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Sample records for acinetobacter strains including

  1. Genome organization of epidemic Acinetobacter baumannii strains

    PubMed Central

    2011-01-01

    Background Acinetobacter baumannii is an opportunistic pathogen responsible for hospital-acquired infections. A. baumannii epidemics described world-wide were caused by few genotypic clusters of strains. The occurrence of epidemics caused by multi-drug resistant strains assigned to novel genotypes have been reported over the last few years. Results In the present study, we compared whole genome sequences of three A. baumannii strains assigned to genotypes ST2, ST25 and ST78, representative of the most frequent genotypes responsible for epidemics in several Mediterranean hospitals, and four complete genome sequences of A. baumannii strains assigned to genotypes ST1, ST2 and ST77. Comparative genome analysis showed extensive synteny and identified 3068 coding regions which are conserved, at the same chromosomal position, in all A. baumannii genomes. Genome alignments also identified 63 DNA regions, ranging in size from 4 o 126 kb, all defined as genomic islands, which were present in some genomes, but were either missing or replaced by non-homologous DNA sequences in others. Some islands are involved in resistance to drugs and metals, others carry genes encoding surface proteins or enzymes involved in specific metabolic pathways, and others correspond to prophage-like elements. Accessory DNA regions encode 12 to 19% of the potential gene products of the analyzed strains. The analysis of a collection of epidemic A. baumannii strains showed that some islands were restricted to specific genotypes. Conclusion The definition of the genome components of A. baumannii provides a scaffold to rapidly evaluate the genomic organization of novel clinical A. baumannii isolates. Changes in island profiling will be useful in genomic epidemiology of A. baumannii population. PMID:21985032

  2. Diverse responses to UV light exposure in Acinetobacter include the capacity for DNA damage-induced mutagenesis in the opportunistic pathogens Acinetobacter baumannii and Acinetobacter ursingii.

    PubMed

    Hare, Janelle M; Bradley, James A; Lin, Ching-li; Elam, Tyler J

    2012-03-01

    Error-prone and error-free DNA damage repair responses that are induced in most bacteria after exposure to various chemicals, antibiotics or radiation sources were surveyed across the genus Acinetobacter. The error-prone SOS mutagenesis response occurs when DNA damage induces a cell's umuDC- or dinP-encoded error-prone polymerases. The model strain Acinetobacter baylyi ADP1 possesses an unusual, regulatory umuD allele (umuDAb) with an extended 5' region and only incomplete fragments of umuC. Diverse Acinetobacter species were investigated for the presence of umuDC and their ability to conduct UV-induced mutagenesis. Unlike ADP1, most Acinetobacter strains possessed multiple umuDC loci containing either umuDAb or a umuD allele resembling that of Escherichia coli. The nearly omnipresent umuDAb allele was the ancestral umuD in Acinetobacter, with horizontal gene transfer accounting for over half of the umuDC operons. Despite multiple umuD(Ab)C operons in many strains, only three species conducted UV-induced mutagenesis: Acinetobacter baumannii, Acinetobacter ursingii and Acinetobacter beijerinckii. The type of umuDC locus or mutagenesis phenotype a strain possessed was not correlated with its error-free response of survival after UV exposure, but similar diversity was apparent. The survival of 30 Acinetobacter strains after UV treatment ranged over five orders of magnitude, with the Acinetobacter calcoaceticus-A. baumannii (Acb) complex and haemolytic strains having lower survival than non-Acb or non-haemolytic strains. These observations demonstrate that a genus can possess a range of DNA damage response mechanisms, and suggest that DNA damage-induced mutation could be an important part of the evolution of the emerging pathogens A. baumannii and A. ursingii.

  3. Diverse responses to UV light exposure in Acinetobacter include the capacity for DNA damage-induced mutagenesis in the opportunistic pathogens Acinetobacter baumannii and Acinetobacter ursingii

    PubMed Central

    Bradley, James A.; Lin, Ching-li; Elam, Tyler J.

    2012-01-01

    Error-prone and error-free DNA damage repair responses that are induced in most bacteria after exposure to various chemicals, antibiotics or radiation sources were surveyed across the genus Acinetobacter. The error-prone SOS mutagenesis response occurs when DNA damage induces a cell’s umuDC- or dinP-encoded error-prone polymerases. The model strain Acinetobacter baylyi ADP1 possesses an unusual, regulatory umuD allele (umuDAb) with an extended 5′ region and only incomplete fragments of umuC. Diverse Acinetobacter species were investigated for the presence of umuDC and their ability to conduct UV-induced mutagenesis. Unlike ADP1, most Acinetobacter strains possessed multiple umuDC loci containing either umuDAb or a umuD allele resembling that of Escherichia coli. The nearly omnipresent umuDAb allele was the ancestral umuD in Acinetobacter, with horizontal gene transfer accounting for over half of the umuDC operons. Despite multiple umuD(Ab)C operons in many strains, only three species conducted UV-induced mutagenesis: Acinetobacter baumannii, Acinetobacter ursingii and Acinetobacter beijerinckii. The type of umuDC locus or mutagenesis phenotype a strain possessed was not correlated with its error-free response of survival after UV exposure, but similar diversity was apparent. The survival of 30 Acinetobacter strains after UV treatment ranged over five orders of magnitude, with the Acinetobacter calcoaceticus–A. baumannii (Acb) complex and haemolytic strains having lower survival than non-Acb or non-haemolytic strains. These observations demonstrate that a genus can possess a range of DNA damage response mechanisms, and suggest that DNA damage-induced mutation could be an important part of the evolution of the emerging pathogens A. baumannii and A. ursingii. PMID:22117008

  4. Phenotypic and physiological changes in Acinetobacter sp. strain DR1 with exogenous plasmid.

    PubMed

    Park, Jungsoon; Park, Woojun

    2011-01-01

    The genus Acinetobacter has been recognized to take up exogenous DNA from the environment. In this study, we conducted natural transformation with a novel diesel-degrading Acinetobacter sp. strain, designated strain DR1, using the broad host range plasmid pRK415. Many factors, including temperature, quantities of DNA, and aeration have proven critically important for efficient natural transformation. Interestingly, the Acinetobacter sp. strain DR1 (pRK415) differed both phenotypically and physiologically from the wild-type strain in several regards, including motility, biofilm formation ability, and responses to oxidative stress: the transformed cells were rendered more sensitive to hydrogen peroxide and cumene hydroperoxide, and their motilities and biofilm formation activity were also attenuated. Our data demonstrated that caution should be exercised when conducting genetic manipulation with plasmids, due to the possibility that phenotypic and physiological changes in the host might occur along with the uptake of plasmids.

  5. Polymicrobial Chronic Infection Including Acinetobacter Baumannii in a Plated Segmental Defect in the Rat Femur

    DTIC Science & Technology

    2008-01-01

    Including Acinetobacter baumannii in a Plated Segmental Defect in the Rat Femur PRINCIPAL INVESTIGATOR: Dean T. Tsukayama, MD...FEB 2007 - 31 DEC 2007 4. TITLE AND SUBTITLE Polymicrobial Chronic Infection Including Acinetobacter baumannii 5a. CONTRACT NUMBER in a Plated...bone isolate of Acinetobacter baumannii exhibited very little osteolytic involvement when used alone in the model. Qualitative cultures indicated very

  6. Draft Genome Sequences of Multidrug-Resistant Acinetobacter sp. Strains from Colombian Hospitals

    PubMed Central

    Falquet, Laurent; Reguero, María T.; Mantilla, José R.; Valenzuela, Emilia M.; González, Elsa; Cepeda, Alexandra; Escalante, Andrea

    2013-01-01

    The draft genome sequences of the strains Acinetobacter baumannii 107m, Acinetobacter nosocomialis 28F, and Acinetobacter pittii 42F, isolated from Colombian hospitals, are reported here. These isolates are causative of nosocomial infections and are classified as multidrug resistant, as they showed resistance to four different antibiotic groups. PMID:24285656

  7. The activity of silver nanoparticles (Axonnite) on clinical and environmental strains of Acinetobacter spp.

    PubMed

    Łysakowska, Monika E; Ciebiada-Adamiec, Anna; Klimek, Leszek; Sienkiewicz, Monika

    2015-03-01

    Acinetobacter baumannii isolates are responsible for a high number of wound infections. The reason of this study was to evaluate the activity of silver nanoparticles obtained by microexplosion against wide range of Acinetobacter spp. Susceptibility to silver nanoparticles was tested by microdilution method, susceptibility to antibiotics was evaluated by the disc-diffusion method. All strains of Acinetobacter spp. were sensitive to AgNPs at low concentrations. The values of the MIC for strains of Acinetobacter spp. were 0.39 and 0.78μg/mL. In general, strains inhibited by 0.78μg/mL of AgNPs were more resistant to antibiotics than Acinetobacter strains for which MIC=0.39μg/mL (p=0.023). The AgNPs in Axonnite seems to be a good alternative for other antimicrobials to treat wound infections caused by multidrug resistant Acinetobacter spp. strains because of its high activity.

  8. Draft Genome Sequence of JVAP01T, the Type Strain of the Novel Species Acinetobacter dijkshoorniae

    PubMed Central

    Fernández-Orth, Dietmar; Cosgaya, Clara; Telli, Murat; Mosqueda, Noraida; Marí-Almirall, Marta

    2017-01-01

    ABSTRACT Here, we report the draft genome sequence of the type strain of Acinetobacter dijkshoorniae, a novel human pathogen within the Acinetobacter calcoaceticus–Acinetobacter baumannii (ACB) complex. Strain JVAP01T has an estimated genome size of 3.9 Mb, exhibits a 38.8% G+C content, and carries a plasmid with the blaNDM-1 carbapenemase gene. PMID:28082506

  9. Genome Sequence of an Acinetobacter baumannii Strain Carrying Three Acquired Carbapenemase Genes

    PubMed Central

    Oinuma, Ken-Ichi; Suzuki, Masato; Sato, Kanako; Nakaie, Kiyotaka; Niki, Makoto; Takizawa, Etsuko; Niki, Mamiko; Shibayama, Keigo; Yamada, Koichi; Kakeya, Hiroshi

    2016-01-01

    The emergence of multiple-carbapenemase-producing Acinetobacter strains has been a serious concern during the past decade. Here, we report the draft genome sequence of an Acinetobacter baumannii strain isolated from a Japanese patient with three acquired carbapenemase genes: blaNDM-1, blaTMB-1, and blaOXA-58. PMID:27856588

  10. Draft Genome Sequence of the Environmentally Isolated Acinetobacter pittii Strain IPK_TSA6.1

    PubMed Central

    Lee, Yunmi

    2016-01-01

    Acinetobacter pittii is an opportunistic pathogen frequently isolated from Acinetobacter infections other than those from Acinetobacter baumannii. Multidrug resistance in A. pittii, including resistance to carbapenems, has been increasingly reported worldwide. Here, we report the 4.14-Mbp draft genome sequence of A. pittii IPK_TSA6.1 that was isolated from a nonhospital setting. PMID:27688336

  11. Comparison of the Virulence Potential of Acinetobacter Strains from Clinical and Environmental Sources

    PubMed Central

    Tayabali, Azam F.; Nguyen, Kathy C.; Shwed, Philip S.; Crosthwait, Jennifer; Coleman, Gordon; Seligy, Verner L.

    2012-01-01

    Several Acinetobacter strains have utility for biotechnology applications, yet some are opportunistic pathogens. We compared strains of seven Acinetobacter species (baumannii, Ab; calcoaceticus, Ac; guillouiae, Ag; haemolyticus, Ah; lwoffii, Al; junii, Aj; and venetianus, Av-RAG-1) for their potential virulence attributes, including proliferation in mammalian cell conditions, haemolytic/cytolytic activity, ability to elicit inflammatory signals, and antibiotic susceptibility. Only Ah grew at 102 and 104 bacteria/well in mammalian cell culture medium at 37°C. However, co-culture with colonic epithelial cells (HT29) improved growth of all bacterial strains, except Av-RAG-1. Cytotoxicity of Ab and Ah toward HT29 was at least double that of other test bacteria. These effects included bacterial adherence, loss of metabolism, substrate detachment, and cytolysis. Only Ab and Ah exhibited resistance to killing by macrophage-like J774A.1 cells. Haemolytic activity of Ah and Av-RAG-1 was strong, but undetectable for other strains. When killed with an antibiotic, Ab, Ah, Aj and Av-RAG-1 induced 3 to 9-fold elevated HT29 interleukin (IL)-8 levels. However, none of the strains altered levels of J774A.1 pro-inflammatory cytokines (IL-1β, IL-6 and tumor necrosis factor-α). Antibiotic susceptibility profiling showed that Ab, Ag and Aj were viable at low concentrations of some antibiotics. All strains were positive for virulence factor genes ompA and epsA, and negative for mutations in gyrA and parC genes that convey fluoroquinolone resistance. The data demonstrate that Av-RAG-1, Ag and Al lack some potentially harmful characteristics compared to other Acinetobacter strains tested, but the biotechnology candidate Av-RAG-1 should be scrutinized further prior to widespread use. PMID:22655033

  12. Complete Genome Sequence of an Acinetobacter Strain Harboring the NDM-1 Gene.

    PubMed

    Sun, Yang; Song, Yang; Song, Hongbin; Liu, Jun; Wang, Pengzhi; Qiu, Shaofu; Chen, Shuo; Zhu, Lingwei; Ji, Xue; Wang, Zhongqiang; Liu, Nan; Xia, Liliang; Chen, Weijun; Feng, Shuzhang

    2013-04-18

    The NDM-1 gene is a significant public health concern. Acinetobacter is one of the most prevalent opportunistic pathogens causing recent nosocomial infections with NDM-1, and drug-resistant strains pose serious threats to public health worldwide. Herein, we present the genomic sequence of Acinetobacter calcoaceticus subsp. anitratus XM1570, a multidrug-resistant isolate that carries the blaNDM-1 gene.

  13. Complete Genome Sequence of Acinetobacter sp. Strain NCu2D-2 Isolated from a Mouse

    PubMed Central

    Blaschke, Ulrike

    2017-01-01

    ABSTRACT Whole-genome sequencing of Acinetobacter sp. strain NCu2D-2, isolated from the trachea of a mouse, revealed the presence of a plasmid of 309,964 bp with little overall similarity to known plasmids and enriched in insertion sequences (ISs) closely related to IS elements known from the nosocomial pathogen Acinetobacter baumannii. PMID:28126932

  14. Draft Genome Sequence of a Taxonomically Unique Acinetobacter Clinical Strain with Proteolytic and Hemolytic Activities

    PubMed Central

    Traglia, German Matías; Almuzara, Marisa; Barberis, Claudia; Montaña, Sabrina; Schramm, Sareda T. J.; Enriquez, Brandi; Mussi, María Alejandra; Vay, Carlos; Iriarte, Andres

    2015-01-01

    Acinetobacter sp. strain A47, which has been recovered from several soft tissue samples from a patient undergoing reconstructive surgery due to a traumatic amputation, was categorized as a taxonomically unique bacterial strain. The molecular analysis based on three housekeeping protein-coding genes (16S rRNA, rpoB, and gyrB) showed that strain A47 does not belong to any of the hitherto known taxa and may represent a previously undescribed Acinetobacter species. PMID:25744988

  15. Phosphoproteomics as an emerging weapon to develop new antibiotics against carbapenem resistant strain of Acinetobacter baumannii.

    PubMed

    Tiwari, Vishvanath; Tiwari, Monalisa

    2015-01-01

    Acinetobacter baumannii causes pneumonia, bloodstream infections, urinary tract infections, respiratory infections and meningitis. A. baumannii has developed resistance against most of the antibiotics including carbapenem. Therefore, to battle carbapenem resistance, there is a need to develop antimicrobial drugs with new modes of action. Phosphoproteomics will help identify the differentially phosphorylated protein and its crucial phosphosites which facilitate the elucidation of molecular mechanism of signaling and regulation of carbapenem resistant strain of A. baumannii as compared to carbapenem sensitive strain. This understanding might be useful for the development of new antibiotics against kinases involved in the phosphorylation of identified phosphosites in carbapenem resistant strain of A. baumannii. The proposed antibiotics selectively inhibit carbapenem resistant strain which further avoids its excessive use against carbapenem sensitive strain and thereafter reduces emergence of resistance.

  16. Genome Sequence of Airborne Acinetobacter sp. Strain 5-2Ac02 in the Hospital Environment, Close to the Species of Acinetobacter towneri.

    PubMed

    Barbosa, Beathriz G V; Fernandez-García, Laura; Gato, Eva; López, Maria; Blasco, Lucia; Leão, Robson Souza; Albano, Rodolpho M; Fernández, Begoña; Cuenca, Felipe-Fernández; Pascual, Álvaro; Bou, German; Marques, Elizabeth A; Tomás, María

    2016-12-08

    Acinetobacter spp. are found in 53% of air colonization samples from the hospital environment. In this work, we sequenced all the genome of airborne Acinetobacter sp. strain 5-2Ac02. We found important features at the genomic level in regards to the rhizome. By phylogenetic analysis, A. towneri was the species most closely related to Acinetobacter sp. 5-2Ac02. Copyright © 2016 Barbosa et al.

  17. Community-Acquired Bacteremic Acinetobacter Pneumonia in Tropical Australia Is Caused by Diverse Strains of Acinetobacter baumannii, with Carriage in the Throat in At-Risk Groups

    PubMed Central

    Anstey, Nicholas M.; Currie, Bart J.; Hassell, Marilyn; Palmer, Didier; Dwyer, Brian; Seifert, Harald

    2002-01-01

    Acinetobacter isolates from eight subjects with community-acquired Acinetobacter pneumonia (CAAP), a major cause of fatal community-acquired pneumonia in tropical Australia, were phenotypically and genotypically confirmed by pulsed-field gel electrophoresis analysis to be broadly diverse Acinetobacter baumannii strains. Wet-season throat carriage of A. baumannii was found in 10% of community residents with excess levels of alcohol consumption, the major at-risk group for CAAP. PMID:11825997

  18. Genome Sequence of Airborne Acinetobacter sp. Strain 5-2Ac02 in the Hospital Environment, Close to the Species of Acinetobacter towneri

    PubMed Central

    Barbosa, Beathriz G. V.; Fernandez-García, Laura; Gato, Eva; López, Maria; Blasco, Lucia; Leão, Robson Souza; Albano, Rodolpho M.; Fernández, Begoña; Cuenca, Felipe-Fernández; Pascual, Álvaro; Bou, German; Marques, Elizabeth A.

    2016-01-01

    Acinetobacter spp. are found in 53% of air colonization samples from the hospital environment. In this work, we sequenced all the genome of airborne Acinetobacter sp. strain 5-2Ac02. We found important features at the genomic level in regards to the rhizome. By phylogenetic analysis, A. towneri was the species most closely related to Acinetobacter sp. 5-2Ac02. PMID:27932646

  19. Distribution of AdeABC efflux system genes in genotypically diverse strains of clinical Acinetobacter baumannii.

    PubMed

    Wieczorek, Piotr; Sacha, Paweł; Czaban, Sławomir; Hauschild, Tomasz; Ojdana, Dominika; Kowalczuk, Oksana; Milewski, Robert; Poniatowski, Bogusław; Nikliński, Jacek; Tryniszewska, Elżbieta

    2013-10-01

    Acinetobacter baumannii has emerged as a highly problematic hospital-associated pathogen. Different mechanisms contribute to the formation of multidrug resistance in A. baumannii, including the AdeABC efflux system. Distribution of the structural and regulatory genes encoding the AdeABC efflux system among genetically diverse clinical A. baumannii strains was achieved by using PCR and pulsed-field gel electrophoresis techniques. The distribution of adeABRS genes is extremely high among our A. baumannii strains, except the adeC gene. We have observed a large proportion of strains presenting multidrug-resistance phenotype for several years. The efflux pump could be an important mechanism in these strains in resistance to antibiotics.

  20. Taxonomy of haemolytic and/or proteolytic strains of the genus Acinetobacter with the proposal of Acinetobacter courvalinii sp. nov. (genomic species 14 sensu Bouvet & Jeanjean), Acinetobacter dispersus sp. nov. (genomic species 17), Acinetobacter modestus sp. nov., Acinetobacter proteolyticus sp. nov. and Acinetobacter vivianii sp. nov.

    PubMed

    Nemec, Alexandr; Radolfova-Krizova, Lenka; Maixnerova, Martina; Vrestiakova, Eliska; Jezek, Petr; Sedo, Ondrej

    2016-04-01

    We aimed to define the taxonomic status of 40 haemolytic and/or proteolytic strains of the genus Acinetobacter which were previously classified into five putative species termed as genomic species 14BJ (n=9), genomic species 17 (n=9), taxon 18 (n=7), taxon 19 (n=6) and taxon 20 (n=9). The strains were recovered mostly from human clinical specimens or soil and water ecosystems and were highly diverse in geographical origin and time of isolation. Comparative analysis of the rpoB and gyrB gene sequences of all strains, and the whole-genome sequences of selected strains, showed that these putative species formed five respective, well-supported clusters within a distinct clade of the genus Acinetobacter which typically, although not exclusively, encompasses strains with strong haemolytic activity. The whole-genome-based average nucleotide identity (ANIb) values supported the species status of each of these clusters. Moreover, the distinctness and coherence of the clusters were supported by whole-cell profiling based on MALDI-TOF MS. Congruent with these findings were the results of metabolic and physiological testing. We conclude that the five putative taxa represent respective novel species, for which the names Acinetobacter courvalinii sp. nov. (type strain ANC 3623T=CCUG 67960T=CIP 110480T=CCM 8635T), Acinetobacter dispersus sp. nov. (type strain ANC 4105T=CCUG 67961T=CIP 110500T=CCM 8636T), Acinetobacter modestus sp. nov. (type strain NIPH 236T=CCUG 67964T=CIP 110444T=CCM 8639T), Acinetobacter proteolyticus sp. nov. (type strain NIPH 809T=CCUG 67965T=CIP 110482T = CCM 8640T) and Acinetobacter vivianii sp. nov. (type strain NIPH 2168T=CCUG 67967T=CIP 110483T=CCM 8642T) are proposed.

  1. Characterization and identification of newly isolated Acinetobacter baumannii strain serdang 1 for phenol removal

    NASA Astrophysics Data System (ADS)

    Yadzir, Z. H. M.; Shukor, M. Y.; Nazir, M. S.; Abdullah, M. A.

    2012-09-01

    A new indigenous bacterial strain from Malaysian soil contaminated with petroleum waste had been successfully isolated, characterized and identified for phenol removal. The gram negative bacteria showed 98% identity with Acinetobacter baumannii based on Biolog{trade mark, serif} Identification System and the determination of a partial 16S ribosomal RNA (rRNA) sequence. The isolate clustered with species belonging to Acinetobacter clade in a 16S rDNA-based neighbour-joining phylogenetic tree.

  2. Draft Genome Sequence of a Multidrug-Resistant Acinetobacter baumannii Strain from Chile

    PubMed Central

    Lopes, Bruno S.; García, Patricia; Domínguez Yévenes, Mariana; Lima, Celia; Bello-Toledo, Helia; González-Rocha, Gerardo; Amyes, Sebastian G. B.

    2015-01-01

    Acinetobacter baumannii strain Ab5 was isolated in the year 2007 in Chile, being one of the first multidrug-resistant (MDR) cases reported in the country. Here, we present the very first draft genome sequence of an MDR Chilean strain, which shows the presence of diverse resistance and acquired virulence genes. PMID:26139713

  3. Draft Genome Sequence of a Multidrug-Resistant Acinetobacter baumannii Strain from Chile.

    PubMed

    Opazo, Andrés; Lopes, Bruno S; García, Patricia; Domínguez Yévenes, Mariana; Lima, Celia; Bello-Toledo, Helia; González-Rocha, Gerardo; Amyes, Sebastian G B

    2015-07-02

    Acinetobacter baumannii strain Ab5 was isolated in the year 2007 in Chile, being one of the first multidrug-resistant (MDR) cases reported in the country. Here, we present the very first draft genome sequence of an MDR Chilean strain, which shows the presence of diverse resistance and acquired virulence genes. Copyright © 2015 Opazo et al.

  4. Characterization of plasmids in extensively drug-resistant acinetobacter strains isolated in India and Pakistan.

    PubMed

    Jones, Lim S; Carvalho, Maria J; Toleman, Mark A; White, P Lewis; Connor, Thomas R; Mushtaq, Ammara; Weeks, Janis L; Kumarasamy, Karthikeyan K; Raven, Katherine E; Török, M Estée; Peacock, Sharon J; Howe, Robin A; Walsh, Timothy R

    2015-02-01

    The blaNDM-1 gene is associated with extensive drug resistance in Gram-negative bacteria. This probably spread to Enterobacteriaceae from Acinetobacter spp., and we characterized plasmids associated with blaNDM-1 in Acinetobacter spp. to gain insight into their role in this dissemination. Four clinical NDM-1-producing Acinetobacter species strains from India and Pakistan were investigated. A plasmid harboring blaNDM-1, pNDM-40-1, was characterized by whole-genome sequencing of Acinetobacter bereziniae CHI-40-1 and comparison with related plasmids. The presence of similar plasmids in strains from Pakistan was sought by PCR and sequencing of amplicons. Conjugation frequency was tested and stability of pNDM-40-1 investigated by real-time PCR of isolates passaged with and without antimicrobial selection pressure. A. bereziniae and Acinetobacter haemolyticus strains contained plasmids similar to the pNDM-BJ01-like plasmids identified in Acinetobacter spp. in China. The backbone of pNDM-40-1 was almost identical to that of pNDM-BJ01-like plasmids, but the transposon harboring blaNDM-1, Tn125, contained two short deletions. Escherichia coli and Acinetobacter pittii transconjugants were readily obtained. Transconjugants retained pNDM-40-1 after a 14-day passage experiment, although stability was greater with meropenem selection. Fragments of pNDM-BJ01-like plasmid backbones are found near blaNDM-1 in some genetic contexts from Enterobacteriaceae, suggesting that cross-genus transfer has occurred. pNDM-BJ01-like plasmids have been described in isolates originating from a wide geographical region in southern Asia. In vitro data on plasmid transfer and stability suggest that these plasmids could have contributed to the spread of blaNDM-1 into Enterobacteriaceae.

  5. Characterization of Plasmids in Extensively Drug-Resistant Acinetobacter Strains Isolated in India and Pakistan

    PubMed Central

    Carvalho, Maria J.; Toleman, Mark A.; White, P. Lewis; Connor, Thomas R.; Mushtaq, Ammara; Weeks, Janis L.; Kumarasamy, Karthikeyan K.; Raven, Katherine E.; Török, M. Estée; Peacock, Sharon J.; Howe, Robin A.; Walsh, Timothy R.

    2014-01-01

    The blaNDM-1 gene is associated with extensive drug resistance in Gram-negative bacteria. This probably spread to Enterobacteriaceae from Acinetobacter spp., and we characterized plasmids associated with blaNDM-1 in Acinetobacter spp. to gain insight into their role in this dissemination. Four clinical NDM-1-producing Acinetobacter species strains from India and Pakistan were investigated. A plasmid harboring blaNDM-1, pNDM-40-1, was characterized by whole-genome sequencing of Acinetobacter bereziniae CHI-40-1 and comparison with related plasmids. The presence of similar plasmids in strains from Pakistan was sought by PCR and sequencing of amplicons. Conjugation frequency was tested and stability of pNDM-40-1 investigated by real-time PCR of isolates passaged with and without antimicrobial selection pressure. A. bereziniae and Acinetobacter haemolyticus strains contained plasmids similar to the pNDM-BJ01-like plasmids identified in Acinetobacter spp. in China. The backbone of pNDM-40-1 was almost identical to that of pNDM-BJ01-like plasmids, but the transposon harboring blaNDM-1, Tn125, contained two short deletions. Escherichia coli and Acinetobacter pittii transconjugants were readily obtained. Transconjugants retained pNDM-40-1 after a 14-day passage experiment, although stability was greater with meropenem selection. Fragments of pNDM-BJ01-like plasmid backbones are found near blaNDM-1 in some genetic contexts from Enterobacteriaceae, suggesting that cross-genus transfer has occurred. pNDM-BJ01-like plasmids have been described in isolates originating from a wide geographical region in southern Asia. In vitro data on plasmid transfer and stability suggest that these plasmids could have contributed to the spread of blaNDM-1 into Enterobacteriaceae. PMID:25421466

  6. Unique Structural Modifications Are Present in the Lipopolysaccharide from Colistin-Resistant Strains of Acinetobacter baumannii

    PubMed Central

    Pelletier, Mark R.; Casella, Leila G.; Jones, Jace W.; Adams, Mark D.; Zurawski, Daniel V.; Hazlett, Karsten R. O.; Doi, Yohei

    2013-01-01

    Acinetobacter baumannii is a nosocomial opportunistic pathogen that can cause severe infections, including hospital-acquired pneumonia, wound infections, and sepsis. Multidrug-resistant (MDR) strains are prevalent, further complicating patient treatment. Due to the increase in MDR strains, the cationic antimicrobial peptide colistin has been used to treat A. baumannii infections. Colistin-resistant strains of A. baumannii with alterations to the lipid A component of lipopolysaccharide (LPS) have been reported; specifically, the lipid A structure was shown to be hepta-acylated with a phosphoethanolamine (pEtN) modification present on one of the terminal phosphate residues. Using a tandem mass spectrometry platform, we provide definitive evidence that the lipid A isolated from colistin-resistant A. baumannii MAC204 LPS contains a novel structure corresponding to a diphosphoryl hepta-acylated lipid A structure with both pEtN and galactosamine (GalN) modifications. To correlate our structural studies with clinically relevant samples, we characterized colistin-susceptible and -resistant isolates obtained from patients. These results demonstrated that the clinical colistin-resistant isolate had the same pEtN and GalN modifications as those seen in the laboratory-adapted A. baumannii strain MAC204. In summary, this work has shown complete structure characterization including the accurate assignment of acylation, phosphorylation, and glycosylation of lipid A from A. baumannii, which are important for resistance to colistin. PMID:23877686

  7. Gene Structures and Regulation of the Alkane Hydroxylase Complex in Acinetobacter sp. Strain M-1

    PubMed Central

    Tani, Akio; Ishige, Takeru; Sakai, Yasuyoshi; Kato, Nobuo

    2001-01-01

    In the long-chain n-alkane degrader Acinetobacter sp. strain M-1, two alkane hydroxylase complexes are switched by controlling the expression of two n-alkane hydroxylase-encoding genes in response to the chain length of n-alkanes, while rubredoxin and rubredoxin ruductase are encoded by a single gene and expressed constitutively. PMID:11160120

  8. Draft Genome Sequence of the Biofilm-Hyperproducing Acinetobacter baumannii Clinical Strain MAR002

    PubMed Central

    Álvarez-Fraga, Laura; López, María; Merino, María; Rumbo-Feal, Soraya; Tomás, María

    2015-01-01

    We report the draft genome sequence of Acinetobacter baumannii strain MAR002, a biofilm-hyperproducing clinical strain isolated during the study CP/09/0033 (GEIH/REIPI-Ab2010, Spain). The genome of A. baumannii MAR002 has an approximate length of 3,717,929 bp and 3,300 protein-coding sequences, with a C+G content of 39.09%. PMID:26205868

  9. Draft Genome Sequence of an Extensively Drug-Resistant Acinetobacter baumannii Indigo-Pigmented Strain

    PubMed Central

    Traglia, German; Vilacoba, Elisabet; Almuzara, Marisa; Diana, Leticia; Iriarte, Andres; Centrón, Daniela

    2014-01-01

    Last year in 2013, we reported an outbreak due to indigo-pigmented Acinetobacter baumannii strains in a hospital from Buenos Aires, Argentina. Here, we present the draft genome sequence of one of the strains (A. baumannii A33405) involved in the outbreak. This isolate was categorized as extensively drug-resistant (XDR) and harbors different genetic elements associated with horizontal genetic transfer and multiple antibiotic resistances. PMID:25395633

  10. Draft Genome Sequence of an International Clonal Lineage 1 Acinetobacter baumannii Strain from Argentina

    PubMed Central

    Vilacoba, Elisabet; Déraspe, Maxime; Traglia, German M.; Roy, Paul H.; Centrón, Daniela

    2014-01-01

    In the last few years Acinetobacter baumannii has emerged worldwide as an important nosocomial pathogen in medical institutions. Here, we present the draft genome sequence of the international clonal lineage 1 (ICL1) A. baumannii strain A144 that was isolated in a hospital in Buenos Aires City in the year 1997. The strain is susceptible to carbapenems and resistant to trimethoprim and gentamicin. PMID:25428965

  11. Spread of Amikacin Resistance in Acinetobacter baumannii Strains Isolated in Spain Due to an Epidemic Strain

    PubMed Central

    Vila, Jordi; Ruiz, Joaquim; Navia, Margarita; Becerril, Berta; Garcia, Isabel; Perea, Sofia; Lopez-Hernandez, Inmaculada; Alamo, Isabel; Ballester, Frederic; Planes, Anna M.; Martinez-Beltran, Jesus; De Anta, Teresa Jimenez

    1999-01-01

    Sixteen amikacin-resistant clinical Acinetobacter baumannii isolates from nine different hospitals in Spain were investigated to determine whether the high incidence of amikacin-resistant A. baumannii was due to the dissemination of an amikacin-resistant strain or to the spread of an amikacin resistance gene. The epidemiological relationship studied by repetitive extragenic palindromic PCR and low-frequency restriction analysis of chromosomal DNA showed that the same clone was isolated in eight of nine hospitals, although other clones were also found. The strains were studied for the presence of the aph(3′)-VIa and aac(6′)-I genes, which encode enzymes which inactivate amikacin, by PCR. All 16 clinical isolates had positive PCRs with primers specific for the amplification of the aph(3′)-VIa gene, whereas none had a positive reaction for the amplification of the aac(6′)-I gene. Therefore, the high incidence of amikacin resistance among clinical A. baumannii isolates in Spain was mainly due to an epidemic strain, although the spread of the aph(3′)-VI gene cannot be ruled out. PMID:9986846

  12. Antimicrobial Activity of Gallium Protoporphyrin IX against Acinetobacter baumannii Strains Displaying Different Antibiotic Resistance Phenotypes.

    PubMed

    Arivett, Brock A; Fiester, Steven E; Ohneck, Emily J; Penwell, William F; Kaufman, Cynthia M; Relich, Ryan F; Actis, Luis A

    2015-12-01

    A paucity of effective, currently available antibiotics and a lull in antibiotic development pose significant challenges for treatment of patients with multidrug-resistant (MDR) Acinetobacter baumannii infections. Thus, novel therapeutic strategies must be evaluated to meet the demands of treatment of these often life-threatening infections. Accordingly, we examined the antibiotic activity of gallium protoporphyrin IX (Ga-PPIX) against a collection of A. baumannii strains, including nonmilitary and military strains and strains representing different clonal lineages and isolates classified as susceptible or MDR. Susceptibility testing demonstrated that Ga-PPIX inhibits the growth of all tested strains when cultured in cation-adjusted Mueller-Hinton broth, with a MIC of 20 μg/ml. This concentration significantly reduced bacterial viability, while 40 μg/ml killed all cells of the A. baumannii ATCC 19606(T) and ACICU MDR isolate after 24-h incubation. Recovery of ATCC 19606(T) and ACICU strains from infected A549 human alveolar epithelial monolayers was also decreased when the medium was supplemented with Ga-PPIX, particularly at a 40-μg/ml concentration. Similarly, the coinjection of bacteria with Ga-PPIX increased the survival of Galleria mellonella larvae infected with ATCC 19606(T) or ACICU. Ga-PPIX was cytotoxic only when monolayers or larvae were exposed to concentrations 16-fold and 1,250-fold higher than those showing antibacterial activity, respectively. These results indicate that Ga-PPIX could be a viable therapeutic option for treatment of recalcitrant A. baumannii infections regardless of the resistance phenotype, clone lineage, time and site of isolation of strains causing these infections and their iron uptake phenotypes or the iron content of the media. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  13. Antimicrobial Activity of Gallium Protoporphyrin IX against Acinetobacter baumannii Strains Displaying Different Antibiotic Resistance Phenotypes

    PubMed Central

    Arivett, Brock A.; Fiester, Steven E.; Ohneck, Emily J.; Penwell, William F.; Kaufman, Cynthia M.; Relich, Ryan F.

    2015-01-01

    A paucity of effective, currently available antibiotics and a lull in antibiotic development pose significant challenges for treatment of patients with multidrug-resistant (MDR) Acinetobacter baumannii infections. Thus, novel therapeutic strategies must be evaluated to meet the demands of treatment of these often life-threatening infections. Accordingly, we examined the antibiotic activity of gallium protoporphyrin IX (Ga-PPIX) against a collection of A. baumannii strains, including nonmilitary and military strains and strains representing different clonal lineages and isolates classified as susceptible or MDR. Susceptibility testing demonstrated that Ga-PPIX inhibits the growth of all tested strains when cultured in cation-adjusted Mueller-Hinton broth, with a MIC of 20 μg/ml. This concentration significantly reduced bacterial viability, while 40 μg/ml killed all cells of the A. baumannii ATCC 19606T and ACICU MDR isolate after 24-h incubation. Recovery of ATCC 19606T and ACICU strains from infected A549 human alveolar epithelial monolayers was also decreased when the medium was supplemented with Ga-PPIX, particularly at a 40-μg/ml concentration. Similarly, the coinjection of bacteria with Ga-PPIX increased the survival of Galleria mellonella larvae infected with ATCC 19606T or ACICU. Ga-PPIX was cytotoxic only when monolayers or larvae were exposed to concentrations 16-fold and 1,250-fold higher than those showing antibacterial activity, respectively. These results indicate that Ga-PPIX could be a viable therapeutic option for treatment of recalcitrant A. baumannii infections regardless of the resistance phenotype, clone lineage, time and site of isolation of strains causing these infections and their iron uptake phenotypes or the iron content of the media. PMID:26416873

  14. Colistin-Resistant Acinetobacter baumannii Clinical Strains with Deficient Biofilm Formation

    PubMed Central

    Dafopoulou, Konstantina; Xavier, Basil Britto; Hotterbeekx, An; Janssens, Lore; Lammens, Christine; Dé, Emmanuelle; Goossens, Herman; Tsakris, Athanasios; Malhotra-Kumar, Surbhi

    2015-01-01

    In two pairs of clinical colistin-susceptible/colistin-resistant (Csts/Cstr) Acinetobacter baumannii strains, the Cstr strains showed significantly decreased biofilm formation in static and dynamic assays (P < 0.001) and lower relative fitness (P < 0.05) compared with those of the Csts counterparts. The whole-genome sequencing comparison of strain pairs identified a mutation converting a stop codon to lysine (*241K) in LpsB (involved in lipopolysaccharide [LPS] synthesis) in one Cstr strain and a frameshift mutation in CarO and the loss of a 47,969-bp element containing multiple genes associated with biofilm production in the other. PMID:26666921

  15. Phase-Variable Control of Multiple Phenotypes in Acinetobacter baumannii Strain AB5075

    PubMed Central

    Tipton, Kyle A.; Dimitrova, Daniela

    2015-01-01

    ABSTRACT Acinetobacter baumannii strain AB5075 produces colonies with two opacity phenotypes, designated opaque and translucent. These phenotypes were unstable and opaque and translucent colony variants were observed to interconvert at high frequency, suggesting that a phase-variable mechanism was responsible. The frequency of phase variation both within colonies and in broth cultures increased in a cell density-dependent manner and was mediated by the accumulation of an extracellular factor. This factor was distinct from the known A. baumannii signaling molecule 3-OH C12-homoserine lactone. Opaque and translucent colony variants exhibited a number of phenotypic differences, including cell morphology, surface motility, biofilm formation, antibiotic resistance, and virulence in a Galleria mellonella model. Additional clinical isolates exhibited a similar phase-variable control of colony opacity, suggesting that this may be a common feature of A. baumannii. IMPORTANCE A novel phase-variable mechanism has been identified in Acinetobacter baumannii that results in an interconversion between opaque and translucent colony phenotypes. This phase variation also coordinately regulates motility, cell shape, biofilm formation, antibiotic resistance, and virulence. The frequency of phase variation is increased at high cell density via a diffusible extracellular signal. To our knowledge, this report presents the first example of phase variation in A. baumannii and also the first example of quorum sensing-mediated control of phase variation in a bacterium. The findings are important, as this phase-variable mechanism can be identified only via changes in colony opacity using oblique light; therefore, many researchers studying A. baumannii may unknowingly be working with different colony variants. PMID:26013481

  16. Complete Genome Sequence of a blaOXA-58-Producing Acinetobacter baumannii Strain Isolated from a Mexican Hospital

    PubMed Central

    Pérez-Oseguera, Ángeles; Castro-Jaimes, Semiramis; Salgado-Camargo, Abraham David; Silva-Sanchez, Jesus; Garza-González, Elvira; Castillo-Ramírez, Santiago

    2017-01-01

    ABSTRACT In this study, we present the complete genome sequence of a blaOXA-58-producing Acinetobacter baumannii strain, sampled from a Mexican hospital and not related to the international clones. PMID:28883144

  17. Complete Genome Sequence of a blaOXA-58-Producing Acinetobacter baumannii Strain Isolated from a Mexican Hospital.

    PubMed

    Pérez-Oseguera, Ángeles; Castro-Jaimes, Semiramis; Salgado-Camargo, Abraham David; Silva-Sanchez, Jesus; Garza-González, Elvira; Castillo-Ramírez, Santiago; Cevallos, Miguel Ángel

    2017-09-07

    In this study, we present the complete genome sequence of a blaOXA-58-producing Acinetobacter baumannii strain, sampled from a Mexican hospital and not related to the international clones. Copyright © 2017 Pérez-Oseguera et al.

  18. Laboratory investigation of hospital outbreak caused by two different multiresistant Acinetobacter calcoaceticus subsp. anitratus strains.

    PubMed Central

    Vila, J; Almela, M; Jimenez de Anta, M T

    1989-01-01

    During a 7-month period, from December 1986 to June 1987, multiresistant strains of Acinetobacter calcoaceticus subsp. anitratus were isolated from 25 patients in a respiratory intensive care unit. The biochemical characteristics defined two groups of strains, group 1 (14 strains) and group 2 (11 strains). Both groups had the same biochemical characteristics, but group 2 strains could assimilate adipate and phenyl acetate. Moreover, of 16 antibiotics tested only netilmicin and imipenem had some inhibitory activity for group 1 strains; group 2 strains were susceptible to mezlocillin, piperacillin, and ticarcillin. Plasmid profiles of the groups were also different. The results of a laboratory investigation (biochemical characteristics, antibiotic susceptibility, and plasmid isolation) identified two different A. calcoaceticus subsp. anitratus strains as the causes of the outbreak. Images PMID:2745682

  19. Molecular Epidemiology of Aminoglycosides Resistance in Acinetobacter Spp. with Emergence of Multidrug-Resistant Strains

    PubMed Central

    Moniri, R; Farahani, R Kheltabadi; Shajari, Gh; Shirazi, MH. Nazem; Ghasemi, A

    2010-01-01

    Background: Acinetobacter spp. is characterized as an important nosocomial pathogen and increasing antimicrobial resistance. Our aim was to evaluate antimicrobial susceptibility and aminoglycosides resistance genes of Acinetobacter spp. isolated from hospitalized patients. Methods: Sixty isolates were identified as Acinetobacter species. The isolates were tested for antibiotic resistance by disc diffusion method for 12 antimicrobials. The presence of aphA6, aacC1 aadA1, and aadB genes were detected using PCR. Results: From the isolated Acinetobacter spp. the highest resistance rate showed against amikacin, tobramycin, and ceftazidim, respectively; while isolated bacteria were more sensitive to ampicillic/subactam. More than 66% of the isolates were resistant to at least three classes of antibiotics, and 27.5% of MDR strains were resistant to all seven tested classes of antimicrobials. The higher MDR rate presented in bacteria isolated from the ICU and blood samples. More than 60% of the MDR bacteria were resistance to amikacin, ceftazidim, ciprofloxacin, piperacillin/tazobactam, doxycycline, tobramycin and levofloxacin. Also, more than 60% of the isolates contained phosphotransferase aphA6, and acetyltransferase genes aacC1, but adenylyltransferase genes aadA1 (41.7%), and aadB (3.3%) were less prominent. 21.7% of the strains contain three aminoglycoside resistance genes (aphA6, aacC1 and aadA1). Conclusion: The rising trend of resistance to aminoglycosides poses an alarming threat to treatment of such infections. The findings showed that clinical isolates of Acinetobacter spp. in our hospital carrying various kinds of aminoglycoside resistance genes. PMID:23113008

  20. Potent β-Lactam Enhancer Activity of Zidebactam and WCK 5153 against Acinetobacter baumannii, Including Carbapenemase-Producing Clinical Isolates.

    PubMed

    Moya, Bartolome; Barcelo, Isabel M; Bhagwat, Sachin; Patel, Mahesh; Bou, German; Papp-Wallace, Krisztina M; Bonomo, Robert A; Oliver, Antonio

    2017-08-28

    Multidrug-resistant Acinetobacter baumannii has rapidly spread worldwide resulting in a serious threat to hospitalized patients. Zidebactam and WCK 5153 are novel non-β-lactam bicyclo-acyl hydrazide β-lactam enhancer antibiotics being developed to target multidrug-resistant A. baumannii. The objectives of this work were to determine the penicillin-binding protein (PBP) IC50s, OXA-23 inhibition profiles, and antimicrobial activities of zidebactam and WCK 5153, alone and in combination with β-lactams, against multidrug-resistant A. baumannii MICs and time kill kinetics were performed against an A. baumannii clinical strain producing the carbapenemase OXA-23 and belonging to the widespread European clone II, sequence type 2 (ST2). Inhibition of OXA-23 purified enzyme by zidebactam, WCK 5153, and comparators was assessed. All of the compounds tested displayed Ki app values >100 μM indicating poor OXA-23 β-lactamase inhibition. The PBP IC50 values of zidebactam, WCK 5153, cefepime, ceftazidime, meropenem and sulbactam (range of concentrations tested 0.02 - 2 μg/mL) were also determined. Zidebactam and WCK 5153 demonstrated specific high-affinity PBP2 binding in A. baumannii (0.01 μg/mL for both of the compounds). MICs of zidebactam and WCK 5153 were >1024 μg/mL for wild-type and multidrug-resistant Acinetobacter spp. strains. Importantly, combinations of cefepime or sulbactam with 8 μg/mL of zidebactam or WCK 5153 led to a 4- and 8-fold MIC reduction, respectively and showed enhanced killing. Notably, several of the combinations resulted in full bacterial eradication at 24h. We conclude that zidebactam and WCK 5153 are PBP2 inhibitors that show potent β-lactam enhancer effect against A. baumannii, including a multidrug-resistant OXA-23-producing ST2 international clone. Copyright © 2017 American Society for Microbiology.

  1. Development and Evaluation of Species-Specific PCR for Detection of Nine Acinetobacter Species.

    PubMed

    Li, Xue Min; Choi, Ji Ae; Choi, In Sun; Kook, Joong Ki; Chang, Young-Hyo; Park, Geon; Jang, Sook Jin; Kang, Seong Ho; Moon, Dae Soo

    2016-05-01

    Molecular methods have the potential to improve the speed and accuracy of Acinetobacter species identification in clinical settings. The goal of this study is to develop species-specific PCR assays based on differences in the RNA polymerase beta-subunit gene (rpoB) to detect nine commonly isolated Acinetobacter species including Acinetobacter baumannii, Acinetobacter calcoaceticus, Acinetobacter pittii, Acinetobacter nosocomialis, Acinetobacter lwoffii, Acinetobacter ursingii, Acinetobacter bereziniae, Acinetobacter haemolyticus, and Acinetobacter schindleri. The sensitivity and specificity of these nine assays were measured using genomic DNA templates from 55 reference strains and from 474 Acinetobacter clinical isolates. The sensitivity of A. baumannii-specific PCR assay was 98.9%, and the sensitivity of species-specific PCR assays for all other species was 100%. The specificities of A. lwoffii- and A. schindleri-specific PCR were 97.8 and 98.9%, respectively. The specificity of species-specific PCR for all other tested Acinetobacter species was 100%. The lower limit of detection for the nine species-specific PCR assays developed in this study was 20 or 200 pg of genomic DNA from type strains of each species. The Acinetobacter species-specific PCR assay would be useful to determine the correct species among suggested candidate Acinetobacter species when conventional methods including MALDI-TOF MS identify Acinetobacter only to the genus level. The species-specific assay can be used to screen large numbers of clinical and environmental samples obtained for epidemiologic study of Acinetobacter for the presence of target species.

  2. Occurrence of an Environmental Acinetobacter baumannii Strain Similar to a Clinical Isolate in Paleosol from Croatia

    PubMed Central

    Durn, Goran; Goic-Barisic, Ivana; Kovacic, Ana

    2014-01-01

    Over the past decade, bacteria of the genus Acinetobacter have emerged as a leading cause of hospital-acquired infections. Outbreaks of Acinetobacter infections are considered to be caused exclusively by contamination and transmission in hospital environments. The natural habitats of clinically important multiresistant Acinetobacter spp. remain to be defined. In this paper, we report an incidental finding of a viable multidrug-resistant strain of Acinetobacter baumannii, related to clinical isolates, in acid paleosol from Croatia. The environmental isolate of A. baumannii showed 87% similarity to a clinical isolate originating from a hospital in this geographic area and was resistant to gentamicin, trimethoprim-sulfamethoxazole, ciprofloxacin, and levofloxacin. In paleosol, the isolate was able to survive a low pH (3.37), desiccation, and a high temperature (50°C). The probable source of A. baumannii in paleosol is illegally disposed waste of external origin situated in the abandoned quarry near the sampling site. The bacteria could have been leached from waste by storm water and thus infiltrated the paleosol. PMID:24584245

  3. Transformation of Acinetobacter sp. strain BD413 by transgenic sugar beet DNA.

    PubMed

    Gebhard, F; Smalla, K

    1998-04-01

    The ability of Acinetobacter sp. strain BD413(pFG4 delta nptII) to take up and integrate transgenic plant DNA based on homologous recombination was studied under optimized laboratory conditions. Restoration of nptII, resulting in kanamycin-resistant transformants, was observed with plasmid DNA, plant DNA, and homogenates carrying the gene nptII. Molecular analysis showed that some transformants not only restored the 317-bp deletion but also obtained additional DNA.

  4. Draft Genome Sequence of Ammonia-Producing Acinetobacter sp. Strain MCC2139 from Dairy Effluent

    PubMed Central

    Chatterjee, Debasmita; Thakur, Ashoke Ranjan

    2013-01-01

    We report the draft genome sequence of an ammonia-producing, esculin-hydrolyzing, catalase-positive, gram-negative bacterium, Acinetobacter sp. strain MCC2139. This bacterium, isolated from dairy sludge and with optimum growth at 37°C, has a genome size of 2,967,280 bp with a G+C content of 42.3%. PMID:23814111

  5. Carbapenem-resistant Acinetobacter pittii strain harboring blaOXA-72 from Brazil.

    PubMed

    Chagas, Thiago Pavoni Gomes; Tavares E Oliveira, Thamirys Rachel; D'Alincourt Carvalho-Assef, Ana Paula; Albano, Rodolpho M; Asensi, Marise Dutra

    2017-02-06

    In this study, we report the isolation of OXA-72-producing Acinetobacter pittii in Brazil. A carbapenem-resistant A. pittii strain was recovered from a hospitalized female patient from Espírito Santo, Southeastern Brazil. PCR screening and DNA sequencing allowed us to identify the presence of blaOXA-72. We observed blaOXA-72 in a ~11kb plasmid and flanked by XerC/XerD-binding sites.

  6. Isolation of a bacterial strain, Acinetobacter sp. from centrate wastewater and study of its cooperation with algae in nutrients removal.

    PubMed

    Liu, Hui; Lu, Qian; Wang, Qin; Liu, Wen; Wei, Qian; Ren, Hongyan; Ming, Caibing; Min, Min; Chen, Paul; Ruan, Roger

    2017-03-22

    Algae were able to grow healthy on bacteria-containing centrate wastewater in a pilot-scale bioreactor. The batch experiment indicated that the co-cultivation of algae and wastewater-borne bacteria improved the removal efficiencies of chemical oxygen demand and total phosphorus in centrate wastewater to 93.01% and 98.78%, respectively. A strain of beneficial aerobic bacteria, Acinetobacter sp., was isolated and its biochemical characteristics were explored. Synergistic cooperation was observed in the growth of algae and Acinetobacter sp. Removal efficiencies of some nutrients were improved significantly by the co-cultivation of algae and Acinetobacter sp. After treatment, residual nutrients in centrate wastewater reached the permissible discharge limit. The cooperation between algae and Acinetobacter sp. was in part attributed to the exchange of carbon dioxide and oxygen between the algae and bacteria. This synergetic relationship between algae and Acinetobacter sp. provided a promising way to treat the wastewater by improving the nutrients removal and biomass production.

  7. Comparative Activities of Ciprofloxacin, Clinafloxacin, Gatifloxacin, Gemifloxacin, Levofloxacin, Moxifloxacin, and Trovafloxacin against Epidemiologically Defined Acinetobacter baumannii Strains

    PubMed Central

    Heinemann, Barbara; Wisplinghoff, Hilmar; Edmond, Michael; Seifert, Harald

    2000-01-01

    In vitro activities of seven fluoroquinolones against 140 clinical Acinetobacter baumannii isolates representing 138 different strain types were determined. The rank order of activity was clinafloxacin > gatifloxacin > levofloxacin > trovafloxacin > gemifloxacin = moxifloxacin > ciprofloxacin. The 31 outbreak-related A. baumannii strains were significantly more resistant than were 109 sporadic strains. PMID:10898706

  8. Screening of Herbal-Based Bioactive Extract Against Carbapenem-Resistant Strain of Acinetobacter baumannii.

    PubMed

    Tiwari, Monalisa; Roy, Ranita; Tiwari, Vishvanath

    2016-07-01

    Acinetobacter baumannii is grouped in the ESKAPE pathogens by Infectious Disease Society of America, which is linked to high degree of morbidity, mortality, and increased costs. The high level of acquired and intrinsic resistance mechanisms of these bacteria makes it an urgent requirement to find a suitable alternative to carbapenem, a commonly prescribed drug for Acinetobacter infection. In this study, methanolic extracts of six medicinal plants were subjected to phytochemical screening and their antimicrobial activity was tested against two strains of A. baumannii (ATCC 19606, carbapenem-sensitive strain, and RS 307, carbapenem-resistant strain). Synergistic effect of the plant extracts and antibiotics was also tested. Bael or Aegle marmelos contains tannin, phenol, terpenoids, glycoside, alkaloids, coumarine, steroid, and quinones. Flowers of madar or Calotropis procera possess tannin, phenol, terpenoids, glycoside, quinone, anthraquinone, anthocyanin, coumarin, and steroid. An inhibitory growth curve was seen for both the bacterial strains when treated with A. marmelos, Curcuma longa, and leaves and flowers of C. procera. Antibiotics alone showed a small zone of inhibition, but when used with herbal extracts they exhibited larger zone of inhibition. Synergistic effect of A. marmelos and imipenem was the best against both the strains of A. baumannii. From this study, it can be concluded that extracts from A. marmelos and leaves and flowers of C. procera exhibited the most effective antibacterial activity. These herbal extracts may be used to screen the bioactive compound against the carbapenem-resistant strain of A. baumannii.

  9. A taxonomically unique Acinetobacter strain with proteolytic and hemolytic activities recovered from a patient with a soft tissue injury.

    PubMed

    Almuzara, Marisa; Traglia, German Matías; Krizova, Lenka; Barberis, Claudia; Montaña, Sabrina; Bakai, Romina; Tuduri, Alicia; Vay, Carlos; Nemec, Alexandr; Ramírez, María Soledad

    2015-01-01

    A taxonomically unique bacterial strain, Acinetobacter sp. A47, has been recovered from several soft tissue samples from a patient undergoing reconstructive surgery owing to a traumatic amputation. The results of 16S rRNA, rpoB, and gyrB gene comparative sequence analyses showed that A47 does not belong to any of the hitherto-known taxa and may represent an as-yet-unknown Acinetobacter species. The recognition of this novel organism contributes to our knowledge of the taxonomic complexity underlying infections caused by Acinetobacter.

  10. Clinical Carbapenem-Resistant Acinetobacter baylyi Strain Coharboring blaSIM-1 and blaOXA-23 from China ▿

    PubMed Central

    Zhou, Zhihui; Du, Xiaoxing; Wang, Li; Yang, Qing; Fu, Yiqi; Yu, Yunsong

    2011-01-01

    blaSIM-1 and blaOXA-23 were codetected in clinical carbapenem-resistant Acinetobacter baylyi strain NB09A30. Both of carbapenemase genes were located on a large plasmid (ca. 360 kb). blaSIM-1 was found as a gene cassette inserted into a class 1 integron identical to that determined in Acinetobacter sp. isolates from South Korea. The genetic structure of blaOXA-23 in NB09A30 was different from that in the prevalent Acinetobacter baumannii of clonal complex 92 (CC92) from the same hospital. PMID:21876057

  11. A Taxonomically Unique Acinetobacter Strain with Proteolytic and Hemolytic Activities Recovered from a Patient with a Soft Tissue Injury

    PubMed Central

    Almuzara, Marisa; Traglia, German Matías; Krizova, Lenka; Barberis, Claudia; Montaña, Sabrina; Bakai, Romina; Tuduri, Alicia; Vay, Carlos

    2014-01-01

    A taxonomically unique bacterial strain, Acinetobacter sp. A47, has been recovered from several soft tissue samples from a patient undergoing reconstructive surgery owing to a traumatic amputation. The results of 16S rRNA, rpoB, and gyrB gene comparative sequence analyses showed that A47 does not belong to any of the hitherto-known taxa and may represent an as-yet-unknown Acinetobacter species. The recognition of this novel organism contributes to our knowledge of the taxonomic complexity underlying infections caused by Acinetobacter. PMID:25392359

  12. [Evaluation of the efficacy of colistin/sulbactam combination on carbapenem-resistant Acinetobacter baumannii strains].

    PubMed

    Çetinkol, Yeliz; Telli, Murat; Altunçekiç Yıldırım, Arzu; Çalgın, Mustafa Kerem

    2016-07-01

    Acinetobacter baumannii strains, are opportunistic pathogens that cause severe nosocomial infections that are difficult to treat due to development of resistance to multiple antibiotics. As the antibiotic choices to be used in treatment are limited, combinations of a variety of antibiotics are used. The aims of this study were to identify the minimal inhibitory concentration (MIC) values of colistin and sulbactam against A.baumannii isolates and to determine the in vitro activity of colistin-sulbactam combination. A total of 50 A.baumannii strains isolated from different clinical specimens (32 tracheal aspirates, 10 blood, 6 urine and 2 wound samples) were included in the study. The identification of bacteria was performed by traditional methods and Vitek-2 (BioMerieux, France) automated system. Antibiotic susceptibilities were detected by Mueller-Hinton agar disk diffusion method and Vitek-2 automated system and the results were interpreted according to the CLSI standards. MIC values of colistin and sulbactam against A.baumannii strains and in vitro interactions of colistin-sulbactam combinations were determined with the E-test (BioMerieux, France). Fractional inhibitory concentration (FIC) index was used for the detection of efficacy of drug combinations. The presence of oxacillinase and metallo-beta-lactamase (MBL) genes that lead carbapenem resistance was investigated by polymerase chain reaction (PCR), and pulsed-field gel electrophoresis (PFGE) was performed for the determination of clonal relationship. In our study, all strains (100%) were detected as susceptible to colistin, 48 (96%) to trimethoprim/sulphamethoxazole and 18 to (36%) tigecyclin; however all of them were resistant to the other studied antibiotics, including sulbactam and carbapenem. When the colistin-sulbactam combination was assessed according to FIC index, all strains were found to have antagonistic effect. All of the carbapenem-resistant strains were positive for OXA-51 and OXA-23, and 3

  13. Resistance of Permafrost and Modern Acinetobacter lwoffii Strains to Heavy Metals and Arsenic Revealed by Genome Analysis

    PubMed Central

    Kurakov, Anton; Beletsky, Alexey; Mardanov, Andrey

    2016-01-01

    We performed whole-genome sequencing of five permafrost strains of Acinetobacter lwoffii (frozen for 15–3000 thousand years) and analyzed their resistance genes found in plasmids and chromosomes. Four strains contained multiple plasmids (8–12), which varied significantly in size (from 4,135 to 287,630 bp) and genetic structure; the fifth strain contained only two plasmids. All large plasmids and some medium-size and small plasmids contained genes encoding resistance to various heavy metals, including mercury, cobalt, zinc, cadmium, copper, chromium, and arsenic compounds. Most resistance genes found in the ancient strains of A. lwoffii had their closely related counterparts in modern clinical A. lwoffii strains that were also located on plasmids. The vast majority of the chromosomal resistance determinants did not possess complete sets of the resistance genes or contained truncated genes. Comparative analysis of various A. lwoffii and of A. baumannii strains discovered a number of differences between them: (i) chromosome sizes in A. baumannii exceeded those in A. lwoffii by about 20%; (ii) on the contrary, the number of plasmids in A. lwoffii and their total size were much higher than those in A. baumannii; (iii) heavy metal resistance genes in the environmental A. lwoffii strains surpassed those in A. baumannii strains in the number and diversity and were predominantly located on plasmids. Possible reasons for these differences are discussed. PMID:27795957

  14. Resistance of Permafrost and Modern Acinetobacter lwoffii Strains to Heavy Metals and Arsenic Revealed by Genome Analysis.

    PubMed

    Mindlin, Sofia; Petrenko, Anatolii; Kurakov, Anton; Beletsky, Alexey; Mardanov, Andrey; Petrova, Mayya

    2016-01-01

    We performed whole-genome sequencing of five permafrost strains of Acinetobacter lwoffii (frozen for 15-3000 thousand years) and analyzed their resistance genes found in plasmids and chromosomes. Four strains contained multiple plasmids (8-12), which varied significantly in size (from 4,135 to 287,630 bp) and genetic structure; the fifth strain contained only two plasmids. All large plasmids and some medium-size and small plasmids contained genes encoding resistance to various heavy metals, including mercury, cobalt, zinc, cadmium, copper, chromium, and arsenic compounds. Most resistance genes found in the ancient strains of A. lwoffii had their closely related counterparts in modern clinical A. lwoffii strains that were also located on plasmids. The vast majority of the chromosomal resistance determinants did not possess complete sets of the resistance genes or contained truncated genes. Comparative analysis of various A. lwoffii and of A. baumannii strains discovered a number of differences between them: (i) chromosome sizes in A. baumannii exceeded those in A. lwoffii by about 20%; (ii) on the contrary, the number of plasmids in A. lwoffii and their total size were much higher than those in A. baumannii; (iii) heavy metal resistance genes in the environmental A. lwoffii strains surpassed those in A. baumannii strains in the number and diversity and were predominantly located on plasmids. Possible reasons for these differences are discussed.

  15. Biodegradation of Phenol by Bacteria Strain Acinetobacter Calcoaceticus PA Isolated from Phenolic Wastewater

    PubMed Central

    Liu, Zhenghui; Xie, Wenyu; Li, Dehao; Peng, Yang; Li, Zesheng; Liu, Shusi

    2016-01-01

    A phenol-degrading bacterium strain PA was successfully isolated from the effluent of petrochemical wastewater. Based on its morphological, physiological and biochemical characteristics, the strain PA was characterized as a Gram-negative, strictly aerobic, nonmotile and short rod-shaped bacterium that utilizes phenol as a sole carbon and energy source. 16S rDNA sequence analysis revealed that this strain is affiliated to Acinetobacter calcoaceticus in the group of Gammaproteobacteria. The strain was efficient in removing 91.6% of the initial 800 mg∙L−1 phenol within 48 h, and had a tolerance of phenol concentration as high as 1700 mg∙L−1. These results indicated that A. calcoaceticus possesses a promising potential in treating phenolic wastewater. PMID:27005648

  16. Genome Sequence of Acinetobacter sp. Strain HA, Isolated from the Gut of the Polyphagous Insect Pest Helicoverpa armigera

    PubMed Central

    Malhotra, Jaya; Dua, Ankita; Saxena, Anjali; Sangwan, Naseer; Mukherjee, Udita; Pandey, Neeti; Rajagopal, Raman; Khurana, Paramjit; Khurana, Jitendra P.

    2012-01-01

    In this study, Acinetobacter sp. strain HA was isolated from the midgut of a fifth-instar larva of Helicoverpa armigera. Here, we report the draft genome sequence (3,125,085 bp) of this strain that consists of 102 contigs, 2,911 predicted coding sequences, and a G+C content of 41%. PMID:22933775

  17. Draft Genome Sequence of Acinetobacter calcoaceticus Strain P23, a Plant Growth-Promoting Bacterium of Duckweed

    PubMed Central

    Hosoyama, Akira; Yamazoe, Atsushi; Morikawa, Masaaki

    2015-01-01

    Acinetobacter calcoaceticus strain P23 is a plant growth-promoting bacterium, which was isolated from the surface of duckweed. We report here the draft genome sequence of strain P23. The genome data will serve as a valuable reference for understanding the molecular mechanism of plant growth promotion in aquatic plants. PMID:25720680

  18. Draft genome sequence of an Acinetobacter genomic species 3 strain harboring a bla(NDM-1) gene.

    PubMed

    Chen, Yong; Cui, Yujun; Pu, Fei; Jiang, Guoqin; Zhao, Xiangna; Yuan, Yanting; Zhao, Wei; Li, Dongfang; Liu, Hui; Li, Yin; Liang, Ting; Xu, Li; Wang, Yan; Song, Qing; Yang, Jiyong; Liang, Long; Yang, Ruifu; Han, Li; Song, Yajun

    2012-01-01

    Here we report the draft genome sequence of one Acinetobacter genomic species 3 strain, D499, which harbors the bla(NDM-1) gene. The total length of the assembled genome is 4,103,824 bp, and 3,896 coding sequences (CDSs) were predicted within the genome. A previously unreported bla(NDM-1)-bearing plasmid was identified in this strain.

  19. [Distribution of blaOXA genes in Acinetobacter baumannii strains: a multicenter study].

    PubMed

    Ciftci, Ihsan Hakkı; Aşık, Gülşah; Karakeçe, Engin; Oksüz, Lütfiye; Yağcı, Server; Sesli Çetin, Emel; Ozdemir, Mehmet; Atasoy, Ali Rıza; Koçoğlu, Esra; Gül, Mustafa; Kurtoğlu, Muhammet Güzel; Köksal Çakırlar, Fatma; Seyrek, Adnan; Berktaş, Mustafa; Gültepe, Bilge; Ayyildiz, Ahmet

    2013-10-01

    Acinetobacter baumannii is the most important agent of nosocomial infections within the Acinetobacter genus. This gram-negative coccobacillus is intrinsically resistant to many antibiotics used in antimicrobial therapy, and capable of developing resistance including carbapenems. The objective of this study was to develop a multiplex real time polymerase chain reaction (qPCR) kit for OXA subgroups in A.baumannii, and to investigate the distribution of OXA subgroups in A.baumannii strains isolated from geographically different regions of Turkey. A total of 834 A.baumannii clinical isolates collected from different state and university medical centers in 13 provinces (Afyonkarahisar, Ankara, Bolu, Elazig, Erzurum, Isparta, Istanbul, Kahramanmaras, Konya, Sakarya, Van) between 2008-2011, were included in the study. The isolates were identified by conventional methods and automated systems [Vitek2 (bioMerieux, ABD) and Phoenix (BD Diagnostic, MD)]. The susceptibility profiles of the isolates were studied with automated systems and standard disc diffusion method. All samples were subjected to qPCR to detect blaOXA-51-like, blaOXA-23-like and blaOXA-58-like genes. A conventional PCR method was also used to detect blaOXA-24-like gene. The resistance rates observed during the study period were as follows: 96.8% for amoxicillin-clavulanate, 86.8% for ciprofloxacin, 74.7% for gentamicin, 71.7% for amikacin, 73.5% for cefaperozone-sulbactam, 72.1% for imipenem and 73% for meropenem. Six hundred and two (72.2 %) isolates were resistant to both imipenem and meropenem. Colistin was found to be the most effective antibiotic against A.baumannii isolates with 100% susceptibility rate. All isolates were positive for blaOXA-51-like, however blaOXA-24-like gene could not be demonstrated in any isolate. Total positivity rates of blaOXA-23-like and blaOXA-58-like genes were found as 53.7% and 12.5%, respectively, while these rates were 74.4% and 17.3% in carbapenem-resistant isolates

  20. Modified CHROMagar Acinetobacter Medium for Direct Detection of Multidrug-Resistant Acinetobacter Strains in Nasal and Rectal Swab Samples

    PubMed Central

    Lee, Jacob; Kim, Taek-Kyung; Park, Min-Jeong; Kim, Han-Sung; Kim, Jae-Seok

    2013-01-01

    This study aimed to investigate whether CHROMagar Acinetobacter medium (CHROMagar, France) in combination with an antimicrobial supplement (modified CHROMagar Acinetobacter; CHROMagar, France) can be used for detecting and isolating multidrug-resistant Acinetobacter species (MRA) in nasal and rectal surveillance cultures. Nasal and rectal swab samples were collected from patients in an intensive care unit at a teaching hospital. The samples were used to inoculate modified CHROMagar Acinetobacter plates, which were examined after 24 and 48 hr of incubation at 37℃. Their susceptibility against the antimicrobial agents meropenem, imipenem, ciprofloxacin, and amikacin was analyzed using the Etest (bioMerieux, France). A total of 406 paired samples (406 nasal swabs and 406 rectal swabs) were obtained from 226 patients, and 120 samples (28 nasal and 28 rectal cultures, 47 nasal cultures only, and 17 rectal cultures only) yielded MRA. Seventy-five MRA isolates (18.5%) were recovered from the 406 nasal samples, and 45 MRA isolates (11.1%) were recovered from the 406 rectal samples. Of the 120 MRA isolates, 3 (2.5%) were detected only after 48 hr of incubation. The use of modified CHROMagar Acinetobacter together with nasal and rectal swabs and 1-day incubation is an effective surveillance tool for detecting MRA colonization. PMID:23667846

  1. Production of S-(+)-ibuprofen from a nitrile compound by Acinetobacter sp. strain AK226.

    PubMed Central

    Yamamoto, K; Ueno, Y; Otsubo, K; Kawakami, K; Komatsu, K

    1990-01-01

    S-(+)-2-(4'-Isobutylphenyl)propionic acid [S-(+)-ibuprofen] was produced from racemic 2-(4'-isobutylphenyl)propionitrile (Ibu-CN) by an isolated bacterial strain, Acinetobacter sp. strain AK226. Ammonium acetate, acetonitrile, or n-butyronitrile as a carbon source in the culture medium was effective for bacterial growth and induction of this activity. The optimum pH of the reaction was around 8.0. S-(+)-Ibuprofen formed from Ibu-CN by resting cells was present in a 95% enantiomeric excess. Acinetobacter sp. strain AK226 appeared to possess a nitrilase for Ibu-CN because 2-(4'-isobutylphenyl)propionamide was not detected in the reaction mixture and 2-(4'-isobutylphenyl)propionamide was not hydrolyzed to S-(+)-ibuprofen. Since S-(+)-ibuprofen was preferentially produced while the R enantiomer of Ibu-CN was left almost intact over the time course of the reaction, the putative nitrilase appeared to be highly specific for the S enantiomer of Ibu-CN. PMID:2285318

  2. Acinetobacter sp. strain Ths, a novel psychrotolerant and alkalitolerant bacterium that utilizes hydrocarbon.

    PubMed

    Yamahira, Keiko; Hirota, Kikue; Nakajima, Kenji; Morita, Naoki; Nodasaka, Yoshinobu; Yumoto, Isao

    2008-09-01

    A novel psychrotolerant, alkalitolerant bacterium, strain Ths, was isolated from a soil sample immersed in hot spring water containing hydrocarbons and grown on a chemically defined medium containing n-tetradecane as the sole carbon source. The isolate grew at 0 degrees C but not at temperatures higher than 45 degrees C; its optimum growth temperature was 27 degrees C. It grew in the pH range of 7-9. The strain utilized C(13)-C(30) n-alkane and fluorene at pH 9 and 4 degrees C. To our knowledge, this is the first report on the bacterium that utilizes a wide range of hydrocarbons at a high pH and a low temperature. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain Ths is closely related to genomic species 6 ATCC 17979 (99.1% similarity), genomic species BJ13/TU14 ATCC 17905 (97.8% similarity), genomic species 9 ATCC 9957 (97.6% similarity) belonging to the genus Acinetobacter and to Acinetobacter calcoaceticus JCM 6842(T) (97.5% similarity). DNA-DNA hybridization revealed that the isolate has 62, 25, 18 and 19% relatedness, respectively, to genomic species 6 ATCC 17979, genomic species BJ13/TU14 ATCC 17905, genomic species 9 ATCC 9957 and A. calcoaceticus, respectively.

  3. Outbreak of Extensively Drug-Resistant Acinetobacter baumannii Indigo-Pigmented Strains

    PubMed Central

    Vilacoba, Elisabet; Almuzara, Marisa; Gulone, Lucia; Rodriguez, Rocio; Pallone, Elida; Bakai, Romina; Centrón, Daniela

    2013-01-01

    Acinetobacter baumannii pigmented strains are not common in clinical settings. Here, we report an outbreak caused by indigo-pigmented A. baumannii strains isolated in an acute care hospital in Argentina from March to September 2012. Pan-PCR assays exposed a unique pattern belonging to the recently described regional CC113B/CC79P clonal complex that confirms the relevant relationships among the indigo-pigmented A. baumannii strains. All of them were extensively drug resistant and harbored different genetic elements associated with horizontal genetic transfer, such as the transposon Tn2006, class 2 integrons, AbaR-type islands, IS125, IS26, strA, strB, florR, and the small recombinase ISCR2 associated with the sul2 gene preceded by ISAba1. PMID:23985923

  4. NDM-1-producing Acinetobacter baumannii ST85 now in Turkey, including one isolate from a Syrian refugee.

    PubMed

    Heydari, Farzad; Mammina, Caterina; Koksal, Fatih

    2015-09-01

    New Delhi metallo-β-lactamase-1 (NDM-1), an acquired class B carbapenemase, is a significant clinical threat owing to the extended hydrolysis of β-lactams including carbapenems. Here, to the best of our knowledge we describe for the first time in Turkey two NDM-1-producing Acinetobacter baumannii isolates recovered from intensive care unit patients. The presence of blaNDM-1 was detected by PCR and confirmed by sequencing. The clonal relationship was assessed by PFGE and multilocus sequence typing. Both isolates were positive for blaNDM-1 and were attributed with the sequence type 85. One isolate was from a Syrian refugee, whereas the second was from a patient who had never travelled outside Turkey. Our findings confirmed that the rapid spread of NDM-1-producing Gram-negative organisms could become a major challenge for the treatment and control of healthcare-associated infections in our geographical area. They suggest also that NDM-1-producing strains and/or their genetic determinants are probably being imported from Syria to neighbouring countries.

  5. Characterization of Carbapenem-Resistant Acinetobacter baumannii Strains Isolated from Hospitalized Patients in Palestine.

    PubMed

    Handal, Regeen; Qunibi, Lulu; Sahouri, Ibrahim; Juhari, Maha; Dawodi, Rula; Marzouqa, Hiyam; Hindiyeh, Musa

    2017-01-01

    The American Centers for Disease Control and Prevention (CDC) recognizes Acinetobacter baumannii as a source of global outbreaks and epidemics especially due to its increasing resistance to commercially available antibiotics. In this study, 69 single patient multidrug resistant isolates collected from all over Palestine, except Gaza, were studied. All the isolates were resistant to all the β-lactam antibiotics including the carbapenems. Of the 69 isolates, 82.6% were positive for blaOXA-23, 14.5% were positive for blaOXA-24, and 3% were positive for blaOXA-58. None were positive for blaOXA-143 and blaOXA-235. In addition, 5.8% and 0% were positive for blaNDM and blaKPC, respectively. Of the 69 isolates, none were positive for the aminoglycoside aphA6 gene while 93% were positive for the aphA1 gene. The acetyltransferases aacC1 and aacA4 genes tested positive in 22% and 13% of the isolates, respectively. The ompA biofilm-producing virulence gene was detected in all isolates. Finally, Multilocus Sequence Typing (MLST) of 13 isolates revealed that more than one strain of A. baumannii was circulating in Palestinian hospitals as results revealed that 7 isolates were of ST208, 2 isolates ST218, 1 isolate ST231, 1 isolate ST348, and 2 new Sequence Types. The detection of these drug resistant pathogens is a reminder of the importance of active surveillance for resistant bacteria in order to prevent their spread in hospital settings.

  6. Isolation and characterization of a newly isolated pyrene-degrading Acinetobacter strain USTB-X.

    PubMed

    Yuan, Haiyan; Yao, Jun; Masakorala, Kanaji; Wang, Fei; Cai, Minmin; Yu, Chan

    2014-02-01

    The pryene-degradation bacterium strain USTB-X was newly isolated from the polycyclic aromatic hydrocarbon (PAH)-contaminated soil in Beijing Coking Plant, China. The strain was identified as Acinetobacter with respect to its 16S rDNA and morphological and physiological characteristics. The strain was Gram-negative, non-mobile, non-acid-fast, and non-spore-forming, short rods in young culture and 0.8-1.6 μm in diameter and 1.2-2.5 μm long in the stationary phase of growth. Strain USTB-X could utilize pyrene, naphthalene, fluorene, phenanthrene, benzene, toluene, ethylbenzene, ethanol, methanol, and Tween 80 as sole source of carbon and energy. The strain could produce biosurfactants which enhanced the removal of pyrene and could remove 63 % of pyrene with an initial concentration of 100 mg·L-1 in 16 days without other substrates. Based on the intermediates analyzed by gas chromatography-mass spectrometry, we also deduced the possible metabolic pathway of strain USTBX for pyrene biodegradation. Results indicated that the strain USTB-X had high potential to enhance the removal of PAHs in contaminated sites.

  7. Whole-genome pyrosequencing of an epidemic multidrug-resistant Acinetobacter baumannii strain belonging to the European clone II group.

    PubMed

    Iacono, Michele; Villa, Laura; Fortini, Daniela; Bordoni, Roberta; Imperi, Francesco; Bonnal, Raoul J P; Sicheritz-Ponten, Thomas; De Bellis, Gianluca; Visca, Paolo; Cassone, Antonio; Carattoli, Alessandra

    2008-07-01

    The whole-genome sequence of an epidemic, multidrug-resistant Acinetobacter baumannii strain (strain ACICU) belonging to the European clone II group and carrying the plasmid-mediated bla(OXA)(-)(58) carbapenem resistance gene was determined. The A. baumannii ACICU genome was compared with the genomes of A. baumannii ATCC 17978 and Acinetobacter baylyi ADP1, with the aim of identifying novel genes related to virulence and drug resistance. A. baumannii ACICU has a single chromosome of 3,904,116 bp (which is predicted to contain 3,758 genes) and two plasmids, pACICU1 and pACICU2, of 28,279 and 64,366 bp, respectively. Genome comparison showed 86.4% synteny with A. baumannii ATCC 17978 and 14.8% synteny with A. baylyi ADP1. A conspicuous number of transporters belonging to different superfamilies was predicted for A. baumannii ACICU. The relative number of transporters was much higher in ACICU than in ATCC 17978 and ADP1 (76.2, 57.2, and 62.5 transporters per Mb of genome, respectively). An antibiotic resistance island, AbaR2, was identified in ACICU and had plausibly evolved by reductive evolution from the AbaR1 island previously described in multiresistant strain A. baumannii AYE. Moreover, 36 putative alien islands (pAs) were detected in the ACICU genome; 24 of these had previously been described in the ATCC 17978 genome, 4 are proposed here for the first time and are present in both ATCC 17978 and ACICU, and 8 are unique to the ACICU genome. Fifteen of the pAs in the ACICU genome encode genes related to drug resistance, including membrane transporters and ex novo acquired resistance genes. These findings provide novel insight into the genetic basis of A. baumannii resistance.

  8. The probability of the Acinetobacter baumannii strain clonal spreading in donor-recipient systems, as confirmed by the molecular analysis of randomly amplified polymorphic DNA.

    PubMed

    Sikora, M; Netsvyetayeva, I; Golas, M; Swoboda-Kopec, E; de Walthoffen, S Walter; Sawicka-Grzelak, A; Pacholczyk, M; Chmura, A; Mlynarczyk, G

    2011-10-01

    Acinetobacter baumannii is an important pathogen widely distributed in the hospital environment and responsible for a variety of nosocomial infections. This micro-organism especially affects patients with impaired host defenses in the intensive care unit. It has been implicated in severe nosocomial infections including bloodstream infections, pneumonia, and meningitides. Those infections are often outbreaks caused by a single clone spreading. The aim of our study was an epidemiological analysis of Acinetobacter baumannii strains isolated from hospitalized liver/kidney transplant donors and recipients. The analyzed material for epidemiological test included 13 A. baumannii strains isolated in 2010 from eight liver/kidney donors and 5 organ recipients. The epidemiological analysis of the isolates was performed by the use of the random amplified polymorphic DNA (RAPD)-polymerase chain reaction method to determine their genetic relatedness. We isolated 9 A. baumannii strains from 8 organ donors. Among this group of isolates, four strains showed the same fingerprints that were classified as one RAPD type 1. The remaining donor isolates revealed differentiated patterns. All strains isolated from recipients formed distinct RAPD types, one of which was identical to the group of four donor strains (RAPD type 1). The clonal spreading of A. baumannii strains was not observed among recipients but we noted a single case of probable transmission of the pathogen from the donor to the recipient.

