K. aerogenes growing on L-serine as a sole nitrogen source relies upon two enzymes that metabolize the amino acid as subsidiary functions. PMID:6783624

  10. Phage-mediated Shiga toxin (Stx) horizontal gene transfer and expression in non-Shiga toxigenic Enterobacter and Escherichia. coli strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    M12X01451, an Enterobacter cloacae strain recently identified from a clinical specimen, produces a new Stx1e that was not neutralized by existing anti-Stx1 monoclonal antibodies. Acquisition of stx by Ent. cloacae is rare and information regarding the origin and stability of the stx1e in M12X01451 i...

  11. Phage-mediated Shiga toxin (Stx) horizontal gene transfer and expression in non-Shiga toxigenic Enterobacter and Escherichia coli strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    M12X01451, an Enterobacter cloacae strain recently identified from a clinical specimen, produces a new Stx1e that was not neutralized by existing anti-Stx1 monoclonal antibodies. Acquisition of stx by Ent. cloacae is rare and information regarding the origin and stability of the stx1e in M12X01451 i...

  12. Atypical internal yellowing of papaya fruit in Hawaii caused by Enterobacter sakazakii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Internal yellowing (IY), characterized by yellow discolored tissue around the papaya (Carica papaya) seed cavity, diffuse margins and the presence of a distinctly rotten odor, was first reported in 1987. These symptoms were associated with the causal agent Enterobacter cloacae. Here we report the fo...

  13. Enterobacter asburiae sp. nov., a new species found in clinical specimens, and reassignment of Erwinia dissolvens and Erwinia nimipressuralis to the genus Enterobacter as Enterobacter dissolvens comb. nov. and Enterobacter nimipressuralis comb. nov.

    PubMed Central

    Brenner, D J; McWhorter, A C; Kai, A; Steigerwalt, A G; Farmer, J J

    1986-01-01

    Enterobacter asburiae sp. nov. is a new species that was formerly referred to as Enteric Group 17 and that consists of 71 strains, 70 of which were isolated from humans. Enterobacter asburiae sp. nov. strains gave positive reactions in tests for methyl red, citrate utilization (Simmons and Christensen's), urea hydrolysis, L-ornithine decarboxylase, growth in KCN, acid and gas production from D-glucose, and acid production from L-arabinose, cellobiose, glycerol (negative in 1 to 2 days, positive in 3 to 7 days), lactose, D-mannitol, alpha-methyl-D-glucoside, salicin, D-sorbitol, sucrose, trehalose, and D-xylose. They gave negative reactions in the Voges-Proskauer test and in tests for indole, H2S production, phenylalanine, L-lysine decarboxylase, motility, gelatin, utilization of malonate, lipase, DNase, tyrosine clearing, acid production from adonitol, D-arabitol, dulcitol, erythritol, i(myo)-inositol, melibiose, and L-rhamnose. They gave variable reactions in tests for L-arginine dihydrolase (25% positive after 2 days) and acid production from raffinose (69% positive after 2 days). Thirty-four Enterobacter asburiae sp. nov. strains were tested for DNA relatedness by the hydroxyapatite method with 32PO4-labeled DNA from the designated type strain (1497-78, ATCC 35953). The strains were 69 to 100% related in 60 degrees C reactions and 63 to 100% related in 75 degrees C reactions. Divergence within related sequences was 0 to 2.5%. Relatedness of Enterobacter asburiae sp. nov. to 84 strains of members of the Enterobacteriaceae was 5 to 63%, with closest relatedness to strains of Enterobacter cloacae, Erwinia dissolvens, Enterobacter taylorae, Enterobacter agglomerans, Erwinia nimipressuralis, and Enterobacter gergoviae. All strains tested were susceptible to gentamicin and sulfdiazine, and most were susceptible to chloramphenicol, colistin, kanamycin, nalidixic acid, carbenicillin and streptomycin. All strains were resistant to ampicillan, cephalothin, and penicillin

  14. Enterobacter asburiae sp. nov., a new species found in clinical specimens, and reassignment of Erwinia dissolvens and Erwinia nimipressuralis to the genus Enterobacter as Enterobacter dissolvens comb. nov. and Enterobacter nimipressuralis comb. nov.

    PubMed

    Brenner, D J; McWhorter, A C; Kai, A; Steigerwalt, A G; Farmer, J J

    1986-06-01

    Enterobacter asburiae sp. nov. is a new species that was formerly referred to as Enteric Group 17 and that consists of 71 strains, 70 of which were isolated from humans. Enterobacter asburiae sp. nov. strains gave positive reactions in tests for methyl red, citrate utilization (Simmons and Christensen's), urea hydrolysis, L-ornithine decarboxylase, growth in KCN, acid and gas production from D-glucose, and acid production from L-arabinose, cellobiose, glycerol (negative in 1 to 2 days, positive in 3 to 7 days), lactose, D-mannitol, alpha-methyl-D-glucoside, salicin, D-sorbitol, sucrose, trehalose, and D-xylose. They gave negative reactions in the Voges-Proskauer test and in tests for indole, H2S production, phenylalanine, L-lysine decarboxylase, motility, gelatin, utilization of malonate, lipase, DNase, tyrosine clearing, acid production from adonitol, D-arabitol, dulcitol, erythritol, i(myo)-inositol, melibiose, and L-rhamnose. They gave variable reactions in tests for L-arginine dihydrolase (25% positive after 2 days) and acid production from raffinose (69% positive after 2 days). Thirty-four Enterobacter asburiae sp. nov. strains were tested for DNA relatedness by the hydroxyapatite method with 32PO4-labeled DNA from the designated type strain (1497-78, ATCC 35953). The strains were 69 to 100% related in 60 degrees C reactions and 63 to 100% related in 75 degrees C reactions. Divergence within related sequences was 0 to 2.5%. Relatedness of Enterobacter asburiae sp. nov. to 84 strains of members of the Enterobacteriaceae was 5 to 63%, with closest relatedness to strains of Enterobacter cloacae, Erwinia dissolvens, Enterobacter taylorae, Enterobacter agglomerans, Erwinia nimipressuralis, and Enterobacter gergoviae. All strains tested were susceptible to gentamicin and sulfdiazine, and most were susceptible to chloramphenicol, colistin, kanamycin, nalidixic acid, carbenicillin and streptomycin. All strains were resistant to ampicillan, cephalothin, and penicillin

  15. Use of microdilution panels with and without beta-lactamase inhibitors as a phenotypic test for beta-lactamase production among Escherichia coli, Klebsiella spp., Enterobacter spp., Citrobacter freundii, and Serratia marcescens.

    PubMed

    Thomson, K S; Sanders, C C; Moland, E S

    1999-06-01

    Over the past decade, a number of new beta-lactamases have appeared in clinical isolates of Enterobacteriaceae that, unlike their predecessors, do not confer beta-lactam resistance that is readily detected in routine antibiotic susceptibility tests. Because optimal methodologies are needed to detect these important new beta-lactamases, a study was designed to evaluate the ability of a panel of various beta-lactam antibiotics tested alone and in combination with beta-lactamase inhibitors to discriminate between the production of extended-spectrum beta-lactamases, AmpC beta-lactamases, high levels of K1 beta-lactamase, and other beta-lactamases in 141 isolates of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Enterobacter aerogenes, Citrobacter freundii, and Serratia marcescens possessing well-characterized beta-lactamases. The microdilution panels studied contained aztreonam, cefpodoxime, ceftazidime, cefotaxime, and ceftriaxone, with and without 1, 2, and 4 microg of clavulanate per ml or 8 microg of sulbactam per ml and cefoxitin and cefotetan with and without 8 microg of sulbactam per ml. The results indicated that a minimum panel of five tests would provide maximum separation of extended-spectrum beta-lactamase high AmpC, high K1, and other beta-lactamase production in Enterobacteriaceae. These included cefpodoxime, cefpodoxime plus 4 microg of clavulanate per ml, ceftazidime, ceftriaxone, and ceftriaxone plus 8 microg of sulbactam per ml. Ceftriaxone plus 2 microg of clavulanate per ml could be substituted for cefpodoxime plus 4 microg of clavulanate per ml without altering the accuracy of the tests. This study indicated that tests with key beta-lactam drugs, alone and in combination with beta-lactamase inhibitors, could provide a convenient approach to the detection of a variety of beta-lactamases in members of the family Enterobacteriaceae. PMID:10348759

  16. Concomitant rock phosphate dissolution and lead immobilization by phosphate solubilizing bacteria (Enterobacter sp.).

    PubMed

    Park, Jin Hee; Bolan, Nanthi; Megharaj, Mallavarapu; Naidu, Ravi

    2011-04-01

    This paper examines the potential value of phosphate solubilizing bacteria (Enterobacter cloacae) in the dissolution of rock phosphate (RP) and subsequent immobilization of lead (Pb) in both bacterial growth medium and soils. Enterobacter sp. showed resistance to Pb and the bacterium solubilized 17.5% of RP in the growth medium. Enterobacter sp. did not enhance Pb immobilization in solution because of acidification of bacterial medium, thereby inhibiting the formation of P-induced Pb precipitation. However, in the case of soil, Enterobacter sp. increased Pb immobilization by 6.98, 25.6 and 32.0% with the RP level of 200, 800 and 1600 mg P/kg, respectively. The immobilization of Pb in Pb-spiked soils was attributed to pyromorphite formation as indicated by XRD analysis. Inoculation of phosphate solubilizing bacteria with RP in soil can be used as an alternative technique to soluble P compounds which can cause eutrophication of surface water. PMID:21190789

  17. Dechlorination of DDT by Aerobacter aerogenes

    USGS Publications Warehouse

    1966-01-01

    Dechlorination of DDT to DDD in higher animals requires the presence of molecular oxygen, but in microorganisms the presence of oxygen hinders dechlorination. In cell-free preparations of Aerobacter aerogenes, the use of selected metabolic inhibitors indicated that reduced Fe(II) cytochrome oxidase was responsible for DDT dechlorination. This finding may possibly explain. the persistence of DDT residues in soils and sediments.

  18. The aerogen-π bonds involving π systems

    NASA Astrophysics Data System (ADS)

    Gao, Meng; Cheng, Jianbo; Li, Wenzuo; Xiao, Bo; Li, Qingzhong

    2016-05-01

    Ab initio calculations have been performed to study the complexes of XeOF2 and a series of π systems including ethyne, ethene, benzene, pyrrole, furan, and thiophene. More than two structures were obtained for each complex with an aerogen-π bond. The configuration of complex has a significant effect on its stability. The strength of aerogen-π interaction is comparable with that of lone pair-aerogen interaction and conventional hydrogen bonds. A breakdown of the aerogen-π interaction attributes its stability to approximately equal parts electrostatic and polarization energies, with a relatively smaller contribution from dispersion energy.

  19. Pathology of cloaca anomalies with case correlation.

    PubMed

    Gupta, Anita; Bischoff, Andrea

    2016-04-01

    During the fourth week of human embryo development, a transient common channel known as a cloaca is formed from which three cavities with three external orifices arises. Cloaca anomalies occur when there is failure of separation of the rectum, vagina, and urethra channel resulting in a single drain into the perineum. In our previous institutional studies, Runck et al. compared human and mouse cloaca development and found early mis-patterning of the embryonic cloaca deranged hedgehog and bone morphogenetic proteins (BMP) signaling. Also, our group reported the embryological correlation of the epithelial and stromal histology found in step sections of the common channel in 14 cloaca malformations in humans. In this review, we present the pathology of a 4-year-old female with a cloaca and VACTERL complex, and summarize our current knowledge of cloaca pathology. Furthermore, we suggest that careful pathological examination of cloaca specimens in conjunction with surgical orientation may result in a better understanding of the etiology of this condition. PMID:26969228

  20. Ribitol Catabolic Pathway in Klebsiella aerogenes

    PubMed Central

    Charnetzky, W. T.; Mortlock, R. P.

    1974-01-01

    In Klebsiella aerogenes W70, there is an inducible pathway for the catabolism of ribitol consisting of at least two enzymes, ribitol dehydrogenase (RDH) and d-ribulokinase (DRK). These two enzymes are coordinately controlled and induced in response to d-ribulose, an intermediate of the pathway. Whereas wild-type K. aerogenes W70 are unable to utilize xylitol as a carbon and energy source, mutants constitutive for the ribitol pathway are able to utilize RDH to oxidize the unusual pentitol, xylitol, to d-xylulose. These mutants are able to grow on xylitol, presumably by utilization of the d-xylulose produced. Mutants constitutive for l-fucose isomerase can utilize the isomerase to convert d-arabinose to d-ribulose. In the presence of d-ribulose, RDH and DRK are induced, and such mutants are thus able to phosphorylate the d-ribulose by using the DRK of the ribitol pathway. Derivatives of an l-fucose isomerase-constitutive mutant were plated on d-arabinose, ribitol, and xylitol to select and identify mutations in the ribitol pathway. Using the transducing phage PW52, we were able to demonstrate genetic linkage of the loci involved. Three-point crosses, using constitutive mutants as donors and RDH−, DRK− double mutants as recipients and selecting for DRK+ transductants on d-arabinose, resulted in DRK+RDH+-constitutive, DRK+RDH+-inducible, and DRK+RDH−-inducible transductants but no detectable DRK+RDH− constitutive transductants, data consistent with the order rbtC-rbtD-rbtK, where rbtC is a control site and rbtD and rbtK correspond to the sites for the sites for the enzymes RDH and DRK, respectively. PMID:4366025

  1. Partial hydrolysis of dieldrin by Aerobacter aerogenes

    USGS Publications Warehouse

    Wedemeyer, G.

    1968-01-01

    Although dieldrin (1,2,3 ,4,10,10-hexachloro- 6,7-epoxy-1 ,4 ,4a ,5 ,6 ,7 ,8, 8a-octahydro-1 ,4-endo, exo-5, 8-dimethanonaphthalene) metabolism by mammals (F. Korte and H. Arent, Life Sci. 4:2017, 1965) and insects (D. F. Heath and M. Vanderkar, Brit. J. Ind. Med. 21:269, 1964) has been reported, little is known about the degradation of this important pesticide by microorganisms. Korte et al. (Ann. Chem. Liebigs 656:135, 1962) and Chacko et al. (Science 154: 893, 1966) reported that a number of ubiquitous microorganisms were incapable of degrading dieldrin; however, more recently Matsumura and Boush (Science 156:959, 1967) isolated several species of Pseudomonas and Bacillus which could degrade dieldrin, from a number of soil samples having similar activity. They did not specifically attempt to identify the dieldrin metabolites formed, but they did suggest, on the basis of an identical RF value with an authentic control that 6,7-trans-dihydroxydihydroaldrin (aldrin diol) might be a major product. Work carried out concurrently in this laboratory has shown that another ubiquitous bacterium, Aerobacter aerogenes, converts dieldrin in vitro to a compound chromatographically

  2. Enterobacter sepsis in infants and children due to contaminated intravenous fluids.

    PubMed

    Matsaniotis, N S; Syriopoulou, V P; Theodoridou, M C; Tzanetou, K G; Mostrou, G I

    1984-10-01

    Sixty-three cases of nosocomial sepsis occurring from April through October 1981, in a 500-bed pediatric hospital, were traced to bacterial contamination of intravenous fluid produced by a single manufacturer. Two species of uncommon blood stream pathogens, Enterobacter cloacae and Enterobacter agglomerans contaminated the fluid. Infections with these organisms might have contributed to the death of four patients; two who were immunosuppressed, one who was asplenic and one premature infant. Epidemiologic and laboratory investigations identified the site of contamination to be within the screw-caps of the bottles containing the intravenous fluid. Contamination occurred during insertion of the intravenous fluid administration set into the bottle. The "epidemic" terminated when the hospital discontinued the use of infusion fluids from that manufacturer. We conclude that intravenous fluids should be examined during outbreaks of nosocomial bacteremia due to unusual pathogens. PMID:6567611

  3. Occurrence and analysis of irp2 virulence gene in isolates of Klebsiella pneumoniae and Enterobacter spp. from microbiota and hospital and community-acquired infections.

    PubMed

    Souza Lopes, Ana Catarina; Rodrigues, Juliana Falcão; Cabral, Adriane Borges; da Silva, Maíra Espíndola; Leal, Nilma Cintra; da Silveira, Vera Magalhães; de Morais Júnior, Marcos Antônio

    2016-07-01

    Eighty-five isolates of Klebsiella pneumoniae and Enterobacter spp., originating from hospital- and community-acquired infections and from oropharyngeal and faecal microbiota from patients in Recife-PE, Brazil, were analyzed regarding the presence of irp2 gene. This is a Yersinia typical gene involved in the synthesis of siderophore yersiniabactin. DNA sequencing confirmed the identity of irp2 gene in five K. pneumoniae, five Enterobacter aerogenes and one Enterobacter amnigenus isolates. To our knowledge in the current literature, this is the first report of the irp2 gene in E. amnigenus, a species considered an unusual human pathogen, and in K. pneumoniae and E. aerogenes isolates from the normal microbiota and from community infections, respectively. Additionally, the analyses of nucleotide and amino acid sequences suggest the irp2 genes derived from isolates used in this study are more closely related to that of Yersinia pestis P.CE882 than to that of Yersinia enterocolitica 8081. These data demonstrated that K. pneumoniae and Enterobacter spp. from normal microbiota and from community- and hospital-acquired infections possess virulence factors important for the establishment of extra-intestinal infections. PMID:27133266

  4. Sequence and properties of pentaerythritol tetranitrate reductase from Enterobacter cloacae PB2.

    PubMed Central

    French, C E; Nicklin, S; Bruce, N C

    1996-01-01

    Pentaerythritol tetranitrate reductase, which reductively liberates nitrite from nitrate esters, is related to old yellow enzyme. Pentaerythritol tetranitrate reductase follows a ping-pong mechanism with competitive substrate inhibition by NADPH, is strongly inhibited by steroids, and is capable of reducing the unsaturated bond of 2-cyclohexen-1-one. PMID:8932320

  5. Group IIC Intron with an Unusual Target of Integration in Enterobacter cloacae

    PubMed Central

    Rodríguez-Martínez, José-Manuel; Poirel, Laurent

    2012-01-01

    A potential role of group IIC-attC introns in integron gene cassette formation, that is, the way in which they could provide the attC sequence essential for recombination, has been proposed. Group IIC introns usually target the attC site of gene cassettes and more specifically their inverse core. Here we characterized a novel group IIC intron targeting the core site of the aadA1 gene cassette attC site (aadA1-qacEΔ1 gene cassette junction) from enterobacterial isolates. Intron mobility (retrohoming) was analyzed using a two-plasmid assay performed in Escherichia coli. Intron mobility assays confirmed the mobilization-integration of the group II intron into the core site of the aadA2, blaVIM-2, blaCARB-2, aac(6′)-Ib, dfrXVb, arr2, cmlA4, and aadB gene cassettes but not into the attI site. This mobility was dependent on maturase activity. Reverse transcriptase PCR showed that this intron was transcriptionally active, and an intermediate circular form was detected by inverse PCR. This element was linked to the blaVEB-1 extended-spectrum β-lactamase gene in a high number of enterobacterial isolates. A phylogenetic tree showed that the identified element was located in a branch separate from group IIC-attC introns, being an IIC intron possessing the ability to integrate using the core site of the attC sites as target. PMID:22020643

  6. COLONIZATION OF SUBTERRANEAN PLANT SURFACES AND SUPPRESSION OF SOILBORNE PLANT PATHOGENS: STUDIES WITH ENTEROBACTER CLOACAE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is generally assumed that biocontrol organisms must colonize subterranean plant parts for effective suppression of soilborne plant pathogens in many biocontrol interactions. Unfortunately our knowledge of the processes that lead to effective colonization is unclear. Also unclear is our knowledg...

  7. Influence of host seed on metabolic activity by Enterobacter cloacae in the spermosphere

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known regarding the influences of nutrients released from plants on the metabolic activity of colonizing microbes. To gain a better understanding of these influences, we used bioluminescence- and oxygen consumption-based methods to compare bacterial metabolic activity expressed during col...

  8. Dry stress and survival time of Enterobacter sakazakii and other Enterobacteriaceae in dehydrated powdered infant formula.

    PubMed

    Barron, Juncal Caubilla; Forsythe, Stephen J

    2007-09-01

    Powdered infant formula is not a sterile product, and opportunistic pathogens could multiply in the reconstituted product, resulting in neonatal infections. In this study, the generation of sublethally injured Enterobacteriaceae during desiccation and their persistence in dehydrated powdered infant formula was assessed during a 2.5-year period. The study included 27 strains of Enterobacter sakazakii, Enterobacter cloacae, Salmonella Enteritidis, Citrobacter koseri, Citrobacter freundii, Escherichia coli, Escherichia vulneris, Pantoea spp., Klebsiella oxytoca, and Klebsiella pneumoniae. The number of sublethally injured cells generated during desiccation was lower for K. oxytoca, Pantoea spp., Salmonella Enteritidis, and capsulated strains of E. sakazakii than for the other Enterobacteriaceae. The Enterobacteriaceae could be divided into three groups with respect to their long-term survival in the desiccated state. C. freundii, C. koseri, and E. cloacae were no longer recoverable after 6 months, and Salmonella Enteritidis, K. pneumoniae, and E. coli could not be recovered after 15 months. Pantoea spp., K. oxytoca, and E. vulneris persisted over 2 years, and some capsulated strains of E. sakazakii were still recoverable after 2.5 years. PMID:17900090

  9. Enterobacter hormaechei, a new species of the family Enterobacteriaceae formerly known as enteric group 75.

    PubMed

    O'Hara, C M; Steigerwalt, A G; Hill, B C; Farmer, J J; Fanning, G R; Brenner, D J

    1989-09-01

    The name Enterobacter hormaechei is proposed for a new species of the family Enterobacteriaceae, formerly called Enteric Group 75, which consists of 23 strains, 22 of which were isolated from humans. DNAs from 12 E. hormaechei strains tested were highly related to the type strain (ATCC 49162) by DNA hybridization, using the hydroxyapatite method (80 to 97% in 60 degrees C reactions; 80 to 90% in 75 degrees C reactions). The strains were most closely related (50 to 63%) to Enterobacter cloacae, Enterobacter dissolvens, Enterobacter taylorae, and Enterobacter nimipressuralis. E. hormaechei strains were positive within 48 h for the following: Voges-Proskauer test; citrate utilization (Simmons and Christensen); urea hydrolysis (87%); ornithine decarboxylase; growth in potassium cyanide (KCN); malonate utilization; production of acid from D-glucose, L-arabinose, cellobiose, dulcitol (87%), D-galactose, maltose, D-mannitol, D-mannose, L-rhamnose, sucrose, trehalose, and D-xylose; acid production from mucate; nitrate reduction; and o-nitrophenyl-beta-D-galactopyranoside. Delayed positive reactions were seen in tests for arginine dihydrolase, gas from D-glucose, acid from alpha-methyl-D-glucoside, and acetate utilization. E. hormaechei was negative in tests for indole production; H2S production; phenylalanine deaminase; lysine decarboxylase; gelatin hydrolysis; acid production from D-adonitol, D-arabitol, erythritol, glycerol, i(myo)-inositol, melibiose, raffinose, and D-sorbitol; esculin hydrolysis; DNase; lipase; and tyrosine clearing. Variable reactions occurred in tests for methyl red, motility, and tartrate. All strains tested were susceptible or moderately susceptible to amikacin, azlocillin, cefotaxime, ceftazidime, ceftriaxone, chloramphenicol, gentamicin, mezlocillin, moxalactam, piperacillin, trimethoprim-sulfamethoxazole, sulfisoxazole, thienamycin, tobramycin, and trimethoprim. All strains tested were resistant to nitrofurantoin; the majority were resistant to

  10. Single-electron aerogen bonds: Do they exist?

    NASA Astrophysics Data System (ADS)

    Esrafili, Mehdi D.; Mohammadian-Sabet, Fariba; Solimannejad, Mohammad

    2016-08-01

    A novel type of σ-hole interaction is characterized between some noble gas containing molecules (KrOF2, KrO3, XeOF2 and XeO3) and methyl (CH3) or ethyl (C2H5) radical by means of ab initio calculations. This interaction is named as single-electron aerogen bond (SEAB), in view of the concepts of aerogen bond and single-electron bond interactions. The properties of SEABs are studied by molecular electrostatic potential, quantum theory of atom in molecules, natural bonding orbital and noncovalent interaction index analyses. The formation of an O⋯H interaction tends to increase the strength of the SEAB, when they coexist in a ternary complex.

  11. Study of bio-degradation and bio-decolourization of azo dye by Enterobacter sp. SXCR.

    PubMed

    Prasad, Shiv Shankar; Aikat, Kaustav

    2014-01-01

    The objective of this study was to evaluate the decolourization potential of textile dyes by a relatively newly identified bacteria species, Enterobacter sp. SXCR which was isolated from the petroleum polluted soil samples. The bacterial strain was identified by 16S rRNA gene sequence analysis. The effects of operational conditions like initial dye concentration, pH, and temperature were optimized to develop an economically feasible decolourization process. The isolate was able to decolourize sulphonated azo dye (Congo red) over a wide range (0.1-1 gl(-1)), pH 5-9, and temperature 22-40 degrees C in static condition. Anaerobic condition with minimal salt medium supplemented with 2 gl(-1) glucose, pH 7 and 34 degrees C were considered to be the optimum decolourizing condition. The bacterial isolate SXCR showed a strong ability to decolourize dye (0.2 gl(-1)) within 93 h. The biodegradation was monitored by UV-vis, fourier transform infra-red spectroscopy (FTIR) spectroscopy and high performance liquid chromatography (HPLC). Furthermore, the involvement of azoreductase in the decolourization process was identified in this strain. Cells of Enterobacter cloacae were immobilized by entrapment in calcium-alginate beads. Immobilized bacterial cells were able to reduced azo bonds enzymatically and used as a biocatalyst for decolourization of azo dye Congo red. Michaelis-Menten kinetics was used to describe the correlation between the decolourization rate and the dye concentration. PMID:24645479

  12. Further studies on the sources of Klebsiella aerogenes in hospital patients.

    PubMed Central

    Cooke, E. M.; Pool, R.; Brayson, J. C.; Edmondson, A. S.; Munro, M. E.; Shinebaum, R.

    1979-01-01

    We report an investigation into faecal carriage of Klebsiella aerogenes and the distribution of this organism in the environment of three wards. In all three wards faecal carriage rates were high (60-70%). The faecal carriage rate increased with antibiotic administration and with length of in-patient stay. K. aerogenes was widely distributed in the ward environment and was found on the hands of nursing staff. Clusters of isolations of K. aerogenes of the same serotype were demonstrated indicating either patient-to-patient transfer or a common source of infection. The results indicate that even under conditions in which there are no outbreaks of K. aerogenes infection, there is a large reservoir of this organism both in the bowel of patients and in the ward environment. PMID:390043

  13. The TyrR transcription factor regulates the divergent akr-ipdC operons of Enterobacter cloacae UW5.

    PubMed

    Coulson, Thomas J D; Patten, Cheryl L

    2015-01-01

    The TyrR transcription factor regulates genes involved in the uptake and biosynthesis of aromatic amino acids in Enterobacteriaceae. Genes may be positively or negatively regulated depending on the presence or absence of each aromatic amino acid, all three of which function as cofactors for TyrR. In this report we detail the transcriptional control of two divergently transcribed genes, akr and ipdC, by TyrR, elucidated by promoter fusion expression assays and electrophoretic mobility shift assays to assess protein-DNA interactions. Expression of both genes was shown to be controlled by TyrR via interactions with two TyrR boxes located within the akr-ipdC intergenic region. Expression of ipdC required TyrR bound to the proximal strong box, and is strongly induced by phenylalanine, and to a lesser extent by tryptophan and tyrosine. Down-regulation of akr was reliant on interactions with the weak box, and may also require a second, as yet unidentified protein for further repression. Tyrosine enhanced repression of akr. Electrophoretic mobility shift assays demonstrated that TyrR interacts with both the strong and weak boxes, and that binding of the weak box in vitro requires an intact adjacent strong box. While the strong box shows a high degree of conservation with the TyrR binding site consensus sequence, the weak box has atypical spacing of the two half sites comprising the palindromic arms. Site-directed mutagenesis demonstrated sequence-specific interaction between TyrR and the weak box. This is the first report of TyrR-controlled expression of two divergent protein-coding genes, transcribed from independent promoters. Moreover, the identification of a predicted aldo-keto reductase as a member of the TyrR regulon further extends the function of the TyrR regulon. PMID:25811953

  14. Methionine-to-Cysteine Recycling in Klebsiella aerogenes

    PubMed Central

    Seiflein, Thomas A.; Lawrence, Jeffrey G.

    2001-01-01

    In the enteric bacteria Escherichia coli and Salmonella enterica, sulfate is reduced to sulfide and assimilated into the amino acid cysteine; in turn, cysteine provides the sulfur atom for other sulfur-bearing molecules in the cell, including methionine. These organisms cannot use methionine as a sole source of sulfur. Here we report that this constraint is not shared by many other enteric bacteria, which can use either cysteine or methionine as the sole source of sulfur. The enteric bacterium Klebsiella aerogenes appears to use at least two pathways to allow the reduced sulfur of methionine to be recycled into cysteine. In addition, the ability to recycle methionine on solid media, where cys mutants cannot use methionine as a sulfur source, appears to be different from that in liquid media, where they can. One pathway likely uses a cystathionine intermediate to convert homocysteine to cysteine and is induced under conditions of sulfur starvation, which is likely sensed by low levels of the sulfate reduction intermediate adenosine-5′-phosphosulfate. The CysB regulatory proteins appear to control activation of this pathway. A second pathway may use a methanesulfonate intermediate to convert methionine-derived methanethiol to sulfite. While the transsulfurylation pathway may be directed to recovery of methionine, the methanethiol pathway likely represents a general salvage mechanism for recovery of alkane sulfide and alkane sulfonates. Therefore, the relatively distinct biosyntheses of cysteine and methionine in E. coli and Salmonella appear to be more intertwined in Klebsiella. PMID:11114934

  15. A hospital epidemic caused by gentamicin-resistant Klebsiella aerogenes.

    PubMed

    Curie, K; Speller, D C; Simpson, R A; Stephens, M; Cooke, D I

    1978-02-01

    In the 15 months, February 1976 to April 1977, more than 241 patients became colonized with a strain of Klebsiella aerogenes, capsular serotype K2, resistant to most antibiotics. Urinary tract infection was the most common clinical manifestation but bacteraemia and, occasionally, infections of other sites were encountered. The main reservoir of the epidemic klebsiella was the gut, urine and skin of colonized patients. Gut carriage among staff was very uncommon. The most susceptible patients were elderly males, with debilitating illnesses and urinary tract abnormalities, especially if they were catheterized or receiving antibiotics. Likely vehicles for spread were the hands of staff, and contaminated bedpans and urinals. Control measures were directed at these factors. At the end of April 1977 no new cases had occurred for 3 months in the ward in which the outbreak began, and which had been the main focus of infection, and only 5 patients in the affected hospitals were known to be colonized by the epidemic klebsiella. PMID:340580

  16. A hospital epidemic caused by gentamicin-resistant Klebsiella aerogenes.

    PubMed Central

    Curie, K.; Speller, D. C.; Simpson, R. A.; Stephens, M.; Cooke, D. I.

    1978-01-01

    In the 15 months, February 1976 to April 1977, more than 241 patients became colonized with a strain of Klebsiella aerogenes, capsular serotype K2, resistant to most antibiotics. Urinary tract infection was the most common clinical manifestation but bacteraemia and, occasionally, infections of other sites were encountered. The main reservoir of the epidemic klebsiella was the gut, urine and skin of colonized patients. Gut carriage among staff was very uncommon. The most susceptible patients were elderly males, with debilitating illnesses and urinary tract abnormalities, especially if they were catheterized or receiving antibiotics. Likely vehicles for spread were the hands of staff, and contaminated bedpans and urinals. Control measures were directed at these factors. At the end of April 1977 no new cases had occurred for 3 months in the ward in which the outbreak began, and which had been the main focus of infection, and only 5 patients in the affected hospitals were known to be colonized by the epidemic klebsiella. PMID:340580

  17. Inorganic phosphate accumulation and cadmium detoxification in Klebsiella aerogenes NCTC 418 growing in continuous culture

    SciTech Connect

    Aiking, H.; Stijnman, A.; van Garderen, C.; van Heerikhuizen, H.; van Riet, J.

    1984-02-01

    Klebsiella aerogenes NCTC-418, growing in the presence of cadmium under glucose-, sulfate-, or phosphate-limited conditions in continuous culture, exhibits two different cadmium detoxifying mechanisms. In addition to sulfide formation, increased accumulation of P/sub i/ is demonstrated as a novel mechanism. Intracellular cadmium is always quantitatively counterbalanced by a concerted increase in both inorganic sulfide and P/sub i/ contents of the cells. This led to the conclusion that production of sulfide and accumulation of P/sub i/ are detoxification mechanisms present in K. aerogenes but that their relative importance is crucially dependent on the strain and the growth conditions employed.

  18. Purification and characterization of a GH43 β-xylosidase from Enterobacter sp. identified and cloned from forest soil bacteria.

    PubMed

    Campos, Eleonora; Negro Alvarez, María José; Sabarís di Lorenzo, Gonzalo; Gonzalez, Sergio; Rorig, Marcela; Talia, Paola; Grasso, Daniel H; Sáez, Felicia; Manzanares Secades, Paloma; Ballesteros Perdices, Mercedes; Cataldi, Angel A

    2014-01-01

    The use of lignocellulosic biomass for second generation biofuels requires optimization of enzymatic breakdown of plant cell walls. In this work, cellulolytic bacteria were isolated from a native and two cultivated forest soil samples. Amplification of glycosyl hydrolases was attempted by using a low stringency-degenerate primer PCR strategy, using total soil DNA and bulk DNA pooled from positive colonies as template. A set of primers was designed based on Acidothermus cellulolyticus genome, by search of conserved domains of glycosyl hydrolases (GH) families of interest. Using this approach, a fragment containing an open reading frame (ORF) with 98% identity to a putative GH43 beta-xylosidase coding gene from Enterobacter cloacae was amplified and cloned. The full protein was expressed in Escherichia coli as N-terminal or C-terminal His-tagged fusions and purified under native conditions. Only N-terminal fusion protein, His-Xyl43, presented beta-xylosidase activity. On pNPX, optimal activity was achieved at pH 6 and 40 °C and Km and Kcat values were 2.92 mM and 1.32 seg(-1), respectively. Activity was also demonstrated on xylobiose (X2), with Km 17.8 mM and Kcat 380 s(-1). These results demonstrated that Xyl43 is a functional beta-xylosidase and it is the first evidence of this activity for Enterobacter sp. PMID:23838121

  19. Early urologic considerations in patients with persistent cloaca.

    PubMed

    VanderBrink, Brian A; Reddy, Pramod P

    2016-04-01

    Cloacal malformations represent one of the most complex conditions among anorectal malformations. Urologic conditions occur with an increased frequency in cloaca patients compared to patients with other types of ARM. The morbidity of the upper and lower urinary tract dysfunction/malformations at times can be severe; manifested by urinary tract infection, lower urinary tract symptoms, urinary incontinence, chronic kidney disease, and even end stage renal disease. Long-term follow-up of patients with cloaca has described significant chronic kidney disease and end-stage renal disease. Whether this rate of chronic kidney disease is a function of intrinsic renal dysplasia or acquired renal injury from neurogenic bladder is currently unknown. However, it is well known that severe lower urinary tract dysfunction, no matter the etiology, poses significant risk to the upper tracts when untreated. Neonatal assessment of the urinary tract accompanied by early identification of abnormal structure and function is therefore fundamental to minimize the impact of any urologic condition on the child's overall health. Adequate management of any associated bladder dysfunction is essential to preserving renal function, minimizing risk of urinary tract infection, and potentially avoiding need for future reconstructive surgery. This article summarizes our institution's approach to the ongoing early urologic management in patients with cloaca. PMID:26969231

  20. The Function of UreB in Klebsiella aerogenes Urease†

    PubMed Central

    Carter, Eric L.; Boer, Jodi L.; Farrugia, Mark A.; Flugga, Nicholas; Towns, Christopher L.; Hausinger, Robert P.

    2011-01-01

    Urease from Klebsiella aerogenes is composed of three subunits (UreA, UreB, and UreC) which assemble into a (UreABC)3 quaternary structure. UreC harbors the dinuclear nickel active site, whereas the functions of UreA and UreB remain unknown. UreD and UreF accessory proteins previously were suggested to reposition UreB and increase exposure of the nascent urease active site, thus facilitating metallocenter assembly. In this study, cells were engineered to separately produce (UreAC)3 or UreB, and the purified proteins were characterized. Monomeric UreB spontaneously binds to the trimeric heterodimer of UreA plus UreC to form (UreABC*)3 apoprotein, as shown by gel filtration chromatography, integration of electrophoretic gel band intensities, and mass spectrometry. Similar to authentic urease apoprotein, active enzyme is produced by incubation of (UreABC*)3 with Ni2+ and bicarbonate. Conversely, UreBΔ1-19, lacking the 19 residue potential hinge and tether to UreC, does not form a complex with (UreAC)3 and yields negligible levels of active enzyme when incubated under activation conditions with (UreAC)3. Comparison of activities and nickel contents for (UreAC)3, (UreABC*)3, and (UreABC)3 samples treated with Ni2+ and bicarbonate and then desalted indicates that UreB facilitates efficient incorporation of the metal into the active site and protects the bound metal from chelation. Amylose resin pull-down studies reveal that MBP-UreD (a fusion of maltose binding protein with UreD) forms complexes with (UreABC)3, (UreAC)3, and UreB in vivo, but not in vitro. By contrast, MBP-UreD does not form an in vivo complex with UreBΔ1-19. The soluble MBP-UreD:UreF:UreG complex binds in vitro to (UreABC)3, but not to (UreAC)3 or UreB. Together these data demonstrate that UreB facilitates the interaction of urease with accessory proteins during metallocenter assembly, with the N-terminal hinge and tether region being specifically required for this process. In addition to its role in

  1. Enterobacter morus sp. nov., a novel Enterobacter species associated with bacterial wilt on mulberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A mulberry pathogenetic bacterial strain R18-2T isolated from the diseased mulberry root was analyzed by a polyphasic taxonomic study. Comparative 16S rRNA gene sequence analysis combined with rpoB gene sequence analysis allocated the strain R18-2T to the genus Enterobacter. The strain was Gram nega...

  2. Enhanced Aerogen-π Interaction by a Cation-π Force.

    PubMed

    Miao, Junjian; Song, Bo; Gao, Yi

    2016-02-18

    The interaction between a noble gas atom and an aromatic π-electron system, which mainly originates from the London dispersion force, is very weak and has not attracted enough attention yet. Herein, we reported a type of notably enhanced aerogen-π interaction between cation-π systems and noble gas atoms. The binding strength of a divalent cation-π system with a xenon atom is comparable to a moderate hydrogen bond (up to ca. 7 kcal mol(-1)), whereas krypton and argon atoms produce slightly weaker interactions. Energy-decomposition analysis reveals that the induction interaction is responsible for the stabilization of divalent cation-π⋅Xe species besides the dispersion interaction. Our results might be helpful to increase the understanding of some unsolved mysteries of aerogens. PMID:26699400

  3. [Evaluation of aerogenic occupational health risk for workers engaged into periclase-carbon refractories production].

    PubMed

    Drugova, O G; Roslyĭ, O F

    2014-01-01

    The work is aimed to evaluate aerogenic occupational health risk for workers engaged into preparation and formation of technologic mass in periclase-carbon refractories production, using organic binding agent according to criteria R 2.2.2006-05 and R 2.2.1716-03. Occupational dust is a complicated chemical mixture containing manganum oxide, phenol, formaldehyde, aerosols containing silicon, benzpyrene (if "Carbores" binding agent used). Hygienic evaluation revealed occupational health risk due to occupational dust at workplaces of runners operator, press operator, batching feeder, crane operator. Aerogenic occupational risk at workplace of grinder operator is assessed as negligibly small (tolerable). Experimental and epidemiologic studies prove probable (proof category 1B) occupational risk of respiratory disease at the studied production. PMID:25282807

  4. Glutamine synthetase of Klebsiella aerogenes: properties of glnD mutants lacking uridylyltransferase.

    PubMed Central

    Foor, F; Cedergren, R J; Streicher, S L; Rhee, S G; Magasanik, B

    1978-01-01

    The glnD mutation of Klebsiella aerogenes is cotransducible by phage P1 with pan (requirement for pantothenate) and leads to a loss of uridylytransferase and uridylyl-removing enzyme, components of the glutamine synthetase adenylylation system. This defect results in an inability to deadenylylate glutamine synthetase rapidly and in a requirement for glutamine for normal growth. Suppression of the glnD mutation are located at the glutamine synthetase structural gene glnA. PMID:26659

  5. Biohydrogen production by co-fermentation of crude glycerol and apple pomace hydrolysate using co-culture of Enterobacter aerogenes and Clostridium butyricum.

    PubMed

    Pachapur, Vinayak Laxman; Sarma, Saurabh Jyoti; Brar, Satinder Kaur; Le Bihan, Yann; Buelna, Gerardo; Verma, Mausam

    2015-10-01

    Co-substrate utilization of various wastes with complementary characteristics can provide a complete medium for higher hydrogen production. This study evaluated potential of apple pomace hydrolysate (APH) co-fermented with crude glycerol (CG) for increased H2 production and decreased by-products formation. The central composite design (CCD) along with response surface methodology (RSM) was used as tool for optimization and 15 g/L of CG, 5 g/L of APH and 15% (v/v) inoculum were found to be optimum to produce as high as 26.07 ± 1.57 mmol H2/L of medium. The p-value of 0.0017 indicated that APH at lower concentration had a significant effect on H2 production. By using CG as sole carbon source, reductive pathway of glycerol metabolism was favored with 19.46 mmol H2/L. However, with APH, oxidative pathway was favored with higher H2 production (26.07 ± 1.57 mmol/L) and decrease in reduced by-products (1,3-propanediol and ethanol) formation. APH inclusion enhanced H2 production, and decreased substrate inhibition. PMID:26142996

  6. Phage-mediated Shiga toxin (Stx) horizontal gene transfer and expression in non-Shiga toxigenic Enterobacter and Escherichia coli strains.

    PubMed

    Khalil, Rowaida K S; Skinner, Craig; Patfield, Stephanie; He, Xiaohua

    2016-07-01

    Enterobacter cloacae M12X01451 strain recently identified from a clinical specimen produces a new Stx1 subtype (Stx1e) that was not neutralized by existing anti-Stx1 monoclonal antibodies. Acquisition of stx by Ent. cloacae is rare and origin/stability of stx1e in M12X01451 is not known. In this study, we confirmed the ability of Stx1a- and Stx1e-converting phages from an Escherichia coli O157:H7 strain RM8530 and M12X01451 respectively to infect several E. coli and Ent. cloacae strains. stx1e was detected in 97.5% and 72.5% of progenies of strains lysogenized by stx1e phage after 10 (T10) and 20 (T20) subcultures, versus 65% and 17.5% for stx1a gene. Infection of M12X01451 and RM8530 with each other's phages generated double lysogens containing both phages. stx1a was lost after T10, whereas the stx1e was maintained even after T20 in M12X01451 lysogens. In RM8530 lysogens, the acquired stx1e was retained with no mutations, but 20% of stx1a was lost after T20 ELISA and western blot analyses demonstrated that Stx1e was produced in all strains lysogenized by stx1e phage; however, Stx1a was not detected in any lysogenized strain. The study results highlight the potential risks of emerging Stx-producing strains via bacteriophages either in the human gastrointestinal tract or in food production environments, which are matters of great concern and may have serious impacts on human health. PMID:27109772

  7. Purification and characterization of the nickel-containing multicomponent urease from Klebsiella aerogenes.

    PubMed

    Todd, M J; Hausinger, R P

    1987-05-01

    Klebsiella aerogenes urease was purified 1,070-fold with a 25% yield by a simple procedure involving DEAE-Sepharose, phenyl-Sepharose, Mono Q, and Superose 6 chromatographies. The enzyme preparation was comprised of three polypeptides with estimated Mr = 72,000, 11,000, and 9,000 in a alpha 2 beta 4 gamma 4 quaternary structure. The three components remained associated during native gel electrophoresis, Mono Q chromatography, and Superose 6 chromatography despite the presence of thiols, glycols, detergents, and varied buffer conditions. The apparent compositional complexity of K. aerogenes urease contrasts with the simple well-characterized homohexameric structure for jack bean urease (Dixon, N. E., Hinds, J. A., Fihelly, A. K., Gazzola, C., Winzor, D. J., Blakeley, R. L., and Zerner, B. (1980) Can. J. Biochem. 58, 1323-1334); however, heteromeric subunit compositions were also observed for the enzymes from Proteus mirabilis, Sporosarcina ureae, and Selemonomas ruminantium. K. aerogenes urease exhibited a Km for urea of 2.8 +/- 0.6 mM and a Vmax of 2,800 +/- 200 mumol of urea min-1 mg-1 at 37 degrees C in 25 mM N-2-hydroxyethylpiperazineN'-2-ethanesulfonic acid, 5.0 mM EDTA buffer, pH 7.75. The enzyme activity was stable in 1% sodium dodecyl sulfate, 5% Triton X-100, 1 M KCl, and over a pH range from 5 to 10.5, with maximum activity observed at pH 7.75. Two active site groups were defined by their pKa values of 6.55 and 8.85. The amino acid composition of K. aerogenes urease more closely resembled that for the enzyme from Brevibacter ammoniagenes (Nakano, H., Takenishi, S., and Watanabe, Y. (1984) Agric. Biol. Chem. 48, 1495-1502) than those for plant ureases. Atomic absorption analysis was used to establish the presence of 2.1 +/- 0.3 mol of nickel per mol of 72,000-dalton subunit in K. aerogenes urease. PMID:3553184

  8. Escherichia fergusonii and Enterobacter taylorae, two new species of Enterobacteriaceae isolated from clinical specimens.

    PubMed Central

    Farmer, J J; Fanning, G R; Davis, B R; O'Hara, C M; Riddle, C; Hickman-Brenner, F W; Asbury, M A; Lowery, V A; Brenner, D J

    1985-01-01

    Escherichia fergusonii (formerly known as Enteric Group 10) and Enterobacter taylorae (formerly known as Enteric Group 19) are proposed as new species in the family Enterobacteriaceae. By DNA hybridization (32P, 60 degrees C, hydroxyapatite), strains of E. fergusonii were 90 to 97% related to the type strain (holotype) ATCC 35469. They were most closely related to Escherichia coli and more distantly related to species in other genera. E. fergusonii strains are positive for indole production, methyl red, lysine decarboxylase, ornithine decarboxylase, and motility. They ferment D-glucose with gas production and also ferment adonitol, L-arabinose, L-rhamnose, maltose, D-xylose, trehalose, cellobiose, and D-arabitol. They are negative for Voges-Proskauer, citrate utilization (17% positive), urea hydrolysis, phenylalanine deamination, arginine dihydrolase, growth in KCN, and fermentation of lactose, sucrose, myo-inositol, D-sorbitol, raffinose, and alpha-methyl-D-glucoside. By DNA hybridization (32P, 60 degrees C, hydroxyapatite), strains of E. taylorae were 84 to 95% related to the type strain (holotype) ATCC 35317. Their nearest relative was E. cloacae, to which they were 61% related. Other named species were more distantly related. Strains of E. taylorae are positive for Voges-Proskauer, citrate utilization, arginine dihydrolase, ornithine decarboxylase, motility, growth in KCN medium, and malonate utilization. They ferment D-glucose with gas production and also ferment D-mannitol, L-arabinose, L-rhamnose, maltose, D-xylose, trehalose, and cellobiose. They are negative for indole production, methyl red, H2S production on triple sugar-iron agar, urea hydrolysis, phenylalanine deamination, lysine decarboxylase, gelatin hydrolysis, and fermentation of adonitol, i-inositol, D-sorbitol, and raffinose. Both new species occur in human clinical specimens. Two strains of E. fergusonii were isolated from blood. Five stains of E. taylorae were isolated from blood, and one was

  9. Cronobacter (Enterobacter sakazakii): an opportunistic foodborne pathogen.

    PubMed

    Healy, Brendan; Cooney, Shane; O'Brien, Stephen; Iversen, Carol; Whyte, Paul; Nally, Jarlath; Callanan, John J; Fanning, Séamus

    2010-04-01

    Cronobacter spp. (Enterobacter sakazakii) are a recently described genus that is comprised of six genomospecies. The classification of these organisms was revised based on a detailed polyphasic taxonomic study. Cronobacter spp. are regarded as ubiquitous organisms having been isolated from a wide variety of foods. These bacteria are opportunistic pathogens and are linked with life-threatening infections in neonates. Clinical symptoms of Cronobacter infection include necrotizing enterocolitis, bacteremia, and meningitis, with case fatality rates of 50-80% being reported. Contaminated powdered infant formula has been epidemiologically linked with infections. Recently, infections among immunocompromised adults, mainly the elderly, have also been reported. A high tolerance to osmotic stress and elevated temperatures contribute to the survival of Cronobacter spp. in dried foods such as powdered infant formula. Controlling the organism in the production environment, thereby reducing dissemination, necessitates the provision of suitable diagnostic tools. Studies demonstrated that a high degree of variability exists amongst the phenotypic-based methods used to identify Cronobacter spp. However, advances in molecular detection and subtyping techniques have significantly improved the identification and characterization of Cronobacter spp. The dose required to induce infection has yet to be determined. In vitro virulence studies have shown that Cronobacter spp. may survive in macrophage cells and efficiently attach to and invade epithelial cell lines. The production of exopolysaccharide may contribute to the formation of biofilm and active efflux pumps promote resistance to antimicrobial agents such as bile salts and disinfectants. A holistic approach combining techniques such as comparative genome analysis, proteomics, and in vivo challenges could help unravel the complex interactions between this pathogen and its host. These data would help identify those properties in

  10. Effect of Several Clay Minerals and Humic Acid on the Survival of Klebsiella aerogenes Exposed to Ultraviolet Irradiation1

    PubMed Central

    Bitton, Gabriel; Henis, Y.; Lahav, N.

    1972-01-01

    The effect of various clay minerals and humic acid on the survival of Klebsiella aerogenes exposed to ultraviolet (UV) irradiation was investigated. A protective effect was observed and found to depend on the specific light absorption and light scattering properties of the clay minerals and the humic acid used. The higher the specific absorption, the better was the survival of K. aerogenes after UV irradiation. Bacterial survival was lower in clays saturated with divalent cations (Ca, Zn) than in those homoionic to monovalent cations (K). PMID:5031559

  11. Continuous mode of carbon dioxide sequestration by C. sorokiniana and subsequent use of its biomass for hydrogen production by E. cloacae IIT-BT 08.

    PubMed

    Kumar, Kanhaiya; Roy, Shantonu; Das, Debabrata

    2013-10-01

    The present study investigated to find out the suitability of the CO2 sequestered algal biomass of Chlorella sorokiniana as substrate for the hydrogen production by Enterobacter cloacae IIT-BT 08. The maximum biomass productivity in continuous mode of operation in autotrophic condition was enhanced from 0.05 g L(-1) h(-1) in air to 0.11 g L(-1) h(-1) in 5% air-CO2 (v/v) gas mixture at an optimum dilution rate of 0.05 h(-1). Decrease in steady state biomass and productivity was less sensitive at higher dilution and found fitting with the model proposed by Eppley and Dyer (1965). Pretreated algal biomass of 10 g L(-1) with 2% (v/v) HCl-heat was found most suitable for hydrogen production yielding 9±2 mol H2 (kg COD reduced)(-1) and was found fitting with modified Gompertz equation. Further, hydrogen energy recovery in dark fermentation was significantly enhanced compared to earlier report of hydrogen production by biophotolysis of algae. PMID:23453984

  12. Genotypic and Phenotypic Detection of AmpC β-lactamases in Enterobacter spp. Isolated from a Teaching Hospital in Malaysia

    PubMed Central

    Mohd Khari, Fatin Izzati; Karunakaran, Rina; Rosli, Roshalina; Tee Tay, Sun

    2016-01-01

    Objectives The objective of this study was to determine the occurrence of chromosomal and plasmid-mediated β-lactamases (AmpC) genes in a collection of Malaysian isolates of Enterobacter species. Several phenotypic tests for detection of AmpC production of Enterobacter spp. were evaluated and the agreements between tests were determined. Methods Antimicrobial susceptibility profiles for 117 Enterobacter clinical isolates obtained from the Medical Microbiology Diagnostic Laboratory, University Malaya Medical Centre, Malaysia, from November 2012—February 2014 were determined in accordance to CLSI guidelines. AmpC genes were detected using a multiplex PCR assay targeting the MIR/ACT gene (closely related to chromosomal EBC family gene) and other plasmid-mediated genes, including DHA, MOX, CMY, ACC, and FOX. The AmpC β-lactamase production of the isolates was assessed using cefoxitin disk screening test, D69C AmpC detection set, cefoxitin-cloxacillin double disk synergy test (CC-DDS) and AmpC induction test. Results Among the Enterobacter isolates in this study, 39.3% were resistant to cefotaxime and ceftriaxone and 23.9% were resistant to ceftazidime. Ten (8.5%) of the isolates were resistant to cefepime, and one isolate was resistant to meropenem. Chromosomal EBC family gene was amplified from 36 (47.4%) E. cloacae and three (25%) E. asburiae. A novel blaDHA type plasmid-mediated AmpC gene was identified for the first time from an E. cloacae isolate. AmpC β-lactamase production was detected in 99 (89.2%) of 111 potential AmpC β-lactamase producers (positive in cefoxitin disk screening) using D69C AmpC detection set. The detection rates were lower with CC-DDS (80.2%) and AmpC induction tests (50.5%). There was low agreement between the D69C AmpC detection set and the other two phenotypic tests. Of the 40 isolates with AmpC genes detected in this study, 87.5%, 77.5% and 50.0% of these isolates were positive by the D69C AmpC detection set, CC-DDS and Amp

  13. Congenital cloaca: Long-term follow-up results with emphasis on outcomes beyond childhood.

    PubMed

    Rintala, Risto J

    2016-04-01

    Persistent cloaca remains a challenge for pediatric surgeons and urologists. Reconstructive surgery of cloacal malformations aims to repair the anorectum, urinary tract, and genital organs, and achieve fecal and urinary continence as well as functional genital tract capable for sexual activity and pregnancy. Unfortunately, even in most experienced hands these goals are not always accomplished. The endpoint of the functional development of bowel, urinary, and genital functions is the completion of patient's growth and sexual maturity. It is unlikely that there will be any significant functional improvement beyond these time points. About half of the patients with cloaca attain fecal and urinary continence after their growth period. The remaining half stay clean or dry by adjunctive measures such as bowel management by enemas or ACE channel, and continent urinary diversion or intermittent catheterization. Problems related to genital organs such as obstructed menstruations, amenorrhea, and introitus stenosis are common and often require secondary surgery. Encouragingly, most adolescent and adult patients are capable of sexual life despite often complex vaginal primary and secondary reconstructions. Also, cloacal malformation does not preclude pregnancies, although they still are quite rare. Pregnant patients with cloaca require special care and follow-up to guarantee uncomplicated pregnancy and preservation of anorectal and urinary functions. Cesarean section is recommended for cloaca patients. The self-reported quality of life of cloaca patients appears to be comparable to that of female patients with less complex anorectal malformations. PMID:26969236

  14. Regulation of nitrogen metabolism in Escherichia coli and Klebsiella aerogenes: studies with the continuous-culture technique.

    PubMed Central

    Senior, P J

    1975-01-01

    Ammonia-nitrogen-limited continuous cultures of Escherichia coli and Klebsiella aerogenes contain induced levels of glutamine synthetase that is deadenylyated (i.e., fully active). In the presence of excess ammonia or glutamate in glucose-limited cultures of E. coli, glutamine synthetase is repressed and adenylylated (inactive). The average state of adenylylation (n) is a linear function of the specific growth rate. At low specific growth rates, glutamine synthetase is adenylylated; as the specific growth rate increases, n decreases, approaching 0 to 2 at rapid growth rates. The average state of adenylylation correlates well with the intracellular concentrations and ratios of alpha-ketoglutarate and glutamine, which are key effectors in the adenylylation-deadenylylation systems. E. coli and K. aerogenes differ markedly in their growth yields, growth rates, and enzymatic composition during nitrogen limitation. The data suggest that, unlike K. aerogenes, E. coli W uses glutamate dehydrogenase to incorporate ammonia during nitrogen limitation. In E. coli, glutamate dehydrogenase is progressively induced during nitrogen limitation when mu (growth rate) approaches mumax. In contrast, in K. aerogenes glutamate dehydrogenase is repressed during nitrogen limitation, whereas glutamate synthase, an alternative supplier of glutamate to the cell, is induced. Data are presented that support the regulatory schemes proposed for the control of glutamine synthetase activity by induction-repression phenomena and adenylylation-deadenylylation reaction. We propose that the intracellular ratio of alpha-ketoglutarate to glutamine may be the most important physiological parameter in determining the activity of glutamine synthetase. PMID:238954

  15. Complete Genome Sequence of a Clinical Isolate of Enterobacter asburiae

    PubMed Central

    Liu, Feng; Yang, Jian; Xiao, Yan; Li, Li; Jin, Qi

    2016-01-01

    We report here the complete genome sequence of Enterobacter asburiae strain ENIPBJ-CG1, isolated from a bone marrow transplant patient. The size of the genome sequence is approximately 4.65 Mb, with a G+C content of 55.76%, and it is predicted to contain 4,790 protein-coding genes. PMID:27284137

  16. New monoclonal antibodies against a novel subtype of Shiga toxin 1 produced by Enterobacter cloacae and their use in analysis of human serum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin (Stx) is a major virulence factor for several bacterial pathogens that cause potentially fatal illness, including Escherichia coli and Shigella spp. The continual emergence of new subtypes of Stxs presents challenges in clinical diagnosis of infections caused by Shiga toxin-producing org...

  17. [Cloning and function identification of gene 'admA' and up-stream regulatory sequence related to antagonistic activity of Enterobacter cloacae B8].

