Silva, Lívia Viganor da; Araújo, Manuela Tedesco; Santos, Kátia Regina Netto dos; Nunes, Ana Paula Ferreira
Methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative Staphylococcus spp (CNS) are the most common pathogens that cause serious long term infections in patients. Despite the existence of new antimicrobial agents, such as linezolid, vancomycin (VAN) remains the standard therapy for the treatment of infections caused by these multidrug-resistant strains. However, the use of VAN has been associated with a high frequency of therapeutic failures in some clinical scenarios, mainly with decreasing concentration of VAN. This work aims to evaluate the synergic potential of VAN plus sulfamethoxazole/trimethoprim (SXT), VAN plus rifampin (RIF) and VAN plus imipenem (IPM) in sub-minimum inhibitory concentrations against 22 clinical strains of MRSA and CNS. The checkerboard method showed synergism of VAN/RIF and VAN/SXT against two and three of the 22 strains, respectively. The combination of VAN with IPM showed synergistic effects against 21 out of 22 strains by the E-test method. Four strains were analyzed by the time-kill curve method and synergistic activity was observed with VAN/SXT, VAN/RIF and especially VAN/IPM in sub-inhibitory concentrations. It would be interesting to determine if synergy occurs in vivo. Evidence of in vivo synergy could lead to a reduction of the standard VAN dosage or treatment time.
Miranda-Novales, Guadalupe; Leaños-Miranda, Blanca E; Vilchis-Pérez, Mariano; Solórzano-Santos, Fortino
Background combinations of drugs has been proposed as an alternative for oxacillin-resistant staphylococci infections, however, limited information about in vitro combinations are available for multi-resistant strains. The objective of this study was to describe the interaction of beta-lactams in combination with vancomycin or amikacin against 26 oxacillin and amikacin-resistant nosocomial Staphylococcus spp. isolates. Methods activity of dicloxacillin plus amikacin, cephalothin plus amikacin, cephalothin plus vancomycin, imipenem plus vancomycin and vancomycin plus amikacin was evaluated by checkerboard synergy tests and the fractional inhibitory concentration index (FIC) was calculated. Results: dicloxacillin plus amikacin, and cephalothin plus amikacin were synergistic or partially synergistic in 84.6% and 100% respectively. For nearly half of the isolates the mean concentrations of dicloxacillin, cephalothin and amikacin at which FIC indexes were calculated were achievable therapeutically. Vancomycin plus amikacin had synergistic effect only against two isolates, and partially synergistic in 38.6%. For the combinations vancomycin plus cephalothin and vancomycin plus imipenem the effect was additive in 76.9% and 80.7% respectively. Conclusion in this study the checkerboard analysis showed that amikacin in combination with cephalothin or dicloxacillin was synergistic against most of the resistant strains of S. aureus and coagulase-negative Staphylococcus. Vancomycin in combination with a beta-lactam (cephalothin or imipenem) showed additivity. An indifferent effect predominated for the combination vancomycin plus amikacin. Even though a synergistic effect is expected when using a beta-lactam plus amikacin combination, it is possible that the effect cannot be clinically achievable. Careful selection of antimicrobial combinations and initial MICs are mandatory for future evaluations. PMID:17034644
Svec, Pavel; Pantůček, Roman; Petráš, Petr; Sedláček, Ivo; Nováková, Dana
A group of 212 type and reference strains deposited in the Czech Collection of Microorganisms (Brno, Czech Republic) and covering 41 Staphylococcus species comprising 21 subspecies was characterised using rep-PCR fingerprinting with the (GTG)₅ primer in order to evaluate this method for identification of staphylococci. All strains were typeable using the (GTG)₅ primer and generated PCR products ranging from 200 to 4500 bp. Numerical analysis of the obtained fingerprints revealed (sub)species-specific clustering corresponding with the taxonomic position of analysed strains. Taxonomic position of selected strains representing the (sub)species that were distributed over multiple rep-PCR clusters was verified and confirmed by the partial rpoB gene sequencing. Staphylococcus caprae, Staphylococcus equorum, Staphylococcus sciuri, Staphylococcus piscifermentans, Staphylococcus xylosus, and Staphylococcus saprophyticus revealed heterogeneous fingerprints and each (sub)species was distributed over several clusters. However, representatives of the remaining Staphylococcus spp. were clearly separated in single (sub)species-specific clusters. These results showed rep-PCR with the (GTG)₅ primer as a fast and reliable method applicable for differentiation and straightforward identification of majority of Staphylococcus spp.
Liu, Xiao-Qin; Wang, Jing; Li, Wei; Zhao, Li-Qing; Lu, Yan; Liu, Jian-Hua; Zeng, Zhen-Ling
The multi-resistance gene cfr is widely distributed among various gram-positive and gram-negative species in livestock in China. To better understand the epidemiology of cfr among Staphylococcus spp. and E. coli isolates, 254 Staphylococcus spp. and 398 E. coli strains collected from six swine farms in China were subjected to prevalence and genetic analysis. Forty (15.7%) Staphylococcus spp. isolates, including 38 Staphylococcus sciuri strains, one Staphylococcus chromogenes strain, and one Staphylococcus lentus strain, and two (0.5%) E. coli isolates were found to contain the cfr gene. Most of the 38 S. sciuri strains were clonally unrelated; however, clonal dissemination of cfr-positive S. sciuri was detected at the same farm. In eight randomly selected cfr-positive staphylococci, a cfr-harboring module (IS21-558-cfr-ΔtnpB) was detected in six S. sciuri isolates; cfr was bracketed by two copies of ISEnfa4 or IS256 in the remaining two S. sciuri isolates. In the two E. coli isolates, EP25 and EP28, cfr was flanked by two IS26 elements in the same or opposite orientation, respectively. Complete sequence analysis of the novel F43:A-:B- plasmid pHNEP28 revealed that it contains two multi-resistance regions: cfr together with floR, qnrS1 interspersed with IS26, ΔISCR2 and ISKpn19, and blaTEM-1 together with tet(M) interspersed with IS26, ISApl1, ΔTn2, and ΔIS1B. The coexistence of cfr with other resistance genes on a conjugative plasmid may contribute to the dissemination of these genes by co-selection. Thus, rational drug use and continued surveillance of cfr in swine farms are warranted. PMID:28293235
Brackman, Gilles; Coenye, Tom
The Gram-positive, facultative anaerobic coccus-shaped bacteria of the genus Staphylococcus are among the most important causative agents of acute and chronic bacterial infections in humans as well as in animals. Treatment of Staphylococcus infections has become increasingly challenging due to the growing problem of antibiotic resistance. For this reason innovative antimicrobials with novel targets and modes of action are needed. Since the discovery that QS is used by Staphylococcus spp. to coordinate the expression of several genes involved in virulence, biofilm formation and pathogenicity, QS inhibition has gained increasing attention as an alternative anti-pathogenic strategy. A major advantage compared with antibiotic therapy is that QSIs are used in concentrations that do not affect bacterial growth. For this reason, it is expected that these compounds would exert less pressure towards the development of resistance. However, some important points still need to be addressed. Although several inhibitors have proven to be active antipathogenic agents in vitro and in several in vivo models, it is still unknown whether these compounds will also be useful in humans. Furthermore, several fundamental mechanisms by which the different QS systems in Staphylococcus spp. exert their regulatory functions and how they are inhibited by QSIs are still poorly understood. In order to achieve real-life applications with QSIs, these challenges should be addressed and more research will be needed. In this article, we will discuss the different QS systems present in Staphylococcus spp., how they are used to control virulence and biofilm formation and how they can be blocked.
El-Sharoud, Walid M; Spano, Giuseppe
A total of 87 samples of fresh and stored Domiati cheese (an Egyptian soft cheese) were examined for the presence of Staphylococcus spp. Fifteen Staphylococcus isolates identified as S. aureus (2 isolates), S. xylosus (4), S. caprae (4), and S. chromogenes (5) were recovered from 15 cheese samples. The S. aureus isolates were resistant to penicillin G and ampicillin, and one isolate was also resistant to tetracycline. S. aureus isolates harbored classical staphylococcal enterotoxin (SE) genes (sea and seb) and recently characterized SE-like genes (selg, seli, selm, and selo). One S. aureus isolate contained a single SE gene (sea), whereas another isolate contained five SE genes (seb, selg, seli, selm, and selo). These results suggest that Domiati cheese is a source for various Staphylococcus species, including S. aureus strains that could be enterotoxigenic.
Furuhata, Katsunori; Ishizaki, Naoto; Sogawa, Kazuyuki; Kawakami, Yasushi; Lee, Shin-Ichi; Sato, Masahiro; Fukuyama, Masafumi
From May 2014 to February 2015, 319 university students (male, n=173; female n=146) of 18 to 24 years of age who carried mobile phones or computer tablets were selected as subjects. Staphylococcus spp. were detected in 101 of 319 samples (31.7%). In the present study, 11 strains of S. aureus were isolated and identified, not all of which were methicillin-resistant Staphylococcus aureus (MRSA). Overall, 14 species were identified, with 11 strains (10.9%) of S. xylosus being isolated at the highest frequency. Following this were eight strains (7.9%) of S. cohnii and seven strains (6.9%) each of S. capitis and S. haemolyticus. Staphylococcus spp. isolation was performed with bacterial samples obtained from the mobile phones of 22 specific subjects (males, n=12; females, n=10). Staphylococcus spp. isolation was performed on days -1, 7 and 30 of the experiment. Staphylococcus spp. were positively detected one or more times in 12 subjects (54.5%). In one subject (8.3%), all three tests were positive. Furthermore, two tests were positive in three (25.0%). In the eight remaining subjects (66.7%) Staphylococcus spp. were detected only once. For the three abovementioned tests, we investigated the pulsed-field gel electrophoresis (PFGE) patterns of the strains derived from the mobile phone and from the fingers of three subjects in whom the same bacterial species were isolated twice. From the cases with similarities between strains derived from the fingers and the mobile phones and cases, with consistency in the strains derived from the mobile phone at different times, commonality was observed in the strains derived from the fingers and mobile phones along with chronological uniformity in the strains derived from the mobile phones. A total of 101 Staphylococcus spp. strains were isolated from mobile phones. According to drug susceptibility tests, 99 strains (98.0%) were found to have some degree of resistance to drugs (excluding one strain each of S. aureus and S. haemolyticus
Slany, Michal; Vanerkova, Martina; Nemcova, Eva; Zaloudikova, Barbora; Ruzicka, Filip; Freiberger, Tomas
High-resolution melting analysis (HRMA) is a fast (post-PCR) high-throughput method to scan for sequence variations in a target gene. The aim of this study was to test the potential of HRMA to distinguish particular bacterial species of the Staphylococcus genus even when using a broad-range PCR within the 16S rRNA gene where sequence differences are minimal. Genomic DNA samples isolated from 12 reference staphylococcal strains (Staphylococcus aureus, Staphylococcus capitis, Staphylococcus caprae, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus intermedius, Staphylococcus saprophyticus, Staphylococcus sciuri, Staphylococcus simulans, Staphylococcus warneri, and Staphylococcus xylosus) were subjected to a real-time PCR amplification of the 16S rRNA gene in the presence of fluorescent dye EvaGreen™, followed by HRMA. Melting profiles were used as molecular fingerprints for bacterial species differentiation. HRMA of S. saprophyticus and S. xylosus resulted in undistinguishable profiles because of their identical sequences in the analyzed 16S rRNA region. The remaining reference strains were fully differentiated either directly or via high-resolution plots obtained by heteroduplex formation between coamplified PCR products of the tested staphylococcal strain and phylogenetically unrelated strain.
Yugueros, Javier; Temprano, Alejandro; Sánchez, María; Luengo, José María; Naharro, Germán
Oligonucleotide primers specific for the Staphylococcus aureus gap gene were previously designed to identify 12 Staphylococcus spp. by PCR. In the present study, AluI digestion of PCR-generated products rendered distinctive restriction fragment length polymorphism patterns that allowed 24 Staphylococcus spp. to be identified with high specificity. PMID:11574593
Pieri, Fabio A; Vargas, Taise F; Galvão, Newton N; Nogueira, Paulo A; Orlandi, Patrícia P
The aim of this study was to characterize and compare Staphylococcus spp. isolated from hospitalized patients and beef marketed in the city of Porto Velho-RO, Brazil. The isolates were subjected to antibiogram tests, adherence capacity tests, detection of the mecA gene, and epidemiological investigation by the random amplified polymorphic DNA (RAPD) technique, using the primers M13 and H12. Among the 123 Staphylococcus spp. isolates, 50 were identified as S. aureus and 73 as coagulase-negative Staphylococcus; among the latter, 7 species were identified. It was observed that the coagulase-negative Staphylococcus isolates showed greater adhesion ability than S. aureus. The profile of antimicrobial susceptibility was different among isolates, all of which were susceptible to vancomycin and linezolid, and had high penicillin resistance rates, varying according to the bacterial class and the source. In this study, all strains were negative for mecA gene detection; however, 36% of S. aureus and 17% of coagulase-negative Staphylococcus were resistant to oxacillin. The genetic relationship of these bacteria, analyzed by RAPD, was able to discriminate the species of coagulase-negative Staphylococcus strains of S. aureus along its origin. It was concluded that the isolates of Staphylococcus spp. derived from beef and human infections differ genetically. Thus, it is suggested that isolates from beef, which were grouped within hospital isolates, were probably carried via contact with beef in hospital professionals or patients.
Tan, Chao; Wang, Jun; Hu, Yifang; Wang, Peng; Zou, Lili
Staphylococcus aureus and Staphylococcus epidermidis are two of the most significant opportunistic human pathogens, causing medical implant and nosocomial infections worldwide. These bacteria contain surface proteins that play crucial roles in multiple biological processes. It has become apparent that they have evolved a number of unique mechanisms by which they can immobilise proteins on their surface. Notably, a conserved cell membrane-anchored enzyme, sortase A (SrtA), can catalyse the covalent attachment of precursor bacterial cell wall-attached proteins to peptidoglycan. Considering its indispensable role in anchoring substrates to the cell wall and its effects on virulence, SrtA has attracted great attention. In this study, a 549-bp gene was cloned from a pathogenic S. epidermidis strain, YC-1, which shared high identity with srtA from other Staphylococcus spp. A mutant strain, YC-1ΔsrtA, was then constructed by allelic exchange mutagenesis. The direct survival rate assay suggested that YC-1ΔsrtA had a lower survival capacity in healthy mice blood compare with the wild-type strain, indicating that the deletion of srtA affects the virulence and infectious capacity of S. epidermidis YC-1. YC-1ΔsrtA was then administered via intraperitoneal injection and it provided a relative percent survival value of 72.7 % in mice against S. aureus TC-1 challenge. These findings demonstrate the possbility that YC-1ΔsrtA might be used as a live attenuated vaccine to produce cross-protection against S. aureus.
Switalski, L M; Rydén, C; Rubin, K; Ljungh, A; Höök, M; Wadström, T
Fibronectin, a major protein component of plasma and loose connective tissue has previously been shown to bind to several strains of Staphylococcus aureus. We examined a large number of strains of different species of Staphylococcus with respect to their ability to bind fibronectin. The relative numbers of strains defined as fibronectin-binders among the different species were as follows: S. aureus (22 of 23), S. haemolyticus (5 of 5), S. warneri (8 of 11), S. hyicus (5 of 6), S. hominis (13 of 17), S. saprophyticus (11 of 20), S. epidermidis (4 of 7), and S. simulans (8 of 10). Only three species showed a predominance of nonbinders over binders: S. capitis (4 of 14), S. xylosus (0 of 4), and S. cohnii (3 of 11). These data indicate that staphylococcal species isolated from soft tissue infections frequently have the ability to bind fibronectin and suggest that the ability to bind to this protein may contribute to the virulence of coagulase-positive and coagulase-negative staphylococci. PMID:6315582
Jang, Yunho; Bae, Dong hwa; Cho, Jae-Keun; Bahk, Gyung Jin; Lim, Suk-Kyung; Lee, Young Ju
Staphylococci were isolated from dogs in animal hospitals, animal shelters, and the Daegu PET EXPO to investigate the characteristics of circulating methicillin-resistant Staphylococcal (MRS) strains in companion animals in Korea. A total of 36/157 isolates were classified as MRS, and subdivided as follows: 1 methicillin-resistant Staphylococcus aureus (MRSA), 4 methicillin-resistant Staphylococcus epidermidis, 2 methicillin-resistant Staphylococcus haemolyticus, and 29 MRS spp. Among the 36 MRS isolates tested, 100% were resistant to oxacillin and penicillin, and at least 50% were resistant to sulfamethoxazole/trimethoprim (69.4%), erythromycin (63.9%), tetracycline (58.3%), cefoxitin (55.6%), clindamycin (50.0%) or pirlimycin (50.0%). Additionally, 34/36 MRS isolates (94.4%) were mecA positive, 15 of which were further classified as SCCmec type V, 6 isolates as type I, 4 isolates as type IIIb, 1 isolate as type IVa, 1 isolate as type IV, with 7 isolates being non-classifiable. The results of multilocus sequence typing and spa typing for the one MRSA strain were ST 72 (1-4-1-8-4-4-3) and spa t148. Our results provide evidence that companion animals like dogs may be MRS carriers, and that continued surveillance of MRS in companion animals is required to prevent increased incidences in humans.
de Melo, Dayanne Araújo; Coelho, Irene da Silva; da Motta, Cássia Couto; Rojas, Anna Carolina Coelho Marín; Dubenczuk, Felipe Carlos; Coelho, Shana de Mattos de Oliveira; de Souza, Miliane Moreira Soares
Staphylococcus aureus antimicrobial resistance, especially to beta-lactams, favors treatment failures and its persistence in herd environment. This work aimed to develop a more specific primer for mecA gene detection based on the comparison of the conserved regions from distinct host origins and also investigated the presence of homologue mecALGA251 in bovine strains. A total of 43 Staphylococcus spp. were included in this study, comprising 38 bovine S. aureus, two human and three equine coagulase-negative staphylococci (CNS). Phenotypical methicillin-resistance detection was performed through oxacillin agar-screening and cefoxitin disk-diffusion test. None isolate tested positive for mecALGA251 gene. For mecA gene PCR, new primers were designed based on the sequences of human S. aureus (HE681097) and bovine S. sciuri (AY820253) mecA. The new primers based on the S. aureus mecA sequence amplified fragments of human and equine CNS and the ones based on S. sciuri mecA sequence only yielded fragments for S. aureus bovine strains. Multiples alignments of mecA gene sequences from bovine, human and equine revealed punctual but significant differences in bovine strains that can lead to the mecA gene detection impairment. The observed divergences of mecA gene sequences are not a matter of animal or human origin, it is a specificity of bovine samples. PMID:25477945
da Silva, Sabina Dos Santos Paulino; Cidral, Thiago André; Soares, Maria José dos Santos; de Melo, Maria Celeste Nunes
Food handlers carrying enterotoxin-producing Staphylococcus are a potential source of food poisoning. The aim of this study was to analyze genes encoding enterotoxins in coagulase-positive Staphylococcus (CoPS) and coagulase-negative Staphylococcus (CoNS) isolated from the anterior nostrils and hands of food handlers at a university restaurant in the city of Natal, Northeast Brazil. Thirty food handlers were screened for the study. The isolates were subjected to Gram staining, a bacitracin sensitivity test, mannitol fermentation, and catalase and coagulase tests. CoNS and CoPS strains were subsequently identified by a Vitek 2 System (BioMerieux, France) and various biochemical tests. Polymerase chain reaction was used to detect genes for enterotoxins A, B, C, D, E, G, H, and I (sea, seb, sec, sed, see, seg, seh, and sei) and a disc-diffusion method was used to determine susceptibility to several classes of antimicrobials. All food handlers presented staphylococci on their hands and/or noses. The study found 58 Staphylococcus spp., of which 20.7% were CoPS and 79.3% were CoNS. S. epidermidis was the most prevalent species. Twenty-nine staphylococci (50%) were positive for one or more enterotoxin genes, and the most prevalent genes were seg and sei, each with a frequency of 29.3%. Indeed, CoNS encoded a high percentage of enterotoxin genes (43.5%). However, S. aureus encoded even more enterotoxin genes (75%). Most isolates showed sensitivity to the antibiotics used for testing, except for penicillin (only 35% sensitive). The results from this study reinforce that coagulase-negative as well as coagulase-positive staphylococci isolated from food handlers are capable of genotypic enterotoxigenicity.
STAPHYLOCOCCUS AUREUS , CHROMOSOMES), (*CHROMOSOMES, MAPPING), NITROSO COMPOUNDS, GUANIDINES, GENETICS, MUTATIONS, DRUGS, TOLERANCES(PHYSIOLOGY), TEST METHODS, DEOXYRIBONUCLEIC ACIDS, INHIBITION, RESISTANCE(BIOLOGY).
Eryılmaz, Müjde; Akın, Ahmet; Arıkan Akan, Ozay
Nosocomial infections which exhibit an increasing trend worldwide, are important contributors to morbidity and mortality. Most bacteria that cause nosocomial infections can retain their viability even after exposure to disinfectants in routine practice. This study was conducted to determine the susceptibilities of nosocomial Staphylococcus aureus and Enterococcus spp. isolates to various disinfectants. A total of 30 S.aureus [16 were methicillin-resistant (MRSA), 14 were methicillin-susceptible (MSSA)] and 21 Enterococcus spp. (13 E.faecalis, 7 E.faecium, 1 non-typable Enterococcus spp.) strains isolated from clinical samples of hospitalized patients as nosocomial infection agents in the Central Microbiology Laboratory of Ibn-i Sina Hospital, Ankara University, Faculty of Medicine, were included in the study. Glutaraldehyde (2% wt/vol), chlorhexidine gluconate (4% wt/vol), 2-propanol (70% vol/vol), povidone iodine (7.5% wt/vol), povidone iodine (10% wt/vol) and hydrogen peroxide (3% wt/vol) susceptibilities of the isolates were investigated by quantitative suspension test at contact times of 3, 5, and 10 minutes. All of the isolates were found susceptible to glutaraldehyde (2%), chlorhexidine gluconate (4%), povidone iodine (7.5%), povidone iodine (10%) and 2-propanol (70%) at all tested contact times. However, 12 S.aureus (5 MSSA, 7 MRSA) and 3 enterococci (2 E.faecium, 1 E.faecalis) isolates were found susceptible to hydrogen peroxide (3%) at 3 minutes contact time; 11 S.aureus (4 MSSA, 7 MRSA) and 7 E.faecalis isolates were found susceptible at 5 minutes contact time, and 6 S.aureus (4 MSSA, 2 MRSA) and 3 enterococci (1 E.faecium, 2 E.faecalis) isolates were found susceptible at 10 minutes contact time. One MSSA and 8 enterococci (4 E.faecium, 3 E.faecalis, 1 Enterococcus spp.) isolates were found resistant to hydrogen peroxide (3%) at 10 minutes contact time. In conclusion, glutaraldehyde (2%), chlorhexidine gluconate (4%), povidone iodine (7.5%), povidone
Guimarães César, Josi; Madruga Peres, Andriele; Pereira das Neves, Caroline; Tupiniquim Freitas de Abreu, Érica; Fagundes de Mello, Jozi; Nunes Moreira, Ângela; Lameiro Rodrigues, Kelly
Introducción: la procura por estabelecimientos que ofrecen alimentos prontos para consumo ha aumentado, sin embrago, los alimentos disponibles en estos locales pueden estar contaminados con microorganismos patogénicos, pudiendo causar enfermedades transmitidas por alimentos. Objetivos: evaluar la calidad microbiológica de las ensaladas de lechuga en los restaurantes de Pelotas RS Brasil, a través de los recuentos de coliformes termotolerantes, Escherichia coli, Staphylococcus spp. y la detección de Salmonella spp. Resistencia a los antimicrobianos de Staphylococcus spp. también se evalúan. Métodos: fueron colectadas 36 muestras de ensaladas de lechuga en nueve restaurantes y realizada la cuantificación de coliformes termotolerantes, Escherichia coli y Staphylococcus spp. e investigación de Salmonella spp., siguiendo la metodología del Bacteriological Analytical Manual. Los aislados de Staphylococcus spp. fueron sometidos al examen de resistencia a antimicrobianos por el método de difusión con discos. Resultados y discusión: de las 36 muestras de ensalada de lechuga, 61,1% presentaron cuantificación de coliformes termotolerantes superiores a lo permitido por la legislación brasileña, y hubo confirmación de E. coli en 5,6% de las muestras. La cuantificación de Staphylococcus coagulasa positiva representó 5,6% de los aislados y Staphylococcus coagulasa negativa representó 77,8%. Todas las muestras presentaron ausencia de Salmonella spp. De los 30 aislados de Staphylococcus spp. examinados, 56,7% fueron resistentes a penicilina, 46,7% a oxacilina, 26,7% a eritromicina y 23,3% fueron multirresistentes. Conclusión: la calidad microbiológica de las ensaladas de lechuga se mostró inadecuada debido a la presencia de microorganismos patogénicos, y los aislados de Staphylococcus spp. presentaron elevado porcentaje de resistencia antimicrobiana.
Parker, Dane; Narechania, Apurva; Sebra, Robert; Deikus, Gintaras; Larussa, Samuel; Ryan, Chanelle; Smith, Hannah; Prince, Alice; Mathema, Barun; Ratner, Adam J; Kreiswirth, Barry; Planet, Paul J
Staphylococcus aureus 502A was a strain used in bacterial interference programs during the 1960s and early 1970s. Infants were deliberately colonized with 502A with the goal of preventing colonization with more invasive strains. We present the completed genome sequence of this organism.
Amako, K; Umeda, A; Murata, K
The arrangement of peptidoglycan in the cell wall of Staphylococcus was observed with the newly developed freeze-fracture technique, using n-octanol instead of water as the freezing medium. The replica of the trichloroacetic acid-extracted cell wall (TCA-wall) showed two areas. One of them has a concentric circular structure, a characteristic surface structure of the staphylococcal cell wall, and the other showed an irregular and rough surface. The chemical analysis of the wall revealed that the TCA-wall consisted of mostly peptidoglycan. By digesting the TCA-wall with lysozyme, the circular structures were greatly disturbed, and they disappeared after 60 min of treatment. From these observations it can be expected that the peptidoglycan is arranged in a concentric circular manner in the newly generated cell wall of Staphylococcus. Images PMID:7068534
Abouelkhair, Mohamed A.; Riley, Matthew C.; Bemis, David A.
ABSTRACT We report the first complete genome sequence of LMG 22219 (=ON 86T = CCUG 49543T), the Staphylococcus pseudintermedius type strain isolated from feline lung tissue. This sequence information will facilitate phylogenetic comparisons of staphylococcal species and other bacteria at the genome level. PMID:28209834
Balachandran, Manasi; Riley, Matthew C.; Bemis, David A.
ABSTRACT Here, we report the first complete genome sequence of the Staphylococcus aureus strain Wood 46. Wood 46 has played an important role in understanding the virulence and pathogenesis of S. aureus infections. This report will assist efforts in vaccine development against methicillin-resistant S. aureus (MRSA) infections. PMID:28360163
Abouelkhair, Mohamed A; Riley, Matthew C; Bemis, David A; Kania, Stephen A
We report the first complete genome sequence of LMG 22219 (=ON 86(T) = CCUG 49543(T)), the Staphylococcus pseudintermedius type strain isolated from feline lung tissue. This sequence information will facilitate phylogenetic comparisons of staphylococcal species and other bacteria at the genome level.
Balachandran, Manasi; Riley, Matthew C; Bemis, David A; Kania, Stephen A
Here, we report the first complete genome sequence of the Staphylococcus aureus strain Wood 46. Wood 46 has played an important role in understanding the virulence and pathogenesis of S. aureus infections. This report will assist efforts in vaccine development against methicillin-resistant S. aureus (MRSA) infections.
Yugueros, Javier; Temprano, Alejandro; Berzal, Beatriz; Sánchez, María; Hernanz, Carmen; Luengo, José María; Naharro, Germán
The gap gene of Staphylococcus aureus, encoding glyceraldehyde-3-phosphate dehydrogenase, was used as a target to amplify a 933-bp DNA fragment by PCR with a pair of primers 26 and 25 nucleotides in length. PCR products, detected by agarose gel electrophoresis, were also amplified from 12 Staphylococcus spp. analyzed previously. Hybridization with an internal 279-bp DNA fragment probe was positive in all PCR-positive samples. No PCR products were amplified when other gram-positive and gram-negative bacterial genera were analyzed using the same pair of primers. AluI digestion of PCR-generated products gave 12 different restriction fragment length polymorphism (RFLP) patterns, one for each species analyzed. However, we could detect two intraspecies RFLP patterns in Staphylococcus epidermidis, Staphylococcus hominis, and Staphylococcus simulans which were different from the other species. An identical RFLP pattern was observed for 112 S. aureus isolates from humans, cows, and sheep. The sensitivity of the PCR assays was very high, with a detection limit for S. aureus cells of 20 CFU when cells were suspended in saline. PCR amplification of the gap gene has the potential for rapid identification of at least 12 species belonging to the genus Staphylococcus, as it is highly specific. PMID:11101563
Yugueros, J; Temprano, A; Berzal, B; Sánchez, M; Hernanz, C; Luengo, J M; Naharro, G
The gap gene of Staphylococcus aureus, encoding glyceraldehyde-3-phosphate dehydrogenase, was used as a target to amplify a 933-bp DNA fragment by PCR with a pair of primers 26 and 25 nucleotides in length. PCR products, detected by agarose gel electrophoresis, were also amplified from 12 Staphylococcus spp. analyzed previously. Hybridization with an internal 279-bp DNA fragment probe was positive in all PCR-positive samples. No PCR products were amplified when other gram-positive and gram-negative bacterial genera were analyzed using the same pair of primers. AluI digestion of PCR-generated products gave 12 different restriction fragment length polymorphism (RFLP) patterns, one for each species analyzed. However, we could detect two intraspecies RFLP patterns in Staphylococcus epidermidis, Staphylococcus hominis, and Staphylococcus simulans which were different from the other species. An identical RFLP pattern was observed for 112 S. aureus isolates from humans, cows, and sheep. The sensitivity of the PCR assays was very high, with a detection limit for S. aureus cells of 20 CFU when cells were suspended in saline. PCR amplification of the gap gene has the potential for rapid identification of at least 12 species belonging to the genus Staphylococcus, as it is highly specific.
Salaberry, Sandra Renata Sampaio; Saidenberg, André Becker Simões; Zuniga, Eveline; Melville, Priscilla Anne; Santos, Franklin Gerônimo Bispo; Guimarães, Ednaldo Carvalho; Gregori, Fábio; Benites, Nilson Roberti
The aim of this study was to investigate genes involved in adhesion expression, biofilm formation, and enterotoxin production in isolates of Staphylococcus spp. from goats with subclinical mastitis and associate these results with the staphylococcal species. One hundred and twenty-four isolates were identified and polymerase chain reaction (PCR) was performed to detect the following genes: cna, ebpS, eno, fib, fnbA, fnbB, bap, sea, seb, sec, sed and see. The most commonly Staphylococcus species included S. epidermidis, S. lugdunensis, S. chromogenes, S. capitis ss capitis and S. intermedius. With the exception of fnbB, the genes were detected in different frequencies of occurrence in 86.3% of the Staphylococcus spp. isolates. Eno (73.2%) and bap (94.8%) were more frequently detected in coagulase-negative staphylococci (CNS); ebpS (76%), fib (90.9%) and fnbA (87%) were the most frequent genes in coagulase-positive staphylococci (CPS). Regarding enterotoxins, genes sed (28.2%) and see (24.2%) had a higher frequency of occurrence; sec gene was more frequently detected in CPS (58.8%). There was no association between the presence of the genes and the Staphylococcus species. Different virulence factors genes can be detected in caprine subclinical mastitis caused by CNS and CPS. The knowledge of the occurrence of these virulence factors is important for the development of effective control and prevention measures of subclinical mastitis caused by CNS and CPS in goats.
Chessa, Daniela; Ganau, Giulia; Spiga, Luisella; Bulla, Antonio; Mazzarello, Vittorio; Campus, Gian Vittorio; Rubino, Salvatore
Staphylococcus epidermidis and Staphylococcus aureus are currently considered two of the most important pathogens in nosocomial infections associated with catheters and other medical implants and are also the main contaminants of medical instruments. However because these species of Staphylococcus are part of the normal bacterial flora of human skin and mucosal surfaces, it is difficult to discern when a microbial isolate is the cause of infection or is detected on samples as a consequence of contamination. Rapid identification of invasive strains of Staphylococcus infections is crucial for correctly diagnosing and treating infections. The aim of the present study was to identify specific genes to distinguish between invasive and contaminating S. epidermidis and S. aureus strains isolated on medical devices; the majority of our samples were collected from breast prostheses. As a first step, we compared the adhesion ability of these samples with their efficacy in forming biofilms; second, we explored whether it is possible to determine if isolated pathogens were more virulent compared with international controls. In addition, this work may provide additional information on these pathogens, which are traditionally considered harmful bacteria in humans, and may increase our knowledge of virulence factors for these types of infections. PMID:26811915
Ertas Onmaz, Nurhan; Abay, Secil; Karadal, Fulden; Hizlisoy, Harun; Telli, Nihat; Al, Serhat
The aims of this study were to investigate the presence of Staphylococcus aureus and staphylococcal enterotoxins, as well as Salmonella spp. and to determine the antimicrobial susceptibilities of the isolates from fish samples. A total of 100 fish samples were analysed consisting of 30 anchovy, 35 trout and 35 sea bream. The presence of SEs was detected using ELISA and its genes confirmed by mPCR. Also, S. aureus and Salmonella spp. were detected in 9 (9%) and 5 (5%) samples, respectively. None of the S. aureus isolates had SEs and SEs genes. The resistance rates of the S. aureus isolates to erythromycin, tetracycline, and penicillin G were found to be 33% while Salmonella spp. isolates were resistant to trimethoprim-sulfamethoxazole, gentamicin and neomycine in 20%, 20% and 80%, respectively of the samples. It is of utmost important for public health that retail fish markets need to use hygienic practices in handling and processing operations.
Lundqvist, G.R.; Aalykke, C.; Bonde, G.J. )
Emissions of viable particles from a group of children were measured under controlled conditions in a climate chamber that simulated indoor environmental exposure in day-care institutions with tight building envelopes and outdoor air supply by natural infiltration only. Bioaerosol sampling was simultaneously applied with slit samplers and sediment plates. A total of 142 strains was identified. Most of these were from sediment plates (95%) as the colonies on the slit sampler were more crowded and too confluent for separation. On sediment plates, coryneform bacteria dominated (27-85%), followed in frequency by micrococci (4-50%), Staphylococcus epidermidis and saprophyticus (12-43%), Bacillus spp., most frequently B. megaterium (12-33%), and Acinetobacter spp. (11-14%). From the slit sampler plates, staphylococci dominated (67%), followed by coryneform species and micrococci (17%). Within the first hour after the group left the chamber, the number of colony forming units (CFU) suspended in the air decreased, corresponding to an equivalent dilution ventilation rate of 2.0 ACH (air changes per hour) for bacteria and 1.7 ACH for mold spores due to the catching of particles on surfaces and to die away of viable microorganisms. Accordingly, microbial surface contamination revealed an increase at the same time.
Bobenchik, April M; Hindler, Janet A; Giltner, Carmen L; Saeki, Sandra; Humphries, Romney M
Vitek 2 (bioMérieux, Inc., Durham, NC) is a widely used commercial antimicrobial susceptibility testing system. We compared MIC results obtained by Vitek 2 to those obtained by the Clinical and Laboratory Standards Institute (CLSI) broth microdilution (BMD) reference method for 134 staphylococcal and 84 enterococcal clinical isolates. Nineteen agents were evaluated, including all those available on Vitek 2 for testing staphylococci and enterococci. The resistance phenotypes tested included methicillin-resistant Staphylococcus aureus (MRSA) (n = 58), S. aureus with inducible clindamycin resistance (ICR) (n = 30), trimethoprim-sulfamethoxazole-resistant MRSA (n = 10), vancomycin-resistant Enterococcus (n = 37), high-level gentamicin-resistant Enterococcus (n = 15), linezolid-resistant Enterococcus (n = 5), and daptomycin-nonsusceptible Enterococcus faecalis (n = 6). For the staphylococci, there was 98.9% categorical agreement (CA). There was one very major error (VME) for gentamicin in a Staphylococcus hominis isolate, six VMEs for inducible clindamycin in S. aureus isolates, and two major errors (ME) for daptomycin in an S. aureus and a Staphylococcus epidermidis isolate. For enterococci, there was 97.3% CA. Two VMEs were observed for daptomycin in isolates of E. faecalis and 2 ME, 1 for high-level gentamicin resistance and 1 for nitrofurantoin, in E. faecium isolates. Overall, there was 98.3% CA and 99% essential agreement for the testing of staphylococci and enterococci by the Vitek 2. With the exception of detecting ICR in S. aureus, Vitek 2 performed reliably for antimicrobial susceptibility testing of staphylococci and enterococci.
Chalmers, Gabhan; McLean, John; Hunter, D Bruce; Brash, Marina; Slavic, Durda; Pearl, David L; Boerlin, Patrick
Pododermatitis is a disease of concern for mink breeders in Canada and worldwide, as it causes discomfort and lowers the breeding rates on farms affected by the disease. Unfortunately, the etiology and pathogenesis of pododermatitis are still unknown. In this study, we compared Staphylococcus spp. and Streptococcus canis isolates from healthy mink with isolates from animals with pododermatitis on 2 farms in Ontario. Almost all hemolytic Staphylococcus spp. isolated were shown to be Staphylococcus delphini Group A by 16S ribosomal ribonucleic acid (rRNA) sequence analysis and polymerase chain reaction (PCR). Pulsed-field gel electrophoresis (PFGE) did not reveal any S. delphini or S. canis clonal lineages specifically associated with pododermatitis, which suggests that these bacteria do not act as primary pathogens, but does not dismiss their potential roles as opportunistic pathogens. While S. delphini and S. canis were the most prevalent bacterial pathogens in mink pododermatitis, they were also present in samples from healthy mink. Arcanobacterium phocae is occasionally isolated from pododermatitis cases, but is difficult to recover with conventional culture methods due to its slow growth. A quantitative real-time PCR was developed for the detection of A. phocae and was tested on 138 samples of footpad tissues from 14 farms. The bacterium was detected only in pododermatitis-endemic farms in Canada and was at higher concentrations in tissues from infected footpads than in healthy tissues. This finding suggests that A. phocae is involved in the pathogenesis of pododermatitis.
Couto, Isabel; Sanches, Ilda Santos; Sá-Leão, Raquel; de Lencastre, Hermínia
We previously characterized over 100 Staphylococcus sciuri isolates, mainly of animal origin, and found that they all carried a genetic element (S. sciuri mecA) closely related to the mecA gene of methicillin-resistant Staphylococcus aureus (MRSA) strains. We also found a few isolates that carried a second copy of the gene, identical to MRSA mecA. In this work, we analyzed a collection of 28 S. sciuri strains isolated from both healthy and hospitalized individuals. This was a relatively heterogeneous group, as inferred from the different sources, places, and dates of isolation and as confirmed by pulsed-field gel electrophoresis analysis. All strains carried the S. sciuri mecA copy, sustaining our previous proposal that this element belongs to the genetic background of S. sciuri. Moreover, 46% of the strains also carried the MRSA mecA copy. Only these strains showed significant levels of resistance to beta-lactams. Strikingly, the majority of the strains carrying the additional MRSA mecA copy were obtained from healthy individuals in an antibiotic-free environment. Most of the 28 strains were resistant to penicillin, intermediately resistant to clindamycin, and susceptible to tetracycline, erythromycin, and gentamicin. Resistance to these last three antibiotics was found in some strains only. The findings reported in this work confirmed the role of S. sciuri in the evolution of the mechanism of resistance to methicillin in staphylococci and suggested that this species (like the pathogenic staphylococci) may accumulate resistance markers for several classes of antibiotics. PMID:10699009
Boretti, Vanessa Stolf; Corrêa, Renata Nunes; dos Santos, Silvana Soléo Ferreira; Leão, Mariella Vieira Pereira; Silva, Célia Regina Gonçalves e
Objective: To evaluate the presence of microorganisms of the genus Staphylococcus and Streptococcus on toys in the playroom of a teaching hospital, as well to as analyze the antimicrobial resistance from isolated strains. Methods: Samples were collected from 60 toys, using wet swabs, soon after being used by the children. The samples were inoculated in enriched and selective agar for isolation and later identification of the microorganisms. Antibiogram testing was performed by agar diffusion technique. Results: The genus Staphylococcus was present in 87.0% (52/60) of the toys. Seventy-three strains were isolated, with 29.0% (21/73) coagulase-positive and 71.0% (52/73) coagulasenegative. Among the coagulase-negative strains, 90.4% were resistant to penicillin, 65.4% to oxacillin, 28.8% to clarithromycin, 61.5% to clindamycin, and none to vancomycin. Among the coagulase-positive strains, 76.2% were resistant to penicillin, 23.8% to oxacillin, 23.8% to clarithromycin, 47.6% to clindamycin, and none to vancomycin. The genus Streptococcus was not detected in any of the evaluated toys. Conclusions: Toys can be contaminated with potentially pathogenic bacteria with antimicrobial resistance, representing a possible source of nosocomial infection for patients who are already debilitated. PMID:25479842
Marín, M E; de la Rosa, M C; Cornejo, I
The ability of 135 Staphylococcus strains isolated from Spanish dry-cured hams to produce enterotoxins in culture was investigated by the reversed passive latex agglutination method. A high percentage of enterotoxigenic Staphylococcus aureus strains (85.9%) was recorded, and 54.3% of these produced enterotoxin A. One of the two Staphylococcus epidermidis strains produced enterotoxin C. The reversed passive latex agglutination method yielded satisfactory results. PMID:1575480
Haste, Nina M; Thienphrapa, Wdee; Tran, Dan N; Loesgen, Sandra; Sun, Peng; Nam, Sang-Jip; Jensen, Paul R; Fenical, William; Sakoulas, George; Nizet, Victor; Hensler, Mary E
The rapid rise in antimicrobial resistance in bacteria has generated an increased demand for the development of novel therapies to treat contemporary infections, especially those caused by methicillin-resistant Staphylococcus aureus (MRSA). However, antimicrobial development has been largely abandoned by the pharmaceutical industry. We recently isolated the previously described thiopeptide antibiotic nosiheptide from a marine actinomycete strain and evaluated its activity against contemporary clinically relevant bacterial pathogens. Nosiheptide exhibited extremely potent activity against all contemporary MRSA strains tested including multiple drug-resistant clinical isolates, with MIC values 0.25 mg l(-1). Nosiheptide was also highly active against Enterococcus spp. and the contemporary hypervirulent BI/NAP1/027 strain of Clostridium difficile but was inactive against most Gram-negative strains tested. Time-kill analysis revealed nosiheptide to be rapidly bactericidal against MRSA in a concentration- and time-dependent manner, with a nearly 2-log kill noted at 6 h at 10 × MIC. Furthermore, nosiheptide was found to be non-cytotoxic against mammalian cells at >100 × MIC, and its anti-MRSA activity was not inhibited by 20% human serum. Notably, nosiheptide exhibited a significantly prolonged post-antibiotic effect against both healthcare- and community-associated MRSA compared with vancomycin. Nosiheptide also demonstrated in vivo activity in a murine model of MRSA infection, and therefore represents a promising antibiotic for the treatment of serious infections caused by contemporary strains of MRSA.
Roveta, S; Marchese, A; Schito, G C
The aim of this study was to assess whether the novel lipopeptide daptomycin might be capable of disrupting or inhibiting the synthesis of biofilms produced by staphylococci. Fourteen recently isolated slime-producing methicillin-susceptible (MET-S) and methicillin-resistant (MET-R) strains (three MET-S Staphylococcus aureus, three MET-R S. aureus, three MET-S Staphylococcus epidermidis, three MET-R S. epidermidis and two vancomycin-intermediate S. aureus (VISA)) were tested. Slime formation on polystyrene plates was quantified spectrophotometrically. Daptomycin (2-64 mg/L) inhibited slime synthesis by > or =80% in MET-S strains, by 60-80% in MET-R S. aureus and by 70-95% in MET-R S. epidermidis. At 64 mg/L, biofilm synthesis decreased by 80% in the VISA isolates. Daptomycin also disrupted pre-formed biofilm: >50% breakdown of initial biofilm (5h) was observed in all strains. Disruption of mature biofilms (48 h), in terms of percentage, was more variable depending on the strain, ranging from ca. 20% in a MET-R S. epidermidis strain to almost 70% in two MET-S strains (one S. aureus and one S. epidermidis). Daptomycin at concentrations achievable during therapy promoted a statistically significant inhibition of slime synthesis (preventing biofilm building) and induced slime disruption (disaggregating its structure) both in initial and mature biofilms on a plastic support in all staphylococcal strains studied.
Mendes, Rodrigo E; Sader, Helio S; Jones, Ronald N
The activity of telavancin was evaluated against Staphylococcus spp. collected from European hospitals as part of an international surveillance study (2007-2008). A total of 7534 staphylococcal clinical isolates [5726 Staphylococcus aureus and 1808 coagulase-negative staphylococci (CoNS)] were included. Isolates were tested for susceptibility according to reference methods and minimum inhibitory concentration (MIC) values were interpreted based on Clinical and Laboratory Standards Institute (CLSI) 2010 and European Committee on Antimicrobial Susceptibility Testing (EUCAST) 2009 criteria. Telavancin breakpoints approved by the US Food and Drug Administration (FDA) were applied. Telavancin activity was evaluated against meticillin-resistant S. aureus (MRSA) displaying several antibiogram resistance patterns, including multidrug-resistant isolates. Telavancin was active against S. aureus [MIC(50/90) values (MICs for 50% and 90% of the isolates, respectively)=0.12/0.25mg/L; 100.0% susceptible] and CoNS (MIC(50/90)=0.12/0.25mg/L), inhibiting all isolates at < or =0.5mg/L. Similar results were observed when S. aureus were stratified by year or country of origin (MIC(50/90)=0.12/0.25mg/L). When MRSA isolates were clustered according to 48 different resistance patterns, telavancin showed consistent MIC(90) values (0.25mg/L) regardless of multidrug resistance. Amongst CoNS, telavancin was slightly more active against Staphylococcus capitis, Staphylococcus epidermidis, Staphylococcus hominis, Staphylococcus lugdunensis and Staphylococcus xylosus (MIC(50)=0.12 mg/L) compared with Staphylococcus haemolyticus, Staphylococcus saprophyticus and Staphylococcus warneri (MIC(50)=0.25mg/L). Overall, telavancin exhibited MIC(90) results two- to eight-fold lower than comparators (daptomycin, quinupristin/dalfopristin, vancomycin and linezolid). Based upon MIC(90) values, telavancin demonstrated potent in vitro activity against a contemporary (2007-2008) collection of Staphylococcus spp
Background Infections by Staphylococcus spp. are often associated with wounds, especially in hospitalized patients. Wounds may be the source of bacteria causing cross-contamination, and are a risk factor for methicillin-resistant Staphylococcus aureus (MRSA) infection. The aim of this study was to investigate the prevalence of wound colonization by Staphylococcus spp., especially S. aureus and MRSA, in hospitalized patients, and to identify the factors associated with such colonization. Methods This cross-sectional study enrolled patients with wounds who were hospitalized in a remote and underdeveloped inland region of northeastern Brazil with extreme poverty. Samples were collected using sterile swabs with 0.85% saline solution, and coagulase-negative Staphylococcus spp., S. aureus, and MRSA were identified using standard laboratory procedures. Data regarding the sociodemographic characteristics, antibiotic use, and comorbidities of the patients were collected using the medical records and a questionnaire. Results A total of 125 wounds were analyzed. The patients had a mean age of 63.88 years and a mean 3.84 years of school education. Eighty-one wounds (64.80%) were colonized by Staphylococcus spp. Twenty-five wounds (20%) were colonized by S. aureus, 32% of which were colonized by MRSA. Wound colonization by Staphylococcus spp. was associated with pneumonia or other respiratory disease (p = 0.03). Wound colonization by S. aureus was associated with nasal colonization by S. aureus (p < 0.001), fewer days of prior antibiotic use (p = 0.04), admission to a medical ward (p = 0.02), and age >65 years (p = 0.05). Among patients with wound colonization by MRSA, 37.50% had a history of prior antibiotic use, 75% had two or more comorbidities, 25% had cancer or diabetes, 50% had cardiovascular disease, and 50% died. Conclusions Wounds can be the source of Staphylococcus spp. infection, and high proportions of wounds are colonized by S. aureus and MRSA. Nasal
Jones, Paul V.; Huey, Shannon; Davis, Paige; McLemore, Ryan; McLaren, Alex
Electrophoretic and dielectrophoretic approaches to separations can provide unique capabilities. In the past, capillary and microchip-based approaches to electrophoresis have demonstrated extremely high-resolution separations. More recently, dielectrophoretic systems have shown excellent results for the separation of bioparticles. Here we demonstrate resolution of a difficult pair of targets: gentamicin resistant and susceptible strains of Staphylococcus epidermidis. This separation has significant potential implications for healthcare. This establishes a foundation for biophysical separations as a direct diagnostic tool, potentially improving nearly every figure of merit for diagnostics and antibiotic stewardship. The separations are performed on a modified gradient insulator-based dielectrophoresis (g-iDEP) system and demonstrate that the presence of antibiotic resistance enzymes (or secondary effects) produces a sufficient degree of electrophysical difference to allow separation. The differentiating factor is the ratio of electrophoretic to dielectrophoretic mobilities. This factor is 4.6 ± 0.6 × 109 V m–2 for the resistant strain, versus 9.2 ± 0.4 × 109 V m–2 for the susceptible strain. Using g-iDEP separation, this difference produces clear and easily discerned differentiation of the two strains. PMID:26086047
Issa-Zacharia, Abdulsudi; Kamitani, Yoshinori; Tiisekwa, Adili; Morita, Kazuo; Iwasaki, Koichi
In the current study, the effectiveness of slightly acidic electrolyzed water (SAEW) on an in vitro inactivation of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Salmonella spp. was evaluated and compared with other sanitizers. SAEW (pH 5.6, 23mg/l available chlorine concentration; ACC; and 940mV oxidation reduction potential; ORP) was generated by electrolysis of dilute solution of HCl (2%) in a chamber of a non-membrane electrolytic cell. One milliliter of bacteria suspension (ca. 10-11 log(10)CFU/ml) was mixed with 9ml of SAEW, strong acidic electrolyzed water (StAEW; ca. 50mg/l ACC), sodium hypochlorite solution (NaOCl; ca.120mg/l ACC) and distilled water (DW) as control and treated for 60s. SAEW effectively reduced the population of E. coli, S. aureus and Salmonella spp. by 5.1, 4.8, and 5.2 log(10)CFU/ml. Although, ACC of SAEW was more than 5 times lower than that of NaOCl solution, they showed no significant bactericidal difference (p>0.05). However, the bactericidal effect of StAEW was significantly higher (p<0.05) than SAEW and NaOCl solution in all cases. When tested with each individual test solution, E. coli, S. aureus and Salmonella spp. reductions were not significantly different (p>0.05). These findings indicate that SAEW with low available chlorine concentration can equally inactivate E. coli, S. aureus and Salmonella spp. as NaOCl solution and therefore SAEW shows a high potential of application in agriculture and food industry as an environmentally friendly disinfection agent.
Campos-Peña, E; Martín-Nuñez, E; Pulido-Reyes, G; Martín-Padrón, J; Caro-Carrillo, E; Donate-Correa, J; Lorenzo-Castrillejo, I; Alcoba-Flórez, J; Machín, F; Méndez-Alvarez, S
We describe a new, efficient, sensitive, and fast single-tube multiple-PCR protocol for the identification of the most clinically significant Staphylococcus spp. and the simultaneous detection of the methicillin and mupirocin resistance loci. The protocol identifies at the species level isolates belonging to S. aureus, S. epidermidis, S. haemolyticus, S. hominis, S. lugdunensis, and S. saprophyticus.
Chajęcka-Wierzchowska, Wioleta; Zadernowska, Anna; Nalepa, Beata; Sierpińska, Magda; Laniewska-Trokenheim, Lucja
Ready-to-eat (RTE) food, which does not need thermal processing before consumption, could be a vehicle for the spread of antibiotic-resistant microorganisms. As part of general microbiological safety checks, staphylococci are routinely enumerated in these kinds of foods. However, the presence of antibiotic-resistant staphylococci in RTE food is not routinely investigated, and data are only available from a small number of studies. The present study evaluated the pheno- and genotypical antimicrobial resistance profile of Staphylococcus spp. isolated from 858 RTE foods (cheeses, cured meats, sausages, smoked fishes, salads). Of 113 strains isolated, S. aureus was the most prevalent species, followed by S. xylosus, S. saprophyticus, and S. epidermidis. More than half (54.9%) of the isolates were resistant to at least one class of tested antibiotic; of these, 35.4% of the strains were classified as multidrug resistant. Most of the isolates were resistant to cefoxitin (49.6%), followed by clindamycin (39.3%), tigecycline (27.4%), quinupristin-dalfopristin (22.2%), rifampin (20.5%), tetracycline (17.9%), and erythromycin (8.5%). All methicillin-resistant staphylococci harbored the mecA gene. Among the isolates resistant to at least one antibiotic, 38 harbored tetracycline resistance determinant tet (M), 24 harbored tet (L), and 9 harbored tet (K). Of the isolates positive for tet (M) genes, 34.2% were positive for the Tn916-Tn1545-like integrase family gene. Our results indicated that retail RTE food could be considered an important route for the transmission of antibiotic-resistant bacteria harboring multiple antibiotic resistance genes.
Gasc, Cyrielle; Richard, Jean-Yves
Staphylococcus aureus strain HUK16 has been isolated from hexachlorocyclohexane (HCH)-long-term contaminated soil. The genome of strain HUK16 was sequenced to understand the genetic basis of its adaptation to HCH and to find the potential metabolic pathways allowing it to degrade the pesticide. Here, we report the annotated draft genome sequence (~2.7 Mbp) of this strain. PMID:27081139
Gouriet, Frédérique; Gimenez, Grégory; Robert, Catherine; Raoult, Didier
We applied real-time genome sequencing to a Staphylococcus epidermidis strain that caused native-aortic-valve endocarditis in a 26-year-old patient. The 2.5-Mb genome from strain CSUR P278 exhibited a unique sequence type among S. epidermidis strains and contained 32 genes previously considered virulence genes in this species. PMID:23363834
Łysakowska, Monika E; Ciebiada-Adamiec, Anna; Klimek, Leszek; Sienkiewicz, Monika
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.