  9. areABC Genes Determine the Catabolism of Aryl Esters in Acinetobacter sp. Strain ADP1

    PubMed Central

    Jones, Rheinallt M.; Collier, Lauren S.; Neidle, Ellen L.; Williams, Peter A.

    1999-01-01

    Acinetobacter sp. strain ADP1 is able to grow on a range of esters of aromatic alcohols, converting them to the corresponding aromatic carboxylic acids by the sequential action of three inducible enzymes: an areA-encoded esterase, an areB-encoded benzyl alcohol dehydrogenase, and an areC-encoded benzaldehyde dehydrogenase. The are genes, adjacent to each other on the chromosome and transcribed in the order areCBA, were located 3.5 kbp upstream of benK. benK, encoding a permease implicated in benzoate uptake, is at one end of the ben-cat supraoperonic cluster for benzoate catabolism by the β-ketoadipate pathway. Two open reading frames which may encode a transcriptional regulator, areR, and a porin, benP, separate benK from areC. Each are gene was individually expressed to high specific activity in Escherichia coli. The relative activities against different substrates of the cloned enzymes were, within experimental error, identical to that of wild-type Acinetobacter sp. strain ADP1 grown on either benzyl acetate, benzyl alcohol, or 4-hydroxybenzyl alcohol as the carbon source. The substrate preferences of all three enzymes were broad, encompassing a range of substituted aromatic compounds and in the case of the AreA esterase, different carboxylic acids. The areA, areB, and areC genes were individually disrupted on the chromosome by insertion of a kanamycin resistance cassette, and the rates at which the resultant strains utilized substrates of the aryl ester catabolic pathway were severely reduced as determined by growth competitions between the mutant and wild-type strains. PMID:10419955

  10. Unravelling the genome of long chain N-acylhomoserine lactone-producing Acinetobacter sp. strain GG2 and identification of its quorum sensing synthase gene

    PubMed Central

    How, Kah Yan; Hong, Kar-Wai; Sam, Choon-Kook; Koh, Chong-Lek; Yin, Wai-Fong; Chan, Kok-Gan

    2015-01-01

    Myriad proteobacteria use N-acyl homoserine lactone (AHL) molecules as quorum sensing (QS) signals to regulate different physiological functions, including virulence, antibiotic production, and biofilm formation. Many of these proteobacteria possess LuxI/LuxR system as the QS mechanism. Recently, we reported the 3.89 Mb genome of Acinetobacter sp. strain GG2. In this work, the genome of this long chain AHL-producing bacterium was unravelled which led to the molecular characterization of luxI homologue, designated as aciI. This 552 bp gene was cloned and overexpressed in Escherichia coli BL21(DE3). The purified protein was ∼20.5 kDa and is highly similar to several autoinducer proteins of LuxI family among Acinetobacter species. To verify the AHL synthesis activity of this protein, high-resolution liquid chromatography–mass spectrometry analysis revealed the production of 3-oxo-dodecanoyl-homoserine lactone and 3-hydroxy-dodecanoyl-homoserine lactone from induced E. coli harboring the recombinant AciI. Our data show for the first time, the cloning and characterization of the luxI homologue from Acinetobacter sp. strain GG2, and confirmation of its AHLs production. These data are of great significance as the annotated genome of strain GG2 has provided a valuable insight in the study of autoinducer molecules and its roles in QS mechanism of the bacterium. PMID:25926817

  11. Genomic and transcriptome analysis of triclosan response of a multidrug-resistant Acinetobacter baumannii strain, MDR-ZJ06.

    PubMed

    Pi, Borui; Yu, Dongliang; Hua, Xiaoting; Ruan, Zhi; Yu, Yunsong

    2017-03-01

    During the last decade, an increasing amount of attention has focused on the potential threat of triclosan to both the human body and environmental ecology. However, the role of triclosan in the development of drug resistance and cross resistance is still in dispute ascribed to largely unknown of triclosan resistance mechanism. In this work, Acinetobacter baumannii MDR-ZJ06, a multidrug-resistant strain, was induced by triclosan, and the genomic variation and transcriptional levels were investigated, respectively. The comparative transcriptomic analysis found that several general protective mechanisms were enhanced under the triclosan condition, including responses to reactive oxygen species and cell membrane damage. Meanwhile, all of the detected fifteen single nucleotide polymorphisms were not directly associated triclosan tolerance. In summary, this work revealed the crucial role of the general stress response in A. baumannii under a triclosan stress condition, which informs a more comprehensive understanding of the role of triclosan in the spread of drug-resistant bacteria.

  12. Genome Sequence of vB_AbaS_TRS1, a Viable Prophage Isolated from Acinetobacter baumannii Strain A118.

    PubMed

    Turner, Dann; Wand, Matthew E; Sutton, J Mark; Centron, Daniela; Kropinski, Andrew M; Reynolds, Darren M

    2016-10-13

    A novel temperate phage, vB_AbaS_TRS1, was isolated from cultures of Acinetobacter baumannii strain A118 that had been exposed to mitomycin C. Phage TRS1 belongs to the Siphoviridae family of bacteriophages and encapsulates a 40,749-bp genome encoding 70 coding sequences and a single tRNA.

  13. Genome Sequence of vB_AbaS_TRS1, a Viable Prophage Isolated from Acinetobacter baumannii Strain A118

    PubMed Central

    Turner, Dann; Wand, Matthew E.; Sutton, J. Mark; Centron, Daniela; Kropinski, Andrew M.

    2016-01-01

    A novel temperate phage, vB_AbaS_TRS1, was isolated from cultures of Acinetobacter baumannii strain A118 that had been exposed to mitomycin C. Phage TRS1 belongs to the Siphoviridae family of bacteriophages and encapsulates a 40,749-bp genome encoding 70 coding sequences and a single tRNA. PMID:27738026

  14. Draft Genome Sequences of Seven Multidrug-Resistant Acinetobacter baumannii Strains, Isolated from Respiratory Samples in Spain

    PubMed Central

    Labrador-Herrera, Gema; Álvarez, Rocío; López-Rojas, Rafael; Smani, Younes; Cebrero-Cangueiro, Tania; Rueda, Antonio; Pérez Florido, Javier; Pachón-Ibáñez, María Eugenia

    2016-01-01

    The draft genome sequences of seven multidrug-resistant Acinetobacter baumannii clinical strains belonging to sequence types ST-208 and ST-218 are reported in this study. They were isolated from tracheobronchial aspirate of mechanically ventilated adult patients admitted to the intensive care unit of a Spanish tertiary hospital during 2010 to 2011. PMID:27034482

  15. Simultaneous Microcystis Algicidal and Microcystin Degrading Capability by a Single Acinetobacter Bacterial Strain.

    PubMed

    Li, Hong; Ai, Hainan; Kang, Li; Sun, Xingfu; He, Qiang

    2016-11-01

    Measures for removal of toxic harmful algal blooms often cause lysis of algal cells and release of microcystins (MCs). In this study, Acinetobacter sp. CMDB-2 that exhibits distinct algal lysing activity and MCs degradation capability was isolated. The physiological response and morphological characteristics of toxin-producing Microcystis aeruginosa, the dynamics of intra- and extracellular MC-LR concentration were studied in an algal/bacterial cocultured system. The results demonstrated that Acinetobacter sp. CMDB-2 caused thorough decomposition of algal cells and impairment of photosynthesis within 24 h. Enhanced algal lysis and MC-LR release appeared with increasing bacterial density from 1 × 10(3) to 1 × 10(7) cells/mL; however, the MC-LR was reduced by nearly 94% within 14 h irrespective of bacterial density. Measurement of extracellular and intracellular MC-LR revealed that the toxin was decreased by 92% in bacterial cell incubated systems relative to control and bacterial cell-free filtrate systems. The results confirmed that the bacterial metabolite caused 92% lysis of Microcystis aeruginosa cells, whereas the bacterial cells were responsible for approximately 91% reduction of MC-LR. The joint efforts of the bacterium and its metabolite accomplished the sustainable removal of algae and MC-LR. This is the first report of a single bacterial strain that achieves these dual actions.

  16. Production and characterization of L-fucose dehydrogenase from newly isolated Acinetobacter sp. strain SA-134.

    PubMed

    Ohshiro, Takashi; Morita, Noriyuki

    2014-01-01

    Microorganisms producing L-fucose dehydrogenase were screened from soil samples, and one of the isolated bacterial strains SA-134 was identified as Acinetobacter sp. by 16S rDNA gene analysis. The strain grew well utilizing L-fucose as a sole source of carbon, but all other monosaccharides tested such as D-glucose and D-arabinose did not support the growth of the strain in the absence of L-fucose. D-Arabinose inhibited the growth even in the culture medium containing L-fucose. Although the strain grew on some organic acids and amino acids such as citric acid and L-alanine as sole sources of carbon, the enzyme was produced only in the presence of L-fucose. The fucose dehydrogenase was purified to apparently homogeneity from the strain, and the native enzyme was a monomer of 25 kD. L-Fucose and D-arabinose were good substrates for the enzyme, but L-galactose was a poor substrate. The enzyme acted on both NAD(+) and NADP(+) in the similar manner.

  17. Genome-wide recombination drives diversification of epidemic strains of Acinetobacter baumannii.

    PubMed

    Snitkin, Evan S; Zelazny, Adrian M; Montero, Clemente I; Stock, Frida; Mijares, Lilia; Murray, Patrick R; Segre, Julie A

    2011-08-16

    Acinetobacter baumannii is an emerging human pathogen and a significant cause of nosocomial infections among hospital patients worldwide. The enormous increase in multidrug resistance among hospital isolates and the recent emergence of pan-drug-resistant strains underscores the urgency to understand how A. baumannii evolves in hospital environments. To this end, we undertook a genomic study of a polyclonal outbreak of multidrug-resistant A. baumannii at the research-based National Institutes of Health Clinical Center. Comparing the complete genome sequences of the three dominant outbreak strain types enabled us to conclude that, despite all belonging to the same epidemic lineage, the three strains diverged before their arrival at the National Institutes of Health. The simultaneous presence of three divergent strains from this lineage supports its increasing prevalence in international hospitals and suggests an ongoing adaptation to the hospital environment. Further genomic comparisons uncovered that much of the diversification that occurred since the divergence of the three outbreak strains was mediated by homologous recombination across 20% of their genomes. Inspection of recombinant regions revealed that several regions were associated with either the loss or swapping out of genes encoding proteins that are exposed to the cell surface or that synthesize cell-surface molecules. Extending our analysis to a larger set of international clinical isolates revealed a previously unappreciated ability of A. baumannii to vary surface molecules through horizontal gene transfer, with subsequent intraspecies dissemination by homologous recombination. These findings have immediate implications in surveillance, prevention, and treatment of A. baumannii infections.

  18. Whole-Genome Sequence of a Colombian Acinetobacter baumannii Strain, a Coproducer of OXA-72 and OXA-255-Like Carbapenemases

    PubMed Central

    Saavedra, Sandra Yamile; Prada-Cardozo, Diego; Pérez-Cardona, Hermes; Hidalgo, Andrea Melissa; González, María Nilse; Reguero, María T.; Valenzuela de Silva, Emilia M.; Mantilla, José R.; Falquet, Laurent; Barreto-Hernández, Emiliano; Duarte, Carolina

    2017-01-01

    ABSTRACT Colombian Acinetobacter baumannii strain ST920 was isolated from the sputum of a 68-year-old male patient. This isolate possessed blaOXA-72 and blaOXA-255-like genes. The assembled genome contained 4,104,098 pb and 38.79% G+C content. This is the first case reported of the coproduction (blaOXA-72 and blaOXA-255-like) of carbapenem-hydrolyzing class D β-lactamases (CHDLs) in Acinetobacter baumannii. PMID:28209815

  19. Synergistic Effects and Antibiofilm Properties of Chimeric Peptides against Multidrug-Resistant Acinetobacter baumannii Strains

    PubMed Central

    Gopal, Ramamourthy; Kim, Young Gwon; Lee, Jun Ho; Lee, Seog Ki; Chae, Jeong Don; Son, Byoung Kwan; Seo, Chang Ho

    2014-01-01

    The increasing prevalence of drug-resistant pathogens highlights the need to identify novel antibiotics. Here we investigated the efficacies of four new antimicrobial peptides (AMPs) for potential drug development. The antibacterial activities, synergistic effects, and antibiofilm properties of the four chimeric AMPs were tested against Acinetobacter baumannii, an emerging Gram-negative, nosocomial, drug-resistant pathogen. Nineteen A. baumannii strains resistant to ampicillin, cefotaxime, ciprofloxacin, tobramycin, and erythromycin were isolated at a hospital from patients with cholelithiasis. All four peptides exhibited significant antibacterial effects (MIC = 3.12 to 12.5 μM) against all 19 strains, whereas five commercial antibiotics showed little or no activity against the same pathogens. An exception was polymyxin, which was effective against all of the strains tested. Each of the peptides showed synergy against one or more strains when administered in combination with cefotaxime, ciprofloxacin, or erythromycin. The peptides also exhibited an ability to prevent biofilm formation, which was not seen with cefotaxime, ciprofloxacin, or erythromycin, though polymyxin also inhibited biofilm formation. Indeed, when administered in combination with ciprofloxacin, the AMP HPMA exerted a potent synergistic effect against A. baumannii biofilm formation. Collectively, our findings indicate that the AMPs tested have no cytotoxicity but possess potent antibacterial and antibiofilm activities and may act synergistically with commercial antibiotics. PMID:24366740

  20. The Genetic Analysis of an Acinetobacter johnsonii Clinical Strain Evidenced the Presence of Horizontal Genetic Transfer

    PubMed Central

    Montaña, Sabrina; Schramm, Sareda T. J.; Traglia, German Matías; Chiem, Kevin; Parmeciano Di Noto, Gisela; Almuzara, Marisa; Barberis, Claudia; Vay, Carlos; Quiroga, Cecilia; Tolmasky, Marcelo E.; Iriarte, Andrés; Ramírez, María Soledad

    2016-01-01

    Acinetobacter johnsonii rarely causes human infections. While most A. johnsonii isolates are susceptible to virtually all antibiotics, strains harboring a variety of β-lactamases have recently been described. An A. johnsonii Aj2199 clinical strain recovered from a hospital in Buenos Aires produces PER-2 and OXA-58. We decided to delve into its genome by obtaining the whole genome sequence of the Aj2199 strain. Genome comparison studies on Aj2199 revealed 240 unique genes and a close relation to strain WJ10621, isolated from the urine of a patient in China. Genomic analysis showed evidence of horizontal genetic transfer (HGT) events. Forty-five insertion sequences and two intact prophages were found in addition to several resistance determinants such as blaPER-2, blaOXA-58, blaTEM-1, strA, strB, ereA, sul1, aacC2 and a new variant of blaOXA-211, called blaOXA-498. In particular, blaPER-2 and blaTEM-1 are present within the typical contexts previously described in the Enterobacteriaceae family. These results suggest that A. johnsonii actively acquires exogenous DNA from other bacterial species and concomitantly becomes a reservoir of resistance genes. PMID:27548264

  1. The Genetic Analysis of an Acinetobacter johnsonii Clinical Strain Evidenced the Presence of Horizontal Genetic Transfer.

    PubMed

    Montaña, Sabrina; Schramm, Sareda T J; Traglia, German Matías; Chiem, Kevin; Parmeciano Di Noto, Gisela; Almuzara, Marisa; Barberis, Claudia; Vay, Carlos; Quiroga, Cecilia; Tolmasky, Marcelo E; Iriarte, Andrés; Ramírez, María Soledad

    2016-01-01

    Acinetobacter johnsonii rarely causes human infections. While most A. johnsonii isolates are susceptible to virtually all antibiotics, strains harboring a variety of β-lactamases have recently been described. An A. johnsonii Aj2199 clinical strain recovered from a hospital in Buenos Aires produces PER-2 and OXA-58. We decided to delve into its genome by obtaining the whole genome sequence of the Aj2199 strain. Genome comparison studies on Aj2199 revealed 240 unique genes and a close relation to strain WJ10621, isolated from the urine of a patient in China. Genomic analysis showed evidence of horizontal genetic transfer (HGT) events. Forty-five insertion sequences and two intact prophages were found in addition to several resistance determinants such as blaPER-2, blaOXA-58, blaTEM-1, strA, strB, ereA, sul1, aacC2 and a new variant of blaOXA-211, called blaOXA-498. In particular, blaPER-2 and blaTEM-1 are present within the typical contexts previously described in the Enterobacteriaceae family. These results suggest that A. johnsonii actively acquires exogenous DNA from other bacterial species and concomitantly becomes a reservoir of resistance genes.

  2. Cometabolism of 3,4-dichlorobenzoate by Acinetobacter sp. strain 4-CB1.

    PubMed Central

    Adriaens, P; Focht, D D

    1991-01-01

    When Acinetobacter sp. strain 4-CB1 was grown on 4-chlorobenzoate (4-CB), it cometabolized 3,4-dichlorobenzoate (3,4-DCB) to 3-chloro-4-hydroxybenzoate (3-C-4-OHB), which could be used as a growth substrate. No cometabolism of 3,4-DCB was observed when Acinetobacter sp. strain 4-CB1 was grown on benzoate. 4-Carboxyl-1,2-benzoquinone was formed as an intermediate from 3,4-DCB and 3-C-4-OHB in aerobic and anaerobic resting-cell incubations and was the major transient intermediate found when cells were grown on 3-C-4-OHB. The first dechlorination step of 3,4-DCB was catalyzed by the 4-CB dehalogenase, while a soluble dehalogenase was responsible for dechlorination of 3-C-4-OHB. Both enzymes were inducible by the respective chlorinated substrates, as indicated by oxygen uptake experiments. The dehalogenase activity on 3-C-4-OHB, observed in crude cell extracts, was 109 and 44 nmol of 3-C-4-OHB min-1 mg of protein-1 under anaerobic and aerobic conditions, respectively. 3-Chloro-4-hydroxybenzoate served as a pseudosubstrate for the 4-hydroxybenzoate monooxygenase by effecting oxygen and NADH consumption without being hydroxylated. Contrary to 4-CB metabolism, the results suggest that 3-C-4-OHB was not metabolized via the protocatechuate pathway. Despite the ability of resting cells grown on 4-CB or 3-C-4-OHB to carry out all of the necessary steps for dehalogenation and catabolism of 3,4-DCB, it appeared that 3,4-DCB was unable to induce the necessary 4-CB dehalogenase for the initial p-dehalogenation step.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2036004

  3. Cloning and Genetic Characterization of dca Genes Required for β-Oxidation of Straight-Chain Dicarboxylic Acids in Acinetobacter sp. Strain ADP1†

    PubMed Central

    Parke, D.; Garcia, M. A.; Ornston, L. N.

    2001-01-01

    A previous study of deletions in the protocatechuate (pca) region of the Acinetobacter sp. strain ADP1 chromosome revealed that genes required for utilization of the six-carbon dicarboxylic acid, adipic acid, are linked to the pca structural genes. To investigate the genes involved in adipate catabolism, a 33.8-kb SacI fragment, which corrects a deletion spanning this region, was cloned. In addition to containing known pca, qui, and pob genes (for protocatechuate, quinate, and 4-hydroxybenzoate dissimilation), clone pZR8000 contained 10 kb of DNA which was the subject of this investigation. A mutant strain of Escherichia coli DH5α, strain EDP1, was isolated that was able to utilize protocatechuate and 4-hydroxybenzoate as growth substrates when EDP1 cells contained pZR8000. Sequence analysis of the new region of DNA on pZR8000 revealed open reading frames predicted to be involved in β-oxidation. Knockouts of three genes implicated in β-oxidation steps were introduced into the chromosome of Acinetobacter sp. strain ADP1. Each of the mutants was unable to grow with adipate. Because the mutants were affected in their ability to utilize additional saturated, straight-chain dicarboxylic acids, the newly discovered 10 kb of DNA was termed the dca (dicarboxylic acid) region. Mutant strains included one with a deletion in dcaA (encoding an acyl coenzyme A [acyl-CoA] dehydrogenase homolog), one with a deletion in dcaE (encoding an enoyl-CoA hydratase homolog), and one with a deletion in dcaH (encoding a hydroxyacyl-CoA dehydrogenase homolog). Data on the dca region should help us probe the functional significance and interrelationships of clustered genetic elements in this section of the Acinetobacter chromosome. PMID:11571189

  4. Cold-active lipolytic activity of psychrotrophic Acinetobacter sp. strain no. 6.

    PubMed

    Suzuki, T; Nakayama, T; Kurihara, T; Nishino, T; Esaki, N

    2001-01-01

    A lipolytic bacterium, strain no. 6, was isolated from Siberian tundra soil. It was a gram-negative coccoid rod capable of growing at 4 degrees C but not at 37 degrees C and was identified as a psychrotrophic strain of the genus Acinetobacter. Strain no. 6 extracellularly produced a lipolytic enzyme that efficiently hydrolyzed triglycerides such as soybean oil during bacterial growth even at 4 degrees C; it degraded 60% of added soybean oil (initial concentration, 1% w/v) after cultivation in LB medium at 4 degrees C for 7 d. Thus, the bacterium is potentially applicable to in-situ bioremediation or bioaugumentation of fat-contaminated cold environments. We partially purified the lipolytic enzyme from the culture filtrate by acetone fractionation and characterized it. The enzyme preparation contained a single species of cold-active lipase with significant activity at 4 degrees C, which was 57% of the activity at the optimum temperature (20 degrees C). The enzyme showed a broad specificity toward the acyl group (C8-C16) of substrate ethyl esters.

  5. A novel competence gene, comP, is essential for natural transformation of Acinetobacter sp. strain BD413.

    PubMed Central

    Porstendörfer, D; Drotschmann, U; Averhoff, B

    1997-01-01

    Acinetobacter sp. strain BD413 (= ATCC 33305), a nutritionally versatile bacterium, has an extremely efficient natural transformation system. Here we describe the generation of eight transformation-affected mutants of Acinetobacter sp. strain BD413 by insertional mutagenesis. These mutants were found by Southern blot analysis and complementation studies to result from single nptII marker insertions at different chromosomal loci. DNA binding and uptake studies with one mutant, T205, revealed that the transformation deficiency of this mutant results from a complete lack of DNA binding and, therefore, uptake activity. A novel competence gene essential for natural transformation, named comP, was cloned by complementation of mutant T205. The nucleotide sequence of comP was determined, and its deduced 15-kDa polypeptide displays significant similarities to type IV pilins. Analysis of the ultrastructure of a transformation-deficient comP mutant and the transformation-competent wild-type strain revealed that both are covered with bundle-forming thin fimbriae (3 to 4 nm in diameter) and individual thick fimbriae (6 nm in diameter). These results provide evidence that the pilinlike ComP is unrelated to the piluslike structures of strain BD413. Taking all data into account, we propose that ComP functions as a major subunit of an organelle acting as a channel or pore mediating DNA binding and/or uptake in Acinetobacter sp. strain BD413. PMID:9361398

  6. Genomic and physiological characterization of a laboratory-isolated Acinetobacter schindleri ACE strain that quickly and efficiently catabolizes acetate.

    PubMed

    Sigala, Juan-Carlos; Suárez, Brisa Paola; Lara, Alvaro R; Borgne, Sylvie Le; Bustos, Patricia; Santamaría, Rosa Isela; González, Víctor; Martinez, Alfredo

    2017-07-01

    An Acinetobacter strain, designated ACE, was isolated in the laboratory. Phylogenetic tests and average nucleotide identity value comparisons suggested that ACE belongs to the species Acinetobacterschindleri. We report for the first time the complete genome sequence of an A. schindleri strain, which consists of a single circular chromosome of 3 001 209 bp with an overall DNA G+C content of 42.9 mol% and six plasmids that account for 266 844 bp of extrachromosomal material. The presence or absence of genes related to carbon catabolism and antibiotic resistance were in agreement with the phenotypic characterization of ACE. This strain grew faster and with a higher biomass yield on acetate than the reference strain Acinetobacter baylyi ADP1. However, ACE did not use aromatic compounds and was unable to grow on common carbon sources, such as glucose, xylose, glycerol or citrate. The gluconeogenic and the catechol pathways are complete in ACE, but compounds that are converted to protocatechuate did not sustain growth since some genes of this pathway are missing. Likewise, this strain could not grow on glucose because it lacks the genes of the Entner-Doudoroff pathway. Minimal inhibitory concentration data showed that ACE was susceptible to most of the antimicrobial agents recommended for the clinical treatment of Acinetobacter spp. Some genes related to a possible human-microbe interaction were found in the ACE genome. ACE is likely to have a low pathogenic risk, as is the case with other A. schindleri strains. These results provide a valuable reference for broadening the knowledge of the biology of Acinetobacter.

  7. Resistance markers and genetic diversity in Acinetobacter baumannii strains recovered from nosocomial bloodstream infections.

    PubMed

    Martins, Hanoch S I; Bomfim, Maria Rosa Q; França, Rafaela O; Farias, Luiz M; Carvalho, Maria Auxiliadora R; Serufo, José Carlos; Santos, Simone G

    2014-01-28

    In this study, phenotypic and genotypic methods were used to detect metallo-β-lactamases, cephalosporinases and oxacillinases and to assess genetic diversity among 64 multiresistant Acinetobacter baumannii strains recovered from blood cultures in five different hospitals in Brazil from December 2008 to June 2009. High rates of resistance to imipenem (93.75%) and polymyxin B (39.06%) were observed using the disk diffusion (DD) method and by determining the minimum inhibitory concentration (MIC). Using the disk approximation method, thirty-nine strains (60.9%) were phenotypically positive for class D enzymes, and 51 strains (79.6%) were positive for cephalosporinase (AmpC). Using the E-test, 60 strains (93.75%) were positive for metallo-β-lactamases (MβLs). All strains were positive for at least one of the 10 studied genes; 59 (92.1%) contained blaVIM-1, 79.6% contained blaAmpC, 93.7% contained blaOXA23 and 84.3% contained blaOXA51. Enterobacteria Repetitive Intergenic Consensus (ERIC)-PCR analysis revealed a predominance of certain clones that differed from each other. However, the same band pattern was observed in samples from the different hospitals studied, demonstrating correlation between the genotypic and phenotypic results. Thus, ERIC-PCR is an appropriate method for rapidly clustering genetically related isolates. These results suggest that defined clonal clusters are circulating within the studied hospitals. These results also show that the prevalence of MDR A. baumannii may vary among clones disseminated in specific hospitals, and they emphasize the importance of adhering to appropriate infection control measures.

  8. Fatty aldehyde dehydrogenases in Acinetobacter sp. strain HO1-N: role in hexadecanol metabolism.

    PubMed Central

    Singer, M E; Finnerty, W R

    1985-01-01

    The role of fatty aldehyde dehydrogenases (FALDHs) in hexadecane and hexadecanol metabolism was studied in Acinetobacter sp. strain HO1-N. Two distinct FALDHs were demonstrated in Acinetobacter sp. strain HO1-N: a membrane-bound, NADP-dependent FALDH activity induced 5-, 15-, and 9-fold by growth on hexadecanol, dodecyl aldehyde, and hexadecane, respectively, and a constitutive, NAD-dependent, membrane-localized FALDH. The NADP-dependent FALDH exhibited apparent Km and Vmax values for decyl aldehyde of 5.0, 13.0, 18.0, and 18.3 microM and 537.0, 500.0, 25.0, and 38.0 nmol/min in hexadecane-, hexadecanol-, ethanol-, palmitate-grown cells, respectively. FALDH isozymes ald-a, ald-b, and ald-c were demonstrated by gel electrophoresis in extracts of hexadecane- and hexadecanol-grown cells. ald-a, ald-b, and ald-d were present in dodecyl aldehyde-grown cells, while palmitate-grown control cells contained ald-b and ald-d. Dodecyl aldehyde-negative mutants were isolated and grouped into two phenotypic classes based on growth: class 1 mutants were hexadecane and hexadecanol negative and class 2 mutants were hexadecane and hexadecanol positive. Specific activity of NADP-dependent FALDH in Ald21 (class 1 mutant) was 85% lower than that of wild-type FALDH, while the specific activity of Ald24 (class 2 mutant) was 55% greater than that of wild-type FALDH. Ald21R, a dodecyl aldehyde-positive revertant able to grow on hexadecane, hexadecanol, and dodecyl aldehyde, exhibited a 100% increase in the specific activity of the NADP-dependent FALDH. The oxidation of [3H]hexadecane byAld21 yielded the accumulation of 61% more fatty aldehyde than the wild type, while Ald24 accumulated 27% more fatty aldehyde, 95% more fatty alcohol, and 65% more wax ester than the wild type. This study provides genetic and physiological evidence for the role of fatty aldehyde as an essential metabolic intermediate and NADP-dependent FALDH as a key enzyme in the dissimilation of hexadecane, hexadecanol

  9. Effectiveness of hand-cleansing agents for removing Acinetobacter baumannii strain from contaminated hands.

    PubMed

    Cardoso, C L; Pereira, H H; Zequim, J C; Guilhermetti, M

    1999-08-01

    The effectiveness of hand-cleansing agents (plain liquid soap, 70% ethyl alcohol, 10% povidone-iodine, and 4% chlorhexidine gluconate) for removing a hospital strain of Acinetobacter baumannii from artificially contaminated hands of 5 volunteers was studied. The experiments were performed by using a Latin square statistical design, with two 5 x 4 randomized blocks, and the results were estimated by ANOVA. In the first and second blocks, the fingertips of the volunteers were contaminated with approximately 10(3) colony-forming units (light contamination hand) and 10(6) colony-forming units (heavy contamination hand), respectively. In the first block, all products tested were effective, almost completely removing the microbial population of A baumannii artificially applied to the hands. In the second block, the use of hand-cleansing agents resulted in 91.36% (4% chlorhexidine), 92.33% (liquid soap), 98.49% (10% povidone-iodine), and 98.93% (70% ethyl alcohol) reduction in counts of A baumannii cells applied to the fingertips. The ethyl alcohol and povidone-iodine had significantly higher removal rates than plain soap and chlorhexidine (P <.05). These results suggest that 70% ethyl alcohol and 10% povidone-iodine may be the most effective hand-cleansing agents for removing A baumannii strain from heavily contaminated hands (10(6) colony-forming units/fingertip).

  10. In vivo protein interaction network analysis reveals porin-localized antibiotic inactivation in Acinetobacter baumannii strain AB5075.

    PubMed

    Wu, Xia; Chavez, Juan D; Schweppe, Devin K; Zheng, Chunxiang; Weisbrod, Chad R; Eng, Jimmy K; Murali, Ananya; Lee, Samuel A; Ramage, Elizabeth; Gallagher, Larry A; Kulasekara, Hemantha D; Edrozo, Mauna E; Kamischke, Cassandra N; Brittnacher, Mitchell J; Miller, Samuel I; Singh, Pradeep K; Manoil, Colin; Bruce, James E

    2016-11-11

    The nosocomial pathogen Acinetobacter baumannii is a frequent cause of hospital-acquired infections worldwide and is a challenge for treatment due to its evolved resistance to antibiotics, including carbapenems. Here, to gain insight on A. baumannii antibiotic resistance mechanisms, we analyse the protein interaction network of a multidrug-resistant A. baumannii clinical strain (AB5075). Using in vivo chemical cross-linking and mass spectrometry, we identify 2,068 non-redundant cross-linked peptide pairs containing 245 intra- and 398 inter-molecular interactions. Outer membrane proteins OmpA and YiaD, and carbapenemase Oxa-23 are hubs of the identified interaction network. Eighteen novel interactors of Oxa-23 are identified. Interactions of Oxa-23 with outer membrane porins OmpA and CarO are verified with co-immunoprecipitation analysis. Furthermore, transposon mutagenesis of oxa-23 or interactors of Oxa-23 demonstrates changes in meropenem or imipenem sensitivity in strain AB5075. These results provide a view of porin-localized antibiotic inactivation and increase understanding of bacterial antibiotic resistance mechanisms.

  11. Spreading of AbaR-type genomic islands in multidrug resistance Acinetobacter baumannii strains belonging to different clonal complexes.

    PubMed

    Ramírez, María Soledad; Vilacoba, Elisabet; Stietz, María Silvina; Merkier, Andrea Karina; Jeric, Paola; Limansky, Adriana S; Márquez, Carolina; Bello, Helia; Catalano, Mariana; Centrón, Daniela

    2013-07-01

    In order to determine the occurrence of AbaR-type genomic island in multidrug resistant Acinetobacter baumannii (MDRAb) strains circulating in Argentina, Uruguay, and Chile, we studied 51 MDRAb isolates recovered from several hospitals over 30 years. AbaR-type genomic resistance islands were found in 36 MDRAb isolates since 1986 till now. MLST technique allowed us to identify the presence of four different Clonal Complexes (109, 104, 119, 113) among the positive AbaR-type island positive strains. This is the first description of AbaR-type islands in the CC104 and CC113 that are the most widespread Clonal Complexes in Argentina. In addition, PCR mapping exposed different arrays to those previously described, evidencing the plasticity of this island. Our results evidence a widespread distribution of the AbaR-type genomic islands along the time in the MDRAb population, including the epidemic global clone 1 (GC1) as well as different clonal complexes to those already described in the literature.

  12. In vivo protein interaction network analysis reveals porin-localized antibiotic inactivation in Acinetobacter baumannii strain AB5075

    PubMed Central

    Wu, Xia; Chavez, Juan D.; Schweppe, Devin K.; Zheng, Chunxiang; Weisbrod, Chad R.; Eng, Jimmy K.; Murali, Ananya; Lee, Samuel A.; Ramage, Elizabeth; Gallagher, Larry A.; Kulasekara, Hemantha D.; Edrozo, Mauna E.; Kamischke, Cassandra N.; Brittnacher, Mitchell J.; Miller, Samuel I.; Singh, Pradeep K.; Manoil, Colin; Bruce, James E.

    2016-01-01

    The nosocomial pathogen Acinetobacter baumannii is a frequent cause of hospital-acquired infections worldwide and is a challenge for treatment due to its evolved resistance to antibiotics, including carbapenems. Here, to gain insight on A. baumannii antibiotic resistance mechanisms, we analyse the protein interaction network of a multidrug-resistant A. baumannii clinical strain (AB5075). Using in vivo chemical cross-linking and mass spectrometry, we identify 2,068 non-redundant cross-linked peptide pairs containing 245 intra- and 398 inter-molecular interactions. Outer membrane proteins OmpA and YiaD, and carbapenemase Oxa-23 are hubs of the identified interaction network. Eighteen novel interactors of Oxa-23 are identified. Interactions of Oxa-23 with outer membrane porins OmpA and CarO are verified with co-immunoprecipitation analysis. Furthermore, transposon mutagenesis of oxa-23 or interactors of Oxa-23 demonstrates changes in meropenem or imipenem sensitivity in strain AB5075. These results provide a view of porin-localized antibiotic inactivation and increase understanding of bacterial antibiotic resistance mechanisms. PMID:27834373

  13. Draft Genome Sequences of Acinetobacter baumannii Strains Harboring the blaNDM-1 Gene Isolated in Lebanon from Civilians Wounded during the Syrian Civil War.

    PubMed

    Tokajian, Sima; Eisen, Jonathan A; Jospin, Guillaume; Hamze, Monzer; Rafei, Rayane; Salloum, Tamara; Ibrahim, Joe; Coil, David A

    2016-01-28

    We present here the draft genome sequences of multidrug-resistant blaNDM-1-positive Acinetobacter baumannii strains ACMH-6200 and ACMH-6201, isolated in north Lebanon from civilians wounded during the Syrian civil war. The draft genomes were contained in 217 contigs for ACMH-6200 and 83 contigs for ACMH-6201, including a combined 3,997,237 bases for ACMH-6200 and 3,983,110 bases for ACMH-6201, with 39% and 38.9% G+C content, respectively.

  14. AmiE, a novel N-acylhomoserine lactone acylase belonging to the amidase family, from the activated-sludge isolate Acinetobacter sp. strain Ooi24.

    PubMed

    Ochiai, Seiji; Yasumoto, Sera; Morohoshi, Tomohiro; Ikeda, Tsukasa

    2014-11-01

    Many Gram-negative bacteria use N-acyl-l-homoserine lactones (AHLs) as quorum-sensing signal molecules. We have reported that Acinetobacter strains isolated from activated sludge have AHL-degrading activity. In this study, we cloned the amiE gene as an AHL-degradative gene from the genomic library of Acinetobacter sp. strain Ooi24. High-performance liquid chromatography analysis revealed that AmiE functions as an AHL acylase, which hydrolyzes the amide bond of AHL. AmiE showed a high level of degrading activity against AHLs with long acyl chains but no activity against AHLs with acyl chains shorter than eight carbons. AmiE showed homology with a member of the amidases (EC 3.5.1.4) but not with any known AHL acylase enzymes. An amino acid sequence of AmiE from Ooi24 showed greater than 99% identities with uncharacterized proteins from Acinetobacter ursingii CIP 107286 and Acinetobacter sp. strain CIP 102129, but it was not found in the draft or complete genome sequences of other Acinetobacter strains. The presence of transposase-like genes around the amiE genes of these three Acinetobacter strains suggests that amiE is transferred by a putative transposon. Furthermore, the expression of AmiE in Pseudomonas aeruginosa PAO1 reduced AHL accumulation and elastase activity, which were regulated by AHL-mediated quorum sensing.

  15. Molecular analysis of Acinetobacter baumannii strains isolated in Lebanon using four different typing methods.

    PubMed

    Rafei, Rayane; Dabboussi, Fouad; Hamze, Monzer; Eveillard, Matthieu; Lemarié, Carole; Gaultier, Marie-Pierre; Mallat, Hassan; Moghnieh, Rima; Husni-Samaha, Rola; Joly-Guillou, Marie-Laure; Kempf, Marie

    2014-01-01

    This study analyzed 42 Acinetobacter baumannii strains collected between 2009-2012 from different hospitals in Beyrouth and North Lebanon to better understand the epidemiology and carbapenem resistance mechanisms in our collection and to compare the robustness of pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST), repetitive sequence-based PCR (rep-PCR) and blaOXA-51 sequence-based typing (SBT). Among 31 carbapenem resistant strains, we have detected three carbapenem resistance genes: 28 carried the blaOXA-23 gene, 1 the blaOXA-24 gene and 2 strains the blaOXA-58 gene. This is the first detection of blaOXA-23 and blaOXA-24 in Lebanon. PFGE identified 11 types and was the most discriminating technique followed by rep-PCR (9 types), blaOXA-51 SBT (8 types) and MLST (7 types). The PFGE type A'/ST2 was the dominant genotype in our collection present in Beyrouth and North Lebanon. The clustering agreement between all techniques was measured by adjust Wallace coefficient. An overall agreement has been demonstrated. High values of adjust Wallace coefficient were found with followed combinations: PFGE to predict MLST types  = 100%, PFGE to predict blaOXA-51 SBT = 100%, blaOXA-51 SBT to predict MLST = 100%, MLST to predict blaOXA-51 SBT = 84.7%, rep-PCR to predict MLST = 81.5%, PFGE to predict rep-PCR = 69% and rep-PCR to predict blaOXA-51 SBT = 67.2%. PFGE and MLST are gold standard methods for outbreaks investigation and population structure studies respectively. Otherwise, these two techniques are technically, time and cost demanding. We recommend the use of blaOXA-51 SBT as first typing method to screen isolates and assign them to their corresponding clonal lineages. Repetitive sequence-based PCR is a rapid tool to access outbreaks but careful interpretation of results must be always performed.

  16. Complete Genome Sequence of the Multiresistant Acinetobacter baumannii Strain AbH12O-A2, Isolated during a Large Outbreak in Spain

    PubMed Central

    Merino, M.; Alvarez-Fraga, L.; Gómez, M. J.; Aransay, A. M.; Lavín, J. L.; Chaves, F.

    2014-01-01

    We report the complete genome sequence of Acinetobacter baumannii strain AbH12O-A2, isolated during a large outbreak in Spain. The genome has 3,875,775 bp and 3,526 coding sequences, with 39.4% G+C content. The availability of this genome will facilitate the study of the pathogenicity of the Acinetobacter species. PMID:25395646

  17. [Adhesion and slime production by wild and clinical strains of Acinetobacter baumannii].

    PubMed

    Jachna-Sawicka, Katarzyna; Kleszczyńska, Maja; Gospodarek, Eugenia

    2012-01-01

    Adhesion of bacteria to the surface plays a key role in the development of infection, and is the first stage of biofilm formation. The ability of A. baumannii strains to adhesion and forming biofilms on abiotic surfaces, as well as eucaryotic cells was described.A. baumannii is also capable of secretion of the exopolysaccharide (EPS) - a substance that allows the binding of bacterial cells to the surface, and with each other. The aim of this study was to evaluate the ability of biofilm formation and slime production by wild-type and clinical strains of A. baumannii. We examinated 51 strains ofA. baumannii, including 14 isolated from lower respiratory tract, 17 from wound swabs and 20 from the soil. Adhesion to polystyrene was evaluated by modified Christensen methods and slime production by Ishiguro method. Adhesion to polystyrene was observed in 51,0% of strains, including 70,0% of wild-type and 38,7% of clinical strains (64,7% strains from wound swabs and one strain from lower respiratory tract). Slime production was found in 31,4% of strains, of which the largest (42.9%) group strains were isolated from lower respiratory tract. There was no correlation between production of extracellular slime, and the adhesion of strains to polystyrene. Different levels of expression of virulence factors in A. baumannii strains isolated from different origin indicates their importance in the colonisation ecological niches and the development of infections at various sites.

  18. Prevalence and antimicrobial susceptibility of Acinetobacter spp. isolated from meat.

    PubMed

    Carvalheira, Ana; Casquete, Rocio; Silva, Joana; Teixeira, Paula

    2017-02-21

    The prevalence and antibiotic resistance of Acinetobacter spp. from fifty samples of meat (chicken, turkey, beef and pork) were evaluated. Acinetobacter spp. was recovered from all samples and the clonal relatedness of 223 isolates identified to belong to the genus Acinetobacter was established by PFGE. A high genetic diversity was observed and 166 isolates from different samples, 141 representing different PFGE profiles, were further identified to the species level by rpoB gene sequencing. Thirteen distinct Acinetobacter species were identified among 156 isolates. The remaining ten isolates may represent three putatively novel species since rpoB sequence homologies with type strains of all available described Acinetobacter species, were <95%. The most common species was Acinetobacter guillouiae with a prevalence of 34.9%. However 18.7% of the strains belong to the Acinetobacter baumannii group (n=31) which include the species Acinetobacter baumannii (n=7), Acinetobacter pittii (n=12), Acinetobacter seifertii (n=8) and Acinetobacter nosocomialis (n=4) that are the species most frequently associated with nosocomial infections worldwide. In general, strains were resistant to some of the antimicrobials most frequently used to treat Acinetobacter infections such as piperacillin-tazobactam (64.9% of strains resistant), ceftazidime (43.5%), ciprofloxacin (42.9%), as well as to colistin (41.7%) and polymyxin B (35.1%), the last-resort drugs to treat infections caused by multidrug-resistant Acinetobacter. The percentage of resistant strains to trimethoprim-sulfamethoxazole, tetracycline, aminoglycosides (amikacin and tobramycin) and ampicillin-sulbactam was >10% (23.2%, 23.2%, 14.3%, 12.5%, 12.5%, respectively). However, resistances to meropenem, imipenem and minocycline were only sporadically observed (8.3%, 1.2% and 1.2%, respectively). Overall, 51.2% of the strains were considered as multidrug-resistant (MDR) and 9.6% as extensively drug-resistant (XDR). The prevalence

  19. Molecular Analysis of Acinetobacter baumannii Strains Isolated in Lebanon Using Four Different Typing Methods

    PubMed Central

    Rafei, Rayane; Dabboussi, Fouad; Hamze, Monzer; Eveillard, Matthieu; Lemarié, Carole; Gaultier, Marie-Pierre; Mallat, Hassan; Moghnieh, Rima; Husni-Samaha, Rola; Joly-Guillou, Marie-Laure; Kempf, Marie

    2014-01-01

    This study analyzed 42 Acinetobacter baumannii strains collected between 2009–2012 from different hospitals in Beyrouth and North Lebanon to better understand the epidemiology and carbapenem resistance mechanisms in our collection and to compare the robustness of pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST), repetitive sequence-based PCR (rep-PCR) and blaOXA-51 sequence-based typing (SBT). Among 31 carbapenem resistant strains, we have detected three carbapenem resistance genes: 28 carried the blaOXA-23 gene, 1 the blaOXA-24 gene and 2 strains the blaOXA-58 gene. This is the first detection of blaOXA-23 and blaOXA-24 in Lebanon. PFGE identified 11 types and was the most discriminating technique followed by rep-PCR (9 types), blaOXA-51 SBT (8 types) and MLST (7 types). The PFGE type A'/ST2 was the dominant genotype in our collection present in Beyrouth and North Lebanon. The clustering agreement between all techniques was measured by adjust Wallace coefficient. An overall agreement has been demonstrated. High values of adjust Wallace coefficient were found with followed combinations: PFGE to predict MLST types  = 100%, PFGE to predict blaOXA-51 SBT = 100%, blaOXA-51 SBT to predict MLST = 100%, MLST to predict blaOXA-51 SBT = 84.7%, rep-PCR to predict MLST = 81.5%, PFGE to predict rep-PCR = 69% and rep-PCR to predict blaOXA-51 SBT = 67.2%. PFGE and MLST are gold standard methods for outbreaks investigation and population structure studies respectively. Otherwise, these two techniques are technically, time and cost demanding. We recommend the use of blaOXA-51 SBT as first typing method to screen isolates and assign them to their corresponding clonal lineages. Repetitive sequence-based PCR is a rapid tool to access outbreaks but careful interpretation of results must be always performed. PMID:25541711

  20. CRISPR-cas Subtype I-Fb in Acinetobacter baumannii: Evolution and Utilization for Strain Subtyping

    PubMed Central

    Karah, Nabil; Samuelsen, Ørjan; Zarrilli, Raffaele; Sahl, Jason W.; Wai, Sun Nyunt; Uhlin, Bernt Eric

    2015-01-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) are polymorphic elements found in the genome of some or all strains of particular bacterial species, providing them with a system of acquired immunity against invading bacteriophages and plasmids. Two CRISPR-Cas systems have been identified in Acinetobacter baumannii, an opportunistic pathogen with a remarkable capacity for clonal dissemination. In this study, we investigated the mode of evolution and diversity of spacers of the CRISPR-cas subtype I-Fb locus in a global collection of 76 isolates of A. baumannii obtained from 14 countries and 4 continents. The locus has basically evolved from a common ancestor following two main lineages and several pathways of vertical descent. However, this vertical passage has been interrupted by occasional events of horizontal transfer of the whole locus between distinct isolates. The isolates were assigned into 40 CRISPR-based sequence types (CST). CST1 and CST23-24 comprised 18 and 9 isolates, representing two main sub-clones of international clones CC1 and CC25, respectively. Epidemiological data showed that some of the CST1 isolates were acquired or imported from Iraq, where it has probably been endemic for more than one decade and occasionally been able to spread to USA, Canada, and Europe. CST23-24 has shown a remarkable ability to cause national outbreaks of infections in Sweden, Argentina, UAE, and USA. The three isolates of CST19 were independently imported from Thailand to Sweden and Norway, raising a concern about the prevalence of CST19 in Thailand. Our study highlights the dynamic nature of the CRISPR-cas subtype I-Fb locus in A. baumannii, and demonstrates the possibility of using a CRISPR-based approach for subtyping a significant part of the global population of A. baumannii. PMID:25706932

  1. CRISPR-cas subtype I-Fb in Acinetobacter baumannii: evolution and utilization for strain subtyping.

    PubMed

    Karah, Nabil; Samuelsen, Ørjan; Zarrilli, Raffaele; Sahl, Jason W; Wai, Sun Nyunt; Uhlin, Bernt Eric

    2015-01-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) are polymorphic elements found in the genome of some or all strains of particular bacterial species, providing them with a system of acquired immunity against invading bacteriophages and plasmids. Two CRISPR-Cas systems have been identified in Acinetobacter baumannii, an opportunistic pathogen with a remarkable capacity for clonal dissemination. In this study, we investigated the mode of evolution and diversity of spacers of the CRISPR-cas subtype I-Fb locus in a global collection of 76 isolates of A. baumannii obtained from 14 countries and 4 continents. The locus has basically evolved from a common ancestor following two main lineages and several pathways of vertical descent. However, this vertical passage has been interrupted by occasional events of horizontal transfer of the whole locus between distinct isolates. The isolates were assigned into 40 CRISPR-based sequence types (CST). CST1 and CST23-24 comprised 18 and 9 isolates, representing two main sub-clones of international clones CC1 and CC25, respectively. Epidemiological data showed that some of the CST1 isolates were acquired or imported from Iraq, where it has probably been endemic for more than one decade and occasionally been able to spread to USA, Canada, and Europe. CST23-24 has shown a remarkable ability to cause national outbreaks of infections in Sweden, Argentina, UAE, and USA. The three isolates of CST19 were independently imported from Thailand to Sweden and Norway, raising a concern about the prevalence of CST19 in Thailand. Our study highlights the dynamic nature of the CRISPR-cas subtype I-Fb locus in A. baumannii, and demonstrates the possibility of using a CRISPR-based approach for subtyping a significant part of the global population of A. baumannii.

  2. Effects Exerted by Transcriptional Regulator PcaU from Acinetobacter sp. Strain ADP1

    PubMed Central

    Trautwein, Gaby; Gerischer, Ulrike

    2001-01-01

    Protocatechuate degradation is accomplished in a multistep inducible catabolic pathway in Acinetobacter sp. strain ADP1. The induction is brought about by the transcriptional regulator PcaU in concert with the inducer protocatechuate. PcaU, a member of the new IclR family of transcriptional regulators, was shown to play a role in the activation of transcription at the promoter for the structural pca genes, leaving open the participation of additional activators. In this work we show that there is no PcaU-independent transcriptional activation at the pca gene promoter. The minimal inducer concentration leading to an induction response is 10−5 M protocatechuate. The extent of expression of the pca genes was observed to depend on the nature of the inducing carbon source, and this is assumed to be caused by different internal levels of protocatechuate in the cells. The basal level of expression was shown to be comparatively high and to vary depending on the noninducing carbon source independent of PcaU. In addition to the activating function, in vivo results suggest a repressing function for PcaU at the pca gene promoter in the absence of an elevated inducer concentration. Expression at the pcaU gene promoter is independent of the growth condition but is subject to strong negative autoregulation. We propose a model in which PcaU exerts a repressor function both at its own promoter and at the structural gene promoter and in addition functions as an activator of transcription at the structural gene promoter at elevated inducer concentration. PMID:11208784

  3. Clonal Diversity of Nosocomial Epidemic Acinetobacter baumannii Strains Isolated in Spain▿

    PubMed Central

    Villalón, Pilar; Valdezate, Sylvia; Medina-Pascual, Maria J.; Rubio, Virginia; Vindel, Ana; Saez-Nieto, Juan A.

    2011-01-01

    Acinetobacter baumannii is one of the major pathogens involved in nosocomial outbreaks. The clonal diversity of 729 epidemic strains isolated from 19 Spanish hospitals (mainly from intensive care units) was analyzed over an 11-year period. Pulsed-field gel electrophoresis (PFGE) identified 58 PFGE types that were subjected to susceptibility testing, rpoB gene sequencing, and multilocus sequence typing (MLST). All PFGE types were multidrug resistant; colistin was the only agent to which all pathogens were susceptible. The 58 PFGE types were grouped into 16 clones based on their genetic similarity (cutoff of 80%). These clones were distributed into one major cluster (cluster D), three medium clusters (clusters A, B, and C), and three minor clusters (clusters E, F, and G). The rpoB gene sequencing and MLST results reflected a clonal distribution, in agreement with the PFGE results. The MLST sequence types (STs) (and their percent distributions) were as follows: ST-2 (47.5%), ST-3 (5.1%), ST-15 (1.7%), ST-32 (1.7%), ST-79 (13.6%), ST-80 (20.3%), and ST-81 (10.2%). ST-79, ST-80, and ST-81 and the alleles cpn60-26 and recA29 are described for the first time. International clones I, II, and III were represented by ST-81, ST-2, and ST-3, respectively. ST-79 and ST-80 could be novel emerging clones. This work confirms PFGE and MLST to be complementary tools in clonality studies. Here PFGE was able to demonstrate the monoclonal pattern of most outbreaks, the inter- and intrahospital transmission of bacteria, and their endemic persistence in some wards. MLST allowed the temporal evolution and spatial distribution of Spanish clones to be monitored and permitted international comparisons to be made. PMID:21177889

  4. Activity of cecropin A-melittin hybrid peptides against colistin-resistant clinical strains of Acinetobacter baumannii: molecular basis for the differential mechanisms of action.

    PubMed

    Saugar, José María; Rodríguez-Hernández, María Jesús; de la Torre, Beatriz G; Pachón-Ibañez, María Eugenia; Fernández-Reyes, María; Andreu, David; Pachón, Jerónimo; Rivas, Luis

    2006-04-01

    Acinetobacter baumannii has successfully developed resistance against all common antibiotics, including colistin (polymyxin E), the last universally active drug against this pathogen. The possible widespread distribution of colistin-resistant A. baumannii strains may create an alarming clinical situation. In a previous work, we reported differences in lethal mechanisms between polymyxin B (PXB) and the cecropin A-melittin (CA-M) hybrid peptide CA(1-8)M(1-18) (KWKLFKKIGIGAVLKVLTTGLPALIS-NH2) on colistin-susceptible strains (J. M. Saugar, T. Alarcón, S. López-Hernández, M. López-Brea, D. Andreu, and L. Rivas, Antimicrob. Agents Chemother. 46:875-878, 2002). We now demonstrate that CA(1-8)M(1-18) and three short analogues, namely CA(1-7)M(2-9) (KWKLFKKIGAVLKVL-NH2), its Nalpha-octanoyl derivative (Oct-KWKLFKKIGAVLKVL-NH2), and CA(1-7)M(5-9) (KWKLLKKIGAVLKVL-NH2) are active against two colistin-resistant clinical strains. In vitro, resistance to colistin sulfate was targeted to the outer membrane, as spheroplasts were equally lysed by a given peptide, regardless of their respective level of colistin resistance. The CA-M hybrids were more efficient than colistin in displacing lipopolysaccharide-bound dansyl-polymyxin B from colistin-resistant but not from colistin-susceptible strains. Similar improved performance of the CA-M hybrids in permeation of the inner membrane was observed, regardless of the resistance pattern of the strain. These results argue in favor of a possible use of CA-M peptides, and by extension other antimicrobial peptides with similar features, as alternative chemotherapy in colistin-resistant Acinetobacter infections.

  5. Activity of Cecropin A-Melittin Hybrid Peptides against Colistin-Resistant Clinical Strains of Acinetobacter baumannii: Molecular Basis for the Differential Mechanisms of Action

    PubMed Central

    Saugar, José María; Rodríguez-Hernández, María Jesús; de la Torre, Beatriz G.; Pachón-Ibañez, María Eugenia; Fernández-Reyes, María; Andreu, David; Pachón, Jerónimo; Rivas, Luis

    2006-01-01

    Acinetobacter baumannii has successfully developed resistance against all common antibiotics, including colistin (polymyxin E), the last universally active drug against this pathogen. The possible widespread distribution of colistin-resistant A. baumannii strains may create an alarming clinical situation. In a previous work, we reported differences in lethal mechanisms between polymyxin B (PXB) and the cecropin A-melittin (CA-M) hybrid peptide CA(1-8)M(1-18) (KWKLFKKIGIGAVLKVLTTGLPALIS-NH2) on colistin-susceptible strains (J. M. Saugar, T. Alarcón, S. López-Hernández, M. López-Brea, D. Andreu, and L. Rivas, Antimicrob. Agents Chemother. 46:875-878, 2002). We now demonstrate that CA(1-8)M(1-18) and three short analogues, namely CA(1-7)M(2-9) (KWKLFKKIGAVLKVL-NH2), its Nα-octanoyl derivative (Oct-KWKLFKKIGAVLKVL-NH2), and CA(1-7)M(5-9) (KWKLLKKIGAVLKVL-NH2) are active against two colistin-resistant clinical strains. In vitro, resistance to colistin sulfate was targeted to the outer membrane, as spheroplasts were equally lysed by a given peptide, regardless of their respective level of colistin resistance. The CA-M hybrids were more efficient than colistin in displacing lipopolysaccharide-bound dansyl-polymyxin B from colistin-resistant but not from colistin-susceptible strains. Similar improved performance of the CA-M hybrids in permeation of the inner membrane was observed, regardless of the resistance pattern of the strain. These results argue in favor of a possible use of CA-M peptides, and by extension other antimicrobial peptides with similar features, as alternative chemotherapy in colistin-resistant Acinetobacter infections. PMID:16569836

  6. Genomic sequencing of a strain of Acinetobacter baumannii and potential mechanisms to antibiotics resistance.

    PubMed

    Zhao, Lei; Li, Hongru; Zhu, Ziwen; Wakefield, Mark R; Fang, Yujiang; Ye, Ying

    2017-02-09

    Acinetobacter baumannii has been becoming a great challenge to clinicians due to their resistance to almost all available antibiotics. In this study, we sequenced the genome from a multiple antibiotics resistant Acinetobacter baumannii stain which was named A. baumannii-1isolated from China by SMRT sequencing technology to explore its potential mechanisms to antibiotic resistance. We found that several mechanisms might contribute to the antibiotic resistance of Acinetobacter baumannii. Specifically, we found that SNP in genes associated with nucleotide excision repair and ABC transporter might contribute to its resistance to multiple antibiotics; we also found that specific genes associated with bacterial DNA integration and recombination, DNA-mediated transposition and response to antibiotics might contribute to its resistance to multiple antibiotics; Furthermore, specific genes associated with penicillin and cephalosporin biosynthetic pathway and specific genes associated with CHDL and MBL β-lactamase genes might contribute to its resistance to multiple antibiotics. Thus, the detailed mechanisms by which Acinetobacter baumannii show extensive resistance to multiple antibiotics are very complicated. Such a study might be helpful to develop new strategies to control Acinetobacter baumannii infection.

  7. Draft Genome Sequence of Acinetobacter bereziniae HPC229, a Carbapenem-Resistant Clinical Strain from Argentina Harboring blaNDM-1

    PubMed Central

    Brovedan, Marco; Marchiaro, Patricia M.; Morán-Barrio, Jorgelina; Revale, Santiago; Cameranesi, Marcela; Brambilla, Luciano; Viale, Alejandro M.

    2016-01-01

    We report here the draft genome sequence of an NDM-1-producing Acinetobacter bereziniae clinical strain, HPC229. This strain harbors both plasmid and chromosomal resistance determinants toward different β-lactams and aminoglycosides as well as several types of multidrug efflux pumps, most likely representing an adaptation strategy for survival under different environments. PMID:26966220

  8. Draft Genome Sequence of the Plant Growth–Promoting Rhizobacterium Acinetobacter radioresistens Strain SA188 Isolated from the Desert Plant Indigofera argentea

    PubMed Central

    Lafi, Feras F.; Alam, Intikhab; Bisseling, Ton; Geurts, Rene; Bajic, Vladimir B.

    2017-01-01

    ABSTRACT Acinetobacter radioresistens strain SA188 is a plant endophytic bacterium, isolated from root nodules of the desert plants Indigofera spp., collected in Jizan, Saudi Arabia. Here, we report the 3.2-Mb draft genome sequence of strain SA188, highlighting characteristic pathways for plant growth–promoting activity and environmental adaptation. PMID:28254978

  9. Draft Genome Sequence of Acinetobacter bereziniae HPC229, a Carbapenem-Resistant Clinical Strain from Argentina Harboring blaNDM-1.

    PubMed

    Brovedan, Marco; Marchiaro, Patricia M; Morán-Barrio, Jorgelina; Revale, Santiago; Cameranesi, Marcela; Brambilla, Luciano; Viale, Alejandro M; Limansky, Adriana S

    2016-03-10

    We report here the draft genome sequence of an NDM-1-producing Acinetobacter bereziniae clinical strain, HPC229. This strain harbors both plasmid and chromosomal resistance determinants toward different β-lactams and aminoglycosides as well as several types of multidrug efflux pumps, most likely representing an adaptation strategy for survival under different environments.

  10. Draft Genome Sequence of the Mercury-Resistant Bacterium Acinetobacter idrijaensis Strain MII, Isolated from a Mine-Impacted Area, Idrija, Slovenia

    PubMed Central

    Caballero Pérez, Juan; Cruz Medina, Julio Alfonso; Molina Vera, Carlos; Salas Rosas, Luz María; Limpens Gutiérrez, Citlalli; García Salinas, Isaac; Hernández Ramírez, Miriam Rebeca; Soto Alonso, Gerardo; Cruz Hernández, Andrés; Saldaña Gutiérrez, Carlos; Romero Gómez, Sergio; Pastrana Martínez, Xóchitl; Álvarez Hidalgo, Erika; Gosar, Mateja; Dizdarevič, Tatjana

    2014-01-01

    We report here the first draft assembly for the genome of Acinetobacter idrijaensis strain MII, isolated from the Idrija mercury mine area (Slovenia). This strain shows a strikingly high tolerance to mercury, and the genome sequence shows genes involved in the mechanisms for heavy metal tolerance pathways and multidrug efflux pumps. PMID:25395645

  11. Physiological Conditions Conducive to High Cyanophycin Content in Biomass of Acinetobacter calcoaceticus Strain ADP1

    PubMed Central

    Elbahloul, Yasser; Krehenbrink, Martin; Reichelt, Rudolf; Steinbüchel, Alexander

    2005-01-01

    The effects of the inorganic medium components, the initial pH, the incubation temperature, the oxygen supply, the carbon-to-nitrogen ratio, and chloramphenicol on the synthesis of cyanophycin (CGP) by Acinetobacter calcoaceticus strain ADP1 were studied in a mineral salts medium containing sodium glutamate and ammonium sulfate as carbon and nitrogen sources, respectively. Variation of all these factors resulted in maximum CGP contents of only about 3.5% (wt/wt) of the cell dry matter (CDM), and phosphate depletion triggered CGP accumulation most substantially. However, addition of arginine to the medium as the sole carbon source for growth promoted CGP accumulation most strikingly. This effect was systematically studied, and an optimized phosphate-limited medium containing 75 mM arginine and 10 mM ammonium sulfate yielded a CGP content of 41.4% (wt/wt) of the CDM at 30°C. The CGP content of the cells was further increased to 46.0% (wt/wt) of the CDM by adding 2.5 μg of chloramphenicol per ml of medium in the accumulation phase. These contents are by far the highest CGP contents of bacterial cells ever reported. CGP was easily isolated from the cells by using an acid extraction method, and this CGP contained about equimolar amounts of aspartic acid and arginine and no detectable lysine; the molecular masses ranged from 21 to 29 kDa, and the average molecular mass was about 25 kDa. Transmission electron micrographs of thin sections of cells revealed large CGP granules that frequently had an irregular shape with protuberances at the surface and often severely deformed the cells. A cphI::ΩKm mutant of strain ADP1 with a disrupted putative cyanophycinase gene accumulated significantly less CGP than the wild type accumulated, although the cells expressed cyanophycin synthetase at about the same high level. It is possible that the intact CphI protein is involved in the release of CGP primer molecules from initially synthesized CGP. The resulting lower concentration of

  12. Early dissemination of OXA-72-producing Acinetobacter baumannii strain in Colombia: a case report.

    PubMed

    Saavedra, Sandra Yamile; Cayô, Rodrigo; Gales, Ana Cristina; Leal, Aura Lucia; Saavedra, Carlos Humberto

    2014-01-01

    Nosocomial infections caused by carbapenem-resistant Acinetobacter baumannii isolates have reached epidemic levels in past decades. Currently this microorganism is responsible for outbreaks of difficult eradication and with high mortality rates worldwide. We herein report a rare case of an OXA-72-producing A. baumannii isolate colonizing a 47-year-old male patient with peritonitis due to abdominal stab wound, four years earlier than the first report of this carbapenemase in Acinetobacter pittii in Colombia. Although OXA-72 presents a low prevalence compared with OXA-23, our study demonstrated that A. baumannii isolates carrying the blaOXA-72 gene were present in the hospital environment in Colombia and could act as a reservoir for further spread to other Acinetobacter species, like A. pittii, causing carbapenem-resistance. Copyright © 2014 Elsevier Editora Ltda. All rights reserved.

  13. [Antibiotic resistance of Acinetobacter baumannii strains isolated from clinical specimens in the "Marius Nasta" Pneumology Institute, Bucharest].

    PubMed

    Moisoiu, Adriana; Ionită, Monica; Sârbu, Lăcrămioara; Stoica, Corina; Grigoriu, Liliana

    2014-01-01

    Acinetobacter baumannii (A. baumannii) is one of the leading causes of morbidity and mortality in patients who are in critical condition in hospitals and especially in intensive care units (ICU). Long time considered a bacterium with low virulence, A. baumannii has more recently become a cause for major concern in clinical practice due to its high level of antimicrobial resistance. The extend of infections with Acinetobacter baumannii in ICU is caused by multiple factors, such as mechanical ventilation, invasive procedures, the use of a large number of broad spectrum antibiotics and transmission through the hands of medical staff In this study we evaluated the resistance to antibiotics of 213 non-duplicated strains of A. baumannii isolated in the bacteriology laboratory of the "Marius Nasta" lnstitute of Pneumophtisiology (IPMN) from January 2012 to December 2013. These strains originated from patients in medical wards (56), ICU (143) and surgery (14). Strains identification was performed by classical methods on multitest media and with API kits (Bio Merieux). The antibiotic sensitivity was performed on Mueller-Hinton media in accordance with CLSI2013. Analysis of the resistance to antibiotics was the following: carbenicilin (87.3%), ceftriaxone (87.3%), cefoperazone with sulbactam (84.9%), ceftazidime (79.3%), carbapenems (imipenem and/or meropenem--75.1%), fluoroquinolones (ciprofloxacin and/orlevofloxacin--73.7%), cefepime (66.6%), piperacilin with tazobactam (62.4%), amikacin (50.2%), netilmicin (45%), gentamicin (42.7%) and tobramycin (35.6%). In our study, we only found two strains of Acinetobacter baumannii with resistance to colistin and 70 (32.8%) strains sensitive only to colistin, but resistant to all other antibiotics tested. A. baumannii is a pathogen with rapid spread and extended resistance to even newer antimicrobial agents. Due to its ability to survive in the hospital environment, A. baumannii has the immense potential to cause nosocomial

  14. Comparative genomic analysis of Acinetobacter oleivorans DR1 to determine strain-specific genomic regions and gentisate biodegradation.

    PubMed

    Jung, Jaejoon; Madsen, Eugene L; Jeon, Che Ok; Park, Woojun

    2011-10-01

    The comparative genomics of Acinetobacter oleivorans DR1 assayed with A. baylyi ADP1, A. calcoaceticus PHEA-2, and A. baumannii ATCC 17978 revealed that the incorporation of phage-related genomic regions and the absence of transposable elements have contributed to the large size (4.15 Mb) of the DR1 genome. A horizontally transferred genomic region and a higher proportion of transcriptional regulator- and signal peptide-coding genes were identified as characteristics of the DR1 genome. Incomplete glucose metabolism, metabolic pathways of aromatic compounds, biofilm formation, antibiotics and metal resistance, and natural competence genes were conserved in four compared genomes. Interestingly, only strain DR1 possesses gentisate 1,2-dioxygenase (nagI) and grows on gentisate, whereas other species cannot. Expression of the nagI gene was upregulated during gentisate utilization, and four downstream open reading frames (ORFs) were cotranscribed, supporting the notion that gentisate metabolism is a unique characteristic of strain DR1. The genomic analysis of strain DR1 provides additional insights into the function, ecology, and evolution of Acinetobacter species.

  15. Plant growth-promoting and rhizosphere-competent Acinetobacter rhizosphaerae strain BIHB 723 from the cold deserts of the Himalayas.

    PubMed

    Gulati, Arvind; Vyas, Pratibha; Rahi, Praveen; Kasana, Ramesh Chand

    2009-04-01

    A phosphate-solubilizing bacterial strain BIHB 723 isolated from the rhizosphere of Hippophae rhamnoides was identified as Acinetobacter rhizosphaerae on the basis of phenotypic characteristics, carbon source utilization pattern, fatty acid methyl esters analysis, and 16S rRNA gene sequence. The strain exhibited the plant growth-promoting attributes of inorganic and organic phosphate solubilization, auxin production, 1-aminocyclopropane-1-carboxylate deaminase activity, ammonia generation, and siderophore production. A significant increase in the growth of pea, chickpea, maize, and barley was recorded for inoculations under controlled conditions. Field testing with the pea also showed a significant increment in plant growth and yield. The rifampicin mutant of the bacterial strain effectively colonized the pea rhizosphere without adversely affecting the resident microbial populations.

  16. Study of a hydrocarbon-utilizing and emulsifier-producing Acinetobacter calcoaceticus strain isolated from heating oil.

    PubMed

    Marín, M M; Pedregosa, A M; Ortiz, M L; Laborda, F

    1995-12-01

    Twenty bacterial strains were isolated from a sample of contaminated heating oil and screened for their ability to use petroleum and several common fuels as the sole source of carbon and energy. One of the isolates, named MM5, was able to grow on petroleum derivatives and brought about an emulsification of those compounds. Gas chromatography studies showed that strain MM5 was able to degrade hydrocarbons of heating oil. MM5 has been tentatively identified as a strain of Acinetobacter calcoaceticus. The fine structure of MM5 was examined by transmission electron microscopy. Incubation in the presence of hydrocarbon substrates resulted in the development of intracellular electron-transparent inclusions. These structures were absent in the non-hydrocarbon cultures studied.

  17. Characterization and upregulation of bifunctional phosphoglucomutase/phosphomannomutase enzyme in an exobiopolymer overproducing strain of Acinetobacter haemolyticus.

    PubMed

    Kaur, Taranpreet; Ghosh, Moushumi

    2015-12-01

    Several members of the Acinetobacter spp. produce exobiopolymer (EBP) of considerable biotechnological interest. In a previous study, we reported phosphate removal capacity of EBP produced by Acinetobacter haemolyticus. Insertional mutagenesis was attempted to develop EBP-overproducing strains of A. haemolyticus and mutant MG606 was isolated. In order to understand the underlying mechanism of overproduction, the EBP overproducing mutant MG606 was analyzed and compared with the wild type counterpart for its key EBP synthetic enzymes. The EBP produced by MG606 mutant was 650 mg/L compared to 220 mg/L in its wild type counterpart. Significantly high (p<0.05) levels of phosphoglucomutase/phosphomannomutase (PGM/PMM) in MG606 mutant was noted, whereas activities of other enzymes responsible for EBP synthesis showed no significant change (p>0.05). The up-regulation of PGM/PMM expression in mutant was further confirmed by real time reverse transcriptase (RT)-PCR of PGM/PMM transcripts. The optimal conditions for PGM/PMM activity were found to be 35 °C and pH 7.5; PGM/PMM activity was inhibited by ions such as lithium, zinc, nickel. Further, incubation of cells with a PGM inhibitor (lithium) resulted in a concentration-dependent decrease in EBP production further confirming the role of PGM/PMM overexpression in enhanced EBP production by the mutant. Overall the results of our study indicate a key role of PGM/PMM in enhanced EBP production, as evident from enhanced enzyme activity, increased PGM/PMM transcripts and reduction in EBP synthesis by a PGM inhibitor. We envisage a potential exploitation of the insights so obtained to effectively engineer strains of Acinetobacter for overproducing phosphate binding EBP.

  18. Molecular Characterization of Multidrug Resistant Strains of Acinetobacter baumannii Isolated from Intensive Care Units in West of Iran

    PubMed Central

    Mohajeri, Parviz; Farahani, Abbas

    2017-01-01

    Introduction According to the results of various studies using phenotypic methods, the prevalence of Multidrug Resistant (MDR) Acinetobacter baumannii (A. baumannii) isolates has been increasing worldwide. Pulsed-Field Gel Electrophoresis (PFGE) technique is known as the gold standard method to determine clonal characterization of bacterial species, especially A. baumannii. Aim To determine the clonal relatedness and investigate the prevalence of integron classes 1 and 2 and genes encoding OXA-23 and 24 in A.baumanii isolates. Materials and Methods A cross-sectional study was conducted from November 2011 to January 2013. A total of 140 A.baumannii isolates collected from three hospitals of Kermanshah were considered out of which 75 ICU isolates were included in this study. Antibiotics susceptibility test was done by disk diffusion method. Polymerase Chain Reaction (PCR) was performed in order to detect class 1 and 2 integrons and blaOXA-23-like, blaOXA-24-like genes. Isolates identified as MDR from a total of 75 Intensive Care Units (ICU) strains were subjected to genotyping for clonal relatedness. Results A total of 37 isolates among 75 ICU isolates were identified as MDR. The maximum drug resistance was observed against ceftriaxone, mezlocycline, cefotaxime, piperacilin, ciprofloxacin and imipenem. Frequency of Class 1 and Class 2 Integrons, blaOXA-23-like and blaOXA-24-like genes were 33(44%), 27(36%), 60(80%) and 14(18.6%) respectively. Four clusters with high level of similarity were obtained showing homogeneity among MDR isolates. Conclusion Significant correlation between presence of integrons and resistance to different classes of antibiotic was observed in this study. Monitoring of drug resistance using gene integrase PCR and blaOXA gene by cluster analysis is very important to plan specific infection control measures due to MDR A. baumannii.

  19. Biodegradation of type II pyrethroids and major degraded products by a newly isolated Acinetobacter sp. strain JN8.

    PubMed

    Jin, Zhaoxia; Guo, Qiong; Zhang, Zongshen; Yan, Tongshuai

    2014-08-01

    A Gram-negative aerobic bacterium, designated as JN8, was isolated from activated sludge and soil in a pesticides factory in China. It was found that JN8 had a high capacity for degrading a broad range of type II pyrethroids and utilizing these pyrethroids as the sole carbon source for cell growth. The degradation rates of a 100 mg·L(-1) concentration of β-cypermethrin, cypermethrin, fenpropathrin, fenvalerate, and deltamethrin by JN8 in mineral salt medium were 74.1%, 64.9%, 57.9%, 48.1% and 34.9%, respectively. Strain JN8 was identified as a species of Acinetobacter based on its biochemical properties and 16S rRNA sequence analysis. β-Cypermethrin was degraded by JN8 through hydrolysis of the carboxylester linkage to form 3-phenoxybenzoic acid and 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid, both of which could be further degraded by JN8. JN8 is the first strain of an Acinetobacter species in which pyrethoid-degrading activity has been detected, and such a feature makes it a potential resource for disposal of waste and effluent from pyrethroid manufacturing facilities.

  20. [Investigation of OXA type beta-lactamases and PFGE patterns in Acinetobacter baumannii strains resistant to carbapenems].

    PubMed

    Keyik, Serafettin; Arslan, Uğur; Türk Dağı, Hatice; Seyhan, Tuba; Fındık, Duygu

    2014-10-01

    Acinetobacter baumannii is an important opportunistic and multidrug-resistant pathogen leading to nosocomial infections. Over the last 10 years, a significant and threatening increase in resistance to carbapenems, mainly due to the dissemination of class D beta-lactamases, has been reported in A.baumannii worldwide. The most common types of beta-lactamases causing carbapenem resistance in A.baumannii are the OXA-23, OXA-24, OXA-40, OXA-58 and OXA-143 type serine beta-lactamases. The aim of this study was to investigate the presence of OXA type beta-lactamases in carbapenem-resistant A.baumannii strains and the clonal relationship between the strains. A total of 105 non-duplicate carbapenem-resistant A.baumannii strains isolated from various clinical samples (68 blood, 18 bronchoalveolar lavage, 13 drainage, 3 urine, 2 cerebrospinal fluid and 1 catheter samples) in the Microbiology Laboratories of Selcuk University, Meram (2009-2012) and Selcuklu (2007-2008) Medical School Hospitals, were included in the study. The isolates were identified by conventional methods and Phoenix 100 BD (BD Diagnostic, USA) and Vitek II (bioMerieux, France) automated systems. Carbapenem susceptibility test was performed by Kirby-Bauer disk diffusion method according to the CLSI standards. bla(OXA 23-like), bla(OXA 24-like), bla(OXA 58-like) and bla(OXA 51-like) genes were amplified by multiplex PCR assay and clonal relatedness was investigated by pulsed-field gel electrophoresis (PFGE) using ApaI enzyme. The bla(OXA 51-like) gene was determined in all carbapenem-resistant A.baumannii isolates, while the bla(OXA 23-like) and bla(OXA 58-like) genes were detected in 46.6% and 53.3% of isolates, respectively. However bla(OXA 24-like) gene was not demonstrated in any isolates. bla(OXA 23-like) gene was determined in both Meram and Selcuklu Medical School hospitals, but bla(OXA 58-like) gene was detected only in Meram Medical School hospital. PFGE analysis of the isolates revealed 32 different

  1. Whole-Genome Pyrosequencing of an Epidemic Multidrug-Resistant Acinetobacter baumannii Strain Belonging to the European Clone II Group ▿ †

    PubMed Central

    Iacono, Michele; Villa, Laura; Fortini, Daniela; Bordoni, Roberta; Imperi, Francesco; Bonnal, Raoul J. P.; Sicheritz-Ponten, Thomas; De Bellis, Gianluca; Visca, Paolo; Cassone, Antonio; Carattoli, Alessandra

    2008-01-01

    The whole-genome sequence of an epidemic, multidrug-resistant Acinetobacter baumannii strain (strain ACICU) belonging to the European clone II group and carrying the plasmid-mediated blaOXA-58 carbapenem resistance gene was determined. The A. baumannii ACICU genome was compared with the genomes of A. baumannii ATCC 17978 and Acinetobacter baylyi ADP1, with the aim of identifying novel genes related to virulence and drug resistance. A. baumannii ACICU has a single chromosome of 3,904,116 bp (which is predicted to contain 3,758 genes) and two plasmids, pACICU1 and pACICU2, of 28,279 and 64,366 bp, respectively. Genome comparison showed 86.4% synteny with A. baumannii ATCC 17978 and 14.8% synteny with A. baylyi ADP1. A conspicuous number of transporters belonging to different superfamilies was predicted for A. baumannii ACICU. The relative number of transporters was much higher in ACICU than in ATCC 17978 and ADP1 (76.2, 57.2, and 62.5 transporters per Mb of genome, respectively). An antibiotic resistance island, AbaR2, was identified in ACICU and had plausibly evolved by reductive evolution from the AbaR1 island previously described in multiresistant strain A. baumannii AYE. Moreover, 36 putative alien islands (pAs) were detected in the ACICU genome; 24 of these had previously been described in the ATCC 17978 genome, 4 are proposed here for the first time and are present in both ATCC 17978 and ACICU, and 8 are unique to the ACICU genome. Fifteen of the pAs in the ACICU genome encode genes related to drug resistance, including membrane transporters and ex novo acquired resistance genes. These findings provide novel insight into the genetic basis of A. baumannii resistance. PMID:18411315

  2. Amplification of a single-locus variable-number direct repeats with restriction fragment length polymorphism (DR-PCR/RFLP) for genetic typing of Acinetobacter baumannii strains.

    PubMed

    Nowak-Zaleska, Alicja; Krawczyk, Beata; Kotłowski, Roman; Mikucka, Agnieszka; Gospodarek, Eugenia

    2008-01-01

    In search of an effective DNA typing technique for Acinetobacter baumannii strains for hospital epidemiology use, the performance and convenience of a new target sequence was evaluated. Using known genomic sequences of Acinetobacter baumannii strains AR 319754 and ATCC 17978, we developed single-locus variable-number direct-repeat analysis using polymerase chain reaction-restriction fragment length polymorphism (DR-PCR/RFLP) method. A total of 90 Acinetobacter baumannii strains isolated from patients of the Clinical Hospital in Bydgoszcz, Poland, were examined. Initially, all strains were typed using macrorestriction analysis of the chromosomal DNA by pulsed-field gel electrophoresis (REA-PFGE). Digestion of the chromosomal DNA with the ApaI endonuclease and separation of the fragments by PFGE revealed 21 unique types. Application of DR-PCR/RFLP resulted in recognition of 12 clusters. The results showed that the DR-PCR/RFLP method is less discriminatory than REA-PFGE, however, the novel genotyping method can be used as an alternative technique for generating DNA profiles in epidemiological studies of intra-species genetic relatedness of Acinetobacter baumannii strains.

  3. Multi-omics approach to study global changes in a triclosan-resistant mutant strain of Acinetobacter baumannii ATCC 17978.