    PubMed

    Zhu, Jun-Li; Li, De-Bao; Yu, Xu-Ping

    2012-04-01

    To reveal the antagonistic mechanism of B8 strain to Xanthomonas oryzae pv. oryzae, transposon tagging method and chromosome walking were deployed to clone antagonistic related fragments around Tn5 insertion site in the mutant strain B8B. The function of up-stream regulatory sequence of gene 'admA' involved in the antagonistic activity was further identified by gene knocking out technique. An antagonistic related left fragment of Tn5 insertion site, 2 608 bp in length, was obtained by tagging with Kan resistance gene of Tn5. A 2 354 bp right fragment of Tn5 insertion site was amplified with 2 rounds of chromosome walking. The length of the B contig around the Tn5 insertion site was 4 611 bp, containing 7 open reading frames (ORFs). Bioinformatic analysis revealed that these ORFs corresponded to the partial coding regions of glyceraldehyde-3-phosphate dehydrogenase, two LysR family transcriptional regulators, hypothetical protein VSWAT3-20465 of Vibrionales and admA, admB, and partial sequence of admC gene of Pantoea agglomerans biosynthetic gene cluster, respectively. Tn5 was inserted in the up-stream of 200 bp or 894 bp of the sequence corresponding to anrP ORF or admA gene on B8B, respectively. The B-1 and B-2 mutants that lost antagonistic activity were selected by homeologuous recombination technology in association with knocking out plasmid pMB-BG. These results suggested that the transcription and expression of anrP gene might be disrupted as a result of the knocking out of up-stream regulatory sequence by Tn5 in B8B strain, further causing biosythesis regulation of the antagonistic related gene cluster. Thus, the antagonistic related genes in B8 strain is a gene family similar as andrimid biosynthetic gene cluster, and the upstream regulatory region appears to be critical for the antibiotics biosynthesis. PMID:22522167

  18. Predominance of KPC-3 in a Survey for Carbapenemase-Producing Enterobacteriaceae in Portugal

    PubMed Central

    Manageiro, Vera; Ferreira, Eugénia; Almeida, Joana; Barbosa, Stephanie; Simões, Constança; Bonomo, Robert A.

    2015-01-01

    Among the 2,105 Enterobacteriaceae tested in a survey done in Portugal, 165 were nonsusceptible to carbapenems, from which 35 (26 Klebsiella pneumoniae, 3 Escherichia coli, 2 Enterobacter aerogenes, and 3 Enterobacter cloacae isolates and 1 Klebsiella oxytoca isolate) were confirmed to be carbapenemase producers by the presence of 30 Tn4401d-blaKPC-3, 4 intI3-blaGES-5, and one intI1-blaVIM-2 gene, alone or in combination with other bla genes. The dissemination of blaKPC-3 gene carried by an IncF plasmid suggests lateral gene transfer as a major mechanism of dissemination. PMID:25779587

  19. Glutamate dehydrogenase: genetic mapping and isolation of regulatory mutants of Klebsiella aerogenes.

    PubMed Central

    Bender, R A; Macaluso, A; Magasanik, B

    1976-01-01

    The gene for glutamate dehydrogenase (gdhD) has been mapped in Klebsiella aerogenes by P1 transduction. It is linked to pyrF and trp with the order pyrF-trp-gdh. Complementation analysis using F' episomes from Escherichia coli suggests an analogous location in E. coli. Two mutants able to produce glutamate dehydrogenase in the presence of high levels of glutamine synthetase have been isolated. One, tightly linked to gdhD, shows normal repression control by glutamine synthetase but produces four times as much glutamate dehydrogenase activity as does the wild type under all conditions tested. The other revertant is not linked to gdhD or glnA. PMID:6429

  20. Biodegradation of dichlorodiphenyltrichloroethane: intermediates in dichlorodiphenylacetic acid metabolism by aerobacter aerogenes

    USGS Publications Warehouse

    Wedemeyer, Gary

    1967-01-01

    The final product of dichlorodiphenyltrichloroethane (DDT) degradation by vertebrates is commonly considered to be dichlorodiphenylacetic acid, DDA. Recently, certain organisms have been found to degrade further DDA to dichlorobenzophenone (DBP), but the possibility that such degradation was due to microbial action could not be excluded. Significantly, dichlorobenzhydrol (DBH), dichlorophenylmethane (DPM), and dichlorodiphenylethylene (DDE) have been tentatively identified in rats fed DDA. Since DDA as well as DDT is degraded by the ubiquitous microorganism Aerobacter aerogenes, it seemed reasonable that the intestinal microflora might be involved in DBP formation, DPM and DBH being intermediates in its pathway from DDA. Since DDA is a (3,y-unsaturated acid, ketone formation via an alkene and an alcohol would be expected.

  1. Antibiotic susceptibilities of Serratia marcescens and Enterobacter liquefaciens.

    PubMed

    Greenup, P; Blazevic, D J

    1971-09-01

    Production of 5'-nucleotides by Serratia marcescens and Enterobacter liquefaciens correlates with deoxyribonuclease production, indicating the close relationship between these two organisms. To determine further relationships, susceptibilities of 279 strains of the tribe Klebsielleae were determined by the high-potency disc method, agar-dilution method, or both, by using 14 antibiotics. Ninety-seven per cent of S. marcescens (201 of 207 strains) and 100% of E. liquefaciens (17 strains) had minimum inhibitory concentration (MIC) of 100 mug/ml or greater with colistin and polymyxin B. With these two antibiotics, 93% of other Enterobacter species (28 strains) had MIC values of less than 1.6 mug/ml, and 100% of Klebsiella (27 strains) had MIC values less than 1.6 mug/ml. Consistent patterns were not noted with the other antibiotics tested, but the results with colistin and polymyxin B provide additional evidence of the close relationship of S. marcescens and E. liquefaciens. PMID:4330312

  2. Exploring "aerogen-hydride" interactions between ZOF2 (Z = Kr, Xe) and metal hydrides: An ab initio study

    NASA Astrophysics Data System (ADS)

    Esrafili, Mehdi D.; Mohammadian-Sabet, Fariba

    2016-06-01

    In this work, a new σ-hole interaction formed between ZOF2 (Z = Kr and Xe) as the Lewis acid and a series of metal-hydrides HMX (M = Be, Mg, Zn and X = H, F, CN, CH3) is reported. The nature of this interaction, called "aerogen-hydride" interaction, is unveiled by molecular electrostatic potential, non-covalent interaction, quantum theory of atoms in molecules and natural bond orbital analyses. Our results indicate that the aerogen-hydride interactions are quite strong and can be comparable in strength to other σ-hole bonds. An important charge-transfer interaction is also associated with the formation of OF2Z⋯HMX complexes.

  3. Random mutagenesis of pullulanase from Klebsiella aerogenes for studies of the structure and function of the enzyme.

    PubMed

    Yamashita, M; Kinoshita, T; Ihara, M; Mikawa, T; Murooka, Y

    1994-12-01

    To study the structure and function of pullulanase from Klebsiella aerogenes, a method involving random mutagenesis of the entire gene for pullulanase was used. Out of 50,000 clones screened at high temperature, seven genes for mutant proteins were identified by DNA sequencing. The amino acid substitutions in the seven mutant proteins were clustered on the NH2-terminal side of the four conserved regions found in alpha-amylases. These mutant pullulanases were classified into two types: those whose catalytic activity was altered and those whose thermal stability was increased. The results presented here and in previous reports suggest that pullulanase from K. aerogenes has similar active sites to those of alpha-amylases with the four conserved regions, as well as another substrate-binding site closer to the NH2-terminus. The plate assay method used for isolation of thermostable variants may be applicable to the generation of useful variants of other enzymes. PMID:7706211

  4. [Aerogenic microflora in animal husbandry and poultry breeding areas, criteria of its harmful effect and hygienic regulation].

    PubMed

    Erman, M I; Eglite, M E; Olefir, A I; Kalinina, L N

    1989-01-01

    In consequence of the analysis of workers' health status and microbic contamination of the working zone of animal and poultry husbandry production area the study established direct dependence of microorganism sensitization rate, incidence of infectious and allergic skin and respiratory diseases on microbic aerosol concentration. Feasibility of aerogenic microflora standardization was substantiated proceeding from the comparison of hygienic and clinical findings; MAC for microbic aerosol was set up for the working zone. PMID:2744566

  5. Effect of Growth Rate on Histidine Catabolism and Histidase Synthesis in Aerobacter aerogenes1

    PubMed Central

    Jensen, Donald E.; Neidhardt, Frederick C.

    1969-01-01

    A study was made of how the catabolism of a carbon and energy source is affected by the biosynthetic demands of growing bacterial cells. Cultures of Aerobacter aerogenes in l-histidine medium were grown in a chemostat at rates determined by the supply of either sulfate or a required amino acid, l-arginine. It was discovered that the rate at which these cells grow under a biosynthetic restriction determines both the rate and the pattern of histidine degradation. (i) Histidine catabolism is partially coupled to the growth rate. This coupling is achieved by catabolite repression of histidase (histidine ammonia lyase; EC 4.3.1.3.), and also by a slightly decreased in vivo function of this enzyme at low growth rates. (ii) The looseness of the coupling results in a direct relationship between growth rate and growth yield, and possibly is correlated with an altered pattern of carbon flow from histidine. (iii) Sudden decreases in growth rate cause total repression of histidase synthesis for substantial periods of time. (iv) Sudden release of biosynthetic restriction leads rapidly to an increase in the functioning of the cells' complement of histidase, an increase in the rate of synthesis of this enzyme, and an increase in the growth yield from histidine. PMID:5781570

  6. Biodegradation of ichlorodiphenyltrichloroe-thane: Intermediates in dichlorodiphenylacetic acid metabolism by Aerobacter aerogenes

    USGS Publications Warehouse

    1967-01-01

    The final product of dichlorodiphenyltrichloroethane (DDT) degradation by vertebrates is commonly considered to be dichlorodiphenylacetic acid, DDA (J. E. Peterson and W. H. Robison, Toxicol. Appl. Pharmacol. 6:321, 1964). Recently, certain organisms (A. S. Perry, S. Miller, and A. J. Buckner. J. Agr. Food Chem. 11:457, 1963; J. D. Pinto, M. N. Comien, and M. S. Dunn. J. Biol. Chem. 240:2148, 1965) have been found to degrade further DDA to dichlorobenzophenone (DBP), but the possibility that such degradation was due to microbial action could not be excluded. Significantly, dichlorobenzhydrol (DBH), dichlorophenylmethane (DPM), and dichlorodiphenylethylene (DDE) have been tentatively identified in rats fed DDA (Pinto et al., J. Biol. Chem. 240:2148, 1965). Since DDA as well as DDT is degraded by the ubiquitous microorganism Aerobacter aerogenes (G. Wedemeyer, Appl. Microbiol. 15:569, 1967; J. L. Mendel, and M. S. Walton, Science 151:1527, 1966), it seemed reasonable that the intestinal microflora might be involved in DBP formation, DPM and DBH being intermediates in its pathway from DDA. Since DDA is a (3,y-unsaturated acid, ketone formation via an alkene and an alcohol would be expected (S. G. Waley, Mechanisms of Organic and Enzymatic Reactions, Oxford University Press, London, England 1962).

  7. Growth and heavy metal removal by Klebsiella aerogenes at different pH and temperature

    SciTech Connect

    Al-Shahwani, M.F.; Jazrawi, S.F.; Al-Rawi, E.H.; Ayar, N.S.

    1984-01-01

    A strain of Klebsiella aerogenes isolated from Rustamiyah Station for treatment of wastewater was examined for its ability to grow in a media supplemented with maximum tolerance concentrations of Pb/sup + +/, Zn/sup + +/, Ni/sup + +/, and Cd/sup + +/, separately, at different temperatures and initial pH. The results indicated that at 28/sup 0/C during the first 24 hr, Pb/sup + +/ and Ni/sup + +/ had no effect on the growth of the bacteria, while the presence of Zn/sup + +/ and Cd/sup + +/ decreased the cell count. The growth reached a maximum level after the second day and started to decrease gradually. The bacterial count at 37/sup 0/C was less than that at 28/sup 0/C. No bacterial multiplication occurred at 44/sup 0/C. There was little difference between heavy metal removal at 28 and 37/sup 0/C. At 44/sup 0/C, little removal took place. In general, slightly acidic or neutral medium was better for both bacterial growth and metal removal.

  8. Detoxification of mercury, cadmium, and lead in Klebsiella aerogenes NCTC 418 growing in continuous culture

    SciTech Connect

    Aiking, H.; Govers, H.; van 'T Riet, J.

    1985-11-01

    Klebsiella aerogenes NCTC 418 growing in the presence of cadmium under glucose-, sulfate-, or phosphate-limited conditions in continuous culture exhibited sulfide formation and P/sub i/ accumulation as the only demonstrable detoxification mechanisms. In the presence of mercury under similar conditions only HgS formation could be confirmed, by an increased sensitivity to mercury under sulfate-limited conditions, among others. The fact that the cells were most sensitive to cadmium under conditions of phosphate limitation and most sensitive to mercury under conditions of sulfate limitation led to the hypothesis that these inorganic detoxification mechanisms generally depended on a kind of facilitated precipitation. The process was coined thus because heavy metals were probably accumulated and precipitated near the cell perimeter due to the relatively high local concentrations of sulfide and phosphate there. Depending on the growth-limiting nutrient, mercury proved to be 25-fold (phosphate limitation), 75-fold (glycerol limitation), or 150-fold (sulfate limitation) more toxic than cadmium to this organism. In the presence of lead, PbS formation was suggested. since no other detoxification mechanisms were detected, for example, rendering heavy metal ions innocuous as metallo-organic compounds, it was concluded that formation of heavy metal precipitates is crucially important to this organism. In addition, it was observed that several components of a defined mineral medium were able to reduce mercuric ions to elemental mercury. This abiotic mercury volatilization was studied in detail, and its general and environmental implications are discussed.

  9. Morphogenesis and patterning of the phallus and cloaca in the American alligator, alligator mississippiensis.

    PubMed

    Gredler, Marissa L; Seifert, Ashley W; Cohn, Martin J

    2015-01-01

    In most animals, reproduction by internal fertilization is facilitated by an intromittent organ, such as the penis in amniote vertebrates. Recent progress has begun to uncover the mechanisms of mammalian external genital development; however, comparatively little is known about the development of the reptilian penis and clitoris. Here, we describe the development of the phallus and cloaca in the American alligator, Alligator mississippiensis. The embryonic precursor of the penis and clitoris is the genital tubercle, which forms by the budding of genital mesenchyme beneath the ventral body wall ectoderm, adjacent to the cloacal membrane. The cloacal lips develop from another pair of outgrowths, the lateral swellings. Early development of the alligator phallus, cloaca, and urogenital ducts generally resembles that of other reptiles, suggesting that differences in adult reptilian phallus and cloacal anatomy arise at later stages. The phallic sulcus is derived from the cloacal endoderm, indicating that the crocodilian sulcus is functionally and developmentally homologous to the mammalian urethra. Initial external genital outgrowth and patterning occur prior to temperature-dependent sex determination. Our analysis of alligator phallus and cloaca development suggests that modifications of an ancestral program of urogenital development could have generated the morphological diversity found in the external genitalia of modern amniotes. PMID:24993090

  10. Genome Sequence of Enterobacter radicincitans DSM16656T, a Plant Growth-Promoting Endophyte

    PubMed Central

    Witzel, Katja; Gwinn-Giglio, Michelle; Nadendla, Suvarna; Shefchek, Kent

    2012-01-01

    Enterobacter radicincitans sp. nov. DSM16656T represents a new species of the genus Enterobacter which is a biological nitrogen-fixing endophytic bacterium with growth-promoting effects on a variety of crop and model plant species. The presence of genes for nitrogen fixation, phosphorous mobilization, and phytohormone production reflects this microbe's potential plant growth-promoting activity. PMID:22965092

  11. Draft Genome Sequence of an Enterobacter Species Associated with Illnesses and Powdered Infant Formula

    PubMed Central

    Jackson, Emily E.; Ogrodzki, Pauline; Pascoe, Ben; Sheppard, Samuel K.

    2016-01-01

    This is the first report of the draft genome sequence of an Enterobacter species that may have been transmitted from powdered infant formula (PIF) to infants, resulting in illness. Enterobacter spp. are currently permitted in PIF, but the transmission of this strain indicates that the microbiological criteria for PIF may need revision. PMID:26769921

  12. Susceptibility of Austrian Clinical Klebsiella and Enterobacter Isolates Linked to Patient-Related Data

    PubMed Central

    Badura, Alexandra; Pregartner, Gudrun; Holzer, Judith C.; Feierl, Gebhard; Grisold, Andrea J.

    2016-01-01

    The aim of the study was to analyze the antimicrobial susceptibility of Austrian clinical Klebsiella sp. and Enterobacter sp. isolates linked to patient-related data over a time period from 1998 to 2014. The main findings of this study were (i) a marked difference of antibiotic susceptibility rates between different infection sites for both Klebsiella sp. and Enterobacter sp., (ii) significantly greater percentages of resistant isolates among both Klebsiella sp. and Enterobacter sp. in male patients compared to female patients and (iii) significantly greater percentages of resistant isolates among both Klebsiella sp. and Enterobacter sp. from hospital-derived samples compared to samples from the community. In conclusion, our statistical data analysis clearly indicated a strong association of patient-related data and Klebsiella sp. and Enterobacter sp. susceptibility profiles. PMID:26903953

  13. Enterobacter xiangfangensis sp. nov., isolated from Chinese traditional sourdough, and reclassification of Enterobacter sacchari Zhu et al. 2013 as Kosakonia sacchari comb. nov.

    PubMed

    Gu, Chun Tao; Li, Chun Yan; Yang, Li Jie; Huo, Gui Cheng

    2014-08-01

    A Gram-stain-negative bacterial strain, 10-17(T), was isolated from traditional sourdough in Heilongjiang Province, China. The bacterium was characterized by a polyphasic approach, including 16S rRNA gene sequence analysis, RNA polymerase β subunit (rpoB) gene sequence analysis, DNA gyrase (gyrB) gene sequence analysis, initiation translation factor 2 (infB) gene sequence analysis, ATP synthase β subunit (atpD) gene sequence analysis, fatty acid methyl ester analysis, determination of DNA G+C content, DNA-DNA hybridization and an analysis of phenotypic features. Strain 10-17(T) was phylogenetically related to Enterobacter hormaechei CIP 103441(T), Enterobacter cancerogenus LMG 2693(T), Enterobacter asburiae JCM 6051(T), Enterobacter mori LMG 25706(T), Enterobacter ludwigii EN-119(T) and Leclercia adecarboxylata LMG 2803(T), having 99.5%, 99.3%, 98.7%, 98.5%, 98.4% and 98.4% 16S rRNA gene sequence similarity, respectively. On the basis of polyphasic characterization data obtained in the present study, a novel species, Enterobacter xiangfangensis sp. nov., is proposed and the type strain is 10-17(T) ( = LMG 27195(T) = NCIMB 14836(T) = CCUG 62994(T)). Enterobacter sacchari Zhu et al. 2013 was reclassified as Kosakonia sacchari comb. nov. on the basis of 16S rRNA, rpoB, gyrB, infB and atpD gene sequence analysis and the type strain is strain SP1(T)( = CGMCC 1.12102(T) = LMG 26783(T)). PMID:24824638

  14. Quorum Sensing Activity of Enterobacter asburiae Isolated from Lettuce Leaves

    PubMed Central

    Lau, Yin Yin; Sulaiman, Joanita; Chen, Jian Woon; Yin, Wai-Fong; Chan, Kok-Gan

    2013-01-01

    Bacterial communication or quorum sensing (QS) is achieved via sensing of QS signaling molecules consisting of oligopeptides in Gram-positive bacteria and N-acyl homoserine lactones (AHL) in most Gram-negative bacteria. In this study, Enterobacteriaceae isolates from Batavia lettuce were screened for AHL production. Enterobacter asburiae, identified by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) was found to produce short chain AHLs. High resolution triple quadrupole liquid chromatography mass spectrometry (LC/MS) analysis of the E. asburiae spent supernatant confirmed the production of N-butanoyl homoserine lactone (C4-HSL) and N–hexanoyl homoserine lactone (C6-HSL). To the best of our knowledge, this is the first report of AHL production by E. asburiae. PMID:24152877

  15. Complete genome sequence of “Enterobacter lignolyticus” SCF1

    SciTech Connect

    DeAngelis, Kristen M.; D'Haeseleer, Patrik; Chivian, Dylan; Fortney, Julian L.; Khudyakov, Jane I.; Simmons, Blake A.; Woo, Hannah; Arkin, Adam P.; Davenport, Karen W.; Goodwin, Lynne A.; Chen, Amy; Ivanova, Natalia; Kyrpides, Nikos C.; Mavromatis, Konstantinos; Woyke, Tanja; Hazen, Terry C.

    2011-09-23

    In an effort to discover anaerobic bacteria capable of lignin degradation, we isolated 'Ente-robacter lignolyticus' SCF1 on minimal media with alkali lignin as the sole source of carbon. This organism was isolated anaerobically from tropical forest soils collected from the Short Cloud Forest site in the El Yunque National Forest in Puerto Rico, USA, part of the Luquillo Long-Term Ecological Research Station. At this site, the soils experience strong fluctuations in redox potential and are net methane producers. Because of its ability to grow on lignin anae-robically, we sequenced the genome. The genome of 'E. lignolyticus' SCF1 is 4.81 Mbp with no detected plasmids, and includes a relatively small arsenal of lignocellulolytic carbohy-drate active enzymes. Lignin degradation was observed in culture, and the genome revealed two putative laccases, a putative peroxidase, and a complete 4-hydroxyphenylacetate degra-dation pathway encoded in a single gene cluster.

  16. Thermal inactivation of Enterobacter sakazakii in rehydrated infant formula.

    PubMed

    Edelson-Mammel, Sharon G; Buchanan, Robert L

    2004-01-01

    The presence of low levels of Enterobacter sakazakii in dried infant formula have been linked to outbreaks of meningitis, septicemia, and necrotizing enterocolitis in neonates, particularly those who are premature or immunocompromised. In the current study, the ability of 12 strains of E. sakazakii to survive heating in rehydrated infant formula was determined at 58 degrees C with a submerged coil apparatus. The observed D58-values ranged from 30.5 to 591.9 s, with the strains appearing to fall into two distinct heat resistance phenotypes. The z-value of the most heat-resistant strain was 5.6 degrees C. When dried infant formula containing this strain was rehydrated with water preequilibrated to various temperatures, a more than 4-log reduction in E. sakazakii levels was achieved by preparing the formula with water at 70 degrees C or greater. PMID:14717352

  17. Kinetic characterization of a novel acid ectophosphatase from Enterobacter asburiae.

    PubMed

    Sato, Vanessa Sayuri; Galdiano Júnior, Renato F; Rodrigues, Gisele Regina; Lemos, Eliana G M; Pizauro Junior, João Martins

    2016-02-01

    Expression of acid ectophosphatase by Enterobacter asburiae, isolated from Cattleya walkeriana (Orchidaceae) roots and identified by the 16S rRNA gene sequencing analysis, was strictly regulated by phosphorus ions, with its optimal activity being observed at an inorganic phosphate concentration of 7 mM. At the optimum pH 3.5, intact cells released p-nitrophenol at a rate of 350.76 ± 13.53 nmol of p-nitrophenolate (pNP)/min/10(8) cells. The membrane-bound enzyme was obtained by centrifugation at 100,000 × g for 1 h at 4 °C. p-Nitrophenylphosphate (pNPP) hydrolysis by the enzyme follows "Michaelis-Menten" kinetics with V = 61.2 U/mg and K0.5 = 60 μM, while ATP hydrolysis showed V = 19.7 U/mg, K0.5 = 110 μM, and nH = 1.6 and pyrophosphate hydrolysis showed V = 29.7 U/mg, K0.5 = 84 μM, and nH = 2.3. Arsenate and phosphate were competitive inhibitors with K i = 0.6 mM and K i = 1.8 mM, respectively. p-Nitrophenyl phosphatase (pNPPase) activity was inhibited by vanadate, while p-hydroxymercuribenzoate, EDTA, calcium, copper, and cobalt had no inhibitory effects. Magnesium ions were stimulatory (K0.5 = 2.2 mM and nH = 0.5). Production of an acid ectophosphatase can be a mechanism for the solubilization of mineral phosphates by microorganisms such as Enterobacter asburiae that are versatile in the solubilization of insoluble minerals, which, in turn, increases the availability of nutrients for plants, particularly in soils that are poor in phosphorus. PMID:26832666

  18. Long Chain N-acyl Homoserine Lactone Production by Enterobacter sp. Isolated from Human Tongue Surfaces

    PubMed Central

    Yin, Wai-Fong; Purmal, Kathiravan; Chin, Shenyang; Chan, Xin-Yue; Chan, Kok-Gan

    2012-01-01

    We report the isolation of N-acyl homoserine lactone-producing Enterobacter sp. isolate T1-1 from the posterior dorsal surfaces of the tongue of a healthy individual. Spent supernatants extract from Enterobacter sp. isolate T1-1 activated the biosensor Agrobacterium tumefaciens NTL4(pZLR4), suggesting production of long chain AHLs by these isolates. High resolution mass spectrometry analysis of these extracts confirmed that Enterobacter sp. isolate T1-1 produced a long chain N-acyl homoserine lactone, namely N-dodecanoyl-homoserine lactone (C12-HSL). To the best of our knowledge, this is the first isolation of Enterobacter sp., strain T1-1 from the posterior dorsal surface of the human tongue and N-acyl homoserine lactones production by this bacterium. PMID:23202161

  19. Fermentation of polysaccharides by Klebsiella and other facultative bacilli

    SciTech Connect

    Ochuba, G.U.; Von Riesen, V.L.

    1980-05-01

    Fermentations of 10 polysaccharides by species of the family Enterobacteriaceae were examined. Algin, guar, karaya, xanthan, and xylan were not fermented by any of the strains tested. Most of the activity was found in the tribe Klebsielleae. Klebseilla oxytoca fermented amylopectin (97% of the strains studied), carrageenan (100%), inulin (68%), polypectate (100%), and tragacanth (100%). Klebsiella pneumoniae fermented amylopectin (91%), carrageenan (100%), and tragacanth (86%). Carraggeenan was also fermented by Enterobacter aerogenes (100%), Enterobacter agglomerans (63%), Enterobacter cloacae (95%), and pectobacterium (38%). pectobacterium shared polypectate fermentation (100%) with K. oxytoca. With one exception, Serratia strains were negative on all polysaccharides. These results, along with other evidence, indicate that (i) the genus Klebsiella is biochemically the most versatile genus of the tribe, (ii) because of its distinct characteristics, K. oxytoca warrants species designation separate from K. pneumoniae, and (iii) some food additives generally considered indigestible can be metabolized by a few species of facultative bacilli, whereas others appear to be resistant.

  20. Enterobacter pulveris sp. nov., isolated from fruit powder, infant formula and an infant formula production environment.

    PubMed

    Stephan, Roger; Van Trappen, Stefanie; Cleenwerck, Ilse; Iversen, Carol; Joosten, Han; De Vos, Paul; Lehner, Angelika

    2008-01-01

    Six Gram-negative, facultatively anaerobic, non-spore-forming, coccoid rod-shaped isolates were obtained from fruit powder (n=3), infant formula (n=2) and an infant formula production environment (n=1) and investigated in a polyphasic taxonomic study. Comparative 16S rRNA gene sequence analysis combined with rpoB gene sequence analysis allocated the isolates to the family Enterobacteriaceae. The highest rpoB gene sequence similarities (91.2-95.8%) were obtained with Enterobacter helveticus, Enterobacter radicincitans, Enterobacter turicensis and Enterobacter sakazakii and the phylogenetic branch formed by these species was supported by a high bootstrap value. Biochemical data revealed that the isolates could be differentiated from their nearest neighbours by their ability to utilize melibiose, sucrose, D-arabitol, mucate and 1-O-methyl-alpha-galactopyranoside and their negative reactions for D-sorbitol utilization and the Voges-Proskauer test. On the basis of the phylogenetic analyses, DNA-DNA hybridization data, and unique physiological and biochemical characteristics, it is proposed that the isolates represent a novel species of the genus Enterobacter, Enterobacter pulveris sp. nov. The type strain is 601/05(T) (=LMG 24057(T)=DSM 19144(T)). PMID:18175715

  1. Vibrio furnissii (formerly aerogenic biogroup of Vibrio fluvialis), a new species isolated from human feces and the environment.

    PubMed Central

    Brenner, D J; Hickman-Brenner, F W; Lee, J V; Steigerwalt, A G; Fanning, G R; Hollis, D G; Farmer, J J; Weaver, R E; Joseph, S W; Seidler, R J

    1983-01-01

    Strains formerly classified as the aerogenic (gas-producing) biogroup of Vibrio fluvialis were shown by DNA relatedness to be a separate species. The species was named Vibrio furnissii sp. nov. (type strain ATCC 35016 = CDC B3215). Three strains of V. furnissii were 79% or more related to the type strain of V. furnissii and about 50% related to the type strain of V. fluvialis. V. fluvialis strains were 40 to 64% related to the type strain of V. furnissii. Divergence in related sequences was only 0.0 to 1.5% among strains of V. furnissii and among strains of V. fluvialis but was 5.0 to 8.0% in interspecific reactions between V. fluvialis and V. furnissii. V. furnissii was aerogenic (produced gas from the fermentation of carbohydrates), whereas V. fluvialis was anaerogenic (did not produce gas from the fermentation of carbohydrates). Another test of some help in differentiating the two species was fermentation of L-rhamnose (57% positive for V. furnissii and negative for V. fluvialis). In addition to the reactions above, V. furnissii is distinguished from other salt-requiring vibrios on the basis of its positive reactions in tests for Møller L-arginine, L-arabinose, maltose, and D-mannitol and its negative reactions for Møller L-lysine and L-ornithine, lactose, and Voges-Proskauer. V. furnissii has been isolated from patients with acute gastroenteritis in at least two outbreaks of food poisoning; its role as a cause of diarrhea needs further study. PMID:6630464

  2. Vibrio furnissii (formerly aerogenic biogroup of Vibrio fluvialis), a new species isolated from human feces and the environment.

    PubMed

    Brenner, D J; Hickman-Brenner, F W; Lee, J V; Steigerwalt, A G; Fanning, G R; Hollis, D G; Farmer, J J; Weaver, R E; Joseph, S W; Seidler, R J

    1983-10-01

    Strains formerly classified as the aerogenic (gas-producing) biogroup of Vibrio fluvialis were shown by DNA relatedness to be a separate species. The species was named Vibrio furnissii sp. nov. (type strain ATCC 35016 = CDC B3215). Three strains of V. furnissii were 79% or more related to the type strain of V. furnissii and about 50% related to the type strain of V. fluvialis. V. fluvialis strains were 40 to 64% related to the type strain of V. furnissii. Divergence in related sequences was only 0.0 to 1.5% among strains of V. furnissii and among strains of V. fluvialis but was 5.0 to 8.0% in interspecific reactions between V. fluvialis and V. furnissii. V. furnissii was aerogenic (produced gas from the fermentation of carbohydrates), whereas V. fluvialis was anaerogenic (did not produce gas from the fermentation of carbohydrates). Another test of some help in differentiating the two species was fermentation of L-rhamnose (57% positive for V. furnissii and negative for V. fluvialis). In addition to the reactions above, V. furnissii is distinguished from other salt-requiring vibrios on the basis of its positive reactions in tests for Møller L-arginine, L-arabinose, maltose, and D-mannitol and its negative reactions for Møller L-lysine and L-ornithine, lactose, and Voges-Proskauer. V. furnissii has been isolated from patients with acute gastroenteritis in at least two outbreaks of food poisoning; its role as a cause of diarrhea needs further study. PMID:6630464

  3. Re-examination of the taxonomic status of Enterobacter helveticus, Enterobacter pulveris and Enterobacter turicensis as members of the genus Cronobacter and their reclassification in the genera Franconibacter gen. nov. and Siccibacter gen. nov. as Franconibacter helveticus comb. nov., Franconibacter pulveris comb. nov. and Siccibacter turicensis comb. nov., respectively

    PubMed Central

    Grim, Christopher J.; Gopinath, Gopal R.; Mammel, Mark K.; Sathyamoorthy, Venugopal; Trach, Larisa H.; Chase, Hannah R.; Fanning, Séamus; Tall, Ben D.

    2014-01-01

    Recently, a taxonomical re-evaluation of the genus Enterobacter, based on multi-locus sequence typing (MLST) analysis, has led to the proposal that the species Enterobacter pulveris, Enterobacter helveticus and Enterobacter turicensis should be reclassified as novel species of the genus Cronobacter. In the present work, new genome-scale analyses, including average nucleotide identity, genome-scale phylogeny and k-mer analysis, coupled with previously reported DNA–DNA hybridization values and biochemical characterization strongly indicate that these three species of the genus Enterobacter are not members of the genus Cronobacter, nor do they belong to the re-evaluated genus Enterobacter. Furthermore, data from this polyphasic study indicated that all three species constitute two new genera. We propose reclassifying Enterobacter pulveris and Enterobacter helveticus in the genus Franconibacter gen. nov. as Franconibacter pulveris comb. nov. (type strain 601/05T = LMG 24057T = DSM 19144T) and Franconibacter helveticus comb. nov. (type strain 513/05T = LMG 23732T = DSM 18396T), respectively, and Enterobacter turicensis in the genus Siccibacter gen. nov. as Siccibacter turicensis comb. nov. (type strain 508/05T = LMG 23730T = DSM 18397T). PMID:25028159

  4. A selective differential medium for Enterobacter sakazakii, a preliminary study.

    PubMed

    Iversen, Carol; Druggan, Patrick; Forsythe, Stephen

    2004-11-01

    Enterobacter sakazakii can cause fatal invasive infection of neonates associated with the presence of this organism in powdered infant milk formula. A new chromogenic medium (Druggan-Forsythe-Iversen agar, DFI) is described for the selective detection of this emergent pathogen. The medium is based on the alpha-glucosidase reaction which is detected using 5-bromo-4-chloro-3-indolyl-alpha,D-glucopyranoside (XalphaGlc). Ent. sakazakii hydrolyses this substrate to an indigo pigment, producing blue-green colonies on this medium. DFI was compared with the current method of detection on violet red bile glucose agar (VRBGA) followed by pigment production on tryptone soy agar (TSA) after 48-72 h at 25 degrees C and subsequent biochemical profile determination using Biomerieux API20E. Ninety-five clinical and food strains of Ent. sakazakii were detected on the DFI chromogenic medium 2 days sooner than the alternative method. The characteristics of 148 strains representing 17 genera of non-Ent. sakazakii Enterobacteriaceae were compared using the two methods. Only 16/18 Escherichia vulneris strains, 2/3 strains of Pantoea spp. and 1/8 Citrobacter koseri strains gave false positive results on DFI agar. Eight alpha-glucosidase positive strains were identified as Pantoea using their API20E biochemical profile, but had higher percentage identification as Ent. sakazakii using ID32E. Therefore the DFI medium enables the detection of Ent. sakazakii within mixed cultures of Enterobacteriaceae, whereas the organism could be missed when using VRBGA since the latter is a general Enterobacteriaceae selective medium. In addition, the common use of API20E to check yellow pigmented colonies on TSA may lead to false negative results and consequently the acceptance of a batch of infant formula milk (IFM) that contains Ent. sakazakii. PMID:15364468

  5. Integrated evaluation of aerogenic pollution by air-transported heavy metals (Pb, Cd, Ni, Zn, Mn and Cu) in the analysis of the main deposit media.

    PubMed

    Baltrėnaitė, Edita; Baltrėnas, Pranas; Lietuvninkas, Arvydas; Serevičienė, Vaida; Zuokaitė, Eglė

    2014-01-01

    The composition of the ambient air is constantly changing; therefore, the monitoring of ambient air quality to detect the changes caused by aerogenic pollutants makes the essential part of general environmental monitoring. To achieve more effective improvement of the ambient air quality, the Directive 2008/50/EC on 'Ambient Air Quality and Cleaner Air for Europe' was adopted by the European Parliament and the European Council. It informed the public and enterprises about a negative effect of pollution on humans, animals and plants, as well as about the need for monitoring aerogenic pollutants not only at the continuous monitoring stations but also by using indicator methods, i.e. by analysing natural deposit media. The problem of determining the relationship between the accumulation level of pollutants by a deposit medium and the level of air pollution and its risks is constantly growing in importance. The paper presents a comprehensive analysis of the response of the main four deposit media, i.e. snow cover, soil, pine bark and epigeic mosses, to the long-term pollution by aerogenic pollutants which can be observed in the area of oil refinery influence. Based on the quantitative expressions of the amounts of the accumulated pollutants in the deposit media, the territory of the oil refinery investigated in this paper has been referred to the areas of mild or moderate pollution. PMID:23933956

  6. Enterobacter spp.: pathogens poised to flourish at the turn of the century.

    PubMed Central

    Sanders, W E; Sanders, C C

    1997-01-01

    Knowledge of the genus Enterobacter and its role in human disease has expanded exponentially in recent years. The incidence of infection in the hospital and the community has increased. New clinical syndromes have been recognized. Enterobacter spp. have also been implicated as causes of other syndromes that traditionally have been associated almost exclusively with more easily treatable pathogens, such as group A streptococci and staphylococci. Rapid emergence of multiple-drug resistance has been documented in individual patients during therapy and in populations and environments with strong selective pressure from antimicrobial agents, especially the cephalosporins. Therapeutic options for patients infected with multiply resistant strains have become severely limited. Carbapenems or, alternatively, fluoroquinolones are the most predictively active options, although resistance to both classes has been observed on rare occasions. Enterobacter spp. appear well adapted for survival and even proliferation as the turn of the century approaches. PMID:9105752

  7. The prevalence of extended-spectrum beta-lactamase in environmental isolates of Enterobacter.

    PubMed

    Sharma, Anjana; Dour, Prashant; Singh, Thakur Nirbhay

    2008-01-01

    The incidence of extended-spectrum beta-lactamase (ESBL)-producing strains and multidrug-resistant strains of Enterobacter spp. isolated from the 1312 km long river Narmada was investigated. Out of the 57 isolates of Enterobacter, 73.68% were found to be ESBL producers including the isolates of E. taylorae and isolates of E. agglomerans, which have been characterized for the first time. All the isolates were found susceptible to the antibiotic imipenem. AmpC gene was found in all the Enterobacter strains tested. AmpC beta-lactamase-producing bacterial pathogens may cause major therapeutic failure if not detected and reported in time. It was seen that these enzymes are mainly chromosomally mediated along with several non-AmpC beta-lactamase. PMID:18417885

  8. Comparison of two multimetal resistant bacterial strains: Enterobacter sp. YSU and Stenotrophomonas maltophilia ORO2.

    PubMed

    Holmes, Andrew; Vinayak, Anubhav; Benton, Cherise; Esbenshade, Aaron; Heinselman, Carlisle; Frankland, Daniel; Kulkarni, Samatha; Kurtanich, Adrienne; Caguiat, Jonathan

    2009-11-01

    The Y-12 plant in Oak Ridge, TN, which manufactured nuclear weapons during World War II and the Cold War, contaminated East Fork Poplar Creek with heavy metals. The multimetal resistant bacterial strain, Stenotrophomonas maltophilia Oak Ridge strain O2 (S. maltophilia O2), was isolated from East Fork Poplar Creek. Sequence analysis of 16s rDNA suggested that our working strain of S. maltophilia O2 was a strain of Enterobacter. Phylogenetic tree analysis and biochemical tests confirmed that it belonged to an Enterobacter species. This new strain was named Enterobacter sp. YSU. Using a modified R3A growth medium, R3A-Tris, the Hg(II), Cd(II), Zn(II), Cu(II), Au(III), Cr(VI), Ag(I), As(III), and Se(IV) MICs for a confirmed strain of S. maltophilia O2 were 0.24, 0.33, 5, 5, 0.25, 7, 0.03, 14, and 40 mM, respectively, compared to 0.07, 0.24, 0.8, 3, 0.05, 0.4, 0.08, 14, and 40 mM, respectively, for Enterobacter sp. YSU. Although S. maltophilia O2 was generally more metal resistant than Enterobacter sp. YSU, in comparison to Escherichia coli strain HB101, Enterobacter sp. YSU was resistant to Hg(II), Cd(II), Zn(II), Au(III), Ag(I), As(III), and Se(IV). By studying metal resistances in these two strains, it may be possible to understand what makes one microorganism more metal resistant than another microorganism. This work also provided benchmark MICs that can be used to evaluate the metal resistance properties of other bacterial isolates from East Fork Poplar Creek and other metal contaminated sites. PMID:19688378

  9. Whole-Genome Sequence of Enterobacter sp. Strain SST3, an Endophyte Isolated from Jamaican Sugarcane (Saccharum sp.) Stalk Tissue

    PubMed Central

    Gan, Han Ming; McGroty, Sean E.; Chew, Teong Han; Chan, Kok Gan; Buckley, Larry J.; Savka, Michael A.

    2012-01-01

    Enterobacter sp. strain SST3 is an endophytic bacterium isolated from Saccharum spp. Here we present its annotated draft genome that may shed light on its role as a bacterial endophyte of sugarcane. To our knowledge, this is the first genome announcement of a sugarcane-associated bacterium from the genus Enterobacter. PMID:23045495

  10. Dechlorination of 1,1,1-Trichloro-2,2-bis(p-chlorophenyl)ethane by Aerobacter aerogenes

    USGS Publications Warehouse

    Wedemeyer, Gary

    1967-01-01

    Whole cells or cell-free extracts of Aerobacter aerogenes catalyze the degradation of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) in vitro to at least seven metabolites: 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE); 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD); 1-chloro-2,2-bis(p-chlorophenyl)ethylene (DDMU); 1-chloro-2,2-bis(p-chlorophenyl)ethane (DDMS); unsym-bis(p-chlorophenyl)ethylene (DDNU); 2,2-bis(p-chlorophenyl)acetate (DDA); and 4,4′-dichlorobenzophenone (DBP). The use of metabolic inhibitors together with pH and temperature studies indicated that discrete enzymes are involved. By use of the technique of sequential analysis, the metabolic pathway was shown to be: DDT → DDD →DDMU →DDMS → DDNU → DDA → DBP, or DDT → DDE. Dechlorination was marginally enhanced by light-activated flavin mononucleotide.

  11. Role of the nac gene product in the nitrogen regulation of some NTR-regulated operons of Klebsiella aerogenes.

    PubMed

    Macaluso, A; Best, E A; Bender, R A

    1990-12-01

    A positive, genetic selection against the activity of the nitrogen regulatory (NTR) system was used to isolate insertion mutations affecting nitrogen regulation in Klebsiella aerogenes. Two classes of mutation were obtained: those affecting the NTR system itself and leading to the loss of almost all nitrogen regulation, and those affecting the nac locus and leading to a loss of nitrogen regulation of a family of nitrogen-regulated enzymes. The set of these nac-dependent enzymes included histidase, glutamate dehydrogenase, glutamate synthase, proline oxidase, and urease. The enzymes shown to be nac independent included glutamine synthetase, asparaginase, tryptophan permease, nitrate reductase, the product of the nifLA operon, and perhaps nitrite reductase. The expression of the nac gene was itself highly nitrogen regulated, and this regulation was mediated by the NTR system. The loss of nitrogen regulation was found in each of the four insertion mutants studied, showing that loss of nitrogen regulation resulted from the absence of nac function rather than from an altered form of the nac gene product. Thus we propose two classes of nitrogen-regulated operons: in class I, the NTR system directly activates expression of the operon; in class II, the NTR system activates nac expression and the product(s) of the nac locus activates expression of the operon. PMID:1979323

  12. Gross anatomical features of the gastrointestinal tract (GIT) of blue-and-yellow macaws (Ara ararauna) - oesophagus to cloaca.

    PubMed

    Aizawa, J; Tivane, C; Rodrigues, M N; Wagner, P G; Campos, D B; Guerra, R R; Miglino, M A

    2013-12-01

    Morphological studies of the gastrointestinal tract of blue-and-yellow macaws (Ara ararauna) are scarce. In view of the paucity of information regarding the digestive tract of macaws, this study aims to describe the gross anatomical features (oesophagus to cloaca) as part of a broad study of the gastrointestinal tract (GIT) of these birds. Three animals (two males and one female) adult macaws were anatomically dissected from the oropharynx to the cloaca to expose the GIT. The oesophagus was identified as a muscle-membranous tube continuous with the crop, which was intimately attached to the skin. The internal longitudinal folds of the cervical oesophagus were sparser cranial to the crop and less evident compared to the portion caudal to the crop. The duodenum began in the pylorus and was grey-coloured exhibiting a large lumen. The jejunum was formed by loops in a spiral-fashion model supported by mesojejunum. The ileum was also composed by small loops and was continuous with the colo-rectum forming the large intestine, because the caeca were absent. The large intestine was short, median in position, suspended in the dorsal wall of the abdominal cavity by mesentery and ended in the cloaca. The GIT was similar to the basic patterns in birds, in general, and also presented new unreported morphological data that might be important when studying nutrition and health of the macaws. PMID:23414512

  13. Dkk1 in the Peri-Cloaca Mesenchyme Regulates Formation of Anorectal and Genitourinary Tracts

    PubMed Central

    MacDonald, Bryan T.; Borer, Joseph G.; Li, Xue

    2013-01-01

    Anorectal malformation (ARM) is a common birth defect but the developmental history and the underlying molecular mechanism are poorly understood. Using murine genetic models, we report here that a signaling molecule Dickkopf-1 (Dkk1) is a critical regulator. The anorectal and genitourinary tracts are major derivatives of caudal hindgut, or the cloaca. Dkk1 is highly expressed in the dorsal peri-cloacal mesenchymal (dPCM) progenitors. We show that deletion of Dkk1 causes the imperforate anus with rectourinary fistula. Mutant genital tubercles exhibit a preputial hypospadias phenotype and premature urethral canalization. Dkk1 mutants have an ectopic expansion of the dPCM tissue, which correlates with an aberrant increase of cell proliferation and survival. This ectopic tissue is detectable before the earliest sign of the anus formation, suggesting that it is most likely the primary or early cause of the defect. Deletion of Dkk1 results in an elevation of the Wnt/ß-catenin activity. Signaling molecules Shh, Fgf8 and Bmp4 are also upregulated. Furthermore, genetic hyperactivation of Wnt/ß-catenin signal pathway in the cloacal mesenchyme partially recapitulates Dkk1 mutant phenotypes. Together, these findings underscore the importance of DKK1 in regulating behavior of dPCM progenitors, and suggest that formation of anus and urethral depends on Dkk1-mediated dynamic inhibition of the canonical Wnt/ß-catenin signal pathway. PMID:24479159

  14. Development of the cloaca, hemipenes, and hemiclitores in the green anole, Anolis carolinensis.

    PubMed

    Gredler, Marissa L; Sanger, Thomas J; Cohn, Martin J

    2015-01-01

    In most amniotes, the intromittent organ is a single phallus; however, squamates (lizards, snakes, and amphisbaenians) have paired hemiphalluses. All amniotes studied to date initiate external genital development with the formation of paired genital swellings. In mammals, archosaurs, and turtles, these swellings merge to form a single genital tubercle, the precursor of the penis and clitoris; however, in squamates, the paired genital buds remain separate, giving rise to the hemiphalluses (hemipenes in males and hemiclitores in females). Although the molecular genetics and sexual differentiation of the genital tubercle have been investigated in mammals and birds, little is known about hemiphallus development. Here we describe development of the cloaca and hemiphallus in the green anole, Anolis carolinensis. Each hemiphallus originates as a protuberance that emerges at the ventral base of the hindlimb bud. Development of the hemipenes resembles penis development; however, differences exist in their tissue composition, morphogenesis, and gene expression patterns. These findings reveal aspects of phallus development that appear to be evolutionarily labile, both within squamates and more broadly among reptiles, and identify features that are conserved across amniotes. Our results, together with parallel studies in other reptilian taxa, suggest potential mechanisms for the diversification of external genital form. PMID:24960313

  15. [From the Cloaca Maxima to current sewage treatment works--historical aspects of waste disposal].

    PubMed

    Schadewaldt, H

    1983-09-01

    According to calculations made by the well-known hygienist Max Rubner in 1890, the annual quantity of waste made up of excreta, urine, kitchen refuse, ashes and water for general use than ran to 7,300 kgs. Thus it appears quite obvious that as early as in the ancient high cultures special waste disposal plants existed. In the Old Testament cesspools were in use, in Ancient Egypt sliding boxes served the same purpose, the Cretan palace of Knossos was provided with a really sophisticated water closet system and there is evidence that a similar facility existed in Mesopotamia. The Roman Cloaca maxima which functioned as a sanitary system for the entire capital, has never ceased to impress. With the advent of the so-called "miasma theory", public health legislations also started to take care of waste disposal, and as a result, various lavatories, slaughter-house and waste water facilities were created. When bacteriology began to establish itself, close attention was devoted to the ground water and the rivers. The "squatting closet" in Roman countries contrasted with the flush closet in England. For waste disposal, the so-called "Heidelberg barrel system" or the "Kiel exchange bucket system" were introduced. Of more recent date are the digestion chambers, the flow settling tanks and the "trickling or oxydation system" on the sprinkling fields. PMID:6359782

  16. Inactivation of Enterobacter sakazakii by Water-soluble Muscadine Seed Extracts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hot and cold water-soluble muscadine (Vitis rotundifolia) seed extracts and their polar and polyphenol fractions from two Muscadine cultivars (‘Ison’, purple and ‘Carlos’, bronze) were investigated for their inhibition of Enterobacter sakazakii. The heat treatment on each seed extract not only incre...

  17. Microarray-based Comparative Genomic Indexing of the Cronobacter genus (Enterobacter sakazakii)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cronobacter is a recently defined genus synonymous with Enterobacter sakazakii. This new genus currently comprises 6 genomospecies. To extend our understanding of the genetic relationship between Cronobacter sakazakii BAA-894 and the other species of this genus, microarray-based comparative genomi...

  18. Draft Genome Sequence of Enterobacter sp. Strain UCD-UG_FMILLET (Phylum Proteobacteria)

    PubMed Central

    Ettinger, Cassandra L.; Mousa, Walaa M.; Raizada, Manish N.

    2015-01-01

    Here, we present the draft genome of Enterobacter sp. strain UCD-UG_FMILLET. This strain is an endophyte isolated from the roots of finger millet, an Afro-Indian cereal crop. The genome contains 4,801,411 bp in 53 scaffolds. PMID:25614569

  19. Bacterial cellulose synthesis mechanism of facultative anaerobe Enterobacter sp. FY-07.

    PubMed

    Ji, Kaihua; Wang, Wei; Zeng, Bing; Chen, Sibin; Zhao, Qianqian; Chen, Yueqing; Li, Guoqiang; Ma, Ting

    2016-01-01

    Enterobacter sp. FY-07 can produce bacterial cellulose (BC) under aerobic and anaerobic conditions. Three potential BC synthesis gene clusters (bcsI, bcsII and bcsIII) of Enterobacter sp. FY-07 have been predicted using genome sequencing and comparative genome analysis, in which bcsIII was confirmed as the main contributor to BC synthesis by gene knockout and functional reconstitution methods. Protein homology, gene arrangement and gene constitution analysis indicated that bcsIII had high identity to the bcsI operon of Enterobacter sp. 638; however, its arrangement and composition were same as those of BC synthesizing operon of G. xylinum ATCC53582 except for the flanking sequences. According to the BC biosynthesizing process, oxygen is not directly involved in the reactions of BC synthesis, however, energy is required to activate intermediate metabolites and synthesize the activator, c-di-GMP. Comparative transcriptome and metabolite quantitative analysis demonstrated that under anaerobic conditions genes involved in the TCA cycle were downregulated, however, genes in the nitrate reduction and gluconeogenesis pathways were upregulated, especially, genes in three pyruvate metabolism pathways. These results suggested that Enterobacter sp. FY-07 could produce energy efficiently under anaerobic conditions to meet the requirement of BC biosynthesis. PMID:26911736

  20. Bacterial cellulose synthesis mechanism of facultative anaerobe Enterobacter sp. FY-07

    PubMed Central

    Ji, Kaihua; Wang, Wei; Zeng, Bing; Chen, Sibin; Zhao, Qianqian; Chen, Yueqing; Li, Guoqiang; Ma, Ting

    2016-01-01

    Enterobacter sp. FY-07 can produce bacterial cellulose (BC) under aerobic and anaerobic conditions. Three potential BC synthesis gene clusters (bcsI, bcsII and bcsIII) of Enterobacter sp. FY-07 have been predicted using genome sequencing and comparative genome analysis, in which bcsIII was confirmed as the main contributor to BC synthesis by gene knockout and functional reconstitution methods. Protein homology, gene arrangement and gene constitution analysis indicated that bcsIII had high identity to the bcsI operon of Enterobacter sp. 638; however, its arrangement and composition were same as those of BC synthesizing operon of G. xylinum ATCC53582 except for the flanking sequences. According to the BC biosynthesizing process, oxygen is not directly involved in the reactions of BC synthesis, however, energy is required to activate intermediate metabolites and synthesize the activator, c-di-GMP. Comparative transcriptome and metabolite quantitative analysis demonstrated that under anaerobic conditions genes involved in the TCA cycle were downregulated, however, genes in the nitrate reduction and gluconeogenesis pathways were upregulated, especially, genes in three pyruvate metabolism pathways. These results suggested that Enterobacter sp. FY-07 could produce energy efficiently under anaerobic conditions to meet the requirement of BC biosynthesis. PMID:26911736

  1. The status of the species Enterobacter siamensisKhunthongpan et al. 2014. Request for an Opinion.

    PubMed

    Kämpfer, Peter; Doijad, Swapnil; Chakraborty, Trinad; Glaeser, Stefanie P

    2016-01-01

    In the course of a taxonomic study describing novel species of the genus Enterobacter it was found that the 16S rRNA gene sequence of the type strain of Enterobacter siamensis, obtained both directly from the authors of the publication on Enterobacter siamensis and from the Korean Collection for Type Cultures (C2361T and KCTC 23282T, respectively), was not congruent with the 16S rRNA gene sequence deposited in the GenBank database under the accession number HQ888848, which was applied for phylogenetic analysis in the species proposal. The remaining deposit in the Japanese type culture collection, NBRC 107138T, showed an identical 16S rRNA gene sequence to the other two cultures and overall, this sequence differed at 35 positions in comparison with the 1429 bp sequence published under the accession number HQ888848.Therefore, the type strain of this species cannot be included in any further scientific comparative study. It is proposed that the Judicial Commission of the International Committee on Systematics of Prokaryotes place the name Enterobacter siamensis on the list of rejected names, if a suitable replacement for the type strain is not found or a neotype strain is not proposed within two years following the publication of this Request for an Opinion. PMID:26581210

  2. Activity of Eravacycline against Enterobacteriaceae and Acinetobacter baumannii, Including Multidrug-Resistant Isolates, from New York City

    PubMed Central

    Abdallah, Marie; Olafisoye, Olawole; Cortes, Christopher; Urban, Carl; Landman, David

    2014-01-01

    Eravacycline demonstrated in vitro activity against a contemporary collection of more than 4,000 Gram-negative pathogens from New York City hospitals, with MIC50/MIC90 values, respectively, for Escherichia coli of 0.12/0.5 μg/ml, Klebsiella pneumoniae of 0.25/1 μg/ml, Enterobacter aerogenes of 0.25/1 μg/ml, Enterobacter cloacae 0.5/1 μg/ml, and Acinetobacter baumannii of 0.5/1 μg/ml. Activity was retained against multidrug-resistant isolates, including those expressing KPC and OXA carbapenemases. For A. baumannii, eravacycline MICs correlated with increased expression of the adeB gene. PMID:25534744

  3. Antimicrobial and cytotoxic activities from Jatropha dioica roots.

    PubMed

    Silva-Belmares, Yesenia; Rivas-Morales, Catalina; Viveros-Valdez, Ezequiel; de la Cruz-Galicia, María Guadalupe; Carranza-Rosales, Pilar

    2014-05-01

    The antimicrobial and cytotoxic activities of organic extracts obtained from roots of the medicinal plant Jatropha dioica (Euphorbiaceae) were investigated. In order to evaluate their antimicrobial activity, the organic extracts were tested against clinical isolates of the human pathogens Bacillus cereus, Escherichia coli, Salmonella typhi, Staphylococcus aureus, Enterobacter aerogenes, Enterobacter cloacae, Salmonella typhimurium, Cryptococcus neoformans, Candida albicans, Candida parapsilosis and Sporothrix schenckii. Results revealed that the hexane extract possess the stronger activity and a broader microbicide spectrum compared to the acetone and ethanol extracts. The activity of hexane extract may be attributed in part to the presence of β-sitosterol, the major compound identified by bioautography. The hexane extract, as well as the bioactive fraction were not cytotoxic when assays were profiled against the normal cell lines Chang, OK and LLCPK-1 (IC50>1000 μg mL(-1)). PMID:26031013

  4. Chemical composition and antibacterial activity of Lavandula coronopifolia essential oil against antibiotic-resistant bacteria.

    PubMed

    Ait Said, L; Zahlane, K; Ghalbane, I; El Messoussi, S; Romane, A; Cavaleiro, C; Salgueiro, L

    2015-01-01

    The aim of this study was to analyse the composition of the essential oil (EO) of Lavandula coronopifolia from Morocco and to evaluate its in vitro antibacterial activity against antibiotic-resistant bacteria isolated from clinical infections. The antimicrobial activity was assessed by a broth micro-well dilution method using multiresistant clinical isolates of 11 pathogenic bacteria: Klebsiella pneumoniae subsp. pneumoniae, Klebsiella ornithinolytica, Escherichia coli, Enterobacter cloacae, Enterobacter aerogenes, Providencia rettgeri, Citrobacter freundii, Hafnia alvei, Salmonella spp., Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus. The main compounds of the oil were carvacrol (48.9%), E-caryophyllene (10.8%) and caryophyllene oxide (7.7%). The oil showed activity against all tested strains with minimal inhibitory concentration (MIC) values ranging between 1% and 4%. For most of the strains, the MIC value was equivalent to the minimal bactericidal concentration value, indicating a clear bactericidal effect of L. coronopifolia EO. PMID:25174508

  5. Estimation of cultivable bacterial diversity in the cloacae and pharynx in Eurasian griffon vultures (Gyps fulvus).

    PubMed

    Vela, Ana I; Casas-Díaz, Encarna; Fernández-Garayzábal, José F; Serrano, Emmanuel; Agustí, Susana; Porrero, María C; Sánchez del Rey, Verónica; Marco, Ignasi; Lavín, Santiago; Domínguez, Lucas

    2015-04-01

    In this work, we describe the biodiversity of cloacal and pharynx culture-based bacteria (commensal and pathogenic), in 75 Eurasian griffon vultures (Gyps fulvus) from two geographic areas. We address the question of whether the cultivable microbiota of vultures is organised into assemblages occurring by chance. In addition, we assess bacterial diversity in both anatomic regions and geographic areas. Bacterial diversity was represented by 26 Gram-negative and 20 Gram-positive genera. The most common genera were Escherichia, Enterococcus, Staphylococcus, Clostridium and Lactococcus. Escherichia coli and Enterococcus faecalis were the most common species in cloacal and pharyngeal samples. Staphylococcus and Erysipelothrix were isolated from the pharynx and Salmonella and Corynebacterium from the cloacae, and no Campylobacter was isolated from the cloacal swabs. Ten cloacal swabs were positive for Salmonella, of which five isolates were Salmonella enterica serotype 4,(5),12:i:-, one isolate was S. enterica serotype Derby, three isolates were S. enterica serotype 61:k:1,5,7 and one isolate was S. enterica serotype Infantis. The null modelling approach revealed that the commensal bacteria of vultures are not structured in assemblages. On the other hand, differences in bacterial genus and species richness between cloacal and pharyngeal samples or between geographic areas were clear, with the pharynx in vultures from both geographic areas being richer. The results of this study indicate also that vultures can serve as a reservoir of certain pathogenic zoonotic bacteria. The dissemination of these zoonotic pathogens in wildlife could be prevented by periodic sanitary surveys. PMID:25388757

  6. Disruption of the temporally regulated cloaca endodermal β-catenin signaling causes anorectal malformations

    PubMed Central

    Miyagawa, S; Harada, M; Matsumaru, D; Tanaka, K; Inoue, C; Nakahara, C; Haraguchi, R; Matsushita, S; Suzuki, K; Nakagata, N; Ng, R C-L; Akita, K; Lui, V C-H; Yamada, G

    2014-01-01

    The cloaca is temporally formed and eventually divided by the urorectal septum (URS) during urogenital and anorectal organ development. Although congenital malformations, such as anorectal malformations (ARMs), are frequently observed during this process, the underlying pathogenic mechanisms remain unclear. β-Catenin is a critical component of canonical Wnt signaling and is essential for the regulation of cell differentiation and morphogenesis during embryogenesis. The expression of β-catenin is observed in endodermal epithelia, including URS epithelia. We modulated the β-catenin gene conditionally in endodermal epithelia by utilizing tamoxifen-inducible Cre driver line (ShhCreERT2). Both β-catenin loss- and gain-of-function (LOF and GOF) mutants displayed abnormal clefts in the perineal region and hypoplastic elongation of the URS. The mutants also displayed reduced cell proliferation in the URS mesenchyme. In addition, the β-catenin GOF mutants displayed reduced apoptosis and subsequently increased apoptosis in the URS epithelium. This instability possibly resulted in reduced expression levels of differentiation markers, such as keratin 1 and filaggrin, in the perineal epithelia. The expression of bone morphogenetic protein (Bmp) genes, such as Bmp4 and Bmp7, was also ectopically induced in the epithelia of the URS in the β-catenin GOF mutants. The expression of the Msx2 gene and phosphorylated-Smad1/5/8, possible readouts of Bmp signaling, was also increased in the mutants. Moreover, we introduced an additional mutation for a Bmp receptor gene: BmprIA. The ShhCreERT2/+; β-cateninflox(ex3)/+; BmprIAflox/− mutants displayed partial restoration of URS elongation compared with the β-catenin GOF mutants. These results indicate that some ARM phenotypes in the β-catenin GOF mutants were caused by abnormal Bmp signaling. The current analysis revealed the close relation of endodermal β-catenin signaling to the ARM phenotypes. These results are considered to

  7. Genome Sequence of the Plant Growth Promoting Endophytic Bacterium Enterobacter sp. 638

    SciTech Connect

    Taghavi, S.; van der Lelie, D.; Hoffman, A.; Zhang, Y.-B.; Walla, M. D.; Vangronsveld, J.; Newman, L.; Monchy, S.