Carroll, Ronan K; Burda, Whittney N; Roberts, Jill C; Peak, Kealy K; Cannons, Andrew C; Shaw, Lindsey N
We present the draft genome sequence of methicillin-resistant Staphylococcus aureus strain CBD-635, from the USA100 lineage. This is a sepsis isolate obtained from Tampa General Hospital. This strain is spa type t003 and multilocus sequence typing (MLST) type ST5, and it has been used by our group in the study of novel antimicrobial chemotherapeutics.
Pin, C; Marín, M L; Selgas, D; García, M L; Tormo, J; Casas, C
Production of several extracellular virulence factors (lipase, protease and haemolysin) was compared in 15 Aeromonas spp. isolated from faeces of patients with Aeromonas-associated gastroenteritis and 81 strains isolated from food. Strains from food did not show differences in production of these factors when compared with strains isolated from faeces. However, if strains were considered in relation to autoagglutination (AA) character, the AA+ differed from AA- strains in lipase and protease production. Supernatant fluids of AA+ food and human strains showed 2.5-fold more protease production than that observed in AA- strains. These two characteristics of certain Aeromonas strains could be related with the more virulent capacity.
Robert, Catherine; Gimenez, Grégory; Raoult, Didier
A draft genome sequence of Staphylococcus massiliensis, Gram-positive cocci isolated from a human brain abscess sample, is described here. One clustered regularly interspaced short palindromic repeat, three transposases, six putative transposases, and one potential provirus were characterized. PMID:23209235
The striking ecological, metabolic, and biochemical diversity of Pseudomonas has intrigued microbiologists for many decades. To explore the genomic diversity of biocontrol strains of Pseudomonas spp., we derived high quality draft sequences of seven strains known to suppress plant disease. The str...
Genome sequencing, data mining and mass spectrometry were used to identify secondary metabolites produced by several Bacillus spp. biocontrol strains. These biocontrol strains have shown promise in managing Fusarium head blight in wheat. Draft genomes were produced and screened in silico using genom...
Oliveira, Ana Maria; Padovani, Carlos Roberto; Miya, Norma Teruko Nagô; Sant'ana, Anderson S; Pereira, José Luiz
In this study, the enterotoxigenic potential of Staphylococcus strains (n = 574) isolated from raw milk samples (n = 140) was determined for their capacity to produce staphylococcal enterotoxins. In addition, the relationship between the presence of enterotoxins, coagulase, and thermonuclease (Tnase) was assessed. The results showed that 19% of Staphylococcus was enterotoxigenic, being able to produce at least one of the staphylococcal enterotoxins (A, B, C, and D). Most of the strains were able to produce enterotoxin D (68.8%), whereas 12.8% of the Staphylococcus strains were able to produce staphylococcal enterotoxin A. Besides, the production of more than one type of enterotoxins by the same strain was observed. Tnase was considered the best marker for enterotoxigenic potential of isolates, although some of them were negative for coagulase and Tnase but positive for enterotoxin production. Therefore, either the use of Tnase to assess Staphylococcus enterotoxigenic potential or the use of simple and easy screening tests for enterotoxin production should receive more attention when evaluating the pathogenic potential of foodborne Staphylococcus strains. Due to the association of both coagulase positive Staphylococcus and coagulase negative Staphylococcus with foodborne disease outbreaks, regulators and industries should pay more attention to enterotoxigenic Staphylococcus rather than focusing only on S. aureus or coagulase positive Staphylococcus. Finally, data found here suggest a high risk of staphylococcal intoxication with the consumption of raw milk or dairy products made from raw milk.
Kornienko, M A; Kopyltsov, V N; Shevlyagina, N V; Didenko, L V; Lyubasovskaya, L A; Priputnevich, T V; Ilina, E N
The urgency of the staphylococcus research is due to its ability to cause severe infections: softtissue infections, endocarditis, sepsis, toxic shock syndrome, and food poisoning. Coagulase-positive Staphylococcus aureus is the main infection agent of intrahospital infections. This agent has many factors of pathogenicity, which are well known. Among the coagulase-negative staphylococcus (CNS) strains, S. haemolyticus and S. epidermidis are clinically important, because they cause infections in patients with weak immune system. The mechanisms of the CNS pathogenicity are insufficiently understood. The goal of this work was to evaluate the potential pathogenicity of clinical strains of CNS from their capacity to create biofilms and the character of their interaction with human body cells by the example of the HT-29 cell culture. The research was carried out in laboratory strain S. aureus ATCC 29213 and clinical strains S. haemolyticus SH39, S. epidermidis SE36-1 isolated from the neonatal autopsy materials. The visual tests of biofilm formation by each strain and testing of the impact of the strains on the cell culture HT-29 was carried out in this work. The two species of CNS form biofilms at a higher rate than S. aureus. Upon incubation for 2 h of HT-29 cells with staphylococcus strains tested in this work, adhesion of bacteria on cell surface was observed. The adhesion was most pronounced in case of S. aureus ATCC 29213 and S. haemolyticus SH39. Upon 3 h of incubation with S. aureus ATCC 29213 and S. haemolyticus SH39, destruction of cell HT-29 monolayer was observed. The incubation for 24 h with the 3 strains tested in this work caused complete destruction of cell HT-29 monolayer. The maximal toxic effect on HT-29 cells was inherent in the strain S. haemolyticus SH39. The aggregate of the results obtained in this work indicates the presence of the pathogenicity factors in the strains S. haemolyticus SH39, which require additional research.
Nakipoglu, Yasar; Derbentli, Sengul; Cagatay, Atahan A; Katranci, Handan
Background The hetero-glycopeptide intermediate staphylococci is considered to be the precursor of glycopeptide intermediate staphylococci especially vancomycin intermediate Staphylococcus aureus (VISA). For this purpose, we aimed to investigate the heterogeneous resistance to glycopeptide and their frequencies in 135 Staphylococcus strains. Methods Heterogeneous resistance of Staphylococcus strains was detected by inoculating the strains onto Brain Heart Infusion agar supplemented with 4 mg/L of vancomycin (BHA-V4). Agar dilution method was used for determining MICs of glycopeptides and population analysis profile was performed for detecting frequency of heterogeneous resistance for the parents of selected strains on BHA-4. Results Eight (6%) out of 135 Staphylococcus strains were exhibited heterogeneous resistance to at least one glycopeptide. One (1.2%) out of 81 S. aureus was found intermediate resistance to teicoplanin (MIC 16 mg/L). Other seven strains were Staphylococcus haemolyticus (13%) out of 54 coagulase negative staphylococci (CoNS). Six of the seven strains were detected heterogeneously reducing susceptibility to vancomycin (MICs ranged between 5–8 mg/L) and teicoplanin (MICs ranged between 32–64 mg/L), and one S. haemolyticus was found heterogeneous resistance to teicoplanin (MIC 32 mg/L). Frequencies of heterogeneous resistance were measured being one in 106 – 107 cfu/ml. MICs of vancomycin and teicoplanin for hetero-staphylococci were determined as 2–6 folds and 3–16 folds higher than their parents, respectively. These strains were isolated from six patients (7%) and two (4%) of health care wokers hands. Hetero-VISA strain was not detected. Conclusion Heterogeneous resistance to glycopeptide in CoNS strains was observed to be significantly more emergent than those of S. aureus strains (vancomycin P 0.001, teicoplanin, P 0.007). The increase MICs of glycopeptide resistance for subpopulations of staphylococci comparing with their parents
Melconian, A. K.; Brun, Y.; Fleurette, J.
The production of enterotoxins A, B, C and F by strains of Staphylococcus aureus isolated from various clinical sources and from isolates implicated in food poisoning was investigated. One hundred and ninety one of the 374 clinical strains (51.1%) were found to be enterotoxigenic; of these, 81 (27.7%) strains produced enterotoxin A, 57 (15.3%) strains produced enterotoxin B, 23 (6.2%) strains produced enterotoxin C, and 64 (17.1%) strains produced enterotoxin F. These enterotoxigenic strains were most frequently lysed by phages of group III (21.5%) or were not typable (22%). Eighteen of the 29 strains implicated in food poisoning were enterotoxigenic. The correlation of antigens and bacteriophage patterns with enterotoxigenicity was determined: enterotoxin A being related to a4 antigen, enterotoxin B to phages of 94/96 complex with c1, o antigens, and enterotoxin F to phages of group I with 2632, k1k2, m antigens. PMID:6227656
Santos, Olinda Cabral Silva; Duarte, Andreza Freitas Souza; Albano, Rodolpho Mattos
Here, we present the 2,658,363-bp draft genome sequence of the aureocin A53–producing strain Staphylococcus aureus A53. This genome information may contribute to the optimal and rational exploitation of aureocin A53 as an antimicrobial agent and to its production in large scale. PMID:27563042
Kant, Ravi; Taponen, Suvi; Koort, Joanna; Paulin, Lars; Åvall-Jääskeläinen, Silja; Palva, Airi
Staphylococcus aureus is a major causative agent of mastitis in dairy cows. The pathogenicity of S. aureus may vary; it is able to cause severe clinical mastitis, but most often it is associated with chronic subclinical mastitis. Here, we present the genome assemblies of four S. aureus strains from bovine mastitis.
Lassen, Simon B.; Lomholt, Hans B.
ABSTRACT Staphylococcus epidermidis is a Gram-positive bacterium that is prevalent on human skin. The species is associated with skin health, as well as with opportunistic infections. Here, we report the complete genome sequence of S. epidermidis 14.1.R1, isolated from human skin. In bacterial interference assays, the strain showed exceptional antimicrobial activity. PMID:28280007
Sharma, Paresh; Reddy, D. Peddi; Kumar, P. Anand; Gadicherla, Ramya; George, Neena
We report here the draft genome of Staphylococcus aureus causing clinical mastitis in a cow from India. It is a major causative agent of mastitis and, further, livestock-associated strains are emerging as a potential threat to public health, thereby warranting studies to understand the genome of this deadly pathogen. PMID:26294628
Albert, Ervin; Nagy, Tibor; Olasz, Ferenc; Barta, Endre; Kiss, János; Dán, Ádám; Bányai, Krisztián; Hermans, Katleen; Biksi, Imre
We report the draft genome sequence of Staphylococcus aureus Sp17, a typical highly virulent (HV) rabbit strain. As current medicine apparently fails to effectively reduce disease and economical losses caused by this organism, it is essential to gain better insight on its genomic arrangement. PMID:26159520
Silva, Danielle Mendes; da Silva, Mônica Pacheco; Vidigal, Pedro M Pereira; Barcelos, Rafael Mazioli; Klein, Raphael Contelli; Aguilar, Ananda Pereira; Fabres-Klein, Mary Hellen; Oliveira, Guilherme; Ribon, Andréa Oliveira Barros
Here, we present the draft genome sequences of four Staphylococcus aureus strains isolated from mastitic milk collected from animals with subclinical manifestations. Three of them were typed as sequence type 126 (ST126), a genotype with no genome sequence available. ST126 is found in several herds of southern Brazil and is described as a bovine pathogen strongly associated with milk around the world.
Sommers, Christopher; Gunther, Nereus W; Sheen, Shiowshuh
Raw poultry are sometimes contaminated with foodborne pathogens, which can lead to illness in humans. In recent years research has focused on a variety of light technologies to decontaminate food and food contact surfaces during meat and poultry processing. In this study we evaluated the ability of 405-nm light generated from an LED array to inactivate multi-isolate cocktails of either Salmonella spp., pathogenic Escherichia coli, Staphylococcus spp., or Listeria monocytogenes suspended in chicken purge or skin. When exposed to 180 J/cm(2) 405-nm light at two separate light intensities (300 mW/cm(2)/s or 150 mW/cm(2)/s) the maximum pathogen reduction on chicken skin was ca. 0.4 log. When the pathogens were suspended in chicken purge the maximum log reductions ranged from 0.23 to 0.68 log (180 J/cm(2); 150 mW/cm(2)/s) versus 0.69 to 1.01 log (180 J/cm(2); 300 mW/cm(2)/s). Log reductions of each pathogen, when they were subjected to heat shock prior to 405-nm light treatment, were reduced, indicating that thermal effects accounted for much of the bacterial inactivation.
Rossi, Ciro C; Ferreira, Natália C; Coelho, Marcus L V; Schuenck, Ricardo P; Bastos, Maria do Carmo de F; Giambiagi-deMarval, Marcia
Coagulase-negative staphylococci are thought to act as reservoirs of antibiotic resistance genes that can be transferred to Staphylococcus aureus, thus hindering the combat of this bacterium. In this work, we analyzed the presence of plasmids conferring resistance to the antibiotic mupirocin-widely used to treat and prevent S. aureus infections in hospital environments-in nosocomial S. haemolyticus strains. About 12% of the 75 strains tested were resistant to mupirocin, and this phenotype was correlated with the presence of plasmids. These plasmids were shown to be diverse, being either conjugative or mobilizable, and capable of transferring mupirocin resistance to S. aureus Our findings reinforce that S. haemolyticus, historically and mistakenly considered as a less important pathogen, is a reservoir of resistance genes which can be transferred to other bacteria, such as S. aureus, emphasizing the necessity of more effective strategies to detect and combat this emergent opportunistic pathogen.
Zajmi, Asdren; Mohd Hashim, Najihah; Noordin, Mohamed Ibrahim; Khalifa, Shaden A M; Ramli, Faiqah; Mohd Ali, Hapipah; El-Seedi, Hesham R
Staphylococci are facultative anaerobes, perfectly spherical un-encapsulated cocci, with a diameter not exceeding 1 micrometer in diameter. Staphylococcus aureus are generally harmless and remain confined to the skin unless they burrow deep into the body, causing life-threatening infections in bones, joints, bloodstream, heart valves and lungs. Among the 20 medically important staphylococci species, Staphylococcus aureus is one of the emerging human pathogens. Streptomycin had its highest potency against Staphylococcus infections despite the likelihood of getting a resistant type of staphylococcus strains. Methicillin-resistant S. aureus (MRSA) is the persister type of Staphylococcus aureus and was evolved after decades of antibiotic misuse. Inadequate penetration of the antibiotic is one of the principal factors related to success/failure of the therapy. The active drug needs to reach the bacteria at concentrations necessary to kill or suppress the pathogen's growth. In turn the effectiveness of the treatment relied on the physical properties of Staphylococcus aureus. Thus understanding the cell integrity, shape and roughness is crucial to the overall influence of the therapeutic agent on S. aureus of different origins. Hence our experiments were designed to clarify ultrastructural changes of S. aureus treated with streptomycin (synthetic compound) in comparison to artonin E (natural compound). In addition to the standard in vitro microbial techniques, we used transmission electron microscopy to study the disrupted cell architecture under antibacterial regimen and we correlate this with scanning electron microscopy (SEM) to compare results of both techniques.
Background Extracellular bacterial lipases received much attention for their substrate specificity and their ability to function under extreme environments (pH, temperature...). Many staphylococci produced lipases which were released into the culture medium. Reports of extracellular thermostable lipases from Staphylococcus sp. and active in alkaline conditions are not previously described. Results This study focused on novel strategies to increase extracellular lipolytic enzyme production by a novel Staphylococcus sp. strain ESW. The microorganism needed neutral or alkaline pH values between 7.0 and 12.0 for growth. For pH values outside this range, cell growth seemed to be significantly inhibited. Staphylococcus sp. culture was able to grow within a wide temperature range (from 30 to 55°C). The presence of oils in the culture medium leaded to improvements in cells growth and lipolytic enzyme activity. On the other hand, although chemical surfactants leaded to an almost complete inhibition of growth and lipolytic enzyme production, their addition along the culture could affect the location of the enzyme. In addition, our results showed that this novel Staphylococcus sp. strain produced biosurfactants simultaneously with lipolytic activity, when soapstock (The main co-product of the vegetable oil refining industry), was used as the sole carbon source. Conclusion A simultaneous biosurfactant and extracellular lipolytic enzymes produced bacterial strain with potential application in soap stock treatment PMID:22078466
Miklasińska, Maria; Kępa, Małgorzata; Wojtyczka, Robert D; Idzik, Danuta; Dziedzic, Arkadiusz; Wąsik, Tomasz J
Synergistic effects between commonly used antibiotics and natural substances may be an alternative to conventional antibacterial therapies. The objective of the presented study was to assess the in vitro antibacterial activity of catechin hydrate (CH) and evaluate the interactions of CH with selected antibiotics using Staphylococcus aureus clinical and reference strains. CH displayed diverse activity towards examined S. aureus strains, with minimal inhibitory concentrations (MICs) ranging from 256 to 2048 µg/mL. The interaction between CH and antibiotics was assessed by an E-test. The most significant synergistic effects were noticed for CH in combination with clindamycin and erythromycin. For cefoxitin and vancomycin a decrease of MIC values in the presence of CH was also observed, but it did not reach statistical significance. The obtained results demonstrate that CH shows antimicrobial activity against Staphylococcus aureus clinical strains. What is more, we proved a synergistic effect of CH with erythromycin and clindamycin.
Vogel, L; Nathan, C; Sweeney, H M; Kabins, S A; Cohen, S
An apparently homogeneous strain of Staphylococcus aureus resistant to gentamicin (Gmr), kanamycin, tobramycin, and sisomicin, but susceptible to amikacin and netilmicin, caused multiple infections in neonatal infants in a special care nursery. Nasal cultures revealed a high rate of carriage of the Gmr staphylococcus in infants without clinical infection. Segregating patients according to a modified cohort system and use of careful aseptic techniques led to apparent elimination of the Gmr strain. The resistance to aminoglycosides in this strain was mediated by an aminoglycoside 6'-N-acetyltransferase and a gentamicin phosphotransferase. Genetic determinants for these enzymes were borne on a circular covalently closed plasmid of approximately 11 megadaltons. These resistance determinants closely resemble those found in isolates of S. aureus that have caused nosocomial infections in patients in Europe. PMID:263886
Sousa, Margarida; Silva, Nuno; Igrejas, Gilberto; Silva, Filipe; Sargo, Roberto; Alegria, Nuno; Benito, Daniel; Gómez, Paula; Lozano, Carmen; Gómez-Sanz, Elena; Torres, Carmen; Caniça, Manuela; Poeta, Patrícia
Antibiotic resistance among wild animals represent an emerging public health concern. The objective of this study was to analyze the staphylococcal nasal microbiota in birds of prey and their content in antimicrobial resistance determinants. Nasal samples from 16 birds of prey were collected, swabs were dipped and incubated into BHI broth [6.5% NaCl] and later seeded on manitol salt agar and oxacillin-resistance screening agar base media. Staphylococcal colonies were isolated from both media and were identified by biochemical and molecular methods. Susceptibility testing to 18 antimicrobial agents was performed by disk-diffusion method. Six of the 16 tested animals carried staphylococci (37.5%) and 7 isolates of the following species were recovered: Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Staphylococcus sciuri rodentium, Staphylococcus cohnii urealitycum, and Staphylococcus gallinarum. The S. aureus isolate was penicillin-resistant (with blaZ gene) but methicillin-susceptible and was ascribed to spa-type t012, sequence-type ST30 and agr-type III. The S. epidermidis isolate carried blaZ, mecA, mrs(A/B), mphC, tet(K), drfA, and fusC genes, ica operon, and was typed as ST35. The genes ant6'-Ia, tet(K), tet(L), dfrG, cat221, cat194, and cat223 were detected in S. saprophyticus or S. gallinarum isolates. Birds of prey seem to be a natural reservoir of S. aureus and coagulase-negative staphylococci resistant to multiple antibiotics. Due to the convergence between habitats, the contact between wildlife, other animals and humans is now more common and this involves an increased possibility of interchange of these microorganisms in the different ecosystems.
Daum, Luke T; Bumah, Violet V; Masson-Meyers, Daniela S; Khubbar, Manjeet; Rodriguez, John D; Fischer, Gerald W; Enwemeka, Chukuka S; Gradus, Steve; Bhattacharyya, Sanjib
We report here the whole-genome sequence of the USA300 strain of methicillin-resistant Staphylococcus aureus (MRSA), designated ATCC BAA-1680, and commonly referred to as community-associated MRSA (CA-MRSA). This clinical MRSA isolate is commercially available from the American Type Culture Collection (ATCC) and is widely utilized as a control strain for research applications and clinical diagnosis. The isolate was propagated in ATCC medium 18, tryptic soy agar, and has been utilized as a model S. aureus strain in several studies, including MRSA genetic analysis after irradiation with 470-nm blue light.
Pumarola, J; Berástegui, E; Canalda, C; Brau, E
The mean goal of this study is the determination of the conduct of 120 strains of Staphylococcus aureus against seven root canal sealers: Traitement Spad, Endométhasone, N2 Universal, AH26 with silver, Diaket-A, Tubli Seal and Sealapex. The agar diffusion test was employed in the determination of its bacterial growth inhibition. The results obtained have demonstrated values very different between the tested strains. Therefore we recommended to employ strains with reference in the investigation of the bacterial growth inhibition in order to repeat equal experimentation conditions.
Liesse Iyamba, J M; Seil, M; Nagant, C; Dulanto, S; Deplano, A; El Khattabi, C; Takaisi Kikuni, N B; Dehaye, J P
The effect of EGTA on the adhesion and on the formation of a biofilm by two reference and eight clinical strains of Staphylococcus aureus was studied. All the clinical strains were isolated from patients from Kinshasa. Spa typing confirmed that these clinical strains were distinct. The Biofilm Ring Test (BFRT®) showed that EGTA (100 µM-10 mM) inhibited the adhesion of the four clinical methicillin-resistant (MRSA) strains and the crystal violet staining method that it inhibited the formation of a biofilm by all the strains. Divalent cations abolished the effect of EGTA on the formation of a biofilm, specially in the clinical MRSA strains. EGTA had no effect on established biofilms. Only concentrations of EGTA higher than 10 mM were toxic to eukaryotic cells. Our results establish the effectiveness and the safety of lock solutions with EGTA to prevent the formation in vitro of biofilms by S. aureus.
Perin, Luana Martins; Todorov, Svetoslav Dimitrov; Nero, Luís Augusto
Different strains of Lactococcus lactis are capable of producing the bacteriocin nisin. However, genetic transfer mechanisms allow the natural occurrence of genes involved in nisin production in members of other bacterial genera, such as Enterococcus spp. In a previous study, nisA was identified in eight enterococci capable of producing antimicrobial substances. The aim of this study was to verify the presence of genes involved in nisin production in Enterococcus spp. strains, as well as nisin expression. The nisA genes from eight Enterococcus spp. strains were sequenced and the translated amino acid sequences were compared to nisin amino-acid sequences previously described in databases. Although containing nisin structural and maturation related genes, the enterococci strains tested in the present study did not present the immunity related genes (nisFEG and nisI). The translated sequences of nisA showed some point mutations, identical to those presented by Lactococcus strains isolated from goat milk. All enterococci were inhibited by nisin, indicating the absence of immunity and thus that nisin cannot be expressed. This study demonstrated for the first time the natural occurrence of nisin structural genes in Enterococcus strains and highlights the importance of providing evidence of a link between the presence of bacteriocin genes and their expression.
Kerns, Robert J; Rybak, Michael J; Kaatz, Glenn W; Vaka, Flamur; Cha, Raymond; Grucz, Richard G; Diwadkar, Veena U
We previously demonstrated that piperazinyl-linked fluoroquinolone dimers possess potent antibacterial activity against drug-resistant strains of Staphylococcus aureus. In this study, we report the preparation and evaluation of a series of incomplete dimers toward ascertaining structural features of piperazinyl-linked ciprofloxacin dimers that render these agents refractory to fluoroquinolone-resistance mechanisms in Staphylococcus aureus.
Kuusela, P; Hildén, P; Savolainen, K; Vuento, M; Lyytikäinen, O; Vuopio-Varkila, J
Seventy-nine methicillin-resistant Staphylococcus aureus (MRSA) strains, isolated during 1980 to 1990, were classified as MRSA Aggl- (14 strains) and MRSA Aggl+ (65 strains) strains on the basis of test results in slide agglutination assays designed to detect fibrinogen-binding protein (clumping factor) and protein A on the staphylococcal surface. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that lysostaphin digests of MRSA Aggl- strains contained a high-molecular-weight protein which was not detected in digests of MRSA Aggl+ strains. Immunization of rabbits with an MRSA Aggl- strain produced an antiserum which agglutinated all MRSA Aggl- strains and also 64 of 65 MRSA Aggl+ strains. Only 1 of 68 coagulase-negative staphylococci showed agglutination in this assay. The anti-MRSA Aggl- antiserum reacted mainly with a 230-kDa staphylococcal surface protein but also with a 175-kDa protein, probably formed by proteolysis of the former and a few slightly smaller proteins. These could not be immunologically detected in lysostaphin digests of MRSA Aggl+ strains. Purified antibodies reacting with the 230-kDa protein agglutinated all MRSA Aggl- strains, indicating that the protein is located on the surfaces of staphylococci. The results suggest a tentative role for the 230-kDa protein or its fragments as a novel target to develop more efficient rapid identification methods for S. aureus, including MRSA. Images PMID:8126170
Fontana, C; Cellini, L; Dainelli, B
A new biovar of Staphylococcus aureus subsp. aureus was isolated from human clinical specimens and described on the basis of studies of 12 isolates that were compared with 11 standard reference strains. Both DNA hybridization experiments and numerical taxonomy analysis demonstrated that these strains were strictly related to S. aureus subsp. aureus; however, they were significantly different from the latter. The atypical strains belonging to the new biovar can be distinguished from typical S. aureus subsp. aureus strains by their alpha-chymotrypsin, alpha-glucosidase, beta-N-acetylglucosaminidase, lipase (C-14), and leucine arylamidase enzymatic activities and novobiocin resistance. Thus, the combination of alpha-glucosidase and beta-N-acetyl-glucosaminidase is more useful for distinguishing these S. aureus strains from the other, typical ones. PMID:8370737
Stieger, M; Angehrn, P; Wohlgensinger, B; Gmünder, H
The sequence of the gyrase B subunit gene from Staphylococcus aureus strains resistant to the gyrase B subunit inhibitors cyclothialidine, coumermycin, and novobiocin has been determined. The residues altered in the resistant gyrase B subunits map to the ATP-binding region, suggesting that the drugs inhibit ATP binding and hydrolysis. The pattern of cross-resistances indicates that the detailed binding mode of the compounds differs. PMID:8849232
da Silva, Mônica Pacheco; Barcelos, Rafael Mazioli; Klein, Raphael Contelli; Aguilar, Ananda Pereira; Fabres-Klein, Mary Hellen; Oliveira, Guilherme
Here, we present the draft genome sequences of four Staphylococcus aureus strains isolated from mastitic milk collected from animals with subclinical manifestations. Three of them were typed as sequence type 126 (ST126), a genotype with no genome sequence available. ST126 is found in several herds of southern Brazil and is described as a bovine pathogen strongly associated with milk around the world. PMID:26893417
Gilmore, Brendan F.
Here, we report the draft genome sequence of Staphylococcus succinus strain CSM-77. This moderately halophilic bacterium was isolated from the surface of a halite sample obtained from a Triassic salt mine. PMID:27284152
Menasria, Taha; Tine, Samir; Mahcene, Djaouida; Benammar, Leyla; Megri, Rochdi; Boukoucha, Mourad; Debabza, Manel
A study was performed to estimate the prevalence of the external bacterial flora of two domestic cockroaches (Blattella germanica and Blatta orientalis) collected from households in Tebessa (northeast Algeria). Three major bacterial groups were cultured (total aerobic, enterobacteria, and staphylococci) from 14 specimens of cockroaches, and antibiotic susceptibility was tested for both Staphylococcus and Pseudomonas isolates. Culturing showed that the total bacterial load of cockroaches from different households were comparable (P<0.001) and enterobacteria were the predominant colonizers of the insect surface, with a bacterial load of (2.1 × 10⁵ CFU/insect), whereas the staphylococci group was the minority. Twenty-eight bacterial species were isolated, and susceptibility patterns showed that most of the staphylococci isolates were highly susceptible to chloramphenicol, gentamycin, pristinamycin, ofloxacin, clindamycin, and vancomycin; however, Pseudomonas strains exhibited resistance to amoxicillin/clavulanic acid, imipenem, and the second-generation antibiotic cephalosporin cefuroxime.
Cuevas, Oscar; Cercenado, Emilia; Vindel, Ana; Guinea, Jesús; Sánchez-Conde, Matilde; Sánchez-Somolinos, Mar; Bouza, Emilio
Data regarding the evolution of Staphylococcus resistance in a whole country have a definite influence on the design of empirical treatment regimens. Nevertheless, incidence studies over long periods of time are expensive and very difficult to carry out. In order to ascertain the present situation of the antimicrobial resistance of Staphylococcus in Spain and the change of this resistance over time, we performed five point prevalence studies (1986 to 2002) in a large group of Spanish hospitals (from 68 institutions in 1986 to 143 in 2002) collecting all Staphylococcus strains isolated on a single selected day. All microorganisms were identified in the five studies at the same laboratory, and antimicrobial susceptibility testing was performed against 17 antimicrobial agents by the agar dilution method and a microdilution method. During this period, there was an overall increase in resistance to most antimicrobials among Staphylococcus aureus/coagulase-negative staphylococci, mainly to oxacillin (1.5%/32.5% in 1986 versus 31.2%/61.3% in 2002) (P < 0.001), erythromycin (7%/41.1% in 1986 versus 31.7%/63% in 2002) (P < 0.001), gentamicin (5.2%/25.4% in 1986 versus 16.9%/27.8% in 2002) (P < 0.001; P = 0.5), and ciprofloxacin (0.6%/1.1% in 1986 versus 33.9%/44.9% in 2002) (P < 0.001). All of the isolates were uniformly susceptible to glycopeptides, linezolid, and quinupristin/dalfopristin. Resistance of S. aureus to trimethoprim/sulfamethoxazole was very low (from 0.5% to 2.1%) (P = 0.152). Periodic performance of prevalence studies is a useful, inexpensive, and easy tool to know the nationwide situation of a microorganism and its resistance to antimicrobials; it also helps us assess the emergence and spread of antimicrobial resistance. PMID:15504847
Rifai, S; Barbancon, V; Prevost, G; Piemont, Y
Two methods for the detection of exfoliative toxin (ET) from Staphylococcus aureus were compared: (i) a phenotypic assay, electrosyneresis, and (ii) a genotypic assay, staphylococcal DNA hybridization with oligodeoxynucleotide probes. The probes were chosen from the previously determined sequences of serotype A and B of ET, one probe for serotype A and another for serotype B. Strains exhibiting ET production in electrosyneresis always possessed the ET gene(s). Conversely, some strains not exhibiting ET production in electrosyneresis harbored the ET gene(s). The latter strains produced levels of ET. ET-negative phage group 2 strains of S. aureus as well as tested coagulase-negative staphylococci did not possess the ET gene(s). The sensitivity of the DNA hybridization technique was 10(6) bacteria or 100 ng of genomic DNA. Images PMID:2715322
Lyra, Daniele G; Sousa, Francisca G C; Borges, Maria F; Givisiez, Patrícia E N; Queiroga, Rita C R E; Souza, Evandro L; Gebreyes, Wondwossen A; Oliveira, Celso J B
Although Staphylococcus aureus has been implicated as the main Staphylococcus species causing human food poisoning, recent studies have shown that coagulase-negative Staphylococcus could also harbor enterotoxin-encoding genes. Such organisms are often present in goat milk and are the most important mastitis-causing agents. Therefore, this study aimed to investigate the occurrence of enterotoxin-encoding genes among coagulase-positive (CoPS) and coagulase-negative (CoNS) staphylococci isolated from raw goat milk produced in the semi-arid region of Paraiba, the most important region for goat milk production in Brazil. Enterotoxin-encoding genes were screened in 74 staphylococci isolates (30 CoPS and 44 CoNS) by polymerase chain reaction targeting the genes sea, seb, sec, sed, see, seg, seh, and sei. Enterotoxin-encoding genes were found in nine (12.2%) isolates, and four different genes (sea, sec, seg, and sei) were identified amongst the isolates. The most frequent genes were seg and sei, which were often found simultaneously in 44.5% of the isolates. The gene sec was the most frequent among the classical genes, and sea was found only in one isolate. All CoPS isolates (n=7) harboring enterotoxigenic genes were identified as S. aureus. The two coagulase-negative isolates were S. haemolyticus and S. hominis subsp. hominis and they harbored sei and sec genes, respectively. A higher frequency of enterotoxin-encoding genes was observed amongst CoPS (23.3%) than CoNS (4.5%) isolates (p<0.05), reinforcing the importance of S. aureus as a potential foodborne agent. However, the potential risk posed by CoNS in goat milk should not be ignored because it has a higher occurrence in goat milk and enterotoxin-encoding genes were detected in some isolates.
Chrobak, D; Kizerwetter-Świda, M; Rzewuska, M; Moodley, A; Guardabassi, L; Binek, M
The aim of this study was to determine the species distribution among 44 randomly selected clinical isolates (30 mecA-positive and 14 mecA-negative) of animal origin previously identified as Staphylococcus intermedius by phenotypic tests and species-specific PCR amplification of the 16S rRNA gene. For this purpose, we used a multiplex PCR for the detection of the nuc gene and restriction fragment length polymorphism analysis of pta gene amplified by PCR. Both methods allow discrimination of Staphylococcus pseudintermedius from the other closely related members of the S. intermedius group and other coagulase-positive staphylococci isolated from animals. Genetic diversity of S. pseudintermedius strains was analyzed by staphylococcal protein A-encoding gene (spa) typing. Multiplex PCR method was used to identify staphylococcal cassette chromosome mec (SCCmec) type in mecA-positive strains. All isolates previously identified as S. intermedius were shown to belong to S. pseudintermedius. According to PCR-based SCCmec typing, SCCmecIII was the most prevalent type (n = 23), and solely seven isolates were designated as non-typeable. Furthermore, the assessment of spa-typing results revealed that the majority of all strains (n = 27) harbored spa type t02, and 17 strains were classified as non-typeable.
Heß, Stefanie; Gallert, Claudia
Tolerance of antibiotic susceptible and antibiotic resistant Escherichia coli, Enterococcus and Staphylococcus strains from clinical and wastewater samples against ozone was tested to investigate if ozone, a strong oxidant applied for advanced wastewater treatment, will affect the release of antibiotic resistant bacteria into the aquatic environment. For this purpose, the resistance pattern against antibiotics of the mentioned isolates and their survival after exposure to 4 mg/L ozone was determined. Antibiotic resistance (AR) of the isolates was not correlating with higher tolerance against ozone. Except for ampicillin resistant E. coli strains, which showed a trend towards increased resistance, E. coli strains that were also resistant against cotrimoxazol, ciprofloxacin or a combination of the three antibiotics were similarly or less resistant against ozone than antibiotic sensitive strains. Pigment-producing Enterococcus casseliflavus and Staphylococcus aureus seemed to be more resistant against ozone than non-pigmented species of these genera. Furthermore, aggregation or biofilm formation apparently protected bacteria in subsurface layers from inactivation by ozone. The relatively large variance of tolerance against ozone may indicate that resistance to ozone inactivation most probably depends on several factors, where AR, if at all, does not play a major role.
Singh, Madhuri; Sasaki, Takashi; Morimoto, Yuh; Hishinuma, Tomomi; Hiramatsu, Keiichi
ABSTRACT The mechanisms underlying bacterial tolerance to antibiotics are unclear. A possible adaptation strategy was explored by exposure of drug-naive methicillin-susceptible Staphylococcus aureus strain FDA209P to vancomycin in vitro. Strains surviving vancomycin treatment (vancomycin survivor strains), which appeared after 96 h of exposure, were slow-growing derivatives of the parent strain. Although the vancomycin MICs for the survivor strains were within the susceptible range, the cytokilling effects of vancomycin at 20-fold the MIC were significantly lower for the survivor strains than for the parent strain. Whole-genome sequencing demonstrated that ileS, encoding isoleucyl-tRNA synthetase (IleRS), was mutated in two of the three vancomycin survivor strains. The IleRS Y723H mutation is located close to the isoleucyl-tRNA contact site and potentially affects the affinity of IleRS binding to isoleucyl-tRNA, thereby inhibiting protein synthesis and leading to vancomycin tolerance. Introduction of the mutation encoding IleRS Y723H into FDA209P by allelic replacement successfully transferred the vancomycin tolerance phenotype. We have identified mutation of ileS to be one of the bona fide genetic events leading to the acquisition of vancomycin tolerance in S. aureus, potentially acting via inhibition of the function of IleRS. PMID:27855063
Background The emergence of multidrug-resistant bacteria is a world health problem. Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA) strains, is one of the most important human pathogens associated with hospital and community-acquired infections. The aim of this work was to evaluate the antibacterial activity of a Pseudomonas aeruginosa-derived compound against MRSA strains. Methods Thirty clinical MRSA strains were isolated, and three standard MRSA strains were evaluated. The extracellular compounds were purified by vacuum liquid chromatography. Evaluation of antibacterial activity was performed by agar diffusion technique, determination of the minimal inhibitory concentration, curve of growth and viability and scanning electron microscopy. Interaction of an extracellular compound with silver nanoparticle was studied to evaluate antibacterial effect. Results The F3 (ethyl acetate) and F3d (dichloromethane- ethyl acetate) fractions demonstrated antibacterial activity against the MRSA strains. Phenazine-1-carboxamide was identified and purified from the F3d fraction and demonstrated slight antibacterial activity against MRSA, and synergic effect when combined with silver nanoparticles produced by Fusarium oxysporum. Organohalogen compound was purified from this fraction showing high antibacterial effect. Using scanning electron microscopy, we show that the F3d fraction caused morphological changes to the cell wall of the MRSA strains. Conclusions These results suggest that P. aeruginosa-produced compounds such as phenazines have inhibitory effects against MRSA and may be a good alternative treatment to control infections caused by MRSA. PMID:23773484
Nan, Wenlong; Tan, Pengfei; Wang, Yong; Xu, Zouliang; Mao, Kairong; Peng, Daxin; Chen, Yiping
Immunisation with attenuated Brucella spp. vaccines prevents brucellosis, but may also interfere with diagnosis. In this study, a duplex PCR was developed to distinguish Brucella suis vaccine strain S2 from field strains of B. suis biovar 1 and other Brucella spp. The PCR detected 60 fg genomic DNA of B. suis S2 or biovar 1 field strains and was able to distinguish B. suis S2 and wild-type strains of B. suis biovar 1 among 76 field isolates representing all the common species and biovars, as well as four vaccine strains, of Brucella.
Ramón-Peréz, Miriam L; Diaz-Cedillo, Francisco; Ibarra, J Antonio; Torales-Cardeña, Azael; Rodríguez-Martínez, Sandra; Jan-Roblero, Janet; Cancino-Diaz, Mario E; Cancino-Diaz, Juan C
Biofilm formation on medical and surgical devices is a major virulence determinant for Staphylococcus epidermidis. The bacterium S. epidermidis is able to produce biofilms on biotic and abiotic surfaces and is the cause of ocular infection (OI). Recent studies have shown that d-amino acids inhibit and disrupt biofilm formation in the prototype strains Bacillus subtilis NCBI3610 and Staphylococcus aureus SCO1. The effect of d-amino acids on S. epidermidis biofilm formation has yet to be tested for clinical or commensal isolates. S. epidermidis strains isolated from healthy skin (n = 3), conjunctiva (n = 9) and OI (n = 19) were treated with d-Leu, d-Tyr, d-Pro, d-Phe, d-Met or d-Ala and tested for biofilm formation. The presence of d-amino acids during biofilm formation resulted in a variety of patterns. Some strains were sensitive to all amino acids tested, while others were sensitive to one or more, and one strain was resistant to all of them when added individually; in this way d-Met inhibited most of the strains (26/31), followed by d-Phe (21/31). Additionally, the use of d-Met inhibited biofilm formation on a contact lens. The use of l-isomers caused no defect in biofilm formation in all strains tested. In contrast, when biofilms were already formed d-Met, d-Phe and d-Pro were able to disrupt it. In summary, here we demonstrated the inhibitory effect of d-amino acids on biofilm formation in S. epidermidis. Moreover, we showed, for the first time, that S. epidermidis clinical strains have a different sensitivity to these compounds during biofilm formation.
Plaut, Roger D; Mocca, Christopher P; Prabhakara, Ranjani; Merkel, Tod J; Stibitz, Scott
In vivo bioluminescent imaging permits the visualization of bacteria in live animals, allowing researchers to monitor, both temporally and spatially, the progression of infection in each animal. We sought to engineer stably luminescent clinical strains of Staphylococcus aureus, with the goal of using such strains in mouse models. The gram-positive shuttle vector pMAD was used as the backbone for an integration plasmid. A chloramphenicol resistance gene, a modified lux operon from Photorhabdus luminescens, and approximately 650 bp of homology to the chromosome of the USA300 S. aureus strain NRS384 were added, generating plasmid pRP1195. Electroporation into strain RN4220 followed by temperature shift led to integration of pRP1195 into the chromosome. The integrated plasmid was transferred to clinical strains by phage transduction. Luminescent strains displayed no in vitro growth defects. Moreover, luminescence was stable in vitro after three rounds of subculture over 48 hours of growth in the absence of antibiotics. Mice were infected with a luminescent strain of NRS384 in skin and intravenous models. In a mouse skin model, luminescent bacteria were present in lesions that formed and cleared over the course of several days, and in an intravenous model, bacteria inoculated in the mouse tail vein were observed spreading to multiple tissues. No statistically significant difference in virulence was observed between NRS384 and the luminescent strain in either infection model. These preliminary data suggest that this luminescent USA300 strain is suitable for use in mouse models. Similar strains were engineered using other sequenced clinical strains. Because these strains are stably luminescent, they should prove useful in animal models of infection.
Galdbart, J O; Allignet, J; Tung, H S; Rydèn, C; El Solh, N
Fifty-four Staphylococcus epidermidis strains responsible for infections of joint prostheses and 23 strains isolated from skin flora were studied for markers of virulence, to discriminate invasive strains from normal flora. They were screened for binding to polystyrene and matrix proteins and for the presence of staphylococcal genes involved in adhesion. The ica operon involved in biofilm formation was the only marker discriminating between these 2 categories of strains.
Pei, Dong; Hill-Clemons, Casey; Carissimo, Guillaume; Yu, Wanqin; Vernick, Kenneth D.
Here, we report the annotated draft genome sequences of two strains of Serratia spp., Ag1 and Ag2, isolated from the midgut of two different strains of Anopheles gambiae. The genomes of these two strains are almost identical. PMID:25767231
Yamazaki, Kazuko; Kato, Fuminori; Kamio, Yoshiyuki; Kaneko, Jun
Staphylococcus aureus strain Smith 5R produces a two-component pore-forming toxin and forms a rough-surfaced colony with hemolytic haloes on human red blood cell plates (R[+]). Serial subcultures of the strain in broth caused the appearance of gamma-hemolysin negative variants with a smooth colony shape (S[-]), and the S[-] valiant became predominant in culture. The R[+] strain, in which agrA is naturally disrupted by an insertion of IS1181, produced high levels of gamma-hemolysin. In the S[-] variant, expression of both hlg and lukS-F mRNAs was strongly reduced. Nucleotide sequencing of the sae locus revealed that all isolated S[-] variants had spontaneous mutations in the sae locus. Recovery of gamma-hemolysin productivity in S[-] by transformation of the wild-type sae allele strongly suggested that the expression of gamma-hemolysin is positively regulated by sae in an agr-independent manner.
Vigo, Germán B; Giacoboni, Gabriela I; Gagetti, Paula S; Pasterán, Fernando G; Corso, Alejandra C
Twenty-eight strains isolated from dog clinical samples identified as Staphylococcus pseudintermedius by mass spectrometry (MALDI-TOF) were studied to assess antimicrobial susceptibility by the diffusion method and clonal relationship by pulsed field gel electrophoresis (PFGE). Methicillin resistance (3/28 isolates; 10,7%) was evaluated by mecA PCR. Fifteen strains (53.6%) were resistant to at least one of the antibiotics tested, and eleven of them (39.3%) showed multiple resistance (3 or more antimicrobial families). Eleven isolates (39.3%) were resistant to erythromycin due to the presence of ribosomal methylase ermB, whereas clindamycin inducible resistance was not detected. Twenty-seven (27) clonal types were differentiated by PFGE, suggesting high clonal diversity. We emphasize that the finding of multiresistant S. psedintermedius strains is an emerging problem to be considered in veterinary diagnostic laboratory treatment of canine infections and in public health settings.
Blandino, Giovanna; Fazio, Davide; Petronio, Giulio Petronio; Inturri, Rosanna; Tempera, Gianna; Furneri, Pio Maria
The objective of the study was to characterize at species level by phenotypic and different molecular methods the strains of Lactobacillus spp. used as constituents of five oral and four vaginal products. Susceptibilities to representative antibiotics were evaluated. In addition, total viable counts at mid and 3 months to deadline of shelf life, in the different formulations and the presence of eventual contaminant microorganisms were investigated.In all oral products the molecular characterization at species level of the strains of Lactobacillus spp. confirmed the strains stated on the label, except for one strain cited on the label as Lactobacillus casei, that our study characterized as Lactobacillus paracasei. In oral products total viable cell content complied with content claimed on the label. In three out four vaginal products (one product claimed "bacillo di Döderlein"), molecular characterization complied with the bacterial name stated on the label. Two vaginal products reported viable counts on the label that were confirmed by our study. The other vaginal products, which did not report bacterial counts on the label, showed a similar decrease of viable counts at different dates to deadline compared to the others. From all the tested products, contaminant microorganisms and acquired resistance to representative antibiotics by the probiotic strains were not detected.
Frediani-Wolf, V; Stephan, R
The aim of this study was to determine resistance patterns of strains of Campylobacter spp. isolated from poultry carcasses in one of the two big Swiss poultry slaughterhouses. A variety of antibiotics with clinical relevance in human and/or in veterinary medicine was tested. In addition, the results of the disc diffusion method, E-test and microdilution broth methods were compared. Of the 195 Campylobacter jejuni strains isolated from 195 poultry carcasses from 21 flocks, 134 strains were susceptible in vitro to all tested antibiotics. Sixty-one strains (31.3%, from eight flocks) showed resistance. Forty-one strains were resistant to a single antibiotic-34 to streptomycin, 6 to ampicillin and 1 to ciprofloxacin. Eighteen strains (from two flocks) showed combined resistance to erythromycin and streptomycin, two strains to ciprofloxacin and streptomycin. None of the isolates was resistant to tetracycline. The data of this first study in Switzerland show a favourable resistance situation for C. jejuni strains against erythromycin, tetracycline and ciprofloxacin. The disc diffusion method was found to be a reliable and easy tool for monitoring the prevalence of resistant C. jejuni strains. For surveillance of changes in the susceptibility concentration levels to antimicrobial agents, however, a MIC method should be used. Further investigations along the whole poultry production chain (farm, slaughterhouse and retail levels) are now necessary in order to confirm the resistance situation.
Kérouanton, A; Hennekinne, J A; Letertre, C; Petit, L; Chesneau, O; Brisabois, A; De Buyser, M L
Enterotoxins produced by Staphylococcus aureus are responsible for staphylococcal food-poisoning outbreaks (SFPO). In France, SFPO are the second cause of food-borne diseases after Salmonella. However, very little is known about the strains involved. The objective of this study was to characterize the staphylococcal strains related to these SFPO through phenotypic and genotypic analyses. A total of 178 coagulase-positive staphylococcal isolates recovered from 31 SFPO (1981-2002) were screened through biotyping. Thirty-three strains representative of the different biotypes in each SFPO were further examined for SmaI macrorestriction-type, phage-type, resistance to various antimicrobial drugs, presence of staphylococcal enterotoxin (se) genes sea to sei, and production of enterotoxins SEA to SED. All these 33 strains were identified as S. aureus species: 27 were of human biotypes and six ovine or non-host-specific biotypes. Most (74.1%) strains reacted with group III phages. Eleven strains were resistant to at least two classes of antibiotics and among them, two were resistant to methicillin. Twenty-nine strains carried one or several of the eight se genes tested; the gene sea was most common (n=23), and often linked to sed (n=12) or seh (n=5). The novel se genes seg-i were in all cases associated with se genes sea to sed except for one strain which carried only seg and sei. Pulsed-Field Gel Electrophoresis (PFGE) of SmaI macrorestriction digests of the 33 strains discriminated 32 PFGE patterns grouped into nine biotype-specific clusters. All five strains carrying sea and seh were grouped together into the same sub-cluster. Three of the four se-gene-negative strains were in one PFGE cluster: all four should be tested for se genes not included in this study and, if negative, be further investigated for the presence of unidentified SEs.
Rall, V L M; Vieira, F P; Rall, R; Vieitis, R L; Fernandes, A; Candeias, J M G; Cardoso, K F G; Araújo, J P
Milk is considered a nutritious food because it contains several important nutrients including proteins and vitamins. Conversely, it can be a vehicle for several pathogenic bacteria such as Staphylococcus aureus. This study aimed to analyze the frequency of genes encoding the staphylococcal enterotoxins (SEs) SEA, SEB, SEC, SED, SEE, SEG, SEH, SEI and SEJ in S. aureus strains isolated from raw or pasteurized bovine milk. S. aureus was found in 38 (70.4%) out of 54 raw milk samples at concentrations of up to 8.9 x 10(5) CFU/ml. This microorganism was present in eight samples of pasteurized milk before the expiration date and in 11 samples analyzed on the expiration date. Of the 57 strains studied, 68.4% were positive for one or more genes encoding the enterotoxins, and 12 different genotypes were identified. The gene coding for enterotoxin A, sea, was the most frequent (16 strains, 41%), followed by sec (8 strains, 20.5%), sed (5 strains, 12.8%), seb (3 strains, 7.7%) and see (2 strains, 5.1%). Among the genes encoding the other enterotoxins, seg was the most frequently observed (11 strains, 28.2%), followed by sei (10 strains) and seh and sej (3 strains each). With the recent identification of new SEs, the perceived frequency of enterotoxigenic strains has increased, suggesting that the pathogenic potential of staphylococci may be higher than previously thought; however, further studies are required to assess the expression of these new SEs by S. aureus, and their impact in foodborne disease. The quality of Brazilian milk is still low, and efforts from the government and the entire productive chain are required to attain consumer safety.
Donnio, Pierre-Yves; Février, Frédéric; Bifani, Pablo; Dehem, Marie; Kervégant, Christèle; Wilhelm, Nathalie; Gautier-Lerestif, Anne-Lise; Lafforgue, Nathalie; Cormier, Michel; Le Coustumier, Alain
The excision of the staphylococcal chromosomal cassette mec (SCCmec) from methicillin-resistant Staphylococcus aureus (MRSA) strains results in methicillin-susceptible S. aureus (MSSA) strains. In order to determine the proportion and diversity of multidrug-resistant MSSA (MR-MSSA) strains derived from MRSA strains, 247 mecA-negative isolates recovered in 60 French hospitals between 2002 and 2004 were characterized. The spa types of all strains were determined, and a subset of the strains (n = 30) was further genotyped by multilocus sequence typing. The IDI-MRSA assay was used to test the isolates for the presence of the SCCmec element, which was detected in 68% of all isolates analyzed. Molecular analysis of the samples suggested that 92% of the MR-MSSA isolates were derived from MRSA clones of diverse genetic backgrounds, of which the clone of sequence type 8 and SCCmec type IV(A) accounted for most of the samples. High variations in incidence data and differences in the molecular characteristics of the isolates from one hospital to another indicate that the emergence of MR-MSSA resulted from independent SCCmec excisions from epidemic MRSA isolates, as well as the diffusion of methicillin-susceptible strains after the loss of SCCmec. MR-MSSA could constitute a useful model for the study of the respective genetic and environmental factors involved in the dissemination of S. aureus in hospitals.
Gonano, M; Hein, I; Zangerl, P; Rammelmayr, A; Wagner, M
Austrian veterinary (n=91), dairy (n=86), and human strains (n=48) of Staphylococcus aureus were tested for various phenotypic properties including clumping factor, egg-yolk reaction, production of thermonuclease and susceptibility to 14 antibiotics. In addition the expression of enterotoxins (A-E), and the presence of enterotoxin genes sea to sej and tst was determined. Significant differences in antimicrobial susceptibility were found with 84.6% of veterinary, 57.0% of dairy, and 20.8% of human strains susceptible to all antibiotics tested (P<0.0005). More human strains produced enterotoxins (41.7%) than veterinary (9.9%) and dairy strains (12.6%) while 40.7% and 38.5% of veterinary, 47.7% and 52.3% of dairy, and 77.1% and 87.5% of human strains were se- and tst-positive, respectively. AFLP analysis revealed nine clusters with over- or under-representation of strains with specific characteristics. Strains clustered according to origin (veterinary, dairy, and human) and/or presence of toxin genes and antimicrobial resistance.
Brom, Susana; Martinez, Esperanza; Dávila, Guillermo; Palacios, Rafael
Agrobacterium transconjugants containing symbiotic plasmids from different Rhizobium spp. strains that nodulate Phaseolus vulgaris were obtained. All transconjugants conserved the parental nodulation host range. Symbiotic (Sym) plasmids of Rhizobium strains isolated originally from P. vulgaris nodules, which had a broad nodulation host range, and single-copy nitrogenase genes conferred a Fix+ phenotype to the Agrobacterium transconjugants. A Fix− phenotype was obtained with Sym plasmids of strains isolated from P. vulgaris nodules that had a narrow host range and reiterated nif genes, as well as with Sym plasmids of strains isolated from other legumes that presented single nif genes and a broad nodulation host range. This indicates that different types of Sym plasmids can confer the ability to establish an effective symbiosis with P. vulgaris. Images PMID:16347637
A strain of Staphylococcus aureus was isolated, the growth of which in the presence of neutral red was inhibited by sunlight. This phenomenon was not shown by any of a number of other strains of the same or different genera. Images PMID:4854783
Chan, Kok-Gan; Sulaiman, Joanita; Yong, Delicia Ann; Tee, Kok Keng; Yin, Wai-Fong; Priya, Kumutha
Staphylococcus saprophyticus strain SU8 was isolated from a pristine water source in Malaysia and it exhibited degradation of N-hexanoylhomoserine lactone. Here we report the draft genome sequence of S. saprophyticus strain SU8 to further understand its quorum quenching abilities.