    PubMed

    Fernando, Dinesh M; Chong, Patrick; Singh, Manu; Spicer, Victor; Unger, Mark; Loewen, Peter C; Westmacott, Garrett; Kumar, Ayush

    2017-01-01

    Acinetobacter baumannii AB042, a triclosan-resistant mutant strain, was examined for modulated gene expression using whole-genome sequencing, transcriptomics and proteomics in order to understand the mechanism of triclosan resistance as well as its impact on A. baumannii. Data revealed modulated expression of the fatty acid metabolism pathway, co-factors known to play a role in the synthesis of fatty acids, as well as several transcriptional regulators. The membrane composition of the mutant revealed a decrease in C18 with a corresponding increase in C16 fatty acids compared with the parent strain A. baumannii ATCC 17978. These data indicate that A. baumannii responds to triclosan by altering the expression of genes involved in fatty acid metabolism, antibiotic resistance and amino acid metabolism.

  4. Genomic Evolution of Two Acinetobacter baumannii Clinical Strains from ST-2 Clones Isolated in 2000 and 2010 (ST-2_clon_2000 and ST-2_clon_2010).

    PubMed

    López, M; Rueda, A; Florido, J P; Blasco, L; Gato, E; Fernández-García, L; Martínez-Martínez, L; Fernández-Cuenca, F; Pachón, J; Cisneros, J M; Garnacho-Montero, J; Vila, J; Rodríguez-Baño, J; Pascual, A; Bou, G; Tomás, M

    2016-10-20

    Acinetobacter baumannii is a successful nosocomial pathogen due to its ability to persist in hospital environments by acquiring mobile elements such as transposons, plasmids, and phages. In this study, we compared two genomes of A. baumannii clinical strains isolated in 2000 (ST-2_clon_2000) and 2010 (ST-2_clon_2010) from GenBank project PRJNA308422.

  5. Genomic Evolution of Two Acinetobacter baumannii Clinical Strains from ST-2 Clones Isolated in 2000 and 2010 (ST-2_clon_2000 and ST-2_clon_2010)

    PubMed Central

    López, M.; Rueda, A.; Florido, J. P.; Blasco, L.; Gato, E.; Fernández-García, L.; Martínez-Martínez, L.; Fernández-Cuenca, F.; Pachón, J.; Cisneros, J. M.; Garnacho-Montero, J.; Vila, J.; Rodríguez-Baño, J.; Pascual, A.; Bou, G.

    2016-01-01

    Acinetobacter baumannii is a successful nosocomial pathogen due to its ability to persist in hospital environments by acquiring mobile elements such as transposons, plasmids, and phages. In this study, we compared two genomes of A. baumannii clinical strains isolated in 2000 (ST-2_clon_2000) and 2010 (ST-2_clon_2010) from GenBank project PRJNA308422. PMID:27795287

  6. Complete Genome Sequence of the Clinical Strain Acinetobacter baumannii R2090 Carrying the Chromosomally Encoded Metallo-β-Lactamase Gene blaNDM-1

    PubMed Central

    Krahn, Thomas; Wibberg, Daniel; Maus, Irena; Winkler, Anika; Nordmann, Patrice; Pühler, Alfred; Poirel, Laurent

    2015-01-01

    Acinetobacter baumannii is an emerging human pathogen causing nosocomial and community-acquired infections. Here, we present the complete genome sequence of the clinical A. baumannii strain R2090 carrying the metallo-β-lactamase gene blaNDM-1 in its chromosome within the transposon Tn125. PMID:26358593

  7. Draft Genome Sequence of Klebsiella pneumoniae Carbapenemase-Producing Acinetobacter baumannii Strain M3AC9-7, Isolated from Puerto Rico

    PubMed Central

    Martínez, Teresa; Ropelewski, Alexander J.; González-Mendez, Ricardo; Vázquez, Guillermo J.

    2015-01-01

    We report the draft genome of a multidrug resistant, Klebsiella pneumoniae carbapenemase (KPC)-producing Acinetobacter baumannii strain M3AC9-7 that belongs to the novel sequence type, ST250. The draft genome consists of a total length of 4.09 Mbp and a G+C content of 38.95%. PMID:25858845

  8. Virulence-related traits of epidemic Acinetobacter baumannii strains belonging to the international clonal lineages I-III and to the emerging genotypes ST25 and ST78

    PubMed Central

    2013-01-01

    Background Acinetobacter baumannii is responsible for large epidemics in hospitals, where it can persist for long time on abiotic surfaces. This study investigated some virulence-related traits of epidemic A. baumannii strains assigned to distinct MLST genotypes, including those corresponding to the international clones I-III as well as emerging genotypes responsible for recent epidemics. Methods Genotyping of bacteria was performed by PFGE analysis and MLST according to the Pasteur’s scheme. Biofilm formation on polystyrene plates was assessed by crystal violet staining; resistance to desiccation was evaluated on glass cover-slips when kept at room-temperature and 31% relative humidity; adherence to and invasion of A549 human alveolar epithelial cells were determined by the analysis of viable bacteria associated with or internalized by A549 human alveolar epithelial cells; Galleria mellonella killing assays were used to analyze the virulence of A. baumannii in vivo. Results The ability to form biofilm was significantly higher for A. baumannnii strains assigned to ST2 (international clone II), ST25 and ST78 compared to other STs. All A. baumannii strains survived on dry surfaces for over 16 days, and strains assigned to ST1 (international clone I) and ST78 survived for up to 89 and 96 days, respectively. Adherence to A549 pneumocytes was higher for strains assigned to ST2, ST25 and ST78 than other genotypes; a positive correlation exists between adherence and biofilm formation. Strains assigned to ST78 also showed significantly higher ability to invade A549 cells. No significant differences in the killing of G. mellonella worms were found among strains. Conclusions Elevated resistance to desiccation, high biofilm-forming capacity on abiotic surfaces and adherence to A549 cells might have favoured the spread and persistence in the hospital environment of A. baumannii strains assigned to the international clones I and II and to the emerging genotypes ST25 and ST78

  9. Exceptional desiccation tolerance of Acinetobacter radioresistens.

    PubMed

    Jawad, A; Snelling, A M; Heritage, J; Hawkey, P M

    1998-07-01

    The taxonomy of the genus Acinetobacter, which includes several important nosocomial pathogens, has been confused due to a lack of discriminatory phenotypic characteristics for identification. Molecular methods such as amplified ribosomal DNA restriction analysis (ARDRA) now enable the accurate identification of species. Ten clinical isolates of Acinetobacter radioresistens had genospecies confirmed by ARDRA but the APJ 20NE system, commonly used in clinical microbiology laboratories, mis-identified them as Acinetobacter lwoffii. Desiccation resistance of Acinetobacter spp. is an important attribute for their survival in the clinical environment. We investigated the ability of A. radioresistens to survive desiccation using an established glass surface model and compared the results to A. lwoffii and Acinetobacter baumannii. The 10 strains of A. radioresistens were extremely resistant to desiccation and survived for an average of 157 days at 31% relative humidity (RH). In contrast, two strains of A. lwoffii and three strains of A. baumannii survived for an average of three and 20 days respectively, at 31% RH, which was used as an approximation to climatic conditions in UK hospitals. A. radioresistens is thus well adapted for survival in the hospital environment and carriage on human skin and yet it is reported less frequently than A. lwoffii amongst clinical isolates. Cases of A. radioresistens infection may be under-reported due to mis-identification as A. lwoffii and further studies that use molecular identification methods are required to elucidate the role of A. radioresistens in human disease.

  10. Enrichment of Acinetobacter spp. from food samples.

    PubMed

    Carvalheira, Ana; Ferreira, Vânia; Silva, Joana; Teixeira, Paula

    2016-05-01

    Relatively little is known about the role of foods in the chain of transmission of acinetobacters and the occurrence of different Acinetobacter spp. in foods. Currently, there is no standard procedure to recover acinetobacters from food in order to gain insight into the food-related ecology and epidemiology of acinetobacters. This study aimed to assess whether enrichment in Dijkshoorn enrichment medium followed by plating in CHROMagar™ Acinetobacter medium is a useful method for the isolation of Acinetobacter spp. from foods. Recovery of six Acinetobacter species from food spiked with these organisms was compared for two selective enrichment media (Baumann's enrichment and Dijkshoorn's enrichment). Significantly (p < 0.01) higher cell counts were obtained in Dijkshoorn's enrichment. Next, the Dijkshoorn's enrichment followed by direct plating on CHROMagar™ Acinetobacter was applied to detect Acinetobacter spp. in different foods. Fourteen different presumptive acinetobacters were recovered and assumed to represent nine different strains on the basis of REP-PCR typing. Eight of these strains were identified by rpoB gene analysis as belonging to the species Acinetobacter johnsonii, Acinetobacter calcoaceticus, Acinetobacter guillouiae and Acinetobacter gandensis. It was not possible to identify the species level of one strain which may suggests that it represents a distinct species.

  11. Imported PER-1 producing Pseudomonas aeruginosa, PER-1 producing Acinetobacter baumanii and VIM-2-producing Pseudomonas aeruginosa strains in Hungary

    PubMed Central

    Szabó, Dora; Szentandrássy, Julia; Juhász, Zsuzsa; Katona, Katalin; Nagy, Károly; Rókusz, László

    2008-01-01

    Introduction Pseudomonas aeruginosa and Acinetobacter baumanii are important nosocomial pathogens with wide intrinsic resistance. However, due to the dissemination of the acquired resistance mechanisms, such as extended-spectrum beta-lactamase (ESBL) and metallo beta-lactamase (MBL) production, multidrug resistant strains have been isolated more often. Case presentation We report a case of a Hungarian tourist, who was initially hospitalized in Egypt and later transferred to Hungary. On the day of admission PER-1-producing P. aeruginosa, PER-1 producing A. baumannii, SHV-5-producing Klebsiella pneumoniae and VIM-2-producing P. aeruginosa isolates were subcultured from the patient's samples in Hungary. Comparing the pulsed-field gel electrophoresis (PFGE) patterns of the P. aeruginosa strains from the patient to the P. aeruginosa strains occurring in this hospital, we can state that the PER-1-producing P. aeruginosa and VIM-2-producing P. aeruginosa had external origin. Conclusion This is the first report of PER-1-producing P. aeruginosa,and PER-1-producing A. baumanii strains in Hungary. This case highlights the importance of spreading of the beta-lactamase-mediated resistance mechanisms between countries and continents, showing the importance of careful screening and the isolation of patients arriving from a different country. PMID:18513394

  12. Serum resistance, gallium nitrate tolerance and extrapulmonary dissemination are linked to heme consumption in a bacteremic strain of Acinetobacter baumannii.

    PubMed

    de Léséleuc, Louis; Harris, Greg; KuoLee, Rhonda; Xu, H Howard; Chen, Wangxue

    2014-05-01

    Bacteremia caused by Acinetobacter baumannii is a highly lethal complication of hospital-acquired pneumonia. In the present study, we investigated the serum resistance, gallium nitrate tolerance and heme consumption of A. baumannii strain LAC-4 which was recently reported to display high virulence in a mouse pneumonia model with extrapulmonary dissemination leading to fatal bacteremia. This strain showed enhanced growth in mouse and fetal bovine serum that was independent of complement and was not observed with regular growth media. The LAC-4 strain was found to possess a high tolerance to gallium nitrate (GaN), whereas serum synergized with GaN in inhibiting A. baumannii strain ATCC 17978. We found that LAC-4 contains a heme oxygenase gene and expresses a highly efficient heme consumption system. This system can be fully blocked in vitro and in vivo by gallium protoporphyrin IX (GaPPIX). Inhibition of heme consumption by GaPPIX completely abrogated the growth advantage of LAC-4 in serum as well as its tolerance to GaN. More importantly, GaPPIX treatment of mice intranasally infected with LAC-4 prevented extrapulmonary dissemination and death. Thus, we propose that heme provides an additional source of iron for LAC-4 to bypass iron restriction caused by serum transferrin, lactoferrin or free gallium salts. Heme consumption systems in A. baumannii may constitute major virulence factors for lethal bacteremic isolates. Copyright © 2014 Crown Copyright and Elsevier Inc. Published by Elsevier GmbH.. All rights reserved.

  13. Genotypic and Antimicrobial Susceptibility of Carbapenem-resistant Acinetobacter baumannii: Analysis of ISAba Elements and blaOXA-23-like Genes Including a New Variant

    PubMed Central

    Bahador, Abbas; Raoofian, Reza; Pourakbari, Babak; Taheri, Mohammad; Hashemizadeh, Zahra; Hashemi, Farhad B.

    2015-01-01

    Carbapenem-resistant Acinetobacter baumannii (CR-AB) causes serious nosocomial infections, especially in ICU wards of hospitals, worldwide. Expression of blaOXA genes is the chief mechanism of conferring carbapenem resistance among CR-AB. Although some blaOXA genes have been studied among CR-AB isolates from Iran, their blaOXA-23-like genes have not been investigated. We used a multiplex-PCR to detect Ambler class A, B, and D carbapenemases of 85 isolates, and determined that 34 harbored blaOXA-23-like genes. Amplified fragment length polymorphism (AFLP) genotyping, followed by DNA sequencing of blaOXA-23-like amplicons of CR-AB from each AFLP group was used to characterize their blaOXA-23-like genes. We also assessed the antimicrobial susceptibility pattern of CR-AB isolates, and tested whether they harbored insertion sequences ISAba1 and ISAba4. Sequence comparison with reference strain A. baumannii (NCTC12156) revealed five types of mutations in blaOXA-23-like genes; including one novel variant and four mutants that were already reported from China and the USA. All of the blaOXA-23-like genes mutations were associated with increased minimum inhibitory concentrations (MICs) against imipenem. ISAba1 and ISAba4 sequences were detected upstream of blaOXA-23 genes in 19 and 7% of isolates, respectively. The isolation of CR-AB with new blaOXA-23 mutations including some that have been reported from the USA and China highlights CR-AB pervasive distribution, which underscores the importance of concerted national and global efforts to control the spread of CR-AB isolates worldwide. PMID:26617588

  14. Genotypic and Antimicrobial Susceptibility of Carbapenem-resistant Acinetobacter baumannii: Analysis of is Aba Elements and bla OXA-23-like Genes Including a New Variant.

    PubMed

    Bahador, Abbas; Raoofian, Reza; Pourakbari, Babak; Taheri, Mohammad; Hashemizadeh, Zahra; Hashemi, Farhad B

    2015-01-01

    Carbapenem-resistant Acinetobacter baumannii (CR-AB) causes serious nosocomial infections, especially in ICU wards of hospitals, worldwide. Expression of bla OXA genes is the chief mechanism of conferring carbapenem resistance among CR-AB. Although some bla OXA genes have been studied among CR-AB isolates from Iran, their bla OXA-23-like genes have not been investigated. We used a multiplex-PCR to detect Ambler class A, B, and D carbapenemases of 85 isolates, and determined that 34 harbored bla OXA-23-like genes. Amplified fragment length polymorphism (AFLP) genotyping, followed by DNA sequencing of bla OXA-23-like amplicons of CR-AB from each AFLP group was used to characterize their bla OXA-23-like genes. We also assessed the antimicrobial susceptibility pattern of CR-AB isolates, and tested whether they harbored insertion sequences ISAba1 and ISAba4. Sequence comparison with reference strain A. baumannii (NCTC12156) revealed five types of mutations in bla OXA-23-like genes; including one novel variant and four mutants that were already reported from China and the USA. All of the bla OXA-23-like genes mutations were associated with increased minimum inhibitory concentrations (MICs) against imipenem. ISAba1 and ISAba4 sequences were detected upstream of bla OXA-23 genes in 19 and 7% of isolates, respectively. The isolation of CR-AB with new bla OXA-23 mutations including some that have been reported from the USA and China highlights CR-AB pervasive distribution, which underscores the importance of concerted national and global efforts to control the spread of CR-AB isolates worldwide.

  15. [Characterization and determination of antibiotic resistance profiles of a single clone Acinetobacter baumannii strains isolated from blood cultures].

    PubMed

    Karagöz, Alper; Baran, Irmak; Aksu, Neriman; Acar, Sümeyra; Durmaz, Rıza

    2014-10-01

    Acinetobacter baumannii which is a significant cause of nosocomial infections, increases the rate of morbidity and mortality in health care settings especially in intensive care units (ICUs). The aim of this study was to determine the antibiotic resistance profiles of A.baumannii strains isolated from blood cultures of inpatients from different ICUs, wards and hospital environment and evaluate their clonal relationships and epidemiologic features. A total of 54 A.baumannii strains (47 from the blood cultures and 7 from the hospital environment), identified between 01 January 2012-28 December 2012 at the Clinical Microbiology Laboratory of Ankara Numune Training and Research Hospital, Turkey, were included in the study. Identification of A.baumannii isolates and their antimicrobial [sulbactam-ampicillin (SAM), piperacillin (PIP), piperacillin-tazobactam (TZP), ceftazidime (CFZ), cefoperazone-sulbactam (SCF), cefepime (CEF), imipenem (IMP), meropenem (MER), amikacin (AMK), gentamicin (GEN), netilmicin (NT), ciprofloxacin (CIP), levofloxacin (LVF), tetracycline (TET), tigecycline (TG), colistin (COL), trimethoprim-sulfamethoxazole (SXT)] susceptibility testing were performed by Vitek 2 (bioMérieux, France) system. The clonal relationship between the A.baumannii isolates was analysed by pulsed-field gel electrophoresis (PFGE). In our study colistin, tigecycline and netilmicin were found to be the most effective agents against A.baumannii isolates. All of the clinical isolates (n= 47) were found susceptible to COL, however all were resistant to SAM, PIP, TZP, CEF, IPM, CFZ, MER and CIP. While 1.85%, 14.8%, 14.8%, 16.6%, 59.2% and 22.2% of the isolates were susceptible to SCF, AMK, NT, GEN, TG and SXT, respectively; 1.85%, 1.85%, 9.2%, 16.6%, 38.8% and 27.7% of the isolates were intermediate to SCF, TET, AMK, NT, LVF and TG, respectively. Similarly, all of the environmental A.baumannii isolates (n= 7) were resistant to SAM, PIP, TZP, CFZ, CEF, IPM, MER and CIP, and all

  16. Diversity of Acinetobacter baumannii strains isolated in humans, companion animals, and the environment in Reunion Island: an exploratory study.

    PubMed

    Pailhoriès, Hélène; Belmonte, Olivier; Kempf, Marie; Lemarié, Carole; Cuziat, Julien; Quinqueneau, Catherine; Ramont, Catherine; Joly-Guillou, Marie-Laure; Eveillard, Matthieu

    2015-08-01

    Acinetobacter baumannii can be responsible for community-acquired infections in tropical climates like that of Reunion Island. The epidemiology of these community-acquired A. baumannii infections is not well understood. The aim of this study was to characterize A. baumannii strains isolated from patients at the time of admission to the university hospital of Saint-Denis, from environmental samples, and from pets. In this exploratory study, samples were collected by swabbing the rectum and mouth. A. baumannii isolates from positive samples were identified by VITEK 2 system, blaOXA-51-like gene PCR, and partial sequencing of the rpoB gene. Antimicrobial susceptibility testing was then performed. Strains were further analysed by multilocus sequence typing and pulsed-field gel electrophoresis. A high prevalence of A. baumannii carriage was found in pets (8.5%). Only one A. baumannii isolate was resistant to carbapenems (isolated from a patient). A wide variety of A. baumannii, assigned to different sequence types, were isolated from pets, humans, and the environment. This study shows that A. baumannii strains are present outside the hospital setting in Reunion Island and show great diversity. Further studies are needed to explore these extra-hospital reservoirs of A. baumannii in Reunion Island in greater detail and to determine their possible means of dissemination. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Prevalence of carbapenemase-encoding genes including New Delhi metallo-β-lactamase in Acinetobacter species, Algeria.

    PubMed

    Mesli, Esma; Berrazeg, Meryem; Drissi, Mourad; Bekkhoucha, Souad Naïma; Rolain, Jean-Marc

    2013-09-01

    Nosocomial infections caused by carbapenem-resistant Acinetobacter spp are a global health problem. The aim of this study was to investigate the molecular epidemiology and the genetic support of carbapenem resistance in Acinetobacter spp clinical isolates recovered from three different hospitals in western Algeria from 2008 to 2012. A total of 113 Acinetobacter spp isolates were identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. Antimicrobial susceptibility testing was carried out, and minimum inhibitory concentrations (MICs) were determined by the dilution method on Mueller-Hinton agar for β-lactams, aminoglycosides, fluoroquinolones, and colistin. The characterization of β-lactamases was investigated by phenotypic tests for the detection of metallo-β-lactamases and oxacillinases. Resistance genes were screened for by quantitative PCR and sequenced when positive. Among the 113 isolates, 80 (70.8%) were found to be resistant to imipenem with MICs ranging from 64 to 512μg/ml. The blaOXA-23-like gene was detected in 50% (40/80) of the isolates and the blaOXA-24-like gene was detected in 21.2% (17/80) of the isolates. In addition, the metallo-β-lactamase blaNDM-1-like was detected in five isolates (6.2%). This study represents the first description of autochthonous Acinetobacter spp producing metallo-β-lactamase blaNDM-1-like and oxacillinases blaOXA-23-like and blaOXA-24-like in western Algeria. Copyright © 2013 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  18. Location of the fracture faces within the cell envelope of Acinetobacter species strain MJT-F5-5.

    PubMed

    Sleytr, U B; Thornley, M J; Glauert, A M

    1974-05-01

    The cell wall of the gram-negative bacterium Acinetobacter species strain MJT/F5/5 shows in thin section an external "additional" layer, an outer membrane, an intermediate layer, and a dense layer. Negatively stained preparations showed that the additional layer is composed of hexagonally arranged subunits. In glycerol-treated preparations, freeze-etching revealed that the cell walls consist of four layers, with the main plane of fracture between layers cw 2 and cw 3. The surface of [Formula: see text] 2 consisted of densely packed particles, whereas [Formula: see text] 3 appeared to be fibrillar. In cell envelopes treated with lysozyme by various methods, the removal of the dense layer has detached the outer membrane and additional layer from the underlying layers, as shown in thin sections. When freeze-etched in the absence of glycerol, these detached outer membranes with additional layers fractured to reveal both the faces [Formula: see text] 2 and [Formula: see text] 3 with their characteristic surface structures, and, in addition, both the external and internal etched surfaces were revealed. This experiment provided conclusive evidence that the main fracture plane in the cell wall lies within the interior of the outer membrane. This and other evidence showed that the corresponding layers in thin sections and freeze-etched preparations are: the additional layer, cw 1; the outer membrane, cw (2 + 3); and the intermediate and dense layers together from cw 4. Because of similarities in structure between this Acinetobacter and other gram-negative bacteria, it seemed probable that the interior of the outer membrane is the plane most liable to fracture in the cell walls of most gram-negative bacteria.

  19. AB5075, a Highly Virulent Isolate of Acinetobacter baumannii, as a Model Strain for the Evaluation of Pathogenesis and Antimicrobial Treatments

    PubMed Central

    Jacobs, Anna C.; Thompson, Mitchell G.; Black, Chad C.; Kessler, Jennifer L.; Clark, Lily P.; McQueary, Christin N.; Gancz, Hanan Y.; Corey, Brendan W.; Moon, Jay K.; Si, Yuanzheng; Owen, Matthew T.; Hallock, Justin D.; Kwak, Yoon I.; Summers, Amy; Li, Charles Z.; Rasko, David A.; Penwell, William F.; Honnold, Cary L.; Wise, Matthew C.; Waterman, Paige E.; Lesho, Emil P.; Stewart, Rena L.; Actis, Luis A.; Palys, Thomas J.; Craft, David W.

    2014-01-01

    ABSTRACT Acinetobacter baumannii is recognized as an emerging bacterial pathogen because of traits such as prolonged survival in a desiccated state, effective nosocomial transmission, and an inherent ability to acquire antibiotic resistance genes. A pressing need in the field of A. baumannii research is a suitable model strain that is representative of current clinical isolates, is highly virulent in established animal models, and can be genetically manipulated. To identify a suitable strain, a genetically diverse set of recent U.S. military clinical isolates was assessed. Pulsed-field gel electrophoresis and multiplex PCR determined the genetic diversity of 33 A. baumannii isolates. Subsequently, five representative isolates were tested in murine pulmonary and Galleria mellonella models of infection. Infections with one strain, AB5075, were considerably more severe in both animal models than those with other isolates, as there was a significant decrease in survival rates. AB5075 also caused osteomyelitis in a rat open fracture model, while another isolate did not. Additionally, a Tn5 transposon library was successfully generated in AB5075, and the insertion of exogenous genes into the AB5075 chromosome via Tn7 was completed, suggesting that this isolate may be genetically amenable for research purposes. Finally, proof-of-concept experiments with the antibiotic rifampin showed that this strain can be used in animal models to assess therapies under numerous parameters, including survival rates and lung bacterial burden. We propose that AB5075 can serve as a model strain for A. baumannii pathogenesis due to its relatively recent isolation, multidrug resistance, reproducible virulence in animal models, and genetic tractability. PMID:24865555

  20. Genome Sequence of a Clinical Strain of Acinetobacter baumannii Belonging to the ST79/PFGE-HUI-1 Clone Lacking the AdeABC (Resistance-Nodulation-Cell Division-Type) Efflux Pump

    PubMed Central

    López, M.; Álvarez-Fraga, L.; Gato, E.; Blasco, L.; Poza, M.; Fernández-García, L.; Bou, G.

    2016-01-01

    Increased expression of chromosomal genes for resistance-nodulation-cell division-type efflux systems plays a major role in the multidrug resistance of Acinetobacter baumannii. Little is known about the genetic characteristics of clinical strains of Acinetobacter baumannii lacking the AdeABC pump. In this study, we sequenced the genome of clinical strain Ab421 GEIH-2010 (belonging to clone ST79/PFGE-HUI-1 from the GEIH-REIPI Ab. 2010 project) which lacks this efflux pump. PMID:27609928

  1. Genome Sequence of a Clinical Strain of Acinetobacter baumannii Belonging to the ST79/PFGE-HUI-1 Clone Lacking the AdeABC (Resistance-Nodulation-Cell Division-Type) Efflux Pump.

    PubMed

    López, M; Álvarez-Fraga, L; Gato, E; Blasco, L; Poza, M; Fernández-García, L; Bou, G; Tomás, M

    2016-09-08

    Increased expression of chromosomal genes for resistance-nodulation-cell division-type efflux systems plays a major role in the multidrug resistance of Acinetobacter baumannii Little is known about the genetic characteristics of clinical strains of Acinetobacter baumannii lacking the AdeABC pump. In this study, we sequenced the genome of clinical strain Ab421 GEIH-2010 (belonging to clone ST79/PFGE-HUI-1 from the GEIH-REIPI Ab. 2010 project) which lacks this efflux pump.

  2. Antimicrobial activity of novel 4H-4-oxoquinolizine compounds against extensively drug-resistant Acinetobacter baumannii strains.

    PubMed

    Na, Seok Hyeon; Jeon, Hyejin; Kim, Yoo Jeong; Kwon, Hyo Il; Selasi, Gati Noble; Nicholas, Asiimwe; Yun, Chang-Soo; Lee, Sang Ho; Lee, Je Chul

    2017-01-01

    The aim of this study was to screen lead compounds exhibiting potent in vitro antimicrobial activity against multidrug-resistant (MDR) Acinetobacter baumannii strains from a library of chemical compounds. In a high-throughput screening analysis of 7520 compounds representative of 340,000 small molecules, two 4H-4-oxoquinolizine compounds were the most active against A. baumannii ATCC 17978. Subsequent selection and analysis of 70 4H-4-oxoquinolizine compounds revealed that the top 7 compounds were extremely active against extensively drug-resistant (XDR) A. baumannii isolates. These compounds commonly carried a 1-cyclopropyl-7-fluoro-4-oxo-4H-quinolizine-3-carboxylic acid core structure but had different C-8 and/or C-9 moieties. Minimum inhibitory concentrations (MICs) of the seven compounds against fluoroquinolone-resistant A. baumannii isolates were found to be in the range of 0.02-1.70 µg/mL regardless of the mutation types in the quinolone resistance-determining region (QRDR) of GyrA and ParC. Cytotoxicity of the seven compounds was observed in HeLa and U937 cells at a concentration of 50 µg/mL, which was >32.5- to 119-fold higher than the MIC90 for A. baumannii isolates. In conclusion, novel 4H-4-oxoquinolizine compounds represent a promising scaffold on which to develop antimicrobial agents against drug-resistant A. baumannii strains.

  3. Comparison of a Repetitive Extragenic Palindromic Sequence-Based PCR Method and Clinical and Microbiological Methods for Determining Strain Sources in Cases of Nosocomial Acinetobacter baumannii Bacteremia

    PubMed Central

    Martín-Lozano, David; Cisneros, José Miguel; Becerril, Berta; Cuberos, Lucila; Prados, Trinidad; Ortíz-Leyba, Carlos; Cañas, Elías; Pachón, Jerónimo

    2002-01-01

    Using a repetitive extragenic palindromic PCR (REP-PCR), we genotypically characterized strains causing nosocomial Acinetobacter baumannii infections and analyzed the source of bacteremia in 67 patients from an institution in which infections by this bacterium were endemic. Six different genotypes were found, including 21, 27, 3, 9, 3, and 4 strains. The probable source of bacteremia, according to clinical and/or microbiological criteria, was known in 42 patients (63%): respiratory tract (n = 19), surgical sites (n = 12), intravascular catheters (n = 5), burns (n = 3), and urinary tract (n = 3). The definite source of bacteremia, according to REP-PCR, could be established in 30 (71%) out of the 42 patients with strains from blood and other sites; in these cases clinical and microbiological criteria for the source of bacteremia were thus confirmed. In the remaining 12 patients (29%) the probable source was refuted by the REP-PCR method. The definite sources of bacteremia according to genotype were as follows: respiratory tract in 13 patients (31%), surgical sites in 8 (19%), intravascular catheters in 4 (9%), burns in 3 (7%), and urinary tract in 2 (5%). A comparison of strains from blood cultures and other sites with regard to their REP-PCR and antimicrobial resistance profiles was also made. Taking the REP-PCR as the “gold standard,” the positive predictive value of antibiotype was 77% and the negative predictive value was 42%. In summary, the utility of the diagnosis of the source of nosocomial A. baumannii bacteremia using clinical and/or microbiological criteria, including antibiotyping, is limited, as demonstrated by REP-PCR. PMID:12454154

  4. Validation of use of whole-cell repetitive extragenic palindromic sequence-based PCR (REP-PCR) for typing strains belonging to the Acinetobacter calcoaceticus-Acinetobacter baumannii complex and application of the method to the investigation of a hospital outbreak.

    PubMed Central

    Snelling, A M; Gerner-Smidt, P; Hawkey, P M; Heritage, J; Parnell, P; Porter, C; Bodenham, A R; Inglis, T

    1996-01-01

    Acinetobacter spp. are being reported with increasing frequency as causes of nosocomial infection. In order to identify reservoirs of infection as quickly as possible, a rapid typing method that can differentiate epidemic strains from environmental and nonepidemic strains is needed. In 1993, a cluster of Acinetobacter baumannii isolates from five patients in the adult intensive therapy unit of our tertiary-care teaching hospital led us to develop and optimize a rapid repetitive extragenic palindromic sequence-based PCR (REP-PCR) typing protocol for members of the Acinetobacter calcoaceticus-A. baumannii complex that uses boiled colonies and consensus primers aimed at repetitive extragenic palindromic sequences. Four of the five patient isolates gave the same REP-PCR typing pattern as isolates of A. baumannii obtained from the temperature probe of a Bennett humidifier; the fifth isolate had a unique profile. Disinfection of the probe with 70% ethanol, as recommended by the manufacturer, proved ineffective, as A. baumannii with the same REP-PCR pattern was isolated from it 10 days after cleaning, necessitating a change in our decontamination procedure. Results obtained with REP-PCR were subsequently confirmed by ribotyping. To evaluate the discriminatory power (D) of REP-PCR for typing members of the A. calcoaceticus-A. baumannii complex, compared with that of ribotyping, we have applied both methods to a collection of 85 strains that included representatives of six DNA groups within the complex. Ribotyping using EcoRI digests yielded 53 patterns (D = 0.98), whereas 68 different REP-PCR patterns were observed (D = 0.99). By computer-assisted analysis of gel images, 74 patterns were observed with REP-PCR (D = 1.0). Overall, REP-PCR typing proved to be slightly more discriminatory than ribotyping. Our results indicate that REP-PCR typing used boiled colonies is a simple, rapid, and effective means of typing members of the A. calcoaceticus-A. baumannii complex. PMID

  5. Acinetobacter baumannii: emergence of four strains with novel bla(OXA-51-like) genes in patients with diabetes mellitus.

    PubMed

    Alsultan, A A; Hamouda, A; Evans, B A; Amyes, S G B

    2009-06-01

    Diabetic patients are 10 times more likely to develop Acinetobacter baumannii infections than the rest of the population. Carbapenems are considered one of the very few antibiotics left to treat infections caused by this organism. the aim of this work was to characterise A. baumannii strains isolated from diabetic patients and to investigate whether there is a relationship between certain strains and low-level-carbapenem resistance. Clinical samples were collected from diabetic patients in hospitals throughout Saudi Arabia from December 2006 to April 2007. API 20 Ne, polymorphisms in the 16S-23S-rRNA intergenic region and the presence of a bla( OXA-51-like )gene were all used for identification. Susceptibility to antimicrobials was determined using agar dilution and disk diffusion methods. pulsed-field gel electrophoresis (pfGe) coupled with sequence analysis of the bla(OXA-51-like )genes were used for strain characterization. Polymerase chain reaction (pCR) and multiplex pCR were used to screen for the presence and location of ISAba1 elements and bla(OXA-23-like), bla(OXA-40-like), and bla(OXA-58-like )genes respectively. Twenty isolates were identified as A. baumannii and were all highly resistant to 38% of the antibiotics tested and the majority of isolates were also resistant to 50% of the remaining antibiotics. four strains had low-level meropenem resistance (MIC 4-8 mg/l). All isolates were sensitive to imipenem and colistin. Nine strains possessed four novel bla( OXA-51-like )genes encoding beta-lactamases designated OXA-90, OXA-130, OXA-131 and OXA-132, and four strains contained bla(OXA-131 )with ISAba1 upstream of the gene structure. PFGE showed five separate clusters of OXA-51-like enzymes and the dissemination of strains carrying the four novel enzymes was clonal. this study showed that new strains of A. baumannii characterised by their new bla(OXA-51-like )gene have emerged. No genes encoding OXA-23-like, OXA-40-like, or OXA-58-like beta

  6. Identification and Characterization of a Novel Competence Gene, comC, Required for DNA Binding and Uptake in Acinetobacter sp. Strain BD413

    PubMed Central

    Link, Caroline; Eickernjäger, Sandra; Porstendörfer, Dirk; Averhoff, Beate

    1998-01-01

    A gene (comC) essential for natural transformation was identified in Acinetobacter sp. strain BD413. ComC has a typical leader sequence and is similar to different type IV pilus assembly factors. A comC mutant (T308) is not able to bind or take up DNA but exhibits a piliation phenotype indistinguishable from the transformation wild type as revealed by electron microscopy. PMID:9515934

  7. Molecular Characterization of the Gene Encoding a New AmpC β-Lactamase in a Clinical Strain of Acinetobacter Genomic Species 3

    PubMed Central

    Beceiro, Alejandro; Dominguez, Lourdes; Ribera, Anna; Vila, Jordi; Molina, Francisca; Villanueva, Rosa; Eiros, Jose Maria; Bou, German

    2004-01-01

    A presumptive chromosomal cephalosporinase (pI, 9.0) from a clinical strain of Acinetobacter genomic species 3 (AG3) is reported. The nucleotide sequence of this β-lactamase shows for the first time the gene encoding an AmpC enzyme in AG3. In addition, the biochemical properties of the novel AG3 AmpC β-lactamase are reported PMID:15047547

  8. [Shall we report the carbapenem resistance in Pseudomonas aeruginosa and Acinetobacter baumannii strains detected by BD Phoenix system?].

    PubMed

    Oğünç, Dilara; Ongüt, Gözde; Ozen, Nevgün Sepin; Baysan, Betil Ozhak; Günseren, Filiz; Dağlar, Duygu; Demirbakan, Hadiye; Gültekin, Meral

    2010-04-01

    Imipenem and meropenem are broad spectrum antimicrobial agents that are especially useful in the treatment of nosocomially acquired Pseudomonas aeruginosa and Acinetobacter spp. infections. Previous reports have noted that susceptibility tests could show false resistance to imipenem. For this reason, Centers for Disease Control and Prevention has recommended that all carbapenem resistant or intermediate resistant isolates should be tested with an additional method to verify the results. This study was aimed to evaluate the imipenem and meropenem susceptibilities by disk diffusion, E-test and broth microdilution in P. aeruginosa and Acinetobacter baumannii strains found to be resistant or intermediate to imipenem-meropenem by BD Phoenix automated susceptibility testing system. Between January 2006-January 2007, 85 non-duplicate isolates of A. baumannii and 51 non-duplicate isolates of P. aeruginosa which were determined as resistant or intermediate resistant to imipenem and/or meropenem by BD Phoenix automated identification and susceptibility system (Becton Dickinson, Sparks, MD, USA) were collected in Akdeniz University Hospital Central Laboratory. All strains were tested by E-test (AB Biodisk, Sweden), disk diffusion and reference broth microdilution (BMD) method following CLSI recommendations. All 51 isolates of P. aeruginosa determined as imipenem and/or meropenem resistant or intermediate resistant by BD Phoenix, were found to be imipenem and/or meropenem resistant or intermediate resistant by the reference BMD method. Minor error rates were same for all testing systems (1.9%) except for the meropenem results of BD Phoenix system (5.9%). No major errors were produced by any system. For A. baumannii, only one very major error was detected for meropenem by BD Phoenix system. Number of minor errors determined for meropenem by all testing systems compared to the reference test, ranged from 2 (2.4%) to 3 (3.5%). It was concluded that carbapenem susceptibility test

  9. Insertions or Deletions (Indels) in the rrn 16S-23S rRNA Gene Internal Transcribed Spacer Region (ITS) Compromise the Typing and Identification of Strains within the Acinetobacter calcoaceticus-baumannii (Acb) Complex and Closely Related Members

    PubMed Central

    Maslunka, Christopher; Gifford, Bianca; Tucci, Joseph; Gürtler, Volker; Seviour, Robert J.

    2014-01-01

    To determine whether ITS sequences in the rrn operon are suitable for identifying individual Acinetobacter Acb complex members, we analysed length and sequence differences between multiple ITS copies within the genomes of individual strains. Length differences in ITS reported previously between A. nosocomialis BCRC15417T (615 bp) and other strains (607 bp) can be explained by presence of an insertion (indel 13i/1) in the longer ITS variant. The same Indel 13i/1 was also found in ITS sequences of ten strains of A. calcoaceticus, all 639 bp long, and the 628 bp ITS of Acinetobacter strain BENAB127. Four additional indels (13i/2–13i/5) were detected in Acinetobacter strain c/t13TU 10090 ITS length variants (608, 609, 620, 621 and 630 bp). These ITS variants appear to have resulted from horizontal gene transfer involving other Acinetobacter species or in some cases unrelated bacteria. Although some ITS copies in strain c/t13TU 10090 are of the same length (620 bp) as those in Acinetobacter strains b/n1&3, A. pittii (10 strains), A. calcoaceticus and A. oleivorans (not currently acknowledged as an Acb member), their individual ITS sequences differ. Thus ITS length by itself can not by itself be used to identify Acb complex strains. A shared indel in ITS copies in two separate Acinetobacter species compromises the specificity of ITS targeted probes, as shown with the Aun-3 probe designed to target the ITS in A. pitti. The presence of indel 13i/5 in the ITS of Acinetobacter strain c/t13TU means it too responded positively to this probe. Thus, neither ITS sequencing nor the currently available ITS targeted probes can distinguish reliably between Acb member species. PMID:25141005

  10. In Vivo Application of Bacteriophage as a Potential Therapeutic Agent To Control OXA-66-Like Carbapenemase-Producing Acinetobacter baumannii Strains Belonging to Sequence Type 357.

    PubMed

    Jeon, Jongsoo; Ryu, Choong-Min; Lee, Jun-Young; Park, Jong-Hwan; Yong, Dongeun; Lee, Kyungwon

    2016-07-15

    The increasing prevalence of carbapenem-resistant Acinetobacter baumannii (CRAB) strains in intensive care units has caused major problems in public health worldwide. Our aim was to determine whether this phage could be used as an alternative therapeutic agent against multidrug-resistant bacterial strains, specifically CRAB clinical isolates, using a mouse model. Ten bacteriophages that caused lysis in CRAB strains, including blaOXA-66-like genes, were isolated. YMC13/01/C62 ABA BP (phage Bϕ-C62), which showed the strongest lysis activity, was chosen for further study by transmission electron microscopy (TEM), host range test, one-step growth and phage adsorption rate, thermal and pH stability, bacteriolytic activity test, genome sequencing and bioinformatics analysis, and therapeutic effect of phage using a mouse intranasal infection model. The phage Bϕ-C62 displayed high stability at various temperatures and pH values and strong cell lysis activity in vitro The phage Bϕ-C62 genome has a double-stranded linear DNA with a length of 44,844 bp, and known virulence genes were not identified in silico. In vivo study showed that all mice treated with phage Bϕ-C62 survived after intranasal bacterial challenge. Bacterial clearance in the lung was observed within 3 days after bacterial challenge, and histologic damage also improved significantly; moreover, no side effects were observed. In our study, the novel A. baumannii phage Bϕ-C62 was characterized and evaluated in vitro, in silico, and in vivo These results, including strong lytic activities and the improvement of survival rates, showed the therapeutic potential of the phage Bϕ-C62 as an antimicrobial agent. This study reports the potential of a novel phage as a therapeutic candidate or nontoxic disinfectant against CRAB clinical isolates in vitro and in vivo. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  11. In Vivo Application of Bacteriophage as a Potential Therapeutic Agent To Control OXA-66-Like Carbapenemase-Producing Acinetobacter baumannii Strains Belonging to Sequence Type 357

    PubMed Central

    Jeon, Jongsoo; Ryu, Choong-Min; Lee, Jun-Young; Park, Jong-Hwan; Lee, Kyungwon

    2016-01-01

    ABSTRACT The increasing prevalence of carbapenem-resistant Acinetobacter baumannii (CRAB) strains in intensive care units has caused major problems in public health worldwide. Our aim was to determine whether this phage could be used as an alternative therapeutic agent against multidrug-resistant bacterial strains, specifically CRAB clinical isolates, using a mouse model. Ten bacteriophages that caused lysis in CRAB strains, including blaOXA-66-like genes, were isolated. YMC13/01/C62 ABA BP (phage Bϕ-C62), which showed the strongest lysis activity, was chosen for further study by transmission electron microscopy (TEM), host range test, one-step growth and phage adsorption rate, thermal and pH stability, bacteriolytic activity test, genome sequencing and bioinformatics analysis, and therapeutic effect of phage using a mouse intranasal infection model. The phage Bϕ-C62 displayed high stability at various temperatures and pH values and strong cell lysis activity in vitro. The phage Bϕ-C62 genome has a double-stranded linear DNA with a length of 44,844 bp, and known virulence genes were not identified in silico. In vivo study showed that all mice treated with phage Bϕ-C62 survived after intranasal bacterial challenge. Bacterial clearance in the lung was observed within 3 days after bacterial challenge, and histologic damage also improved significantly; moreover, no side effects were observed. IMPORTANCE In our study, the novel A. baumannii phage Bϕ-C62 was characterized and evaluated in vitro, in silico, and in vivo. These results, including strong lytic activities and the improvement of survival rates, showed the therapeutic potential of the phage Bϕ-C62 as an antimicrobial agent. This study reports the potential of a novel phage as a therapeutic candidate or nontoxic disinfectant against CRAB clinical isolates in vitro and in vivo. PMID:27208124

  12. Crude oil degradation efficiency of a recombinant Acinetobacter baumannii strain and its survival in crude oil-contaminated soil microcosm.

    PubMed

    Mishra, Sanjeet; Sarma, Priyangshu M; Lal, Banwari

    2004-06-15

    A hydrocarbon degrading Acinetobacter baumannii S30 strain, isolated from crude oil-contaminated soil, was inserted with the lux gene from the luciferase gene cassette luxCDABE. Soil microcosms were designed to study the degradation efficacy for total petroleum hydrocarbon (TPH) of crude oil by lux-tagged A. baumannii S30 pJES. Bioaugmentation of a TPH-contaminated microcosm with A baumannii S30 pJES showed that TPH levels were reduced from 89.3 to 53.9 g/kg soil in 90 days. Biodegradation of TPH by A baumannii S30 pJES was also monitored in shake flask conditions, which showed a reduction of initial TPH levels by over 50% at the end of 120 h. A lux-PCR-based approach along with the standard dilution plating with selective antibiotics was successfully utilized to monitor the survivability of the lux-tagged strain A. baumannii S30 pJES in soil microcosms and stability of the lux insert in the host strain A. baumannii S30. The selective plating technique indicated the population of A. baumannii S30 pJES to be 6.5+/-0.13 x 10(8) CFU/g at day zero (just after bioaugmentation) and 2.09+/-0.08 x 10(8) CFU/g of soil after 90 days of incubation. lux-PCR confirmed the stability of the insert in all the randomly selected colonies of A. baumannii strains from the antibiotic plates. The lux insert was stable after 50 generations in Luria Bertini broth and storage at -70 degrees C as glycerol stocks for over a year. These results revealed that the lux insert was stable and lux-tagged A. baumannii S30 strain could survive in a TPH-contaminated soil microcosm and could degrade TPH in the soil microcosm conditions. It can be used as an effective marker to monitor the survival of augmented strains at a bioremediation site.

  13. Potential Synergy Activity of the Novel Ceragenin, CSA-13, against Carbapenem-Resistant Acinetobacter baumannii Strains Isolated from Bacteremia Patients

    PubMed Central

    Bozkurt-Guzel, Cagla; Savage, Paul B.; Akcali, Alper; Ozbek-Celik, Berna

    2014-01-01

    Carbapenem-resistant Acinetobacter baumannii is an important cause of nosocomial infections, particularly in patients in the intensive care units. As chronic infections are difficult to treat, attempts have been made to discover new antimicrobials. Ceragenins, designed to mimic the activities of antimicrobial peptides, are a new class of antimicrobial agents. In this study, the in vitro activities of CSA-13 either alone or in combination with colistin (sulphate), tobramycin, and ciprofloxacin were investigated using 60 carbapenem-resistant A. baumannii strains isolated from bacteremia patients blood specimens. MICs and MBCs were determined by microbroth dilution technique. Combinations were assessed by using checkerboard technique. The MIC50 values (mg/L) of CSA-13, colistin, tobramycin, and ciprofloxacin were 2, 1, 1.25, and 80, respectively. The MIC90 (mg/L) of CSA-13 and colistin were 8 and 4. The MBCs were equal to or twice greater than those of the MICs. Synergistic interactions were mostly seen with CSA-13-colistin (55%), whereas the least synergistic interactions were observed in the CSA-13-tobramycin (35%) combination. No antagonism was observed. CSA-13 appears to be a good candidate for further investigations in the treatment of A. baumannii infections. However, future studies should be performed to correlate the safety, efficacy, and pharmacokinetic parameters of this molecule. PMID:24804236

  14. Long-Chain Aldehyde Dehydrogenase That Participates in n-Alkane Utilization and Wax Ester Synthesis in Acinetobacter sp. Strain M-1

    PubMed Central

    Ishige, Takeru; Tani, Akio; Sakai, Yasuyoshi; Kato, Nobuo

    2000-01-01

    A long-chain aldehyde dehydrogenase, Ald1, was found in a soluble fraction of Acinetobacter sp. strain M-1 cells grown on n-hexadecane as a sole carbon source. The gene (ald1) was cloned from the chromosomal DNA of the bacterium. The open reading frame of ald1 was 1,512 bp long, corresponding to a protein of 503 amino acid residues (molecular mass, 55,496 Da), and the deduced amino acid sequence showed high similarity to those of various aldehyde dehydrogenases. The ald1 gene was stably expressed in Escherichia coli, and the gene product (recombinant Ald1 [rAld1]) was purified to apparent homogeneity by gel electrophoresis. rAld1 showed enzyme activity toward n-alkanals (C4 to C14), with a preference for longer carbon chains within the tested range; the highest activity was obtained with tetradecanal. The ald1 gene was disrupted by homologous recombination on the Acinetobacter genome. Although the ald1 disruptant (ald1Δ) strain still had the ability to grow on n-hexadecane to some extent, its aldehyde dehydrogenase activity toward n-tetradecanal was reduced to half the level of the wild-type strain. Under nitrogen-limiting conditions, the accumulation of intracellular wax esters in the ald1Δ strain became much lower than that in the wild-type strain. These and other results imply that a soluble long-chain aldehyde dehydrogenase indeed plays important roles both in growth on n-alkane and in wax ester formation in Acinetobacter sp. strain M-1. PMID:10919810

  15. Characterization of a Nosocomial Outbreak Caused by a Multiresistant Acinetobacter baumannii Strain with a Carbapenem-Hydrolyzing Enzyme: High-Level Carbapenem Resistance in A. baumannii Is Not Due Solely to the Presence of β-Lactamases

    PubMed Central

    Bou, Germán; Cerveró, Gonzalo; Domínguez, M. Angeles; Quereda, Carmen; Martínez-Beltrán, Jesús

    2000-01-01

    From February to November 1997, 29 inpatients at Ramón y Cajal Hospital, Madrid, Spain, were determined to be either colonized or infected with imipenem- and meropenem-resistant Acinetobacter baumannii (IMRAB) strains (MICs, 128 to 256 μg/ml). A wide antibiotic multiresistance profile was observed with IMRAB strains. For typing IMRAB isolates, pulsed-field gel electrophoresis was used. For comparative purposes, 30 imipenem- and meropenem-susceptible A. baumannii (IMSAB) strains isolated before, during, and after the outbreak were included in this study. The molecular-typing results showed that the outbreak was caused by a single IMRAB strain (genotype A). By cloning experiments we identified a class D β-lactamase (OXA-24) encoded in the chromosomal DNA of this IMRAB strain which showed carbapenem hydrolysis. Moreover, the outer membrane profile of the IMRAB strain showed a reduction in the expression of two porins at 22 and 33 kDa when compared with genetically related IMSAB isolates. In addition no efflux mechanisms were identified in the IMRAB strains. In summary, we report here the molecular characterization of a nosocomial outbreak caused by one multiresistant A. baumannii epidemic strain that harbors a carbapenem-hydrolyzing enzyme. Although alterations in the penicillin-binding proteins cannot be ruled out, the reduction in the expression of two porins and the presence of this OXA-derived β-lactamase are involved in the carbapenem resistance of the epidemic nosocomial IMRAB strain. PMID:10970374

  16. Extremophilic Acinetobacter strains from high-altitude lakes in Argentinean Puna: remarkable UV-B resistance and efficient DNA damage repair.

    PubMed

    Albarracín, Virginia Helena; Pathak, Gopal P; Douki, Thierry; Cadet, Jean; Borsarelli, Claudio Darío; Gärtner, Wolfgang; Farias, María Eugenia

    2012-06-01

    High-Altitude Andean Lakes (HAAL) of the South American Andes are almost unexplored ecosystems of shallow lakes. The HAAL are recognized by a remarkably high UV exposure, strong changes in temperature and salinity, and a high content of toxic elements, especially arsenic. Being exposed to remarkably extreme conditions, they have been classified as model systems for the study of life on other planets. Particularly, Acinetobacter strains isolated from the HAAL were studied for their survival competence under strong UV-B irradiation. Clinical isolates, Acinetobacter baumannii and Acinetobacter johnsonii, served as reference material. Whereas the reference strains rapidly lost viability under UV-B irradiation, most HAAL-derived strains readily survived this exposure and showed less change in cell number after the treatment. Controls for DNA repair activity, comparing dark repair (DR) or photo repair (PR), gave evidence for the involvement of photolyases in the DNA repair. Comparative measurements by HPLC-mass spectrometry detected the number of photoproducts: bipyrimidine dimers under both PR and DR treatments were more efficiently repaired in the HAAL strains (up to 85 % PR and 38 % DR) than in the controls (31 % PR and zero DR ability). Analysis of cosmid-cloned total genomic DNA from the most effective DNA-photorepair strain (Ver3) yielded a gene (HQ443199) encoding a protein with clear photolyase signatures belonging to class I CPD-photolyases. Despite the relatively low sequence similarity of 41 % between the enzymes from Ver3 and from E. coli (PDB 1DNPA), a model-building approach revealed a high structural homology to the CPD-photolyase of E. coli.

  17. Extremophilic Acinetobacter Strains from High-Altitude Lakes in Argentinean Puna: Remarkable UV-B Resistance and Efficient DNA Damage Repair

    NASA Astrophysics Data System (ADS)

    Albarracín, Virginia Helena; Pathak, Gopal P.; Douki, Thierry; Cadet, Jean; Borsarelli, Claudio Darío; Gärtner, Wolfgang; Farias, María Eugenia

    2012-06-01

    High-Altitude Andean Lakes (HAAL) of the South American Andes are almost unexplored ecosystems of shallow lakes. The HAAL are recognized by a remarkably high UV exposure, strong changes in temperature and salinity, and a high content of toxic elements, especially arsenic. Being exposed to remarkably extreme conditions, they have been classified as model systems for the study of life on other planets. Particularly, Acinetobacter strains isolated from the HAAL were studied for their survival competence under strong UV-B irradiation. Clinical isolates, Acinetobacter baumannii and Acinetobacter johnsonii, served as reference material. Whereas the reference strains rapidly lost viability under UV-B irradiation, most HAAL-derived strains readily survived this exposure and showed less change in cell number after the treatment. Controls for DNA repair activity, comparing dark repair (DR) or photo repair (PR), gave evidence for the involvement of photolyases in the DNA repair. Comparative measurements by HPLC-mass spectrometry detected the number of photoproducts: bipyrimidine dimers under both PR and DR treatments were more efficiently repaired in the HAAL strains (up to 85 % PR and 38 % DR) than in the controls (31 % PR and zero DR ability). Analysis of cosmid-cloned total genomic DNA from the most effective DNA-photorepair strain (Ver3) yielded a gene (HQ443199) encoding a protein with clear photolyase signatures belonging to class I CPD-photolyases. Despite the relatively low sequence similarity of 41 % between the enzymes from Ver3 and from E. coli (PDB 1DNPA), a model-building approach revealed a high structural homology to the CPD-photolyase of E. coli.

  18. Acinetobacter Pneumonia: A Review

    PubMed Central

    Hartzell, Joshua D.; Kim, Andrew S.; Kortepeter, Mark G.; Moran, Kimberly A.

    2007-01-01

    Acinetobacter species are becoming a major cause of nosocomial infections, including hospital-acquired and ventilator-associated pneumonia. Acinetobacter species have become increasingly resistant to antibiotics over the past several years and currently present a significant challenge in treating these infections. Physicians now rely on older agents, such as polymyxins (colistin), for treatment. This paper reviews the epidemiology, treatment, and prevention of this emerging pathogen. PMID:18092011

  19. Identification of antibiotic resistance genes in the multidrug-resistant Acinetobacter baumannii strain, MDR-SHH02, using whole-genome sequencing.

    PubMed

    Wang, Hualiang; Wang, Jinghua; Yu, Peijuan; Ge, Ping; Jiang, Yanqun; Xu, Rong; Chen, Rong; Liu, Xuejie

    2017-02-01

    This study aimed to investigate antibiotic resistance genes in the multidrug-resistant (MDR) Acinetobacter baumannii (A. baumanii) strain, MDR-SHH02, using whole‑genome sequencing (WGS). The antibiotic resistance of MDR-SHH02 isolated from a patient with breast cancer to 19 types of antibiotics was determined using the Kirby‑Bauer method. WGS of MDR-SHH02 was then performed. Following quality control and transcriptome assembly, functional annotation of genes was conducted, and the phylogenetic tree of MDR-SHH02, along with another 5 A. baumanii species and 2 Acinetobacter species, was constructed using PHYLIP 3.695 and FigTree v1.4.2. Furthermore, pathogenicity islands (PAIs) were predicted by the pathogenicity island database. Potential antibiotic resistance genes in MDR-SHH02 were predicted based on the information in the Antibiotic Resistance Genes Database (ARDB). MDR-SHH02 was found to be resistant to all of the tested antibiotics. The total draft genome length of MDR-SHH02 was 4,003,808 bp. There were 74.25% of coding sequences to be annotated into 21 of the Clusters of Orthologous Groups (COGs) of protein terms, such as 'transcription' and 'amino acid transport and metabolism'. Furthermore, there were 45 PAIs homologous to the sequence MDRSHH02000806. Additionally, a total of 12 gene sequences in MDR-SHH02 were highly similar to the sequences of antibiotic resistance genes in ARDB, including genes encoding aminoglycoside‑modifying enzymes [e.g., aac(3)-Ia, ant(2'')‑Ia, aph33ib and aph(3')-Ia], β-lactamase genes (bl2b_tem and bl2b_tem1), sulfonamide-resistant dihydropteroate synthase genes (sul1 and sul2), catb3 and tetb. These results suggest that numerous genes mediate resistance to various antibiotics in MDR-SHH02, and provide a clinical guidance for the personalized therapy of A. baumannii-infected patients.

  20. Identification of antibiotic resistance genes in the multidrug-resistant Acinetobacter baumannii strain, MDR-SHH02, using whole-genome sequencing

    PubMed Central

    Wang, Hualiang; Wang, Jinghua; Yu, Peijuan; Ge, Ping; Jiang, Yanqun; Xu, Rong; Chen, Rong; Liu, Xuejie

    2017-01-01

    This study aimed to investigate antibiotic resistance genes in the multidrug-resistant (MDR) Acinetobacter baumannii (A. baumanii) strain, MDR-SHH02, using whole-genome sequencing (WGS). The antibiotic resistance of MDR-SHH02 isolated from a patient with breast cancer to 19 types of antibiotics was determined using the Kirby-Bauer method. WGS of MDR-SHH02 was then performed. Following quality control and transcriptome assembly, functional annotation of genes was conducted, and the phylogenetic tree of MDR-SHH02, along with another 5 A. baumanii species and 2 Acinetobacter species, was constructed using PHYLIP 3.695 and FigTree v1.4.2. Furthermore, pathogenicity islands (PAIs) were predicted by the pathogenicity island database. Potential antibiotic resistance genes in MDR-SHH02 were predicted based on the information in the Antibiotic Resistance Genes Database (ARDB). MDR-SHH02 was found to be resistant to all of the tested antibiotics. The total draft genome length of MDR-SHH02 was 4,003,808 bp. There were 74.25% of coding sequences to be annotated into 21 of the Clusters of Orthologous Groups (COGs) of protein terms, such as 'transcription' and 'amino acid transport and metabolism'. Furthermore, there were 45 PAIs homologous to the sequence MDRSHH02000806. Additionally, a total of 12 gene sequences in MDR-SHH02 were highly similar to the sequences of antibiotic resistance genes in ARDB, including genes encoding aminoglycoside-modifying enzymes [e.g., aac(3)-Ia, ant(2″)-Ia, aph33ib and aph(3′)-Ia], β-lactamase genes (bl2b_tem and bl2b_tem1), sulfonamide-resistant dihydropteroate synthase genes (sul1 and sul2), catb3 and tetb. These results suggest that numerous genes mediate resistance to various antibiotics in MDR-SHH02, and provide a clinical guidance for the personalized therapy of A. baumannii-infected patients. PMID:28035408

  1. The K1 Capsular Polysaccharide of Acinetobacter baumannii Strain 307-0294 Is a Major Virulence Factor ▿

    PubMed Central

    Russo, Thomas A.; Luke, Nicole R.; Beanan, Janet M.; Olson, Ruth; Sauberan, Shauna L.; MacDonald, Ulrike; Schultz, L. Wayne; Umland, Timothy C.; Campagnari, Anthony A.

    2010-01-01

    Acinetobacter baumannii is a pathogen of increasing medical importance with a propensity to be multidrug resistant, thereby making treatment challenging. Little is known of virulence traits in A. baumannii. To identify virulence factors and potential drug targets, random transposon (Tn) mutants derived from the A. baumannii strain AB307-0294 were screened to identify genes essential for growth in human ascites fluid in vitro, an inflammatory exudative fluid. These studies led to the identification of two genes that were predicted to be required for capsule polymerization and assembly. The first, ptk, encodes a putative protein tyrosine kinase (PTK), and the second, epsA, encodes a putative polysaccharide export outer membrane protein (EpsA). Monoclonal antibodies used in flow cytometric and Western analyses confirmed that these genes are required for a capsule-positive phenotype. A capsule-positive phenotype significantly optimized growth in human ascites fluid, survival in human serum, and survival in a rat soft tissue infection model. Importantly, the clearance of the capsule-minus mutants AB307.30 (ptk mutant, capsule minus) and AB307.45 (epsA mutant, capsule minus) was complete and durable. These data demonstrated that the K1 capsule from AB307-0294 was an important protectin. Further, these data suggested that conserved proteins, which contribute to the capsule-positive phenotype, are potential antivirulence drug targets. Therefore, the results from this study have important biologic and translational implications and, to the best of our knowledge, are the first to address the role of capsule in the pathogenesis of A. baumannii infection. PMID:20643860

  2. Unusual features of the sequences of copies of the 16S-23S rRNA internal transcribed spacer regions of Acinetobacter bereziniae, Acinetobacter guillouiae and Acinetobacter baylyi arise from horizontal gene transfer events.

    PubMed

    Maslunka, Christopher; Gürtler, Volker; Seviour, Robert

    2015-02-01

    The highly variable nature of the internal transcribed spacer region (ITS) has been claimed to represent an ideal target for designing species-specific probes/primers capable of differentiating between closely related Acinetobacter species. However, several Acinetobacter species contain multiple ITS copies of variable lengths, and these include Acinetobacter bereziniae, Acinetobacter guillouiae and Acinetobacter baylyi. This study shows these length variations result from inter-genomic insertion/deletion events (indels) involving horizontal transfer of ITS fragments of other Acinetobacter species and possibly unrelated bacteria, as shown previously by us. In some instances, indel incorporation results in the loss of probe target sites in the recipient cell ITS. In other cases, some indel sequences contain target sites for probes designed from a single ITS sequence to target other Acinetobacter species. Hence, these can generate false positives. The largest of the indels that remove probe sites is 683 bp (labelled bay/i1-0), and it derives from the horizontal transfer of a complete ITS between A. bereziniae BCRC15423(T) and A. baylyi strain ADP1. As a consequence, ITS sequencing or fingerprinting cannot be used to distinguish between the 683 bp ITS in these two strains.

  3. Draft Genome Sequence of Acinetobacter oleivorans PF1, a Diesel-Degrading and Plant-Growth-Promoting Endophytic Strain Isolated from Poplar Trees Growing on a Diesel-Contaminated Plume

    PubMed Central

    Gkorezis, Panagiotis; Rineau, Francois; Van Hamme, Jonathan; Daghio, Matteo; Thijs, Sofie; Weyens, Nele

    2015-01-01

    We report the 3.7-Mb draft genome of Acinetobacter oleivorans strain PF1, a hydrocarbonoclastic Gram-negative bacterium in the class Gammaproteobacteria, isolated from poplar trees growing on a diesel-contaminated plume at the Ford Motor Company site in Genk, Belgium. Strain PF1 is a potent plant-growth promoter, useful for diesel fuel phytoremediation applications. PMID:25657268

  4. [Acinetobacter spp].

    PubMed

    Matsunaga, Naohisa

    2012-02-01

    Acinetobacter species are aerobic, glucose non-fermenting gram-negative rods, and ubiquitous in the environment. Acinetobacter spp. can survive for months on dry surfaces. Acinetobacter spp. have been grown from skin, pharynx, sputum, urine and feces. The most common Acinetobacter infection is pneumonia. According to Japan Nosocomial Infection Surveillance, 0.34% of the Acinetobacter spp. was multidrug-resistant in 2010. In Japan, Acinetobacter spp. whose imipenem MICs were > or = 16 microg/mL, amikacin > or = 32 microg/mL, and ciprofloxacin > or = 4 microg/mL were defined as multidrug-resistant Acinetobacter species (MDRA) in 2011 in the amended Infectious Diseases Control Law. Break-point Checkerboard Plate can help to infer an effective combination antimicrobial therapy. A selective medium for the isolation of MDRA is a great tool for active surveillance cultures. Treatment options for MDRA infections in Japan are very limited, because colistin, polymyxin B, or tigecycline is not approved. Keys to control MDRA are high levels of compliance with standard and contact precautions, appropriate cleaning and disinfection of the environment, and judicious antimicrobial use.

  5. Wax Ester Production from n-Alkanes by Acinetobacter sp. Strain M-1: Ultrastructure of Cellular Inclusions and Role of Acyl Coenzyme A Reductase

    PubMed Central

    Ishige, Takeru; Tani, Akio; Takabe, Keiji; Kawasaki, Kazunori; Sakai, Yasuyoshi; Kato, Nobuo

    2002-01-01

    Acinetobacter sp. strain M-1 accumulated a large amount of wax esters from an n-alkane under nitrogen-limiting conditions. Under the optimized conditions with n-hexadecane as the substrate, the amount of hexadecyl hexadecanoate in the cells reached 0.17 g/g of cells (dry weight). Electron microscopic analysis revealed that multilayered disk-shaped intracellular inclusions were formed concomitant with wax ester formation. The contribution of acyl-CoA reductase to wax ester synthesis was evaluated by gene disruption analysis. PMID:11872467

  6. Investigation of metallo-beta-lactamase producing strains of Pseudomonas aeruginosa and Acinetobacter baumannii by E-test, disk synergy and PCR.

    PubMed

    Aktaş, Zerrin; Kayacan, Ciğdem Bal

    2008-01-01

    Carbapenem non-susceptible Pseudomonas aeruginosa and Acinetobacter baumannii strains were tested for the presence of metallo-beta-lactamases (MBLs) by EDTA-synergy screening. Imipenem hydrolysis was investigated by a bioassay and IMP-/VIM-encoding genes by PCR. No bla(IMP/VIM) related genes or imipenemase activity were detected although E-test found all strains as MBL-positive. Disk synergy tests with 0.5 M EDTA determined 63.6-100%, while those with 0.1 M EDTA detected 0-7.7% of isolates as MBL producers. Most strains were susceptible to EDTA. In conclusion, for MBL-screening purposes, EDTA-synergy results change with molarity of EDTA, but even if some false positives are encountered, 0.1 M EDTA seems to be acceptable.

  7. Pathogenic Acinetobacter Species have a Functional Type I Secretion System and Contact-Dependent Inhibition Systems.

    PubMed

    Harding, Christian M; Pulido, Marina R; Di Venanzio, Gisela; Kinsella, Rachel L; Webb, Andrew I; Scott, Nichollas E; Pachón, Jerónimo; Feldman, Mario F

    2017-04-03

    Pathogenic Acinetobacter species, including A. baumannii and A. nosocomialis, are opportunistic human pathogens of increasing relevance worldwide. Although their mechanisms of drug resistance are well studied, the virulence factors that govern Acinetobacter pathogenesis are incompletely characterized. Here we define the complete secretome of A. nosocomialis strain M2 in minimal media and demonstrate that pathogenic Acinetobacter species produce both a functional type I secretion system (T1SS) and a contact dependent inhibition (CDI) system. Using bioinformatics, quantitative proteomics, and mutational analyses we show that Acinetobacter uses its T1SS for exporting two putative T1SS effectors, an RTX-Serralysin-like toxin and the biofilm associated protein (Bap). Moreover, we found that mutation of any component of the T1SS system abrogated type VI secretion activity under nutrient-limited conditions, indicating a previously unrecognized crosstalk between these two systems. We also demonstrate that the Acinetobacter T1SS is required for biofilm formation. Lastly, we show that both A. nosocomialis and A. baumannii produce functioning CDI systems that mediate growth inhibition of sister cells lacking the cognate immunity protein. The Acinetobacter CDI systems are widely distributed across pathogenic Acinetobacter species, with many A. baumannii isolates harboring two distinct CDI systems. Collectively, these data demonstrate the power of differential, quantitative proteomics approaches to study secreted proteins, define the role of previously uncharacterized protein export systems, and observe crosstalk between secretion systems in the pathobiology of medically relevant Acinetobacter The data are available via ProteomeXchange with identifier PXD005881.

  8. Thio Wax Ester Biosynthesis Utilizing the Unspecific Bifunctional Wax Ester Synthase/Acyl Coenzyme A:Diacylglycerol Acyltransferase of Acinetobacter sp. Strain ADP1

    PubMed Central

    Uthoff, Stefan; Stöveken, Tim; Weber, Nikolaus; Vosmann, Klaus; Klein, Erika; Kalscheuer, Rainer; Steinbüchel, Alexander

    2005-01-01

    The bifunctional wax ester synthase/acyl coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS/DGAT) from Acinetobacter sp. strain ADP1 (formerly Acinetobacter calcoaceticus ADP1) mediating the biosyntheses of wax esters and triacylglycerols was used for the in vivo and in vitro biosynthesis of thio wax esters and dithio wax esters. For in vitro biosynthesis, 5′His6WS/DGAT comprising an N-terminal His6 tag was purified from the soluble protein fraction of Escherichia coli Rosetta(DE3)pLysS (pET23a::5′His6atf). By employing SP-Sepharose high-pressure and Ni-nitrilotriacetic acid fast-protein liquid chromatographies, a 19-fold enrichment with a final specific activity of 165.2 nmol mg of protein−1 min−1 was achieved by using 1-hexadecanol and palmitoyl-CoA as substrates. Incubation of purified 5′His6WS/DGAT with 1-hexadecanethiol and palmitoyl-CoA as substrates resulted in the formation of palmitic acid hexadecyl thio ester (10.4% relative specific activity of a 1-hexadecanol control). Utilization of 1,8-octanedithiol and palmitoyl-CoA as substrates led to the formation of 1-S-monopalmitoyloctanedithiol and minor amounts of 1,8-S-dipalmitoyloctanedithiol (59.3% relative specific activity of a 1-hexadecanol control). The latter dithio wax ester was efficiently produced when 1-S-monopalmitoyloctanedithiol and palmitoyl-CoA were used as substrates (13.4% specific activity relative to that of a 1-hexadecanol control). For the in vivo biosynthesis of thio wax esters, the knockout mutant Acinetobacter sp. strain ADP1acr1ΩKm, which is unable to produce fatty alcohols, was used. Cultivation of Acinetobacter sp. strain ADP1acr1ΩKm in the presence of gluconate, 1-hexadecanethiol, and oleic acid in nitrogen-limited mineral salts medium resulted in the accumulation of unusual thio wax esters that accounted for around 1.19% (wt/wt) of the cellular dry weight and consisted mainly of oleic acid hexadecyl thioester as revealed by gas chromatography-mass spectrometry

  9. Genome Sequence of Acinetobacter baumannii Strain D36, an Antibiotic-Resistant Isolate from Lineage 2 of Global Clone 1

    PubMed Central

    Hamidian, Mohammad; Hawkey, Jane

    2015-01-01

    Multiply antibiotic-resistant Acinetobacter baumannii isolate D36 was recovered in Australia in 2008 and belongs to a distinct lineage of global clone 1 (GC1). Here, we present the complete 4.13 Mbp genome sequence (chromosome plus 4 plasmids), generated via long read sequencing (PacBio). PMID:26679588

  10. Distribution and molecular profiling of class 1 integrons in MDR Acinetobacter baumannii isolates and whole genome-based analysis of antibiotic resistance mechanisms in a representative strain.

    PubMed

    Zhu, Yuying; Yi, Yong; Liu, Fei; Lv, Na; Yang, Xi; Li, Jing; Hu, Yongfei; Zhu, Baoli

    2014-11-01

    The class 1 integron is an important driver of the nosocomial dissemination of multidrug-resistant (MDR) bacteria, such as Acinetobacters. In this study, we characterized the gene cassette arrays of class 1 integrons in Acinetobacter baumannii, where the detailed structure of these integrons for 38 clinical strains was analyzed. The results showed that there are three types of gene cassette arrays that are carried by different class 1 integrons, among them the aac(6')-IId-catB8-aadA1 array was the most prevalent. For detailed analysis of the integron structure, whole genome sequencing was carried out on strain AB16, and it was found that a single integron on its chromosome has a partial Tn21 transposon in its 5' flanking region and two complete copies of the insertion element IS26 in both the 5' and 3' flanking regions, indicating that the integron could be acquired by horizontal gene transfer. Furthermore, there is one resistance island AbaR22, one bla gene containing a transposon, four intrinsic resistant genes and one efflux pump that together confer six types of antibiotic resistance.

  11. Insight into stereochemistry of a new IMP allelic variant (IMP-55) metallo-β-lactamase identified in a clinical strain of Acinetobacter baumannii.

    PubMed

    Shakibaie, Mohammad Reza; Azizi, Omid; Shahcheraghi, Fereshteh

    2017-07-01

    Metallo-β-lactamases (MBLs) such as IMPs are broad-spectrum β-lactamases that inactivate virtually all β-lactam antibiotics including carbapenems. In this study, we investigated the hydrolytic activity, phylogenetic relationship, three dimensional (3D) structure including zinc binding motif of a new IMP variant (IMP-55) identified in a clinical strain of Acinetobacter baumannii (AB). AB strain 56 was isolated from an adult ICU of a teaching hospital in Kerman, Iran. It exhibited MIC 32μg/ml to imipenem and showed MBL activity. Hydrolytic property of the MBL enzyme was measured phenotypically. Presence of blaIMP gene encoded by class 1 integrons was detected by PCR-sequencing. Phylogenetic tree of IMP protein was constructed using the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) and 3D model including zinc binding motif was predicted by bioinformatics softwares. Analysis of IMP sequence led to the identification of a novel IMP-type designated as IMP-55 (GenBank: KU299753.1; UniprotKB: A0A0S2MTX2). Impact in term of hydrolytic activity compared to the closest variants suggested efficient imipenem hydrolysis by this enzyme. Evolutionary distance matrix assessment indicated that IMP-55 protein is not closely related to other A. baumannii IMPs, however, shared 98% homology with Escherichia coli IMP-30 (UniprotKB: A0A0C5PJR0) and Pseudomonas aeruginosa IMP-1 (UniprotKB: Q19KT1). It consisted of five α-helices, ten β-sheets and six loops. A monovalent zinc ion attached to core of enzyme via His95, His97, His157 and Cys176. Multiple amino acid sequence alignments and mutational trajectory with reported IMPs showed 4 amino acid substitutions at positions 12(Phe→Ile), 31(Asp→Glu), 172(Leu→Phe) and 185(Asn→Lys). We suggest that the pleiotropic effect of mutations due to frequent administration of imipenem is responsible for emergence of new IMP variant in our hospitals. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Induction of Diverse Bioactive Secondary Metabolites from the Mangrove Endophytic Fungus Trichoderma sp. (Strain 307) by Co-Cultivation with Acinetobacter johnsonii (Strain B2)

    PubMed Central

    Zhang, Liuhong; Niaz, Shah Iram; Khan, Dilfaraz; Wang, Zhen; Zhu, Yonghong; Zhou, Haiyun; Lin, Yongcheng; Li, Jing; Liu, Lan

    2017-01-01

    Two new sesquiterpenes, microsphaeropsisin B (1) and C (2), and two new de-O-methyllasiodiplodins, (3R, 7R)-7-hydroxy-de-O-methyllasiodiplodin (4) and (3R)-5-oxo-de-O-methyllasiodiplodin (5), together with one new natural product (6) and twelve known compounds (3, 7–17), were isolated from the co-cultivation of mangrove endophytic fungus Trichoderma sp. 307 and aquatic pathogenic bacterium Acinetobacter johnsonii B2. Their structures, including absolute configurations, were elucidated by extensive analysis of spectroscopic data, electronic circular dichroism, Mo2(AcO)4-induced circular dichroism, and comparison with reported data. All of the isolated compounds were tested for their α-glucosidase inhibitory activity and cytotoxicity. New compounds 4 and 5 exhibited potent α-glucosidase inhibitory activity with IC50 values of 25.8 and 54.6 µM, respectively, which were more potent than the positive control (acarbose, IC50 = 703.8 µM). The good results of the tested bioactivity allowed us to explore α-glucosidase inhibitors in lasiodiplodins. PMID:28208607

  13. Multidrug Resistant Acinetobacter

    PubMed Central

    Manchanda, Vikas; Sanchaita, Sinha; Singh, NP

    2010-01-01

    Emergence and spread of Acinetobacter species, resistant to most of the available antimicrobial agents, is an area of great concern. It is now being frequently associated with healthcare associated infections. Literature was searched at PUBMED, Google Scholar, and Cochrane Library, using the terms ‘Acinetobacter Resistance, multidrug resistant (MDR), Antimicrobial Therapy, Outbreak, Colistin, Tigecycline, AmpC enzymes, and carbapenemases in various combinations. The terms such as MDR, Extensively Drug Resistant (XDR), and Pan Drug Resistant (PDR) have been used in published literature with varied definitions, leading to confusion in the correlation of data from various studies. In this review various mechanisms of resistance in the Acinetobacter species have been discussed. The review also probes upon the current therapeutic options, including combination therapies available to treat infections due to resistant Acinetobacter species in adults as well as children. There is an urgent need to enforce infection control measures and antimicrobial stewardship programs to prevent the further spread of these resistant Acinetobacter species and to delay the emergence of increased resistance in the bacteria. PMID:20927292

  14. Isolation and characterization of a novel oxygenase that catalyzes the first step of n-alkane oxidation in Acinetobacter sp. strain M-1.

    PubMed Central

    Maeng, J H; Sakai, Y; Tani, Y; Kato, N

    1996-01-01

    In the Finnerty pathway for n-alkane, oxidation in Acinetobacter sp., n-alkanes are postulated to be attacked by a dioxygenase and the product, n-alkyl hydroperoxide, is further metabolized to the corresponding aldehyde via the peroxy acid [W. R. Finnerty, P. 184-188, in A. H. Applewhite (ed.), Proceedings of the World Conference on Biotechnology for the Fats and Oil Industry, 1988]. However, no biochemical evidence regarding the first-step reaction is available. In this study, we found a novel n-alkane-oxidizing enzyme that requires only molecular oxygen, i.e., not NAD(P)H, in our isolate, Acinetobacter sp. strain M-1, and purified it to apparent homogeneity by gel electrophoresis. The purified enzyme is a homodimeric protein with a molecular mass of 134 kDa, contains 1 mol of flavin adenine dinucleotide per mol of subunit, and requires CU2+ for its activity. The enzyme uses n-alkanes ranging in length from 10 to 30 carbon atoms and is also active toward n-alkenes (C12 to C20) and some aromatic compounds with substituted alkyl groups but not toward a branched alkane, alcohol, or aldehyde. Transient accumulation of n-alkyl hydroperoxide was detected in the course of the reaction, and no oxygen radical scavengers affected the enzyme activity. From these properties, the enzyme is most probably a dioxygenase that catalyzes the introduction of two atoms of oxygen to the substrate, leading to the formation of the corresponding n-alkyl hydroperoxide. The enzymatic evidence strongly supports the existence of an n-alkane oxidation pathway, which is initiated by a dioxygenase reaction, in Acinetobacter spp. PMID:8682768

  15. Optimization of fermentation medium for the production of atrazine degrading strain Acinetobacter sp. DNS(32) by statistical analysis system.

    PubMed

    Zhang, Ying; Wang, Yang; Wang, Zhi-Gang; Wang, Xi; Guo, Huo-Sheng; Meng, Dong-Fang; Wong, Po-Keung

    2012-01-01

    Statistical experimental designs provided by statistical analysis system (SAS) software were applied to optimize the fermentation medium composition for the production of atrazine-degrading Acinetobacter sp. DNS(32) in shake-flask cultures. A "Plackett-Burman Design" was employed to evaluate the effects of different components in the medium. The concentrations of corn flour, soybean flour, and K(2)HPO(4) were found to significantly influence Acinetobacter sp. DNS(32) production. The steepest ascent method was employed to determine the optimal regions of these three significant factors. Then, these three factors were optimized using central composite design of "response surface methodology." The optimized fermentation medium composition was composed as follows (g/L): corn flour 39.49, soybean flour 25.64, CaCO(3) 3, K(2)HPO(4) 3.27, MgSO(4)·7H(2)O 0.2, and NaCl 0.2. The predicted and verifiable values in the medium with optimized concentration of components in shake flasks experiments were 7.079 × 10(8) CFU/mL and 7.194 × 10(8) CFU/mL, respectively. The validated model can precisely predict the growth of atrazine-degraing bacterium, Acinetobacter sp. DNS(32).