    2010-05-13

    Enterobacter sp. 638 is an endophytic plant growth promoting gamma-proteobacterium that was isolated from the stem of poplar (Populus trichocarpa x deltoides cv. H11-11), a potentially important biofuel feed stock plant. The Enterobacter sp. 638 genome sequence reveals the presence of a 4,518,712 bp chromosome and a 157,749 bp plasmid (pENT638-1). Genome annotation and comparative genomics allowed the identification of an extended set of genes specific to the plant niche adaptation of this bacterium. This includes genes that code for putative proteins involved in survival in the rhizosphere (to cope with oxidative stress or uptake of nutrients released by plant roots), root adhesion (pili, adhesion, hemagglutinin, cellulose biosynthesis), colonization/establishment inside the plant (chemiotaxis, flagella, cellobiose phosphorylase), plant protection against fungal and bacterial infections (siderophore production and synthesis of the antimicrobial compounds 4-hydroxybenzoate and 2-phenylethanol), and improved poplar growth and development through the production of the phytohormones indole acetic acid, acetoin, and 2,3-butanediol. Metabolite analysis confirmed by quantitative RT-PCR showed that, the production of acetoin and 2,3-butanediol is induced by the presence of sucrose in the growth medium. Interestingly, both the genetic determinants required for sucrose metabolism and the synthesis of acetoin and 2,3-butanediol are clustered on a genomic island. These findings point to a close interaction between Enterobacter sp. 638 and its poplar host, where the availability of sucrose, a major plant sugar, affects the synthesis of plant growth promoting phytohormones by the endophytic bacterium. The availability of the genome sequence, combined with metabolome and transcriptome analysis, will provide a better understanding of the synergistic interactions between poplar and its growth promoting endophyte Enterobacter sp. 638. This information can be further exploited to

  8. Bioethanol production from mannitol by a newly isolated bacterium, Enterobacter sp. JMP3.

    PubMed

    Wang, Jing; Kim, Young Mi; Rhee, Hong Soon; Lee, Min Woo; Park, Jong Moon

    2013-05-01

    In this study a new bacterium capable of growing on brown seaweed Laminaria japonica, Enterobacter sp. JMP3 was isolated from the gut of turban shell, Batillus cornutus. In anaerobic condition, it produced high yields of ethanol (1.15 mol-EtOH mol-mannitol(-1)) as well as organic acids from mannitol, the major carbohydrate component of L. japonica. Based on carbon distribution and metabolic flux analysis, it was revealed that mannitol was more favorable than glucose for ethanol production due to their different redox states. This indicates that L. japonica is one of the promising feedstock for bioethanol production. Additionally, the mannitol dehydrogenation pathway in Enterobacter sp. JMP3 was examined and verified. Finally, an attempt was made to explore the possibility of controlling ethanol production by altering the redox potential via addition of external NADH in mannitol fermentation. PMID:23186687

  9. Dysregulation of Wnt inhibitory factor 1 (Wif1) expression resulted in aberrant Wnt-β-catenin signaling and cell death of the cloaca endoderm, and anorectal malformations

    PubMed Central

    Ng, R C-L; Matsumaru, D; Ho, A S-H; Garcia-Barceló, M-M; Yuan, Z-W; Smith, D; Kodjabachian, L; Tam, P K-H; Yamada, G; Lui, V C-H

    2014-01-01

    In mammalian urorectal development, the urorectal septum (urs) descends from the ventral body wall to the cloaca membrane (cm) to partition the cloaca into urogenital sinus and rectum. Defective urs growth results in human congenital anorectal malformations (ARMs), and their pathogenic mechanisms are unclear. Recent studies only focused on the importance of urs mesenchyme proliferation, which is induced by endoderm-derived Sonic Hedgehog (Shh). Here, we showed that the programmed cell death of the apical urs and proximal cm endoderm is particularly crucial for the growth of urs during septation. The apoptotic endoderm was closely associated with the tempo-spatial expression of Wnt inhibitory factor 1 (Wif1), which is an inhibitor of Wnt-β-catenin signaling. In Wif1lacZ/lacZ mutant mice and cultured urorectum with exogenous Wif1, cloaca septation was defective with undescended urs and hypospadias-like phenotypes, and such septation defects were also observed in Shh−/− mutants and in endodermal β-catenin gain-of-function (GOF) mutants. In addition, Wif1 and Shh were expressed in a complementary manner in the cloaca endoderm, and Wif1 was ectopically expressed in the urs and cm associated with excessive endodermal apoptosis and septation defects in Shh−/− mutants. Furthermore, apoptotic cells were markedly reduced in the endodermal β-catenin GOF mutant embryos, which counteracted the inhibitory effects of Wif1. Taken altogether, these data suggest that regulated expression of Wif1 is critical for the growth of the urs during cloaca septation. Hence, Wif1 governs cell apoptosis of urs endoderm by repressing β-catenin signal, which may facilitate the protrusion of the underlying proliferating mesenchymal cells towards the cm for cloaca septation. Dysregulation of this endodermal Shh-Wif1-β-catenin signaling axis contributes to ARM pathogenesis. PMID:24632949

  10. Genome Sequence of the Plant Growth Promoting Endophytic Bacterium Enterobacter sp. 638

    PubMed Central

    Taghavi, Safiyh; van der Lelie, Daniel; Hoffman, Adam; Zhang, Yian-Biao; Walla, Michael D.; Vangronsveld, Jaco; Newman, Lee; Monchy, Sébastien

    2010-01-01

    Enterobacter sp. 638 is an endophytic plant growth promoting gamma-proteobacterium that was isolated from the stem of poplar (Populus trichocarpa×deltoides cv. H11-11), a potentially important biofuel feed stock plant. The Enterobacter sp. 638 genome sequence reveals the presence of a 4,518,712 bp chromosome and a 157,749 bp plasmid (pENT638-1). Genome annotation and comparative genomics allowed the identification of an extended set of genes specific to the plant niche adaptation of this bacterium. This includes genes that code for putative proteins involved in survival in the rhizosphere (to cope with oxidative stress or uptake of nutrients released by plant roots), root adhesion (pili, adhesion, hemagglutinin, cellulose biosynthesis), colonization/establishment inside the plant (chemiotaxis, flagella, cellobiose phosphorylase), plant protection against fungal and bacterial infections (siderophore production and synthesis of the antimicrobial compounds 4-hydroxybenzoate and 2-phenylethanol), and improved poplar growth and development through the production of the phytohormones indole acetic acid, acetoin, and 2,3-butanediol. Metabolite analysis confirmed by quantitative RT–PCR showed that, the production of acetoin and 2,3-butanediol is induced by the presence of sucrose in the growth medium. Interestingly, both the genetic determinants required for sucrose metabolism and the synthesis of acetoin and 2,3-butanediol are clustered on a genomic island. These findings point to a close interaction between Enterobacter sp. 638 and its poplar host, where the availability of sucrose, a major plant sugar, affects the synthesis of plant growth promoting phytohormones by the endophytic bacterium. The availability of the genome sequence, combined with metabolome and transcriptome analysis, will provide a better understanding of the synergistic interactions between poplar and its growth promoting endophyte Enterobacter sp. 638. This information can be further exploited to

  11. Investigation of FGF10 as a candidate gene in patients with anorectal malformations and exstrophy of the cloaca.

    PubMed

    Krüger, Victoria; Khoshvaghti, Mercedeh; Reutter, Heiko; Vogt, Hannes; Boemers, Thomas M; Ludwig, Michael

    2008-08-01

    The spectrum of anorectal malformations (ARM) comprises anal stenosis, ectopic anus, recto-urogenital fistula, persistent cloaca, multisystem VACTERL (VATER associations including cardiac and limb anomalies) associations, and exstrophy of the cloaca (CE). The latter also constitutes the most severe form of the bladder exstrophy epispadias complex. Since recent data revealed that fibroblast growth factor 10 (fgf-10) invalidation in mice resulted in a genetically reproducible urorectal defect, we considered FGF10 a suitable candidate gene for ARM and CE, as the protein seems to be involved in the development of this primary developmental field. A total of 20 patients (ten with ARM and VACTERL association, respectively, and ten with CE) were analysed for genomic mutations in the coding regions and exon-intron boundaries of FGF10. Aside from a common FGF10 variant no deviation from the wild-type sequence could be detected and data obtained is not supportive of FGF10 as a genetic cause of ARMs or CE in the patients investigated. Nonetheless, mutations in possibly further upstream located promoter regions and/or unknown regulatory sequences or non-coding regions cannot be excluded. Furthermore, it cannot be ruled out that other genes involved in the signalling pathway of FGF10 may contribute to the formation of these congenital malformations. PMID:18587586

  12. Inoculation of hybrid poplar with the endophytic bacterium Enterobacter sp. 638 increases biomass but does not impact leaf level physiology

    SciTech Connect

    Rogers, A.; McDonald, K.; Muehlbauer, M. F.; Hoffman, A.; Koenig, K.; Newman, L.; Taghavi, S.; Van Der Lelie, D.

    2011-01-01

    Endophytic bacteria have been shown to provide several advantages to their host, including enhanced growth. Inoculating biofuel species with endophytic bacteria is therefore an attractive option to increase the productivity of biofuel feedstocks. Here, we investigated the effect of inoculating hard wood cuttings of Populus deltoides Bartr. x Populus. nigra L. clone OP367 with Enterobacter sp. 638. After 17 weeks, plants inoculated with Enterobacter sp. 638 had 55% greater total biomass than un-inoculated control plants. Study of gas exchange and fluorescence in developing and mature leaves over a diurnal cycle and over a 5 week measurement campaign revealed no effects of inoculation on photosynthesis, stomatal conductance, photosynthetic water use efficiency or the maximum and operating efficiency of photosystem II. However, plants inoculated with Enterobacter sp. 638 had a canopy that was 39% larger than control plants indicating that the enhanced growth was fueled by increased leaf area, not by improved physiology. Leaf nitrogen content was determined at two stages over the 5 week measurement period. No effect of Enterobacter sp. 638 on leaf nitrogen content was found indicating that the larger plants were acquiring sufficient nitrogen. Enterobacter sp. 638 lacks the genes for N{sub 2} fixation, therefore the increased availability of nitrogen likely resulted from enhanced nitrogen acquisition by the 84% larger root system. These data show that Enterobacter sp. 638 has the potential to dramatically increase productivity in poplar. If fully realized in the production environment, these results indicate that an increase in the environmental and economic viability of poplar as a biofuel feedstock is possible when inoculated with endophytic bacteria like Enterobacter sp. 638.

  13. Enterobacteriaceae in mouth and cloaca of podocnemis expansa and P. Unifilis (testudines: chelonia) populations of national park of araguaia plains, Brazil

    PubMed Central

    de Morais, Paula Benevides; de Souza, Denise Rodrigues; de Sousa, Francisca Maria Pinheiro; de Oliveira, Kleverson Wessel; Pimenta, Raphael Sanzio

    2011-01-01

    Shigella flexnerii and Escherichia coli were the most frequent Gram-negative bacteria found in the mouth cavity and cloacae of the turtles Podocnemis expansa and P. unifilis on beaches in the National Park of Araguaia, Brazil. Reptiles are known as Salmonella carriers, despite rarely isolated in these turtles. PMID:24031664

  14. EFFECT OF BOTANICAL PROBIOTIC CONTAINING LACTOBACILLI ON GROWTH PERFORMANCE AND POPULATIONS OF BACTERIA IN THE CECA, CLOACA, AND CARCASS RINSE OF BROILER CHICKENS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to examine the effect of feeding a botanical probiotic containing Lactobacillus on growth performance of broiler chickens from 1 to 42 d of age. At 56 d, five broilers per pen were killed and processed to determine bacteria populations in the ceca, cloaca, and carcass rinse....

  15. Tigemonam, an oral monobactam.

    PubMed Central

    Chin, N X; Neu, H C

    1988-01-01

    Tigemonam is an orally administered monobactam. At less than or equal to 1 microgram/ml it inhibited the majority of strains of Escherichia coli, Klebsiella spp., Enterobacter aerogenes, Citrobacter diversus, Proteus spp., Providencia spp., Aeromonas hydrophila, Salmonella spp., Shigella spp., Serratia marcescens, and Yersinia enterocolitica. At less than or equal to 0.25 microgram/ml it inhibited Haemophilus spp., Neisseria spp., and Branhamella catarrhalis. It did not inhibit Pseudomonas spp. or Acinetobacter spp. Tigemonam was more active than cephalexin and amoxicillin-clavulanate and inhibited many members of the family Enterobacteriaceae resistant to trimethoprim-sulfamethoxazole and gentamicin. Some Enterobacter cloacae and Citrobacter freundii strains resistant to aminothiazole iminomethoxy cephalosporins and aztreonam were resistant to tigemonam. The MIC for 90% of hemolytic streptococci of groups A, B, and C and for Streptococcus pneumoniae was 16 micrograms/ml, but the MIC for 90% of enterococci, Listeria spp., Bacteroides spp., and viridans group streptococci was greater than 64 micrograms/ml. Tigemonam was not hydrolyzed by the common plasmid beta-lactamases such as TEM-1 and SHV-1 or by the chromosomal beta-lactamases of Enterobacter, Morganella, Pseudomonas, and Bacteroides spp. Tigemonam inhibited beta-lactamases of E. cloacae and Pseudomonas aeruginosa but did not induce beta-lactamases. The growth medium had a minimal effect on the in vitro activity of tigemonam, and there was a close agreement between the MICs and MBCs. PMID:3279906

  16. Fetal ascites and hydrometrocolpos due to persistent urogenital sinus and cloaca: a rare congenital anomaly and review of literature.

    PubMed

    Nigam, Aruna; Kumar, Manisha; Gulati, Shilpa

    2014-01-01

    Fetal ascites can occur due to many heterogeneous disorders. Its association with hydrometrocolpos because of persistent urogenital sinus and cloaca is extremely rare. A 29-year-old primigravida presented at 32 weeks of gestation with ultrasonographic evidence of fetal ascites, a cystic pelvic mass, hydronephrosis and oligohydramnios. Fetal ascites in this case was due to fetal urine draining through fallopian tubes into the abdomen as a result of vesicovaginal fistula and distal vaginal atresia. The antenatal ultrasound results along with autopsy findings are discussed. Though rare, a persistent urogenital sinus is to be suspected in isolated fetal ascites cases where the viral tests are negative and there is no evidence of cardiac anomalies as this is a treatable anomaly if diagnosed at early gestational age. PMID:24554677

  17. Fetal ascites and hydrometrocolpos due to persistent urogenital sinus and cloaca: a rare congenital anomaly and review of literature

    PubMed Central

    Nigam, Aruna; Kumar, Manisha; Gulati, Shilpa

    2014-01-01

    Fetal ascites can occur due to many heterogeneous disorders. Its association with hydrometrocolpos because of persistent urogenital sinus and cloaca is extremely rare. A 29-year-old primigravida presented at 32 weeks of gestation with ultrasonographic evidence of fetal ascites, a cystic pelvic mass, hydronephrosis and oligohydramnios. Fetal ascites in this case was due to fetal urine draining through fallopian tubes into the abdomen as a result of vesicovaginal fistula and distal vaginal atresia. The antenatal ultrasound results along with autopsy findings are discussed. Though rare, a persistent urogenital sinus is to be suspected in isolated fetal ascites cases where the viral tests are negative and there is no evidence of cardiac anomalies as this is a treatable anomaly if diagnosed at early gestational age. PMID:24554677

  18. Transformation of Enterobacter gergoviae isolated from pink bollworm (Lepidoptera: Gelechiidae) gut with Bacillus thuringiensis toxin.

    PubMed

    Kuzina, Lyudmila V; Miller, Ernie D; Ge, Baoxue; Miller, Thomas A

    2002-01-01

    Production of molecules with toxic activity by genetically transformed symbiotic bacteria of pest insects may serve as a powerful approach to biological control. The symbiont, Enterobacter gergoviae, isolated from the gut of the pink bollworm (PBW), has been transformed to express Cyt1A, a cytolytic protein toxin lethal to mosquito and black fly larvae, as a model system. These transgenic bacteria might be used to spread genes encoding insecticidal proteins to populations of agricultural insects or as replacement for chemical insecticides such as malathion used in bait formulation to control specific insect pests, because of extreme public pressure against organophosphate pesticide spraying. PMID:11727033

  19. Characterization of a collection of Enterobacter sakazakii isolates from environmental and food sources.

    PubMed

    Drudy, Denise; O'Rourke, Michele; Murphy, Mary; Mullane, Niall R; O'Mahony, Rebecca; Kelly, Lorraine; Fischer, Matthias; Sanjaq, Suhad; Shannon, Pauline; Wall, Patrick; O'Mahony, Micheál; Whyte, Paul; Fanning, Séamus

    2006-07-15

    Enterobacter sakazakii has emerged as a rare cause of neonatal meningitis, septicemia and enterocolitis. Contaminated infant milk formula (IMF) has been identified as one infection route. A small number of clinical outbreaks have been epidemiologically linked to IMF contaminated post-pasteurization during manufacture and/or mishandled when reconstituted. Currently no agreed standardized typing protocol has been developed to trace E. sakazakii. The objectives of this study were to apply biochemical and genetic methods to characterize 51 environmental and food E. sakazakii isolates and 6 E. sakazakii type strains. Isolates were presumptively identified using biochemical profiles based on API 20E and ID32E methods and by culture on differential selective Druggan Forsythe Iversen (DFI) agar. Identification was subsequently confirmed by real time polymerase chain reaction (PCR). All but one of the isolates was identified as E. sakazakii by biochemical profiling. One isolate was identified as Escherichia vulneris by ID 32E and as Pantoea agglomerans by API 20E. All isolates produced green/blue colonies on DFI medium characteristic of this organism. Real time PCR could differentiate between E. sakazakii, Enterobacter spp. and other Enterobacteriacae. Analysis of RAPD banding patterns revealed 3 major clusters of E. sakazakii. There was a large degree of diversity noted amongst the remaining isolates. Our findings indicate that RAPD may be applied as a useful and reliable tool for direct comparison of E. sakazakii isolates providing traceability through the infant formula food chain. PMID:16730386

  20. Evidence supporting dissimilatory and assimilatory lignin degradation in Enterobacter lignolyticus SCF1

    SciTech Connect

    DeAngelis, Kristen M.; Sharma, Deepak; Varney, Rebecca; Simmons, Blake A.; Isern, Nancy G.; Markillie, Lye Meng; Nicora, Carrie D.; Norbeck, Angela D.; Taylor, Ronald C.; Aldrich, Joshua T.; Robinson, Errol W.

    2013-08-29

    The anaerobic isolate Enterobacter lignolyticus SCF1 was initially cultivated based on anaerobic growth on lignin as sole carbon source. The source of the isolated bacteria was from tropical forest soils that decompose litter rapidly with low and fluctuating redox potentials, making it likely that bacteria using oxygen-independent enzymes play an important role in decomposition. We have examined differential expression of the anaerobic isolate Enterobacter lignolyticus SCF1 during growth on lignin. After 48 hours of growth, we used transcriptomics and proteomics to define the enzymes and other regulatory machinery that these organisms use to degrade lignin, as well as metabolomics to measure lignin degradation and monitor the use of lignin and iron as terminal electron acceptors that facilitate more efficient use of carbon. Proteomics revealed accelerated xylose uptake and metabolism under lignin-amended growth, and lignin degradation via the 4-hydroxyphenylacetate degradation pathway, catalase/peroxidase enzymes, and the glutathione biosynthesis and glutathione S-transferase proteins. We also observed increased production of NADH-quinone oxidoreductase, other electron transport chain proteins, and ATP synthase and ATP-binding cassette (ABC) transporters. Our data shows the advantages of a multi-omics approach, where incomplete pathways identified by genomics were completed, and new observations made on coping with poor carbon availability. The fast growth, high efficiency and specificity of enzymes employed in bacterial anaerobic litter deconstruction makes these soils useful templates for improving biofuel production.

  1. Growth of bacteria in enteral feeding solutions.

    PubMed

    Anderton, A

    1985-08-01

    Solutions of Clinifeed ISO, Triosorbon, Vivonex Standard (full- and half-strength) and Vivonex HN were experimentally contaminated with two strains each of Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella aerogenes, Escherichia coli and Enterobacter cloacae at concentrations of 10(2)-10(3) organisms/ml. Samples were incubated at 4, 25 or 37 degrees C and viable counts were made at 0, 4, 8 and 24 h. No increase in numbers of any of the organisms was observed in any of the feeds during 24 h at 4 degrees C. All organisms multiplied rapidly in Clinifeed ISO and in Triosorbon at 25 and 37 degrees C. There was less rapid growth in half-strength Vivonex Standard at 25 degrees C, although at 37 degrees C all strains multiplied rapidly except for the two S. aureus strains, the growth of which was inhibited in half-strength Vivonex Standard at both 25 and 37 degrees C. In full-strength Vivonex Standard at 25 degrees C, only P. aeruginosa showed any increase in numbers during 24 h, whereas P. aeruginosa, K. aerogenes and E. cloacae all multiplied at 37 degrees C. None of the test organisms multiplied in full strength Vivonex HN at any of the temperatures studied. The results of the study show that bacteria survive and may multiply even in feeds with low pH and high osmolarity, and emphasise the importance of strict hygiene during the preparation and handling of all enteral feeds. PMID:3927003

  2. Draft Genome Sequence of Endophytic Bacterium Enterobacter asburiae PDA134, Isolated from Date Palm (Phoenix dactylifera L.) Roots

    PubMed Central

    2016-01-01

    In this report, a draft of the Enterobacter asburiae strain PDA134 genome was sequenced. This bacterial strain was isolated from the root tissue of a date palm, where it has the ability to produce 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase and indole-3-acetic acid (IAA) under salinity stress. PMID:27540071

  3. Draft Genome Sequence of Endophytic Bacterium Enterobacter asburiae PDA134, Isolated from Date Palm (Phoenix dactylifera L.) Roots.

    PubMed

    Yaish, Mahmoud W

    2016-01-01

    In this report, a draft of the Enterobacter asburiae strain PDA134 genome was sequenced. This bacterial strain was isolated from the root tissue of a date palm, where it has the ability to produce 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase and indole-3-acetic acid (IAA) under salinity stress. PMID:27540071

  4. Plant growth promotion and root colonization by EPS producing Enterobacter sp. RZS5 under heavy metal contaminated soil.

    PubMed

    Sayyed, R Z; Patel, P R; Shaikh, S S

    2015-02-01

    The heavy metal resistant bacterium isolated from field soil and identified as Enterobacter sp. RZS5 tolerates a high concentration (100-2000 μM) of various heavy metal ions such as Mn2+, Ni2+, Zn2+, Cu2+, CO2+ and Fe2+ when grown in such environment and produces exopolysaccharides (EPS). Here, we have demonstrated EPS production by Enterobacter sp. RZS5 during 60 h of growth in yeast extract mannitol broth (YEMB). The yield increased by two fold after the addition of 60 μM of Ca2+; 50 μM of Fe2+ and 60 μM of Mg2+ ions in YEMB, and the optimization of physico-chemical parameters. EPS was extracted with 30% (v/v) of isopropanol as against the commonly used 50% (v/v) isopropanol method. EPS-rich broth promoted seed germination, shoot height, root length, number of leaves and chlorophyll content of wheat (Triticum aestivum) seed and peanut (Arachis hypogaea) seed. The higher colony-forming unit of Enterobacter sp. in soil inoculated with EPS rich broth of Enterobacter sp. indicated the root colonizing potential and rhizosphere competence of the isolate. The FTIR spectra of the EPS extract confirmed the presence of the functional group characteristics of EPS known to exhibit a high binding affinity towards certain metal ions. This overall growth and vigour in plants along with the effective root colonization, reflected the potential of the isolate as an efficient bio-inoculant in bioremediation. PMID:25757243

  5. Carbapenemase-producing Enterobacteriaceae in a tertiary hospital in Madrid, Spain: high percentage of colistin resistance among VIM-1-producing Klebsiella pneumoniae ST11 isolates.

    PubMed

    Pena, Irene; Picazo, Juan J; Rodríguez-Avial, Carmen; Rodríguez-Avial, Iciar

    2014-05-01

    Here we describe the carbapenemase genes, genetic relatedness and antimicrobial susceptibility data of 123 carbapenemase-producing Enterobacteriaceae (CPE) clinical isolates recovered from 2010 to 2012, comprising Klebsiella pneumoniae (n = 79), Klebsiella oxytoca (n = 13), Serratia marcescens (n = 14), Enterobacter cloacae (n = 12), Enterobacter asburiae (n = 4) and Enterobacter aerogenes (n = 1). VIM-1 was the most common carbapenemase (n = 101) followed by KPC-2 (n = 19), OXA-48 (n = 2) and IMP-22 (n = 1). Among the K. pneumoniae isolates, nine sequence types (STs) were identified but two clones were dominant: ST11 (54/79) containing mainly VIM-1-producing isolates; and ST101 (13/79) constituted by KPC-2-producing strains. Pulsed-field gel electrophoresis (PFGE) showed a higher genetic diversity among the remaining Enterobacteriaceae. Amikacin and fosfomycin were the most active agents with 82.9% and 80.5% susceptibility, respectively. Non-susceptibility to tigecycline was detected in 36.5% of strains. Overall, colistin resistance was 24.7% and was as high as 47% in Enterobacter spp. An increase in colistin resistance from 13.5% to 31.7% was observed among K. pneumoniae isolates during the study period. Resistance was focused on ST11 since 83.3% of colistin-resistant strains belonged to this clone. The high level of colistin resistance observed in this study is worrying with respect to the already limited therapeutic options for infections caused by multidrug-resistant Gram-negative bacteria. PMID:24657043

  6. Evaluation of a chromogenic medium supplemented with glucose for detecting Enterobacter sakazakii.

    PubMed

    Song, Kwang-Young; Hyeon, Ji-Yeon; Shin, Ho-Chul; Park, Chan-Kyu; Choi, In-Soo; Seo, Kun-Ho

    2008-03-01

    A commercial chromogenic agar medium (DFI) was supplemented with glucose (mDFI) to enhance the specificity of Enterobacter sakazakii (E. sakazakii) detection. Escherichia vulneris (E. vulneris), a putative false-positive strain on the DFI medium, produces alpha-glucosidase. The enzyme alpha- glucosidase hydrolyzes a substrate, 5-bromo-4-chloro-3- indolyl-alpha,D-glucopyranoside (XalphaGlc), producing green colonies. E. sakazakii strains produced green colonies on both DFI and mDFI agar, whereas E. vulneris produced green colonies on DFI agar but small white colonies on mDFI agar. E. sakazakii and E. vulneris were also readily differentiated by colony color when the mixed culture of the two strains was plated on mDFI agar and incubated for 24 h at 37 degrees C. The results indicate that the selectivity of the commercial chromogenic agar medium could be improved by a simple supplementation with glucose. PMID:18388480

  7. Association and attraction of blueberry maggot fly Curran (Diptera: Tephritidae) to Pantoea (Enterobacter) agglomerans.

    PubMed

    MacCollom, G B; Lauzon, C R; Sjogren, R E; Meyer, W L; Olday, F

    2009-02-01

    The attraction of washed, medium-free cells of Pantoea (Enterobacter) agglomerans to wild, adult Rhagoletis mendax Curran, the blueberry maggot fly, was evaluated in managed blueberry fields in Maine. Attraction was evaluated using Pherocon AM and Ladd traps, each tested with or without washed bacterial cells. Field studies showed significant increases in fly captures on the Pherocon AM traps. Apple volatiles odors on Ladd traps seemed to cancel the effects of bacterial odors. Aerobic heterotrophic bacteria were isolated and identified from alimentary organs within wild R. mendax. Isolates indentified included P. agglomerans. Blueberries collected in the field were surveyed for the presence of P. agglomerans and blueberries containing blueberry maggot larvae and noninfested blueberries were analyzed for amino acid content. Maggot-infested blueberry contained twice the amino acid nitrogen than that of noninfested blueberry. P. agglomerans, like with other pest tephritids, seems to be a cosmopolite with blueberry maggot. PMID:19791604

  8. Cloning and characterization of newly isolated lipase from Enterobacter sp. Bn12

    PubMed Central

    Farrokh, Parisa; Yakhchali, Bagher; Karkhane, Ali Asghar

    2014-01-01

    A mesophilic Enterobacter sp. Bn12 producing an alkaline thermostable lipase was isolated from soil in Tehran, Iran. The lipase gene (ELBn12) was identified from a genomic library. Sequence analysis of the DNA fragment revealed an open reading frame of 879 bp encoding a lipase with a molecular mass of 31.3 kDa. The deduced amino acid sequence showed 96% identity with a lipase of Enterobacter sp. Ag1 and the identity of their DNA sequences was 88.9%. ELBn12 belongs to the lipase subfamily I.1 and its catalytic triad consists of Ser82, Asp237 and His259. The lipase was expressed in Escherichia coli (BL21) pLysS and partially purified by anion exchange chromatography. The maximum activity of ELBn12 was obtained at temperature of 60 °C and pH 8.0 towards tricaprylin (C8) and its specific activity was around 2900 U/mg. ELBn12 was stable within a broad pH range from 6.0 to 11.0. The enzyme showed high stability in both polar and nonpolar organic solvents at 50% (v/v). The lipase activity was enhanced in the presence of 10 mM of Ca2+, Mg2+ and K+, while heavy metals (Fe3+ and Zn2+) had strong inhibitory effect. ELBn12 showed high activity in the presence of 1% (w/v) nonionic surfactants, however ionic surfactants inhibited the lipolytic activity. ELBn12 characteristics show that it has a potential to be used in various industrial processes. PMID:25242958

  9. Isolation and characterization of diverse antimicrobial lipopeptides produced by Citrobacter and Enterobacter

    PubMed Central

    2013-01-01

    Background Increasing multidrug-resistance in bacteria resulted in a greater need to find alternative antimicrobial substances that can be used for clinical applications or preservation of food and dairy products. Research on antimicrobial peptides including lipopeptides exhibiting both narrow and broad spectrum inhibition activities is increasing in the recent past. Therefore, the present study was aimed at isolation and characterization of antimicrobial lipopeptide producing bacterial strains from fecal contaminated soil sample. Results The phenotypic and 16S rRNA gene sequence analysis of all isolates identified them as different species of Gram-negative genera Citrobacter and Enterobacter. They exhibited common phenotypic traits like citrate utilization, oxidase negative and facultative anaerobic growth. The HPLC analysis of solvent extracts obtained from cell free fermented broth revealed the presence of multiple antimicrobial lipopeptides. The comprehensive mass spectral analysis (MALDI-TOF MS and GC-MS) of HPLC purified fractions of different isolates revealed that the lipopeptides varied in their molecular weight between (m/z) 607.21 to 1536.16 Da. Isomers of mass ion m/z 984/985 Da was produced by all strains. The 1495 Da lipopeptides produced by strains S-3 and S-11 were fengycin analogues and most active against all strains. While amino acid analysis of lipopeptides suggested most of them had similar composition as in iturins, fengycins, kurstakins and surfactins, differences in their β-hydroxy fatty acid content proposed them to be isoforms of these lipopeptides. Conclusion Although antimicrobial producing strains can be used as biocontrol agents in food preservation, strains with ability to produce multiple antimicrobial lipopeptides have potential applications in biotechnology sectors such as pharmaceutical and cosmetic industry. This is the first report on antibacterial lipopeptides production by strains of Citrobacter and Enterobacter. PMID

  10. Cloning and characterization of newly isolated lipase from Enterobacter sp. Bn12.

    PubMed

    Farrokh, Parisa; Yakhchali, Bagher; Karkhane, Ali Asghar

    2014-01-01

    A mesophilic Enterobacter sp. Bn12 producing an alkaline thermostable lipase was isolated from soil in Tehran, Iran. The lipase gene (ELBn12) was identified from a genomic library. Sequence analysis of the DNA fragment revealed an open reading frame of 879 bp encoding a lipase with a molecular mass of 31.3 kDa. The deduced amino acid sequence showed 96% identity with a lipase of Enterobacter sp. Ag1 and the identity of their DNA sequences was 88.9%. ELBn12 belongs to the lipase subfamily I.1 and its catalytic triad consists of Ser82, Asp237 and His259. The lipase was expressed in Escherichia coli (BL21) pLysS and partially purified by anion exchange chromatography. The maximum activity of ELBn12 was obtained at temperature of 60 °C and pH 8.0 towards tricaprylin (C8) and its specific activity was around 2900 U/mg. ELBn12 was stable within a broad pH range from 6.0 to 11.0. The enzyme showed high stability in both polar and nonpolar organic solvents at 50% (v/v). The lipase activity was enhanced in the presence of 10 mM of Ca(2+), Mg(2+) and K(+), while heavy metals (Fe(3+) and Zn(2+)) had strong inhibitory effect. ELBn12 showed high activity in the presence of 1% (w/v) nonionic surfactants, however ionic surfactants inhibited the lipolytic activity. ELBn12 characteristics show that it has a potential to be used in various industrial processes. PMID:25242958

  11. Enterobacter sacchari sp. nov., a nitrogen-fixing bacterium associated with sugar cane (Saccharum officinarum L.).

    PubMed

    Zhu, Bo; Zhou, Qing; Lin, Li; Hu, Chunjin; Shen, Ping; Yang, Litao; An, Qianli; Xie, Guanlin; Li, Yangrui

    2013-07-01

    Five nitrogen-fixing bacterial strains (SP1(T), NN143, NN144, NN208 and HX148) were isolated from stem, root or rhizosphere soil of sugar cane (Saccharum officinarum L.) plants. Cells were Gram-negative, motile, rods with peritrichous flagella. DNA G+C content was 55.0 ± 0.5 mol%. Sequence determinations and phylogenetic analysis of 16S rRNA gene and rpoB indicated that the strains were affiliated with the genus Enterobacter and most closely related to E. radicincitans DSM 16656(T) and E. oryzae LMG 24251(T). Fluorimetric determination of thermal denaturation temperatures after DNA-DNA hybridization, enterobacterial repetitive intergenic consensus PCR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry differentiated the whole-genome, genotype and protein profiles from those of E. radicincitans and E. oryzae. The strains' cell fatty acid composition differentiated them from E. radicincitans and E. oryzae by containing a higher level of summed feature 2 (C16 : 1ω7c and/or C16 : 1ω6c) and a lower level of C17 : 0 cyclo. Their physiological and biochemical profiles differentiated them from E. radicincitans by being positive for methyl red test, ornithine decarboxylase and utilization of putrescine, D-arabitol, L-fucose and methyl α-D-glucoside and being negative for arginine dihydrolase, and differentiated them from E. oryzae by being positive for aesculin hydrolysis and utilization of putrescine, D-arabitol and L-rhamnose and being negative for arginine dihydrolase, lysine decarboxylase and utilization of mucate. The five strains therefore represent a novel species, for which the name Enterobacter sacchari sp. nov. is proposed, with the type strain SP1(T) ( = CGMCC 1.12102(T) = LMG 26783(T)). PMID:23291881

  12. Complete Genome Sequence of Enterobacter sp. Strain R4-368, an Endophytic N-Fixing Gammaproteobacterium Isolated from Surface-Sterilized Roots of Jatropha curcas L.

    PubMed

    Madhaiyan, Munusamy; Peng, Ni; Ji, Lianghui

    2013-01-01

    Enterobacter sp. strain R4-368 is one of the few characterized Jatropha endophytic diazotrophic bacteria and was isolated from surface-sterilized roots. This bacterium shows strong growth-promoting effects, being able to increase plant biomass and seed yields. Enterobacter sp. R4-368 is the second fully sequenced diazotrophic Enterobacter species. The sequence information shall facilitate the elucidation of the molecular mechanisms of plant growth promotion, nitrogen fixation in nonlegume plant species, and evolution of biological nitrogen fixation systems. PMID:23908287

  13. The combination Enterobacter agglomerans is to be cited as Enterobacter agglomerans (Beijerinck 1888) Ewing and Fife 1972 and the combination Pantoea agglomerans is to be cited as Pantoea agglomerans (Beijerinck 1888) Gavini et al. 1989. Opinion 90. Judicial Commission of the International Committee on Systematics of Prokaryotes.

    PubMed

    Tindall, B J

    2014-10-01

    The Judicial Commission affirms that, according to information presented to it, the combination Enterobacter agglomerans is to be cited as Enterobacter agglomerans (Beijerinck 1888) Ewing and Fife 1972 and the combination Pantoea agglomerans is to be cited as Pantoea agglomerans (Beijerinck 1888) Gavini et al. 1989. PMID:25288660

  14. Analysis of a Soluble (UreD:UreF:UreG)2 Accessory Protein Complex and Its Interactions with Klebsiella aerogenes Urease by Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Farrugia, Mark A.; Han, Linjie; Zhong, Yueyang; Boer, Jodi L.; Ruotolo, Brandon T.; Hausinger, Robert P.

    2013-09-01

    Maturation of the nickel-containing urease of Klebsiella aerogenes is facilitated by the UreD, UreF, and UreG accessory proteins along with the UreE metallo-chaperone. A fusion of the maltose binding protein and UreD (MBP-UreD) was co-isolated with UreF and UreG in a soluble complex possessing a (MBP-UreD:UreF:UreG)2 quaternary structure. Within this complex a UreF:UreF interaction was identified by chemical cross-linking of the amino termini of its two UreF protomers, as shown by mass spectrometry of tryptic peptides. A pre-activation complex was formed by the interaction of (MBP-UreD:UreF:UreG)2 and urease. Mass spectrometry of intact protein species revealed a pathway for synthesis of the urease pre-activation complex in which individual hetero-trimer units of the (MBP-UreD:UreF:UreG)2 complex bind to urease. Together, these data provide important new insights into the structures of protein complexes associated with urease activation.

  15. [Susceptibilities of clinical bacterial isolates to antimicrobial agents. A study mainly focused on imipenem. Reported by the Research Group for Testing Imipenem Susceptibility on Clinical Isolates].

    PubMed

    Igari, J

    1990-11-01

    This study was conducted to investigate susceptibilities of clinical bacterial isolates to imipenem (IPM) and other antibacterial agents at 64 hospital laboratories throughout Japan from September to December of 1988. In this study, identification and susceptibility testing were carried out at each laboratory and the tests were performed according to the disk dilution method recommended by NCCLS in which susceptibilities are classified into "S", "MS", "I" and "R". IPM showed markedly high in vitro activities against Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus agalactiae, Enterococcus faecalis, Haemophilus influenzae, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Enterobacter cloacae, Serratia marcescens, Salmonella spp., Citrobacter freundii, Proteus mirabilis, Proteus vulgaris, Morganella morganii, Providencia rettgeri, Providencia stuartii, Acinetobacter calcoaceticus, Moraxella (Branhamella) catarrhalis, Alcaligenes spp., Peptococcus spp./Peptostreptococcus spp., Bacteroides fragilis and Bacteroides spp. IPM also had strong activities against Achromobacter xylosoxidans and Pseudomonas aeruginosa, but less active against Flavobacterium spp., E. faecium, coagulase-negative staphylococci (CNS), Staphylococcus aureus and Pseudomonas cepacia. In a study in which activities of IPM against bacteria isolated from different clinical sources were compared, differences in susceptibilities were observed among S. aureus, CNS, A. calcoaceticus and P. aeruginosa, but such differences were not apparent among S. pneumoniae, E. faecalis, H. influenzae, E. coli, K. pneumoniae, E. cloacae, C. freundii, S. marcescens or P. mirabilis. PMID:2287060

  16. [Susceptibilities of clinical bacterial isolates to antimicrobial agents. A study mainly focused on imipenem. Research Group for Testing Imipenem Susceptibility on Clinical Isolates].

    PubMed

    Igari, J

    1990-10-01

    We investigated susceptibilities of clinical bacterial isolates to imipenem (IPM) and other antimicrobial agents at 459 hospital laboratories throughout Japan from September to December of 1988. In this study, identification and susceptibility testing were performed at each hospital laboratory and the tests were carried out according to the 1-dilution or 3-dilution disc technique in which susceptibilities are classified into 4 grades: , ++, + and -. IPM had significantly high activity against Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus agalactiae, Neisseria gonorrhoeae, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Enterobacter cloacae, Salmonella spp., Citrobacter freundii, Proteus mirabilis, Providencia rettgeri, Acinetobacter calcoaceticus, Moraxella catarrhalis, Alcaligenes spp., Peptococcus spp./Peptostreptococcus spp., Bacteroides fragilis and Bacteroides spp. and should slightly lower activities on coagulase-negative staphylococci (CNS), Enterococcus faecalis, Haemophilus influenzae, Serratia marcescens, Proteus vulgaris, Providencia stuartii and Pseudomonas aeruginosa than on the above mentioned bacteria. In a comparative study on activities of IPM against bacteria from different clinical sources, no remarkable differences were found due to different sources among S. pneumoniae, E. faecalis, H. influenzae, E. coli, K. pneumoniae, E. cloacae, C. freundii, P. mirabilis or A. calcoaceticus, whereas slight differences were found among Staphylococcus aureus, CNS, S. marcescens and P. aeruginosa. PMID:2086814

  17. High-quality draft genome sequence of Enterobacter sp. Bisph2, a glyphosate-degrading bacterium isolated from a sandy soil of Biskra, Algeria

    PubMed Central

    Benslama, Ouided; Boulahrouf, Abderrahmane

    2016-01-01

    Enterobacter sp. strain Bisph2 was isolated from a sandy soil from Biskra, Algeria and exhibits glyphosate-degrading activity. Multilocus sequence analysis of the 16S rRNA, rpoB, hsp60, gyrB and dnaJ genes demonstrated that Bisph2 might be a member of a new species of the genus Enterobacter. Genomic sequencing of Bisph2 was used to better clarify the relationships among Enterobacter species. Annotation and analysis of the genome sequence showed that the 5.535.656 bp genome of Enterobacter sp. Bisph2 consists in one chromosome and no detectable plasmid, has a 53.19% GC content and 78% of genes were assigned a putative function. The genome contains four prophages of which 3 regions are intact and no CRISPER was detected. The nucleotide sequence of this genome was deposited into DDBJ/EMBL/GenBank under the accession JXAF00000000. PMID:27222800

  18. High-quality draft genome sequence of Enterobacter sp. Bisph2, a glyphosate-degrading bacterium isolated from a sandy soil of Biskra, Algeria.

    PubMed

    Benslama, Ouided; Boulahrouf, Abderrahmane

    2016-06-01

    Enterobacter sp. strain Bisph2 was isolated from a sandy soil from Biskra, Algeria and exhibits glyphosate-degrading activity. Multilocus sequence analysis of the 16S rRNA, rpoB, hsp60, gyrB and dnaJ genes demonstrated that Bisph2 might be a member of a new species of the genus Enterobacter. Genomic sequencing of Bisph2 was used to better clarify the relationships among Enterobacter species. Annotation and analysis of the genome sequence showed that the 5.535.656 bp genome of Enterobacter sp. Bisph2 consists in one chromosome and no detectable plasmid, has a 53.19% GC content and 78% of genes were assigned a putative function. The genome contains four prophages of which 3 regions are intact and no CRISPER was detected. The nucleotide sequence of this genome was deposited into DDBJ/EMBL/GenBank under the accession JXAF00000000. PMID:27222800

  19. My 40-Year History with Cronobacter/Enterobacter sakazakii – Lessons Learned, Myths Debunked, and Recommendations

    PubMed Central

    Farmer, John J.

    2015-01-01

    Much has been learned about organism in the Cronobacter/Enterobacter sakazakii complex since I first named and described Enterobacter sakazakii in 1980. However, there are still wide knowledge gaps. One of the most serious is that are still many uncertainties associated with assessing the public health risk posed by these bacteria, particularly in neonatal meningitis. Over the last few decades, Cronobacter contamination of commercial powdered infant formula products has apparently been reduced, but it is still an ongoing problem. The powdered infant formula industry still cannot produce powdered formula that is free of bacterial contamination with Cronobacter, other Enterobacteriaceae, other pathogenic bacteria, and other microorganisms. Until this happens, infants and other will be at risk of becoming infected when they ingest contaminated formula. PMID:26640778

  20. Transcriptional Responses to Sucrose Mimic the Plant-Associated Life Style of the Plant Growth Promoting Endophyte Enterobacter sp. 638

    SciTech Connect

    Taghavi, Safiyh; Wu, Xiao; Ouyang, Liming; Zhang, Yian Biao; Stadler, Andrea; McCorkle, Sean; Zhu, Wei; Maslov, Sergei; van der Lelie, Daniel

    2015-01-21

    Growth in sucrose medium was previously found to trigger the expression of functions involved in the plant associated life style of the endophytic bacterium Enterobacter sp. 638. Therefore, comparative transcriptome analysis between cultures grown in sucrose or lactate medium was used to gain insights in the expression levels of bacterial functions involved in the endophytic life style of strain 638. Growth on sucrose as a carbon source resulted in major changes in cell physiology, including a shift from a planktonic life style to the formation of bacterial aggregates. This shift was accompanied by a decrease in transcription of genes involved in motility (e.g. flagella biosynthesis) and an increase in the transcription of genes involved in colonization, adhesion and biofilm formation. The transcription levels of functions previously suggested as being involved in endophytic behavior and functions responsible for plant growth promoting properties, including the synthesis of indole-acetic acid, acetoin and 2,3-butanediol, also increased significantly for cultures grown in sucrose medium. Interestingly, despite an abundance of essential nutrients transcription levels of functions related to uptake and processing of nitrogen and iron became increased for cultures grown on sucrose as sole carbon source. Transcriptome data were also used to analyze putative regulatory relationships. In addition to the small RNA csrABCD regulon, which seems to play a role in the physiological adaptation and possibly the shift between free-living and plant-associated endophytic life style of Enterobacter sp. 638, our results also pointed to the involvement of rcsAB in controlling responses by Enterobacter sp. 638 to a plant-associated life style. Lastly, targeted mutagenesis was used to confirm this role and showed that compared to wild-type Enterobacter sp. 638 a ΔrcsB mutant was affected in its plant growth promoting ability.

  1. Transcriptional Responses to Sucrose Mimic the Plant-Associated Life Style of the Plant Growth Promoting Endophyte Enterobacter sp. 638

    DOE PAGESBeta

    Taghavi, Safiyh; Wu, Xiao; Ouyang, Liming; Zhang, Yian Biao; Stadler, Andrea; McCorkle, Sean; Zhu, Wei; Maslov, Sergei; van der Lelie, Daniel

    2015-01-21

    Growth in sucrose medium was previously found to trigger the expression of functions involved in the plant associated life style of the endophytic bacterium Enterobacter sp. 638. Therefore, comparative transcriptome analysis between cultures grown in sucrose or lactate medium was used to gain insights in the expression levels of bacterial functions involved in the endophytic life style of strain 638. Growth on sucrose as a carbon source resulted in major changes in cell physiology, including a shift from a planktonic life style to the formation of bacterial aggregates. This shift was accompanied by a decrease in transcription of genes involvedmore » in motility (e.g. flagella biosynthesis) and an increase in the transcription of genes involved in colonization, adhesion and biofilm formation. The transcription levels of functions previously suggested as being involved in endophytic behavior and functions responsible for plant growth promoting properties, including the synthesis of indole-acetic acid, acetoin and 2,3-butanediol, also increased significantly for cultures grown in sucrose medium. Interestingly, despite an abundance of essential nutrients transcription levels of functions related to uptake and processing of nitrogen and iron became increased for cultures grown on sucrose as sole carbon source. Transcriptome data were also used to analyze putative regulatory relationships. In addition to the small RNA csrABCD regulon, which seems to play a role in the physiological adaptation and possibly the shift between free-living and plant-associated endophytic life style of Enterobacter sp. 638, our results also pointed to the involvement of rcsAB in controlling responses by Enterobacter sp. 638 to a plant-associated life style. Lastly, targeted mutagenesis was used to confirm this role and showed that compared to wild-type Enterobacter sp. 638 a ΔrcsB mutant was affected in its plant growth promoting ability.« less

  2. Transcriptional Responses to Sucrose Mimic the Plant-Associated Life Style of the Plant Growth Promoting Endophyte Enterobacter sp. 638

    PubMed Central

    Taghavi, Safiyh; Wu, Xiao; Ouyang, Liming; Stadler, Andrea; McCorkle, Sean; Zhu, Wei; Maslov, Sergei; van der Lelie, Daniel

    2015-01-01

    Growth in sucrose medium was previously found to trigger the expression of functions involved in the plant associated life style of the endophytic bacterium Enterobacter sp. 638. Therefore, comparative transcriptome analysis between cultures grown in sucrose or lactate medium was used to gain insights in the expression levels of bacterial functions involved in the endophytic life style of strain 638. Growth on sucrose as a carbon source resulted in major changes in cell physiology, including a shift from a planktonic life style to the formation of bacterial aggregates. This shift was accompanied by a decrease in transcription of genes involved in motility (e.g. flagella biosynthesis) and an increase in the transcription of genes involved in colonization, adhesion and biofilm formation. The transcription levels of functions previously suggested as being involved in endophytic behavior and functions responsible for plant growth promoting properties, including the synthesis of indole-acetic acid, acetoin and 2,3-butanediol, also increased significantly for cultures grown in sucrose medium. Interestingly, despite an abundance of essential nutrients transcription levels of functions related to uptake and processing of nitrogen and iron became increased for cultures grown on sucrose as sole carbon source. Transcriptome data were also used to analyze putative regulatory relationships. In addition to the small RNA csrABCD regulon, which seems to play a role in the physiological adaptation and possibly the shift between free-living and plant-associated endophytic life style of Enterobacter sp. 638, our results also pointed to the involvement of rcsAB in controlling responses by Enterobacter sp. 638 to a plant-associated life style. Targeted mutagenesis was used to confirm this role and showed that compared to wild-type Enterobacter sp. 638 a ΔrcsB mutant was affected in its plant growth promoting ability. PMID:25607953

  3. [Epidemiologic study on the prevalence of Enterobacter, Serratia and Pseudomonas strains, producers of cefoxitin-inducible beta-lactamases].

    PubMed

    Marone, P; Concia, E; Perversi, L; Cruciani, M

    1986-01-01

    Resistance of Enterobacter, Serratia and pseudomonas strains to newer cephalosporins is often associated with stable derepression of synthesis of the chromosomal betalactamases. Similar resistance is developed by enzyme inducible strains in response to betalactamases inducers. This finding poses many clinical problems including emergence of resistance during therapy with the drugs. In this study we evaluated the MICs of several new betalactam compounds against 76 Enterobacter, Serratia and Pseudomonas strains before and after cefoxitin-induction of betalactamases. The MICs against several Enterobacter strains (45%) after cefoxitin induction were elevated four fold or more. Serratia strains showed no significant variations of the MICs after cefoxitin induction. The MICs of piperacillin against many Pseudomonas strains (78%) after cefoxitin induction were elevated four fold or more. These data were confirmed using cefoxitin disk approximation test. Outbreaks of nosocominal infection with these multiresistant bacteria and spread of the strains throughout the hospital are already being seen. Control of these problems can only be achieved through the judicious and restricted use of these new antibiotics. PMID:3103651

  4. Mutational and Computational Evidence That a Nickel-Transfer Tunnel in UreD Is Used for Activation of Klebsiella aerogenes Urease.

    PubMed

    Farrugia, Mark A; Wang, Beibei; Feig, Michael; Hausinger, Robert P

    2015-10-20

    Nickel-containing urease from Klebsiella aerogenes requires four accessory proteins for proper active site metalation. The metallochaperone UreE delivers nickel to UreG, a GTPase that forms a UreD/UreF/UreG complex, which binds to urease apoprotein via UreD. Prior in silico analysis of the homologous, structurally characterized UreH/UreF/UreG complex from Helicobacter pylori identified a water tunnel originating at a likely nickel-binding motif in UreG, passing through UreF, and exiting UreH, suggestive of a role for the channel in providing the metal to urease apoprotein for its activation; however, no experimental support was reported for the significance of this tunnel. Here, specific variants were designed to disrupt a comparable 34.6 Å predicted internal tunnel, alternative channels, and surface sites for UreD. Cells producing a set of tunnel-disrupting variants of UreD exhibited greatly reduced urease specific activities, whereas other mutants had no appreciable effect on activity. Affinity pull-down studies of cell-free extracts from tunnel-disrupting mutant cultures showed no loss of UreD interactions with urease or UreF/UreG. The nickel contents of urease samples enriched from activity-deficient cultures were decreased, while zinc and iron incorporation increased. Molecular dynamics simulations revealed size restrictions in the internal channels of the UreD variants. These findings support the role of a molecular tunnel in UreD as a direct facilitator of nickel transfer into urease, illustrating a new paradigm in active site metallocenter assembly. PMID:26401965

  5. Oxidation of d-Malic and β-Alkylmalic Acids by Wild-Type and Mutant Strains of Salmonella typhimurium and by Aerobacter aerogenes

    PubMed Central

    Stern, Joseph R.; O'Brien, R. W.

    1969-01-01

    A mutant strain of Salmonella typhimurium (SL 1634 dml-51) capable of growth on d-malate as sole carbon source was shown to produce d-malic enzyme. This enzyme was absent in the parent wild-type strain which was unable to grow on d-malate. Growth of the mutant on d-malate also resulted in a greatly increased level of β-isopropylmalic enzyme compared with its level in the wild-type strain grown on citrate or l-malate. The d-malic and β-isopropylmalic enzymes, both of which catalyze a nicotinamide adenine dinucleotide- and Mg++-dependent oxidative decarboxylation of their respective substrates, were shown to be distinct enzymes by selective inhibition with erythro-dl-β-hydroxyaspartate and by other methods. Cell extracts of the mutant strain also oxidized dl-β-methyl-, dl-β-ethyl-, dl-β-propyl- and dl-ββ-dimethylmalates, in order of decreasing activity. dl-β-Methyl-malate was shown to be oxidized by both the d-malic and the β-isopropylmalic enzymes, whereas the oxidation of the other β-alkylmalates appeared to be effected exclusively by the β-isopropylmalic enzyme. β-Isopropylmalic enzyme activity was induced by d-malate but not by l-malate, showing that it behaved as a d-malictype enzyme. Growth of Aerobacter aerogenes on d-malate, which caused induction of d malic enzyme, resulted in only a small increase in the activity of β-isopropylmalic enzyme. PMID:4889267

  6. [Yearly changes in antibacterial activities of cefozopran against various clinical isolates between 1996 and 2001--II. Gram-negative bacteria].

    PubMed

    Suzuki, Yumiko; Nishinari, Chisato; Endo, Harumi; Hiramatsu, Nobuyoshi; Akiyama, Kazumitsu; Koyama, Tsuneo

    2003-08-01

    The in vitro antibacterial activities of cefozopran (CZOP), an agent of cephems, against various clinical isolates obtained between 1996 and 2001 were yearly evaluated and compared with those of other cephems, oxacephems and carbapenems. A total of 3,245 strains in 32 species of Gram-negative bacteria were isolated from the clinical materials annually collected from January to December, and consisted of Moraxella subgenus Branhamella catarrhalis, Escherichia coli, Citrobacter freundii, Citrobacter koseri, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Enterobacter cloacae, Serratia marcescens, Proteus mirabillis, Proteus vulgaris, Morganella morganii, Providencia spp. (P. alcalifaciens, P. rettgeri, P. stuartii), Pseudomonas aeruginosa, Pseudomonas putida, Burkholderia cepacia, Stenotrophomonas maltophilia, Haemophilus influenzae, Acinetobactor baumannii, Acinetobactor lwoffii, Bacteroides fragilis group (B. fragilis, B. vulgatus, B. distasonis, B. ovatus, B. thetaiotaomicron), and Prevotella spp. (P. melaninogenica, P. intermedia, P. bivia, P. oralis, P. denticola). CZOP possessed stable antibacterial activities against M. (B.) catarrhalis, E. coli, C. freundii, C. koseri, K. pneumoniae, K. oxytoca, E. aerogenes, E. cloacae, S. marcescens, P. mirabilis, P. vulgaris, M. morganii, Providencia spp., P. aeruginosa, and A. lwoffii throughout 6 years. The MIC90 of CZOP against those strains were consistent with those obtained from the studies performed until the new drug application approval. On the other hand, the MIC90 of CZOP against H. influenzae yearly obviously increased with approximately 64-time difference during the study period. The MIC90 of cefpirome, cefepime, and flomoxef against H. influenzae also yearly tended to rise. The present results demonstrated that CZOP had maintained the antibacterial activity against almost Gram-negative strains tested. However, the decrease in antibacterial activities of CZOP against B. cepacia, and H

  7. Decolorization of azo dyes with Enterobacter agglomerans immobilized in different supports by using fluidized bed bioreactor.