MRS926 is a livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) strain of sequence type (ST) 398. In order to facilitate in vitro and in vivo studies of this strain, we sought to tag it with a fluorescent marker. We cloned a codon-optimized gene for TurboGFP into a shuttle vector...
Hardy, Katherine J; Oppenheim, Beryl A; Gossain, Savita; Gao, Fang; Hawkey, Peter M
Staphylococcal interspersed repeat unit typing has previously been shown to have the ability to discriminate between epidemic methicillin-resistant Staphylococcus aureus strains in the United Kingdom. The current study illustrates its ability to distinguish between strains within an endemic setting thereby providing a rapid transportable typing method for the identification of transmission events.
Bakthavatchalam, Yamuna Devi; Peter, John Victor; Rajinikanth, Janakiraman; Inbanathan, Francis Yesurajan; Devanga Ragupathi, Naveen Kumar; Rajamani Sekar, Suresh Kumar
We report here the draft genome sequences of 11 heteroresistant vancomycin-intermediate Staphylococcus aureus (hVISA) strains from bloodstream infection. All strains harbor mutations in vraSR, graSR, walKR, and/or tcaRAB and are often implicated as the frequently mutated candidate genes in hVISA phenotypes. PMID:28007859
Snel, Gustavo G M; Monecke, Stefan; Ehricht, Ralf; Piccinini, Renata
The biofilm-associated protein (Bap) of Staphylococcus aureus is a high molecular weight cell-wall-anchored protein involved in biofilm formation, first described in bovine mastitis strains from Spain. So far, studies regarding Bap were mainly based on the Spanish strain V329 and its mutants, but no information on the genetic variability of bap-positive Staph. aureus strains is yet available in the literature. The present study investigated the molecular characteristics of 8 bap-positive Staph. aureus strains from subclinical bovine mastitis, isolated in 5 herds; somatic cell counts (SCC) of milk samples were also registered. Strains were characterised using MLST, SPA typing and microarray and the results were compared with V329. All isolates from this study and V329 were assigned to ST126, t605, but some molecular differences were observed. Only herd A and B strains harboured the genes for β-lactams resistance; the leukocidin D/E gene, a type I site-specific deoxyribonuclease subunit, 3rd locus gene and serin-protease A and B were carried by all strains, but not by V329, while serin-protease E was absent in V329 and in another isolate. Four isolates and V329 harboured the fibronectin-binding protein B gene. SCC showed the highest value in the milk sample affected by the only strain carrying all the virulence factors considered. Potential large variability of virulence was evidenced among V329 and all bap-positive Staph. aureus strains considered: the carriage of fnb could enhance the accumulation of biofilm, but the lack of lukD/E and splA, B or E might decrease the invasiveness of strain.
Jacobs, S. I.; Willis, A. T.
Five hundred and fifty-two strains of Staphylococcus aureus of hospital origin were resistant to penicillin, streptomycin, and tetracycline. Of these, 298 were also resistant to neomycin and kanamycin, and this resistance was related to pigment production on glycerol monoacetate agar, the production of β-lysin, the absence of fibrinolytic and proteolytic activity, and to phage susceptibility. The use of physiological markers, the inadequacy of phage typing, and the possible reasons for the emergence of neomycin-resistant staphylococci are discussed. PMID:14227429
Rosenberg Goldstein, Rachel E.; Micallef, Shirley A.; Gibbs, Shawn G.; He, Xin; George, Ashish; Sapkota, Amir; Joseph, Sam W.; Sapkota, Amy R.
As reclaimed water use expands, it is important to evaluate potential occupational health risks from exposure to this alternative water source. We compared odds of colonization with methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible S. aureus (MSSA), vancomycin-resistant enterococci (VRE), and vancomycin-susceptible enterococci (VSE) between spray irrigation workers using reclaimed water and office worker controls. Nasal and dermal swabs from 19 spray irrigation workers and 24 office worker controls were collected and analyzed for MRSA, MSSA, VRE, and VSE. Isolates were confirmed using standard biochemical tests and polymerase chain reaction assays. Antimicrobial susceptibility testing was performed by Sensititre® microbroth dilution. Data were analyzed by two-sample proportion, chi-square, Fisher’s exact tests, and logistic regression. No MRSA or VRE were detected in any samples. MSSA was detected in 26% and 29% of spray irrigators and controls, respectively. VSE was detected in 11% and 0% of spray irrigation workers and controls, respectively. The adjusted odds of MSSA, multidrug-resistant MSSA, and either MSSA or VSE colonization were greater among spray irrigation workers, however results were not statistically significant. Future studies with larger sample sizes are needed to further evaluate this relationship. PMID:24747541
Cernohorská, L; Votava, M
Eighty-seven Staphylococcus saprophyticus strains isolated from urine of 87 patients with cystitis were examined in 2005-2009. All strains were tested for resistance to vancomycin, nitrofurantoin, doxycycline, oxacillin, amoxicillin/clavulanate, cefoxitin and sulfamethoxazole/trimethoprim and for biofilm formation by a modified Christensen method. None of the tested strains of S. saprophyticus showed resistance to vancomycin, while 2 strains (2.3 %) were resistant to nitrofurantoin, 9 (10.3%) to doxycycline, 20 (23.0 %) to oxacillin, 6 (6.9%) to amoxicillin/clavulanate, 6 (6.9%) to cefoxitin and 1 (1.1%) to sulfamethoxazole/trimethoprim. S. saprophyticus was detected as the causative agent of cystitis in 0.4 % of 20,375 culture positive urine samples analyzed in our laboratory between 2005 and 2009. Most 67 (77.0%) S. saprophyticus strains were recovered from women, particularly from young women. Biofilm formation was detected in 16 (18.4 %) out of 87 S. saprophyticus strains.
Sharifi-Rad, J; Hoseini Alfatemi, SM; Sharifi Rad, M; Iriti, M
Background: Today, the commonly used antibiotics may more and more frequently be ineffective against multiple pathogens, due to the selection of resistant microbial strains. As a result, an effort to find a new approach for solving this issue has been considered. Aim: The aim of this study is to investigate antimicrobial properties of allicin, silver nanoparticles (Ag NPs) and their combination again skin infection caused by methicillin-resistant Staphylococcus aureus (MRSA) strains in an animal model. Materials and Methods: In vivo, the effects of allicin, Ag NPs and their combination were investigated on mice in which the skin infection was caused by MRSA strains. In animals, S. aureus colony-forming units (CFU)/mL were counted the 4th day after treatment. In vitro, minimum inhibitory concentration (MIC) of bacterial growth and minimum bactericidal concentration (MBC) of allicin, Ag NPs and their combination were determined by microdilution technique. Results: The results of in vitro assays showed that MIC of allicin and Ag NPs were 2.2 mg/mL and 5.6 mg/mL, respectively, and MBC of allicin and Ag NPs were 3.1 ppm and 7.5 ppm, respectively. However, MIC and MBC of allicin and Ag NPs together on MRSA strains were 0.4 mg/mL and 1.1 ppm, respectively. The results of in vivo tests on skin infection showed that bacteria counted for control, Ag NPs, allicin and their combination were 377 × 108, 80 × 106, 43 × 105, and 0 CFU/mL, respectively. Conclusion: The obtained results clearly indicated (for the first time, to the best of our knowledge) that allicin and Ag NPs, when used in combination, exhibited a synergistic activity. Therefore, the present results can be of interest in the future to improve the treatment of skin infections caused by MRSA strains. PMID:25506477
Bosi, Emanuele; Monk, Jonathan M.; Aziz, Ramy K.; Fondi, Marco; Nizet, Victor; Palsson, Bernhard Ø.
Staphylococcus aureus is a preeminent bacterial pathogen capable of colonizing diverse ecological niches within its human host. We describe here the pangenome of S. aureus based on analysis of genome sequences from 64 strains of S. aureus spanning a range of ecological niches, host types, and antibiotic resistance profiles. Based on this set, S. aureus is expected to have an open pangenome composed of 7,411 genes and a core genome composed of 1,441 genes. Metabolism was highly conserved in this core genome; however, differences were identified in amino acid and nucleotide biosynthesis pathways between the strains. Genome-scale models (GEMs) of metabolism were constructed for the 64 strains of S. aureus. These GEMs enabled a systems approach to characterizing the core metabolic and panmetabolic capabilities of the S. aureus species. All models were predicted to be auxotrophic for the vitamins niacin (vitamin B3) and thiamin (vitamin B1), whereas strain-specific auxotrophies were predicted for riboflavin (vitamin B2), guanosine, leucine, methionine, and cysteine, among others. GEMs were used to systematically analyze growth capabilities in more than 300 different growth-supporting environments. The results identified metabolic capabilities linked to pathogenic traits and virulence acquisitions. Such traits can be used to differentiate strains responsible for mild vs. severe infections and preference for hosts (e.g., animals vs. humans). Genome-scale analysis of multiple strains of a species can thus be used to identify metabolic determinants of virulence and increase our understanding of why certain strains of this deadly pathogen have spread rapidly throughout the world. PMID:27286824
Larsen, Nadja; Thorsen, Line; Kpikpi, Elmer Nayra; Stuer-Lauridsen, Birgitte; Cantor, Mette Dines; Nielsen, Bea; Brockmann, Elke; Derkx, Patrick M F; Jespersen, Lene
Bacillus spp. are commonly used as probiotic species in the feed industry, however, their benefits need to be confirmed. This study describes a high throughput screening combined with the detailed characterization of endospore-forming bacteria with the aim to identify new Bacillus spp. strains for use as probiotic additives in pig feed. A total of 245 bacterial isolates derived from African fermented food, feces and soil were identified by 16S rRNA gene sequencing and screened for antimicrobial activity and growth in the presence of antibiotics, bile salts and at pH 4.0. Thirty-three Bacillus spp. isolates with the best characteristics were identified by gyrB and rpoB gene sequencing as B. amyloliquefaciens subsp. plantarum, B. amyloliquefaciens subsp. amyloliquefaciens, B. subtilis subsp. subtilis, B. licheniformis, B. mojavensis, B. pumilus and B. megaterium. These isolates were further investigated for their activity against the pathogenic bacteria, antibiotic susceptibility, sporulation rates, biofilm formation and production of glycosyl hydrolytic enzymes. Additionally, ten selected isolates were assessed for heat resistance of spores and the effect on porcine epithelial cells IPEC-J2. Isolates of B. amyloliquefaciens, B. subtilis and B. mojavensis, showed the best overall characteristics and, therefore, potential for usage as probiotic additives in feed. A large number of taxonomically diverse strains made it possible to reveal species and subspecies-specific trends, contributing to our understanding of the probiotic potential of Bacillus species.
Rocha, Ticiana Silva; Baptista, Ana Angelita Sampaio; Donato, Tais Cremasco; Milbradt, Elisane Lenita; Okamoto, Adriano Sakai; Andreatti Filho, Raphael Lucio
In the aviculture industry, the use of Lactobacillus spp. as a probiotic has been shown to be frequent and satisfactory, both in improving bird production indexes and in protecting intestine against colonization by pathogenic bacteria. Adhesion is an important characteristic in selecting Lactobacillus probiotic strains since it impedes its immediate elimination to enable its beneficial action in the host. This study aimed to isolate, identify and characterize the in vitro and in vivo adhesion of Lactobacillus strains isolated from birds. The Lactobacillus spp. was identified by PCR and sequencing and the strains and its adhesion evaluated in vitro via BMM cell matrix and in vivo by inoculation in one-day-old birds. Duodenum, jejunum, ileum and cecum were collected one, four, 12 and 24 h after inoculation. The findings demonstrate greater adhesion of strains in the cecum and an important correlation between in vitro and in vivo results. It was concluded that BMM utilization represents an important technique for triage of Lactobacillus for subsequent in vivo evaluation, which was shown to be efficient in identifying bacterial adhesion to the enteric tract.
Rocha, Ticiana Silva; Baptista, Ana Angelita Sampaio; Donato, Tais Cremasco; Milbradt, Elisane Lenita; Okamoto, Adriano Sakai; Filho, Raphael Lucio Andreatti
In the aviculture industry, the use of Lactobacillus spp. as a probiotic has been shown to be frequent and satisfactory, both in improving bird production indexes and in protecting intestine against colonization by pathogenic bacteria. Adhesion is an important characteristic in selecting Lactobacillus probiotic strains since it impedes its immediate elimination to enable its beneficial action in the host. This study aimed to isolate, identify and characterize the in vitro and in vivo adhesion of Lactobacillus strains isolated from birds. The Lactobacillus spp. was identified by PCR and sequencing and the strains and its adhesion evaluated in vitro via BMM cell matrix and in vivo by inoculation in one-day-old birds. Duodenum, jejunum, ileum and cecum were collected one, four, 12 and 24 h after inoculation. The findings demonstrate greater adhesion of strains in the cecum and an important correlation between in vitro and in vivo results. It was concluded that BMM utilization represents an important technique for triage of Lactobacillus for subsequent in vivo evaluation, which was shown to be efficient in identifying bacterial adhesion to the enteric tract. PMID:25477944
Grune Loffler, Sylvia; Passaro, Diego; Samartino, Luis; Soncini, Analía; Romero, Graciela; Brihuega, Bibiana
Leptospirosis is an infectious disease of wide global distribution, which is endemic in Argentina. The objective of this study was to obtain the genetic profiles of Leptospira spp. strains isolated from clinical cases of dogs in the province of Buenos Aires by the multiple-locus variable-number tandem repeat analysis (MLVA). Eight isolated canine strains were genotyped by MLVA, obtaining the identical profile of Leptospira interrogans serovar Canicola Hond Utrecht IV in the strains named Dogy and Mayo. The strains named Bel, Sarmiento, La Plata 4581 and La Plata 5478 were identical to the profile of the genotype of L. interrogans serovar Portlandvere MY 1039.The strain named Avellaneda was identical to the genotype profile of L. interrogans serovar Icterohaemorrhagiae RGA and the strain named SB had the same profile as the L. interrogans serovar Pomona Baires genotype and was similar to the profile of serovar Pomona Pomona genotype. It would be useful to include a larger number of isolates from different dog populations in various provinces of Argentina and to characterize the genetic profiles of the strains circulating in the country. The information obtained will be useful for the control of leptospirosis in the dog population.
Moniri, R; Farahani, R Kheltabadi; Shajari, Gh; Shirazi, MH. Nazem; Ghasemi, A
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
Vindel, A.; Martín-Bourgon, C.; Saez-Nieto, J. A.
A high percentage of non-typable (NT) Staphylococcus aureus strains was isolated in Spanish hospitals during 1984 and 1985. Several alternative methods of typing were employed to study these isolates. These were: phage-typing at 1000 X RTD, phage-typing after heat-treatment (48 degrees C), thermal shock (56 degrees C), reverse-typing and induction of additional phages. Using these methods the number of NT isolates was reduced by 60%. Best results were obtained with heat-treatment. Additional phages and reverse-typing were also useful. A scheme for the study of outbreaks and sporadic cases caused by NT strains is proposed using the methods described. PMID:3609172
Marín, P; Escudero, E; Fernández-Varón, E; Cárceles, C M; Corrales, J C; Gómez-Martín, A; Martínez, I
The antibiotic susceptibility of 32 strains of Staphylococcus aureus isolated from the mastitic milk of dairy goats was evaluated. The antibiotics tested were 3 fluoroquinolones that have been developed especially for use in veterinary medicine: danofloxacin, marbofloxacin, and orbifloxacin. Minimum inhibitory concentration (MIC) tests were performed according to the microdilution broth method. The MIC(90) (concentration at which 90% inhibition is achieved) values obtained were 0.5, 1, and 1 mg/L for danofloxacin, marbofloxacin, and orbifloxacin, respectively. Danofloxacin was the most active fluoroquinolone tested against Staph. aureus strains isolated from milk; however, specific testing is required before using these drugs as therapy for the control of clinical mammary infections in goats.
Lyon, B R; May, J W; Skurray, R A
Nosocomial infections caused by Staphylococcus aureus strains resistant to methicillin and multiple antibiotics have reached epidemic proportions in Melbourne, Australia, over the past 5 years. Plasmid analysis of representative clinical isolates demonstrated the presence of three classes of plasmid DNA in most strains. Resistance to gentamicin, kanamycin, and tobramycin was usually mediated by an 18-megadalton plasmid but could also be encoded by a related 22-megadalton plasmid. Two distinguishable plasmids of 3 megadaltons each endowed resistance to chloramphenicol, and the third class consisted of small plasmids, each approximately 1 megadalton in size, with no attributable function. An extensive array of resistance determinants, including some which have usually been associated with a plasmid locus, were found to exist on the chromosome. Evidence that resistance to gentamicin, kanamycin, and tobramycin is chromosomally encoded in some clinical isolates suggests that this determinant may have undergone genetic translocation onto the staphylococcal chromosome. Images PMID:6311086
Köten, Bente; Becker, Karsten; Podschun, Rainer; von Eiff, Christof; Meyer-Hoffert, Ulf; Harder, Jürgen; Gläser, Regine
Staphylococcus aureus is a major human pathogen causing cutaneous infections to life-threatening bacteremia. These infections are often caused by strains derived from the own microflora suggesting that a disturbed epidermal barrier may promote invasion of S. aureus. Antimicrobial peptides and proteins (AMP) such as human beta-defensin-3 and RNase 7 contribute to control the colonization of S. aureus on the skin surface. This leads to the hypothesis that strains with a decreased susceptibility toward skin-derived AMP may better overcome the innate cutaneous defence barrier increasing the possibility of invading into the blood stream. To address this hypothesis we determined whether S. aureus strains from bacteremia patients are less susceptible to various skin-derived AMP than strains from healthy carriers. No differences in the AMP-killing activity against bacteremia-derived S. aureus and control strains were detected suggesting that the onset of S. aureus bacteremia is not based on the varying susceptibilities against skin-derived AMP.
Růžičková, Vladislava; Pantůček, Roman; Petráš, Petr; Machová, Ivana; Kostýlková, Karla; Doškař, Jiří
One hundred and twenty-seven exfoliative toxin-producing (ET-positive) strains of Staphylococcus aureus collected in 23 Czech and one Slovak maternity hospitals from 1998 to 2011 were genotypically characterized by multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE) profiling, spa gene polymorphism analysis, and ETA-converting prophage carriage, which resulted in the identification of 21 genotypes grouped into 4 clonal complexes (CC). Ninety-one isolates carried the eta gene alone whilst 12 isolates harboured only the etb gene. Two new, to date not defined, spa types (t6644 and t6645) and 2 novel sequence types (ST2194 and ST2195) were identified in the set of strains under study. The predominant CC121 occurred in 13 Czech hospitals. CC15, CC9, and ST88 (CC88) exclusively included eta gene-positive strains while the strains belonging to ST121 harboured the eta and/or etb genes. This study highlights not only significant genomic diversity among impetigo strains and the distribution of major genotypes disseminated in the Czech and Slovak maternity hospitals, but also reveals their impact in epidermolytic infections.
Zhi, Yan; Wu, Qun; Du, Hai; Xu, Yan
Streptomyces spp. producing geosmin have been regarded as the most frequent and serious microbial contamination causing earthy off-flavor in Chinese liquor. It is therefore necessary to control the Streptomyces community during liquor fermentation. Biological control, using the native microbiota present in liquor making, appears to be a better solution than chemical methods. The objective of this study was to isolate native microbiota antagonistic toward Streptomyces spp. and then to evaluate the possible action mode of the antagonists. Fourteen Bacillus strains isolated from different Daqu (the fermentation starter) showed antagonistic activity against Streptomyces sampsonii, which is one of the dominant geosmin producers. Bacillus subtilis 2-16 and Bacillus amyloliquefaciens 1-45 from Maotai Daqu significantly inhibited the growth of S. sampsonii by 57.8% and 84.3% respectively, and effectively prevented the geosmin production in the simulated fermentation experiments (inoculation ratio 1:1). To probe the biocontrol mode, the ability of strain 2-16 and 1-45 to produce antimicrobial metabolites and to reduce geosmin in the fermentation system was investigated. Antimicrobial substances were identified as lipopeptides by ultra-performance liquid chromatography tandem electrospray ionization/quadrupole-time-of-flight mass spectrometry (UPLC-ESI/Q-TOF MS) and in vitro antibiotic assay. In addition, strains 2-16 and 1-45 were able to remove 45% and 15% of the geosmin respectively in the simulated solid-state fermentation. This study highlighted the potential of biocontrol, and how the use of native Bacillus species in Daqu could provide an eco-friendly method to prevent growth of Streptomyces spp. and geosmin contamination in Chinese liquor fermentation.
Soll, D R; Galask, R; Schmid, J; Hanna, C; Mac, K; Morrow, B
Candida spp. carriage and strain relatedness were assessed in 52 healthy women at 17 anatomical locations by using an isolation procedure which assesses carriage intensity and by using a computer-assisted DNA fingerprinting system which computes genetic similarity between strains on the basis of the patterns of Southern blots probed with the moderately repetitive sequence Ca3. Candida spp. were cultured from 73% of the test individuals, most frequently from the oral (56%), vulvovaginal (40%), and anorectal (24%) regions. Half of the test individuals with Candida spp. carried the organism simultaneously in more than one of the three general areas of carriage. Isolates from different body locations of the same individual were either completely unrelated, identical, or highly similar but nonidentical. In 11 cases in which Candida spp. were simultaneously isolated from the oral cavity and vaginal canal, seven pairs of isolates were genetically unrelated and four pairs were similar but nonidentical. In the latter cases, the isolate pairs each appear to have arisen by genetic divergence from a single progenitor. A comparison of the genetic relatedness of isolates from different individuals further uncovered a single strain which was vaginospecific in the Iowa City, Iowa area and reduced genetic diversity among vulvovaginal strains compared with those isolated from other body locations. These results suggest that strains adapt to different anatomical locations and, conversely, that in a healthy individual there is anatomical selection of vaginotropic, anotropic and orotropic strains of Candida spp. Images PMID:1761692
Bückle Née Müller, Anne; Kranz, Markus; Schmidt, Herbert; Weiss, Agnes
The species Staphylococcus carnosus is a non-pathogenic representative of the coagulase negative staphylococci. Specific strains are applied as meat starter cultures. The species consists of two subspecies, S. carnosus ssp. carnosus and S. carnosus ssp. utilis. In order to place S. carnosus strains, characterized in former studies, in a genetic background that allows a typing of candidates for starter cultures, a Multilocus Sequence Typing (MLST) scheme was developed. Internal fragments of the genes tpiA, xprT, dat, gmk, glpK, narG, cstA, encoding triosephosphate isomerase, xanthine phosphoribosyltransferase, d-amino acid aminotransferase, guanylate kinase, glycerol kinase, the α-chain of the respiratory nitrate reductase, and a carbon starvation protein where chosen. Genes were selected based on their equal distribution in the genome, taxonomic value in subspecies differentiation and metabolic function. This MLST was applied to 44 S. carnosus strains, most of them previously analyzed for their suitability as starter cultures. The number of alleles varied between zero (tpiA) and five (cstA) and allowed the definition of nine sequence types (ST). ST1 was most abundant (18 strains), followed by ST2 (8) and ST4 (6). The nine STs confirmed a close relationship of all strains despite their isolation source and year, but lacked correlation with physiological activities relevant for starter cultures. The low amount of STs in the strain set lets us suggest that recombination between strains is rare. Thus, it is hypothesized that evolutionary events seem to be due to single point mutations rather than intrachromosomal recombination, and that the species possesses a clonal population structure.
Zhang, Haifang; Zheng, Yi; Gao, Huasheng; Xu, Ping; Wang, Min; Li, Aiqing; Miao, Minhui; Xie, Xiaofang; Deng, Yimai; Zhou, Huiqin; Du, Hong
Staphylococcus aureus is a common pathogen causing both hospital and community-acquired infections. Hemolysin is one of the important virulence factors for S. aureus and causes the typical β-hemolytic phenotype which is called complete hemolytic phenotype as well. Recently, S. aureus with an incomplete hemolytic phenotype (SIHP) was isolated from clinical samples. To study the microbiologic characteristics of SIHP, the special hemolytic phenotype of SIHP was verified on the sheep blood agar plates supplied by different manufacturers. Expression of hemolysin genes hla, hlb, hlgC, and hld of SIHP was detected by qRT-PCR and it was showed that expression of hlb in SIHP was obviously increased compared to the control S. aureus strains with complete hemolytic phenotype (SCHP), while the expression of hla, hlgC, and hld in SIHP was significantly decreased. In addition, the α-hemolysin encoded by gene hla was decreased obviously in SIHP compared to SCHP by western blot. All 60 SIHP strains were identified to be the methicillin resistant S. aureus (MRSA), and moreover these SIHP strains all contains mecA gene. The virulence gene tst were all present in SIHP, and the intracellular survival ability of SIHP was much greater than that of the gene tst negative S. aureus. We also found that IL-2, IL-6, and IL-17A secreted in the supernatant of SIHP infected macrophages increased significantly compared to tst negative control strains infected ones. MLST analysis showed that all of SIHP strains were classified into ST5 clone. To our knowledge, this study firstly showed that SIHP strains are a kind of methicillin resistant strains which express β-hemolysin highly and possess a potential high virulence, and it was suggested that SIHP should be paid more attention in hospital. PMID:27917374
Guadarrama-Mendoza, P.C.; del Toro, G. Valencia; Ramírez-Carrillo, R.; Robles-Martínez, F.; Yáñez-Fernández, J.; Garín-Aguilar, M.E.; Hernández, C.G.; Bravo-Villa, G.
Two native Pleurotus spp. strains (white LB-050 and pale pink LB-051) were isolated from rotten tree trunks of cazahuate (Ipomoea murucoides) from the Mexican Mixtec Region. Both strains were chemically dedikaryotized to obtain their symmetrical monokaryotic components (neohaplonts). This was achieved employing homogenization time periods from 60 to 65 s, and 3 day incubation at 28 °C in a peptone-glucose solution (PGS). Pairing of compatible neohaplonts resulted in 56 hybrid strains which were classified into the four following hybrid types: (R1-nxB1-n, R1-nxB2-1, R2-nxB1-n and R2-nxB2-1). The mycelial growth of Pleurotus spp. monokaryotic and dikaryotic strains showed differences in texture (cottony or floccose), growth (scarce, regular or abundant), density (high, regular or low), and pigmentation (off-white, white or pale pink). To determine the rate and the amount of mycelium growth in malt extract agar at 28 °C, the diameter of the colony was measured every 24 h until the Petri dish was completely colonized. A linear model had the best fit to the mycelial growth kinetics. A direct relationship between mycelial morphology and growth rate was observed. Cottony mycelium presented significantly higher growth rates (p < 0.01) in comparison with floccose mycelium. Thus, mycelial morphology can be used as criterion to select which pairs must be used for optimizing compatible-mating studies. Hybrids resulting from cottony neohaplonts maintained the characteristically high growth rates of their parental strains with the hybrid R1-nxB1-n being faster than the latter. PMID:25477920
Two-Center Collaborative Evaluation of the Performance of the BD Phoenix Automated Microbiology System for Identification and Antimicrobial Susceptibility Testing of Enterococcus spp. and Staphylococcus spp.
Fahr, Anne-Marie; Eigner, Ulrich; Armbrust, Martina; Caganic, Alexandra; Dettori, Giuseppe; Chezzi, Carlo; Bertoncini, Luca; Benecchi, Magda; Menozzi, Maria Grazia
The performance of the BD Phoenix Automated Microbiology System (BD Diagnostic Systems, Sparks, Md.) was assessed for identification (ID) and antimicrobial susceptibility testing (AST) for the majority of clinically encountered bacterial isolates in a European collaborative two-center trial. A total of 469 bacterial isolates of the genera Staphylococcus (275 isolates), Enterococcus (179 isolates), and Streptococcus (15 isolates, for ID only) were investigated; of these, 367 were single patient isolates, and 102 were challenge strains tested at one center. Sixty-four antimicrobial drugs were tested, including the following drug classes: aminoglycosides, beta-lactam antibiotics, beta-lactam-beta-lactamase inhibitors, carbapenems, cephems, folate antagonists, quinolones, glycopeptides, macrolides-lincosamides-streptogramin B (MLS), and others. Phoenix ID results were compared to those of the laboratories' routine ID systems (API 32 Staph, API 32 Strep, and VITEK 2 [bioMérieux, Marcy l'Etoile, France]); Phoenix AST results were compared to those of frozen standard broth microdilution (SBM) panels according to NCCLS guidelines (NCCLS document M 100-S 9, approved standard M 7-A 4). Discrepant results were repeated in duplicate. Concordant IDs of 97.1, 98.9, and 100% were observed for staphylococci, enterococci, and streptococci, respectively. For AST results the overall essential agreement was 93.3%; the category agreement was 97.3%; and the very major error rate, major error rate, and minor error rate were 1.2, 1.9, and 1.3%, respectively. In conclusion, the Phoenix ID results showed high agreement with results of the systems to which they were being compared; the AST performance was highly equivalent to that of the SBM reference method. PMID:12624042
Kumari, Lata; Verma, Ajay Kumar; Tiwary, Dhanesh; Giri, Deen Dayal; Nath, Gopal; Mishra, Pradeep Kumar
Biodegradation of Navy N5RL1, a widely used acidic azo dye in carpet industry, was studied by bacterial strain isolated from the dye-contaminated soil collected from a carpet industry premises located in Bhadohi, Sant Ravidas Nagar and Uttar Pradesh, India. The isolated strain was identified as Staphylococcus saprophyticus BHUSS X3 on the basis of morphological, biochemical and 16S rRNA gene sequencing analysis. The strain BHUSS X3 decolorized 95.7 % of dye (100 mg/l) within 6 h at optimum pH 8, temperature 35 °C, inoculum 4.0 % under static condition during 24 h incubation. The isolated bacterial strain BHUSS X3 can toralate dye concentration upto 1,000 mg/l. The dye degradation metabolites were confirmed by analysis of degraded products using UV-Vis spectrophotometric, HPLC and FTIR technique. The phytotoxicity analysis was also conducted on Phaseolus aureus and enhanced seed germination was recorded.
Guntupalli, Rajesh; Sorokulova, Iryna; Olsen, Eric; Globa, Ludmila; Pustovyy, Oleg; Moore, Timothy; Chin, Bryan; Barbaree, James; Vodyanoy, Vitaly
Discrimination of methicillin resistant (MRSA) and sensitive (MSSA) strains of Staphylococcus aureus, was achieved by the specially selected lytic bacteriophage with a wide host range of S. aureus strains and a penicillin-binding protein (PBP 2a) specific antibody. A quartz crystal microbalance with dissipation monitoring (QCM-D) was employed to analyze bacteria-phage interactions. The lytic phages were transformed into phage spheroids by exposure to water-chloroform interface. Phage spheroid monolayers were transferred onto QCM-D sensors by Langmuir-Blodgett (LB) technique. Biosensors were tested in the flow mode with bacterial water suspensions, while collecting frequency and energy dissipation changes. Bacteria-spheroid interactions resulted in decreased resonance frequency and an increase in dissipation energy for both MRSA and MSSA strains. Following the bacterial binding, these sensors were further exposed to a flow of the penicillin-binding protein (PBP 2a) specific antibody conjugated latex beads. Sensors tested with MRSA responded to PBP 2a antibody beads; while sensors examined with MSSA gave no response. This experimental difference establishes an unambiguous discrimination between methicillin resistant and sensitive S. aureus strains. Both free and immobilized bacteriophages strongly inhibit bacterial growth on solid/air interfaces and in water suspensions. After lytic phages are transformed into spheroids, they retain their strong lytic activity and demonstrate high bacterial capture efficiency. The phage and phage spheroids can be used for screening and disinfection of antibiotic resistant bacteria. Other applications may include use on biosensors, bacteriophage therapy, and antimicrobial surfaces.
Betanzos-Cabrera, Gabriel; Montes-Rubio, Perla Y.; Fabela-Illescas, Héctor E.; Belefant-Miller, Helen; Cancino-Diaz, Juan C.
Background Polyphenols have received a great deal of attention due to their biological functions. Pomegranate (Punica granatum L.) is a polyphenol-rich fruit. In the past decade, studies testing the antimicrobial activity of pomegranates almost exclusively used solvent extracts instead of fresh pomegranate juice (FPJ). The use of FPJ instead of solvent extracts would reduce toxicity issues while increasing patient acceptance. We established a model to test FPJ as a natural antimicrobial agent. Objective To evaluate the antimicrobial activity of FPJ on clinical isolates of multidrug-resistant Staphylococcus epidermidis strains. Design Sixty strains of S. epidermidis isolated from ocular infections were grown in the presence of FPJ, and minimum inhibitory concentration (MIC) was determined by broth and agar dilution methods. Results FPJ at 20% had a MIC equal to 100% (MIC100%) on all 60 strains tested. This inhibition of FPJ was confirmed by the growth kinetics of a multidrug-resistant strain exposed to different concentrations of FPJ. Additionally, the antimicrobial activity of FPJ was compared against commercial beverages containing pomegranate: Ocean Spray® had a MIC100% at 20%, followed by Del Valle® with a MIC15% at 20% concentration only. The beverages Jumex® and Sonrisa® did not have any antimicrobial activity. FPJ had the highest polyphenol content and antioxidant capacity. Conclusions Overall, FPJ had antimicrobial activity, which might be attributed to its high polyphenol content and antioxidant capacity. PMID:25999265
Botka, Tibor; Růžičková, Vladislava; Konečná, Hana; Pantůček, Roman; Rychlík, Ivan; Zdráhal, Zbyněk; Petráš, Petr; Doškař, Jiří
Exfoliative toxin A (ETA)-coding temperate bacteriophages are leading contributors to the toxic phenotype of impetigo strains of Staphylococcus aureus. Two distinct eta gene-positive bacteriophages isolated from S. aureus strains which recently caused massive outbreaks of pemphigus neonatorum in Czech maternity hospitals were characterized. The phages, designated ϕB166 and ϕB236, were able to transfer the eta gene into a prophageless S. aureus strain which afterwards converted into an ETA producer. Complete phage genome sequences were determined, and a comparative analysis of five designed genomic regions revealed major variances between them. They differed in the genome size, number of open reading frames, genome architecture, and virion protein patterns. Their high mutual sequence similarity was detected only in the terminal regions of the genome. When compared with the so far described eta phage genomes, noticeable differences were found. Thus, both phages represent two new lineages of as yet not characterized bacteriophages of the Siphoviridae family having impact on pathogenicity of impetigo strains of S. aureus.
Iqbal, Zahid; Seleem, Mohamed N.; Hussain, Hafiz Iftikhar; Huang, Lingli; Hao, Haihong; Yuan, Zonghui
Several studies have been conducted to check the prevalence of methicillin-resistant strains of Staphylococcus aureus (MRSA) in animals and animal-derived food products but limited data are available regarding their virulence and associated gene expression profile. In the present study, antibiotic resistance and virulence of MRSA and methicillin-sensitive S. aureus animal isolates were determined in vitro by agar dilution, biofilm formation, adhesion, invasion and intracellular survivability assays. In addition, the pathogenicity of these isolates was examined in a murine model of S. aureus sepsis. MRSA1679a, a strain isolated from chicken, was observed to be highly virulent, in cell culture and in mouse model, and exhibited extensive resistant profile. Comparative gene expression profile of MRSA1679a and the reference human MRSA strain (ATCC 29213) was performed using Illumina-based transcriptome and RT-qPCR analyses. Several virulence elements including 22 toxin genes were detected in MRSA animal-isolate. In addition, we observed enhanced expression of crucial virulence regulators, such as sarA and KdpDE in MRSA animal-isolate compared to the human isolate. Collectively, gene expression profile including several virulence and drug-resistance factors confirmed the unique and highly virulent determinants of the MRSA strain of poultry origin which warrants further attention due to significant threat to public health. PMID:27739497
Bonar, Emilia; Wojcik, Iwona; Jankowska, Urszula; Kedracka-Krok, Sylwia; Bukowski, Michal; Polakowska, Klaudia; Lis, Marcin W.; Kosecka-Strojek, Maja; Sabat, Artur J.; Dubin, Grzegorz; Friedrich, Alexander W.; Miedzobrodzki, Jacek; Dubin, Adam; Wladyka, Benedykt
Staphylococcus aureus is a commensal inhabitant of skin and mucous membranes in nose vestibule but also an important opportunistic pathogen of humans and livestock. The extracellular proteome as a whole constitutes its major virulence determinant; however, the involvement of particular proteins is still relatively poorly understood. In this study, we compared the extracellular proteomes of poultry-derived S. aureus strains exhibiting a virulent (VIR) and non-virulent (NVIR) phenotype in a chicken embryo experimental infection model with the aim to identify proteomic signatures associated with the particular phenotypes. Despite significant heterogeneity within the analyzed proteomes, we identified alpha-haemolysin and bifunctional autolysin as indicators of virulence, whereas glutamylendopeptidase production was characteristic for non-virulent strains. Staphopain C (StpC) was identified in both the VIR and NVIR proteomes and the latter fact contradicted previous findings suggesting its involvement in virulence. By supplementing NVIR, StpC-negative strains with StpC, and comparing the virulence of parental and supplemented strains, we demonstrated that staphopain C alone does not affect staphylococcal virulence in a chicken embryo model. PMID:27242969
Rodriguez, Marcela; Hogan, Patrick G; Satola, Sarah W; Crispell, Emily; Wylie, Todd; Gao, Hongyu; Sodergren, Erica; Weinstock, George M; Burnham, Carey-Ann D; Fritz, Stephanie A
Historically, a number of typing methods have been evaluated for Staphylococcus aureus strain characterization. The emergence of contemporary strains of community-associated S. aureus, and the ensuing epidemic with a predominant strain type (USA300), necessitates re-evaluation of the discriminatory power of these typing methods for discerning molecular epidemiology and transmission dynamics, essential to investigations of hospital and community outbreaks. We compared the discriminatory index of 5 typing methods for contemporary S. aureus strain characterization. Children presenting to St. Louis Children's Hospital and community pediatric practices in St. Louis, Missouri (MO), with community-associated S. aureus infections were enrolled. Repetitive sequence-based PCR (repPCR), pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), staphylococcal protein A (spa), and staphylococcal cassette chromosome (SCC) mec typing were performed on 200 S. aureus isolates. The discriminatory index of each method was calculated using the standard formula for this metric, where a value of 1 is highly discriminatory and a value of 0 is not discriminatory. Overall, we identified 26 distinct strain types by repPCR, 17 strain types by PFGE, 30 strain types by MLST, 68 strain types by spa typing, and 5 strain types by SCCmec typing. RepPCR had the highest discriminatory index (D) of all methods (D = 0.88), followed by spa typing (D = 0.87), MLST (D = 0.84), PFGE (D = 0.76), and SCCmec typing (D = 0.60). The method with the highest D among MRSA isolates was repPCR (D = 0.64) followed by spa typing (D = 0.45) and MLST (D = 0.44). The method with the highest D among MSSA isolates was spa typing (D = 0.98), followed by MLST (D = 0.93), repPCR (D = 0.92), and PFGE (D = 0.89). Among isolates designated USA300 by PFGE, repPCR was most discriminatory, with 10 distinct strain types identified (D = 0.63). We identified 45
Rodriguez, Marcela; Hogan, Patrick G.; Satola, Sarah W.; Crispell, Emily; Wylie, Todd; Gao, Hongyu; Sodergren, Erica; Weinstock, George M.; Burnham, Carey-Ann D.; Fritz, Stephanie A.
Abstract Historically, a number of typing methods have been evaluated for Staphylococcus aureus strain characterization. The emergence of contemporary strains of community-associated S. aureus, and the ensuing epidemic with a predominant strain type (USA300), necessitates re-evaluation of the discriminatory power of these typing methods for discerning molecular epidemiology and transmission dynamics, essential to investigations of hospital and community outbreaks. We compared the discriminatory index of 5 typing methods for contemporary S. aureus strain characterization. Children presenting to St. Louis Children's Hospital and community pediatric practices in St. Louis, Missouri (MO), with community-associated S. aureus infections were enrolled. Repetitive sequence-based PCR (repPCR), pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), staphylococcal protein A (spa), and staphylococcal cassette chromosome (SCC) mec typing were performed on 200 S. aureus isolates. The discriminatory index of each method was calculated using the standard formula for this metric, where a value of 1 is highly discriminatory and a value of 0 is not discriminatory. Overall, we identified 26 distinct strain types by repPCR, 17 strain types by PFGE, 30 strain types by MLST, 68 strain types by spa typing, and 5 strain types by SCCmec typing. RepPCR had the highest discriminatory index (D) of all methods (D = 0.88), followed by spa typing (D = 0.87), MLST (D = 0.84), PFGE (D = 0.76), and SCCmec typing (D = 0.60). The method with the highest D among MRSA isolates was repPCR (D = 0.64) followed by spa typing (D = 0.45) and MLST (D = 0.44). The method with the highest D among MSSA isolates was spa typing (D = 0.98), followed by MLST (D = 0.93), repPCR (D = 0.92), and PFGE (D = 0.89). Among isolates designated USA300 by PFGE, repPCR was most discriminatory, with 10 distinct strain types identified (D = 0.63). We
Lu, Yong; Wang, Yiping; Ling, Buzhi; Ke, Xianfu; Ying, Jianfei; Yu, Yanhong; He, Mingyang; Li, Xiangyang
This report describes the results of the sequence analysis of a methicillin-susceptible strain of catalase-negative Staphylococcus lugdunensis. Molecular characterization of the deduced sequence revealed a novel point mutation in the catalase gene. To our knowledge, this is the first report of a catalase-negative S. lugdunensis strain, although catalase-negative isolates of Staphylococcus aureus and Staphylococcus epidermidis have been previously reported.
Zhao, Haoyu; Tao, Ke; Zhu, Jianyi; Liu, Shengnan; Gao, Han; Zhou, Xiaogang
Bacterial strains capable of utilizing glyphosate as the sole carbon source were isolated from contaminated soil by the enrichment culture method and identified based on partial 16S rRNA gene sequence analysis. Pseudomonas spp. strains GA07, GA09 and GC04 demonstrated the best degradation capabilities towards glyphosate and were used for the laboratory experiments of glyphosate bioremediation. Inoculating glyphosate-treated soil samples with these three strains resulted in a 2-3 times higher rate of glyphosate removal than that in non-inoculated soil. The degradation kinetics was found to follow a first-order model with regression values greater than 0.96. Cell numbers of the introduced bacteria decreased from 4.4 × 10(6) CFU/g to 3.4-6.7 × 10(5) CFU/g dry soil within 18 days of inoculation. Due to the intense degradation of glyphosate, the total dehydrogenase activity of the soil microbial community increased by 21.2-25.6%. Analysis of glyphosate degradation products in cell-free extracts showed that glyphosate breakdown in strain GA09 was catalyzed both by C-P lyase and glyphosate oxidoreductase. Strains GA07 and GC04 degraded glyphosate only via glyphosate oxidoreductase, but no further metabolite was detected. These results highlight the potential of the isolated bacteria to be used in the bioremediation of GP-contaminated soils.
Hamza, Muhammad; Nadir, Maha; Mehmood, Nadir; Farooq, Adeel
Objectives: The aim of this study is to evaluate the effect of four triterpenoids such as oleanolic acid, ursolic acid, cycloastragenol, and beta-boswellic acid alone and in combination with antibiotics against Staphylococcus aureus strains. Materials and Methods: Sixteen clinical strains of S. aureus from infected wounds were isolated. Eight were methicillin-sensitive S. aureus (MSSA), and the other eight were methicillin-resistant S. aureus (MRSA). The activity was also seen in reference S. aureus American Type Culture Collection™ strains. The activity of all the triterpenoids and antibiotics against S. aureus was evaluated by broth microdilution method. The effectiveness was judged by comparing the minimum inhibitory concentrations (MICs) of the compounds with antibiotics. The combination of antibiotics with compounds was evaluated by their fractional inhibitory concentrations (FIC). Results: Against both clinical and reference MSSA strains, none of the compounds exhibited comparable activity to antibiotics vancomycin or cefradine except for ursolic acid (MIC 7.8 μg/ml). Against MRSA, all compounds (MIC 16–128 μg/ml) showed lesser activity than vancomycin (MIC 5.8 μg/ml). Among triterpenoid-antibiotic combinations, the most effective were ursolic acid and vancomycin against clinical strain MSSA (FICS 0.17). However, overall, different combinations between triterpenoids and antibiotics showed 95%–46% (P < 0.05) reduction in MICs of antibiotics compared to when antibiotics were used alone. Cefradine, a drug not suitable for treating MRSA (MIC = 45 μg/ml), showed a remarkable decrease in its MIC (87% P< 0.01) when it was used in combination with oleanolic acid or ursolic acid in both clinical and reference strains. Conclusion: The tested triterpenoids are relatively weaker than antibiotics. However, when used in combination with antibiotics, they showed remarkable synergistic effect and thus can help in prolonging the viability of these antibiotics
Udomsil, Natteewan; Rodtong, Sureelak; Tanasupawat, Somboon; Yongsawatdigul, Jirawat
Staphylococcus sp. CMC5-3-1 and CMS5-7-5 isolated from fermented fish sauce at 3 to 7 mo, respectively, showed different characteristics on protein hydrolysis and volatile formation. These Gram-positive cocci were able to grow in up to 15% NaCl with the optimum at 0.5% to 5% NaCl in tryptic soy broth. Based on ribosomal 16S rRNA gene sequences, Staphylococcus sp. CMC5-3-1 and CMS5-7-5 showed 99.0% similarity to that of Staphylococcus piscifermentans JCM 6057(T) , but DNA-DNA relatedness was <30%, indicating that they were likely to be new species. DNA relatedness between these 2 strains was only 65%, suggesting that they also belonged to different species. The α-amino group content of 6-month-old fish sauce inoculated with Staphylococcus sp. CMC5-3-1 was 740.5 mM, which was higher than that inoculated by the strain CMS5-7-5 (662.14 mM, P < 0.05). Histamine was not produced during fermentations with both strains. Fish sauce inoculated with Staphylococcus sp. CMC5-3-1 showed the highest content of total glutamic acid (P < 0.05). The major volatile compound detected in fish sauce inoculated with Staphylococcus sp. CMC5-3-1 was 2-methypropanal, contributing to the desirable dark chocolate note. Staphylococcus sp. CMC5-3-1 could be applied as a starter culture to improve the umami and aroma of fish sauce.
Matyi, S A; Dupre, J M; Johnson, W L; Hoyt, P R; White, D G; Brody, T; Odenwald, W F; Gustafson, J E
The primary purpose of this study was to determine if methicillin-resistant Staphylococcus aureus (MRSA) strains could be identified in the milk of dairy cattle in a Paso del Norte region dairy of the United States. Using physiological and PCR-based identification schemes, a total of 40 Staph. aureus strains were isolated from 29 raw milk samples of 133 total samples analyzed. Pulsed-field gel electrophoresis after digestion with the SmaI enzyme revealed that the 40 confirmed strains were represented by 5 pulsed-field types, which each contained 3 or more strains. Of 7 hospital strains isolated from cows undergoing antibiotic therapy, 3 demonstrated resistance to 3 or more antimicrobial classes and displayed similar pulsed-field gel electrophoresis patterns. A secondary purpose of this study was to elucidate the evolutionary relationships of strains isolated in this study to genomically characterized Staph. aureus strains. Therefore, Roche 454 GS (Roche Diagnostics Corp., Dallas, TX) pyrosequencing was used to produce draft genome sequences of an MRSA raw milk isolate (H29) and a methicillin-susceptible Staph. aureus (PB32). Analysis using the BLASTn database (http://blast.ncbi.nlm.nih.gov/) demonstrated that the H29 draft genome was highly homologous to the human MRSA strain JH1, yet the β-lactamase plasmid carried by H29 was different from that carried by JH1. Genomic analysis of H29 also clearly explained the multidrug resistance phenotype of this raw milk isolate. Analysis of the PB32 draft genome (using BLASTn) demonstrated that this raw milk isolate was most related to human MRSA strain 04-02981. Although PB32 is not a MRSA, the PB32 draft genome did reveal the presence of a unique staphylococcal cassette mec (SCCmec) remnant. In addition, the PB32 draft genome revealed the presence of a novel bovine staphylococcal pathogenicity island, SaPIbovPB32. This study demonstrates the presence of clones closely related to human and (or) bovine Staph. aureus strains
Rozwadowska, Beata; Albertyńska, Marta; Hudzik, Grzegorz; Okła, Hubert; Jasik, Krzysztof P; Słodki, Jan
The diagnostic assessment of water sanitary state is based mainly on the cultivation of bacteria retained on membrane filters. However classical microbiology methods have a lot of disadvantages. More and more frequently, rapid detection and identification of pathogens present in water is based on molecular biology techniques. The aim of this study was to determine the effectiveness and usefulness of a real-time PCR method, when compared to the recommended bacteria culture method, in diagnostics of pathogens in water samples. The research concerned the detection and identification of main sanitary indicators of water such as: Salmonella spp., Escherichia coli, Staphylococcus aureus and Clostridium perfringens. The analyses were conducted in water samples contaminated with the reference material (the aforementioned bacteria) and real environmental samples, which were examined for the presence of nucleic acid of: Salmonella spp., E. coli, S. aureus and C. perfringens using a real-time PCR method.
Córdova-Guerrero, Jesús; Hernández-Guevara, Esteban; Ramírez-Zatarain, Sandy; Núñez-Bautista, Marco; Ochoa-Terán, Adrián; Muñiz-Salazar, Raquel; Montes-Ávila, Julio; López-Angulo, Gabriela; Paniagua-Michel, Armando; Nuño Torres, Gustavo A.
Staphylococcus aureus is one of the most common causes of nosocomial infections. The purpose of this study was the synthesis and in vitro evaluation of antimicrobial activity of 10 new 3-oxazolidin-2-one analogues on 12 methicillin resistant S. aureus (MRSA) clinical isolates. S. aureus confirmation was achieved via catalase and coagulase test. Molecular characterization of MRSA was performed by amplification of the mecA gene. Antimicrobial susceptibility was evaluated via the Kirby-Bauer disc diffusion susceptibility test protocol, using commonly applied antibiotics and the oxazolidinone analogues. Only (R)-5-((S)-1-dibenzylaminoethyl)-1,3-oxazolidin-2-one (7a) exhibited antibacterial activity at 6.6 μg. These results, allow us to infer that molecules such as 7a can be potentially used to treat infections caused by MRSA strains. PMID:24675696
Hauschild, T; Schwarz, S
Twenty-nine Staphylococcus sciuri strains isolated from free-living insectivores and rodents were comparatively analysed for their biochemical capacities and their SmaI macrorestriction patterns. The 29 S. sciuri isolates represented 21 different biotypes and 22 different SmaI macrorestriction types. This observation confirmed that S. sciuri isolates obtained from insectivores and rodents living in natural environments constituted a heterogeneous population. Cluster analysis revealed that the macrorestriction patterns and the biochemical profiles matched in some cases. However, S. sciuri isolates that exhibited the same or closely related biochemical profiles were also found to be associated with different macrorestriction patterns. Analysis of the 29 S. sciuri isolates for their plasmid content and their sensitivity to antimicrobial agents showed that most of the isolates were plasmid-free and susceptible to all antimicrobial agents tested.
Vindel, A.; Trincado, P.; Gomez, E.; Aparicio, P.; Martin de Nicolas, M.; Boquete, T.; Saez Nieto, J. A.
In recent years, methicillin-resistant Staphylococcus aureus (MRSA) isolates in Spain have increased dramatically; in 1986 there were only 1.2% MRSA amongst all nosocomial Staphylococcus aureus (SA) isolates, by 1989 this percentage had risen to 44% in some hospital causing a very serious epidemic situation in the country. We have characterized these isolates by direct, reverse and Fisk phage typing and we have also looked for an additional local set of phages to help us to differentiate these strains. We have been able to differentiate an epidemic strain from other MRSA strains which cause sporadic hospital outbreaks, and we have also distinguished between some variants of the epidemic strain. PMID:8150004
Brown, Vienna R; Adney, Danielle R; Bielefeldt-Ohmann, Helle; Gordy, Paul W; Felix, Todd A; Olea-Popelka, Francisco J; Bowen, Richard A
Francisella tularensis is a highly virulent, zoonotic bacterium that causes significant natural disease and is of concern as an organism for bioterrorism. Serologic testing of wildlife is frequently used to monitor spatial patterns of infection and to quantify exposure. Cottontail rabbits (Sylvilagus spp.) are a natural reservoir for F. tularensis in the US, although very little work has been done experimentally to determine how these animals respond to infection; thus, information gathered from field samples can be difficult to interpret. We characterized clinical disease, bacteremia, pathology, and antibody kinetics of North American cottontail rabbits experimentally infected with five strains of F. tularensis. Rabbits were infected with four field strains, including MA00-2987 (type A1b), WY96-3418 (type A2), KY99-3387, and OR96-0246 (type B), and with SchuS4 (type A1a), a widely used, virulent laboratory strain. Infection with the different strains of the bacterium resulted in varied patterns of clinical disease, gross pathology, and histopathology. Each of the type A strains were highly virulent, with rabbits succumbing to infection 3-13 d after infection. At necropsy, numerous microabscesses were observed in the livers and spleens of most rabbits, associated with high bacterial organ burdens. In contrast, most rabbits infected with type B strains developed mild fever and became lethargic, but the disease was infrequently lethal. Those rabbits infected with type B strains that survived past 14 d developed a robust humoral immune response, and F. tularensis was not isolated from liver, spleen, or lung of those animals. Understanding F. tularensis infection in a natural reservoir species can guide serosurveillance and generate new insights into environmental maintenance of this pathogen.