  16. Optimization of Fermentation Medium for the Production of Atrazine Degrading Strain Acinetobacter sp. DNS32 by Statistical Analysis System

    PubMed Central

    Zhang, Ying; Wang, Yang; Wang, Zhi-Gang; Wang, Xi; Guo, Huo-Sheng; Meng, Dong-Fang; Wong, Po-keung

    2012-01-01

    Statistical experimental designs provided by statistical analysis system (SAS) software were applied to optimize the fermentation medium composition for the production of atrazine-degrading Acinetobacter sp. DNS32 in shake-flask cultures. A “Plackett-Burman Design” was employed to evaluate the effects of different components in the medium. The concentrations of corn flour, soybean flour, and K2HPO4 were found to significantly influence Acinetobacter sp. DNS32 production. The steepest ascent method was employed to determine the optimal regions of these three significant factors. Then, these three factors were optimized using central composite design of “response surface methodology.” The optimized fermentation medium composition was composed as follows (g/L): corn flour 39.49, soybean flour 25.64, CaCO3 3, K2HPO4 3.27, MgSO4·7H2O 0.2, and NaCl 0.2. The predicted and verifiable values in the medium with optimized concentration of components in shake flasks experiments were 7.079 × 108 CFU/mL and 7.194 × 108 CFU/mL, respectively. The validated model can precisely predict the growth of atrazine-degraing bacterium, Acinetobacter sp. DNS32. PMID:23093851

  17. Transformation of Acinetobacter sp. Strain BD413(pFG4ΔnptII) with Transgenic Plant DNA in Soil Microcosms and Effects of Kanamycin on Selection of Transformants

    PubMed Central

    Nielsen, Kaare M.; van Elsas, Jan D.; Smalla, Kornelia

    2000-01-01

    Here we show that horizontal transfer of DNA, extracted from transgenic sugar beets, to bacteria, based on homologous recombination, can occur in soil. Restoration of a 317-bp-deleted nptII gene in Acinetobacter sp. strain BD413(pFG4) cells incubated in sterile soil microcosms was detected after addition of nutrients and transgenic plant DNA encoding a functional nptII gene conferring bacterial kanamycin resistance. Selective effects of the addition of kanamycin on the population dynamics of Acinetobacter sp. cells in soil were found, and high concentrations of kanamycin reduced the CFU of Acinetobacter sp. cells from 109 CFU/g of soil to below detection. In contrast to a chromosomal nptII-encoded kanamycin resistance, the pFG4-generated resistance was found to be unstable over a 31-day incubation period in vitro. PMID:10698801

  18. Structure of a short-chain dehydrogenase/reductase (SDR) within a genomic island from a clinical strain of Acinetobacter baumannii.

    PubMed

    Shah, Bhumika S; Tetu, Sasha G; Harrop, Stephen J; Paulsen, Ian T; Mabbutt, Bridget C

    2014-10-01

    Over 15% of the genome of an Australian clinical isolate of Acinetobacter baumannii occurs within genomic islands. An uncharacterized protein encoded within one island feature common to this and other International Clone II strains has been studied by X-ray crystallography. The 2.4 Å resolution structure of SDR-WM99c reveals it to be a new member of the classical short-chain dehydrogenase/reductase (SDR) superfamily. The enzyme contains a nucleotide-binding domain and, like many other SDRs, is tetrameric in form. The active site contains a catalytic tetrad (Asn117, Ser146, Tyr159 and Lys163) and water molecules occupying the presumed NADP cofactor-binding pocket. An adjacent cleft is capped by a relatively mobile helical subdomain, which is well positioned to control substrate access.

  19. Draft Genome Sequence of Acinetobacter sp. Strain BMW17, a Cellulolytic and Plant Growth-Promoting Bacterium Isolated from the Rhizospheric Region of Phragmites karka of Chilika Lake, India

    PubMed Central

    Mishra, Samir R.; Ray, Lopamudra; Panda, Ananta Narayan; Sahu, Neha; Xess, Sonal S.; Jadhao, Sudhir; Suar, Mrutyunjay; Adhya, Tapan Kumar; Rastogi, Gurdeep; Pattnaik, Ajit Kumar

    2016-01-01

    We report the 3.16 Mb draft genome of Acinetobacter sp. strain BMW17, a Gram-negative bacterium in the class of Gammaproteobacteria, isolated from the rhizospheric region of Phragmites karka, an invasive weed in Chilika Lake, Odisha, India. The strain BMW17T is capable of degrading cellulose and is also an efficient plant growth promoter that can be useful for various phytoremedial and commercial applications. PMID:27365343

  20. Draft Genome Sequence of Acinetobacter sp. Strain BMW17, a Cellulolytic and Plant Growth-Promoting Bacterium Isolated from the Rhizospheric Region of Phragmites karka of Chilika Lake, India.

    PubMed

    Mishra, Samir R; Ray, Lopamudra; Panda, Ananta Narayan; Sahu, Neha; Xess, Sonal S; Jadhao, Sudhir; Suar, Mrutyunjay; Adhya, Tapan Kumar; Rastogi, Gurdeep; Pattnaik, Ajit Kumar; Raina, Vishakha

    2016-06-30

    We report the 3.16 Mb draft genome of Acinetobacter sp. strain BMW17, a Gram-negative bacterium in the class of Gammaproteobacteria, isolated from the rhizospheric region of Phragmites karka, an invasive weed in Chilika Lake, Odisha, India. The strain BMW17(T) is capable of degrading cellulose and is also an efficient plant growth promoter that can be useful for various phytoremedial and commercial applications.

  1. In vivo activity of vancomycin combined with colistin against multidrug-resistant strains of Acinetobacter baumannii in a Galleria mellonella model.

    PubMed

    Yang, Haifei; Lv, Na; Hu, Lifen; Liu, Yanyan; Cheng, Jun; Ye, Ying; Li, Jiabin

    2016-01-01

    With increasing antibiotic resistance, the selection of effective treatment of A. baumannii infections is particularly challenging. This study assessed the activities of the combination of vancomycin and colistin combination in vitro and in vivo using a Galleria mellonella model against four colistin-susceptible or colistin-resistant A. baumannii strains. In checkerboard assays, synergy was observed between vancomycin and colistin for all four strains tested (0.156 ≤ Fractional inhibitory concentration indices [FICI] ≤ 0.281). In time-kill assays, the combination showed continued bactericidal activity and synergy after 24 h for colistin-susceptible strains. For colistin-resistant strains, the combination resulted in bactericidal activity within 8 h, but sustained bacterial re-growth was then observed. Treatment of G. mellonella larvae infected with lethal doses of A. baumannii (except 19606R) resulted in significantly increased survival rates when vancomycin was given with colistin compared to colistin treatment alone (p < 0.05). These findings suggest that regimens containing vancomycin may be useful for infections due to multidrug-resistant Acinetobacter baumannii.

  2. Radiation resistance of acinetobacter spp.

    NASA Astrophysics Data System (ADS)

    Whitby, James L.

    1995-02-01

    The radiation resistance of 78 different strains of Acinetobacter sp. 42 from clinical isolates and 36 from other sources were compared with 15 clinical isolates and 12 other strains from Denmark. None of the Canadian strains was as resistant as resistant-enhanced Danish strains. Four strains had D 10 values of 3.1-3.6 kGy. Irradiated and unirradiated cells from all strains grew well, when cultured in Trypticase-Soy Broth at 30°C. Most cultures grew after overnight incubation. It was concluded that there would be no difficulty in detecting these strains, using ISO methodology for establishing the radiation sterilization dose for devices.

  3. An Amphipathic Undecapeptide with All d-Amino Acids Shows Promising Activity against Colistin-Resistant Strains of Acinetobacter baumannii and a Dual Mode of Action.

    PubMed

    Oddo, Alberto; Thomsen, Thomas T; Kjelstrup, Susanne; Gorey, Ciara; Franzyk, Henrik; Frimodt-Møller, Niels; Løbner-Olesen, Anders; Hansen, Paul R

    2015-11-16

    Multiple strains of Acinetobacter baumannii have developed multidrug resistance (MDR), leaving colistin as the only effective treatment. The cecropin-α-melittin hybrid BP100 (KKLFKKILKYL-NH2) and its analogs have previously shown activity against a wide array of plant and human pathogens. In this study, we investigated the in vitro antibacterial activities of 18 BP100 analogs (four known and 14 new) against the MDR A. baumannii strain ATCC BAA-1605, as well as against a number of other clinically relevant human pathogens. Selected peptides were further evaluated against strains of A. baumannii that acquired resistance to colistin due to mutations of the lpxC, lpxD, pmrA, and pmrB genes. The novel analogue BP214 showed antimicrobial activity at 1 to 2 μM and a hemolytic 50% effective concentration (EC50) of >150 μM. The lower activity of its enantiomer suggests a dual, specific and nonspecific mode of action. Interestingly, colistin behaved antagonistically to BP214 when pmrAB and lpxC mutants were challenged. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  4. Acinetobacter gandensis sp. nov. isolated from horse and cattle.

    PubMed

    Smet, Annemieke; Cools, Piet; Krizova, Lenka; Maixnerova, Martina; Sedo, Ondrej; Haesebrouck, Freddy; Kempf, Marie; Nemec, Alexandr; Vaneechoutte, Mario

    2014-12-01

    We previously reported the presence of an OXA-23 carbapenemase in an undescribed species of the genus Acinetobacter isolated from horse dung at the Faculty of Veterinary Medicine, Ghent University, Belgium. Here we include six strains to corroborate the delineation of this taxon by phenotypic characterization, DNA-DNA hybridization, 16S rRNA gene and rpoB sequence analysis, % G+C determination, MALDI-TOF MS and fatty acid analysis. The nearly complete 16S rRNA gene sequence of strain UG 60467(T) showed the highest similarities with those of the type strains of Acinetobacter bouvetii (98.4 %), Acinetobacter haemolyticus (97.7 %), and Acinetobacter schindleri (97.2 %). The partial rpoB sequence of strain UG 60467(T) showed the highest similarities with 'Acinetobacter bohemicus' ANC 3994 (88.6 %), A. bouvetii NIPH 2281 (88.6 %) and A. schindleri CIP 107287T (87.3 %). Whole-cell MALDI-TOF MS analyses supported the distinctness of the group at the protein level. The predominant fatty acids of strain UG 60467(T) were C12 : 0 3-OH, C12 : 0, C16 : 0, C18 : 1ω9c and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). Strains UG 60467(T) and UG 60716 showed a DNA-DNA relatedness of 84 % with each other and a DNA-DNA relatedness with A. schindleri LMG 19576(T) of 17 % and 20 %, respectively. The DNA G+C content of strain UG 60467(T) was 39.6 mol%. The name Acinetobacter gandensis sp. nov. is proposed for the novel taxon. The type strain is UG 60467(T) ( = ANC 4275(T) = LMG 27960(T) = DSM 28097(T)). © 2014 IUMS.

  5. Purification and Characterization of Catechol 1,2-Dioxygenase from Acinetobacter sp. Y64 Strain and Escherichia coli Transformants.

    PubMed

    Lin, J; Milase, R N

    2015-12-01

    This study intends to purify and characterize catechol 1,2-dioxygenase (C1,2O) of phenol-degrading Acinetobacter sp. Y64 and of E. coli transformant. Acinetobacter sp. Y64 was capable of degrading 1000 mg/L of phenol within 14 ± 2 h at 30 °C, 160 rpm and pH of 7. One C1,2O of 36 kDa was purified using ammonium sulphate precipitation and Hitrap QFF column chromatograph with 49% recovery and a 10.6-fold increase in purity. Purified Y64 C1,2O had temperature and pH optimum at 37 °C and pH 7.7 respectively with the Michaelis constant of 17.53 µM and the maximal velocity of 1.95 U/mg, respectively. The presence of Fe(3+) or Fe(2+) enhanced the activity of Y64 C1,2O while other compounds such as Ca(2+), and EDTA had an inhibitory effect. 80% of C1,2O activity remained using 4-nitrocatechol as substrate while 2% remained using 3-methylcatechol compared with that using catechol. Y64 catA gene encoding C1,2O was amplified using PCR cloned into pET22b vector and expressed in Escherichia coli BL21 DE3 (pLysS) after transformation. Purified and cloned Y64 C1,2O show no significant differences in the biochemical properties. The phylogenetic tree based on the protein sequences indicates that these C1,2Os possess a common ancestry.

  6. Energetics of alanine, lysine, and proline transport in cytoplasmic membranes of the polyphosphate-accumulating Acinetobacter johnsonii strain 210A.

    PubMed Central

    Van Veen, H W; Abee, T; Kleefsman, A W; Melgers, B; Kortstee, G J; Konings, W N; Zehnder, A J

    1994-01-01

    Amino acid transport in right-side-out membrane vesicles of Acinetobacter johnsonii 210A was studied. L-Alanine, L-lysine, and L-proline were actively transported when a proton motive force of -76 mV was generated by the oxidation of glucose via the membrane-bound glucose dehydrogenase. Kinetic analysis of amino acid uptake at concentrations of up to 80 microM revealed the presence of a single transport system for each of these amino acids with a Kt of less than 4 microM. The mode of energy coupling to solute uptake was analyzed by imposition of artificial ion diffusion gradients. The uptake of alanine and lysine was driven by a membrane potential and a transmembrane pH gradient. In contrast, the uptake of proline was driven by a membrane potential and a transmembrane chemical gradient of sodium ions. The mechanistic stoichiometry for the solute and the coupling ion was close to unity for all three amino acids. The Na+ dependence of the proline carrier was studied in greater detail. Membrane potential-driven uptake of proline was stimulated by Na+, with a half-maximal Na+ concentration of 26 microM. At Na+ concentrations above 250 microM, proline uptake was strongly inhibited. Generation of a sodium motive force and maintenance of a low internal Na+ concentration are most likely mediated by a sodium/proton antiporter, the presence of which was suggested by the Na(+)-dependent alkalinization of the intravesicular pH in inside-out membrane vesicles. The results show that both H+ and Na+ can function as coupling ions in amino acid transport in Acinetobacter spp. PMID:8169217

  7. Pathogenic Acinetobacter: from the Cell Surface to Infinity and Beyond.

    PubMed

    Weber, Brent S; Harding, Christian M; Feldman, Mario F

    2015-12-28

    The genus Acinetobacter encompasses multiple nosocomial opportunistic pathogens that are of increasing worldwide relevance because of their ability to survive exposure to various antimicrobial and sterilization agents. Among these, Acinetobacter baumannii, Acinetobacter nosocomialis, and Acinetobacter pittii are the most frequently isolated in hospitals around the world. Despite the growing incidence of multidrug-resistant Acinetobacter spp., little is known about the factors that contribute to pathogenesis. New strategies for treating and managing infections caused by multidrug-resistant Acinetobacter strains are urgently needed, and this requires a detailed understanding of the pathobiology of these organisms. In recent years, some virulence factors important for Acinetobacter colonization have started to emerge. In this review, we focus on several recently described virulence factors that act at the bacterial surface level, such as the capsule, O-linked protein glycosylation, and adhesins. Furthermore, we describe the current knowledge regarding the type II and type VI secretion systems present in these strains.

  8. Pathogenic Acinetobacter: from the Cell Surface to Infinity and Beyond

    PubMed Central

    Weber, Brent S.; Harding, Christian M.

    2015-01-01

    The genus Acinetobacter encompasses multiple nosocomial opportunistic pathogens that are of increasing worldwide relevance because of their ability to survive exposure to various antimicrobial and sterilization agents. Among these, Acinetobacter baumannii, Acinetobacter nosocomialis, and Acinetobacter pittii are the most frequently isolated in hospitals around the world. Despite the growing incidence of multidrug-resistant Acinetobacter spp., little is known about the factors that contribute to pathogenesis. New strategies for treating and managing infections caused by multidrug-resistant Acinetobacter strains are urgently needed, and this requires a detailed understanding of the pathobiology of these organisms. In recent years, some virulence factors important for Acinetobacter colonization have started to emerge. In this review, we focus on several recently described virulence factors that act at the bacterial surface level, such as the capsule, O-linked protein glycosylation, and adhesins. Furthermore, we describe the current knowledge regarding the type II and type VI secretion systems present in these strains. PMID:26712938

  9. Reservoirs of Non-baumannii Acinetobacter Species

    PubMed Central

    Al Atrouni, Ahmad; Joly-Guillou, Marie-Laure; Hamze, Monzer; Kempf, Marie

    2016-01-01

    Acinetobacter spp. are ubiquitous gram negative and non-fermenting coccobacilli that have the ability to occupy several ecological niches including environment, animals and human. Among the different species, Acinetobacter baumannii has evolved as global pathogen causing wide range of infection. Since the implementation of molecular techniques, the habitat and the role of non-baumannii Acinetobacter in human infection have been elucidated. In addition, several new species have been described. In the present review, we summarize the recent data about the natural reservoir of non-baumannii Acinetobacter including the novel species that have been described for the first time from environmental sources and reported during the last years. PMID:26870013

  10. Structure of a short-chain dehydrogenase/reductase (SDR) within a genomic island from a clinical strain of Acinetobacter baumannii

    SciTech Connect

    Shah, Bhumika S. Tetu, Sasha G.; Harrop, Stephen J.; Paulsen, Ian T.; Mabbutt, Bridget C.

    2014-09-25

    The structure of a short-chain dehydrogenase encoded within genomic islands of A. baumannii strains has been solved to 2.4 Å resolution. This classical SDR incorporates a flexible helical subdomain. The NADP-binding site and catalytic side chains are identified. Over 15% of the genome of an Australian clinical isolate of Acinetobacter baumannii occurs within genomic islands. An uncharacterized protein encoded within one island feature common to this and other International Clone II strains has been studied by X-ray crystallography. The 2.4 Å resolution structure of SDR-WM99c reveals it to be a new member of the classical short-chain dehydrogenase/reductase (SDR) superfamily. The enzyme contains a nucleotide-binding domain and, like many other SDRs, is tetrameric in form. The active site contains a catalytic tetrad (Asn117, Ser146, Tyr159 and Lys163) and water molecules occupying the presumed NADP cofactor-binding pocket. An adjacent cleft is capped by a relatively mobile helical subdomain, which is well positioned to control substrate access.

  11. The Acinetobacter baumannii Two-Component System AdeRS Regulates Genes Required for Multidrug Efflux, Biofilm Formation, and Virulence in a Strain-Specific Manner

    PubMed Central

    Richmond, Grace E.; Evans, Laura P.; Anderson, Michele J.; Wand, Matthew E.; Bonney, Laura C.; Ivens, Alasdair; Chua, Kim Lee; Webber, Mark A.; Sutton, J. Mark; Peterson, Marnie L.

    2016-01-01

    ABSTRACT The opportunistic pathogen Acinetobacter baumannii is able to persist in the environment and is often multidrug resistant (MDR), causing difficulties in the treatment of infections. Here, we show that the two-component system AdeRS, which regulates the production of the AdeABC multidrug resistance efflux pump, is required for the formation of a protective biofilm in an ex vivo porcine mucosal model, which mimics a natural infection of the human epithelium. Interestingly, deletion of adeB impacted only on the ability of strain AYE to form a biofilm on plastic and only on the virulence of strain Singapore 1 for Galleria mellonella. RNA-Seq revealed that loss of AdeRS or AdeB significantly altered the transcriptional landscape, resulting in the changed expression of many genes, notably those associated with antimicrobial resistance and virulence interactions. For example, A. baumannii lacking AdeRS displayed decreased expression of adeABC, pil genes, com genes, and a pgaC-like gene, whereas loss of AdeB resulted in increased expression of pil and com genes and decreased expression of ferric acinetobactin transport system genes. These data define the scope of AdeRS-mediated regulation, show that changes in the production of AdeABC mediate important phenotypes controlled by AdeRS, and suggest that AdeABC is a viable target for antimicrobial drug and antibiofilm discovery. PMID:27094331

  12. Role of Acinetobactin-Mediated Iron Acquisition Functions in the Interaction of Acinetobacter baumannii Strain ATCC 19606T with Human Lung Epithelial Cells, Galleria mellonella Caterpillars, and Mice

    PubMed Central

    Gaddy, Jennifer A.; Arivett, Brock A.; McConnell, Michael J.; López-Rojas, Rafael; Pachón, Jerónimo

    2012-01-01

    Acinetobacter baumannii, which causes serious infections in immunocompromised patients, expresses high-affinity iron acquisition functions needed for growth under iron-limiting laboratory conditions. In this study, we determined that the initial interaction of the ATCC 19606T type strain with A549 human alveolar epithelial cells is independent of the production of BasD and BauA, proteins needed for acinetobactin biosynthesis and transport, respectively. In contrast, these proteins are required for this strain to persist within epithelial cells and cause their apoptotic death. Infection assays using Galleria mellonella larvae showed that impairment of acinetobactin biosynthesis and transport functions significantly reduces the ability of ATCC 19606T cells to persist and kill this host, a defect that was corrected by adding inorganic iron to the inocula. The results obtained with these ex vivo and in vivo approaches were validated using a mouse sepsis model, which showed that expression of the acinetobactin-mediated iron acquisition system is critical for ATCC 19606T to establish an infection and kill this vertebrate host. These observations demonstrate that the virulence of the ATCC 19606T strain depends on the expression of a fully active acinetobactin-mediated system. Interestingly, the three models also showed that impairment of BasD production results in an intermediate virulence phenotype compared to those of the parental strain and the BauA mutant. This observation suggests that acinetobactin intermediates or precursors play a virulence role, although their contribution to iron acquisition is less relevant than that of mature acinetobactin. PMID:22232188

  13. Response to Bile Salts in Clinical Strains of Acinetobacter baumannii Lacking the AdeABC Efflux Pump: Virulence Associated with Quorum Sensing

    PubMed Central

    López, Maria; Blasco, Lucia; Gato, Eva; Perez, Astrid; Fernández-Garcia, Laura; Martínez-Martinez, Luis; Fernández-Cuenca, Felipe; Rodríguez-Baño, Jesús; Pascual, Alvaro; Bou, German; Tomás, Maria

    2017-01-01

    Introduction: Acinetobacter baumannii is an opportunistic nosocomial pathogen associated with multiple infections. This pathogen usually colonizes (first stage of microbial infection) host tissues that are in contact with the external environment. As one of the sites of entry in human hosts is the gastrointestinal tract, the pathogen must be capable of tolerating bile salts. However, studies analyzing the molecular characteristics involved in the response to bile salts in clinical strains of A. baumannii are scarce. Material and Methods: Microbiological and transcriptional studies (arrays and RT-PCR) in the response to bile salts were carried out in isogenic (A. baumanni ΔadeB ATCC 17978 and A. baumannii ΔadeL ATCC 17978) and clinical strains from clone ST79/PFGE-HUI-1 which is characterized by lacking the AdeABC efflux pump and by overexpression the AdeFGH efflux pump. Results and Discussion: In presence of bile salts, in addition to the glutamate/aspartate transporter were found overexpressed in A. baumannii ΔadeB ATCC 17978, the virulence factors (surface motility, biofilm, and Type VI Secretion System) which are associated with activation of the Quorum Sensing system. Overexpression of these factors was confirmed in clinical strains of clone ST79/PFGE-HUI-1. Conclusions: This the first study about the adaptive response to bile salts investigating the molecular and microbiological characteristics in response to bile salts of an isogenic model of A. baumannii ATCC 17978 and clinical isolates of A. baumannii (clinical strains of ST79/PFGE-HUI-1) lacking the main RND efflux pump (AdeABC). Clinical isolates of A. baumannii lacking the AdeABC efflux pump (clone ST79/PFGE-HUI-1) displayed a new clinical profile (increased invasiveness) possibly associated with the response to stress conditions (such as the presence of bile salts). PMID:28536672

  14. Evaluation of matrix-assisted laser desorption ionization-time of flight mass spectrometry for species identification of Acinetobacter strains isolated from blood cultures.

    PubMed

    Kishii, K; Kikuchi, K; Matsuda, N; Yoshida, A; Okuzumi, K; Uetera, Y; Yasuhara, H; Moriya, K

    2014-05-01

    The clinical relevance of Acinetobacter species, other than A. baumannii, as human pathogens has not been sufficiently assessed owing to the insufficiency of simple phenotypic clinical diagnostic laboratory tests. Infections caused by these organisms have different impacts on clinical outcome and require different treatment and management approaches. It is therefore important to correctly identify Acinetobacter species. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been introduced to identify a wide range of microorganisms in clinical laboratories, but only a few studies have examined its utility for identifying Acinetobacter species, particularly those of the non-Acinetobacter baumannii complex. We therefore evaluated MALDI-TOF MS for identification of Acinetobacter species by comparing it with sequence analysis of rpoB using 123 isolates of Acinetobacter species from blood. Of the isolates examined, we identified 106/123 (86.2%) to species, and 16/123 (13.0%) could only be identified as acinetobacters. The identity of one isolate could not be established. Of the 106 species identified, 89/106 (84.0%) were confirmed by rpoB sequence analysis, and 17/106 (16.0%) were discordant. These data indicate correct identification of 89/123 (72.4%) isolates. Surprisingly, all blood culture isolates were identified as 13 species of Acinetobacter, and the incidence of Acinetobacter pittii was unexpectedly high (42/123; 34.1%) and exceeded that of A. baumannii (22/123; 17.9%). Although the present identification rate using MALDI-TOF MS is not acceptable for species-level identification of Acinetobacter, further expansion of the database should remedy this situation.

  15. Rapid identification of Acinetobacter baumannii, Acinetobacter nosocomialis and Acinetobacter pittii with a multiplex PCR assay.

    PubMed

    Chen, Te-Li; Lee, Yi-Tzu; Kuo, Shu-Chen; Yang, Su-Pen; Fung, Chang-Phone; Lee, Shou-Dong

    2014-09-01

    Acinetobacter baumannii, Acinetobacter nosocomialis and Acinetobacter pittii are clinically relevant members of the Acinetobacter calcoaceticus-A. baumannii (Acb) complex and important nosocomial pathogens. These three species are genetically closely related and phenotypically similar; however, they differ in their epidemiology, antibiotic resistance and pathogenicity. In this study, we investigated the use of a multiplex PCR-based assay designed to detect internal fragments of the 16S-23S rRNA intergenic region and the gyrB and recA genes. The assay was capable of differentiating A. baumannii, A. nosocomialis and A. pittii in a reliable manner. In 23 different reference strains and 89 clinical isolates of Acinetobacter species, the assay accurately identified clinically relevant Acb complex species except those 'between 1 and 3' or 'close to 13TU'. None of the non-Acb complex species was misidentified. In an analysis of 1034 positive blood cultures, the assay had a sensitivity of 92.4 % and specificity of 98.2 % for Acb complex identification. Our results show that a single multiplex PCR assay can reliably differentiate clinically relevant Acb complex species. Thus, this method may be used to better understand the clinical differences between infections caused by these species.

  16. Analysis of the role of the LH92_11085 gene of a biofilm hyper-producing Acinetobacter baumannii strain on biofilm formation and attachment to eukaryotic cells

    PubMed Central

    Álvarez-Fraga, Laura; Pérez, Astrid; Rumbo-Feal, Soraya; Merino, María; Vallejo, Juan Andrés; Ohneck, Emily J.; Edelmann, Richard E.; Beceiro, Alejandro; Vázquez-Ucha, Juan C.; Valle, Jaione; Actis, Luis A.; Bou, Germán; Poza, Margarita

    2016-01-01

    ABSTRACT Acinetobacter baumannii is a nosocomial pathogen that has a considerable ability to survive in the hospital environment partly due to its capacity to form biofilms. The first step in the process of establishing an infection is adherence of the bacteria to target cells. Chaperone-usher pili assembly systems are involved in pilus biogenesis pathways that play an important role in adhesion to host cells and tissues as well as medically relevant surfaces. After screening a collection of strains, a biofilm hyper-producing A. baumannii strain (MAR002) was selected to describe potential targets involved in pathogenicity. MAR002 showed a remarkable ability to form biofilm and attach to A549 human alveolar epithelial cells. Analysis of MAR002 using transmission electron microscopy (TEM) showed a significant presence of pili on the bacterial surface. Putative protein-coding genes involved in pili formation were identified based on the newly sequenced genome of MAR002 strain (JRHB01000001/2 or NZ_JRHB01000001/2). As assessed by qRT-PCR, the gene LH92_11085, belonging to the operon LH92_11070-11085, is overexpressed (ca. 25-fold more) in biofilm-associated cells compared to exponential planktonic cells. In the present work we investigate the role of this gene on the MAR002 biofilm phenotype. Scanning electron microscopy (SEM) and biofilm assays showed that inactivation of LH92_11085 gene significantly reduced bacterial attachment to A549 cells and biofilm formation on plastic, respectively. TEM analysis of the LH92_11085 mutant showed the absence of long pili formations normally present in the wild-type. These observations indicate the potential role this LH92_11085 gene could play in the pathobiology of A baumannii. PMID:26854744

  17. Whole-Genome Sequence of a European Clone II and OXA-72-Producing Acinetobacter baumannii Strain from Serbia

    PubMed Central

    Girlich, Delphine; Imanci, Dilek; Bernabeu, Sandrine; Fortineau, Nicolas

    2015-01-01

    We report here the draft genome sequence of a carbapenem-resistant Acinetobacter baumannii strain isolated from a patient, a strain which previously stayed in Serbia. This isolate possessed the blaOXA-72 carbapenemase gene. The draft genome sequence consists of a total length of 3.91 Mbp, with an average G+C content of 38.8%. PMID:26659671

  18. Emulsifier formation with Acinetobacter: search for an excretion-reduced mutant of Acinetobacter calcoaceticus 69-V.

    PubMed

    Müller, R H; Babel, W

    1986-01-01

    After growth on acetate three groups of Acinetobacter strains could be identified with respect to the excretion of a bioemulsifier. Mutants of A. calcoaceticus 69-V were selected which produced reduced amounts of emulsifier.

  19. In vitro synergistic antibacterial activity of the essential oil from Zingiber cassumunar Roxb against extensively drug-resistant Acinetobacter baumannii strains.

    PubMed

    Boonyanugomol, Wongwarut; Kraisriwattana, Kairin; Rukseree, Kamolchanok; Boonsam, Kraisorn; Narachai, Panchaporn

    In this study, we determined the antibacterial and synergistic activities of the essential oil from Zingiber cassumunar against the extensively drug-resistant (XDR) Acinetobacter baumannii strains. The antibacterial and synergistic properties of the essential oil from Z. cassumunar were examined by agar disc diffusion tests. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated by broth microdilution using the resazurin assay. The in vitro time-kill antibacterial kinetics was analyzed using the plate count technique. We found that the essential oil from Z. cassumunar had antibacterial activity against A. baumannii, with MIC and MBC ranging from 7.00 to 9.24mg/ml. The essential oil could completely inhibit A. baumannii at 1h, and coccoid-shaped bacteria were found after treatment. In addition, the essential oil had a synergistic effect when combined with antibiotics, e.g., aminoglycosides, fluoroquinolones, tetracyclines, and folate pathway inhibitors. Thus, the essential oil from Z. cassumunar has strong antibacterial and synergistic activities against XDR A. baumannii, which may provide the basis for the development of a new therapy against drug-resistant bacteria. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  20. Complete genome sequence of hypervirulent and outbreak-associated Acinetobacter baumannii strain LAC-4: epidemiology, resistance genetic determinants and potential virulence factors

    PubMed Central

    Ou, Hong-Yu; Kuang, Shan N.; He, Xinyi; Molgora, Brenda M.; Ewing, Peter J.; Deng, Zixin; Osby, Melanie; Chen, Wangxue; Xu, H. Howard

    2015-01-01

    Acinetobacter baumannii is an important human pathogen due to its multi-drug resistance. In this study, the genome of an ST10 outbreak A. baumannii isolate LAC-4 was completely sequenced to better understand its epidemiology, antibiotic resistance genetic determinants and potential virulence factors. Compared with 20 other complete genomes of A. baumannii, LAC-4 genome harbors at least 12 copies of five distinct insertion sequences. It contains 12 and 14 copies of two novel IS elements, ISAba25 and ISAba26, respectively. Additionally, three novel composite transposons were identified: Tn6250, Tn6251 and Tn6252, two of which contain resistance genes. The antibiotic resistance genetic determinants on the LAC-4 genome correlate well with observed antimicrobial susceptibility patterns. Moreover, twelve genomic islands (GI) were identified in LAC-4 genome. Among them, the 33.4-kb GI12 contains a large number of genes which constitute the K (capsule) locus. LAC-4 harbors several unique putative virulence factor loci. Furthermore, LAC-4 and all 19 other outbreak isolates were found to harbor a heme oxygenase gene (hemO)-containing gene cluster. The sequencing of the first complete genome of an ST10 A. baumannii clinical strain should accelerate our understanding of the epidemiology, mechanisms of resistance and virulence of A. baumannii. PMID:25728466

  1. Multidrug-resistant Acinetobacter baumannii strains carrying the bla(OxA-23) and the bla(GES-11) genes in a neonatology center in Tunisia.

    PubMed

    Charfi-Kessis, Karama; Mansour, Wejdene; Ben Haj Khalifa, Anis; Mastouri, Maha; Nordmann, Patrice; Aouni, Mahjoub; Poirel, Laurent

    2014-09-01

    Multidrug-resistant and difficult-to-treat Acinetobacter baumannii may be responsible for nosocomial infections. The production of carbapenem-hydrolyzing class D β-lactamases (CHDLs) and extended-spectrum β-lactamase (ESBLs) of the GES type possessing a carbapenemase activity has been increasingly reported worldwide in A. baumannii. The aim of this study was to analyze the resistance mechanisms of two carbapenem resistant A. baumannii clinical isolates recovered in a neonatology center in the center-east of Tunisia. Two carbapenem resistant A. baumannii isolates were recovered. The first isolate co-harbored the blaGES-11 ESBL gene and the blaOxA-23 CHDL gene. Analyses of the genetic location indicated that the blaGES-11 gene was plasmid located (Gr6). However, the blaOxA-23 gene was located on the chromosome. The second strain had only the blaOxA-23 CHDL gene, which was plasmid located. This study showed the first description of the GES-type β-lactamase in A. baumannii in Tunisia.

  2. Phenotypic and genotypic characterization of Vagococcus fluvialis, including strains isolated from human sources.

    PubMed Central

    Teixeira, L M; Carvalho, M G; Merquior, V L; Steigerwalt, A G; Brenner, D J; Facklam, R R

    1997-01-01

    This study presents phenotypic and genotypic data for seven isolates of Vagococcus fluvialis, including four strains recovered from human clinical sources, one strain isolated from an environmental source, and two strains isolated from pigs. On the basis of phenotypic characteristics, most isolates were initially classified as "unidentified enterococci," because they resembled atypical arginine-negative enterococcal species. All seven strains as well as the type strain of V. fluvialis reacted with the AccuProbe Enterococcus genetic probe. The seven isolates had virtually indistinguishable whole-cell protein profiles that were similar to that of the V. fluvialis type strain and distinct from those of Enterococcus and Lactococcus species. DNA-DNA reassociation experiments confirmed that the strains were V. fluvialis. They were 71% or more related to the V. fluvialis type strain under optimum and stringent conditions, with 2.5% or less divergence within related sequences. All strains were susceptible to ampicillin, cefotaxime, trimethoprim-sulfamethoxazole, and vancomycin and were resistant to clindamycin, lomefloxacin, and ofloxacin. Strain-to-strain variation was observed in relation to susceptibilities to 18 other antimicrobial agents. Chromosomal DNA was analyzed by pulsed-field gel electrophoresis (PFGE) after digestion with SmaI. Distinctive PFGE patterns were generated, suggesting the nonclonal nature of V. fluvialis strains. Although the number of strains was small, this report provides molecular characterization of V. fluvialis and the first evidence of a possible connection of this species with human infections. PMID:9350732

  3. Acinetobacter variabilis sp. nov. (formerly DNA group 15 sensu Tjernberg & Ursing), isolated from humans and animals.

    PubMed

    Krizova, Lenka; McGinnis, Jana; Maixnerova, Martina; Nemec, Matej; Poirel, Laurent; Mingle, Lisa; Sedo, Ondrej; Wolfgang, William; Nemec, Alexandr

    2015-03-01

    We aimed to define the taxonomic status of 16 strains which were phenetically congruent with Acinetobacter DNA group 15 described by Tjernberg & Ursing in 1989. The strains were isolated from a variety of human and animal specimens in geographically distant places over the last three decades. Taxonomic analysis was based on an Acinetobacter-targeted, genus-wide approach that included the comparative sequence analysis of housekeeping, protein-coding genes, whole-cell profiling based on matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS), an array of in-house physiological and metabolic tests, and whole-genome comparative analysis. Based on analyses of the rpoB and gyrB genes, the 16 strains formed respective, strongly supported clusters clearly separated from the other species of the genus Acinetobacter. The distinctness of the group at the species level was indicated by average nucleotide identity values of ≤82 % between the whole genome sequences of two of the 16 strains (NIPH 2171(T) and NIPH 899) and those of the known species. In addition, the coherence of the group was also supported by MALDI-TOF MS. All 16 strains were non-haemolytic and non-gelatinase-producing, grown at 41 °C and utilized a rather limited number of carbon sources. Virtually every strain displayed a unique combination of metabolic and physiological features. We conclude that the 16 strains represent a distinct species of the genus Acinetobacter, for which the name Acinetobacter variabilis sp. nov. is proposed to reflect its marked phenotypic heterogeneity. The type strain is NIPH 2171(T) ( = CIP 110486(T) = CCUG 26390(T) = CCM 8555(T)).

  4. Acinetobacter infection--an emerging threat to human health.

    PubMed

    Visca, Paolo; Seifert, Harald; Towner, Kevin J

    2011-12-01

    The genus Acinetobacter comprises a complex and heterogeneous group of bacteria, many of which are capable of causing a range of opportunistic, often catheter-related, infections in humans. However, Acinetobacter baumannii, as well as its close relatives belonging to genomic species 3 ("Acinetobacter pittii") and 13TU ("Acinetobacter nosocomialis"), are important nosocomial pathogens, often associated with epidemic outbreaks of infection, that are only rarely found outside of a clinical setting. These organisms are frequently pandrug-resistant and are capable of causing substantial morbidity and mortality in patients with severe underlying disease, both in the hospital and in the community. Several epidemic clonal lineages of A. baumannii have disseminated worldwide and seem to have a selective advantage over non-epidemic strains. The reasons for the success of these epidemic lineages remain to be elucidated, but could be related to the potential of these organisms to achieve very dynamic reorganization and rapid evolution of their genome, including the acquisition and expression of additional antibiotic resistance determinants, under fluctuating environmental and selective conditions.

  5. Comparative Phosphoproteomics Reveals the Role of AmpC β-lactamase Phosphorylation in the Clinical Imipenem-resistant Strain Acinetobacter baumannii SK17*

    PubMed Central

    Lai, Juo-Hsin; Yang, Jhih-Tian; Chern, Jeffy; Chen, Te-Li; Wu, Wan-Ling; Liao, Jiahn-Haur; Tsai, Shih-Feng; Liang, Suh-Yuen; Chou, Chi-Chi

    2016-01-01

    Nosocomial infectious outbreaks caused by multidrug-resistant Acinetobacter baumannii have emerged as a serious threat to human health. Phosphoproteomics of pathogenic bacteria has been used to identify the mechanisms of bacterial virulence and antimicrobial resistance. In this study, we used a shotgun strategy combined with high-accuracy mass spectrometry to analyze the phosphoproteomics of the imipenem-susceptible strain SK17-S and -resistant strain SK17-R. We identified 410 phosphosites on 248 unique phosphoproteins in SK17-S and 285 phosphosites on 211 unique phosphoproteins in SK17-R. The distributions of the Ser/Thr/Tyr/Asp/His phosphosites in SK17-S and SK17-R were 47.0%/27.6%/12.4%/8.0%/4.9% versus 41.4%/29.5%/17.5%/6.7%/4.9%, respectively. The Ser-90 phosphosite, located on the catalytic motif S88VS90K of the AmpC β-lactamase, was first identified in SK17-S. Based on site-directed mutagenesis, the nonphosphorylatable mutant S90A was found to be more resistant to imipenem, whereas the phosphorylation-simulated mutant S90D was sensitive to imipenem. Additionally, the S90A mutant protein exhibited higher β-lactamase activity and conferred greater bacterial protection against imipenem in SK17-S compared with the wild-type. In sum, our results revealed that in A. baumannii, Ser-90 phosphorylation of AmpC negatively regulates both β-lactamase activity and the ability to counteract the antibiotic effects of imipenem. These findings highlight the impact of phosphorylation-mediated regulation in antibiotic-resistant bacteria on future drug design and new therapies. PMID:26499836

  6. The Effect of Ivermectin in Seven Strains of Aedes aegypti (Diptera: Culicidae) Including a Genetically Diverse Laboratory Strain and Three Permethrin Resistant Strains

    PubMed Central

    Deus, K. M.; Saavedra-rodriguez, K.; Butters, M. P.; Black, W. C.; Foy, B. D.

    2014-01-01

    Seven different strains of Aedes aegypti (L.), including a genetically diverse laboratory strain, three laboratory-selected permethrin-resistant strains, a standard reference strain, and two recently colonized strains were fed on human blood containing various concentrations of ivermectin. Ivermectin reduced adult survival, fecundity, and hatch rate of eggs laid by ivermectin-treated adults in all seven strains. The LC50 of ivermectin for adults and the concentration that prevented 50% of eggs from hatching was calculated for all strains. Considerable variation in adult survival after an ivermectin-bloodmeal occurred among strains, and all three permethrin-resistant strains were significantly less susceptible to ivermectin than the standard reference strain. The hatch rate after an ivermectin bloodmeal was less variable among strains, and only one of the permethrin-resistant strains differed significantly from the standard reference strain. Our studies suggest that ivermectin induces adult mortality and decreases the hatch rate of eggs through different mechanisms. A correlation analysis of log-transformed LC50 among strains suggests that permethrin and ivermectin cross-resistance may occur. PMID:22493855

  7. Outbreak of multidrug-resistant Acinetobacter baumannii in an intensive care unit.

    PubMed

    Dettori, Marco; Piana, Andrea; Deriu, Maria Grazia; Lo Curto, Paola; Cossu, Andrea; Musumeci, Rosario; Cocuzza, Clementina; Astone, Vito; Contu, Maria Antonietta; Sotgiu, Giovanni

    2014-04-01

    Acinetobacter baumannii is a ubiquitous microrganism often able to colonize and survive in different environments. Currently it is one of the most common pathogens responsible for nosocomial infections, including outbreaks, especially in long-term care facilities. The aim of this study was to show the results of an environmental investigation and genotyping analysis of multidrug-resistant Acinetobacter baumannii associated with an outbreak in an intensive care unit of a tertiary hospital located in Northern Sardinia, Italy. Positive cultures of MDR Acinetobacter baumannii were reported during the month of June 2012, after the collection of biological samples from ten patients. Acinetobacter baumannii was isolated during the following environmental investigation from the headboard of two beds. All the strains were genotyped by performing multiplex PCR to identify the presence of genes encoding carbapenemases. The results showed specific bands of bla(OXA-51-like) gene and of the bla(OXA-23-like) gene. PFGE highlighted minimal differences in genomic fingerprints, while the cluster analysis grouped the isolated microorganisms into two closely related clusters, characterized by Dice's similarity coefficient equal to 95.1%. MLST showed that the strains belonged to ST31. The results of the study highlight the need, especially in high-risk areas, to adopt strict hygiene practices, particularly hand hygiene, and to ensure an appropriate turnover of personal protective equipment, which could be responsible for the spread of biological agents, such as MDR Acinetobacter baumannii.

  8. Acquisition of a High Diversity of Bacteria during the Hajj Pilgrimage, Including Acinetobacter baumannii with blaOXA-72 and Escherichia coli with blaNDM-5 Carbapenemase Genes

    PubMed Central

    Leangapichart, Thongpan; Gautret, Philippe; Belhouchat, Khadidja; Memish, Ziad; Raoult, Didier

    2016-01-01

    Pilgrims returning from the Hajj (pilgrimage to Mecca) can be carriers of multidrug-resistant bacteria (MDR). Pharyngeal and rectal swab samples were collected from 98 pilgrims before and after they traveled to the Hajj in 2014 to investigate the acquisition of MDR bacteria. The bacterial diversity in pharyngeal swab samples was assessed by culture with selective media. There was a significantly higher diversity of bacteria in samples collected after the return from the Hajj than in those collected before (P = 0.0008). Surprisingly, Acinetobacter baumannii strains were isolated from 16 pharyngeal swab samples (1 sample taken during the Hajj and 15 samples taken upon return) and 26 post-Hajj rectal swab samples, while none were isolated from samples taken before the Hajj. Testing of all samples by real-time PCR targeting blaOXA-51 gave positive results for only 1% of samples taken during the Hajj, 21/90 (23.3%) pharyngeal swab samples taken post-Hajj, and 35/90 (38.9%) rectal swab samples taken post-Hajj. One strain of A. baumannii isolated from the pharynx was resistant to imipenem and harbored a blaOXA-72 carbapenemase gene. Multilocus sequence typing analysis of 43 A. baumannii isolates revealed a huge diversity of 35 sequence types (STs), among which 18 were novel STs reported for the first time in this study. Moreover, we also found one Escherichia coli isolate, collected from a rectal swab sample from a pilgrim taken after the Hajj, which harbored blaNDM-5, blaCTX-M-15, blaTEM-1, and aadA2 (ST2659 and ST181). In conclusion, pilgrims are at a potential risk of acquiring and transmitting MDR Acinetobacter spp. and carbapenemase-producing Gram-negative bacteria during the Hajj season. PMID:27458222

  9. Improvement of MALDI-TOF MS profiling for the differentiation of species within the Acinetobacter calcoaceticus-Acinetobacter baumannii complex.

    PubMed

    Šedo, Ondrej; Nemec, Alexandr; Křížová, Lenka; Kačalová, Magdaléna; Zdráhal, Zbyněk

    2013-12-01

    MALDI-TOF MS is currently becoming the method of choice for rapid identification of bacterial species in routine diagnostics. Yet, this method suffers from the inability to differentiate reliably between some closely related bacterial species including those of the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex, namely A. baumannii and Acinetobacter nosocomialis. In the present study, we evaluated a protocol which was different from that used in the Bruker Daltonics identification system (MALDI BioTyper) to improve species identification using a taxonomically precisely defined set of 105 strains representing the four validly named species of the ACB complex. The novel protocol is based on the change in matrix composition from alpha-cyano-4-hydroxycinnamic acid (saturated solution in water:acetonitrile:trifluoroacetic acid, 47.5:50:2.5, v/v) to ferulic acid (12.5mgml(-1) solution in water:acetonitrile:formic acid 50:33:17, v/v), while the other steps of sample processing remain unchanged. Compared to the standard protocol, the novel one extended the range of detected compounds towards higher molecular weight, produced signals with better mass resolution, and allowed the detection of species-specific signals. As a result, differentiation of A. nosocomialis and A. baumannii strains by cluster analysis was improved and 13 A. nosocomialis strains, assigned erroneously or ambiguously by using the standard protocol, were correctly identified.

  10. A review of intravenous minocycline for treatment of multidrug-resistant Acinetobacter infections.

    PubMed

    Ritchie, David J; Garavaglia-Wilson, Alexandria

    2014-12-01

    Options for treatment of multidrug-resistant (MDR) Acinetobacter baumannii infections are extremely limited. Minocycline intravenous is active against many MDR strains of Acinetobacter, and Clinical and Laboratory Standards Institute breakpoints exist to guide interpretation of minocycline susceptibility results with Acinetobacter. In addition, minocycline intravenous holds a US Food and Drug Administration indication for treatment of infections caused by Acinetobacter. There is an accumulating amount of literature reporting successful use of minocycline intravenous for treatment of serious MDR Acinetobacter infections, particularly for nosocomial pneumonia. These results, coupled with the generally favorable tolerability of minocycline intravenous, support its use as a viable therapeutic option for treatment of MDR Acinetobacter infections.

  11. Utilization of n-alkanes by a newly isolated strain of Acinetobacter venetianus: the role of two AlkB-type alkane hydroxylases.

    PubMed

    Throne-Holst, Mimmi; Markussen, Sidsel; Winnberg, Asgeir; Ellingsen, Trond E; Kotlar, Hans-Kristian; Zotchev, Sergey B

    2006-09-01

    A bacterial strain capable of utilizing n-alkanes with chain lengths ranging from decane (C10H22) to tetracontane (C40H82) as a sole carbon source was isolated using a system for screening microorganisms able to grow on paraffin (mixed long-chain n-alkanes). The isolate, identified according to its 16S rRNA sequence as Acinetobacter venetianus, was designated A. venetianus 6A2. Two DNA fragments encoding parts of AlkB-type alkane hydroxylase homologues, designated alkMa and alkMb, were polymerase chain reaction-amplified from the genome of A. venetianus 6A2. To study the roles of these two alkM paralogues in n-alkane utilization in A. venetianus 6A2, we constructed alkMa, alkMb, and alkMa/alkMb disruption mutants. Studies on the growth patterns of the disruption mutants using n-alkanes with different chain lengths as sole carbon source demonstrated central roles for the alkMa and alkMb genes in utilization of C10 to C18 n-alkanes. Comparative analysis of these patterns also suggested different substrate preferences for AlkMa and AlkMb in n-alkane utilization. Because both single and double mutants were able to grow on n-alkanes with chain lengths of C20 and longer, we concluded that yet another enzyme(s) for the utilization of these n-alkanes must exist in A. venetianus 6A2.

  12. The Secrets of Acinetobacter Secretion.

    PubMed

    Weber, Brent S; Kinsella, Rachel L; Harding, Christian M; Feldman, Mario F

    2017-02-16

    Infections caused by the bacterial pathogen Acinetobacter baumannii are a mounting concern for healthcare practitioners as widespread antibiotic resistance continues to limit therapeutic treatment options. The biological processes used by A. baumannii to cause disease are not well defined, but recent research has indicated that secreted proteins may play a major role. A variety of mechanisms have now been shown to contribute to protein secretion by A. baumannii and other pathogenic species of Acinetobacter, including a type II secretion system (T2SS), a type VI secretion system (T6SS), autotransporter, and outer membrane vesicles (OMVs). In this review, we summarize the current knowledge of secretion systems in Acinetobacter species, and highlight their unique aspects that contribute to the pathogenicity and persistence of these emerging pathogens.

  13. Multidrug resistant Acinetobacter baumannii: a descriptive study in a city hospital

    PubMed Central

    2010-01-01

    Background Multidrug resistant Acinetobacter baumannii, (MRAB) is an important cause of hospital acquired infection. The purpose of this study is to determine the risk factors for MRAB in a city hospital patient population. Methods This study is a retrospective review of a city hospital epidemiology data base and includes 247 isolates of Acinetobacter baumannii (AB) from 164 patients. Multidrug resistant Acinetobacter baumannii was defined as resistance to more than three classes of antibiotics. Using the non-MRAB isolates as the control group, the risk factors for the acquisition of MRAB were determined. Results Of the 247 AB isolates 72% (177) were multidrug resistant. Fifty-eight percent (143/247) of isolates were highly resistant (resistant to imipenem, amikacin, and ampicillin-sulbactam). Of the 37 patients who died with Acinetobacter colonization/infection, 32 (86%) patients had the organism recovered from the respiratory tract. The factors which were found to be significantly associated (p ≤ 0.05) with multidrug resistance include the recovery of AB from multiple sites, mechanical ventilation, previous antibiotic exposure, and the presence of neurologic impairment. Multidrug resistant Acinetobacter was associated with significant mortality when compared with sensitive strains (p ≤ 0.01). When surgical patients (N = 75) were considered separately, mechanical ventilation and multiple isolates remained the factors significantly associated with the development of multidrug resistant Acinetobacter. Among surgical patients 46/75 (61%) grew a multidrug resistant strain of AB and 37/75 (40%) were resistant to all commonly used antibiotics including aminoglycosides, cephalosporins, carbepenems, extended spectrum penicillins, and quinolones. Thirty-five percent of the surgical patients had AB cultured from multiple sites and 57% of the Acinetobacter isolates were associated with a co-infecting organism, usually a Staphylococcus or Pseudomonas. As in medical

  14. CraA, a Major Facilitator Superfamily Efflux Pump Associated with Chloramphenicol Resistance in Acinetobacter baumannii▿

    PubMed Central

    Roca, I.; Marti, S.; Espinal, P.; Martínez, P.; Gibert, I.; Vila, J.

    2009-01-01

    Acinetobacter baumannii has been increasingly associated with hospital-acquired infections, and the presence of multidrug resistance strains is of great concern to clinicians. A. baumannii is thought to possess a great deal of intrinsic resistance to several antimicrobial agents, including chloramphenicol, although the mechanisms involved in such resistance are not well understood. In this work, we have identified a major facilitator superfamily efflux pump present in most A. baumannii strains, displaying strong substrate specificity toward chloramphenicol. PMID:19581458

  15. Short communication: Genetic characterization of antimicrobial resistance in Acinetobacter isolates recovered from bulk tank milk.

    PubMed

    Tamang, M D; Gurung, M; Nam, H M; Kim, S R; Jang, G C; Jung, S C; Lim, S K

    2014-02-01

    A total of 176 Acinetobacter isolates, including 57 Acinetobacter baumannii originally obtained from 2,287 bulk tank milk (BTM) samples in Korea was investigated for the genetic basis of antimicrobial resistance using molecular methods. In addition, the occurrence and cassette content of integrons were examined and the genetic diversity of A. baumannii strains identified was evaluated. Aminoglycoside-modifying enzyme genes were detected in 15 (88.2%) of the 17 aminoglycoside-resistant Acinetobacter isolates tested. The most common aminoglycoside-modifying enzyme gene identified was adenylyltransferase gene aadB (n = 9), followed by phosphotransferase genes aphA6 (n = 7) and aphA1 (n = 5). Of the 31 isolates resistant to tetracycline, tet(39) was detected in 20 of them. The genetic basis of resistance to sulfonamide was identified in 15 (53.6%) of 28 trimethoprim-sulfamethoxazole-resistant isolates and 9 (32.1%) of them carried both sul1 and sul2 genes. A blaADC-7-like gene was detected in 1 β-lactam-resistant A. baumannii. Furthermore, class 1 integron was identified in 11 Acinetobacter isolates. Two gene cassettes dfrA15, conferring resistance to trimethoprim, and aadA2, conferring resistance to aminoglycosides, were identified in 8 Acinetobacter isolates. None of the isolates was positive for class 2 or class 3 integrons. Pulsed-field gel electrophoresis revealed that most of the A. baumannii strains from BTM samples were genetically diverse, indicating that the occurrence of A. baumannii strains in BTM was not the result of dissemination of a single clone. Elucidation of resistance mechanisms associated with the resistance phenotype and a better understanding of resistance genes may help in the development of strategies to control infections, such as mastitis, and to prevent further dissemination of antibiotic resistance genes. To the best of our knowledge, this is the first report of molecular characterization of antimicrobial-resistant Acinetobacter spp. from

  16. Characterization of the chromosomal cephalosporinases produced by Acinetobacter lwoffii and Acinetobacter baumannii clinical isolates.

    PubMed Central

    Perilli, M; Felici, A; Oratore, A; Cornaglia, G; Bonfiglio, G; Rossolini, G M; Amicosante, G

    1996-01-01

    The beta-lactamases produced by Acinetobacter lwoffii ULA-501, Acinetobacter baumannii ULA-187, and A. baumannii AC-14 strains were purified and characterized, and their kinetic interactions with several beta-lactam molecules, including substrates and inhibitors, were studied in detail. The three enzymes appeared to be cephalosporinases with different acylation efficiencies (kcat/Km ratio values), and their hydrolytic activities were inhibited by benzylpenicillin, piperacillin, and cefotaxime, which did not behave as substrates. Carbenicillin was a substrate for the beta-lactamase from A. lwoffii ULA-501, whereas it acted as a transient inactivator of the enzymes produced by the two A. baumannii strains. Clavulanic acid was unable to inactivate the three beta-lactamases, whereas sulbactam behaved as an inactivator only at a high concentration (1 mM) which is difficult to achieve during antibiotic therapy. Analysis of the interaction with 6-beta-iodopenicillanic acid also allowed us to better discriminate the three beta-lactamases analyzed in the present study, which can be included in the group 1 functional class (5). PMID:8851599

  17. Acinetobacter species as model microorganisms in environmental microbiology: current state and perspectives.

    PubMed

    Jung, Jaejoon; Park, Woojun

    2015-03-01

    Acinetobacter occupies an important position in nature because of its ubiquitous presence in diverse environments such as soils, fresh water, oceans, sediments, and contaminated sites. Versatile metabolic characteristics allow species of this genus to catabolize a wide range of natural compounds, implying active participation in the nutrient cycle in the ecosystem. On the other hand, multi-drug-resistant Acinetobacter baumannii causing nosocomial infections with high mortality has been raising serious concerns in medicine. Due to the ecological and clinical importance of the genus, Acinetobacter was proposed as a model microorganism for environmental microbiological studies, pathogenicity tests, and industrial production of chemicals. For these reasons, Acinetobacter has attracted significant attention in scientific and biotechnological fields, but only limited research areas such as natural transformation and aromatic compound degradation have been intensively investigated, while important physiological characteristics including quorum sensing, motility, and stress response have been neglected. The aim of this review is to summarize the recent achievements in Acinetobacter research with a special focus on strain DR1 and to compare the similarities and differences between species or other genera. Research areas that require more attention in future research are also suggested.

  18. Draft Genome Sequence of Acinetobacter baumannii Strain ABBL099, a Multidrug-Resistant Clinical Outbreak Isolate with a Novel Multilocus Sequence Type

    PubMed Central

    Fitzpatrick, Margaret A.; Hauser, Alan R.

    2014-01-01

    Acinetobacter baumannii is associated with hospital-acquired infections and can cause persistent outbreaks. Here we report the draft genome sequence of ABBL099, a multidrug-resistant clinical isolate of A. baumannii belonging to a novel sequence type and representative of clonal isolates cultured from patients at one institution over a 4-year time period. PMID:25212612

  19. Genotypic and Phenotypic Correlations of Multidrug-Resistant Acinetobacter baumannii-A. calcoaceticus Complex Strains Isolated from Patients at the National Naval Medical Center

    USDA-ARS?s Scientific Manuscript database

    Acinetobacter baumannii-calcoaceticus complex (ABC) infections have complicated the care of U.S. combat casualties. In this study, 102 ABC isolates from wounded soldiers treated at National Naval Medical Center (NNMC) were characterized by phenotype and genotype to identify clones in this population...

  20. High frequency of Acinetobacter soli among Acinetobacter isolates causing bacteremia at a tertiary hospital in Japan.

    PubMed

    Endo, Shiro; Yano, Hisakazu; Kanamori, Hajime; Inomata, Shinya; Aoyagi, Tetsuji; Hatta, Masumitsu; Gu, Yoshiaki; Tokuda, Koichi; Kitagawa, Miho; Kaku, Mitsuo

    2014-03-01

    Acinetobacter baumannii is generally the most frequently isolated Acinetobacter species. Sequence analysis techniques allow reliable identification of Acinetobacter isolates at the species level. Forty-eight clinical isolates of Acinetobacter spp. were obtained from blood cultures at Tohoku University Hospital. These isolates were identified at the species level by partial sequencing of the RNA polymerase β-subunit (rpoB), 16S rRNA, and gyrB genes. Then further characterization was done by using the PCR for detection of OXA-type β-lactamase gene clusters, metallo-β-lactamases, and carO genes. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing were also performed. The most frequent isolate was Acinetobacter soli (27.1%). Six of the 13 A. soli isolates were carbapenem nonsusceptible, and all of these isolates produced IMP-1. PFGE revealed that the 13 A. soli isolates were divided into 8 clusters. This study demonstrated that A. soli accounted for a high proportion of Acinetobacter isolates causing bacteremia at a Japanese tertiary hospital. Non-A. baumannii species were identified more frequently than A. baumannii and carbapenem-nonsusceptible isolates were found among the non-A. baumannii strains. These results emphasize the importance of performing epidemiological investigations of Acinetobacter species.

  1. sal Genes Determining the Catabolism of Salicylate Esters Are Part of a Supraoperonic Cluster of Catabolic Genes in Acinetobacter sp. Strain ADP1

    PubMed Central

    Jones, Rheinallt M.; Pagmantidis, Vassilis; Williams, Peter A.

    2000-01-01

    A 5-kbp region upstream of the are-ben-cat genes was cloned from Acinetobacter sp. strain ADP1, extending the supraoperonic cluster of catabolic genes to 30 kbp. Four open reading frames, salA, salR, salE, and salD, were identified from the nucleotide sequence. Reverse transcription-PCR studies suggested that these open reading frames are organized into two convergent transcription units, salAR and salDE. The salE gene, encoding a protein of 239 residues, was ligated into expression vector pET5a. Its product, SalE, was shown to have esterase activity against short-chain alkyl esters of 4-nitrophenol but was also able to hydrolyze ethyl salicylate to ethanol and salicylic acid. A mutant of ADP1 with a Kmr cassette introduced into salE had lost the ability to utilize only ethyl and methyl salicylates of the esters tested as sole carbon sources, and no esterase activity against ethyl salicylate could be detected in cell extracts. SalE was induced during growth on ethyl salicylate but not during growth on salicylate itself. salD encoded a protein of undetermined function with homologies to the Escherichia coli FadL membrane protein, which is involved in facilitating fatty acid transport, and a number of other proteins detected during aromatic catabolism, which may also function in hydrocarbon transport or uptake processes. A Kmr cassette insertion in salD deleteriously affected cell growth and viability. The salA and salR gene products closely resemble two Pseudomonas proteins, NahG and NahR, respectively encoding salicylate hydroxylase and the LysR family regulator of both salicylate and naphthalene catabolism. salA was cloned into pUC18 together with salR and salE, and its gene product showed salicylate-inducible hydroxylase activity against a range of substituted salicylates, with the same relative specific activities as found in wild-type ADP1 grown on salicylate. Mutations involving insertion of Kmr cassettes into salA and salR eliminated expression of salicylate

  2. Diversity of Group I and II Clostridium botulinum Strains from France Including Recently Identified Subtypes

    PubMed Central

    Mazuet, Christelle; Legeay, Christine; Sautereau, Jean; Ma, Laurence; Bouchier, Christiane; Bouvet, Philippe; Popoff, Michel R.

    2016-01-01

    In France, human botulism is mainly food-borne intoxication, whereas infant botulism is rare. A total of 99 group I and II Clostridium botulinum strains including 59 type A (12 historical isolates [1947–1961], 43 from France [1986–2013], 3 from other countries, and 1 collection strain), 31 type B (3 historical, 23 recent isolates, 4 from other countries, and 1 collection strain), and 9 type E (5 historical, 3 isolates, and 1 collection strain) were investigated by botulinum locus gene sequencing and multilocus sequence typing analysis. Historical C. botulinum A strains mainly belonged to subtype A1 and sequence type (ST) 1, whereas recent strains exhibited a wide genetic diversity: subtype A1 in orfX or ha locus, A1(B), A1(F), A2, A2b2, A5(B2′) A5(B3′), as well as the recently identified A7 and A8 subtypes, and were distributed into 25 STs. Clostridium botulinum A1(B) was the most frequent subtype from food-borne botulism and food. Group I C. botulinum type B in France were mainly subtype B2 (14 out of 20 historical and recent strains) and were divided into 19 STs. Food-borne botulism resulting from ham consumption during the recent period was due to group II C. botulinum B4. Type E botulism is rare in France, 5 historical and 1 recent strains were subtype E3. A subtype E12 was recently identified from an unusual ham contamination. Clostridium botulinum strains from human botulism in France showed a wide genetic diversity and seems to result not from a single evolutionary lineage but from multiple and independent genetic rearrangements. PMID:27189984

  3. Diversity of Group I and II Clostridium botulinum Strains from France Including Recently Identified Subtypes.

    PubMed

    Mazuet, Christelle; Legeay, Christine; Sautereau, Jean; Ma, Laurence; Bouchier, Christiane; Bouvet, Philippe; Popoff, Michel R

    2016-06-13

    In France, human botulism is mainly food-borne intoxication, whereas infant botulism is rare. A total of 99 group I and II Clostridium botulinum strains including 59 type A (12 historical isolates [1947-1961], 43 from France [1986-2013], 3 from other countries, and 1 collection strain), 31 type B (3 historical, 23 recent isolates, 4 from other countries, and 1 collection strain), and 9 type E (5 historical, 3 isolates, and 1 collection strain) were investigated by botulinum locus gene sequencing and multilocus sequence typing analysis. Historical C. botulinum A strains mainly belonged to subtype A1 and sequence type (ST) 1, whereas recent strains exhibited a wide genetic diversity: subtype A1 in orfX or ha locus, A1(B), A1(F), A2, A2b2, A5(B2') A5(B3'), as well as the recently identified A7 and A8 subtypes, and were distributed into 25 STs. Clostridium botulinum A1(B) was the most frequent subtype from food-borne botulism and food. Group I C. botulinum type B in France were mainly subtype B2 (14 out of 20 historical and recent strains) and were divided into 19 STs. Food-borne botulism resulting from ham consumption during the recent period was due to group II C. botulinum B4. Type E botulism is rare in France, 5 historical and 1 recent strains were subtype E3. A subtype E12 was recently identified from an unusual ham contamination. Clostridium botulinum strains from human botulism in France showed a wide genetic diversity and seems to result not from a single evolutionary lineage but from multiple and independent genetic rearrangements.

  4. Acinetobacter seifertii sp. nov., a member of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex isolated from human clinical specimens.

    PubMed

    Nemec, Alexandr; Krizova, Lenka; Maixnerova, Martina; Sedo, Ondrej; Brisse, Sylvain; Higgins, Paul G

    2015-03-01

    This study aimed to define the taxonomic status of a phenetically distinct group of 16 strains that corresponds to Acinetobacter genomic species 'close to 13TU', a provisional genomic species of the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex recognized by Gerner-Smidt and Tjernberg in 1993. These strains have been isolated in different countries since the early 1990s and were mostly recovered from human clinical specimens. They were compared with 45 reference strains representing the known taxa of the ACB complex using taxonomic methods relevant to the genus Acinetobacter. Based on sequence analysis of the concatenated partial sequences (2976 bp) of seven housekeeping genes, the 16 strains formed a tight and well-supported cluster (intracluster sequence identity of ≥98.4 %) that was clearly separated from the other members of the ACB complex (≤94.7 %). The species status of the group was supported by average nucleotide identity values of ≤91.7 % between the whole genome sequence of representative strain NIPH 973(T) (NCBI accession no. APOO00000000) and those of the other species. In addition, whole-cell matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) MS analyses indicated the distinctness of the group at the protein level. Metabolic and physiological tests revealed several typical features of the group, although they did not allow its reliable differentiation from the other members of the ACB complex. We conclude that the 16 strains represent a distinct novel species, for which we propose the name Acinetobacter seifertii sp. nov. The type strain is NIPH 973(T) ( = CIP 110471(T) = CCUG 34785(T) = CCM 8535(T)).

  5. Complete Genome Sequence and Methylome Analysis of Acinetobacter calcoaceticus 65

    PubMed Central

    Fomenkov, Alexey; Vincze, Tamas; Degtyarev, Sergey K.

    2017-01-01

    ABSTRACT Acinetobacter calcoaceticus 65 is the original source strain for the restriction enzyme Acc65I. Its complete sequence and full methylome were determined using single-molecule real-time (SMRT) sequencing. PMID:28336599

  6. Antimicrobial effects of Ferula gummosa Boiss gum against extended-spectrum β-lactamase producing Acinetobacter clinical isolates

    PubMed Central

    Afshar, Fatemeh Farid; Saffarian, Parvaneh; Hosseini, Hamideh Mahmoodzadeh; Sattarian, Fereshteh; Amin, Mohsen; Fooladi, Abbas Ali Imani

    2016-01-01

    Background and Objectives: Acinetobacter spp. are important causes of nosocomial infections. They possess various antibiotic resistance mechanisms including extended spectrum beta lactamases (ESBLs). The aim of this study was to determine antibiotic resistance profile of Acinetobacter clinical isolates especially among ESBL-producing strains and to investigate the antimicrobial effects of oleo-gum-resin extract and essential oil of Ferula gummosa Boiss. Materials and Methods: 120 Acinetobacter strains were isolated from various clinical samples of hospitalized patients in Baqiyatallah hospital, Tehran during 2011–2012. Antibiotic susceptibility test was performed on the isolates using disk diffusion method. To detect and confirm the ESBL-positive isolates, phenotypic and genotypic tests were performed. Three types of F. gummosa oleo-gum-resin extracts and essential oils were prepared and the bioactive components of F. gummosa Boiss extracts were determined by GC-Mass chromatography. F. gummosa antimicrobial activity was evaluated against standard strain of Acinetobacter baumannii (ATCC19606) as well as Acinetobacter clinical isolates using well and disk diffusion methods. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by broth microdilution method. Results: 46 isolates were resistant to all tested antibiotics. All clinical isolates were resistant to cefotaxime. 12.94% of the isolates were phenotypically ESBL-producing among which 94.2% carried ESBL genes ( bla PER-1 , bla OXA-4 and bla CTX-M ) detected by PCR. Oleo-gum-resin of F. gummosa had significant antibacterial activity and alcoholic essential oil had higher inhibitory effect on Acinetobacter strains (MIC of 18.75 mg/ml). Conclusion: Ferula gummosa extract contained components with well-known antimicrobial effects. PMID:28210466

  7. Acinetobacter baumannii and A. pittii clinical isolates lack adherence and cytotoxicity to lung epithelial cells in vitro.

    PubMed

    Lázaro-Díez, María; Navascués-Lejarza, Teresa; Remuzgo-Martínez, Sara; Navas, Jesús; Icardo, José Manuel; Acosta, Felix; Martínez-Martínez, Luis; Ramos-Vivas, José

    2016-09-01

    The molecular and genetic basis of Acinetobacter baumannii and Acinetobacter pittii virulence remains poorly understood, and there is still lack of knowledge in host cell response to these bacteria. In this study, we have used eleven clinical Acinetobacter strains (A. baumannii n = 5; A. pittii n = 6) to unravel bacterial adherence, invasion and cytotoxicity to human lung epithelial cells. Our results showed that adherence to epithelial cells by Acinetobacter strains is scarce and cellular invasion was not truly detected. In addition, all Acinetobacter strains failed to induce any cytotoxic effect on A549 cells.

  8. Reliability of phenotypic tests for identification of Acinetobacter species.

    PubMed Central

    Gerner-Smidt, P; Tjernberg, I; Ursing, J

    1991-01-01

    A numerical approach was used for identification of 198 Acinetobacter strains assigned to DNA groups according to the classification of Tjernberg and Ursing (I. Tjernberg and J. Ursing, APMIS 97:595-605, 1989). The matrix used was constructed from data published by Bouvet and Grimont (P.J.M. Bouvet and P.A.D. Grimont, Int. J. Syst. Bacteriol. 36:228-240, 1986) and Bouvet and Jeanjean (P.J.M. Bouvet and S. Jeanjean, Res. Microbiol. 140:291-299, 1989). The tests chosen were those of the simplified identification scheme for Acinetobacter species devised by Bouvet and Grimont (P.J.M. Bouvet and P.A.D. Grimont, Ann. Inst. Pasteur/Microbiol. 138:569-578, 1987), namely, growth at 37, 41, and 44 degrees C, oxidation of glucose, gelatin hydrolysis, and assimilation of 14 carbon sources. Of the strains tested, 181 represented 12 DNA groups in the matrix; at a probability level of greater than or equal to 0.95, 78% of them were correctly identified, 2.2% were misidentified, and 19.8% were not identified. Seventeen strains represented two DNA groups not included in the matrix; nine of them were incorrectly assigned to a DNA group by these phenotypic tests. Because of problems of separating strains belonging to DNA groups 1, 2, 3, and 13 by using the phenotypic tests proposed by Bouvet and Grimont (Ann. Inst. Pasteur/Microbiol.), we suggest that these groups should be referred to as the Acinetobacter calcoaceticus-A. baumannii complex. PMID:2007635

  9. Description of Leeds Acinetobacter Medium, a new selective and differential medium for isolation of clinically important Acinetobacter spp., and comparison with Herellea agar and Holton's agar.

    PubMed Central

    Jawad, A; Hawkey, P M; Heritage, J; Snelling, A M

    1994-01-01

    Acinetobacter spp. are responsible for an increasing number of opportunistic, nosocomial infections. They have been isolated from diverse inanimate objects in the hospital environment and are resistant to most of the commonly used antibiotics. Existing media for the isolation of Acinetobacter spp. are either nonselective, allowing the growth of unwanted bacteria, or too inhibitory, inhibiting the growth of many Acinetobacter strains. For the rapid isolation and effective control of Acinetobacter infection, a new selective and differential medium, Leeds Acinetobacter Medium (LAM), has been developed to isolate Acinetobacter spp. from clinical and environmental sources. The concentration of antibiotics and other ingredients in this medium have been determined according to the results of MIC and viable counts performed for these ingredients. LAM was compared with other selective and differential media for the isolation of Acinetobacter spp. from a local hospital environment and proved to be better in terms of recovery and selectivity. PMID:7814465

  10. Acinetobacter baumannii in human body louse.

    PubMed

    La Scola, Bernard; Raoult, Didier

    2004-09-01

    While we were isolating Bartonella quintana from body lice, 40 Acinetobacter baumannii strains were also isolated and genotyped. One clone was unique and the other was ampicillin susceptible. A. baumannii DNA was later detected in 21% of 622 lice collected worldwide. These findings show an A. baumannii epidemic in human body lice.

  11. Phenotypic characterization and antibiotic resistance of Acinetobacter spp. isolated from aquatic sources.

    PubMed

    Guardabassi, L; Dalsgaard, A; Olsen, J E

    1999-11-01

    A total of 99 Acinetobacter isolates from sewage, freshwater aquaculture habitats, trout intestinal contents and frozen shrimps was characterized phenotypically and antibiotic susceptibility patterns determined. One group of genomic species, including Ac. johnsonii, Ac. lwoffi and spp. 15TU, was detected in all sample types and represented the majority of the isolates (n = 54). Isolates belonging to the Acb complex (Ac. calcoaceticus, Ac. baumannii and genomic species 3) were detected in sewage (n = 6) and frozen shrimps (n = 1), Ac. haemolyticus in frozen shrimps (n = 6) and trout intestinal contents (n = 2) and genomic species 11 in freshwater aquaculture habitats (n = 6) and trout intestinal contents (n = 1). Acinetobacter junii (n = 5), genomic species 10 (n = 2), 14BJ (n = 8) and 16BJ (n = 4) were only isolated from sewage. Acinetobacter isolates from sewage were generally more biochemically reactive and resistant to antimicrobial agents compared with isolates from other sample types. Different strains, often belonging to different genomic species, were isolated from sites situated upstream and downstream of the discharge point of a pharmaceutical plant. This finding supported the hypothesis that the waste effluent from the pharmaceutical plant was likely to cause a change in the distribution of Acinetobacter spp. by selecting and/or introducing antibiotic-resistant strains into the recipient sewers.

  12. Staring at the Cold Sun: Blue Light Regulation Is Distributed within the Genus Acinetobacter

    PubMed Central

    Golic, Adrián; Vaneechoutte, Mario; Nemec, Alexandr; Viale, Alejandro M.; Actis, Luis A.; Mussi, María Alejandra

    2013-01-01

    We previously showed that the opportunistic nosocomial pathogen Acinetobacter baumannii is able to sense and respond to light via BlsA, a BLUF (Blue-Light-sensing Using FAD)-domain photoreceptor protein. Here, we extend our previous studies showing that light regulation is not restricted to A. baumannii, but rather widespread within the genus Acinetobacter. First, we found that blue light modulates motility and biofilm formation in many species of the genus, including members of the Acinetobacter calcoaceticus-A. baumannii complex. In many of these species blue light acts as a key factor guiding the decision between motility or sessility at 24°C, whereas in A. baumannii, light inhibits both motility and biofilm formation. We also show that light regulation of motility occurred not only at 24°C but also at 37°C in non-A. baumannii species, contrasting the situation of A. baumannii which only shows photoregulation at 24°C. Second, we show that Acinetobacter baylyi (strain ADP1) BLUF-photoreceptors can functionally replace in vivo the A. baumannii 17978 BlsA protein and that the pathways leading to biofilm formation are inversely regulated at 24°C between these two microorganisms. Finally, we found the presence of predicted genes coding BLUF-containing proteins in all Acinetobacter sequenced genomes, even though the copy number is variable among them. Phylogenetic analysis suggests a common origin for all BLUF domains present in members of this genus, and could distinguish well-differentiated clusters that group together BLUF homologs from different species, a situation particularly clear for members of the ACB complex. Despite a role played by these BLUF domain-containing proteins in the photoregulation observed in the members of the genus Acinetobacter is a likely scenario given our findings in A. baumannii and A. baylyi, further research will contribute to confirm this possibility. PMID:23358859

  13. Staring at the cold sun: blue light regulation is distributed within the genus Acinetobacter.

    PubMed

    Golic, Adrián; Vaneechoutte, Mario; Nemec, Alexandr; Viale, Alejandro M; Actis, Luis A; Mussi, María Alejandra

    2013-01-01

    We previously showed that the opportunistic nosocomial pathogen Acinetobacter baumannii is able to sense and respond to light via BlsA, a BLUF (Blue-Light-sensing Using FAD)-domain photoreceptor protein. Here, we extend our previous studies showing that light regulation is not restricted to A. baumannii, but rather widespread within the genus Acinetobacter. First, we found that blue light modulates motility and biofilm formation in many species of the genus, including members of the Acinetobacter calcoaceticus-A. baumannii complex. In many of these species blue light acts as a key factor guiding the decision between motility or sessility at 24°C, whereas in A. baumannii, light inhibits both motility and biofilm formation. We also show that light regulation of motility occurred not only at 24°C but also at 37°C in non-A. baumannii species, contrasting the situation of A. baumannii which only shows photoregulation at 24°C. Second, we show that Acinetobacter baylyi (strain ADP1) BLUF-photoreceptors can functionally replace in vivo the A. baumannii 17978 BlsA protein and that the pathways leading to biofilm formation are inversely regulated at 24°C between these two microorganisms. Finally, we found the presence of predicted genes coding BLUF-containing proteins in all Acinetobacter sequenced genomes, even though the copy number is variable among them. Phylogenetic analysis suggests a common origin for all BLUF domains present in members of this genus, and could distinguish well-differentiated clusters that group together BLUF homologs from different species, a situation particularly clear for members of the ACB complex. Despite a role played by these BLUF domain-containing proteins in the photoregulation observed in the members of the genus Acinetobacter is a likely scenario given our findings in A. baumannii and A. baylyi, further research will contribute to confirm this possibility.

  14. Anthelmintic Avermectins Kill Mycobacterium tuberculosis, Including Multidrug-Resistant Clinical Strains

    PubMed Central

    Lim, Leah E.; Vilchèze, Catherine; Ng, Carol; Jacobs, William R.; Thompson, Charles J.

    2013-01-01

    Avermectins are a family of macrolides known for their anthelmintic activities and traditionally believed to be inactive against all bacteria. Here we report that members of the family, ivermectin, selamectin, and moxidectin, are bactericidal against mycobacterial species, including multidrug-resistant and extensively drug-resistant clinical strains of Mycobacterium tuberculosis. Avermectins are approved for clinical and veterinary uses and have documented pharmacokinetic and safety profiles. We suggest that avermectins could be repurposed for tuberculosis treatment. PMID:23165468

  15. High Frequency of OXA-253-Producing Acinetobacter baumannii in Different Hospitals in Recife, Brazil.

    PubMed

    de Sá Cavalcanti, Felipe Lira; Mendes-Marques, Carina Lucena; Vasconcelos, Crhisllane Rafaele Dos Santos; de Lima Campos, Túlio; Rezende, Antonio Mauro; Xavier, Danilo Elias; Leal, Nilma Cintra; de-Melo-Neto, Osvaldo Pompilio; de Morais, Marcia Maria Camargo; Leal-Balbino, Tereza Cristina

    2017-01-01

    Here, we report the isolation of 31 Acinetobacter baumannii strains producing OXA-253 in a single large Brazilian city. These strains belonged to five different sequence types (STs), including 4 STs not previously associated with blaOXA-253 In all strains, the blaOXA-253 gene was located in a plasmid within a genetic environment similar to what was found previously in Brazil and Italy. The reported data emphasize the successful transmission of the blaOXA-253 gene through a large area and the tendency for this resistance determinant to remain in the A. baumannii population.