    PubMed

    Moutaouakkil, Adnane; Zeroual, Youssef; Dzayri, Fatima Zohra; Talbi, Mohamed; Lee, Kangmin; Blaghen, Mohamed

    2004-02-01

    Immobilized cells of Enterobacter agglomerans, able to reduce azo dyes enzymatically, were used as a biocatalyst for the decolorization of synthetic medium containing the toxic azo dye methyl red (MR). This bacterial strain exhibits high ability to completely decolorize 100 mg/L of MR after only 6 h of incubation under aerobic conditions. Cells of E. agglomerans were immobilized in calcium alginate, polyacylamide, cooper beech, and vermiculite, and were used for the decolorization of MR from synthetic water by using a fluidized bed bioreactor. The highest specific decolorization rate was obtained when E. agglomerans was entrapped in calcium alginate beads and was of about 3.04 mg MR/g cell/h with a 50% conversion time ( t(1/2)) of about 1.6 h. Moreover, immobilized cells in calcium alginate continuously decolorized MR even after seven repeated experiments without significant loss of activity, while polyacrylamide-, cooper beech-, and vermiculite-immobilized cells retained only 62, 15, and 13% of their original activity, respectively. PMID:15057480

  8. Molecular cloning, structural analysis, and expression in Escherichia coli of a chitinase gene from Enterobacter agglomerans.

    PubMed Central

    Chernin, L S; De la Fuente, L; Sobolev, V; Haran, S; Vorgias, C E; Oppenheim, A B; Chet, I

    1997-01-01

    The gene chiA, which codes for endochitinase, was cloned from a soilborne Enterobacter agglomerans. Its complete sequence was determined, and the deduced amino acid sequence of the enzyme designated Chia_Entag yielded an open reading frame coding for 562 amino acids of a 61-kDa precursor protein with a putative leader peptide at its N terminus. The nucleotide and polypeptide sequences of Chia_Entag showed 86.8 and 87.7% identity with the corresponding gene and enzyme, Chia_Serma, of Serratia marcescens, respectively. Homology modeling of Chia_Entag's three-dimensional structure demonstrated that most amino acid substitutions are at solvent-accessible sites. Escherichia coli JM109 carrying the E. agglomerans chiA gene produced and secreted Chia_Entag. The antifungal activity of the secreted endochitinase was demonstrated in vitro by inhibition of Fusarium oxysporum spore germination. The transformed strain inhibited Rhizoctonia solani growth on plates and the root rot disease caused by this fungus in cotton seedlings under greenhouse conditions. PMID:9055404

  9. Genome sequence of Enterobacter sp. ST3, a quorum sensing bacterium associated with marine dinoflagellate

    PubMed Central

    Zhou, Jin; Lao, Yong-Min; Ma, Zhi-Ping; Cai, Zhong-Hua

    2016-01-01

    Phycosphere environment is a typical marine niche, harbor diverse populations of microorganisms, which are thought to play a critical role in algae host and influence mutualistic and competitive interactions. Understanding quorum sensing-based acyl-homoserine lactone (AHL) language may shed light on the interaction between algal-associated microbial communities in the native environment. In this work, we isolated an epidermal bacterium (was tentatively named Enterobacter sp. ST3, and deposited in SOA China, the number is MCCC1K02277-ST3) from the marine dinoflagellate Scrippsiella trochoidea, and found it has the ability to produce short-chain AHL signal. In order to better understand its communication information at molecular level, the genomic map was investigated. The genome size was determined to be 4.81 Mb with a G + C content of 55.59%, comprising 6 scaffolds of 75 contigs containing 4647 protein-coding genes. The functional proteins were predicted, and 3534 proteins were assigned to COG functional categories. An AHL-relating gene, LuxR, was found in upstream position at contig 1. This genome data may provide clues to increase understanding of the chemical characterization and ecological behavior of strain ST3 in the phycosphere microenvironment. PMID:26981407

  10. Decreasing Enterobacter sakazakii (Cronobacter spp.) food contamination level with bacteriophages: prospects and problems

    PubMed Central

    Zuber, Sophie; Boissin‐Delaporte, Catherine; Michot, Lise; Iversen, Carol; Diep, Benjamin; Brüssow, Harald; Breeuwer, Pieter

    2008-01-01

    Summary Enterobacter sakazakii (Cronobacter spp.) is an opportunistic pathogen, which can cause rare, but life‐threatening infections in neonates and infants through feeding of a contaminated milk formula. We isolated 67 phages from environmental samples and tested their lytic host range on a representative collection of 40 E. sakazakii strains. A cocktail of five phages prevented the outgrowth of 35 out of 40 test strains in artificially contaminated infant formula. Two E. sakazakii phages represented prolate head Myoviridae. Molecular tests identified them as close relatives of Escherichia coli phage T4. The remaining three phages represented isometric head Myoviridae with large genome size of 140 and 200 kb, respectively, which belonged to two different DNA hybridization groups. A high dose of 108 pfu ml−1 of phage could effectively sterilize a broth contaminated with both high and low pathogen counts (106 and 102 cfu ml−1). In contrast, broth inoculated with 104 phage and 102 bacteria per ml first showed normal bacterial growth until reaching a cell titre of 105 cfu ml−1. Only when crossing this threshold, phage replication started, but it could not reduce the contamination level below 100 cfu ml−1. Phages could be produced with titres of 1010 pfu ml−1 in broth culture, but they were not stable upon freeze‐drying. Addition of trehalose or milk formula stabilized the phage preparation, which then showed excellent storage stability even at elevated temperature. PMID:21261874

  11. Production, characteristics and applications of phytase from a rhizosphere isolated Enterobacter sp. ACSS.

    PubMed

    Chanderman, Ashira; Puri, Adarsh Kumar; Permaul, Kugen; Singh, Suren

    2016-10-01

    Optimization of process parameters for phytase production by Enterobacter sp. ACSS led to a 4.6-fold improvement in submerged fermentation, which was enhanced further in fed-batch fermentation. The purified 62 kDa monomeric phytase was optimally active at pH 2.5 and 60 °C and retained activity over a wide range of temperature (40-80 °C) and pH (2.0-6.0) with a half-life of 11.3 min at 80 °C. The kinetic parameters K m, V max, K cat, and K cat/K m of the pure phytase were 0.21 mM, 131.58 nmol mg(-1) s(-1), 1.64 × 10(3) s(-1), and 7.81 × 10(6) M(-1) s(-1), respectively. The enzyme was fairly stable in the presence of pepsin under physiological conditions. It was stimulated by Ca(+2), Mg(+2) and Mn(+2), but inhibited by Zn(+2), Cu(+2), Fe(+2), Pb(+2), Ba(+2) and surfactants. The enzyme can be applied in dephytinizing animal feeds, and the baking industry. PMID:27250653

  12. Anaerobic pathways of glycerol dissimilation by Enterobacter agglomerans CNCM 1210: limitations and regulations.

    PubMed

    Barbirato, F; Astruc, S; Soucaille, P; Camarasa, C; Salmon, J M; Bories, A

    1997-07-01

    Continuous cultures of Enterobacter agglomerans CNCM 1210 were performed under regulated pH conditions (pH 7.0) with glycerol or glucose (20 g l-1) as carbon source. Cultures grown on glucose produced mainly acetate, ethanol and formate. In contrast, 1,3-propanediol (PPD) was the main product with glycerol. The carbon flow distribution at branching metabolic points was investigated. Higher PPD yields with increased dilution rate were correlated with an important increase in the relative ratio of glycerol dehydratase to glycerol dehydrogenase. Determination of intracellular triose-phosphate and fructose 1,6-biphosphate concentrations demonstrated that glyceraldehyde-3-phosphate dehydrogenase is the limiting step in glycerol dissimilation. At the pyruvate branching point, pyruvate dehydrogenase (PDH) activity was systematically detected. The pyruvate flow shifted to PDH is suspected to represent up to 22% of the acetyl-CoA formed. In addition, this enzyme pattern combined with the enhanced in vivo lactate dehydrogenase activity at high growth rates, was correlated with a decrease in the pyruvate formate-lyase activity. A regulation of this latter enzyme by the accumulation of triose-phosphate is suspected. PMID:9245823

  13. Global transcriptome response to ionic liquid by a tropical rain forest soil bacterium, Enterobacter lignolyticus.

    PubMed

    Khudyakov, Jane I; D'haeseleer, Patrik; Borglin, Sharon E; Deangelis, Kristen M; Woo, Hannah; Lindquist, Erika A; Hazen, Terry C; Simmons, Blake A; Thelen, Michael P

    2012-08-01

    To process plant-based renewable biofuels, pretreatment of plant feedstock with ionic liquids has significant advantages over current methods for deconstruction of lignocellulosic feedstocks. However, ionic liquids are often toxic to the microorganisms used subsequently for biomass saccharification and fermentation. We previously isolated Enterobacter lignolyticus strain SCF1, a lignocellulolytic bacterium from tropical rain forest soil, and report here that it can grow in the presence of 0.5 M 1-ethyl-3-methylimidazolium chloride, a commonly used ionic liquid. We investigated molecular mechanisms of SCF1 ionic liquid tolerance using a combination of phenotypic growth assays, phospholipid fatty acid analysis, and RNA sequencing technologies. Potential modes of resistance to 1-ethyl-3-methylimidazolium chloride include an increase in cyclopropane fatty acids in the cell membrane, scavenging of compatible solutes, up-regulation of osmoprotectant transporters and drug efflux pumps, and down-regulation of membrane porins. These findings represent an important first step in understanding mechanisms of ionic liquid resistance in bacteria and provide a basis for engineering microbial tolerance. PMID:22586090

  14. Reduction of molybdate to molybdenum blue by Enterobacter sp. strain Dr.Y13.

    PubMed

    Shukor, M Y; Rahman, M F; Shamaan, N A; Syed, M A

    2009-09-01

    Extensive use of metals in various industrial applications has caused substantial environmental pollution. Molybdenum-reducing bacteria isolated from soils can be used to remove molybdenum from contaminated environments. In this work we have isolated a local bacterium with the capability to reduce soluble molybdate to the insoluble molybdenum blue. We studied several factors that would optimize molybdate reduction. Electron donor sources such as glucose, sucrose, lactose, maltose and fructose (in decreasing efficiency) supported molybdate reduction after 24 h of incubation with optimum glucose concentration for molybdate reduction at 1.5% (w/v). The optimum pH, phosphate and molybdate concentrations, and temperature for molybdate reduction were pH 6.5, 5.0, 25 to 50 mM and 37 degrees C, respectively. The Mo-blue produced by cellular reduction exhibited a unique absorption spectrum with a maximum peak at 865 nm and a shoulder at 700 nm. Metal ions such as chromium, cadmium, copper, silver and mercury caused approximately 73, 71, 81, 77 and 78% inhibition of the molybdenum-reducing activity, respectively. All of the respiratory inhibitors tested namely rotenone, azide, cyanide and antimycin A did not show any inhibition to the molybdenum-reducing activity suggesting components of the electron transport system are not responsible for the reducing activity. The isolate was tentatively identified as Enterobacter sp. strain Dr.Y13 based on carbon utilization profiles using Biolog GN plates and partial 16S rDNA molecular phylogeny. PMID:19455513

  15. Nitrogen-fixing Enterobacter agglomerans isolated from guts of wood-eating termites.

    PubMed Central

    Potrikus, C J; Breznak, J A

    1977-01-01

    Two strains of facultatively anaerobic, N2-fixing bacteria were isolated from guts of Coptotermes formosanus and identified as Enterobacter agglomerans. The deoxyribonucleic acid base composition of isolates was 52.6 and 53.1 mol% guanine plus cytosine. Both isolates and a known strain of E. agglomerans carried out a mixed acid type of glucose fermentation. N2 fixation by E. agglomerans was inhibited by O2; consequently, N2 served as an N source only for cells growing anaerobically in media lacking a major source of combined N. However, peptone, NH4Cl, or KNO3 served as an N source under either aerobic or anaerobic conditions. It was estimated that 2 x 10(2) cells of E. agglomerans were present per termite gut. This value was 100-fold lower than expected, based on N2 fixation, low recoveries of E. agglomerans may be related to the marked decrease in N2 fixation rates observed when intact termites or their extracted guts were manipulated for the isolation of bacteria. It was concluded that the N2-fixing activity of E. agglomerans may be important to the N economy of C. formosanus. PMID:848958

  16. Decreasing Enterobacter sakazakii (Cronobacter spp.) food contamination level with bacteriophages: prospects and problems.

    PubMed

    Zuber, Sophie; Boissin-Delaporte, Catherine; Michot, Lise; Iversen, Carol; Diep, Benjamin; Brüssow, Harald; Breeuwer, Pieter

    2008-11-01

    Enterobacter sakazakii (Cronobacter spp.) is an opportunistic pathogen, which can cause rare, but life-threatening infections in neonates and infants through feeding of a contaminated milk formula. We isolated 67 phages from environmental samples and tested their lytic host range on a representative collection of 40 E. sakazakii strains. A cocktail of five phages prevented the outgrowth of 35 out of 40 test strains in artificially contaminated infant formula. Two E. sakazakii phages represented prolate head Myoviridae. Molecular tests identified them as close relatives of Escherichia coli phage T4. The remaining three phages represented isometric head Myoviridae with large genome size of 140 and 200 kb, respectively, which belonged to two different DNA hybridization groups. A high dose of 10(8) pfu ml(-1) of phage could effectively sterilize a broth contaminated with both high and low pathogen counts (10(6) and 10(2) cfu ml(-1)). In contrast, broth inoculated with 10(4) phage and 10(2) bacteria per ml first showed normal bacterial growth until reaching a cell titre of 10(5) cfu ml(-1). Only when crossing this threshold, phage replication started, but it could not reduce the contamination level below 100 cfu ml(-1). Phages could be produced with titres of 10(10) pfu ml(-1) in broth culture, but they were not stable upon freeze-drying. Addition of trehalose or milk formula stabilized the phage preparation, which then showed excellent storage stability even at elevated temperature. PMID:21261874

  17. A novel beta-galactosidase capable of glycosyl transfer from Enterobacter agglomerans B1.

    PubMed

    Lu, Lili; Xiao, Min; Xu, Xiaodong; Li, Zhengyi; Li, Yumei

    2007-04-27

    A novel transglycosylating beta-galactosidase was purified from Enterobacter agglomerans B1. It was a homodimer of approximately 248 kDa. The optimal pH and temperature for oNPGal hydrolysis were 7.5-8.0 and 37-40 degrees C, respectively. The K(m) values for oNPGal and lactose were 0.06 and 114 mM, respectively. The enzyme produced galacto-oligosaccharides in a 38% yield at the lactose concentration of 12.5% (w/v). When using oNPGal as donor, the enzyme was able to catalyze glycosyl transfer to a series of acceptors, including hexose, pentose, beta- or alpha-disaccharides, hexahydroxy alcohol, cyclitol, and aromatic glycosides. This suggested the enzyme to be a potential synthetic tool for preparing galactose-containing chemicals. The gene encoding this enzyme was cloned by degenerate PCR and TAIL-PCR. It revealed an ORF of 3090 nucleotides encoding a 1029 amino-acid protein, which had been expressed in Escherichia coli. Transferase activities in both recombinant and natural enzymes were similar. PMID:17336932

  18. Isolation of Enterobacter sakazakii from ass' milk in Sicily: case report, safety and legal issues.

    PubMed

    Conte, F; Passantino, A

    2008-07-01

    Enterobacter sakazakii (Es) infections are likely to involve newborns and infants, causing meningitis and necrotizing enterocolitis and sepsis. Contamination of infant formulae milk during factory production or bottle preparation is implicated. Es has been isolated from environmental sources and from food other than infant formula and milk powder, but why it is associated only with the consumption of infant formulae, is unclear. According to Regulation (EC) No. 2073/2005 on the microbiological criteria for foodstuffs, Es is considered a microorganisms of greatest concern in infant formulae and follow-on formulae. Es is included between "safety criteria". The isolation of two strains of Es from 50 samples of ass' milk in Sicily is described. The antibiotic resistance profile of the isolates revealed a multiple resistance profile, including fluoroquinolones, commonly used to treat the infections. The authors underline the importance of survey because in Italy ass' milk is considered one of the solutions for infants suffering from hypersensitivity to milk protein of some animal species. There is scarce information about the ecology and the uncertainty concerning the source of infection in the children and adults; the authors are concerned that ass' milk could become a high-risk food. PMID:18571118

  19. Physiologic Mechanisms Involved in Accumulation of 3-Hydroxypropionaldehyde during Fermentation of Glycerol by Enterobacter agglomerans

    PubMed Central

    Barbirato, F.; Soucaille, P.; Bories, A.

    1996-01-01

    When grown in 700 mM glycerol within the pH range 6.0 to 7.5, anaerobic pH-regulated cultures of Enterobacter agglomerans exhibited an extracellular accumulation of 3-hydroxypropionaldehyde (3-HPA). This phenomenon, which causes fermentation cessation, occurred earlier when pH was low. In contrast, substrate consumption was complete at pH 8. Levels of glycerol-catabolizing enzymes, i.e., glycerol dehydrogenase and dihydroxyacetone kinase for the oxidative route and glycerol dehydratase and 1,3-propanediol dehydrogenase for the reductive route, as well as the nucleotide pools were determined periodically in the pH 7- and pH 8-regulated cultures. A NAD/NADH ratio of 1.7 was correlated with the beginning of the production of the inhibitory metabolite. Further accumulation was dependent on the ratio of glycerol dehydratase activity to 1,3-propanediol dehydrogenase activity. For a ratio higher than 1, 3-HPA was produced until fermentation ceased, which occurred for the pH 7-regulated culture. At pH 8, a value below 1 was noticed and 3-HPA accumulation was transient, while the NAD/NADH ratio decreased. The low rate of glycerol dissimilation following the appearance of 3-HPA in the culture medium was attributed to the strong inhibitory effect exerted by 3-HPA on glycerol dehydrogenase activity. PMID:16535461

  20. Behavior of Enterobacter pulveris in amorphous and crystalline powder matrices treated with supercritical carbon dioxide.

    PubMed

    Callanan, M; Paes, M; Iversen, C; Kleijn, R; Bravo Almeida, C; Peñaloza, W; Johnson, N; Vuataz, G; Michel, M

    2012-11-01

    The resistance of an Enterobacter pulveris strain to combined heat and supercritical carbon dioxide (scCO(2)) treatments in different powder matrices was examined. The strain proved resistant to scCO(2) treatment up to 50 MPa pressure at temperatures >73 °C for at least 20 min in a commercial infant formula. Water availability was shown to be important for the observed thermotolerance, because introduction of water in the scCO(2) gas flow during treatment resulted in a 1 log(10) cfu/g reduction of the initial inoculum. Interestingly, similar tolerance to heat and scCO(2) treatment was observed in a less complex matrix, a maltodextrin powder. In contrast, the bacterial strain proved sensitive to lower temperatures (55-65 °C) over shorter times (≤10 min) in a dextrose powder composed of crystalline particles. Therefore, the microorganism demonstrates heat sensitivity in the crystalline powder matrix closer to that of nonpowder liquid matrices. These data demonstrate the increased heat tolerance of the bacterium specifically in amorphous powders and indicate that this characteristic is not dependent on fat and other components commonly found in infant formula. The information is important in designing strategies to deal with contamination of powders with Enterobacteriacae, including pathogenic Cronobacter spp. PMID:22959935

  1. Inactivation of Enterobacter sakazakii of dehydrated infant formula by gamma-irradiation

    NASA Astrophysics Data System (ADS)

    Lee, Ju-Woon; Oh, Sang-Hee; Byun, Eui-Baek; Kim, Jae-Hun; Kim, Jang-Ho; Woon, Jae-Ho; Byun, Myung-Woo

    2007-11-01

    Enterobacter sakazakii has been implicated as a causal organism in a severe form of neonatal meningitis, with reported mortality rates of 20%. The population at greatest risk is immunocompromised infants of any age. Dried infant formula has been identified as a potential source of the organism in both outbreaks and sporadic cases. The objective of this study was to investigate theirradiation effect of the inactivation on E. sakazakii (ATCC 29544) of a dehydrated infant formula. The D10-values were 0.22-0.27 and 0.76 kGy for broth and dehydrated infant formula, respectively. The irradiation at 5.0 kGy was able to completely eliminate the E. sakazakii inoculated at 8.0 to 9.0 log CFU g -1 onto a dehydrated infant formula. There was no regrowth for all samples during the time they were stored at 10 °C for 6 h after rehydration. The present results indicated that a gamma-irradiation could potentially be used to inactivate E. sakazakii in a dehydrated powdered infant formula.

  2. Evaluation of an automated repetitive sequence-based PCR system for subtyping Enterobacter sakazakii.

    PubMed

    Healy, B; Mullane, N; Collin, V; Mailler, S; Iversen, C; Chatellier, S; Storrs, M; Fanning, S

    2008-07-01

    Enterobacter sakazakii is regarded as a ubiquitous organism that can be isolated from a wide range of foods and environments. Infection in at-risk infants has been epidemiologically linked to the consumption of contaminated powdered infant formula. Preventing the dissemination of this pathogen in a powdered infant formula manufacturing facility is an important step in ensuring consumer confidence in a given brand together with the protection of the health status of a vulnerable population. In this study we report the application of a repetitive sequence-based PCR typing method to subtype a previously well-characterized collection of E. sakazakii isolates of diverse origin. While both methods successfully discriminated between the collection of isolates, repetitive sequence-based PCR identified 65 types, whereas pulsed-field gel electrophoresis identified 110 types showing > or =95% similarity. The method was quick and easy to perform, and our data demonstrated the utility and value of this approach to monitor in-process contamination, which could potentially contribute to a reduction in the transmission of E. sakazakii. PMID:18680935

  3. Evidence supporting dissimilatory and assimilatory lignin degradation in Enterobacter lignolyticus SCF1

    PubMed Central

    DeAngelis, Kristen M.; Sharma, Deepak; Varney, Rebecca; Simmons, Blake; Isern, Nancy G.; Markilllie, Lye Meng; Nicora, Carrie; Norbeck, Angela D.; Taylor, Ronald C.; Aldrich, Joshua T.; Robinson, Errol W.

    2013-01-01

    Lignocellulosic biofuels are promising as sustainable alternative fuels, but lignin inhibits access of enzymes to cellulose, and by-products of lignin degradation can be toxic to cells. The fast growth, high efficiency and specificity of enzymes employed in the anaerobic litter deconstruction carried out by tropical soil bacteria make these organisms useful templates for improving biofuel production. The facultative anaerobe Enterobacter lignolyticus SCF1 was initially cultivated from Cloud Forest soils in the Luquillo Experimental Forest in Puerto Rico, based on anaerobic growth on lignin as sole carbon source. The source of the isolate was tropical forest soils that decompose litter rapidly with low and fluctuating redox potentials, where bacteria using oxygen-independent enzymes likely play an important role in decomposition. We have used transcriptomics and proteomics to examine the observed increased growth of SCF1 grown on media amended with lignin compared to unamended growth. Proteomics suggested accelerated xylose uptake and metabolism under lignin-amended growth, with up-regulation of proteins involved in lignin degradation via the 4-hydroxyphenylacetate degradation pathway, catalase/peroxidase enzymes, and the glutathione biosynthesis and glutathione S-transferase (GST) proteins. We also observed increased production of NADH-quinone oxidoreductase, other electron transport chain proteins, and ATP synthase and ATP-binding cassette (ABC) transporters. This suggested the use of lignin as terminal electron acceptor. We detected significant lignin degradation over time by absorbance, and also used metabolomics to demonstrate moderately significant decreased xylose concentrations as well as increased metabolic products acetate and formate in stationary phase in lignin-amended compared to unamended growth conditions. Our data show the advantages of a multi-omics approach toward providing insights as to how lignin may be used in nature by microorganisms coping

  4. Inactivation of Enterobacter sakazakii in reconstituted infant formula by trans-cinnamaldehyde.

    PubMed

    Amalaradjou, Mary Anne Roshni; Hoagland, Thomas A; Venkitanarayanan, Kumar

    2009-02-15

    Enterobacter sakazakii is an emerging pathogen which causes a life-threatening form of meningitis, necrotizing colitis and meningoencephalitis in neonates and children. Epidemiological studies implicate dried infant formula as the principal source of the pathogen. Trans-cinnamaldehyde is a major component of bark extract of cinnamon. It is classified as generally recognized as safe (GRAS) by the U.S. Food and Drug Administration, and is approved for use in food (21 CFR 182.60). The objective of this study was to determine the antibacterial effect of trans-cinnamaldehyde on E. sakazakii in reconstituted infant formula. A 5-strain mixture of E. sakazakii was inoculated into 10 ml samples of reconstituted infant formula (at 6.0 log CFU/ml) containing 0%, 0.15%, 0.3% or 0.5% trans-cinnamaldehyde. The samples were incubated at 37, 23, 8 or 4 degrees C for 0, 6, 10 and 24 h, and the surviving populations of E. sakazakii at each sampling time were enumerated. In addition, potential cytotoxicity of trans-cinnamaldehyde, if any, was determined on human embryonic intestinal cells (INT-407). The treatments containing trans-cinnamaldehyde significantly reduced (P<0.05) the population of E. sakazakii, compared to the controls. Trans-cinnamaldehyde (0.5%) reduced the pathogen to undetectable levels by 4 h of incubation at 37 or 23 degrees C and 10 h of incubation at 8 or 4 degrees C, respectively. Trans-cinnamaldehyde produced no cytotoxic effects on human embryonic intestinal cells at the tested concentrations. Results indicate that trans-cinnamaldehyde could potentially be used to kill E. sakazakii in reconstituted infant formula, however sensory studies are warranted before recommending its use. PMID:19091435

  5. Survival Strategies of the Plant-Associated Bacterium Enterobacter sp. Strain EG16 under Cadmium Stress

    PubMed Central

    Chen, Yanmei; Li, Yaying; Lin, Qingqi; Bai, Jun; Tang, Lu; Wang, Shizhong; Ying, Rongrong

    2016-01-01

    Plant-associated bacteria are of great interest because of their potential use in phytoremediation. However, their ability to survive and promote plant growth in metal-polluted soils remains unclear. In this study, a soilborne Cd-resistant bacterium was isolated and identified as Enterobacter sp. strain EG16. It tolerates high external Cd concentrations (Cd2+ MIC, >250 mg liter−1) and is able to produce siderophores and the plant hormone indole-3-acetic acid (IAA), both of which contribute to plant growth promotion. Surface biosorption in this strain accounted for 31% of the total Cd accumulated. The potential presence of cadmium sulfide, shown by energy-dispersive X-ray (EDX) analysis, suggested intracellular Cd binding as a Cd response mechanism of the isolate. Cd exposure resulted in global regulation at the transcriptomic level, with the bacterium switching to an energy-conserving mode by inhibiting energy-consuming processes while increasing the production of stress-related proteins. The stress response system included increased import of sulfur and iron, which become deficient under Cd stress, and the redirection of sulfur metabolism to the maintenance of intracellular glutathione levels in response to Cd toxicity. Increased production of siderophores, responding to Cd-induced Fe deficiency, not only is involved in the Cd stress response systems of EG16 but may also play an important role in promoting plant growth as well as alleviating the Cd-induced inhibition of IAA production. The newly isolated strain EG16 may be a suitable candidate for microbially assisted phytoremediation due to its high resistance to Cd and its Cd-induced siderophore production, which is likely to contribute to plant growth promotion. PMID:26729719

  6. Survival Strategies of the Plant-Associated Bacterium Enterobacter sp. Strain EG16 under Cadmium Stress.

    PubMed

    Chen, Yanmei; Chao, Yuanqing; Li, Yaying; Lin, Qingqi; Bai, Jun; Tang, Lu; Wang, Shizhong; Ying, Rongrong; Qiu, Rongliang

    2016-01-01

    Plant-associated bacteria are of great interest because of their potential use in phytoremediation. However, their ability to survive and promote plant growth in metal-polluted soils remains unclear. In this study, a soilborne Cd-resistant bacterium was isolated and identified as Enterobacter sp. strain EG16. It tolerates high external Cd concentrations (Cd(2+) MIC, >250 mg liter(-1)) and is able to produce siderophores and the plant hormone indole-3-acetic acid (IAA), both of which contribute to plant growth promotion. Surface biosorption in this strain accounted for 31% of the total Cd accumulated. The potential presence of cadmium sulfide, shown by energy-dispersive X-ray (EDX) analysis, suggested intracellular Cd binding as a Cd response mechanism of the isolate. Cd exposure resulted in global regulation at the transcriptomic level, with the bacterium switching to an energy-conserving mode by inhibiting energy-consuming processes while increasing the production of stress-related proteins. The stress response system included increased import of sulfur and iron, which become deficient under Cd stress, and the redirection of sulfur metabolism to the maintenance of intracellular glutathione levels in response to Cd toxicity. Increased production of siderophores, responding to Cd-induced Fe deficiency, not only is involved in the Cd stress response systems of EG16 but may also play an important role in promoting plant growth as well as alleviating the Cd-induced inhibition of IAA production. The newly isolated strain EG16 may be a suitable candidate for microbially assisted phytoremediation due to its high resistance to Cd and its Cd-induced siderophore production, which is likely to contribute to plant growth promotion. PMID:26729719

  7. Attachment of and Biofilm Formation by Enterobacter sakazakii on Stainless Steel and Enteral Feeding Tubes

    PubMed Central

    Kim, Hoikyung; Ryu, Jee-Hoon; Beuchat, Larry R.

    2006-01-01

    Enterobacter sakazakii has been reported to form biofilms, but environmental conditions affecting attachment to and biofilm formation on abiotic surfaces have not been described. We did a study to determine the effects of temperature and nutrient availability on attachment and biofilm formation by E. sakazakii on stainless steel and enteral feeding tubes. Five strains grown to stationary phase in tryptic soy broth (TSB), infant formula broth (IFB), or lettuce juice broth (LJB) at 12 and 25°C were examined for the extent to which they attach to these materials. Higher populations attached at 25°C than at 12°C. Stainless steel coupons and enteral feeding tubes were immersed for 24 h at 4°C in phosphate-buffered saline suspensions (7 log CFU/ml) to facilitate the attachment of 5.33 to 5.51 and 5.03 to 5.12 log CFU/cm2, respectively, before they were immersed in TSB, IFB, or LJB, followed by incubation at 12 or 25°C for up to 10 days. Biofilms were not produced at 12°C. The number of cells of test strains increased by 1.42 to 1.67 log CFU/cm2 and 1.16 to 1.31 log CFU/cm2 in biofilms formed on stainless steel and feeding tubes, respectively, immersed in IFB at 25°C; biofilms were not formed on TSB and LJB at 25°C, indicating that nutrient availability plays a major role in processes leading to biofilm formation on the surfaces of these inert materials. These observations emphasize the importance of temperature control in reconstituted infant formula preparation and storage areas in preventing attachment and biofilm formation by E. sakazakii. PMID:16957203

  8. Biodegradation of Chlorpyrifos by Enterobacter Strain B-14 and Its Use in Bioremediation of Contaminated Soils

    PubMed Central

    Singh, Brajesh K.; Walker, Allan; Morgan, J. Alun W.; Wright, Denis J.

    2004-01-01

    Six chlorpyrifos-degrading bacteria were isolated from an Australian soil and compared by biochemical and molecular methods. The isolates were indistinguishable, and one (strain B-14) was selected for further analysis. This strain showed greatest similarity to members of the order Enterobacteriales and was closest to members of the Enterobacter asburiae group. The ability of the strain to mineralize chlorpyrifos was investigated under different culture conditions, and the strain utilized chlorpyrifos as the sole source of carbon and phosphorus. Studies with ring or uniformly labeled [14C]chlorpyrifos in liquid culture demonstrated that the isolate hydrolyzed chlorpyrifos to diethylthiophospshate (DETP) and 3, 5, 6-trichloro-2-pyridinol, and utilized DETP for growth and energy. The isolate was found to possess mono- and diphosphatase activities along with a phosphotriesterase activity. Addition of other sources of carbon (glucose and succinate) resulted in slowing down of the initial rate of degradation of chlorpyrifos. The isolate degraded the DETP-containing organophosphates parathion, diazinon, coumaphos, and isazofos when provided as the sole source of carbon and phosphorus, but not fenamiphos, fonofos, ethoprop, and cadusafos, which have different side chains. Studies of the molecular basis of degradation suggested that the degrading ability could be polygenic and chromosome based. Further studies revealed that the strain possessed a novel phosphotriesterase enzyme system, as the gene coding for this enzyme had a different sequence from the widely studied organophosphate-degrading gene (opd). The addition of strain B-14 (106 cells g−1) to soil with a low indigenous population of chlorpyrifos-degrading bacteria treated with 35 mg of chlorpyrifos kg−1 resulted in a higher degradation rate than was observed in noninoculated soils. These results highlight the potential of this bacterium to be used in the cleanup of contaminated pesticide waste in the

  9. Enterobacter sakazakii in food and beverages (other than infant formula and milk powder).

    PubMed

    Friedemann, Miriam

    2007-05-01

    The ubiqitous microorganism Enterobacter sakazakii is a rare contaminant of infant formula and may cause severe systemic infection in neonates. So far, other food is not known to cause E. sakazakii-infections. The scarce information about the ecology of E. sakazakii and the uncertainty concerning the source of infection in children and adults warrant a summary of the current knowledge about the presence of this opportunistic microorganism in food other than infant formula. This review systematizes publications on the presence of E. sakazakii in food and beverages until June 2006. Food other than infant formula has been rarely investigated for the presence of E. sakazakii. Nevertheless, this microorganism could be isolated from a wide spectrum of food and food ingredients. E. sakazakii was isolated from plant food and food ingredients like cereal, fruit and vegetables, legume products, herbs and spices as well as from animal food sources like milk, meat and fish and products made from these foods. The spectrum of E. sakazakii-contaminated food covers both raw and processed food. The kind of processing of E. sakazakii-contaminated food was not restricted to dry products. Fresh, frozen, ready-to-eat, fermented and cooked food products as well as beverages and water suitable for the preparation of food, were found to be contaminated by E. sakazakii. Although E. sakazakii-contaminated food do not have general public health significance, measures for prevention should consider the presence of E. sakazakii in food, food ingredients, their processing and preparation as possible source of contamination, colonization or infection. PMID:17331606

  10. Optimization of biodegradable plastic production on sugar cane molasses in Enterobacter sp. SEL2

    PubMed Central

    Naheed, Nighat; Jamil, Nazia

    2014-01-01

    Contaminated environments have a large number of bacteria which can accumulate PHA as their energy reserves. Out of 54 isolated bacterial strains from three groups of contaminated sites 48 were found PHA positive. The sites were grouped on the basis of the type of carbon sources i.e. sugars, fatty acids and much diverse type. Strains MFD5, MFD11, UML3, USL2, SEL2, SEL3, SEL10 and PFW1 produced 69.9 ± 0.29, 75.27 ± 0.45, 65.43 ± 0.1, 72.54 ± 0.27, 76.61 ± 0.28, 61.81 ± 0.05, 71.16 ± 0.09 and 74.92 ± 0.5 percent of PHA to their constant cell weight (CCW) respectively in PHA detection media supplemented with 2% glucose. Molasses, whey, crumbs hydrolysate and palm oil were checked as inexpensive carbon sources. Molasses alone could supply the required nutrients for growth and PHA production. Strain SEL2 produced 47.36 ± 0.45% PHA using 2% molasses at 37 °C and pH 7.0. Upon production optimization the best accumulation (80.95 ± 0.01%) was observed in PHA detection media with 0.2% nitrogen source, 3% molasses, pH 5.0 and 37 °C by the strain SEL2. The overall effect of the presence of increased molasses concentration in the media was positive it increased the accumulation period till 72 h. Enterobacter sp. SEL2 (JF901810) is first time being reported for PHA production. PMID:25242924

  11. Evidence supporting dissimilatory and assimilatory lignin degradation in Enterobacter lignolyticus SCF1.

    PubMed

    Deangelis, Kristen M; Sharma, Deepak; Varney, Rebecca; Simmons, Blake; Isern, Nancy G; Markilllie, Lye Meng; Nicora, Carrie; Norbeck, Angela D; Taylor, Ronald C; Aldrich, Joshua T; Robinson, Errol W

    2013-01-01

    Lignocellulosic biofuels are promising as sustainable alternative fuels, but lignin inhibits access of enzymes to cellulose, and by-products of lignin degradation can be toxic to cells. The fast growth, high efficiency and specificity of enzymes employed in the anaerobic litter deconstruction carried out by tropical soil bacteria make these organisms useful templates for improving biofuel production. The facultative anaerobe Enterobacter lignolyticus SCF1 was initially cultivated from Cloud Forest soils in the Luquillo Experimental Forest in Puerto Rico, based on anaerobic growth on lignin as sole carbon source. The source of the isolate was tropical forest soils that decompose litter rapidly with low and fluctuating redox potentials, where bacteria using oxygen-independent enzymes likely play an important role in decomposition. We have used transcriptomics and proteomics to examine the observed increased growth of SCF1 grown on media amended with lignin compared to unamended growth. Proteomics suggested accelerated xylose uptake and metabolism under lignin-amended growth, with up-regulation of proteins involved in lignin degradation via the 4-hydroxyphenylacetate degradation pathway, catalase/peroxidase enzymes, and the glutathione biosynthesis and glutathione S-transferase (GST) proteins. We also observed increased production of NADH-quinone oxidoreductase, other electron transport chain proteins, and ATP synthase and ATP-binding cassette (ABC) transporters. This suggested the use of lignin as terminal electron acceptor. We detected significant lignin degradation over time by absorbance, and also used metabolomics to demonstrate moderately significant decreased xylose concentrations as well as increased metabolic products acetate and formate in stationary phase in lignin-amended compared to unamended growth conditions. Our data show the advantages of a multi-omics approach toward providing insights as to how lignin may be used in nature by microorganisms coping

  12. Optimization of biodegradable plastic production on sugar cane molasses in Enterobacter sp. SEL2.

    PubMed

    Naheed, Nighat; Jamil, Nazia

    2014-01-01

    Contaminated environments have a large number of bacteria which can accumulate PHA as their energy reserves. Out of 54 isolated bacterial strains from three groups of contaminated sites 48 were found PHA positive. The sites were grouped on the basis of the type of carbon sources i.e. sugars, fatty acids and much diverse type. Strains MFD5, MFD11, UML3, USL2, SEL2, SEL3, SEL10 and PFW1 produced 69.9 ± 0.29, 75.27 ± 0.45, 65.43 ± 0.1, 72.54 ± 0.27, 76.61 ± 0.28, 61.81 ± 0.05, 71.16 ± 0.09 and 74.92 ± 0.5 percent of PHA to their constant cell weight (CCW) respectively in PHA detection media supplemented with 2% glucose. Molasses, whey, crumbs hydrolysate and palm oil were checked as inexpensive carbon sources. Molasses alone could supply the required nutrients for growth and PHA production. Strain SEL2 produced 47.36 ± 0.45% PHA using 2% molasses at 37 °C and pH 7.0. Upon production optimization the best accumulation (80.95 ± 0.01%) was observed in PHA detection media with 0.2% nitrogen source, 3% molasses, pH 5.0 and 37 °C by the strain SEL2. The overall effect of the presence of increased molasses concentration in the media was positive it increased the accumulation period till 72 h. Enterobacter sp. SEL2 (JF901810) is first time being reported for PHA production. PMID:25242924

  13. [Utility of pyrrolidonyl-arylamidase detection for typing Enterobacteriaceae and non-fermenting Gram-negative bacteria].

    PubMed

    Nicola, F; Centorbi, H; Bantar, C; Smayevsky, J; Bianchini, H

    1995-01-01

    Detection of pyrrolidonyl-aryl-amidase activity (PYR) is an important tool to identify gram-positive cocci, such as staphylococci, enterococci, streptococci, and other related genera. However, only few studies evaluating its usefulness with gram-negative rods have been published. Thus, a prospective study including 542 and 215 unique clinical isolates of Enterobacteriaceae and non-fermentative gram-negative rods, respectively, was undertaken. Strains were identified by conventional methods. PYR test was performed using a commercial kit, according to the manufacturer recommendations. Positive results were uniformly obtained for the PYR test with the following species: Citrobacter spp, Klebsiella spp, Enterobacter aerogenes, Enterobacter agglomerans group, Serratia marcescens and S. odorifera. On the other hand, negative results were uniformly displayed by E. coli (including inactive E. coli), Protease group, Salmonellia spp, Shigella spp, Acinetobacter spp, Burkholderia (Pseudomonas) cepacia and Flavobacterium spp. Variable results were shown in Pseudomonas aeruginosa, Stenotrophomonas (xanthomonas) malthophilia, Kluyvera cryocrescens, and Enterobacter cloacae. PYR test proved to be a reliable and simple tool to rapidly distinguish certain species belonging to Enterobacteriaceae (ie. Citrobacter freundii from Salmonella spp, and inactive E. coli from K. ozaenae). Further studies, including a wide diversity of species, are required to assess usefulness of the PYR test for the identification of non-fermentative gram-negative rods. PMID:8850133

  14. Inactivation of Enterobacter sakazakii, Bacillus cereus, and Salmonella typhimurium in powdered weaning food by electron-beam irradiation

    NASA Astrophysics Data System (ADS)

    Hong, Yun-Hee; Park, Ji-Yong; Park, Jong-Hyun; Chung, Myong-Soo; Kwon, Ki-Sung; Chung, Kyungsook; Won, Misun; Song, Kyung-Bin

    2008-09-01

    Inactivation of Enterobacter sakazakii, Bacillus cereus, and Salmonella typhimurium were evaluated in powdered weaning food using electron-beam irradiation. E. sakazakii, B. cereus, and S. typhimurium were eliminated by irradiation at 16, 8, and 8 kGy, respectively. The D10-vlaues of E. sakazakii, B. cereus, and S. typhimurium inoculated on powdered weaning food were 4.83, 1.22, and 0.98 kGy, respectively. The results suggest that electron-beam irradiation should inhibit the growth of pathogenic bacteria on baby food without impairing qualities.

  15. Impact of probiotic drugs, based on Enterobacter faecium autostrains, on human intestinal microflora in confined habitat

    NASA Astrophysics Data System (ADS)

    Viacheslav, Ilyin; Batov, Alexey; Usanova, Nonna

    The aim of research: Investigation of influence of probiotic drugs based on autostrains of Enter-obacter faecium, selected from the crew in long term isolation experiment in confined habitat. It is known that during long-term presence in confined habitat the risk of infectious diseases increases. One of the main infectious risk occurs during first 20 days of isolation as a result of exchange of strains and stress-mediated disbacterioses. Therefore it is necessary to evaluate activities of probiotics to avoid this risk. Furthermore, in case of super long term autonomous flight there should be possibilities of application of autochthonous microflora strains as pro-biotics to strengthen colonial resistance of crews. Materials and methods: In the experiment there were used probiotic drugs based on autostrains of E. faecium, selected from the crew before the experiment. Probiotic drugs were consumed during 30 days since the beginning of the experiment with the break of consumption between 10th to 19th day. Results: Comparing the state of intestinal microflora of the crew on the baseline and 14th day of experiment re-vealed remarkable changes of microflora: the increasing of concentration of bifidobacteria and E. faecium (approximately 10 times), elimination of hemolytic streptococcus, yeasts, reduction of the rate of S.aureus, hemolytic gramnegative non-fermenting rods, lactobacilli and normal E.coli. On the 45th day of isolation, 15 days after finishing of auto-strains administration, there fere signs of restoration of disbacteriosis: the quantitative decreasing lactobacilli, bifidobacteria and normal E.coli, increasing of the rate of S.aureus, hemolytic gramnegative nonfermentive rods. Conclusion: Thus we managed to avoid risk of pathogenicity potential growth in first 2 decades of isolation. Application of probiotic, based on the autostrains of E. faecium leads to insignificant changes of concentration of lactobacteries, bifidobacteries, normal E. coli and to

  16. Exploring multi-metal biosorption by indigenous metal-hyperresistant Enterobacter sp. J1 using experimental design methodologies.

    PubMed

    Lu, Wei-Bin; Kao, Wei-Chen; Shi, Jun-Ji; Chang, Jo-Shu

    2008-05-01

    A novel experimental design, combining mixture design and response surface methodology (RSM), was developed to investigate the competitive adsorption behavior of lead, copper and cadmium by an indigenous isolate Enterobacter sp. J1 able to tolerate high concentrations of a variety of heavy metals. Using the proposed combinative experimental design, two different experiment designs in a ternary metal biosorption system can be integrated to a succinct experiment and the number of experimental trials was markedly reduced from 38 to 26 by reusing the mutual experimental data. Triangular contour diagrams and triangular three-dimensional surface plots were generated to describe the ternary metal biosorption equilibrium data in mixture design systems. The results show that the preference of metal sorption of Enterobacter sp. J1 decreased in the order of Pb(2+)>Cu(2+)>Cd(2+). The presence of other metals resulted in a competitive effect. The influence of the other two metals in ternary metal biosorption system can be easily determined by comparing the stray distance from the single metal biosorption. The behavior of competitive biosorption was successfully described and predicted using a combined Langmuir-Freundlich model along with new three-dimensional contour-surface plots. PMID:17913351

  17. Studies on the accessory reproductive organs in the drake. 2. Macroscopic and microscopic observatorys on the cloaca of the drake with special reference to the ejaculatory groove region.

    PubMed

    Fujihara, N; Nishiyama, H; Nakashima, N

    1976-05-01

    The anatomical structure of the ejaculatory groove region (EGR) of the drake was investigated macro- and microscopically in connection with its function. The EGR covers a part of the urodeum and the second fold of the cloaca. The EGR is unique to the males and is characterized by red colored appearance and less smooth surface of the mucosa. The mucosa of EGR forms folds giving less smooth surface to it and is lined with psuedostratified columnar epithelium. A vascular layer which contains many capillaries and lymphocytes and gives red color to the mucosa lies just beneath the epithelium. The EGR develops at puberty together with the developments of the testis and the penis. Blood supply and the arrangement of the lymphatic sinuses of EGR were described and their functions were discussed. PMID:935059

  18. Comprehensive approaches for molecular biomarker discovery for the detection and identification of Cronobacter spp. (Enterobacter sakazakii), Salmonella, and other foodborne pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cronobacter spp. (formerly Enterobacter sakazakii) and Salmonella are increasingly implicated as important bacterial contaminants in low-moisture food products, including powdered infant formula. Estimates indicate that 40-80% of infants infected with C. sakazakii and/or Salmonella in the U.S. may ...

  19. Effect of acetate upon the formation of acetoin in Klebsiella and Enterobacter and it possible practical application in a rapid voges-proskauer test.

    PubMed

    Bryn, K; Ulstrup, J C; Stormer, F C

    1973-03-01

    Acetate stimulates the formation of acetoin during 1-h incubation of Voges-Proskauer-positive strains of Klebsiella and Enterobacter. Of these organisms, 124 of 126 strains were recognized as positive in the presence of acetate, and 106 were recognized as positive in its absence. PMID:4572901

  20. Improvement of plant growth and seed yield in Jatropha curcas by a novel nitrogen-fixing root associated Enterobacter species

    PubMed Central

    2013-01-01

    Background Jatropha curcas L. is an oil seed producing non-leguminous tropical shrub that has good potential to be a fuel plant that can be cultivated on marginal land. Due to the low nutrient content of the targeted plantation area, the requirement for fertilizer is expected to be higher than other plants. This factor severely affects the commercial viability of J. curcas. Results We explored the feasibility to use endophytic nitrogen-fixing bacteria that are native to J. curcas to improve plant growth, biomass and seed productivity. We demonstrated that a novel N-fixing endophyte, Enterobacter sp. R4-368, was able to colonize in root and stem tissues and significantly promoted early plant growth and seed productivity of J. curcas in sterilized and non-sterilized soil. Inoculation of young seedling led to an approximately 57.2% increase in seedling vigour over a six week period. At 90 days after planting, inoculated plants showed an average increase of 25.3%, 77.7%, 27.5%, 45.8% in plant height, leaf number, chlorophyll content and stem volume, respectively. Notably, inoculation of the strain led to a 49.0% increase in the average seed number per plant and 20% increase in the average single seed weight when plants were maintained for 1.5 years in non-sterilized soil in pots in the open air. Enterobacter sp. R4-368 cells were able to colonize root tissues and moved systemically to stem tissues. However, no bacteria were found in leaves. Promotion of plant growth and leaf nitrogen content by the strain was partially lost in nifH, nifD, nifK knockout mutants, suggesting the presence of other growth promoting factors that are associated with this bacterium strain. Conclusion Our results showed that Enterobacter sp. R4-368 significantly promoted growth and seed yield of J. curcas. The application of the strains is likely to significantly improve the commercial viability of J. curcas due to the reduced fertilizer cost and improved oil yield. PMID:24083555

  1. Q-PCR Based Culture-Independent Enumeration and Detection of Enterobacter: An Emerging Environmental Human Pathogen in Riverine Systems and Potable Water.

    PubMed

    Patel, Chandra B; Shanker, Rishi; Gupta, Vijai K; Upadhyay, Ram S

    2016-01-01

    The availability of safe and pristine water is a global challenge when large numbers of natural and anthropogenic water resources are being depleted with faster rate. The remaining water resources are severely contaminated with various kinds of contaminants including microorganisms. Enterobacter is one of the fecal coliform bacteria of family Enterobacteriaceae. Enterobacter was earlier used as an indicator bacterium along with other fecal Coliforms namely Escherichia coli, Citrobacter, and Klebsiella, but it is now known to cause various diseases in human beings. In this study, we have collected 55 samples from potable water and riverine system and proved their presence using their conserved sequences of 16S rRNA and 23S rRNA genes with the help of SYBR green real-time PCR, which showed very high specificity for the detection of Enterobacter. The Enterobacter counts in potable water were found to 1290 ± 32.89 to 1460 ± 39.42 cfu/100 ml. The Enterobacter levels in surface water were 1.76 × 10(4) ± 492, 1.33 × 10(4) ± 334, 1.15 × 10(4) ± 308, 2.56 × 10(4) ± 802, 2.89 × 10(4) ± 962, 8.16 × 10(4) ± 3443 cfu/100 ml; the levels of Enterobacter contamination associated with hydrophytes were 4.80 × 10(4) ± 1804, 3.48 × 10(4) ± 856, 8.50 × 10(4) ± 2074, 8.09 × 10(4) ± 1724, 6.30 × 10(4) ± 1738, 3.68 × 10(4) ± 949 cfu/10 g and the Enterobacter counts in sediments of the river, were 2.36 × 10(4) ± 703, 1.98 × 10(4) ± 530, 9.92 × 10(4) ± 3839, 6.80 × 10(4) ± 2230, 8.76 × 10(4) ± 3066 and 2.34 × 10(4) ± 732 cfu/10 g at the sampling Site #1, Site #2, Site #3, Site #4, Site #5, and Site #6, respectively. The assay could be used for the regular monitoring of potable water and other water reservoirs to check waterborne outbreaks. PMID:26925044

  2. Q-PCR Based Culture-Independent Enumeration and Detection of Enterobacter: An Emerging Environmental Human Pathogen in Riverine Systems and Potable Water

    PubMed Central

    Patel, Chandra B.; Shanker, Rishi; Gupta, Vijai K.; Upadhyay, Ram S.

    2016-01-01

    The availability of safe and pristine water is a global challenge when large numbers of natural and anthropogenic water resources are being depleted with faster rate. The remaining water resources are severely contaminated with various kinds of contaminants including microorganisms. Enterobacter is one of the fecal coliform bacteria of family Enterobacteriaceae. Enterobacter was earlier used as an indicator bacterium along with other fecal Coliforms namely Escherichia coli, Citrobacter, and Klebsiella, but it is now known to cause various diseases in human beings. In this study, we have collected 55 samples from potable water and riverine system and proved their presence using their conserved sequences of 16S rRNA and 23S rRNA genes with the help of SYBR green real-time PCR, which showed very high specificity for the detection of Enterobacter. The Enterobacter counts in potable water were found to 1290 ± 32.89 to 1460 ± 39.42 cfu/100 ml. The Enterobacter levels in surface water were 1.76 × 104 ± 492, 1.33 × 104 ± 334, 1.15 × 104 ± 308, 2.56 × 104 ± 802, 2.89 × 104 ± 962, 8.16 × 104 ± 3443 cfu/100 ml; the levels of Enterobacter contamination associated with hydrophytes were 4.80 × 104 ± 1804, 3.48 × 104 ± 856, 8.50 × 104 ± 2074, 8.09 × 104 ± 1724, 6.30 × 104 ± 1738, 3.68 × 104 ± 949 cfu/10 g and the Enterobacter counts in sediments of the river, were 2.36 × 104 ± 703, 1.98 × 104 ± 530, 9.92 × 104 ± 3839, 6.80 × 104 ± 2230, 8.76 × 104 ± 3066 and 2.34 × 104 ± 732 cfu/10 g at the sampling Site #1, Site #2, Site #3, Site #4, Site #5, and Site #6, respectively. The assay could be used for the regular monitoring of potable water and other water reservoirs to check waterborne outbreaks. PMID:26925044

  3. Entericidin is required for a probiotic treatment (Enterobacter sp. strain C6-6) to protect trout from cold-water disease challenge.

    PubMed

    Schubiger, Carla B; Orfe, Lisa H; Sudheesh, Ponnerassery S; Cain, Kenneth D; Shah, Devendra H; Call, Douglas R

    2015-01-01

    Flavobacterium psychrophilum causes bacterial cold-water disease in multiple fish species, including salmonids. An autochthonous Enterobacter strain (C6-6) inhibits the in vitro growth of F. psychrophilum, and when ingested as a putative probiotic, it provides protection against injection challenge with F. psychrophilum in rainbow trout. In this study, low-molecular-mass (≤3 kDa) fractions from both Enterobacter C6-6 and Escherichia coli K-12 culture supernatants inhibited the growth of F. psychrophilum. The ≤3-kDa fraction from Enterobacter C6-6 was analyzed by SDS-PAGE, and subsequent tandem mass spectroscopy identified EcnB, which is a small membrane lipoprotein that is a putative pore-forming toxin. Agar plate diffusion assays demonstrated that ecnAB knockout strains of both Enterobacter C6-6 and E. coli K-12 no longer inhibited F. psychrophilum (P < 0.001), while ecnAB-complemented knockout strains recovered the inhibitory phenotype (P < 0.001). In fish experiments, the engineered strains (C6-6 ΔecnAB and C6-6 ΔecnAB) and the wild-type strain (C6-6) were added to the fish diet every day for 38 days. On day 11, the fish were challenged by injection with a virulent strain of F. psychrophilum (CSF 259-93). Fish that were fed C6-6 had significantly longer survival than fish fed the ecnAB knockout strain (P < 0.0001), while fish fed the complemented knockout strain recovered the probiotic phenotype (P = 0.61). This entericidin is responsible for the probiotic activity of Enterobacter C6-6, and it may present new opportunities for therapeutic and prophylactic treatments against similarly susceptible pathogens. PMID:25381243

  4. Activity of Plazomicin (ACHN-490) against MDR clinical isolates of Klebsiella pneumoniae, Escherichia coli, and Enterobacter spp. from Athens, Greece

    PubMed Central

    Galani, Irene; Souli, Maria; Daikos, George L; Chrysouli, Zoi; Poulakou, Garyphalia; Psichogiou, Mina; Panagea, Theofano; Argyropoulou, Athina; Stefanou, Ioanna; Plakias, George; Giamarellou, Helen; Petrikkos, George

    2012-01-01

    The in vitro activity of plazomicin was evaluated against 300 multidrug resistant (MDR) (carbapenemase and/or ESBL-producing) isolates from four hospitals in Athens, an area where carbapenemase-producing organisms are endemic. Most of the isolates were also resistant to the legacy aminoglycosides with the MIC50/MIC90 to tobramycin, amikacin and gentamicin being 32/>32, 32/>32 and 4/>8 μg/ml, respectively. ACHN-490 retained activity (MICs⩽4 μg/ml) against all isolates of Klebsiella pneumoniae, Escherichia coli, and Enterobacter spp. tested with MIC50 and MIC90 of 1 and 2 μg/ml, respectively, irrespective of their MDR phenotype and it represents a promising alternative for the treatment of the most problematic Gram-negative pathogens. PMID:23040681

  5. Development of Multiple-Locus Variable-Number Tandem-Repeat Analysis for the Molecular Subtyping of Enterobacter sakazakii▿

    PubMed Central

    Mullane, N. R.; Ryan, M.; Iversen, C.; Murphy, M.; O'Gaora, P.; Quinn, T.; Whyte, P.; Wall, P. G.; Fanning, S.

    2008-01-01

    The genomic content of Enterobacter sakazakii strain ATCC BAA-894 was analyzed for variable-number tandem repeats (VNTRs). In this study we report the development of a multiple-locus VNTR analysis (MLVA) strategy for the subtyping of E. sakazakii. The method is based on a GeneScan analysis of four VNTR loci labeled with multiple fluorescent dyes. This approach was applied to a collection of 112 isolates representing all 16 of the currently defined E. sakazakii biogroups. MLVA successfully discriminated among these isolates and compared favorably with pulsed-field gel electrophoresis. The method was relatively fast and easy to perform. The potential value of MLVA as an epidemiological tool is discussed. PMID:18083860

  6. Evaluation of yeast dietary supplementation in broilers challenged or not with Salmonella on growth performance, cecal microbiota composition and Salmonella in ceca, cloacae and carcass skin.