Sudağidan, Mert; Cavuşoğlu, Cengiz; Bacakoğlu, Feza
Staphylococci are the most important agents of nosocomial infections originating from biomaterials. The aim of this study was to investigate the presence of virulence genes and their phenotypic expressions in 11 methicillin-resistant Staphylococcus aureus strains isolated from the surfaces of clinically used biomaterials of 48 thorasic intensive-care unit patients. By the use of specific primers, the presence of genes encoding the attachment and biofilm production (icaA, icaC, bap), methicillin resistance (mecA), enterotoxins A-E (sea, seb, sec, sed, see), toxic shock syndrome toxin (tst), exfoliative toxins A and B (eta and etb), alpha- and beta-hemolysins (hla and hlb), staphylococcal exotoxin-like protein-1 (set1), proteases (sspA, sspB, aur, serine proteaz gene), lipase (geh) and the regulatory genes (sarA and agrCA) were investigated by polymerase chain reaction (PCR). The phenotypic properties of the isolates such as biofilm formation, antibiotic susceptibility, extracellular protease and lipase production were also evaluated. None of the isolates were found to be biofilm and/or slime producers, however, all strains were found to have icaA gene which is responsible for biofilm formation. Nevertheless the presence of icaC and bap genes that are also responsible for biofilm formation were not detected. All the strains have had mecA gene and were resistant to oxacillin, penicilin G and gentamicin, while 10 were also resistant to erythromycin and nine were also resistant to ofloxacin. The isolates were susceptible to vancomycin, teicoplanin and co-trimoxazole. Screening of toxin and regulatory genes revealed that all the strains harboured sea, set1, hla, hlb and sarA genes. The phenotypic tests for the determination of extracellular protease production revealed that all the strains formed very weak zones on skim milk and milk agar plates, and yielded negative results on casein agar plates. Furthermore, all strains were found to harbour sspA, sspB, aur and serine
Javid Khojasteh, Vahideh; Alfakhri, Souad; Foster, Howard Anthony
Previous studies had shown that sub-inhibitory concentrations of silver sulphadiazine (AgSD) stimulated the production of Toxic Shock Syndrome Toxin-1 in certain strains (responder strains) of Staphylococcus aureus and that protease production was also affected. No changes were detected in other strains (non-responders). Extracellular proteins from eleven responder and non-responder strains grown with and without AgSD were separated by SDS PAGE. There were three classes of response, responder strains that showed enhancement of synthesis of certain proteins, non-responder strains that showed no change and responder strains that showed a general decrease in exoprotein production in the early stages of growth. The results showed that the effects of AgSD were complex and that S. aureus strains were heterogenous with respect to their response to sub-inhibitory concentrations of AgSD.
Peyrani, P; Allen, M; Seligson, D; Roberts, C; Chen, A; Haque, N; Zervos, M; Wiemken, T; Harting, J; Christensen, D; Ramirez, R
Methicillin-resistant Staphylococcus aureus (MRSA) USA-300 strains have emerged as an important cause of community-acquired infections. These strains have been recognized as an etiology of osteomyelitis but data on their incidence and outcomes are limited. We retrospectively studied the incidence and clinical outcomes of MRSA USA-300 osteomyelitis in patients at the University of Louisville Hospital and the Henry Ford Health System between January 2007 and March 2008. Pulsed-field gel electrophoresis was used to determine USA type. Clinical outcomes were defined as management success versus failure at 12 months. Chi-square tests, Fisher exact tests, and Mann-Whitney tests were used to compare patient characteristics on the basis of clinical outcomes and USA type. Of the 50 patients with MRSA osteomyelitis, 27 (54%) had the USA-300 strain. Clinical failure was identified in 22% (6/27) of the patients with MRSA USA-300 and in 30% (7/23) of the patients with MRSA non-USA-300 osteomyelitis (P = .509). Our results showed that MRSA USA-300 is a significant etiology of MRSA osteomyelitis. With current surgical and medical management, outcomes of patients with MRSA USA-300 osteomyelitis are similar to those of patients with MRSA non-USA-300 osteomyelitis.
Méndez-Vilas, A.; Gallardo-Moreno, A. M.; González-Martín, M. L.; Calzado-Montero, R.; Nuevo, M. J.; Bruque, J. M.; Pérez-Giraldo, C.
Slime-producer Staphylococcus epidermidis is one opportunistic bacteria directly related to biomaterial infections inside the human body. The characterisation of the bacterial surface is crucial when trying to control its adhesion process and prevent the biofilm formation. This work aims to analyse the microscopic and submicroscopic surface structure of two strains of S. epidermidis with different slime production, as well as mapping the surface interaction forces. Atomic force microscopy (AFM) shows that S. epidermidis ATCC35984 is covered by a granular-like film, highly compacted with the presence of repeated "holes". However, S. epidermidis ATCC35983 only shows a partial coverage by a less compacted granular-like film, mainly located in the inter-cellular zones. Both films are related to the slime of the two strains studied. As regards to the adhesion forces, results show a greater adhesion of the tip to the slime covering S. epidermidis ATCC35984, than that covering the surface of S. epidermidis ATCC35983. In addition, the adhesion to the free-slime zones of the last strain was higher than to the slime-covered parts.
Ouyang, Ping; Chen, Junjie; Sun, Mao; Yin, Zhongqiong; Lin, Juchun; Fu, Hualin; Shu, Gang; He, Changliang; Lv, Cheng; Deng, Xuming; Wang, Kaiyu; Geng, Yi; Yin, Lizi
Both community-associated and hospital-acquired infections with methicillin-resistant Staphylococcus aureus (MRSA) have been increasingly reported around the world in the past 20 years. In 2006, the Centers for Disease Control and Prevention reported that 64 % of MRSA isolates were of the USA300 clonal type in infected patients in USA. The aim of our study was to estimate the in vitro effect of imperatorin on MRSA strain BAA-1717 (USA300). The effects of imperatorin on alpha-hemolysin (Hla) production, when strain BAA-1717 was co-cultured with sub-inhibitory concentrations of imperatorin, were analysed using susceptibility testing, hemolysis assays, western blotting and real-time PCR. Live/Dead analysis and cytotoxicity assays were employed to examine the protective effect of imperatorin against the strain BAA-1717-mediated injury of human alveolar epithelial cells (A549). The results showed that imperatorin has no anti-S. aureus activity at the tested concentrations in vitro. However, imperatorin can observably inhibit the production of Hla in culture supernatants and reduce the transcriptional levels of hla (the gene encoding Hla) and arg (the accessory gene regulator). Imperatorin prevented Hla-mediated A549 epithelial cell injury in a co-culture system. In conclusion, our results suggested that imperatorin has the potential to be developed as a new anti-virulence drug candidate for managing S. aureus infection.
Messad, Nourreddine; Prajsnar, Tomasz K.; Lina, Gerard; O’Callaghan, David; Foster, Simon J.; Renshaw, Steve A.; Skaar, Eric P.; Bes, Michèle; Dunyach-Remy, Catherine; Vandenesch, François; Sotto, Albert
Staphylococcus aureus is an opportunistic bacterium capable of causing a wide range of severe diseases when it gains access to underlying tissues. Paradoxically, S. aureus is a common inhabitant of the skin microflora and colonizes the nares and other human mucosa. The purpose of this study was to determine the genetic basis for the differences in the pathogenic versus colonizing potential of S. aureus isolated from diabetic foot ulcers (DFUs). By performing optical map comparisons of a collection of S. aureus strains isolated from DFUs, we brought to light a prophage present in noninfecting bacteria. The phage, namely ROSA-like, was localized in a hotspot region ΦNM2 near the locus isd, the iron surface determinant system. The integrated phage significantly reduces the virulence of the strain and increases the biofilm formation. DFUs seem to be a specific niche of this colonizing strain. The ROSA-like phage represents the first description of a mobile element present mainly in S. aureus isolated from DFUs, which modulates the relationship of the bacteria with its human host. This phage appears to attenuate bacterial virulence and promote colonization. PMID:25901094
Hait, Jennifer M; Tallent, Sandra M; Bennett, Reginald W
Staphylococcus aureus continues to play a significant role in foodborne outbreak investigations, with numerous individuals sickened each year after ingesting assorted foods contaminated with staphylococcal enterotoxins. The purpose of this study was to evaluate the use of several methods for the screening, detection, and enterotoxin serotyping of staphylococcal bacterial strains for classical staphylococcal enterotoxins (SEs; SEA, SEB, SEC, SED, and SEE) and the newly described SE and SE-like enterotoxin genes (seg, seh, sei, sej, sek, sel, sem, sen, seo, sep, seq, ser, ses, set, and seu). Inclusivity and exclusivity panels of staphylococcal strains were tested using a multiplex PCR method in addition to three polyvalent commercially prepared ELISA systems for the detection of SEA-SEE and one monovalent assay for the identification of classical SE serotypes. The results indicate an overall agreement between serological detection methods with a few exceptions, and molecular characterization identified an abundance of SE and SE-like enterotoxin genes including several potentially enterotoxigenic isolates that would have otherwise been missed by ELISA-based methods. These findings demonstrate the significance of PCR for future screening purposes and the use of ELISA systems for the detection and enterotoxin serotyping of staphylococcal bacterial strains.
Cotar, Ani-Ioana; Chifiriuc, Mariana-Carmen; Dinu, Sorin; Bucur, Marcela; Iordache, Carmen; Banu, Otilia; Dracea, Olguta; Larion, Cristina; Lazar, Veronica
Staphylococcus (S.) aureus and Pseudomonas (Ps.) aeruginosa are two of the most frequently opportunistic pathogens isolated in nosocomial infections, responsible for severe infections in immunocompromised hosts. The frequent emergence of antibiotic-resistant S. aureus and Ps. aeruginosa strains has determined the development of new strategies in order to elucidate the different mechanisms used by these bacteria at different stages of the infectious process, providing the scientists with new procedures for preventing, or at least improving, the control of S. aureus and Ps. aeruginosa infections. The purpose of this study was to characterize the molecular markers of virulence in S. aureus and Ps. aeruginosa strains isolated from different clinical specimens. We used multiplex and uniplex PCR assays to detect the genes encoding different cell-wall associated and extracellular virulence factors, in order to evaluate potential associations between the presence of putative virulence genes and the outcome of infections caused by these bacteria. Our results demonstrate that all the studied S. aureus and Ps. aeruginosa strains synthesize the majority of the investigated virulence determinants, probably responsible for different types of infections. PMID:21614207
Cascioferro, Stella; Maggio, Benedetta; Raffa, Demetrio; Raimondi, Maria Valeria; Cusimano, Maria Grazia; Schillaci, Domenico; Manachini, Barbara; Plescia, Fabiana; Daidone, Giuseppe
The ability of several N-phenyl-1H-pyrazole-4-carboxamide derivatives and other pyrazoles opportunely modified at the positions 3, 4 and 5, to reduce the formation of the biofilm in some Staphylococcus aureus strains (ATCC 29213, ATCC 25923 and ATCC 6538) were investigated. All the tested compounds were able, although to a different extent, to reduce the biofilm formation of the three bacterial strains considered. Among these, the 1-(2,5-dichlorophenyl)-5-methyl-N-phenyl-1H-pyrazole-4-carboxamide 14 resulted as the best inhibitor of biofilm formation showing an IC50 ranging from 2.3 to 32 μM, against all the three strains of S. aureus. Compound 14 also shows a good protective effect in vivo by improving the survival of wax moth larva (Galleria mellonella) infected with S. aureus ATCC 29213. These findings indicate that 14d is a potential lead compound for the development of new anti-virulence agents against S. aureus infections.
Johler, Sophia; Stephan, Roger; Althaus, Denise; Ehling-Schulz, Monika; Grunert, Tom
Staphylococcus aureus causes a variety of serious illnesses in humans and animals. Subtyping of S. aureus isolates plays a crucial role in epidemiological investigations. Metabolic fingerprinting by Fourier-transform infrared (FTIR) spectroscopy is commonly used to identify microbes at species as well as subspecies level. In this study, we aimed to assess the suitability of FTIR spectroscopy as a tool for S. aureus subtyping. To this end, we compared the subtyping performance of FTIR spectroscopy to other subtyping methods such as pulsed field gel electrophoresis (PFGE) and spa typing in a blinded experimental setup and investigated the ability of FTIR spectroscopy for identifying S. aureus clonal complexes (CC). A total of 70 S. aureus strains from human, animal, and food sources were selected, for which clonal complexes and a unique virulence and resistance gene pattern had been determined by DNA microarray analysis. FTIR spectral analysis resulted in high discriminatory power similar as obtained by spa typing and PFGE. High directional concordance was found between FTIR spectroscopy based subtypes and capsular polysaccharide expression detected by FTIR spectroscopy and the cap specific locus, reflecting strain specific expression of capsular polysaccharides and/or other surface glycopolymers, such as wall teichoic acid, peptidoglycane, and lipoteichoic acid. Supervised chemometrics showed only limited possibilities for differentiation of S. aureus CC by FTIR spectroscopy with the exception of CC45 and CC705. In conclusion, FTIR spectroscopy represents a valuable tool for S. aureus subtyping, which complements current molecular and proteomic strain typing.
van der Borden, A J; van der Mei, H C; Busscher, H J
Infection of percutaneous biomaterials implants, such as fixation frames used for the repair of complicated fractures in orthopedics, is a major complication that almost inevitably leads to replacement of the implant. As antibiotic therapy usually has little impact on biomaterial-associated infections, it is the aim of this article to examine whether implant-associated Staphylococcus epidermidis and Staphylococcus aureus strains could be stimulated to detach from a surgical stainless steel anode during application of an electric current. First, bacteria were allowed to adhere from a flowing suspension of physiological ionic strength in a parallel plate flow chamber to a stainless-steel surface, after which the suspension was replaced by a bacterium-free solution with a specified ionic strength (0.5-150-mM potassium phosphate). DC currents ranging from 15 to 125 microA were applied to induce bacterial detachment. Initial detachment decreased with increasing ionic strength at 100 microA. The percentage detachment achieved by application of an electric current after 2.5 h was highest (95%) in 1-mM potassium phosphate and decreased to 15% when the ionic strength exceeded 40 mM. The electric current did not significantly affect the percentage detachment, but initial detachment rates increased with increasing current from 1000 cm(-2) s(-1) at 15 microA to 7000 cm(-2) s(-1) at 125 microA. Although different isolates of S. epidermidis and S. aureus showed different patterns of current-induced detachment, all strains could be stimulated to detach. The results of this study define ionic-strength conditions and electric currents yielding staphylococcal detachment from surgical stainless steel and therewith point to a pathway for the treatment and prevention of percutaneous metal-implant infection.
Governa, Paolo; Miraldi, Elisabetta; De Fina, Gianna; Biagi, Marco
Bacterial resistance is an ongoing challenge for pharmacotherapy and pharmaceutical chemistry. Staphylococcus aureus is the bacterial species which makes it most difficult to treat skin and soft tissue infections and it is seen in thousands of hospitalization cases each year. Severe but often underrated infectious diseases, such as complicated nasal infections, are primarily caused by MRSA and S. epidermidis too. With the aim of studying new drugs with antimicrobial activity and effectiveness on drug resistant Staphylococcus strains, our attention in this study was drawn on the activity of a new association between two natural products: 5-pyrrolidone-2-carboxylic acid (PCA), naturally produced by certain Lactobacillus species, and copper sulfate pentahydrate (CS). The antimicrobial susceptibility test was conducted taking into account 12 different Staphylococcus strains, comprising 6 clinical isolates and 6 resistant strains. PCA 4%, w/w, and CS 0.002%, w/w, association in distilled water solution was found to have bactericidal activity against all tested strains. Antimicrobial kinetics highlighted that PCA 4%, w/w, and CS 0.002% association could reduce by 5 log10 viable bacterial counts of MRSA and oxacillin resistant S. epidennidis in less than 5 and 3 minutes respectively. Microscopic investigations suggest a cell wall targeting mechanism of action. Being very safe and highly tolerated, the natural product PCA and CS association proved to be a promising antimicrobial agent to treat Staphylococcus related infections.
Laohavaleeson, Somvadee; Tessier, Pamela R; Nicolau, David P
Ceftobiprole (BPR) is an investigational cephalosporin with activity against Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA) strains. The pharmacodynamic (PD) profile of BPR against S. aureus strains with a variety of susceptibility phenotypes in an immunocompromised murine pneumonia model was characterized. The BPR MICs of the test isolates ranged from 0.25 to 2 mug/ml. Pharmacokinetic (PK) studies were conducted with infected neutropenic BALB/c mice; and the BPR concentrations were measured in plasma, epithelial lining fluid (ELF), and lung tissue. PD studies with these mice were undertaken with eight S. aureus isolates (two methicillin-susceptible S. aureus strains, three hospital-acquired MRSA strains, and three community-acquired MRSA strains). Subcutaneous BPR doses of 2 to 125 mg/kg of body weight/day were administered, and the change in the number of log(10) CFU/ml in lungs was evaluated after 24 h of therapy. The PD profile was characterized by using the free drug exposures (f) determined from the following parameters: the percentage of time that the concentration was greater than the MIC (T > MIC), the maximum concentration in serum/MIC, and the area under the concentration-time curve/MIC. The BPR PK parameters were linear over the dose range studied in plasma, and the ELF concentrations ranged from 60 to 94% of the free plasma concentration. fT > MIC was the parameter that best correlated with efficacy against a diverse array of S. aureus isolates in this murine pneumonia model. The 80% effective dose (ED(80)), ED(50), and stasis exposures appeared to be similar among the isolates studied. BPR exerted maximal antibacterial effects when fT > MIC ranged from 6 to 22%, regardless of the phenotypic profile of resistance to beta-lactam, fluoroquinolone, erythromycin, clindamycin, or tetracycline antibiotics.
Mastouri, M; Nour, M; Ben Nejma, M; Bouallegue, O; Hammami, M; Khedher, M
The adaptation of Staphylococcus aureus to the hospital environment led to the acquisition of resistance to all antibiotics available in clinical practice. The aim of this study was to investigate the methicillin-resistant Staphylococcus aureus (MRSA) strains isolated in the F. Bourguiba hospital of Monastir (Tunisia). We determined the antibiotype of all Staphylococcus aureus strains identified. Susceptibility rates to fosfomycin, chloramphenicol, rifampicin and pristinamycin were 7%, 3%, 2% and 0%, respectively. The prevalence of MRSA was 15.5% (96 strains); their susceptible to gentamicin progressively increased. The minimum inhibitory concentration (MICs) of oxacillin, vancomycin and teicoplanin were evaluated for the 96 MRSA strains. We identified two MRSA strains (M4 and M41) showing reduced glycopeptides susceptibility. Further analysis revealed that M4 and M41 harbor the gene encoding the class S and class F proteins specific for the Panton-Valentine Leukocidin (PVL). The mecA gene was detected only in strain M41 which harbors the Staphylococcal Cassette Chromosome (SCCmec) type III. This is the first reported MRSA showing reduced susceptibility to glycopeptides in Tunisia. Regulatory surveillance of susceptibility to antibiotics is needed to reduce the morbidity and the mortality rates as well as societal costs of S. aureus infections.
Schubert, Justyna; Podkowik, Magdalena; Bystroń, Jarosław; Bania, Jacek
Twenty Staphylococcus aureus strains harboring seh gene, including one carrying also sec gene and 11 sea gene, were grown in BHI+YE broth and milk and were tested for SEA, SEC and SEH production. All strains decreased pH of BHI+YE broth at 24h and increased them at 48h. Seventeen S. aureus strains grown in milk changed pH for no >0.3 unit until 48h. Three other S. aureus strains significantly decreased pH during growth in milk. All S. aureus produced SEH in BHI+YE broth in amounts ranging from 95 to 1292ng/ml, and from 170 to 4158ng/ml at 24 and 48h, respectively. SEH production in milk by 17 strains did not exceed 23ng/ml at 24h and 36ng/ml at 48h. Three S. aureus strains able to decrease milk pH produced 107-3029ng/ml and 320-4246ng/ml of SEH in milk at 24 and 48h, respectively. These strains were grown in milk and BHI+YE broth with pH stabilized at values near neutral leading to a significant decrease of SEH production. Representative weak SEH producers were grown in milk at reduced pH resulting in moderate increase in SEH production. SEA was produced in milk by 10S. aureus strains at 24-151ng/ml at 24h, and 31-303ng/ml at 48h. SEA production in milk was higher or comparable as in BHI+YE broth in 3 strains and lower for remaining strains. Production of SEC by sec-positive S. aureus strains was lower in milk than in BHI+YE broth, ranging from 131 to 2319ng/ml at 24 and 48h in milk and 296-30,087ng/ml in BHI+YE at 24 and 48h. Both lacE and lacG transcripts involved in lactose metabolism were significantly up-regulated in milk in strong SEH producers. In these strains hld, rot and sarA transcripts were up-regulated in milk as compared to weak SEH producers. Stabilization of milk pH at a value of raw milk significantly down-regulated hld, rot and sarA RNA in strong SEH producers. Milk was generally found unfavorable for enterotoxin production. However, certain S. aureus strains were not restricted in SEH and SEA expression in milk, unlike SEC which remained down
Fraqueza, M J; Martins, A; Borges, A C; Fernandes, M H; Fernandes, M J; Vaz, Y; Bessa, R J B; Barreto, A S
The aim of the current work was to evaluate the prevalence and antimicrobial susceptibility of Campylobacter spp. isolated from different chicken production systems at the slaughterhouse level. Chicken sampling at slaughterhouse was performed for cecum, carcass, and breast meat from flocks of organic (n = 6), extensive indoor (n = 14), and intensive production (n = 14), totaling 34 ceca pools, 64 neck skin pools, and 132 breasts, representing 96,386 chickens. A collection of 167 strains were identified as Campylobacter coli (n = 85) and Campylobacter jejuni (n = 82) and were tested for susceptibility to 11 antimicrobial agents by the disk diffusion method. The frequency of Campylobacter in chicken samples from different production systems was between 79 and 100%. Campylobacter isolated from all origins were resistant to the fluoroquinolones studied (80-98%). However, for ciprofloxacin and ofloxacin, the Campylobacter isolates from extensive indoor chicken were significantly (P < 0.05) less resistant (77 and 58%) than that from organic (97 and 91%) and intensive production (96 and 95%). A high probability of tetracycline resistance occurrence was also found for the Campylobacter spp. tested (58% for C. jejuni and 76% for C. coli). A more frequent profile of multidrug resistance was noticed for isolates from intensive and organic production than for extensive indoor production. These results reinforce the need of efficient strategy implementation to control and reduce Campylobacter in chickens at production and slaughter levels, and the necessity to reduce the use of antimicrobials in poultry sector.
Traversa, A; Gariano, G R; Gallina, S; Bianchi, D M; Orusa, R; Domenis, L; Cavallerio, P; Fossati, L; Serra, R; Decastelli, L
Following the detection of methicillin-resistant Staphylococcus aureus (MRSA) ST398 in food-producing animals, both livestock and wildlife, and derived products, are considered potential sources of MRSA in humans. There is a paucity of data on MRSA in foods in Italy, and the data regarding wild animals are particularly scarce. A total of 2162 food samples collected during official monitoring activities in 2008 were analyzed for the detection of S. aureus. Also, samples from 1365 wild animals collected by the National Reference Center for Wild Animal Diseases in 2003-2009 were subjected to anatomopathological examination. S. aureus isolates were processed for phenotypic and molecular methicillin resistance determinations. S. aureus was found in 2.0% of wild animal carcasses and in 3.2% of wild boar lymph nodes: none showed methicillin resistance. The prevalence of S. aureus in food was 17.1%. Two MRSA strains, both from bulk tank milk (prevalence 0.77%) were isolated: the strains were resistant to tetracycline, had spa-type t899, and were negative for the Panton-Valentine leukocidin gene. The low prevalence of MRSA suggests that the risk of transmission to humans via food is limited. However, attention should be paid to the cattle food chain, which may be a potential route of transmission of LA-MRSA.
Pamplona-Zomenhan, Lucila Coelho; Pamplona, Beatriz Coelho; da Silva, Cely Barreto; Marcucci, Maria Cristina; Mimica, Lycia Mara Jenné
Staphylococcus aureus (S. aureus) is one of the most frequent causes of hospital acquired infections. With the increase in multiple drug resistant strains, natural products such as propolis are a stratagem for new product discovery. The aims of this study were: to determine the in vitro antimicrobial activity of an ethanol extract of propolis; to define the MIC50 and MIC90 (Minimal Inhibitory Concentration – MIC) against 210 strains of S. aureus; to characterize a crude sample of propolis and the respective ethanol extract as to the presence of predetermined chemical markers. The agar dilution method was used to define the MIC and the high performance liquid chromatography (HPLC) method was used to characterize the samples of propolis. MIC results ranged from 710 to 2,850 µg/mL. The MIC50 and MIC90 for the 210 strains as well as the individual analysis of American Type Culture Collection (ATCC) strains of Methicillin-susceptible Staphylococcus aureus (MSSA) and Methicillin-resistant Staphylococcus aureus (MRSA) were both 1,420 µg/mL. Based on the chromatographic analysis of the crude sample and ethanol extracted propolis, it was concluded that propolis was a mixture of the BRP (SP/MG) and BRP (PR) types. The results obtained confirm an antimicrobial activity in relation to the strains of the S. aureus tested. PMID:24031749
Cabrera-Contreras, Roberto; Morelos-Ramírez, Rubén; Galicia-Camacho, Ada Nelly; Meléndez-Herrada, Enrique
Staphylococcus epidermidis strains isolated from nosocomial infections represent a serious problem worldwide. In various Mexican states several reports have shown isolates from hospitals with antibiotic resistance to methicillin. In Mexico City, there is scarce information on staphylococcal infections in hospitals. Here, our research findings are shown in a four-year period study (2006–2010) for Staphylococcus epidermidis strains. Susceptibility and/or resistance to antibiotics in SE strains were assessed by phenotypic and molecular methods as mecA gene by PCR, as well as the correlation with biofilm production for these isolates and the relationship to the infection site. Out of a total of 161 (66%) negative biofilm SE strains, just 103 (64%) SE strains were confirmed as MRSE by PCR to mecA gene. From 84 (34%) positive biofilm SE strains, 76 (91%) were confirmed as MRSE by PCR to mecA gene. Higher percentages of resistance to antibiotics and higher number of resistance markers were found in biofilm-forming clinical strains (9 to 14) than non-biofilm-forming SE strains (3 to 8). These research findings represent a guide to establish infection control programs for this hospital. PMID:23724338
Zuniga, Eveline; Melville, Priscilla A; Saidenberg, André B S; Laes, Marco A; Gonsales, Fernanda F; Salaberry, Sandra R S; Gregori, Fabio; Brandão, Paulo E; dos Santos, Franklin G B; Lincopan, Nilton E; Benites, Nilson R
This study aimed to elucidate aspects of the epidemiology of bovine subclinical mastitis through the assessment of genes encoding MSCRAMM (microbial surface components recognizing adhesive matrix molecules - a group of adhesins) and protein Bap (implicated in biofilm formation), in coagulase-positive (CPS) and coagulase-negative (CNS) Staphylococcus isolated from subclinical mastitis. Milk samples were collected for microbiological exams, somatic cell count (SCC) and a survey of the genes coding for MSCRAMM (cna, eno, ebpS, fnbA, fnbB and fib) and biofilm-associated protein Bap (bap) in 106 Staphylococcus spp. isolates using PCR. The frequencies of occurrence of eno (82.1%), fnbA (72.6%), fib (71.7%) and bap (56.6%) were higher (P < 0.0001) compared with the other assessed genes (cna, ebpS and fnbB). The higher frequency of occurrence (P < 0.005) of the bap gene in CNS compared with CPS suggests that in these species biofilm formation is an important mechanism for the persistence of the infection. The medians of the SCCs in the samples where eno, fnbA, fib and bap genes were detected were higher compared with Staphylococcus without the assessed genes (P < 0.05) and negative samples (P < 0.01), which indicated that the presence of these MSCRAMM may be related to a higher intensity of the inflammatory process.
Ramón-Peréz, Miriam L; Díaz-Cedillo, Francisco; Contreras-Rodríguez, Araceli; Betanzos-Cabrera, Gabriel; Peralta, Humberto; Rodríguez-Martínez, Sandra; Cancino-Diaz, Mario E; Jan-Roblero, Janet; Cancino Diaz, Juan C
Biofilm formation on medical and surgical devices is the main virulence factor of Staphylococcus epidermidis. A recent study has shown that norspermidine inhibits and disassembles the biofilm in the wild-type Bacillus subtilis NCBI3610 strain. In this study, the effect of norspermidine on S. epidermidis biofilm formation of clinical or commensal strains was tested. Biofilm producing strains of S. epidermidis were isolated from healthy skin (HS; n = 3), healthy conjunctiva (HC; n = 9) and ocular infection (OI; n = 19). All strains were treated with different concentrations of norspermidine, spermidine, putrescine, and cadaverine (1, 10, 25, 50 and 100 μM), and the biofilm formation was tested on microtiter plate. Besides, cell-free supernatants of S. epidermidis growth at 4 h and 40 h were analyzed by gas chromatography coupled to mass spectrometry (GC-MS) to detect norspermidine. Results showed that norspermidine at 25 μM and 100 μM prevented the biofilm formation in 45.16% (14/31) and 16.13% (5/31), respectively; only in one isolate from OI, norspermidine did not have effect. Other polyamines as spermidine, putrescine and cadaverine did not have effect on the biofilm formation of the strains tested. Norspermidine was also capable to disassemble a biofilm already formed. Norspermidine was detected in the 40 h cell-free supernatant of S. epidermidis by GC-MS. Norspermidine inhibited the biofilm development of S. epidermidis on the surface of contact lens. In this work, it was demonstrated that S. epidermidis produces and releases norspermidine causing an inhibitory effect on biofilm formation. Moreover, this is the first time showing that clinical S. epidermidis strains have different sensitivity to norspermidine, which suggest that the composition and structure of the biofilms is varied. We propose that norspermidine could potentially be used in the pre-treating of medical and surgical devices to inhibit the biofilm formation.
Schuster, Dominik; Rickmeyer, Jasmin; Gajdiss, Mike; Thye, Thorsten; Lorenzen, Stephan; Reif, Marion; Josten, Michaele; Szekat, Christiane; Melo, Luís D R; Schmithausen, Ricarda M; Liégeois, Florian; Sahl, Hans-Georg; Gonzalez, Jean-Paul J; Nagel, Michael; Bierbaum, Gabriele
The species Staphylococcus argenteus was separated recently from Staphylococcus aureus (Tong S.Y., F. Schaumburg, M.J. Ellington, J. Corander, B. Pichon, F. Leendertz, S.D. Bentley, J. Parkhill, D.C. Holt, G. Peters, and P.M. Giffard, 2015). The objective of this work was to characterise the genome of a non-human S. argenteus strain, which had been isolated from the faeces of a wild-living western lowland gorilla in Gabon, and analyse the spectrum of this species in matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The full genome sequence revealed a scarcity of virulence genes and absence of resistance genes, indicating a decreased virulence potential compared to S. aureus and the human methicillin-resistant S. argenteus isolate MSHR1132(T). Spectra obtained by MALDI-TOF MS and the analysis of available sequences in the genome databases identified several MALDI-TOF MS signals that clearly differentiate S. argenteus, the closely related Staphylococcus schweitzeri and S. aureus. In conclusion, in the absence of biochemical tests that identify the three species, mass spectrometry should be employed as method of choice.
... A396 cells and spent fermentation media exemption from the requirement of a tolerance. 180.1325 Section...-killed Burkholderia spp. strain A396 cells and spent fermentation media exemption from the requirement of...-killed Burkholderia spp. strain A396 cells and spent fermentation media in or on all food...
Calderwood, S B; Baker, M A; Carroll, P A; Michel, J L; Arbeit, R D; Ausubel, F M
We examined the utility of a PCR-based method termed cleaved amplified polymorphic sequences (CAPS) to type 35 well-characterized isolates of Staphylococcus epidermidis. The results were compared with detailed epidemiologic information and typing obtained by using pulsed-field gel electrophoresis (PFGE). To identify CAPS markers for this study, eight pairs of oligonucleotide primers corresponding to five previously sequenced S. epidermidis genes were synthesized and then used to amplify DNA sequences from the S. epidermidis strains by using PCR. Amplified products were reproducibly obtained for seven of eight primer pairs from chromosomal DNA of 33 of the 35 isolates. Seven restriction site polymorphisms were found in five of the amplified products when they were subjected to digestion with a panel of restriction endonucleases. Each fragment-enzyme combination that was polymorphic demonstrated only two alleles in the 33 S. epidermidis isolates analyzed, corresponding to the presence or absence of a single restriction site. Overall, five distinct combinations of alleles were detected and were designated CAPS types A through E. There was a close correlation between the CAPS grouping, the epidemiologic information for the strains, and grouping by PFGE following SmaI digestion of chromosomal DNA. Although PFGE analysis was more discriminatory than typing based on the limited number of CAPS markers used in this study (isolates from the same CAPS group were sometimes distributed into more than one PFGE group), no isolates from the same PFGE group were found in more than one CAPS group. The CAPS procedure was highly reproducible, in contrast to published experience with arbitrarily primed PCR. These preliminary data suggest that CAPS represents a PCR-based technique for strain typing that is highly reproducible, rapid, utilizes widely available technologies, and provides results that are relatively easy to interpret and express.
Adkins, P R F; Middleton, J R; Calcutt, M J; Stewart, G C; Fox, L K
Staphylococcus hyicus and Staphylococcus agnetis are two coagulase variable staphylococcal species that can be isolated from bovine milk and are difficult to differentiate. The objectives of this study were to characterize isolates of bovine milk origin from a collection that had previously been characterized as coagulase positive S. hyicus based on phenotypic speciation methods and to develop a PCR-based method for differentiating S. hyicus, S. agnetis, and S. aureus. Isolates (n = 62) were selected from a previous study in which milk samples were collected from cows on 15 dairy herds. Isolates were coagulase tested and speciated using housekeeping gene sequencing. A multiplex PCR to differentiate S. hyicus, S. agnetis, and S. aureus was developed. Pulsed-field gel electrophoresis was conducted to strain type isolates. Based on gene sequencing, 44/62 of the isolates were determined to be either S. agnetis (n = 43) or S. hyicus (n = 1). Overall, 88% (37/42) of coagulase positive S. agnetis isolates were found to be coagulase positive at 4 hours. Herd-level prevalence of coagulase positive S. agnetis ranged from 0 to 2.17%. Strain-typing identified 23 different strains. Six strains were identified more than once and from multiple cows within the herd. Three strains were isolated from cows at more than one time point, with 41-264 days between samplings. These data suggest that S. agnetis is likely more prevalent on dairy farms than S. hyicus Also, some S. agnetis isolates in this study appeared to be contagious and associated with persistent infections.
Spiroplasma citri is the causal agent of stubborn disease in Citrus spp., as well as the cause of diseases in numerous other plant genera. Here we report the nucleotide sequence of the 1,599,709 bp circular chromosome and two plasmids of strain R8-A2T. This information will facilitate comparative ...
Hang, Feng; Liu, Peiyi; Wang, Qinbo; Han, Jin; Wu, Zhengjun; Gao, Caixia; Liu, Zhenmin; Zhang, Hao; Chen, Wei
Paenibacillus spp. BD3526, a bacterium exhibiting a protein hydrolysis circle surrounded with an obvious precipitation zone on skim milk agar, was isolated from raw yak (Bos grunniens) milk collected in Tibet, China. Phylogenetic analysis based on 16S rRNA and whole genome sequence comparison indicated the isolate belong to the genus Paenibacillus. The strain BD3526 demonstrated strong ability to produce protease with milk clotting activity (MCA) in wheat bran broth. The protease with MCA was predominantly accumulated during the late-exponential phase of growth. The proteolytic activity (PA) of the BD3526 protease was 1.33-fold higher than that of the commercial R. miehei coagulant. A maximum MCA (6470 ± 281 SU mL(-1)) of the strain BD3526 was reached under optimal cultivation conditions. The protease with MCA was precipitated from the cultivated supernatant of wheat bran broth with ammonium sulfate and purified by anion-exchange chromatography. The molecular weight of the protease with MCA was determined as 35 kDa by sodium dodecyl sulfate-polyacrylamide gels electrophoresis (SDS-PAGE) and gelatin zymography. The cleavage site of the BD3526 protease with MCA in κ-casein was located at the Met106-Ala107 bond, as determined by mass spectrometry analysis.
Murugaiyan, Jayaseelan; Eravci, Murat; Weise, Christoph; Roesler, Uwe
Microalgae of the genus Prototheca (P.) spp are associated with rare algal infections of invertebrates termed protothecosis. Among the seven generally accepted species, P. zopfii genotype 2 (GT2) is associated with a severe form of bovine mastitis while P. blaschkeae causes the mild and sub-clinical form of mastitis. The reason behind the infectious nature of P. zopfii GT2, while genotype 1 (GT1) remains non-infectious, is not known. Therefore, in the present study we investigated the protein expression level difference between the genotypes of P. zopfii and P. blaschkeae. Cells were cultured to the mid-exponential phase, harvested, and processed for LC-MS analysis. Peptide data was acquired on an LTQ Orbitrap Velos, raw spectra were quantitatively analyzed with MaxQuant software and matching with the reference database of Chlorella variabilis and Auxenochlorella protothecoides resulted in the identification of 226 proteins. Comparison of an environmental strain with infectious strains resulted in the identification of 51 differentially expressed proteins related to carbohydrate metabolism, energy production and protein translation. The expression level of Hsp70 proteins and their role in the infectious process is worth further investigation. All mass spectrometry data are available via ProteomeXchange with identifier PXD005305. PMID:28036087
Mendoza, José Luis Hernández; Pérez, María Isabel Sánchez; Prieto, Juan Manuel González; Velásquez, Jesús DiCarlo Quiroz; Olivares, Jesús Gerardo García; Langarica, Homar Rene Gill
Abstract Sampling of agricultural soils from the Mexican northeastern region was performed to detect Trichoderma spp., genetically characterize it, and assess its potential use as a biologic control agent against Macrophomina phaseolina. M. phaseolina is a phytopathogen that attacks over 500 species of cultivated plants and causes heavy losses in the regional sorghum crop. Sampling was performed immediately after sorghum or corn harvest in an area that was approximately 170 km from the Mexico-USA border. Sixteen isolates were obtained in total. Using colony morphology and sequencing the internal transcribed spacers (ITS) 1 and 4 of 18S rDNA, 14 strains were identified as Trichoderma harzianum, T. koningiopsis and T. virens. Subsequently, their antagonistic activity against M. phaseolina was evaluated in vitro, and 11 isolates showed antagonism by competition and stopped M. phaseolina growth. In 4 of these isolates, the antibiosis phenomenon was observed through the formation of an intermediate band without growth between colonies. One strain, HTE808, was identified as Trichoderma koningiopsis and grew rapidly; when it came into contact with the M. phaseolina colony, it continued to grow and sporulated until it covered the entire petri dish. Microscopic examination confirmed that it has a high level of hyperparasitism and is thus considered to have high potential for use in the control of this phytopathogen. PMID:26691467
Pournajaf, Abazar; Ardebili, Abdollah; Goudarzi, Leyla; Khodabandeh, Mahmoud; Narimani, Tahmineh; Abbaszadeh, Hassan
Objective To evaluated the PCR for mecA gene compared with the conventional oxacillin disk diffusion method for methicillin-resistant Staphylococcus aureus (S. aureus) identification. Methods A total of 292 S. aureus strains were isolated from various clinical specimens obtained from hospitalized patients. Susceptibility test to several antimicrobial agents was performed by disk diffusion agar according to Clinical and Laboratory Standards Institute guidelines. The PCR amplification of the mecA gene was carried out in all the clinical isolates. Results Among antibiotics used in our study, penicillin showed the least anti-staphylococcal activity and vancomycin was the most effective. The rate of methicillin-resistant S. aureus prevalence determined by oxacillin disk diffusion method was 47.6%; whereas, 45.1% of S. aureus isolates were mecA- positive in the PCR assay. Conclusions This study is suggestive that the PCR for detection of mecA gene is a fast, accurate and valuable diagnostic tool, particularly in hospitals in areas where methicillin-resistant S. aureus is endemic. PMID:25183100
Deng, Yang; Liu, Junyan; Peters, Brian M; Chen, Lei; Miao, Jian; Li, Bing; Li, Lin; Chen, Dingqiang; Yu, Guangchao; Xu, Zhenbo; Shirtliff, Mark E
A retrospective study was conducted on 1,739 Staphylococcus isolates from the First Affiliated Hospital of Jinan University (FAHJU) in Guangzhou during 2001-2010. With the exception of teicoplanin and vancomycin, antimicrobial resistance was commonly observed among the isolates examined, with high resistance rates for β-lactamases (94.0% and 73.7% for penicillin and oxacillin) and resistance percentages for cefoxitin, chloramphenicol, ciprofloxacin, clindamycin, erythromycin, gentamicin, trimethoprim-sulfamethoxazole, and tetracycline ranging from 83.9% to 19.4%. Two hundred sixty-three of the 1,739 isolates were subjected to SCCmec typing and 42 to MLST, spaA, and coa typing. ST239-MRSA-III was prevalently identified along with one distinct coa type HIJKL and 2 spaA types (WGKAOMQ-t037 and WGKAQQ-t030). Class 1 integrons were commonly detected (31.6%), although none of the integron-positive MRSA strains had been isolated since 2009. The widespread detection of integron-based antimicrobial resistance determinants may further contribute to the emergence of superbugs.
Cooper, R A; Molan, P C; Harding, K G
The antibacterial action of honey in infected wounds does not depend wholly on its high osmolarity. We tested the sensitivity of 58 strains of coagulase-positive Staphylococcus aureus, isolated from infected wounds, to a pasture honey and a manuka honey. There was little variation between the isolates in their sensitivity to honey: minimum inhibitory concentrations were all between 2 and 3% (v/v) for the manuka honey and between 3 and 4% for the pasture honey. Thus, these honeys would prevent growth of S. aureus if diluted by body fluids a further seven-fold to fourteen-fold beyond the point where their osmolarity ceased to be completely inhibitory. The antibacterial action of the pasture honey relied on release of hydrogen peroxide, which in vivo might be reduced by catalase activity in tissues or blood. The action of manuka honey stems partly from a phytochemical component, so this type of honey might be more effective in vivo. Comparative clinical trials with standardized honeys are needed.
Cooper, R A; Molan, P C; Harding, K G
The antibacterial action of honey in infected wounds does not depend wholly on its high osmolarity. We tested the sensitivity of 58 strains of coagulase-positive Staphylococcus aureus, isolated from infected wounds, to a pasture honey and a manuka honey. There was little variation between the isolates in their sensitivity to honey: minimum inhibitory concentrations were all between 2 and 3% (v/v) for the manuka honey and between 3 and 4% for the pasture honey. Thus, these honeys would prevent growth of S. aureus if diluted by body fluids a further seven-fold to fourteen-fold beyond the point where their osmolarity ceased to be completely inhibitory. The antibacterial action of the pasture honey relied on release of hydrogen peroxide, which in vivo might be reduced by catalase activity in tissues or blood. The action of manuka honey stems partly from a phytochemical component, so this type of honey might be more effective in vivo. Comparative clinical trials with standardized honeys are needed. PMID:10472280
Tabbene, Olfa; Karkouch, Ines; Slimene, Imen Ben; Elfeddy, Najib; Cosette, Pascal; Mangoni, Maria-Luisa; Jouenne, Thierry; Limam, Ferid
When cultured in minimal growth medium, the B38 strain of Bacillus subtilis did not exhibit any antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) clinical isolate. Coculturing B38 strain with viable MRSA cells weakly increased antibacterial activity production (20 AU/ml). Addition of dead MRSA cells in a B38 culture, increased by 8-fold the B. subtilis strain antibacterial activity reaching 160 AU/ml against MRSA strain. This antibacterial activity recovered from cell-free supernatants was stimulated by an autoinducing compound which is sensitive to the action of proteinase K suggesting a proteinaceous nature. This compound was heat-stable till 80 °C and showed a molecular mass around 20 kDa as determined by SDS-PAGE. These results suggest that the production of antibacterial compounds by B38 strain is dependent on the amount of the autoinducing compound.
Siljamäki, Pia; Varmanen, Pekka; Kankainen, Matti; Sukura, Antti; Savijoki, Kirsi; Nyman, Tuula A
Staphylococcus epidermidis (SE) includes commensal and pathogenic strains capable of infecting humans and animals. This study reports global exoproteome profiling of bovine mastitis strain PM221 and two human strains, commensal-type ATCC12228 and sepsis-associated RP62A. We identified 451, 395, and 518 proteins from culture supernatants of PM221, ATCC12228, and RP62A, respectively. Comparison of the identified exoproteomes revealed several strain-specific differences related to secreted antigens and adhesins, higher virulence capability for RP62A, and similarities between the PM221 and RP62A exoproteomes. The majority of the identified proteins (∼80%) were predicted to be cytoplasmic, including proteins known to be associated in membrane vesicles (MVs) in Staphylococcus aureus and immunogenic/adhesive moonlighting proteins. Enrichment of MV fractions from culture supernatants and analysis of their protein composition indicated that this nonclassical protein secretion pathway was being exploited under the conditions used and that there are strain-specific differences in nonclassical protein export. In addition, several predicted cell-surface proteins were identified in the culture media. In summary, the present study is the first in-depth exoproteome analysis of SE highlighting strain-specific factors able to contribute to virulence and adaptation.
Nowakiewicz, Aneta; Zięba, Przemysław; Ziółkowska, Grażyna; Gnat, Sebastian; Muszyńska, Marta; Tomczuk, Krzysztof; Majer Dziedzic, Barbara; Ulbrych, Łukasz; Trościańczyk, Aleksandra
The objective of the study was to examine a population of free-living carnivorous mammals most commonly found in Poland (red fox, beech marten, and raccoon) for the occurrence of bacteria that are potentially pathogenic for humans and other animal species and to determine their virulence potential (the presence of selected virulence genes). From the total pool of isolates obtained (n = 328), we selected 90 belonging to species that pose the greatest potential threat to human health: Salmonella spp. (n = 19; 4.51%), Yersinia enterocolitica (n = 10; 2.37%), Listeria monocytogenes and L. ivanovii (n = 21), and Staphylococcus aureus (n = 40; 9.5%). The Salmonella spp. isolates represented three different subspecies; S. enterica subsp. enterica accounted for a significant proportion (15/19), and most of the serotypes isolated (S. Typhimurium, S. Infantis, S. Newport and S. Enteritidis) were among the 10 non-typhoidal Salmonella serotypes that are most often responsible for infections in Europe, including Poland. Y. enterococlitica was detected in the smallest percentage of animals, but 60% of strains among the isolates tested possessed the ail gene, which is responsible for attachment and invasion. Potentially pathogenic Listeria species were isolated from approx. 5% of the animals. The presence of all tested virulence genes was shown in 35% of L. monocytogenes strains, while in the case of the other strains, the genes occurred in varying numbers and configurations. The presence of the inlA, inlC, hlyA, and iap genes was noted in all strains, whereas the genes encoding PI-PLC, actin, and internalin Imo2821 were present in varying percentages (from 80% to 55%). S. aureus was obtained from 40 individuals. Most isolates possessed the hla, hld (95% for each), and hlb (32.5%) genes encoding hemolysins as well as the gene encoding leukotoxin lukED (70%). In a similar percentage of strains (77.5%), the presence of at least one gene encoding enterotoxin was found, with 12
Nowakiewicz, Aneta; Zięba, Przemysław; Ziółkowska, Grażyna; Gnat, Sebastian; Muszyńska, Marta; Tomczuk, Krzysztof; Majer Dziedzic, Barbara; Ulbrych, Łukasz; Trościańczyk, Aleksandra
The objective of the study was to examine a population of free-living carnivorous mammals most commonly found in Poland (red fox, beech marten, and raccoon) for the occurrence of bacteria that are potentially pathogenic for humans and other animal species and to determine their virulence potential (the presence of selected virulence genes). From the total pool of isolates obtained (n = 328), we selected 90 belonging to species that pose the greatest potential threat to human health: Salmonella spp. (n = 19; 4.51%), Yersinia enterocolitica (n = 10; 2.37%), Listeria monocytogenes and L. ivanovii (n = 21), and Staphylococcus aureus (n = 40; 9.5%). The Salmonella spp. isolates represented three different subspecies; S. enterica subsp. enterica accounted for a significant proportion (15/19), and most of the serotypes isolated (S. Typhimurium, S. Infantis, S. Newport and S. Enteritidis) were among the 10 non-typhoidal Salmonella serotypes that are most often responsible for infections in Europe, including Poland. Y. enterococlitica was detected in the smallest percentage of animals, but 60% of strains among the isolates tested possessed the ail gene, which is responsible for attachment and invasion. Potentially pathogenic Listeria species were isolated from approx. 5% of the animals. The presence of all tested virulence genes was shown in 35% of L. monocytogenes strains, while in the case of the other strains, the genes occurred in varying numbers and configurations. The presence of the inlA, inlC, hlyA, and iap genes was noted in all strains, whereas the genes encoding PI-PLC, actin, and internalin Imo2821 were present in varying percentages (from 80% to 55%). S. aureus was obtained from 40 individuals. Most isolates possessed the hla, hld (95% for each), and hlb (32.5%) genes encoding hemolysins as well as the gene encoding leukotoxin lukED (70%). In a similar percentage of strains (77.5%), the presence of at least one gene encoding enterotoxin was found, with 12
Bouvet, A; Fournier, J M; Audurier, A; Branger, C; Orsoni, A; Girard, C
An outbreak of nosocomial infections occurring in a postoperative intensive care unit was caused by a single strain of oxacillin-resistant Staphylococcus aureus. Six patients were infected, or colonized, by this strain, which was traced by using the following four epidemiological markers: antibiogram, bacteriophage type, capsular polysaccharide type, and esterase electrophoretic type. This strain was compared with S. aureus isolates obtained from the noses of 13 carriers from a group of 42 staff members. A good correlation in terms of phenotypic markers was found between the epidemic strain and a strain isolated from one carrier. Both exhibited the same pattern of multiple resistance as well as the same phage type, 77, capsular polysaccharide type, 5, and esterase electrophoretic type, 6. In contrast, an oxacillin-resistant strain, isolated from another carrier, differed from the epidemic strain by susceptibility to rifampin and by susceptibility to four additional bacteriophages. The other 11 strains isolated from carriers were susceptible to oxacillin and exhibited widely different phenotypes. These results confirm the interest of using several epidemiological markers to trace the spread of epidemic S. aureus strains and to delineate the carrier strains. PMID:2199498
Lozano, Carmen; García-Migura, Lourdes; Aspiroz, Carmen; Zarazaga, Myriam; Torres, Carmen; Aarestrup, Frank Møller
An expansion of a previously described plasmid classification was performed and used to reveal the plasmid content of a collection of 92 Staphylococcus aureus strains of different origins. rep genes of other genera were detected in Staphylococcus. S1 pulsed-field gel electrophoresis (PFGE) hybridizations were performed with 18 representative S. aureus strains, and a high number of plasmids of different sizes and organizations were detected.
Fernandes, Tiago Gomes; de Mesquita, Amanda Rafaela Carneiro; Randau, Karina Perrelli; Franchitti, Adelisa Alves; Ximenes, Eulália Azevedo
The aim of this study was to evaluate the antimicrobial activity of aqueous extract of Psidium guineense Swartz (Araçá-do-campo) and five antimicrobials (ampicillin, amoxicillin/clavulanic acid, cefoxitin, ciprofloxacin, and meropenem) against twelve strains of Staphylococcus aureus with a resistant phenotype previously determined by the disk diffusion method. Four S. aureus strains showed resistance to all antimicrobial agents tested and were selected for the study of the interaction between aqueous extract of P. guineense and antimicrobial agents, by the checkerboard method. The criteria used to evaluate the synergistic activity were defined by the fractional inhibitory concentration index (FICI). All S. aureus strains were susceptible to P. guineense as determined by the microdilution method. The combination of the P. guineense extract with the antimicrobial agents resulted in an eight-fold reduction in the MIC of these agents, which showed a FICI ranging from 0.125 to 0.5, suggesting a synergistic interaction against methicillin-resistant Staphylococcus aureus (MRSA) strains. The combination of the aqueous extract of P. guineense with cefoxitin showed the lowest FICI values. This study demonstrated that the aqueous extract of P. guineense combined with beta lactamics antimicrobials, fluoroquinolones, and carbapenems, acts synergistically by inhibiting MRSA strains.
Fernandes, Tiago Gomes; de Mesquita, Amanda Rafaela Carneiro; Randau, Karina Perrelli; Franchitti, Adelisa Alves; Ximenes, Eulália Azevedo
The aim of this study was to evaluate the antimicrobial activity of aqueous extract of Psidium guineense Swartz (Araçá-do-campo) and five antimicrobials (ampicillin, amoxicillin/clavulanic acid, cefoxitin, ciprofloxacin, and meropenem) against twelve strains of Staphylococcus aureus with a resistant phenotype previously determined by the disk diffusion method. Four S. aureus strains showed resistance to all antimicrobial agents tested and were selected for the study of the interaction between aqueous extract of P. guineense and antimicrobial agents, by the checkerboard method. The criteria used to evaluate the synergistic activity were defined by the fractional inhibitory concentration index (FICI). All S. aureus strains were susceptible to P. guineense as determined by the microdilution method. The combination of the P. guineense extract with the antimicrobial agents resulted in an eight-fold reduction in the MIC of these agents, which showed a FICI ranging from 0.125 to 0.5, suggesting a synergistic interaction against methicillin-resistant Staphylococcus aureus (MRSA) strains. The combination of the aqueous extract of P. guineense with cefoxitin showed the lowest FICI values. This study demonstrated that the aqueous extract of P. guineense combined with beta lactamics antimicrobials, fluoroquinolones, and carbapenems, acts synergistically by inhibiting MRSA strains. PMID:22619603
Liang, Chunguang; Schaack, Dominik; Srivastava, Mugdha; Gupta, Shishir K; Sarukhanyan, Edita; Giese, Anne; Pagels, Martin; Romanov, Natalie; Pané-Farré, Jan; Fuchs, Stephan; Dandekar, Thomas
Staphylococcus aureus is an important model organism and pathogen. This S. aureus proteome overview details shared and specific proteins and selected virulence-relevant protein complexes from representative strains of all three major clades. To determine the strain distribution and major clades we used a refined strain comparison combining ribosomal RNA, MLST markers, and looking at highly-conserved regions shared between strains. This analysis shows three sub-clades (A-C) for S. aureus. As calculations are complex and strain annotation is quite time consuming we compare here key representatives of each clade with each other: model strains COL, USA300, Newman, and HG001 (clade A), model strain N315 and Mu50 (clade B) and ED133 and MRSA252 (clade C). We look at these individual proteomes and compare them to a background of 64 S. aureus strains. There are overall 13,284 S. aureus proteins not part of the core proteome which are involved in different strain-specific or more general complexes requiring detailed annotation and new experimental data to be accurately delineated. By comparison of the eight representative strains, we identify strain-specific proteins (e.g., 18 in COL, 105 in N315 and 44 in Newman) that characterize each strain and analyze pathogenicity islands if they contain such strain-specific proteins. We identify strain-specific protein repertoires involved in virulence, in cell wall metabolism, and phosphorylation. Finally we compare and analyze protein complexes conserved and well-characterized among S. aureus (a total of 103 complexes), as well as predict and analyze several individual protein complexes, including structure modeling in the three clades.