  16. High Frequency of OXA-253-Producing Acinetobacter baumannii in Different Hospitals in Recife, Brazil

    PubMed Central

    de Sá Cavalcanti, Felipe Lira; Mendes-Marques, Carina Lucena; Vasconcelos, Crhisllane Rafaele dos Santos; de Lima Campos, Túlio; Rezende, Antonio Mauro; Xavier, Danilo Elias; Leal, Nilma Cintra; de-Melo-Neto, Osvaldo Pompilio; de Morais, Marcia Maria Camargo

    2016-01-01

    ABSTRACT Here, we report the isolation of 31 Acinetobacter baumannii strains producing OXA-253 in a single large Brazilian city. These strains belonged to five different sequence types (STs), including 4 STs not previously associated with blaOXA-253. In all strains, the blaOXA-253 gene was located in a plasmid within a genetic environment similar to what was found previously in Brazil and Italy. The reported data emphasize the successful transmission of the blaOXA-253 gene through a large area and the tendency for this resistance determinant to remain in the A. baumannii population. PMID:27855080

  17. Multidrug-Resistant Acinetobacter baumannii Harboring OXA-24 Carbapenemase, Spain

    PubMed Central

    Acosta, Joshi; Merino, María; Viedma, Esther; Poza, Margarita; Sanz, Francisca; Otero, Joaquín R.; Chaves, Fernando

    2011-01-01

    In February 2006, a patient colonized with a multidrug-resistant sequence type 56 Acinetobacter baumannii strain was admitted to a hospital in Madrid, Spain. This strain spread rapidly and caused a large outbreak in the hospital. Clinicians should be alert for this strain because its spread would have serious health consequences. PMID:21749771

  18. Characterization of Acinetobacter from clinical isolates at Gandhi memorial and associated hospitals, Lucknow.

    PubMed

    Banerjee, Gopa; Singh, Mastan; Goel, Nidhi

    2005-03-01

    The study was conducted in 4140 clinical samples sent to Microbiology department from different department of G.M. and associated hospitals. The samples included 2270 urine, 960 pus, 300 blood, 210 sputum, 180 CSF, 20 intercostal drainage tubes and 150 other swabs like vaginal and urethral, conjunctival smear 30, 10 ascitic fluids and 10 gastric aspirates. Apart from this, 30 specimens were collected from hospitals environment, like linen and trolley. From clinical samples, 43 acinetobacter strains (1.04%) were isolated. 17 strains (0.41%), were from pus, 12 (0.28%), from respiratory tract, 1, was (0.02%) from intercostal drainage secretions, urine 9 (0.22%), blood 1 (0.2%) and CSF 3 (.72%). From environmental samples, 7 strains (23.33%) were isolated. All the isolated strains were identified by routine biochemical tests. They were preserved in 1 % agar media for characterization. Characterization was done on the basis of growth at 37 degrees c, 41 degrees c and 44 degrees c, hemolysis, gelatin hydrolysis, acid from glucose, utilization of citrate, L-phenyl alanine, malonate, B-alanine, L-arginine, L-ornithine and L-aspartate. Among species identified Acinetobacter baumannii was 30 (69.67%), from clinical specimens and 5 (71.42%) from environment, Acinetobacter lwoffi was 10 (23.25%) from clinical specimen and 2 from environmental specimen, Acinetobacter hemolyticus was 3 (6.97%) and none from the environment. All the strains were resistant to penicillin. The sensitivity pattern showed gentamycin 64% sensitive, cotrimaxazole 42% cefotoxin 32% ciprofloxacine 26% and tetracycline 16%.

  19. Transmission line model for strained quantum well lasers including carrier transport and carrier heating effects.

    PubMed

    Xia, Mingjun; Ghafouri-Shiraz, H

    2016-03-01

    This paper reports a new model for strained quantum well lasers, which are based on the quantum well transmission line modeling method where effects of both carrier transport and carrier heating have been included. We have applied this new model and studied the effect of carrier transport on the output waveform of a strained quantum well laser both in time and frequency domains. It has been found that the carrier transport increases the turn-on, turn-off delay times and damping of the quantum well laser transient response. Also, analysis in the frequency domain indicates that the carrier transport causes the output spectrum of the quantum well laser in steady state to exhibit a redshift which has a narrower bandwidth and lower magnitude. The simulation results of turning-on transients obtained by the proposed model are compared with those obtained by the rate equation laser model. The new model has also been used to study the effects of pump current spikes on the laser output waveforms properties, and it was found that the presence of current spikes causes (i) wavelength blueshift, (ii) larger bandwidth, and (iii) reduces the magnitude and decreases the side-lobe suppression ratio of the laser output spectrum. Analysis in both frequency and time domains confirms that the new proposed model can accurately predict the temporal and spectral behaviors of strained quantum well lasers.

  20. Organic acid production and plant growth promotion as a function of phosphate solubilization by Acinetobacter rhizosphaerae strain BIHB 723 isolated from the cold deserts of the trans-Himalayas.

    PubMed

    Gulati, Arvind; Sharma, Natasha; Vyas, Pratibha; Sood, Swati; Rahi, Praveen; Pathania, Vijaylata; Prasad, Ramdeen

    2010-11-01

    An efficient phosphate-solubilizing plant growth-promoting Acinetobacter rhizosphaerae strain BIHB 723 exhibited significantly higher solubilization of tricalcium phosphate (TCP) than Udaipur rock phosphate (URP), Mussoorie rock phosphate (MRP) and North Carolina rock phosphate (NCRP). Qualitative and quantitative differences were discerned in the gluconic, oxalic, 2-keto gluconic, lactic, malic and formic acids during the solubilization of various inorganic phosphates by the strain. Gluconic acid was the main organic acid produced during phosphate solubilization. Formic acid production was restricted to TCP solubilization and oxalic acid production to the solubilization of MRP, URP and NCRP. A significant increase in plant height, shoot fresh weight, shoot dry weight, root length, root dry weight, and root, shoot and soil phosphorus (P) contents was recorded with the inoculated treatments over the uninoculated NP(0)K or NP(TCP)K treatments. Plant growth promotion as a function of phosphate solubilization suggested that the use of bacterial strain would be a beneficial addition to the agriculture practices in TCP-rich soils in reducing the application of phosphatic fertilizers.

  1. The Population Structure of Acinetobacter baumannii: Expanding Multiresistant Clones from an Ancestral Susceptible Genetic Pool

    PubMed Central

    Diancourt, Laure; Passet, Virginie; Nemec, Alexandr; Dijkshoorn, Lenie; Brisse, Sylvain

    2010-01-01

    Outbreaks of hospital infections caused by multidrug resistant Acinetobacter baumannii strains are of increasing concern worldwide. Although it has been reported that particular outbreak strains are geographically widespread, little is known about the diversity and phylogenetic relatedness of A. baumannii clonal groups. Sequencing of internal portions of seven housekeeping genes (total 2,976 nt) was performed in 154 A. baumannii strains covering the breadth of known diversity and including representatives of previously recognized international clones, and in 19 representatives of other Acinetobacter species. Restricted amounts of diversity and a star-like phylogeny reveal that A. baumannii is a genetically compact species that suffered a severe bottleneck in the recent past, possibly linked to a restricted ecological niche. A. baumannii is neatly demarcated from its closest relative (genomic species 13TU) and other Acinetobacter species. Multilocus sequence typing analysis demonstrated that the previously recognized international clones I to III correspond to three clonal complexes, each made of a central, predominant genotype and few single locus variants, a hallmark of recent clonal expansion. Whereas antimicrobial resistance was almost universal among isolates of these and a novel international clone (ST15), isolates of the other genotypes were mostly susceptible. This dichotomy indicates that antimicrobial resistance is a major selective advantage that drives the ongoing rapid clonal expansion of these highly problematic agents of nosocomial infections. PMID:20383326

  2. Differentiation of strains in Mycobacterium tuberculosis complex by DNA sequence polymorphisms, including rapid identification of M. bovis BCG.

    PubMed Central

    Frothingham, R

    1995-01-01

    The Mycobacterium tuberculosis complex includes M. tuberculosis, M. bovis, M. microti, and M. africanum. Seven strains of the M. tuberculosis complex were sequenced in a region of about 300 bp which contains multiple 15-bp tandem repeats and which is part of a 1,551-bp open reading frame. Four distinct sequences were obtained, each defining a sequevar. A sequevar includes the strain or strains with a given sequence. The type strain M. tuberculosis TMC 102 (H37Rv) was designated sequevar MED-G. When compared to MED-G, sequevar LONG had an insertion of one 15-bp tandem repeat and sequevar SHORT had a deletion of one tandem repeat. Sequevar MED-C had a G-->C substitution, coding for the conservative change Ser-->Thr. BanI cuts only sequevar MED-C at the site of the substitution. PCR-restriction enzyme analysis was used to determine the sequevars of 92 M. tuberculosis complex strains. All 23 M. bovis BCG strains belonged to sequevar MED-C. The M. africanum type strain was sequevar SHORT. The remaining 68 strains of M. tuberculosis, M. bovis (not BCG), and M. microti were sequevars LONG (3 strains) or MED-G (65 strains). PCR-restriction enzyme analysis was applied to reference strains and clinical isolates with a worldwide distribution. This method provides rapid, sensitive, and specific identification of the important vaccine strain M. bovis BCG. PMID:7790448

  3. Gas chromatography of bacterial whole cell methanolysates. VII. Fatty acid composition of Acinetobacter in relation to the taxonomy of Neisseriaceae.

    PubMed

    Jantzen, E; Bryn, K; Bergan, T; Bovre, K

    1975-12-01

    The cellular fatty acids of seventeen Acinetobacter strains were determined. Most acids identified were previously found in neisseriae and moraxellae. Specific for Acinetobacter was 2-hydroxydodecanoid acid and a few minor unidentified components. The fatty acid data were analysed by numerical methods and compared with previous results obtained for neisseriae and moraxellae. The findings were consistent with genetic evidence for some affinities of genus Acinetobacter to genus Moraxella and "false neisseriae". Occasionally, a high resemblance in fatty acid pattern was demonstrated between a Moraxella strain and certain strains of Acinetobacter, and also between an Acinetobacter strain and certain "true neisseriae". Still, the acinetobacters constituted one single cluster separated from the other genera of Neisseriaceae.

  4. Acinetobacter junii as an aetiological agent of corneal ulcer.

    PubMed

    Broniek, G; Langwińska-Wośko, E; Szaflik, J; Wróblewska, M

    2014-12-01

    Rods of the Acinetobacter genus are present mainly in the external environment (e.g. water, soil) and in animals, while in humans they may comprise physiological flora. The main pathogenic species is Acinetobacter baumannii complex, which constitutes a common cause of nosocomial infections, particularly in patients with underlying diseases and risk factors (e.g. prior broad-spectrum antibiotic therapy, malignancy, central venous catheter, mechanical ventilation); however, infections of the eye caused by strains of Acinetobacter spp. are very rare. We report a unique case of community-acquired corneal ulcer caused by Acinetobacter non-baumannii (possibly A. junii), in a patient with no risk factors identified. The case highlights the need for obtaining a sample from the cornea for bacteriological culture in the case of suspected ophthalmic infection as identification of the pathogen, and assessment of its susceptibility profile enables proper antibiotic therapy, improves the outcome and may constitute an eyesight-saving management.

  5. Evaluation of the in vitro colistin susceptibility of Pseudomonas aeruginosa and Acinetobacter baumannii strains at a tertiary care centre in Western Turkey.

    PubMed

    Ece, Gulfem; Samlioglu, Pinar; Atalay, Sabri; Kose, Sukran

    2014-03-01

    Multidrug-resistant gram-negative bacteria are an important issue in intensive care units worldwide. Colistin, one of the earliest polymyxin antibiotics, was once widely used for the treatment of gram-negative bacterial infections. However, its use is now limited due to concerns over nephrotoxicity. The appearance of multidrug-resistant species, including A. baumannii and P. aeruginosa, has led to the re-emergence of this class of drugs. The aim of this study was to evaluate the susceptibility of A. baumannii and P. aeruginosa isolates to colistin and other antibiotics. The antimicrobial susceptibility of A. baumannii and P. aeruginosa isolates to colistin and other antibiotics was evaluated between January 2011 and October 2012 at Tepecik Education and Research Hospital in Izmir, Turkey. Clinical isolates were identified using an automatized Vitek 2.0 system. Colistin susceptibility was measured by E-test; the susceptibility profiles of other antibiotics were evaluated using the Kirby Bauer disk-diffusion method. A total of 149 isolates were included in the study, consisting of 98 A. baumannii and 51 P. aeruginosa isolates. The MICs of colistin against A. baumannii were 0.125-2.0 mcg/mL, and 0.25-2.0 mcg/mL against P. aeruginosa; all multidrug-resistant strains examined in this study were susceptible to colistin. Recently, colistin has re-emerged as an effective treatment for infections due to multidrug-resistant A. baumannii, P. aeruginosa, and Klebsiella pneumoniae. All isolates examined in this study were susceptible to colistin, suggesting it could be a viable alternative for the treatment of infections with multidrug-resistant strains.

  6. Genomic and functional analysis of the type VI secretion system in Acinetobacter.

    PubMed

    Weber, Brent S; Miyata, Sarah T; Iwashkiw, Jeremy A; Mortensen, Brittany L; Skaar, Eric P; Pukatzki, Stefan; Feldman, Mario F

    2013-01-01

    The genus Acinetobacter is comprised of a diverse group of species, several of which have raised interest due to potential applications in bioremediation and agricultural purposes. In this work, we show that many species within the genus Acinetobacter possess the genetic requirements to assemble a functional type VI secretion system (T6SS). This secretion system is widespread among Gram negative bacteria, and can be used for toxicity against other bacteria and eukaryotic cells. The most studied species within this genus is A. baumannii, an emerging nosocomial pathogen that has become a significant threat to healthcare systems worldwide. The ability of A. baumannii to develop multidrug resistance has severely reduced treatment options, and strains resistant to most clinically useful antibiotics are frequently being isolated. Despite the widespread dissemination of A. baumannii, little is known about the virulence factors this bacterium utilizes to cause infection. We determined that the T6SS is conserved and syntenic among A. baumannii strains, although expression and secretion of the hallmark protein Hcp varies between strains, and is dependent on TssM, a known structural protein required for T6SS function. Unlike other bacteria, A. baumannii ATCC 17978 does not appear to use its T6SS to kill Escherichia coli or other Acinetobacter species. Deletion of tssM does not affect virulence in several infection models, including mice, and did not alter biofilm formation. These results suggest that the T6SS fulfils an important but as-yet-unidentified role in the various lifestyles of the Acinetobacter spp.

  7. Plasmid carriage of bla NDM-1 in clinical Acinetobacter baumannii isolates from India.

    PubMed

    Jones, Lim S; Toleman, Mark A; Weeks, Janis L; Howe, Robin A; Walsh, Timothy R; Kumarasamy, Karthikeyan K

    2014-07-01

    NDM-1 probably emerged in Acinetobacter species prior to its dissemination among Enterobacteriaceae, and NDM-1-like enzymes are increasingly reported in Acinetobacter species. Here, we report on the genetic context of blaNDM-1 in the earliest known NDM-1-producing organisms, clinical isolates of Acinetobacter from India in 2005. These strains harbor blaNDM-1 plasmids of different sizes. The gene is associated with the remnants of the Tn125 transposon normally associated with blaNDM-1 in Acinetobacter spp. The transposon has been disrupted by the IS26 insertion and subsequent movement events.

  8. Emergence of rifampicin, tigecycline, and colistin-resistant Acinetobacter baumannii in Iran; spreading of MDR strains of novel International Clone variants.

    PubMed

    Bahador, Abbas; Taheri, Mohammad; Pourakbari, Babak; Hashemizadeh, Zahra; Rostami, Hossein; Mansoori, Noormohamad; Raoofian, Reza

    2013-10-01

    Multidrug-resistant Acinetobacter baumannii infections are serious challenges for clinicians because of A. baumannii propensity to acquire resistance to a wide spectrum of antimicrobial agents. In this study, 91 A. baumannii isolates from patients in tertiary intensive care units of three university hospitals in the north, central, and south of Iran were selected and tested for susceptibility to 22 antimicrobials; amplified restriction fragment polymorphism and multiplex polymerase chain reaction methods were used to determine genetic relationships and International Clone (IC) of A. baumannii isolates, respectively. Twenty-four genotypes were identified in A. baumannii isolates. About 91.2% of isolates categorized into 4 distinct clusters; one was more heterogeneous and observed across the three locations. A considerable number of the isolates (27.5%) belonged to the novel IC variant, sequence group 7 (SG7), which was geographically widespread in three locations. The drug resistance pattern showed that 14.2%, 20%, and 77% of the A. baumannii isolates were resistant to colistin, tigecycline, and rifampicin, respectively. Nine percent of isolates (8) showed simultaneous resistance to colistin, rifampicin, and tigecycline. Interestingly, all of them were susceptible to ampicillin-sulbactam and/or tobramycin. According to our results, SG7 could be considered as a pan-Iranian clone.

  9. Biological features of biofilm-forming ability of Acinetobacter baumannii strains derived from 121 elderly patients with hospital-acquired pneumonia.

    PubMed

    Zhang, Duchao; Xia, Jingjing; Xu, Yaping; Gong, Meiliang; Zhou, Yu; Xie, Lixin; Fang, Xiangqun

    2016-02-01

    This study is to investigate a biological activity of Acinetobacter baumannii isolates from sputum specimens of 121 elderly patients with hospital-acquired pneumonia. The ability of the isolates to form biofilms was quantitatively assessed by crystal violet staining, and adhesive property was examined using Giemsa staining. Biofilm-forming ability by the isolates was employed to test antimicrobial resistance and examine sources and clinical manifestations. The isolates grew as biofilm on abiotic surface at the indicated temperatures after a 48 h of incubation. 27.3 % of the isolates were strongly biofilm-positive in the samples, and 84.8 % displayed high adhesion ability (P < 0.05). All of the isolates showed antibiotic resistance at different levels, and the isolates produced strong biofilm exhibited low-level resistance to gentamicin, minocycline and ceftazidime (P < 0.05). The patients' experience in ICU, use of antibiotics and estimation of APACHE II (<17) were related to incidence of strong biofilm formation with no clinical manifestations found in the study. All clinical isolates are able to form biofilms which refer to adhesive efficiency and antibiotic resistance. Patient experiences in ICU surveillance, use of antibiotics and APACHE II scores are involved in biofilm-forming ability by the nosocomial pathogen derived from the hospitalized patients.

  10. Clinical and antimicrobial profile of Acinetobacter spp.: An emerging nosocomial superbug.

    PubMed

    Tripathi, Purti C; Gajbhiye, Sunita R; Agrawal, Gopal Nandlal

    2014-01-01

    Recently, Acinetobacter has emerged as significant hospital pathogen, notoriously known to acquire antibiotic resistance to most of the commonly prescribed antimicrobials. Many risk factors are associated with Acinetobacter infections, especially in patients in intensive care unit (ICU). This study aims to isolate Acinetobacter from various clinical specimens and to determine its antimicrobial sensitivity pattern. Identification, speciation and antimicrobial sensitivity testing were performed using the standard microbiological techniques. Slime production was also tested by microtiter plate and tube method. From the processed clinical specimens, 107 Acinetobacter strains (1.02%) were isolated of which 76 (0.74%) isolates were from general wards and 31 (11.96%) were from ICU. Significantly higher percentage of Acinetobacter strains was found in ICU compared with general wards (P < 0.05). Most common Acinetobacter infection was abscess. Infections were more common in males and were associated with major risk factors such as post-surgical, diabetes mellitus, catheterization, extended hospital stay and prolonged antibiotic usage. Acinetobacter baumanii was the most common species isolated to cause abscess, wound infection, etc. 62.61% and 28.97% isolates produced slime by microtiter plate and tube method. Imipenem was most sensitive drug followed by amikacin. Ceftazidime, cefotaxime, piperacillin were most resistant. 43.00% isolates were IPM resistant. A. baumanii was more resistant to commonly used antimicrobials. Acinetobacter nosocomial infections resistant to most antimicrobials have emerged, especially in ICU. Early identification and continued surveillance of prevalent organism will help prevent the spread of Acinetobacter in hospital environment.

  11. Nosocomial Infections Caused by Acinetobacter baumannii: Are We Losing the Battle?

    PubMed

    Protic, Dragana; Pejovic, Aleksa; Andjelkovic, Dragana; Djukanovic, Nina; Savic, Dragana; Piperac, Pavle; Markovic Denic, Ljiljana; Zdravkovic, Marija; Todorovic, Zoran

    2016-04-01

    The incidence of nosocomial infections caused by multi-drug- and extended-drug resistant strains of Acinetobacter is constantly increasing all over the world, with a high mortality rate. We analyzed the in-hospital data on the sensitivity of Acinetobacter baumannii isolates and correlated them with antibiotic treatment and clinical outcomes of nosocomial infections over a 17-mo period. Retrospective analysis was performed at the Clinical Center "Bezanijska kosa," Belgrade, Serbia. Microbiologic data (number and sensitivity of A. baumannii isolates) and clinical data (medical records of 41 randomly selected patients who developed nosocomial infection caused by A. baumannii) were matched. Acinetobacter baumannii, detected in 279 isolates and obtained from 19 patients (12% of all samples), was resistant to almost all antibiotics tested, including carbapenems, with the exception of colistin and tigecycline. It was obtained most often from the respiratory tract samples. Empiric treatment of the nosocomial infections (pneumonia in 75% of cases) involved cephalosporins, metronidazole, and carbapenems (80%, 66%, and 61% of patients, respectively), whereas tigecyclin and colistin were used primarily in targeted therapy (20% and 12% of patients, respectively). The mortality rate of patients treated empirically was significantly higher (p < 0.01), reaching 100% in the elderly. Nosocomial A. baumannii infections represent a significant clinical problem because of their high incidence, lack of susceptibility to the most commonly used antibiotics, and the often inappropriate treatment, which favors the development of multi-drug-resistant strains.

  12. Medically Relevant Acinetobacter Species Require a Type II Secretion System and Specific Membrane-Associated Chaperones for the Export of Multiple Substrates and Full Virulence.

    PubMed

    Harding, Christian M; Kinsella, Rachel L; Palmer, Lauren D; Skaar, Eric P; Feldman, Mario F

    2016-01-01

    Acinetobacter baumannii, A. nosocomialis, and A. pittii have recently emerged as opportunistic human pathogens capable of causing severe human disease; however, the molecular mechanisms employed by Acinetobacter to cause disease remain poorly understood. Many pathogenic members of the genus Acinetobacter contain genes predicted to encode proteins required for the biogenesis of a type II secretion system (T2SS), which have been shown to mediate virulence in many Gram-negative organisms. Here we demonstrate that Acinetobacter nosocomialis strain M2 produces a functional T2SS, which is required for full virulence in both the Galleria mellonella and murine pulmonary infection models. Importantly, this is the first bona fide secretion system shown to be required for virulence in Acinetobacter. Using bioinformatics, proteomics, and mutational analyses, we show that Acinetobacter employs its T2SS to export multiple substrates, including the lipases LipA and LipH as well as the protease CpaA. Furthermore, the Acinetobacter T2SS, which is found scattered amongst five distinct loci, does not contain a dedicated pseudopilin peptidase, but instead relies on the type IV prepilin peptidase, reinforcing the common ancestry of these two systems. Lastly, two of the three secreted proteins characterized in this study require specific chaperones for secretion. These chaperones contain an N-terminal transmembrane domain, are encoded adjacently to their cognate effector, and their disruption abolishes type II secretion of their cognate effector. Bioinformatic analysis identified putative chaperones located adjacent to multiple previously known type II effectors from several Gram-negative bacteria, which suggests that T2SS chaperones constitute a separate class of membrane-associated chaperones mediating type II secretion.

  13. Medically Relevant Acinetobacter Species Require a Type II Secretion System and Specific Membrane-Associated Chaperones for the Export of Multiple Substrates and Full Virulence

    PubMed Central

    Harding, Christian M.; Kinsella, Rachel L.; Palmer, Lauren D.; Skaar, Eric P.; Feldman, Mario F.

    2016-01-01

    Acinetobacter baumannii, A. nosocomialis, and A. pittii have recently emerged as opportunistic human pathogens capable of causing severe human disease; however, the molecular mechanisms employed by Acinetobacter to cause disease remain poorly understood. Many pathogenic members of the genus Acinetobacter contain genes predicted to encode proteins required for the biogenesis of a type II secretion system (T2SS), which have been shown to mediate virulence in many Gram-negative organisms. Here we demonstrate that Acinetobacter nosocomialis strain M2 produces a functional T2SS, which is required for full virulence in both the Galleria mellonella and murine pulmonary infection models. Importantly, this is the first bona fide secretion system shown to be required for virulence in Acinetobacter. Using bioinformatics, proteomics, and mutational analyses, we show that Acinetobacter employs its T2SS to export multiple substrates, including the lipases LipA and LipH as well as the protease CpaA. Furthermore, the Acinetobacter T2SS, which is found scattered amongst five distinct loci, does not contain a dedicated pseudopilin peptidase, but instead relies on the type IV prepilin peptidase, reinforcing the common ancestry of these two systems. Lastly, two of the three secreted proteins characterized in this study require specific chaperones for secretion. These chaperones contain an N-terminal transmembrane domain, are encoded adjacently to their cognate effector, and their disruption abolishes type II secretion of their cognate effector. Bioinformatic analysis identified putative chaperones located adjacent to multiple previously known type II effectors from several Gram-negative bacteria, which suggests that T2SS chaperones constitute a separate class of membrane-associated chaperones mediating type II secretion. PMID:26764912

  14. Structural Relationship of the Lipid A Acyl Groups to Activation of Murine Toll-Like Receptor 4 by Lipopolysaccharides from Pathogenic Strains of Burkholderia mallei, Acinetobacter baumannii, and Pseudomonas aeruginosa

    PubMed Central

    Korneev, Kirill V.; Arbatsky, Nikolay P.; Molinaro, Antonio; Palmigiano, Angelo; Shaikhutdinova, Rima Z.; Shneider, Mikhail M.; Pier, Gerald B.; Kondakova, Anna N.; Sviriaeva, Ekaterina N.; Sturiale, Luisa; Garozzo, Domenico; Kruglov, Andrey A.; Nedospasov, Sergei A.; Drutskaya, Marina S.; Knirel, Yuriy A.; Kuprash, Dmitry V.

    2015-01-01

    Toll-like receptor 4 (TLR4) is required for activation of innate immunity upon recognition of lipopolysaccharide (LPS) of Gram-negative bacteria. The ability of TLR4 to respond to a particular LPS species is important since insufficient activation may not prevent bacterial growth while excessive immune reaction may lead to immunopathology associated with sepsis. Here, we investigated the biological activity of LPS from Burkholderia mallei that causes glanders, and from the two well-known opportunistic pathogens Acinetobacter baumannii and Pseudomonas aeruginosa (causative agents of nosocomial infections). For each bacterial strain, R-form LPS preparations were purified by hydrophobic chromatography and the chemical structure of lipid A, an LPS structural component, was elucidated by HR-MALDI-TOF mass spectrometry. The biological activity of LPS samples was evaluated by their ability to induce production of proinflammatory cytokines, such as IL-6 and TNF, by bone marrow-derived macrophages. Our results demonstrate direct correlation between the biological activity of LPS from these pathogenic bacteria and the extent of their lipid A acylation. PMID:26635809

  15. Synergy of Penicillin-Netilmicin Combinations Against Enterococci Including Strains Highly Resistant to Streptomycin or Kanamycin

    PubMed Central

    Sanders, Christine C.

    1977-01-01

    The in vitro activity of combinations of penicillin and netilimicin was determined against 20 clinical isolates of enterococci and compared with that obtained in simultaneous tests with penicillin/sisomicin, penicillin/streptomycin, and penicillin/kanamycin. Synergy between the two drugs in each combination was determined by the use of quantitative kill curves and was defined as a killing by the combination at least 100-fold greater than that produced by the most effective drug alone. Penicillin/netilmicin and penicillin/sisomicin combinations were found to be synergistic against the majority of isolates tested, including strains resistant to penicillin/streptomycin or penicillin/kanamycin combinations. This synergy with penicillin could be demonstrated at a concentration of ≤7 μg/ml for either netilmicin or sisomicin. Studies on the kinetics of killing produced by these combinations showed the rate and extent of killing to be directly dependent upon the organism's relative susceptibility to the aminoglycoside alone and the aminoglycoside concentration in the combination. Results also indicated that the interaction between penicillin and netilmicin was true synergy; i.e., rapid and complete killing was produced by combinations containing each drug at concentrations insufficient to produce any killing alone, and the killing observed could not be produced by either drug alone at a concentration equivalent to the total drug concentration in the combination. The potential clinical application of this synergistic interaction should be investigated further, especially in view of recent reports showing netilmicin to be considerably less toxic than gentamicin in experimental animals. PMID:242509

  16. Enrichment for Hydrogen-Oxidizing Acinetobacter spp. in the Rhizosphere of Hydrogen-Evolving Soybean Root Nodules †

    PubMed Central

    Wong, Tit-Yee; Graham, Lennox; O'Hara, Eileen; Maier, Robert J.

    1986-01-01

    Field soybean plants were inoculated with Hup+ wild-type or H2 uptake-negative (Hup−) mutants of Bradyrhizobium japonicum. For two consecutive summers we found an enrichment for acinetobacters associated with the surfaces of the H2-evolving nodules. Soybean root nodules that evolved H2 had up to 12 times more Acinetobacter spp. bacteria associated with their surfaces than did nodules incapable of evolving H2. All of the newly isolated strains identified as Acinetobacter obtained from the surfaces of root nodules, as well as known established Acinetobacter strains, were capable of oxidizing H2, a property not previously described for this alkane-degrading soil bacterium. Images PMID:16347197

  17. Modeling of stress/strain behavior of fiber-reinforced ceramic matrix composites including stress redistribution

    NASA Technical Reports Server (NTRS)

    Mital, Subodh K.; Murthy, Pappu L. N.; Chamis, Christos C.

    1994-01-01

    A computational simulation procedure is presented for nonlinear analyses which incorporates microstress redistribution due to progressive fracture in ceramic matrix composites. This procedure facilitates an accurate simulation of the stress-strain behavior of ceramic matrix composites up to failure. The nonlinearity in the material behavior is accounted for at the constituent (fiber/matrix/interphase) level. This computational procedure is a part of recent upgrades to CEMCAN (Ceramic Matrix Composite Analyzer) computer code. The fiber substructuring technique in CEMCAN is used to monitor the damage initiation and progression as the load increases. The room-temperature tensile stress-strain curves for SiC fiber reinforced reaction-bonded silicon nitride (RBSN) matrix unidirectional and angle-ply laminates are simulated and compared with experimentally observed stress-strain behavior. Comparison between the predicted stress/strain behavior and experimental stress/strain curves is good. Collectively the results demonstrate that CEMCAN computer code provides the user with an effective computational tool to simulate the behavior of ceramic matrix composites.

  18. Antimicrobial active herbal compounds against Acinetobacter baumannii and other pathogens

    PubMed Central

    Tiwari, Vishvanath; Roy, Ranita; Tiwari, Monalisa

    2015-01-01

    Bacterial pathogens cause a number of lethal diseases. Opportunistic bacterial pathogens grouped into ESKAPE pathogens that are linked to the high degree of morbidity, mortality and increased costs as described by Infectious Disease Society of America. Acinetobacter baumannii is one of the ESKAPE pathogens which cause respiratory infection, pneumonia and urinary tract infections. The prevalence of this pathogen increases gradually in the clinical setup where it can grow on artificial surfaces, utilize ethanol as a carbon source and resists desiccation. Carbapenems, a β-lactam, are the most commonly prescribed drugs against A. baumannii. The high level of acquired and intrinsic carbapenem resistance mechanisms acquired by these bacteria makes their eradication difficult. The pharmaceutical industry has no solution to this problem. Hence, it is an urgent requirement to find a suitable alternative to carbapenem, a commonly prescribed drug for Acinetobacter infection. In order to do this, here we have made an effort to review the active compounds of plants that have potent antibacterial activity against many bacteria including carbapenem resistant strain of A. baumannii. We have also briefly highlighted the separation and identification methods used for these active compounds. This review will help researchers involved in the screening of herbal active compounds that might act as a replacement for carbapenem. PMID:26150810

  19. Antimicrobial active herbal compounds against Acinetobacter baumannii and other pathogens.

    PubMed

    Tiwari, Vishvanath; Roy, Ranita; Tiwari, Monalisa

    2015-01-01

    Bacterial pathogens cause a number of lethal diseases. Opportunistic bacterial pathogens grouped into ESKAPE pathogens that are linked to the high degree of morbidity, mortality and increased costs as described by Infectious Disease Society of America. Acinetobacter baumannii is one of the ESKAPE pathogens which cause respiratory infection, pneumonia and urinary tract infections. The prevalence of this pathogen increases gradually in the clinical setup where it can grow on artificial surfaces, utilize ethanol as a carbon source and resists desiccation. Carbapenems, a β-lactam, are the most commonly prescribed drugs against A. baumannii. The high level of acquired and intrinsic carbapenem resistance mechanisms acquired by these bacteria makes their eradication difficult. The pharmaceutical industry has no solution to this problem. Hence, it is an urgent requirement to find a suitable alternative to carbapenem, a commonly prescribed drug for Acinetobacter infection. In order to do this, here we have made an effort to review the active compounds of plants that have potent antibacterial activity against many bacteria including carbapenem resistant strain of A. baumannii. We have also briefly highlighted the separation and identification methods used for these active compounds. This review will help researchers involved in the screening of herbal active compounds that might act as a replacement for carbapenem.

  20. Acinetobacter indicus sp. nov., isolated from a hexachlorocyclohexane dump site.

    PubMed

    Malhotra, Jaya; Anand, Shailly; Jindal, Swati; Rajagopal, Raman; Lal, Rup

    2012-12-01

    The taxonomic position of a Gram-negative, non-motile, oxidase negative and catalase positive strain, A648(T), isolated from a hexachlorocyclohexane (HCH) dump site located in Lucknow, India, was ascertained by using a polyphasic approach. A comparative analysis of a partial sequence of the rpoB gene and the 16S rRNA gene sequence revealed that strain A648(T) belonged to the genus Acinetobacter. DNA-DNA relatedness values between strain A648(T) and other closely related members (16S rRNA gene sequence similarity greater than 97%), namely Acinetobacter radioresistens DSM 6976(T), A. venetianus ATCC 31012(T), A. baumannii LMG 1041(T), A. parvus LMG 21765(T) A. junii LMG 998(T) and A. soli JCM 15062(T), were found to be less than 8%. The major cellular fatty acids of strain A648(T) were 18:1ω9c (19.6%), summed feature 3 (15.9%), 16:0 (10.6%) and 12:0 (6.4%). The DNA G+C content was 40.4 mol%. The polar lipid profile of strain A648(T) indicated the presence of diphosphatidylglycerol, phosphatidylethanolamine, followed by phosphatidylglycerol and phosphatidylcholine. The predominant polyamine of strain A648(T) was 1,3-diaminopropane and moderate amounts of putrescine, spermidine and spermine were also detected. The respiratory quinone consisted of ubiquinone with nine isoprene units (Q-9). On the basis of DNA-DNA hybridization, phenotypic characteristics and chemotaxonomic and phylogenetic comparisons with other members of the genus Acinetobacter, strain A648(T) is found to be a novel species of the genus Acinetobacter, for which the name Acinetobacter indicus sp. nov. is proposed. The type strain is A648(T) ( = DSM 25388(T) = CCM 7832(T)).

  1. Colistin Dosage without Loading Dose Is Efficacious when Treating Carbapenem-Resistant Acinetobacter baumannii Ventilator-Associated Pneumonia Caused by Strains with High Susceptibility to Colistin.

    PubMed

    Álvarez-Marín, Rocío; López-Rojas, Rafael; Márquez, Juan Antonio; Gómez, María José; Molina, José; Cisneros, José Miguel; Ortiz-Leyba, Carlos; Aznar, Javier; Garnacho-Montero, José; Pachón, Jerónimo

    2016-01-01

    This study aims to analyze the mortality and the length of ICU stay (LOS) of A. baumannii VAP compared to respiratory colonization in patients with mechanical ventilation (MV). A prospective cohort study was performed in an ICU of adult patients (February 2010-June 2011). One hundred patients on MV with A. baumannii in lower respiratory airways were recruited, and classified as VAP or airways colonization according to CPIS criteria, with a punctuation ≥6. LOS, 30-days mortality, A. baumannii bacteremia, and clinical features including antibiotic therapy were recorded. Multivariate analysis (linear and Cox regression) and survival analysis (Kaplan-Meier curves) were performed. Fifty-seven VAP and 43 colonized A. baumannii patients were analyzed. Among the A. baumannii strains, 99% were non-susceptible to carbapenems and the MIC90 of colistin was 0.12 mg/l. Therapy was appropriate in 94.6% of VAP patients, most of them with colistin 6 MIU/day, although in 13 (23.6%) cases colistin was started 48 hours after the onset of VAP. Mortality was similar in both groups (VAP 24.6% vs. colonized 27.9%, p = 0.7). Bacteremia and acute kidney insufficiency were associated with decreased survival (p = 0.02 and p = 0.04, respectively) in VAP patients. LOS was 21.5 (11.5-42.75) vs. 9 (6-22) days for VAP and colonized patients (p = 0.004). VAP (p = 0.003) and age (p = 0.01) were independently related to a longer LOS. Multidrug-resistant A. baumannii VAP treated with colistin does not have a different mortality compared to lower airways colonization, among patients on mechanical-ventilation, in a setting of high susceptibility to colistin of A. baumannii.

  2. Colistin Dosage without Loading Dose Is Efficacious when Treating Carbapenem-Resistant Acinetobacter baumannii Ventilator-Associated Pneumonia Caused by Strains with High Susceptibility to Colistin

    PubMed Central

    López-Rojas, Rafael; Márquez, Juan Antonio; Gómez, María José; Molina, José; Cisneros, José Miguel; Ortiz-Leyba, Carlos; Aznar, Javier; Garnacho-Montero, José; Pachón, Jerónimo

    2016-01-01

    Objectives This study aims to analyze the mortality and the length of ICU stay (LOS) of A. baumannii VAP compared to respiratory colonization in patients with mechanical ventilation (MV). Methods A prospective cohort study was performed in an ICU of adult patients (February 2010–June 2011). One hundred patients on MV with A. baumannii in lower respiratory airways were recruited, and classified as VAP or airways colonization according to CPIS criteria, with a punctuation ≥6. LOS, 30-days mortality, A. baumannii bacteremia, and clinical features including antibiotic therapy were recorded. Multivariate analysis (linear and Cox regression) and survival analysis (Kaplan-Meier curves) were performed. Results Fifty-seven VAP and 43 colonized A. baumannii patients were analyzed. Among the A. baumannii strains, 99% were non-susceptible to carbapenems and the MIC90 of colistin was 0.12 mg/l. Therapy was appropriate in 94.6% of VAP patients, most of them with colistin 6 MIU/day, although in 13 (23.6%) cases colistin was started 48 hours after the onset of VAP. Mortality was similar in both groups (VAP 24.6% vs. colonized 27.9%, p = 0.7). Bacteremia and acute kidney insufficiency were associated with decreased survival (p = 0.02 and p = 0.04, respectively) in VAP patients. LOS was 21.5 (11.5–42.75) vs. 9 (6–22) days for VAP and colonized patients (p = 0.004). VAP (p = 0.003) and age (p = 0.01) were independently related to a longer LOS. Conclusions Multidrug-resistant A. baumannii VAP treated with colistin does not have a different mortality compared to lower airways colonization, among patients on mechanical-ventilation, in a setting of high susceptibility to colistin of A. baumannii. PMID:27992528

  3. Efflux Pump Inhibitor Phenylalanine-Arginine Β-Naphthylamide Effect on the Minimum Inhibitory Concentration of Imipenem in Acinetobacter baumannii Strains Isolated From Hospitalized Patients in Shahid Motahari Burn Hospital, Tehran, Iran

    PubMed Central

    Gholami, Mehrdad; Hashemi, Ali; Hakemi-Vala, Mojdeh; Goudarzi, Hossein; Hallajzadeh, Masoumeh

    2015-01-01

    Background: Acinetobacter baumannii has emerged as a highly troublesome pathogen and a leading cause of mortality and morbidity among hospitalized burn patients. Objectives: The aims of this study were to determine the frequency of the AdeABC genes and the role of the efflux pump (s) in the imipenem resistance of A. baumannii strains isolated from burn patients. Materials and Methods: This study was conducted on 60 A. baumannii isolates collected from 240 wound samples of burn patients admitted to the Burn Unit of Shahid Motahari Burn hospital, Tehran, Iran. Antibiotic susceptibility tests were performed using the Kirby-Bauer disc diffusion and broth microdilution according to the clinical and laboratory standards institute (CLSI) guidelines. The activity of the efflux pump was evaluated using the efflux pump inhibitor, the phenylalanine-arginine Β-naphthylamide (PAΒN). The AdeABC genes were detected by polymerase chain reaction (PCR) and sequencing. Results: In this study, 100% of the isolates were resistant to cefotaxime, ceftazidime, ceftriaxone, ciprofloxacin, cefepime, piperacillin, meropenem, co-trimoxazole, and piperacillin/tazobactam; 56 (94%) to gentamicin; 50 (81%) to amikacin; 58 (97%) to imipenem; and 45 (76%) to tetracycline. Additionally,all the isolates were susceptible to colistin. The susceptibility of the strains to imipenem was highly increased in the presence of the efflux pump inhibitor such that for 58 (96.6%) of the isolates, the PAΒN reduced the minimum inhibitory concentrations (MIC) by 4- to 64-fold. The adeA and adeB genes were detected in 60 (100%) of the isolates, and the adeC gene was present in 51 (85%). Conclusions: The efflux pump may play a role in antibiotic resistance in A. baumannii isolates. The ability of A. baumannii isolates to acquire drug resistance by the efflux pump mechanism is a concern. Thus, new strategies are required in order to eliminate the efflux transport activity from resistant A. baumannii isolates causing

  4. Draft Genome Sequences of Nine Pseudomonas aeruginosa Strains, Including Eight Clinical Isolates

    PubMed Central

    Cunningham, Scott A.; Quest, Daniel; Sikkink, Robert A.; O’Brien, Daniel; Eckloff, Bruce W.; Patel, Robin

    2015-01-01

    We report on nine draft genomes of Pseudomonas aeruginosa isolates, assembled using a hybrid paired-end and Nextera mate-pair library approach. Eight are of clinical origin, and one is the ATCC 27853 strain. We also report their multilocus sequence types. PMID:26450729

  5. Deciphering the Multifactorial Nature of Acinetobacter baumannii Pathogenicity

    PubMed Central

    Antunes, Luísa C. S.; Imperi, Francesco; Carattoli, Alessandra; Visca, Paolo

    2011-01-01

    Background Acinetobacter baumannii is an emerging bacterial pathogen that causes a broad array of infections, particularly in hospitalized patients. Many studies have focused on the epidemiology and antibiotic resistance of A. baumannii, but little is currently known with respect to its virulence potential. Methodology/Principal Findings The aim of this work was to analyze a number of virulence-related traits of four A. baumannii strains of different origin and clinical impact for which complete genome sequences were available, in order to tentatively identify novel determinants of A. baumannii pathogenicity. Clinical strains showed comparable virulence in the Galleria mellonella model of infection, irrespective of their status as outbreak or sporadic strains, whereas a non-human isolate was avirulent. A combined approach of genomic and phenotypic analyses led to the identification of several virulence factors, including exoproducts with hemolytic, phospholipase, protease and iron-chelating activities, as well as a number of multifactorial phenotypes, such as biofilm formation, surface motility and stress resistance, which were differentially expressed and could play a role in A. baumannii pathogenicity. Conclusion/Significance This work provides evidence of the multifactorial nature of A. baumannii virulence. While A. baumannii clinical isolates could represent a selected population of strains adapted to infect the human host, subpopulations of highly genotypically and phenotypically diverse A. baumannii strains may exist outside the hospital environment, whose relevance and distribution deserve further investigation. PMID:21829642

  6. Genomic and antigenic characterization of bovine parainfluenze-3 viruses in the United States including modified live virus vaccine (MLV) strains and field strains from cattle

    USDA-ARS?s Scientific Manuscript database

    This study investigated the genetic and antigenic characterization of parainfluenza-3 virus (PI3V) of cattle. Using molecular tests including real time PCR and viral genome sequencing, PI3V strains could be separated into PI3V types, including PI3V A, PI3V B, and PI3V C. Isolates from cattle with bo...

  7. Acinetobacter baumannii neonatal mastitis: a case report.

    PubMed

    Mohr, Emma L; Berhane, Abeba; Zora, John Gregory; Suchdev, Parminder S

    2014-09-25

    Neonatal mastitis is a rare infection. When it does occur, infants younger than 2 months of age are typically affected and the majority of cases are caused by Staphylococcus aureus. We present the first reported case of neonatal mastitis caused by Acinetobacter baumannii, an unusual organism for this type of infection. A 15-day-old full-term Caucasian male neonate presented to our emergency room following fever at home and was admitted for routine neonatal sepsis evaluation. After admission, he developed purulent drainage from his right nipple, was diagnosed with mastitis, and was started on empiric therapy with clindamycin and cefotaxime with presumed coverage for S. aureus. Drainage culture identified pan-susceptible Acinetobacter baumannii/haemolyticus and antibiotic therapy was changed to ceftazidime. He was discharged after 5 days of ceftazidime with complete resolution of his symptoms. This case illustrates the importance of obtaining drainage cultures in mastitis cases because of the possibility of organisms besides S. aureus causing infection. Acinetobacter baumannii is considered part of the normal human flora and is associated with serious infections in intensive care units. This is the first case report describing Acinetobacter baumannii as an etiologic agent of neonatal mastitis and highlights the importance of including unusual organisms in the differential for infectious etiologies for general practitioners.

  8. [Problem of treatment for pyo-inflammatory complications caused by Acinetobacter].

    PubMed

    Bogomolova, N S; Bol'shakov, L V; Kuznetsova, S M

    2014-01-01

    The article deals with analysis of a detection frequency and antibacterial treatment resistance of Acinetobacter spp.of different species affiliation. Strains of bacteria detected in patients with pyo-inflammatory complications after surgeries (period from 2010 to 2012) were involved in the study 137 strains of Acinetobacter spp. were detected and studied Fraction of Acinetobacter spp. in 2010, 2011 and 2012 was 2.3, 3 and 3.4% respectively. Fraction of P. aeruginosain all non-fermentative Gram-negative bacteria (NFGNB) decreased by 120% and fraction of Acinetobacter spp. increased by 200-250%. Acinetobacter spp. detection frequency was not significantly changed in the period from 2006 to 2012. However the fraction of Acinetobacter spp. in NFGNB increased by 150% and was 29% in 2012. Detection frequency of A. baumanii sharply increased in 2012. A study of antibacterial treatment resistance of Acinetobacter spp. (10 antibacterial medicines) showed that Polymyxin B and E (Colistin) was the most effective medicine for A. baumanii and A. calcoaceticus infection. 85-95% of Acinetobacter spp.strains kept sensitivity to this antibacterial medicine. 66-88.9% of A. baumanii strains, 66.7-81.8% of A. alcoaceticus and 66.6% of other Acinetobacter spp. were sensitive to Tigecycline. Dioxidine effectiveness was close to Tigecycline in 66.7-80% of A. baumanii strains. 85-100% of A. calcoaceticus strains were sensitive to Dioxidine. There is a trend of decreasing of A. baumanii sensitivity to Carbapenems by 200%. Fraction of strains sensitive to Meropenem and Imipenem in 2012 was 21.4% and 16.7% respectively. All studied strains of A. lwoffi and A. haemolyticus kept sensitivity to Carbapenems. In 2012 23.8% of A. baumanii and 50% of A. calcoaceticus strains were sensitivity to Amikacin, meanwhile A. lwoffi and A. haemolyticus were not sensitive to this medicine. 31.3% of A. baumanii and 50% of A. calcoaceticus strains were sensitive to Ceftazidime/Sulbactam. 5.3% of A. baumanii

  9. Imipenem: a potent inducer of multidrug resistance in Acinetobacter baumannii.

    PubMed

    Kuo, Han-Yueh; Chang, Kai-Chih; Kuo, Jai-Wei; Yueh, Hui-Wen; Liou, Ming-Li

    2012-01-01

    This study investigated the progression of multidrug resistance upon exposure to imipenem in Acinetobacter baumannii. Eighteen A. baumannii strains, including two reference strains (ATCC 19606 and ATCC 17978), four clinical strains (AB56, AB242, AB273 and AB279) and 12 antibiotic-selected mutant strains, were used in this study. Imipenem-selected mutants were generated from imipenem-susceptible strains (ATCC 19606, ATCC 17978 and AB242) by multistep selection resistance. Amikacin-, ciprofloxacin-, colistin-, meropenem- and ceftazidime-selected mutants were also generated from the two reference strains and were used for comparison. Antibiotic susceptibilities in the absence and presence of the efflux pump inhibitors carbonyl cyanide m-chlorophenylhydrazone (CCCP) and 1-(1-naphthylmethyl)-piperazine (NMP) were examined in the three imipenem-selected mutants and the three clinical multidrug-resistant (MDR) isolates. Expression profiles of the antimicrobial resistance genes in the imipenem-selected mutants and their parental strains were also determined. The results showed that imipenem was more likely, compared with the other antibiotics, to induce a MDR phenotype in the two reference strains. Differences in OXA-51-like carbapenemase, efflux pumps or/and AmpC β-lactamase expression were observed in the three imipenem-selected mutants. Moreover, a reduction in imipenem or amikacin resistance was observed when the imipenem-selected mutants and clinical isolates were exposed to NMP and CCCP. This study concluded that imipenem might be a potent inducer of multidrug resistance in A. baumannii strains. OXA-51-like carbapenemase combined with other resistance mechanisms may contribute to the development of multidrug resistance in A. baumannii. Monitoring the use of carbapenems is required to reduce the spread of MDR A. baumannii in hospitals.

  10. Novel synthetic bis-indolic derivatives with antistaphylococcal activity, including against MRSA and VISA strains.

    PubMed

    Caspar, Yvan; Jeanty, Matthieu; Blu, Jérôme; Burchak, Olga; Le Pihive, Emmanuelle; Maigre, Laure; Schneider, Dominique; Jolivalt, Claude; Paris, Jean-Marc; Hequet, Arnaud; Minassian, Frédéric; Denis, Jean-Noël; Maurin, Max

    2015-01-01

    We report the synthesis, antibacterial activity and toxicity of 24 bis-indolic derivatives obtained during the development of new ways of synthesis of marine bis-indole alkaloids from the spongotine, topsentin and hamacanthin classes. Innovative ways of synthesis and further structural optimizations led to bis-indoles presenting either the 1-(1H-indol-3'-yl)-1,2-diaminoethane unit or the 1-(1H-indol-3-yl)ethanamine unit. MIC determination was performed for reference and clinical strains of Staphylococcus aureus and CoNS species. MBC, time-kill kinetics, solubility, hydrophobicity index, plasma protein-binding and cytotoxicity assays were performed for lead compounds. Inhibition of the S. aureus NorA efflux pump was also tested for bis-indoles with no antistaphylococcal activity. Lead compounds were active against both S. aureus and CoNS species, with MICs between 1 and 4 mg/L. Importantly, the same MICs were found for MRSA and vancomycin-intermediate S. aureus strains. Early concentration-dependent bactericidal activity was observed for lead derivatives. Compounds with no intrinsic antibacterial activity could inhibit the S. aureus NorA efflux pump, which is involved in resistance to fluoroquinolones. At 0.5 mg/L, the most effective compound led to an 8-fold reduction of the ciprofloxacin MIC for the SA-1199B S. aureus strain, which overexpresses NorA. However, the bis-indole compounds displayed a high hydrophobicity index and high plasma protein binding, which significantly reduced antibacterial activity. We have synthesized and characterized novel bis-indole derivatives as promising candidates for the development of new antistaphylococcal treatments, with preserved activity against MDR S. aureus strains. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  11. Occurrence of High Catalase-containing Acinetobacter in Spacecraft Assembly Facilities

    NASA Astrophysics Data System (ADS)

    McCoy, K. B.; Derecho, I.; La Duc, M. T.; Vaishampayan, P.; Venkateswaran, K. J.; Mogul, R.

    2010-04-01

    In summary, the measurement of high catalase specific activity values for spacecraft-associated Acinetobacter strains is potentially the result of adaptation towards the harsh conditions of the clean rooms and assembly process.

  12. Acinetobacter bioreporter assessing heavy metals toxicity.

    PubMed

    Abd-El-Haleem, Desouky; Zaki, Sahar; Abulhamd, Ashraf; Elbery, Hassan; Abu-Elreesh, Gadallah

    2006-01-01

    This work was conducted to employ a whole cell-based biosensor to monitor toxicity of heavy metals in water and wastewater. An isolate of industrial wastewater bacterium, Acinetobacter sp. DF4, was genetically modified with lux reporter gene to create a novel bioluminescent bacterial strain, designated as DF4/PUTK2. This bioreporter can investigate the toxicity through light inhibition due to cell death or metabolic burden and the specific stress effects of the tested soluble materials simultaneously. The use of Acinetobacter DF4/PUTK2 as a bioluminescent reporter for heavy metal toxicity testing and for the application of wastewater treatment influent toxicity screening is presented in this study. Among eight heavy metals tested, the bioluminescence of DF4/PUTK2 was most sensitive to Zn, Cd, Fe, Co, Cr followed by Cu in order of decreasing sensitivity. The same pattern of sensitivity was observed when several contaminated water and wastewater effluents were assayed. This work suggested that luxCDABE -marked Acinetobacter bacterium DF4/PUTK2 can be used to bioassay the ecotoxicity of wastewater and effluent samples contaminated with heavy metals. Using this assay, it is possible to pre-select the more toxic samples for further chemical analysis and to discard wastewater samples with low or no inhibition because they are not toxic to the environment.

  13. Culture and Hybridization Experiments on an Ulva Clade Including the Qingdao Strain Blooming in the Yellow Sea

    PubMed Central

    Hiraoka, Masanori; Ichihara, Kensuke; Zhu, Wenrong; Ma, Jiahai; Shimada, Satoshi

    2011-01-01

    In the summer of 2008, immediately prior to the Beijing Olympics, a massive green tide of the genus Ulva covered the Qingdao coast of the Yellow Sea in China. Based on molecular analyses using the nuclear encoded rDNA internal transcribed spacer (ITS) region, the Qingdao strains dominating the green tide were reported to be included in a single phylogenetic clade, currently regarded as a single species. On the other hand, our detailed phylogenetic analyses of the clade, using a higher resolution DNA marker, suggested that two genetically separate entities could be included within the clade. However, speciation within the Ulva clade has not yet been examined. We examined the occurrence of an intricate speciation within the clade, including the Qingdao strains, via combined studies of culture, hybridization and phylogenetic analysis. The two entities separated by our phylogenetic analyses of the clade were simply distinguished as U. linza and U. prolifera morphologically by the absence or presence of branches in cultured thalli. The inclusion of sexual strains and several asexual strains were found in each taxon. Hybridizations among the sexual strains also supported the separation by a partial gamete incompatibility. The sexually reproducing Qingdao strains crossed with U. prolifera without any reproductive boundary, but a complete reproductive isolation to U. linza occurred by gamete incompatibility. The results demonstrate that the U. prolifera group includes two types of sexual strains distinguishable by crossing affinity to U. linza. Species identification within the Ulva clade requires high resolution DNA markers and/or hybridization experiments and is not possible by reliance on the ITS markers alone. PMID:21573216

  14. Isolation of Clostridium difficile from dogs with digestive disorders, including stable metronidazole-resistant strains.

    PubMed

    Orden, Cristina; Blanco, Jose L; Álvarez-Pérez, Sergio; Garcia-Sancho, Mercedes; Rodriguez-Franco, Fernando; Sainz, Angel; Villaescusa, Alejandra; Harmanus, Celine; Kuijper, Ed; Garcia, Marta E

    2017-02-01

    The prevalence of Clostridium difficile in 107 dogs with diverse digestive disorders attended in a Spanish veterinary teaching hospital was assessed. The microorganism was isolated from 13 dogs (12.1%) of different disease groups. Isolates belonged to PCR ribotypes 078, 106, 154 and 430 (all of them toxigenic) and 110 (non-toxigenic), and were resistant to several antimicrobial drugs. Notably, seven isolates obtained from different dogs displayed stable resistance to metronidazole. The results of this study provide further evidence that dogs can act as a reservoir of C. difficile strains of epidemic ribotypes with resistance to multiple antibiotics.

  15. The Genomic Diversification of the Whole Acinetobacter Genus: Origins, Mechanisms, and Consequences

    PubMed Central

    Touchon, Marie; Cury, Jean; Yoon, Eun-Jeong; Krizova, Lenka; Cerqueira, Gustavo C.; Murphy, Cheryl; Feldgarden, Michael; Wortman, Jennifer; Clermont, Dominique; Lambert, Thierry; Grillot-Courvalin, Catherine; Nemec, Alexandr; Courvalin, Patrice; Rocha, Eduardo P.C.

    2014-01-01

    Bacterial genomics has greatly expanded our understanding of microdiversification patterns within a species, but analyses at higher taxonomical levels are necessary to understand and predict the independent rise of pathogens in a genus. We have sampled, sequenced, and assessed the diversity of genomes of validly named and tentative species of the Acinetobacter genus, a clade including major nosocomial pathogens and biotechnologically important species. We inferred a robust global phylogeny and delimited several new putative species. The genus is very ancient and extremely diverse: Genomes of highly divergent species share more orthologs than certain strains within a species. We systematically characterized elements and mechanisms driving genome diversification, such as conjugative elements, insertion sequences, and natural transformation. We found many error-prone polymerases that may play a role in resistance to toxins, antibiotics, and in the generation of genetic variation. Surprisingly, temperate phages, poorly studied in Acinetobacter, were found to account for a significant fraction of most genomes. Accordingly, many genomes encode clustered regularly interspaced short palindromic repeats (CRISPR)-Cas systems with some of the largest CRISPR-arrays found so far in bacteria. Integrons are strongly overrepresented in Acinetobacter baumannii, which correlates with its frequent resistance to antibiotics. Our data suggest that A. baumannii arose from an ancient population bottleneck followed by population expansion under strong purifying selection. The outstanding diversification of the species occurred largely by horizontal transfer, including some allelic recombination, at specific hotspots preferentially located close to the replication terminus. Our work sets a quantitative basis to understand the diversification of Acinetobacter into emerging resistant and versatile pathogens. PMID:25313016

  16. Diversity and clinical impact of Acinetobacter baumannii colonization and infection at a military medical center.

    PubMed

    Petersen, Kyle; Cannegieter, Suzanne C; van der Reijden, Tanny J; van Strijen, Beppie; You, David M; Babel, Britta S; Philip, Andrew I; Dijkshoorn, Lenie

    2011-01-01

    The epidemiology of Acinetobacter baumannii emerging in combat casualties is poorly understood. We analyzed 65 (54 nonreplicate) Acinetobacter isolates from 48 patients (46 hospitalized and 2 outpatient trainees entering the military) from October 2004 to October 2005 for genotypic similarities, time-space relatedness, and antibiotic susceptibility. Clinical and surveillance cultures were compared by amplified fragment length polymorphism (AFLP) genomic fingerprinting to each other and to strains of a reference database. Antibiotic susceptibility was determined, and multiplex PCR was performed for OXA-23-like, -24-like, -51-like, and -58-like carbapenemases. Records were reviewed for overlapping hospital stays of the most frequent genotypes, and risk ratios were calculated for any association of genotype with severity of Acute Physiology and Chronic Health Evaluation II (APACHE II) score or injury severity score (ISS) and previous antibiotic use. Nineteen genotypes were identified; two predominated, one consistent with an emerging novel international clone and the other unique to our database. Both predominant genotypes were carbapenem resistant, were present at another hospital before patients' admission to our facility, and were associated with higher APACHE II scores, higher ISSs, and previous carbapenem antibiotics in comparison with other genotypes. One predominated in wound and respiratory isolates, and the other predominated in wound and skin surveillance samples. Several other genotypes were identified as European clones I to III. Acinetobacter genotypes from recruits upon entry to the military, unlike those in hospitalized patients, did not include carbapenem-resistant genotypes. Acinetobacter species isolated from battlefield casualties are diverse, including genotypes belonging to European clones I to III. Two carbapenem-resistant genotypes were epidemic, one of which appeared to belong to a novel international clone.

  17. The genomic diversification of the whole Acinetobacter genus: origins, mechanisms, and consequences.

    PubMed

    Touchon, Marie; Cury, Jean; Yoon, Eun-Jeong; Krizova, Lenka; Cerqueira, Gustavo C; Murphy, Cheryl; Feldgarden, Michael; Wortman, Jennifer; Clermont, Dominique; Lambert, Thierry; Grillot-Courvalin, Catherine; Nemec, Alexandr; Courvalin, Patrice; Rocha, Eduardo P C

    2014-10-13

    Bacterial genomics has greatly expanded our understanding of microdiversification patterns within a species, but analyses at higher taxonomical levels are necessary to understand and predict the independent rise of pathogens in a genus. We have sampled, sequenced, and assessed the diversity of genomes of validly named and tentative species of the Acinetobacter genus, a clade including major nosocomial pathogens and biotechnologically important species. We inferred a robust global phylogeny and delimited several new putative species. The genus is very ancient and extremely diverse: Genomes of highly divergent species share more orthologs than certain strains within a species. We systematically characterized elements and mechanisms driving genome diversification, such as conjugative elements, insertion sequences, and natural transformation. We found many error-prone polymerases that may play a role in resistance to toxins, antibiotics, and in the generation of genetic variation. Surprisingly, temperate phages, poorly studied in Acinetobacter, were found to account for a significant fraction of most genomes. Accordingly, many genomes encode clustered regularly interspaced short palindromic repeats (CRISPR)-Cas systems with some of the largest CRISPR-arrays found so far in bacteria. Integrons are strongly overrepresented in Acinetobacter baumannii, which correlates with its frequent resistance to antibiotics. Our data suggest that A. baumannii arose from an ancient population bottleneck followed by population expansion under strong purifying selection. The outstanding diversification of the species occurred largely by horizontal transfer, including some allelic recombination, at specific hotspots preferentially located close to the replication terminus. Our work sets a quantitative basis to understand the diversification of Acinetobacter into emerging resistant and versatile pathogens.

  18. Diversity and Clinical Impact of Acinetobacter baumannii Colonization and Infection at a Military Medical Center ▿

    PubMed Central

    Petersen, Kyle; Cannegieter, Suzanne C.; van der Reijden, Tanny J.; van Strijen, Beppie; You, David M.; Babel, Britta S.; Philip, Andrew I.; Dijkshoorn, Lenie

    2011-01-01

    The epidemiology of Acinetobacter baumannii emerging in combat casualties is poorly understood. We analyzed 65 (54 nonreplicate) Acinetobacter isolates from 48 patients (46 hospitalized and 2 outpatient trainees entering the military) from October 2004 to October 2005 for genotypic similarities, time-space relatedness, and antibiotic susceptibility. Clinical and surveillance cultures were compared by amplified fragment length polymorphism (AFLP) genomic fingerprinting to each other and to strains of a reference database. Antibiotic susceptibility was determined, and multiplex PCR was performed for OXA-23-like, -24-like, -51-like, and -58-like carbapenemases. Records were reviewed for overlapping hospital stays of the most frequent genotypes, and risk ratios were calculated for any association of genotype with severity of Acute Physiology and Chronic Health Evaluation II (APACHE II) score or injury severity score (ISS) and previous antibiotic use. Nineteen genotypes were identified; two predominated, one consistent with an emerging novel international clone and the other unique to our database. Both predominant genotypes were carbapenem resistant, were present at another hospital before patients' admission to our facility, and were associated with higher APACHE II scores, higher ISSs, and previous carbapenem antibiotics in comparison with other genotypes. One predominated in wound and respiratory isolates, and the other predominated in wound and skin surveillance samples. Several other genotypes were identified as European clones I to III. Acinetobacter genotypes from recruits upon entry to the military, unlike those in hospitalized patients, did not include carbapenem-resistant genotypes. Acinetobacter species isolated from battlefield casualties are diverse, including genotypes belonging to European clones I to III. Two carbapenem-resistant genotypes were epidemic, one of which appeared to belong to a novel international clone. PMID:21084513

  19. Nanoparticles for Control of Biofilms of Acinetobacter Species

    PubMed Central

    Singh, Richa; Nadhe, Shradhda; Wadhwani, Sweety; Shedbalkar, Utkarsha; Chopade, Balu Ananda

    2016-01-01

    Biofilms are the cause of 80% of microbial infections. Acinetobacter species have emerged as multi- and pan-drug-resistant bacteria and pose a great threat to human health. These act as nosocomial pathogens and form excellent biofilms, both on biotic and abiotic surfaces, leading to severe infections and diseases. Various methods have been developed for treatment and control of Acinetobacter biofilm including photodynamic therapy, radioimmunotherapy, prophylactic vaccines and antimicrobial peptides. Nanotechnology, in the present scenario, offers a promising alternative. Nanomaterials possess unique properties, and multiple bactericidal mechanisms render them more effective than conventional drugs. This review intends to provide an overview of Acinetobacter biofilm and the significant role of various nanoparticles as anti-biofouling agents, surface-coating materials and drug-delivery vehicles for biofilm control and treatment of Acinetobacter infections. PMID:28773507

  20. Kinetics of the enzyme-vesicle interaction including the formation of rafts and membrane strain.

    PubMed

    Zhdanov, Vladimir P; Höök, Fredrik

    2012-01-01

    In cells, an appreciable part of enzymes is associated with lipid membranes. Academic experimental studies of the function of membrane enzymes (e.g., PLA(2) representing a prototype for interfacial enzymology) are often focused on the enzyme-vesicle interaction or, more specifically, on conversion of lipid forming the external leaflet of the vesicle membrane. The corresponding kinetics are complicated by many factors inherent to the interfacial physics and chemistry. The understanding of the relative role of such factors and how they should be quantitatively described is still limited. Here, we present the mean-field kinetic equations, taking the formation of rafts in the membrane and the product-induced membrane strain into account, and analyze various scenarios of lipid conversion. In particular, we scrutinize the conditions when the kinetics may exhibit a transition from a relatively long latency period to a steady-state regime with fast nearly constant reaction rate. Specifically, we discuss the likely role of the pore formation in the external lipid layer in this transition. The latter effect may be caused by the product-induced tensile strain in this layer.

  1. Acinetobacter plantarum sp. nov. isolated from wheat seedlings plant.

    PubMed

    Du, Juan; Singh, Hina; Yu, Hongshan; Jin, Feng-Xie; Yi, Tae-Hoo

    2016-07-01

    Strain THG-SQM11(T), a Gram-negative, aerobic, non-motile, coccus-shaped bacterium, was isolated from wheat seedlings plant in P. R. China. Strain THG-SQM11(T) was closely related to members of the genus Acinetobacter and showed the highest 16S rRNA sequence similarities with Acinetobacter junii (97.9 %) and Acinetobacter kookii (96.1 %). DNA-DNA hybridization showed 41.3 ± 2.4 % DNA reassociation with A. junii KCTC 12416(T). Chemotaxonomic data revealed that strain THG-SQM11(T) possesses ubiquinone-9 as the predominant respiratory quinone, C18:1 ω9c, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), and C16:0 as the major fatty acids. The major polar lipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylcholine. The DNA G+C content was 41.7 mol %. These data, together with phenotypic characterization, suggest that the isolate represents a novel species, for which the name Acinetobacter plantarum sp. nov. is proposed, with THG-SQM11(T) as the type strain (=CCTCC AB 2015123(T) =KCTC 42611(T)).

  2. Multidrug-Resistant Acinetobacter baumannii in Veterinary Clinics, Germany

    PubMed Central

    Prenger-Berninghoff, Ellen; Weiss, Reinhard; van der Reijden, Tanny; van den Broek, Peterhans; Baljer, Georg; Dijkshoorn, Lenie

    2011-01-01

    An increase in prevalence of multidrug-resistant Acinetobacter spp. in hospitalized animals was observed at the Justus-Liebig-University (Germany). Genotypic analysis of 56 isolates during 2000–2008 showed 3 clusters that corresponded to European clones I–III. Results indicate spread of genotypically related strains within and among veterinary clinics in Germany. PMID:21888812

  3. In Vitro Antimicrobial Activity of a Siderophore Cephalosporin, S-649266, against Enterobacteriaceae Clinical Isolates, Including Carbapenem-Resistant Strains

    PubMed Central

    West, Joshua; Ito, Akinobu; Ito-Horiyama, Tsukasa; Nakamura, Rio; Sato, Takafumi; Rittenhouse, Stephen; Tsuji, Masakatsu; Yamano, Yoshinori

    2015-01-01

    S-649266 is a novel siderophore cephalosporin antibiotic with a catechol moiety on the 3-position side chain. Two sets of clinical isolate collections were used to evaluate the antimicrobial activity of S-649266 against Enterobacteriaceae. These sets included 617 global isolates collected between 2009 and 2011 and 233 β-lactamase-identified isolates, including 47 KPC-, 49 NDM-, 12 VIM-, and 8 IMP-producers. The MIC90 values of S-649266 against the first set of Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Citrobacter freundii, Enterobacter aerogenes, and Enterobacter cloacae isolates were all ≤1 μg/ml, and there were only 8 isolates (1.3%) among these 617 clinical isolates with MIC values of ≥8 μg/ml. In the second set, the MIC values of S-649266 were ≤4 μg/ml against 109 strains among 116 KPC-producing and class B (metallo) carbapenemase-producing strains. In addition, S-649266 showed MIC values of ≤2 μg/ml against each of the 13 strains that produced other types of carbapenemases such as SME, NMC, and OXA-48. The mechanisms of the decreased susceptibility of 7 class B carbapenemase-producing strains with MIC values of ≥16 μg/ml are uncertain. This is the first report to demonstrate that S-649266, a novel siderophore cephalosporin, has significant antimicrobial activity against Enterobacteriaceae, including strains that produce carbapenemases such as KPC and NDM-1. PMID:26574013

  4. Acinetobacter bohemicus sp. nov. widespread in natural soil and water ecosystems in the Czech Republic.

    PubMed

    Krizova, Lenka; Maixnerova, Martina; Sedo, Ondrej; Nemec, Alexandr

    2014-10-01

    We investigated the taxonomic status of a phenetically unique group of 25 Acinetobacter strains which were isolated from multiple soil and water samples collected in natural ecosystems in the Czech Republic. Based on the comparative sequence analyses of the rpoB, gyrB, and 16S rRNA genes, the strains formed a coherent and well separated branch within the genus Acinetobacter. The genomic uniqueness of the group at the species level was supported by the low average nucleotide identity values (≤77.37%) between the whole genome sequences of strain ANC 3994(T) (NCBI accession no. APOH00000000) and the representatives of the known Acinetobacter species. Moreover, all 25 strains created a tight cluster clearly separated from all hitherto described species based on whole-cell protein profiling by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and shared a unique combination of metabolic and physiological properties. The capacity to assimilate l-histidine and the inability to grow at 35°C differentiated them from their phenotypically closest neighbor, Acinetobacter johnsonii. We conclude that the 25 strains represent a novel Acinetobacter species, for which the name Acinetobacter bohemicus sp. nov. is proposed. The type strain of A. bohemicus is ANC 3994(T) (=CIP 110496(T)=CCUG 63842(T)=CCM 8462(T)).

  5. Emergence of carbapenem non-susceptible multidrug resistant Acinetobacter baumannii strains of clonal complexes 103(B) and 92(B) harboring OXA-type carbapenemases and metallo-β-lactamases in Southern India.

    PubMed

    Saranathan, Rajagopalan; Vasanth, Vaidyanathan; Vasanth, Thamodharan; Shabareesh, Pidathala Raghavendra Venkata; Shashikala, P; Devi, Chandrakesan Sheela; Kalaivani, Ramakrishnan; Asir, Johny; Sudhakar, Pagal; Prashanth, K

    2015-05-01

    The molecular epidemiology and carbapenem resistance mechanisms of clinical isolates of Acinetobacter baumannii obtained from a south Indian tertiary care hospital were investigated by repetitive extragenic palindromic sequence PCR (REP-PCR) and multi-locus sequence typing (MLST). Analysis of resistant determinants was achieved by PCR screening for the presence of genes encoding OXA-carbapenemases, metallo-β-lactamases (MBLs) and efflux pumps. REP-PCR generated around eight clusters of high heterogeneity; of these, two major clusters (I and V) appeared to be clonal in origin. Analysis of representative isolates from different clusters by MLST revealed that most of the isolates belonged to sequence type 103 of CC103(B) . Second most prevalent ST belonged to clonal complex (CC) 92(B) which is also referred to as international clone II. Most of the isolates were multi-drug resistant, being susceptible only to polymyxin-B and newer quinolones. Class D β-lactamases such as blaOXA-51-like (100%), blaOXA-23-like (56.8%) and blaOXA-24-like (14.8%) were found to be predominant, followed by a class B β-lactamase, namely blaIMP-1 (40.7%); none of the isolates had blaOXA-58 like, blaNDM-1 or blaSIM-1 . Genes of efflux-pump adeABC were predominant, most of isolates being biofilm producers that were PCR-positive for autoinducer synthase gene (>94%). Carbapenem non-susceptible isolates were highly diverse and present throughout the hospital irrespective of type of ward or intensive care unit. Although previous reports have documented diverse resistant mechanisms in A. baumannii, production of MBL and OXA-type of carbapenamases were found to be the predominant mechanism(s) of carbapenem resistance identified in strains isolated from Southern India.

  6. Acinetobacter baumannii: an emerging opportunistic pathogen.

    PubMed

    Howard, Aoife; O'Donoghue, Michael; Feeney, Audrey; Sleator, Roy D

    2012-05-01

    Acinetobacter baumannii is an opportunistic bacterial pathogen primarily associated with hospital-acquired infections. The recent increase in incidence, largely associated with infected combat troops returning from conflict zones, coupled with a dramatic increase in the incidence of multidrug-resistant (MDR) strains, has significantly raised the profile of this emerging opportunistic pathogen. Herein, we provide an overview of the pathogen, discuss some of the major factors that have led to its clinical prominence and outline some of the novel therapeutic strategies currently in development.

  7. First Identification and Characterization of an AdeABC-Like Efflux Pump in Acinetobacter Genomospecies 13TU▿ †

    PubMed Central

    Roca, Ignasi; Espinal, Paula; Martí, Sara; Vila, Jordi

    2011-01-01

    Non-Acinetobacter baumannii spp. are emerging among clinical Acinetobacter isolates causing nosocomial infections, and some (such as genomospecies 13TU) appear to be multidrug resistant. The prevalence of non-Acinetobacter baumannii spp. in the hospital setting is likely understated due to poor identification techniques. We report the first identification of an AdeABC-type efflux pump in an Acinetobacter genomospecies 13TU clinical isolate, its contribution to multidrug resistance, and the coexistence of three Ade-type efflux pumps in this strain. PMID:21199925

  8. Combined therapy for multi-drug-resistant Acinetobacter baumannii infection--is there evidence outside the laboratory?

    PubMed

    Tuon, Felipe F; Rocha, Jaime L; Merlini, Alexandre B

    2015-09-01

    Acinetobacter are among the most common bacteria isolated in hospital infections, especially in developing countries. Multi-drug, extended-drug or pan-drug resistance makes treatment a real medical challenge. In the present review, the authors describe clinical and experimental data in order to present different current and potential future strategies to treat infections caused by multi-drug-resistant Acinetobacter. The therapeutic options for carbapenem-resistant Acinetobacter are scarce, and the current options have poor pharmacokinetic aspects and several side effects. Combined therapy has been an alternative for multi-drug-resistant Acinetobacter. However, this issue is always controversial. In some studies combined therapy has shown superiority for some strains of Acinetobacter in animal models and in vitro studies. However, studies with humans are scarce and too poor quality to suggest the best approach for the treatment of infections caused by multi-drug-resistant Acinetobacter baumannii.

  9. Screening of antibiotics resistance to Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii by an advanced expert system.

    PubMed

    Nakamura, Tatsuya; Takahashi, Hakuo

    2005-12-01

    The VITEK2 advanced expert system (AES) gives information about the antibiotics-resistance mechanisms based on the biological validation derived from the VITEK2 susceptibility result. In this study, we investigated whether or not this system correctly categorized the beta-lactamase resistance mechanism data derived from the VITEK2 susceptibility result using the testing card, AST-N025, with Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii. We used 131 strains, and their phenotypes were determined according to the biological and genetic screening. The AES analysis result matched the phenotype testing in 120 (91.6%) of the 131 strains. Incorrect findings were found in six strains, including three strains of Serratia marcescens. The resistance mechanism could not be determined in five strains, including three strains of Providencia rettgeri. The analysis of those phenotypes agreed in 34 (97.1%) among 35 strains with extended spectrum beta-lactamase (ESBL), and in 27 (96.4%) among 28 strains with high-level cephalosporinase. The agreement ratio in the phenotype was very high as we expected. The incorrect and nondeterminable samples were strains with relatively high cephalosporinase that has variation of outer membrane protein. The AES was able to detect the phenotype for carbapenemase. The AES is a clinically useful system that allows taking prompt measures to treat patients because it can provide information about the resistance mechanism in less than half a day after starting the analysis.

  10. First report of OXA-72 producing Acinetobacter baumannii in Romania.

    PubMed

    Georgescu, M; Gheorghe, I; Dudu, A; Czobor, I; Costache, M; Cristea, V-C; Lazăr, V; Chifiriuc, M C

    2016-09-01

    This is the first report of an OXA-72-producing Acinetobacter baumannii strain in Romania, isolated from chronic leg ulcer samples. Identification of the strain was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Presence of carbapenem resistance genes was investigated by PCR and sequencing. Our data support the spread of the bla OXA-72 gene in Eastern Europe.

  11. Characterization of hydrogen peroxide-resistant Acinetobacter species isolated during the Mars Phoenix spacecraft assembly.

    PubMed

    Derecho, I; McCoy, K B; Vaishampayan, P; Venkateswaran, K; Mogul, R

    2014-10-01

    The microbiological inventory of spacecraft and the associated assembly facility surfaces represent the primary pool of forward contaminants that may impact the integrity of life-detection missions. Herein, we report on the characterization of several strains of hydrogen peroxide-resistant Acinetobacter, which were isolated during the Mars Phoenix lander assembly. All Phoenix-associated Acinetobacter strains possessed very high catalase specific activities, and the specific strain, A. gyllenbergii 2P01AA, displayed a survival against hydrogen peroxide (no loss in 100 mM H2O2 for 1 h) that is perhaps the highest known among Gram-negative and non-spore-forming bacteria. Proteomic characterizations reveal a survival mechanism inclusive of proteins coupled to peroxide degradation (catalase and alkyl hydroperoxide reductase), energy/redox management (dihydrolipoamide dehydrogenase), protein synthesis/folding (EF-G, EF-Ts, peptidyl-tRNA hydrolase, DnaK), membrane functions (OmpA-like protein and ABC transporter-related protein), and nucleotide metabolism (HIT family hydrolase). Together, these survivability and biochemical parameters support the hypothesis that oxidative tolerance and the related biochemical features are the measurable phenotypes or outcomes for microbial survival in the spacecraft assembly facilities, where the low-humidity (desiccation) and clean (low-nutrient) conditions may serve as selective pressures. Hence, the spacecraft-associated Acinetobacter, due to the conferred oxidative tolerances, may ultimately hinder efforts to reduce spacecraft bioburden when using chemical sterilants, thus suggesting that non-spore-forming bacteria may need to be included in the bioburden accounting for future life-detection missions.

  12. Insight into norfloxacin resistance of Acinetobacter oleivorans DR1: target gene mutation, persister, and RNA-Seq analyses.

    PubMed

    Kim, Jisun; Noh, Jaemin; Park, Woojun

    2013-09-28

    Antibiotic resistance of soilborne Acinetobacter species has been poorly explored. In this study, norfloxacin resistance of a soil bacterium, Acinetobacter oleivorans DR1, was investigated. The frequencies of mutant appearance of all tested non-pathogenic Acinetobacter strains were lower than those of pathogenic strains under minimum inhibitory concentration (MIC). When the quinolone-resistance-determining region of the gyrA gene was examined, only one mutant (His78Asn) out of 10 resistant variants had a mutation. Whole transcriptome analysis using a RNA-Seq demonstrated that genes involved in SOS response and DNA repair were significantly up-regulated by norfloxacin. Determining the MICs of survival cells after norfloxacin treatment confirmed some of those cells were indeed persister cells. Ten colonies, randomly selected from among those that survived in the presence of norfloxacin, did not exhibit increased MIC. Thus, both the low mutation frequency of the target gene and SOS response under norfloxacin suggested that persister formation might contribute to the resistance of DR1 against norfloxacin. The persister frequency increased without a change in MIC when stationary phase cells, low growth rates conditions, and growth-deficient dnaJ mutant were used. Taken together, our comprehensive approach, which included mutational analysis of the target gene, persister formation assays, and RNA sequencing, indicated that DR1 survival when exposed to norfloxacin is related not only to target gene mutation but also to persister formation, possibly through up-regulation of the SOS response and DNA repair genes.

  13. Identification of Genomic Species of Acinetobacter Isolated from Burns of ICU Patients.

    PubMed

    Shaykh Baygloo, Nima; Bouzari, Majid; Rahimi, Fateh; Abedini, Fereydoon; Yadegari, Sima; Soroushnia, Mohsen; Beigi, Fahimeh

    2015-10-01

    The worldwide emergence of multi-drug resistant (MDR) bacteria in recent years has caused many problems for hospitals and patients, especially intensive care unit patients. Among these clinically important MDR bacteria are Acinetobacter baumannii complex species (A. baumannii, Acinetobacter genomic species 3 and Acinetobacter genomic species 13TU) that cause a wide range of infections. The sequencing and bioinformatics analysis of a part of the Zone 1 of rpoB gene was performed for species identification of Acinetobacter isolates obtained from ICU patients with infected burns hospitalized in a hospital in Isfahan, Iran, over a 9-month period. Antibiotic sensitivity of Acinetobacter isolates was investigated using the disk diffusion method and different classes of antibiotics including amikacin, cefotaxime, ceftriaxone, ciprofloxacin, imipenem and piperacillin. Acinetobacter spp. were isolated from 10 of 80 (12.5%) investigated patients. All of the 10 Acinetobacter isolates were identified as Acinetobacter baumannii and multi-drug resistant according to antibiotic susceptibility tests. Of the Acinetobacter baumannii complex members, only A. baumannii species was identified among the isolates obtained from patients with infected burns in an Isfahan hospital over a 9-month period.