    PubMed

    Mountzouris, K C; Dalaka, E; Palamidi, I; Paraskeuas, V; Demey, V; Theodoropoulos, G; Fegeros, K

    2015-10-01

    The dietary supplementation of Saccharomyces cerevisiae var. boulardii was evaluated in broilers challenged or not challenged with Salmonella Enteritidis (SE) using a 2 × 2 factorial arrangement. Depending on yeast inclusion at 0 (C) or 1 × 10⁹ cfu/kg diet (Y) and SE challenge (0 or log 6.3 cfu/bird) on d 15, the experiment had four treatments C, Y, C-SE, and Y-SE, respectively. Each treatment had seven replicate floor pens with 15 broilers. Growth performance responses were determined weekly and overall for the 5 week experimental period. Salmonella levels and prevalence in ceca, cloacae, and carcass skin were determined by culture procedures, while cecal microbiota was determined by real time PCR. Yeast supplementation had no effect (PY > 0.05) on growth performance. For the overall post SE-challenge period (i.e., wk 3 to wk 5), Salmonella reduced body weight gain (BWG) (PSE < 0.001), feed intake (FI) (PSE = 0.032), and the European production efficiency (EPEF) factor (PSE = 0.005). Broilers Y-SE had higher (P < 0.001) overall BW gain compared to C-SE ones. Overall mortality was 2.14% and did not differ (P > 0.05) between treatments. Reduced Salmonella levels in the cloacae (P = 0.014) and on the breast skin (P = 0.006) and lower prevalence on the neck skin (P = 0.007) were noted for treatment Y-SE compared to C-SE. Yeast supplementation did not have an effect (P > 0.05) on cecal microbiota composition at d 1 and d 21 post SE-challenge. On the contrary, SE-challenge reduced cecal levels of total bacteria (PSE = 0.002), E. coli (PSE = 0.006), Bifidobacterium spp. (PSE = 0.006), Bacteroides spp. (PSE = 0.010), and Clostridial populations belonging to cluster I and cluster XIVa, (PSE = 0.047 and PSE = 0.001, respectively) on d 1 post SE-challenge. At 21 d post SE-challenge, only the levels of cecal Lactobacillus spp. (PSE = 0.001) and Bifidobacterium spp. (PSE = 0.049) were reduced compared to the non SE-challenged groups. In conclusion, yeast supplementation in

  7. Antibacterial activity of Alpinia galanga (L) Willd crude extracts.

    PubMed

    Rao, Kiranmayee; Ch, Bhuvaneswari; Narasu, Lakshmi M; Giri, Archana

    2010-10-01

    Methanol, acetone and diethyl ether extracts of Alpinia galanga have been evaluated against pathogens viz. Bacillus subtilis MTCC 2391, Enterobacter aerogene, Enterobacter cloacae, Enterococcus faecalis, Escherichia coli MTCC 1563, Klebsiella pneumoniae, Pseudomonas aeruginosa MTCC 6642, Salmonella typhimurium, Staphylococcus aureus and Streptococcus epidermis using Agar well diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of all the extracts were determined using the macrodilution method. Methanol extracts have shown excellent activity towards all the pathogens with MIC and MBC values ranging from 0.04-1.28 mg/ml and 0.08-2.56 mg/ml, respectively. The GC-MS analysis of methanol extracts have yielded compounds like 5-hydroxymethyl furfural (59.9%), benzyl alcohol (57.6%), 1,8 cineole (15.65%), methylcinnamate (9.4%), 3-phenyl-2-butanone (8.5%) and 1,2 benzenedicarboxylic acid (8.9%), which could be responsible for its broad spectrum activity. So, A. galanga can be quite resourceful for the development of new generation drugs. PMID:20387130

  8. Extended-spectrum beta-lactamases among Enterobacteriaceae isolated in a public hospital in Brazil.

    PubMed

    Dropa, Milena; Balsalobre, Livia C; Lincopan, Nilton; Mamizuka, Elsa M; Murakami, Thays; Cassettari, Valéria C; Franco, Fábio; Guida, Stella M; Balabakis, Angelica J; Passadore, Lilian F; Santos, Silvia R; Matté, Glavur R; Matté, Maria H

    2009-01-01

    Extended-spectrum beta-lactamases (ESBL) in enterobacteria are recognized worldwide as a great hospital problem. In this study, 127 ESBL-producing Enterobacteriaceae isolated in one year from inpatients and outpatients at a public teaching hospital at São Paulo, Brazil, were submitted to analysis by PCR with specific primers for bla SHV, bla TEM and bla CTX-M genes. From the 127 isolates, 96 (75.6%) Klebsiella pneumoniae, 12 (9.3%) Escherichia coli, 8 (6.2%) Morganella morganii, 3 (2.3%) Proteus mirabilis, 2 (1.6%) Klebsiella oxytoca, 2 (1.6%) Providencia rettgeri, 2 (1.6%) Providencia stuartti, 1 (0.8%) Enterobacter aerogenes and 1 (0.8%) Enterobacter cloacae were identified as ESBL producers. Bla SHV, bla TEM and bla CTX-M were detected in 63%, 17.3% and 33.9% strains, respectively. Pulsed field gel eletrophoresis genotyping of K. pneumoniae revealed four main molecular patterns and 29 unrelated profiles. PCR results showed a high variety of ESBL groups among strains, in nine different species. The results suggest the spread of resistance genes among genetically different strains of ESBL-producing K. pneumoniae in some hospital wards, and also that some strongly related strains were identified in different hospital wards, suggesting clonal spread in the institutional environment. PMID:19739000

  9. Molecular epidemiology of KPC-2-producing Enterobacteriaceae (non-Klebsiella pneumoniae) isolated from Brazil.

    PubMed

    Tavares, Carolina Padilha; Pereira, Polyana Silva; Marques, Elizabeth de Andrade; Faria, Celio; de Souza, Maria da Penha Araújo Herkenhoff; de Almeida, Robmary; Alves, Carlene de Fátima Morais; Asensi, Marise Dutra; Carvalho-Assef, Ana Paula D'Alincourt

    2015-08-01

    In Brazil, since 2009, there has been an ever increasing widespread of the bla(KPC-2) gene, mainly in Klebsiella pneumoniae. This study aims to assess the molecular epidemiology and genetic background of this gene in Enterobacteriaceae (non-K. pneumoniae) species from 9 Brazilian states between 2009 and 2011. Three hundred eighty-seven isolates were analyzed exhibiting nonsusceptibility to carbapenems, in which the bla(KPC-2) gene was detected in 21.4%. By disk diffusion and E-test, these isolates exhibited high rates of resistance to most of the antimicrobials tested, including tigecycline (45.6% nonsusceptible) and polymyxin B (16.5%), the most resistant species being Enterobacter aerogenes and Enterobacter cloacae. We found great clonal diversity and a variety of bla(KPC-2)-carrying plasmids, all of them exhibiting a partial Tn4401 structure. Therefore, this study demonstrates the dissemination of KPC-2 in 9 Enterobacteriaceae species, including species that were not previously described such as Pantoea agglomerans and Providencia stuartii. PMID:25935630

  10. Biological activities of Morus celtidifolia leaf extracts.

    PubMed

    Viveros-Valdez, Ezequiel; Oranday-Cárdenas, Azucena; Rivas-Morales, Catalina; Verde-Star, María Julia; Carranza-Rosales, Pilar

    2015-07-01

    The aims of this research were to examine the antibacterial, cytotoxic and antiradical/antioxidant activities of the organic extracts obtained from the leaves of the medicinal plant Morus celtidifolia (Family: Moraceae). To evaluate its antimicrobial properties, M. celtidifolia was tested against the bacteria of medical importance: Bacillus subtilis, Staphyloccocus aureus, Enterococcus faecalis, Escherichia coli, Enterobacter cloacae and Enterobacter aerogenes. Cytotoxic activity was assessed by using the brine shrimp (Artemia salina) lethality assay and also by toxicity screening against human cancer cell lines: MCF-7 (human breast adenocarcinoma) and HeLa (cervix adenocarcinoma). The free radical-scavenging activity was determined by the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) assay. Results revealed that the hexanic extract has antibacterial activity only against Gram positive strains, while the methanolic extract showed better cytotoxic and antioxidant activities than the non- polar extract with a median lethal dose (LD₅₀) of 125μg/ml, 90μg/ml and 75μg/ml against A. salina, MCF-7 and HeLa cells respectively, and median effective concentration (EC₅₀) of 152μg/ml on radical scavenging assay. This is the first study reporting the biological activities of leaves of Morus celtidifolia. PMID:26142508

  11. Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae Isolated from Vegetables Imported from the Dominican Republic, India, Thailand, and Vietnam

    PubMed Central

    Zurfluh, Katrin; Nüesch-Inderbinen, Magdalena; Morach, Marina; Zihler Berner, Annina; Hächler, Herbert

    2015-01-01

    To examine to what extent fresh vegetables imported into Switzerland represent carriers of extended-spectrum-β-lactamase (ESBL)-producing Enterobacteriaceae, 169 samples of different types of fresh vegetables imported into Switzerland from the Dominican Republic, India, Thailand, and Vietnam were analyzed. Overall, 25.4% of the vegetable samples yielded one or more ESBL-producing Enterobacteriaceae, 78.3% of which were multidrug resistant. Sixty isolates were obtained: Escherichia coli, 26; Klebsiella pneumoniae, 26; Enterobacter cloacae, 6; Enterobacter aerogenes, 1; and Cronobacter sakazakii, 1. We found 29 isolates producing CTX-M-15, 8 producing CTX-M-14, 7 producing CTX-M-55, 3 producing CTX-M-65, 1 each producing CTX-M-1, CTX-M-3, CTX-M-27, and CTX-M-63, 5 producing SHV-2, 3 producing SHV-12, and 1 producing SHV-2a. Four of the E. coli isolates belonged to epidemiologically important clones: CTX-M-15-producing B2:ST131 (1 isolate), D:ST405 (1 isolate), and D:ST38 (2 isolates). One of the D:ST38 isolates belonged to the extraintestinal enteroaggregative E. coli (EAEC) D:ST38 lineage. Two of the K. pneumoniae isolates belonged to the epidemic clones sequence type 15 (ST15) and ST147. The occurrence of antibiotic-resistant pathogenic and commensal Enterobacteriaceae in imported agricultural foodstuffs constitutes a source of ESBL genes and a concern for food safety. PMID:25724954

  12. Binding to histo-blood group antigen-expressing bacteria protects human norovirus from acute heat stress

    PubMed Central

    Li, Dan; Breiman, Adrien; le Pendu, Jacques; Uyttendaele, Mieke

    2015-01-01

    This study aims to investigate if histo-blood group antigen (HBGA) expressing bacteria have any protective role on human norovirus (NoV) from acute heat stress. Eleven bacterial strains were included, belonging to Escherichia coli, Enterobacter cloacae, Enterobacter aerogenes, Clostridium difficile, Bifidobacterium adolescentis, and B. longum. HBGA expression of the bacteria as well as binding of human NoV virus-like particles (VLPs, GI.1, and GII.4 strains) to the bacteria were detected by flow cytometry. NoV VLPs pre-incubated with HBGA expressing or non-HBGA expressing bacteria were heated and detected by both direct ELISA and porcine gastric mucin-binding assay. The NoV-binding abilities of the bacteria correlated well with their HBGA expression profiles. Two HBGA expressing E. coli (LMG8223 and LFMFP861, both GI.1 and GII.4 binders) and one non-HBGA expressing E. coli (ATCC8739, neither GI.1 nor GII.4 binder) were selected for the heat treatment test with NoV VLPs. Compared with the same cell numbers of non-HBGA expressing E. coli, the presence of HBGA-expressing E. coli could always maintain higher antigen integrity, as well as mucin-binding ability of NoV VLPs of both GI.1 and GII.4 after heat-treatment at 90°C for 2 min. These results indicate that HBGA-expressing bacteria may protect NoVs during the food processing treatments, thereby facilitating their transmission. PMID:26191052

  13. Prevalence of extended spectrum beta-lactamase production among uropathogens in south Mumbai and its antibiogram pattern

    PubMed Central

    Aruna, K.; Mobashshera, T.

    2012-01-01

    β-lactams are the most widely used group of antimicrobials. However, increasing resistance to these valuable drugs in uropathogens, mediated principally by β-lactamases, has become a major concern. The present study was undertaken to determine the prevalence of Extended Spectrum β-Lactamase (ESBL) producers in clinical isolates of urine specimens, collected from various healthcare centres across south Mumbai. A total of 195 gram negative urine isolates were identified as Pseudomonas aeruginosa (13), Proteus mirabilis (21), Klebsiella pneumoniae (29), Escherichia coli (96), Enterobacter aerogenes (1), Enterobacter cloacae (1), Enterococcus fecalis (1), Morganella morganii (1), Citrobacter diversus (16), Citrobacter amalonaticus (5) and Proteus vulgaris (11). Antimicrobial Susceptibility Testing (AST) by Kirby-Bauer method showed 43.07 % (84/195) of the isolates were resistant to more than 70 % of the antibiotics used. Confirmatory screening using a combination of Double Disk Synergy Test (DDST), Phenotypic Confirmatory Disc Diffusion Test (PCDDT) and E-test revealed the overall prevalence of ESBL producers to be 34.71 % (68/195). The study showed 72.05 % of the ESBL producers to be resistant to fluoroquinolones, highlighting its extensive use in the region of south Mumbai. All ESBL producers were found to be sensitive to Imipenem whereas 82.36 % showed susceptibility to Amikacin making these 2 antibiotics the most effective choice of drug against ESBLs. In order to ensure rational treatment of highly resistant pathogens, the occurrence of ESBL and its primary studies may serve as a base for further research and findings.

  14. Comparison of two chromogenic media and evaluation of two molecular based identification systems for Enterobacter sakazakii detection

    PubMed Central

    Lehner, Angelika; Nitzsche, Sabine; Breeuwer, Pieter; Diep, Benjamin; Thelen, Karin; Stephan, Roger

    2006-01-01

    Background Enterobacter sakazakii is a foodborne pathogen that has been associated with sporadic cases and outbreaks causing meningitis, necrotizing enterocolitis and sepsis especially in neonates. The current FDA detection method includes two enrichment steps, the subculturing of the second enrichment broth on a selective agar (VRBG), a further subculturing of selected grown colonies on TSA and the subsequent biochemical identification of yellow-pigmented colonies by API20E. However, there is a strong need for simplified methods for isolation and identification of E. sakazakii. In this study, two chromogenic media, which allow to indicate presumptive E. sakazakii colonies by the alpha glucosidase activity, as well as a newly developed 1,6-alpha-glucosidase based conventional PCR assay and a rRNA oligonucleotide probe based commercial test system for identification of presumptive E. sakazakii were evaluated on 98 target and non-target strains. The methods were compared with respect to specificity aspects. Results A total of 75 presumptive E. sakazakii and 23 non-target strains were analysed by using chromogenic media, alpha-glucosidase based PCR assay, and the VIT assay. For most presumptive E. sakazakii strains on the chromogenic media, the PCR and VIT assay confirmed the identification. However, for a number of presumptive E. sakazakii isolates from fruit powder, the alpha-glucosidase PCR and VIT assay did not correspond to the typical E. sakazakii colonies on DFI and ESIA. Further characterization by API32E identification, phylogenetic analysis of partial 16S rRNA sequences and ribotyping strongly suggested, that these strains did not belong to the species E. sakazakii. The newly developed alpha-glucosidase based PCR assay as well as the commercially available VIT Enterobacter sakazakii identification test showed an excellent correlation with the 16S rRNA data, and are thus well suited for identification of E. sakazakii. Conclusion The results indicate that

  15. Cloning and Sequencing of the ompA Gene of Enterobacter sakazakii and Development of an ompA-Targeted PCR for Rapid Detection of Enterobacter sakazakii in Infant Formula

    PubMed Central

    Mohan Nair, Manoj Kumar; Venkitanarayanan, Kumar S.

    2006-01-01

    Enterobacter sakazakii is an emerging, infant formula-borne pathogen that causes severe meningitis, meningoencephalitis, sepsis, and necrotizing enterocolitis in neonates and infants, with a high fatality rate. Traditional detection methods take up to 7 days to identify E. sakazakii. The outer membrane protein A gene (ompA), along with its flanking sequences from E. sakazakii (ATCC 51329), was cloned in the pGEM-T Easy vector and sequenced. Comparison of the nucleotide and deduced amino acid sequences of the ompA gene with other sequences available in the GenBank database revealed a high degree of homology with ompA genes of other gram-negative bacteria belonging to the Enterobacteriaceae. Based on regions of the ompA gene unique to E. sakazakii, two primers were synthesized to develop and optimize an E. sakazakii-specific PCR. The PCR amplified a 469-bp DNA product from all E. sakazakii strains tested but not from other bacteria. Experiments to determine the sensitivity of the PCR indicated that it could detect as few as 103 CFU/ml of E. sakazakii bacteria in infant formula directly and 10−1 CFU/ml after an 8-h enrichment step. We conclude that this PCR, combined with enrichment culturing, has the potential to be used as a rapid tool for detecting the presence of E. sakazakii in infant formula. PMID:16597955

  16. Enhancement of the catalytic activity of ferulic acid decarboxylase from Enterobacter sp. Px6-4 through random and site-directed mutagenesis.

    PubMed

    Lee, Hyunji; Park, Jiyoung; Jung, Chaewon; Han, Dongfei; Seo, Jiyoung; Ahn, Joong-Hoon; Chong, Youhoon; Hur, Hor-Gil

    2015-11-01

    The enzyme ferulic acid decarboxylase (FADase) from Enterobacter sp. Px6-4 catalyzes the decarboxylation reaction of lignin monomers and phenolic compounds such as p-coumaric acid, caffeic acid, and ferulic acid into their corresponding 4-vinyl derivatives, that is, 4-vinylphenol, 4-vinylcatechol, and 4-vinylguaiacol, respectively. Among various ferulic acid decarboxylase enzymes, we chose the FADase from Enterobacter sp. Px6-4, whose crystal structure is known, and produced mutants to enhance its catalytic activity by random and site-directed mutagenesis. After three rounds of sequential mutations, FADase(F95L/D112N/V151I) showed approximately 34-fold higher catalytic activity than wild-type for the production of 4-vinylguaiacol from ferulic acid. Docking analyses suggested that the increased activity of FADase(F95L/D112N/V151I) could be due to formation of compact active site compared with that of the wild-type FADase. Considering the amount of phenolic compounds such as lignin monomers in the biomass components, successfully bioengineered FADase(F95L/D112N/V151I) from Enterobacter sp. Px6-4 could provide an ecofriendly biocatalytic tool for producing diverse styrene derivatives from biomass. PMID:26059194

  17. A robotic DNA purification protocol and real-time PCR for the detection of Enterobacter sakazakii in powdered infant formulae

    PubMed Central

    Derzelle, Sylviane; Dilasser, Françoise

    2006-01-01

    Background Enterobacter sakazakii is the causative agent of rare but severe food-borne infections associated with meningitis, necrotizing enterocolitis and sepsis in infants. Rehydrated powdered infant formulae have been implicated as the source of infection in several outbreaks and sporadic cases. In this work, a real time fluorescence resonance energy transfer PCR assay incorporating an internal amplification control (IAC) was developed for the specific detection of E. sakazakii in foods. Performance of the assay, coupled to an automated DNA extraction system and the E. sakazakii ISO-IDF (TS 22964/RM 210) enrichment procedure, was evaluated on infant formulae and samples from production environment. Results The real-time PCR assay had 100% specificity as assessed using 35 E. sakazakii and 184 non-E. sakazakii strains. According to the E. sakazakii strains tested, the detection limits ranged from 5 to 25 genomic copies. Assays on pure cultures (including real-time PCR and DNA extraction) gave a sensitivity of about 102 to 103 CFU/ml. Out of 41 naturally contaminated infant formulae and environmental samples analysed for the presence of E. sakazakii, 23 were positive by real-time PCR and 22 by the conventional culture method, giving 97.5% concordance with the ISO-IDF reference method. Conclusion This method, combining specific real-time PCR, automated DNA extraction and ISO-IDF standard enrichments, provides a useful tool for rapid screening of E. sakazakii in food and environmental matrices. PMID:17166252

  18. Low-temperature-active and salt-tolerant β-mannanase from a newly isolated Enterobacter sp. strain N18.

    PubMed

    You, Jia; Liu, Jin-Feng; Yang, Shi-Zhong; Mu, Bo-Zhong

    2016-02-01

    A low-temperature-active and salt-tolerant β-mannanase produced by a novel mannanase-producer, Enterobacter sp. strain N18, was isolated, purified and then evaluated for its potential application as a gel-breaker in relation to viscosity reduction of guar-based hydraulic fracturing fluids used in oil field. The enzyme could lower the viscosity of guar gum solution by more than 95% within 10 min. The purified β-mannanase with molecular mass of 90 kDa displayed high activity in a broad range of pH and temperature: more than 70% of activity was retained in the pH range of 3.0-8.0 with the optimal pH 7.5, about 50% activity at 20°C with the optimal temperature 50°C. Furthermore, the enzyme retained >70% activity in the presence of 0.5-4.0 M NaCl. These properties implied that the enzyme from strain N18 had potential for serving as a gel-breaker for low temperature oil wells and other industrial fields, where chemical gel breakers were inactive due to low temperature. PMID:26168907

  19. Proteomic and biochemical basis for enhanced growth yield of Enterobacter sp. LCR1 on insoluble phosphate medium.

    PubMed

    Kumar, Arvind; Rai, Lal Chand

    2015-01-01

    Proteomics and biochemical analyses were used to unravel the basis for higher growth yield of Enterobacter sp. LCR1 on insoluble phosphate medium compared to soluble. Proteomic analysis using 2-DE, MALDI-TOF/MS and LC-MS revealed the involvement of nine proteins. Down-regulation of fructose bisphosphate aldolase with decreased concentrations of glucose-6-phosphate and fructose-6-phosphate indicated diminished glycolysis. However, up-regulation of phosphoglycerate mutase, increase in the activities of 6-phosphogluconate dehydratase, 2-keto-3-deoxy-6-phosphogluconate aldolase and 6-phosphogluconate dehydrogenase suggested induction of Entner-Doudoroff and pentose phosphate pathways. These pathways generate sufficient energy from gluconic acid, which is also used for biosynthesis as indicated by up-regulation of elongation factor Tu, elongation factor G and protein disulfide isomerase. Increased reactive oxygen species (ROS) formation resulting from organic acid oxidation leads to overexpressed manganese superoxide dismutase and increased activities of catalase and ascorbate peroxidase. Thus the organism uses gluconate instead of glucose for energy, while alleviating extra ROS formation by oxidative defense enzymes. PMID:25053519

  20. Enterobacter asburiae strain L1: complete genome and whole genome optical mapping analysis of a quorum sensing bacterium.

    PubMed

    Lau, Yin Yin; Yin, Wai-Fong; Chan, Kok-Gan

    2014-01-01

    Enterobacter asburiae L1 is a quorum sensing bacterium isolated from lettuce leaves. In this study, for the first time, the complete genome of E. asburiae L1 was sequenced using the single molecule real time sequencer (PacBio RSII) and the whole genome sequence was verified by using optical genome mapping (OpGen) technology. In our previous study, E. asburiae L1 has been reported to produce AHLs, suggesting the possibility of virulence factor regulation which is quorum sensing dependent. This evoked our interest to study the genome of this bacterium and here we present the complete genome of E. asburiae L1, which carries the virulence factor gene virK, the N-acyl homoserine lactone-based QS transcriptional regulator gene luxR and the N-acyl homoserine lactone synthase gene which we firstly named easI. The availability of the whole genome sequence of E. asburiae L1 will pave the way for the study of the QS-mediated gene expression in this bacterium. Hence, the importance and functions of these signaling molecules can be further studied in the hope of elucidating the mechanisms of QS-regulation in E. asburiae. To the best of our knowledge, this is the first documentation of both a complete genome sequence and the establishment of the molecular basis of QS properties of E. asburiae. PMID:25196111

  1. Sulfonamide inhibition studies of the β-carbonic anhydrase from the newly discovered bacterium Enterobacter sp. B13.

    PubMed

    Eminoğlu, Ayşenur; Vullo, Daniela; Aşık, Aycan; Çolak, Dilşat Nigar; Çanakçı, Sabriye; Beldüz, Ali Osman; Supuran, Claudiu T

    2016-04-01

    The genome of the newly identified bacterium Enterobacter sp. B13 encodes for a β-class carbonic anhydrases (CAs, EC 4.2.1.1), EspCA. This enzyme was recently cloned, and characterized kinetically by this group (J. Enzyme Inhib. Med. Chem. 2016, 31). Here we report an inhibition study with sulfonamides and sulfamates of this enzyme. The best EspCA inhibitors were some sulfanylated sulfonamides with elongated molecules, metanilamide, 4-aminoalkyl-benzenesulfonamides, acetazolamide, and deacetylated methazolamide (KIs in the range of 58.7-96.5nM). Clinically used agents such as methazolamide, ethoxzolamide, dorzolamide, brinzolamide, benzolamide, zonisamide, sulthiame, sulpiride, topiramate and valdecoxib were slightly less effective inhibitors (KIs in the range of 103-138nM). Saccharin, celecoxib, dichlorophenamide and many simple benzenesulfonamides were even less effective as EspCA inhibitors, with KIs in the range of 384-938nM. Identification of effective inhibitors of this bacterial enzyme may lead to pharmacological tools useful for understanding the physiological role(s) of the β-class CAs in bacterial pathogenicity/virulence. PMID:26920803

  2. Enterobacter asburiae Strain L1: Complete Genome and Whole Genome Optical Mapping Analysis of a Quorum Sensing Bacterium

    PubMed Central

    Lau, Yin Yin; Yin, Wai-Fong; Chan, Kok-Gan

    2014-01-01

    Enterobacter asburiae L1 is a quorum sensing bacterium isolated from lettuce leaves. In this study, for the first time, the complete genome of E. asburiae L1 was sequenced using the single molecule real time sequencer (PacBio RSII) and the whole genome sequence was verified by using optical genome mapping (OpGen) technology. In our previous study, E. asburiae L1 has been reported to produce AHLs, suggesting the possibility of virulence factor regulation which is quorum sensing dependent. This evoked our interest to study the genome of this bacterium and here we present the complete genome of E. asburiae L1, which carries the virulence factor gene virK, the N-acyl homoserine lactone-based QS transcriptional regulator gene luxR and the N-acyl homoserine lactone synthase gene which we firstly named easI. The availability of the whole genome sequence of E. asburiae L1 will pave the way for the study of the QS-mediated gene expression in this bacterium. Hence, the importance and functions of these signaling molecules can be further studied in the hope of elucidating the mechanisms of QS-regulation in E. asburiae. To the best of our knowledge, this is the first documentation of both a complete genome sequence and the establishment of the molecular basis of QS properties of E. asburiae. PMID:25196111

  3. Isolation and Identification Enterobacter asburiae from Consumed Powdered Infant Formula Milk (PIF) in the Neonatal Intensive Care Unit (NICU).

    PubMed

    Mardaneh, Jalal; Soltan Dallal, Mohammad Mehdi

    2016-01-01

    Enterobacter asburiae (E. asburiae) is a facultative anaerobic, non-spore-forming gram-negative rod-shaped bacterium belonging to the family of Enterobacteriaceae. It is an opportunistic pathogen that its strains are isolated from a variety of clinical and environmental specimens. Since powdered infant formula milk (PIF) is not a sterile product, it is an excellent medium for bacterial growth. The aim of this study was to isolate and identify E. asburiae from PIF in the neonatal intensive care unit (NICU) and determine antimicrobial susceptibility patterns of this bacterium. A total 125 PIF samples were purchased from drug stores between June 2011 to March 2012. E. asburiae was isolated according to FDA method. For final confirmation, biochemical tests embedded in the API-20E system were used. The drug susceptibility test was performed using the disc diffusion method according to CLSI recommendations. Out of the 125 PIF samples investigated, 2 (1.6%) samples were positive for E. asburiae. All isolated strains were uniformly susceptible to aztreonam, cefotaxim, amikacin, streptomycin, nalidixic acid, meropenem, tetracycline, ceftazidime, and colistin. Variable susceptibility was seen to the some antimicrobial agents tested. Each country should categorize its own designed guidelines for the preparation and handling of PIF adapted to the local environment. Moreover, the pathogenesis of the E. asburiae in infants hospitalized in NICU and other groups such as immunosuppressed patients and HIV infected individuals is uncertain and requires further study. PMID:26853289

  4. Effect of antimicrobial peptides on colistin-susceptible and colistin-resistant strains of Klebsiella pneumoniae and Enterobacter asburiae.

    PubMed

    Kádár, Béla; Kocsis, Béla; Kristof, Katalin; Tóth, Ákos; Szabó, Dóra

    2015-12-01

    In this study susceptibility to different antimicrobial peptides was investigated on colistin-susceptible and colistin-resistant identical pulsotype strains of KPC-2 producing Klebsiella pneumoniae ST258 as well as colistin-susceptible and colistin-resistant Enterobacter asburiae strains isolated from clinical samples. In our test, bacteria were exposed to 50 mg/ml lactoferrin, lysozyme and protamine - cationic antimicrobial peptides belonging to innate immune system and having structural similarity to polymyxins - in separate reactions. After 18 hours incubation of colonies were counted. 40% of colistin-resistant K. pneumoniae strains and 97% of colistin-susceptible counterpart strains were lysed by protamine whereas 87% and 100% colony forming unit decrease by lysozyme was seen, respectively. In the case of colistin-resistant E. asburiae strains 1 log10 cell count increase were observed after treatment with lysozyme and 1.56 log10 after lactoferrin exposure compared to the initial number whereas the colistin-susceptible showed no relevant cell count increase. Our findings suggest that acquired colistin-resistance in Enterobacteriaceae is associated with tolerance against antimicrobial peptides. PMID:26689883

  5. [Enterobacter agglomerans B1 producing beta-galactosidase with transglycosylation activity: screening, identification, fermentation conditions, and galacto-oligosaccharides synthesis].

    PubMed

    Lu, Lili; Xiao, Min; Xu, Xiaodong

    2008-01-01

    Galacto-oligosaccharides (GOS) are promising non-digestible oligosaccharides recognized as prebiotics. Commercial GOS containing galactose as subunit, are synthesized from lactose using the galactosyl-transferase activity of beta-galactosidase. A strain producing beta-galactosidase with transglycosylation activity was screened from the soil. Phenotypic analysis including morphology and physiology characteristics and 16S rDNA sequence analysis were carried out. Based on taxonomy results, the strain was identified as Enterobacter agglomerans B1. Medium and fermentation conditions were optimized by single factor and orthogonal experiments. The enzyme reached 9.7 U/mL in the medium (pH 7.5) containing 1% lactose, 1% yeast extract, and 0.5% peptone when cultured at 25 degrees C for 26 h. Effects of pH, temperature, lactose concentration, and reaction time on transgalactosylation by whole cells were studied. Yield of GOS reached 40.7% in 30% lactose (pH 7.5) at 50 degrees C for 12 h, as analyzed by HPLC and TLC. The results of an MS analysis showed that GOS were composed of di, tri-, and tetrasaccharides. PMID:18338574

  6. Interaction between plants and bacteria: glucosinolates and phyllospheric colonization of cruciferous vegetables by Enterobacter radicincitans DSM 16656.

    PubMed

    Schreiner, Monika; Krumbein, Angelika; Ruppel, Silke

    2009-01-01

    For determining interactive plant-bacterial effects between glucosinolates and phyllospheric colonization by a plant growth-promoting strain, Enterobacter radicincitans DSM 16656, in cruciferous vegetables, the extent of bacterial colonization was assessed in 5 cruciferous vegetables (Brassica juncea, Brassica campestris, Brassica oleracea var. capitata, Brassica rapa var. alboglabra, Nasturtium officinale) using a species-specific TaqMan probe and quantitative real-time PCR. Colonization ability of inoculated E. radicincitans in the phyllosphere of these species varied from inability to colonize B. rapa up to a very good colonization rate of B. campestris. In addition to morphological factors and other plant compounds, the colonization rate was affected by different individual aromatic and aliphatic glucosinolates and their concentration, revealing that both plant pathogens and plant growth-promoting bacteria were affected by glucosinolates in their colonization behavior. In contrast, after E. radicincitans inoculation neither the total nor the individual glucosinolate concentrations in the phyllosphere of the 5 cruciferous species were affected, indicating that the nonpathogenic E. radicincitans might cause only poor cell damage by metabolizing plant cell components and does not induce a plant defense response and thus subsequently an increased glucosinolate concentration in the phyllosphere. Moreover, E. radicincitans induced no stimulation of indole glucosinolate biosynthesis by additional bacterial auxin supply. PMID:19556746

  7. Structural Basis of Enzymatic Activity for the Ferulic Acid Decarboxylase (FADase) from Enterobacter sp. Px6-4

    PubMed Central

    Liang, Lianming; Sun, Yuna; Huang, Jingwen; Li, Xuemei; Cao, Yi; Meng, Zhaohui; Zhang, Ke-Qin

    2011-01-01

    Microbial ferulic acid decarboxylase (FADase) catalyzes the transformation of ferulic acid to 4-hydroxy-3-methoxystyrene (4-vinylguaiacol) via non-oxidative decarboxylation. Here we report the crystal structures of the Enterobacter sp. Px6-4 FADase and the enzyme in complex with substrate analogues. Our analyses revealed that FADase possessed a half-opened bottom β-barrel with the catalytic pocket located between the middle of the core β-barrel and the helical bottom. Its structure shared a high degree of similarity with members of the phenolic acid decarboxylase (PAD) superfamily. Structural analysis revealed that FADase catalyzed reactions by an “open-closed” mechanism involving a pocket of 8×8×15 Å dimension on the surface of the enzyme. The active pocket could directly contact the solvent and allow the substrate to enter when induced by substrate analogues. Site-directed mutagenesis showed that the E134A mutation decreased the enzyme activity by more than 60%, and Y21A and Y27A mutations abolished the enzyme activity completely. The combined structural and mutagenesis results suggest that during decarboxylation of ferulic acid by FADase, Trp25 and Tyr27 are required for the entering and proper orientation of the substrate while Glu134 and Asn23 participate in proton transfer. PMID:21283705

  8. Production of calcite nanocrystal by a urease-positive strain of enterobacter ludwigii and study of its structure by SEM.

    PubMed

    Ghashghaei, Sara; Emtiazi, Giti

    2013-10-01

    The present research aimed at evaluating the effects of urease enzyme and increasing pH on calcite nanocrystal formation. Unlike some researches, the results showed that CaCO3 precipitation is not a general phenomenon among the bacteria and if a bacterium has not this ability, it will not be able to produce calcite even with an increase in pH. All urease-positive bacteria had this ability, while only some urease-negative bacteria were able to produce calcite. Production and characterization of nanocrystals on precipitating medium were shown primarily by light microscopy and then confirmed by X-ray diffraction (XRD) analysis. Crystallite particle size was determined using Scherrer formula that was sub-100-nm in all samples. Based on qualitative and quantitative studies, strain C8 was selected as the best calcite-producing strain. Phylogenetic analysis indicated that this isolate has 99 % similarity with Enterobacter ludwigii. 16S rRNA sequence of isolate was deposited in GenBank with accession number JX666242. The morphology and exact composition of nanocrystalline particles were determined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). According to data obtained by SEM, we suggest that nanocrystals of CaCO3 adhere to bacteria and each other to form small aggregates and then complex crystalline networks to trap bacteria. Many holes are present in these crystalline networks that seem to be due to the aggregation of nanocrystals. PMID:23677144

  9. Complete genome sequence of Enterobacter sp. IIT-BT 08: A potential microbial strain for high rate hydrogen production

    PubMed Central

    Khanna, Namita; Ghosh, Ananta Kumar; Huntemann, Marcel; Deshpande, Shweta; Han, James; Chen, Amy; Kyrpides, Nikos; Mavrommatis, Kostas; Szeto, Ernest; Markowitz, Victor; Ivanova, Natalia; Pagani, Ioanna; Pati, Amrita; Pitluck, Sam; Nolan, Matt; Woyke, Tanja; Teshima, Hazuki; Chertkov, Olga; Daligault, Hajnalka; Davenport, Karen; Gu, Wei; Munk, Christine; Zhang, Xiaojing; Bruce, David; Detter, Chris; Xu, Yan; Quintana, Beverly; Reitenga, Krista; Kunde, Yulia; Green, Lance; Erkkila, Tracy; Han, Cliff; Brambilla, Evelyne-Marie; Lang, Elke; Klenk, Hans-Peter; Goodwin, Lynne; Chain, Patrick; Das, Debabrata

    2013-01-01

    Enterobacter sp. IIT-BT 08 belongs to Phylum: Proteobacteria, Class: Gammaproteobacteria, Order: Enterobacteriales, Family: Enterobacteriaceae. The organism was isolated from the leaves of a local plant near the Kharagpur railway station, Kharagpur, West Bengal, India. It has been extensively studied for fermentative hydrogen production because of its high hydrogen yield. For further enhancement of hydrogen production by strain development, complete genome sequence analysis was carried out. Sequence analysis revealed that the genome was linear, 4.67 Mbp long and had a GC content of 56.01%. The genome properties encode 4,393 protein-coding and 179 RNA genes. Additionally, a putative pathway of hydrogen production was suggested based on the presence of formate hydrogen lyase complex and other related genes identified in the genome. Thus, in the present study we describe the specific properties of the organism and the generation, annotation and analysis of its genome sequence as well as discuss the putative pathway of hydrogen production by this organism. PMID:24976892

  10. Comprehensive Approaches to Molecular Biomarker Discovery for Detection and Identification of Cronobacter spp. (Enterobacter sakazakii) and Salmonella spp. ▿

    PubMed Central

    Yan, Xianghe; Gurtler, Joshua; Fratamico, Pina; Hu, Jing; Gunther, Nereus W.; Juneja, Vijay; Huang, Lihan

    2011-01-01

    Cronobacter spp. (formerly Enterobacter sakazakii) and Salmonella spp. are increasingly implicated internationally as important microbiological contaminants in low-moisture food products, including powdered infant formula. Estimates indicate that 40 to 80% of infants infected with Cronobacter sakazakii and/or Salmonella in the United States may not survive the illness. A systematic approach, combining literature-based data mining, comparative genome analysis, and the direct sequencing of PCR products of specific biomarker genes, was used to construct an initial collection of genes to be targeted. These targeted genes, particularly genes encoding virulence factors and genes responsible for unique phenotypes, have the potential to function as biomarker genes for the identification and differentiation of Cronobacter spp. and Salmonella from other food-borne pathogens in low-moisture food products. In this paper, a total of 58 unique Salmonella gene clusters and 126 unique potential Cronobacter biomarkers and putative virulence factors were identified. A chitinase gene, a well-studied virulence factor in fungi, plants, and bacteria, was used to confirm this approach. We found that the chitinase gene has very low sequence variability and/or polymorphism among Cronobacter, Citrobacter, and Salmonella, while differing significantly in other food-borne pathogens, either by sequence blasting or experimental testing, including PCR amplification and direct sequencing. This computational analysis for Cronobacter and Salmonella biomarker identification and the preliminary laboratory studies are only a starting point; thus, PCR and array-based biomarker verification studies of these and other food-borne pathogens are currently being conducted. PMID:21239552

  11. Characterization of Exoelectrogenic Bacteria Enterobacter Strains Isolated from a Microbial Fuel Cell Exposed to Copper Shock Load

    PubMed Central

    Feng, Cuijie; Li, Jiangwei; Qin, Dan; Chen, Lixiang; Zhao, Feng; Chen, Shaohua; Hu, Hongbo; Yu, Chang-Ping

    2014-01-01

    Microorganisms capable of generating electricity in microbial fuel cells (MFCs) have gained increasing interest. Here fourteen exoelectrogenic bacterial strains were isolated from the anodic biofilm in an MFC before and after copper (Cu) shock load by Hungate roll-tube technique with solid ferric (III) oxide as an electron acceptor and acetate as an electron donor. Phylogenetic analysis of the 16S rRNA gene sequences revealed that they were all closely related to Enterobacter ludwigii DSM 16688T within the Enterobacteriaceae family, although these isolated bacteria showed slightly different morphology before and after Cu shock load. Two representative strains R2B1 (before Cu shock load) and B4B2 (after Cu shock load) were chosen for further analysis. B4B2 is resistant to 200 mg L−1 of Cu(II) while R2B1 is not, which indicated the potential selection of the Cu shock load. Raman analysis revealed that both R2B1 and B4B2 contained c-type cytochromes. Cyclic voltammetry measurements revealed that strain R2B1 had the capacity to transfer electrons to electrodes. The experimental results demonstrated that strain R2B1 was capable of utilizing a wide range of substrates, including Luria-Bertani (LB) broth, cellulose, acetate, citrate, glucose, sucrose, glycerol and lactose to generate electricity, with the highest current density of 440 mA·m−2 generated from LB-fed MFC. Further experiments indicated that the bacterial cell density had potential correlation with the current density. PMID:25412475

  12. Enterobacter sakazakii targets DC-SIGN to induce immunosuppressive responses in dendritic cells by modulating MAP kinases

    PubMed Central

    Mittal, Rahul; Bulgheresi, Silvia; Emami, Claudia; Prasadarao, Nemani V.

    2009-01-01

    Enterobacter sakazakii (ES) is an emerging pathogen that causes meningitis and necrotizing enterocolitis in infants. Dendritic cells (DCs) are professional phagocytic cells that play an essential role in host defense against invading pathogens, however, the interaction of ES with DCs is not known. Here, we demonstrate that ES targets DC-SIGN to survive in myeloid DCs for which outer membrane protein A (OmpA) expression in ES is critical, although it is not required for uptake. In addition, DC-SIGN expression was sufficient to cause a significant invasion by ES in HeLa cells and intestinal epithelial cells, which are normally not invaded by ES. OmpA+ ES prevented the maturation of DCs by triggering the production of high levels of IL-10 and TGF-β and by suppressing the activation of MAP kinases. Pretreatment of DCs with antibodies to IL-10 and TGF-β or of bacteria with anti-OmpA antibodies significantly enhanced the maturation markers on DCs. Furthermore, DCs pretreated with various inhibitors of MAP kinases prohibited the increased production of pro-inflammatory cytokines stimulated by LPS or OmpA− ES. LPS pretreatment followed by OmpA+ ES infection of DCs failed to induce maturation of DCs, indicating that OmpA+ ES renders the cells in immunosuppressive state to external stimuli. Similarly, OmpA+ ES infected DCs failed to present antigen to T cells as indicated by the inability of T cells to proliferate in mixed lymphocyte reaction. We conclude that ES interacts with DC-SIGN to subvert the host immune responses by disarming MAP kinase pathway in DCs. PMID:19846880

  13. Partial purification and characterization of an inducible indole-3-acetyl-L-aspartic acid hydrolase from Enterobacter agglomerans

    SciTech Connect

    Chou, Jyh-Ching |; Cohen, J.D.; Mulbry, W.W.

    1996-11-01

    Indole-3-acetyl-amino acid conjugate hydrolases are believed to be important in the regulation of indole-3-acetic acid (IAA) metabolism in plants and therefore have potential uses for the alteration of plant IAA metabolism. To isolate bacterial strains exhibiting significant indole-3-acetyl-aspartate (IAA-Asp) hydrolase activity, a sewage sludge inoculation was cultured under conditions in which IAA-Asp served as the sole source of carbon and nitrogen. One isolate, Enterobacter agglomerans, showed hydrolase activity inducible by IAA-L-Asp or N-acetyl-L-Asp but not by IAA, (NH{sub 4}){sub 2}SO{sub 4}, urea, or indoleacetamide. Among a total of 17 IAA conjugates tested as potential substrates, the enzyme had an exclusively high substrate specificity for IAA-L-Asp of 13.5 mM. The optimal pH for this enzyme was between 8.0 and 8.5. In extraction buffer containing 0.8 mM Mg{sup 2+} the hydrolase activity was inhibited to 80% by 1 mM dithiothreitol and to 60% by 1 mm CuSO{sub 4}; the activity was increased by 40% with 1mM MnSO{sub 4}. However, in extraction buffer with no trace elements, the hydrolase activity was inhibited to 50% by either 1 mM dithiothreitol or 1% Triton X-100 (Sigma). These results suggest that disulfide bonding might be essential for enzyme activity. Purification of the hydrolase by hydroxyapatite and TSK-phenyl (HP-Genenchem, South San Francisco, CA) preparative high-performance liquid chromatography yielded a major 45-kD polypeptide as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. 45 refs., 5 figs., 3 tabs.

  14. Effects of Preculturing Conditions on Lag Time and Specific Growth Rate of Enterobacter sakazakii in Reconstituted Powdered Infant Formula

    PubMed Central

    Kandhai, M. C.; Reij, M. W.; Grognou, C.; van Schothorst, M.; Gorris, L. G. M.; Zwietering, M. H.

    2006-01-01

    Enterobacter sakazakii can be present, although in low levels, in dry powdered infant formulae, and it has been linked to cases of meningitis in neonates, especially those born prematurely. In order to prevent illness, product contamination at manufacture and during preparation, as well as growth after reconstitution, must be minimized by appropriate control measures. In this publication, several determinants of the growth of E. sakazakii in reconstituted infant formula are reported. The following key growth parameters were determined: lag time, specific growth rate, and maximum population density. Cells were harvested at different phases of growth and spiked into powdered infant formula. After reconstitution in sterile water, E. sakazakii was able to grow at temperatures between 8 and 47°C. The estimated optimal growth temperature was 39.4°C, whereas the optimal specific growth rate was 2.31 h−1. The effect of temperature on the specific growth rate was described with two secondary growth models. The resulting minimum and maximum temperatures estimated with the secondary Rosso equation were 3.6°C and 47.6°C, respectively. The estimated lag time varied from 83.3 ± 18.7 h at 10°C to 1.73 ± 0.43 h at 37°C and could be described with the hyperbolic model and reciprocal square root relation. Cells harvested at different phases of growth did not exhibit significant differences in either specific growth rate or lag time. Strains did not have different lag times, and lag times were short given that the cells had spent several (3 to 10) days in dry powdered infant formula. The growth rates and lag times at various temperatures obtained in this study may help in calculations of the period for which reconstituted infant formula can be stored at a specific temperature without detrimental impact on health. PMID:16597976

  15. Sustained activity and spectrum of selected extended-spectrum beta-lactams (carbapenems and cefepime) against Enterobacter spp. and ESBL-producing Klebsiella spp.: report from the SENTRY antimicrobial surveillance program (USA, 1997-2000).

    PubMed

    Jones, Ronald N; Biedenbach, Douglas J; Gales, Ana C

    2003-01-01

    Enterobacter spp. and Klebsiella spp. are important clinical pathogens that frequently exhibit resistance to third-generation cephalosporins. In Enterobacter spp. strains, resistance is usually due to derepression of the Amp C locus, whereas plasmid-encoded extended-spectrum beta-lactamases (ESBLs) are primarily responsible for resistance in Klebsiella spp. Here we report the results from the SENTRY Antimicrobial Surveillance Program concerning the rates and trends of resistance to extended-spectrum beta-lactams and other antimicrobial agents in Enterobacter spp. and Klebsiella spp. isolated between 1997 and 2000 in participating hospitals in the United States. Among Enterobacter spp., resistance (MIC>or=32 mg/l) to aztreonam, ceftazidime and ceftriaxone ranged from 12.3 to 21.2% over the 4 years, whereas resistance in Klebsiella (MIC>or=2 mg/l) ranged from 5.9 to 6.8%. There was no trend toward increased resistance to these beta-lactam agents over the monitored period. Carbapenems (imipenem, meropenem) and cefepime had excellent activity against both ceftazidime-susceptible and -resistant Enterobacter spp. and Klebsiella spp. (>99% susceptible), although the minimum inhibitory concentration values of cefepime were higher in ceftazidime-resistant isolates compared with ceftazidime-susceptible isolates. Co-resistance to other antimicrobial agents was common in both tested genus groups. PMID:12507831

  16. Klebsiella aerogenes urease gene cluster: sequence of ureD and demonstration that four accessory genes (ureD, ureE, ureF, and ureG) are involved in nickel metallocenter biosynthesis.

    PubMed

    Lee, M H; Mulrooney, S B; Renner, M J; Markowicz, Y; Hausinger, R P

    1992-07-01

    The region located immediately upstream from the Klebsiella aerogenes urease structural genes was sequenced and shown to possess an open reading frame capable of encoding a 29.8-kDa peptide. Deletions were generated in this gene, denoted ureD, and in each of the genes (ureE, ureF, and ureG) located immediately downstream of the three structural genes. Transformation of the mutated plasmids into Escherichia coli resulted in high levels of urease expression, but the enzyme was inactive (deletions in ureD, ureF, or ureG) or only partially active (deletions in ureE). Ureases were purified from the recombinant cells and shown to be identical to control enzyme when analyzed by gel filtration chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis; however, in every case the activity levels correlated to nickel contents as analyzed by atomic absorption analysis. UreD, UreE, UreF, and UreG peptides were tentatively identified by gel electrophoretic comparison of mutant and control cell extracts, by in vivo expression of separately cloned genes, or by in vitro transcription-translation analyses; the assignments were confirmed for UreE and UreG by amino-terminal sequencing. The latter peptides (apparent M(r)s, 23,900 and 28,500) were present at high levels comparable to those of the urease subunits, whereas the amounts of UreF (apparent M(r), 27,000) and UreD (apparent M(r), 29,300) were greatly reduced, perhaps because of the lack of good ribosome binding sites in the regions upstream of these open reading frames. These results demonstrate that all four accessory genes are necessary for the functional incorporation of the urease metallocenter. PMID:1624427

  17. IAA Producing Enterobacter sp. I-3 as a Potent Bio-herbicide Candidate for Weed Control: A Special Reference with Lettuce Growth Inhibition.

    PubMed

    Park, Jae-Man; Radhakrishnan, Ramalingam; Kang, Sang-Mo; Lee, In-Jung

    2015-06-01

    Development of bio-herbicides is an emerging method to weed management in agricultural field. Very few studies were conducted on identification of microbial bio-herbicides to weed control. The present study was aimed to isolate and identify the effective bio-herbicide potential bacterium from soil and assess their role on plant growth inhibition. Three-hundred and one rhizobacteria were isolated from agriculture field soil samples collected from various parts of Republic of Korea. Two bacterial strains, I-4-5 and I-3 were significantly reduced the seedling growth of radish when compared to their controls. The highest rate of seedling growth inhibition was observed in I-3 bacterial isolate treatment in lettuce and radish. The mechanism of an effective bio-herbicide I-3 to plant growth inhibition was determined by analyzing IAA in their culture medium. IAA biosynthesis pathway of Enterobacter sp. I-3 was identified as tryptophan-dependent pathway and its production was increased due to addition of tryptophan in culture medium as quantified by using GC-MS SIM. In an in vitro study revealed that I-3 bacterial culture exudate combined with tryptophan significantly decreased leaf length, leaf width, root length and increased the number of lateral roots of lettuce. Indeed, the genomic DNA of I-3 bacterium was isolated and 16S rDNA was sequenced to find out the name of the bacterium. Based on phylogenetic analysis, I-3 isolate was identified and named into Enterobacter sp. I-3. The results of this study suggest that the utilization of Enterobacter sp. I-3 to crop field can be act as a potential bio-herbicide against weed growth. PMID:25805908

  18. Clonal Dissemination of OXA-370-Producing Klebsiella pneumoniae in Rio de Janeiro, Brazil

    PubMed Central

    Pereira, Polyana Silva; Borghi, Mirla; de Araújo, Carlos Felipe Machado; Aires, Caio Augusto Martins; Oliveira, Jane Cleide Ribeiro; Asensi, Marise Dutra

    2015-01-01

    Enzymes of the OXA-48 family have become some of the most important beta-lactamases in the world. A new OXA-48 variant (OXA-370) was first described for an Enterobacter hormaechei strain isolated in Rio Grande do Sul (southern region of Brazil) in 2013. Here we report detection of the blaOXA-370 gene in 24 isolates belonging to three Enterobacteriaceae species (22 Klebsiella pneumoniae isolates, 1 Enterobacter cloacae isolate, and 1 Enterobacter aerogenes isolate) collected from five hospitals in Rio de Janeiro, Brazil, in 2013 and 2014. The isolates showed a multidrug resistance profile, and 12.5% were resistant to polymyxin B. Besides blaOXA-370, no other carbapenemase genes were observed by PCR, whereas blaOXA-1 was found in all isolates and 22 isolates (91.6%) possessed blaCTX-M-15. Molecular typing of the K. pneumoniae isolates by pulsed-field gel electrophoresis (PFGE) showed the presence of two clonal groups, i.e., KpA (21 isolates) and KpB (1 isolate). KpA was characterized as sequence type 16 (ST16) and KpB as ST1041 by multilocus sequence typing (MLST). ST16 has been observed for KPC-producing K. pneumoniae in Rio de Janeiro. Plasmid analysis performed with six representative OXA-370-producing isolates showed plasmids harboring the blaOXA-370 gene in all strains, ranging from 25 kb to 150 kb. This study suggests that there is an urgent need to investigate the presence of OXA-370 and dissemination of the K. pneumoniae ST16 clone carrying this gene in Brazil. PMID:25987619

  19. Distribution of extended-spectrum β-lactamases, AmpC β-lactamases, and carbapenemases among Enterobacteriaceae isolates causing intra-abdominal infections in the Asia-Pacific region: results of the study for Monitoring Antimicrobial Resistance Trends (SMART).

    PubMed

    Sheng, Wang-Huei; Badal, Robert E; Hsueh, Po-Ren

    2013-07-01

    The increasing trend of β-lactam resistance among Enterobacteriaceae is a worldwide threat. Enterobacteriaceae isolates causing intra-abdominal infections (IAI) from the Study for Monitoring Antimicrobial Resistance Trends (SMART) collected in 2008 and 2009 from the Asia-Pacific region were investigated. Detection of extended-spectrum β-lactamases (ESBLs), AmpC β-lactamases, and carbapenemases was performed by multiplex PCR. A total of 699 Enterobacteriaceae isolates with positive genotypic results, included Escherichia coli (n = 443), Klebsiella pneumoniae (n = 187), Enterobacter cloacae (n = 45), Klebsiella oxytoca (n = 9), Citrobacter freundii (n = 5), Proteus mirabilis (n = 3), Enterobacter aerogenes (n = 2), Morganella morganii (n = 2), and one each of Enterobacter asburiae, Proteus vulgaris, and Providencia rettgeri were analyzed. Nearly 20% of these β-lactamase-producing Enterobacteriaceae isolates were from community-associated IAI. CTX-M (588 isolates, including 428 [72.8%] with CTX-M-15) was the most common ESBL, followed by SHV (n = 59) and TEM (n = 4). CMY (n = 110, including 102 [92.7%] with CMY-2) was the most common AmpC β-lactamase, followed by DHA (n = 46) and ACT/MIR (n = 40). NDM (n = 65, including 62 [95.4%] with NDM-1) was the most common carbapenemase, followed by IMP (n = 7) and OXA (n = 7). Isolates from hospital-associated IAI had more complicated β-lactamase combinations than isolates from the community. Carbapenemases were all exclusively detected in Enterobacteriaceae isolates from India, except that IMP β-lactamases were also detected in Philippines and Australia. CTX-M β-lactamases were the predominant ESBLs produced by Enterobacteriaceae causing IAI in the Asia-Pacific region. Emergence of CTX-M-15-, CMY-2-, and NDM-1-producing Enterobacteriaceae isolates is of major concern and highlights the need for further surveillance in this area. PMID:23587958

  20. Enterobacter sakazakii in dried infant formulas and milk kitchens of maternity wards in São Paulo, Brazil.

    PubMed

    Palcich, Gabriela; Gillio, Cintia de Moraes; Aragon-Alegro, Lina Casale; Pagotto, Franco J; Farber, Jeffrey M; Landgraf, Mariza; Destro, Maria Teresa

    2009-01-01

    This study was the first conducted in Brazil to evaluate the presence of Enterobacter sakazakii in milk-based powdered infant formula manufactured for infants 0 to 6 months of age and to examine the conditions of formula preparation and service in three hospitals in São Paulo State, Brazil. Samples of dried and rehydrated infant formula, environments of milk kitchens, water, bottles and nipples, utensils, and hands of personnel were analyzed, and E. sakazakii and Enterobacteriaceae populations were determined. All samples of powdered infant formula purchased at retail contained E. sakazakii at <0.3 [corrected] most probable number (MPN)/100 g. In hospital samples, E. sakazakii was found in one unopened formula can (0.3 MPN/100 g) and in the residue from one nursing bottle from hospital A. All other cans of formula from the same lot bought at a retail store contained E. sakazakii at <0.3 [corrected] MPN/100 g. The pathogen also was found in one cleaning sponge from hospital B. Enterobacteriaceae populations ranged from 10(1) to 10(5) CFU/g in cleaning aids and <5 CFU/g in all formula types (dry or rehydrated), except for the sample that contained E. sakazakii, which also was contaminated with Enterobacteriaceae at 5 CFU/g. E. sakazakii isolates were not genetically related. In an experiment in which rehydrated formula was used as the growth medium, the temperature was that of the neonatal intensive care unit (25 degrees C), and the incubation time was the average time that formula is left at room temperature while feeding the babies (up to 4 h), a 2-log increase in levels of E. sakazakii was found in the formula. Visual inspection of the facilities revealed that the hygienic conditions in the milk kitchens needed improvement. The length of time that formula is left at room temperature in the different hospitals while the babies in the neonatal intensive care unit are being fed (up to 4 h) may allow for the multiplication of E. sakazakii and thus may lead to an

  1. Characterization of Fe (III)-reducing enrichment culture and isolation of Fe (III)-reducing bacterium Enterobacter sp. L6 from marine sediment.

    PubMed

    Liu, Hongyan; Wang, Hongyu

    2016-07-01

    To enrich the Fe (III)-reducing bacteria, sludge from marine sediment was inoculated into the medium using Fe (OH)3 as the sole electron acceptor. Efficiency of Fe (III) reduction and composition of Fe (III)-reducing enrichment culture were analyzed. The results indicated that the Fe (III)-reducing enrichment culture with the dominant bacteria relating to Clostridium and Enterobacter sp. had high Fe (III) reduction of (2.73 ± 0.13) mmol/L-Fe (II). A new Fe (III)-reducing bacterium was isolated from the Fe (III)-reducing enrichment culture and identified as Enterobacter sp. L6 by 16S rRNA gene sequence analysis. The Fe (III)-reducing ability of strain L6 under different culture conditions was investigated. The results indicated that strain L6 had high Fe (III)-reducing activity using glucose and pyruvate as carbon sources. Strain L6 could reduce Fe (III) at the range of NaCl concentrations tested and had the highest Fe (III) reduction of (4.63 ± 0.27) mmol/L Fe (II) at the NaCl concentration of 4 g/L. This strain L6 could reduce Fe (III) with unique properties in adaptability to salt variation, which indicated that it can be used as a model organism to study Fe (III)-reducing activity isolated from marine environment. PMID:26896316

  2. Isolation and characterization of xanthan-degrading Enterobacter sp. nov. LB37 for reducing the viscosity of xanthan in petroleum industry.

    PubMed

    Chen, Xiaoyi; Wang, Mi; Yang, Fan; Tang, Wenzhu; Li, Xianzhen

    2014-05-01

    A Gram-negative, straight rod and facultative anaerobic bacterium was isolated from soil sample. It exhibits the phenotypic characteristics consistent with its classification in the genus Enterobacter. The isolate ferment glucose to acid and gas. Arginine dihydrolase, ornithin decarboxylase and gelatinase but not deoxyribonuclease was produced by this isolate. There was no hydrogen sulfide production. On the basis of the phenotypic data, together with phylogenetic analysis based on 16S rDNA gene sequences, this strain should represent a novel species of the genus Enterobacter and was designated as LB37. The strain LB37 could degrade xanthan molecules resulting in the rapid decrease of the viscosity of xanthan solution used in oil drilling process. Endoxanthanase activity was also detected in the culture supernatant. To our knowledge, it is the first report on the microbes being involved in the xanthan degradation for oil industry. The isolate LB37 would be useful for potential application in enhanced oil recovery and oil drilling field. PMID:24326911

  3. Exploitation of the Medfly Gut Microbiota for the Enhancement of Sterile Insect Technique: Use of Enterobacter sp. in Larval Diet-Based Probiotic Applications.