Liang, Chunguang; Schaack, Dominik; Srivastava, Mugdha; Gupta, Shishir K.; Sarukhanyan, Edita; Giese, Anne; Pagels, Martin; Romanov, Natalie; Pané-Farré, Jan; Fuchs, Stephan; Dandekar, Thomas
Staphylococcus aureus is an important model organism and pathogen. This S. aureus proteome overview details shared and specific proteins and selected virulence-relevant protein complexes from representative strains of all three major clades. To determine the strain distribution and major clades we used a refined strain comparison combining ribosomal RNA, MLST markers, and looking at highly-conserved regions shared between strains. This analysis shows three sub-clades (A–C) for S. aureus. As calculations are complex and strain annotation is quite time consuming we compare here key representatives of each clade with each other: model strains COL, USA300, Newman, and HG001 (clade A), model strain N315 and Mu50 (clade B) and ED133 and MRSA252 (clade C). We look at these individual proteomes and compare them to a background of 64 S. aureus strains. There are overall 13,284 S. aureus proteins not part of the core proteome which are involved in different strain-specific or more general complexes requiring detailed annotation and new experimental data to be accurately delineated. By comparison of the eight representative strains, we identify strain-specific proteins (e.g., 18 in COL, 105 in N315 and 44 in Newman) that characterize each strain and analyze pathogenicity islands if they contain such strain-specific proteins. We identify strain-specific protein repertoires involved in virulence, in cell wall metabolism, and phosphorylation. Finally we compare and analyze protein complexes conserved and well-characterized among S. aureus (a total of 103 complexes), as well as predict and analyze several individual protein complexes, including structure modeling in the three clades. PMID:28248218
Guillemot, Didier; Bonacorsi, Stephane; Blanchard, John S; Weber, Philippe; Simon, Sylvie; Guesnon, Bruno; Bingen, Edouard; Carbon, Claude
We examined factors associated with penicillinase production by nasal carriage Staphylococcus aureus strains in 648 children aged 3 to 6 years attending 20 randomly sampled playschools. The children were prospectively monitored for drug use and medical events for 6 months and were then screened for S. aureus carriage. Isolates were tested for their susceptibility to penicillin G and methicillin, and penicillinase production by methicillin-susceptible, penicillin-resistant strains was quantified. S. aureus was isolated from 166 children (25.6%). Exposure to amoxicillin-clavulanate during the previous 3 months was associated with higher penicillinase production by penicillin-resistant, methicillin-susceptible strains (odds ratio, 3.6; P = 0.03). These results suggest that use of the amoxicillin-clavulanate combination could induce a herd selection process of S. aureus strains producing higher levels of penicillinase.
Lagos, Jaime; Alarcón, Pedro; Benadof, Dona; Ulloa, Soledad; Fasce, Rodrigo; Tognarelli, Javier; Aguayo, Carolina; Araya, Pamela; Parra, Bárbara; Olivares, Berta; Hormazábal, Juan Carlos; Fernández, Jorge
We report the first description of a rare catalase-negative strain of Staphylococcus aureus in Chile. This new variant was isolated from blood and synovial tissue samples of a pediatric patient. Sequencing analysis revealed that this catalase-negative strain is related to ST10 strain, which has earlier been described in relation to S. aureus carriers. Interestingly, sequence analysis of the catalase gene katA revealed presence of a novel nonsense mutation that causes premature translational truncation of the C-terminus of the enzyme leading to a loss of 222 amino acids. Our study suggests that loss of catalase activity in this rare catalase-negative Chilean strain is due to this novel nonsense mutation in the katA gene, which truncates the enzyme to just 283 amino acids.
Holá, V; Růzicka, F; Votava, M
The adhering capability and biofilm growth facilitate staphylococcal colonization of surfaces of damaged tissues and foreign bodies. Biofilm-forming bacteria are more resistant to immune system activities, mechanical effects of blood flow and other adverse effects, e.g. those due to antibiotics. Minimal inhibitory concentrations (MICs) were compared for two groups of Staphylococcus epidermidis strains isolated from blood cultures. Group 1 included biofilm positive strains whose biofilm-forming potential was revealed by both phenotypic and genotypic methods. Group 2 included strains without biofilm-forming potential. The comparison of MICs for selected antibiotics showed higher resistance of biofilm positive compared to biofilm negative strains. The difference was evident particularly for oxacillin, tetracycline, co-trimoxazole and gentamicin.
Carregaro, Adriano Bonfim; Santurio, Deise Flores; de Sá, Mariangela Facco; Santurio, Janio Moraes; Alves, Sydney Hartz
This study evaluated the in vitro antibacterial activity of essential oils from Lippia graveolens (Mexican oregano), Origanum vulgaris (oregano), Thymus vulgaris (thyme), Rosmarinus officinalis (rosemary), Cymbopogon nardus (citronella), Cymbopogon citratus (lemongrass), and Eucalyptus citriodora (eucalyptus) against Escherichia coli (n = 22) strains isolated from Alouatta spp. feces. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for each isolate using the broth microdilution technique. Essential oils of Mexican oregano (MIC mean = 1818 μg mL−1; MBC mean = 2618 μg mL−1), thyme (MIC mean = 2618 μg mL−1; MBC mean = 2909 μg mL−1), and oregano (MIC mean = 3418 μg mL−1; MBC mean = 4800 μg mL−1) showed the best antibacterial activity, while essential oils of eucalyptus, rosemary, citronella, and lemongrass displayed no antibacterial activity at concentrations greater than or equal to 6400 μg mL−1. Our results confirm the antimicrobial potential of some essential oils, which deserve further research. PMID:27313638
Lara, Valéria Maria; Carregaro, Adriano Bonfim; Santurio, Deise Flores; de Sá, Mariangela Facco; Santurio, Janio Moraes; Alves, Sydney Hartz
This study evaluated the in vitro antibacterial activity of essential oils from Lippia graveolens (Mexican oregano), Origanum vulgaris (oregano), Thymus vulgaris (thyme), Rosmarinus officinalis (rosemary), Cymbopogon nardus (citronella), Cymbopogon citratus (lemongrass), and Eucalyptus citriodora (eucalyptus) against Escherichia coli (n = 22) strains isolated from Alouatta spp. feces. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for each isolate using the broth microdilution technique. Essential oils of Mexican oregano (MIC mean = 1818 μg mL(-1); MBC mean = 2618 μg mL(-1)), thyme (MIC mean = 2618 μg mL(-1); MBC mean = 2909 μg mL(-1)), and oregano (MIC mean = 3418 μg mL(-1); MBC mean = 4800 μg mL(-1)) showed the best antibacterial activity, while essential oils of eucalyptus, rosemary, citronella, and lemongrass displayed no antibacterial activity at concentrations greater than or equal to 6400 μg mL(-1). Our results confirm the antimicrobial potential of some essential oils, which deserve further research.
Kawada-Matsuo, Miki; Shammi, Fariha; Oogai, Yuichi; Nakamura, Norifumi; Sugai, Motoyuki; Komatsuzawa, Hitoshi
Exfoliative toxin (ET) produced by Staphylococcus aureus is closely associated with the onset of bullous impetigo. To date, three ETs (ETA, ETB and ETD) have been identified. The gene encoding ETB is located in a plasmid designated pETB. Bacteriocin synthesis genes are also located in this plasmid and pETB-positive strains reportedly produce the C55 bacteriocin. In this study, the antibacterial activity against S. aureus strains of the bacteriocin produced by the pETB-positive strain TY4 was investigated. This bacteriocin demonstrated antibacterial activity against all pETB-negative but not pETB-positive strains, including TY4. Additionally, a TY4- strain from which the pETB plasmid had been deleted exhibited susceptibility to the bacteriocin. Further experiments revealed that two immunity factors (orf 46-47 and orf 48) downstream of the bacteriocin synthesis genes in the pETB plasmid are associated with immunity against the bacteriocin produced by TY4. The TY4- with orf46-47 strain exhibited complete resistance to bacteriocin, whereas the TY4- with orf48 strain exhibited partial resistance. Whether bacteriocin affects the proportion of each strain when co-cultured with S. aureus strains was also investigated. When TY4 or TY4- was co-cultured with 209P strain, which is susceptible to the bacteriocin, the proportion of 209P co-cultured with TY4 was significantly less than when 209P was co-cultured with TY4-, whereas the proportion of TY4- with orf46-48 co-cultured with TY4 was greater than with TY4-. These results suggest that the C55 bacteriocin produced by pETB-positive strains affects the proportion of each strain when pETB-positive and -negative strains co-exist.
Burrough, Eric; Strait, Erin; Kinyon, Joann; Bower, Leslie; Madson, Darin; Schwartz, Kent; Frana, Timothy; Songer, J Glenn
Multiple Brachyspira spp. can colonize the porcine colon, and the presence of the strongly beta-hemolytic Brachyspira hyodysenteriae is typically associated with clinical swine dysentery. Recently, several Brachyspira spp. have been isolated from the feces of pigs with clinical disease suggestive of swine dysentery, yet these isolates were not identified as B. hyodysenteriae by genotypic or phenotypic methods. This study used a mouse model of swine dysentery to compare the pathogenic potential of seventeen different Brachyspira isolates including eight atypical clinical isolates, six typical clinical isolates, the standard strain of B. hyodysenteriae (B204), and reference strains of Brachyspira intermedia and Brachyspira innocens. Results revealed that strongly beta-hemolytic isolates induced significantly greater cecal inflammation than weakly beta-hemolytic isolates regardless of the genetic identification of the isolate, and that strongly beta-hemolytic isolates identified as 'Brachyspira sp. SASK30446' and B. intermedia by PCR produced lesions indistinguishable from those caused by B. hyodysenteriae in this model.
Sung, Julia M-L; Lloyd, David H; Lindsay, Jodi A
Staphylococcus aureus is a commensal and pathogen of several mammalian species, particularly humans and cattle. We aimed to (i) identify S. aureus genes associated with host specificity, (ii) determine the relatedness of human and animal isolates, and (iii) identify whether human and animal isolates typically exchanged mobile genetic elements encoding virulence and resistance genes. Using a well-validated seven-strain S. aureus microarray, we compared 56 UK S. aureus isolates that caused infection in cows, horses, goats, sheep and a camel with 161 human S. aureus isolates from healthy carriers and community acquired infections in the UK. We had previously shown that human isolates are clustered into ten dominant and a few minor lineages, each with unique combinations of surface proteins predicted to bind to human proteins. We found that the animal-associated S. aureus clustered into ten lineages, with 61 % assigned to four lineages, ST151, ST771, ST130 and ST873, that were unique to animals. The majority of bovine mastitis was caused by isolates of lineage ST151, ST771 and ST97, but a few human lineages also caused mastitis. S. aureus isolated from horses were more likely to cluster into human-associated lineages, with 54 % of horse-associated S. aureus assigned to the human clusters CC1, CC8 and CC22; along with the presence of some multi-drug resistant strains, this suggests a human origin. This is the most comprehensive genetic comparison of human versus animal S. aureus isolates conducted, and because we used a whole-genome approach we could estimate the key genes with the greatest variability that are associated with host specificity. Several genes conserved in all human isolates were variable or missing in one or more animal lineages, including the well-characterized lineage specific genes fnbA, fnbB and coa. Interestingly, genes carried on mobile genetic elements (MGEs) such as chp, scn and sak were less common in animal S. aureus isolates, and bap was not
Cheng, Jinghua; Wang, Yan; Cao, Yongzhong; Yan, Wenguang; Niu, Xiaosai; Zhou, Liping; Chen, Jianhao; Sun, Ying; Li, Chenxi; Zhang, Xiaorong; Wu, Yantao
The distribution of 18 staphylococcal enterotoxin (SE) or SE-like (SEl) genes in Staphylococcus aureus strains from different sources in east China was investigated. Among all 496 S. aureus strains, 291 strains carried one or more SE genes. The more frequently occurred genes were sea, seb, seg, selk, sell, selm, selo, and seq; the less frequent occurred genes were sec, selj, and ser. The classic SE genes and the enterotoxin gene cluster (egc) (seg, sei, selm, seln, selo, and/or selu) accounted for 25.67% and 61.68% of all detected genes, respectively. There were three gene clusters (egc, sea-sek-seq, and sed-sej-ser), of which the egc cluster was the important one that could generate novel complexes, and the sea-sek-seq cluster was a close relative to the hospital-acquired methicillin-resistant S. aureus. The SE gene distributions were different among strains of different sources and formed diverse toxin gene profiles. The human- and foodborne-origin strains harbored classic and novel SE and SEl genes, whereas animal-origin strains harbored egc and other novel SE and SEl genes mainly. The foodborne- and human-origin strains were the main dangerous factors of classic staphylococcal foodborne poisoning, whereas the strains (especially from animals) that carried egc and other novel genes mainly should be new potential dangerous factors for food safety.
Robinson, Gwen L; Harris, Anthony D; Morgan, Daniel J; Pineles, Lisa; Belton, Beverly M; Johnson, J Kristie
This study determined the survivability of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) for extended periods of time and temperatures using a standard swab for assessment. Our study showed that transportation in Liquid Amies medium could be performed at room temperature or 4°C for up to 14 days without a decrease in recovery of MRSA or VRE.
Robinson, Gwen L.; Harris, Anthony D.; Morgan, Daniel J.; Pineles, Lisa; Belton, Beverly M.
This study determined the survivability of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) for extended periods of time and temperatures using a standard swab for assessment. Our study showed that transportation in Liquid Amies medium could be performed at room temperature or 4°C for up to 14 days without a decrease in recovery of MRSA or VRE. PMID:22535993
Verschuere, L; Heang, H; Criel, G; Sorgeloos, P; Verstraete, W
In this study Vibrio proteolyticus CW8T2 has been identified as a virulent pathogen for Artemia spp. Its infection route has been visualized with transmission electron microscopy. The pathogen affected microvilli and gut epithelial cells, disrupted epithelial cell junctions, and reached the body cavity, where it devastated cells and tissues. In vivo antagonism tests showed that preemptive colonization of the culture water with nine selected bacterial strains protected Artemia juveniles against the pathogenic effects. Two categories of the selected strains could be distinguished: (i) strains providing total protection, as no mortality occurred 2 days after the experimental infection with V. proteolyticus CW8T2, with strain LVS8 as a representative, and (ii) strains providing partial protection, as significant but not total mortality was observed, with strain LVS2 as a representative. The growth of V. proteolyticus CW8T2 in the culture medium was slowed down in the presence of strains LVS2 and LVS8, but growth suppression was distinctly higher with LVS8 than with LVS2. It was striking that the strains that gave only partial protection against the pathogen in the in vivo antagonism test showed also a restricted capability to colonize the Artemia compared to the strains providing total protection. The in vivo antagonism tests and the filtrate experiments showed that probably no extracellular bacterial compounds were involved in the protective action but that the living cells were required to protect Artemia against V. proteolyticus CW8T2.
Ishii, Kenichi; Tabuchi, Fumiaki; Matsuo, Miki; Tatsuno, Keita; Sato, Tomoaki; Okazaki, Mitsuhiro; Hamamoto, Hiroshi; Matsumoto, Yasuhiko; Kaito, Chikara; Aoyagi, Tetsuji; Hiramatsu, Keiichi; Kaku, Mitsuo; Moriya, Kyoji; Sekimizu, Kazuhisa
The development of vancomycin (VCM) resistance in Staphylococcus aureus threatens global health. Studies of the VCM-resistance mechanism and alternative therapeutic strategies are urgently needed. We mutagenized S. aureus laboratory strains and methicillin-resistant S. aureus (MRSA) with ethyl methanesulfonate, and isolated mutants that exhibited high resistance to VCM (minimum inhibitory concentration = 32 μg/ml). These VCM-resistant strains were sensitive to linezolid and rifampicin, and partly to arbekacin and daptomycin. Beta-lactams had synergistic effects with VCM against these mutants. VCM-resistant strains exhibited a 2-fold increase in the cell wall thickness. Several genes were commonly mutated among the highly VCM-resistant mutants. These findings suggest that MRSA has a potential to develop high VCM resistance with cell wall thickening by the accumulation of mutations.
He, Wenqiang; Liu, Yuqing; Qi, Jing; Chen, Hongbin; Zhao, Chunjiang; Zhang, Feifei; Li, Henan; Wang, Hui
To determine whether methicillin-susceptible S. aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) are present in commercial pig farms and food products from supermarkets in China, we characterized S. aureus isolates from 250 samples associated with swine and animal-related food products in Shandong Province. The isolates were characterized by susceptibility testing, toxin gene detection, pulse-field gel electrophoresis (PFGE), multilocus sequence typing, and spa typing. MRSA were identified and typed by the staphylococcal cassette chromosome mec (SCCmec). The prevalence of S. aureus among all samples was 19.6% (49/250). MRSA and MSSA accounted for 16.7% (20/120) and 8.3% (10/120), respectively, of swine feces samples. Only MSSA was detected from swine carcass, pork, chicken, and raw milk, accounting for 15% (6/40), 10% (3/30), 20% (6/30), and 13.3% (4/30), respectively. The predominant MRSA clone was ST9-t899 SCCmecIVb/PFGE A (70.0%, 14/20). Among the MSSA isolates, ST9-t899/PFGE A was the most prevalent (27.6%), followed by ST15-t084 (17.2%), ST97-t2756 (10.3%), ST1-t127 (6.9%), and ST398-t899 (3.5%). Some lineages were found that are commonly detected in humans (e.g., ST1, ST5, ST7, ST59, ST88) or are human-specific (e.g., ST15). The toxin genes sec, seh, and enterotoxin gene cluster (egc) were significantly more prevalent among isolates of lineage ST9 (p<0.001) compared to other lineages, and the ST9 isolates were more resistant to erythromycin, clindamycin, ciprofloxacin, chloramphenicol, and gentamicin. The same lineage was identified from different sample types, indicating circulation of the related strains within the area of study. In conclusion, swine and food products of animal origin carried S. aureus, and the predominant ST9 clone possesses a multidrug-resistance profile and a high prevalence of sec, seh, and egc enterotoxin genes.
Snoussi, Mejdi; Noumi, Emira; Trabelsi, Najla; Flamini, Guido; Papetti, Adele; De Feo, Vincenzo
Chemical composition, antioxidant and anti-Vibrio spp. activities of the essential oil isolated from the aerial parts of Mentha spicata L. (spearmint) are investigated in the present study. The effect of the essential oil on Vibrio spp. biofilm inhibition and eradication was tested using the XTT assay. A total of 63 chemical constituents were identified in spearmint oil using GC/MS, constituting 99.9% of the total identified compounds. The main components were carvone (40.8% ± 1.23%) and limonene (20.8% ± 1.12%). The antimicrobial activity against 30 Vibrio spp. strains (16 species) was evaluated by disc diffusion and microdilution assays. All microorganisms were strongly affected, indicating an appreciable antimicrobial potential of the oil. Moreover, the investigated oil exhibited high antioxidant potency, as assessed by four different tests in comparison with BHT. The ability of the oil, belonging to the carvone chemotype, to inhibit or reduce Vibrio spp. biofilm warrants further investigation to explore the use of natural products in antibiofilm adhesion and reinforce the possibility of its use in the pharmaceutical or food industry as a natural antibiotic and seafood preservative against Vibrio contamination.
Hwang, William C; Xu, Qingping; Wu, Bainan; Godzik, Adam
Flavin-containing Monooxygenase (FMO) catalyzed the oxygenation of broad spectrum of substrates. FMO can also serve as biocatalysts in the Baeyer-Villiger reaction in organic synthesis. Here, we report the high-resolution crystal structure of a Baeyer-Villiger Flavin-containing Monooxygenase (BVFMO) from methicillin- and vancomycin-resistant Staphylococcus aureus strain MU50. The structure of S. aureus FMO should facilitate further development of BVFMO as biocatalysts. A possible role of S. aureus FMO in methicillin and vancomycin resistance is discussed. Proteins 2014. © 2014 Wiley Periodicals, Inc.
Hara, Takeshi; Matsui, Hiroshi; Shimizu, Hironori
Diacetyl (2,3-butanedione) is a key contributor to unpleasant odors emanating from the axillae, feet, and head regions. To investigate the mechanism of diacetyl generation on human skin, resident skin bacteria were tested for the ability to produce diacetyl via metabolism of the main organic acids contained in human sweat. l-Lactate metabolism by Staphylococcus aureus and Staphylococcus epidermidis produced the highest amounts of diacetyl, as measured by high-performance liquid chromatography. Glycyrrhiza glabra root extract (GGR) and α-tocopheryl-l-ascorbate-2-O-phosphate diester potassium salt (EPC-K1), a phosphate diester of α-tocopherol and ascorbic acid, effectively inhibited diacetyl formation without bactericidal effects. Moreover, a metabolic flux analysis revealed that GGR and EPC-K1 suppressed diacetyl formation by inhibiting extracellular bacterial conversion of l-lactate to pyruvate or by altering intracellular metabolic flow into the citrate cycle, respectively, highlighting fundamentally distinct mechanisms by GGR and EPC-K1 to suppress diacetyl formation. These results provide new insight into diacetyl metabolism by human skin bacteria and identify a regulatory mechanism of diacetyl formation that can facilitate the development of effective deodorant agents. PMID:25390046
Kokkori, Sofia; Apostolidi, Maria; Tsakris, Athanassios; Pournaras, Spyros
Linezolid-dependent growth was recently reported in Staphylococcus epidermidis clinical strains carrying mutations associated with linezolid resistance. To investigate this unexpected behavior at the molecular level, we isolated active ribosomes from one of the linezolid-dependent strains and we compared them with ribosomes isolated from a wild-type strain. Both strains were grown in the absence and presence of linezolid. Detailed biochemical and structural analyses revealed essential differences in the function and structure of isolated ribosomes which were assembled in the presence of linezolid. The catalytic activity of peptidyltransferase was found to be significantly higher in the ribosomes derived from the linezolid-dependent strain. Interestingly, the same ribosomes exhibited an abnormal ribosomal subunit dissociation profile on a sucrose gradient in the absence of linezolid, but the profile was restored after treatment of the ribosomes with an excess of the antibiotic. Our study suggests that linezolid most likely modified the ribosomal assembly procedure, leading to a new functional ribosomal population active only in the presence of linezolid. Therefore, the higher growth rate of the partially linezolid-dependent strains could be attributed to the functional and structural adaptations of ribosomes to linezolid. PMID:24890589
Rahimi, Fateh; Shokoohizadeh, Leili
Methicillin resistant Staphylococcus aureus is one of the most common causes of a variety of infections ranging from wound infections to urinary tract infections (UTI) in hospital and community. In this study during 3 years we characterized the antibiotic resistance patterns of 491 hospital acquired MRSA and community associated MRSA strains by the guidelines of clinical and laboratory standard institute. A combination of high resolution PhP typing method and SCCmec typing were used for clonal dissemination of isolates. Among all 491 MRSA strains, diverse PhP types consisting of 29 common types (CTs) and 4 single types (STs) and also 2 different SCCmec types (III and IVa) were detected. In addition, 18 CTs were common among CA- and HA-MRSA strains and the presence of all 4 STs was limited to HA-MRSA strains. All isolates were resistant to penicillin and high level resistance was observed against ciprofloxacin, erythromycin, tobramycin and kanamycin and the rate of resistance to most of the antibiotic tested among HA-MRSA was significantly higher than CA-MRSA isolates. Moreover, all isolates showed susceptibility to linezolid, vancomycin and quinupristin-dalfopristin and very low resistance to fusidic acid, nitrofurantoin and chloramphenicol were detected. Our findings illustrated the increasing rate of clonal dissemination and persistence of highly antibiotic resistant CA-MRSA strains in Tehran hospitals, and also indicated the important role of the hospitals as the reservoir of MRSA strains.
Kokkori, Sofia; Apostolidi, Maria; Tsakris, Athanassios; Pournaras, Spyros; Stathopoulos, Constantinos; Dinos, George
Linezolid-dependent growth was recently reported in Staphylococcus epidermidis clinical strains carrying mutations associated with linezolid resistance. To investigate this unexpected behavior at the molecular level, we isolated active ribosomes from one of the linezolid-dependent strains and we compared them with ribosomes isolated from a wild-type strain. Both strains were grown in the absence and presence of linezolid. Detailed biochemical and structural analyses revealed essential differences in the function and structure of isolated ribosomes which were assembled in the presence of linezolid. The catalytic activity of peptidyltransferase was found to be significantly higher in the ribosomes derived from the linezolid-dependent strain. Interestingly, the same ribosomes exhibited an abnormal ribosomal subunit dissociation profile on a sucrose gradient in the absence of linezolid, but the profile was restored after treatment of the ribosomes with an excess of the antibiotic. Our study suggests that linezolid most likely modified the ribosomal assembly procedure, leading to a new functional ribosomal population active only in the presence of linezolid. Therefore, the higher growth rate of the partially linezolid-dependent strains could be attributed to the functional and structural adaptations of ribosomes to linezolid.
Thomsen, Natalie A; Hammer, Katherine A; Riley, Thomas V; Van Belkum, Alex; Carson, Christine F
The aim of this study was to seek additional data on the antimicrobial susceptibility of Staphylococcus spp. after habituation to low levels of the topical antimicrobial agent tea tree (Melaleuca alternifolia) oil. Meticillin-susceptible Staphylococcus aureus (MSSA), meticillin-resistant S. aureus (MRSA) and coagulase-negative staphylococci (CoNS) were habituated to 0.075% tea tree oil for 3 days. Subsequently, the susceptibility of five isolates each of MSSA, MRSA and CoNS to fusidic acid, mupirocin, chloramphenicol, linezolid and vancomycin was determined by Etest, and susceptibility to tea tree oil, terpinen-4-ol, carvacrol and triclosan was determined by agar dilution. Following habituation to 0.075% tea tree oil, antimicrobial MICs differed between control and habituated isolates on 33 occasions (out of a possible 150), with MICs being higher in habituated isolates on 22 occasions. Using clinical breakpoint criteria, one MSSA isolate changed susceptibility category from vancomycin-susceptible (MIC=2 μg/mL) to intermediate susceptibility (MIC=3 μg/mL) after habituation in one of two replicates. For the non-antibiotic antimicrobial agents, MICs of habituated and control isolates differed on 12 occasions (out of a possible 120); 10 occasions in MRSA and 2 occasions in MSSA. MICs were higher for habituated isolates on five occasions. However, all the differences were one serial dilution only and were not regarded as significant. Habituation to sublethal concentrations of tea tree oil led to minor changes in MICs of antimicrobial agents, only one of which may have been clinically relevant. There is no evidence to suggest that tea tree oil induces resistance to antimicrobial agents.
Aristil, Junior; Venturini, Giovanni; Spada, Alberto
Subsistence farming and poor storage facilities favor toxigenic fungal contamination and mycotoxin accumulation in staple foods from tropical countries such as Haiti. The present preliminary study was designed to evaluate the occurrence of toxigenic fungi in Haitian foodstuffs to define the mycotoxin risk associated with Haitian crops. The objectives of this research were to determine the distribution of toxigenic fungi in the Haitian crops maize, moringa, and peanut seeds and to screen Aspergillus section Flavi (ASF) isolates for production of aflatoxins B1 and G1 in vitro. Maize, moringa, and peanut samples were contaminated by potential toxigenic fungal taxa, mainly ASF and Fusarium spp. The isolation frequency of Aspergillus spp. and Fusarium spp. was influenced by locality and thus by farming systems, storage systems, and weather conditions. Particularly for ASF in peanut and maize samples, isolation frequencies were directly related to the growing season length. The present study represents the first report of contamination by toxigenic fungi and aflatoxin in moringa seeds, posing concerns about the safety of these seeds, which people in Haiti commonly consume. Most (80%) of the Haitian ASF strains were capable of producing aflatoxins, indicating that Haitian conditions clearly favor the colonization of toxigenic ASF strains over atoxigenic strains. ASF strains producing both aflatoxins B1 and G1 were found. Understanding the distribution of toxigenic ASF in Haitian crops and foodstuffs is important for determining accurate toxicological risks because the toxic profile of ASF is species specific. The occurrence of toxigenic fungi and the profiles of the ASF found in various crops highlight the need to prevent formation of aflatoxins in Haitian crops. This study provides relevant preliminary baseline data for guiding the development of legislation regulating the quality and safety of crops in this low-income country.
Camassola, Marli; da Rosa, Letícia O.; Calloni, Raquel; Gaio, Tamara A.; Dillon, Aldo J.P.
Pleurotus species secrete phenol oxidase enzymes: laccase (Lcc) and manganese peroxidase (MnP). New genotypes of these species show potential to be used in processes aiming at the degradation of phenolic compounds, polycyclic aromatic hydrocarbons and dyes. Hence, a screening of some strains of Pleurotus towards Lcc and MnP production was performed in this work. Ten strains were grown through solid-state fermentation on a medium based on Pinus spp. sawdust, wheat bran and calcium carbonate. High Lcc and MnP activities were found with these strains. Highest Lcc activity, 741 ± 245 U gdm−1 of solid state-cultivation medium, was detected on strain IB11 after 32 days, while the highest MnP activity occurred with strains IB05, IB09, and IB11 (5,333 ± 357; 4,701 ± 652; 5,999 ± 1,078 U gdm−1, respectively). The results obtained here highlight the importance of further experiments with lignocellulolytic enzymes present in different strains of Pleurotus species. Such results also indicate the possibility of selecting more valuable strains for future biotechnological applications, in soil bioremediation and biological biomass pre-treatment in biofuels production, for instance, as well as obtaining value-added products from mushrooms, like phenol oxidase enzymes. PMID:24159307
Tejedor Junco, María Teresa; Gonzalez-Martin, Margarita; Rodriguez Gonzalez, Noe Francisco; Gutierrez, Carlos
This study investigated the presence of Enterococcus spp. strains in camel faeces, their virulence factors, and resistance to the antibiotics commonly used as therapy of enterococcal infections. One hundred and seventy three Enterococcus strains were isolated and identified to species level using polymerase chain reaction (PCR). Susceptibility to 11 antimicrobials was determined by disk diffusion method. Minimal Inhibitory Concentrations (MIC) of penicillin, ampicillin, vancomycin, teicoplanin, gentamicin, and streptomycin were all determined. Genes encoding resistance to vancomycin, tetracycline, and erythromycin as well as genes encoding some virulence factors were identified by PCR. Enterococcus hirae (54.3%) and Enterococcus faecium (25.4%) were the species most frequently isolated. None of the strains were resistant to vancomycin, teicoplanin, ampicillin or showed high level aminoglycoside resistance (HLAR). Strains resistant to rifampicin (42.42%) were those most commonly found followed those resistant to trimethoprim - sulfamethoxazole (33.33%). The genes tetM, tetL, vanC1, and vanC2-C3 were detected in some strains. Virulence genes were not detected. Monitoring the presence of resistant strains of faecal enterococci in animal used with recreational purposes is important to prevent transmission of those strains to humans and to detect resistance or virulence genes that could be transferred to other clinically important bacteria.
Yun, Hyun Sun; Heo, Ju Hee; Son, Seok Jun; Park, Mi Ri; Oh, Sangnam; Song, Min-Ho; Kim, Jong Nam; Go, Gwang-Woong; Cho, Ho-Seong; Choi, Nag-Jin; Jo, Seung-Wha; Jeong, Do-Youn; Kim, Younghoon
We investigated whether Bacillus spp., newly isolated from Korean traditional food resources, influence the resistance of hosts to foodborne pathogens, by using Caenorhabditis elegans as a surrogate host model. Initially, we selected 20 Bacillus spp. that possess antimicrobial activity against various foodborne pathogens, including Staphylococcus aureus. Among the selected strains, six strains of Bacillus spp. used in preconditioning significantly prolonged the survival of nematodes exposed to S. aureus. Based on 16S rRNA gene sequencing, all six strains were identified as B. licheniformis. Our findings suggest that preconditioning with B. licheniformis may modulate the host defense response against S. aureus.
Isolation, Virulence, and Antimicrobial Resistance of Methicillin-Resistant Staphylococcus aureus (MRSA) and Methicillin Sensitive Staphylococcus aureus (MSSA) Strains from Oklahoma Retail Poultry Meats.
Abdalrahman, Lubna S; Stanley, Adriana; Wells, Harrington; Fakhr, Mohamed K
Staphylococcus aureus is one the top five pathogens causing domestically acquired foodborne illness in the U.S. Only a few studies are available related to the prevalence of S. aureus and MRSA in the U.S. retail poultry industry. The objectives of this study were to determine the prevalence of S. aureus (MSSA and MRSA) in retail chicken and turkey meats sold in Tulsa, Oklahoma and to characterize the recovered strains for their antimicrobial resistance and possession of toxin genes. A total of 167 (114 chicken and 53 turkey) retail poultry samples were used in this study. The chicken samples included 61 organic samples while the rest of the poultry samples were conventional. The overall prevalence of S. aureus was 57/106 (53.8%) in the conventional poultry samples and 25/61 (41%) in the organic ones. Prevalence in the turkey samples (64.2%) was higher than in the chicken ones (42.1%). Prevalence of S. aureus did not vary much between conventional (43.4%) and organic chicken samples (41%). Two chicken samples 2/114 (1.8%) were positive for MRSA. PFGE identified the two MRSA isolates as belonging to PFGE type USA300 (from conventional chicken) and USA 500 (from organic chicken) which are community acquired CA-MRSA suggesting a human based source of contamination. MLST and spa typing also supported this conclusion. A total of 168 Staphylococcus aureus isolates (101 chicken isolates and 67 turkey isolates) were screened for their antimicrobial susceptibility against 16 antimicrobials and their possession of 18 different toxin genes. Multidrug resistance was higher in the turkey isolates compared to the chicken ones and the percentage of resistance to most of the antimicrobials tested was also higher among the turkey isolates. The hemolysin hla and hld genes, enterotoxins seg and sei, and leucocidins lukE-lukD were more prevalent in the chicken isolates. The PVL gene lukS-lukF was detected only in chicken isolates including the MRSA ones. In conclusion, S. aureus is
Janek, Daniela; Zipperer, Alexander; Kulik, Andreas; Krismer, Bernhard; Peschel, Andreas
The human nasal microbiota is highly variable and dynamic often enclosing major pathogens such as Staphylococcus aureus. The potential roles of bacteriocins or other mechanisms allowing certain bacterial clones to prevail in this nutrient-poor habitat have hardly been studied. Of 89 nasal Staphylococcus isolates, unexpectedly, the vast majority (84%) was found to produce antimicrobial substances in particular under habitat-specific stress conditions, such as iron limitation or exposure to hydrogen peroxide. Activity spectra were generally narrow but highly variable with activities against certain nasal members of the Actinobacteria, Proteobacteria, Firmicutes, or several groups of bacteria. Staphylococcus species and many other Firmicutes were insusceptible to most of the compounds. A representative bacteriocin was identified as a nukacin-related peptide whose inactivation reduced the capacity of the producer Staphylococcus epidermidis IVK45 to limit growth of other nasal bacteria. Of note, the bacteriocin genes were found on mobile genetic elements exhibiting signs of extensive horizontal gene transfer and rearrangements. Thus, continuously evolving bacteriocins appear to govern bacterial competition in the human nose and specific bacteriocins may become important agents for eradication of notorious opportunistic pathogens from human microbiota. PMID:27490492
The main goal of this study was to determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA), particularly livestock-associated (LA)-MRSA in pigs and pork. Genotypic relatedness of isolates on-farm, at slaughter and retail was assessed. Paired nasal and peri-anal swab samples we...
Grinholc, Mariusz; Szramka, Bozena; Olender, Katarzyna; Graczyk, Alfreda
Photodynamic therapy (PDT) is based on photosensitizers activated by light of appropriate wavelength. Their activation leads to generation of singlet oxygen and free radicals responsible for the cytotoxic effect. The aim of this project was to compare the bactericidal effect of PDT using different porphyrin photosensitizers against a methicillin-resistant Staphylococcus aureus strain. Exogenous sensitizers (protoporphyrin IX and newly synthesized derivative, protoporphyrin diarginate) induced a 3 log10-unit reduction in bacterial viable counts. With the use of endogenous, ALA-induced porphyrins, a 1.6 log10-unit reduction was obtained. The sensitizers tested executed their antibacterial activity with no essential change in the antibiotic resistance pattern of the studied strain.
Drew, W L; Barry, A L; O'Toole, R; Sherris, J C
The resistance of Staphylococcus aureus to methicillin and related drugs can be reliably determined by using the Kirby-Bauer method of susceptibility testing if the incubation temperature is 35 C or below, but resistance may be missed at 37 C. The 1-mug discs of oxacillin and nafcillin or the 5-mug discs of methicillin may be used for this purpose but not the 1-mug discs of cloxacillin. The latter fail to discriminate between sensitive and resistant staphylococci by zone measurement; some resistant strains of staphylococci may show larger zones of inhibition than sensitive strains. Stability of these antibiotic-containing discs was studied under conditions of temperature and humidity variation that might be encountered in a clinical laboratory refrigerator. Oxacillin discs were the most stable and are to be preferred for susceptibility testing. Nafcillin discs were less stable, and methicillin discs lose their potency rapidly unless carefully stored in a refrigerator with a desiccant.
Moubareck, Carole; Meziane-Cherif, Djalal; Courvalin, Patrice; Périchon, Bruno
VanA-type Staphylococcus aureus strain VRSA-7 was partially dependent on glycopeptides for growth. The vanA gene cluster, together with the erm(A) and the ant(9)-Ia resistance genes, was carried by the ca. 35- to 40-kb conjugative plasmid pIP848 present at five copies per cell. The chromosomal ddl gene had a mutation that led to a N308K substitution in the d-Ala:d-Ala ligase that resulted in a 1,000-fold decrease in activity relative to that of strain VRSA-6. Strain VRSA-7 grown in the absence or in the presence of vancomycin mainly synthesized precursors ending in d-Ala-d-Lac, indicating that the strain relied on the vancomycin resistance pathway for peptidoglycan synthesis. Greatly enhanced growth in the presence of glycopeptides and the absence of mutations in the genes for VanR and VanS indicated the inducible expression of resistance. Thus, a combination of loose regulation of the vanA operon by the two-component system and a gene dosage effect accounts for the partial glycopeptide dependence of VRSA-7. Since peptidoglycan precursors ending in d-Ala-d-Lac are not processed by PBP 2′, the strain was fully susceptible to oxacillin, despite the production of a wild-type PBP 2′. PMID:19528271
Zeng, Xuefeng; He, Laping; Guo, Xu; Deng, Li; Yang, Wangen; Zhu, Qiujin; Duan, Zhenhua
This study aimed to determine the predominant processing adaptability of 27 selected isolates of Staphylococcus xylosus in 'Suan yu', a traditional Chinese low-salt fermented whole-fish product. The isolates were screened for proteolytic, lipolytic, and enzymatic profiles; amino-acid decarboxylase content; antimicrobial activities; and tolerance to low temperatures, pH5.0, and salt. Two S. xylosus strains grew at 10°C in the presence of 10% NaCl and at pH5.0. Agar-plate assays and sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed that 21 and 8 of the strains exhibited appropriate proteolytic activities against myofibrillar and sarcoplasmic proteins, respectively. All S. xylosus strains also displayed different enzymatic profiles, and most strains showed negative decarboxylase activities. The results of this step were used as input data for a Principal Component Analysis; therefore, the most technologically relevant strain 3 and 8 were combined with L. plantarum 120 as MS1 and MS2, respectively, were further selected for the fermented fish surimi, and the fish surimi inoculated with mixed starter cultures (MS1, MS2) scored high for overall acceptability. Free amino acid contents of 1757 and 1765mg/100g sample were found in fish surimi inoculated with MS1 and MS2, respectively, after 72h of fermentation. Therefore, Sx-3 and Sx-8, which presented the best predominant processing adaptability, is an eligible starter culture for fermented fish production.
Ozkul, Hilal; Oktem, I M Ali; Gülay, Zeynep
Panton-Valentin leucocidin (PVL) is a cytotoxin which causes tissue necrosis by degradating leucocytes and other cell types. PVL has recently become very up to date as it has been shown to be the major virulance factor of community acquired methicillin resistant Staphylococcus aureus strains. In this study, the presence of PVL was investigated in methicillin sensitive and resistant S. aureus (MSSA and MRSA, respectively) strains which were isolated from clinical samples between January 2005-May 2006 at Dokuz Eylul University Hospital, Izmir. Fifty five MRSA and 79 MSSA strains which were isolated from blood, wound and respiratory tract samples were randomly included to the study. The presence of PVL was evaluated by multiplex polymerase chain reaction (PCR) which detects pvl and S. aureus-specific nuc genes. As a result, PVL positivities were detected in two (5%) of 40 MSSA and four (10.3%) of 39 MSSA strains isolated in the years 2005 and 2006, respectively. None of the MRSA isolates had pvl gene. Although this cytotoxin was rarely detected among MSSA isolates, it was interesting to note that the prevalence of PVL was twice more in the year 2006 compared to 2005. It was also worth to notify that four of six (66.7%) PVL positive strains had been isolated from the patients of general surgery inpatient or outpatient clinics.
Schnellmann, Christina; Gerber, Vinzenz; Rossano, Alexandra; Jaquier, Valentine; Panchaud, Yann; Doherr, Marcus G; Thomann, Andreas; Straub, Reto; Perreten, Vincent
Because of the frequency of multiple antibiotic resistance, Staphylococcus species often represent a challenge in incisional infections of horses undergoing colic surgery. To investigate the evolution of antibiotic resistance patterns before and after preventative peri- and postoperative penicillin treatment, staphylococci were isolated from skin and wound samples at different times during hospitalization. Most staphylococci were normal skin commensals and belonged to the common coagulase-negative group. In some cases they turned out to be opportunistic pathogens present in wound infections. MICs were determined for 12 antibiotics, and antibiotic resistance genes were detected by microarray. At hospital admission, horses harbored staphylococci that were susceptible to antibiotics or resistant to one group of drugs, mainly due to the presence of new variants of the methicillin and macrolide resistance genes mecA and mph(C), respectively. After 3 days, the percentage of Staphylococcus isolates displaying antibiotic resistance, as well as the number of resistance genes per isolate, increased moderately in hospitalized horses without surgery or penicillin treatment but dramatically in hospitalized horses after colic surgery as well as penicillin treatment. Staphylococcus species displaying multiple resistance were found to harbor mainly genes conferring resistance to beta-lactams (mecA and blaZ), aminoglycosides [str and aac(6')-Ie-aph(2')-Ia], and trimethoprim [dfr(A) and dfr(D)]. Additional genes conferring resistance to macrolides [mph(C), erm(C), and erm(B)], tetracycline [tet(K) and tet(M)], chloramphenicol [cat(pC221) and cat(pC223)], and streptothricin (sat4) appeared in several strains. Hospitalization and preventive penicillin use were shown to act as selection agents for multidrug-resistant commensal staphylococcal flora.
Abraham, Nabil M.; Lamlertthon, Supaporn; Fowler, Vance G.
Staphylococcus aureus is a leading cause of catheter infections, and biofilm formation plays a key role in the pathogenesis. Metal ion chelators inhibit bacterial biofilm formation and viability, making them attractive candidates as components in catheter lock solutions. The goal of this study was to characterize further the effect of chelators on biofilm formation. The effect of the calcium chelators ethylene glycol tetraacetic acid (EGTA) and trisodium citrate (TSC) on biofilm formation by 30 S. aureus strains was tested. The response to subinhibitory doses of EGTA and TSC varied dramatically depending on strain variation. In some strains, the chelators prevented biofilm formation, in others they had no effect, and they actually enhanced biofilm formation in others. The molecular basis for this phenotypic variability was investigated using two related strains: Newman, in which biofilm formation was inhibited by chelators, and 10833, which formed strong biofilms in the presence of chelators. It was found that deletion of the gene encoding the surface adhesin clumping factor B (clfB) completely eliminated chelator-induced biofilm formation in strain 10833. The role of ClfB in biofilm formation activity in chelators was confirmed in additional strains. It was concluded that biofilm-forming ability varies strikingly depending on strain background, and that ClfB is involved in biofilm formation in the presence EGTA and citrate. These results suggest that subinhibitory doses of chelating agents in catheter lock solutions may actually augment biofilm formation in certain strains of S. aureus, and emphasize the importance of using these agents appropriately so that inhibitory doses are achieved consistently. PMID:22516131
Navarro, E; Nalin, R; Gauthier, D; Normand, P
The phylogenetic relationships of Frankia strains infective on Gymnostoma with other Frankia strains was analyzed. Partial sequencing of the 16S rDNA and use of specific primers showed that the Frankia strains present in Gymnostoma are phylogenetically close to Elaeagnus-infective strains. This finding was confirmed by using the sequences of the hypervariable nifDK intergenic spacer. The strains present in Gymnostoma nodules were close to one another. Clustered with Elaeagnus-infective strains, and distantly related to Casuarina and Alnus-infective strains. Morphological observations of strains and cross-inoculation trials showed that Gymnostoma-infective strains are indistinguishable from Elaeagnus-infective strains. Results of both phenotypic and genotypic approaches indicate that Gymnostoma-infective strains are Elaeagnus infective and not Casuarina infective. PMID:9097456
Turbidity methods offer possibilities for generating data required for addressing microorganism variability in risk modeling given that the results of these methods correspond to those of viable count methods. The objectives of this study were to identify the best approach for determining growth parameters based on turbidity data and use of a Bioscreen instrument and to characterize variability in growth parameters of 34 Staphylococcus aureus strains of different biotypes isolated from broiler carcasses. Growth parameters were estimated by fitting primary growth models to turbidity growth curves or to detection times of serially diluted cultures either directly or by using an analysis of variance (ANOVA) approach. The maximum specific growth rates in chicken broth at 17 degrees C estimated by time to detection methods were in good agreement with viable count estimates, whereas growth models (exponential and Richards) underestimated growth rates. Time to detection methods were selected for strain characterization. The variation of growth parameters among strains was best described by either the logistic or lognormal distribution, but definitive conclusions require a larger data set. The distribution of the physiological state parameter ranged from 0.01 to 0.92 and was not significantly different from a normal distribution. Strain variability was important, and the coefficient of variation of growth parameters was up to six times larger among strains than within strains. It is suggested to apply a time to detection (ANOVA) approach using turbidity measurements for convenient and accurate estimation of growth parameters. The results emphasize the need to consider implications of strain variability for predictive modeling and risk assessment.
Mandal, Santi M; Ghosh, Ananta K; Pati, Bikas R
Vancomycin-resistant Staphylococcus aureus (VRSA) and methicillin-resistant S aureus (MRSA) strains were examined in hospital effluents. Most S aureus strains are resistant to methicillin (MRSA), followed by tetracycline. Approximately 15% of MRSA strains are also resistant to vancomycin (VRSA). All VRSA strains developed a VanR/VanS-regulated 2-component system of VanA-type resistance in their genome. Results indicate that there is a possibility of developing resistance to aminoglycosides by VRSA strains in the near future.
Sarria-Guzmán, Yohanna; López-Ramírez, María Patricia; Chávez-Romero, Yosef; Ruiz-Romero, Erick; Dendooven, Luc; Bello-López, Juan Manuel
Forty-six Aeromonas spp. strains were isolated from fresh fish and investigated for their antimicrobial susceptibility, detection of Class 1 integrons by PCR, and arrangement of gene cassettes. Selected isolates were further characterized by enterobacterial repetitive intergenic consensus-PCR. Twenty isolates were found to carry Class 1 integrons. Amplification of the variable regions of the integrons revealed diverse bands ranging in size from 150 to 1,958 pb. Sequence analysis of the variable regions revealed the presence of several gene cassettes, such as adenylyl transferases (aadA2 and aadA5), dihydrofolate reductases (dfrA17 and dfrA1), chloramphenicol acetyl transferase (catB3), β-lactamase (oxa2), lincosamide nucleotidil transferase (linF), aminoglycoside-modifying enzyme (apha15), and oxacillinase (bla OXA-10). Two open reading frames with an unknown function were identified as orfC and orfD. The aadA2 cassette was the most common integron found in this study. Interestingly, five integrons were detected in the plasmids that might be involved in the transfer of resistance genes to other bacteria. This is a first report of cassette encoding for lincosamides (linF) resistance in Aeromonas spp. Implications on the incidence of integrons in isolates of Aeromonas spp. from fresh fish for human consumption, and its possible consequences to human health are discussed.
Liu, Xiaoyu; Zhang, Shijie
Increasing cases of infections caused by methicillin-resistant Staphylococcus aureus (MRSA) strains in healthy individuals have raised concerns worldwide. MRSA strains are resistant to almost the entire family of β-lactam antibiotics due to the acquisition of an extra penicillin-binding protein, PBP2a. Studies have shown that spoVG is involved in oxacillin resistance, while the regulatory mechanism remains elusive. In this study, we have found that SpoVG plays a positive role in oxacillin resistance through promoting cell wall synthesis and inhibiting cell wall degradation in MRSA strain N315. Deletion of spoVG in strain N315 led to a significant decrease in oxacillin resistance and a dramatic increase in Triton X-100-induced autolytic activity simultaneously. Real-time quantitative reverse transcription-PCR revealed that the expression of 8 genes related to cell wall metabolism or oxacillin resistance was altered in the spoVG mutant. Electrophoretic mobility shift assay indicated that SpoVG can directly bind to the putative promoter regions of lytN (murein hydrolase), femA, and lytSR (the two-component system). These findings suggest a molecular mechanism in which SpoVG modulates oxacillin resistance by regulating cell wall metabolism in MRSA. PMID:27001809
Lührmann, Anne; Matthes, Rutger; Kramer, Axel
Aim: The antimicrobial activity of cold atmospheric pressure plasma (CAP), also called tissue tolerable plasma (TTP), could be a promising option to eradicate methicillin-sensitive as well as methicillin-resistant Staphylococcus aureus strains, which often colonize chronic wounds. Currently, the influence of CAP on the susceptibility of S. aureus to antibiotics is scarcely known, but could be important for treatment of wounds. Therefore, the aim of this study was to investigate whether CAP has an impact on the susceptibility of different S. aureus strains to different antibiotics. Method: For assessment, the agar diffusion test with different antibiotic test disks (cefuroxime, gentamicin, oxacillin, vancomycin, ciprofloxacin, co-trimoxazole, clindamycin, erythromycin) was used. Test strains were spread on agar plates and CAP treated before the antibiotic disks were placed. After 24 hours cultivation, the inhibited growth zones were measured and differences statistically evaluated. Results: In most cases, CAP had a negligible influence on the susceptibility to antibiotics. For two strains, the susceptibility significantly decreased to β-lactam antibiotics. Conclusion: Because CAP can influence the antibiotic susceptibility of S. aureus, before conducting combined treatment with local plasma application on wounds and systemic antibiotics, their interaction must be analysed in vitro to exclude unwanted combination effects. PMID:27610332
Haroun, Mohammad F; Al-Kayali, Rawaa S
Objective(s): To evaluate the in vitro interaction between different extracts of Thymbra spicata L. and certain antimicrobial drugs of different mechanisms, including ampicillin, cefotaxime, amikacin and ciprofloxacin. This study was performed against multidrug-resistant strains of Staphylococcus aureus and Klebsiella pneumoniae. Materials and Methods: Evaluation of antibacterial activity and synergy interaction between plant extracts and antimicrobial agents was carried out using checkerboard microdilution. Results: Different interactions (synergistic, additive and indifference) were observed between plant crude extracts and used antibiotics depending on the strain. The fractional inhibitory concentration (FIC) index ranged from 0.02 to 1.5 for S. aureus and 0.25 to 2 for K. pneumoniae strains. The best synergistic capacity appeared with cefotaxime against S. aureus strains, where the activity of cefotaxime was increased from 8- to 128-fold. Conclusion: These results may indicate that T. spicata extracts potentiates the antimicrobial action of antibiotics, suggesting a possible utilization of this herb in combination therapy against emerging multidrug-resistance S. aureus and K. pneumoniae. PMID:27917275
Ostojić, Maja; Hukić, Mirsada
Staphylococcus aureus is a major cause of hospital-acquired infections worldwide. Increased frequency of methicillin-resistant Staphylococcus aureus (MRSA) in hospitalized patients and possibility of vancomycin resistance requires rapid and reliable characterization of isolates and control of MRSA spread in hospitals. Typing of isolates helps to understand the route of a hospital pathogen spread. The aim of this study was to investigate and compare genotypic and phenotypic characteristics of MRSA samples on three different geography locations. In addition, our aim was to evaluate three different methods of MRSA typing: spa-typing, agr-typing and GenoType MRSA. We included 104 samples of MRSA, isolated in 3 different geographical locations in clinical hospitals in Zagreb, Mostar, and Heidelberg, during the period of six months. Genotyping and phenotyping were done by spa-typing, agr-typing and dipstick assay GenoType MRSA. We failed to type all our samples by spa-typing. The most common spa-type in clinical hospital Zagreb was t041, in Mostar t001, and in Heidelberg t003. We analyzed 102/104 of our samples by agr-typing method. We did not find any agr-type IV in our locations. We analyzed all our samples by the dipstick assay GenoType MRSA. All isolates in our study were MRSA strains. In Zagreb there were no positive strains to PVL gene. In Mostar we have found 5/25 positive strains to PVL gene, in Heidelberg there was 1/49. PVL positive isolates were associated with spa-type t008 and agr-type I, thus, genetically, they were community-associated MRSA (CA-MRSA). Dipstick assay GenoType MRSA has demonstrated sufficient specificity, sensibility, simple performance and low cost, so we could introduce it to work in smaller laboratories. Using this method may expedite MRSA screening, thus preventing its spread in hospitals. PMID:26295294
Ostojić, Maja; Hukić, Mirsada
Staphylococcus aureus is a major cause of hospital-acquired infections worldwide. Increased frequency of methicillin-resistant Staphylococcus aureus (MRSA) in hospitalized patients and possibility of vancomycin resistance requires rapid and reliable characterization of isolates and control of MRSA spread in hospitals. Typing of isolates helps to understand the route of a hospital pathogen spread. The aim of this study was to investigate and compare genotypic and phenotypic characteristics of MRSA samples on three different geography locations. In addition, our aim was to evaluate three different methods of MRSA typing: spa-typing, agr-typing and GenoType MRSA. We included 104 samples of MRSA, isolated in 3 different geographical locations in clinical hospitals in Zagreb, Mostar, and Heidelberg, during the period of six months. Genotyping and phenotyping were done by spa-typing, agr-typing and dipstick assay GenoType MRSA. We failed to type all our samples by spa-typing. The most common spa-type in clinical hospital Zagreb was t041, in Mostar t001, and in Heidelberg t003.We analyzed 102/104 of our samples by agr-typing method. We did not find any agr-type IV in our locations. We analyzed all our samples by the dipstick assay GenoType MRSA. All isolates in our study were MRSA strains. In Zagreb there were no positive strains to PVL gene. In Mostar we have found 5/25 positive strains to PVL gene, in Heidelberg there was 1/49. PVL positive isolates were associated with spa-type t008 and agr-type I, thus, genetically, they were community-associated MRSA (CA-MRSA). Dipstick assay GenoType MRSA has demonstrated sufficient specificity, sensibility, simple performance and low cost, so we could introduce it to work in smaller laboratories. Using this method may expedite MRSA screening, thus preventing its spread in hospitals.