  14. Improved Triacylglycerol Production in Acinetobacter baylyi ADP1 by Metabolic Engineering

    PubMed Central

    2011-01-01

    Background Triacylglycerols are used in various purposes including food applications, cosmetics, oleochemicals and biofuels. Currently the main sources for triacylglycerol are vegetable oils, and microbial triacylglycerol has been suggested as an alternative for these. Due to the low production rates and yields of microbial processes, the role of metabolic engineering has become more significant. As a robust model organism for genetic and metabolic studies, and for the natural capability to produce triacylglycerol, Acinetobacter baylyi ADP1 serves as an excellent organism for modelling the effects of metabolic engineering for energy molecule biosynthesis. Results Beneficial gene deletions regarding triacylglycerol production were screened by computational means exploiting the metabolic model of ADP1. Four deletions, acr1, poxB, dgkA, and a triacylglycerol lipase were chosen to be studied experimentally both separately and concurrently by constructing a knock-out strain (MT) with three of the deletions. Improvements in triacylglycerol production were observed: the strain MT produced 5.6 fold more triacylglycerol (mg/g cell dry weight) compared to the wild type strain, and the proportion of triacylglycerol in total lipids was increased by 8-fold. Conclusions In silico predictions of beneficial gene deletions were verified experimentally. The chosen single and multiple gene deletions affected beneficially the natural triacylglycerol metabolism of A. baylyi ADP1. This study demonstrates the importance of single gene deletions in triacylglycerol metabolism, and proposes Acinetobacter sp. ADP1 as a model system for bioenergetic studies regarding metabolic engineering. PMID:21592360

  15. Purification and characterization of novel extracellular cholesterol esterase from Acinetobacter sp.

    PubMed

    Du, Liangjun; Huo, Ying; Ge, Fanglan; Yu, Jiajun; Li, Wei; Cheng, Guiying; Yong, Bin; Zeng, Lihuang; Huang, Min

    2010-12-01

    CHE4-1, a bacterial strain that belongs to the genus Acinetobacter and expresses high level of inducible extracellular cholesterol esterase (CHE), was isolated from feces of carnivore Panthera pardus var. The cholesterol esterase of the strain CHE4-1 was purified by ultrafiltration followed with DEAE-Sepharose FF chromatography and Phenyl-Sepharose CL-4B chromatography, and then by Sephadex G-50 gel filtration. Different from other known microbial cholesterol esterase, the purified CHE from CHE4-1 strain is a monomer with molecular weight of 6.5 kD and has high activity to both long-chain and short-chain cholesterol ester. Enzymatic activity was enhanced in the presence of metal ion Ca(2+), Zn(2+) and boracic acid, and was not significantly affected by several detergents including sodium cholate, Triton X100 and Tween-80. The enzyme was found to be stable during long-term aqueous storage at 4 °C, indicating its potential as a clinical diagnostic reagent. To the best of our knowledge, this is the first report regarding purification and characterization of CHE from Acinetobacter sp. The results demonstrated that this particular CHE is a novel cholesterol esterase.

  16. Acinetobacter lactucae sp. nov., isolated from iceberg lettuce (Asteraceae: Lactuca sativa).

    PubMed

    Rooney, Alejandro P; Dunlap, Christopher A; Flor-Weiler, Lina B

    2016-09-01

    Strain NRRL B-41902T and three closely related strains were isolated from iceberg lettuce. The strain was found to consist of strictly aerobic, Gram-stain-negative rods that formed cocci in late stationary phase. 16S rRNA gene sequence analysis showed that strain NRRL B-41902T was most closely related to species within the genera Acinetobacter, and that a grouping of it and the three other closely related strains was most closely related to the type strain of Acinetobacter pittii, which was also confirmed through a phylogenomic analysis. Moreover, in silico DNA-DNA hybridization analysis revealed a substantial amount of genomic divergence (39.1 %) between strain NRRL B-41902T and the type strain of A. pittii, which is expected if the strains represent distinct species. Further phenotypic analysis revealed that strain NRRL B-41902T was able to utilize a combination of l-serine, citraconic acid and citramalic acid, which differentiated it from other, closely related Acinetobacter species. Therefore, strain NRRL B-41902T (=CCUG 68785T) is proposed as the type strain of a novel species, Acinetobacter lactucae sp. nov.

  17. Genomic analysis of influenza A viruses, including avian flu (H5N1) strains.

    PubMed

    Ahn, Insung; Jeong, Byeong-Jin; Bae, Se-Eun; Jung, Jin; Son, Hyeon S

    2006-01-01

    This study was designed to conduct genomic analysis in two steps, such as the overall relative synonymous codon usage (RSCU) analysis of the five virus species in the orthomyxoviridae family, and more intensive pattern analysis of the four subtypes of influenza A virus (H1N1, H2N2, H3N2, and H5N1) which were isolated from human population. All the subtypes were categorized by their isolated regions, including Asia, Europe, and Africa, and most of the synonymous codon usage patterns were analyzed by correspondence analysis (CA). As a result, influenza A virus showed the lowest synonymous codon usage bias among the virus species of the orthomyxoviridae family, and influenza B and influenza C virus were followed, while suggesting that influenza A virus might have an advantage in transmitting across the species barrier due to their low codon usage bias. The ENC values of the host-specific HA and NA genes represented their different HA and NA types very well, and this reveals that each influenza A virus subtype uses different codon usage patterns as well as the amino acid compositions. In NP, PA and PB2 genes, most of the virus subtypes showed similar RSCU patterns except for H5N1 and H3N2 (A/HK/1774/1999) subtypes which were suspected to be transmitted across the species barrier, from avian and porcine species to human beings, respectively. This distinguishable synonymous codon usage patterns in non-human origin viruses might be useful in determining the origin of influenza A viruses in genomic levels as well as the serological tests. In this study, all the process, including extracting sequences from GenBank flat file and calculating codon usage values, was conducted by Java codes, and these bioinformatics-related methods may be useful in predicting the evolutionary patterns of pandemic viruses.

  18. [In vitro tigecycline and carbapenem susceptibilities of clinical Acinetobacter baumannii isolates].

    PubMed

    Nayman Alpat, Saygın; Aybey, Aşkın Derya; Akşit, Filiz; Ozgüneş, Ilhan; Kiremitçi, Abdurrahman; Usluer, Gaye

    2010-10-01

    Acinetobacter baumannii is a frequent cause of nosocomial infections in most hospitals. Management of infections caused by these strains is difficult, as the strains often display multiple drug resistance, including carbapenem. Tigecycline which is a glycylcycline derivative has antimicrobial activity against many gram-positive and gram-negative organisms. In this study, in vitro activity of tigecycline and carbapenems against clinical isolates of A.baumannii strains were investigated. A total of 100 A.baumannii isolates were collected from hospitalized patients with documented nosocomial infections [pneumonia (n = 39), surgical wound infection (n = 32), bacteremia (n = 16), catheter infection (n = 6), urinary tract infection (n = 5), peritonitis (n = 1), eye infection (n = 1)] between October 2006 and June 2007. Only one isolate per patient was included to the study. Minimum inhibitory concentrations (MIC) of tigecycline were determined by E-test (AB Biodisk, Sweden). Carbapenem resistance of A.baumannii strains were determined by disk diffusion method. All of the 100 A.baumannii isolates (100%) were found susceptible to tigecycline (MIC values ≤ 2 µg/ml; MIC ranges: 0.032-1.5 µg/ml). Imipenem susceptibility test was performed for 95 strains, and 36 (37.9%) were found sensitive, 18 (18.9%) were intermediate sensitive, and 41 (43.2%) were resistant. Meropenem susceptibility test was performed for 87 strains, and 22 (25.3%) were found sensitive, 9 (10.3%) were intermediate sensitive, and 56 (64.4%) were resistant. Since tigecycline is found quite effective on nosocomial A.baumannii isolates, it may be considered as a treatment alternative in infections caused by carbapenem-resistant Acinetobacter spp.

  19. The first cases of human bacteremia caused by Acinetobacter seifertii in Japan.

    PubMed

    Kishii, Kozue; Kikuchi, Ken; Tomida, Junko; Kawamura, Yoshiaki; Yoshida, Atsushi; Okuzumi, Katsuko; Moriya, Kyoji

    2016-05-01

    Acinetobacter seifertii, a novel species of Acinetobacter, was first reported in 2015. A. seifertii strains were isolated from human clinical specimens (blood, respiratory tract, and ulcer) and hospital environments. Here, we report the first cases of bacteremia caused by A. seifertii in patients with catheter-related bloodstream infection in Japan. The patients favorably recovered, without any complications, after removal of the peripheral intravenous catheters and administration of antibiotics. The pathogens were initially identified as Acinetobacter baumannii, using phenotypic methods and the MicroScan Walkaway System; however, rpoB gene sequence analysis indicated 99.54% similarity to A. seifertii. Moreover, antimicrobial susceptibility testing revealed that one of the strains was not susceptible to gentamicin and ceftazidime. Our report shows that Acinetobacter species other than A. baumannii can also cause nosocomial infections and that accurate methods for the identification of causative agents should be developed.

  20. Carbapenem-resistance and pathogenicity of bovine Acinetobacter indicus-like isolates

    PubMed Central

    Leidner, Ursula; Semmler, Torsten; Scheufen, Sandra; Ewers, Christa

    2017-01-01

    The objective of this study was to characterize blaOXA-23 harbouring Acinetobacter indicus-like strains from cattle including genomic and phylogenetic analyses, antimicrobial susceptibility testing and evaluation of pathogenicity in vitro and in vivo. Nasal and rectal swabs (n = 45) from cattle in Germany were screened for carbapenem-non-susceptible Acinetobacter spp. Thereby, two carbapenem resistant Acinetobacter spp. from the nasal cavities of two calves could be isolated. MALDI-TOF mass spectrometry and 16S rDNA sequencing identified these isolates as A. indicus-like. A phylogenetic tree based on partial rpoB sequences indicated closest relation of the two bovine isolates to the A. indicus type strain A648T and human clinical A. indicus isolates, while whole genome comparison revealed considerable intraspecies diversity. High mimimum inhibitory concentrations were observed for carbapenems and other antibiotics including fluoroquinolones and gentamicin. Whole genome sequencing and PCR mapping revealed that both isolates harboured blaOXA-23 localized on the chromosome and surrounded by interrupted Tn2008 transposon structures. Since the pathogenic potential of A. indicus is unknown, pathogenicity was assessed employing the Galleria (G.) mellonella infection model and an in vitro cytotoxicity assay using A549 human lung epithelial cells. Pathogenicity in vivo (G. mellonella killing assay) and in vitro (cytotoxicity assay) of the two A. indicus-like isolates was lower compared to A. baumannii ATCC 17978 and similar to A. lwoffii ATCC 15309. The reduced pathogenicity of A. indicus compared to A. baumannii correlated with the absence of important virulence genes encoding like phospholipase C1+C2, acinetobactin outer membrane protein BauA, RND-type efflux system proteins AdeRS and AdeAB or the trimeric autotransporter adhesin Ata. The emergence of carbapenem-resistant A. indicus-like strains from cattle carrying blaOXA-23 on transposable elements and revealing genetic

  1. Carbapenem-resistance and pathogenicity of bovine Acinetobacter indicus-like isolates.

    PubMed

    Klotz, Peter; Göttig, Stephan; Leidner, Ursula; Semmler, Torsten; Scheufen, Sandra; Ewers, Christa

    2017-01-01

    The objective of this study was to characterize blaOXA-23 harbouring Acinetobacter indicus-like strains from cattle including genomic and phylogenetic analyses, antimicrobial susceptibility testing and evaluation of pathogenicity in vitro and in vivo. Nasal and rectal swabs (n = 45) from cattle in Germany were screened for carbapenem-non-susceptible Acinetobacter spp. Thereby, two carbapenem resistant Acinetobacter spp. from the nasal cavities of two calves could be isolated. MALDI-TOF mass spectrometry and 16S rDNA sequencing identified these isolates as A. indicus-like. A phylogenetic tree based on partial rpoB sequences indicated closest relation of the two bovine isolates to the A. indicus type strain A648T and human clinical A. indicus isolates, while whole genome comparison revealed considerable intraspecies diversity. High mimimum inhibitory concentrations were observed for carbapenems and other antibiotics including fluoroquinolones and gentamicin. Whole genome sequencing and PCR mapping revealed that both isolates harboured blaOXA-23 localized on the chromosome and surrounded by interrupted Tn2008 transposon structures. Since the pathogenic potential of A. indicus is unknown, pathogenicity was assessed employing the Galleria (G.) mellonella infection model and an in vitro cytotoxicity assay using A549 human lung epithelial cells. Pathogenicity in vivo (G. mellonella killing assay) and in vitro (cytotoxicity assay) of the two A. indicus-like isolates was lower compared to A. baumannii ATCC 17978 and similar to A. lwoffii ATCC 15309. The reduced pathogenicity of A. indicus compared to A. baumannii correlated with the absence of important virulence genes encoding like phospholipase C1+C2, acinetobactin outer membrane protein BauA, RND-type efflux system proteins AdeRS and AdeAB or the trimeric autotransporter adhesin Ata. The emergence of carbapenem-resistant A. indicus-like strains from cattle carrying blaOXA-23 on transposable elements and revealing genetic

  2. Acinetobacter pragensis sp. nov., found in soil and water ecosystems.

    PubMed

    Radolfova-Krizova, Lenka; Maixnerova, Martina; Nemec, Alexandr

    2016-10-01

    This study aimed to define the taxonomic status of a novel, phenetically distinct group of seven strains belonging to the genus Acinetobacter, which were isolated from environmental soil and water samples collected in Central Bohemia, Czech Republic. Comparative sequence analyses of the 16S rRNA, gyrB and rpoB genes showed that all these strains formed respective tight clusters (intracluster sequence similarities of ≥99.8, ≥98.1 and ≥98.3 %, respectively), which were distant from all known Acinetobacter species (≤98.2, ≤84.0 and ≤88.9 %, respectively). The average nucleotide identity and digital DNA-DNA hybridization values (≤83.5 and ≤27.4 %, respectively) between the whole-genome sequence of a group representative (strain ANC 4149T) and those of known taxa were far below the thresholds used to discriminate between bacterial species. The seven strains also formed a tight and distinct cluster based on the genus-wide comparison of whole-cell mass fingerprints generated by matrix-assisted laser desorption/ionization time-of-flight MS and could be distinguished from all other members of the genus Acinetobacter by the combination of their ability to assimilate glutarate and l-tartrate and inability to grow at 37 °C and on l-aspartate. It is concluded that the seven strains represent a novel species for which the name Acinetobacter pragensis sp. nov. is proposed. The type strain is ANC 4149T (=CCM 8637T=CCUG 67962T=CNCTC 7530T).

  3. Draft Genome Sequences of Acinetobacter baumannii Isolates from Wounded Military Personnel.

    PubMed

    Arivett, Brock A; Ream, Dave C; Fiester, Steven E; Kidane, Destaalem; Actis, Luis A

    2016-08-25

    Acinetobacter baumannii is a Gram-negative bacterium capable of causing hospital-acquired infections that has been grouped with Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species as ESKAPE pathogens because of their extensive drug resistance phenotypes and increasing risk to human health. Twenty-four multidrug-resistant A. baumannii strains isolated from wounded military personnel were sequenced and annotated.

  4. Morphine, but not trauma, sensitizes to systemic Acinetobacter baumannii infection.

    PubMed

    Breslow, Jessica M; Monroy, M Alexandra; Daly, John M; Meissler, Joseph J; Gaughan, John; Adler, Martin W; Eisenstein, Toby K

    2011-12-01

    Acinetobacter baumannii is an important nosocomial pathogen in civilian intensive care units. Recently the incidence has increased in wounded military personnel. Morphine is documented in numerous animal studies to be immunosuppressive and to sensitize to infection. The hypotheses were tested that morphine, administered for analgesia in the battlefield, predisposes to Acinetobacter infection, and that the opioid may have an additive or synergistic effect with trauma. To test these hypotheses, an intraperitoneal infection model was established in mice using several Acinetobacter strains. Morphine administered for 48 h by implantation of a slow-release morphine pellet increased mortality compared to animals receiving a placebo pellet, an effect that was blocked by the mu-opioid receptor antagonist, naltrexone. Acinetobacter burdens in the blood, spleens, livers, and lungs of morphine-treated mice, were significantly higher than those in placebo-treated animals, confirming that mortality was due to potentiated growth of the bacteria. There were also elevated levels of pro-inflammatory cytokines in morphine-treated versus placebo-treated mice. Morphine caused a reduction in the total number of cells in the peritoneal cavity, a decrease in the percentage and total numbers of neutrophils, and a decrease in the total number of macrophages. Morphine treatment also suppressed levels of the neutrophil-inducing molecules, IL-17A and KC/CXCL1. However, IL-17A(-/-) mice given morphine were not sensitized to Acintobacter infection to a greater degree than similarly treated wild-type mice. Trauma alone did not sensitize to Acinetobacter infection, and there was no additive effect between morphine and trauma. These results support the hypothesis that morphine potentiates Acinetobacter infection.

  5. Clinical and antimicrobial profile of Acinetobacter spp.: An emerging nosocomial superbug

    PubMed Central

    Tripathi, Purti C.; Gajbhiye, Sunita R.; Agrawal, Gopal Nandlal

    2014-01-01

    Background: Recently, Acinetobacter has emerged as significant hospital pathogen, notoriously known to acquire antibiotic resistance to most of the commonly prescribed antimicrobials. Many risk factors are associated with Acinetobacter infections, especially in patients in intensive care unit (ICU). This study aims to isolate Acinetobacter from various clinical specimens and to determine its antimicrobial sensitivity pattern. Materials and Methods: Identification, speciation and antimicrobial sensitivity testing were performed using the standard microbiological techniques. Slime production was also tested by microtiter plate and tube method. Results: From the processed clinical specimens, 107 Acinetobacter strains (1.02%) were isolated of which 76 (0.74%) isolates were from general wards and 31 (11.96%) were from ICU. Significantly higher percentage of Acinetobacter strains was found in ICU compared with general wards (P < 0.05). Most common Acinetobacter infection was abscess. Infections were more common in males and were associated with major risk factors such as post-surgical, diabetes mellitus, catheterization, extended hospital stay and prolonged antibiotic usage. Acinetobacter baumanii was the most common species isolated to cause abscess, wound infection, etc. 62.61% and 28.97% isolates produced slime by microtiter plate and tube method. Imipenem was most sensitive drug followed by amikacin. Ceftazidime, cefotaxime, piperacillin were most resistant. 43.00% isolates were IPM resistant. A. baumanii was more resistant to commonly used antimicrobials. Conclusion: Acinetobacter nosocomial infections resistant to most antimicrobials have emerged, especially in ICU. Early identification and continued surveillance of prevalent organism will help prevent the spread of Acinetobacter in hospital environment. PMID:24600597

  6. Sequencing of the rpoB gene and flanking spacers for molecular identification of Acinetobacter species.

    PubMed

    La Scola, Bernard; Gundi, Vijay A K B; Khamis, Atieh; Raoult, Didier

    2006-03-01

    Acinetobacter species are defined on the basis of several phenotypic characters, results of DNA-DNA homology, and more recently, similarities or dissimilarities in 16S rRNA gene sequences. However, the 16S rRNA gene is not polymorphic enough to clearly distinguish all Acinetobacter species. We used an RNA polymerase beta-subunit gene (rpoB)-based identification scheme for the delineation of species within the genus Acinetobacter, and towards that end, we determined the complete rpoB gene and flanking spacer (rplL-rpoB and rpoB-rpoC) sequences of the 17 reference strains of Acinetobacter species and 7 unnamed genomospecies. By using complete gene sequences (4,089 bp), we clearly separated all species and grouped them into different clusters. A phylogenetic tree constructed using these sequences was supported by bootstrap values higher than those obtained with 16S rRNA or the gyrB or recA gene. Four pairs of primers enabled us to amplify and sequence two highly polymorphic partial sequences (350 and 450 bp) of the rpoB gene. These and flanking spacers were designed and tested for rapid identification of the 17 reference strains of Acinetobacter species and 7 unnamed genomospecies. Each of these four variable sequences enabled us to delineate most species. Sequences of at least two polymorphic sequences should be used to distinguish Acinetobacter grimontii, Acinetobacter junii, Acinetobacter baylyi, and genomic species 9 from one another. Finally, 21 clinical isolates of Acinetobacter baumannii were tested for intraspecies relationships and assigned correctly to the same species by comparing the partial sequences of the rpoB gene and its flanking spacers.

  7. Comparative genomic analysis of novel Acinetobacter symbionts: A combined systems biology and genomics approach

    PubMed Central

    Gupta, Vipin; Haider, Shazia; Sood, Utkarsh; Gilbert, Jack A.; Ramjee, Meenakshi; Forbes, Ken; Singh, Yogendra; Lopes, Bruno S.; Lal, Rup

    2016-01-01

    The increasing trend of antibiotic resistance in Acinetobacter drastically limits the range of therapeutic agents required to treat multidrug resistant (MDR) infections. This study focused on analysis of novel Acinetobacter strains using a genomics and systems biology approach. Here we used a network theory method for pathogenic and non-pathogenic Acinetobacter spp. to identify the key regulatory proteins (hubs) in each strain. We identified nine key regulatory proteins, guaA, guaB, rpsB, rpsI, rpsL, rpsE, rpsC, rplM and trmD, which have functional roles as hubs in a hierarchical scale-free fractal protein-protein interaction network. Two key hubs (guaA and guaB) were important for insect-associated strains, and comparative analysis identified guaA as more important than guaB due to its role in effective module regulation. rpsI played a significant role in all the novel strains, while rplM was unique to sheep-associated strains. rpsM, rpsB and rpsI were involved in the regulation of overall network topology across all Acinetobacter strains analyzed in this study. Future analysis will investigate whether these hubs are useful as drug targets for treating Acinetobacter infections. PMID:27378055

  8. Acinetobacter baumannii: Evolution of Antimicrobial Resistance—Treatment Options

    PubMed Central

    Doi, Yohei; Murray, Gerald L.; Peleg, Anton Y.

    2015-01-01

    The first decade of the 20th century witnessed a surge in the incidence of infections due to several highly antimicrobial-resistant bacteria in hospitals worldwide. Acinetobacter baumannii is one such organism that turned from an occasional respiratory pathogen into a major nosocomial pathogen. An increasing number of A. baumannii genome sequences have broadened our understanding of the genetic makeup of these bacteria and highlighted the extent of horizontal transfer of DNA. Animal models of disease combined with bacterial mutagenesis have provided some valuable insights into mechanisms of A. baumannii pathogenesis. Bacterial factors known to be important for disease include outer membrane porins, surface structures including capsule and lipopolysaccharide, enzymes such as phospholipase D, iron acquisition systems, and regulatory proteins. A. baumannii has a propensity to accumulate resistance to various groups of antimicrobial agents. In particular, carbapenem resistance has become commonplace, accounting for the majority of A. baumannii strains in many hospitals today. Carbapenem-resistant strains are often resistant to all other routinely tested agents. Treatment of carbapenem-resistant A. baumannii infection therefore involves the use of combinations of last resort agents such as colistin and tigecycline, but the efficacy and safety of these approaches are yet to be defined. Antimicrobial-resistant A. baumannii has high potential to spread among ill patients in intensive care units. Early recognition and timely implementation of appropriate infection control measures is crucial in preventing outbreaks. PMID:25643273

  9. Variants of the gentamicin and tobramycin resistance plasmid pRAY are widely distributed in Acinetobacter.

    PubMed

    Hamidian, Mohammad; Nigro, Steven J; Hall, Ruth M

    2012-12-01

    To determine the cause of resistance to the aminoglycosides gentamicin and tobramycin in Acinetobacter isolates and the location of the resistance genes. Australian Acinetobacter baumannii isolates were screened for resistance to aminoglycosides. PCR followed by restriction digestion of amplicons was used to detect genes and plasmids. Plasmids were isolated and examined by restriction digestion. Plasmid DNA sequences were determined and bioinformatic analysis was used to identify features. The sequence of the bla(OXA-Ab) gene and multilocus sequence typing were used to determine strain types. Isolates that exhibited resistance to gentamicin, kanamycin and tobramycin were of diverse strain types. These isolates all carried the aadB gene cassette, and in all but one the cassette was in a 6 kb plasmid similar to pRAY. The three plasmid sequences determined revealed multiple frame-shift differences in the available pRAY sequence that altered the reading frames. In pRAY*, mobA and mobC mobilization genes were identified, but no potential replication initiation protein was found. pRAY*-v1 differed from pRAY* by 66 single-base differences, and pRAY*-v2 included two insertion sequences, ISAba22, located upstream of the aadB gene cassette, and IS18-like, within ISAba22. The plasmid pRAY* and variants are widely distributed in Acinetobacter spp. and are the most common cause of resistance to gentamicin and tobramycin. Mobilization genes should assist in the dissemination of pRAY* and its variants.

  10. Lettuce and fruits as a source of multidrug resistant Acinetobacter spp.

    PubMed

    Carvalheira, Ana; Silva, Joana; Teixeira, Paula

    2017-06-01

    The role of ready-to-eat products as a reservoir of pathogenic species of Acinetobacter remains unclear. The objective of the present study was to evaluate the presence of Acinetobacter species in lettuces and fruits marketed in Portugal, and their susceptibility to antimicrobials. Acinetobacter spp. were isolated from 77.9% of the samples and these microorganisms were also found as endophytes (i.e. present within the plant tissue) in 12 of 20 samples of lettuces analysed. Among 253 isolates that were identified as belonging to this genus, 181 presented different PFGE profiles, representing different strains. Based on the analysis of the partial sequence of rpoB, 175 strains were identified as members of eighteen distinct species and the remaining six strains may represent five new candidate species since their rpoB sequence similarities with type strains were less than 95%. Acinetobacter calcoaceticus and Acinetobacter johnsonii were the most common species, both with the frequency of 26.5%; and 11% of the strains belong to the Acinetobacter baumannii group (i.e. A. baumannii, Acinetobacter pittii, Acinetobacter seifertii and Acinetobacter nosocomialis), which is most frequently associated with nosocomial infections. Overall, the strains were least susceptible to piperacillin (80.1%), piperacillin-tazobactam (64.1%), ceftazidime (43.1%), ciprofloxacin (16.6%), trimethoprim-sulfamethoxazole (14.9%), imipenem (14.4%) and colistin (13.3%). The most active antimicrobials were minocycline and tetracycline, with 0.6% and 3.9% of strains resistant, respectively. About 29.8% of the strains were classified as multidrug-resistant (MDR), 4.4% as extensively drug-resistant (XDR) and the prevalence of MDR strains within the A. baumannii group (25%) was similar to other species (30.4%). The presence of clinically important species as well as MDR strains in lettuces and fruits may be a threat to public health considering that they may transmit these pathogens to environments

  11. RCH51, a multiply antibiotic-resistant Acinetobacter baumannii ST103IP isolate, carries resistance genes in three plasmids, including a novel potentially conjugative plasmid carrying oxa235 in transposon Tn6252.

    PubMed

    Hamidian, Mohammad; Nigro, Steven J; Hartstein, Rebecca M; Hall, Ruth M

    2017-07-01

    To determine the identity and context of genes conferring antibiotic resistance in a sporadic multiply antibiotic-resistant Acinetobacter baumannii recovered at Royal Children's Hospital, Brisbane. The antibiotic resistance phenotype for 23 antibiotics was determined using disc diffusion or MIC determination. The whole-genome sequence of RCH51 was determined using the Illumina HiSeq platform. Antibiotic resistance determinants were identified using ResFinder. Plasmids were recovered by transformation. Isolate RCH51 belongs to the uncommon STs ST103 IP (7-3-2-1-7-1-4) and ST514 OX (1-52-29-28-18-114-7). It was found to be resistant to sulfamethoxazole, tetracycline, gentamicin, tobramycin and kanamycin and also exhibited reduced susceptibility to imipenem (MIC 2 mg/L) and meropenem (MIC 6 mg/L). RCH51 carries the oxa235 , sul2 , floR , aadB and tet39 resistance genes, all located on plasmids. The largest of the three plasmids, pRCH51-3, is 52 789 bp and carries oxa235 in the ISAba1-bounded transposon Tn 6252 , as well as sul2 and floR . pRCH51-3 represents a new A. baumannii plasmid family that is potentially conjugative as it contains several genes predicted to encode transfer functions. However, conjugation of pRCH51-3 was not detected. The aadB and tet39 resistance genes were each found in small plasmids identical to the known plasmids pRAY*-v1 and pRCH52-1, respectively. The resistance gene complement of RCH51 was found in three plasmids. pRCH51-3, which carries the oxa235 , sul2 and floR resistance genes, represents a new, potentially conjugative A. baumannii plasmid type.

  12. Successful Eradication of Multidrug Resistant Acinetobacter in the Helsinki Burn Centre.

    PubMed

    Lindford, Andrew; Kiuru, Valtteri; Anttila, Veli-Jukka; Vuola, Jyrki

    2015-01-01

    Multidrug-resistant (MDR) Acinetobacter is an important pathogen implicated in nosocomial infections in healthcare environments. Virulence factors, resistance mechanisms, and limited therapeutic options make this pathogen a major problem currently facing burn intensive care units (ICUs) worldwide. The purpose of this study was to assess the effect of infection control measures taken in Helsinki Burn Centre in 2001 on MDR Acinetobacter prevalence in ICU burn patients. Data were retrospectively collected from patient files from 1998 to 2012. ICU burn patients were defined as those with either over 30% of total body surface area burnt or requiring mechanical ventilation. Inclusion criteria consisted of patients who tested positive for Acinetobacter sp. in routine bacterial cultures or cultures taken because of a clinically suspected infection. Infection control interventions performed in 2001 consisted of various shower room renovations and changes in hospital hygiene and burn treatment regimes. Between 1998 and 2012, 75 patients were diagnosed with Acinetobacter sp. colonization. Following the infection control interventions the incidence of Acinetobacter sp. radically declined. Between 1998 and 2001, there were 31 cases of MDR Acinetobacter colonizations diagnosed, but from 2002 to 2012 no MDR strains were found. Changes to hospital hygiene and wound treatment protocols as well as structural changes to the hospital environment can have a major impact on preventing and treating Acinetobacter outbreaks in burn centers.

  13. Multidrug-resistant Acinetobacter meningitis in children

    PubMed Central

    Shah, Ira; Kapdi, Muznah

    2016-01-01

    Acinetobacter species have emerged as one of the most troublesome pathogens for healthcare institutions globally. In more recent times, nosocomial infections involving the central nervous system, skin and soft tissue, and bone have emerged as highly problematic. Acinetobacter species infection is common in intensive care units; however, Acinetobacter baumannii meningitis is rarely reported. Here, we report two cases of Acinetobacter baumannii meningitis which was multidrug resistance and ultimately required the carbapenem group of drugs for the treatment.

  14. Description of Acinetobacter populi sp. nov. isolated from symptomatic bark of Populus x euramericana canker.

    PubMed

    Li, Yong; Chang, Jupu; Guo, Li-min; Wang, Hai-Ming; Xie, Shou-jiang; Piao, Chun-gen; He, Wei

    2015-12-01

    Five Gram-negative, non-motile, rod-shaped bacterial strains were isolated from cankers of Populus x euramericana collected from different locations in Puyang city, Henan Province, China. The five strains were characterized by nutritional and physiological testing and DNA sequence analysis. Haemolysis was not observed on agar media supplemented with sheep erythrocytes. The strains could be distinguished from members of most species of the genus Acinetobacter by their inability to assimilate L-arginine and benzoate. The five strains formed a single branch in phylogenetic trees based on 16S rRNA, gyrB and rpoB individual gene sequence analysis,indicating that they all belonged to a single taxon within the genus Acinetobacter. DNA-DNA hybridization results indicated that the five isolates represented to a single species that was separate from Acinetobacter puyangensis. On the basis of the phenotypic, genotypic and phylogenetic characteristics, the five strains are considered to represent a novel species of the genus Acinetobacter, for which the name Acinetobacter populi sp. nov. is proposed. The typestrain of A. populi sp. nov. is PBJ7T (CFCC 11170T=KCTC 42272T).

  15. Species identification within Acinetobacter calcoaceticus-baumannii complex using MALDI-TOF MS.

    PubMed

    Toh, Benjamin E W; Paterson, David L; Kamolvit, Witchuda; Zowawi, Hosam; Kvaskoff, David; Sidjabat, Hanna; Wailan, Alexander; Peleg, Anton Y; Huber, Charlotte A

    2015-11-01

    Acinetobacter baumannii, one of the more clinically relevant species in the Acinetobacter genus is well known to be multi-drug resistant and associated with bacteremia, urinary tract infection, pneumonia, wound infection and meningitis. However, it cannot be differentiated from closely related species such as Acinetobacter calcoaceticus, Acinetobacter pittii and Acinetobacter nosocomialis by most phenotypic tests and can only be differentiated by specific, time consuming genotypic tests with very limited use in clinical microbiological laboratories. As a result, these species are grouped into the A. calcoaceticus-A. baumannii (Acb) complex. Herein we investigated the mass spectra of 73 Acinetobacter spp., representing ten different species, using an AB SCIEX 5800 MALDI-TOF MS to differentiate members of the Acinetobacter genus, including the species of the Acb complex. RpoB gene sequencing, 16S rRNA sequencing, and gyrB multiplex PCR were also evaluated as orthogonal methods to identify the organisms used in this study. We found that whilst 16S rRNA and rpoB gene sequencing could not differentiate A. pittii or A. calcoaceticus, they can be differentiated using gyrB multiplex PCR and MALDI-TOF MS. All ten Acinetobacter species investigated could be differentiated by their MALDI-TOF mass spectra. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Genomic and phenotypic characterization of the species Acinetobacter venetianus.

    PubMed

    Fondi, Marco; Maida, Isabel; Perrin, Elena; Orlandini, Valerio; La Torre, Laura; Bosi, Emanuele; Negroni, Andrea; Zanaroli, Giulio; Fava, Fabio; Decorosi, Francesca; Giovannetti, Luciana; Viti, Carlo; Vaneechoutte, Mario; Dijkshoorn, Lenie; Fani, Renato

    2016-02-23

    Crude oil is a complex mixture of hydrocarbons and other organic compounds that can produce serious environmental problems and whose removal is highly demanding in terms of human and technological resources. The potential use of microbes as bioremediation agents is one of the most promising fields in this area. Members of the species Acinetobacter venetianus have been previously characterized for their capability to degrade n-alkanes and thus may represent interesting model systems to implement this process. Although a preliminary experimental characterization of the overall hydrocarbon degradation capability has been performed for five of them, to date, the genetic/genomic features underlying such molecular processes have not been identified. Here we have integrated genomic and phenotypic information for six A. venetianus strains, i.e. VE-C3, RAG-1(T), LUH 13518, LUH 7437, LUH 5627 and LUH 8758. Besides providing a thorough description of the A. venetianus species, these data were exploited to infer the genetic features (presence/absence patterns of genes) and the short-term evolutionary events possibly responsible for the variability in n-alkane degradation efficiency of these strains, including the mechanisms of interaction with the fuel droplet and the subsequent catabolism of this pollutant.

  17. Genomic and phenotypic characterization of the species Acinetobacter venetianus

    PubMed Central

    Fondi, Marco; Maida, Isabel; Perrin, Elena; Orlandini, Valerio; La Torre, Laura; Bosi, Emanuele; Negroni, Andrea; Zanaroli, Giulio; Fava, Fabio; Decorosi, Francesca; Giovannetti, Luciana; Viti, Carlo; Vaneechoutte, Mario; Dijkshoorn, Lenie; Fani, Renato

    2016-01-01

    Crude oil is a complex mixture of hydrocarbons and other organic compounds that can produce serious environmental problems and whose removal is highly demanding in terms of human and technological resources. The potential use of microbes as bioremediation agents is one of the most promising fields in this area. Members of the species Acinetobacter venetianus have been previously characterized for their capability to degrade n-alkanes and thus may represent interesting model systems to implement this process. Although a preliminary experimental characterization of the overall hydrocarbon degradation capability has been performed for five of them, to date, the genetic/genomic features underlying such molecular processes have not been identified. Here we have integrated genomic and phenotypic information for six A. venetianus strains, i.e. VE-C3, RAG-1T, LUH 13518, LUH 7437, LUH 5627 and LUH 8758. Besides providing a thorough description of the A. venetianus species, these data were exploited to infer the genetic features (presence/absence patterns of genes) and the short-term evolutionary events possibly responsible for the variability in n-alkane degradation efficiency of these strains, including the mechanisms of interaction with the fuel droplet and the subsequent catabolism of this pollutant. PMID:26902269

  18. The underappreciated in vitro activity of tedizolid against Bacteroides fragilis species, including strains resistant to metronidazole and carbapenems.

    PubMed

    Goldstein, Ellie J C; Citron, Diane M; Tyrrell, Kerin L; Leoncio, Elisa S; Merriam, C Vreni

    2017-02-01

    Because Bacteroides fragilis has the ability to develop mechanisms of resistance to almost all antibiotics, we studied the comparative in vitro activity of tedizolid against 124 Bacteroides group species clinical isolates, including carbapenem, metronidazole and piperacillin-tazobactam resistant strains. Tedizolid had an MIC90 of 2 μg/ml (range, 0.5-4 μg/ml) and was 1-4 times more active than linezolid that had an MIC90 of 8 μg/ml (range, 2-16 μg/ml). It was also active (MICs 0.5-2 μg/ml) against the 27 ertapenem, 2 metronidazole and 12 piperacillin-tazobactam resistant strains tested. This suggests that tedizolid may be useful treating infections, including bacteremias, due to resistant B. fragilis group species, as well as, mixed skin and soft tissue infections such as diabetic foot infections caused by Gram-positive aerobes and B. fragilis group species. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Use of Comparative Genomics To Characterize the Diversity of Acinetobacter baumannii Surveillance Isolates in a Health Care Institution.

    PubMed

    Wallace, Lalena; Daugherty, Sean C; Nagaraj, Sushma; Johnson, J Kristie; Harris, Anthony D; Rasko, David A

    2016-10-01

    Despite the increasing prevalence of the nosocomial pathogen Acinetobacter baumannii, little is known about which genomic components contribute to clinical presentation of this important pathogen. Most whole-genome comparisons of A. baumannii have focused on specific genomic regions associated with phenotypes in a limited number of genomes. In this work, we describe the results of a whole-genome comparative analysis of 254 surveillance isolates of Acinetobacter species, 203 of which were A. baumannii, isolated from perianal swabs and sputum samples collected as part of an infection control active surveillance program at the University of Maryland Medical Center. The collection of surveillance isolates includes both carbapenem-susceptible and -resistant isolates. Based on the whole-genome phylogeny, the A. baumannii isolates collected belong to two major phylogenomic lineages. Results from multilocus sequence typing indicated that one of the major phylogenetic groups of A. baumannii was comprised solely of strains from the international clonal lineage 2. The genomic content of the A. baumannii isolates was examined using large-scale BLAST score ratio analysis to identify genes that are associated with carbapenem-susceptible and -resistant isolates, as well as genes potentially associated with the source of isolation. This analysis revealed a number of genes that were exclusive or at greater frequency in each of these classifications. This study is the most comprehensive genomic comparison of Acinetobacter isolates from a surveillance study to date and provides important information that will contribute to our understanding of the success of A. baumannii as a human pathogen.

  20. Acinetobacter sp. isolates from emergency departments in two hospitals of South Korea.

    PubMed

    Choi, Ji-Young; Ko, Eun Ah; Kwon, Ki Tae; Lee, Shinwon; Kang, Choel In; Chung, Doo-Ryeon; Peck, Kyong Ran; Song, Jae-Hoon; Ko, Kwan Soo

    2014-10-01

    A total of 114 Acinetobacter sp. isolates were collected from patients in the emergency departments (EDs) of two Korean hospitals. Most isolates belonged to the Acinetobacter baumannii complex (105 isolates, 92.1 %). Imipenem resistance was found in 39 isolates (34.2 %) of the Acinetobacter sp. isolates, and 6 colistin-resistant isolates were also identified. Species distribution and antimicrobial-resistance rates were different between the two hospitals. In addition, two main clones were identified in the imipenem-resistant A. baumannii isolates from hospital B, but very diverse and novel genotypes were found in those from hospital A. Many Acinetobacter sp. isolates, including the imipenem-resistant A. baumannii, are considered to be associated with the community. The evidence of high antimicrobial resistance and different features in these Acinetobacter sp. isolates between the two EDs suggests the need for continuous testing to monitor changes in epidemiology.

  1. Evaluation of thioesterases from Acinetobacter baylyi for production of free fatty acids.

    PubMed

    Ukey, Rahul; Holmes, William E; Bajpai, Rakesh; Chistoserdov, Andrei Y

    2017-04-01

    Acinetobacter baylyi is one of few Gram-negative bacteria capable of accumulating storage lipids in the form of triacylglycerides and wax esters, which makes it an attractive candidate for production of lipophilic products, including biofuel precursors. Thioesterases play a significant dual role in the triacylglyceride and wax ester biosynthesis by either providing or removing acyl-CoA from this pathway. Therefore, 4 different thioesterase genes were cloned from Acinetobacter baylyi ADP1 and expressed in Escherichia coli to investigate their contribution to free fatty acids (FFAs) accumulation. Overexpression of the genes tesA' (a leaderless form of the gene tesA) and tesC resulted in increased accumulation of FFAs when compared with the host E. coli strain. Overexpression of tesA' showed a 1.87-fold increase in production of long-chain fatty acids (C16 to C18) over the host strain. Unlike TesC and the other investigated thioesterases, the TesA' thioesterase also produced shorter chain FFAs (e.g., myristic acid) and unsaturated FFAs (e.g., cis-vaccenic acid (18:1Δ11)). A comparison of the remaining 3 A. baylyi ADP1 thioesterases (encoded by the tesB, tesC, and tesD genes) revealed that only the strain containing the tesC gene produced statistically higher levels of FFAs over the control, suggesting that it possesses the acyl-ACP thioesterase activity. Both E. coli strains containing the tesB and tesD genes produced levels of FFAs similar to those of the plasmid-free control E. coli strain, which indicates that TesB and TesD lack the acyl-ACP thioesterase activity.

  2. Acinetobacter: an underrated foodborne pathogen?

    PubMed

    Amorim, Angelo Maximo Batista de; Nascimento, Janaína Dos Santos

    2017-02-28

    The increasing prevalence of foodborne diseases observed in developing countries has been linked to a rise in the consumption of raw foods. However, unlike the classical pathogens that are commonly implicated in foodborne illnesses, members of the genus Acinetobacter are rarely associated with diarrheal disease, probably because of the difficulty in isolating these Gram-negative bacteria from food sources. Nevertheless, several species of Acinetobacter, especially A. baumannii, possess many of the characteristics associated with successful pathogens and exhibit a prodigious ability to acquire the multiple-drug resistance (MDR) phenotype. In this mini-review, we summarize the epidemiological data relating to MDR Acinetobacter and consider evidence suggesting that contaminated dairy products, along with raw fruit and vegetables, constitute extra-hospital reservoirs of this underrated pathogen, and may represent an increased risk to immunocompromised individuals and young children in healthcare settings.

  3. Antibiotic susceptibility of Acinetobacter species in intensive care unit in Montenegro.

    PubMed

    Mijovic, Gordana; Pejakov, Ljubica; Vujosevic, Danijela

    2016-08-01

    The global increase in multidrug resistance of Acinetobacter has created widespread problems in the treatment of patients in intensive care units (ICUs). The aim of this study was to assess the current level of antimicrobial susceptibility of Acinetobacter species in ICU of Clinical Centre of Montenegro and determine their epidemiology. Antibiotic susceptibility was tested in 70 isolates of Acinetobacter collected from non-repeating samples taken from 40 patients. The first nine isolates were genotyped by repetitive sequence-based PCR (rep-PCR). Tigecycline was found to be the most active antimicrobial agent with 80.6% of susceptibility. All the isolates were multidrug resistant with fully resistance to cefalosporinas, piperacillin and piperacillin/tazobactam. More than half of them (58.5%) were probably extensively resistant. Seven out of nine examined strains were clonally related by rep-PCR. Our results showed extremely high rate of multidrug resistance (MDR) of Acinetobacter isolates and high percentage of its clonally spreading.

  4. An Antimicrobial Metabolite from Bacillus sp.: Significant Activity Against Pathogenic Bacteria Including Multidrug-Resistant Clinical Strains

    PubMed Central

    Chalasani, Ajay G.; Dhanarajan, Gunaseelan; Nema, Sushma; Sen, Ramkrishna; Roy, Utpal

    2015-01-01

    In this study, the cell free modified tryptone soya broth (pH 7.4 ± 0.2) of Bacillus subtilis URID 12.1 showed significant antimicrobial activity against multidrug-resistant strains of Staphylococcus aureus, S. epidermidis, Streptococcus pyogenes and Enterococcus faecalis. The partially purified antimicrobial molecule was found to be resistant to extremes of pH and temperatures and also to higher concentrations of trypsin and proteinase K. The antimicrobial molecule was purified by a three-step method that included reversed-phase high performance liquid chromatography (RP-HPLC). The minimum inhibitory concentration (MIC) values were determined for 14 species of bacteria using a microbroth dilution technique. The HPLC-purified fraction showed the MICs ranging from 0.5 to 16 μg/ml for methicillin and vancomycin-resistant Staphylococcus aureus (MVRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) strains. The molecular mass of the antimicrobial compound was determined to be 842.37 Da. The same antimicrobial fraction showed negligible haemolytic activity against human red blood cells even at a concentration as high as 100 μg/ml. Because of its significant antimicrobial activity at low MIC values coupled with its non-haemolytic property, it may prove to be a novel antimicrobial lead molecule. PMID:26696963

  5. Update on Acinetobacter species: mechanisms of antimicrobial resistance and contemporary in vitro activity of minocycline and other treatment options.

    PubMed

    Castanheira, Mariana; Mendes, Rodrigo E; Jones, Ronald N

    2014-12-01

    Among Acinetobacter species, A. baumannii and other closely related species are commonly implicated in nosocomial infections. These organisms are usually multidrug resistant (MDR), and therapeutic options to treat A. baumannii infections are very limited. Clinicians have been resorting to older antimicrobial agents to treat infections caused by MDR A. baumannii, and some of these agents have documented toxicity and/or are not optimized for the infection type to be treated. Recent clinical experience supported by antimicrobial susceptibility data suggests that minocycline has greater activity than other tetracyclines and glycylcyclines against various MDR pathogens that have limited therapeutic options available, including Acinetobacter species. An intravenous formulation of minocycline has recently become available for clinical use, and in contrast to most older tetracyclines, minocycline has high activity against Acinetobacter species. In this report, we summarized some of the characteristics of the tetracycline class, and quantified the minocycline activity against contemporary (2007-2011) isolates and its potential therapeutic role against a collection of 5477 A. baumannii and other relevant gram-negative organisms when compared directly with tetracycline, doxycycline, and other broad-spectrum antimicrobial agents. Acinetobacter baumannii strains were highly resistant to all agents tested, with the exception of minocycline (79.1% susceptible) and colistin (98.8% susceptible). Minocycline (minimum inhibitory concentration that inhibits 50% and 90% of the isolates [MIC(50/90)]: 1/8 µg/mL) displayed greater activity than doxycycline (MIC(50/90): 2/>8 µg/mL) and tetracycline hydrochloride (HCL) (only 30.2% susceptible) against A. baumannii isolates, and was significantly more active than other tetracyclines against Burkholderia cepacia, Escherichia coli, Serratia marcescens, and Stenotrophomonas maltophilia isolates. In vitro susceptibility testing using

  6. Code blue: Acinetobacter baumannii, a nosocomial pathogen with a role in the oral cavity

    PubMed Central

    Richards, A.M.; Kwaik, Y. Abu; Lamont, R.J.

    2015-01-01

    SUMMARY Actinetobacter baumannii is an important nosocomial pathogen that can cause a wide range of serious conditions including pneumonia, meningitis, necrotizing fasciitis and sepsis. It is also a major cause of wound infections in military personnel injured during the conflicts in Afghanistan and Iraq, leading to its popular nickname of ‘Iraqibacter’. Contributing to its success in clinical settings is resistance to environmental stresses such as desiccation and disinfectants. Moreover, in recent years there has been a dramatic increase in the number of A. baumannii strains with resistance to multiple antibiotic classes. Acinetobacter baumannii is an inhabitant of oral biofilms, which can act as a reservoir for pneumonia and chronic obstructive pulmonary disease. Subgingival colonization by A. baumannii increases the risk of refractory periodontitis. Pathogenesis of the organism involves adherence, biofilm formation and iron acquisition. In addition, A. baumannii can induce apoptotic cell death in epithelial cells and kill hyphal forms of Candida albicans. Virulence factors that have been identified include pili, the outer membrane protein OmpA, phospholipases and extracellular polysaccharide. Acinetobacter baumannii can sense blue light through a blue-light sensing using flavin (BLUF) domain protein, BlsA. The resulting conformational change in BlsA leads to changes in gene expression, including virulence genes. PMID:25052812

  7. Code blue: Acinetobacter baumannii, a nosocomial pathogen with a role in the oral cavity.

    PubMed

    Richards, A M; Abu Kwaik, Y; Lamont, R J

    2015-02-01

    Actinetobacter baumannii is an important nosocomial pathogen that can cause a wide range of serious conditions including pneumonia, meningitis, necrotizing fasciitis and sepsis. It is also a major cause of wound infections in military personnel injured during the conflicts in Afghanistan and Iraq, leading to its popular nickname of 'Iraqibacter'. Contributing to its success in clinical settings is resistance to environmental stresses such as desiccation and disinfectants. Moreover, in recent years there has been a dramatic increase in the number of A. baumannii strains with resistance to multiple antibiotic classes. Acinetobacter baumannii is an inhabitant of oral biofilms, which can act as a reservoir for pneumonia and chronic obstructive pulmonary disease. Subgingival colonization by A. baumannii increases the risk of refractory periodontitis. Pathogenesis of the organism involves adherence, biofilm formation and iron acquisition. In addition, A. baumannii can induce apoptotic cell death in epithelial cells and kill hyphal forms of Candida albicans. Virulence factors that have been identified include pili, the outer membrane protein OmpA, phospholipases and extracellular polysaccharide. Acinetobacter baumannii can sense blue light through a blue-light sensing using flavin (BLUF) domain protein, BlsA. The resulting conformational change in BlsA leads to changes in gene expression, including virulence genes. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Influence of relative humidity and suspending menstrua on survival of Acinetobacter spp. on dry surfaces.

    PubMed Central

    Jawad, A; Heritage, J; Snelling, A M; Gascoyne-Binzi, D M; Hawkey, P M

    1996-01-01

    Acinetobacter spp. are being reported with increasing frequency as a cause of nosocomial infection and have been isolated from the skin of healthy individuals, patients, hospital staff, dry nonbiotic objects, and different pieces of medical equipment. Factors affecting the survival of Acinetobacter spp. under conditions closely similar to those found in the hospital environment were investigated in the present study to help us understand the epidemiology of nosocomial Acinetobacter infection. Bacterial cells were suspended in distilled water or bovine serum albumin and were dried onto glass coverslips and kept at different relative humidities. Cells washed from coverslips were used to determined viable counts. Freshly isolated strains of Acinetobacter spp. belonging to the clinically important Acinetobacter calcoaceticus-Acinetobacter baumannii complex were found to be more resistant to drying conditions (e.g., 30 days for A. baumannii 16/49) than American Type Culture Collection strains (e.g., 2 days for A. baumannii ATCC 9955). The majority of strains belonging to the Acb complex had survival times similar to those observed for the gram-positive organism Staphylococcus aureus tested in the experiment. Survival times were prolonged for almost all the strains tested when they were suspended in bovine serum albumin (e.g., 60 days for A. baumannii R 447) compared with those for strains suspended in distilled water (11 days for R 447). The survival times for strains at higher relative humidity (31 or 93%) were longer than those for strains of Acinetobacter kept at a relative humidity of 10% (11 days at 31% relative humidity and 4 days at 10% relative humidity for R447). These findings are consistent with the observed tendency of Acinetobacter spp. to survive on dry surfaces, and they can be transferred not only by moist vectors but also under dry conditions in a hospital environment during nosocomial infection outbreaks. The results obtained in the experiment support

  9. Quantification of Siderophore and Hemolysin from Stachybotrys chartarum Strains, Including a Strain Isolated from the Lung of a Child with Pulmonary Hemorrhage and Hemosiderosis

    PubMed Central

    Vesper, Stephen J.; Dearborn, Dorr G.; Elidemir, Okan; Haugland, Richard A.

    2000-01-01

    A strain of Stachybotrys chartarum was recently isolated from the lung of a pulmonary hemorrhage and hemosiderosis (PH) patient in Texas (designated the Houston strain). This is the first time that S. chartarum has been isolated from the lung of a PH patient. In this study, the Houston strain and 10 strains of S. chartarum isolated from case (n = 5) or control (n = 5) homes in Cleveland were analyzed for hemolytic activity, siderophore production, and relatedness as measured by random amplified polymorphic DNA analysis. PMID:10831457

  10. Proliferation of spacecraft-associated Acinetobacter on alcohol solvents

    NASA Astrophysics Data System (ADS)

    Mogul, Rakesh; Cepeda, Ivonne; Brasali, Hania; Gornick, Trevor; Jain, Chirag; Kim, Eun Jin; Nguyen, Vinh Bao; Oei, Alex; Rodriguez, Joseph; Walker, Jillian; Savla, Gautam

    The Acinetobacter are the most abundant Gram-negative and non-spore forming bacteria found in the cleanroom facilities for Mars spacecraft. The spacecraft-associated Acinetobacter are extremotolerant towards hydrogen peroxide and have been shown to increase in abundance as a result of the spacecraft assembly process. To better understand the oligotrophic growth in the cleanroom environments, we have measured the growth of several Acinetobacter strains against ethanol and isopropanol, which are cleaning solvents used in the spacecraft assembly process. Our studies show that A. radioresistens 50v1, which was isolated from Mars Odyssey orbiter, optimally proliferates on 300 mM ethanol under minimal conditions at a growth rate that is 2-fold higher than that of the A. radioresistens type strain (strain 43998 (T) ). The impact of transition metals on the growth rates followed the trend of Fe (2+) > Mn (2+) > Zn (2+) , where Zn (2+) was inhibitory. In contrast, no growth on ethanol was observed for the novel species A. phoenicis 2P01AA, which was isolated from the facilities for the Mars Phoenix lander. Alcohol dehydrogenase activities measured in rich and minimal media paralleled these observations with the 50v1 strain possessing higher specific activities than the type strain, and the 2P01AA strain displaying no measurable activity in rich media. Preliminary studies indicate that isopropanol is insufficient as an energy source when in culture. The significance of these results as well as the observed differences between the Odyssey and Phoenix-associated strains will be discussed.

  11. Acinetobacter Peritoneal Dialysis Peritonitis: A Changing Landscape over Time

    PubMed Central

    Chao, Chia-Ter; Lee, Szu-Ying; Yang, Wei-Shun; Chen, Huei-Wen; Fang, Cheng-Chung; Yen, Chung-Jen; Chiang, Chih-Kang; Hung, Kuan-Yu; Huang, Jenq-Wen

    2014-01-01

    Background Acinetobacter species are assuming an increasingly important role in modern medicine, with their persistent presence in health-care settings and antibiotic resistance. However, clinical reports addressing this issue in patients with peritoneal dialysis (PD) peritonitis are rare. Methods All PD peritonitis episodes caused by Acinetobacter that occurred between 1985 and 2012 at a single centre were retrospectively reviewed. Clinical features, microbiological data, and outcomes were analysed, with stratifications based upon temporal periods (before and after 2000). Results Acinetobacter species were responsible for 26 PD peritonitis episodes (3.5% of all episodes) in 25 patients. A. baumannii was the most common pathogen (54%), followed by A. iwoffii (35%), with the former being predominant after 2000. Significantly more episodes resulted from breaks in exchange sterility after 2000, while those from exit site infections decreased (P = 0.01). The interval between the last and current peritonitis episodes lengthened significantly after 2000 (5 vs. 13.6 months; P = 0.05). All the isolates were susceptible to cefepime, fluoroquinolone, and aminoglycosides, with a low ceftazidime resistance rate (16%). Nearly half of the patients (46%) required hospitalisation for their Acinetobacter PD-associated peritonitis, and 27% required an antibiotic switch. The overall outcome was fair, with no mortality and a 12% technique failure rate, without obvious interval differences. Conclusions The temporal change in the microbiology and origin of Acinetobacter PD-associated peritonitis in our cohort suggested an important evolutional trend. Appropriate measures, including technique re-education and sterility maintenance, should be taken to decrease the Acinetobacter peritonitis incidence in PD patients. PMID:25314341

  12. QUANTIFICATION OF SIDEROPHORE AND HEMOLYSIN FROM STACHYBOTRYS CHARTARUM STRAINS, INCLUDING A STRAIN ISOLATED FROM THE LUNG OF A CHILD WITH PULMONARY HEMORRHAGE AND HEMOSIDEROSIS

    EPA Science Inventory

    A strain of Stachybotrys chartarum was recently isolated from the lung of a pulmonary hemorrhage and hemosiderosis (PH) patient in Texas (designated the Houston strain). This is the first time that S. chartarum has been isolated from the lung of a PH patient. In this study, the ...

  13. Osmotic Compounds Enhance Antibiotic Efficacy against Acinetobacter baumannii Biofilm Communities.

    PubMed

    Falghoush, Azeza; Beyenal, Haluk; Besser, Thomas E; Omsland, Anders; Call, Douglas R

    2017-10-01

    Biofilm-associated infections are a clinical challenge, in part because a hydrated matrix protects the bacterial community from antibiotics. Herein, we evaluated how different osmotic compounds (maltodextrin, sucrose, and polyethylene glycol [PEG]) enhance antibiotic efficacy against Acinetobacter baumannii biofilm communities. Established (24-h) test tube biofilms (strain ATCC 17978) were treated with osmotic compounds in the presence or absence of 10× the MIC of different antibiotics (50 μg/ml tobramycin, 20 μg/ml ciprofloxacin, 300 μg/ml chloramphenicol, 30 μg/ml nalidixic acid, or 100 μg/ml erythromycin). Combining antibiotics with hypertonic concentrations of the osmotic compounds for 24 h reduced the number of biofilm bacteria by 5 to 7 log (P < 0.05). Increasing concentrations of osmotic compounds improved the effect, but there was a trade-off with increasing solution viscosity, whereby low-molecular-mass compounds (sucrose, 400-Da PEG) worked better than higher-mass compounds (maltodextrin, 3,350-Da PEG). Ten other A. baumannii strains were similarly treated with 400-Da PEG and tobramycin, resulting in a mean 2.7-log reduction in recoverable bacteria compared with tobramycin treatment alone. Multivariate regression models with data from different osmotic compounds and nine antibiotics demonstrated that the benefit from combining hypertonic treatments with antibiotics is a function of antibiotic mass and lipophilicity (r(2) > 0.82; P < 0.002), and the relationship was generalizable for biofilms formed by A. baumannii and Escherichia coli K-12. Augmenting topical antibiotic therapies with a low-mass hypertonic treatment may enhance the efficacy of antibiotics against wound biofilms, particularly when using low-mass hydrophilic antibiotics.IMPORTANCE Biofilms form a barrier that protects bacteria from environmental insults, including exposure to antibiotics. We demonstrated that multiple osmotic compounds can enhance antibiotic efficacy against

  14. Cell culture isolation and sequence analysis of genetically diverse US porcine epidemic diarrhea virus strains including a novel strain with a large deletion in the spike gene.

    PubMed

    Oka, Tomoichiro; Saif, Linda J; Marthaler, Douglas; Esseili, Malak A; Meulia, Tea; Lin, Chun-Ming; Vlasova, Anastasia N; Jung, Kwonil; Zhang, Yan; Wang, Qiuhong

    2014-10-10

    The highly contagious and deadly porcine epidemic diarrhea virus (PEDV) first appeared in the US in April 2013. Since then the virus has spread rapidly nationwide and to Canada and Mexico causing high mortality among nursing piglets and significant economic losses. Currently there are no efficacious preventive measures or therapeutic tools to control PEDV in the US. The isolation of PEDV in cell culture is the first step toward the development of an attenuated vaccine, to study the biology of PEDV and to develop in vitro PEDV immunoassays, inactivation assays and screen for PEDV antivirals. In this study, nine of 88 US PEDV strains were isolated successfully on Vero cells with supplemental trypsin and subjected to genomic sequence analysis. They differed genetically mainly in the N-terminal S protein region as follows: (1) strains (n=7) similar to the highly virulent US PEDV strains; (2) one similar to the reportedly US S INDEL PEDV strain; and (3) one novel strain most closely related to highly virulent US PEDV strains, but with a large (197aa) deletion in the S protein. Representative strains of these three genetic groups were passaged serially and grew to titers of ∼5-6log10 plaque forming units/mL. To our knowledge, this is the first report of the isolation in cell culture of an S INDEL PEDV strain and a PEDV strain with a large (197aa) deletion in the S protein. We also designed primer sets to detect these genetically diverse US PEDV strains. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Coculture degradation of selected PCB congeners by two Acinetobacter sp

    SciTech Connect

    Adriaens, P.

    1989-01-01

    Polychlorinated biphenyls (PCBs) have been introduced in the environment for nearly six decades and are considered to be refractile to microbial attack, since PCBs have to be degraded via cometabolic processes, which occur in the obligate presence of an alternative growth substrate. However, cometabolism of PCBs has been demonstrated to accumulate chlorobenzoates as the main intermediates. Therefore, the complete mineralization of PCBs can only be obtained by coculturing at least a PCB cometabolizing and a chlorobenzoate utilizing microorganism, or by constructing a recombinant strain harboring the complementary pathways of both strains. Therefore, coculture mineralization of PCBs in suspended culture was obtained by providing biphenyl or 4-chlorobiphenyl as the growth substrate for Acinetobacter sp. strain P6, a PCB cometabolizer, while the chlorobenzoates were used as growth substrates by Acinetobacter sp. strain 4-CB1, which was isolated on 4-chlorobenzoate. 4-Chlorobenzoate (4-CB) was metabolized after hydrolytic dehalogenation to 4-hydroxybenzoate (4-HB) via the protocatechuate pathway. Acinetobacter sp. strain 4-CB1 has the metabolic ability to carry out the degradation of 3,4-DCB. Although this strain does not grow on this compound, it cometabolizes 3,4-DCB to 3-chloro-4-hydroxybenzoate (3-C-4-OHB), which is used as a growth substrate and further metabolized via 4-carboxy-1,2-benzoquinone. This degradation process was termed cryptic cometabolism. 3,4-DCB has shown to be a substrate inhibitor (Ki = 1,840 {mu}M) and an uncompetitive inhibitor for 4-CB metabolism. Additionally, 3-C-4-OHB was a competitive inhibitor (Ki = 12 {mu}M) for the 4-HB monooxygenase, while the quinone uncompetitively inhibited 4-CB metabolism (Ki = 50 {mu}M).

  16. Carbapenem resistance in a human clinical isolate identified to be closely related to Acinetobacter indicus.

    PubMed

    Bonnin, Rémy A; Poirel, Laurent; van der Reijden, Tanny J K; Dijkshoorn, Lenie; Lescat, Mathilde; Nordmann, Patrice

    2014-10-01

    Here we report a case of carbapenem resistance in a human clinical isolate that was found to be closely related to the newly described environmental species Acinetobacter indicus. This strain harboured the blaOXA-23 carbapenemase gene located on a conjugative plasmid. Partial sequencing of 16S rDNA and rpoB genes, together with matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) analysis, showed that this strain was distantly related to the Acinetobacter baumannii-calcoaceticus complex and was closely related to A. indicus.

  17. Detection of Acinetobacter spp. in rural drinking water supplies.

    PubMed

    Bifulco, J M; Shirey, J J; Bissonnette, G K

    1989-09-01

    A bacteriological survey was conducted of untreated, individual groundwater supplies in Preston County, W.Va. Nearly 60% of the water supplies contained total coliforms in excess of the U.S. Environmental Protection Agency maximum contaminant level of 1 CFU/100 ml. Approximately one-third of the water systems contained fecal coliforms and/or fecal streptococci. Acinetobacter spp. were detected in 38% of the groundwater supplies at an arithmetic mean density of 8 CFU/100 ml and were present in 16% of the water supplies in the absence of total coliforms, posing some concern about the usefulness of total coliforms as indicators of the presence of this opportunistic pathogen. Slime production, a virulence factor for A. calcoaceticus, was not significantly different between well water isolates and clinical strains, suggesting some degree of pathogenic potential for strains isolated from groundwater. In addition, several Acinetobacter isolates were able to interfere with sheen production by some coliform bacteria on M-Endo medium, adding further to the possible significance of Acinetobacter spp. in groundwater supplies.

  18. Detection of Acinetobacter spp. in rural drinking water supplies.

    PubMed Central

    Bifulco, J M; Shirey, J J; Bissonnette, G K

    1989-01-01

    A bacteriological survey was conducted of untreated, individual groundwater supplies in Preston County, W.Va. Nearly 60% of the water supplies contained total coliforms in excess of the U.S. Environmental Protection Agency maximum contaminant level of 1 CFU/100 ml. Approximately one-third of the water systems contained fecal coliforms and/or fecal streptococci. Acinetobacter spp. were detected in 38% of the groundwater supplies at an arithmetic mean density of 8 CFU/100 ml and were present in 16% of the water supplies in the absence of total coliforms, posing some concern about the usefulness of total coliforms as indicators of the presence of this opportunistic pathogen. Slime production, a virulence factor for A. calcoaceticus, was not significantly different between well water isolates and clinical strains, suggesting some degree of pathogenic potential for strains isolated from groundwater. In addition, several Acinetobacter isolates were able to interfere with sheen production by some coliform bacteria on M-Endo medium, adding further to the possible significance of Acinetobacter spp. in groundwater supplies. PMID:2529816

  19. Extremotolerant survival and proteomics of Acinetobacter isolated from spacecraft assembly facilities

    NASA Astrophysics Data System (ADS)

    Mogul, Rakesh; Vaishampayan, Parag; Venkateswaran, Kasthuri; McCoy, Kelly; Derecho, Ivy; Dallal, Freida

    2012-07-01

    Herein, we report on the extreme hydrogen peroxide resistance of Acinetobacter isolated from the assembly facilities for the Mars Odyssey orbiter and Phoenix lander. Specific activity experiments on 10 different spacecraft-associated Acinetobacter strains show that the catalase contents are 15-250-fold greater than that of E. coli. Among this group, the highest and lowest catalase-containing strains, which were Acinetobacter nov. sp. 2P01AA and Acinetobacter radioresistens 50v1, demonstrated no significant and 2-log reductions in survivability upon exposure to 100 mM hydrogen peroxide (1 hr), respectively. These survivals are among the highest reported for non-spore forming Gram-negative bacteria. Comparative proteomics on these strains reveals that alkyl hydroperoxide reductase, ATP synthase, dihydrolipoamide dehydrogenase, and peptidyl-tRNA hydrolase also contribute to the hydrogen peroxide extremotolerance. Together, the survival and metabolic features of the spacecraft-associated Acinetobacter indicate that survival in the dry and low-nutrient environments of clean rooms is supported by factors such as oxidant degradation, energy management, and protein biosynthesis.

  20. Acinetobacter baumannii: biology and drug resistance - role of carbapenemases.

    PubMed

    Nowak, Pawel; Paluchowska, Paulina

    2016-01-01

    Acinetobacter baumannii is a Gram-negative, glucose-non-fermenting, oxidase-negative coccobacillus, most commonly associated with the hospital settings. The ability to survive in adverse environmental conditions as well as high level of natural and acquired antimicrobial resistance make A. baumannii one of the most important nosocomial pathogens. While carbapenems have long been considered as antimicrobials of last-resort, the rates of clinical A. baumannii strains resistant to these antibiotics are increasing worldwide. Carbapenem resistance among A. baumannii is conferred by coexisting mechanisms including: decrease in permeability of the outer membrane, efflux pumps, production of beta-lactamases, and modification of penicillin-binding proteins. The most prevalent mechanism of carbapenem resistance among A. baumannii is associated with carbapenem-hydro-lysing enzymes that belong to Ambler class D and B beta-lactamases. In addition, there have also been reports of resistance mediated by selected Ambler class A carbapenemases among A. baumannii strains. Resistance determinants in A. baumannii are located on chromosome and plasmids, while acquisition of new mechanisms can be mediated by insertion sequences, integrons, transposons, and plasmids. Clinical relevance of carbapen-em resistance among strains isolated from infected patients, carriers and hospital environment underlines the need for carbapenemase screening. Currently available methods vary in principle, accuracy and efficiency. The techniques that deserve particular attention belong to both easily accessible unsophisticated methods as well as advanced techniques based on mass spectrometry or molecular biology. While carbapenemases limit the therapeutic options in A. baumannii infections, studies concerning novel beta-lactamase inhibitors offer a new insight into effective therapy.

  1. The strain rate sensitivity and constitutive equations including damage for the superplastic behaviour of 7xxx aluminium alloys

    NASA Astrophysics Data System (ADS)

    Yang, Jian; Boude, Serge; Giraud, Eliane; Dal Santo, Philippe

    2013-05-01

    Superplasticity is a characteristic of certain materials, in particular aluminium alloys, whereby very large deformations (up to 1000 %) can be obtained before fracture under certain conditions. Superplastic forming is therefore the process of deforming a flange under these conditions by applying a variable pressure. The final geometry is obtained when the flange takes the form of a die. In order to deform a material superplastically, the temperature of the material should be approximately a half of the absolute melting point of the material and the strain rate (or flow stress) should remain within a certain range. The most important issues concerning the industrial process are the prediction of the final thickness distribution and the computation of the optimal pressure law to maintain superplastic conditions. Finite element simulations make these predictions possible for industrial components. To ensure the precision of the simulations, it is important to have good knowledge of the material behaviour in the superplastic domain: rheological parameters, grain size, damage law, etc. This paper presents an experimental analysis of the superplastic behaviour of a 7xxx aluminium alloy used for aeronautic applications. The parameters of the constitutive equations (including damage) are identified by using tensile tests, spherical bulging tests and numerical simulations [1, 2]. The performance of the proposed laws [1, 3, and 4] is tested using axisymmetrical geometries with complex shapes by the comparison of numerical simulations and bulge tests.

  2. CpaA a novel protease from Acinetobacter baumannii clinical isolates deregulates blood coagulation.

    PubMed

    Tilley, Derek; Law, Robert; Warren, Sarah; Samis, John A; Kumar, Ayush

    2014-07-01

    Acinetobacter baumannii is an important nosocomial pathogen that displays high antibiotic resistance. It causes a variety of infections including pneumonias and sepsis which may result in disseminated intravascular coagulation. In this work, we identify and characterize a novel secreted, zinc-dependent, metallo-endopeptidase CpaA (coagulation targeting metallo-endopeptidase of Acinetobacter baumannii) which deregulates human blood coagulation in vitro and thus is likely to contribute to A. baumannii virulence. Three quarters of the clinical isolates tested (n = 16) had the cpaA gene; however, it was absent from two type strains, A. baumannii ATCC 17978 and A. baumannii ATCC 19606. The CpaA protein was purified from one clinical isolate and was able to cleave purified factor (F) V and fibrinogen and reduce the coagulation activity of FV in human plasma. CpaA-treated plasma showed reduced clotting activity in contact pathway-activated partial thromboplastin time (aPTT) assays, but increased clotting activity in tissue factor pathway prothrombin time (PT) assays. A significant portion of clinically relevant A. baumannii isolates secrete a protease which targets and deregulates the coagulation system.

  3. Characterization of Acinetobacter baumannii from intensive care units and home care patients in Palermo, Italy.

    PubMed

    Mammina, C; Bonura, C; Aleo, A; Calà, C; Caputo, G; Cataldo, M C; Di Benedetto, A; Distefano, S; Fasciana, T; Labisi, M; Sodano, C; Palma, D M; Giammanco, A

    2011-11-01

    In this study 45 isolates of Acinetobacter baumannii identified from patients in intensive care units of three different hospitals and from pressure ulcers in home care patients in Palermo, Italy, during a 3-month period in 2010, were characterized. All isolates were resistant to at least three classes of antibiotics, but susceptible to colistin and tygecycline. Forty isolates were non-susceptible to carbapenems. Eighteen and two isolates, respectively, carried the bla(OXA-23-like) and the bla(OXA-58-like) genes. One strain carried the VIM-4 gene. Six major rep-PCR subtype clusters were defined, including isolates from different hospitals or home care patients. The sequence type/pulsed field gel electrophoresis group ST2/A included 33 isolates, and ST78/B the remaining 12. ST2 clone proved to be predominant, but a frequent involvement of the ST78 clone was evident.

  4. Isolation and Characterization of Fipronil Degrading Acinetobacter calcoaceticus and Acinetobacter oleivorans from Rhizospheric Zone of Zea mays.

    PubMed

    Uniyal, Shivani; Paliwal, Rashmi; Verma, Megha; Sharma, R K; Rai, J P N

    2016-06-01

    An enrichment culture technique was used for the isolation of bacteria capable of utilizing fipronil as a sole source of carbon and energy. Based on morphological, biochemical characteristics and phylogenetic analysis of 16S rRNA sequence, the bacterial strains were identified as Acinetobacter calcoaceticus and Acinetobacter oleivorans. Biodegradation experiments were conducted in loamy sand soil samples fortified with fipronil (50 µg kg(-1)) and inoculated with Acinetobacter sp. cells (45 × 10(7) CFU mL(-1)) for 90 days. Soil samples were periodically analyzed by gas liquid chromatography equipped with electron capture detector. Biodegradation of fipronil fitted well with the pseudo first-order kinetics, with rate constant value between 0.041 and 0.051 days(-1). In pot experiments, fipronil and its metabolites fipronil sulfide, fipronil sulfone and fipronil amide were found below quantifiable limit in soil and root, shoot and leaves of Zea mays. These results demonstrated that A. calcoaceticus and A. oleivorans may serve as promising strains in the bioremediation of fipronil-contaminated soils.

  5. Nosocomial Acinetobacter baumannii Infections and Changing Antibiotic Resistance.

    PubMed

    Necati Hakyemez, Ismail; Kucukbayrak, Abdulkadir; Tas, Tekin; Burcu Yikilgan, Aslihan; Akkaya, Akcan; Yasayacak, Aliye; Akdeniz, Hayrettin

    2013-09-01

    In the intensive care setting, Acinetobacter baumannii causes ventilator-associated pneumonia and other nosocomial infections that are difficult to treat. Objective of this study was to investigate nosocomial A. baumannii infections and its changing antibiotic resistance. A total of 56 patients diagnosed with A.baumannii infections between January 2009 and December 2011 were included in the study. Diagnosis for nosocomial infections was established according to the CDC (Centers for Disease Control and Prevention) criteria. Identification of the agents isolated was carried out using conventional methods and VITEK 2 automated system, while antibiotic sensitivity testing was performed through VITEK 2 AST-N090 automated system. The most common infection was nosocomial pneumonia by 43%, among which 46% were ventilator-associated pneumonia. Considering all years, the most effective antibiotics on the isolated strains were found as colistin, tigecycline, imipenem and meropenem. However resistance to imipenem and meropenem was observed to increase over years. The issue of increased resistance to antibiotics poses difficulty in treatment of A. baumannii infections which in turn increases the rate of mortality and cost. In order to prevent development of resistance, antibiotics must be used in an appropriate way in accompanied with proper guidance.

  6. Bloodstream infections caused by Acinetobacter species with reduced susceptibility to tigecycline: clinical features and risk factors.

    PubMed

    Park, Ga Eun; Kang, Cheol-In; Cha, Min Kyeong; Cho, Sun Young; Seok, Hyeri; Lee, Ji Hye; Kim, Ji Yeon; Ha, Young Eun; Chung, Doo Ryeon; Peck, Kyong Ran; Lee, Nam Yong; Song, Jae-Hoon

    2017-09-01

    During recent decades, the rates of multidrug resistance, including resistance to carbapenems, have increased dramatically among Acinetobacter species. Tigecycline has activity against multidrug-resistant Acinetobacter spp, including carbapenem-resistant isolates. However, reports of tigecycline-resistant Acinetobacter spp are emerging from different parts of the world. The purpose of this study was to evaluate potential risk factors associated with tigecycline non-susceptible Acinetobacter bacteremia. The medical records of 152 patients with Acinetobacter bacteremia attending Samsung Medical Center between January 2010 and December 2014 were reviewed. Non-susceptibility to tigecycline was defined as a minimum inhibitory concentration (MIC) of tigecycline ≥4μg/ml. Cases were patients with tigecycline non-susceptible Acinetobacter bacteremia and controls were those with tigecycline-susceptible Acinetobacter bacteremia. Of the 152 patients included in the study, 61 (40.1%) had tigecycline non-susceptible Acinetobacter bacteremia (case group). These patients were compared to 91 patients with tigecycline-susceptible Acinetobacter bacteremia (control group). The case group showed high resistance to other antibiotics (>90%) except colistin (6.6%) and minocycline (9.8%) when compared to the control group, which exhibited relatively low resistance to other antibiotics (<50%). Multivariate analysis showed that recent exposure to corticosteroids (minimum 20mg per day for more than 5 days within 2 weeks) (adjusted odds ratio (OR) 2.887, 95% confidence interval (CI) 1.170-7.126) and carbapenems (within 2 weeks) (adjusted OR 4.437, 95% CI 1.970-9.991) were significantly associated with tigecycline non-susceptible Acinetobacter bacteremia. Although prior exposure to tigecycline was more common in the case group than in the control group (9.8%, 6/61 vs. 2.2%, 2/91; p=0.046), this variable was found not to be a significant factor associated with tigecycline non

  7. The Nxsm Recombinant Inbred Strains of Mice: Genetic Profile for 58 Loci Including the Mtv Proviral Loci

    PubMed Central

    Eicher, E. M.; Lee, B. K.

    1990-01-01

    We report the construction of 17 recombinant inbred (RI) strains of mice derived from the progenitor strains NZB/BINRe and SM/J and the typing of this RI strain set, designated NXSM, for 58 loci distributed on 16 autosomes and the X chromosome. Two backcrosses involving NZB/BINJ and SM/J were constructed to confirm chromosomal assignments and determine gene orders suggested from NXSM RI strain data. From these results we recommend that chromosomal assignments and gene orders suggested from analyses of RI strain sets be confirmed using data obtained by other means. We also typed NZB/BINJ and SM/J for mammary tumor proviral (Mtv) loci. Both strains share three previously described Mtv loci: Mtv-7, Mtv-14 and Mtv-17. In addition, NZB/BINJ contains the previously described Mtv-3 and Mtv-9 loci and two new Mtv proviral loci: Mtv-27 located on chromosome (Chr) 1 and Mtv-28 located on the X chromosome. SM/J contains the previously described loci Mtv-6 and Mtv-8. Four LTR, mink cell focus-forming murine leukemia viral loci were identified and mapped: Ltrm-1 on Chr 12, Ltrm-2 on Chr 16, Ltrm-3 on Chr 5, and Ltrm-4 on Chr 13. The Tgn locus was positioned proximal to the Ly-6 locus on Chr 15. PMID:2165966

  8. Comparative Analysis of Acinetobacters: Three Genomes for Three Lifestyles

    PubMed Central

    Vallenet, David; Nordmann, Patrice; Barbe, Valérie; Poirel, Laurent; Mangenot, Sophie; Bataille, Elodie; Dossat, Carole; Gas, Shahinaz; Kreimeyer, Annett; Lenoble, Patricia; Oztas, Sophie; Poulain, Julie; Segurens, Béatrice; Robert, Catherine; Abergel, Chantal; Claverie, Jean-Michel; Raoult, Didier; Médigue, Claudine; Weissenbach, Jean; Cruveiller, Stéphane

    2008-01-01

    Acinetobacter baumannii is the source of numerous nosocomial infections in humans and therefore deserves close attention as multidrug or even pandrug resistant strains are increasingly being identified worldwide. Here we report the comparison of two newly sequenced genomes of A. baumannii. The human isolate A. baumannii AYE is multidrug resistant whereas strain SDF, which was isolated from body lice, is antibiotic susceptible. As reference for comparison in this analysis, the genome of the soil-living bacterium A. baylyi strain ADP1 was used. The most interesting dissimilarities we observed were that i) whereas strain AYE and A. baylyi genomes harbored very few Insertion Sequence elements which could promote expression of downstream genes, strain SDF sequence contains several hundred of them that have played a crucial role in its genome reduction (gene disruptions and simple DNA loss); ii) strain SDF has low catabolic capacities compared to strain AYE. Interestingly, the latter has even higher catabolic capacities than A. baylyi which has already been reported as a very nutritionally versatile organism. This metabolic performance could explain the persistence of A. baumannii nosocomial strains in environments where nutrients are scarce; iii) several processes known to play a key role during host infection (biofilm formation, iron uptake, quorum sensing, virulence factors) were either different or absent, the best example of which is iron uptake. Indeed, strain AYE and A. baylyi use siderophore-based systems to scavenge iron from the environment whereas strain SDF uses an alternate system similar to the Haem Acquisition System (HAS). Taken together, all these observations suggest that the genome contents of the 3 Acinetobacters compared are partly shaped by life in distinct ecological niches: human (and more largely hospital environment), louse, soil. PMID:18350144

  9. Quorum sensing in Acinetobacter: an emerging pathogen.

    PubMed

    Bhargava, Nidhi; Sharma, Prince; Capalash, Neena

    2010-11-01

    Acinetobacter is emerging as one of the major nosocomial infectious pathogens, facilitated by tolerance to desiccation and multidrug resistance. Quorum sensing (autoinducer-receptor mechanism) plays role in biofilm formation in Acinetobacter, though its role in regulation of other virulence factors is yet to be established. Phylogenetic studies indicate that Acinetobacter baumannii is closely related to Burkholderia ambifaria but its quorum sensing genes (abaI and abaR) were acquired horizontally from Halothiobacillus neapolitanus. The prospects of quorum quenching to control the infections caused by Acinetobacter have also been discussed.