    PubMed

    Augustinos, Antonios A; Kyritsis, Georgios A; Papadopoulos, Nikos T; Abd-Alla, Adly M M; Cáceres, Carlos; Bourtzis, Kostas

    2015-01-01

    The Mediterranean fruit fly (medfly), Ceratitis capitata, is a pest of worldwide substantial economic importance, as well as a Tephritidae model for sterile insect technique (SIT) applications. The latter is partially due to the development and utilization of genetic sexing strains (GSS) for this species, such as the Vienna 8 strain, which is currently used in mass rearing facilities worldwide. Improving the performance of such a strain both in mass rearing facilities and in the field could significantly enhance the efficacy of SIT and reduce operational costs. Recent studies have suggested that the manipulation of gut symbionts can have a significant positive effect on the overall fitness of insect strains. We used culture-based approaches to isolate and characterize gut-associated bacterial species of the Vienna 8 strain under mass rearing conditions. We also exploited one of the isolated bacterial species, Enterobacter sp., as dietary supplement (probiotic) to the larval diet, and we assessed its effects on fitness parameters under the standard operating procedures used in SIT operational programs. Probiotic application of Enterobacter sp. resulted in improvement of both pupal and adult productivity, as well as reduced rearing duration, particularly for males, without affecting pupal weight, sex ratio, male mating competitiveness, flight ability and longevity under starvation. PMID:26325068

  4. Exploitation of the Medfly Gut Microbiota for the Enhancement of Sterile Insect Technique: Use of Enterobacter sp. in Larval Diet-Based Probiotic Applications

    PubMed Central

    Papadopoulos, Nikos T.; Abd-Alla, Adly M. M.; Cáceres, Carlos; Bourtzis, Kostas

    2015-01-01

    The Mediterranean fruit fly (medfly), Ceratitis capitata, is a pest of worldwide substantial economic importance, as well as a Tephritidae model for sterile insect technique (SIT) applications. The latter is partially due to the development and utilization of genetic sexing strains (GSS) for this species, such as the Vienna 8 strain, which is currently used in mass rearing facilities worldwide. Improving the performance of such a strain both in mass rearing facilities and in the field could significantly enhance the efficacy of SIT and reduce operational costs. Recent studies have suggested that the manipulation of gut symbionts can have a significant positive effect on the overall fitness of insect strains. We used culture-based approaches to isolate and characterize gut-associated bacterial species of the Vienna 8 strain under mass rearing conditions. We also exploited one of the isolated bacterial species, Enterobacter sp., as dietary supplement (probiotic) to the larval diet, and we assessed its effects on fitness parameters under the standard operating procedures used in SIT operational programs. Probiotic application of Enterobacter sp. resulted in improvement of both pupal and adult productivity, as well as reduced rearing duration, particularly for males, without affecting pupal weight, sex ratio, male mating competitiveness, flight ability and longevity under starvation. PMID:26325068

  5. Cronobacter (Enterobacter) sakazakii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cronobacter sakazakii has been identified as an infrequently isolated opportunistic pathogen. Over 120 cases of C. sakazakii-related illness have been reported and most reported cases are life-threatening infections. Many of these outbreaks have been linked the consumption of C. sakazakii-contamina...

  6. TRANSCONJUGATION BETWEEN BACTERIA IN THE DIGESTIVE TRACT OF THE CUTWORM PERIDROMA SAUCIA

    EPA Science Inventory

    Transconjugants arising from transfer of plasmid R388::Tn172l between donor and recipient strains of Enterobacter cloacae were detected in samples from the digestive tracts and fecal pellets of variegated cutworms (Peridroma saucia).

  7. Transconjugation between Bacteria in the Digestive Tract of the Cutworm Peridroma saucia.

    PubMed

    Armstrong, J L; Wood, N D; Porteous, L A

    1990-05-01

    Transconjugants arising from transfer of plasmid R388::Tn1721 between donor and recipient strains of Enterobacter cloacae were detected in samples from the digestive tracts and fecal pellets of variegated cutworms (Peridroma saucia). PMID:16348197

  8. Transconjugation between Bacteria in the Digestive Tract of the Cutworm Peridroma saucia

    PubMed Central

    Armstrong, John L.; Wood, Nathan D.; Porteous, L. Arlene

    1990-01-01

    Transconjugants arising from transfer of plasmid R388::Tn1721 between donor and recipient strains of Enterobacter cloacae were detected in samples from the digestive tracts and fecal pellets of variegated cutworms (Peridroma saucia). PMID:16348197

  9. INFLUENCE OF PHOSPHATE CORROSION CONTROL COMPOUNDS ON BACTERIAL GROWTH

    EPA Science Inventory

    The influence of two phosphate corrosion compounds on the growth and survival of coliform and other heterotrophic bacteria was investigated in laboratory, field, and model system studies. Growth of Citrobacter freundii, Enterobacter cloacae, and Klebsiella pneumoniae was not sign...

  10. Aerobic bacterial microflora of Broad-snouted caiman (Caiman latirostris) oral cavity and cloaca, originating from parque Zoológico Arruda Câmara, Paraíba, Brazil.

    PubMed

    Silva, J S A; Mota, R A; Pinheiro Júnior, J W; Almeida, M C S; Silva, D R; Ferreira, D R A; Azevedo, J C N

    2009-01-01

    The objective of this study was to isolate and identify the aerobic bacterial microflora from the oral cavity mucosa and cloaca's samples, collected from Broad-snouted caiman (Caiman latirostris), born and bred in captivity at Parque Zoológico Arruda Câmara, João Pessoa, Paraíba, Brazil. The most common bacteria were Staphylococcus sp. (14.74%), Corynebacterium sp. (13.68%), Escherichia coli (13.68%) and Shigella sp.(11.58%), and the less common were Citrobacter sp. (1.05%), Klebsiella pneumoniae (1.05%) and Salmonella sp. (1.05%).This emphasizes the importance of these microorganisms' participation in infectious processes (sepsis) and injuries caused by crocodilians. PMID:24031343

  11. Alleviation of Salt Stress by Enterobacter sp. EJ01 in Tomato and Arabidopsis Is Accompanied by Up-Regulation of Conserved Salinity Responsive Factors in Plants

    PubMed Central

    Kim, Kangmin; Jang, Ye-Jin; Lee, Sang-Myeong; Oh, Byung-Taek; Chae, Jong-Chan; Lee, Kui-Jae

    2014-01-01

    Microbiota in the niches of the rhizosphere zones can affect plant growth and responses to environmental stress conditions via mutualistic interactions with host plants. Specifically, some beneficial bacteria, collectively referred to as Plant Growth Promoting Rhizobacteria (PGPRs), increase plant biomass and innate immunity potential. Here, we report that Enterobacter sp. EJ01, a bacterium isolated from sea china pink (Dianthus japonicus thunb) in reclaimed land of Gyehwa-do in Korea, improved the vegetative growth and alleviated salt stress in tomato and Arabidopsis. EJ01 was capable of producing 1-aminocy-clopropane-1-carboxylate (ACC) deaminase and also exhibited indole-3-acetic acid (IAA) production. The isolate EJ01 conferred increases in fresh weight, dry weight, and plant height of tomato and Arabidopsis under both normal and high salinity conditions. At the molecular level, short-term treatment with EJ01 increased the expression of salt stress responsive genes such as DREB2b, RD29A, RD29B, and RAB18 in Arabidopsis. The expression of proline biosynthetic genes (i.e. P5CS1 and P5CS2) and of genes related to priming processes (i.e. MPK3 and MPK6) were also up-regulated. In addition, reactive oxygen species scavenging activities were enhanced in tomatoes treated with EJ01 in stressed conditions. GFP-tagged EJ01 displayed colonization in the rhizosphere and endosphere in the roots of Arabidopsis. In conclusion, the newly isolated Enterobacter sp. EJ01 is a likely PGPR and alleviates salt stress in host plants through multiple mechanisms, including the rapid up-regulation of conserved plant salt stress responsive signaling pathways. PMID:24598995

  12. Partial hydrolysis of dieldrin by aerobacter aerogenes

    USGS Publications Warehouse

    Wedemeyer, G.

    1968-01-01

    Although dieldrin (1 , 2, 3 , 4, 10, 10-hexachloro-6, 7-epoxy-1 ,4 ,4a ,5 ,6, 7,8, 8a-octahydro-1 ,4-endo, exo-5, 8-dirnethanonaphthalene) metabolism by mammals (F. Korte and H. Arent, Life Sci. 4:2017, 1965) and insects (D. F. Heath and M. Vanderkar, Brit. J. Ind. Med. 21:269, 1964) has been reported, little is known about the degradation of this important pesticide by microorganisms.

  13. The role of microorganisms in psoriasis.

    PubMed

    Noah, P W

    1990-12-01

    The microflora of 297 psoriasis patients was extensively examined. Throat, urine, and skin surfaces from scalp, ears, chest, face, axillary, submammary, umbilical, upper back, inguinal crease, gluteal-fold, perirectal, vaginal, pubis, penis, scrotal, leg, hands, feet, finger, and toenail areas were cultured for aerobic bacteria, yeast, and dermatophytes. Antibody levels to streptococcal enzymes were performed (streptolysin-O, DNAse-B, hyaluronidase, STREPTOZYME). Giemsa smears and KOH preparations were also used to determine yeast and dermatophyte presence. Associated organisms thought to provoke a psoriatic attack were as follows: streptococcal groups A, B, C, D, F, G, S viridans, S pneumoniae; Klebsiella pneumoniae, oxytoca; Escherichia coli; Enterobacter cloacae, E aerogenes, E agglomerans; Proteus mirabilis, P vulgaris; Citrobacter freundii, C diversus; Morganella morganii; Pseudomonas aeruginosa, P maltiphilia, P putida; Serratia marcescens; Acinetobacter calbio aceticus, A luoffi; Flavobacterium specie; CDC groups Ve-1, Ve-2, E-o2; Bacillus subtilis, cereus; Staphylococcus aureus; Candida albicans, C parapsilosis; Torulopsis, glabrata; Rhodotorula and dermatophytes. One or more antistreptococal enzyme tests was positive in 50% of patients. Titers to hepatitis E were elevated in one patient and to HIV in two patients. PMID:2285571

  14. Separation and confirmation of nine Enterobacteriaceae strains that carry the blaNDM-1 gene

    PubMed Central

    LI, TIAN-JIAO; LI, CHEN-XUE; CHENG, SHU-PING; WANG, XU-MING; FU, SHENG-MIAO; LI, XIAO-JUAN; HUANG, TAO; FU, HUI-QUN; LIN, SONG; LU, YE

    2015-01-01

    The aim of the present study was to confirm the existence of carbapenem-resistant Enterobacteriaceae carrying the blaNDM-1 gene in clinics in Hainan province, China. Collected clinical bacterial isolates that were Enterobacteriaceae strains suspected of producing carbapenemase were used as experimental strains. Drug resistance to imipenem, meropenem and other antibacterial agents was tested. Imipenem/imipenem inhibitor (IP/IPI) E-testing was conducted to identify the bacterial strains that produced metallo-β-lactamases. The blaNDM-1 drug resistance gene was amplified by polymerase chain reaction (PCR), and agarose gel electrophoresis (AGE) and sequencing were conducted to identify the products. The species of the strains carrying the blaNDM-1 gene were determined using a biochemical identification system. Through the IP/IPI E-test, 21 of the 30 collected Enterobacteriaceae strains were found to be positive, indicating that 70% of the strains produced metallo-β-lactamases. Following blaNDM-1 gene PCR amplification, AGE and sequencing tests confirmed that nine of the strains carried the blaNDM-1 drug resistance gene. The biochemical identification system indicated that four of the strains were Klebsiella pneumoniae, two were Escherichia coli, two were Enterobacter cloacae and one was Enterobacter aerogenes. Drug susceptibility testing in vitro demonstrated that the strains were 100% resistant to a broad spectrum antibiotic plus lactamase inhibitor, cephalosporins and carbapenems. However, they had high sensitivity rates to polymyxin B and tigecycline of 100 and 88.9%, respectively. The sensitivity rate to amikacin was also high at 77.8%, whereas sensitivity to ciprofloxacin and gentamicin was moderate at rates of 44.4 and 33.3% respectively. This clinical study of Enterobacteriaceae strains that carry the blaNDM-1 gene in Hainan shows a bacterial tolerance that is different from that in previous studies, which requires further in-depth study. PMID:25780416

  15. The tryptophan repressor sequence is highly conserved among the Enterobacteriaceae.

    PubMed Central

    Arvidson, D N; Arvidson, C G; Lawson, C L; Miner, J; Adams, C; Youderian, P

    1994-01-01

    Tryptophan biosynthesis in Escherichia coli is regulated by the product of the trpR gene, the tryptophan (Trp) repressor. Trp aporepressor binds the corepressor, L-tryptophan, to form a holorepressor complex, which binds trp operator DNA tightly, and inhibits transcription of the tryptophan biosynthetic operon. The conservation of trp operator sequences among enteric Gram-negative bacteria suggests that trpR genes from other bacterial species can be cloned by complementation in E. coli. To clone trpR homologues, a deletion of the E. coli trpR gene, delta trpR504, was made on a plasmid by site-directed mutagenesis, then crossed onto the E. coli genome. Plasmid clones of the trpR genes of Enterobacter aerogenes and Enterobacter cloacae were isolated by complementation of the delta trpR504 allele, scored as the ability to repress beta-galactosidase synthesis from a prophage-borne trpE-lacZ gene fusion. The predicted amino acid sequences of four enteric TrpR proteins show differences, clustered on the backside of the folded repressor, opposite the DNA-binding helix-turn-helix substructures. These differences are predicted to have little effect on the interactions of the aporepressor with tryptophan, holorepressor with operator DNA, or tandemly bound holorepressor dimers with one another. Although there is some variation observed at the dimer interface, interactions predicted to stabilize the interface are conserved. The phylogenetic relationships revealed by the TrpR amino acid sequence alignment agree with the results of others. PMID:8208606

  16. [Investigation of the presence of New Delhi metallo-beta-lactamase-1 (NDM-1) by PCR in carbapenem-resistant gram-negative isolates].

    PubMed

    Yanık, Keramettin; Emir, Dilek; Eroğlu, Cafer; Karadağ, Adil; Güney, Akif Koray; Günaydın, Murat

    2013-04-01

    Bacteria producing New Delhi metallo-beta-lactamase-1 (NDM-1) exhibit high level resistance to beta-lactams including carbapenems. This broad-spectrum resistance limits treatment options for infections caused by NDM-1 producers. NDM-1 was first isolated from an Indian patient in Sweden; since then, NDM-1 producing isolates have been identified in many countries including Turkey. In this study, we investigated the presence of NDM-1 by PCR method in various gram-negative isolates recovered from clinical specimens in tertiary care hospitals in Samsun, Turkey. A total of 210 carbapenem-resistant gram-negative isolates (132 Acinetobacter baumannii, 54 Pseudomonas aeruginosa, 5 Pseudomonas putida, 8 Enterobacter cloacae, 3 Enterobacter aerogenes, 3 Klebsiella pneumoniae, 2 Providencia rettgeri, 2 Escherichia coli and 1 Citrobacter freundii) were included in the study. Identification and antibiotic susceptibility testing of the isolates were performed by using Vitek-2 Compact (bioMerieux, France) and BD Phoenix (BD Diagnostic Systems, MD) automated systems. The results of antibiotic susceptibility testing were interpreted according to the CLSI recommendations. In our study, NDM-1 gene was not detected in any of the clinical isolates by PCR. There was only one case study that reported the presence of NDM-1 in clinical isolates from Turkey [Poirel L et al. Antimicrob Agents Chemother 2012;56:2784]. Our data, together with the others, indicated that the existence of NDM-1 in clinical isolates is not common in Turkey. However, since NDM-1 is a plasmid-encoded enzyme, there is always a risk of spread of this resistance through the bacterial strains in our country. Therefore, continuous surveillance and investigation of carbapenem-resistant isolates with resistance patterns suggestive of NDM-1 may enable to identify NDM-1 producing isolates. Meanwhile special care should be given on rational antibiotic use and establishment of appropriate infection control policies to prevent

  17. Cost-Effective and Rapid Presumptive Identification of Gram-Negative Bacilli in Routine Urine, Pus, and Stool Cultures: Evaluation of the Use of CHROMagar Orientation Medium in Conjunction with Simple Biochemical Tests

    PubMed Central

    Ohkusu, Kiyofumi

    2000-01-01

    The algorithm for a new identification system was designed on the basis of colony color and morphology on CHROMagar Orientation medium in conjunction with simple biochemical tests such as indole (IND), lysine decarboxylase (LDC), and ornithine decarboxylase (ODC) utilization tests with gram-negative bacilli isolated from urine samples as well as pus, stool, and other clinical specimens by the following colony characteristics, biochemical reactions, and serological results: pinkish to red, IND positive (IND+), Escherichia coli; metallic blue, IND+, LDC+, and ODC negative (ODC−), Klebsiella oxytoca; IND+, LDC−, and ODC+, Citrobacter diversus; IND+ or IND−, LDC−, and ODC−, Citrobacter freundii; IND−, LDC+, and ODC+, Enterobacter aerogenes; IND−, LDC−, and ODC+, Enterobacter cloacae; IND−, LDC+, and ODC−, Klebsiella pneumoniae; diffuse brown and IND+, Morganella morganii; IND−, Proteus mirabilis; aqua blue, Serratia marcescens; bluish green and IND+, Proteus vulgaris; transparent yellow-green, serology positive, Pseudomonas aeruginosa; clear and serology positive, Salmonella sp.; other colors and reactions, the organism was identified by the full identification methods. The accuracy and cost-effectiveness of this new system were prospectively evaluated. During an 8-month period, a total of 345 specimens yielded one or more gram-negative bacilli. A total of 472 gram-negative bacillus isolates were detected on CHROMagar Orientation medium. For 466 of the isolates (98.7%), no discrepancies in the results were obtained on the basis of the identification algorithm. The cost of identification of gram-negative bacilli during this period was reduced by about 70%. The results of this trial for the differentiation of the most commonly encountered gram-negative pathogens in clinical specimens with the new algorithm were favourable in that it permitted reliable detection and presumptive identification. In addition, this rapid identification system not only

  18. AmpC β-Lactamases

    PubMed Central

    Jacoby, George A.

    2009-01-01

    Summary: AmpC β-lactamases are clinically important cephalosporinases encoded on the chromosomes of many of the Enterobacteriaceae and a few other organisms, where they mediate resistance to cephalothin, cefazolin, cefoxitin, most penicillins, and β-lactamase inhibitor-β-lactam combinations. In many bacteria, AmpC enzymes are inducible and can be expressed at high levels by mutation. Overexpression confers resistance to broad-spectrum cephalosporins including cefotaxime, ceftazidime, and ceftriaxone and is a problem especially in infections due to Enterobacter aerogenes and Enterobacter cloacae, where an isolate initially susceptible to these agents may become resistant upon therapy. Transmissible plasmids have acquired genes for AmpC enzymes, which consequently can now appear in bacteria lacking or poorly expressing a chromosomal blaAmpC gene, such as Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. Resistance due to plasmid-mediated AmpC enzymes is less common than extended-spectrum β-lactamase production in most parts of the world but may be both harder to detect and broader in spectrum. AmpC enzymes encoded by both chromosomal and plasmid genes are also evolving to hydrolyze broad-spectrum cephalosporins more efficiently. Techniques to identify AmpC β-lactamase-producing isolates are available but are still evolving and are not yet optimized for the clinical laboratory, which probably now underestimates this resistance mechanism. Carbapenems can usually be used to treat infections due to AmpC-producing bacteria, but carbapenem resistance can arise in some organisms by mutations that reduce influx (outer membrane porin loss) or enhance efflux (efflux pump activation). PMID:19136439

  19. Rapid Identification of ESKAPE Bacterial Strains Using an Autonomous Microfluidic Device

    PubMed Central

    Ho, Jack Y.; Cira, Nate J.; Crooks, John A.; Baeza, Josue; Weibel, Douglas B.

    2012-01-01

    This article describes Bacteria ID Chips (‘BacChips’): an inexpensive, portable, and autonomous microfluidic platform for identifying pathogenic strains of bacteria. BacChips consist of a set of microchambers and channels molded in the elastomeric polymer, poly(dimethylsiloxane) (PDMS). Each microchamber is preloaded with mono-, di-, or trisaccharides and dried. Pressing the layer of PDMS into contact with a glass coverslip forms the device; the footprint of the device in this article is ∼6 cm2. After assembly, BacChips are degased under large negative pressure and are stored in vacuum-sealed plastic bags. To use the device, the bag is opened, a sample containing bacteria is introduced at the inlet of the device, and the degased PDMS draws the sample into the central channel and chambers. After the liquid at the inlet is consumed, air is drawn into the BacChip via the inlet and provides a physical barrier that separates the liquid samples in adjacent microchambers. A pH indicator is admixed with the samples prior to their loading, enabling the metabolism of the dissolved saccharides in the microchambers to be visualized. Importantly, BacChips operate without external equipment or instruments. By visually detecting the growth of bacteria using ambient light after ∼4 h, we demonstrate that BacChips with ten microchambers containing different saccharides can reproducibly detect the ESKAPE panel of pathogens, including strains of: Enterococcus faecalis, Enteroccocus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter aerogenes, and Enterobacter cloacae. This article describes a BacChip for point-of-care detection of ESKAPE pathogens and a starting point for designing multiplexed assays that identify bacterial strains from clinical samples and simultaneously determine their susceptibility to antibiotics. PMID:22848451

  20. Detection of extended-spectrum beta-lactamases among Enterobacteriaceae by use of semiautomated microbiology systems and manual detection procedures.

    PubMed

    Wiegand, Irith; Geiss, Heinrich K; Mack, Dietrich; Stürenburg, Enno; Seifert, Harald

    2007-04-01

    Three commercially available microbiology identification and susceptibility testing systems were compared with regard to their ability to detect extended-spectrum beta-lactamase (ESBL) production in Enterobacteriaceae, i.e., the Phoenix Automated Microbiology System (BD Diagnostic Systems, Sparks, MD), the VITEK 2 System (bioMérieux, Marcy l'Etoile, France), and the MicroScan WalkAway-96 System (Dade Behring, Inc., West Sacramento, CA), using routine testing panels. One hundred fifty putative ESBL producers were distributed blindly to three participating laboratories. Conventional phenotypic confirmatory tests such as the disk approximation method, the CLSI double-disk synergy test, and the Etest ESBL were also evaluated. Biochemical and molecular characterization of beta-lactamases performed at an independent laboratory was used as the reference method. One hundred forty-seven isolates of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Enterobacter aerogenes, Citrobacter freundii, Serratia marcescens, Proteus mirabilis, Proteus vulgaris, and Morganella morganii were investigated. Of these isolates, 85 were identified as ESBL producers by the reference method. The remaining isolates were identified as non-ESBL producers; they were either hyperproducers of their chromosomal AmpC, Koxy, or SHV enzymes or lacked any detectable beta-lactamase activity. The system with the highest sensitivity for the detection of ESBLs was the Phoenix (99%), followed by the VITEK 2 (86%) and the MicroScan (84%); however, specificity was more variable, ranging from 52% (Phoenix) to 78% (VITEK 2). The performance of the semiautomated systems differed widely with the species investigated. The sensitivities of the conventional test methods ranged from 93 to 94%. The double-disk synergy test showed the highest specificity and positive predictive value among all test methods, i.e., 97% and 98%, respectively. PMID:17287329

  1. Isolation of high-salinity-tolerant bacterial strains, Enterobacter sp., Serratia sp., Yersinia sp., for nitrification and aerobic denitrification under cyanogenic conditions.

    PubMed

    Mpongwana, N; Ntwampe, S K O; Mekuto, L; Akinpelu, E A; Dyantyi, S; Mpentshu, Y

    2016-01-01

    Cyanides (CN(-)) and soluble salts could potentially inhibit biological processes in wastewater treatment plants (WWTPs), such as nitrification and denitrification. Cyanide in wastewater can alter metabolic functions of microbial populations in WWTPs, thus significantly inhibiting nitrifier and denitrifier metabolic processes, rendering the water treatment processes ineffective. In this study, bacterial isolates that are tolerant to high salinity conditions, which are capable of nitrification and aerobic denitrification under cyanogenic conditions, were isolated from a poultry slaughterhouse effluent. Three of the bacterial isolates were found to be able to oxidise NH(4)-N in the presence of 65.91 mg/L of free cyanide (CN(-)) under saline conditions, i.e. 4.5% (w/v) NaCl. The isolates I, H and G, were identified as Enterobacter sp., Yersinia sp. and Serratia sp., respectively. Results showed that 81% (I), 71% (G) and 75% (H) of 400 mg/L NH(4)-N was biodegraded (nitrification) within 72 h, with the rates of biodegradation being suitably described by first order reactions, with rate constants being: 4.19 h(-1) (I), 4.21 h(-1) (H) and 3.79 h(-1) (G), respectively, with correlation coefficients ranging between 0.82 and 0.89. Chemical oxygen demand (COD) removal rates were 38% (I), 42% (H) and 48% (G), over a period of 168 h with COD reduction being highest at near neutral pH. PMID:27148718

  2. 2-ketogluconic acid secretion by incorporation of Pseudomonas putida KT 2440 gluconate dehydrogenase (gad) operon in Enterobacter asburiae PSI3 improves mineral phosphate solubilization.

    PubMed

    Kumar, Chanchal; Yadav, Kavita; Archana, G; Naresh Kumar, G

    2013-09-01

    Enterobacter asburiae PSI3 is known to efficiently solubilize rock phosphate by secretion of approximately 50 mM gluconic acid in Tris-buffered medium in the presence of 75 mM glucose and in a mixture of seven aldosugars each at 15 mM concentration, mimicking alkaline vertisol soils. Efficacy of this bacterium in the rhizosphere requires P release in the presence of low amount of sugars. To achieve this, E. asburiae PSI3 has been manipulated to express gluconate dehydrogenase (gad) operon of Pseudomonas putida KT 2440 to produce 2-ketogluconic acid. E. asburiae PSI3 harboring gad operon had 438 U of GAD activity, secreted 11.63 mM 2-ketogluconic and 21.65 mM gluconic acids in Tris-rock phosphate-buffered medium containing 45 mM glucose. E. asburiae PSI3 gad transformant solubilized 0.84 mM P from rock phosphate in TRP-buffered liquid medium. In the presence of a mixture of seven sugars each at 12 mM, the transformant brought about a drop in pH to 4.1 and released 0.53 mM P. PMID:23666029

  3. Degradation of acephate by Enterobacter asburiae, Bacillus cereus and Pantoea agglomerans isolated from diamondback moth Plutella xylostella (L), a pest of cruciferous crops.

    PubMed

    Ramya, Shanivarsanthe Leelesh; Venkatesan, Thiruvengadam; Murthy, Kottilingam Srinivasa; Jalali, Sushil Kumar; Varghese, Abraham

    2016-07-01

    Acephate-degrading bacterial isolates were isolated from the larval gut of diamondback moth Plutella xylostella, a notorious pest of cruciferous crops worldwide that has developed resistance to insecticides. Partial 16S rRNA gene sequencing identified the isolates as Bacillus cereus (PX-B.C.Or), Enterobacter asburiae (PXE), and Pantoae agglomerans (PX-Pt.ag.Jor). All isolates grew on minimal media (MM) in the presence of acephate at 100 and 200 ppm, with maximum growth at 200 ppm. LC-MS analyses of spent medium showed that E. asburiae degraded acephate to methamidophos and O, O-dimethyl phosporamidate and B. cereus O,S-dimethyl to phosphorothioate but P. agglomerans to an unnamed compound. All three isolates used acephate as a source of carbon and energy for growth; however, P. agglomerans used it also as source of sulphur. Strong evidence revealed that the bacterial communities present in the gut of diamondback moth might aid in acephate degradation and play a role in the development of insecticide resistance. PMID:27498509

  4. Lactobacillus bulgaricus Prevents Intestinal Epithelial Cell Injury Caused by Enterobacter sakazakii-Induced Nitric Oxide both In Vitro and in the Newborn Rat Model of Necrotizing Enterocolitis▿

    PubMed Central

    Hunter, Catherine J.; Williams, Monica; Petrosyan, Mikael; Guner, Yigit; Mittal, Rahul; Mock, Dennis; Upperman, Jeffrey S.; Ford, Henri R.; Prasadarao, Nemani V.

    2009-01-01

    Enterobacter sakazakii is an emerging pathogen that has been associated with outbreaks of necrotizing enterocolitis (NEC) as well as infant sepsis and meningitis. Our previous studies demonstrated that E. sakazakii induces NEC in a newborn rat model by inducing enterocyte apoptosis. However, the mechanisms responsible for enterocyte apoptosis are not known. Here we demonstrate that E. sakazakii induces significant production of nitric oxide (NO) in rat intestinal epithelial cells (IEC-6) upon infection. The elevated production of NO, which is due to increased expression of inducible NO synthase, is responsible for apoptosis of IEC-6 cells. Notably, pretreatment of IEC-6 cells with Lactobacillus bulgaricus (ATCC 12278) attenuated the upregulation of NO production and thereby protected the cells from E. sakazakii-induced apoptosis. Furthermore, pretreatment with L. bulgaricus promoted the integrity of enterocytes both in vitro and in the infant rat model of NEC, even after challenge with E. sakazakii. Infection of IEC-6 cells with E. sakazakii upregulated several genes related to apoptosis, cytokine production, and various signaling pathways, as demonstrated by rat gene array analysis, and this upregulation was subdued by pretreatment with L. bulgaricus. In agreement with these data, L. bulgaricus pretreatment protected newborn rats infected with E. sakazakii from developing NEC, resulting in improved survival. PMID:19075027

  5. Increased growth and root Cu accumulation of Sorghum sudanense by endophytic Enterobacter sp. K3-2: Implications for Sorghum sudanense biomass production and phytostabilization.

    PubMed

    Li, Ya; Wang, Qi; Wang, Lu; He, Lin-Yan; Sheng, Xia-Fang

    2016-02-01

    Endophytic bacterial strain K3-2 was isolated from the roots of Sorghum sudanense (an bioenergy plant) grown in a Cu mine wasteland soils and characterized. Strain K3-2 was identified as Enterobacter sp. based on 16S rRNA gene sequence analysis. Strain K3-2 exhibited Cu resistance and produced 1-aminocyclopropane-1-carboxylate (ACC) deaminase, indole-3-acetic acid (IAA), siderophores, and arginine decarboxylase. Pot experiments showed that strain K3-2 significantly increased the dry weight and root Cu accumulation of Sorghum sudanense grown in the Cu mine wasteland soils. Furthermore, increase in total Cu uptake (ranging from 49% to 95%) of the bacterial inoculated-Sorghum sudanense was observed compared to the control. Notably, most of Cu (83-86%) was accumulated in the roots of Sorghum sudanense. Furthermore, inoculation with strain K3-2 was found to significantly increase Cu bioconcentration factors and the proportions of IAA- and siderophore-producing bacteria in the root interiors and rhizosphere soils of Sorghum sudanense compared with the control. Significant decrease in the available Cu content was also observed in the rhizosphere soils of the bacterial-inoculated Sorghum sudanense. The results suggest that the endophytic bacterial strain K3-2 may be exploited for promoting Sorghum sudanense biomass production and Cu phytostabilization in the Cu mining wasteland soils. PMID:26517728

  6. Plasmid load adversely affects growth and gluconic acid secretion ability of mineral phosphate-solubilizing rhizospheric bacterium Enterobacter asburiae PSI3 under P limited conditions.

    PubMed

    Sharma, Vikas; Archana, G; Naresh Kumar, G

    2011-01-20

    Effect of the metabolic load caused by the presence of plasmids on mineral phosphate-solubilizing (MPS) Enterobacter asburiae PSI3, was monitored with four plasmid cloning vectors and one native plasmid, varying in size, nature of the replicon, copy number and antibiotic resistance genes. Except for one plasmid, the presence of all other plasmids in E. asburiae PSI3 resulted in the loss of the MPS phenotype as reflected by the failure to bring about a drop in pH and release soluble P when grown in media containing rock phosphate (RP) as the sole P source. When 100 μM soluble P was supplemented along with RP, the adverse effects of plasmids on MPS phenotype and on growth parameters was reduced for some plasmid bearing derivatives, as monitored in terms of specific growth rates, glucose consumed, gluconic acids yields and P released. When 10 mM of soluble P as the only P source, was added to the medium all transformants showed growth and pH drop comparable with native strain. It may be concluded that different plasmids impose, to varying extents, a metabolic load in the phosphate-solubilizing bacterium E. asburiae PSI3 and results in diminishing its growth and P-solubilizing ability in P deficient conditions. PMID:20171856

  7. Production, characterization, and flocculation mechanism of cation independent, pH tolerant, and thermally stable bioflocculant from Enterobacter sp. ETH-2.

    PubMed

    Tang, Wei; Song, Liyan; Li, Dou; Qiao, Jing; Zhao, Tiantao; Zhao, Heping

    2014-01-01

    Synthetic high polymer flocculants, frequently utilized for flocculating efficiency and low cost, recently have been discovered as producing increased risk to human health and the environment. Development of a more efficient and environmentally sound alternative flocculant agent is investigated in this paper. Bioflocculants are produced by microorganisms and may exhibit a high rate of flocculation activity. The bioflocculant ETH-2, with high flocculating activity (2849 mg Kaolin particle/mg ETH-2), produced by strain Enterobacter sp. isolated from activated sludge, was systematically investigated with regard to its production, characterization, and flocculation mechanism. Analyses of microscopic observation, zeta potential and ETH-2 structure demonstrates the bridging mechanism, as opposed to charge neutralization, was responsible for flocculation of the ETH-2. ETH-2 retains high molecular weight (603 to 1820 kDa) and multi-functional groups (hydroxyl, amide and carboxyl) that contributed to flocculation. Polysaccharides mainly composed of mannose, glucose, and galactose, with a molar ratio of 1:2.9:9.8 were identified as the active constituents in bioflocculant. The structure of the long backbone with active sites of polysaccharides was determined as a primary basis for the high flocculation activity. Bioflocculant ETH-2 is cation independent, pH tolerant, and thermally stable, suggesting a potential fit for industrial application. PMID:25485629

  8. [Post-marketing surveillance of antibacterial activities of cefozopran against various clinical isolates--II. Gram-negative bacteria].

    PubMed

    Igari, Jun; Oguri, Toyoko; Hiramatsu, Nobuyoshi; Akiyama, Kazumitsu; Koyama, Tsuneo

    2003-10-01

    As a post-marketing surveillance, the in vitro antibacterial activities of cefozopran (CZOP), an agent of cephems, against various clinical isolates were yearly evaluated and compared with those of other cephems, oxacephems, carbapenems, monobactams, and penicillins. Changes in CZOP susceptibility among bacteria were also evaluated with the bacterial resistance ratio calculated from the breakpoint MIC. Twenty-five species (4,154 strains) of Gram-negative bacteria were isolated from the clinical materials annually collected from 1996 to 2001, and consisted of Moraxella (Branhamella) catarrhalis, Haemophilus influenzae, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Enterobacter aerogenes, Serratia marcescens, Serratia liquefaciens, Citrobacter freundii, Citrobacter koseri, Proteus mirabilis, Proteus vulgaris, Morganella morganii, Providencia spp., Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas putida, Acinetobacter baumannii, Acinetobacter Iwoffii, Burkholderia cepacia, Stenotrophomonas maltophilia, Bacteroides fragilis group, and Prevotella/Porphyromonas. CZOP preserved its antibacterial activity against M. (B.) catarrhalis (MIC90: 4 micrograms/mL) and showed comparable activity to carbapenems against H. influenzae (MIC90: 1 microgram/mL). The antibacterial activity of CZOP against E. coli was preferable (MIC90: 0.125 microgram/mL) and comparable to those of cefpirome (CPR), cefepime (CFPM), and imipenem (IPM). The MIC90 of CZOP against K. pneumoniae and K. oxytoca was 1 and 0.25 microgram/mL, respectively. The MIC90 of CZOP against E. cloacae increased during 6 years (32 to 128 micrograms/mL). The antibacterial activity of CZOP against E. aerogenes was preferable (MIC90: 1 microgram/mL). The antibacterial activities of CZOP against S. marcescens and S. liquefaciens were relatively potent (MIC90: 0.5 and 0.25 microgram/mL) and comparable to those of CPR, CFPM, and carumonam. CZOP preserved comparable antibacterial

  9. Comparison of three chromogenic media and evaluation of two molecular-based identification systems for the detection of Enterobacter sakazakii from environmental samples from infant formulae factories.

    PubMed

    Derzelle, Sylviane; Dilasser, Françoise; Maladen, Véronique; Soudrie, Nicole; Leclercq, Alexandre; Lombard, Bertrand; Lafarge, Veŕonique

    2007-07-01

    Enterobacter sakazakii is an occasional contaminant of powdered infant formula that can cause rare but severe foodborne infections in infants. To determine optimal methods for the detection and identification of E. sakazakii, 38 naturally contaminated samples from infant formulae factories were analyzed by two PCR-based methods and by a method (TS 22964/RM 210) developed by the International Organization for Standardization and the International Dairy Federation (ISO-IDF) using three different commercial chromogenic agars. The ISO-IDF method includes two enrichment steps, plating of the second enrichment broth on E. sakazakii isolation agar (a chromogenic selective agar), picking of five typical colonies for transfer onto tryptone soy agar, and subsequent confirmation of yellow-pigmented colonies by biochemical characterization. Twenty-two of the 38 samples were positive by the culture method. E. sakazakii isolation agar (ESIA; AES Laboratoires), COMPASS agar (Biokar Diagnostics), and Druggan-Forsythe-Iversen agar (Oxoid) compared favorably with violet red bile glucose agar (VRBG, a selective medium for Enterobacteriaceae), with positive predictive values of 86.96, 88, and 74.07%, respectively, in contrast to 47.83% for VRBG. One additional positive sample was detected using the nonpatented real-time PCR method evaluated, and those results were in 97.3% concordance with the ISO-IDF results. Some discrepancies between the results of the DuPont Qualicon BAX system and those of the ISO-IDF method could be explained by heterogeneity of contamination and sampling. Thus, both PCR-based systems were suitable for detecting and specifically identifying E. sakazakii within 1 to 2 days, and COMPASS agar and ESIA could be used interchangeably as a first-step medium to isolate presumptive E. sakazakii colonies. PMID:17685342

  10. Evaluation of a biocontrol preparation consisting of Enterobacter asburiae JX1 and a lytic bacteriophage cocktail to suppress the growth of Salmonella Javiana associated with tomatoes.

    PubMed

    Ye, Jianxiong; Kostrzynska, Magdalaena; Dunfield, Kari; Warriner, Keith

    2009-11-01

    A biocontrol preparation based on a combination of Enterobacter asburiae JX1 and a cocktail of five lytic bacteriophages was evaluated for control of Salmonella Javiana within the rhizosphere of plants and in pre- and postharvest tomatoes. The biocontrol preparation introduced into the rhizosphere of growing tomato plants reduced the persistence of Salmonella, although no synergistic action was observed between E. asburiae JX1 or the bacteriophage cocktail when used in combination. When the biocontrol preparation was coinoculated with Salmonella onto the blossom of tomato plants, the prevalence of the enteric pathogen both on the surface and in internal tissues of the subsequent tomatoes was significantly reduced compared with controls. Tomatoes derived from plants inoculated with Salmonella alone had a prevalence of 92% surface contamination (22 of 24 tomato batches were positive for Salmonella) and 43% internal contamination (31 of 72 batches positive). This Salmonella prevalence was reduced to 0% (0 of 38 positive) and 2% (1 of 57 positive), respectively, when the biocontrol preparation was applied. Although bacteriophages reduced the prevalence of internalized Salmonella, the main growth suppressing effect was via the antagonistic activity of E. asburiae JX1. No bacteriophages were recovered from tomatoes despite being introduced at 6 log PFU onto the blossom of plants. The biocontrol preparation was not effective for controlling the growth of Salmonella introduced onto postharvest tomatoes that were stored for 7 days at 15 degrees C. The application of E. asburiae JX1 is a promising approach for controlling Salmonella encountered in tomato production, and there was no evidence to suggest that the antagonistic activity could be enhanced by the coinoculation of bacteriophages. PMID:19903390

  11. Regulation of nif gene expression in Enterobacter agglomerans: nucleotide sequence of the nifLA operon and influence of temperature and ammonium on its transcription.

    PubMed

    Siddavattam, D; Steibl, H D; Kreutzer, R; Klingmüller, W

    1995-12-20

    The nucleotide sequence of a plasmid-borne 3.9 kb XhoI-SmaI fragment comprising the 3'-region of the nifM gene, the nifL and nifA genes and the 5'-region of nifB gene of Enterobacter agglomerans was determined. The genes were identified by their homology to the corresponding nif genes of Klebsiella pneumoniae. A typical sigma 54-dependent promoter and a consensus NtrC-binding motif were identified upstream of nifL. The predicted amino acid sequence of NifL showed close similarities to NifL of K. pneumoniae and Azotobacter vinelandii. However, no histidine residue was found to correspond to histidine-304 of A. vinelandii NifL, which had been proposed to be required for the repressor activity of NifL. The NifA sequence with a putative DNA binding motif (Q(x3) A(x3) G(x5)I) and an ATP binding site in the C-terminal and central domains, respectively, resembles that of other known NifA proteins. The function of the nifL and nifA genes was demonstrated in vivo using a binary plasmid system by their ability to activate a nifH promoter-lacZ fusion at different temperatures and concentrations of NH4+. Maximal promoter activity occurred at 25 degrees C, and it appears that the sensitivity of NifA to elevated temperatures is independent of NifL. The expression of nifL inhibited promoter activity in the presence of NifA when the initial NH4+ concentration in the medium exceeded 4 mM. PMID:8544828

  12. Association between the Presence of Aminoglycoside-Modifying Enzymes and In Vitro Activity of Gentamicin, Tobramycin, Amikacin, and Plazomicin against Klebsiella pneumoniae Carbapenemase- and Extended-Spectrum-β-Lactamase-Producing Enterobacter Species.

    PubMed

    Haidar, Ghady; Alkroud, Ammar; Cheng, Shaoji; Churilla, Travis M; Churilla, Bryce M; Shields, Ryan K; Doi, Yohei; Clancy, Cornelius J; Nguyen, M Hong

    2016-09-01

    We compared the in vitro activities of gentamicin (GEN), tobramycin (TOB), amikacin (AMK), and plazomicin (PLZ) against 13 Enterobacter isolates possessing both Klebsiella pneumoniae carbapenemase and extended-spectrum β-lactamase (KPC+/ESBL+) with activity against 8 KPC+/ESBL-, 6 KPC-/ESBL+, and 38 KPC-/ESBL- isolates. The rates of resistance to GEN and TOB were higher for KPC+/ESBL+ (100% for both) than for KPC+/ESBL- (25% and 38%, respectively), KPC-/ESBL+ (50% and 17%, respectively), and KPC-/ESBL- (0% and 3%, respectively) isolates. KPC+/ESBL+ isolates were more likely than others to possess an aminoglycoside-modifying enzyme (AME) (100% versus 38%, 67%, and 5%; P = 0.007, 0.06, and <0.0001, respectively) or multiple AMEs (100% versus 13%, 33%, and 0%, respectively; P < 0.01 for all). KPC+/ESBL+ isolates also had a greater number of AMEs (mean of 4.6 versus 1.5, 0.9, and 0.05, respectively; P < 0.01 for all). GEN and TOB MICs were higher against isolates with >1 AME than with ≤1 AME. The presence of at least 2/3 of KPC, SHV, and TEM predicted the presence of AMEs. PLZ MICs against all isolates were ≤4 μg/ml, regardless of KPC/ESBL pattern or the presence of AMEs. In conclusion, GEN and TOB are limited as treatment options against KPC+ and ESBL+ Enterobacter PLZ may represent a valuable addition to the antimicrobial armamentarium. A full understanding of AMEs and other aminoglycoside resistance mechanisms will allow clinicians to incorporate PLZ rationally into treatment regimens. The development of molecular assays that accurately and rapidly predict antimicrobial responses among KPC- and ESBL-producing Enterobacter spp. should be a top research priority. PMID:27297487

  13. Geraniol Restores Antibiotic Activities against Multidrug-Resistant Isolates from Gram-Negative Species▿ †

    PubMed Central

    Lorenzi, Vannina; Muselli, Alain; Bernardini, Antoine François; Berti, Liliane; Pagès, Jean-Marie; Amaral, Leonard; Bolla, Jean-Michel

    2009-01-01

    The essential oil of Helichrysum italicum significantly reduces the multidrug resistance of Enterobacter aerogenes, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. Combinations of the two most active fractions of the essential oil with each other or with phenylalanine arginine β-naphthylamide yield synergistic activity. Geraniol, a component of one fraction, significantly increased the efficacy of β-lactams, quinolones, and chloramphenicol. PMID:19258278

  14. A Simple Alternative to the IMViC Test in Microbiology.

    ERIC Educational Resources Information Center

    Benathen, Isaiah A.

    1992-01-01

    Presents a singular alternative to the Indole Methyl-red Voges-Proskauer Citrate (IMViC) test that uses bile-esculin agar to distinguish between the Escherichia coli and Enterobacter aerogenes bacteria. Includes materials and methods, results, and conclusions for the test. (MDH)

  15. Four Carbapenem-Resistant Gram-Negative Species Carrying Distinct Carbapenemases in a Single Patient

    PubMed Central

    Ding, Baixing; Hu, Fupin; Yang, Yang; Guo, Qinglan; Huang, Jinwei

    2014-01-01

    Carbapenem-resistant Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, and Acinetobacter baumannii were isolated from a single patient, each producing different carbapenemases (NDM-1, KPC-2, IMP, and OXA-23, respectively). The NDM-1-producing E. coli strain was preceded by a clonally related carbapenem-susceptible strain a month earlier, suggesting in vivo acquisition of blaNDM-1. PMID:25552359

  16. Significance of bacterial flora in abdominal irradiation-induced inhibition of lung metastases

    SciTech Connect

    Matsumoto, T.; Ando, K.; Koike, S.

    1988-06-01

    We have previously reported that abdominal irradiation prior to i.v. injection of syngeneic tumor cells reduced metastases in lung. Our report described an investigation of the significance of intestinal organisms in the radiation effect. We found that eliminating intestinal organisms with antibiotics totally abolished the radiation effect. Monoassociation of germ-free mice revealed that the radiation effect was observable only for Enterobacter cloacae, never for Streptococcus faecium, Bifidobacterium adlesentis, or Escherichia coli. After abdominal irradiation of regular mice, E. cloacae multiplied in cecal contents, adhered to mucous membranes, invaded the cecal wall, and translocated to mesenteric lymph nodes. Intravenous administration of E. cloacae in place of abdominal irradiation inhibited metastases. E. cloacae-monoassociated mice developed fewer metastases than germ-free mice, and the reduction was further enhanced by abdominal irradiation. We concluded that abdominal irradiation caused the invasion of E. cloacae from the mucous membrane of the intestine and inhibited formation of lung metastases.

  17. Multifarious beneficial traits and plant growth promoting potential of Serratia marcescens KiSII and Enterobacter sp. RNF 267 isolated from the rhizosphere of coconut palms (Cocos nucifera L.).

    PubMed

    George, Priya; Gupta, Alka; Gopal, Murali; Thomas, Litty; Thomas, George V

    2013-01-01

    Two plant growth promoting bacteria designated as KiSII and RNF 267 isolated from the rhizosphere of coconut palms were identified as Serratia marcescens and Enterobacter sp. based on their phenotypic features, BIOLOG studies and 16S rRNA gene sequence analysis. Both bacteria exhibited phosphate solubilization, ammonification, and production of indole acetic acid, β-1, 3 glucanase activities and 1-aminocyclopropane-1-carboxylate-deaminase activity. They could also tolerate a range of pH conditions, low temperature and salinity (NaCl). In addition, S. marcescens KiSII exhibited N- fixation potential, chitinase activity, siderophore production and antibiotics production. Seed bacterization with these bacteria increased the growth parameters of test plants such as paddy and cowpea over uninoculated control in green house assay. In coconut seedlings, significant increase in growth and nutrient uptake accompanied with higher populations of plant beneficial microorganisms in their rhizospheres were recorded on inoculation with both the PGPRs. The present study clearly revealed that PGPRs can aid in production of healthy and vigorous seedlings of coconut palm which are hardy perennial crops. They offer a scope to be developed into novel PGPR based bioinoculants for production of elite seedlings that can benefit the coconut farming community and the coconut based ecology. PMID:22948479

  18. Metabolism of the /sup 18/O-methoxy substituent of 3-methoxybenzoic acid and other unlabeled methoxybenzoic acids by anaerobic bacteria. [Eubacterium limosum; Acetobacterium woodil; Syntrophococcus; Clostridium; Desulfotomaculum; Enterobacter

    SciTech Connect

    DeWeerd, J.A.; Saxena, A.; Nagle, D.P. Jr.; Sulflita, J.M.

    1988-05-01

    The mechanism of the bioconversion of methoxylated benzoic acids to the hydroxylated derivatives was investigated with a model substrate and cultures of one anaerobic consortium, eight strict anaerobic bacteria, and one facultative anaerobic microorganism. We found that a haloaromatic dehalogenating consortium, a dehalogenating isolate from that consortium, Eubacterium, limosum, and a strain of Acetobacterium woodii metabolized 3-(methoxy-/sup 18/O)methoxybenzoic acid (3-anisic acid) to 3-(hydroxy-/sup 18/O)hydroxybenzoic acid stoichiometrically at rates of 1.5, 3.2, 52.4, and 36.7 nmol/min per mg of protein, respectively. A different strain of Acetobacterium and strains of Syntrophococcus, Clostridium Desulfotomaculum, Enterobacter, and an anaerobic bacterium, strain TH-001, were unable to transform this compound. The O-demethylating ability of E. limosum was induced only with appropriate methoxylated benzoates but not with D-glucose, lactate, isoleucine, or methanol. Cross-acclimation and growth experiments with E. limosum showed a rate of metabolism that was an order of magnitude slower and showed no growth with either 4-methoxysalicylic acid (2-hydroxy-4-methoxybenzoic acid) or 4-anisic acid (4-methoxybenzoic acid) when adapted to 3-anisic acid. However, A. woodii NZva-16 showed slower rates and no growth with 3- or 4-methoxysalicylic acid when adapted to 3-anisic acid in similar experiments.

  19. Multiplex PCR and a chromogenic DNA macroarray for the detection of Listeria monocytogens, Staphylococcus aureus, Streptococcus agalactiae, Enterobacter sakazakii, Escherichia coli O157:H7, Vibrio parahaemolyticus, Salmonella spp. and Pseudomonas fluorescens in milk and meat samples.

    PubMed

    Chiang, Yu-Cheng; Tsen, Hau-Yang; Chen, Hsin-Yen; Chang, Yu-Hsin; Lin, Chien-Ku; Chen, Chih-Yuan; Pai, Wan-Yu

    2012-01-01

    Food products, such as milk and meat products including cheese, milk powder, fermented milk, sausage, etc. are susceptible to the contamination by pathogenic and deteriorative bacteria. These bacteria include Listeria monocytogens, Staphylococcus aureus, Enterobacter sakazakii, Escherichia coli O157:H7, Salmonella spp., Vibrio parahaemolyticus, Streptococcus agalactiae and Pseudomonas fluorescens, etc. Traditional methods for the detection of these microorganisms are laborious and time consuming. Therefore, rapid and accurate diagnostic methods are needed. In this study, we designed the DNA probes and PCR primers for the detection of aforementioned microorganisms. By using two sets of multiplex PCR, followed by a chromogenic macroarray system, these organisms in milk or other food products could be simultaneously detected. When the system was used for the inspection of milk or meat homogenate containing 10(0) target cells per milliliter or gram of the sample, all these bacterial species could be identified after an 8h pre-enrichment step. The system consisting of a multiplex PCR step followed by macroarray allowed us to detect multiple target bacterial species simultaneously without the use of agarose gel electrophoresis. Compared to the commonly used multiplex PCR method, this approach has the additional advantage of detecting more bacterial strains because some bacterial strains generate PCR products with the same molecular sizes which can be differentiated by macroarray but not by electrophoresis. PMID:22101309

  20. Epidemiological Characteristics of blaNDM-1 in Enterobacteriaceae and the Acinetobacter calcoaceticus-Acinetobacter baumannii Complex in China from 2011 to 2012

    PubMed Central

    Ou, Weimei; Cui, Lanqing; Li, Yun; Zheng, Bo; Lv, Yuan

    2014-01-01

    Objectives The study aimed to investigate the prevalence and epidemiological characteristics of blaNDM-1 (encoding New Delhi metallo-β-lactamase 1) in Enterobacteriaceae and the Acinetobacter calcoaceticus-Acinetobacter baumannii complex (ABC) in China from July 2011 to June 2012. Methods PCR was used to screen for the presence of blaNDM-1 in all organisms studied. For blaNDM-1-positive strains, 16S rRNA analysis and Analytical Profile Index (API) strips were used to identify the bacterial genus and species. The ABCs were reconfirmed by PCR detection of blaOXA-51-like. Antibiotic susceptibilities of the bacteria were assessed by determining minimum inhibitory concentration (MIC) of them using two-fold agar dilution test, as recommended by the Clinical and Laboratory Standards Institute (CLSI). Molecular typing was performed using pulsed-field gel electrophoresis (PFGE). S1 nuclease-pulsed-field gel electrophoresis (S1-PFGE) and Southern blot hybridization were conducted to ascertain the gene location of blaNDM-1. Conjugation experiments were conducted to determine the transmission of blaNDM-1-positive strains. Results Among 2,170 Enterobacteriaceae and 600 ABCs, seven Enterobacteriaceae strains and two A. calcoaceticus isolates from five different cities carried the blaNDM-1 gene. The seven Enterobacteriaceae strains comprised four Klebsiella pneumoniae, one Enterobacter cloacae, one Enterobacter aerogen and one Citrobacter freundii. All seven were non-susceptible to imipenem, meropenem or ertapenem. Two A. calcoaceticus species were resistant to imipenem and meropenem. Three K. pneumoniae showed the same PFGE profiles. The blaNDM-1 genes of eight strains were localized on plasmids, while one was chromosomal. Conclusions Compared with previous reports, the numbers and species containing the blaNDM-1 in Enterobacteriaceae have significantly increased in China. Most of them are able to disseminate the gene, which is cause for concern. Consecutive surveillance should

  1. Molecular Characteristics of Extended-Spectrum Cephalosporin-Resistant Enterobacteriaceae from Humans in the Community

    PubMed Central

    van Hoek, Angela H. A. M.; Schouls, Leo; van Santen, Marga G.; Florijn, Alice; de Greeff, Sabine C.; van Duijkeren, Engeline

    2015-01-01

    Objective To investigate the molecular characteristics of extended-spectrum cephalosporin (ESC)-resistant Enterobacteriaceae collected during a cross-sectional study examining the prevalence and risk factors for faecal carriage of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in humans living in areas with high or low broiler density. Methods ESC-resistant Enterobacteriaceae were identified by combination disc-diffusion test. ESBL/AmpC/carbapenemase genes were analysed using PCR and sequencing. For E. coli, phylogenetic groups and MLST were determined. Plasmids were characterized by transformation and PCR-based replicon typing. Subtyping of plasmids was done by plasmid multilocus sequence typing. Results 175 ESC-resistant Enterobacteriaceae were cultured from 165/1,033 individuals. The isolates were Escherichia coli(n=65), Citrobacter freundii (n=52), Enterobacter cloacae (n=38), Morganella morganii (n=5), Enterobacter aerogenes (n=4), Klebsiella pneumoniae (n=3), Hafnia alvei (n=2), Shigella spp. (n=2), Citrobacter amalonaticus (n=1), Escherichia hermannii (n=1), Kluyvera cryocrescens (n=1), and Pantoea agglomerans (n=1). The following ESBL genes were recovered in 55 isolates originating from 49 of 1,033 (4.7 %) persons: blaCTX-M-1 (n=17), blaCTX-M-15 (n=16), blaCTX-M-14 (n=9), blaCTX-M-2 (n=3), blaCTX-M-3 (n=2), blaCTX-M-24 (n=2), blaCTX-M-27 (n=1), blaCTX-M-32 (n=1), blaSHV-12 (n=2), blaSHV-65 (n=1) and blaTEM-52 (n=1). Plasmidic AmpC (pAmpC) genes were discovered in 6 out of 1,033 (0.6 %) persons. One person carried two different E. coli isolates, one with blaCTX-M-1 and the other with blaCMY-2 and therefore the prevalence of persons carrying Enterobacteriaceae harboring ESBL and/or pAmpC genes was 5.2 %. In eight E. coli isolates the AmpC phenotype was caused by mutations in the AmpC promoter region. No carbapenemase genes were identified. A large variety of E. coli genotypes was found, ST131 and ST10 being most common. Conclusions ESBL

  2. Antibiotic resistance in outpatient urinary isolates: final results from the North American Urinary Tract Infection Collaborative Alliance (NAUTICA).

    PubMed

    Zhanel, George G; Hisanaga, Tamiko L; Laing, Nancy M; DeCorby, Melanie R; Nichol, Kim A; Palatnik, Lorraine P; Johnson, Jack; Noreddin, Ayman; Harding, Godfrey K M; Nicolle, Lindsay E; Hoban, Daryl J

    2005-11-01

    The goal of the North American Urinary Tract Infection Collaborative Alliance (NAUTICA) study was to determine antibiotic susceptibility to commonly used agents for urinary tract infections against outpatient urinary isolates obtained in various geographic regions in the USA and Canada. Forty-one medical centres (30 from the USA and 11 from Canada) participated, with each centre submitting up to 50 consecutive outpatient midstream urine isolates. Isolates were identified to species level by the standard protocol of each laboratory. Susceptibility testing was determined using the National Committee for Clinical Laboratory Standards (NCCLS) microdilution method. Resistance breakpoints used were those published by the NCCLS, including: ampicillin (resistant > or = 32 microg/mL), sulphamethoxazole/trimethoprim (SMX/TMP) (resistant > or = 4 microg/mL), nitrofurantoin (resistant > or = 128 microg/mL), ciprofloxacin (resistant > or = 4 microg/mL) and levofloxacin (resistant > or = 8 microg/mL). Of the 1990 isolates collected, 75.1% (1494) were collected from the USA and 24.9% (496) were collected from Canada. The mean age of the patients was 48.3 years (range 1 month to 99 years), and 79.5% and 20.5% of isolates were obtained from women and men, respectively. The most common organisms were Escherichia coli (57.5%), Klebsiella pneumoniae (12.4%), Enterococcus spp. (6.6%), Proteus mirabilis (5.4%), Pseudomonas aeruginosa (2.9%), Citrobacter spp. (2.7%), Staphylococcus aureus (2.2%), Enterobacter cloacae (1.9%), coagulase-negative staphylococci (1.3%), Staphylococcus saprophyticus (1.2%), Klebsiella spp. (1.2%), Enterobacter aerogenes (1.1%) and Streptococcus agalactiae (1.0%). Among all 1990 isolates, 45.9% were resistant to ampicillin, 20.4% to SMX/TMP, 14.3% to nitrofurantoin, 9.7% to ciprofloxacin and 8.1% to levofloxacin. Fluoroquinolone resistance was highest in patients > or = 65 years of age. For the 1142 E. coli isolates, resistance rates were: ampicillin 37.7%, SMX

  3. Antagonistic effect of Lactobacillus strains against gas-producing coliforms isolated from colicky infants

    PubMed Central

    2011-01-01

    Background Infantile colic is a common disturb within the first 3 months of life, nevertheless the pathogenesis is incompletely understood and treatment remains an open issue. Intestinal gas production is thought to be one of the causes of abdominal discomfort in infants suffering from colic. However, data about the role of the amount of gas produced by infants' colonic microbiota and the correlation with the onset of colic symptoms are scanty. The benefit of supplementation with lactobacilli been recently reported but the mechanisms by which they exert their effects have not yet been fully defined. This study was performed to evaluate the interaction between Lactobacillus spp. strains and gas-forming coliforms isolated from stools of colicky infants. Results Strains of coliforms were isolated from stools of 45 colicky and 42 control breastfed infants in McConkey Agar and identified using PCR with species-specific primers, and the BBL™ Enterotube™ II system for Enterobacteriaceae. Gas-forming capability of coliforms was assessed in liquid cultures containing lactose as sole carbon source. The average count of total coliforms in colicky infants was significantly higher than controls: 5.98 (2.00-8.76) log10 vs 3.90 (2.50-7.10) CFU/g of faeces (p = 0.015). The following strains were identified: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Enterobacter cloacae and Enterococcus faecalis. Then, 27 Lactobacillus strains were tested for their antagonistic effect against coliforms both by halo-forming method and in liquid co-cultures. Lactobacillus delbrueckii subsp.delbrueckii DSM 20074 and L. plantarum MB 456 were able to inhibit all coliforms strains (halo-forming method), also in liquid co-cultures, thus demonstrating an antagonistic activity. Conclusions This study shows that two out of 27 strains of Lactobacillus examined possess an antimicrobial effect against six species of gas-forming coliforms isolated from colicky

  4. Single molecule sequencing to track plasmid diversity of hospital-associated carbapenemase-producing Enterobacteriaceae

    PubMed Central

    Conlan, Sean; Thomas, Pamela J.; Deming, Clayton; Park, Morgan; Lau, Anna F.; Dekker, John P.; Snitkin, Evan S.; Clark, Tyson A.; Luong, Khai; Song, Yi; Tsai, Yu-Chih; Boitano, Matthew; Gupta, Jyoti; Brooks, Shelise Y.; Schmidt, Brian; Young, Alice C.; Thomas, James W.; Bouffard, Gerard G.; Blakesley, Robert W.; Mullikin, James C.; Korlach, Jonas; Henderson, David K.; Frank, Karen M.; Palmore, Tara N.; Segre, Julia A.