Garita-Cambronero, Jerson; Palacio-Bielsa, Ana; López, María M; Cubero, Jaime
Xanthomonas arboricola is a species in genus Xanthomonas which is mainly comprised of plant pathogens. Among the members of this taxon, X. arboricola pv. pruni, the causal agent of bacterial spot disease of stone fruits and almond, is distributed worldwide although it is considered a quarantine pathogen in the European Union. Herein, we report the draft genome sequence, the classification, the annotation and the sequence analyses of a virulent strain, IVIA 2626.1, and an avirulent strain, CITA 44, of X. arboricola associated with Prunus spp. The draft genome sequence of IVIA 2626.1 consists of 5,027,671 bp, 4,720 protein coding genes and 50 RNA encoding genes. The draft genome sequence of strain CITA 44 consists of 4,760,482 bp, 4,250 protein coding genes and 56 RNA coding genes. Initial comparative analyses reveals differences in the presence of structural and regulatory components of the type IV pilus, the type III secretion system, the type III effectors as well as variations in the number of the type IV secretion systems. The genome sequence data for these strains will facilitate the development of molecular diagnostics protocols that differentiate virulent and avirulent strains. In addition, comparative genome analysis will provide insights into the plant-pathogen interaction during the bacterial spot disease process.
Henson, Michael W.; Santo Domingo, Jorge W.; Kourtev, Peter S.; Jensen, Roderick V.; Dunn, James A.
Hexavalent chromium [Cr(VI)] is a soluble carcinogen that has caused widespread contamination of soil and water in many industrial nations. Bacteria have the potential to aid remediation as certain strains can catalyze the reduction of Cr(VI) to insoluble and less toxic Cr(III). Here, we examine Cr(VI) reducing Microbacterium spp. (Cr-K1W, Cr-K20, Cr-K29, and Cr-K32) isolated from contaminated sediment (Seymore, Indiana) and show varying chromate responses despite the isolates’ phylogenetic similarity (i.e., identical 16S rRNA gene sequences). Detailed analysis identified differences based on genomic metabolic potential, growth and general metabolic capabilities, and capacity to resist and reduce Cr(VI). Taken together, the discrepancies between the isolates demonstrate the complexity inter-strain variation can have on microbial physiology and related biogeochemical processes. PMID:26587353
Li, Qiuchun; Xie, Xiaolei; Yin, Kequan; Tang, Yueyuan; Zhou, Xiaohui; Chen, Yun; Xia, Jie; Hu, Yachen; Ingmer, Hanne; Li, Yang; Jiao, Xinan
Staphylococcus epidermidis is considered as a major cause of nosocomial infections, bringing an immense burden to healthcare systems. Virulent phages have been confirmed to be efficient in combating the pathogen, but the prensence of CRISPR-Cas system, which is a bacterial immune system eliminating phages was reported in few S. epidermidis strains. In this study, the CRISPR-Cas system was detected in 12 from almost 300 published genomes in GenBank and by PCR of cas6 gene in 18 strains out of 130 clinical isolates obtained in Copenhagen. Four strains isolated in 1965-1966 harboured CRISPR elements confirming that this immunity system was not recently acquired by S. epidermidis. In these CRISPR-positive strains, 44 and 12 spacers were found to belong to CRISPR1 and CRISPR2 elements, respectively. However, only 15 spacers displayed homology to reported phages and plasmids DNA. Interestingly, 5 different spacers located in the CRISPR1 locus with homolgy to virulent phage 6ec DNA sequences, and 19 strains each carrying 2 or 3 different spacers recognizing this phage, implied that the CRISPR-Cas immunity could be abrogated by nucleotide mismatch between the spacer and its target phage sequence, while new spacers obtained from the evolved phage could recover the CRISPR interference. In addition, phylogenetic analysis of the 29 CRISPR-positive isolates divided them into four lineages, with 81% human blood isolates as a distinct sub-lineage, suggesting that the CRISPR difference is closely related to diverse habitats. Knowledge of CRISPR and its prevalence may ultimately be applied in the understanding of origin and evolution of CRISPR-positive S. epidermidis strains.
Chaves-Moreno, Diego; Wos-Oxley, Melissa L.; Jáuregui, Ruy; Medina, Eva
Understanding the behaviour of opportunistic pathogens such as Staphylococcus aureus in their natural human niche holds great medical interest. With the development of sensitive molecular methods and deep-sequencing technology, it is now possible to robustly assess the global transcriptome of bacterial species in their human habitat. However, as the genomes of the colonizing strains are often not available compiling the pan-genome for the species of interest may provide an effective method to reliably and rapidly compile the transcriptome of a bacterial species. The pan-genome of S. aureus and its associated core and accessory components were compiled based on 25 genomes and comprises a total of 65,557 proteins clustering into 4,198 Orthologous Groups (OGs). The generated gene catalogue was used to assign RNAseq-derived sequence reads to S. aureus in a variety of in vitro and in vivo samples. In all cases, the number of reads that could be assigned to S. aureus was greater using the OG database than using a reference genome. Growth of two S. aureus strains in synthetic nasal medium confirmed that both strains experienced strong iron starvation. Traits such as purine metabolism appeared to be more affected in a typical nasal colonizer than in a strain representative of the S. aureus USA300 lineage. Mapping sequencing reads from a metatranscriptome generated from the human anterior nares allowed the identification of genes highly expressed by S. aureus in vivo. The OG database generated in this study represents a useful tool to obtain a snapshot of the functional attributes of S. aureus under different in vitro and in vivo conditions. The approach proved to be advantageous to assign sequencing reads to bacterial strains when RNAseq data is derived from samples where strain information and/or the corresponding genome/s are unavailable. PMID:26717500
Grover, Minakshi; Madhubala, R; Ali, Sk Z; Yadav, S K; Venkateswarlu, B
Microorganisms isolated from stressed ecosystem may prove as ideal candidates for development of bio-inoculants for stressed agricultural production systems. In the present study, moisture stress tolerant rhizobacteria were isolated from the rhizosphere of sorghum, pigeonpea, and cowpea grown under semiarid conditions in India. Four isolates KB122, KB129, KB133, and KB142 from sorghum rhizosphere exhibited plant growth promoting traits and tolerance to salinity, high temperature, and moisture stress. These isolates were identified as Bacillus spp. by 16S rDNA sequence analysis. The strains were evaluated for growth promotion of sorghum seedlings under two different moisture stress conditions (set-I, continuous 50% soil water holding capacity (WHC) throughout the experiment and set-II, 75% soil WHC for 27 days followed by no irrigation for 5 days) under greenhouse conditions. Plate count and scanning electron microscope studies indicated successful root surface colonization by inoculated bacteria. Plants inoculated with Bacillus spp. strains showed better growth in terms of shoot length and root biomass with dark greenish leaves due to high chlorophyll content while un-inoculated plants showed rolling of the leaves, stunted appearance, and wilting under both stress conditions. Inoculation also improved leaf relative water content and soil moisture content. However, variation in proline and sugar content in the different treatments under two stress conditions indicated differential effect of microbial treatments on plant physiological parameters under stress conditions.
Lara-Herrera, I; Mata, G; Gaitán-Hernández, R
The effect of the cryopreservation of six Pleurotus strains was evaluated. Primordia initiation, number of flushes, biological efficiency and fruiting body size obtained with respect to pileus diameter was recorded. These strains were previously evaluated before storage in liquid nitrogen. Variation in the number of flushes (3-4), the fruiting body size (< 5 cm at > 15 cm) and biological efficiency was observed. This varied according to the strain used, ranging from 55-105.6%. The fruiting bodies of the cryopreserved strains did not differ with respect to the untreated strains.
Prevalence and risk factors of early fecal carriage of Enterococcus faecalis and Staphylococcus spp and their antimicrobial resistant patterns among healthy neonates born in a hospital setting in central Saudi Arabia
El-Kersh, Talat A.; Marie, Mohammed A.; Al-Sheikh, Yazeed A.; Al-Agamy, Mohamed H.; Al-Bloushy, Ahmad A.
Objectives: To investigate the prevalence, antibiotic resistant profiles, and risk factors of early fecal carriage of Enterococcus faecalis (E. faecalis) and staphylococci among 150 healthy Saudi neonates born in a hospital setting in central Saudi Arabia. Methods: This prospective study was conducted in Al-Bukayriyah General Hospital, Qassim, Saudi Arabia, between June 2012 and January 2013. The E. faecalis and Staphylococcus spp. isolates were identified manually, and Vitek2 system was used for identity confirmation at the species level and minimum inhibitory concentration-susceptibility testing. Results: Enterococcus faecalis (n=73) and Staphylococcus spp. (n=18) were recovered. Unlike staphylococci, E. faecalis colonization did not significantly vary from day one up to 7 days of life, regardless of the type of feeding, but it was relatively higher among vaginally versus cesarean delivery. Both Staphylococcus epidermidis (S. epidermidis) and Staphylococcus aureus carriage increase as the body weight increases, and this difference was significant (p=0.025) for S. epidermidis. High-level resistance in Gentamycin among E. faecalis isolates was 25% and 11% to Streptomycin. Thirty percent of S. epidermidis were resistant to oxacillin and exhibited multidrug-resistant (MDR) patterns of 5 resistant markers, which were also observed among 2/5 (40%) of Methicillin-resistant Staphylococcus aureus isolates. Conclusion: Enterococcus faecalis did not significantly vary in relation to type of delivery, age up to 7 days, and type of feeding. The neonatal fecal carriage of MDR isolates should be considered as a crucial reservoir to the further spread of antimicrobial resistance genes among hospitals, cross infections, and the community. PMID:26905350
Sidashenko, O I; Voronkova, O S; Sirokvasha, O A; Vinnikov, A I
A comparative study of the manifestation of pathogenicity factors: hemolytic, lipase, letsytinase activity and ability to adhere in 20 film-forming and 17 non-film-forming strains of S. epidermidis. Studying pathogenicity factors of the film-forming strains it was found that complete hemolysis and lipase activity shown was by all the film-forming strains of S. epidermidis, letsytinase activity was observed in 80%. Among the non-film-forming strains complete hemolysis and lipase activity were observed in 89% and letsytinase - 71%. Researched non-film-forming and film-forming strains of S. epidermidis showed the ability to adhere to buccal epithelial cells of humans. Found that all the film-forming strains of S. epidermidis were hight level adgesion, the highest IAM was equal to 11,84. It was found that among non-film-forming strains of S. epidermidis were low-, medium- and hight level adgesion. IAM of non-film-forming strains of S. epidermidis is 3 times lower compared to the IAM of the film-forming strains of human epithelial cells and was 3.2.
Katsikogianni, M; Spiliopoulou, I; Dowling, D P; Missirlis, Y F
Staphylococcus epidermidis has emerged as a pathogen associated with infections of implanted medical devices. Bacterial adhesion is a crucial step in infection on biomaterial surfaces. To quantitatively determine the relationship between poly (vinyl chloride) (PVC) surface properties and bacterial adhesion, we have compared attachment of slime-producing S. epidermidis strains on PVC and various coatings under flow conditions. Bacterial adhesion and colonization was quantified by counting the viable organisms on the adherent surface as well as by scanning electron microscopy, epifluorescence microscopy and atomic force microscopy. Fluorination of the PVC surface encourages S. epidermidis adhesion whereas; diamond-like carbon (DLC) and especially silver (Ag) coatings seem to inhibit its adhesion. In most materials, the number of adherent bacteria decreased with the increase of shear rate. These results indicate that bacterial adhesion is influenced by the chemical properties of the polymeric surfaces, the surface roughness and the associated flow conditions.
Miranda, J M; Vázquez, B I; Fente, C A; Calo-Mata, P; Cepeda, A; Franco, C M
The presence of Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes was determined in 55 samples of organic poultry meat and in 61 samples of conventional poultry meat. A total of 220 E. coli, 192 S. aureus, and 71 L. monocytogenes strains were analyzed by an agar disk diffusion assay for their resistance to ampicillin, cephalothin, chloramphenicol, ciprofloxacin, doxycycline, fosfomycin, gentamicin, nitrofurantoin, streptomycin, and sulfisoxazole (E. coli); chloramphenicol, ciprofloxacin, clindamycin, doxycycline, erythromycin, gentamicin, nitrofurantoin, oxacillin, and sulfisoxazole (S. aureus); and chloramphenicol, doxycycline, erythromycin, gentamicin, sulfisoxazole, and vancomycin (L. monocytogenes). The results indicated a significantly higher (P < 0.0001) prevalence of E. coli but not of S. aureus and L. monocytogenes in organic poultry meat as compared with conventional poultry meat. E. coli isolated from organic poultry meat exhibited lower levels of antimicrobial resistance against 7 of the 10 antimicrobials tested as compared with isolates recovered from conventional meat. In the case of S. aureus and L. monocytogenes isolated from conventional poultry, antimicrobial resistance was significantly higher only for doxycycline as compared with strains isolated from organic poultry. In the case of E. coli, the presence of multiresistant strains was significantly higher (P < 0.0001) in conventional poultry meat as compared with organic poultry meat. Organically farmed poultry samples showed significantly lower development of antimicrobial resistance in intestinal bacteria such as E. coli.
Calà, Cinzia; Amodio, Emanuele; Di Carlo, Enza; Virruso, Roberta; Fasciana, Teresa; Giammanco, Anna
A major virulence factor of Staphylococcus epidermidis is its ability to form biofilms, permitting it to adhere to a surface and, in turn, to form a mucoid layer on polymer surfaces. Multiple factors have been found to influence bacterial attachment. Currently, this bacterium is commonly associated with hospital infections as a consequence of its ability to colonize, albeit accidentally, medical devices. This study investigated the genetic and phenotypic formation of biofilm in 105 S. epidermidis strains isolated from the skin of hospitalized patients. Fifty-eight of these patients were positive for the mecA gene (MRSE) and 47 were found to be negative (MSSE). Genetic characterizations were performed for the detection of the mecA, icaADBC, atlE, aap, bhp, IS256 and agr groups by PCR. Biofilm production was examined by culturing the strains in TBS medium and TBS with 0.5 and 1% respectively of glucose, and a semiquantitative assay on tissue culture plates was used. Although a molecular analysis estimate of detailed biofilm formation is costly in terms of time and complexity, a semiquantitative assay can be proposed as a rapid and cheap diagnostic method for initial screening to discover virulent strains. We confirmed a close correlation between genetic and phenotypic characteristics, highlighting the fact that, when S. epidermidis isolates were cultured in TSB with 1% of glucose, an increase in biofilm production was observed, as confirmed by positivity for the ica locus by molecular analysis.
Hata, Eiji; Katsuda, Ken; Kobayashi, Hideki; Uchida, Ikuo; Tanaka, Kiyoshi; Eguchi, Masashi
In genetic analysis of bovine Staphylococcus aureus isolates that are recognized as an important pathogenic bacterium in bovine mastitis, multilocus sequence typing (MLST) showed strong correlation to the results of pulsed-field gel electrophoresis, coa PCR-restriction fragment length polymorphism (RFLP), spa typing, and the coagulase serotyping method. According to MLST results, strains derived from sequence type 97 (ST97) and ST705 were suggested as not only dominant bovine S. aureus lineages in Japan but also pandemic bovine S. aureus lineages. Although both lineages seem to be distantly related to each other by phylogenetic analysis, both had common characteristics, i.e., lukM/lukF′-PV and coagulase serotype VI. These characteristics were very rare among minor bovine strains and human strains and may contribute to the host specificity of these lineages. Four methicillin-resistant S. aureus (MRSA) isolates were first confirmed from bovine milk in Japan; these isolates showed geno- and serotypes that were identical or similar to those of human MRSA isolates in Japan (ST5, staphylococcal cassette chromosome mec type II [SCCmec II], Spa type t002 or t375, and coagulase serotype II, and ST89, SCCmec IIIa, Spa type t5266, and coagulase serotype I). ST5 and ST89 are uncommon among bovine isolates in the world, whereas these STs are common among human MRSA isolates in Japan. PMID:20392913
Siljamäki, Pia; Varmanen, Pekka; Kankainen, Matti; Pyörälä, Satu; Karonen, Taru; Iivanainen, Antti; Auvinen, Petri; Paulin, Lars; Laine, Pia K; Taponen, Suvi; Simojoki, Heli; Sukura, Antti; Nyman, Tuula A; Savijoki, Kirsi
The present study reports a comparative proteome cataloging of a bovine mastitis and a human-associated Staphylococcus epidermidis strain with a specific focus on surfome (cell-wall bound and extracellular) proteins. Protein identification by 1DE coupled with LC-MS/MS analyses resulted in 1400 and 1287 proteins from the bovine (PM221) and human (ATCC12228) strains, respectively, covering over 50% of all predicted and more than 30% of all predicted surfome proteins in both strains. Comparison of the identification results suggests elevated levels of proteins involved in adherence, biofilm formation, signal transduction, house-keeping functions, and immune evasion in PM221, whereas ATCC12228 was more effective in expressing host defense evasion proteases, skin adaptation lipases, hemagglutination, and heavy-metal resistance proteins. Phenotypic analyses showed that only PM221 displays protein- and DNA-mediated adherent growth, and that PM221 was more efficient in cleaving tributyrin, a natural compound of milk fat under low CO2 conditions. These findings are in line with the identification data and suggest that distinct expression of lipases and adhesive surfome proteins could lead to the observed phenotypes. This study is the first extensive survey of S. epidermidis proteomes to date, providing several protein candidates to be examined for their roles in adaptation and virulence in vivo. All MS data have been deposited in the ProteomeXchange with identifier PXD000404 (http://proteomecentral.proteomexchange.org/dataset/PXD000404).
Merghni, Abderrahmen; Ben Nejma, Mouna; Dallel, Ines; Tobji, Samir; Ben Amor, Adel; Janel, Sébastien; Lafont, Frank; Aouni, Mahjoub; Mastouri, Maha
Orthodontic and other oral appliances act as reservoir of opportunistic pathogens that can easily become resistant to antibiotics and cause systemic infections. The aim of this study was to investigate the ability of Staphylococcus aureus strains isolated from healthy patients with orthodontic appliances, to adhere to biotic (HeLa cells) and abiotic surfaces (polystyrene and dental alloy). Adhesive ability to polystyrene was tested by crystal violet staining and quantitative biofilm production on dental alloy surfaces was evaluated by MTT reduction assay. In addition, the presence of icaA and icaD genes was achieved by polymerase chain reaction (PCR). Qualitative biofilm production revealed that 70.6% of strains were slime producers. The metabolic activity of S. aureus biofilms on dental alloy surfaces was high and did not differ between tested strains. Moreover, all the isolates were adhesive to HeLa cells and 94% of them harbor icaA and icaD genes. Considerable adhesion and internalization capacity to the epithelial HeLa cells and strong biofilm production abilities together, with a high genotypic expression of icaA/icaD genes are an important equipment of S. aureus to colonize orthodontic appliances and eventually to disseminate towards other body areas.
Salehzadeh, Ali; Zamani, Hojjatolah; Langeroudi, Maedeh Keshtkar; Mirzaie, Amir
Objective(s): Staphylococcus aureus is an important bacterial pathogen responsible for a variety numbers of nosocomial and community acquired infections. Biofilm formation is regarded as an important factor in the establishment of S. aureus infection. The contribution of the genetic background of S. aureus to biofilm formation is poorly understood. The aim of the present work was to genotype S. aureus strains associated to biofilm based on the coagulase and protein A genes and to evaluate the association between the genetic background and the biofilm forming ability of clinical S. aureus isolates. Materials and Methods: A total number of 100 S. aureus were isolated from nosocomial infections and biofilm formation capability was investigated using phenotypic assay and molecular detection of biofilm associated genes. The strains were genotyped based on coagulase (coa) and protein A (spa) gene polymorphisms using restriction fragments length polymorphism-polymerase chain reaction (RFLP-PCR). Results: RFLP-PCR of coa gene generated two types and three subtypes. Amplification of spa gene resulted in two banding patterns and their restriction digestion generated three subtypes. The combined coa and spa RFLP patterns generated nine genotypes (G1-G9). The genotypes G4 and G1 were the most prevalent (32.1% and 24.3%, respectively). Conclusion: High clonal diversity of S. aureus strains able to produce biofilm was observed. Biofilm formation correlates with the spa and coa clonal lineage in our population and testing for multiple gene polymorphisms could be employed for local epidemiologic purposes. PMID:28096965
[The biological kinetics of biofilms of clinical strains of Staphylococcus aureus and Pseudomonas aeruginosa separated from patients with bronchopulmonary complications under traumatic disease of spinal cord].
Ul'ianov, V Iu; Opredelentseva, S V; Shvidenko, I G; Norkin, I A; Korshunov, G V; Gladkova, E V
The capacity and intensity of formation of microbial biofilms was analyzed in 24 strains of Staphylococcus aureus and Pseudomonas aeruginosa in static conditions of cultivation during 24, 48, 72 and 96 yours. The microorganisms were separated from patients with bronchopulmonary infectious complications in acute and early periods of traumatic disease of spinal cord.
Cellier, Gilles; Moreau, Aurélie; Chabirand, Aude; Hostachy, Bruno; Ailloud, Florent; Prior, Philippe
Banana wilt outbreaks that are attributable to Moko disease-causing strains of the pathogen Ralstonia solanacearum (Rs) remain a social and economic burden for both multinational corporations and subsistence farmers. All known Moko strains belong to the phylotype II lineage, which has been previously recognized for its broad genetic basis. Moko strains are paraphyletic and are distributed among seven related but distinct phylogenetic clusters (sequevars) that are potentially major threats to Musaceae, Solanaceae, and ornamental crops in many countries. Although clustered within the Moko IIB-4 sequevar, strains of the epidemiologically variant IIB-4NPB do not cause wilt on Cavendish or plantain bananas; instead, they establish a latent infection in the vascular tissues of plantains and demonstrate an expanded host range and high aggressiveness toward Solanaceae and Cucurbitaceae. Although most molecular diagnostic methods focus on strains that wilt Solanaceae (particularly potato), no relevant protocol has been described that universally detects strains of the Musaceae-infecting Rs phylotype II. Thus, a duplex PCR assay targeting Moko and IIB-4NPB variant strains was developed, and its performance was assessed using an extensive collection of 111 strains representing the known diversity of Rs Moko-related strains and IIB-4NPB variant strains along with certain related strains and families. The proposed diagnostic protocol demonstrated both high accuracy (inclusivity and exclusivity) and high repeatability, detected targets on either pure culture or spiked plant extracts. Although they did not belong to the Moko clusters described at the time of the study, recently discovered banana-infecting strains from Brazil were also detected. According to our comprehensive evaluation, this duplex PCR assay appears suitable for both research and diagnostic laboratories and provides reliable detection of phylotype II Rs strains that infect Musaceae.
Cellier, Gilles; Moreau, Aurélie; Chabirand, Aude; Hostachy, Bruno; Ailloud, Florent; Prior, Philippe
Banana wilt outbreaks that are attributable to Moko disease-causing strains of the pathogen Ralstonia solanacearum (Rs) remain a social and economic burden for both multinational corporations and subsistence farmers. All known Moko strains belong to the phylotype II lineage, which has been previously recognized for its broad genetic basis. Moko strains are paraphyletic and are distributed among seven related but distinct phylogenetic clusters (sequevars) that are potentially major threats to Musaceae, Solanaceae, and ornamental crops in many countries. Although clustered within the Moko IIB-4 sequevar, strains of the epidemiologically variant IIB-4NPB do not cause wilt on Cavendish or plantain bananas; instead, they establish a latent infection in the vascular tissues of plantains and demonstrate an expanded host range and high aggressiveness toward Solanaceae and Cucurbitaceae. Although most molecular diagnostic methods focus on strains that wilt Solanaceae (particularly potato), no relevant protocol has been described that universally detects strains of the Musaceae-infecting Rs phylotype II. Thus, a duplex PCR assay targeting Moko and IIB-4NPB variant strains was developed, and its performance was assessed using an extensive collection of 111 strains representing the known diversity of Rs Moko-related strains and IIB-4NPB variant strains along with certain related strains and families. The proposed diagnostic protocol demonstrated both high accuracy (inclusivity and exclusivity) and high repeatability, detected targets on either pure culture or spiked plant extracts. Although they did not belong to the Moko clusters described at the time of the study, recently discovered banana-infecting strains from Brazil were also detected. According to our comprehensive evaluation, this duplex PCR assay appears suitable for both research and diagnostic laboratories and provides reliable detection of phylotype II Rs strains that infect Musaceae. PMID:25811378
Acevedo, H F; Koide, S S; Slifkin, M; Maruo, T; Campbell-Acevedo, E A
The presence of choriogonadotropin- and alpha-subunit-like materials in two species of bacteria identified as Staphylococcus simulans and Streptococcus faecalis have been demonstrated by the indirect fluorescein-labeled and the indirect peroxidase-labeled immunocytochemical techniques, utilizing antiserum for human choriogonadotropin, for its alpha and beta-subunits and the bera-subunit COOH-terminal peptide. The bacteria were originally isolated from the urine of two patients with advanced forms of cancer. Chromatography done on the water-soluble extract of acetone powder preparations of the bacterial cultures revealed the presence of a material similar to the complete trophoblastic hormone and to its beta-subunit in the culture media of S. simulans, and to the beta-subunit in the media of S. faecalis. No free alpha-subunit was detectable. Furthermore, the choriogonadotropin-like factor demonstrated biological activity in in vivo assay systems. From the present results, it can be concluded that some species of "cancer-associated" bacteria can synthesize a human trophoblastic hormone-like glycoprotein with physicochemical properties similar to those of the human trophoblastic hormone that is biologically active and that is either released complete or as one of its subunits in the culture media. Images PMID:6783540
Bragin, E Yu; Shtratnikova, V Yu; Dovbnya, D V; Schelkunov, M I; Pekov, Yu A; Malakho, S G; Egorova, O V; Ivashina, T V; Sokolov, S L; Ashapkin, V V; Donova, M V
A comparative genome analysis of Mycobacterium spp. VKM Ac-1815D, 1816D and 1817D strains used for efficient production of key steroid intermediates (androst-4-ene-3,17-dione, AD, androsta-1,4-diene-3,17-dione, ADD, 9α-hydroxy androst-4-ene-3,17-dione, 9-OH-AD) from phytosterol has been carried out by deep sequencing. The assembled contig sequences were analyzed for the presence putative genes of steroid catabolism pathways. Since 3-ketosteroid-9α-hydroxylases (KSH) and 3-ketosteroid-Δ(1)-dehydrogenase (Δ(1) KSTD) play key role in steroid core oxidation, special attention was paid to the genes encoding these enzymes. At least three genes of Δ(1) KSTD (kstD), five genes of KSH subunit A (kshA), and one gene of KSH subunit B of 3-ketosteroid-9α-hydroxylases (kshB) have been found in Mycobacterium sp. VKM Ac-1817D. Strains of Mycobacterium spp. VKM Ac-1815D and 1816D were found to possess at least one kstD, one kshB and two kshA genes. The assembled genome sequence of Mycobacterium sp. VKM Ac-1817D differs from those of 1815D and 1816D strains, whereas these last two are nearly identical, differing by 13 single nucleotide substitutions (SNPs). One of these SNPs is located in the coding region of a kstD gene and corresponds to an amino acid substitution Lys (135) in 1816D for Ser (135) in 1815D. The findings may be useful for targeted genetic engineering of the biocatalysts for biotechnological application.
Cázares-García, Saila Viridiana; Arredondo-Santoyo, Marina; Vázquez-Marrufo, Gerardo; Soledad Vázquez-Garcidueñas, Ma; Robinson-Fuentes, Virginia A; Gómez-Reyes, Víctor Manuel
Using the ITS region and the gene tef1, 23 strains of the genus Trichoderma were identified as belonging to the species T. harzianum (n = 14), T. olivascens (n = 1), T. trixiae (n = 1), T. viridialbum (n = 1), T. tomentosum (n = 2), T. koningii (n = 1), T. atroviride (n = 1), T. viride (n = 1), and T. gamsii (n = 1). Strains expressing extracellular laccase activity were selected by decolorization/oxidation assays in solid media, using azo, anthraquinone, indigoid, and triphenylmethane dyes, and the phenolic substances tannic acid and guaiacol. No strain decolorized Direct Blue 71 or Chicago Blue 6B, but all of them weakly oxidized guaiacol, decolorized Methyl Orange, and efficiently oxidized tannic acid. Based in decolorization/oxidation assays, strains CMU-1 (T. harzianum), CMU-8 (T. atroviride), CMU-218 (T. viride), and CMU-221 (T. tomentosum) were selected for evaluating their extracellular laccase activity in liquid media. Strain CMU-8 showed no basal laccase activity, while strains CMU-1, CMU-218, and CMU-221 had a basal laccase activity of 1,313.88 mU/mL, 763.88 mU/mL, and 799.53 mU/mL, respectively. Addition of sorghum straw inhibited laccase activity in strain CMU-1 by 34%, relative to the basal culture, while strains CMU-8, CMU-21, and CMU-221 increased their laccase activity by 1,321.5%, 64%, and 47%, respectively. These results show that assayed phenolic substrates are good tools for selecting laccase producer strains in Trichoderma. These same assays indicate the potential use of studied strains for bioremediation processes. Straw laccase induction suggests that analyzed strains have potential for straw delignification in biopulping and other biotechnological applications. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:787-798, 2016.
Bennallack, Philip R.; Burt, Scott R.; Heder, Michael J.
Thiopeptides are small (12- to 17-amino-acid), heavily modified peptides of bacterial origin. This antibiotic family, with more than 100 known members, is characterized by the presence of sulfur-containing heterocyclic rings and dehydrated residues within a macrocyclic peptide structure. Thiopeptides, including micrococcin P1, have garnered significant attention in recent years for their potent antimicrobial activity against bacteria, fungi, and even protozoa. Micrococcin P1 is known to target the ribosome; however, like those of other thiopeptides, its biosynthesis and mechanisms of self-immunity are poorly characterized. We have discovered an isolate of Staphylococcus epidermidis harboring the genes for thiopeptide production and self-protection on a 24-kb plasmid. Here we report the characterization of this plasmid, identify the antimicrobial peptide that it encodes, and provide evidence of a target replacement-mediated mechanism of self-immunity. PMID:25313391
Vogel, F; Salmones, D
This paper describes the commercial production of two strains of Pleurotus pulmonarius, selected in the laboratory for their rapid mycelial development and high production of basidiomata, and one commercial strain of Pleurotus ostreatus. Substrate preparation, impact of pathogens and environmental conditions necessary for the production and quality of the fruiting bodies required are discussed.
Wang, Dengfeng; Wang, Zhicai; Yan, Zuoting; Wu, Jianyong; Ali, Tariq; Li, Jianjun; Lv, Yanli; Han, Bo
The emergence of methicillin-resistant Staphylococcus aureus (MRSA) infection in dairy animals is of great concern for livestock and public health. The aim of present study was to detect new trends of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) towards antibiotic susceptibility, resistance genes and molecular typing by methods of disc diffusion, multiplex PCR assay and multilocus sequence typing (MLST). A total of 219 S. aureus strains were isolated from bovine mastitis cases from six provinces of China, including 34 MRSA strains. The results revealed that more than 70% isolated strains showed resistance to various antibiotics, and multiple-drugs resistance to more than five categories of antibiotics was found more common. The ermC was the most prevalent resistance gene, followed by other genes; however, ermA was the least frequently detected gene. Twenty-eight mecA-negative MRSA and six mecA-positive MRSA strains were detected, and in which three strains were ST97-MRSA-IV, others were ST965-MRSA-IV, ST6-MRSA-IV and ST9-MRSA-SCCmec-NT. The mecA-negative MRSA strains were found resistant to most of the antibiotics, and harbored aac(6')/aph(2''), aph(3')-III and tetM genes higher than MSSA strains. The resistance to most of the antibiotics was significantly higher in MRSA than in MSSA strains. The MLST profiles showed that these strains mainly belonged to CC5, CC398, CC121 and CC50 lineage, especially within ST97 and ST398, while some novel sequence types (ST2154, ST2165 and ST2166) were identified and deposited in the MLST database. This indicates that the resistance of S. aureus is becoming more complicated by changes in multi-drug resistance mechanism and appearance of mecA-negative MRSA isolates, and importantly, MRSA-IV strains in different MLST types are emerging.
Khoramian, Babak; Jabalameli, Fereshteh; Niasari-Naslaji, Amir; Taherikalani, Morovat; Emaneini, Mohammad
The aim of this study was to find different prevalence of genes involved in the biofilm formation process and to assess the phenotypic and genotypic markers of biofilm formation among Staphylococcus aureus strains isolated from human and bovine infections. In this study, 215 S. aureus strains were collected from human and dairy cow's infections. The biofilm forming capacity of the strains was evaluated using a colorimetric microtiter plate assay. The genes encoding microbial surface components, recognizing adhesive matrix molecules (MSCRAMMs) (ebpS, eno, fib, fnbA, fnbB, cna and bap), and the intracellular adhesion (ica) genes (icaA, and icaD) were targeted by polymerase chain reaction (PCR)-based method. Approximately 70% of the isolates produced biofilm. Among these, 59.3% were producers of weakly adherent biofilms while 34.8% and 5.8% produced moderate and strong biofilms, respectively. The most prevalent gene was icaD found in 88.4% of the isolates, followed by icaA, fib and eno found in 87.9%, 75.8% and 75.3% of the isolates, respectively. The bap gene was not detected in any of the isolates. The prevalence of ebpS and fnbA genes among bovine isolates were significantly higher than those in human isolates, whilst the prevalence of cna gene was significantly higher in the human isolates. In this study, a high prevalence of biofilm production was found among S. aureus strains isolated from human and bovine infections. Most biofilm producing isolates were positive for MSCRAMM, icaA, and icaD genes.
Ding, Yanpeng; Onodera, Yoshikuni; Lee, Jean C; Hooper, David C
While remaining a major problem in hospitals, Staphylococcus aureus is now spreading in communities. Strain MW2 (USA400 lineage) and other community methicillin-resistant S. aureus strains most commonly cause skin infections with abscess formation. Multidrug resistance (MDR) efflux pumps contribute to antimicrobial resistance but may also contribute to bacterial survival by removal of environmental toxins. In S. aureus, NorA, NorB, NorC, and Tet38 are chromosomally encoded efflux pumps whose overexpression can confer MDR to quinolones and other compounds (Nor pumps) or tetracyclines alone (Tet38), but the natural substrates of these pumps are not known. To determine the role of these efflux pumps in a natural environment in the absence of antibiotics, we used strain MW2 in a mouse subcutaneous abscess model and compared pump gene expression as determined by reverse transcription-PCR in the abscesses and in vitro. norB and tet38 were selectively upregulated in vivo more than 171- and 24-fold, respectively, whereas norA and norC were downregulated. These changes were associated with an increase in expression of mgrA, which encodes a transcriptional regulator known to affect pump gene expression. In competition experiments using equal inocula of a norB or tet38 mutant and parent strain MW2, each mutant exhibited growth defects of about two- to threefold in vivo. In complementation experiments, a single-copy insertion of norB (but not a single-copy insertion of tet38) in the attB site within geh restored the growth fitness of the norB mutant in vivo. Our findings indicate that some MDR pumps, like NorB, can facilitate bacterial survival when they are overexpressed in a staphylococcal abscess and may contribute to the relative resistance of abscesses to antimicrobial therapy, thus linking bacterial fitness and resistance in vivo.
Locke, Jeffrey B; Zuill, Douglas E; Scharn, Caitlyn R; Deane, Jennifer; Sahm, Daniel F; Denys, Gerald A; Goering, Richard V; Shaw, Karen J
The Cfr methyltransferase confers resistance to six classes of drugs which target the peptidyl transferase center of the 50S ribosomal subunit, including some oxazolidinones, such as linezolid (LZD). The mobile cfr gene was identified in European veterinary isolates from the late 1990s, although the earliest report of a clinical cfr-positive strain was the 2005 Colombian methicillin-resistant Staphylococcus aureus (MRSA) isolate CM05. Here, through retrospective analysis of LZD(r) clinical strains from a U.S. surveillance program, we identified a cfr-positive MRSA isolate, 1128105, from January 2005, predating CM05 by 5 months. Molecular typing of 1128105 revealed a unique pulsed-field gel electrophoresis (PFGE) profile most similar to that of USA100, spa type t002, and multilocus sequence type 5 (ST5). In addition to cfr, LZD resistance in 1128105 is partially attributed to the presence of a single copy of the 23S rRNA gene mutation T2500A. Transformation of the ∼37-kb conjugative p1128105 cfr-bearing plasmid from 1128105 into S. aureus ATCC 29213 background strains was successful in recapitulating the Cfr antibiogram, as well as resistance to aminoglycosides and trimethoprim. A 7-kb cfr-containing region of p1128105 possessed sequence nearly identical to that found in the Chinese veterinary Proteus vulgaris isolate PV-01 and in U.S. clinical S. aureus isolate 1900, although the presence of IS431-like sequences is unique to p1128105. The cfr gene environment in this early clinical cfr-positive isolate has now been identified in Gram-positive and Gram-negative strains of clinical and veterinary origin and has been associated with multiple mobile elements, highlighting the versatility of this multidrug resistance gene and its potential for further dissemination.
Lawrence, Laura E; Frosco, MaryBeth; Ryan, Brenda; Chaniewski, Susan; Yang, Hyekyung; Hooper, David C; Barrett, John F
The antistaphylococcal activities of BMS-284756 (T-3811ME), levofloxacin, moxifloxacin, and ciprofloxacin were compared against wild-type and grlA and grlA/gyrA mutant strains of Staphylococcus aureus. BMS-284756 was the most active quinolone tested, with MICs and minimal bactericidal concentrations against S. aureus wild-type strain MT5, grlA mutant MT5224c4, and grlA/gyrA mutant EN8 of 0.03 and 0.06, 0.125 and 0.125, and 4 and 4 microg/ml, respectively. In the time-kill studies, BMS-284756 and levofloxacin exhibited rapid killing against all strains. Ciprofloxacin, however, was not bactericidal for the double mutant, EN8. BMS-284756 and levofloxacin were bactericidal (3 log(10) decrease in CFU/ml) against the MT5 and MT5224c4 strains at two and four times the MIC within 2 to 4 h. Against EN8, BMS-284756 was bactericidal within 4 h at two and four times the MIC, and levofloxacin achieved similar results within 4 to 6 h. Both the wild-type strain MT5 and grlA mutant MT5224c4 should be considered susceptible to both BMS-284756 and levofloxacin, and both quinolones are predicted to have clinical efficacy. The in vivo efficacy of BMS-284756, levofloxacin, and moxifloxacin against S. aureus strain ISP794 and its single mutant 2C6(1)-1 directly reflected the in vitro activity: increased MICs correlated with decreased in vivo efficacy. The 50% protective doses of BMS-284756 against wild-type and mutant strains were 2.2 and 1.6 mg/kg of body weight/day, respectively, compared to the levofloxacin values of 16 and 71 mg/kg/day and moxifloxacin values of 4.7 and 61.6 mg/kg/day. BMS-284756 was more potent than levofloxacin and equipotent with moxifloxacin against ISP794 both in vitro and in vivo, while BMS-284756 was more potent than levofloxacin and moxifloxacin against 2C6(1)-1.
Güler, Ismail; Kılıç, Hüseyin; Atalay, Mustafa Altay; Perçin, Duygu; Erçal, Barış Derya
Methicillin-resistant Staphylococcus aureus (MRSA) infections are associated with increased cost, mortality and length of hospital stay compared with the other infections. Therefore, controlling the spread of this pathogen by screening patients, personnel and the environment remains as a high priority in infection control programs. The aim of this study was to detect the clonal relationship between nosocomial MRSA strains by using repetitive-sequence-based polymerase chain reaction (rep-PCR) method which has several advantages owing to its speed and ease of use. A total of 100 MRSA stock strains that had been isolated from various clinical samples of hospitalized patients in Erciyes University Medical Faculty Hospitals between September 2008-October 2009, were included in the study. Methicillin resistance of the strains were determined by cefoxitin disc diffusion test according to CLSI guidelines. Rep-PCR (Diversilab, bioMerieux, France) method was performed in the following four steps in order to determine genetic proximity of MRSA strains: (1) Manual DNA extraction (UltraClean Microbial DNA Isolation Kit; MoBio Laboratories, USA), (2) Rep-PCR by using fingerprinting kits in the thermocycler (Diversilab DNA Fingerprinting Kit), (3) Automated microfluidic electrophoresis by bioanalyzer (Diversilab DNA LabChip kit), (4) Analysis and rapid evaluation with the use of web-based DiversiLab software (version 2.1.66). Rep-PCR analysis have shown the presence of a total 11 clones, including 3 major clones [A (4 subtypes), B (2 subtypes) and C (2 subtypes)] and 8 unique clones (DK). Clone A was found to be the dominant type. Seventy-eight percent of the 100 MRSA isolates belonged to clone A (63 were A1; 9 were A2; 4 were A3, 2 were A4), 11% belonged to clone B (10 were B1, 1 was B2), 3% belonged to clone C (2 were C1, 1 was C2), and one of each belonged to the other clones (D, E, F, G, H, I, J, K). Clone A was isolated from 93.3% (14/15) of the samples sent from internal
Murfin, Kristen E.; Lee, Ming-Min; McDonald, Bradon R.; Larget, Bret; Forst, Steven; Stock, S. Patricia; Currie, Cameron R.
ABSTRACT Microbial symbionts provide benefits that contribute to the ecology and fitness of host plants and animals. Therefore, the evolutionary success of plants and animals fundamentally depends on long-term maintenance of beneficial associations. Most work investigating coevolution and symbiotic maintenance has focused on species-level associations, and studies are lacking that assess the impact of bacterial strain diversity on symbiotic associations within a coevolutionary framework. Here, we demonstrate that fitness in mutualism varies depending on bacterial strain identity, and this is consistent with variation shaping phylogenetic patterns and maintenance through fitness benefits. Through genome sequencing of nine bacterial symbiont strains and cophylogenetic analysis, we demonstrate diversity among Xenorhabdus bovienii bacteria. Further, we identified cocladogenesis between Steinernema feltiae nematode hosts and their corresponding X. bovienii symbiont strains, indicating potential specificity within the association. To test the specificity, we performed laboratory crosses of nematode hosts with native and nonnative symbiont strains, which revealed that combinations with the native bacterial symbiont and closely related strains performed significantly better than those with more divergent symbionts. Through genomic analyses we also defined potential factors contributing to specificity between nematode hosts and bacterial symbionts. These results suggest that strain-level diversity (e.g., subspecies-level differences) in microbial symbionts can drive variation in the success of host-microbe associations, and this suggests that these differences in symbiotic success could contribute to maintenance of the symbiosis over an evolutionary time scale. PMID:26045536
Mazza, Roberta; Piras, Francesca; Ladu, Daniela; Putzolu, Miriam; Consolati, Simonetta Gianna; Mazzette, Rina
Listeriosis is a foodborne disease caused by Listeria monocytogenes and is considered as a serious health problem, due to the severity of symptoms and the high mortality rate. Recently, other Listeria species have been associated with disease in human and animals. The aim of this study was to develop a multiplex polymerase chain reaction (PCR) in order to simultaneously detect six Listeria species (L. grayi, L. welshimeri, L. ivanovii, L. monocytogenes, L. seeligeri, L. innocua) in a single reaction. One hundred eighteen Listeria spp. strains, isolated from meat products (sausages) and processing plants (surfaces in contact and not in contact with meat), were included in the study. All the strains were submitted to biochemical identification using the API Listeria system. A multiplex PCR was developed with the aim to identify the six species of Listeria. PCR allowed to uniquely identify strains that had expressed a doubtful profile with API Listeria The results suggest that the multiplex PCR could represent a rapid and sensitive screening test, a reliable method for the detection of all Listeria species, both in contaminated food and in clinical samples, and also a tool that could be used for epidemiological purposes in food-borne outbreaks. A further application could be the development of a PCR that can be directly applied to the pre-enrichment broth.
Mazza, Roberta; Ladu, Daniela; Putzolu, Miriam; Consolati, Simonetta Gianna; Mazzette, Rina
Listeriosis is a foodborne disease caused by Listeria monocytogenes and is considered as a serious health problem, due to the severity of symptoms and the high mortality rate. Recently, other Listeria species have been associated with disease in human and animals. The aim of this study was to develop a multiplex polymerase chain reaction (PCR) in order to simultaneously detect six Listeria species (L. grayi, L. welshimeri, L. ivanovii, L. monocytogenes, L. seeligeri, L. innocua) in a single reaction. One hundred eighteen Listeria spp. strains, isolated from meat products (sausages) and processing plants (surfaces in contact and not in contact with meat), were included in the study. All the strains were submitted to biochemical identification using the API Listeria system. A multiplex PCR was developed with the aim to identify the six species of Listeria. PCR allowed to uniquely identify strains that had expressed a doubtful profile with API Listeria The results suggest that the multiplex PCR could represent a rapid and sensitive screening test, a reliable method for the detection of all Listeria species, both in contaminated food and in clinical samples, and also a tool that could be used for epidemiological purposes in food-borne outbreaks. A further application could be the development of a PCR that can be directly applied to the pre-enrichment broth. PMID:27800422
Hoffmann, Anja; Schneider, Tanja; Pag, Ulrike; Sahl, Hans-Georg
Pep5 is a cationic pore-forming lantibiotic produced by Staphylococcus epidermidis strain 5. The producer strain protects itself from the lethal action of its own bacteriocin through the 69-amino-acid immunity peptide PepI. The N-terminal segment of PepI contains a 20-amino-acid stretch of apolar residues, whereas the C terminus is very hydrophilic, with a net positive charge. We used green fluorescent protein (GFP)-PepI fusions to obtain information on its localization in vivo. PepI was found to occur outside the cytoplasm and to accumulate at the membrane-cell wall interface. The extracellular localization appeared essential for conferring immunity. We analyzed the functional role of the specific segments by constructing various mutant peptides, which were also fused to GFP. When the hydrophobic N-terminal segment of PepI was disrupted by introducing charged amino acids, the export of PepI was blocked and clones expressing such mutant peptides were Pep5 sensitive. When PepI was successively shortened at the C terminus, in contrast, its export properties remained unchanged whereas its ability to confer immunity was gradually reduced. The results show that the N-terminal part is required for the transport of PepI and that the C-terminal part is important for conferring the immunity phenotype. A concept based on target shielding is proposed for the PepI immunity mechanism.
Crossley, K; Landesman, B; Zaske, D
Studies to determine the epidemiologic behavior of strains of Staphylococcus aureus resistant to methicillin and aminoglycosides (MARS) were conducted over a period of two and one-half years, during which MARS were isolated from 201 patients at a hospital in the midwestern United States. Most cases of infection or colonization with MARS (156 of 201) occurred in patients with burns. In the burn unit, MARS were recovered from the air, from the hair and hands of personnel, and from inanimate objects. Nasal (72%) and rectal (66%) colonization were common among burned patients with infected or colonized burn wounds but occurred in only six of 74 burn unit personnel. When compared with two control periods, the prophylactic use of antistaphylococcal agents in patients with burns increased markedly at the time the outbreak began. Of the 45 patients without burns from whom MARS were isolated, 42 (93%) were surgical patients. MARS were not demonstrated in the air or environment of patients with infected surgical wounds. None of 334 non-burn unit hospital personnel were found to be carriers of MARS. Four phage types (83A, 6/75/85, 29/52/80, and 92) were recovered during the outbreak. A determinant of antibiotic resistance was probably transmitted among strains of S. aureus.
Tabbene, Olfa; Ben Slimene, Imen; Bouabdallah, Faten; Mangoni, Maria-Luisa; Urdaci, Maria-Camino; Limam, Ferid
B38 bacterial strain, isolated from Tunisian soil showed a strong antimicrobial activity. Based on biochemical characterization and 16S rDNA sequence analysis, B38 strain was identified as Bacillus subtilis. Cell culture supernatant showed antibacterial activity against clinical isolates of methicillin-resistant Staphylococcus species and several Gram-positive and Gram-negative bacteria. Antifungal activity against phytopathogenic fungi was also observed. Antibacterial activity production started at early exponential growth phase, and maximum activity was reached at the stationary phase. This antibacterial activity was neither affected by proteases, lipase, and organic solvents, nor by surfactants. It was stable over a wide pH range and still active after autoclaving at 121 degrees C during 20 min. Thin layer chromatography followed by bioautography assay allowed the detection of four active spots with R(f) values of 0.30, 0.47, 0.70, and 0.82. The single spot with R (f) 0.30 showed antifungal activity, whereas the spots with R(f) values of 0.47, 0.70, and 0.82 exhibited antibacterial activity.
Zhang, Wanjiang; Hao, Zhihui; Wang, Yang; Cao, Xingyuan; Logue, Catherine M; Wang, Bing; Yang, Jing; Shen, Jianzhong; Wu, Congming
The aim of this study was to determine the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) isolates from pet animals and veterinary staff and the characteristics of these isolates. A total of 22 MRSA isolates were isolated from nasal swabs from dogs, cats and veterinary staff in six pet hospitals in six cities, and examined for antimicrobial susceptibility, the presence of resistance genes, Panton-Valentine leukocidin gene lukF-lukS, staphylococcal chromosomal cassette (SCC) mec typing, spa tying, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. Of 22 MRSA isolates, 21 were recovered from pet animals, and one was isolated from a member of sstaff. All 22 MRSA strains were resistant to penicillin, oxacillin, azithromycin, clindamycin and ceftriaxone, and harboured mecA, ermB and linA genes. The lukF-lukS gene was not detected in any of the MRSA isolates. Eighteen MRSA strains from Qingdao belonged to ST59-MRSA-IV-spa t437. Of four MRSA isolates from Beijing, one belonged to ST398-MRSA-V-spa t034, and three belonged to ST239-MRSA-III-spa t030 profiles. Two PFGE types (A and B) were identified. Two isolates originating from dogs and one isolate originating from a staff member in Beijing shared similar PFGE patterns. Our cumulative data suggested that cross-transmission of MRSA may have occurred between pet animals and veterinary staff.
Xu, Jiayi; Hansen, Per Juel; Nielsen, Lasse Tor; Krock, Bernd; Tillmann, Urban; Kiørboe, Thomas
Zooplankton responses to toxic algae are highly variable, even towards taxonomically closely related species or different strains of the same species. Here, the individual level feeding behavior of a copepod, Temora longicornis, was examined which offered 4 similarly sized strains of toxic dinoflagellate Alexandrium spp. and a non-toxic control strain of the dinoflagellate Protoceratium reticulatum. The strains varied in their cellular toxin concentration and composition and in lytic activity. High-speed video observations revealed four distinctly different strain-specific feeding responses of the copepod during 4h incubations: (i) the 'normal' feeding behavior, in which the feeding appendages were beating almost constantly to produce a feeding current and most (90%) of the captured algae were ingested; (ii) the beating activity of the feeding appendages was reduced by ca. 80% during the initial 60min of exposure, after which very few algae were captured and ingested; (iii) capture and ingestion rates remained high, but ingested cells were regurgitated; and (iv) the copepod continued beating its appendages and captured cells at a high rate, but after 60min, most captured cells were rejected. The various prey aversion responses observed may have very different implications to the prey and their ability to form blooms: consumed but regurgitated cells are dead, captured but rejected cells survive and may give the prey a competitive advantage, while reduced feeding activity of the grazer may be equally beneficial to the prey and its competitors. These behaviors were not related to lytic activity or overall paralytic shellfish toxins (PSTs) content and composition and suggest that other cues are responsible for the responses.
Roberts, Scott; O'Shea, Kathleen; Morris, Daniel; Robb, Andrew; Morrison, Donald; Rankin, Shelley
Recent reports suggest that methicillin-resistant strains of Staphylococcus schleiferi subspecies coagulans are now commonly isolated from dogs. Given the association of a potentially mobile SCCmec type IV element with lysogenic phage-encoded Panton Valentine Leukocidin (PVL) toxin genes in community-acquired methicillin-resistant Staphylococcus aureus strains we hypothesized that methicillin-resistant S. schleiferi ssp. coagulans strains may also encode PVL toxin genes. Forty S. schleiferi ssp. coagulans strains isolated from companion animals were studied. Susceptibility to oxacillin was determined by broth microdilution and all isolates were screened by PCR for the presence of the mecA gene. SCCmec typing was performed on 14 isolates. A real-time PCR assay was developed for the detection of the PVL genes using a SmartCycler. Pulsed-field gel electrophoresis (PFGE) was performed to determine whether S. schleiferi ssp. coagulans strains were homogeneous. Twenty-eight of the 40 isolates (70%) were resistant to oxacillin and 26/28 possessed the mecA gene by PCR. SCCmec IV was identified in seven strains; the other seven isolates were not typable by this technique. All 40 strains were negative for the PVL toxin gene. PFGE showed a heterogeneous population and 13 different profiles were determined. In conclusion, this study showed that PVL toxin genes were not detected in a heterogeneous population of methicillin-resistant S. schleiferi ssp. coagulans strains isolated from companion animals.