  10. Biofilm production and evaluation of antifungal susceptibility amongst clinical Candida spp. isolates, including strains of the Candida parapsilosis complex.

    PubMed

    Melo, Analy S; Bizerra, Fernando C; Freymüller, Edna; Arthington-Skaggs, Beth A; Colombo, Arnaldo L

    2011-04-01

    Candida cells can form biofilms that frequently are sources of infections and are less susceptible to antifungal drugs. Some authors have reported that Candida orthopsilosis and Candida metapsilosis isolates are not able to produce biofilms in vitro and there are no studies available on biofilm susceptibility for these species to antifungals. The aims of this study were to (i) quantify Candida spp. biofilms in vitro, and (ii) test the in vitro susceptibilities of Candida spp. biofilms to fluconazole (FLC) and amphotericin B (AMB). Isolates studied included four Candida albicans, six C. tropicalis, seven C. parapsilosis, eight C. orthopsilosis, and five C. metapsilosis. We compared two different methods to evaluate biofilm production, i.e., crystal violet (CV) staining and XTT-reduction assays (XTT). Scanning electron microscopy (SEM) was used to observe high, medium and low biofilm producing isolates screened by these two methods. To determine the minimum biofilm eradication concentration (MBEC) for FLC and AMB, XTT-reduction assay was used to measure cell metabolic activity. Biofilm quantification by CV and XTT showed that C. tropicalis isolates were the highest biofilm producer, followed by C. albicans, C. parapsilosis, C. orthopsilosis and C. metapsilosis. Examination of SEM images revealed that the extent of biofilms formed by high, medium, and low producers was highly correlated to the results generated by CV assay. Biofilm of all the isolates evaluated were resistant to FLC (MBEC(80) ≥ 256 ug/ml) but, in general, susceptible to AMB, except for six C. parapsilosis strains (MBEC(80) ≥ 8 ug/ml).

  11. Whole genome sequencing and phylogenetic analysis of Bluetongue virus serotype 2 strains isolated in the Americas including a novel strain from the western United States.

    PubMed

    Gaudreault, Natasha N; Mayo, Christie E; Jasperson, Dane C; Crossley, Beate M; Breitmeyer, Richard E; Johnson, Donna J; Ostlund, Eileen N; MacLachlan, N James; Wilson, William C

    2014-07-01

    Bluetongue is a potentially fatal arboviral disease of domestic and wild ruminants that is characterized by widespread edema and tissue necrosis. Bluetongue virus (BTV) serotypes 10, 11, 13, and 17 occur throughout much of the United States, whereas serotype 2 (BTV-2) was previously only detected in the southeastern United States. Since 1998, 10 other BTV serotypes have also been isolated from ruminants in the southeastern United States. In 2010, BTV-2 was identified in California for the first time, and preliminary sequence analysis indicated that the virus isolate was closely related to BTV strains circulating in the southeastern United States. In the current study, the whole genome sequence of the California strain of BTV-2 was compared with those of other BTV-2 strains in the Americas. The results of the analysis suggest co-circulation of genetically distinct viruses in the southeastern United States, and further suggest that the 2010 western isolate is closely related to southeastern strains of BTV. Although it remains uncertain as to how this novel virus was translocated to California, the findings of the current study underscore the need for ongoing surveillance of this economically important livestock disease.

  12. The complete genome and phenome of a community-acquired Acinetobacter baumannii.

    PubMed

    Farrugia, Daniel N; Elbourne, Liam D H; Hassan, Karl A; Eijkelkamp, Bart A; Tetu, Sasha G; Brown, Melissa H; Shah, Bhumika S; Peleg, Anton Y; Mabbutt, Bridget C; Paulsen, Ian T

    2013-01-01

    Many sequenced strains of Acinetobacter baumannii are established nosocomial pathogens capable of resistance to multiple antimicrobials. Community-acquired A. baumannii in contrast, comprise a minor proportion of all A. baumannii infections and are highly susceptible to antimicrobial treatment. However, these infections also present acute clinical manifestations associated with high reported rates of mortality. We report the complete 3.70 Mbp genome of A. baumannii D1279779, previously isolated from the bacteraemic infection of an Indigenous Australian; this strain represents the first community-acquired A. baumannii to be sequenced. Comparative analysis of currently published A. baumannii genomes identified twenty-four accessory gene clusters present in D1279779. These accessory elements were predicted to encode a range of functions including polysaccharide biosynthesis, type I DNA restriction-modification, and the metabolism of novel carbonaceous and nitrogenous compounds. Conversely, twenty genomic regions present in previously sequenced A. baumannii strains were absent in D1279779, including gene clusters involved in the catabolism of 4-hydroxybenzoate and glucarate, and the A. baumannii antibiotic resistance island, known to bestow resistance to multiple antimicrobials in nosocomial strains. Phenomic analysis utilising the Biolog Phenotype Microarray system indicated that A. baumannii D1279779 can utilise a broader range of carbon and nitrogen sources than international clone I and clone II nosocomial isolates. However, D1279779 was more sensitive to antimicrobial compounds, particularly beta-lactams, tetracyclines and sulphonamides. The combined genomic and phenomic analyses have provided insight into the features distinguishing A. baumannii isolated from community-acquired and nosocomial infections.

  13. Towards the complete small RNome of Acinetobacter baumannii

    PubMed Central

    Weiss, Andy; Broach, William H.; Lee, Mackenzie C.

    2016-01-01

    In recent years, the Gram-negative bacterium Acinetobacter baumannii has garnered considerable attention for its unprecedented capacity to rapidly develop resistance to antibacterial therapeutics. This is coupled with the seemingly epidemic emergence of new hyper-virulent strains. Although strain-specific differences for A. baumannii isolates have been well described, these studies have primarily focused on proteinaceous factors. At present, only limited publications have investigated the presence and role of small regulatory RNA (sRNA) transcripts. Herein, we perform such an analysis, describing the RNA-seq-based identification of 78 A. baumannii sRNAs in the AB5075 background. Together with six previously identified elements, we include each of these in a new genome annotation file, which will serve as a tool to investigate regulatory events in this organism. Our work reveals that the sRNAs display high expression, accounting for >50 % of the 20 most strongly expressed genes. Through conservation analysis we identified six classes of similar sRNAs, with one found to be particularly abundant and homologous to regulatory, C4 antisense RNAs found in bacteriophages. These elements appear to be processed from larger transcripts in an analogous manner to the phage C4 molecule and are putatively controlled by two further sRNAs that are strongly antisense to them. Collectively, this study offers a detailed view of the sRNA content of A. baumannii, exposing sequence and structural conservation amongst these elements, and provides novel insight into the potential evolution, and role, of these understudied regulatory molecules. PMID:28348845

  14. Acinetobacter apis sp. nov., isolated from the intestinal tract of a honey bee, Apis mellifera.

    PubMed

    Kim, Pil Soo; Shin, Na-Ri; Kim, Joon Yong; Yun, Ji-Hyun; Hyun, Dong-Wook; Bae, Jin-Woo

    2014-08-01

    A novel Gram-negative, obligate aerobic, non-motile, and both coccobacillus- and bacillus-shaped bacterium, designated strain HYN18(T), was isolated from the intestinal tract of a honey bee (Apis mellifera). The isolate was oxidase-negative and catalase-positive. Strain HYN18(T) showed optimum growth at 25°C, pH 6-7, and in the presence of 1% (w/v) NaCl in trypticase soy broth medium. The isolate was negative for hydrolyses of starch, casein, gelatin and urea, indole production from tryptone and hemolysis on sheep blood agar. A phylogenetic analysis based on the 16S rRNA gene and rpoB gene sequence showed that strain HYN18(T) was most closely related to Acinetobacter nectaris SAP 763.2(T) and A. boissieri SAP 284.1(T) with 98.3% and 98.1% similarity (16S rRNA gene), respectively, and 84.4% similarity with Acinetobacter nectaris SAP 763.2(T) (rpoB gene). The major cellular fatty acids were summed features 3 (comprising C16:1ω7c /C16:1ω6c ), C12:0 and C16:0. The main isoprenoid quinone was ubiquinone-9 (Q-9). The polar lipids of strain HYN18(T) were phosphatidylethanolamine, three unidentified lipids, an unidentified phospholipid and an unidentified glycolipid. The DNA G+C content was 40.6 mol%. DNA-DNA hybridization experiments indicated less than 33 ± 10% relatedness to the closest phylogenetic species, Acinetobacter nectaris SAP 763.2(T). Thus, the phenotypic, phylogenetic and genotypic analyses indicate that strain HYN18(T) is a novel species within the genus Acinetobacter, for which the name Acinetobacter apis is proposed. The type strain is HYN18(T) (=KACC 16906(T) =JCM 18575(T)).

  15. Multidrug resistant Acinetobacter baumannii reaches a new frontier: prosthetic hip joint infection.

    PubMed

    Hischebeth, G T R; Wimmer, M D; Molitor, E; Seifert, H; Gravius, S; Bekeredjian-Ding, I

    2015-02-01

    Acinetobacter baumannii is an emerging nosocomial pathogen primarily in countries with a high prevalence of multidrug resistance. Here we report the detection of a bla OXA23 carbapenemase-producing A. baumannii strain in a German patient with prosthetic hip joint infection following several hip joint surgeries but no history of foreign travel.

  16. Colistin methanesulfonate against multidrug-resistant Acinetobacter baumannii in an in vitro pharmacodynamic model.

    PubMed

    Kroeger, Lisa A; Hovde, Laurie B; Mitropoulos, Isaac F; Schafer, Jeremy; Rotschafer, John C

    2007-09-01

    Using an in vitro pharmacodynamic model, a multidrug-resistant strain of Acinetobacter baumannii was exposed to colistin methanesulfonate alone and in combination with ceftazidime. Pre- and postexposure colistin sulfate MICs were determined. A single daily dose of colistin methanesulfonate combined with continuous-infusion ceftazidime prevented regrowth and postexposure MIC increases.

  17. Draft Genome Sequences of Clinical Isolates of Multidrug-Resistant Acinetobacter baumannii

    PubMed Central

    Erickson, Keesha E.; Madinger, Nancy E.

    2017-01-01

    ABSTRACT We report here the draft genome sequences of two clinically isolated Acinetobacter baumannii strains. These samples were obtained from patients at the University of Colorado Hospital in 2007 and 2013 and encode an estimated 20 and 13 resistance genes, respectively. PMID:28153899

  18. Chemotherapy of Rodent Malaria Evaluation of Drug Action against Normal and Resistant Strains, Including Exo-erythrocytic Stages

    DTIC Science & Technology

    1978-12-01

    malaria strains that are being employed in this work, and a shortage of small animal accommodation pending reconstruction work to improve our animal rooms...intervals thereafter) and the second was the possible effect of host immunity on parasitaemia in animals which were repeatedly challenged with infected...results were due tc artefacts or to a change in the chloroquine sensitivity of the parasite due to the abnormally high temperature in the animal house

  19. Molecular Epidemiology and Characterization of Genotypes of Acinetobacter baumannii Isolates from Regions of South China.

    PubMed

    Ying, Jun; Lu, Junwan; Zong, Li; Li, Ailing; Pan, Ruowang; Cheng, Cong; Li, Kunpeng; Chen, Liqiang; Ying, Jianchao; Tou, Huifen; Zhu, Chuanxin; Xu, Teng; Yi, Huiguang; Li, Jinsong; Ni, Liyan; Xu, Zuyuan; Bao, Qiyu; Li, Peizhen

    2016-05-20

    The aim of this study was to analyze the molecular epidemiologic characteristics of Acinetobacter baumannii. A total of 398 isolates were collected in 7 regions of South China from January to June of 2012. Drug sensitivity was tested toward 15 commonly used antibiotics; thus, 146 multi-drug-resistant strains (resistant to more than 7 drugs) were identified, representing 36.7% of all isolates. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used for molecular subtyping. According to the PFGE results (with a cutoff of 70% similarity for the DNA electrophoretic bands), 146 strains were subdivided into 15 clusters, with cluster A being the largest (33.6%, distributed in all districts except Jiaxing). Cluster B was also widespread and included 14.4% of all strains. In addition, MLST results revealed 11 sequence types (ST), with ST208 being the most prevalent, followed by ST191 and ST729. Furthermore, 4 novel alleles and 6 novel STs were identified. Our results showed that multi-drug-resistant A. baumannii in South China shares the origin with other widespread strains in other countries. The nosocomial infections caused by A. baumannii have been severe in South China. Continuous monitoring and judicious antibiotic use are required.

  20. Acinetobacter baumannii: An Emerging and Important Pathogen

    PubMed Central

    Alsan, Marcella; Klompas, Michael

    2016-01-01

    Objective To review the clinical significance, management, and control of Acinetobacter infections. Methods Literature review. Results Acinetobacter infections have become a major cause of hospital-acquired infections worldwide. Acinetobacter is noted for its ability to survive for long periods on hospital surfaces and equipment, its predilection to develop resistance to multiple antibiotics, its affinity to cause serious infections in critically ill patients, and many well described outbreaks attributable to contamination of a common source. The crude ICU mortality is approximately 40%. Rigorous antibiotic stewardship and infection control measures are critical to prevent the spread of multidrug-resistant Acinetobacter infections. There is also a pressing need for new therapeutic options. Conclusion Acinetobacter is an emerging pathogen of increasing significance. PMID:26966345

  1. Acinetobacter baumannii: Emergence of a Successful Pathogen

    PubMed Central

    Peleg, Anton Y.; Seifert, Harald; Paterson, David L.

    2008-01-01

    Acinetobacter baumannii has emerged as a highly troublesome pathogen for many institutions globally. As a consequence of its immense ability to acquire or upregulate antibiotic drug resistance determinants, it has justifiably been propelled to the forefront of scientific attention. Apart from its predilection for the seriously ill within intensive care units, A. baumannii has more recently caused a range of infectious syndromes in military personnel injured in the Iraq and Afghanistan conflicts. This review details the significant advances that have been made in our understanding of this remarkable organism over the last 10 years, including current taxonomy and species identification, issues with susceptibility testing, mechanisms of antibiotic resistance, global epidemiology, clinical impact of infection, host-pathogen interactions, and infection control and therapeutic considerations. PMID:18625687

  2. The Genomic Scrapheap Challenge; Extracting Relevant Data from Unmapped Whole Genome Sequencing Reads, Including Strain Specific Genomic Segments, in Rats

    PubMed Central

    van der Weide, Robin H.; Simonis, Marieke; Hermsen, Roel; Toonen, Pim; Cuppen, Edwin; de Ligt, Joep

    2016-01-01

    Unmapped next-generation sequencing reads are typically ignored while they contain biologically relevant information. We systematically analyzed unmapped reads from whole genome sequencing of 33 inbred rat strains. High quality reads were selected and enriched for biologically relevant sequences; similarity-based analysis revealed clustering similar to previously reported phylogenetic trees. Our results demonstrate that on average 20% of all unmapped reads harbor sequences that can be used to improve reference genomes and generate hypotheses on potential genotype-phenotype relationships. Analysis pipelines would benefit from incorporating the described methods and reference genomes would benefit from inclusion of the genomic segments obtained through these efforts. PMID:27501045

  3. The Genomic Scrapheap Challenge; Extracting Relevant Data from Unmapped Whole Genome Sequencing Reads, Including Strain Specific Genomic Segments, in Rats.

    PubMed

    van der Weide, Robin H; Simonis, Marieke; Hermsen, Roel; Toonen, Pim; Cuppen, Edwin; de Ligt, Joep

    2016-01-01

    Unmapped next-generation sequencing reads are typically ignored while they contain biologically relevant information. We systematically analyzed unmapped reads from whole genome sequencing of 33 inbred rat strains. High quality reads were selected and enriched for biologically relevant sequences; similarity-based analysis revealed clustering similar to previously reported phylogenetic trees. Our results demonstrate that on average 20% of all unmapped reads harbor sequences that can be used to improve reference genomes and generate hypotheses on potential genotype-phenotype relationships. Analysis pipelines would benefit from incorporating the described methods and reference genomes would benefit from inclusion of the genomic segments obtained through these efforts.

  4. Anticipating the Unpredictable: A Review of Antimicrobial Stewardship and Acinetobacter Infections.

    PubMed

    Wenzler, Eric; Goff, Debra A; Humphries, Romney; Goldstein, Ellie J C

    2017-06-01

    Acinetobacter remains one of the most challenging pathogens in the field of infectious diseases owing primarily to the uniqueness and multiplicity of its resistance mechanisms. This resistance often leads to devastatingly long delays in time to appropriate therapy and increased mortality for patients afflicted with Acinetobacter infections. Selecting appropriate empiric and definitive antibacterial therapy for Acinetobacter is further complicated by the lack of reliability in commercial antimicrobial susceptibility testing devices and limited breakpoint interpretations for available agents. Existing treatment options for infections due to Acinetobacter are limited by a lack of robust efficacy and safety data along with concerns regarding appropriate dosing, pharmacokinetic/pharmacodynamic targets, and toxicity. Antimicrobial stewardship programs are essential to combat this unpredictable pathogen through use of infection prevention, rapid diagnostics, antibiogram-optimized treatment regimens, and avoidance of overuse of antimicrobials. The drug development pipeline includes several agents with encouraging in vitro activity against Acinetobacter, but their place in therapy and contribution to the armamentarium against this pathogen remain to be defined. The objective of this review is to highlight the unique challenge of treating infections due to Acinetobacter and summarize recent literature regarding optimal antimicrobial treatment for this pathogen. The drug development pipeline is also explored for future potentially effective treatment options.

  5. Influence of probiotics, included in peanut butter, on the fate of selected Salmonella and Listeria strains under simulated gastrointestinal conditions.

    PubMed

    Klu, Y A K; Chen, J

    2016-04-01

    This study observed the behaviour of probiotics and selected bacterial pathogens co-inoculated into peanut butter during gastrointestinal simulation. Peanut butter homogenates co-inoculated with Salmonella/Listeria strains (5 log CFU ml(-1) ) and lyophilized or cultured probiotics (9 log CFU ml(-1) ) were exposed to simulated gastrointestinal conditions for 24 h at 37°C. Sample pH, titratable acidity and pathogen populations were determined. Agar diffusion assay was performed to assess the inhibitory effect of probiotic culture supernatants with either natural (3·80 (Lactobacillus), 3·78 (Bifidobacteirum) and 5·17 (Streptococcus/Lactococcus)) or neutralized (6·0) pH. Antibacterial effect of crude bacteriocin extracts were also evaluated against the pathogens. After 24 h, samples with probiotics had lower pH and higher titratable acidity than those without probiotics. The presence of probiotics caused a significant reduction (P < 0·05) in pathogen populations. Supernatants of Bifidobacterium and Lactobacillus cultures inhibited pathogen growth; however, the elevation of pH diminished their antibacterial activities. Crude bacteriocin extracts had a strain-specific inhibitory effect only towards Listeria monocytogenes. Probiotics in 'peanut butter' survived simulated gastrointestinal conditions and inhibited the growth of Salmonella/Listeria. Peanut butter is a plausible carrier to deliver probiotics to improve the gastrointestinal health of children in developing countries. © 2016 The Society for Applied Microbiology.

  6. Modeling the Nonlinear, Strain Rate Dependent Deformation of Shuttle Leading Edge Materials with Hydrostatic Stress Effects Included

    NASA Technical Reports Server (NTRS)

    Goldberg, Robert K.; Carney, Kelly S.

    2004-01-01

    An analysis method based on a deformation (as opposed to damage) approach has been developed to model the strain rate dependent, nonlinear deformation of woven ceramic matrix composites, such as the Reinforced Carbon Carbon (RCC) material used on the leading edges of the Space Shuttle. In the developed model, the differences in the tension and compression deformation behaviors have also been accounted for. State variable viscoplastic equations originally developed for metals have been modified to analyze the ceramic matrix composites. To account for the tension/compression asymmetry in the material, the effective stress and effective inelastic strain definitions have been modified. The equations have also been modified to account for the fact that in an orthotropic composite the in-plane shear response is independent of the stiffness in the normal directions. The developed equations have been implemented into LS-DYNA through the use of user defined subroutines (UMATs). Several sample qualitative calculations have been conducted, which demonstrate the ability of the model to qualitatively capture the features of the deformation response present in woven ceramic matrix composites.

  7. Modeling the Nonlinear, Strain Rate Dependent Deformation of Woven Ceramic Matrix Composites With Hydrostatic Stress Effects Included

    NASA Technical Reports Server (NTRS)

    Goldberg, Robert K.; Carney, Kelly S.

    2004-01-01

    An analysis method based on a deformation (as opposed to damage) approach has been developed to model the strain rate dependent, nonlinear deformation of woven ceramic matrix composites with a plain weave fiber architecture. In the developed model, the differences in the tension and compression response have also been considered. State variable based viscoplastic equations originally developed for metals have been modified to analyze the ceramic matrix composites. To account for the tension/compression asymmetry in the material, the effective stress and effective inelastic strain definitions have been modified. The equations have also been modified to account for the fact that in an orthotropic composite the in-plane shear stiffness is independent of the stiffness in the normal directions. The developed equations have been implemented into a commercially available transient dynamic finite element code, LS-DYNA, through the use of user defined subroutines (UMATs). The tensile, compressive, and shear deformation of a representative plain weave woven ceramic matrix composite are computed and compared to experimental results. The computed values correlate well to the experimental data, demonstrating the ability of the model to accurately compute the deformation response of woven ceramic matrix composites.

  8. Iron acquisition functions expressed by the human pathogen Acinetobacter baumannii.

    PubMed

    Zimbler, Daniel L; Penwell, William F; Gaddy, Jennifer A; Menke, Sharon M; Tomaras, Andrew P; Connerly, Pamela L; Actis, Luis A

    2009-02-01

    Acinetobacter baumannii is a gram-negative bacterium that causes serious infections in compromised patients. More recently, it has emerged as the causative agent of severe infections in military personnel wounded in Iraq and Afghanistan. This pathogen grows under a wide range of conditions including iron-limiting conditions imposed by natural and synthetic iron chelators. Initial studies using the type strain 19606 showed that the iron proficiency of this pathogen depends on the expression of the acinetobactin-mediated iron acquisition system. More recently, we have observed that hemin but not human hemoglobin serves as an iron source when 19606 isogenic derivatives affected in acinetobactin transport and biosynthesis were cultured under iron-limiting conditions. This finding is in agreement with the observation that the genome of the strain 17978 has a gene cluster coding for putative hemin-acquisition functions, which include genes coding for putative hemin utilization functions and a TonBExbBD energy transducing system. This system restored enterobactin biosynthesis in an E. coli ExbBD deficient strain but not when introduced into a TonB mutant. PCR and Southern blot analyses showed that this hemin-utilization gene cluster is also present in the 19606 strain. Analysis of the 17978 genome also showed that this strain harbors genes required for acinetobactin synthesis and transport as well as a gene cluster that could code for additional iron acquisition functions. This hypothesis is in agreement with the fact that the inactivation of the basD acinetobactin biosynthetic gene did not affect the growth of A. baumannii 17978 cells under iron-chelated conditions. Interestingly, this second iron uptake gene cluster is flanked by perfect inverted repeats and includes transposase genes that are expressed transcriptionally. Also interesting is the observation that this additional cluster could not be detected in the type strain 19606, an observation that suggests some

  9. Essential Biological Processes of an Emerging Pathogen: DNA Replication, Transcription, and Cell Division in Acinetobacter spp.

    PubMed Central

    Robinson, Andrew; Brzoska, Anthony J.; Turner, Kylie M.; Withers, Ryan; Harry, Elizabeth J.; Lewis, Peter J.; Dixon, Nicholas E.

    2010-01-01

    Summary: Within the last 15 years, members of the bacterial genus Acinetobacter have risen from relative obscurity to be among the most important sources of hospital-acquired infections. The driving force for this has been the remarkable ability of these organisms to acquire antibiotic resistance determinants, with some strains now showing resistance to every antibiotic in clinical use. There is an urgent need for new antibacterial compounds to combat the threat imposed by Acinetobacter spp. and other intractable bacterial pathogens. The essential processes of chromosomal DNA replication, transcription, and cell division are attractive targets for the rational design of antimicrobial drugs. The goal of this review is to examine the wealth of genome sequence and gene knockout data now available for Acinetobacter spp., highlighting those aspects of essential systems that are most suitable as drug targets. Acinetobacter spp. show several key differences from other pathogenic gammaproteobacteria, particularly in global stress response pathways. The involvement of these pathways in short- and long-term antibiotic survival suggests that Acinetobacter spp. cope with antibiotic-induced stress differently from other microorganisms. PMID:20508250

  10. Antibiotic Resistance Determinant-Focused Acinetobacter baumannii Vaccine Designed Using Reverse Vaccinology

    PubMed Central

    Ni, Zhaohui; Chen, Yan; Ong, Edison; He, Yongqun

    2017-01-01

    As one of the most influential and troublesome human pathogens, Acinetobacter baumannii (A. baumannii) has emerged with many multidrug-resistant strains. After collecting 33 complete A. baumannii genomes and 84 representative antibiotic resistance determinants, we used the Vaxign reverse vaccinology approach to predict classical type vaccine candidates against A. baumannii infections and new type vaccine candidates against antibiotic resistance. Our genome analysis identified 35 outer membrane or extracellular adhesins that are conserved among all 33 genomes, have no human protein homology, and have less than 2 transmembrane helices. These 35 antigens include 11 TonB dependent receptors, 8 porins, 7 efflux pump proteins, and 2 fimbrial proteins (FilF and CAM87009.1). CAM86003.1 was predicted to be an adhesin outer membrane protein absent from 3 antibiotic-sensitive strains and conserved in 21 antibiotic-resistant strains. Feasible anti-resistance vaccine candidates also include one extracellular protein (QnrA), 3 RND type outer membrane efflux pump proteins, and 3 CTX-M type β-lactamases. Among 39 β-lactamases, A. baumannii CTX-M-2, -5, and -43 enzymes are predicted as adhesins and better vaccine candidates than other β-lactamases to induce preventive immunity and enhance antibiotic treatments. This report represents the first reverse vaccinology study to systematically predict vaccine antigen candidates against antibiotic resistance for a microbial pathogen. PMID:28230771

  11. Antibiotic Resistance Determinant-Focused Acinetobacter baumannii Vaccine Designed Using Reverse Vaccinology.

    PubMed

    Ni, Zhaohui; Chen, Yan; Ong, Edison; He, Yongqun

    2017-02-21

    As one of the most influential and troublesome human pathogens, Acinetobacter baumannii (A. baumannii) has emerged with many multidrug-resistant strains. After collecting 33 complete A. baumannii genomes and 84 representative antibiotic resistance determinants, we used the Vaxign reverse vaccinology approach to predict classical type vaccine candidates against A. baumannii infections and new type vaccine candidates against antibiotic resistance. Our genome analysis identified 35 outer membrane or extracellular adhesins that are conserved among all 33 genomes, have no human protein homology, and have less than 2 transmembrane helices. These 35 antigens include 11 TonB dependent receptors, 8 porins, 7 efflux pump proteins, and 2 fimbrial proteins (FilF and CAM87009.1). CAM86003.1 was predicted to be an adhesin outer membrane protein absent from 3 antibiotic-sensitive strains and conserved in 21 antibiotic-resistant strains. Feasible anti-resistance vaccine candidates also include one extracellular protein (QnrA), 3 RND type outer membrane efflux pump proteins, and 3 CTX-M type β-lactamases. Among 39 β-lactamases, A. baumannii CTX-M-2, -5, and -43 enzymes are predicted as adhesins and better vaccine candidates than other β-lactamases to induce preventive immunity and enhance antibiotic treatments. This report represents the first reverse vaccinology study to systematically predict vaccine antigen candidates against antibiotic resistance for a microbial pathogen.

  12. Activity of Debio1452, a FabI Inhibitor with Potent Activity against Staphylococcus aureus and Coagulase-Negative Staphylococcus spp., Including Multidrug-Resistant Strains

    PubMed Central

    Rhomberg, Paul R.; Kaplan, Nachum; Jones, Ronald N.; Farrell, David J.

    2015-01-01

    Staphylococcus aureus and coagulase-negative staphylococci (CoNS) are responsible for a wide variety of human infections. The investigational antibacterial Debio1450 (previously AFN-1720), a prodrug of Debio1452 (previously AFN-1252), specifically targets staphylococci without significant activity against other Gram-positive or Gram-negative species. Debio1452 inhibits FabI, an enzyme critical to fatty acid biosynthesis in staphylococci. The activity of Debio1452 against CoNS, methicillin-susceptible S. aureus (MSSA), and methicillin-resistant S. aureus (MRSA), including significant clones, was determined. A globally diverse collection of 574 patient isolates from 35 countries was tested that included CoNS (6 species, 103 strains), MSSA (154 strains), MRSA (163 strains), and molecularly characterized strains (including spa-typed MRSA clones; 154 strains). The isolates were tested for susceptibility by CLSI broth microdilution methods against Debio1452 and 10 comparators. The susceptibility rates for the comparators were determined using CLSI and EUCAST breakpoint criteria. All S. aureus and CoNS strains were inhibited by Debio1452 concentrations of ≤0.12 and ≤0.5 μg/ml, respectively. The MIC50s for MSSA, MRSA, and molecularly characterized MRSA strains were 0.004 μg/ml, and the MIC90s ranged from 0.008 to 0.03 μg/ml. The MICs were higher for the CoNS isolates (MIC50/90, 0.015/0.12 μg/ml). Among S. aureus strains, resistance was common for erythromycin (61.6%), levofloxacin (49.0%), clindamycin (27.6%), tetracycline (15.7%), and trimethoprim-sulfamethoxazole (7.0%). Debio1452 demonstrated potent activity against MSSA, MRSA, and CoNS. Debio1452 showed significantly greater activity overall (MIC50, 0.004 μg/ml) than the other agents tested against these staphylococcal species, which included dominant MRSA clones and strains resistant to currently utilized antimicrobial agents. PMID:25691627

  13. High prevalence of the PER-1 gene among carbapenem-resistant Acinetobacter baumannii in Riyadh, Saudi Arabia.

    PubMed

    Aly, M M; Abu Alsoud, N M; Elrobh, M S; Al Johani, S M; Balkhy, H H

    2016-11-01

    The prevalence of carbapenem-resistant Acinetobacter baumannii in Saudi Arabia and their resistance genetic mechanisms are yet to be identified. We studied the prevalence and genetic diversity of extended-spectrum beta-lactamase genes, particularly the PER-1 gene, among carbapenem-resistant A. baumannii strains from patients at a tertiary care hospital in Riyadh, Saudi Arabia between 2006 and 2014. Fresh subcultured samples were tested for antimicrobial susceptibility minimum inhibitory concentration (MIC). Total genomic DNA was extracted from each isolate and further used for polymerase chain reaction (PCR) genotyping, sequence-based typing (SBT) of PER-1 and OXA-51-like gene, and multilocus sequence typing (MLST) of positive isolates. Randomly selected clinical isolates (n = 100) were subjected to MLST. A total of 503 isolates were characterized as multidrug-resistant (MDR) using the MIC. Isolates were further PCR tested for bla -TEM and bla -PER-1 resistance genes (n = 503). The genotyping results showed that 68/503 (14 %) isolates were positive to bla TEM. The genotyping results of PER-1-like genes showed that 384/503 (76.3 %) were positive among MDR Acinetobacter isolates. Based on SBT, the majority of these isolates were clustered into three main groups including isolates harboring PER-1: AB11 (bla -PER-1), isolate AB16 (bla -PER-1), and, finally, the plasmid pAB154 (bla -PER-7). Remarkably, many isolates were concealing the PER-1 gene and harboring the TEM resistance genes as well. MLST results for selected isolates (n = 100) identified four main sequence types (STs: 2, 19, 20, and 25) and four novel isolates (ST 486-489). We report 76.3 % prevalence of the PER-1 resistance gene among Acinetobacter clinical isolates from Riyadh, Saudi Arabia. Further work is needed to explore the clinical risks and patient outcome with such resistance related to healthcare-associated infections and investigate the genetic and molecular mechanisms that confer the MDR

  14. Evolution of Carbapenem-Resistant Acinetobacter baumannii Revealed through Whole-Genome Sequencing and Comparative Genomic Analysis

    PubMed Central

    Li, Henan; Liu, Fei; Zhang, Yawei; Wang, Xiaojuan; Zhao, Chunjiang; Chen, Hongbin; Zhang, Feifei; Zhu, Baoli

    2014-01-01

    Acinetobacter baumannii is a globally important nosocomial pathogen characterized by an evolving multidrug resistance. A total of 35 representative clinical A. baumannii strains isolated from 13 hospitals in nine cities in China from 1999 to 2011, including 32 carbapenem-resistant and 3 carbapenem-susceptible A. baumannii strains, were selected for whole-genome sequencing and comparative genomic analysis. Phylogenetic analysis revealed that the earliest strain, strain 1999BJAB11, and two strains isolated in Zhejiang Province in 2004 were the founder strains of carbapenem-resistant A. baumannii. Ten types of AbaR resistance islands were identified, and a previously unreported AbaR island, which comprised a two-component response regulator, resistance-related proteins, and RND efflux system proteins, was identified in two strains isolated in Zhejiang in 2004. Multiple transposons or insertion sequences (ISs) existed in each strain, and these gradually tended to diversify with evolution. Some of these IS elements or transposons were the first to be reported, and most of them were mainly found in strains from two provinces. Genome feature analysis illustrated diversified resistance genes, surface polysaccharides, and a restriction-modification system, even in strains that were phylogenetically and epidemiologically very closely related. IS-mediated deletions were identified in the type VI secretion system region, the csuE region, and core lipooligosaccharide (LOS) loci. Recombination occurred in the heme utilization region, and intrinsic resistance genes (blaADC and blaOXA-51-like variants) and three novel blaOXA-51-like variants (blaOXA-424, blaOXA-425, and blaOXA-426) were identified. Our results could improve the understanding of the evolutionary processes that contribute to the emergence of carbapenem-resistant A. baumannii strains and help elucidate the molecular evolutionary mechanism in A. baumannii. PMID:25487793

  15. Iron and Acinetobacter baumannii Biofilm Formation

    PubMed Central

    Gentile, Valentina; Frangipani, Emanuela; Bonchi, Carlo; Minandri, Fabrizia; Runci, Federica; Visca, Paolo

    2014-01-01

    Acinetobacter baumannii is an emerging nosocomial pathogen, responsible for infection outbreaks worldwide. The pathogenicity of this bacterium is mainly due to its multidrug-resistance and ability to form biofilm on abiotic surfaces, which facilitate long-term persistence in the hospital setting. Given the crucial role of iron in A. baumannii nutrition and pathogenicity, iron metabolism has been considered as a possible target for chelation-based antibacterial chemotherapy. In this study, we investigated the effect of iron restriction on A. baumannii growth and biofilm formation using different iron chelators and culture conditions. We report substantial inter-strain variability and growth medium-dependence for biofilm formation by A. baumannii isolates from veterinary and clinical sources. Neither planktonic nor biofilm growth of A. baumannii was affected by exogenous chelators. Biofilm formation was either stimulated by iron or not responsive to iron in the majority of isolates tested, indicating that iron starvation is not sensed as an overall biofilm-inducing stimulus by A. baumannii. The impressive iron withholding capacity of this bacterium should be taken into account for future development of chelation-based antimicrobial and anti-biofilm therapies. PMID:25438019

  16. Comparison of rpoB gene sequencing, 16S rRNA gene sequencing, gyrB multiplex PCR, and the VITEK2 system for identification of Acinetobacter clinical isolates.

    PubMed

    Lee, Min Jung; Jang, Sook Jin; Li, Xue Min; Park, Geon; Kook, Joong-Ki; Kim, Min Jung; Chang, Young-Hyo; Shin, Jong Hee; Kim, Soo Hyun; Kim, Dong-Min; Kang, Seong-Ho; Moon, Dae-Soo

    2014-01-01

    Since accurate identification of species is necessary for proper treatment of Acinetobacter infections, we compared the performances of 4 bacterial identification methods using 167 Acinetobacter clinical isolates to identify the best identification method. To secure more non-baumannii Acinetobacter (NBA) strains as target strains, we first identified Acinetobacter baumannii in a total of 495 Acinetobacter clinical isolates identified using the VITEK 2 system. Because 371 of 495 strains were identified as A. baumannii using gyrB multiplex 1 PCR and blaOXA51-like PCR, we performed rpoB gene sequencing and 16S rRNA gene sequencing on remaining 124 strains belonging to NBA and 52 strains of A. baumannii. For identification of Acinetobacter at the species level, the accuracy rates of rpoB gene sequencing, 16S rRNA gene sequencing, gyrB multiplex PCR, and the VITEK 2 were 98.2%, 93.4%, 77.2%, and 35.9%, respectively. The gyrB multiplex PCR seems to be very useful for the detection of ACB complex because its concordance rates to the final identification of strains of ACB complex were 100%. Both the rpoB gene sequencing and the 16S rRNA gene sequencing may be useful in identifying Acinetobacter. © 2013.

  17. Wide spread of OXA-23-producing carbapenem-resistant Acinetobacter baumannii belonging to clonal complex II in different hospitals in Lebanon.

    PubMed

    Al Atrouni, Ahmad; Hamze, Monzer; Jisr, Tamima; Lemarié, Carole; Eveillard, Matthieu; Joly-Guillou, Marie-Laure; Kempf, Marie

    2016-11-01

    To investigate the molecular epidemiology of Acinetobacter baumannii strains isolated from different hospitals in Lebanon. A total of 119 non-duplicate Acinetobacter strains were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and partial rpoB gene sequencing. Antibiotic susceptibility testing was performed by disc diffusion method and all identified carbapenem-resistant isolates were investigated by PCR assays for the presence of the carbapenemase-encoding genes. Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) were used for molecular typing. Of the 119 A. baumannii isolates, 76.5% were resistant to carbapenems. The most common carbapenemase was the OXA-23-type, found in 82 isolates. The study of population structure using MLST revealed the presence of 30 sequence types (STs) including 18 new ones, with ST2 being the most commonly detected, accounting for 61% of the isolates typed. PFGE performed on all strains of ST2 identified a major cluster of 53 isolates, in addition to three other minor clusters and ten unique profiles. This study highlights the wide dissemination of highly related OXA-23-producing carbapenem-resistant A. baumannii belonging to the international clone II in Lebanon. Thus, appropriate infection control measures are recommended in order to control the geographical spread of this clone in this country. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Whole genome sequence analysis of circulating Bluetongue virus serotype 11 strains from the United States including two domestic canine isolates.

    PubMed

    Gaudreault, Natasha N; Jasperson, Dane C; Dubovi, Edward J; Johnson, Donna J; Ostlund, Eileen N; Wilson, William C

    2015-07-01

    Bluetongue virus (BTV) is a vector-transmitted pathogen that typically infects and causes disease in domestic and wild ruminants. BTV is also known to infect domestic canines as discovered when dogs were vaccinated with a BTV-contaminated vaccine. Canine BTV infections have been documented through serological surveys, and natural infection by the Culicoides vector has been suggested. The report of isolation of BTV serotype 11 (BTV-11) from 2 separate domestic canine abortion cases in the states of Texas in 2011 and Kansas in 2012, were apparently unrelated to BTV-contaminated vaccination or consumption of BTV-contaminated raw meat as had been previously speculated. To elucidate the origin and relationship of these 2 domestic canine BTV-11 isolates, whole genome sequencing was performed. Six additional BTV-11 field isolates from Texas, Florida, and Washington, submitted for diagnostic investigation during 2011 and 2013, were also fully sequenced and analyzed. The phylogenetic analysis indicates that the BTV-11 domestic canine isolates are virtually identical, and both share high identity with 2 BTV-11 isolates identified from white-tailed deer in Texas in 2011. The results of the current study further support the hypothesis that a BTV-11 strain circulating in the Midwestern states could have been transmitted to the dogs by the infected Culicoides vector. Our study also expands the short list of available BTV-11 sequences, which may aid BTV surveillance and epidemiology.

  19. The sensor kinase BfmS mediates virulence in Acinetobacter baumannii.

    PubMed

    Liou, Ming-Li; Soo, Po-Chi; Ling, Siao-Ru; Kuo, Han-Yueh; Tang, Chuan Yi; Chang, Kai-Chih

    2014-08-01

    BfmR, the response regulator component of the two-component system BfmRS, has important roles in biofilm formation and cellular morphology of Acinetobacter baumannii. Until now, the contribution of the sensor kinase BfmS to the virulence of this bacterium remains unknown. In this study, a bfmS knockout and complementation studies were performed to clarify the role of BfmS in A. baumannii virulence. We constructed a bfmS knockout mutant in the A. baumannii 17978 type strain by transposon inactivation. To clarify the role of bfmS in A. baumannii virulence, the biofilm formation, adherence ability to eukaryotic cells, serum resistance, and antibiotic susceptibility tests were performed in A. baumannii 17978 and its derivative knockout and complementation strains. The bfmS knockout displayed a reduction in biofilm formation, loss of adherence to eukaryotic cells, and greater sensitivity to serum killing compared with the parent strain. Proteomic analysis of culture supernatants revealed that the release of outer membrane proteins (Omps), including CarO and outer membrane protein A (OmpA), was associated with the inactivation of BfmS in A. baumannii. This study is the first to demonstrate that the pathway regulated by the sensor kinase BfmS is associated with biofilm formation, adherence to biotic surfaces, serum resistance, and antibiotic susceptibility, which may be associated with the release of Omps in A. baumannii. Copyright © 2013. Published by Elsevier B.V.

  20. Structure of the K2 capsule associated with the KL2 gene cluster of Acinetobacter baumannii.

    PubMed

    Kenyon, Johanna J; Marzaioli, Alberto M; Hall, Ruth M; De Castro, Cristina

    2014-06-01

    The repeat unit structure of the K2 capsule from an extensively antibiotic-resistant Acinetobacter baumannii global clone 2 (GC2) strain was determined. The oligosaccharide contains three simple sugars, d-glucopyranose, d-galatopyranose and N-acetyl-d-galactosamine, and the complex sugar, 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno-non-2-ulosonic acid (Pse5Ac7Ac or pseudaminic acid), which has not previously been reported in any A. baumannii capsule. The strain was found to carry all the genes required for the synthesis of the sugars and construction of the K2 structure. The linkages catalyzed by the initiating transferase, three glycosyltransferases and the Wzy polymerase were also predicted. Examination of publicly available A. baumannii genome sequences revealed that the same gene cluster, KL2, often occurs in extensively antibiotic-resistant GC2 isolates and in further strain types. The gene module responsible for the synthesis of pseudaminic acid was also detected in four other K loci. A related module including genes for an acylated relative of pseudaminic acid was also found in two new KL types. A polymerase chain reaction scheme was developed to detect all modules containing genes for sugars based on pseudaminic acid and to specifically detect KL2.

  1. Effect of Preload Alterations on Left Ventricular Systolic Parameters Including Speckle-Tracking Echocardiography Radial Strain During General Anesthesia.

    PubMed

    Weber, Ulrike; Base, Eva; Ristl, Robin; Mora, Bruno

    2015-08-01

    Frequently used parameters for evaluation of left ventricular systolic function are load-sensitive. However, the impact of preload alterations on speckle-tracking echocardiographic parameters during anesthesia has not been validated. Therefore, two-dimensional (2D) speckle-tracking echocardiography radial strain (RS) was assessed during general anesthesia, simulating 3 different preload conditions. Single-center prospective observational study. University hospital. Thirty-three patients with normal left ventricular systolic function undergoing major surgery. Transgastric views of the midpapillary level of the left ventricle were acquired at 3 different positions. Fractional shortening (FS), fractional area change (FAC), and 2D speckle-tracking echocardiography RS were analyzed in the transgastric midpapillary view. Considerable correlation above 0.5 was found for FAC and FS in the zero and Trendelenburg positions (r = 0.629, r = 0.587), and for RS and FAC in the anti-Trendelenburg position (r = 0.518). In the repeated-measures analysis, significant differences among the values measured at the 3 positions were found for FAC and FS. For FAC, there were differences up to 2.8 percentage points between the anti-Trendelenburg position and the other 2 positions. For FS, only the difference between position zero and anti-Trendelenburg was significant, with an observed change of 1.66. Two-dimensional RS was not significantly different at all positions, with observed changes below 1 percentage point. Alterations in preload did not result in clinically relevant changes of RS, FS, or FAC. Observed changes for RS were smallest; however, the variation of RS was larger than that of FS or FAC. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Novel Oxadiazole Thioglycosides as Potential Anti-Acinetobacter Agents

    PubMed Central

    Akbari Dilmaghani, Karim; Nasuhi Pur, Fazel; Mahammad pour, Majid; Mahammad nejad, Jafar

    2016-01-01

    The glycosylation of 1,3,4-oxadiazole-2-thiones has been performed with peracetylated β-pyranosyl bromide in the presence of potassium carbonate. Deprotection of acetylated thioglycosides was necessary for increasing their antibacterial effects. The structures of nucleosides were confirmed by 1H NMR, 13C NMR and HRMS. The anomeric protons of nucleosides c1–4 were assigned to the doublet, confirming the β-configuration. The synthesized compounds were tested for their antimicrobial activity against Acinetobacter calcoaceticus (Gram-negetive) strain in-vitro in comparison with Ampicillin as a reference drug which is normally used for treating such infections. The synthetic compounds showed different inhibition zones against tested bacterial strain. Thioglycoside derivatives of 1,3,4-oxadiazole-2-thiones (c set) were more active against Acinetobacter calcoaceticus ATCC 23055 than “parent” 1,3,4-oxadiazole-2-thiones (a set), confirming the relation between glyco-conjugation and increasing of antiproliferative activity of antibiotic agents. The best result belonged to nucleoside bearing 2-furyl moiety in its heterocyclic nucleus (c4). The existence of m-PhNO2 group as Ar in structures of a set and their corresponding sugar derivatives decreased the antibacterial activity of them in comparison with the rest of synthetic compounds. PMID:28243273

  3. Postcataract surgery endophthalmitis caused by acinetobacter lwoffii.

    PubMed

    Roy, Rupak; Das, Debmalya; Kumar, Saurabh; Mukherjee, Anjan

    2015-01-01

    Acinetobacter lwoffii is a rare cause of endophthalmitis. We report a case of acute postoperative endophthalmitis in a female, who was treated successfully with pars plana vitrectomy and intravitreal antibiotics.

  4. Hemolytic uremic syndrome associated with Acinetobacter hemolyticus.

    PubMed

    da Silva, Paulo Sérgio Lucas; Lipinski, Rubens Wolfe

    2014-08-01

    Shiga toxin-producing Escherichia coli and Shigella dysenteriae have been associated with bloody diarrhea and hemolytic uremic syndrome (HUS) in humans. However, there have been only a couple of reports describing bloody diarrhea associated with Acinetobacter spp. and there are no reports of these bacteria causing HUS in children. Here, we report the case of a nine-month-old boy with bloody diarrhea who developed non-oliguric renal failure. The clinical and laboratory findings supported the diagnosis of Acinetobacter hemolyticus infection associated with HUS. The patient responded favorably to antibiotic therapy plus conservative treatment. In conclusion, Acinetobacter infection should be considered as a plausible cause of HUS in cases where E. coli infection is not involved. The rapid transformation ability of Acinetobacter is a matter of concern.

  5. Effect of chlorine exposure on the survival and antibiotic gene expression of multidrug resistant Acinetobacter baumannii in water.

    PubMed

    Karumathil, Deepti Prasad; Yin, Hsin-Bai; Kollanoor-Johny, Anup; Venkitanarayanan, Kumar

    2014-02-07

    Acinetobacter baumannii is a multidrug resistant pathogen capable of causing a wide spectrum of clinical conditions in humans. Acinetobacter spp. is ubiquitously found in different water sources. Chlorine being the most commonly used disinfectant in water, the study investigated the effect of chlorine on the survival of A. baumannii in water and transcription of genes conferring antibiotic resistance. Eight clinical isolates of A. baumannii, including a fatal meningitis isolate (ATCC 17978) (~108 CFU/mL) were separately exposed to free chlorine concentrations (0.2, 1, 2, 3 and 4 ppm) with a contact time of 30, 60, 90 and 120 second. The surviving pathogen counts at each specified contact time were determined using broth dilution assay. In addition, real-time quantitative PCR (RT-qPCR) analysis of the antibiotic resistance genes (efflux pump genes and those encoding resistance to specific antibiotics) of three selected A. baumannii strains following exposure to chlorine was performed. Results revealed that all eight A. baumannii isolates survived the tested chlorine levels during all exposure times (p > 0.05). Additionally, there was an up-regulation of all or some of the antibiotic resistance genes in A. baumannii, indicating a chlorine-associated induction of antibiotic resistance in the pathogen.

  6. Effect of Chlorine Exposure on the Survival and Antibiotic Gene Expression of Multidrug Resistant Acinetobacter baumannii in Water

    PubMed Central

    Karumathil, Deepti Prasad; Yin, Hsin-Bai; Kollanoor-Johny, Anup; Venkitanarayanan, Kumar

    2014-01-01

    Acinetobacter baumannii is a multidrug resistant pathogen capable of causing a wide spectrum of clinical conditions in humans. Acinetobacter spp. is ubiquitously found in different water sources. Chlorine being the most commonly used disinfectant in water, the study investigated the effect of chlorine on the survival of A. baumannii in water and transcription of genes conferring antibiotic resistance. Eight clinical isolates of A. baumannii, including a fatal meningitis isolate (ATCC 17978) (~108 CFU/mL) were separately exposed to free chlorine concentrations (0.2, 1, 2, 3 and 4 ppm) with a contact time of 30, 60, 90 and 120 second. The surviving pathogen counts at each specified contact time were determined using broth dilution assay. In addition, real-time quantitative PCR (RT-qPCR) analysis of the antibiotic resistance genes (efflux pump genes and those encoding resistance to specific antibiotics) of three selected A. baumannii strains following exposure to chlorine was performed. Results revealed that all eight A. baumannii isolates survived the tested chlorine levels during all exposure times (p > 0.05). Additionally, there was an up-regulation of all or some of the antibiotic resistance genes in A. baumannii, indicating a chlorine-associated induction of antibiotic resistance in the pathogen. PMID:24514427

  7. Ecology, adaptation, and function of methane-sulfidic spring water biofilm microorganisms, including a strain of anaerobic fungus Mucor hiemalis.

    PubMed

    Hoque, Enamul; Fritscher, Johannes

    2017-08-01

    Ecological aspects, adaptation, and some functions of a special biofilm and its unique key anaerobic fungus Mucor hiemalis strain EH11 isolated from a pristine spring (Künzing, Bavaria, Germany) are described. The spring's pure nature is characterized by, for example, bubbling methane, marine-salinity, mild hydrothermal (~19.1°C), sulfidic, and reductive-anoxic (Eh : -241 to -253 mV, O2 : ≤ 0.1 mg/L) conditions. It is geoecologically located at the border zone between Bavarian Forest (crystalline rocky mountains) and the moor-like Danube River valley, where geological displacements bring the spring's water from the deeper layers of former marine sources up to the surface. In the spring's outflow, a special biofilm with selective microorganisms consisting of archaea, bacteria, protozoa (ciliate), and fungus was found. Typical sulfidic-spring bryophyta and macrozoobenthos were missing, but many halo- and anaerotolerant diatoms and ciliate Vorticella microstoma beside EH11 were identified. Phase contrast and scanning electron microscopy revealed the existence of a stabilizing matrix in the biofilm formed by the sessile fungal hyphae and the exopolysaccharide substance (EPS) structures, which harbors other microorganisms. In response to ecological adaptation pressure caused by methane bubbles, EH11 developed an atypical spring-like hyphal morphology, similar to the spiral stalk of ciliate V. microstoma, to rise up with methane bubbles. For the first time, it was also demonstrated that under strict anaerobic conditions EH11 changes its asexual reproduction process by forming pseudosporangia via hyphal cell divisions as well as switching its metabolism to chemoautotrophic bacteria-like anaerobic life using acetate as an e-donor and ferrihydrite as an e-acceptor, all without fermentation. EH11 can be suggested to be useful for the microbial community in the Künzing biofilm not only due to its physical stabilization of the biofilm's matrix but also due to its

  8. Copper Resistance of the Emerging Pathogen Acinetobacter baumannii

    PubMed Central

    Williams, Caitlin L.; Neu, Heather M.; Gilbreath, Jeremy J.; Michel, Sarah L. J.; Zurawski, Daniel V.

    2016-01-01

    ABSTRACT Acinetobacter baumannii is an important emerging pathogen that is capable of causing many types of severe infection, especially in immunocompromised hosts. Since A. baumannii can rapidly acquire antibiotic resistance genes, many infections are on the verge of being untreatable, and novel therapies are desperately needed. To investigate the potential utility of copper-based antibacterial strategies against Acinetobacter infections, we characterized copper resistance in a panel of recent clinical A. baumannii isolates. Exposure to increasing concentrations of copper in liquid culture and on solid surfaces resulted in dose-dependent and strain-dependent effects; levels of copper resistance varied broadly across isolates, possibly resulting from identified genotypic variation among strains. Examination of the growth-phase-dependent effect of copper on A. baumannii revealed that resistance to copper increased dramatically in stationary phase. Moreover, A. baumannii biofilms were more resistant to copper than planktonic cells but were still susceptible to copper toxicity. Exposure of bacteria to subinhibitory concentrations of copper allowed them to better adapt to and grow in high concentrations of copper; this copper tolerance response is likely achieved via increased expression of copper resistance mechanisms. Indeed, genomic analysis revealed numerous putative copper resistance proteins that share amino acid homology to known proteins in Escherichia coli and Pseudomonas aeruginosa. Transcriptional analysis revealed significant upregulation of these putative copper resistance genes following brief copper exposure. Future characterization of copper resistance mechanisms may aid in the search for novel antibiotics against Acinetobacter and other highly antibiotic-resistant pathogens. IMPORTANCE Acinetobacter baumannii causes many types of severe nosocomial infections; unfortunately, some isolates have acquired resistance to almost every available antibiotic

  9. Prevalence of digestive tract colonization of carbapenem-resistant Acinetobacter baumannii in hospitals in Saudi Arabia.

    PubMed

    Aljindan, Reem; Bukharie, Huda; Alomar, Amer; Abdalhamid, Baha

    2015-04-01

    Carbapenem-resistant Acinetobacter baumannii is a major health problem worldwide, especially in intensive care units (ICUs). This study aimed to detect the prevalence of A. baumannii colonization of the gastrointestinal tract of patients admitted to the ICU in two hospitals in Saudi Arabia. In addition, it aimed to characterize the molecular mechanisms of carbapenem resistance in these isolates. From January to June 2014, 565 rectal swab specimens were screened for Acinetobacer strains and carbapenem resistance using CHROMagar Acinetobacter and CHROMagar KPC agar plates, respectively. Organism identification and susceptibility were detected using the Vitek 2 system. A total of 47 Acinetobacter spp. were detected, and 35 were resistant to carbapenem, making the prevalence of Acinetobacter spp. 8.3% (47/565) and carbapenem resistance (6.2%, 35/565). The 47 strains showed remarkable clonal diversity as revealed by PFGE. Using PCR, OXA-51, a chromosomal marker for A. baumannii, was detected in 46 strains. OXA-23 β-lactamase was detected in all 35 carbapenem-resistant A. baumannii. No IMP, VIM, SPM, SIM, GIM, KPC or NDM β-lactamases were detected in these isolates. Thus, OXA-23 was the main mechanism of carbapenem resistance in these isolates. To the best of our knowledge, this is the first study to detect the prevalence of Acinetobacter colonization in the digestive tract of ICU patients in Saudi Arabia. This study revealed the importance of having well-established protocols for early identification of these multidrug-resistant organisms, optimizing infection-control strategies and having active surveillance studies to reduce morbidity, mortality and cost.

  10. The structure of alanine racemase from Acinetobacter baumannii.

    PubMed

    Davis, Emily; Scaletti-Hutchinson, Emma; Opel-Reading, Helen; Nakatani, Yoshio; Krause, Kurt L

    2014-09-01

    Acinetobacter baumannii is an opportunistic Gram-negative bacterium which is a common cause of hospital-acquired infections. Numerous antibiotic-resistant strains exist, emphasizing the need for the development of new antimicrobials. Alanine racemase (Alr) is a pyridoxal 5'-phosphate dependent enzyme that is responsible for racemization between enantiomers of alanine. As D-alanine is an essential component of the bacterial cell wall, its inhibition is lethal to prokaryotes, making it an excellent antibiotic drug target. The crystal structure of A. baumannii alanine racemase (AlrAba) from the highly antibiotic-resistant NCTC13302 strain has been solved to 1.9 Å resolution. Comparison of AlrAba with alanine racemases from closely related bacteria demonstrates a conserved overall fold. The substrate entryway and active site of the enzymes were shown to be highly conserved. The structure of AlrAba will provide the template required for future structure-based drug-design studies.

  11. Susceptibility of Aedes albopictus and Aedes aegypti to three imported Chikungunya virus strains, including the E1/226V variant in Taiwan.

    PubMed

    Chen, Tien-Huang; Jian, Shu-Wan; Wang, Chih-Yuan; Lin, Cheo; Wang, Pei-Feng; Su, Chien-Ling; Teng, Hwa-Jen; Shu, Pei-Yun; Wu, Ho-Sheng

    2015-06-01

    An E1/226V variant Chikungunya virus (CHIKV) efficiently transmitted by Aedes albopictus to humans poses a significant threat to public health for those areas with the presence of Aedes albopictus, including Taiwan. We infected three imported CHIKV isolates including the E1/226V variant with Ae. albopictus and Aedes aegypti in the laboratory to understand the disease risk. Viral RNA was measured by real time reverse transcription polymerase chain reaction. The viral susceptibility varied by virus strain and mosquito species and strain. The Asian virus strain started to replicate at 5-6 days post infection (dpi) with the maximum virus yield, ranging from 10(3.63) to 10(3.87) at 5-10 dpi in both species. The variant CHIKV Central/East/South African (CESA) virus genotype replicated earlier at 1 dpi with the maximum virus yield ranging from 10(5.63) to 10(6.52) at 3-6 dpi in Ae. albopictus females while the nonvariant virus strain replicated at 1-2 dpi with the maximum virus yield ranging from 10(5.51) to 10(6.27) at 6-12 dpi. In Ae. aegypti, these viruses replicated at 1-2 dpi, with maximum yields at 4-5 dpi (range from 10(5.38) to 10(5.62)). We concluded that the risk of CHIKV in Taiwan is high in all distribution areas of Ae. aegypti and Ae. albopictus for the CESA genotype and that the E1/226V variant virus strain presents an even higher risk. Copyright © 2015. Published by Elsevier B.V.

  12. Strains

    MedlinePlus

    Pulled muscle ... can include: Pain and difficulty moving the injured muscle Discolored and bruised skin Swelling ... if you still have pain. Rest the pulled muscle for at least a day. If possible, keep ...

  13. [Current approaches to explain the virulence of Acinetobacter baumannii].

    PubMed

    Aşık, Gülşah

    2011-04-01

    Acinetobacter baumannii which is one of the most frequent nosocomial pathogens, has drawn attention in the last years owing to multi-drug resistant strains. A.baumannii may give rise to nosocomial epidemics especially in intensive care units and may lead to treatment failure due to its increasing antimicrobial resistance. These gram-negative non-fermentative coccobacilli may be encountered also in community associated infections. However, they are frequently isolated in pneumonia, urinary tract infection, bacteremia, meningitis and wound infections that develop in patients hospitalized for serious diseases. Although detailed data about the epidemiology and antimicrobial resistance patterns related to this bacteria exist, relatively limited data is present about the virulence factors and environmental physiology of A.baumannii. The role of some bacterial virulence factors in the pathogenesis of Acinetobacter infections have been enlightened by recent investigations. Among these virulence factors, production of extracellular enzymes with lipolytic and cytolytic activities, outer membrane protein (AbOmpA) with apoptotic effects on epithelial cells, adhesion molecules (fimbria and AbOmpA) that function during attachment to epithelial cells, K1 type capsular structure, type-1 pili and AbOmpA induced biofilm formation, siderophore (acinetobactin) or hemin mediated iron acquisition mechanisms, quorum sensing system that functions by the help of N-acyl homoserine lacton signal molecules and cellular components that enable Acinetobacter species to live under inappropriate environmental conditions like dryness, low temperature, restricted nutritional elements, can be counted. New information about the virulence factors will help better understanding of the adaptive response of A.baumannii in the host setting. This review is focused on the current information about the virulence factors of of A.baumannii.

  14. Identification, genotypic relation, and clinical features of colistin-resistant isolates of Acinetobacter genomic species 13BJ/14TU from bloodstreams of patients in a university hospital.

    PubMed

    Lee, Seung Yeob; Shin, Jong Hee; Park, Kyung Hwa; Kim, Ju Hee; Shin, Myung Geun; Suh, Soon Pal; Ryang, Dong Wook; Kim, Soo Hyun

    2014-03-01

    Colistin resistance remains rare among clinical isolates of Acinetobacter species. We noted the emergence of colistin-resistant bloodstream isolates of the Acinetobacter genomic species (GS) 13BJ/14TU from patients at a university hospital between 2003 and 2011. We report here, for the first time, the microbiological and molecular characteristics of these isolates, with clinical features of Acinetobacter GS 13BJ/14TU bacteremia. All 11 available patient isolates were correctly identified as Acinetobacter GS 13BJ/14TU using partial rpoB gene sequencing but were misidentified using the phenotypic methods Vitek 2 (mostly as Acinetobacter baumannii), MicroScan (mostly as A. baumannii/Acinetobacter haemolyticus), and the API 20 NE system (all as A. haemolyticus). Most isolates were susceptible to commonly used antibiotics, including carbapenems, but all were resistant to colistin, for which it is unknown whether the resistance is acquired or intrinsic. However, the fact that none of the patients had a history of colistin therapy strongly suggests that Acinetobacter GS 13BJ/14TU is innately resistant to colistin. The phylogenetic tree of multilocus sequence typing (MLST) showed that all 11 isolates formed a separate cluster from other Acinetobacter species and yielded five sequence types. However, pulsed-field gel electrophoresis (PFGE) revealed 11 distinct patterns, suggesting that the bacteremia had occurred sporadically. Four patients showed persistent bacteremia (6 to 17 days), and all 11 patients had excellent outcomes with cleared bacteremia, suggesting that patients with Acinetobacter GS 13BJ/14TU-associated bacteremia show a favorable outcome. These results emphasize the importance of precise species identification, especially regarding colistin resistance in Acinetobacter species. In addition, MLST offers another approach to the identification of Acinetobacter GS 13BJ/14TU, whereas PFGE is useful for genotyping for this species.

  15. Identification, Genotypic Relation, and Clinical Features of Colistin-Resistant Isolates of Acinetobacter Genomic Species 13BJ/14TU from Bloodstreams of Patients in a University Hospital

    PubMed Central

    Lee, Seung Yeob; Shin, Jong Hee; Park, Kyung Hwa; Kim, Ju Hee; Shin, Myung Geun; Suh, Soon Pal; Ryang, Dong Wook

    2014-01-01

    Colistin resistance remains rare among clinical isolates of Acinetobacter species. We noted the emergence of colistin-resistant bloodstream isolates of the Acinetobacter genomic species (GS) 13BJ/14TU from patients at a university hospital between 2003 and 2011. We report here, for the first time, the microbiological and molecular characteristics of these isolates, with clinical features of Acinetobacter GS 13BJ/14TU bacteremia. All 11 available patient isolates were correctly identified as Acinetobacter GS 13BJ/14TU using partial rpoB gene sequencing but were misidentified using the phenotypic methods Vitek 2 (mostly as Acinetobacter baumannii), MicroScan (mostly as A. baumannii/Acinetobacter haemolyticus), and the API 20 NE system (all as A. haemolyticus). Most isolates were susceptible to commonly used antibiotics, including carbapenems, but all were resistant to colistin, for which it is unknown whether the resistance is acquired or intrinsic. However, the fact that none of the patients had a history of colistin therapy strongly suggests that Acinetobacter GS 13BJ/14TU is innately resistant to colistin. The phylogenetic tree of multilocus sequence typing (MLST) showed that all 11 isolates formed a separate cluster from other Acinetobacter species and yielded five sequence types. However, pulsed-field gel electrophoresis (PFGE) revealed 11 distinct patterns, suggesting that the bacteremia had occurred sporadically. Four patients showed persistent bacteremia (6 to 17 days), and all 11 patients had excellent outcomes with cleared bacteremia, suggesting that patients with Acinetobacter GS 13BJ/14TU-associated bacteremia show a favorable outcome. These results emphasize the importance of precise species identification, especially regarding colistin resistance in Acinetobacter species. In addition, MLST offers another approach to the identification of Acinetobacter GS 13BJ/14TU, whereas PFGE is useful for genotyping for this species. PMID:24403305

  16. In Vitro Efficacy of Doripenem against Pseudomonas aeruginosa and Acinetobacter baumannii by E-Test.

    PubMed

    Gilani, Mehreen; Munir, Tehmina; Latif, Mahwish; Rehman, Sabahat; Ansari, Maliha; Hafeez, Amira; Najeeb, Sara; Saad, Nadia; Gilani, Mehwish

    2015-10-01

    To assess the in vitro efficacy of doripenem against Pseudomonas aeruginosa and Acinetobacter baumannii using Epsilometer strips. Cross-sectional study. Department of Microbiology, Army Medical College, Rawalpindi and National University of Sciences and Technology, Islamabad, from May 2014 to September 2014. A total of 60 isolates of Acinetobacter baumannii and Pseudomonas aeruginosa collected from various clinical samples received from Military Hospital were included in the study. The specimens were inoculated onto blood, MacConkey and chocolate agars. The isolates were identified using Gram staining, motility, catalase test, oxidase test and API 20NE (Biomeriux, France). Organisms identified as Acinetobacter baumannii and Pseudomonas aeruginosa were included in the study. Bacterial suspensions equivalent to 0.5 McFarland turbidity standard of the isolates were prepared and applied on Mueller Hinton agar. Epsilometer strip was placed in the center of the plate and incubated for 18-24 hours. Minimum Inhibitory Concentration (MIC) was taken to be the point where the epsilon intersected the E-strip. MIC of all the isolates was noted. For Pseudomonas aeruginosa isolates, MIC(50) was 12 µg/mL and MIC(90) was 32 µg/mL. For Acinetobacter baumannii MIC(50) and MIC(90) was 32 µg/mL. Doripenem is no more effective against Pseudomonas aeruginosa and Acinetobacter baumannii in our setting.

  17. Towards the complete proteinaceous regulome of Acinetobacter baumannii

    PubMed Central

    Pérez-Rueda, Ernesto; Antonio Ibarra, J

    2017-01-01

    The emergence of Acinetobacter baumannii strains, with broad multidrug-resistance phenotypes and novel virulence factors unique to hypervirulent strains, presents a major threat to human health worldwide. Although a number of studies have described virulence-affecting entities for this organism, very few have identified regulatory elements controlling their expression. Previously, our group has documented the global identification and curation of regulatory RNAs in A. baumannii. As such, in the present study, we detail an extension of this work, the performance of an extensive bioinformatic analysis to identify regulatory proteins in the recently annotated genome of the highly virulent AB5075 strain. In so doing, 243 transcription factors, 14 two-component systems (TCSs), 2 orphan response regulators, 1 hybrid TCS and 5 σ factors were found. A comparison of these elements between AB5075 and other clinical isolates, as well as a laboratory strain, led to the identification of several conserved regulatory elements, whilst at the same time uncovering regulators unique to hypervirulent strains. Lastly, by comparing regulatory elements compiled in this study to genes shown to be essential for AB5075 infection, we were able to highlight elements with a specific importance for pathogenic behaviour. Collectively, our work offers a unique insight into the regulatory network of A. baumannii strains, and provides insight into the evolution of hypervirulent lineages. PMID:28663824

  18. Towards the complete proteinaceous regulome of Acinetobacter baumannii.

    PubMed

    Casella, Leila G; Weiss, Andy; Pérez-Rueda, Ernesto; Antonio Ibarra, J; Shaw, Lindsey N

    2017-03-01

    The emergence of Acinetobacter baumannii strains, with broad multidrug-resistance phenotypes and novel virulence factors unique to hypervirulent strains, presents a major threat to human health worldwide. Although a number of studies have described virulence-affecting entities for this organism, very few have identified regulatory elements controlling their expression. Previously, our group has documented the global identification and curation of regulatory RNAs in A. baumannii. As such, in the present study, we detail an extension of this work, the performance of an extensive bioinformatic analysis to identify regulatory proteins in the recently annotated genome of the highly virulent AB5075 strain. In so doing, 243 transcription factors, 14 two-component systems (TCSs), 2 orphan response regulators, 1 hybrid TCS and 5 σ factors were found. A comparison of these elements between AB5075 and other clinical isolates, as well as a laboratory strain, led to the identification of several conserved regulatory elements, whilst at the same time uncovering regulators unique to hypervirulent strains. Lastly, by comparing regulatory elements compiled in this study to genes shown to be essential for AB5075 infection, we were able to highlight elements with a specific importance for pathogenic behaviour. Collectively, our work offers a unique insight into the regulatory network of A. baumannii strains, and provides insight into the evolution of hypervirulent lineages.

  19. Role of Acinetobacter baumannii UmuD homologs in antibiotic resistance acquired through DNA damage-induced mutagenesis.

    PubMed

    Aranda, Jesús; López, Mario; Leiva, Enoy; Magán, Andrés; Adler, Ben; Bou, Germán; Barbé, Jordi

    2014-01-01

    The role of Acinetobacter baumannii ATCC 17978 UmuDC homologs A1S_0636-A1S_0637, A1S_1174-A1S_1173, and A1S_1389 (UmuDAb) in antibiotic resistance acquired through UV-induced mutagenesis was evaluated. Neither the growth rate nor the UV-related survival of any of the three mutants was significantly different from that of the wild-type parental strain. However, all mutants, and especially the umuDAb mutant, were less able to acquire resistance to rifampin and streptomycin through the activities of their error-prone DNA polymerases. Furthermore, in the A. baumannii mutant defective in the umuDAb gene, the spectrum of mutations included a dramatic reduction in the frequency of transition mutations, the mutagenic signature of the DNA polymerase V encoded by umuDC.

  20. Galleria mellonella as a model system to study Acinetobacter baumannii pathogenesis and therapeutics.

    PubMed

    Peleg, Anton Y; Jara, Sebastian; Monga, Divya; Eliopoulos, George M; Moellering, Robert C; Mylonakis, Eleftherios

    2009-06-01

    Nonmammalian model systems of infection such as Galleria mellonella (caterpillars of the greater wax moth) have significant logistical and ethical advantages over mammalian models. In this study, we utilize G. mellonella caterpillars to study host-pathogen interactions with the gram-negative organism Acinetobacter baumannii and determine the utility of this infection model to study antibacterial efficacy. After infecting G. mellonella caterpillars with a reference A. baumannii strain, we observed that the rate of G. mellonella killing was dependent on the infection inoculum and the incubation temperature postinfection, with greater killing at 37 degrees C than at 30 degrees C (P = 0.01). A. baumannii strains caused greater killing than the less-pathogenic species Acinetobacter baylyi and Acinetobacter lwoffii (P < 0.001). Community-acquired A. baumannii caused greater killing than a reference hospital-acquired strain (P < 0.01). Reduced levels of production of the quorum-sensing molecule 3-hydroxy-C(12)-homoserine lactone caused no change in A. baumannii virulence against G. mellonella. Treatment of a lethal A. baumannii infection with antibiotics that had in vitro activity against the infecting A. baumannii strain significantly prolonged the survival of G. mellonella caterpillars compared with treatment with antibiotics to which the bacteria were resistant. G. mellonella is a relatively simple, nonmammalian model system that can be used to facilitate the in vivo study of host-pathogen interactions in A. baumannii and the efficacy of antibacterial agents.

  1. Strains of Sarcocystis neurona exhibit differences in their surface antigens, including the absence of the major surface antigen SnSAG1.

    PubMed

    Howe, Daniel K; Gaji, Rajshekhar Y; Marsh, Antoinette E; Patil, Bhagyashree A; Saville, William J; Lindsay, David S; Dubey, J P; Granstrom, David E

    2008-05-01

    A gene family of surface antigens is expressed by merozoites of Sarcocystis neurona, the primary cause of equine protozoal myeloencephalitis (EPM). These surface proteins, designated SnSAGs, are immunodominant and therefore excellent candidates for development of EPM diagnostics or vaccines. Prior work had identified an EPM isolate lacking the major surface antigen SnSAG1, thus suggesting there may be some diversity in the SnSAGs expressed by different S. neurona isolates. Therefore, a bioinformatic, molecular and immunological study was conducted to assess conservation of the SnSAGs. Examination of an expressed sequence tag (EST) database revealed several notable SnSAG polymorphisms. In particular, the EST information implied that the EPM strain SN4 lacked the major surface antigen SnSAG1. The absence of this surface antigen from the SN4 strain was confirmed by both Western blot and Southern blot. To evaluate SnSAG polymorphisms in the S. neurona population, 14 strains were examined by Western blots using monospecific polyclonal antibodies against the four described SnSAGs. The results of these analyses demonstrated that SnSAG2, SnSAG3, and SnSAG4 are present in all 14 S. neurona strains tested, although some variance in SnSAG4 was observed. Importantly, SnSAG1 was not detected in seven of the strains, which included isolates from four cases of EPM and a case of fatal meningoencephalitis in a sea otter. Genetic analyses by PCR using gene-specific primers confirmed the absence of the SnSAG1 locus in six of these seven strains. Collectively, the data indicated that there is heterogeneity in the surface antigen composition of different S. neurona isolates, which is an important consideration for development of serological tests and prospective vaccines for EPM. Furthermore, the diversity reported herein likely extends to other phenotypes, such as strain virulence, and may have implications for the phylogeny of the various Sarcocystis spp. that undergo sexual stages

  2. Selectable Markers for Use in Genetic Manipulation of Extensively Drug-Resistant (XDR) Acinetobacter baumannii HUMC1

    PubMed Central

    Ulhaq, Amber; Yan, Jun; Pantapalangkoor, Paul; Nielsen, Travis B.; Davies, Bryan W.; Actis, Luis A.; Spellberg, Brad

    2017-01-01

    ABSTRACT Acinetobacter baumannii is one of the most antibiotic-resistant pathogens in clinical medicine, and extensively drug-resistant (XDR) strains are commonly isolated from infected patients. Such XDR strains are already resistant to traditional selectable genetic markers, limiting the ability to conduct pathogenesis research by genetic disruption. Optimization of selectable markers is therefore critical for the advancement of fundamental molecular biology techniques to use in these strains. We screened 23 drugs that constitute a broad array of antibiotics spanning multiple drug classes against HUMC1, a highly virulent and XDR A. baumannii clinical blood and lung isolate. HUMC1 is resistant to all clinically useful antibiotics that are reported by the clinical microbiology laboratory, except for colistin. Ethical concerns about intentionally establishing pan-resistance, including to the last-line agent, colistin, in a clinical isolate made identification of other markers desirable. We screened additional antibiotics that are in clinical use and those that are useful only in a lab setting to identify selectable markers that were effective at selecting for transformants in vitro. We show that supraphysiological levels of tetracycline can overcome innate drug resistance displayed by this XDR strain. Last, we demonstrate that transformation of the tetA (tetracycline resistance) and Sh ble (zeocin resistance), but not pac (puromycin resistance), resistance cassettes allow for selection of drug-resistant transformants. These results make the genetic manipulation of XDR A. baumannii strains easily achieved. IMPORTANCE Multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR) strains of Acinetobacter baumannii have frequently been characterized. The ability of A. baumannii to develop resistance to antibiotics is a key reason this organism has been difficult to study using genetic and molecular biology approaches. Here we report

  3. Selectable Markers for Use in Genetic Manipulation of Extensively Drug-Resistant (XDR) Acinetobacter baumannii HUMC1.

    PubMed

    Luna, Brian M; Ulhaq, Amber; Yan, Jun; Pantapalangkoor, Paul; Nielsen, Travis B; Davies, Bryan W; Actis, Luis A; Spellberg, Brad

    2017-01-01

    Acinetobacter baumannii is one of the most antibiotic-resistant pathogens in clinical medicine, and extensively drug-resistant (XDR) strains are commonly isolated from infected patients. Such XDR strains are already resistant to traditional selectable genetic markers, limiting the ability to conduct pathogenesis research by genetic disruption. Optimization of selectable markers is therefore critical for the advancement of fundamental molecular biology techniques to use in these strains. We screened 23 drugs that constitute a broad array of antibiotics spanning multiple drug classes against HUMC1, a highly virulent and XDR A. baumannii clinical blood and lung isolate. HUMC1 is resistant to all clinically useful antibiotics that are reported by the clinical microbiology laboratory, except for colistin. Ethical concerns about intentionally establishing pan-resistance, including to the last-line agent, colistin, in a clinical isolate made identification of other markers desirable. We screened additional antibiotics that are in clinical use and those that are useful only in a lab setting to identify selectable markers that were effective at selecting for transformants in vitro. We show that supraphysiological levels of tetracycline can overcome innate drug resistance displayed by this XDR strain. Last, we demonstrate that transformation of the tetA (tetracycline resistance) and Sh ble (zeocin resistance), but not pac (puromycin resistance), resistance cassettes allow for selection of drug-resistant transformants. These results make the genetic manipulation of XDR A. baumannii strains easily achieved. IMPORTANCE Multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR) strains of Acinetobacter baumannii have frequently been characterized. The ability of A. baumannii to develop resistance to antibiotics is a key reason this organism has been difficult to study using genetic and molecular biology approaches. Here we report selectable

  4. Characterization and Testing the Efficiency of Acinetobacter baumannii Phage vB-GEC_Ab-M-G7 as an Antibacterial Agent

    PubMed Central

    Kusradze, Ia; Karumidze, Natia; Rigvava, Sophio; Dvalidze, Teona; Katsitadze, Malkhaz; Amiranashvili, Irakli; Goderdzishvili, Marina

    2016-01-01

    Acinetobacter baumannii is a gram-negative, non-motile bacterium that, due to its multidrug resistance, has become a major nosocomial pathogen. The increasing number of multidrug resistant (MDR) strains has renewed interest in phage therapy. The aim of our study was to assess the effectiveness of phage administration in Acinetobacter baumannii wound infections in an animal model to demonstrate phage therapy as non-toxic, safe and alternative antibacterial remedy. Using classical methods for the study of bacteriophage properties, we characterized phage vB-GEC_Ab-M-G7 as a dsDNA myovirus with a 90 kb genome size. Important characteristics of vB-GEC_Ab-M-G7include a short latent period and large burst size, wide host range, resistance to chloroform and thermal and pH stability. In a rat wound model, phage application effectively decreased the number of bacteria isolated from the wounds of successfully treated animals. This study highlights the effectiveness of the phage therapy and provides further insight into treating infections caused by MDR strains using phage administration. PMID:27757110

  5. Acinetobacter seifertii Isolated from China: Genomic Sequence and Molecular Epidemiology Analyses.

    PubMed

    Yang, Yunxing; Wang, Jianfeng; Fu, Ying; Ruan, Zhi; Yu, Yunsong

    2016-03-01

    Clinical infections caused by Acinetobacter spp. have increasing public health concerns because of their global occurrence and ability to acquire multidrug resistance. Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex encompasses A. calcoaceticus, A. baumannii, A. pittii (formerly genomic species 3), and A nosocomial (formerly genomic species 13TU), which are predominantly responsible for clinical pathogenesis in the Acinetobacter genus. In our previous study, a putative novel species isolated from 385 non-A. baumannii spp. strains based on the rpoB gene phylogenetic tree was reported. Here, the putative novel species was identified as A. seifertii based on the whole-genome phylogenetic tree. A. seifertii was recognized as a novel member of the ACB complex and close to A. baumannii and A. nosocomials. Furthermore, we studied the characteristics of 10 A. seifertii isolates, which were distributed widely in 6 provinces in China and mainly caused infections in the elderly or children. To define the taxonomic status and characteristics, the biochemical reactions, antimicrobial susceptibility testing, pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and whole-genome sequence analysis were performed. The phenotypic characteristics failed to distinguish A. serfertii from other species in the ACB complex. Most of the A. seifertii isolates were susceptible to antibiotics commonly used for nosocomial Acinetobacter spp. infections, but one isolate (strain A362) was resistant to ampicillin/sulbactam, ceftazidime and amikacin. The different patterns of MLST and PFGE suggested that the 10 isolates were not identical and lacked clonal relatedness. Our study reported for the first time the molecular epidemiological and genomic features of widely disseminated A. seifertii in China. These observations could enrich the knowledge of infections caused by non-A. baumannii and may provide a scientific basis for future clinical treatment.