    2014-01-01

    Public health officials have raised concerns that plasmid transfer between Enterobacteriaceae species may spread resistance to carbapenems, an antibiotic class of last resort, thereby rendering common healthcare-associated infections nearly impossible to treat. We performed comprehensive surveillance and genomic sequencing to identify carbapenem-resistant Enterobacteriaceae in the NIH Clinical Center patient population and hospital environment in order to to articulate the diversity of carbapenemase-encoding plasmids and survey the mobility of and assess the mobility of these plasmids between bacterial species. We isolated a repertoire of carbapenemase-encoding Enterobacteriaceae, including multiple strains of Klebsiella pneumoniae, Klebsiella oxytoca, Escherichia coli, Enterobacter cloacae, Citrobacter freundii, and Pantoea species. Long-read genome sequencing with full end-to-end assembly revealed that these organisms carry the carbapenem-resistance genes on a wide array of plasmids. Klebsiella pneumoniae and Enterobacter cloacae isolated simultaneously from a single patient harbored two different carbapenemase-encoding plasmids, overriding the epidemiological scenario of plasmid transfer between organisms within this patient. We did, however, find evidence supporting horizontal transfer of carbapenemase-encoding plasmids between Klebsiella pneumoniae, Enterobacter cloacae and Citrobacter freundii in the hospital environment. Our comprehensive sequence data, with full plasmid identification, challenges assumptions about horizontal gene transfer events within patients and identified wider possible connections between patients and the hospital environment. In addition, we identified a new carbapenemase-encoding plasmid of potentially high clinical impact carried by Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae and Pantoea species, from unrelated patients and the hospital environment. PMID:25232178

  5. Polymicrobial Ventriculitis Involving Pseudomonas fulva

    PubMed Central

    Rebolledo, Paulina A.; Vu, Catphuong Cathy L.; Carlson, Renee Donahue; Kraft, Colleen S.; Anderson, Evan J.

    2014-01-01

    Infections due to Pseudomonas fulva remain a rare but emerging concern. A case of ventriculitis due to Enterobacter cloacae and Pseudomonas fulva following placement of an external ventricular drain is described. Similar to other reports, the organism was initially misidentified as Pseudomonas putida. The infection was successfully treated with levofloxacin. PMID:24648556

  6. The cutworm Peridroma saucia (Lepidoptera: Noctuidae) supports growth and transport of pBR322-bearing bacteria.

    PubMed

    Armstrong, J L; Porteous, L A; Wood, N D

    1989-09-01

    Variegated cutworms were exposed to bean plants in microcosms sprayed with pBR322-carrying strains of Enterobacter cloacae, Klebsiella planticola, and Erwinia herbicola. The three bacterial species exhibited differential survival on leaves, in soil, and in guts and fecal pellets (frass) of the insects. High numbers of Enterobacter cloacae(pBR322) were detected in all samples, while the other species were unable to establish residence in the insect. To assess the impact of this colonization on site-to-site transport of microorganisms, larvae were fed plants that had been sprayed with the bacteria and then were transferred to uninoculated plants. Cutworms were efficient carriers of Enterobacter cloacae(pBR322), as indicated by its rapid appearance on uninoculated leaves and continued persistence in the insects for 3 days after transfer. Few Erwinia herbicola(pBR322) and K. planticola(pBR322) were obtained from larvae after transfer, although up to 10(3) CFU/g were detected in soil and on plants. Differences in bacterial survival and growth were confirmed by incubating frass overnight and observing the change in population numbers. The proportion of total samples showing at least a 25-fold increase during incubation was 68% for Enterobacter cloacae(pBR322), 39% for K. planticola(pBR322), and 0% for Erwinia herbicola(pBR322). Our results emphasize the role that cutworms and possibly other insects have in persistence and growth of microorganisms in the environment. PMID:2802606

  7. The cutworm Peridroma saucia (Lepidoptera: Noctuidae) supports growth and transport of pBR322-bearing bacteria.

    PubMed Central

    Armstrong, J L; Porteous, L A; Wood, N D

    1989-01-01

    Variegated cutworms were exposed to bean plants in microcosms sprayed with pBR322-carrying strains of Enterobacter cloacae, Klebsiella planticola, and Erwinia herbicola. The three bacterial species exhibited differential survival on leaves, in soil, and in guts and fecal pellets (frass) of the insects. High numbers of Enterobacter cloacae(pBR322) were detected in all samples, while the other species were unable to establish residence in the insect. To assess the impact of this colonization on site-to-site transport of microorganisms, larvae were fed plants that had been sprayed with the bacteria and then were transferred to uninoculated plants. Cutworms were efficient carriers of Enterobacter cloacae(pBR322), as indicated by its rapid appearance on uninoculated leaves and continued persistence in the insects for 3 days after transfer. Few Erwinia herbicola(pBR322) and K. planticola(pBR322) were obtained from larvae after transfer, although up to 10(3) CFU/g were detected in soil and on plants. Differences in bacterial survival and growth were confirmed by incubating frass overnight and observing the change in population numbers. The proportion of total samples showing at least a 25-fold increase during incubation was 68% for Enterobacter cloacae(pBR322), 39% for K. planticola(pBR322), and 0% for Erwinia herbicola(pBR322). Our results emphasize the role that cutworms and possibly other insects have in persistence and growth of microorganisms in the environment. PMID:2802606

  8. Multi-Strain Co-Cultures Surpass Blends for Broad Spectrum Biological Control of Maladies of Potatoes in Storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas fluorescens strains S11:P:12, P22:Y:05, and S22:T:04 and Enterobacter cloacae strain S11:T:07 have been documented to suppress four important storage potato maladies: dry rot, late blight, pink rot, and sprouting. This research investigates the efficacy and consistency of strain mixture...

  9. Professional Acquisition of M. bovis in Calabria Region (Southern Italy): A Challenging Case of Osteomyelitis in a Migrant Patient from Bulgaria

    PubMed Central

    Quirino, Angela; Torti, Carlo; Strazzulla, Alessio; Nisticò, Salvatore; Galati, Luisa; Barreca, Giorgio Settimo; Lamberti, Angelo Giuseppe; Berardelli, Giuseppina; Pacciarini, Maria; Gasparini, Giorgio; Pisani, Vincenzo; Gambardella, Antonio; Liberto, Maria Carla; Focà, Alfredo

    2015-01-01

    We report herein the first case of a coinfection with Brucella spp., M. bovis, and Enterobacter cloacae in a butcher who moved from Bulgaria to Italy. Molecular typing suggested professional acquisition of M. bovis in Italy. So, surveillance and preventive measures need to be implemented. PMID:26257970

  10. Papaya Varietal Resistance to Internal Yellowing: Reducing Food Safety Risk

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Internal yellowing (IY) is a bacterial disease of ripening papaya fruit that is caused by the enteric bacterium, Enterobacter cloacae. The disease is characterized by yellow discoloration of flesh, tissue softening and a foul or rotten odor that reduces the quality of fresh fruit and value-added pr...

  11. Nationwide Study of the Prevalence, Characteristics, and Molecular Epidemiology of Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae in France▿

    PubMed Central

    Galas, Muriel; Decousser, Jean-Winoc; Breton, Nelly; Godard, Thierry; Allouch, Pierre Yves; Pina, Patrick

    2008-01-01

    Among 10,872 isolates of Enterobacteriaceae from a nationwide study of 88 French hospitals in 2005, 169 (1.7%) expressed an extended-spectrum β-lactamase. The most prevalent species were Escherichia coli (48.5%), Enterobacter aerogenes (23.7%), and Klebsiella pneumoniae (14.8%). Molecular analysis underlined the polyclonal spread of CTX-M-expressing E. coli, primarily isolates of the CTX-M-1 subgroup. PMID:18025119

  12. Bacteria in midguts of field-collected Anopheles albimanus block Plasmodium vivax sporogonic development.

    PubMed

    Gonzalez-Ceron, Lilia; Santillan, Frida; Rodriguez, Mario H; Mendez, Domingo; Hernandez-Avila, Juan E

    2003-05-01

    Bacterial infections were investigated in midguts of insectary and field-collected Anopheles albimanus Weidemann from southern Mexico. Serratia marcescens, Enterobacter cloacae and Enterobacter amnigenus 2, Enterobacter sp., and Serratia sp. were isolated in field samples obtained in 1998, but only Enterobacter sp. was recovered in field samples of 1997 and no bacteria were isolated from insectary specimens. These bacteria were offered along with Plasmodium vivax infected blood to aseptic insectary An. albimanus, and the number of infected mosquitoes as well as the oocyst densities assessed after 7d. Plasmodium vivax infections in mosquitoes co-infected with En. amnigenus 2, En. cloacae, and S. marcensces were 53, 17, and 210 times, respectively, lower than in control mosquitoes, and the mean oocyst density in mosquitoes co-infected with En. cloacae was 2.5 times lower than in controls. Mortality was 13 times higher in S. marcensces-infected mosquitoes compared with controls. The overall midgut bacterial infection in mosquito field populations may influence P. vivax transmission, and could contribute to explain the annual variations in malaria incidence observed in the area. PMID:12943119

  13. Quality of powdered substitutes for breast milk with regard to members of the family Enterobacteriaceae.

    PubMed Central

    Muytjens, H L; Roelofs-Willemse, H; Jaspar, G H

    1988-01-01

    Members of the family Enterobacteriaceae were cultured from 52.5% of 141 milk substitute infant formulas which were obtained in 35 countries. The concentration did not exceed a level of 1 CFU/g in any product. The species which were isolated most frequently were Enterobacter agglomerans, cloacae, Enterobacter sakazakii, and Klebsiella pneumoniae. If infections due to these organisms occur, it can be useful to include a check of the hygienic precautions which are taken during the preparation and storage of the formula. Milk powders without members of the Enterobacteriaceae might offer extra protection to the newborn if some multiplication does occur in the formula. PMID:3284901

  14. Polymicrobial abdominal wall necrotizing fasciitis after cesarean section.

    PubMed

    DeMuro, Jp; Hanna, Af; Chalas, E; Cunha, Ba

    2012-01-01

    We report a case of a previously healthy woman after an uneventful caesarean section who developed polymicrobial necrotizing fasciitis. She was given a non-steroidal anti-inflamatory drug (NSAID) after her delivery. Her post-delivery course was complicated by septic shock, and required multiple debridements before abdominal reconstruction. This case describes the increased risk of necrotizing fasciitis with NSAID use. Unusual were the organisms causing the polymicrobial necrotizing fasciitis: Staphylococcus aureus, Enterobacter agglomerans, Acinetobacter baumannii, and two strains of Enterobacter cloacae. PMID:24960796

  15. Enteric group 17 in clinical isolates.

    PubMed

    Yang, D I; Chen, L C

    1989-11-01

    The Enteric Group 17, a new group of Enterobacteriaceae, has been classified (by the Centers for Disease Control, Atlanta, Georgia, U.S.A.) based on its positive methyl-red test as well as its negative response to Voges-Proskauer, motility, rhamnose and melibiose fermentation tests. The isolation rate of Enteric Group 17 among 500 clinical isolates of Enterobacteriaceae in Taiwan is 1.8% (9/500). This finding recommends that Taiwan's hospital laboratories should pay particular attention to the possible presence of this bacteria when an isolate has reactions similar to that of Enterobacter cloacae or other members of the Enterobacter species. PMID:2700157

  16. Characterization of Enterobacteria using MALDI-TOF mass spectrometry.

    PubMed

    Pribil, Patrick; Fenselau, Catherine

    2005-09-15

    A method is proposed for the rapid classification of Gram-negative Enterobacteria using on-slide solubilization and trypsin digestion of proteins, followed by MALDI-TOF MS analysis. Peptides were identified from tryptic digests using microsequencing by tandem mass spectrometry and database searches. Proteins from the outer membrane family (OMP) were consistently identified in the Enterobacteria Escherichia coli, Enterobacter cloacae, Erwinia herbicola, and Salmonella typhimurium. Database searches indicate that these OMP peptides observed are unique to the Enterobacteria order. PMID:16159146

  17. Emergence of New Delhi Metallo-Beta-Lactamase (NDM-1) and Klebsiella pneumoniae Carbapenemase (KPC-2) in South Africa

    PubMed Central

    Coetzee, Jennifer; Clay, Cornelis G.; Sithole, Sindi; Richards, Guy A.; Poirel, Laurent; Nordmann, Patrice

    2012-01-01

    This report documents emergence of New Delhi metallo-beta-lactamase (NDM-1) and Klebsiella pneumoniae carbapenemase (KPC-2) in K. pneumoniae and Enterobacter cloacae in South Africa. NDM-1 producers have not been described in South Africa, and this is the first instance that KPC producers have been identified in Africa. The two patients infected with these carbapenemase-producing bacteria demised. PMID:22116157

  18. Determination of antimicrobial activity and resistance to oxidation of moringa peregrina seed oil.

    PubMed

    Lalas, Stavros; Gortzi, Olga; Athanasiadis, Vasilios; Tsaknis, John; Chinou, Ioanna

    2012-01-01

    The antimicrobial activity of the oil extracted with n-hexane from the seeds of Moringa peregrina was tested against Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Candida albicans, C. tropicalis and C. glabrata. The oil proved effective against all of the tested microorganisms. Standard antibiotics (netilmycin, 5-flucytocine, intraconazole and 7-amino-4-methylcoumarin-3-acetic acid) were used for comparison. The resistance to oxidation of the extracted seed oil was also determined. PMID:22367027

  19. Cytotoxic and antibacterial labdane-type diterpenes from the aerial parts of Cistus incanus subsp. creticus.

    PubMed

    Chinou, I; Demetzos, C; Harvala, C; Roussakis, C; Verbist, J F

    1994-02-01

    Seven labdane-type diterpenoids were isolated from the leaves of Cistus incanus subsp. creticus; their structures were established by spectroscopic means. All compounds were tested in vitro for their cytotoxicity against three cell line systems: KB, P-388; and NSCLC-N6. Their antibacterial and antifungal activities were tested against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosae, Enterobacter cloacae, Escherichia coli, Klebsiella pneumonia, Torulopsis glabrata, Saccharomyces cerevisiae, and Candida albicans as well. PMID:8134413

  20. Volatiles produced by soil-borne endophytic bacteria increase plant pathogen resistance and affect tritrophic interactions

    PubMed Central

    Ton, Jurriaan; Brandenburg, Anna; Karlen, Danielle; Zopfi, Jakob; Turlings, Ted C. J.

    2014-01-01

    Volatile organic compounds (VOCs) released by soil microorganisms influence plant growth and pathogen resistance. Yet, very little is known about their influence on herbivores and higher trophic levels. We studied the origin and role of a major bacterial VOC, 2,3-butanediol (2,3-BD), on plant growth, pathogen and herbivore resistance, and the attraction of natural enemies in maize. One of the major contributors to 2,3-BD in the headspace of soil-grown maize seedlings was identified as Enterobacter aerogenes, an endophytic bacterium that colonizes the plants. The production of 2,3-BD by E. aerogenes rendered maize plants more resistant against the Northern corn leaf blight fungus Setosphaeria turcica. On the contrary, E. aerogenes-inoculated plants were less resistant against the caterpillar Spodoptera littoralis. The effect of 2,3-BD on the attraction of the parasitoid Cotesia marginiventris was more variable: 2,3-BD application to the headspace of the plants had no effect on the parasitoids, but application to the soil increased parasitoid attraction. Furthermore, inoculation of seeds with E. aerogenes decreased plant attractiveness, whereas inoculation of soil with a total extract of soil microbes increased parasitoid attraction, suggesting that the effect of 2,3-BD on the parasitoid is indirect and depends on the composition of the microbial community. PMID:24127750

  1. Volatiles produced by soil-borne endophytic bacteria increase plant pathogen resistance and affect tritrophic interactions.

    PubMed

    D'Alessandro, Marco; Erb, Matthias; Ton, Jurriaan; Brandenburg, Anna; Karlen, Danielle; Zopfi, Jakob; Turlings, Ted C J

    2014-04-01

    Volatile organic compounds (VOCs) released by soil microorganisms influence plant growth and pathogen resistance. Yet, very little is known about their influence on herbivores and higher trophic levels. We studied the origin and role of a major bacterial VOC, 2,3-butanediol (2,3-BD), on plant growth, pathogen and herbivore resistance, and the attraction of natural enemies in maize. One of the major contributors to 2,3-BD in the headspace of soil-grown maize seedlings was identified as Enterobacter aerogenes, an endophytic bacterium that colonizes the plants. The production of 2,3-BD by E. aerogenes rendered maize plants more resistant against the Northern corn leaf blight fungus Setosphaeria turcica. On the contrary, E. aerogenes-inoculated plants were less resistant against the caterpillar Spodoptera littoralis. The effect of 2,3-BD on the attraction of the parasitoid Cotesia marginiventris was more variable: 2,3-BD application to the headspace of the plants had no effect on the parasitoids, but application to the soil increased parasitoid attraction. Furthermore, inoculation of seeds with E. aerogenes decreased plant attractiveness, whereas inoculation of soil with a total extract of soil microbes increased parasitoid attraction, suggesting that the effect of 2,3-BD on the parasitoid is indirect and depends on the composition of the microbial community. PMID:24127750

  2. Enzymatic transesterification of Jatropha oil

    PubMed Central

    Kumari, Annapurna; Mahapatra, Paramita; Garlapati, Vijay Kumar; Banerjee, Rintu

    2009-01-01

    Background Transesterification of Jatropha oil was carried out in t-butanol solvent using immobilized lipase from Enterobacter aerogenes. The presence of t-butanol significantly reduced the negative effects caused by both methanol and glycerol. The effects of various reaction parameters on transesterification of Jatropha oil were studied. Results The maximum yield of biodiesel was 94% (of which 68% conversion was achieved with respect to methyl oleate) with an oil:methanol molar ratio of 1:4, 50 U of immobilized lipase/g of oil, and a t-butanol:oil volume ratio of 0.8:1 at 55°C after 48 h of reaction time. There was negligible loss in lipase activity even after repeated use for seven cycles. Conclusion To the best of our knowledge this is the first report on biodiesel synthesis using immobilized E. aerogenes lipase. PMID:19144158

  3. [Composting facilities. 2. Aerogenic microorganism content at different working areas of composting facilities].

    PubMed

    Jager, E; Rüden, H; Zeschmar-Lahl, B

    1994-12-01

    At two composting facilities (plants D and E), contamination of the air with total bacteria and mould fungi, and in addition with gram-negative bacteria (only at plant D) was analyzed at different indoor sites and outdoor in the vicinity. Statistical validity of the determination of contents of microorganisms in air samples was guaranteed by the collection and analysis of 30 parallel samples. At plant D, total bacteria concentrations in outdoor air ranged from 106 to 15,618 CFU/m3 air (median: 495 CFU/m3 air), gram-negative bacteria concentrations ranged up to 71 CFU/m3 air (median: below the detection limit of 35 CFU/m3 air), and mould fungi reached 7,138 CFU/m3 air (median: 141 CFU/m3 air). Highest concentrations of total bacteria above the upper detection limit (> 84,806 CFU/m3 air, sample volume: 28.3 l) and of mould fungi (38,940 CFU/m3 air) occurred at the place where three months old compost was mixed, highest concentrations of gram-negative bacteria (14,134 CFU/m3 air) were measured during mixing of fresh compost (younger than 8 days). Maximum and median values of the examined microorganisms ranged so high that special protective means for personnel working directly beneath the mixing process seem to be necessary under hygienic aspects. Raw and clean air at the composting filter at plant D showed highly significant differences concerning air concentration of gram-negative bacteria and mould fungi, indicating a good separation efficiency for these types of microorganisms. Maximum and median values of gram-negative bacteria and mould fungi concentrations (all < 1,000 CFU/m3 air) measured in clean air behind the composting filter lie in the range of normal outdoor air. Merely total bacteria show statistical significant differences to outdoor air with median values of clean air of 1,979 CFU/m3 air (edge of filter) resp. 3,110 CFU/m3 air (upside the filter) and with maximum values of above 30,000 CFU/m3 air in each case. In the outdoor air at plant E, total bacteria concentrations ranged from 362 to 7,633 CFU/m3 air (median: 1,312 CFU/m3 air), mould fungi ranged from 115 to 4,072 CFU/m3 air (median: 345 CFU/m3 air). Highest concentrations of total bacteria and mould fungi (all analyses above the upper detection limit of 21,201 CFU/m3 air; sample volume: 113,2 l) occurred during shredding of a mixture of kitchen and green wastes and of shrubs. During experimental shredding of separately collected panty diapers air concentrations of total bacteria ranged from about 19,000 CFU/m3 air to > 21,201 CFU/m3 air.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:7748441

  4. Bacteriological evaluation of pre-cut fruits sold in Kano metropolis, Kano State, Nigeria.

    PubMed

    Chukwu, O O C; Olabode, O A; Chukwuedo, A A; Umoh, E G; Esiekpe, M K

    2009-04-01

    One hundred and fifty (150) pre-cut fruit samples comprising of Pineapples (50), Paw-paw (50) and Watermelon (50) at the point of stand retail outlets were tested by standard bacteriological methods to determine bacterial contamination of the fruits. Out of these 150 examined 136 (90.67%) were contaminated with bacteria. The bacterial distribution were; Escherichia coli 69 (46.00%), Staphylococcus aureus 29 (19.33%), Salmonella species 13 (8.67%), Proteus species 18 (12.00%), Enterobacter aerogenes 3 (2.00%), Klebsiella pneumoniae 2 (1.33%) and Pseudomonas aeruginosa 2 (1.33%). Among the 50 Pineapple pre-cuts, Escherichia coli 26 (17.33%), Staphylococcus aureus 6 (4.00%), Salmonella species 7 (4.67%), Proteus species 9 (6.00%), Pseudomonas aeruginosa 2 (1.33%); the 50 Watermelon had Escherchia coli 22 (14.67%), Staphylococcus aureus 13 (8.67%), Salmonella species 3 (2.00%), Proteus species 5 (3.33%), Enterobacter aerogenes 2 (1.33%), Klebsiella species 2 (1.33%). Of the 50 Paw-paw pre-cuts were: Escherichia coli 21 (14.00%), Staphylococcus aureus 10 (6.67%), Salmonella species 3 (2.00%), Proteus species 4 (2.67%), Enterobacter aerogenes 1 (0.67%) were isolated. The findings in this study have shown that the food vendors failed to adopt adequate hygiene for food handling and thus, suggest that the quality of all the pre-cut fruits sold at the retail outlets were not bacteriologically satisfactory. The public health risks associated with these pre-cut fruits may suggest that these fruits could serve as the vehicles for foodborne illnesses. This study has shown the need to educate the vendors on how to protect utensils and fruits to avoid contamination and spoilage. PMID:20000065

  5. Antimicrobial activity of essential oil from Schinus molle Linn.

    PubMed

    Gundidza, M

    1993-11-01

    The essential oil from the fresh leaves of Schinus molle isolated by hydrodistillation was tested for antibacterial activity using the hole plate diffusion method and for antifungal activity using the mycelium or single cell growth inhibition method. Results obtained showed that the volatile oil exhibited significant activity against the following bacterial species: Klebsiella pneumoniae, Alcaligenes faecalis, Pseudomonas aeruginosa, Leuconostoc cremoris, Enterobacter aerogenes, Proteus vulgaris, Clostridium sporogenes, Acinetobacter calcoacetica, Escherichia coli, Beneckea natriegens, Citrobacter freundii, Serratia marcescens, Bacillus subtilis and Brochothrix thermosphacata. The fungal species Aspergillus ochraceus, Aspergillus parasiticus, Fusarium culmorum and Alternaria alternata exhibited significant sensitivity to the volatile oil. PMID:8055554

  6. A new antimicrobial and radical-scavenging glycoside from Paullinia pinnata var. cameroonensis.

    PubMed

    Lunga, Paul-Keilah; Qin, Xu-Jie; Yang, Xing-Wei; Kuiate, Jules-Roger; Du, Zhi-Zhi; Gatsing, Donatien

    2015-01-01

    A new glycoside, pinnatoside A (1), together with two known compounds (2 and 3), were isolated from the stems of Paullinia pinnata. Their structures were elucidated on the basis of extensive spectroscopic analysis and chemical methods. Compound 1 showed significant antibacterial activity with a minimum inhibitory concentration (MIC) value of 1.56 μg/mL against Escherichia coli, and 2 displayed significant antibacterial activity with a MIC value of 1.56 μg/mL against Enterobacter aerogenes and E. coli. Equally, compound 1 exhibited the best radical-scavenging activity (RSa50 = 25.07 ± 0.49 μg/mL). PMID:25563339

  7. Viable but nonculturable bacteria in drinking water.

    PubMed Central

    Byrd, J J; Xu, H S; Colwell, R R

    1991-01-01

    Klebsiella pneumoniae, Enterobacter aerogenes, Agrobacterium tumefaciens, Streptococcus faecalis, Micrococcus flavus, Bacillus subtilis, and Pseudomonas strains L2 and 719 were tested for the ability to grow and maintain viability in drinking water. Microcosms were employed in the study to monitor growth and survival by plate counts, acridine orange direct counts (AODC), and direct viable counts (DVC). Plate counts dropped below the detection limit within 7 days for all strains except those of Bacillus and Pseudomonas. In all cases, the AODC did not change. The DVC also did not change except that the DVC, on average, were ca. 10-fold lower than the AODC. PMID:2039237

  8. Microbiological quality and public health significance of ice-cream.

    PubMed

    Masud, T

    1989-04-01

    Fifty samples of ice-cream were subjected to microbiological examination. Of these 72% had total viable count over 10(6)/g while 66% had coliform count between 10(2)-10(3)/g. The micro-organisms isolated were Escherichia coli (46%), Enterobacter aerogenes (34%), Staphylococcus aureus (26%), proteus species (16%), Streptococcus faecalis (12%), Citrobacter species (10%) and Bacillus cereus (4%). The results showed that commercially prepared ice-cream sold in the market was not satisfactory for human consumption and preventive measures should be enforced for the supply of satisfactory products. PMID:2501524

  9. Cloning of aldB, which encodes alpha-acetolactate decarboxylase, an exoenzyme from Bacillus brevis.

    PubMed Central

    Diderichsen, B; Wedsted, U; Hedegaard, L; Jensen, B R; Sjøholm, C

    1990-01-01

    A gene for alpha-acetolactate decarboxylase (ALDC) was cloned from Bacillus brevis in Escherichia coli and in Bacillus subtilis. The 1.3-kilobase-pair nucleotide sequence of the gene, aldB, encoding ALDC and its flanking regions was determined. An open reading frame of 285 amino acids included a typical N-terminal signal peptide of 24 or 27 amino acids. A B. subtilis strain harboring the aldB gene on a recombinant plasmid processed and secreted ALDC. In contrast, a similar enzyme from Enterobacter aerogenes is intracellular. Images PMID:2198252

  10. Bio-reduction of Cr(VI) by exopolysaccharides (EPS) from indigenous bacterial species of Sukinda chromite mine, India.

    PubMed

    Harish, R; Samuel, Jastin; Mishra, R; Chandrasekaran, N; Mukherjee, A

    2012-07-01

    Chrome mining activity has contributed intensively towards pollution of hexavalent chromium around Sukinda Valley, Orissa, India. In an attempt to study the specific contribution of exopolysaccharides (EPS) extracted from indigenous isolates towards Cr(VI) reduction, three chromium (VI) tolerant strains were isolated from the effluent mining sludge. Based on the tolerance towards Cr(VI) and EPS production capacity, one of them was selected for further work. The taxonomic identity of the selected strain was confirmed to be Enterobacter cloacae (showing 98% similarity in BLAST search to E. cloacae) through 16S rRNA analysis. The EPS production was observed to increase with increasing Cr(VI) concentration in the growth medium, highest being 0.078 at 100 mg/l Cr(VI). The extracted EPS from Enterobacter cloacae SUKCr1D was able to reduce 31.7% of Cr(VI) at 10 mg/l concentration, which was relevant to the prevailing natural concentrations at Sukinda mine effluent sludge. The FT-IR spectral studies confirmed the surface chemical interactions of hexavalent chromium with EPS. PMID:22119897

  11. Cronobacter spp. (Enterobacter sakazakii): advice, policy and research in Canada.

    PubMed

    Pagotto, Franco J; Farber, Jeffrey M

    2009-12-31

    Although the number of reported cases of Cronobacter infection in Canada is low, Health Canada has been actively studying this organism since 1991. After reviewing the situation at the national level and due to health concerns with powdered formulae and its international trade, in 2003, Health Canada raised this issue at the international level by proposing to revise the Code of Practice for Powdered Formulae for Infants and Young Children at the Codex Alimentarius Committee of Food Hygiene. Canada volunteered to chair the Working Group that would be developing the Code, and the Code was completed in four years. The Code contributed to an improvement in the hygienic conditions in plants manufacturing Powdered Infant Formula (PIF), resulting in a lower level of product contamination with Cronobacter species. Canada has produced a document detailing Good Manufacturing Practices (GMPs) for Infant Formula in Canada. Health Canada uses the GMPs as a basis for assessing the manufacturing information received in pre-market notifications for new or changed infant formulas. Health Canada does not have microbiological criteria for Cronobacter spp. in PIF; however, we are currently working on developing these criteria. At present, there are no active or passive surveillance systems for Cronobacter spp. in Canada, although this has been discussed. Health Canada has recently adapted and condensed FAO/WHO guidelines to develop a draft guidance document for the hygienic preparation and handling of PIF in home and hospitals/care settings, which outline requirements for parents, caregivers, and staff in hospitals and day-care centres. Health Canada's Bureau of Microbial Hazards conducts research on the ecology, biology and pathogenesis of Cronobacter spp. Some of the research projects include specific aspects of molecular typing, virulence studies involving animal models, as well as in vitro tissue culture work to examine adhesion and invasion. Collaborative research is also being done with the Canadian National Research Council, using NMR and mass spectroscopy to reveal the structure of the O-polysaccharide of the various Cronobacter species. This review summarizes and discusses current activities that are being undertaken in Canada with respect to Cronobacter spp. PMID:19487040

  12. Intra- and inter-species spread of carbapenemase genes in a non-hospitalized patient.

    PubMed

    Sorlí, L; Miró, E; Segura, C; Navarro, F; Grau, S; Salvado, M; Horcajada, J P

    2011-12-01

    The purpose of this study was to report intra- and inter-species spread of carbapenemase genes between gram negative rods isolated from a non-hospitalized patient with bacteremia. The approach included chart review, antibiotic susceptibility testing and phenotypic screening for metallo-β-lactamase (MBL) detection, PCR and sequencing of bla, aac(6')-Ib and qnr genes, and plasmid analysis by PCR-based replicon typing. The clonal relationships between the isolates were analysed by comparing PFGE profiles. A non-hospitalized patient presented bacteraemia due to wild type Enterobacter cloacae (4.08), a VIM-1-producing E. cloacae (5.08), a VIM-1- and CTX-M-9-producing E. cloacae (7.08), a VIM-2-producing Pseudomonas aeruginosa, and catheter colonization by VIM-1-producing Klebsiella oxytoca. The patient had no previous hospitalization but had recently undergone an ambulatory colonoscopy. In E. cloacae 7.08 and K. oxytoca isolates, the bla(VIM-1) gene was located on a transferable plasmid of 48.5 kb, while in E. cloacae 5.08 the bla(VIM-1) gene was encoded on a 194 kb non-transferable plasmid. The bla(CTX-M-9) gene detected in E. cloacae was encoded on an HI2 plasmid of 290 kb. To date the prevalence of VIM-1 enzymes in the community is low. This molecular finding suggests an intra-species and/or inter-species horizontal spread of the MBL gene in the same non-hospitalized patient. PMID:21491175

  13. Analysis of bacterial diversity during the fermentation of inyu, a high-temperature fermented soy sauce, using nested PCR-denaturing gradient gel electrophoresis and the plate count method.

    PubMed

    Wei, Chia-Li; Chao, Shiou-Huei; Tsai, Wen-Bin; Lee, Pei-Shan; Tsau, Nai-Hung; Chen, Jhih-Shan; Lai, Wen-Lin; Tu, James Ching-Yueh; Tsai, Ying-Chieh

    2013-04-01

    The diversity of bacteria associated with the fermentation of inyu, also known as black soy sauce, was studied through the nested PCR-denaturing gradient gel electrophoresis (DGGE) of samples collected from the fermentation stages of the inyu production process. The DGGE profiles targeted the bacterial 16S rDNA and revealed the presence of Citrobacter farmeri, Enterobacter cloacae, Enterobacter hormaechei, Enterococcus faecium, Klebsiella pneumoniae, Pantoea agglomerans, Salmonella enterica, Serratia marcescens, Staphylococcus sciuri and Weissella confusa. The bacterial compositions of 4 fermented samples were further elucidated using the plate count method. The bacteria isolated from the koji-making stage exhibited the highest diversity; Brachybacterium rhamnosum, E. hormaechei, K. pneumoniae, Kurthia gibsonii, Pantoea dispersa, Staphylococcus gallinarum, Staphylococcus kloosii and S. sciuri were identified. Koji collected during the preincubation stage presented the largest cell counts, and E. hormaechei, K. pneumoniae, E. cloacae and Enterobacter pulveris were identified. In brine samples aged for 7 and 31 days, the majority of the bacteria isolated belonged to 4 Bacillus species, but 4 Staphylococcus species and Delftia tsuruhatensis were also detected. This study demonstrates the benefits of using a combined approach to obtain a more complete picture of microbial populations and provides useful information for the control or development of bacterial flora during inyu fermentation. PMID:23200659

  14. Antibacterial activity in the hemolymph of myriapods (Arthropoda).

    PubMed

    Xylander, W E; Nevermann, L

    1990-09-01

    The hemolymphs of two diplopod (Chicobolus sp. and Rhapidostreptus virgator) and two chilopod species (Lithobius forficatus and Scolopendra cingulata) were tested for the presence of antibacterial substances using Petri dish tests. The native hemolymph of all species had substances acting on living Micrococcus luteus, whereas only Rhapidostreptus, Scolopendra, and Lithobius were effective against lyophilized Micrococcus. The antibacterial activity against living Micrococcus increased after inoculation with bacteria (Enterobacter cloacae beta-12) in Chicobolus and Rhapidostreptus and also against lyophilized Micrococcus in the latter. Thus, these effects appear to be inducible. None of the myriapods tested had any bacteriostatic effect on Escherichia coli D-31 whereas the growth of gram-negative E. cloacae was inhibited. The antibacterial substances in the diplopod species were unstable when heated but were resistant to freezing. At least two antibacterial substances (a lysozyme-like one and another substance) are considered to occur in Myriapoda. PMID:2273286

  15. Human Gut Bacteria Are Sensitive to Melatonin and Express Endogenous Circadian Rhythmicity

    PubMed Central

    Paulose, Jiffin K.; Wright, John M.; Patel, Akruti G; Cassone, Vincent M.

    2016-01-01

    Circadian rhythms are fundamental properties of most eukaryotes, but evidence of biological clocks that drive these rhythms in prokaryotes has been restricted to Cyanobacteria. In vertebrates, the gastrointestinal system expresses circadian patterns of gene expression, motility and secretion in vivo and in vitro, and recent studies suggest that the enteric microbiome is regulated by the host’s circadian clock. However, it is not clear how the host’s clock regulates the microbiome. Here, we demonstrate at least one species of commensal bacterium from the human gastrointestinal system, Enterobacter aerogenes, is sensitive to the neurohormone melatonin, which is secreted into the gastrointestinal lumen, and expresses circadian patterns of swarming and motility. Melatonin specifically increases the magnitude of swarming in cultures of E. aerogenes, but not in Escherichia coli or Klebsiella pneumoniae. The swarming appears to occur daily, and transformation of E. aerogenes with a flagellar motor-protein driven lux plasmid confirms a temperature-compensated circadian rhythm of luciferase activity, which is synchronized in the presence of melatonin. Altogether, these data demonstrate a circadian clock in a non-cyanobacterial prokaryote and suggest the human circadian system may regulate its microbiome through the entrainment of bacterial clocks. PMID:26751389

  16. Differentiation of Aerobacter-Klebsiella isolated from sugarcane.

    PubMed

    Nunez, W J; Colmer, A R

    1968-12-01

    Three hundred and eighty-four isolates were obtained in the completed test portion of the most probable number determinations of coliforms in sugarcane sources. Of these isolates, 88% were of the (- - + +) indole, methyl red, Voges-Proskauer, citrate (IMViC) type and were identified as Aerobacter aerogenes according to the protocol of the American Public Health Association (1). Employing 359 of these cultures, a comparative biochemical, serological, and pathogenicity study was carried out with Klebsiella pneumoniae CDC no. 2211-66 type 9. More than 86% of the organisms tested gave biochemical reactions typical of K. pneumoniae. Of the other isolates, 2% were Enterobacter aerogenes, and the remaining 12% were identified as atypical, nonmotile IMViC types. Comparable agglutination titers were also observed between A. aerogenes and the CDC strain of K. pneumoniae when several randomly selected sugarcane strains were reacted with prepared K. pneumoniae whole cell antiserum. Neither the K. pneumoniae reference organism nor selected sugarcane isolates displayed pathogenicity for mice. On the basis of all the analyses performed, it was suggested that such organisms be classified as K. pneumoniae. PMID:5726159

  17. OEM--a new medium for rapid isolation of onion-pathogenic and onion-associated bacteria.

    PubMed

    Zaid, Ali M; Bonasera, Jean M; Beer, Steven V

    2012-12-01

    Onions (Allium cepa L.) are plagued by a number of bacterial pathogens including Pantoea ananatis, P. agglomerans, Burkholderia cepacia, Enterobacter cloacae, Pectobacterium carotovorum subsp. carotovorum, Xanthomonas axonopodis pv. axonopodis and several Pseudomonas spp. We developed a semi-selective medium, termed onion extract medium (OEM), to selectively and rapidly isolate bacteria pathogenic to and associated with onions and onion-related samples including bulbs, seeds, sets, transplant seedlings, soil and water. Most strains of interest grow sufficiently on OEM in 24h at 28°C for tentative identification based on colony morphology, facilitating further characterization by microbiological and/or molecular means. PMID:23041494

  18. Bacterial tracheobronchitis. A rare cause of adult airway stenosis.

    PubMed

    Kadowaki, Toru; Hamada, Hironobu; Fujiwara, Ai; Miyoshi, Seigo; Hamaguchi, Naohiko; Ito, Ryoji; Higaki, Jitsuo

    2009-11-01

    Bacterial tracheobronchitis is a rare cause of airway stenosis in adults. This report describes a 73-year-old woman with a recent history of polysialadenitis, who presented with severe airway obstruction due to infection and stenosis of tracheal and bronchial tissue. Tissue culture of the bronchial mucosa showed growth of methicillin resistant Staphylococcus epidermidis (MRSE). Sputum culture showed growth of MRSE, Pseudomonas aeruginosa, Enterobacter cloacae and Enterococcus faecalis; the same organisms were cultured from the salivary glands. Tracheostomy and antibiotic therapy were effective in controlling the disease. PMID:19818053

  19. A TLC bioautographic assay for the detection of nitrofurantoin resistance reversal compound.

    PubMed

    Shahverdi, Ahmad R; Abdolpour, Farid; Monsef-Esfahani, Hamid R; Farsam, Hasan

    2007-05-01

    A simple TLC bioautographic method was developed for detection of antibiotic resistance reversal agents. In this study, the retention factor values of the components of some essential oils not previously shown to have any antibacterial activity were evaluated on nitrofurantoin supplemented agar media. The active component of Artemisia annua, Artemisia dracunculus and Eucalyptus globulus essential oils was piperitone which increased the antibacterial activity of nitrofurantoin against Enterobacter cloacae. Piperitone was not detected in the essential oil of Humulus lupulus and we could not observe any clear areas in this bioautographic method. PMID:17140862

  20. Hydrazine degradation and its effect on microbial activity in soil

    SciTech Connect

    Ou, L.T.; Street, J.J.

    1987-01-01

    Considerable information has been accumulated on the toxicity of hydrazine to soil bacterial cultures and on the degradation of hydrazne by soil bacterial cultures. The activities of the autotrophic nitrifiers Nitrosomonas and Nitrobacter and of denitrifying bacteria, and the growth of Enterobacter cloacae, were all inhibited by hydrazine. An enzyme system has been found in heterotrophic N/sub 2/-fixing bacteria capable of degrading hydrazine. Information concerning the effect of hydrazine on microbial activity in soils is not available, however. Accidental spills to soil can occur during transportation and storage. Therefore, this study was initiated to determine degradation rates of hydrazine in soils and its effect on soil microbial activity.

  1. Outbreak Caused by Enterobacteriaceae Harboring NDM-1 Metallo-β-Lactamase Carried in an IncFII Plasmid in a Tertiary Care Hospital in Mexico City

    PubMed Central

    Torres-González, Pedro; Bobadilla-del Valle, Miriam; Tovar-Calderón, Estrella; Leal-Vega, Francisco; Hernández-Cruz, Araceli; Martínez-Gamboa, Areli; Niembro-Ortega, María Dolores; Sifuentes-Osornio, José

    2015-01-01

    Carbapenem-resistant Enterobacteriaceae carrying New Delhi metallo-β-lactamase 1 (NDM-1) have rarely been reported in Latin America. We report of an outbreak caused by a blaNDM-1-harboring plasmid spread through different bacterial species, including Escherichia coli (ST617) and Enterobacter cloacae (ST182) isolates from the same patient and three Klebsiella pneumoniae isolates (ST22) derived from three epidemiologically related patients. IncFII plasmids were found in all strains. Measures to control the outbreak were applied successfully. PMID:26282410

  2. Cloning and nucleotide sequence of the gene encoding the Ecal DNA methyltransferase.

    PubMed Central

    Brenner, V; Venetianer, P; Kiss, A

    1990-01-01

    The gene coding for the GGTNACC specific Ecal DNA methyltransferase (M.Ecal) has been cloned in E. coli from Enterobacter cloacae and its nucleotide sequence has been determined. The ecalM gene codes for a protein of 452 amino acids (Mr: 51,111). It was determined that M.Ecal is an adenine methyltransferase. M.Ecal shows limited amino acid sequence similarity to other adenine methyltransferases. A clone that expresses Ecal methyltransferase at high level was constructed. Images PMID:2183182

  3. Spread of Plasmids Carrying Multiple GES Variants.

    PubMed

    Cuzon, Gaelle; Bogaerts, Pierre; Bauraing, Caroline; Huang, Te-Din; Bonnin, Rémy A; Glupczynski, Youri; Naas, Thierry

    2016-08-01

    Five GES-producing Enterobacteriaceae isolates that displayed an extended-spectrum β-lactamase (ESBL) phenotype harbored two GES variants: GES-7 ESBL and GES-6 carbapenemase. In all isolates, the two GES alleles were located on the same integron that was inserted into an 80-kb IncM1 self-conjugative plasmid. Whole-genome sequencing suggested in vivo horizontal gene transfer of the plasmid along with clonal diffusion of Enterobacter cloacae To our knowledge, this is the first description in Europe of clustered Enterobacteriaceae isolates carrying two GES β-lactamases, of which one has extended activity toward carbapenems. PMID:27216071

  4. Prevention of Biofilm Colonization by Gram-Negative Bacteria on Minocycline-Rifampin-Impregnated Catheters Sequentially Coated with Chlorhexidine

    PubMed Central

    Jamal, Mohamed A.; Rosenblatt, Joel S.; Hachem, Ray Y.; Ying, Jiang; Pravinkumar, Egbert; Nates, Joseph L.; Chaftari, Anne-Marie P.

    2014-01-01

    Resistant Gram-negative bacteria are increasing central-line-associated bloodstream infection threats. To better combat this, chlorhexidine (CHX) was added to minocycline-rifampin (M/R) catheters. The in vitro antimicrobial activity of CHX-M/R catheters against multidrug resistant, Gram-negative Acinetobacter baumannii, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia was tested. M/R and CHX-silver sulfadiazine (CHX/SS) catheters were used as comparators. The novel CHX-M/R catheters were significantly more effective (P < 0.0001) than CHX/SS or M/R catheters in preventing biofilm colonization and showed better antimicrobial durability. PMID:24165191

  5. Type II Hydride Transferases from Different Microorganisms Yield Nitrite and Diarylamines from Polynitroaromatic Compounds▿ †

    PubMed Central

    van Dillewijn, Pieter; Wittich, Rolf-Michael; Caballero, Antonio; Ramos, Juan-Luis

    2008-01-01

    Homogenous preparations of XenB of Pseudomonas putida, pentaerythritol tetranitrate reductase of Enterobacter cloacae, and N-ethylmaleimide reductase of Escherichia coli, all type II hydride transferases of the Old Yellow Enzyme family of flavoproteins, are shown to reduce the polynitroaromatic compound 2,4,6-trinitrotoluene (TNT). The reduction of this compound yields hydroxylaminodinitrotoluenes and Meisenheimer dihydride complexes, which, upon condensation, yield stoichiometric amounts of nitrite and diarylamines, implying that type II hydride transferases are responsible for TNT denitration, a process with important environmental implications for TNT remediation. PMID:18791007

  6. Bacteremia and vegetative endocarditis associated with a heart murmur in a blue-and-gold macaw.

    PubMed

    Isaza, R; Buergelt, C; Kollias, G V

    1992-01-01

    A 6-year-old male blue-and-gold macaw (Ara ararauna) was presented with severe weakness, anorexia, and weight loss of 2 weeks duration. Cardiac auscultation revealed a soft systolic murmur. Blood cultures collected both antemortem and postmortem yielded pure isolates of Enterobacter cloacae. At necropsy, vegetative endocarditis was found involving the left atrioventricular valve. Microscopically, the lesion on the valve was characterized by a mixture of necrotic material, colonies of gram-negative bacteria, fibrosis, and inflammatory infiltrate consisting primarily of heterophils. PMID:1485868

  7. The Carbapenem Inactivation Method (CIM), a Simple and Low-Cost Alternative for the Carba NP Test to Assess Phenotypic Carbapenemase Activity in Gram-Negative Rods

    PubMed Central

    van der Zwaluw, Kim; de Haan, Angela; Pluister, Gerlinde N.; Bootsma, Hester J.; de Neeling, Albert J.; Schouls, Leo M.

    2015-01-01

    A new phenotypic test, called the Carbapenem Inactivation Method (CIM), was developed to detect carbapenemase activity in Gram-negative rods within eight hours. This method showed high concordance with results obtained by PCR to detect genes coding for the carbapenemases KPC, NDM, OXA-48, VIM, IMP and OXA-23. It allows reliable detection of carbapenemase activity encoded by various genes in species of Enterobacteriaceae (e.g., Klebsiella pneumoniae, Escherichia coli and Enterobacter cloacae), but also in non-fermenters Pseudomonas aeruginosa and Acinetobacter baumannii. The CIM was shown to be a cost-effective and highly robust phenotypic screening method that can reliably detect carbapenemase activity. PMID:25798828

  8. Bacteria colonizing root nodules of wild legumes exhibit virulence-associated properties of mammalian pathogens.

    PubMed

    Muresu, Rosella; Maddau, Giuseppe; Delogu, Giuseppe; Cappuccinelli, Piero; Squartini, Andrea

    2010-02-01

    Bacteria not proficient in nitrogen fixing symbiosis were proven able to invade root nodules of three wild legumes of the genus Hedysarum in Algeria and to be multiplying in these in place of the natural rhizobium symbionts. The involved species featured taxa known as human pathogens including: Enterobacter cloacae, Enterobacter kobei, Escherichia vulneris, Pantoea agglomerans and Leclercia adecarboxylata. A direct screening of the phenotypic determinants of virulence using human cultured cells tested positive for the traits of cytotoxicity, vital stain exclusion and adhesion to epithelia. Antibiogram analyses revealed also a complex pattern of multiple antibiotic resistances. The data suggest that legume root nodules can be a site of survival and of active multiplication for populations of mammalian pathogens, which could thus alternate between the target animal and a number of neutral plant hosts. The worldwide distribution of as yet uninvestigated legumes raises the concern that these represent a general niche that could enhance the hazards posed by microorganisms of clinical nature. PMID:19916054

  9. Domiciliary cockroaches found in restaurants in five zones of Kuala Lumpur Federal Territory, peninsular Malaysia.

    PubMed

    Jeffery, J; Sulaiman, S; Oothuman, P; Vellayan, S; Zainol-Ariffin, P; Paramaswaran, S; Razak, A; Muslimin, M; Kamil-Ali, O B; Rohela, M; Abdul-Aziz, N M

    2012-03-01

    The following domiciliary cockroaches were collected from restaurants in five zones of Kuala Lumpur Federal Territory, Malaysia using 1L glass beaker traps baited with ground mouse-pellets: Periplaneta americana (Linnaeus) (n = 820), Periplaneta brunnea Burmeister (n = 46), Blattella germanica (Linnaeus) (n = 12504), Supella longipalpa (Fabricius) (n = 321), Symploce pallens Stephens (n = 29) and Neostylopyga rhombifolia (Stoll) (n = 5). The following bacteria were isolated from 10 cockroach specimens: Enterobacter cloacae, Klebsiella pneumoniae ssp. pneumoniae, Klebsiella pneumoniae ssp. rhinoscleromatis and Serratia liquefaciens from 5 B. germanica; Acinetobacter calcoaceticus var. anitratus, Citrobacter diversus/amalonaticus, Escherichia vulneris and K.p. pneumoniae from 3 P. brunnea; and Citrobacter freundii, Enterobacter agglomerans 4, Escherichia adecarboxylate, E. vulneris, K. p. pneumonia, K. p. rhinoscleromatis and Proteus vulgeris from 2 P. americana. PMID:22543619

  10. Bacterial strains isolated from eggs and their resistance to currently used antibiotics: is there a health hazard for consumers?

    PubMed

    Papadopoulou, C; Dimitriou, D; Levidiotou, S; Gessouli, H; Panagiou, A; Golegou, S; Antoniades, G

    1997-01-01

    In order to study the putative transfer of antibiotic resistance from poultry to humans, hens' eggs were examined for the presence of various pathogens. Staphylococcus, Enterobacter, Escherichia, Proteus and Pseudomonas spp. were the most frequently isolated genera. Sensitivity tests, performed with the Kirby-Bauer technique, showed the presence of resistant strains of Staphylococcus aureus (to penicillin-G, tetracycline, erythromycin, clindamycin, cefalosporins, oxacillin, gentamycin, chloramphenicol and tobramycin), Enterococcus faecalis (to ampicillin, ciprofloxacin, clindamycin, gentamycin and tetracyclin), Escherichia coli (to tetracycline, erythromycin, ampicillin and cefalosporins), Enterobacter cloacae (to ampicillin, amoxycillin plus clavunalic acid, erythromycin and tetracycline), Pseudomonas stutzeri (to erythromycin and chlorampenicol) and Citrobacter freundii (to ampicillin, amoxycillin plus clavunalic acid, cefalosporins and co-trimoxazole). PMID:9023039

  11. Evaluation of antimicrobial activity of the stem bark of Cylicodiscus gabunensis (Mimosaceae).

    PubMed

    Kouitcheu Mabeku, Laure B; Kouam, J; Penlap, Beng V; Ngadjui, Bonaventure T; Fomum, Z T; Etoa, F X

    2006-01-01

    Ethyl acetate (EA) extract of the stem bark of Cylicodiscus gabunensis (CG) was analysed phytochemically and evaluated for its antimicrobial activity against 17 pathogenic species isolated from patient: Escherichia coli, Klebsiella pneumoniae, Shigella dysenteriae, Shigella flexneri, Morganella morganii, Proteus vulgaris, Proteus mirabilis, Salmonella typhi, Citrobacter freundii, Enterobacter cloacae, Enterobacter agglomerans, Staphylococcus aureus, Streptococcus feacalis, Pseudomonas aeruginosa, Bacillus cereus T, Candida albicans and Candida glabrata. Flavonoids, saponins, tannins, polyphenols, coumarins, triterpenes and/or sterols and reducing sugars were detected in the (EA) extract of CG. The best MIC and MBC values for the microorganisms sensitive to the extract were 0.00078 and 0.00315 mg/ml respectively. The greater and remarkable antimicrobial activity of the (EA) extract of CG was recorded with Staphylococcus aureus, Proteus vulgaris and Bacillus cereus T. These results provide a rationalization for the traditional use of this plant for the treatment of infectious diseases. PMID:20162076

  12. Monoterpenes as nitrofurantoin resistance modulating agents: minimal structural requirements, molecular dynamics simulations, and the effect of piperitone on the emergence of nitrofurantoin resistance in Enterobacteriaceae.

    PubMed

    Shahverdi, Ahmad R; Mirzaie, Sako; Rafii, Fatemeh; Kakavand, Marjan; Foroumadi, Alireza

    2015-08-01

    The effects of different monoterpenes and 2-cyclohexen-1-one on the antibacterial activity of nitrofurantoin against resistant Enterobacter cloacae, were compared and the minimal structural component of monoterpene required for the highest level of resistance-modulating activity was determined. Subinhibitory concentrations of all compounds tested enhanced the antibacterial activity of nitrofurantoin against E. cloacae to different extents. The highest synergistic effect was observed for the monoterpenes, like piperitone, which contained a conjugated ketone and C=C bond in their carbon ring structure. Piperitone also suppressed the emergence of nitrofurantoin-resistant strains of Enterobacteriaceae that were mutagenized by ethyl methanesulfonate. The modes of interaction of carvone, piperitone, and an enzyme inhibitor, benzoate, with nitroreductase were investigated by molecular docking and molecular dynamic (MD) simulation for 20 ns. MD simulation supported greater stability of the benzoate and monoterpene-nitroreductase (NR) complexes than of free NR. The results of this investigation are promising for the synthesis of more effective lead compounds to enhance the antibacterial activity of nitro drugs against resistant Enterobacter strains. PMID:26174760

  13. In-Use Contamination of Intravenous Infusion Fluid

    PubMed Central

    Maki, Dennis G.; Anderson, Roger L.; Shulman, Jonas A.

    1974-01-01

    During the 1970 to 1971 nationwide epidemic of septicemias caused by Enterobacter cloacae and Enterobacter agglomerans traced to intrinsic contamination of Abbott intravenous infusion products, 94 infusion systems manufactured by Baxter Laboratories were studied microbiologically and epidemiologically during hospital use. Intravenous fluid from 10 systems (11%) contained microorganisms, usually Staphylococcus or Bacillus species; one infusion was heavily contaminated with Klebsiella pneumoniae. No national epidemic organisms, E. cloacae or E. agglomerans (formerly Erwinia), were recovered, suggesting that during this period frequent contamination with these organisms was unique to Abbott's infusion products. Contamination in this study appeared to be extrinsic in origin (introduced during clinical use) and related to the duration of continuous intravenous therapy. Nine of 61 systems (15%) that had been used longer than 48 h were contaminated, whereas only 1 of 33 used less than 48 h (3%) contained microorganisms. This study and the recent national outbreak indicate that contamination of infusion fluid, both from intrinsic and extrinsic sources, must be recognized as an additional risk of intravenous therapy; however, a once-daily replacement of the delivery apparatus can significantly diminish this hazard. PMID:4613269

  14. Antibacterial activity of Zuccagnia punctata Cav. ethanolic extracts.

    PubMed

    Zampini, Iris C; Vattuone, Marta A; Isla, Maria I

    2005-12-01

    The present study was conducted to investigate antibacterial activity of Zuccagnia punctata ethanolic extract against 47 strains of antibiotic-resistant Gram-negative bacteria and to identify bioactive compounds. Inhibition of bacterial growth was investigated using agar diffusion, agar macrodilution, broth microdilution and bioautographic methods. Zuccagnia punctata extract was active against all assayed bacteria (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter cloacae, Serratia marcescens, Morganella morganii, Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia) with minimal inhibitory concentration (MIC) values ranging from 25 to 200 microg/mL. Minimal bactericidal concentration (MBC) values were identical or two-fold higher than the corresponding MIC values. Contact bioautography, indicated that Zuccagnia punctata extracts possess one major antibacterial component against Pseudomonas aeruginosa and at least three components against. Klebsiella pneumoniae and Escherichia coli. Activity-guided fractionation of 1he ethanol extract on a silica gel column yielded a compound (2',4'-dihydroxychalcone), which exhibited strong antibacterial activity with MIC values between 0.10 and 1.00 microg/mL for Proteus mirabilis, Enterobacter cloacae, Serratia marcescens, Morganella morganii, Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia. These values are lower than imipenem (0.25-16 microg/mL). Zuccagnia punctata might provide promising therapeutic agents against infections with multi-resistant Gram-negative bacteria. PMID:16137849

  15. Screening for anti-infective properties of several medicinal plants of the Mauritians flora.

    PubMed

    Rangasamy, Oumadevi; Raoelison, Guy; Rakotoniriana, Francisco E; Cheuk, Kiban; Urverg-Ratsimamanga, Suzanne; Quetin-Leclercq, Joelle; Gurib-Fakim, Ameenah; Subratty, Anwar Hussein

    2007-01-19

    Several plants of the Mauritian flora alleged to possess anti-infective properties were studied against different strains of pathogenic bacteria and fungi. The grounded dried plant materials were extracted with different extractants and screened for anti-microbial activity using the disk diffusion and the micro-dilution techniques. Preliminary screening revealed that the methanol extracts were most active. Salmonella enteritidis, Enterobacter cloacae and Bacillus subtilis were the three test organisms, which were found to be susceptible to all the crude methanolic extracts of the different plants investigated (100% susceptibility), followed by Escherichia coli (57.1%) and Pseudomonas aeruginosa (57.1%), and Staphylococcus aureus (28.6%). The lowest minimum inhibitory concentration recorded for the different crude methanol extracts against Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, Enterobacter cloacae, Bacillus subtilis and the mould fungus Candida albicans were 500, 1000, 125, 250, 1000 and 125 micro g/ml, respectively. Bioautography using Cladosporium cucumerinum revealed that dichloromethane (DCM) extracts had the highest activity against the phytopathogenic fungus. It was also noted that the DCM extracts of Michelia champaca and Antidesma madagascariense yielded the maximum number of growth inhibiting compounds against Cladosporium cucumerinum. Activity of the different crude extracts was also investigated against several phytopathogenic filamentous fungi, Colletotrichum glocosporoides, Rhizoctonia solani, Sclerotinia sclerotium, Guignardia sp. and Fusarium oxysporum. It was found that crude hexane extracts as well as crude DCM extracts exhibited marked activity against several strains of fungi, especially Colletotrichum glocosporoides, Sclerotinia sclerotium and Guignardia sp. PMID:17011733

  16. Prevalence of silver resistance in bacteria isolated from diabetic foot ulcers and efficacy of silver-containing wound dressings.