El Bayomi, Rasha M; Ahmed, Heba A; Awadallah, Maysa A I; Mohsen, Rasha A; Abd El-Ghafar, Abeer E; Abdelrahman, Mahmoud A
Staphylococcus aureus in food is a consequence of inadequate hygienic handling and processing, posing a potential risk to public health. The current study aimed to characterize virulence factors, as well as antimicrobial resistance of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) isolated from retail chicken products and hand swabs from vendors in Egypt. In addition, genetic relatedness of the isolates from chicken and humans was evaluated by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using protein A as a target. A total of 110 samples were collected from chicken products (n = 80) and vendors (n = 30). Overall, 30 (37.5%) chicken products samples were positive for S. aureus, whereas hand swabs from meat handlers revealed that 18 (60%) were positive. Ten MRSA strains were characterized by the presence of the mecA gene, comprising seven isolates from chicken and three from humans. Virulence-associated factors were evaluated by PCR, revealing that 31.3% of S. aureus isolates harbored the Panton-Valentine leukocidin (PVL) gene, whereas 10.4% were positive for the sea and sed genes each, and only two isolates were positive for γ-hemolysin-associated gene. Genotyping using spa PCR-RFLP showed identical restriction banding patterns of MRSA isolates of human and chicken meat origin, indicating the genetic relatedness of the isolates. To the best of our knowledge, this is the first study to characterize PVL-positive MRSA from chicken products and to utilize spa-RFLP for evaluating the genetic relatedness between MRSA of human and chicken origin in Egypt.
Młynarczyk, A; Młynarczyk, G; Jeljaszewicz, J
In mixed cultures of staphylococci a transfer of the resistance to methicillin and penicillinase plasmids as well as tetracycline and chloramphenicol plasmids was investigated. It was shown that the resistance to methicillin was transferred in mixed cultures from one strain of S. aureus to another and from S. epidermidis to S. aureus. In both cases transfer of methicillin resistance required, the presence of penicillinase plasmid in recipient or donor strain. In the case of other markers transmission was independent. Moreover it was shown that the transfer of resistance genes in mixed cultures was mediated by bacteriophage of the serologic group A.
Zobba, Rosanna; Anfossi, Antonio G; Pinna Parpaglia, Maria Luisa; Dore, Gian Mario; Chessa, Bernardo; Spezzigu, Antonio; Rocca, Stefano; Visco, Stefano; Pittau, Marco; Alberti, Alberto
Few data are available on the prevalence and molecular typing of species belonging to the genus Anaplasma in Mediterranean ruminants. In this study, PCR analysis and sequencing of both 16S rRNA and groEL genes were combined to investigate the presence, prevalence, and molecular traits of Anaplasma spp. in ruminants sampled on the Island of Sardinia, chosen as a subtropical representative area. The results demonstrate a high prevalence of Anaplasma spp. in ruminants, with animals infected by at least four of six Anaplasma species (Anaplasma marginale, A. bovis, A. ovis, and A. phagocytophilum). Moreover, ruminants host a number of neutrophil-tropic strains genetically closely related to the canine pathogen A. platys. The high Anaplasma spp. prevalence and the identification of as-yet-unclassified neutrophil-tropic strains raise concerns about the specificity of serological tests routinely used in ruminants and provide additional background for reconstructing the evolutionary history of species genetically related to A. phagocytophilum.
Kizerwetter-Świda, Magdalena; Chrobak-Chmiel, Dorota; Rzewuska, Magdalena; Binek, Marian
We investigated in vitro activity of a novel veterinary fluoroquinolone, pradofloxacin, against methicillin-resistant Staphylococcus pseudintermedius (MRSP) isolates and compared with other fluoroquinolones. A total of 38 MRSP isolates were subjected to agar disk diffusion tests for sensitivity to pradofloxacin, orbifloxacin, marbofloxacin, enrofloxacin, and ciprofloxacin. The minimal inhibitory concentration (MIC) values of pradofloxacin, ciprofloxacin, and enrofloxacin were determined. Mutations in the genes encoding DNA gyrase subunit A (GyrA) and topoisomerase IV (GrlA) proteins associated with fluoroquinolone resistance were studied by an analysis of partial sequences of the genes encoding these proteins. Two MRSP isolates were susceptible in disk diffusion and microdilution test to all fluoroquinolones tested, including pradofloxacin. Based on the results of the disk diffusion testing, 33 of 38 isolates showed resistance to pradofloxacin and 3 were intermediate, whereas, by pradofloxacin MIC testing, 35 isolates were classified as resistant and 1 as intermediate. Single alterations in GyrA and GrlA proteins were observed in the 35 resistant isolates and the 1 intermediate isolate (MIC results). These same 36 isolates were also resistant to the other tested fluoroquinolones. The results of the current study showed that MRSP isolates are usually resistant to all fluoroquinolones, including pradofloxacin. Therefore, in routine susceptibility testing to pradofloxacin by disk diffusion, the results should be carefully interpreted for MRSP isolates, especially those resistant to other fluoroquinolones and, in questionable cases, the pradofloxacin MIC should be determined to confirm the susceptibility testing results.
Cheng, Nai-Chen; Wang, Jann-Tay; Chang, Shan-Chwen; Tai, Hao-Chih; Tang, Yueh-Bih
Staphylococcus aureus is an uncommon causative agent of monomicrobial necrotizing fasciitis, but we have noted several cases over the years. The patients treated for necrotizing fasciitis between January 1998 and December 2008 in our institution were identified, and their medical records were reviewed. Of 105 necrotizing fasciitis cases during the study period, 18 were caused by monomicrobial S. aureus infection (17%). The median age was 62 years (range, 12-81 years). Among this cohort, 10 patients had coexisting medical conditions or risk factors, including diabetes and hypertension. Lower limbs and upper limbs are the most commonly involved sites. Among the bacterial isolates from these cases, 8 were methicillin-sensitive S. aureus (MSSA) and 10 were methicillin-resistant S. aureus (MRSA). One patient died in the MSSA group, and 5 patients died in the MRSA group. The mortality rate and other clinical characteristics were not significantly different between the 2 groups. However, all MRSA necrotizing fasciitis developed after the year 2000, and it was significantly different from MSSA necrotizing fasciitis that predominantly took place before the year 2000. In conclusion, S. aureus is an important pathogen of monomicrobial necrotizing fasciitis, and MRSA has emerged as the predominant causative agent in recent years. Therefore, MRSA-directed antibiotic therapy should be considered when treating patients suspected with necrotizing fasciitis in endemic areas.
Cushnie, T P T; Lamb, A J
The flavonol galangin is present in numerous plants and is a major constituent of Helichrysum aureonitens, a perennial herb used by South African indigenes to treat infection. In the present study, the antibacterial activity of galangin was assessed against 17 strains of 4-quinolone resistant S. aureus using an agar dilution assay. It was determined that the flavonol had a minimum inhibitory concentration (MIC) of approximately 50 microg/ml against 16 of these strains, including those which exhibited 250- and 500-fold increases in norfloxacin resistance. The remaining one strain, which possessed an amino acid alteration in the GrlB subunit of topoisomerase IV, had increased susceptibility to galangin. Control strains of 4-quinolone sensitive S. aureus were also found to have MICs of 50 microg/ml. The topoisomerase IV enzyme may therefore be implicated in the antibacterial mechanism of action of galangin. Clearly however, there is no cross-resistance between galangin and the 4-quinolones, and the flavonol therefore warrants further investigation as an antibacterial agent.
Duncan, I. B. R.; Comtois, R. D.
A survey was made of the phage-types of staphylococci responsible for cross-infection in a large veterans' hospital between 1961 and 1964. An earlier survey had shown that in 1959 most of the infections were caused by staphylocci of the “80/81/82” group. In 1961 a new group of staphylococci were first recognized and provisionally designated as “Atypical Group III” strains; these were non-typable by the usual typing phages but showed inhibition patterns with some of the Group III phages. The “Atypical Group III” staphylococci all showed one or other of four patterns of multiple antibiotic resistance. By 1963 these resistant “Atypical Group III” staphylococci had become more frequent than “80/81/82” strains as causative agents of cross-infection, although both groups have continued to cause infections in the hospital. “Atypical Group III” strains mainly infected surgical wounds and skin ulcers, whereas “80/81/82” strains commonly produced primary skin sepsis, such as boils. PMID:4952367
Embleton, Michelle L; Nair, Sean P; Heywood, Wendy; Menon, Dev C; Cookson, Barry D; Wilson, Michael
Light-activated antimicrobial agents (photosensitizers) are promising alternatives to antibiotics for the treatment of topical infections. To improve efficacy and avoid possible damage to host tissues, targeting of the photosensitizer to the infecting organism is desirable, and this has previously been achieved using antibodies and chemical modification of the agent. In this study we investigated the possibility of using a bacteriophage to deliver the photosensitizer tin(IV) chlorin e6 (SnCe6) to Staphylococcus aureus. SnCe6 was covalently linked to S. aureus bacteriophage 75, and the ability of the conjugate to kill various strains of S. aureus when exposed to red light was determined. Substantial kills of methicillin- and vancomycin-intermediate strains of S. aureus were achieved using low concentrations of the conjugate (containing 1.5 microg/ml SnCe6) and low light doses (21 J/cm2). Under these conditions, the viability of human epithelial cells (in the absence of bacteria) was largely unaffected. On a molar equivalent basis, the conjugate was a more effective bactericide than the unconjugated SnCe6, and killing was not growth phase dependent. The conjugate was effective against vancomycin-intermediate strains of S. aureus even after growth in vancomycin. The results of this study have demonstrated that a bacteriophage can be used to deliver a photosensitizer to a target organism, resulting in enhanced and selective killing of the organism. Such attributes are desirable in an agent to be used in the photodynamic therapy of infectious diseases.
Sabat, Artur; Melles, Damian C; Martirosian, Gayane; Grundmann, Hajo; van Belkum, Alex; Hryniewicz, Waleria
The sdr locus was found in all 497 investigated Staphylococcus aureus strains, although in 29 strains it contained only the sdrC gene (sdrD negative, sdrE negative). The sdrC-positive, sdrD-negative, sdrE-negative gene profile was exclusive to methicillin-sensitive S. aureus (MSSA) strains (Fisher's exact test; P = 0.0005) and was not found in the strains collected from bone infections (P = 0.0019). We also found a strong association between the presence of the sdrD gene and methicillin-resistant S. aureus strains (P < 0.0001). Our findings suggest that MSSA strains with the newly uncovered sdrC-positive, sdrD-negative, sdrE-negative gene profile have a substantially decreased potential to establish bone infection.
Hattangady, Dipti S.; Singh, Atul K.; Muthaiyan, Arun; Jayaswal, Radheshyam K.; Gustafson, John E.; Ulanov, Alexander V.; Li, Zhong; Wilkinson, Brian J.; Pfeltz, Richard F.
Complete genome comparisons, transcriptomic and metabolomic studies were performed on two laboratory-selected, well-characterized vancomycin-intermediate Staphylococcus aureus (VISA) derived from the same parent MRSA that have changes in cell wall composition and decreased autolysis. A variety of mutations were found in the VISA, with more in strain 13136p−m+V20 (vancomycin MIC = 16 µg/mL) than strain 13136p−m+V5 (MIC = 8 µg/mL). Most of the mutations have not previously been associated with the VISA phenotype; some were associated with cell wall metabolism and many with stress responses, notably relating to DNA damage. The genomes and transcriptomes of the two VISA support the importance of gene expression regulation to the VISA phenotype. Similarities in overall transcriptomic and metabolomic data indicated that the VISA physiologic state includes elements of the stringent response, such as downregulation of protein and nucleotide synthesis, the pentose phosphate pathway and nutrient transport systems. Gene expression for secreted virulence determinants was generally downregulated, but was more variable for surface-associated virulence determinants, although capsule formation was clearly inhibited. The importance of activated stress response elements could be seen across all three analyses, as in the accumulation of osmoprotectant metabolites such as proline and glutamate. Concentrations of potential cell wall precursor amino acids and glucosamine were increased in the VISA strains. Polyamines were decreased in the VISA, which may facilitate the accrual of mutations. Overall, the studies confirm the wide variability in mutations and gene expression patterns that can lead to the VISA phenotype. PMID:27025616
Gómez, Paula; Lozano, Carmen; Benito, Daniel; Estepa, Vanesa; Tenorio, Carmen; Zarazaga, Myriam; Torres, Carmen
The objective of this study was to determine the prevalence of Staphylococcus in urban wastewater treatment plants (UWTP) of La Rioja (Spain), and to characterize de obtained isolates. 16 wastewater samples (8 influent, 8 effluent) of six UWTPs were seeded on mannitol-salt-agar and oxacillin-resistance-screening-agar-base for staphylococci and methicillin-resistant Staphylococcus aureus recovery. Antimicrobial susceptibility profile was determined for 16 antibiotics and the presence of 35 antimicrobial resistance genes and 14 virulence genes by PCR. S. aureus was typed by spa, agr, and multilocus-sequence-typing, and the presence of immune-evasion-genes cluster was analyzed. Staphylococcus spp. were detected in 13 of 16 tested wastewater samples (81%), although the number of CFU/mL decreased after treatment. 40 staphylococci were recovered (1-5/sample), and 8 of them were identified as S. aureus being typed as (number of strains): spa-t011/agr-II/ST398 (1), spa-t002/agr-II/ST5 (2), spa-t3262/agr-II/ST5 (1), spa-t605/agr-II/ST126 (3), and spa-t878/agr-III/ST2849 (1). S. aureus ST398 strain was methicillin-resistant and showed a multidrug resistance phenotype. Virulence genes tst, etd, sea, sec, seg, sei, sem, sen, seo, and seu, were detected among S. aureus and only ST5 strains showed genes of immune evasion cluster. Thirty-two coagulase-negative Staphylococcus of 12 different species were recovered (number of strains): Staphylococcus equorum (7), Staphylococcus vitulinus (4), Staphylococcus lentus (4), Staphylococcus sciuri (4), Staphylococcus fleurettii (2), Staphylococcus haemolyticus (2), Staphylococcus hominis (2), Staphylococcus saprophyticus (2), Staphylococcus succinus (2), Staphylococcus capitis (1), Staphylococcus cohnii (1), and Staphylococcus epidermidis (1). Five presented a multidrug resistance phenotype. The following resistance and virulence genes were found: mecA, lnu(A), vga(A), tet(K), erm(C), msr(A)/(B), mph(C), tst, and sem. We found that
Parker, M D; Barrett, P I; Shepherd, J; Price, L J; Bull, S D
Under many of the conditions studied, a two-strain cocktail of non-toxigenic Clostridium spp. was found to be suitable as a surrogate for non-proteolytic Clostridium botulinum, and has the potential for use in chilled food challenge tests measuring growth. Non-toxigenic surrogates could also be used in thermal process screening studies.
Gocheva, Yana G; Krumova, Ekaterina Tz; Slokoska, Lyudmila S; Miteva, Jeny G; Vassilev, Spassen V; Angelova, Maria B
The effect of growth temperature (10, 15, 20, 25, and 30 degrees C) on the cell response was compared between two Antarctic Penicillium sp. strains (Penicillium sp. p14 and Penicillium sp. m12) and a European temperate strain, Penicillium sp. t35. According to the temperature profiles, Penicillium sp. p14 was identified as psychrophilic, while Penicillium sp. m12 and Penicillium sp. t35 as mesophilic fungi, respectively. The results demonstrated that the growth at low temperature does clearly induce oxidative stress events in all strains tested. Decreases in growth temperature below the optimal coincided with markedly enhanced protein carbonyl content, an indicator of oxidatively damaged proteins. Also, the cellular response to growth temperature in terms of reserve carbohydrate was determined. In the mesophilic strains there was essentially no enhancement of glycogen content. This was in contrast to the psychrophilic Penicillium sp. p14, which gradually accumulated glycogen in response to cold (10 degrees C) during the exponential phase. In addition, elevated endogenous levels of trehalose upon low-temperature stress were exhibited by all model microorganisms. Compared with temperate mesophilic Penicillium sp. t35, Antarctic strains (psychrophilic Penicillium sp. p14 and mesophilic Penicillium sp. m12) demonstrated a marked rise in activities of protective enzymes such as superoxide dismutase and catalase at decreasing temperatures. The results suggested that low-temperature resistance is partially associated with enhanced scavenging systems.
Mesorhizobium loti strain R7A was isolated in 1993 in Lammermoor, Otago, New Zealand from a Lotus corniculatus root nodule and is a reisolate of the inoculant strain ICMP3153 (NZP2238) used at the site. R7A is an aerobic, Gram-negative, non-spore-forming rod. The symbiotic genes in the strain are carried on a 502-kb integrative and conjugative element known as the symbiosis island or ICEMlSymR7A. M. loti is the microsymbiont of the model legume Lotus japonicus and strain R7A has been used extensively in studies of the plant-microbe interaction. This report reveals that the genome of M. loti strain R7A does not harbor any plasmids and contains a single scaffold of size 6,529,530 bp which encodes 6,323 protein-coding genes and 75 RNA-only encoding genes. This rhizobial genome is one of 100 sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project. PMID:25780499
Kelly, Simon; Sullivan, John; Ronson, Clive; Tian, Rui; Bräu, Lambert; Munk, Christine; Goodwin, Lynne; Han, Cliff; Woyke, Tanja; Reddy, Tatiparthi; Huntemann, Marcel; Pati, Amrita; Mavromatis, Konstantinos; Markowitz, Victor; Ivanova, Natalia; Kyrpides, Nikos; Reeve, Wayne
Mesorhizobium loti strain R7A was isolated in 1993 in Lammermoor, Otago, New Zealand from a Lotus corniculatus root nodule and is a reisolate of the inoculant strain ICMP3153 (NZP2238) used at the site. R7A is an aerobic, Gram-negative, non-spore-forming rod. The symbiotic genes in the strain are carried on a 502-kb integrative and conjugative element known as the symbiosis island or ICEMlSym(R7A). M. loti is the microsymbiont of the model legume Lotus japonicus and strain R7A has been used extensively in studies of the plant-microbe interaction. This report reveals that the genome of M. loti strain R7A does not harbor any plasmids and contains a single scaffold of size 6,529,530 bp which encodes 6,323 protein-coding genes and 75 RNA-only encoding genes. This rhizobial genome is one of 100 sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project.
Dourado, M N; Franco, M R; Peters, L P; Martins, P F; Souza, L A; Piotto, F A; Azevedo, R A
Increased agriculture production associated with intense application of herbicides, pesticides, and fungicides leads to soil contamination worldwide. Nickel (Ni), due to its high mobility in soils and groundwater, constitutes one of the greatest problems in terms of environmental pollution. Metals, including Ni, in high concentrations are toxic to cells by imposing a condition of oxidative stress due to the induction of reactive oxygen species (ROS), which damage lipids, proteins, and DNA. This study aimed to characterize the Ni antioxidant response of two tolerant Burkholderia strains (one isolated from noncontaminated soil, SNMS32, and the other from contaminated soil, SCMS54), by measuring superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione S-transferase (GST) activities. Ni accumulation and bacterial growth in the presence of the metal were also analyzed. The results showed that both strains exhibited different trends of Ni accumulation and distinct antioxidant enzymes responses. The strain from contaminated soil (SCMS54) exhibited a higher Ni biosorption and exhibited an increase in SOD and GST activities after 5 and 12 h of Ni exposure. The analysis of SOD, CAT, and GR by nondenaturing PAGE revealed the appearance of an extra isoenzyme in strain SCMS54 for each enzyme. The results suggest that the strain SCMS54 isolated from contaminated soil present more plasticity with potential to be used in soil and water bioremediation.
Mathew, Dony Chacko; Ho, Ying-Ning; Gicana, Ronnie Gicaraya; Mathew, Gincy Marina; Chien, Mei-Chieh; Huang, Chieh-Chen
Though heavy metal such as mercury is toxic to plants and microorganisms, the synergistic activity between them may offer benefit for surviving. In this study, a mercury-reducing bacterium, Photobacterium spp. strain MELD1, with an MIC of 33 mg . kg-1 mercury was isolated from a severely mercury and dioxin contaminated rhizosphere soil of reed (Phragmites australis). While the whole genome sequencing of MELD1 confirmed the presence of a mer operon, the mercury reductase MerA gene showed 99% sequence identity to Vibrio shilloni AK1 and implicates its route resulted from the event of horizontal gene transfer. The efficiency of MELD1 to vaporize mercury (25 mg . kg-1, 24 h) and its tolerance to toxic metals and xenobiotics such as lead, cadmium, pentachlorophenol, pentachloroethylene, 3-chlorobenzoic acid, 2,3,7,8-tetrachlorodibenzo-p-dioxin and 1,2,3,7,8,9-hexachlorodibenzo-p-dioxin is promising. Combination of a long yard bean (Vigna unguiculata ssp. Sesquipedalis) and strain MELD1 proved beneficial in the phytoprotection of mercury in vivo. The effect of mercury (Hg) on growth, distribution and tolerance was examined in root, shoot, leaves and pod of yard long bean with and without the inoculation of strain MELD1. The model plant inoculated with MELD1 had significant increases in biomass, root length, seed number, and increased mercury uptake limited to roots. Biolog plate assay were used to assess the sole-carbon source utilization pattern of the isolate and Indole-3-acetic acid (IAA) productivity was analyzed to examine if the strain could contribute to plant growth. The results of this study suggest that, as a rhizosphere-associated symbiont, the synergistic activity between the plant and MELD1 can improve the efficiency for phytoprotection, phytostabilization and phytoremediation of mercury. PMID:25816328
Pérez-Valdespino, Abigail; Lazarini-Martínez, Alfredo; Rivera-González, Alejandro X.; García-Hernández, Normand; Curiel-Quesada, Everardo
Integrons are non-mobile bacterial genetic elements that carry different cassettes conferring antibiotic resistance. Cassettes can excise or integrate by action of an integron-encoded integrase, enabling bacteria to face environmental challenges. In this work, the functionality and dynamics of two integrons carrying the same cassette arrangement (dfrA12–orfF–aadA2), but located on plasmid or chromosome in two different strains were studied. In order to demonstrate the functionality of the Class 1 integrase, circular cassette integration intermediaries were PCR amplified by PCR using extrachromosomal DNA extracted from bacteria grown in the presence or absence of cassette-encoded antibiotics. Circular aadA2 and dfrA12–orfF–aadA2 cassettes were detected in cultures grown either in the presence or absence of antibiotics in both strains. No dfrA12–orfF circular intermediates could be detected under any culture conditions. These results show that both integrons are functional. However, these elements show different dynamics and functionality since the presence of streptomycin led to detectable gene rearrangements in the variable region only in the strain with the plasmid-born integron. In addition, complete integration products were demonstrated using a receptor molecule carrying an empty integron. In this case, integration products were observed in both strains even in the absence of antibiotics, but they were more evident in the strain with the plasmid-located integron when streptomycin was present in the culture medium. This suggests that integrons in the two strains respond differently to streptomycin even though DNA sequences upstream the intI1 gene, including the lexA boxes of both integrons are identical. PMID:27733851
Attien, Paul; Sina, Haziz; Moussaoui, Wardi; Zimmermann-Meisse, Gaëlle; Dadié, Thomas; Keller, Daniel; Riegel, Philippe; Edoh, Vincent; Kotchoni, Simeon O.; Djè, Marcellin; Prévost, Gilles
The aim of our study was to investigate the microbial quality of meat products and on some clinical samples in Abidjan focused on Staphylococcus genus and the toxin production profile of Staphylococcus aureus (S. aureus) isolated. Bacteria were collected from 240 samples of three meat products sold in Abidjan and 180 samples issued from clinical infections. The strains were identified by both microbiological and MALDI-TOF-MS methods. The susceptibility to antibiotics was determined by the disc diffusion method. The production of Panton-Valentine Leukocidin, LukE/D, and epidermolysins was screened using radial gel immunodiffusion. The production of staphylococcal enterotoxins and TSST-1 was screened by a Bio-Plex Assay. We observed that 96/240 of meat samples and 32/180 of clinical samples were contaminated by Staphylococcus. Eleven species were isolated from meats and 4 from clinical samples. Forty-two S. aureus strains were isolated from ours samples. Variability of resistance was observed for most of the tested antibiotics but none of the strains displays a resistance to imipenem and quinolones. We observed that 89% of clinical S. aureus were resistant to methicillin against 58% for those issued from meat products. All S. aureus isolates issued from meat products produce epidermolysins whereas none of the clinical strains produced these toxins. The enterotoxins were variably produced by both clinical and meat product samples. PMID:24987686
Argudín, M. A.; Mendoza, M. C.; González-Hevia, M. A.; Bances, M.; Guerra, B.
Staphylococcal food poisoning, one of the most common food-borne diseases, results from ingestion of one or more staphylococcal enterotoxins (SEs) produced by Staphylococcus aureus in foods. In the present study, 64 S. aureus isolates recovered from foods and food handlers, associated or not associated with food-poisoning outbreaks in Spain, were investigated. They were assigned to 31 strains by spa typing, multilocus sequence typing (MLST), exotoxin gene content, and antimicrobial resistance. The strains belonged to 10 clonal complexes (CCs): CC5 (29.0%), CC30 (25.8%), CC45 (16.1%), CC8, CC15 (two strains each), CC1, CC22, CC25, CC59, and CC121 (one strain each). They contained hemolysin genes (90.3%); lukED (77.4%); exfoliatin genes eta, etd (6.5% each), and etb (3.2%); tst (25.8%); and the following enterotoxin or enterotoxin-like genes or clusters: sea (38.7%), seb (12.9%), sec (16.1%), sed-selj with or without ser (22.9%), selk-selq (6.5%), seh, sell, selp (9.7% each), egc1 (32.3%), and egc2 (48.4%). The number of se and sel genes ranged from zero to 12. All isolates carrying tst, and most isolates with genes encoding classical enterotoxins (SEA, SEB, SEC, and SED), expressed the corresponding toxin(s). Two CC5 isolates from hamburgers (spa type t002, sequence type 5 [ST5]; spa type t2173, ST5) were methicillin resistant and harbored staphylococcal cassette chromosome mec (SCCmec) IVd. Six (19.4%) were mupirocin resistant, and one (spa type t120, ST15) from a food handler carried mupA (MIC, 1,250 μg/ml). Resistance to ampicillin (blaZ) (61.3%), erythromycin (ermA-ermC or ermC) (25.8%), clindamycin (msrA-msrB or msrB) (16.1%), tetracycline (tetK) (3.2%), and amikacin-gentamicin-kanamycin-tobramycin (aphA with aacA plus aphD or aadD) (6.5%) was also observed. The presence of S. aureus strains with an important repertoire of virulence and resistance determinants in the food chain represents a potential health hazard for consumers and merits further observation
Marek, Agnieszka; Stepień-Pyśniak, Dagmara; Pyzik, Ewelina; Adaszek, Łukasz; Wilczyński, Jarosław; Winiarczyk, Stanisław
In the pathology of poultry, infections caused by Staphylococcus spp. are taking on increasing significance. Although the Staphylococcus species most frequently isolated from these animals is Staphylococcus aureus, the literature data indicate that other species, both coagulase-positive and coagulase-negative, can also cause infections in birds. The aim of the study was to assess the frequency of occurrence of Staphylococcus infections in various poultry species in Western Poland and to test the susceptibility of isolated strains to selected antibiotics. The results obtained showed a relatively high rate of Staphylococcus infection in the poultry. From 2805 samples tested 302 strains (10.8%) of Staphylococcus were isolated. As many as 25 Staphylococcus species were distinguished among the strains isolated. S. cohnii (23.50%), S. aureus (15.89%) and S. lentus (13.90%) accounted for the highest percentages. Over half of the isolated staphylococci exhibited resistance to five of the antibiotics applied, with the highest percentage of resistant strains, 65%, noted for enrofloxacin.
Sudagidan, Mert; Yemenicioğlu, Ahmet
Effects of nisin and lysozyme on growth inhibition and biofilm formation capacity of 25 Staphylococcus aureus strains isolated from raw milk (13 strains) and cheese (12 strains) were studied. Nisin was tested at concentrations between 0.5 and 25 μg/ml; the growth of all strains was inhibited at 25 μg/ml, but the resistances of strains showed a great variation at lower nisin concentrations. In contrast, lysozyme tested at concentrations up to 5.0 mg/ml showed no inhibition on the growth of strains. Nisin used at the growth inhibitory concentration prevented the biofilm formation of strains, but strains continued biofilm formation at subinhibitory nisin concentrations. Lysozyme did not affect the biofilm formation of 19 of the strains, but it caused a considerable activation in the biofilm formation capacity of six strains. Twelve of the strains contained both biofilm-related protease genes (sspA, sspB, and aur) and active proteases; eight of these strains were nisin resistant. These results suggest a potential risk of S. aureus growth and biofilm formation when lysozyme is used in the biopreservation of dairy products. Nisin can be used to control growth and biofilm formation of foodborne S. aureus, unless resistance against this biopreservative develops.
Gallon, Olivier; Pina, Patrick; Gravet, Alain; Laurent, Frederic; Lamy, Brigitte; Delarbre, Jean-Marie; Doucet-Populaire, F; Decousser, J W
The performance of the MicroScan WalkAway PC30 panel for detection of oxacillin resistance was evaluated by use of a collection of 420 staphylococcus isolates. The addition of a cefoxitin test (4 mg/liter) to the oxacillin MIC determination increased its raw performance for Staphylococcus aureus; additional data were required for coagulase-negative staphylococci.
de Souza, Roberta Barreiros; Magnani, Marciane; Ferrari, Rafaela Gomes; Kottwitz, Luciana Bill Mikito; Sartori, Daniele; Tognim, Maria Cristina Bronharo; de Oliveira, Tereza Cristina R. M.
Mutations into codons Aspartate-87 (62%) and Serine-83 (38%) in QRDR of gyrA were identified in 105 Salmonella strains resistant to nalidixic acid (94 epidemic and 11 of poultry origin). The results show a high incidence of mutations associated to quinolone resistance but suggest association with others mechanisms of resistance. PMID:24031623
We investigated the potential production and desiccation tolerance of microsclerotia (MS) by Brazilian strains of Metarhizium. anisopliae [Ma], M. acridum [Mc] and M. robertsii [Mr]. These fungi were grown in a liquid medium containing 16 g carbon l-1 with a carbon:nitrogen ratio of 50:1. One hundre...
Úbeda, Juan F; Chacón-Ocaña, Maria; Díaz-Hellín, Patricia; Ramírez-Pérez, Hector; Briones, Ana
In this study, the biodiversity and some interesting phenotypic properties of Saccharomyces wild yeasts isolated in distilleries, at least 100 years old, located in La Mancha (Spain), were determined. Strains were genetically characterized by RFLP-mtDNA, which confirmed a great genetic biodiversity with 73% of strains with different mtDNA profiles, highlighting the large variability found in sweet and fermented piquette substrata. The predominant species identified was S. cerevisiae, followed by S. paradoxus and S. bayanus Due to the residual sugar-alcohol extraction process using warm water, a great number of thermophilic Saccharomyces strains with a great cell vitality were found to have potential use as starters in distillery plants. Interesting technological properties such as cell vitality and growth rate at different temperatures were studied. The thermal washing process for the extraction of alcohol and reducing sugars of some raw materials contributes to the presence of Saccharomyces strains with technologically interesting properties, especially in terms of vitality and resistance to high temperatures. Due to the fact that fermentation is spontaneous, the yeast biota of these environments, Saccharomyces and non-Saccharomyces, is very varied so these ecological niches are microbial reserves of undoubted biotechnological interest.
Snoussi, Mejdi; Dehmani, Ameni; Noumi, Emira; Flamini, Guido; Papetti, Adele
In this study, we evaluated the antibacterial activity of parsley and basilic essential oils tested against Vibrio strains and their abilities to inhibit and eradicate the mature biofilm using the XTT assay. Petroselinum crispum essential oil was characterized by 1,3,8-p-menthatriene (24.2%), β-phellandrene (22.8%), apiol (13.2%), myristicin (12.6%) and terpinolene (10.3%) as a major constituents. While, in the basilic oil, linalool (42.1%), (E)-methylcinnamate (16.9%) and 1-8 cineole (7.6%) were the main ones. These two essential oils exhibit high anti-Vibrio spp. activity with varying magnitudes. All microorganisms were strongly affected indicating an appreciable antimicrobial potential of basilic with a diameter of inhibition zones growth ranging from 8.67 to 23.33 mm and MIC and MBC values ranging from (0.023-0.047 mg/ml) and (>3->24 mg/ml), respectively. The two essential oils can inhibit and eradicate the mature biofilm formed on polystyrene surface even at low concentrations, with high magnitude for Ocimum basilicum essential oil. This study gives a better insight into the anti-Vibrio activity of parsley and basilc oils and the possibility of their use to prevent and eradicate contamination of sea products by these strains.
Lorite, María J; Muñoz, Socorro; Olivares, José; Soto, María J; Sanjuán, Juan
Lotus species are forage legumes with potential as pastures in low-fertility and environmentally constrained soils, owing to their high persistence and yield under those conditions. The aim of this work was the characterization of phenetic and genetic diversity of salt-tolerant bacteria able to establish efficient symbiosis with Lotus spp. A total of 180 isolates able to nodulate Lotus corniculatus and Lotus tenuis from two locations in Granada, Spain, were characterized. Molecular identification of the isolates was performed by repetitive extragenic palindromic PCR (REP-PCR) and 16S rRNA, atpD, and recA gene sequence analyses, showing the presence of bacteria related to different species of the genus Mesorhizobium: Mesorhizobium tarimense/Mesorhizobium tianshanense, Mesorhizobium chacoense/Mesorhizobium albiziae, and the recently described species, Mesorhizobium alhagi. No Mesorhizobium loti-like bacteria were found, although most isolates carried nodC and nifH symbiotic genes closely related to those of M. loti, considered the type species of bacteria nodulating Lotus, and other Lotus rhizobia. A significant portion of the isolates showed both high salt tolerance and good symbiotic performance with L. corniculatus, and many behaved like salt-dependent bacteria, showing faster growth and better symbiotic performance when media were supplemented with Na or Ca salts.
Martínez, Dianny; Rodulfo, Hectorina E; Rodríguez, Lucy; Caña, Luisa E; Medina, Belkis; Guzman, Militza; Carreño, Numirin; Marcano, Daniel; De Donato, Marcos
Clinical strains of Enterobacter were isolated from Cumana's Central Hospital in Venezuela, and classified as E. cloacae (21), E. aerogenes (7), E. intermedium (1), E. sakazakii (1) and three unclassified. The strains showed high levels of resistance, especially to SXT (58.1%), CRO (48.8%), CAZ (46.6%), PIP (46.4%), CIP (45.2%) and ATM (43.3%). This is the first report for South America of blaVIM-2 in two E. cloacae and one Enterobacter sp., which also showed multiple mechanisms of resistance. Both E. cloacae showed blaTEM-1, but only one showed blaCTX-M-15 gene, while no blaSHV was detected.
Sachse, Konrad; Ruettger, Anke
Pathogenic Chlamydia (C.) psittaci and C. trachomatis strains can be genotyped based on variations in the ompA genomic locus. In the present chapter, we describe rapid genotyping assays for both chlamydial agents using the ArrayStrip™ (AS) microarray platform. The test is targeting multiple discriminatory sites in the variable domains of the ompA gene by using 35 (C. psittaci) and 61 (C. trachomatis) oligonucleotide probes representing genotype-specific polymorphisms. In addition to discrimination among the established genotypes, this approach allows identification of atypical strains that were not accessible to typing using previously established techniques, such as PCR-RFLP or serotyping. The present DNA microarray assay can be conducted directly on clinical tissue samples and is suitable for tracing epidemiological chains and exploring the dissemination of particular genotypes. The procedure is easy to handle and economically affordable, and it allows genotyping of up to 32 clinical samples per day, thus lending itself for routine diagnosis as well.
Vitale, Maria; Scatassa, Maria Luisa; Cardamone, Cinzia; Oliveri, Giuseppa; Piraino, Chiara; Alduina, Rosa; Napoli, Concetta
A case of staphylococcal food poisoning was observed in two individuals of the same family after consumption of primosale, a semiripened sheep cheese produced in Sicily. Staphylococcus aureus isolated from the cheese produced enterotoxin C (SEC) and carried both the enterotoxin C (sec) and the toxic shock syndrome toxin (tsst-1) gene. Following this case, an extensive survey was conducted on 971 food samples (raw milk, cheese, meat, and food preparations). S. aureus was detected in 102 of 971 food samples, from all types of food with the exception of ricotta cheese. The tsst-1 gene was present in 42% of the strains, either alone or in combination with other toxin genes. The enterotoxin C gene was the most represented enterotoxin, but it was only found in dairy products. Six S. aureus isolates carried the sea gene alone, two isolates carried both sea and seb, and one isolate carried both sea and sec. A significant percentage (46%) of all isolates carried a toxin gene, creating significant concern that virulent S. aureus can be transmitted through food in Sicily.
Tenover, Fred C.; Sinner, Scott W.; Segal, Robert E.; Huang, Vanthida; Alexandre, Shandline S.; McGowan, John E.; Weinstein, Melvin P.
Following an initial response to vancomycin therapy, a patient with meticillin-resistant Staphylococcus aureus (MRSA) bacteraemia developed endocarditis, failed a second course of vancomycin and then failed daptomycin therapy. An increase in the vancomycin minimum inhibitory concentrations of four consecutive MRSA blood isolates from 2 μg/mL to 8 μg/mL was shown by Etest. Population analysis of four successive blood culture isolates recovered over the 10-week period showed that the MRSA strain became progressively less susceptible to both vancomycin and daptomycin. Retrospectively, the macro Etest method using teicoplanin indicated a decrease in vancomycin susceptibility in the second blood isolate. The patient improved after treatment with various courses of trimethoprim/sulphamethoxazole, quinupristin/dalfopristin and linezolid. Early detection of vancomycin-heteroresistant S. aureus isolates, which appeared to have clinical significance in this case, continues to be a challenge for the clinical laboratory. Development of suitable practical methods for this should be given priority. Concurrent development of resistance to vancomycin and daptomycin, whilst rare, must be considered in a patient who is unresponsive to daptomycin following vancomycin therapy. PMID:19233622
Matthes, Rutger; Lührman, Anne; Holtfreter, Silva; Kolata, Julia; Radke, Dörte; Hübner, Nils-Olaf; Assadian, Ojan; Kramer, Axel
Previous studies on the antimicrobial activity of cold atmospheric pressure argon plasma showed varying effects against mecA+ or mecA-Staphylococcus aureus strains. This observation may have important clinical and epidemiological implications. Here, the antibacterial activity of argon plasma was investigated against 78 genetically different S. aureus strains, stratified by mecA, luk-P, agr1-4, or the cell wall capsule polysaccharide types 5 and 8. kINPen09® served as the plasma source for all experiments. On agar plates, mecA+luk-P-S. aureus strains showed a decreased susceptibility against plasma compared to other S. aureus strains. This study underlines the high complexity of microbial defence against antimicrobial treatment and confirms a previously reported strain-dependent susceptibility of S. aureus to plasma treatment.
Fernández, Olga; Diaz-Toro, Yira; Valderrama, Liliana; Ovalle, Clemencia; Valderrama, Mabel; Castillo, Harry; Perez, Mauricio; Saravia, Nancy Gore
Resistance to antimonial drugs has been documented in Leishmania isolates transmitted in South America, Europe, and Asia. The frequency and distribution of resistance to these and other antileishmanial drugs are unknown. Technical constraints have limited the assessment of drug susceptibility of clinical strains of Leishmania. Susceptibility of experimentally selected lines and 130 clinical strains of Leishmania panamensis, L. braziliensis, and L. guyanensis to meglumine antimoniate and miltefosine was determined on the basis of parasite burden and percentage of infected U-937 human macrophages. Reductions of infection at single predefined concentrations of meglumine antimoniate and miltefosine and 50% effective doses (ED(50)s) were measured and correlated. The effects of 34°C and 37°C incubation temperatures and different parasite-to-host cell ratios on drug susceptibility were evaluated at 5, 10, and 20 parasites/cell. Reduction of the intracellular burden of Leishmania amastigotes in U-937 cells exposed to the predefined concentrations of meglumine antimoniate or miltefosine discriminated sensitive and experimentally derived resistant Leishmania populations and was significantly correlated with ED(50) values of clinical strains (for meglumine antimoniate, ρ = -0.926 and P < 0.001; for miltefosine, ρ = -0.906 and P < 0.001). Incubation at 37°C significantly inhibited parasite growth compared to that at 34°C in the absence of antileishmanial drugs and resulted in a significantly lower ED(50) in the presence of drugs. Susceptibility assessment was not altered by the parasite-to-cell ratio over the range evaluated. In conclusion, measurement of the reduction of parasite burden at a single predetermined drug concentration under standardized conditions provides an efficient and reliable strategy for susceptibility evaluation and monitoring of clinical strains of Leishmania.
Fernández, Olga; Diaz-Toro, Yira; Valderrama, Liliana; Ovalle, Clemencia; Valderrama, Mabel; Castillo, Harry; Perez, Mauricio
Resistance to antimonial drugs has been documented in Leishmania isolates transmitted in South America, Europe, and Asia. The frequency and distribution of resistance to these and other antileishmanial drugs are unknown. Technical constraints have limited the assessment of drug susceptibility of clinical strains of Leishmania. Susceptibility of experimentally selected lines and 130 clinical strains of Leishmania panamensis, L. braziliensis, and L. guyanensis to meglumine antimoniate and miltefosine was determined on the basis of parasite burden and percentage of infected U-937 human macrophages. Reductions of infection at single predefined concentrations of meglumine antimoniate and miltefosine and 50% effective doses (ED50s) were measured and correlated. The effects of 34°C and 37°C incubation temperatures and different parasite-to-host cell ratios on drug susceptibility were evaluated at 5, 10, and 20 parasites/cell. Reduction of the intracellular burden of Leishmania amastigotes in U-937 cells exposed to the predefined concentrations of meglumine antimoniate or miltefosine discriminated sensitive and experimentally derived resistant Leishmania populations and was significantly correlated with ED50 values of clinical strains (for meglumine antimoniate, ρ = −0.926 and P < 0.001; for miltefosine, ρ = −0.906 and P < 0.001). Incubation at 37°C significantly inhibited parasite growth compared to that at 34°C in the absence of antileishmanial drugs and resulted in a significantly lower ED50 in the presence of drugs. Susceptibility assessment was not altered by the parasite-to-cell ratio over the range evaluated. In conclusion, measurement of the reduction of parasite burden at a single predetermined drug concentration under standardized conditions provides an efficient and reliable strategy for susceptibility evaluation and monitoring of clinical strains of Leishmania. PMID:22518860
Li, Xian-Hui; Yang, Chen; Guo, Li-Min; Liu, Chun-Hong; Qu, Di; Zheng, Chun-Quan
Staphylococcus aureus (S. aureus) is hard to be eradicated, not only due to the emergence of antibiotic resistant strains but also because of its ability to form biofilm. Antibiotics are the major approach to treating biofilm infections, but their effects are unsatisfactory. One of the potential alternative treatments for controlling biofilm infections is photodynamic therapy (PDT), which requires the administration of photosensitizer, followed by light activation. 5-aminolevulinic acid (ALA), a natural photosensitizer prodrug, presents favorable characteristics, such as easy penetration and rapid clearance. These advantages enable ALA-based PDT (ALA-PDT) to be well-tolerated by patients and it can be repeatedly applied without cumulative toxicity or serious side effects. ALA-PDT has been proven to be an effective treatment for multidrug resistant pathogens; however, the study of its effect on S. aureus biofilm is limited. Here, we established our PDT system based on the utilization of ALA and a light-emitting diode, and we tested the effect of ALA-PDT on S. aureus biofilm as well as the combined effect of ALA-PDT and antibiotics on S. aureus biofilm. Our results showed that ALA-PDT has a strong antibacterial effect on S. aureus biofilm, which was confirmed by the confocal laser scanning microscope. We also found that lethal photosensitization occurred predominantly in the upper layer of the biofilm, while the residual live bacteria were located in the lower layer of the biofilm. In addition, the improved bactericidal effect was observed in the combined treatment group but in a strain-dependent manner. Our results suggest that ALA-PDT is a potential alternative approach for future clinical use to treat S. aureus biofilm-associated infections, and some patients may benefit from the combined treatment of ALA-PDT and antibiotics, but drug sensitivity testing should be performed in advance. PMID:28358851
Yadav, Mukesh Kumar; Chae, Sung-Won; Im, Gi Jung; Chung, Jae-Woo; Song, Jae-Jun
Background Inhibition and eradication of Staphylococcus aureus biofilms with conventional antibiotic is difficult, and the treatment is further complicated by the rise of antibiotic resistance among staphylococci. Consequently, there is a need for novel antimicrobials that can treat biofilm-related infections and decrease antibiotics burden. Natural compounds such as eugenol with anti-microbial properties are attractive agents that could reduce the use of conventional antibiotics. In this study we evaluated the effect of eugenol on MRSA and MSSA biofilms in vitro and bacterial colonization in vivo. Methods and Results Effect of eugenol on in vitro biofilm and in vivo colonization were studied using microtiter plate assay and otitis media-rat model respectively. The architecture of in vitro biofilms and in vivo colonization of bacteria was viewed with SEM. Real-time RT-PCR was used to study gene expression. Check board method was used to study the synergistic effects of eugenol and carvacrol on established biofilms. Eugenol significantly inhibited biofilms growth of MRSA and MSSA in vitro in a concentration-dependent manner. Eugenol at MIC or 2×MIC effectively eradicated the pre-established biofilms of MRSA and MSSA clinical strains. In vivo, sub-MIC of eugenol significantly decreased 88% S. aureus colonization in rat middle ear. Eugenol was observed to damage the cell-membrane and cause a leakage of the cell contents. At sub-inhibitory concentration, it decreases the expression of biofilm-and enterotoxin-related genes. Eugenol showed a synergistic effect with carvacrol on the eradication of pre-established biofilms. Conclusion/Major Finding This study demonstrated that eugenol exhibits notable activity against MRSA and MSSA clinical strains biofilms. Eugenol inhibited biofilm formation, disrupted the cell-to-cell connections, detached the existing biofilms, and killed the bacteria in biofilms of both MRSA and MSSA with equal effectiveness. Therefore, eugenol may
Bui, Long M. G.; Hoffmann, Peter; Turnidge, John D.; Zilm, Peter S.
An undetermined feature of Staphylococcus aureus pathogenesis is its persistence and then relapse of disease. This has been explained by its switch to alternative lifestyles, mainly as biofilm or small-colony variants (SCVs). Studying the native characteristics of SCVs has been problematic due to their reversion to the parental lifestyle. We have observed that for a number of S. aureus strains as they switch to an SCV lifestyle, there is the formation of an extracellular matrix. We focused our analysis on one strain, WCH-SK2. For bacterial survival in the host, the combination of low nutrients and the prolonged time frame forms a stress that selects for a specific cell type from the population. In this context, we used steady-state growth conditions with low nutrients and a controlled low growth rate for a prolonged time and with methylglyoxal. These conditions induced S. aureus WCH-SK2 into a stable SCV cell type; the cells did not revert after subculturing. Analysis revealed these cells possessed a metabolic and surface profile that was different from those of previously described SCVs or biofilm cells. The extracellular matrix was protein and extracellular DNA but not polysaccharide. The SCV cells induced expression of certain surface proteins (such as Ebh) and synthesis of lantibiotics while downregulating factors that stimulate the immune response (leucocidin, capsule, and carotenoid). Our data reveal cell heterogeneity within an S. aureus population and under conditions that resemble long-term survival in the host have identified a previously unnoticed S. aureus cell type with a distinctive metabolic and molecular profile. PMID:25385795
Zhang, Qing-Zhao; Zhao, Ke-Qing; Wu, Yang; Li, Xian-Hui; Yang, Chen; Guo, Li-Min; Liu, Chun-Hong; Qu, Di; Zheng, Chun-Quan
Staphylococcus aureus (S. aureus) is hard to be eradicated, not only due to the emergence of antibiotic resistant strains but also because of its ability to form biofilm. Antibiotics are the major approach to treating biofilm infections, but their effects are unsatisfactory. One of the potential alternative treatments for controlling biofilm infections is photodynamic therapy (PDT), which requires the administration of photosensitizer, followed by light activation. 5-aminolevulinic acid (ALA), a natural photosensitizer prodrug, presents favorable characteristics, such as easy penetration and rapid clearance. These advantages enable ALA-based PDT (ALA-PDT) to be well-tolerated by patients and it can be repeatedly applied without cumulative toxicity or serious side effects. ALA-PDT has been proven to be an effective treatment for multidrug resistant pathogens; however, the study of its effect on S. aureus biofilm is limited. Here, we established our PDT system based on the utilization of ALA and a light-emitting diode, and we tested the effect of ALA-PDT on S. aureus biofilm as well as the combined effect of ALA-PDT and antibiotics on S. aureus biofilm. Our results showed that ALA-PDT has a strong antibacterial effect on S. aureus biofilm, which was confirmed by the confocal laser scanning microscope. We also found that lethal photosensitization occurred predominantly in the upper layer of the biofilm, while the residual live bacteria were located in the lower layer of the biofilm. In addition, the improved bactericidal effect was observed in the combined treatment group but in a strain-dependent manner. Our results suggest that ALA-PDT is a potential alternative approach for future clinical use to treat S. aureus biofilm-associated infections, and some patients may benefit from the combined treatment of ALA-PDT and antibiotics, but drug sensitivity testing should be performed in advance.
Tranchemontagne, Zachary R.; Camire, Ryan B.; O'Donnell, Vanessa J.; Baugh, Jessfor
Methicillin-resistant Staphylococcus aureus (MRSA) causes invasive, drug-resistant skin and soft tissue infections. Reports that S. aureus bacteria survive inside macrophages suggest that the intramacrophage environment may be a niche for persistent infection; however, mechanisms by which the bacteria might evade macrophage phagosomal defenses are unclear. We examined the fate of the S. aureus-containing phagosome in THP-1 macrophages by evaluating bacterial intracellular survival and phagosomal acidification and maturation and by testing the impact of phagosomal conditions on bacterial viability. Multiple strains of S. aureus survived inside macrophages, and in studies using the MRSA USA300 clone, the USA300-containing phagosome acidified rapidly and acquired the late endosome and lysosome protein LAMP1. However, fewer phagosomes containing live USA300 bacteria than those containing dead bacteria associated with the lysosomal hydrolases cathepsin D and β-glucuronidase. Inhibiting lysosomal hydrolase activity had no impact on intracellular survival of USA300 or other S. aureus strains, suggesting that S. aureus perturbs acquisition of lysosomal enzymes. We examined the impact of acidification on S. aureus intramacrophage viability and found that inhibitors of phagosomal acidification significantly impaired USA300 intracellular survival. Inhibition of macrophage phagosomal acidification resulted in a 30-fold reduction in USA300 expression of the staphylococcal virulence regulator agr but had little effect on expression of sarA, saeR, or sigB. Bacterial exposure to acidic pH in vitro increased agr expression. Together, these results suggest that S. aureus survives inside macrophages by perturbing normal phagolysosome formation and that USA300 may sense phagosomal conditions and upregulate expression of a key virulence regulator that enables its intracellular survival. PMID:26502911
Wei, Wei; Luo, Xia; Zheng, Linyong; Yu, Mengyao; Jiang, Nan; Xu, Xiao-yan; Yang, Zhi-rong
A Morchella spp. strain was isolated from a wild morel mushroom, and the effects of its mycelia extract on the ethanol-induced gastric mucosal lesions of rats were investigated in vivo. Sequence analysis of internal transcribed spacer suggested that this Morchella spp. strain (strain No. M1) was clustered together with M. conica in the phylogenetic tree. The superoxide dismutase (SOD) activity increased significantly compared to the control. However, the malondialdehyde (MDA) level and myeloperoxidase (MPO) activity decreased significantly compared to the control. These results indicated that M1 is one member of M. conica and the protective effects of M1 extract against the ethanol-induced gastric lesions may be related to the increased SOD activity and decreased MDA level and MPO activity in rats.
Miranda, J M; Guarddon, M; Mondragon, A; Vázquez, B I; Fente, C A; Cepeda, A; Franco, C M
The mean counts of Enterococcus spp. were determined for 30 samples each of organic chicken meat, conventional chicken meat, and turkey meat, and differences for Enterococcus contamination in meat were determined. Two enterococci strains from each sample were isolated to obtain a total of 180 strains, and resistance to ampicillin, chloramphenicol, doxycycline, ciprofloxacin, erythromycin, gentamicin, nitrofurantoin, and vancomycin was determined by a disk diffusion method. Average counts obtained showed that Enterococcus mean counts from organic chicken meat (3.18 log CFU/g) were significantly higher than those obtained from conventional chicken meat (2.06 log CFU/g) or conventional turkey meat (1.23 log CFU/g). However, the resistance data obtained showed that isolates from organic chicken meat were less resistant than enterococci isolates from conventional chicken meat to ampicillin (P = 0.0067), chloramphenicol (P = 0.0154), doxycycline (P = 0.0277), ciprofloxacin (P = 0.0024), erythromycin (P = 0.0028), and vancomycin (P = 0.0241). In addition, isolates from organic chicken were less resistant than conventional turkey meat isolates to ciprofloxacin (P = 0.001) and erythromycin (P = 0.0137). Multidrug-resistant isolates were found in every group tested, but rates of multidrug-resistant strains were significantly higher in conventional chicken and turkey than those obtained from organic chicken meat. Enterococcus faecalis was the most common species isolated from organic chicken (36.67%), whereas Enterococcus durans was the most common species isolated from conventional chicken (58.33%) and turkey (56.67%). The rates obtained for antimicrobial resistance suggest that although organic chicken meat may have higher numbers of Enterococcus, these bacteria present a lower level of antimicrobial resistance.