  6. A penicillin-binding protein inhibits selection of colistin-resistant, lipooligosaccharide-deficient Acinetobacter baumannii

    PubMed Central

    Boll, Joseph M.; Crofts, Alexander A.; Peters, Katharina; Cattoir, Vincent; Vollmer, Waldemar; Davies, Bryan W.; Trent, M. Stephen

    2016-01-01

    The Gram-negative bacterial outer membrane fortifies the cell against environmental toxins including antibiotics. Unique glycolipids called lipopolysaccharide/lipooligosaccharide (LPS/LOS) are enriched in the cell-surface monolayer of the outer membrane and promote antimicrobial resistance. Colistin, which targets the lipid A domain of LPS/LOS to lyse the cell, is the last-line treatment for multidrug-resistant Gram-negative infections. Lipid A is essential for the survival of most Gram-negative bacteria, but colistin-resistant Acinetobacter baumannii lacking lipid A were isolated after colistin exposure. Previously, strain ATCC 19606 was the only A. baumannii strain demonstrated to subsist without lipid A. Here, we show that other A. baumannii strains can also survive without lipid A, but some cannot, affording a unique model to study endotoxin essentiality. We assessed the capacity of 15 clinical A. baumannii isolates including 9 recent clinical isolates to develop colistin resistance through inactivation of the lipid A biosynthetic pathway, the products of which assemble the LOS precursor. Our investigation determined that expression of the well-conserved penicillin-binding protein (PBP) 1A, prevented LOS-deficient colony isolation. The glycosyltransferase activity of PBP1A, which aids in the polymerization of the peptidoglycan cell wall, was lethal to LOS-deficient A. baumannii. Global transcriptomic analysis of a PBP1A-deficient mutant and four LOS-deficient A. baumannii strains showed a concomitant increase in transcription of lipoproteins and their transporters. Examination of the LOS-deficient A. baumannii cell surface demonstrated that specific lipoproteins were overexpressed and decorated the cell surface, potentially compensating for LOS removal. This work expands our knowledge of lipid A essentiality and elucidates a drug resistance mechanism. PMID:27681618

  7. The Complete Genome and Phenome of a Community-Acquired Acinetobacter baumannii

    PubMed Central

    Farrugia, Daniel N.; Elbourne, Liam D. H.; Hassan, Karl A.; Eijkelkamp, Bart A.; Tetu, Sasha G.; Brown, Melissa H.; Shah, Bhumika S.; Peleg, Anton Y.; Mabbutt, Bridget C.; Paulsen, Ian T.

    2013-01-01

    Many sequenced strains of Acinetobacter baumannii are established nosocomial pathogens capable of resistance to multiple antimicrobials. Community-acquired A. baumannii in contrast, comprise a minor proportion of all A. baumannii infections and are highly susceptible to antimicrobial treatment. However, these infections also present acute clinical manifestations associated with high reported rates of mortality. We report the complete 3.70 Mbp genome of A. baumannii D1279779, previously isolated from the bacteraemic infection of an Indigenous Australian; this strain represents the first community-acquired A. baumannii to be sequenced. Comparative analysis of currently published A. baumannii genomes identified twenty-four accessory gene clusters present in D1279779. These accessory elements were predicted to encode a range of functions including polysaccharide biosynthesis, type I DNA restriction-modification, and the metabolism of novel carbonaceous and nitrogenous compounds. Conversely, twenty genomic regions present in previously sequenced A. baumannii strains were absent in D1279779, including gene clusters involved in the catabolism of 4-hydroxybenzoate and glucarate, and the A. baumannii antibiotic resistance island, known to bestow resistance to multiple antimicrobials in nosocomial strains. Phenomic analysis utilising the Biolog Phenotype Microarray system indicated that A. baumannii D1279779 can utilise a broader range of carbon and nitrogen sources than international clone I and clone II nosocomial isolates. However, D1279779 was more sensitive to antimicrobial compounds, particularly beta-lactams, tetracyclines and sulphonamides. The combined genomic and phenomic analyses have provided insight into the features distinguishing A. baumannii isolated from community-acquired and nosocomial infections. PMID:23527001

  8. Resistance patterns of multidrug resistant Acinetobacter baumannii in an ICU of a tertiary care hospital, Malaysia.

    PubMed

    Janahiraman, Sivakami; Aziz, Muhammad Nazri; Hoo, Fan Kee; P'ng, Hon Shen; Boo, Yang Liang; Ramachandran, Vasudevan; Shamsuddin, Ahmad Fuad

    2015-01-01

    Antimicrobial resistance is a major health problem worldwide in hospitals. The main contributing factors are exposures to broad-spectrum antimicrobials and cross-infections. Understanding the extent and type of antimicrobial use in tertiary care hospitals will aid in developing national antimicrobial stewardship priorities. In this study, we have analyzed the antimicrobial agents' usage for acquisition of multidrug resistant using retrospective, cross-sectional, single-centre study in a multidisciplinary ICU at tertiary care hospital. Acinetobacter baumannii (ACB) was isolated in various specimens from 662 patients. From these, 136 patients who were diagnosed with Ventilator-associated pneumonia (VAP) caused by ACB were included into the study. In our study, MDR strain accounts for 51% of all VAP cases caused by ACB. The development of ACB VAP were 10.5 + 6.4 days for MDR strains compared to susceptible organism (7.8 + 4.5 days) and had significantly longer ICU stay. The study concludes that prudent use of antimicrobial agents is important to reduce acquisition of MDR ACB.

  9. Identification of NDM-1 in a Putatively Novel Acinetobacter Species ("NB14") Closely Related to Acinetobacter pittii.

    PubMed

    Espinal, Paula; Mosqueda, Noraida; Telli, Murat; van der Reijden, Tanny; Rolo, Dora; Fernández-Orth, Dietmar; Dijkshoorn, Lenie; Roca, Ignasi; Vila, Jordi

    2015-10-01

    In this study, we describe the molecular characterization of a plasmid-located blaNDM-1 harbored by an Acinetobacter clinical isolate recovered from a patient in Turkey that putatively constitutes a novel Acinetobacter species, as shown by its distinct ARDRA (amplified 16S ribosomal DNA restriction analysis) profile and molecular sequencing techniques. blaNDM-1 was carried by a conjugative plasmid widespread among non-baumannii Acinetobacter isolates, suggesting its potential for dissemination before reaching more clinically relevant Acinetobacter species.

  10. Global Transcriptome and Physiological Responses of Acinetobacter oleivorans DR1 Exposed to Distinct Classes of Antibiotics

    PubMed Central

    Heo, Aram; Jang, Hyun-Jin; Sung, Jung-Suk; Park, Woojun

    2014-01-01

    The effects of antibiotics on environment-originated nonpathogenic Acinetobacter species have been poorly explored. To understand the antibiotic-resistance mechanisms that function in nonpathogenic Acinetobacter species, we used an RNA-sequencing (RNA-seq) technique to perform global gene-expression profiling of soil-borne Acinetobacter oleivorans DR1 after exposing the bacteria to 4 classes of antibiotics (ampicillin, Amp; kanamycin, Km; tetracycline, Tc; norfloxacin, Nor). Interestingly, the well-known two global regulators, the soxR and the rpoE genes are present among 41 commonly upregulated genes under all 4 antibiotic-treatment conditions. We speculate that these common genes are essential for antibiotic resistance in DR1. Treatment with the 4 antibiotics produced diverse physiological and phenotypic changes. Km treatment induced the most dramatic phenotypic changes. Examination of mutation frequency and DNA-repair capability demonstrated the induction of the SOS response in Acinetobacter especially under Nor treatment. Based on the RNA-seq analysis, the glyoxylate-bypass genes of the citrate cycle were specifically upregulated under Amp treatment. We also identified newly recognized non-coding small RNAs of the DR1 strain, which were also confirmed by Northern blot analysis. These results reveal that treatment with antibiotics of distinct classes differentially affected the gene expression and physiology of DR1 cells. This study expands our understanding of the molecular mechanisms of antibiotic-stress response of environment-originated bacteria and provides a basis for future investigations. PMID:25330344

  11. Global transcriptome and physiological responses of Acinetobacter oleivorans DR1 exposed to distinct classes of antibiotics.

    PubMed

    Heo, Aram; Jang, Hyun-Jin; Sung, Jung-Suk; Park, Woojun

    2014-01-01

    The effects of antibiotics on environment-originated nonpathogenic Acinetobacter species have been poorly explored. To understand the antibiotic-resistance mechanisms that function in nonpathogenic Acinetobacter species, we used an RNA-sequencing (RNA-seq) technique to perform global gene-expression profiling of soil-borne Acinetobacter oleivorans DR1 after exposing the bacteria to 4 classes of antibiotics (ampicillin, Amp; kanamycin, Km; tetracycline, Tc; norfloxacin, Nor). Interestingly, the well-known two global regulators, the soxR and the rpoE genes are present among 41 commonly upregulated genes under all 4 antibiotic-treatment conditions. We speculate that these common genes are essential for antibiotic resistance in DR1. Treatment with the 4 antibiotics produced diverse physiological and phenotypic changes. Km treatment induced the most dramatic phenotypic changes. Examination of mutation frequency and DNA-repair capability demonstrated the induction of the SOS response in Acinetobacter especially under Nor treatment. Based on the RNA-seq analysis, the glyoxylate-bypass genes of the citrate cycle were specifically upregulated under Amp treatment. We also identified newly recognized non-coding small RNAs of the DR1 strain, which were also confirmed by Northern blot analysis. These results reveal that treatment with antibiotics of distinct classes differentially affected the gene expression and physiology of DR1 cells. This study expands our understanding of the molecular mechanisms of antibiotic-stress response of environment-originated bacteria and provides a basis for future investigations.

  12. Acute first-time hamstring strains during high-speed running: a longitudinal study including clinical and magnetic resonance imaging findings.

    PubMed

    Askling, Carl M; Tengvar, Magnus; Saartok, Tönu; Thorstensson, Alf

    2007-02-01

    Hamstring muscle strain is one of the most common injuries in sports. Still, knowledge is limited about the progression of clinical and magnetic resonance imaging characteristics and their association with recovery time in athletes. Knowing the anatomical location and extent of an acute first-time hamstring strain in athletes is critical for the prognosis of recovery time. Case series (prognosis); Level of evidence, 2. Eighteen elite sprinters with acute first-time hamstring strains were prospectively included in the study. All subjects were examined, clinically and with magnetic resonance imaging, on 4 occasions after injury: at day 2 to 4, 10, 21, and 42. The clinical follow-up period was 2 years. All sprinters were injured during competitive sprinting, and the primary injuries were all located in the long head of the biceps femoris muscle. There was an association between the time to return to pre-injury level (median, 16; range, 6-50 weeks) and the extent of the injury, as indicated by the magnetic resonance imaging parameters. Involvement of the proximal free tendon, as estimated by MRI, and proximity to the ischial tuberosity, as estimated both by palpation and magnetic resonance imaging, were associated with longer time to return to pre-injury level. Careful palpation during the first 3 weeks after injury and magnetic resonance imaging investigation performed during the first 6 weeks after injury provide valuable information that can be used to predict the time to return to pre-injury level of performance in elite sprinting.

  13. [Evolution of antimicrobial susceptibility of Acinetobacter baumannii clinical isolates].

    PubMed

    López-Hernández, S; Alarcón, T; López-Brea, M

    2000-12-01

    Acinetobacter baumannii is a microorganism frequently implicated in colonization and infection in hospitalized patients. An increase of resistance has been observed in recent years making these infections difficult to treat. The in vitro activity of 24 antibiotics, 15 betalactam agents and nine nonbetalactams, was studied in 156 A. baumannii clinical isolates. The strains were collected from different clinical samples obtained from inpatients (92%) and 8% were from outpatients. Evolution of susceptibility from January 1995 to December 1997 was studied. MIC of the following antibiotics was determined by the agar dilution method: ampicillin, ticarcillin, piperacillin, ampicillin-sulbactam, amoxicillin- clavulanic acid, ticarcillin-clavulanic acid, piperacillin-tazobactam, cefotaxime, ceftazidime, cefepime, imipenem, meropenem, clavulanic acid, sulbactam, tazobactam, amikacin, gentamicin, tobramycin, ofloxacin, doxycycline, fosfomycin, rifampin, azithromycin and colistin. Low antimicrobial susceptibility was observed in most A. baumannii strains. Colistin, imipenem, meropenem and ampicillin-sulbactam showed the greatest susceptibility (100, 88.4, 88.4 and 84.6%, respectively). A. baumannii strains from inpatients showed a lower antimicrobial susceptibility than strains from outpatients, who showed a high percentage of susceptibility to most antibiotics. Rifampin and azithromycin showed certain in vitro activity against the most susceptible A. baumannii strains. A progressive decrease in susceptibility to most antibiotics was observed during the period studied. Carbapenem-resistant A. baumannii emerged in 1996 and increased in 1997.

  14. Molecular Analysis of the Acinetobacter baumannii Biofilm-Associated Protein

    PubMed Central

    Goh, H. M. Sharon; Beatson, Scott A.; Totsika, Makrina; Moriel, Danilo G.; Phan, Minh-Duy; Szubert, Jan; Runnegar, Naomi; Sidjabat, Hanna E.; Paterson, David L.; Nimmo, Graeme R.; Lipman, Jeffrey

    2013-01-01

    Acinetobacter baumannii is a multidrug-resistant pathogen associated with hospital outbreaks of infection across the globe, particularly in the intensive care unit. The ability of A. baumannii to survive in the hospital environment for long periods is linked to antibiotic resistance and its capacity to form biofilms. Here we studied the prevalence, expression, and function of the A. baumannii biofilm-associated protein (Bap) in 24 carbapenem-resistant A. baumannii ST92 strains isolated from a single institution over a 10-year period. The bap gene was highly prevalent, with 22/24 strains being positive for bap by PCR. Partial sequencing of bap was performed on the index case strain MS1968 and revealed it to be a large and highly repetitive gene approximately 16 kb in size. Phylogenetic analysis employing a 1,948-amino-acid region corresponding to the C terminus of Bap showed that BapMS1968 clusters with Bap sequences from clonal complex 2 (CC2) strains ACICU, TCDC-AB0715, and 1656-2 and is distinct from Bap in CC1 strains. By using overlapping PCR, the bapMS1968 gene was cloned, and its expression in a recombinant Escherichia coli strain resulted in increased biofilm formation. A Bap-specific antibody was generated, and Western blot analysis showed that the majority of A. baumannii strains expressed an ∼200-kDa Bap protein. Further analysis of three Bap-positive A. baumannii strains demonstrated that Bap is expressed at the cell surface and is associated with biofilm formation. Finally, biofilm formation by these Bap-positive strains could be inhibited by affinity-purified Bap antibodies, demonstrating the direct contribution of Bap to biofilm growth by A. baumannii clinical isolates. PMID:23956398

  15. Diversity in Secondary Metabolites Including Mycotoxins from Strains of Aspergillus Section Nigri Isolated from Raw Cashew Nuts from Benin, West Africa.

    PubMed

    Lamboni, Yendouban; Nielsen, Kristian F; Linnemann, Anita R; Gezgin, Yüksel; Hell, Kerstin; Nout, Martinus J R; Smid, Eddy J; Tamo, Manuele; van Boekel, Martinus A J S; Hoof, Jakob Blæsbjerg; Frisvad, Jens Christian

    2016-01-01

    In a previous study, raw cashew kernels were assayed for the fungal contamination focusing on strains belonging to the genus Aspergillus and on aflatoxins producers. These samples showed high contamination with Aspergillus section Nigri species and absence of aflatoxins. To investigate the diversity of secondary metabolites, including mycotoxins, the species of A. section Nigri may produce and thus threaten to contaminate the raw cashew kernels, 150 strains were isolated from cashew samples and assayed for their production of secondary metabolites using liquid chromatography high resolution mass spectrometry (LC-HRMS). Seven species of black Aspergilli were isolated based on morphological and chemical identification: A. tubingensis (44%), A. niger (32%), A. brasiliensis (10%), A. carbonarius (8.7%), A. luchuensis (2.7%), A. aculeatus (2%) and A. aculeatinus (0.7%). From these, 45 metabolites and their isomers were identified. Aurasperone and pyranonigrin A, produced by all species excluding A. aculeatus and A. aculeatinus, were most prevalent and were encountered in 146 (97.3%) and 145 (95.7%) isolates, respectively. Three mycotoxins groups were detected: fumonisins (B2 and B4) (2.7%) ochratoxin A (13.3%), and secalonic acids (2%), indicating that these mycotoxins could occur in raw cashew nuts. Thirty strains of black Aspergilli were randomly sampled for verification of species identity based on sequences of β-tubulin and calmodulin genes. Among them, 27 isolates were positive to the primers used and 11 were identified as A. niger, 7 as A. tubingensis, 6 as A. carbonarius, 2 as A. luchuensis and 1 as A. welwitschiae confirming the species names as based on morphology and chemical features. These strains clustered in 5 clades in A. section Nigri. Chemical profile clustering also showed also 5 groups confirming the species specific metabolites production.

  16. Diversity in Secondary Metabolites Including Mycotoxins from Strains of Aspergillus Section Nigri Isolated from Raw Cashew Nuts from Benin, West Africa

    PubMed Central

    Lamboni, Yendouban; Nielsen, Kristian F.; Linnemann, Anita R.; Gezgin, Yüksel; Hell, Kerstin; Nout, Martinus J. R.; Smid, Eddy J.; Tamo, Manuele; van Boekel, Martinus A. J. S.; Hoof, Jakob Blæsbjerg; Frisvad, Jens Christian

    2016-01-01

    In a previous study, raw cashew kernels were assayed for the fungal contamination focusing on strains belonging to the genus Aspergillus and on aflatoxins producers. These samples showed high contamination with Aspergillus section Nigri species and absence of aflatoxins. To investigate the diversity of secondary metabolites, including mycotoxins, the species of A. section Nigri may produce and thus threaten to contaminate the raw cashew kernels, 150 strains were isolated from cashew samples and assayed for their production of secondary metabolites using liquid chromatography high resolution mass spectrometry (LC-HRMS). Seven species of black Aspergilli were isolated based on morphological and chemical identification: A. tubingensis (44%), A. niger (32%), A. brasiliensis (10%), A. carbonarius (8.7%), A. luchuensis (2.7%), A. aculeatus (2%) and A. aculeatinus (0.7%). From these, 45 metabolites and their isomers were identified. Aurasperone and pyranonigrin A, produced by all species excluding A. aculeatus and A. aculeatinus, were most prevalent and were encountered in 146 (97.3%) and 145 (95.7%) isolates, respectively. Three mycotoxins groups were detected: fumonisins (B2 and B4) (2.7%) ochratoxin A (13.3%), and secalonic acids (2%), indicating that these mycotoxins could occur in raw cashew nuts. Thirty strains of black Aspergilli were randomly sampled for verification of species identity based on sequences of β-tubulin and calmodulin genes. Among them, 27 isolates were positive to the primers used and 11 were identified as A. niger, 7 as A. tubingensis, 6 as A. carbonarius, 2 as A. luchuensis and 1 as A. welwitschiae confirming the species names as based on morphology and chemical features. These strains clustered in 5 clades in A. section Nigri. Chemical profile clustering also showed also 5 groups confirming the species specific metabolites production. PMID:27768708

  17. Utility of Whole-Genome Sequencing in Characterizing Acinetobacter Epidemiology and Analyzing Hospital Outbreaks.

    PubMed

    Fitzpatrick, Margaret A; Ozer, Egon A; Hauser, Alan R

    2016-03-01

    Acinetobacter baumannii frequently causes nosocomial infections and outbreaks. Whole-genome sequencing (WGS) is a promising technique for strain typing and outbreak investigations. We compared the performance of conventional methods with WGS for strain typing clinical Acinetobacter isolates and analyzing a carbapenem-resistant A. baumannii (CRAB) outbreak. We performed two band-based typing techniques (pulsed-field gel electrophoresis and repetitive extragenic palindromic-PCR), multilocus sequence type (MLST) analysis, and WGS on 148 Acinetobacter calcoaceticus-A. baumannii complex bloodstream isolates collected from a single hospital from 2005 to 2012. Phylogenetic trees inferred from core-genome single nucleotide polymorphisms (SNPs) confirmed three Acinetobacter species within this collection. Four major A. baumannii clonal lineages (as defined by MLST) circulated during the study, three of which are globally distributed and one of which is novel. WGS indicated that a threshold of 2,500 core SNPs accurately distinguished A. baumannii isolates from different clonal lineages. The band-based techniques performed poorly in assigning isolates to clonal lineages and exhibited little agreement with sequence-based techniques. After applying WGS to a CRAB outbreak that occurred during the study, we identified a threshold of 2.5 core SNPs that distinguished nonoutbreak from outbreak strains. WGS was more discriminatory than the band-based techniques and was used to construct a more accurate transmission map that resolved many of the plausible transmission routes suggested by epidemiologic links. Our study demonstrates that WGS is superior to conventional techniques for A. baumannii strain typing and outbreak analysis. These findings support the incorporation of WGS into health care infection prevention efforts.

  18. Utility of Whole-Genome Sequencing in Characterizing Acinetobacter Epidemiology and Analyzing Hospital Outbreaks

    PubMed Central

    Fitzpatrick, Margaret A.; Hauser, Alan R.

    2015-01-01

    Acinetobacter baumannii frequently causes nosocomial infections and outbreaks. Whole-genome sequencing (WGS) is a promising technique for strain typing and outbreak investigations. We compared the performance of conventional methods with WGS for strain typing clinical Acinetobacter isolates and analyzing a carbapenem-resistant A. baumannii (CRAB) outbreak. We performed two band-based typing techniques (pulsed-field gel electrophoresis and repetitive extragenic palindromic-PCR), multilocus sequence type (MLST) analysis, and WGS on 148 Acinetobacter calcoaceticus-A. baumannii complex bloodstream isolates collected from a single hospital from 2005 to 2012. Phylogenetic trees inferred from core-genome single nucleotide polymorphisms (SNPs) confirmed three Acinetobacter species within this collection. Four major A. baumannii clonal lineages (as defined by MLST) circulated during the study, three of which are globally distributed and one of which is novel. WGS indicated that a threshold of 2,500 core SNPs accurately distinguished A. baumannii isolates from different clonal lineages. The band-based techniques performed poorly in assigning isolates to clonal lineages and exhibited little agreement with sequence-based techniques. After applying WGS to a CRAB outbreak that occurred during the study, we identified a threshold of 2.5 core SNPs that distinguished nonoutbreak from outbreak strains. WGS was more discriminatory than the band-based techniques and was used to construct a more accurate transmission map that resolved many of the plausible transmission routes suggested by epidemiologic links. Our study demonstrates that WGS is superior to conventional techniques for A. baumannii strain typing and outbreak analysis. These findings support the incorporation of WGS into health care infection prevention efforts. PMID:26699703

  19. Whole-Genome Sequence of Acinetobacter pittii HUMV-6483 Isolated from Human Urine

    PubMed Central

    Chapartegui-González, Itziar; Lázaro-Díez, María; Redondo-Salvo, Santiago; Alted-Pérez, Laura; Ocejo-Vinyals, Javier Gonzalo; Navas, Jesús

    2017-01-01

    ABSTRACT Acinetobacter pittii strain HUMV-6483 was obtained from urine from an adult patient. We report here its complete genome assembly using PacBio single-molecule real-time sequencing, which resulted in a chromosome with 4.07 Mb and a circular contig of 112 kb. About 3,953 protein-coding genes are predicted from this assembly. PMID:28729271

  20. Whole-Genome Sequence of Acinetobacter pittii HUMV-6483 Isolated from Human Urine.

    PubMed

    Chapartegui-González, Itziar; Lázaro-Díez, María; Redondo-Salvo, Santiago; Alted-Pérez, Laura; Ocejo-Vinyals, Javier Gonzalo; Navas, Jesús; Ramos-Vivas, José

    2017-07-20

    Acinetobacter pittii strain HUMV-6483 was obtained from urine from an adult patient. We report here its complete genome assembly using PacBio single-molecule real-time sequencing, which resulted in a chromosome with 4.07 Mb and a circular contig of 112 kb. About 3,953 protein-coding genes are predicted from this assembly. Copyright © 2017 Chapartegui-González et al.

  1. Role of OmpA in the Multidrug Resistance Phenotype of Acinetobacter baumannii

    PubMed Central

    Fàbrega, Anna; Roca, Ignasi; Sánchez-Encinales, Viviana; Vila, Jordi; Pachón, Jerónimo

    2014-01-01

    Acinetobacter baumannii has emerged as a nosocomial pathogen with an increased prevalence of multidrug-resistant strains. The role of the outer membrane protein A (OmpA) in antimicrobial resistance remains poorly understood. In this report, disruption of the ompA gene led to decreased MICs of chloramphenicol, aztreonam, and nalidixic acid. We have characterized, for the first time, the contribution of OmpA in the antimicrobial resistance phenotype of A. baumannii. PMID:24379205

  2. Evaluation of a Loop-Mediated Isothermal Amplification-Based Methodology To Detect Carbapenemase Carriage in Acinetobacter Clinical Isolates

    PubMed Central

    Vergara, Andrea; Zboromyrska, Yuliya; Mosqueda, Noraida; Morosini, María Isabel; García-Fernández, Sergio; Roca, Ignasi; Cantón, Rafael; Marco, Francesc

    2014-01-01

    Carbapenem-resistant Acinetobacter baumannii is a major source of nosocomial infections worldwide and is mainly associated with the acquisition of OXA-type carbapenemases and, to a lesser extent, metallo-β-lactamases (MBLs). In this study, 82 nonepidemiologically related Acinetobacter strains carrying different types of OXA or MBL enzymes were tested using the Eazyplex system, a loop-mediated isothermal amplification (LAMP)-based method to rapidly detect carbapenemase carriage. The presence/absence of carbapenem-hydrolyzing enzymes was correctly determined for all isolates in <30 min. PMID:25224010

  3. Pillows, an unexpected source of Acinetobacter.

    PubMed

    Weernink, A; Severin, W P; Tjernberg, I; Dijkshoorn, L

    1995-03-01

    From 1989 until 1992 an increase in the number of isolations of Acinetobacter was observed in a community hospital in The Netherlands. The organisms were spread throughout the hospital and a common source was suspected. Feather pillows were found to harbour high numbers of acinetobacters. Replacement with synthetic pillows and correction of the laundry procedure resulted in a significant reduction of Acinetobacter isolations. A number of isolates from patients and from pillows were indistinguishable using biotyping, antibiogram typing and cell envelope protein typing. By the use of DNA-DNA hybridization most isolates were identified to A. baumannii and the unnamed closely related genomic species 13. A number of isolates, mostly from pillows, were identified as A. radioresistens. The outcome of cultivation, intervention and typing suggests that the feather pillows played an important role in the outbreak.

  4. Clinical implications of glycoproteomics for Acinetobacter baumannii.

    PubMed

    Kinsella, Rachel L; Scott, Nichollas E; Feldman, Mario F

    2015-02-01

    The opportunistic human pathogen Acinetobacter baumannii persists in the healthcare setting because of its ability to survive exposure to various antimicrobial and sterilization agents. A. baumannii's ability to cause multiple infection types complicates diagnosis and treatment. Rapid detection of A. baumannii infections would likely improve treatment outcomes. Recently published Acinetobacter glycoproteomic data show the prevalence of O-linked glycoproteins, suggesting the possibility for an O-glycan-based detection technology. O-glycan biosynthesis is required for protein glycosylation and capsular polysaccharide production in A. baumannii. Recent publications demonstrate key roles for protein glycosylation and capsular polysaccharide in the pathogenicity of A. baumannii. Targeted antimicrobial development against O-glycan biosynthesis may produce new effective treatment options for A. baumannii infections. Here, we discuss how the data gathered through Acinetobacter glycoproteomics can be used to develop technologies for rapid diagnosis and reveal potential antimicrobial targets. In addition, we consider the efficacy of glycoconjugate vaccine development against A. baumannii.

  5. Unique features revealed by the genome sequence of Acinetobacter sp. ADP1, a versatile and naturally transformation competent bacterium

    PubMed Central

    Barbe, Valérie; Vallenet, David; Fonknechten, Nuria; Kreimeyer, Annett; Oztas, Sophie; Labarre, Laurent; Cruveiller, Stéphane; Robert, Catherine; Duprat, Simone; Wincker, Patrick; Ornston, L. Nicholas; Weissenbach, Jean; Marlière, Philippe; Cohen, Georges N.; Médigue, Claudine

    2004-01-01

    Acinetobacter sp. strain ADP1 is a nutritionally versatile soil bacterium closely related to representatives of the well-characterized Pseudomonas aeruginosa and Pseudomonas putida. Unlike these bacteria, the Acinetobacter ADP1 is highly competent for natural transformation which affords extraordinary convenience for genetic manipulation. The circular chromosome of the Acinetobacter ADP1, presented here, encodes 3325 predicted coding sequences, of which 60% have been classified based on sequence similarity to other documented proteins. The close evolutionary proximity of Acinetobacter and Pseudomonas species, as judged by the sequences of their 16S RNA genes and by the highest level of bidirectional best hits, contrasts with the extensive divergence in the GC content of their DNA (40 versus 62%). The chromosomes also differ significantly in size, with the Acinetobacter ADP1 chromosome <60% of the length of the Pseudomonas counterparts. Genome analysis of the Acinetobacter ADP1 revealed genes for metabolic pathways involved in utilization of a large variety of compounds. Almost all of these genes, with orthologs that are scattered in other species, are located in five major ‘islands of catabolic diversity’, now an apparent ‘archipelago of catabolic diversity’, within one-quarter of the overall genome. Acinetobacter ADP1 displays many features of other aerobic soil bacteria with metabolism oriented toward the degradation of organic compounds found in their natural habitat. A distinguishing feature of this genome is the absence of a gene corresponding to pyruvate kinase, the enzyme that generally catalyzes the terminal step in conversion of carbohydrates to pyruvate for respiration by the citric acid cycle. This finding supports the view that the cycle itself is centrally geared to the catabolic capabilities of this exceptionally versatile organism. PMID:15514110

  6. Investigation and management of multidrug-resistant Acinetobacter baumannii spread in a French medical intensive care unit: one outbreak may hide another.

    PubMed

    Bourigault, Céline; Corvec, Stéphane; Bretonnière, Cédric; Guillouzouic, Aurélie; Crémet, Lise; Marraillac, Julie; Juvin, Marie-Emmanuelle; Bemer, Pascale; Le Gallou, Florence; Reynaud, Alain; Boutoille, David; Villers, Daniel; Lepelletier, Didier

    2013-07-01

    An outbreak in a medical intensive care unit was due to an OXA-23-producing Acinetobacter baumannii strain imported from a repatriate hospitalized in Singapore. This outbreak revealed another multidrug resistant epidemic strain that had been present in the hospital for 2 years. Both outbreaks were controlled after 9 months of an extensive infection control program.

  7. Longitudinal surveillance for meningitis by Acinetobacter in a large urban setting in Brazil

    PubMed Central

    Coelho-Souza, Talita; Reis, Joice N.; Martins, Natacha; Martins, Ianick Souto; Menezes, Ana Paula O.; Reis, Mitermayer G.; Silva, Neide O.; Dias, Rubens C. S.; Riley, Lee W.; Moreira, Beatriz Meurer

    2013-01-01

    The study aim was to describe the emergency of carbapenem resistance and clonal complexes (CC), defined by multilocus sequence typing (MLST), in Acinetobacter baumannii in a surveillance system for meningitis. Starting in 1996 at an urban setting of Brazil, surveillance detected meningitis by Acinetobacter sp for the first time in 2002. Until 2008, 35 isolates were saved. Carbapenem resistance emerged in 2006, reaching 70% of A. baumannii isolates in 2008, including one colistin-resistant. A. baumannii belonged to CC113/79 (University of Oxford/ Institute Pasteur schemes), CC235/162 and CC103/15. Dissemination of infections resistant to all antimicrobial agents may occur in the future. PMID:23398654

  8. Iron-Regulated Phospholipase C Activity Contributes to the Cytolytic Activity and Virulence of Acinetobacter baumannii

    PubMed Central

    Fiester, Steven E.; Schmidt, Robert E.; Beckett, Amber C.; Ticak, Tomislav; Carrier, Mary V.; Ghosh, Rajarshi; Ohneck, Emily J.; Metz, Maeva L.; Sellin Jeffries, Marlo K.; Actis, Luis A.

    2016-01-01

    Acinetobacter baumannii is an opportunistic Gram-negative pathogen that causes a wide range of infections including pneumonia, septicemia, necrotizing fasciitis and severe wound and urinary tract infections. Analysis of A. baumannii representative strains grown in Chelex 100-treated medium for hemolytic activity demonstrated that this pathogen is increasingly hemolytic to sheep, human and horse erythrocytes, which interestingly contain increasing amounts of phosphatidylcholine in their membranes. Bioinformatic, genetic and functional analyses of 19 A. baumannii isolates showed that the genomes of each strain contained two phosphatidylcholine-specific phospholipase C (PC-PLC) genes, which were named plc1 and plc2. Accordingly, all of these strains were significantly hemolytic to horse erythrocytes and their culture supernatants tested positive for PC-PLC activity. Further analyses showed that the transcriptional expression of plc1 and plc2 and the production of phospholipase and thus hemolytic activity increased when bacteria were cultured under iron-chelation as compared to iron-rich conditions. Testing of the A. baumannii ATCC 19606T plc1::aph-FRT and plc2::aph isogenic insertion derivatives showed that these mutants had a significantly reduced PC-PLC activity as compared to the parental strain, while testing of plc1::ermAM/plc2::aph demonstrated that this double PC-PLC isogenic mutant expressed significantly reduced cytolytic and hemolytic activity. Interestingly, only plc1 was shown to contribute significantly to A. baumannii virulence using the Galleria mellonella infection model. Taken together, our data demonstrate that both PLC1 and PLC2, which have diverged from a common ancestor, play a concerted role in hemolytic and cytolytic activities; although PLC1 seems to play a more critical role in the virulence of A. baumannii when tested in an invertebrate model. These activities would provide access to intracellular iron stores this pathogen could use during

  9. Characterization of newly isolated lytic bacteriophages active against Acinetobacter baumannii.

    PubMed

    Merabishvili, Maia; Vandenheuvel, Dieter; Kropinski, Andrew M; Mast, Jan; De Vos, Daniel; Verbeken, Gilbert; Noben, Jean-Paul; Lavigne, Rob; Vaneechoutte, Mario; Pirnay, Jean-Paul

    2014-01-01

    Based on genotyping and host range, two newly isolated lytic bacteriophages, myovirus vB_AbaM_Acibel004 and podovirus vB_AbaP_Acibel007, active against Acinetobacter baumannii clinical strains, were selected from a new phage library for further characterization. The complete genomes of the two phages were analyzed. Both phages are characterized by broad host range and essential features of potential therapeutic phages, such as short latent period (27 and 21 min, respectively), high burst size (125 and 145, respectively), stability of activity in liquid culture and low frequency of occurrence of phage-resistant mutant bacterial cells. Genomic analysis showed that while Acibel004 represents a novel bacteriophage with resemblance to some unclassified Pseudomonas aeruginosa phages, Acibel007 belongs to the well-characterized genus of the Phikmvlikevirus. The newly isolated phages can serve as potential candidates for phage cocktails to control A. baumannii infections.

  10. Inactivation of Phospholipase D Diminishes Acinetobacter baumannii Pathogenesis▿ †

    PubMed Central

    Jacobs, Anna C.; Hood, Indriati; Boyd, Kelli L.; Olson, Patrick D.; Morrison, John M.; Carson, Steven; Sayood, Khalid; Iwen, Peter C.; Skaar, Eric P.; Dunman, Paul M.

    2010-01-01

    Acinetobacter baumannii is an emerging bacterial pathogen of considerable health care concern. Nonetheless, relatively little is known about the organism's virulence factors or their regulatory networks. Septicemia and ventilator-associated pneumonia are two of the more severe forms of A. baumannii disease. To identify virulence factors that may contribute to these disease processes, genetically diverse A. baumannii clinical isolates were evaluated for the ability to proliferate in human serum. A transposon mutant library was created in a strain background that propagated well in serum and screened for members with decreased serum growth. The results revealed that disruption of A. baumannii phospholipase D (PLD) caused a reduction in the organism's ability to thrive in serum, a deficiency in epithelial cell invasion, and diminished pathogenesis in a murine model of pneumonia. Collectively, these results suggest that PLD is an A. baumannii virulence factor. PMID:20194595

  11. Heterotrophic nitrogen removal by Acinetobacter sp. Y1 isolated from coke plant wastewater.

    PubMed

    Liu, YuXiang; Hu, Tingting; Song, Yujie; Chen, Hongping; Lv, YongKang

    2015-11-01

    A strain of Acinetobacter sp. Y1, which exhibited an amazing ability to remove ammonium, nitrite and nitrate, was isolated from the activated sludge of a coking wastewater treatment plant. The aim of this work was to study the ability, influence factors and possible pathway of nitrogen removal by Acinetobacter sp. Y1. Results showed that maximum removal rate of NH4(+)-N by the strain was 10.28 mg-N/L/h. Carbon source had significant influence on the growth and ammonium removal efficiencies of strain Y1. Pyruvate, citrate and acetate were favourable carbon sources for the strain. Temperature, pH value and shaking speed could affect the growth and nitrogen removal ability. Nitrate or nitrite could be used as a sole nitrogen source for the growth and removed efficiently by the strain. N2 levels increased to 53.74%, 50.21% and 55.13% within 36 h when 100 mg/L NH4(+)-N, NO2(-)-N or NO3(-) -N was used as sole nitrogen source in the gas detection experiment. The activities of hydroxylamine oxidoreductase (HAO), nitrate reductase (NR) and nitrite reductase (NiR), which are key enzymes in heterotrophic nitrification and aerobic denitrification, were all detectable in the strain. Consequently, a possible pathway for ammonium removal by the strain was also suggested.

  12. Multilocus Sequence Typing Analysis of Carbapenem-Resistant Acinetobacter baumannii in a Chinese Burns Institute

    PubMed Central

    Huang, Guangtao; Yin, Supeng; Gong, Yali; Zhao, Xia; Zou, Lingyun; Jiang, Bei; Dong, Zhiwei; Chen, Yu; Chen, Jing; Jin, Shouguang; Yuan, Zhiqiang; Peng, Yizhi

    2016-01-01

    Acinetobacter baumannii is a leading pathogen responsible for nosocomial infections. The emergence of carbapenem-resistant A. baumannii (CRAB) has left few effective antibiotics for clinicians to use. To investigate the temporal evolutionary relationships among CRAB strains, we collected 248 CRAB isolates from a Chinese burns institute over 3 years. The prevalence of the OXA-23 gene was detected by polymerase chain reaction. Multilocus sequence typing was used to type the CRAB strains and eBURST was used to analyze their evolutionary relationships. Wound surfaces (41%), sputa (24%), catheters (15%), and bloods (14%) were the four dominant isolation sources. Except for minocycline (33.5%) and sulbactam/cefoperazone (74.6%), these CRAB strains showed high resistance rates (>90%) to 16 tested antibiotics. The 248 isolates fall into 26 sequence types (STs), including nine known STs and 17 unknown STs. The majority (230/248) of these isolates belong to clonal complex 92 (CC92), including eight isolates belonging to seven unreported STs. A new CC containing 11 isolates grouped into four new STs was identified. The OXA-23 gene was detected at high prevalence among the CRAB isolates and the prevalence rate among the various STs differed. The majority of the isolates displayed a close evolutionary relationship, suggesting that serious nosocomial spreading and nosocomial infections of CRAB have occurred in the burn unit. In conclusion, the main CC for CRAB in this Chinese burn unit remained unchanged during the 3-year study period, and a new CC was identified. CC92 was the dominant complex, and more attention should be directed toward monitoring the new CC we have identified herein. PMID:27881972

  13. Complexity of Complement Resistance Factors Expressed by Acinetobacter baumannii Needed for Survival in Human Serum.

    PubMed

    Sanchez-Larrayoz, Amaro F; Elhosseiny, Noha M; Chevrette, Marc G; Fu, Yang; Giunta, Peter; Spallanzani, Raúl G; Ravi, Keerthikka; Pier, Gerald B; Lory, Stephen; Maira-Litrán, Tomás

    2017-08-30

    Acinetobacter baumannii is a bacterial pathogen with increasing impact in healthcare settings, due in part to this organism's resistance to many antimicrobial agents, with pneumonia and bacteremia as the most common manifestations of disease. A significant proportion of clinically relevant A. baumannii strains are resistant to killing by normal human serum (NHS), an observation supported in this study by showing that 12 out of 15 genetically diverse strains of A. baumannii are resistant to NHS killing. To expand our understanding of the genetic basis of A. baumannii serum resistance, a transposon (Tn) sequencing (Tn-seq) approach was used to identify genes contributing to this trait. An ordered Tn library in strain AB5075 with insertions in every nonessential gene was subjected to selection in NHS. We identified 50 genes essential for the survival of A. baumannii in NHS, including already known serum resistance factors, and many novel genes not previously associated with serum resistance. This latter group included the maintenance of lipid asymmetry genetic pathway as a key determinant in protecting A. baumannii from the bactericidal activity of NHS via the alternative complement pathway. Follow-up studies validated the role of eight additional genes identified by Tn-seq in A. baumannii resistance to killing by NHS but not by normal mouse serum, highlighting the human species specificity of A. baumannii serum resistance. The identification of a large number of genes essential for serum resistance in A. baumannii indicates the degree of complexity needed for this phenotype, which might reflect a general pattern that pathogens rely on to cause serious infections. Copyright © 2017 by The American Association of Immunologists, Inc.

  14. Repurposing the anticancer drug mitomycin C for the treatment of persistent Acinetobacter baumannii infections.

    PubMed

    Cruz-Muñiz, Martha Yumiko; López-Jacome, Luis Esau; Hernández-Durán, Melissa; Franco-Cendejas, Rafael; Licona-Limón, Paula; Ramos-Balderas, Jose Luis; Martinéz-Vázquez, Mariano; Belmont-Díaz, Javier A; Wood, Thomas K; García-Contreras, Rodolfo

    2017-01-01

    Acinetobacter baumannii is an emergent opportunistic bacterial pathogen responsible for recalcitrant infections owing to its high intrinsic tolerance to most antibiotics; therefore, suitable strategies to treat these infections are needed. One plausible approach is the repurposing of drugs that are already in use. Among them, anticancer drugs may be especially useful due their cytotoxic activities and ample similarities between bacterial infections and growing tumours. In this work, the effectiveness of four anticancer drugs on the growth of A. baumannii ATTC BAA-747 was evaluated, including the antimetabolite 5-fluorouracil and three DNA crosslinkers, namely cisplatin, mitomycin C (MMC) and merphalan. MMC was the most effective drug, having a minimum inhibitory concentration for 50% of growth in Luria-Bertani medium at ca. 7 µg/mL and completely inhibiting growth at 25 µg/mL. Hence, MMC was tested against a panel of 21 clinical isolates, including 18 multidrug-resistant (MDR) isolates, 3 of which were sensitive only to colistin. The minimum inhibitory concentrations and minimum bactericidal concentrations of MMC in all tested strains were found to be similar to those of A. baumannii ATCC BAA-747, and MMC also effectively killed stationary-phase, persister and biofilm cells. Moreover, MMC was able to increase survival of the insect larvae Galleria mellonella against an otherwise lethal A. baumannii infection from 0% to ≥53% for the antibiotic-sensitive A. baumannii ATCC BAA-747 strain and the MDR strains A560 and A578. Therefore, MMC is highly effective at killing the emergent opportunistic pathogen A. baumannii.

  15. In vitro and in vivo activities of E-101 solution against Acinetobacter baumannii isolates from U.S. military personnel.

    PubMed

    Denys, G A; Davis, J C; O'Hanley, P D; Stephens, J T

    2011-07-01

    We evaluated the in vitro and in vivo activity of a novel topical myeloperoxidase-mediated antimicrobial, E-101 solution, against 5 multidrug-resistant Acinetobacter baumannii isolates recovered from wounded American soldiers. Time-kill studies demonstrated rapid bactericidal activity against all A. baumannii strains tested in the presence of 3% blood. The in vitro bactericidal activity of E-101 solution against A. baumannii strains was confirmed in a full-thickness excision rat model. Additional in vivo studies appear warranted.

  16. Detection of Quorum Sensing Signal Molecules and Identification of an Autoinducer Synthase Gene among Biofilm Forming Clinical Isolates of Acinetobacter spp.

    PubMed Central

    Anbazhagan, Deepa; Mansor, Marzida; Yan, Gracie Ong Siok; Md Yusof, Mohd Yasim; Hassan, Hamimah; Sekaran, Shamala Devi

    2012-01-01

    Background Quorum sensing is a term that describes an environmental sensing system that allows bacteria to monitor their own population density which contributes significantly to the size and development of the biofilm. Many gram negative bacteria use N-acyl-homoserine lactones as quorum sensing signal molecules. In this study, we sought to find out if the biofilm formation among clinical isolates of Acinetobacter spp. is under the control of autoinducing quorum sensing molecules. Methodology/Principal Findings Biofilm formation among clinical isolates of Acinetobacter spp. was assessed and the production of signal molecules were detected with Chromobacterium violaceum CV026 biosensor system. Characterisation of autoinducers was carried out by mass spectrometric analysis. We have also reported the identification of an autoinducer synthase gene, abaΙ among the isolates that produce quorum sensing signal molecules and have reported that the mutation in the abaI gene influences their biofilm forming capabilities. Using a microtitre-plate assay it was shown that 60% of the 50 Acinetobacter spp. isolates significantly formed biofilms. Further detection with the biosensor strain showed that some of these isolates produced long chain signal molecules. Mass spectrometric analysis revealed that five of these isolates produced N-decanoyl homoserine lactone and two isolates produced acyl-homoserine lactone with a chain length equal to C12. The abaΙ gene was identified and a tetracycline mutant of the abaΙ gene was created and the inhibition in biofilm formation in the mutant was shown. Conclusions/Significance These data are of great significance as the signal molecules aid in biofilm formation which in turn confer various properties of pathogenicity to the clinical isolates including drug resistance. The use of quorum sensing signal blockers to attenuate bacterial pathogenicity is therefore highly attractive, particularly with respect to the emergence of multi antibiotic

  17. Detection of quorum sensing signal molecules and identification of an autoinducer synthase gene among biofilm forming clinical isolates of Acinetobacter spp.

    PubMed

    Anbazhagan, Deepa; Mansor, Marzida; Yan, Gracie Ong Siok; Md Yusof, Mohd Yasim; Hassan, Hamimah; Sekaran, Shamala Devi

    2012-01-01

    Quorum sensing is a term that describes an environmental sensing system that allows bacteria to monitor their own population density which contributes significantly to the size and development of the biofilm. Many gram negative bacteria use N-acyl-homoserine lactones as quorum sensing signal molecules. In this study, we sought to find out if the biofilm formation among clinical isolates of Acinetobacter spp. is under the control of autoinducing quorum sensing molecules. Biofilm formation among clinical isolates of Acinetobacter spp. was assessed and the production of signal molecules were detected with Chromobacterium violaceum CV026 biosensor system. Characterisation of autoinducers was carried out by mass spectrometric analysis. We have also reported the identification of an autoinducer synthase gene, abaΙ among the isolates that produce quorum sensing signal molecules and have reported that the mutation in the abaI gene influences their biofilm forming capabilities. Using a microtitre-plate assay it was shown that 60% of the 50 Acinetobacter spp. isolates significantly formed biofilms. Further detection with the biosensor strain showed that some of these isolates produced long chain signal molecules. Mass spectrometric analysis revealed that five of these isolates produced N-decanoyl homoserine lactone and two isolates produced acyl-homoserine lactone with a chain length equal to C(12). The abaΙ gene was identified and a tetracycline mutant of the abaΙ gene was created and the inhibition in biofilm formation in the mutant was shown. These data are of great significance as the signal molecules aid in biofilm formation which in turn confer various properties of pathogenicity to the clinical isolates including drug resistance. The use of quorum sensing signal blockers to attenuate bacterial pathogenicity is therefore highly attractive, particularly with respect to the emergence of multi antibiotic resistant bacteria.

  18. The pmrCAB operon mediates polymyxin resistance in Acinetobacter baumannii ATCC 17978 and clinical isolates through phosphoethanolamine modification of lipid A.

    PubMed

    Arroyo, Luis A; Herrera, Carmen M; Fernandez, Lucia; Hankins, Jessica V; Trent, M Stephen; Hancock, Robert E W

    2011-08-01

    The emergence of multidrug resistance among Acinetobacter baumannii is leading to an increasing dependence on the use of polymyxins as last-hope antibiotics. Here, we utilized genetic and biochemical methods to define the involvement of the pmrCAB operon in polymyxin resistance in this organism. Sequence analysis of 16 polymyxin B-resistant strains, including 6 spontaneous mutants derived from strain ATCC 17978 and 10 clinical isolates from diverse sources, revealed that they had independent mutations in the pmrB gene, encoding a sensor kinase, or in the response regulator PmrA. Knockout of the pmrB gene in two mutants and two clinical isolates led to a decrease in the polymyxin B susceptibility of these strains, which could be restored with the cloned pmrAB genes from the mutants but not from the wild type. Reverse transcription-quantitative PCR (RT-qPCR) analysis also showed a correlation between the expression of pmrC and polymyxin B resistance. Characterization of lipid A species from the mutant strains, by thin-layer chromatography and mass spectrometry, indicated that the addition of phosphoethanolamine to lipid A correlated with resistance. This addition is performed in Salmonella enterica serovar Typhimurium by the product of the pmrC gene, which is a homolog of the pmrC gene from Acinetobacter. Knockout of this gene in the mutant R2 [pmrB(T235I)] reversed resistance as well as phosphoethanolamine modification of lipid A. These results demonstrate that specific alterations in the sequence of the pmrCAB operon are responsible for resistance to polymyxins in A. baumannii.

  19. The pmrCAB Operon Mediates Polymyxin Resistance in Acinetobacter baumannii ATCC 17978 and Clinical Isolates through Phosphoethanolamine Modification of Lipid A▿

    PubMed Central

    Arroyo, Luis A.; Herrera, Carmen M.; Fernandez, Lucia; Hankins, Jessica V.; Trent, M. Stephen; Hancock, Robert E. W.

    2011-01-01

    The emergence of multidrug resistance among Acinetobacter baumannii is leading to an increasing dependence on the use of polymyxins as last-hope antibiotics. Here, we utilized genetic and biochemical methods to define the involvement of the pmrCAB operon in polymyxin resistance in this organism. Sequence analysis of 16 polymyxin B-resistant strains, including 6 spontaneous mutants derived from strain ATCC 17978 and 10 clinical isolates from diverse sources, revealed that they had independent mutations in the pmrB gene, encoding a sensor kinase, or in the response regulator PmrA. Knockout of the pmrB gene in two mutants and two clinical isolates led to a decrease in the polymyxin B susceptibility of these strains, which could be restored with the cloned pmrAB genes from the mutants but not from the wild type. Reverse transcription-quantitative PCR (RT-qPCR) analysis also showed a correlation between the expression of pmrC and polymyxin B resistance. Characterization of lipid A species from the mutant strains, by thin-layer chromatography and mass spectrometry, indicated that the addition of phosphoethanolamine to lipid A correlated with resistance. This addition is performed in Salmonella enterica serovar Typhimurium by the product of the pmrC gene, which is a homolog of the pmrC gene from Acinetobacter. Knockout of this gene in the mutant R2 [pmrB(T235I)] reversed resistance as well as phosphoethanolamine modification of lipid A. These results demonstrate that specific alterations in the sequence of the pmrCAB operon are responsible for resistance to polymyxins in A. baumannii. PMID:21646482

  20. Genomic characterization of two novel SAR11 isolates from the Red Sea, including the first strain of the SAR11 Ib clade.

    PubMed

    Jimenez-Infante, Francy; Ngugi, David Kamanda; Vinu, Manikandan; Blom, Jochen; Alam, Intikhab; Bajic, Vladimir B; Stingl, Ulrich

    2017-07-01

    The SAR11 clade (Pelagibacterales) is a diverse group that forms a monophyletic clade within the Alphaproteobacteria, and constitutes up to one third of all prokaryotic cells in the photic zone of most oceans. Pelagibacterales are very abundant in the warm and highly saline surface waters of the Red Sea, raising the question of adaptive traits of SAR11 populations in this water body and warmer oceans through the world. In this study, two pure cultures were successfully obtained from surface waters on the Red Sea: one isolate of subgroup Ia and one of the previously uncultured SAR11 Ib lineage. The novel genomes were very similar to each other and to genomes of isolates of SAR11 subgroup Ia (Ia pan-genome), both in terms of gene content and synteny. Among the genes that were not present in the Ia pan-genome, 108 (RS39, Ia) and 151 genes (RS40, Ib) were strain specific. Detailed analyses showed that only 51 (RS39, Ia) and 55 (RS40, Ib) of these strain-specific genes had not reported before on genome fragments of Pelagibacterales. Further analyses revealed the potential production of phosphonates by some SAR11 members and possible adaptations for oligotrophic life, including pentose sugar utilization and adhesion to marine particulate matter. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Lipopeptide biosurfactant production bacteria Acinetobacter sp. D3-2 and its biodegradation of crude oil.

    PubMed

    Bao, Mutai; Pi, Yongrui; Wang, Lina; Sun, Peiyan; Li, Yiming; Cao, Lixin

    2014-04-01

    In this work, a hydrocarbon-degrading bacterium D3-2 isolated from petroleum contaminated soil samples was investigated for its potential effect in biodegradation of crude oil. The strain was identified as Acinetobacter sp. D3-2 based on morphological, biochemical and phylogenetic analysis. The optimum environmental conditions for growth of the bacteria were determined to be pH 8.0, with a NaCl concentration of 3.0% (w/v) at 30 °C. Acinetobacter sp. D3-2 could utilize various hydrocarbon substrates as the sole carbon and energy source. From this study, we also found that the strain had the ability to produce biosurfactant, with the production of 0.52 g L(-1). The surface tension of the culture broth was decreased from 48.02 to 26.30 mN m(-1). The biosurfactant was determined to contain lipopeptide compounds based on laboratory analyses. By carrying out a crude oil degradation assay in an Erlenmeyer flask experiment and analyzing the hydrocarbon removal rate using gas chromatography, we found that Acinetobacter sp. D3-2 could grow at 30 °C in 3% NaCl solution with a preferable ability to degrade 82% hydrocarbons, showing that bioremediation does occur and plays a profound role during the oil reparation process.

  2. Continuous coculture degradation of selected polychlorinated biphenyl congeners by Acinetobacter spp. in an aerobic reactor system

    SciTech Connect

    Adriaens, P.; Focht, D.D. )

    1990-07-01

    A coculture of two Acinetobacter spp. was applied to degrade polychlorinated biphenyls during a 42-day incubation study in a continuous aerobic fixed-bed reactor system, filled with polyurethane foam boards as support for bacterial biofilm development. The reactor was supplied with mineral medium containing 500 ppm sodium benzoate as a growth (primary) substrate, while the incoming airstream was saturated with biphenyl vapors to induce for PCB cometabolism in Acinetobacter sp. strain P6. The chlorobenzoates thus generated from 4,4{prime}-dichlorobiphenyl (4,4{prime}-DCBP), 3,4-dichlorobiphenyl (3,4-DCBP), and 3,3{prime},4,4{prime}-tetrachlorobiphenyl were further metabolized by Acinetobacter sp. strain 4-CB1. The chlorobenzoate metabolites, as well as ring-fission product ({lambda}{sub max} = 442 nm) from the PCB congeners, accounted for the degradation of 63% (2.8 mM) of the 4,4{prime}-DCBP, 100% (0.5 mM) of the 3,4-DCBP, and 32% (0.12 mM) of the 3,3{prime},4,4{prime}-TCBP, the biofilm responded with a concurrent higher release of chlorobenzoates and chloride through cosubstrate utilization.

  3. The Physiological Contribution of Acinetobacter PcaK, a Transport System That Acts upon Protocatechuate, Can Be Masked by the Overlapping Specificity of VanK†

    PubMed Central

    D’Argenio, David A.; Segura, Ana; Coco, Wayne M.; Bünz, Patricia V.; Ornston, L. Nicholas

    1999-01-01

    VanK is the fourth member of the ubiquitous major facilitator superfamily of transport proteins to be identified that, together with PcaK, BenK, and MucK, contributes to aromatic catabolism in Acinetobacter sp. strain ADP1. VanK and PcaK have overlapping specificity for p-hydroxybenzoate and, most clearly, for protocatechuate: inactivation of both proteins severely impairs growth with protocatechuate, and the activity of either protein alone can mask the phenotype associated with inactivation of its homolog. Furthermore, vanK pcaK double-knockout mutants appear completely unable to grow in liquid culture with the hydroaromatic compound quinate, although such cells on plates convert quinate to protocatechuate, which then accumulates extracellularly and is readily visible as purple staining. This provides genetic evidence that quinate is converted to protocatechuate in the periplasm and is in line with the early argument that quinate catabolism should be physically separated from aromatic amino acid biosynthesis in the cytoplasm so as to avoid potential competition for intermediates common to both pathways. Previous studies of aromatic catabolism in Acinetobacter have taken advantage of the ability to select directly strains that contain a spontaneous mutation blocking the β-ketoadipate pathway and preventing the toxic accumulation of carboxymuconate. By using this procedure, strains with a mutation in structural or regulatory genes blocking degradation of vanillate, p-hydroxybenzoate, or protocatechuate were selected. In this study, the overlapping specificity of the VanK and PcaK permeases was exploited to directly select strains with a mutation in either vanK or pcaK. Spontaneous mutations identified in vanK include a hot spot for frameshift mutation due to contraction of a G6 mononucleotide repeat as well as point mutations producing amino acid substitutions useful for analysis of VanK structure and function. Preliminary second-site suppression analysis using

  4. Functional features of TonB energy transduction systems of Acinetobacter baumannii.

    PubMed

    Zimbler, Daniel L; Arivett, Brock A; Beckett, Amber C; Menke, Sharon M; Actis, Luis A

    2013-09-01

    Acinetobacter baumannii is an opportunistic pathogen that causes severe nosocomial infections. Strain ATCC 19606(T) utilizes the siderophore acinetobactin to acquire iron under iron-limiting conditions encountered in the host. Accordingly, the genome of this strain has three tonB genes encoding proteins for energy transduction functions needed for the active transport of nutrients, including iron, through the outer membrane. Phylogenetic analysis indicates that these tonB genes, which are present in the genomes of all sequenced A. baumannii strains, were acquired from different sources. Two of these genes occur as components of tonB-exbB-exbD operons and one as a monocistronic copy; all are actively transcribed in ATCC 19606(T). The abilities of components of these TonB systems to complement the growth defect of Escherichia coli W3110 mutants KP1344 (tonB) and RA1051 (exbBD) under iron-chelated conditions further support the roles of these TonB systems in iron acquisition. Mutagenesis analysis of ATCC 19606(T) tonB1 (subscripted numbers represent different copies of genes or proteins) and tonB2 supports this hypothesis: their inactivation results in growth defects in iron-chelated media, without affecting acinetobactin biosynthesis or the production of the acinetobactin outer membrane receptor protein BauA. In vivo assays using Galleria mellonella show that each TonB protein is involved in, but not essential for, bacterial virulence in this infection model. Furthermore, we observed that TonB2 plays a role in the ability of bacteria to bind to fibronectin and to adhere to A549 cells by uncharacterized mechanisms. Taken together, these results indicate that A. baumannii ATCC 19606(T) produces three independent TonB proteins, which appear to provide the energy-transducing functions needed for iron acquisition and cellular processes that play a role in the virulence of this pathogen.

  5. Functional Features of TonB Energy Transduction Systems of Acinetobacter baumannii

    PubMed Central

    Zimbler, Daniel L.; Arivett, Brock A.; Beckett, Amber C.; Menke, Sharon M.

    2013-01-01

    Acinetobacter baumannii is an opportunistic pathogen that causes severe nosocomial infections. Strain ATCC 19606T utilizes the siderophore acinetobactin to acquire iron under iron-limiting conditions encountered in the host. Accordingly, the genome of this strain has three tonB genes encoding proteins for energy transduction functions needed for the active transport of nutrients, including iron, through the outer membrane. Phylogenetic analysis indicates that these tonB genes, which are present in the genomes of all sequenced A. baumannii strains, were acquired from different sources. Two of these genes occur as components of tonB-exbB-exbD operons and one as a monocistronic copy; all are actively transcribed in ATCC 19606T. The abilities of components of these TonB systems to complement the growth defect of Escherichia coli W3110 mutants KP1344 (tonB) and RA1051 (exbBD) under iron-chelated conditions further support the roles of these TonB systems in iron acquisition. Mutagenesis analysis of ATCC 19606T tonB1 (subscripted numbers represent different copies of genes or proteins) and tonB2 supports this hypothesis: their inactivation results in growth defects in iron-chelated media, without affecting acinetobactin biosynthesis or the production of the acinetobactin outer membrane receptor protein BauA. In vivo assays using Galleria mellonella show that each TonB protein is involved in, but not essential for, bacterial virulence in this infection model. Furthermore, we observed that TonB2 plays a role in the ability of bacteria to bind to fibronectin and to adhere to A549 cells by uncharacterized mechanisms. Taken together, these results indicate that A. baumannii ATCC 19606T produces three independent TonB proteins, which appear to provide the energy-transducing functions needed for iron acquisition and cellular processes that play a role in the virulence of this pathogen. PMID:23817614

  6. In Vivo Fitness Adaptations of Colistin-Resistant Acinetobacter baumannii Isolates to Oxidative Stress

    PubMed Central

    Singh, Shweta S.; Alamneh, Yonas; Casella, Leila G.; Ernst, Robert K.; Lesho, Emil P.; Waterman, Paige E.; Zurawski, Daniel V.

    2016-01-01

    ABSTRACT The loss of fitness in colistin-resistant (CR) Acinetobacter baumannii was investigated using longitudinal isolates from the same patient. Early CR isolates were outcompeted by late CR isolates for growth in broth and survival in the lungs of mice. Fitness loss was associated with an increased susceptibility to oxidative stress since early CR strains had reduced in vitro survival in the presence of hydrogen peroxide and decreased catalase activity compared to that of late CR and colistin-susceptible (CS) strains. PMID:27993849

  7. Culturable populations of Acinetobacter can promptly respond to contamination by alkanes in mangrove sediments.

    PubMed

    Rocha, Lidianne L; Colares, Geórgia B; Angelim, Alysson L; Grangeiro, Thalles B; Melo, Vânia M M

    2013-11-15

    This study evaluated the potential of bacterial isolates from mangrove sediments to degrade hexadecane, an paraffin hydrocarbon that is a large constituent of diesel and automobile lubricants. From a total of 18 oil-degrading isolates obtained by an enrichment technique, four isolates showed a great potential to degrade hexadecane. The strain MSIC01, which was identified by 16S rRNA gene sequencing as Acinetobacter sp., showed the best performance in degrading this hydrocarbon, being capable of completely degrading 1% (v/v) hexadecane within 48 h without releasing biosurfactants. Its hydrophobic surface probably justifies its potential to degrade high concentrations of hexadecane. Thus, the sediments from the studied mangrove harbour bacterial communities that are able to use oil as a carbon source, which is a particularly interesting feature due to the risk of oil spills in coastal areas. Moreover, Acinetobacter sp. MSIC01 emerged as a promising candidate for applications in bioremediation of contaminated mangrove sediments.

  8. Meta-analysis of colistin for the treatment of Acinetobacter baumannii infection.

    PubMed

    Chen, Zhijin; Chen, Yu; Fang, Yaogao; Wang, Xiaotian; Chen, Yanqing; Qi, Qingsong; Huang, Fang; Xiao, Xungang

    2015-11-24

    Multidrug resistant among Acinetobacter baumannii infection is associated with a high mortality rate and limits the therapeutic options. The aim of this study was to assess the safety and efficacy of colistin monotherapy vs. other single antibiotic therapy AND colistin-based combination therapy (with other antibiotics) vs. colistin alone for the treatment of Acinetobacter baumannii infection. Online electronic database were searched for studies evaluating colistin with or without other antibiotics in treatment of patients with drug-resistant Acinetobacter baumannii infection. Totally, twelve studies met the inclusion criteria. For colistin-based combination therapy, six articles including 668 patients were included. Our results showed that the overall clinical response did not differ significantly between colistin-based combination therapy and monotherapy (OR = 1.37, 95% CI = 0.86-2.19, P = 0.18). This insignificance was also detected in ICU mortality, length of stay and nephrotoxicity (P > 0.05). However, the colistin-based combination therapy was shown increasing the microbiological response (OR = 2.14, 95% CI = 1.48-3.07, P < 0.0001). For colistin monotherapy, six studies involving 491 patients were analyzed. The results were in concordance with the findings of the colistin-based combination therapy group. Our results suggest that colistin may be a promising therapy as safe and efficacious as standard antibiotics for the treatment of drug-resistant Acinetobacter baumannii infection.

  9. Meta-analysis of colistin for the treatment of Acinetobacter baumannii infection

    PubMed Central

    Chen, Zhijin; Chen, Yu; Fang, Yaogao; Wang, Xiaotian; Chen, Yanqing; Qi, Qingsong; Huang, Fang; Xiao, Xungang

    2015-01-01

    Multidrug resistant among Acinetobacter baumannii infection is associated with a high mortality rate and limits the therapeutic options. The aim of this study was to assess the safety and efficacy of colistin monotherapy vs. other single antibiotic therapy AND colistin-based combination therapy (with other antibiotics) vs. colistin alone for the treatment of Acinetobacter baumannii infection. Online electronic database were searched for studies evaluating colistin with or without other antibiotics in treatment of patients with drug-resistant Acinetobacter baumannii infection. Totally, twelve studies met the inclusion criteria. For colistin-based combination therapy, six articles including 668 patients were included. Our results showed that the overall clinical response did not differ significantly between colistin-based combination therapy and monotherapy (OR = 1.37, 95% CI = 0.86–2.19, P = 0.18). This insignificance was also detected in ICU mortality, length of stay and nephrotoxicity (P > 0.05). However, the colistin-based combination therapy was shown increasing the microbiological response (OR = 2.14, 95% CI = 1.48–3.07, P < 0.0001). For colistin monotherapy, six studies involving 491 patients were analyzed. The results were in concordance with the findings of the colistin-based combination therapy group. Our results suggest that colistin may be a promising therapy as safe and efficacious as standard antibiotics for the treatment of drug-resistant Acinetobacter baumannii infection. PMID:26597507

  10. Phenotypic characterization of Acinetobacter baumannii isolates from intensive care units at a tertiary-care hospital in Egypt.

    PubMed

    Nageeb, W; Kamel, M; Zakaria, S; Metwally, L

    2014-04-03

    Multi-drug resistant (MDR) strains of Acinetobacter baumannii are responsible for an increasing number of opportunistic infections in hospitals. This study determined the prevalence of MDR A. baumannii isolates from intensive care units in a large tertiary-care hospital in Ismailia, Egypt, and the occurrence of different beta-lactamases in these isolates. Biotyping and antimicrobial susceptibility profile was done for isolated strains. Respiratory, urine, burn wound and blood specimens were collected from 350 patients admitted to different units; 10 strains (2.9%) of A. baumannii were isolated. All isolates showed resistance to more than 3 classes of antibiotics. Among the isolates, 6 isolates were carbapenemase producers, 2 were AmpC beta-lactamase producers and no isolates were metallo-beta-lactamase producers. Despite the low prevalence of A. baumannii infection in this hospital, the antibiotic resistance profile suggests that prevention of health-care-associated transmission of MDR Acinetobacter spp. infection is essential.

  11. Systematic Review of Antimicrobial Resistance of Clinical Acinetobacter baumannii Isolates in Iran: An Update.

    PubMed

    Razavi Nikoo, Hadi; Ardebili, Abdollah; Mardaneh, Jalal

    2017-09-01

    Treatment of Acinetobacter baumannii has become a medical challenge because of the increasing incidence of multiresistant strains and a lack of viable treatment alternatives. This systematic review attempts to investigate the changes in resistance of A. baumannii to different classes of antibiotics in Iran, with emphasis on the antimicrobial activity of polymyxin B (PMB) and colistin (COL). Biomedical databases were searched for English-published articles evaluating microbiological activity of various antimicrobial agents, including PMB and COL. Then, the available data were extracted and analyzed. Thirty-one studies, published from 2009 to 2015, were identified which contain data for 3,018 A. baumannii clinical isolates. With the exception of polymyxins and tigecycline (TIG), there was a high rate of resistance to various groups of antibiotics, including carbapenems. The minimum inhibitory concentration (MIC) ranges for PMB and COL on A. baumannii isolates tested were 0.12-64 μg/ml and 0.001-128 μg/ml, respectively. Polymyxins showed adequate activity with no significant trends in the resistance rate during most of the study period. The incidence of resistance to TIG was estimated low from 2% to 38.4% among the majority of A. baumannii. The present systematic review of the published literatures revealed that multidrug-resistant (including carbapenem-resistant) strains of A. baumannii have increased in Iran. In these circumstances, the older antibiotics, such as COL or PMB, preferably in combination with other antimicrobials (rifampicin, meropenem), could be considered as the therapeutic solution against the healthcare-associated infections. Designing rational dosage regimens for patients to maximize the antimicrobial activity and minimize the emergence and prevalence of resistance is recommended.

  12. Phylogenetic signal in phenotypic traits related to carbon source assimilation and chemical sensitivity in Acinetobacter species.

    PubMed

    Van Assche, Ado; Álvarez-Pérez, Sergio; de Breij, Anna; De Brabanter, Joseph; Willems, Kris A; Dijkshoorn, Lenie; Lievens, Bart

    2017-01-01

    A common belief is that the phylogeny of bacteria may reflect molecular functions and phenotypic characteristics, pointing towards phylogenetic conservatism of traits. Here, we tested this hypothesis for a large set of Acinetobacter strains. Members of the genus Acinetobacter are widespread in nature, demonstrate a high metabolic diversity and are resistant to several environmental stressors. Notably, some species are known to cause opportunistic human infections. A total of 133 strains belonging to 33 species with validly published names, two genomic species and species of an as-yet unknown taxonomic status were analyzed using the GENIII technology of Biolog, which allows high-throughput phenotyping. We estimated the strength and significance of the phylogenetic signal of each trait across phylogenetic reconstructions based on partial RNA polymerase subunit B (rpoB) and core genome sequences. Secondly, we tested whether phylogenetic distance was a good predictor of trait differentiation by Mantel test analysis. And finally, evolutionary model fitting was used to determine if the data for each phenotypic character was consistent with a phylogenetic or an essentially random model of trait distribution. Our data revealed that some key phenotypic traits related to substrate assimilation and chemical sensitivity are linked to the phylogenetic placement of Acinetobacter species. The strongest phylogenetic signals found were for utilization of different carbon sources such as some organic acids, amino acids and sugars, thus suggesting that in the diversification of Acinetobacter carbon source assimilation has had a relevant role. Future work should be aimed to clarify how such traits have shaped the remarkable ability of this bacterial group to dominate in a wide variety of habitats.

  13. Bactericidal activity of herbal volatile oil extracts against multidrug-resistant Acinetobacter baumannii

    PubMed Central

    Intorasoot, Amornrat; Chornchoem, Piyaorn; Sookkhee, Siriwoot; Intorasoot, Sorasak

    2017-01-01

    Aim: The aim of the study is to investigate the antibacterial activity of 10 volatile oils extracted from medicinal plants, including galangal (Alpinia galanga Linn.), ginger (Zingiber officinale), plai (Zingiber cassumunar Roxb.), lime (Citrus aurantifolia), kaffir lime (Citrus hystrix DC.), sweet basil (Ocimum basilicum Linn.), tree basil (Ocimum gratissimum), lemongrass (Cymbopogon citratus DC.), clove (Syzygium aromaticum), and cinnamon (Cinnamomum verum) against four standard strains of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, and 30 clinical isolates of multidrug-resistant A. baumannii (MDR-A. baumannii). Materials and Methods: Agar diffusion, minimum inhibitory concentration, and minimum bactericidal concentration (MBC) were employed for the determination of bactericidal activity of water distilled medicinal plants. Tea tree oil (Melaleuca alternifolia) was used as positive control in this study. Results: The results indicated the volatile oil extracted from cinnamon exhibited potent antibacterial activity against the most common human pathogens, S. aureus, E. coli, P. aeruginosa, and A. baumannii. Most of volatile oil extracts were less effective against non-fermentative bacteria, P. aeruginosa. In addition, volatile oil extracted from cinnamon, clove, and tree basil possessed potent bactericidal activity against MDR-A. baumannii with MBC90 of 0.5, 1, and 2 mg/mL, respectively. Conclusions: The volatile oil extracts would be useful as alternative natural product for the treatment of the most common human pathogens and MDR-A. baumannii infections. PMID:28512603

  14. Bactericidal activity of herbal volatile oil extracts against multidrug-resistant Acinetobacter baumannii.

    PubMed

    Intorasoot, Amornrat; Chornchoem, Piyaorn; Sookkhee, Siriwoot; Intorasoot, Sorasak

    2017-01-01

    The aim of the study is to investigate the antibacterial activity of 10 volatile oils extracted from medicinal plants, including galangal (Alpinia galanga Linn.), ginger (Zingiber officinale), plai (Zingiber cassumunar Roxb.), lime (Citrus aurantifolia), kaffir lime (Citrus hystrix DC.), sweet basil (Ocimum basilicum Linn.), tree basil (Ocimum gratissimum), lemongrass (Cymbopogon citratus DC.), clove (Syzygium aromaticum), and cinnamon (Cinnamomum verum) against four standard strains of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, and 30 clinical isolates of multidrug-resistant A. baumannii (MDR-A. baumannii). Agar diffusion, minimum inhibitory concentration, and minimum bactericidal concentration (MBC) were employed for the determination of bactericidal activity of water distilled medicinal plants. Tea tree oil (Melaleuca alternifolia) was used as positive control in this study. The results indicated the volatile oil extracted from cinnamon exhibited potent antibacterial activity against the most common human pathogens, S. aureus, E. coli, P. aeruginosa, and A. baumannii. Most of volatile oil extracts were less effective against non-fermentative bacteria, P. aeruginosa. In addition, volatile oil extracted from cinnamon, clove, and tree basil possessed potent bactericidal activity against MDR-A. baumannii with MBC90 of 0.5, 1, and 2 mg/mL, respectively. The volatile oil extracts would be useful as alternative natural product for the treatment of the most common human pathogens and MDR-A. baumannii infections.

  15. Characterization of the Acinetobacter baumannii growth phase-dependent and serum responsive transcriptomes.

    PubMed

    Jacobs, Anna C; Sayood, Khalid; Olmsted, Stephen B; Blanchard, Catlyn E; Hinrichs, Steven; Russell, David; Dunman, Paul M

    2012-04-01

    Acinetobacter baumannii has emerged as a bacterial pathogen of considerable healthcare concern. Yet, little is known about the organism's basic biological processes and the regulatory networks that modulate expression of its virulence factors and antibiotic resistance. Using Affymetrix GeneChips , we comprehensively defined and compared the transcriptomes of two A. baumannii strains, ATCC 17978 and 98-37-09, during exponential and stationary phase growth in Luria-Bertani (LB) medium. Results revealed that in addition to expected growth phase-associated metabolic changes, several putative virulence factors were dramatically regulated in a growth phase-dependent manner. Because a common feature between the two most severe types of A. baumannii infection, pneumonia and septicemia, includes the organism's dissemination to visceral organs via the circulatory system, microarray studies were expanded to define the expression properties of A. baumannii during growth in human serum. Growth in serum significantly upregulated iron acquisition systems, genes associated with epithelial cell adherence and DNA uptake, as well as numerous putative drug efflux pumps. Antibiotic susceptibility testing verified that the organism exhibits increased antibiotic tolerance when cultured in human serum, as compared to LB medium. Collectively, these studies provide researchers with a comprehensive database of A. baumannii's expression properties in LB medium and serum and identify biological processes that may contribute to the organism's virulence and antibiotic resistance.

  16. Active and Passive Immunization Protects against Lethal, Extreme Drug Resistant-Acinetobacter baumannii Infection

    PubMed Central

    Luo, Guanpingshen; Lin, Lin; Ibrahim, Ashraf S.; Baquir, Beverlie; Pantapalangkoor, Paul; Bonomo, Robert A.; Doi, Yohei; Adams, Mark D.; Russo, Thomas A.; Spellberg, Brad

    2012-01-01

    Extreme-drug-resistant (XDR) Acinetobacter baumannii is a rapidly emerging pathogen causing infections with unacceptably high mortality rates due to inadequate available treatment. New methods to prevent and treat such infections are a critical unmet medical need. To conduct a rational vaccine discovery program, OmpA was identified as the primary target of humoral immune response after intravenous infection by A. baumannii in mice. OmpA was >99% conserved at the amino acid level across clinical isolates harvested between 1951 and 2009 from cerebrospinal fluid, blood, lung, and wound infections, including carbapenem-resistant isolates, and was ≥89% conserved among other sequenced strains, but had minimal homology to the human proteome. Vaccination of diabetic mice with recombinant OmpA (rOmpA) with aluminum hydroxide adjuvant markedly improved survival and reduced tissue bacterial burden in mice infected intravenously. Vaccination induced high titers of anti-OmpA antibodies, the levels of which correlated with survival in mice. Passive transfer with immune sera recapitulated protection. Immune sera did not enhance complement-mediated killing but did enhance opsonophagocytic killing of A. baumannii. These results define active and passive immunization strategies to prevent and treat highly lethal, XDR A. baumannii infections. PMID:22253723

  17. Molecular mechanisms involved in the response to desiccation stress and persistence in Acinetobacter baumannii.

    PubMed

    Gayoso, Carmen M; Mateos, Jesús; Méndez, José A; Fernández-Puente, Patricia; Rumbo, Carlos; Tomás, María; Martínez de Ilarduya, Oskar; Bou, Germán

    2014-02-07

    Desiccation tolerance contributes to the maintenance of bacterial populations in hospital settings and may partly explain its propensity to cause outbreaks. Identification and relative quantitation of proteins involved in bacterial desiccation tolerance was made using label-free quantitation and iTRAQ labeling. Under desiccating conditions, the population of the Acinetobacter baumannii clinical strain AbH12O-A2 decreased in the first week, and thereafter, a stable population of 0.5% of the original population was maintained. Using label-free quantitation and iTRAQ labeling, 727 and 765 proteins, respectively, were detected; 584 of them by both methods. Proteins overexpressed under desiccation included membrane and periplasmic proteins. Proteins associated with antimicrobial resistance, efflux pumps, and quorum quenching were overexpressed in the samples subjected to desiccation stress. Electron microscopy revealed clear morphological differences between desiccated and control bacteria. We conclude that A. baumannii is able to survive long periods of desiccation through the presence of cells in a dormant state, via mechanisms affecting control of cell cycling, DNA coiling, transcriptional and translational regulation, protein stabilization, antimicrobial resistance, and toxin synthesis, and that a few surviving cells embedded in a biofilm matrix are able to resume growth and restore the original population in appropriate environmental conditions following a "bust-and-boom" strategy.

  18. Emergence and clonal dissemination of carbapenem-hydrolysing OXA-58-producing Acinetobacter baumannii isolates in Bolivia.

    PubMed

    Sevillano, Elena; Fernández, Elena; Bustamante, Zulema; Zabalaga, Silvia; Rosales, Ikerne; Umaran, Adelaida; Gallego, Lucía

    2012-01-01

    Acinetobacter baumannii is an emerging multidrug-resistant pathogen and very little information is available regarding its imipenem resistance in Latin American countries such as Bolivia. This study investigated the antimicrobial resistance profile of 46 clinical strains from different hospitals in Cochabamba, Bolivia, from March 2008 to July 2009, and the presence of carbapenemases as a mechanism of resistance to imipenem. Isolates were obtained from 46 patients (one isolate per patient; 30 males,16 females) with an age range of 1 day to 84 years, and were collected from different sample types, the majority from respiratory tract infections (17) and wounds (13). Resistance to imipenem was detected in 15 isolates collected from different hospitals of the city. These isolates grouped into the same genotype, named A, and were resistant to all antibiotics tested including imipenem, with susceptibility only to colistin. Experiments to detect carbapenemases revealed the presence of the OXA-58 carbapenemase. Further analysis revealed the location of the bla(OXA-58) gene on a 40 kb plasmid. To our knowledge, this is the first report of carbapenem resistance in A. baumannii isolates from Bolivia that is conferred by