    PubMed

    Percival, Steven L; Woods, Emma; Nutekpor, Moses; Bowler, Phil; Radford, Alan; Cochrane, Christine

    2008-03-01

    Silver dressings are used to manage wounds at risk of infection or locally infected. This in vitro study was conducted to assess the prevalence of silver resistance genes in 112 bacterial isolates obtained from the diabetic foot ulcers of patients attending the Diabetic Foot Clinic at Tameside General Hospital, UK. Using polymerase chain reaction to screen for three silver-resistance transcriptional units--silE, silS and silP--two silver-resistant bacteria were identified; both are strains of Enterobacter cloacae, an organism rarely implicated as a primary pathogen in chronic wounds. No recognized wound pathogens (Staphylococcus aureus-24 isolates and Pseudomonas aeruginosa-nine isolates) were found to contain silver-resistant genes. Analysis of the efficacy of silver-containing dressings on the silver-resistant strains of Enterobacter cloacae using confocal laser microscopy showed that, despite evidence of genetic resistance to silver, all strains were killed following a maximum of 48 hours of exposure to the dressings. Results suggest that presence of silver resistance genes is rare and that genetic resistance does not necessarily translate to phenotypic resistance to silver. While silver resistance in wound care should be monitored, the threat of widespread resistance is low and silver-containing dressings remain an extremely important tool in managing wound infection. PMID:18382046

  17. Two Novel Algicidal Isolates Kill Chlorella pyrenoidosa by Inhibiting their Host Antioxidase Activities.

    PubMed

    Liao, Chunli; Liu, Xiaobo; Liu, Ruifang; Shan, Linna

    2015-09-01

    In the biocontrol of harmful algal blooms, there has been considerable interest about the role of algicidal bacteria in algicidal activity. In this experiment, two novel algicidal bacteria (strains NP23 and AM11) against Chlorella pyrenoidosa were isolated from the Baiguishan reservoir in China. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains NP23 and AM11 belonged to Enterobacter cloacae and Gibberella moniliformis, respectively. To further understand the algicidal activities, five parameters including the chlorophyll a content, cell survival rate, superoxide dismutase (SOD) peroxide dismutase (POD), and catalase (CAT) were tested in the C. pyrenoidosa cells after inoculation with the algicidal bacteria Enterobacter cloacae NP23 and Gibberella moniliformis AM11. As a result, the growth of the treated C. pyrenoidosa was significantly restrained with a great decline of chlorophyll a content. Meanwhile, three antioxidase activities of the treated C. pyrenoidosa were initially stimulated from day 1 to day 3 but then dramatically inhibited at low level. These results induced that the oxidative imbalance (i.e., inhibition of antioxidase activities) caused by algicidal bacteria could be the killing agent of the C. pyrenoidosa cells. PMID:26194712

  18. Characterization of carbon-sulfur bond cleavage by axenic and mixed cultures of Rhodococcus rhodochrous IGTS8

    SciTech Connect

    Kayser, K.J.; Bielaga, B.A.; Jackowski, K.; Oduson, O.; Kilbane, J. II

    1992-12-31

    Growth assays reveal that Rhodococcus rhodochrous IGTS8 can utilize a wide range of organosulfur compounds as the sole source of sulfur. Compounds that are utilized include thiophenes, sulfides, disulfides, mercaptans, sulfoxides, and sulfones. None of the organosulfur compounds tested can serve as a carbon source. A convenient spectrophotometric assay (Gibbs assay) based on the chromogenic reaction of 2,6-dichloroquinone-4-chloroimide with aromatic hydroxyl groups was developed and used in conjunction with GC/MS analysis to examine the kinetics of carbon-sulfur bond cleavage by axenic and mixed cell cultures of Rhodococcus rhodochrous IGTS8. The desulfurization trait is expressed at uniform levels during the mid-exponential phase, reaches a maximum during idiophase, and then declines in stationary-phase cells. Desulfurization rates for dibenzothiophene (DBT) range from 8 to 15 {mu}M of DBT/10{sup 12} cells/hour. Mixtures of genetically marked Rhodococcus rhodochrous IGTS8 and an organisms incapable of cleaning carbon-sulfur bonds in relevant test compounds, Enterobacter cloacae, were prepared in ratios that varied over six orders of magnitude. Growth studies revealed that Enterobacter cloacae was able to gain access to sulfur liberated from organosulfur compounds by IGTS8; however, cell-to-cell contact was required. These data also indicate that the desulfurization activity of IGTS8 cells in mixed cultures may be as much as 200-fold higher than in axenic cultures.

  19. Molecular characterization of class b carbapenemases in advanced stage of dissemination and emergence of class d carbapenemases in Enterobacteriaceae from Croatia.

    PubMed

    Bedenić, Branka; Sardelić, Sanda; Luxner, Josefa; Bošnjak, Zrinka; Varda-Brkić, Dijana; Lukić-Grlić, Amarela; Mareković, Ivana; Frančula-Zaninović, Sonja; Krilanović, Marija; Šijak, Dorotea; Grisold, Andrea; Zarfel, Gernot

    2016-09-01

    Carbapenemases involved in acquired carbapenem resistance in Enterobacteriaceae belong to Ambler class A serin β-lactamases, class B metallo-β-lactamases (MBL) or class D OXA-48-like β-lactamases. The aim of the present study was to analyse the molecular epidemiology and the mechanisms and routes of spread of class B and class D carbapenemases in Croatia. In total 68 isolates were analyzed. Antibiotic susceptibility was determined by broth microdilution method. PCR was used to detect antibiotic-resistance genes. Genotyping was performed by rep-PCR and MLST. Sixty-five isolates were found to harbour VIM-1 carbapenemase, seven of which were positive also for NDM-1, while two strains harboured only NDM-1. OXA-48 was detected in three isolates, two of which coproduced VIM-1. Thirty-six strains possessed additional CTX-M-15 β-lactamase whereas 64 were positive for TEM-1. CMY was found in 18 Citrobacter freundii isolates and DHA-1 in one Enterobacter cloacae isolate. Four different plasmid-incompatibility groups were found: A/C, L/M, N and FIIAs. Unlike C. freundii and E. cloacae, Klebsiella pneumoniae showed high diversity of rep-PCR patterns. E. cloacae and C. freundii predominantly belonged to one large clone which was allocated to ST105 and ST24, respectively. Three different types of carbapenemases were identified showing the complexity of CRE in Croatia. PMID:27174090

  20. Preflight and postflight microbiological results from 25 space shuttle crews

    NASA Technical Reports Server (NTRS)

    Pierson, Duane L.; Bassinger, Virginia J.; Molina, Thomas C.; Gunter, Emelie G.; Groves, Theron O.; Cioletti, Louis J.; Mishra, S. K.

    1993-01-01

    Clinical-microbiological investigations are an important aspect of the crew health stabilization program. To ensure that space crews have neither active nor latent infections, clinical specimens, including throat and nasal swabs and urine samples, are collected at 10 days (L-10) and 2days (L-2) before launch, and immediately after landing (L+0). All samples are examined for the presence of bacteria and fungi. In addition, fecal samples are collected at L-10 and examined for bacteria, fungi and parasites. This paper describes clinical-microbiological findings from 144 astronauts participating in 25 Space Shuttle missions spanning Space Transportation System (STS)-26 to STS-50. The spectrum of microbiological findings from the specimens included 25 bacterial and 11 fungal species. Among the bacteria isolated most frequently were Staphylococcus aureus, Enterobacter aerogenes, Enterococcus faecalis, Escherichia coli, Proteus mirabilis and Streptococcus agalactiae. Candida albicans was the most frequently isolated fungal pathogen.

  1. Phagocytic and chemiluminescent responses of mouse peritoneal macrophages to living and killed Salmonella typhimurium and other bacteria.

    PubMed Central

    Tomita, T; Blumenstock, E; Kanegasaki, S

    1981-01-01

    In the presence of luminol, resident as well as thioglycolate-induced and immunized macrophages emitted chemiluminescence more efficiently when the cells were exposed to living Salmonella typhimurium than when they were exposed to the same bacterium killed by ultraviolet light or heat. This phenomenon was observed whether or not the bacterium was opsonized. The different response to living and killed bacteria was also found with Escherichia coli, Pseudomonas aeruginosa, Proteus morganii, and Enterobacter aerogenes, but not with Shigella sonnei, Klebsiella pneumoniae, and Propionibacterium acnes. The results suggest that macrophages respond better to living, motile bacteria than to nonmotile or killed bacteria. The experimental results obtained with motility mutants of S. typhimurium, E. coli, and P. aeruginosa confirm that macrophages exposed to the motile bacteria emit chemiluminescence more efficiently and ingest the motile bacteria at a much faster rate than the nonmotile bacteria. Images PMID:6788707

  2. In situ studies of microbial inactivation during high pressure processing

    NASA Astrophysics Data System (ADS)

    Maldonado, Jose Antonio; Schaffner, Donald W.; Cuitiño, Alberto M.; Karwe, Mukund V.

    2016-01-01

    High pressure processing (HPP) has been shown to reduce microbial concentration in foods. The mechanisms of microbial inactivation by HPP have been associated with damage to cell membranes. The real-time response of bacteria to HPP was measured to elucidate the mechanisms of inactivation, which can aid in designing more effective processes. Different pressure cycling conditions were used to expose Enterobacter aerogenes cells to HPP. Propidium iodide (PI) was used as a probe, which fluoresces after penetrating cells with damaged membranes and binding with nucleic acids. A HPP vessel with sapphire windows was used for measuring fluorescence in situ. Membrane damage was detected during pressurization and hold time, but not during depressurization. The drop in fluorescence was larger than expected after pressure cycles at higher pressure and longer times. This indicated possible reversible disassociation of ribosomes resulting in additional binding of PI to exposed RNA under pressure and its release after depressurization.

  3. Antibacterial and preliminary phytochemical and physico-chemical analysis of Eucalyptus citriodora Hk leaf.

    PubMed

    Vaghasiya, Y; Nair, R; Chanda, S

    2008-06-15

    The present communication deals with some studies on the antibacterial, physico-chemical and phytochemical parameters of different extracts of Eucalyptus citriodora leaf. The antibacterial study was performed using the agar ditch method on some clinically important bacteria, namely Pseudomonas pseudoalcaligenes, Proteus vulgaris, Citrobacter freundii, Staphylococcus subflava, Bacillus megaterium, and Enterobacter aerogenes. Physico-chemical parameters namely water, methanol, 1,4-dioxane, DMF, acetone soluble extractives, total ash, melting point, and pH were determined according to pharmacopoeial procedures. Methanol gave the maximum extract while it was minimum in water. Phytochemical parameters were screened for alkaloids, tannins, cardiac glycosides, saponins, steroids and flavonoids. Tannins and flavonoids gave positive results, while steroids and glycosides were absent. The most susceptible bacteria was C. freundii, while the most resistant was P. vulgaris. PMID:18569717

  4. Pleural effusion Due to Streptococcus milleri: Case descriptions.

    PubMed

    Madrid-Carbajal, Claudia Janeth; Molinos, Luis; García-Clemente, Marta; Pando-Sandoval, Ana; Fleites, Ana; Casan-Clarà, Pere

    2014-09-01

    In this study we analyzed the characteristics of patients with pleural effusion secondary to Streptococcus milleri studied retrospectively between January and March 2013 and found seven patients with a mean age of 60 years, 43% of which were smokers and 57% with a drinking habit. The most common associated factors were alcoholism, previous pneumonia and diabetes. Other bacteria were identified as Enterobacter aerogenes, Bacteroides and Prevotella intermedia capillosus in two patients. The mean duration of antibiotic therapy was 28 days; six patients underwent pleural drainage by chest tube and one patient needed surgery due to poor clinical progress. The mean duration of hospitalization was 30 days with satisfactory outcome in all cases, despite some changes in residual function. PMID:24439468

  5. Screening of antibacterial potentials of some medicinal plants from Melghat forest in India.

    PubMed

    Tambekar, D H; Khante, B S; Chandak, B R; Titare, A S; Boralkar, S S; Aghadte, S N

    2009-01-01

    Cyperus rotundus, Caesalpinia bonducella, Tinospora cordifolia, Gardenia gummifera, Ailanthus excelsa, Acacia arabica, Embelia ribes and Ventilago maderspatana from Melghat forest were screened for their antibacterial potential against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Proteus vulgaris, Salmonella typhi, Shigella flexneri, Salmonella paratyphi, Salmonella typhimurium, Pseudomonas aeruginosa, Enterobacter aerogenes by disc diffusion method. Out of these medicinal plants Caesalpinia bonducella, Gardenia gummifera and Acacia arabica showed remarkable antibacterial potential. The phytochemical analysis had showed the presence of Cardiac glycosides in all extracts (aqueous, acetone, ethanol and methanol) of Acacia arabica, Gardenia gummifera and ethanol, methanol extracts of Caesalpinia bonducella. Flavonoids were present in Gardenia gummifera, Ailanthus excelsa and acetone, methanol extracts of Acacia Arabica. Tannins and phenolic were present in Cyperus rotundus, Embelia ribes, and organic extracts of Ventilago maderspatana. PMID:20448847

  6. Differentiation of bacterial colonies and temporal growth patterns using hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Mehrübeoglu, Mehrube; Buck, Gregory W.; Livingston, Daniel W.

    2014-09-01

    Detection and identification of bacteria are important for health and safety. Hyperspectral imaging offers the potential to capture unique spectral patterns and spatial information from bacteria which can then be used to detect and differentiate bacterial species. Here, hyperspectral imaging has been used to characterize different bacterial colonies and investigate their growth over time. Six bacterial species (Pseudomonas fluorescens, Escherichia coli, Serratia marcescens, Salmonella enterica, Staphylococcus aureus, Enterobacter aerogenes) were grown on tryptic soy agar plates. Hyperspectral data were acquired immediately after, 24 hours after, and 96 hours after incubation. Spectral signatures from bacterial colonies demonstrated repeatable measurements for five out of six species. Spatial variations as well as changes in spectral signatures were observed across temporal measurements within and among species at multiple wavelengths due to strengthening or weakening reflectance signals from growing bacterial colonies based on their pigmentation. Between-class differences and within-class similarities were the most prominent in hyperspectral data collected 96 hours after incubation.

  7. (1)H NMR spectroscopy in the diagnosis of Pseudomonas aeruginosa-induced urinary tract infection.

    PubMed

    Gupta, Ashish; Dwivedi, Mayank; Nagana Gowda, G A; Ayyagari, Archana; Mahdi, A A; Bhandari, M; Khetrapal, C L

    2005-08-01

    The utility of (1)H NMR spectroscopy is suggested and demonstrated for the diagnosis of Pseudomonas aeruginosa in urinary tract infection (UTI). The specific property of P. aeruginosa of metabolizing nicotinic acid to 6-hydroxynicotinic acid (6-OHNA) is exploited. The quantity of 6-OHNA produced correlates well with the viable bacterial count. Other common bacteria causing UTI such as Escherichia coli, Klebsiella pneumonia, Enterobacter aerogenes, Acinetobacter baumanii, Proteus mirabilis, Citrobacter frundii, Enterococcus faecalis, Streptococcus gp B and Staphylococcus aureus do not metabolize nicotinic acid under similar conditions. The method provides a single-step documentation of P. aeruginosa qualitatively as well as quantitatively. The NMR method is demonstrated on urine samples from 30 patients with UTI caused by P. aeruginosa. PMID:15759292

  8. Safety, efficacy and utility of methods of transferring adhesive and cohesive Escherichia coli cells to microplates to avoid aerosols

    PubMed Central

    Ericksen, Bryan

    2015-01-01

    The virtual colony count (VCC) microbiological assay has been utilized for over a decade to measure the antimicrobial activity of peptides such as defensins and LL-37 against biosafety level (BSL)-1 and BSL-2 bacteria including Escherichia coli, Staphylococcus aureus, Bacillus cereus, and Enterobacter aerogenes.  In addition, a modified pipetting technique was presented in a 2011 study of defensin activity against the BSL-3 pathogen Bacillus anthracis.  Both studies were published in the journal Antimicrobial Agents and Chemotherapy.  Here I report that the method can also detect cross-contamination caused by aerosols utilizing the VCC method of data analysis by quantitative growth kinetics (QGK).  The QGK threshold time, or T t, equivalent to the cycle time C t reported in 1996 by Heid et al., precisely identifies when wells were inoculated. PMID:25671086

  9. Determination of the antimicrobial properties of oligo-2-hydroxy-1-naphthaldehyde.

    PubMed

    Yapici, Binnur Meriçli; Kaya, Ismet; Senol, Dilek

    2005-01-01

    Oligo-2-hydroxy-1-naphthaldehyde (OHNA) was synthesized by oxidative polycondensation using H2O2 (35%, aqueous solution), air O2 and NaOCl (34%, aqueous solution) by Kaya and Senol and the products were characterized by spectral techniques. Antimicrobial activities of the first and second fractions of OHNA were tested against Corynobacterium xerosis CCM 2824, Proteus vulgaris ATCC 6897, Staphylococcus epidermidis NRRL B-4877, S. aureus ATCC 6538, Enterobacter aerogenes ATCC 13048, Salmonella thyphimurium CCM 5445, Pseudomonas aeroginosa ATCC 27853, Escherichia coli ATCC 11230, E. coli ATCC 23998, Bacillus cereus ATCC 7064, B. cereus ATCC 99, B. subtilis ATCC 6633, Yersinia spp., Neisseria canis, Rhodotorula rubra, Kluyveromyces fragilis NRRL 2415, Saccharomyces cerevisiae ATCC 9763, S. ovarum, Debaryomyces hensenii, Hansenula anamola, Candida albicans, C. utilis, Aspergillus niger, A. fumigates, A. versicolor, A. flavus, A. parasiticus, Penicillium granulatum, P. chrysogenum, and P. herque. OHNA demonstrated antimicrobial activity against various bacteria and yeast, but did not affect filamentous fungi. PMID:16355978

  10. Osteoconductive composite graft based on bacterial synthesized hydroxyapatite nanoparticles doped with different ions: From synthesis to in vivo studies.

    PubMed

    Ahmadzadeh, Elham; Talebnia, Farid; Tabatabaei, Meisam; Ahmadzadeh, Hossein; Mostaghaci, Babak

    2016-07-01

    To repair damaged bone tissues, osteoconductive bone graft substitutes are required for enhancement of the regenerative potential of osteoblast cells. Nanostructured hydroxyapatite is a bioactive ceramic used for bone tissue engineering purposes. In this study, carbonate hydroxyapatite (cHA) and zinc-magnesium substituted hydroxyapatite (Zn-Mg-HA) nanoparticles were synthesized via biomineralization method using Enterobacter aerogenes. The structural phase composition and the morphology of the samples were analyzed using appropriate powder characterization methods. Next, a composite graft was fabricated by using polyvinyl alcohol and both cHA and Zn-Mg-HA samples. In vivo osteogenic potential of the graft was then investigated in a rabbit tibial osteotomy model. Histological, radiological and morphological studies showed that the graft was mineralized by the newly formed bone tissue without signs of inflammation or infection after 4 weeks of implantation. These histomorphometric results suggest that the fabricated graft can function as a potent osteoconductive bone tissue substitute. PMID:26956413

  11. Control of infection with multiple antibiotic resistant bacteria in a hospital renal unit: the value of plasmid characterization.

    PubMed Central

    Reed, C. S.; Barrett, S. P.; Threlfall, E. J.; Cheasty, T.

    1995-01-01

    An outbreak of infections due to multiple antibiotic-resistant bacteria took place over a period of approximately 18 months in a renal unit. Strains of Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Citrobacter spp. and Pseudomonas spp. were involved, and a variety of antibiotic resistances was encountered. Closely related plasmids encoding resistance to aztreonam, ceftazidime and piperacillin, possibly derived from an archetypal plasmid of 105 kb were found in the majority of isolates examined. After limiting the use of aztreonam the incidence of new patient isolates of multiple-resistant organisms was greatly reduced. This study demonstrated how molecular studies can contribute to the control of an outbreak situation in a hospital unit by providing an impetus to reduce the use of specific antibiotics. Images Fig. 2 PMID:7641839

  12. Antimicrobial activity of honokiol and magnolol isolated from Magnolia officinalis.

    PubMed

    Ho, K Y; Tsai, C C; Chen, C P; Huang, J S; Lin, C C

    2001-03-01

    The antimicrobial activity of honokiol and magnolol, the main constituents of Magnolia officinalis was investigated. The antimicrobial activity was assayed by the agar dilution method using brain heart infusion medium and the minimum inhibitory concentration (MIC) were determined for each compound using a twofold serial dilution assay. The results showed that honokiol and magnolol have a marked antimicrobial effect (MIC = 25 microg/mL) against Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Micrococcus luteus and Bacillus subtilis, but did not show antimicrobial activity (MIC > or = 100 microg/mL) for Shigella flexneii, Staphylococcus epidermidis, Enterobacter aerogenes, Proteus vulgaris, Escherichia coli and Pseudomonas aeruginosa. Our results indicate that honokiol and magnolol, although less potent than tetracycline, show a significant antimicrobial activity for periodontal pathogens. Hence we suggest that honokiol and magnolol might have the potential to be an adjunct in the treatment of periodontitis. PMID:11268114

  13. Potential for detection of microorganisms and heavy metals in potable water using electronic nose technology.

    PubMed

    Canhoto, Olinda F; Magan, Naresh

    2003-05-01

    Studies have been carried out to determine the potential for the detection of different microbial species (Enterobacter aerogenes, Escherichia coli, Pseudomonas aeruginosa), alone and in the presence of low concentrations of different heavy metals (As, Cd, Pb and Zn) in bottled, reverse osmosis (RO) and tap water, using an electronic nose. Studies show that it is possible to discriminate control water samples from water contaminated with 0.5 ppm of a mixture of metals. The presence of heavy metals may modify the activity of microorganisms and thus the volatile production patterns. Bacterial species at 10(2)-10(4) colony forming units (CFUs) ml(-1) could be detected after 24 h of incubation. Work is in progress to identify the limits of detection for a range of other microorganisms, including, fungi and cyanobacteria, and chlorinated phenols using electronic nose technology. PMID:12706588

  14. [Sensibility of rabbits to treatment with ampicillin and gentamycin (author's transl)].

    PubMed

    Escoula, L; Camguilhem, R; Larrieu, G; More, J

    1981-01-01

    Ampicillin administered to rabbits (20 mg/kg per day) over a period of three days subsequently provoked a death rate of 40%. No deaths were observed after treatment with gentamycin (10 mg/kg per day) or with a combination of ampicillin and gentamycin. On the fourth day weight loss in the three treated groups was 12%, 11% and 9%, respectively, compared to controls. At the same time food intake in the treated groups was only 15% to 20% of the amount consumed by controls. In the caecum, ampicillin treatment resulted in dominance of a strain of Enterobacter aerogenes. Gentamycin had no effect on bacterial flora, although in combination with ampicillin, the number of caecal bacteria (aerobic and anaerobic) was reduced. Flora modification might be responsible for accumulation of NH3 and an unbalance of free acids. Caecotrophy was inhibited by administration of ampicillin. When administered intramuscularly, ampicillin produced results comparable with those obtained orally, although gentamycin was ineffective. PMID:7342822

  15. Chromosomal Integration and Expression of Two Bacterial α-Acetolactate Decarboxylase Genes in Brewer's Yeast

    PubMed Central

    Blomqvist, K.; Suihko, M.-L.; Knowles, J.; Penttilä, M.

    1991-01-01

    A bacterial gene encoding α-acetolactate decarboxylase, isolated from Klebsiella terrigena or Enterobacter aerogenes, was expressed in brewer's yeast. The genes were expressed under either the yeast phosphoglycerokinase (PGK1) or the alcohol dehydrogenase (ADH1) promoter and were integrated by gene replacement by using cotransformation into the PGK1 or ADH1 locus, respectively, of a brewer's yeast. The expression level of the α-acetolactate decarboxylase gene of the PGK1 integrant strains was higher than that of the ADH1 integrants. Under pilot-scale brewing conditions, the α-acetolactate decarboxylase activity of the PGK1 integrant strains was sufficient to reduce the formation of diacetyl below the taste threshold value, and no lagering was needed. The brewing properties of the recombinant yeast strains were otherwise unaltered, and the quality (most importantly, the flavor) of the trial beers produced was as good as that of the control beer. Images PMID:16348559

  16. Biological properties of the Chilean native moss Sphagnum magellanicum.

    PubMed

    Montenegro, Gloria; Portaluppi, Mariana C; Salas, Francisco A; Díaz, María F

    2009-01-01

    An ethanol extract prepared from the gametophyte Chilean native moss Sphagnum magellanicum was dried out, weighed and dissolved in distilled water. This extract was then assayed for its antibacterial activity against the G(-) bacteria Azotobacter vinelandii, Erwinia carotovora subsp. carotovora, Enterobacter aerogenes, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Vibrio cholerae, and the G(+) bacteria Staphylococcus aureus subsp. aureus, and Streptococcus type beta. The growth of the cultures of E. carotovora subsp. carotovora, and V. cholerae was inhibited at a concentration of 581 microg/ml of extract, while the cultures of E. coli, S. typhi and Streptococcus type beta were inhibited at a concentration of 1.16 microg/mL of extract. The concentration of phenolic compounds was 4.294 mg/mL; the presence of vanillic, chlorogenic, syringic, caffeic, gallic, 3-4 hydrozybenzoic, p-coumaric and salicylic acids was identified using RP- High Pressure Liquid Chromatography. PMID:19746269

  17. Decoction, infusion and hydroalcoholic extract of cultivated thyme: antioxidant and antibacterial activities, and phenolic characterisation.

    PubMed

    Martins, Natália; Barros, Lillian; Santos-Buelga, Celestino; Silva, Sónia; Henriques, Mariana; Ferreira, Isabel C F R

    2015-01-15

    Bioactivity of thyme has been described, but mostly related to its essential oils, while studies with aqueous extracts are scarce. Herein, the antioxidant and antibacterial properties of decoction, infusion and hydroalcoholic extract, as also their phenolic compounds, were evaluated and compared. Decoction showed the highest concentration of phenolic compounds (either phenolic acids or flavonoids), followed by infusion and hydroalcoholic extract. In general, the samples were effective against gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and gram-negative (Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Enterococcus aerogenes, Proteus vulgaris and Enterobacter sakazakii) bacteria, with decoction presenting the most pronounced effect. This sample also displayed the highest radical scavenging activity and reducing power. Data obtained support the idea that compounds with strong antioxidant and antibacterial activities are also water-soluble. Furthermore, the use of thyme infusion and decoction, by both internal and external use, at recommended doses, is safe and no adverse reactions have been described. PMID:25148969

  18. Efflux Pump Blockers in Gram-Negative Bacteria: The New Generation of Hydantoin Based-Modulators to Improve Antibiotic Activity

    PubMed Central

    Otręebska-Machaj, Ewa; Chevalier, Jacqueline; Handzlik, Jadwiga; Szymańska, Ewa; Schabikowski, Jakub; Boyer, Gérard; Bolla, Jean-Michel; Kieć-Kononowicz, Katarzyna; Pagès, Jean-Marie; Alibert, Sandrine

    2016-01-01

    Multidrug resistant (MDR) bacteria are an increasing health problem with the shortage of new active antibiotic agents. Among effective mechanisms that contribute to the spread of MDR Gram-negative bacteria are drug efflux pumps that expel clinically important antibiotic classes out of the cell. Drug pumps are attractive targets to restore the susceptibility toward the expelled antibiotics by impairing their efflux activity. Arylhydantoin derivatives were investigated for their potentiation of activities of selected antibiotics described as efflux substrates in Enterobacter aerogenes expressing or not AcrAB pump. Several compounds increased the bacterial susceptibility toward nalidixic acid, chloramphenicol and sparfloxacin and were further pharmacomodulated to obtain a better activity against the AcrAB producing bacteria. PMID:27199950

  19. Insights into the global regulation of anaerobic metabolism for improved biohydrogen production.

    PubMed

    Lu, Yuan; Zhao, Hongxin; Zhang, Chong; Xing, Xin-Hui

    2016-01-01

    To improve the biohydrogen yield in bacterial dark fermentation, a new approach of global anaerobic regulation was introduced. Two cellular global regulators FNR and NarP were overexpressed in two model organisms: facultatively anaerobic Enterobacter aerogenes (Ea) and strictly anaerobic Clostridium paraputrificum (Cp). The overexpression of FNR and NarP greatly altered anaerobic metabolism and increased the hydrogen yield by 40%. Metabolic analysis showed that the global regulation caused more reducing environment inside the cell. To get a thorough understanding of the global metabolic regulation, more genes (fdhF, fhlA, ppk, Cb-fdh1, and Sc-fdh1) were overexpressed in different Ea and Cp mutants. For the first time, it demonstrated that there were approximately linear relationships between the relative change of hydrogen yield and the relative change of NADH yield or ATP yield. It implied that cellular reducing power and energy level played vital roles in the biohydrogen production. PMID:26476162

  20. Community-onset Gram-negative Surveillance Program annual report, 2012.

    PubMed

    Turnidge, John D; Gottlieb, Thomas; Mitchell, David H; Coombs, Geoffrey W; Daly, Denise A; Bell, Jan M

    2014-03-01

    The Australian Group on Antimicrobial Resistance performs regular period-prevalence studies to monitor changes in antimicrobial resistance in selected enteric Gram-negative pathogens. The 2012 survey focussed on community-onset infections, examining isolates from urinary tract infections from patients presenting to outpatient clinics, emergency departments or to community practitioners. In 2012, 2,025 Escherichia coli, 538 Klebsiella species and 239 Enterobacter species were tested using a commercial automated method (Vitek 2, BioMérieux) and results were analysed using Clinical and Laboratory Standards Institute breakpoints from January 2012. Of the key resistances, non-susceptibility to the third-generation cephalosporin, ceftriaxone, was found in 4.2% of E. coli and 4.6%-6.9% of Klebsiella spp. Non-susceptibility rates to ciprofloxacin were 6.9% for E. coli, 0.0%-3.5% for Klebsiella spp. and 0.8%-1.9% in Enterobacter spp, and resistance rates to piperacillin-tazobactam were 1.7%, 0.7%-9.2%, and 8.8%-11.4% for the same 3 groups respectively. Only 1 Enterobacter cloacae was shown to harbour a carbapenemase (IMP-4). PMID:25409356

  1. Biochemical characteristics and identification of Enterobacteriaceae isolated from meats.

    PubMed

    Stiles, M E; Ng, L K

    1981-03-01

    The isolation and identification of 2,220 Enterobacteriaceae from meats indicated that Escherichia coli biotype I, Enterobacter agglomerans, and Serratia liquefaciens were the principal types to be differentiated in meats. Citrobacter freundii, Klebsiella pneumoniae, Enterobacter cloacae, and Enterobacter hafniae were also commonly identified. Identification of isolates by the Encise II (Roche Diagnostics Inc., Nutley, N.J.) and Minitek (BBL Microbiology Systems, Cockeysville, Md.) coding systems gave similar results with only 255 (11.5%) discrepancies in identity, but both systems required large numbers of supplementary tests for identification of the isolates. Not only the distribution of Enterobacteriaceae types isolated from meats but also some of the biochemical reactions of the isolates differed from those of clinical isolates. The Minitek technique is recommended because of its versatility. However, with the addition of cellobiose and salicin disks and the inclusion of methyl red to the Minitek test and the use of the Voges-Proskauer test and gas production in EC medium at elevated temperature as standard tests, the identification of these Enterobacteriaceae from meats would be greatly facilitated. The inclusion of the motility test, for example, using nitrate motility agar, would also be of value to Enterobacteriaceae identification. PMID:7013705

  2. Sulphonate utilization by enteric bacteria.

    PubMed

    Uria-Nickelsen, M R; Leadbetter, E R; Godchaux, W

    1993-02-01

    A variety of sulphonates were tested for their ability to serve as nutrients for Escherichia coli, Enterobacter aerogenes and Serratia marcescens. Cysteate, taurine and isethionate could not serve as sole sources of carbon and energy but, under aerobic conditions, could be utilized as sources of sulphur. Both sulphate and sulphonate supported equivalent cell yields, but the generation times varied with the sulphonate being metabolized. The sulphonate-S of HEPES buffer, dodecane sulphonate and methane sulphonate was also utilized by some strains, whereas the sulphonate-S of taurocholate was not. None of the sulphonates tested served as a sulphur source for growth under anaerobic conditions. Sulphonate utilization appears to be a constitutive trait; surprisingly, however, cells of E. coli and Ent. aerogenes utilized sulphate-S in preference to that of sulphonate, when both were present. E. coli mutants unable to use sulphate as a source of sulphur because of deficiencies in sulphate permease, ATP sulphurylase, adenylylsulphate kinase (APS kinase) or glutaredoxin and thioredoxin were able to utilize sulphonates; hence sulphate is not an obligatory intermediate in sulphonate utilization. However, mutants deficient in sulphite reductase were unable to utilize sulphonates; therefore, this enzyme must be involved in sulphonate utilization, though it is not yet known whether it acts upon the sulphonates themselves or upon the inorganic sulphite derived from them. PMID:8436944

  3. Prevalence of multidrug resistant uropathogenic bacteria in pediatric patients of a tertiary care hospital in eastern India.

    PubMed

    Mishra, Monali P; Sarangi, Rachita; Padhy, Rabindra N

    2016-01-01

    Today, because systemic infections such as urinary tract infection (UTI) affect even pediatric patients, antibiotic resistant bacteria have become a constant clinical challenge. In the present study, a total of 1054 urine samples were collected from pediatric patients over 18 months. From these samples, 510 isolates of pathogenic bacteria were collected using HiCrome UTI agar. Antibiotic sensitivity tests of isolates were performed using the Kirby-Bauer method. Two Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus) and 7 Gram-negative bacteria (Citrobacter freundii, Enterobacter aerogenes, Escherichia coli, Klebsiella oxytoca, K. pneumoniae, Proteus vulgaris and Pseudomonas aeruginosa) were isolated. Antibiograms of isolated bacteria were ascertained using antibiotics of 4 classes: aminoglycosides, β-lactams, fluoroquinolones and 2 stand-alones (co-trimoxazole and nitrofurantoin). Based on percent values of antibiotic resistance, isolated bacteria were (in decreasing order of number of isolated isolates): E. coli (109)>S. aureus (65)>E. faecalis (82)>E. aerogenes (64)>C. freundii (41)>P. aeruginosa (32)>K. pneumoniae (45)>K. oxytoca (50)>P. vulgaris (22). Surveillance results show that MDR isolates of 9 pathogenic bacteria were prevalent in the environment around the hospital. Thus, revisions to the antimicrobial stewardship program in this area of the country are required to increase clinician confidence in empiric therapy, which is often used for UTI cases. PMID:26617250

  4. In Vitro Antibacterial Efficacy of 21 Indian Timber-Yielding Plants Against Multidrug-Resistant Bacteria Causing Urinary Tract Infection

    PubMed Central

    Mishra, Monali P.; Padhy, Rabindra N.

    2013-01-01

    Objectives To screen methanolic leaf extracts of 21 timber-yielding plants for antibacterial activity against nine species of uropathogenic bacteria isolated from clinical samples of a hospital (Enterococcus faecalis, Staphylococcus aureus, Acinetobacter baumannii, Citrobacter freundii, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa). Methods Bacterial strains were subjected to antibiotic sensitivity tests by the Kirby–Bauer's disc diffusion method. The antibacterial potentiality of leaf extracts was monitored by the agar-well diffusion method with multidrug-resistant (MDR) strains of nine uropathogens. Results Two Gram-positive isolates, E. faecalis and S. aureus, were resistant to 14 of the 18 antibiotics used. Gram-negative isolates A. baumannii, C. freundii, E. aerogenes, E. coli, K. pneumoniae, P. mirabilis, and P. aeruginosa were resistant to 10, 12, 9, 11, 11, 10, and 11 antibiotics, respectively, of the 14 antibiotics used. Methanolic leaf extracts of Anogeissus acuminata had the maximum zone of inhibition size—29 mm against S. aureus and 28 mm against E. faecalis and P. aeruginosa. Cassia tora had 29 mm as the zone of inhibition size for E. faecalis, E. aerogenes, and P. aeruginosa. Based on the minimum inhibitory concentration and minimum bactericidal concentration values, the most effective 10 plants against uropathogens could be arranged in decreasing order as follows: C. tora > A. acuminata > Schleichera oleosa > Pterocarpus santalinus > Eugenia jambolana > Bridelia retusa > Mimusops elengi > Stereospermum kunthianum > Tectona grandis > Anthocephalus cadamba. The following eight plants had moderate control capacity: Artocarpus heterophyllus, Azadirachta indica, Dalbergia latifolia, Eucalyptus citriodora, Gmelina arborea, Pongamia pinnata, Pterocarpus marsupium, and Shorea robusta. E. coli, followed by A. baumannii, C. freundii, E. aerogenes, P. mirabilis, and P

  5. Identification and characterization of a phospholipase A2 from the venom of the Saw-scaled viper: Novel bactericidal and membrane damaging activities.

    PubMed

    Perumal Samy, Ramar; Gopalakrishnakone, P; Bow, Ho; Puspharaj, Peter N; Chow, Vincent T K

    2010-12-01

    Phospholipase A(2) (PLA(2)), a common toxic component of snake venom, has been implicated in various pharmacological effects. In this study, a basic myotoxic PLA(2), named EcTx-I was isolated from Echis carinatus snake venom by using gel filtration on Superdex G-75, and reverse phase HPLC on C18 and C8 Sepharose columns. PLA(2), EcTx-I was 13,861.72 molecular weight as estimated by MALDI-TOF (15 kD by SDS-PAGE), and consisted of 121 amino acid residues cross-linked by seven disulfide bonds. The N-terminal sequences revealed significant homology with basic myotoxic PLA(2)s from other snake venoms. The purified PLA(2) EcTx-I was evaluated (250 μg/ml) for bactericidal activity of a wide variety of human pathogens against Burkholderia pseudomallei (KHW&TES), Enterobacter aerogenes, Escherichia coli, Proteus vulgaris, Proteus mirabilis, Pseudomonas aeruginosa and Staphylococcus aureus. EcTx-I showed strong antibacterial activity against B. pseudomallei (KHW) and E. aerogenes among the tested bacteria. Other Gram-negative and Gram-positive bacteria showed only a moderate effect. However, the Gram-positive bacterium E. aerogenes failed to show any effect on EcTx-I protein at tested doses. The most significant bacteriostatic and bactericidal effect of EcTx-I was observed at MICs of >15 μg/ml against (B. pseudomallei, KHW) and MICs >30 μg/ml against E. aerogenes. Mechanisms of bactericidal and membrane damaging effects were proved by ultra-structural analysis. EcTx-I was able to induce cytotoxicity on THP-1 cells in vitro as well as lethality in BALB/c mice. EcTx-I also induced mild myotoxic effects on mouse skin, but was devoid of hemolytic effects on human erythrocytes up to 500 μg/ml. It is shown that the toxic effect induced by E. carinatus venom is due to the presence of myotoxic PLA(2) (EcTx-I). The result also corroborates the hypothesis of an association between toxic and enzymatic domains. In conclusion, EcTx-I displays a heparin binding C-terminal region

  6. Dissemination of Cronobacter spp. (Enterobacter sakazakii) in a Powdered Milk Protein Manufacturing Facility▿

    PubMed Central

    Mullane, N.; Healy, B.; Meade, J.; Whyte, P.; Wall, P. G.; Fanning, S.

    2008-01-01

    The microbial contamination of air filters and possible links to contaminated product in a powdered milk protein-processing facility were investigated. Over a 10-month period, seven air filters, the environment, and powdered product were analyzed for the presence of Cronobacter spp. The effects of air filter installation, maintenance, and subsequent dissemination of Cronobacter were investigated. A total of 30 isolates were characterized by pulsed-field gel electrophoresis (PFGE). PFGE revealed the presence of three clonal populations distributed throughout the manufacturing site. This study highlights the need for proper installation of air filters to limit the dissemination of microorganisms into processing sites. PMID:18641152

  7. Identification of Natural Antimicrobial Substances in Red Muscadine Juice against Enterobacter sakazakii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red muscadine (Vitis rotundifolia Michx.) juices with natural organic, phenolic acids and polyphenol compounds were tested against Cronobacter sakazakii. The concentration of total phenolic compounds of commercial baby juices ranged from 176.7 to 347.7 mg/mL. Commercial baby juices showed poor antim...

  8. Artificial citrate operon and Vitreoscilla hemoglobin gene enhanced mineral phosphate solubilizing ability of Enterobacter hormaechei DHRSS.

    PubMed

    Yadav, Kavita; Kumar, Chanchal; Archana, G; Kumar, G Naresh

    2014-10-01

    Mineral phosphate solubilization by bacteria is mediated through secretion of organic acids, among which citrate is one of the most effective. To overproduce citrate in bacterial systems, an artificial citrate operon comprising of genes encoding NADH-insensitive citrate synthase of E. coli and Salmonella typhimurium sodium-dependent citrate transporter was constructed. In order to improve its mineral phosphate solubilizing (MPS) ability, the citrate operon was incorporated into E. hormaechei DHRSS. The artificial citrate operon transformant secreted 7.2 mM citric acid whereas in the native strain, it was undetectable. The transformant released 0.82 mM phosphate in flask studies in buffered medium containing rock phosphate as sole P source. In fermenter studies, similar phenotype was observed under aerobic conditions. However, under microaerobic conditions, no citrate was detected and P release was not observed. Therefore, an artificial citrate gene cluster containing Vitreoscilla hemoglobin (vgb) gene under its native promoter, along with artificial citrate operon under constitutive tac promoter, was constructed and transformed into E. hormaechei DHRSS. This transformant secreted 9 mM citric acid under microaerobic conditions and released 1.0 mM P. Thus, incorporation of citrate operon along with vgb gene improves MPS ability of E. hormaechei DHRSS under buffered, microaerobic conditions mimicking rhizospheric environment. PMID:25016342

  9. Pyrosequencing analysis of microbial community and food-borne bacteria on restaurant cutting boards collected in Seri Kembangan, Malaysia, and their correlation with grades of food premises.

    PubMed

    Abdul-Mutalib, Noor-Azira; Amin Nordin, Syafinaz; Osman, Malina; Ishida, Natsumi; Tashiro, Kosuke; Sakai, Kenji; Tashiro, Yukihiro; Maeda, Toshinari; Shirai, Yoshihito

    2015-05-01

    This study adopts the pyrosequencing technique to identify bacteria present on 26 kitchen cutting boards collected from different grades of food premises around Seri Kembangan, a city in Malaysia. Pyrosequencing generated 452,401 of total reads of OTUs with an average of 1.4×10(7) bacterial cells/cm(2). Proteobacteria, Firmicutes and Bacteroides were identified as the most abundant phyla in the samples. Taxonomic richness was generally high with >1000 operational taxonomic units (OTUs) observed across all samples. The highest appearance frequencies (100%) were OTUs closely related to Enterobacter sp., Enterobacter aerogenes, Pseudomonas sp. and Pseudomonas putida. Several OTUs were identified most closely related to known food-borne pathogens, including Bacillus cereus, Cronobacter sakazaki, Cronobacter turisensis, Escherichia coli, E. coli O157:H7, Hafnia alvei, Kurthia gibsonii, Salmonella bongori, Salmonella enterica, Salmonella paratyphi, Salmonella tyhpi, Salmonella typhimurium and Yersinia enterocolitica ranging from 0.005% to 0.68% relative abundance. The condition and grade of the food premises on a three point cleanliness scale did not correlate with the bacterial abundance and type. Regardless of the status and grades, all food premises have the same likelihood to introduce food-borne bacteria from cutting boards to their foods and must always prioritize the correct food handling procedure in order to avoid unwanted outbreak of food-borne illnesses. PMID:25679309

  10. Efficacy of plant essential oils against foodborne pathogens and spoilage bacteria associated with ready-to-eat vegetables: antimicrobial and sensory screening.

    PubMed

    Gutierrez, Jorge; Rodriguez, Gabriel; Barry-Ryan, Catherine; Bourke, Paula

    2008-09-01

    The objectives of this study were to evaluate the antimicrobial activity of plant essential oils (EOs) against foodborne pathogens and key spoilage bacteria pertinent to ready-to-eat vegetables and to screen the selected EOs for sensory acceptability. The EOs basil, caraway, fennel, lemon balm, marjoram, nutmeg, oregano, parsley, rosemary, sage, and thyme were evaluated. The bacteria evaluated were Listeria spp., Staphylococcus aureus, Lactobacillus spp., Bacillus cereus, Salmonella, Enterobacter spp., Escherichia coli, and Pseudomonas spp. Quantitative antimicrobial analyses were performed using an absorbance-based microplate assay. Efficacy was compared using MIC, the half maximum inhibitory concentration, and the increase in lag phase. Generally, gram-positive bacteria were more sensitive to EOs than were gram-negative bacteria, and Listeria monocytogenes strains were among the most sensitive. Of the spoilage organisms, Pseudomonas spp. were the most resistant. Oregano and thyme EOs had the highest activity against all the tested bacteria. Marjoram and basil EOs had selectively high activity against B. cereus, Enterobacter aerogenes, E. coli, and Salmonella, and lemon balm and sage EOs had adequate activity against L. monocytogenes and S. aureus. Within bacterial species, EO efficacy was dependent on strain and in some cases the origin of the strain. On a carrot model product, basil, lemon balm, marjoram, oregano, and thyme EOs were deemed organoleptically acceptable, but only oregano and marjoram EOs were deemed acceptable for lettuce. Selected EOs may be useful as natural and safe additives for promoting the safety and quality of ready-to-eat vegetables. PMID:18810868

  11. Carbapenem-Nonsusceptible Enterobacteriaceae in Taiwan

    PubMed Central

    Wang, Jann-Tay; Wu, Un-In; Lauderdale, Tsai-Ling Yang; Chen, Mei-Chen; Li, Shu-Ying; Hsu, Le-Yin; Chang, Shan-Chwen

    2015-01-01

    A total of 1135 carbapenem-resistant (nonsusceptible) Enterobacteriaceae (CRE) isolates were recovered between November 2010 and July 2012 (517 from 2010-2011 and 618 from 2012) from 4 hospitals in Taiwan. Carbapenemase-producing Enterobacteriaceae (CPE) comprised 5.0% (57 isolates), including 17 KPC-2 (16 Klebsiella pneumoniae and 1 Escherichia coli), 1 NDM-1 (K. oxytoca), 37 IMP-8 (26 Enterobacter cloacae, 4 Citrobacter freundii, 4 Raoultella planticola, 1 K. pneumoniae, 1 E. coli and 1 K. oxytoca), and 2 VIM-1 (1 E. cloacae, 1 E. coli). The KPC-2-positive K. pneumoniae were highly clonal even in isolates from different hospitals, and all were ST11. IMP-8 positive E. cloacae from the same hospitals showed higher similarity in PFGE pattern than those from different hospitals. A total of 518 CRE isolates (45.6%) were positive for blaESBL, while 704 (62.0%) isolates were blaAmpC-positive, 382 (33.6% overall) of which carried both blaESBL and blaAmpC. CTX-M (414, 80.0%) was the most common blaESBL, while DHA (497, 70.6%) and CMY (157, 22.3%) were the most common blaAmpC. Co-carriage of blaESBL and blaAmpC was detected in 31 (54.4%) and 15 (26.3%) of the 57 CPE, respectively. KPC-2 was the most common carbapenemase detected in K. pneumoniae (2.8%), while IMP-8 was the most common in E. cloacae (9.7%). All KPC-2-positive CRE were resistant to all three tested carbapenems. However, fourteen of the 37 IMP-8-positive CRE were susceptible to both imipenem and meropenem in vitro. Intra- and inter-hospital spread of KPC-2-producing K. pneumoniae and IMP-8-producing E. cloacae likely occurred. Although the prevalence of CPE is still low, careful monitoring is urgently needed. Non-susceptibility to ertapenem might need to be considered as one criterion of definition for CRE in areas where IMP type carbapenemase is prevalent. PMID:25794144

  12. Cockroaches as carriers of bacteria in multi-family dwellings.

    PubMed Central

    Cloarec, A.; Rivault, C.; Fontaine, F.; Le Guyader, A.

    1992-01-01

    The potential risk of bacterial dissemination due to the presence of cockroaches (Blattella germanica, Blattellidae) in low-income flats was investigated. Cockroaches can carry a great variety of bacterial species; we identified 30 different species from 52 different flats. Klebsiella oxycytoca, K. pneumoniae and Enterobacter cloacae were the most frequently found. Pathogenic and potentially pathogenic bacteria represented 54% of all the bacterial identifications. Bacteria were carried either on the cuticle or in the gut. Contamination through external contact is sufficient to insure bacterial diffusion. There was a very low level of overlap estimated by Pianka's index (a) between the bacterial flora of neighbouring blocks of flats, and (b) between bacterial flora of different flats in the same block. PMID:1468532

  13. Effects of genetically engineered microorganisms on nitrogen transformations and nitrogen-transforming microbial populations in soil

    SciTech Connect

    Jones, R.A.; Broder, M.W.; Stotzky, G. )

    1991-11-01

    The principal concern about releasing genetically engineered microorganisms (GEMs) into the environment is their potential adverse effects on the environment, whether caused directly or indirectly by the GEMs. The effects of five GEMs on ammonification, nitrification, and denitrification in soil were studied. With the possible exception of a strain of Enterobacter cloacae carrying a plasmid, no consistent statistically or ecologically significant differences in effects on these processes or on the population dynamics of the microorganisms responsible for the processes were observed between soils inoculated with GEMs or their homologous plasmidless hosts and those that were not inoculated. Increasing the concentration of montmorillonite in the soil enhanced the rate of nitrification, regardless of the inoculum, indicating that the perfusion technique used was sensitive enough to detect changes in nitrification rates when they occurred.

  14. Discrimination of selected species of pathogenic bacteria using near-infrared Raman spectroscopy and principal components analysis

    NASA Astrophysics Data System (ADS)

    de Siqueira e Oliveira, Fernanda SantAna; Giana, Hector Enrique; Silveira, Landulfo

    2012-10-01

    A method, based on Raman spectroscopy, for identification of different microorganisms involved in bacterial urinary tract infections has been proposed. Spectra were collected from different bacterial colonies (Gram-negative: Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Enterobacter cloacae, and Gram-positive: Staphylococcus aureus and Enterococcus spp.), grown on culture medium (agar), using a Raman spectrometer with a fiber Raman probe (830 nm). Colonies were scraped from the agar surface and placed on an aluminum foil for Raman measurements. After preprocessing, spectra were submitted to a principal component analysis and Mahalanobis distance (PCA/MD) discrimination algorithm. We found that the mean Raman spectra of different bacterial species show similar bands, and S. aureus was well characterized by strong bands related to carotenoids. PCA/MD could discriminate Gram-positive bacteria with sensitivity and specificity of 100% and Gram-negative bacteria with sensitivity ranging from 58 to 88% and specificity ranging from 87% to 99%.

  15. Improvement of biogas production by bioaugmentation.

    PubMed

    Kovács, K L; Ács, N; Kovács, E; Wirth, R; Rákhely, G; Strang, Orsolya; Herbel, Zsófia; Bagi, Z

    2013-01-01

    Biogas production technologies commonly involve the use of natural anaerobic consortia of microbes. The objective of this study was to elucidate the importance of hydrogen in this complex microbial food chain. Novel laboratory biogas reactor prototypes were designed and constructed. The fates of pure hydrogen-producing cultures of Caldicellulosiruptor saccharolyticus and Enterobacter cloacae were followed in time in thermophilic and mesophilic natural biogas-producing communities, respectively. Molecular biological techniques were applied to study the altered ecosystems. A systematic study in 5-litre CSTR digesters revealed that a key fermentation parameter in the maintenance of an altered population balance is the loading rate of total organic solids. Intensification of the biogas production was observed and the results corroborate that the enhanced biogas productivity is associated with the increased abundance of the hydrogen producers. Fermentation parameters did not indicate signs of failure in the biogas production process. Rational construction of more efficient and sustainable biogas-producing microbial consortia is proposed. PMID:23484123

  16. Determination of mercury and organomercurial resistance in obligate anaerobic bacteria.

    PubMed

    Rudrik, J T; Bawdon, R E; Guss, S P

    1985-03-01

    A methodology for determining the minimum inhibitory concentration of inorganic and organomercurial compounds for obligate anaerobic bacteria is described. A wide variation in the susceptibility of anaerobic clinical and sewage isolates was observed. Isolates of Bacteroides ruminicola and Clostridium perfringens resistant to mercury were examined for their plasmid content and ability to demonstrate inducible resistance. None of the resistant anaerobes contained any plasmids, while resistant facultative isolates from the same source contained several plasmids. In 24 h, resistant strains of clostridia and Bacteroides volatilized 20 and 43% of the 203Hg2+ added to cultures, while Escherichia coli R100 and a sewage isolate of Enterobacter cloacae volatilized 63 and 27%, respectively, of the added 203Hg2+. Attempts to induce mercury resistance in the aerobic isolates were successful, but no induction was seen in the anaerobes. Thus, mercury resistance in these anaerobic isolates was neither inducible nor plasmid mediated. PMID:4005712

  17. Lactic acid bacteria convert glucosinolates to nitriles efficiently yet differently from enterobacteriaceae.

    PubMed

    Mullaney, Jane A; Kelly, William J; McGhie, Tony K; Ansell, Juliet; Heyes, Julian A

    2013-03-27

    Glucosinolates from the genus Brassica can be converted into bioactive compounds known to induce phase II enzymes, which may decrease the risk of cancers. Conversion via hydrolysis is usually by the brassica enzyme myrosinase, which can be inactivated by cooking or storage. We examined the potential of three beneficial bacteria, Lactobacillus plantarum KW30, Lactococcus lactis subsp. lactis KF147, and Escherichia coli Nissle 1917, and known myrosinase-producer Enterobacter cloacae to catalyze the conversion of glucosinolates in broccoli extract. Enterobacteriaceae consumed on average 65% glucoiberin and 78% glucoraphanin, transforming them into glucoiberverin and glucoerucin, respectively, and small amounts of iberverin nitrile and erucin nitrile. The lactic acid bacteria did not accumulate reduced glucosinolates, consuming all at 30-33% and transforming these into iberverin nitrile, erucin nitrile, sulforaphane nitrile, and further unidentified metabolites. Adding beneficial bacteria to a glucosinolate-rich diet may increase glucosinolate transformation, thereby increasing host exposure to bioactives. PMID:23461529

  18. Differentiation of whole bacterial cells based on high-throughput microarray chip printing and infrared microspectroscopic readout.

    PubMed

    Al-Khaldi, Sufian F; Mossoba, Magdi M; Burke, Tara L; Fry, Frederick S

    2009-10-01

    Using robotic automation, a microarray printing protocol for whole bacterial cells was developed for subsequent label-free and nondestructive infrared microspectroscopic detection. Using this contact microspotting system, 24 microorganisms were printed on zinc selenide slides; these were 6 species of Listeria, 10 species of Vibrio, 2 strains of Photobacterium damselae, Yersinia enterocolitica 289, Bacillus cereus ATCC 14529, Staphylococcus aureus, ATCC 19075 (serotype 104 B), Shigella sonnei 20143, Klebsiella pneumoniae KP73, Enterobacter cloacae, Citrobacter freundii 200, and Escherichia coli. Microarrays consisting of separate spots of bacterial deposits gave consistent and reproducible infrared spectra, which were differentiated by unsupervised pattern recognition algorithms. Two multivariate analysis algorithms, principal component analysis and hierarchical cluster analysis, successfully separated most, but not all, the bacteria investigated down to the species level. PMID:19630511

  19. Cloning, sequencing, and use as a molecular probe of a gene encoding an aminoglycoside 6'-N-acetyltransferase of broad substrate profile.

    PubMed Central

    Terán, F J; Suárez, J E; Mendoza, M C

    1991-01-01

    A gene coding for an aminoglycoside 6'-N-acetyltransferase that was able to modify amikacin was cloned from a plasmid isolated from a clinical strain of Enterobacter cloacae. Sequencing of a 955-bp segment which mediates the modifying activity revealed a single open reading frame of 432 nucleotides that predicted a polypeptide of 144 amino acid residues with a molecular weight of 16,021. Putative ribosomal binding sites and -10 and -35 sequences were located at the 5' end of the gene. The size of the polypeptide was confirmed through minicell analysis of the expression products of plasmids containing the sequence. The use of the gene as a molecular probe revealed its specificity toward strains harboring genes coding for related enzymes. This probe is therefore useful for epidemiological studies. Images PMID:2069376

  20. Antibacterial effects of the essential oils of commonly consumed medicinal herbs using an in vitro model.

    PubMed

    Soković, Marina; Glamočlija, Jasmina; Marin, Petar D; Brkić, Dejan; van Griensven, Leo J L D

    2010-11-01

    The chemical composition and antibacterial activity of essential oils from 10 commonly consumed herbs: Citrus aurantium, C. limon, Lavandula angustifolia, Matricaria chamomilla, Mentha piperita, M. spicata, Ocimum basilicum, Origanum vulgare, Thymus vulgaris and Salvia officinalis have been determined. The antibacterial activity of these oils and their main components; i.e. camphor, carvacrol, 1,8-cineole, linalool, linalyl acetate, limonene, menthol, a-pinene, b-pinene, and thymol were assayed against the human pathogenic bacteria Bacillus subtilis, Enterobacter cloacae, Escherichia coli O157:H7, Micrococcus flavus, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella enteritidis, S. epidermidis, S. typhimurium, and Staphylococcus aureus. The highest and broadest activity was shown by O. vulgare oil. Carvacrol had the highest antibacterial activity among the tested components. PMID:21030907