Mukherjee, Arghya; Chettri, Bobby; Langpoklakpam, James S; Singh, Arvind K; Chattopadhyay, Dhrubajyoti
Here, we report the 2.6 Mb draft genome sequence of hydrocarbon-degrading Staphylococcus saprophyticus strain CNV2, isolated from oil-contaminated soil in Guwahati, India. CNV2 contains 2,545 coding sequences and has a G+C content of 33.2%. This is the first report of the genome sequence of an S. saprophyticus adapted to an oil-contaminated environment.
Zhang, Xia; Xu, Xiaomeng; Yuan, Wenchang; Hu, Qiwen; Shang, Weilong; Hu, Xiaomei
ST239-MRSA-SCCmec III (ST239, sequence type 239; MRSA, methicillin-resistant Staphylococcus aureus; SCCmec III, staphylococcal cassette chromosome mec type III) is the most predominant clone of hospital-acquired methicillin-resistant S. aureus in mainland China. We report here the complete genome sequence of XN108, the first vancomycin-intermediate S. aureus strain isolated from a steam-burned patient with a wound infection. PMID:25059856
Simor, Andrew E; Louie, Lisa; Watt, Christine; Gravel, Denise; Mulvey, Michael R; Campbell, Jennifer; McGeer, Allison; Bryce, Elizabeth; Loeb, Mark; Matlow, Anne
We determined the in vitro antimicrobial susceptibilities of 7,942 methicillin-resistant Staphylococcus aureus (MRSA) isolates obtained from patients hospitalized in 48 Canadian hospitals from 1995 to 2008. Regional variations in susceptibilities were identified. The dissemination of community-associated strains in Canada appears to have contributed to increased susceptibility of MRSA to several non-beta-lactam antimicrobial agents in the past decade. Reduced susceptibility to glycopeptides was not identified.
Várady, M; Praslicka, J; Corba, J
A multiple resistant field strain of gastro-intestinal nematodes was detected in Cashmere and Angora goats imported from New Zealand. Different treatments with three types of broad spectrum anthelmintics (albendazole, levamisole/tetramisole and ivermectin) at various dose rates are described. Satisfactory effect in Angora goats was not achieved until all three anthelmintics were administered simultaneously at twice the normal sheep dose. Post mortem worm counts and identification revealed that the resistant population consisted of 89% Ostertagia circumcincta, 6% Ostertagia ostertagi and 5% Ostertagia trifurcata. However, egg hatch assay carried out seven months later detected the presence of resistant nematodes again.
Luong, Thanh T; Sau, Keya; Roux, Christelle; Sau, Subrata; Dunman, Paul M; Lee, Chia Y
ClpC is an ATPase chaperone found in most Gram-positive low-GC bacteria. It has been recently reported that ClpC affected virulence gene expression in Staphylococcus aureus. Here we report that ClpC regulates transcription of the cap operon and accumulation of capsule, a major virulence factor for S. aureus. As virulence genes are regulated by a complex regulatory network in S. aureus, we have used capsule as a model to understand this regulation. By microarray analyses of strain Newman, we found that ClpC strongly activates transcription of the sae operon, whose products are known to negatively regulate capsule synthesis in this strain. Further studies indicated that ClpC repressed capsule production by activating the sae operon in strain Newman. Interestingly, the clpC gene cloned into a multiple-copy plasmid vector exhibited an activation phenotype, suggesting that ClpC overexpression has a net positive effect. In the absence of sae function, by either deletion or correction of a native mutation within saeS, we found that ClpC had a positive effect on capsule production. Indeed, in the UAMS-1 strain, which does not have the saeS mutation, ClpC functioned as an activator of capsule production. Our microarray analyses of strain Newman also revealed that CodY, a repressor of capsule production, was repressed by ClpC. Using genetic approaches, we showed that CodY functioned downstream of ClpC, leading to capsule activation both in Newman and in UAMS-1. Thus, ClpC functions in two opposite pathways in capsule regulation in strain Newman but functions as a positive activator in strain UAMS-1.
Łysakowska, Monika E; Sienkiewicz, Monika; Banaszek, Katarzyna; Sokołowski, Jerzy
Enterococci are able to survive endodontic procedures and contribute to the failure of endodontic therapy. Thus, it is essential to identify novel ways of eradicating them from infected root canals. One such approach may be the use of antimicrobials such as plant essential oils. Enterococcal strains were isolated from endodontically treated teeth by standard microbiological methods. Susceptibility to antibiotics was evaluated by the disc-diffusion method. The minimal inhibitory concentration (MIC) of geranium essential oil was investigated by microdilution in 96-well microplates in Mueller Hinton Broth II. Biofilm eradication concentrations were checked in dentin tests. Geranium essential oil inhibited enterococcal strains at concentrations ranging from 1.8-4.5 mg/mL. No correlation was shown between resistance to antibiotics and the MICs of the test antimicrobials. The MICs of the test oil were lower than those found to show cytotoxic effects on the HMEC-1 cell line. Geranium essential oil eradicated enterococcal biofilm at concentrations of 150 mg/mL. Geranium essential oil inhibits the growth of endodontic enterococcal species at lower concentrations than those required to reach IC50 against the HMEC-1 cell line, and is effective against bacteria protected in biofilm at higher concentrations. In addition, bacteria do not develop resistance to essential oils. Hence, geranium essential oil represents a possible alternative to other antimicrobials during endodontic procedures.
Beattie, S H; Williams, A G
An improved qualitative cell cytotoxicity assay for the detection of Bacillus cereus emetic and enterotoxin is described. The presence of toxin in culture supernatant fluids was detected by measurement with the tetrazolium salt MTT, as it adversely affects the metabolic status of cultured CHO cells. Psychrotrophic B. cereus isolates (65) were assessed for toxin production using the cytotoxicity assay, and 91% of culture supernatant fluids were cytotoxic. Toxin assessment using BCET-RPLA and ELISA immunoassays indicated that 51% and 85% of the cultures, respectively, were toxigenic. There were pronounced strain differences in the amount of toxin produced by the B. cereus isolates. Some isolates of B. circulans, B. laterosporus/cereus, B. lentus, B. licheniformis, B. mycoides, B. subtilis and B. thuringiensis were also toxigenic.
Nowakiewicz, Aneta; Ziółkowska, Grażyna; Zięba, Przemysław; Gnat, Sebastian; Wojtanowicz-Markiewicz, Katarzyna; Trościańczyk, Aleksandra
The aim of the study was molecular analysis of coagulase-positive isolates of Staphylococcus bacteria obtained from wild animals and evaluation of their resistance to antimicrobial agents. A total of 76 rectal swabs were taken from wild animals. The species of the Staphylococcus isolates was determined by MALDI TOF MS, susceptibility to antimicrobials was evaluated by phenotypic and molecular methods, epidemiological analysis (ADSRRS-fingerprinting) was also carried out. MRSA isolate was typed by MLST and spa-typing. The animals tested, were carriers (n=38) of coagulase-positive Staphylococcus (S. aureus, S. pseudintermedius and S. delphini B). Analyzed isolates were resistant to 1 or 2 antimicrobials, which was confirmed by the presence of genes (blaZ, ermA, ermB, msrA, tetK and tetM). A multi-drug resistant and methicillin-resistant isolate of S. aureus was obtained as well (MRSA, ST8, t1635, PVL-positive and ACME-negative). The ADSRRS-fingerprinting method enabled interspecific and intraspecific differentiation of coagulase-positive Staphylococcus isolates, revealing a certain degree of correlation between the species of the isolate, and the degree of similarity between the isolates. The presence of resistance genes in 13% (5/38) of the isolates obtained from wild animals, including one methicillin-resistant isolate, is relatively small in comparison to the degree of colonization by resistant strains in humans, livestock or pets. Nevertheless, due to the possibility of contact between wild animals, domestic animals and humans, transmission of resistant strains is possible, as suggested by our isolation of a MRSA strain typed as ST8 and specific spa type t1635, which had previously been isolated exclusively from humans.
Dağı, Hatice Türk; Fındık, Duygu; Demirel, Gamze; Arslan, Uğur
Background: Staphylococus aureus can be found as a commensal on skin and nasal flora or it may cause local and invasive infections. S. aureus has a large number of virulence factors. Aims: To investigate the methicillin resistance and frequency of various virulence factors in S. aureus nasal isolates. Study Design: Descriptive study. Methods: Nasal samples collected from university students were cultured in media. S. aureus was identified by conventional methods and the Staphyloslide latex test (Becton Dickinson, Sparks, USA). Antibiotic susceptibility tests were conducted, and the methicillin resistance was determined. The mecA, nuc, pvl and staphylococcal toxin genes were examined by polymerase chain reaction (PCR). Results: S. aureus was isolated in 104 of 600 (17.3%) nasal samples. In total, 101 (97.1%) S. aureus isolates were methicillin-sensitive and the remaining 3 (2.9%) were methicillin-resistant. Furthermore, all but five isolates carried at least one staphylococcal enterotoxin gene, with seg being predominant. The tst and eta genes were determined in 29 (27.9%), and 3 (2.9%) isolates, respectively. None of the S. aureus isolates harbored see, etb, and pvl genes. Conclusion: A moderate rate of S. aureus carriage and low frequency of MRSA were detected in healthy students. S. aureus isolates had a high prevalence of staphylococcal enterotoxin genes and the tst gene. In this study, a large number of virulence factors were examined in S. aureus nasal isolates, and the data obtained from this study can be used for monitoring the prevalence of virulence genes in S. aureus strains isolated from nasal carriers. PMID:26167341
Majcherczyk, Paul A; McKenna, Therese; Moreillon, Philippe; Vaudaux, Pierre
To explore the discriminatory power of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for detecting subtle differences in isogenic isolates, we tested isogenic strains of Staphylococcus aureus differing in their expression of resistance to methicillin or teicoplanin. More important changes in MALDI-TOF MS spectra were found with strains differing in methicillin than in teicoplanin resistance. In comparison, very minor or no changes were recorded in pulsed-field gel electrophoresis profiles or peptidoglycan muropeptide digest patterns of these strains, respectively. MALDI-TOF MS might be useful to detect subtle strain-specific differences in ionizable components released from bacterial surfaces and not from their peptidoglycan network.
Thirumala, M; Reddy, Sultanpuram Vishnuvardhan; Mahmood, S K
The present study reports two bacteria, designated 87I and 112A, which were isolated from soil and activated sludge samples from Hyderabad, India, and that are capable of producing poly-3-hydroxybutyrate (PHB). Based on phenotypical features and genotypic investigations, these microorganisms were identified as Bacillus spp. Their optimal growth occurred between 28 degrees C and 30 degrees C and pH 7. Bacillus sp. 87I yielded a maximum of 70.04% dry cell weight (DCW) PHB in medium containing glucose as carbon source, followed by 55.5% DCW PHB in lactose-containing medium, whereas Bacillus sp. 112A produced a maximum of 67.73% PHB from glucose, 58.5% PHB from sucrose, followed by 50.5% PHB from starch as carbon substrates. The viscosity average molecular mass (M (v)) of the polymers from Bacillus sp. 87I was 513 kDa and from Bacillus sp. 112A was 521 kDa. All the properties of the biopolymers produced by the two strains 87I and 112A were characterized.
Hajlaoui, Hafedh; Mighri, Hedi; Noumi, Emira; Snoussi, Mejdi; Trabelsi, Najla; Ksouri, Riadh; Bakhrouf, Amina
Essential oil extracted by hydrodistillation from Tunisian variety of Cuminumcyminum was characterized by means of GC and GC-MS. Twenty-one components were identified and C. cyminum contained cuminlaldehyde (39.48%), gamma-terpinene (15.21%), O-cymene (11.82%), beta-pinene (11.13%), 2-caren-10-al (7.93%), trans-carveol (4.49%) and myrtenal (3.5%) as a major components. Moreover, C. cyminum oil exhibited higher antibacterial and antifungal activities with a high effectiveness against Vibrio spp. strains with a diameter of inhibition zones growth ranging from 11 to 23 mm and MIC and MBC values ranging from (0.078-0.31 mg/ml) to (0.31-1.25mg/ml), respectively. On the other hand, the cumin oil was investigated for its antioxidant activities using four different tests then compared with BHT. Results showed that cumin oil exhibit a higher activity in each antioxidant system with a special attention for beta-carotene bleaching test (IC(50): 20 microg/ml) and reducing power (EC(50): 11 microg/ml). In the light of these findings, we suggested that C. cyminum essential oil may be considered as an interesting source of antibacterial, antifungal and antioxidants components used as potent agents in food preservation and for therapeutic or nutraceutical industries.
Ansari, Mohammad Azam; Khan, Haris M.; Khan, Aijaz A.; Pal, Ruchita; Cameotra, Swaranjit Singh
To date very little studies are available in the literature on the interaction of Al2O3 nanoparticles with multidrug-resistant strains of Staphylococcus aureus. Considering the paucity of earlier reports the objective of present study was to investigate the antibacterial activity of Al2O3 NPs (<50 nm) against methicillin-resistant S. aureus and methicillin-resistant coagulase negative staphylococci by various methods. Al2O3 NPs were characterized by scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray diffraction. The MIC was found to be in the range of 1,700-3,400 μg/ml. Almost no growth was observed at 2,000 μg/ml for up to 10 h. SEM micrograph revealed that the treated cells were significantly damaged, showed indentation on cell surface and clusters of NPs on bacterial cell wall. HR-TEM micrograph shows disruption and disorganization of cell membrane and cell wall. The cell membrane was extensively damaged and, most probably, the intracellular content has leaked out. Al2O3 NPs not only adhered at the surface of cell membrane, but also penetrated inside the bacterial cells, cause formation of irregular-shaped pits and perforation on their surfaces and may also interact with the cellular macromolecules causing adverse effect including cell death. The data presented here are novel in that Al2O3 NPs are effective bactericidal agents regardless of the drug resistance mechanisms that confer importance to these bacteria as an emergent pathogen. Therefore, in depth studies regarding the interaction of Al2O3 NPs with cells, tissues, and organs as well as the optimum dose required to produce therapeutic effects need to be ascertained before we can expect a more meaningful role of the Al2O3 NPs in medical application.
Ou, Judy J. J.; Drilling, Amanda J.; Cooksley, Clare; Bassiouni, Ahmed; Kidd, Stephen P.; Psaltis, Alkis J.; Wormald, Peter J.; Vreugde, Sarah
Background: Staphylococcus aureus (S. aureus) small colony variants (SCVs) can survive within the host intracellular milieu and are associated with chronic relapsing infections. However, it is unknown whether host invasion rates and immune responses differ between SCVs and their wild-type counterparts. This study used a stable S. aureus SCV (WCH-SK2SCV) developed from a clinical isolate (WCH-SK2WT) in inflammation-relevant conditions. Intracellular infection rates as well as host immune responses to WCH-SK2WT and WCH-SK2SCV infections were investigated. Method: NuLi-1 cells were infected with either WCH-SK2WT or WCH-SK2SCV, and the intracellular infection rate was determined over time. mRNA expression of cells infected with each strain intra- and extra-cellularly was analyzed using a microfluidic qPCR array to generate an expression profile of thirty-nine genes involved in the host immune response. Results: No difference was found in the intracellular infection rate between WCH-SK2WT and WCH-SK2SCV. Whereas, extracellular infection induced a robust pro-inflammatory response, intracellular infection elicited a modest response. Intracellular WCH-SK2WT infection induced mRNA expression of TLR2, pro-inflammatory cytokines (IL1B, IL6, and IL12) and tissue remodeling factors (MMP9). In contrast, intracellular WCH-SK2SCV infection induced up regulation of only TLR2. Conclusions: Whereas, host intracellular infection rates of WCH-SK2SCV and WCH-SK2WT were similar, WCH-SK2SCV intracellular infection induced a less widespread up regulation of pro-inflammatory and tissue remodeling factors in comparison to intracellular WCH-SK2WT infection. These findings support the current view that SCVs are able to evade host immune detection to allow their own survival. PMID:28083514
Ou, Judy J J; Drilling, Amanda J; Cooksley, Clare; Bassiouni, Ahmed; Kidd, Stephen P; Psaltis, Alkis J; Wormald, Peter J; Vreugde, Sarah
Background:Staphylococcus aureus (S. aureus) small colony variants (SCVs) can survive within the host intracellular milieu and are associated with chronic relapsing infections. However, it is unknown whether host invasion rates and immune responses differ between SCVs and their wild-type counterparts. This study used a stable S. aureus SCV (WCH-SK2(SCV)) developed from a clinical isolate (WCH-SK2(WT)) in inflammation-relevant conditions. Intracellular infection rates as well as host immune responses to WCH-SK2(WT) and WCH-SK2(SCV) infections were investigated. Method: NuLi-1 cells were infected with either WCH-SK2(WT) or WCH-SK2(SCV), and the intracellular infection rate was determined over time. mRNA expression of cells infected with each strain intra- and extra-cellularly was analyzed using a microfluidic qPCR array to generate an expression profile of thirty-nine genes involved in the host immune response. Results: No difference was found in the intracellular infection rate between WCH-SK2(WT) and WCH-SK2(SCV). Whereas, extracellular infection induced a robust pro-inflammatory response, intracellular infection elicited a modest response. Intracellular WCH-SK2(WT) infection induced mRNA expression of TLR2, pro-inflammatory cytokines (IL1B, IL6, and IL12) and tissue remodeling factors (MMP9). In contrast, intracellular WCH-SK2(SCV) infection induced up regulation of only TLR2. Conclusions: Whereas, host intracellular infection rates of WCH-SK2(SCV) and WCH-SK2(WT) were similar, WCH-SK2(SCV) intracellular infection induced a less widespread up regulation of pro-inflammatory and tissue remodeling factors in comparison to intracellular WCH-SK2(WT) infection. These findings support the current view that SCVs are able to evade host immune detection to allow their own survival.
Szczuka, Ewa; Makowska, Nicoletta; Bosacka, Karolina; Słotwińska, Anna; Kaznowski, Adam
Coagulase-negative staphylococci (CoNS) are the most frequently isolated bacteria from the blood and the predominant cause of nosocomial infections. Macrolides, lincosamides and streptogramin B (MLSB) antibiotics, especially erythromycin and clindamycin, are important therapeutic agents in the treatment of methicillin-resistant staphylococci infections. Among CoNS, Staphylococcus hominis represents the third most common organism. In spite of its clinical significance, very little is known about its mechanisms of resistance to antibiotics, especially MLSB. Fifty-five S. hominis isolates from the blood and the surgical wounds of hospitalized patients were studied. The erm(C) gene was predominant in erythromycin-resistant S. hominis isolates. The methylase genes, erm(A) and erm(B), were present in 15 and 25% of clinical isolates, respectively. A combination of various erythromycin resistance methylase (erm) genes was detected in 15% S. hominis isolates. The efflux gene msr(A) was detected in 18% of isolates, alone in four isolates, and in different combinations in a further six. The lnu(A) gene, responsible for enzymatic inactivation of lincosamides was carried by 31% of the isolates. No erythromycin resistance that could not be attributed to the genes erm(A), erm(B), erm(C) and msr(A) was detected. In S. hominis, 75 and 84%, respectively, were erythromycin resistant and clindamycin susceptible. Among erythromycin-resistant S. hominis isolates, 68% of these strains showed the inducible MLSB phenotype. Four isolates harbouring the msr(A) genes alone displayed the MSB phenotype. These studies indicated that resistance to MLSB in S. hominis is mostly based on the ribosomal target modification mechanism mediated by erm genes, mainly the erm(C), and enzymatic drug inactivation mediated by lnu(A).
Granada, Camille E; Strochein, Marcos; Vargas, Luciano K; Bruxel, Manuela; de Sá, Enilson Luiz Saccol; Passaglia, Luciane M P
This work aimed to evaluate the symbiotic compatibility and nodulation efficiency of rhizobia isolated from Desmodium incanum, Lotus corniculatus, L. subbiflorus, L. uliginosus and L. glaber plants by cross-inoculation. Twelve reference strains and 21 native isolates of rhizobia were genetically analyzed by the BOX-PCR technique, which showed a high genetic diversity among the rhizobia studied. The isolates were also characterized based on their production of indolic compounds and siderophores, as well as on their tolerance to salinity. Fifteen of the 33 rhizobia analyzed were able to produce indolic compounds, whereas 13 produced siderophores. All the tested rhizobia were sensitive to high salinity, although some were able to grow in solutions of up to 2% NaCl. Most of the native rhizobia isolated from L. uliginosus were able to induce nodulation in all plant species studied. In a greenhouse experiment using both D. incanum and L. corniculatus plants, the rhizobia isolate UFRGS Lu2 promoted the greatest plant growth. The results demonstrate that there are native rhizobia in the soils of southern Brazil that have low host specificity and are able to induce nodulation and form active nodules in several plant species.
Granada, Camille E.; Strochein, Marcos; Vargas, Luciano K.; Bruxel, Manuela; de Sá, Enilson Luiz Saccol; Passaglia, Luciane M.P.
This work aimed to evaluate the symbiotic compatibility and nodulation efficiency of rhizobia isolated from Desmodium incanum, Lotus corniculatus, L. subbiflorus, L. uliginosus and L. glaber plants by cross-inoculation. Twelve reference strains and 21 native isolates of rhizobia were genetically analyzed by the BOX-PCR technique, which showed a high genetic diversity among the rhizobia studied. The isolates were also characterized based on their production of indolic compounds and siderophores, as well as on their tolerance to salinity. Fifteen of the 33 rhizobia analyzed were able to produce indolic compounds, whereas 13 produced siderophores. All the tested rhizobia were sensitive to high salinity, although some were able to grow in solutions of up to 2% NaCl. Most of the native rhizobia isolated from L. uliginosus were able to induce nodulation in all plant species studied. In a greenhouse experiment using both D. incanum and L. corniculatus plants, the rhizobia isolate UFRGS Lu2 promoted the greatest plant growth. The results demonstrate that there are native rhizobia in the soils of southern Brazil that have low host specificity and are able to induce nodulation and form active nodules in several plant species. PMID:25071405
Zhu, Liangquan; Feng, Yu; Zhang, Ge; Jiang, Hui; Zhang, Zhen; Wang, Nan; Ding, Jiabo; Suo, Xun
Brucellosis is a wide spread zoonotic disease that causes abortion and infertility in mammals and leads to debilitating, febrile illness in humans. Brucella abortus, Brucella melitensis and Brucella suis are the major pathogenic species to humans. Vaccination with live attenuated B. suis strain 2 (S2) vaccine is an essential and critical component in the control of brucellosis in China. The S2 vaccine is very effective in preventing brucellosis in goats, sheep, cattle and swine. However, there are still debates outside of China whether the S2 vaccine is able to provide protection against heterologous virulent Brucella species. We investigated the residual virulence, immunogenicity and protective efficacy of the S2 vaccine in BALB/c mice by determining bacteria persistence in spleen, serum antibody response, cellular immune response and protection against a heterologous virulent challenge. The S2 vaccine was of low virulence as there were no bacteria recovered in spleen four weeks post vaccination. The vaccinated mice developed Brucella-specific IgG in 2-3 weeks, and a burst production of IFN-γ at one week as well as a two-fold increase in TNF-α production. The S2 vaccine protected mice from a virulent challenge by B. melitensis M28, B. abortus 2308 and B. suis S1330, and the S2 vaccinated mice did not develop any clinical signs or tissue damage. Our study demonstrated that the S2 vaccine is of low virulence, stimulates good humoral and cellular immunity and protects animals against infection by heterologous, virulent Brucella species.
Bardiau, Marjorie; Caplin, Jonathan; Detilleux, Johann; Graber, Hans; Moroni, Paolo; Taminiau, Bernard; Mainil, Jacques G
Staphylococcus (S.) aureus is recognised worldwide as an important pathogen causing contagious acute and chronic bovine mastitis. Chronic mastitis account for a significant part of all bovine cases and represent an important economic problem for dairy producers. Several properties (biofilm formation, intracellular survival, capsular expression and group agr) are thought to be associated with this chronic status. In a previous study, we found the existence of two groups of strains based on the association of these features. The aim of the present work was to confirm on a large international and non-related collection of strains the existence of these clusters and to associate them with case history records. In addition, the genomes of eight strains were sequenced to study the genomic differences between strains of each cluster. The results confirmed the existence of both groups based on capsular typing, intracellular survival and agr-typing: strains cap8-positive, belonging to agr group II, showing a low invasion rate and strains cap5-positive, belonging to agr group I, showing a high invasion rate. None of the two clusters were associated with the chronic status of the cow. When comparing the genomes of strains belonging to both clusters, the genes specific to the group "cap5-agrI" would suggest that these strains are better adapted to live in hostile environment. The existence of these two groups is highly important as they may represent two clusters that are adapted differently to the host and/or the surrounding environment.
Locke, Jeffrey B; Finn, John; Hilgers, Mark; Morales, Gracia; Rahawi, Shahad; G C, Kedar; Picazo, Juan José; Im, Weonbin; Shaw, Karen Joy; Stein, Jeffrey L
Staphylococcal resistance to linezolid (LZD) is mediated through ribosomal mutations (23S rRNA or ribosomal proteins L3 and L4) or through methylation of 23S rRNA by the horizontally transferred Cfr methyltransferase. To investigate the structural basis for oxazolidinone activity against LZD-resistant (LZD(r)) strains, we compared structurally diverse, clinically relevant oxazolidinones, including LZD, radezolid (RX-1741), TR-700 (torezolid), and a set of TR-700 analogs (including novel CD-rings and various A-ring C-5 substituents), against a panel of laboratory-derived and clinical LZD(r) Staphylococcus aureus strains possessing a variety of resistance mechanisms. Potency against all strains was correlated with optimization of C- and D-rings, which interact with more highly conserved regions of the peptidyl transferase center binding site. Activity against cfr strains was retained with either hydroxymethyl or 1,2,3-triazole C-5 groups but was reduced by 2- to 8-fold in compounds with acetamide substituents. LZD, which possesses a C-5 acetamide group and lacks a D-ring substituent, demonstrated the lowest potency against all strains tested, particularly against cfr strains. These data reveal key features contributing to oxazolidinone activity and highlight structural tradeoffs between potency against susceptible strains and potency against strains with various resistance mechanisms.
Mohajeri, Parviz; Azizkhani, Samira; Farahani, Abbas; Norozi, Baharak
Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterial pathogen frequently isolated in both hospital and community environments. Methicillin-resistant Staphylococcus aureus is considered a major nosocomial pathogen that causes severe morbidity and mortality. Objectives: The main objective of this study was to determine the genotypes of MRSA strains isolated from the nares of hospitalized and community patients in Kermanshah Hospital, western Iran, by PCR-restriction fragment length polymorphism (PCR-RFLP). Materials and Methods: Of 1387 patients, 1217 patients were screened for more than 48 hours after admission in hospital wards and 170 patients were screened in the hemodialysis unit of Kermanshah Hospital, which is the largest hospital in western Iran. S. aureus was identified by standard biochemical tests, including colonial morphology, production of coagulase, and DNase and the API20 Staph test. Methicillin-resistant Staphylococcus aureus was identified by the Oxacillin strip test. Results: In total, 258 S. aureus isolates were recovered from 1387 samples, of which 96 isolates were MRSA, 82 were hospital acquired, and 14 were community acquired. Digestion of the aro A gene revealed only one distinctive RFLP pattern in the 258 isolates. Conclusions: Methicillin-resistant Staphylococcus aureus is an increasingly common cause of nosocomial infections. Our results are in agreement with those of other studies reporting that a few specialized clones are responsible for most cases of MRSA nasal carriage. In this study, MRSA strains isolated from different wards of hospital were closely related when analyzed by coagulase gene typing. Identifying patients colonized with MRSA during hospitalization and rapidly typing them with these methods may facilitate detection of outbreaks and prevention of the spread of organisms in hospitals. PMID:27099680
Rall, V L M; Miranda, E S; Castilho, I G; Camargo, C H; Langoni, H; Guimarães, F F; Araújo Júnior, J P; Fernandes Júnior, A
The objectives of this study were to determine the occurrence and diversity of Staphylococcus spp. in milk from healthy cows and cows with subclinical mastitis in Brazil and to examine the profile of enterotoxin genes and some enterotoxins produced by Staphylococcus spp. A total of 280 individual mammary quarter milk samples from 70 healthy cows and 292 samples from 73 cows with subclinical mastitis were collected from 11 farms in the state of São Paulo, Brazil. Staphylococcus spp. were recovered from 63 (22.5%) samples from healthy cows and from 80 samples (27.4%) from cows with mastitis. The presence of Staphylococcus aureus was significantly different between these 2 groups and was more prevalent in the cows with mastitis. The presence of Staphylococcus saprophyticus was also significantly different between these 2 groups, but this organism was more prevalent in healthy cows. No statistically significant differences were observed in the numbers of other staphylococci in milk samples from the 2 groups. The sea gene was the most prevalent enterotoxin gene in both groups. Eight of 15 (53.3%) Staph. aureus carried this gene and all produced the SEA toxin. In the coagulase-negative staphylococci (CNS) group, 61 of 128 (47.5%) had the same gene and just 1 (1.6%) Staphylococcus epidermidis strain produced the enterotoxin in vitro. Because CNS were isolated from both groups of cows and most CNS contained enterotoxin genes but did not produce toxins, the role of CNS in mastitis should be carefully defined.
Zhao, Chunjiang; Xiao, Di; Zhang, Jianzhong; Zhang, Feifei; Chen, Minjun; Wang, Hui
Heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) is associated with clinical treatment failure. However, the resistance mechanism of hVISA has not been fully clarified. In the present study, comparative proteomics analysis of two pairs of isogenic vancomycin-susceptible S. aureus (VSSA) and hVISA strains isolated from two patients identified five differentially expressed proteins, IsaA, MsrA2, Asp23, GpmA, and AhpC, present in both isolate pairs. All the proteins were up-regulated in the hVISA strains. These proteins were analyzed in six pairs of isogenic VSSA and hVISA strains, and unrelated VSSA (n = 30) and hVISA (n = 24) by real-time quantitative reverse transcriptase–PCR (qRT–PCR). Of the six pairs of isogenic strains, isaA, msrA2 and ahpC were up-regulated in all six hVISA strains; whereas asp23 and gpmA were up-regulated in five hVISA strains compared with the VSSA parental strains. In the unrelated strains, statistical analyses showed that only isaA was significantly up-regulated in the hVISA strains. Analysis of the five differentially expressed proteins in 15 pairs of persistent VSSA strains by qRT–PCR showed no differences in the expression of the five genes among the persistent strains, suggesting that these genes are not associated with persistence infection. Our results indicate that increased expression of isaA may be related to hVISA resistance. PMID:23840544
Severin, Juliëtte A; Lestari, Endang Sri; Kuntaman, Kuntaman; Melles, Damian C; Pastink, Martijn; Peeters, Justine K; Snijders, Susan V; Hadi, Usman; Duerink, D Offra; van Belkum, Alex; Verbrugh, Henri A
Few data on the molecular characteristics and epidemiology of Staphylococcus aureus from Indonesia are available. The purpose of the present study was to define S. aureus reservoirs in both the Indonesian community and hospital using a collection of 329 nasal carriage isolates obtained during a survey of 3,995 healthy individuals and patients from Java, Indonesia. Only one strain (0.3%) was identified as methicillin-resistant S. aureus by mecA gene PCR. The Panton-Valentine leukocidin (PVL) genes were detected in 35 methicillin-sensitive S. aureus strains (10.6%). Molecular typing by pulsed-field gel electrophoresis of the 329 isolates showed extensive genetic diversity among both PVL-positive and PVL-negative strains. In Surabaya, Indonesia, however, a cluster was identified that was strongly associated with the presence of the PVL locus (P < 0.0001). As determined by high-throughput amplified fragment length polymorphism, PVL-positive strains occurred throughout all major AFLP clusters (I to IV). Multilocus sequence typing of a subset of isolates showed that most PVL-positive strains belonged to sequence type (ST) 188, while most PVL-negative isolates belonged to ST45. The high prevalence of PVL-positive S. aureus strains in certain regions of Indonesia is of concern since these strains may cause severe infections in the community and in hospitals.
Tasara, T; Cernela, N; Stephan, R
Molecular based approaches have gained increasing importance in routine mastitis diagnostics for typing and antibiotic resistance testing of Staphylococcus aureus. Out of 78 S. aureus strains isolated from bovine mastitis milk 10 of them harbored blaZ, blaI and blaR genes. Although 5 strains were phenotypically resistant to penicillin, the other 5 (all belonging the clonal complex 8) were penicillin susceptible. PCR amplification confirmed the presence of the blaZ, blaR and blaI genes in all 5 strains. Sequencing of these genes uncovered a 29 base deletion within the blaZ gene in all these strains that causes a translational frame shift, which is predicted to induce abrogation of BlaZ expression. Additionally single nucleotide insertions and deletions were detected in blaR of 3 strains. These insertions cause translation reading frame shifts and premature stop codons that are predicted to induce expression of truncated BlaR proteins. Using the genetically altered blaZ genes detected as targets, a real-time PCR system for detecting CC8 associated blaZ positive S. aureus strains that still remain susceptible to penicillin was developed. Such strains are part of detection challenges that must be considered in routine application of genotypic resistance testing of bovine mastitis S. aureus.
Strobel, M; Pförtner, H; Tuchscherr, L; Völker, U; Schmidt, F; Kramko, N; Schnittler, H-J; Fraunholz, M J; Löffler, B; Peters, G; Niemann, S
Host cell invasion is a major feature of Staphylococcus aureus and contributes to infection development. The intracellular metabolically active bacteria can induce host cell activation and death but they can also persist for long time periods. In this study a comparative analysis was performed of different well-characterized S. aureus strains in their interaction with a variety of host cell types. Staphylococcus aureus (strains 6850, USA300, LS1, SH1000, Cowan1) invasion was compared in different human cell types (epithelial and endothelial cells, keratinocytes, fibroblasts, osteoblasts). The number of intracellular bacteria was determined, cell inflammation was investigated, as well as cell death and phagosomal escape of bacteria. To explain strain-dependent differences in the secretome, a proteomic approach was used. Barrier cells took up high amounts of bacteria and were killed by aggressive strains. These strains expressed high levels of toxins, and possessed the ability to escape from phagolysosomes. Osteoblasts and keratinocytes ingested less bacteria, and were not killed, even though the primary osteoblasts were strongly activated by S. aureus. In all cell types S. aureus was able to persist. Strong differences in uptake, cytotoxicity, and inflammatory response were observed between primary cells and their corresponding cell lines, demonstrating that cell lines reflect only partially the functions and physiology of primary cells. This study provides a contribution for a better understanding of the pathomechanisms of S. aureus infections. The proteomic data provide important basic knowledge on strains commonly used in the analysis of S. aureus-host cell interaction.
Hospital Acquired Pneumonia Due to Achromobacter spp. in a Geriatric Ward in China: Clinical Characteristic, Genome Variability, Biofilm Production, Antibiotic Resistance and Integron in Isolated Strains
Liu, Chao; Pan, Fei; Guo, Jun; Yan, Weifeng; Jin, Yi; Liu, Changting; Qin, Long; Fang, Xiangqun
Background: Hospital-acquired pneumonia (HAP) due to Achromobacter has become a substantial concern in recent years. However, HAP due to Achromobacter in the elderly is rare. Methods: A retrospective analysis was performed on 15 elderly patients with HAP due to Achromobacter spp., in which the sequence types (STs), integrons, biofilm production and antibiotic resistance of the Achromobacter spp. were examined. Results: The mean age of the 15 elderly patients was 88.8 ± 5.4 years. All patients had at least three underlying diseases and catheters. Clinical outcomes improved in 10 of the 15 patients after antibiotic and/or mechanical ventilation treatment, but three patients had chronic infections lasting more than 1 year. The mortality rate was 33.3% (5/15). All strains were resistant to aminoglycosides, aztreonam, nitrofurantoin, and third- and fourth-generation cephalosporins (except ceftazidime and cefoperazone). Six new STs were detected. The most frequent ST was ST306. ST5 was identified in two separate buildings of the hospital. ST313 showed higher MIC in cephalosporins, quinolones and carbapenems, which should be more closely considered in clinical practice. All strains produced biofilm and had integron I and blaOXA-114-like. The main type was blaOXA-114q. The variable region of integron I was different among strains, and the resistance gene of the aminoglycosides was most commonly inserted in integron I. Additionally, blaPSE-1 was first reported in this isolate. Conclusion: Achromobacter spp. infection often occurs in severely ill elders with underlying diseases. The variable region of integrons differs, suggesting that Achromobacter spp. is a reservoir of various resistance genes. PMID:27242678
Zhou, Hairui; Yao, Zhenyu; Shi, Haihong; Wang, Baixin; Li, Dong; Hou, Jie
ABSTRACT Staphylococcus succinus subsp. succinus type strain DSM 14617 was isolated from plant and soil inclusions within 25- to 35-million-year-old Dominican amber. The complete genome sequence of strain DSM 14617T includes a genome of 2.88 Mb (32.94% G+C content) without any plasmids. PMID:28126945
Karakawa, W W; Young, D A
The in vitro interactions between strains of Staphylococcus aureus and human polymorphonuclear leukocytes in the presence of immune and nonimmune sera were studied. Evidence indicated that phagocytosis of encapsulated strains occurred in the presence of specific homologous antiserum, whereas non-encapsulated strains were readily phagocytized by polymorphonuclear leukocytes in the presence of both normal and immune sera. Immunological analyses demonstrated that normal serum opsonins, which reacted with the non-encapsulated strains, were specifically directed against exposed mucopeptide moieties of the organisms. Sera rich in antimucopeptide antibodies were obtained from rabbits immunized with heterologous bacteria such as Escherichia coli and group A-variant streptococci and were shown to be effective in opsonizing the non-encapsulated strains of S. aureus. Fresh clinical isolates of S. aureus were noticeably more resistant to the opsonizing effects of the antimucopeptide antibodies. Results were presented which suggest that the surface structures of these clinical isolates are more diverse than laboratory-propagated strains and that these antiphagocytic surface antigens may be significant factors in masking the opsonizing effects of the mucopeptide opsonins which are present in most sera. PMID:478633
Zouhairi, O; Saleh, I; Alwan, N; Toufeili, I; Barbour, E; Harakeh, S
The study evaluated the antimicrobial resistance of molecularly characterized strains of Staphylococcus aureus and S. saprophyticus isolated from 3 Lebanese dairy-based food products that are sometimes consumed raw: kishk, shanklish and baladi cheese. Suspected Staphylococcus isolates were identified initially using standard biochemical tests, then strains that were confirmed by polymerase chain reaction (29 S. aureus and 17 S. saprophyticus) were evaluated for their susceptibility to different antimicrobials. The highest levels of contamination with staphylococci were in baladi cheese. Resistance rates ranged from 67% to gentamicin to 94% to oxacillin and clindamycin. The results suggest that these locally made dairy-based foods may act as vehicles for the transmission of antimicrobial-resistant Staphylococcus spp.
Davis, Meghan F.; Misic, Ana M.; Morris, Daniel O.; Moss, John T.; Tolomeo, Pam; Beiting, Daniel P.; Nachamkin, Irving; Lautenbach, Ebbing; Rankin, Shelley C.
The strain dynamics of methicillin-resistant Staphylococcus aureus (MRSA) isolates from people and the household dog were investigated. The isolates were identified in the context of a randomized controlled trial that tested household-wide decolonization of people. Genotypic comparison of MRSA isolates obtained from two household members, the dog, and home surfaces over a three-month period failed to implicate the pet or the home environment in recurrent colonization of the household members. However, it did implicate the pet’s bed in exposure of the dog prior to the dog’s infection. Whole genome sequencing was performed to differentiate the isolates. This report also describes introduction of diverse strains of MRSA into the household within six weeks of cessation of harmonized decolonization treatment of people and treatment for infection in the dog. These findings suggest that community sources outside the home may be important for recurrent MRSA colonization or infection. PMID:26411322
Mukherjee, Sandipan; Ramesh, Aiyagari
In the present study, the adhesion of bacteriocin-producing probiotic strains of Lactobacillus plantarum onto extracellular matrix (ECM) proteins such as collagen and mucin and their potential to prevent pathogen invasion onto the ECM was ascertained. Fluorescence-based in vitro assays indicated that L. plantarum strains CRA21, CRA38 and CRA52 displayed considerable adhesion to ECM molecules, which was comparable to the probiotic Lactobacillus rhamnosus GG. Flow cytometry-based quantitative assessment of the adhesion potential suggested that L. plantarum CRA21 exhibited superior adhesion onto the ECM as compared with other lactic acid bacteria strains. Furthermore, fluorescence-based assays suggested that the highest inhibition of Staphylococcus aureus adhesion onto collagen and mucin by bacteriocin-producing L. plantarum strains was observed in the exclusion mode as compared with the competition and displacement modes. This observation was supported by the higher binding affinity (k(d)) for the ECM exhibited by the L. plantarum strains as compared with S. aureus. Interestingly, a crude plantaricin A extract from food isolates of L. plantarum displayed potent antibacterial activity on ECM-adhered S. aureus cells. It is envisaged that the L. plantarum isolates displaying bacteriocinogenic and ECM-adhering traits can perhaps be explored to develop safe antibacterial therapeutic agents.
Ritz, H L; Kirkland, J J; Bond, G G; Warner, E K; Petty, G P
Forty-four asymptomatic male subjects were examined for their nasal carriage of strains of Staphylococcus aureus capable of producing staphylococcal toxic shock antigen (TSA), an exotoxin implicated in the pathogenesis of toxic shock syndrome. In addition, the levels of antibody to TSA in sera from these subjects were determined by an enzyme-linked immunosorbent assay. S. aureus was isolated from the anterior nares of 23 subjects. Of those 23 isolates of S. aureus, 9 were found to produce TSA. All individuals carrying strains of S. aureus capable of producing TSA had high to moderate levels of antibody to TSA. In contrast, those individuals carrying strains not producing TSA had levels of antibody to TSA ranging from high to nondetectable. A second examination of nasal samples from 42 of these subjects revealed that 86% of those carrying S. aureus initially still carried S. aureus after a period of 3 months; all subjects found to carry TSA-producing strains initially and that were examined a second time yielded TSA-producing strains once again. PMID:6698614
Sader, Helio S.; Fritsche, Thomas R.; Jones, Ronald N.
A total of 207 Staphylococcus aureus strains, including 105 well-characterized strains with decreased susceptibility to vancomycin (17 vancomycin-intermediate S. aureus [VISA] and 88 heteroresistant VISA [hVISA] strains) and 102 wild-type methicillin-resistant S. aureus (MRSA-WT) strains were tested by reference/standardized broth microdilution and disk diffusion methods, as well as by Etest (AB BIODISK, Solna, Sweden), against daptomycin and vancomycin. The lowest concentration of antimicrobial agent that killed ≥99.9% of the initial inoculum was defined as the minimum bactericidal concentration (MBC) endpoint, and time-kill curves were performed in selected strains to further evaluate bactericidal activity. All MRSA-WT and hVISA strains were inhibited by ≤1 μg/ml of daptomycin, while the VISA strains showed slightly higher daptomycin MICs (range, 0.5 to 4 μg/ml). All daptomycin MBC results were at the MIC or twofold higher. In contrast, 14.7% of MRSA-WT, 69.3% of hVISA, and all VISA strains showed a vancomycin MBC/MIC ratio of ≥32 or an MBC of ≥16 μg/ml (tolerant). The correlation coefficients between broth microdilution and disk diffusion method results were low for daptomycin (0.07) and vancomycin (0.11). Eight (3.8%) strains (all hVISA or VISA) were “nonsusceptible” to daptomycin by broth microdilution methods but susceptible by the disk diffusion method. For vancomycin, 35 (16.9%) strains were nonsusceptible by broth microdilution methods but susceptible by disk diffusion methods. In conclusion, daptomycin was highly bactericidal against S. aureus strains, and its bactericidal activity was not affected by decreased susceptibility to vancomycin. In contrast, many (one in seven) contemporary MRSA-WT, the majority of hVISA, and all VISA strains showed vancomycin MBC/MIC ratios consistent with tolerance, a predictor of poor clinical response. Disk diffusion tests generally failed to detect strains categorized as nonsusceptible to daptomycin or
Nordmann, Patrice; Naas, Thierry; Fortineau, Nicolas; Poirel, Laurent
New resistance problems have emerged recently among hospital and community-acquired pathogens such as in Staphylococcus aureus, Enterococcus faecium and Pseudomonas aeruginosa. Hospital-acquired and now community-acquired methicillin-resistant S. aureus are emerging worldwide whereas vancomycin-resistant S. aureus remain extremely rare. Hospital-acquired outbreaks of vancomycin-resistant enterococci and multidrug resistant Pseudomonas aeruginosa infections are increasingly reported worldwide. Whereas novel molecules are being developed for treating Gram-positive infections, difficult to non possible-to-treat pandrug-resistant P. aeruginosa infections may become a therapeutic challenge soon.
Jaton, L; Pillonel, T; Jaton, K; Dory, E; Prod'hom, G; Blanc, D S; Tissot, F; Bodenmann, P; Greub, G
Since late 2014, multiple cases of abscesses and boils due to methicillin-susceptible Staphylococcus aureus (MSSA) expressing the Panton-Valentine leucocidin (PVL) were observed in Eritrean asylum seekers in Lausanne, Switzerland. Strains isolated from infected Eritrean and non-Eritrean patients were compared by whole genome sequencing to determine whether these numerous cases result from an outbreak. The genome of S. aureus PVL-producing strains were sequenced and compared. Clinical and epidemiological characteristics of patients infected by PVL-producing strains were investigated. This work reports 15 cases of infections due to PVL-producing strains affecting mostly asylum seekers (n = 10), people working with refugees and/or exposed to Africans (n = 3). Most infections were due to closely related strains of CC152 (n = 8) and CC15 (n = 3), two distantly related (>34 000 core single nucleotide polymorphisms) clonal complexes. An epidemiological link between the 15 cases could be ruled out by whole genome sequencing (33 to 172 core single nucleotide polymorphisms between the different strains of a given complex). Altogether, these results reflect the probable high incidence of CC15 and CC152 PVL-producing strains in eastern Africa. Clinicians facing unusual skin infections in African refugees (or in any person returning from this region of high endemicity) should consider S. aureus PVL-producer before suspecting rare infections such as leishmaniasis or rickettsiosis. Clinicians should also remember that PVL are frequently expressed by MSSA in some regions of the world and that antibiotics that are efficient on toxin expression, such as clindamycin, represent the best therapeutic option.
Cebrián, G; Sagarzazu, N; Pagán, R; Condón, S; Mañas, P
The survival of four enterotoxigenic strains of Staphylococcus aureus (with different pigment content) to heat and to pulsed electric fields (PEF) treatments, and the increase in resistance to both processing stresses associated with entrance into stationary phase was examined. Survival curves to heat (58 degrees C) and to PEF (26 kV/cm) of cells in the stationary and in the exponential phase of growth were obtained. Whereas a wide variation in resistance to heat treatments was detected amongst the four strains, with decimal reduction time values at 58 degrees C (D(58 degrees C)) ranging from 0.93 to 0.20 min, the resistance to PEF was very similar. The occurrence of a higher tolerance to heat in stationary phase was coincident with a higher content in carotenoid pigmentation in S. aureus colonies. However, cells of the most heat resistant (pigmented) and the most heat sensitive (non-pigmented) strains in the mid-exponential phase of growth showed similar resistance to heat and to PEF. Therefore the increase in thermotolerance upon entrance into stationary phase of growth was more marked for the pigmented strains. Recovery in anaerobic conditions particularly enhanced survival to heat treatments in a non-pigmented strain. Strain CECT 4630, which possess a deficient sigma B activity, showed low heat resistance, low pigmentation, and reduced increase in thermotolerance in stationary phase. These results indicate that the magnitude of the development of a higher heat resistance in S. aureus in stationary phase is positively related to the carotenoid content of the strain. The development of tolerance to pulsed electric field was less relevant and not linked to the carotenoid content.
Cardot Martin, E; Michel, A; Raynal, B; Badiou, C; Laurent, F; Vandenesch, F; Etienne, J; Lina, G; Dumitrescu, O
Community-acquired meticillin-resistant Staphylococcus aureus (CA-MRSA) causes severe diseases through virulence factors such as staphylococcal protein A (SpA), which favours immune evasion. We have previously shown that antimicrobial peptides (AMPs) and antibiotics decrease SpA expression in CA-MRSA strains. Here we examined the effects of antibiotics and AMPs, alone and in combination, on SpA expression in various CA-MRSA strains. Six S. aureus isolates corresponding to the major worldwide CA-MRSA clones (ST8-USA300, ST80 and ST30) were selected. Strains were cultured to exponential growth phase and were subsequently incubated with antibiotics (tigecycline, linezolid, clindamycin and vancomycin) at 0.25× MIC or with AMPs [human neutrophil peptide (HNP)-1-3] at the LD50, alone and in combination. After 6h, cultures were assessed for spa mRNA by RT-PCR, whilst SpA protein was measured by specific ELISA after 18h. When used alone, antibiotics (clindamycin, linezolid and tigecycline) or HNPs significantly reduced both SpA production and mRNA levels in ST30 and ST80 strains. When used in combination, HNPs and clindamycin, linezolid or tigecycline synergistically reduced SpA production (6-100-fold) and spa mRNA levels (4-20-fold) in ST80 and ST30 strains. In contrast, for USA300 strains, among all antibiotics, clindamycin alone reduced SpA production (3.5-fold), whereas with combined treatments including HNPs, only a slight reduction in SpA production (1.7-2.2-fold) was observed. In conclusion, antibiotics and AMPs do not modulate SpA expression in USA300, unlike in other CA-MRSA clones. This observation suggests that the virulence and successful spread of USA300 strains is associated with a specific regulatory network.
Pastagia, Mina; Euler, Chad; Chahales, Peter; Fuentes-Duculan, Judilyn; Krueger, James G; Fischetti, Vincent A
Staphylococcus aureus is a major human pathogen responsible for a number of serious and sometimes fatal infections. One of its reservoirs on the human body is the skin, which is known to be a source of invasive infection. The potential for an engineered staphylococcus-specific phage lysin (ClyS) to be used for topical decolonization is presented. We formulated ClyS into an ointment and applied it to a mouse model of skin colonization/infection with S. aureus. Unlike the standard topical antibacterial agent mupirocin, ClyS eradicated a significantly greater number of methicillin-susceptible S. aureus (MSSA) and -resistant S. aureus (MRSA) bacteria: a 3-log reduction with ClyS as opposed to a 2-log reduction with mupirocin in our model. The use of ClyS also demonstrated a decreased potential for the development of resistance by MRSA and MSSA organisms compared to that from the use of mupirocin in vitro. Because antibodies may affect enzyme function, we tested antibodies developed after repeated ClyS exposure for their effect on ClyS killing ability. Our results showed no inhibition of ClyS activity at various antibody titers. These data demonstrate the potential of developing ClyS as a novel class of topical antimicrobial agents specific to staphylococcus.
Background In this study mass spectrometry was used for evaluating extracted leptospiral protein samples and results were compared with molecular typing methods. For this, an extraction protocol for Leptospira spp. was independently established in two separate laboratories. Reference spectra were created with 28 leptospiral strains, including pathogenic, non-pathogenic and intermediate strains. This set of spectra was then evaluated on the basis of measurements with well-defined, cultured leptospiral strains and with 16 field isolates of veterinary or human origin. To verify discriminating peaks for the applied pathogenic strains, statistical analysis of the protein spectra was performed using the software tool ClinProTools. In addition, a dendrogram of the reference spectra was compared with phylogenetic trees of the 16S rRNA gene sequences and multi locus sequence typing (MLST) analysis. Results Defined and reproducible protein spectra using MALDI-TOF MS were obtained for all leptospiral strains. Evaluation of the newly-built reference spectra database allowed reproducible identification at the species level for the defined leptospiral strains and the field isolates. Statistical analysis of three pathogenic genomospecies revealed peak differences at the species level and for certain serovars analyzed in this study. Specific peak patterns were reproducibly detected for the serovars Tarassovi, Saxkoebing, Pomona, Copenhageni, Australis, Icterohaemorrhagiae and Grippotyphosa. Analysis of the dendrograms of the MLST data, the 16S rRNA sequencing, and the MALDI-TOF MS reference spectra showed comparable clustering. Conclusions MALDI-TOF MS analysis is a fast and reliable method for species identification, although Leptospira organisms need to be produced in a time-consuming culture process. All leptospiral strains were identified, at least at the species level, using our described extraction protocol. Statistical analysis of the three genomospecies L. borgpetersenii
Bemis, David A; Jones, Rebekah D; Hiatt, Lauren E; Ofori, Edward D; Rohrbach, Barton W; Frank, Linda A; Kania, Stephen A
Multiple tests were compared to the reference standard PBP2a latex agglutination test for detection of mecA-mediated oxacillin resistance in canine staphylococci. Cefoxitin disk diffusion, using breakpoints for human isolates of coagulase-negative Staphylococcus spp., had low sensitivity for detection of oxacillin resistance in members of the Staphylococcus intermedius group.
Goudarzi, Mehdi; Bahramian, Mahnaz; Satarzadeh Tabrizi, Mahboobeh; Udo, Edet E; Figueiredo, Agnes Marie Sá; Fazeli, Maryam; Goudarzi, Hossein
Methicillin-resistant Staphylococcus aureus (MRSA) as a major cause of infection in health care, hospital and community settings is a global health concern. The purpose of this study was to determine the antibiotic susceptibility pattern and distribution of circulating molecular types of MRSA in a burn hospital in Tehran, the capital of Iran. During a 10-month study period, 106 Staphylococcus aureus isolates were assessed. Isolates were subjected to susceptibility testing using the disk diffusion method and Polymerase Chain Reaction (PCR) for detection of mecA, fem and nuc genes. The presence of PVL and tst encoding genes were determined by PCR method. All the MRSA isolates were genotyped by multilocus sequence typing (MLST), spa typing, SCCmec typing and agr typing. The presence of mecA gene was confirmed in all the Staphylococcus aureus isolates. Antimicrobial susceptibility testing revealed a high resistance rate (90.6%) to ampicillin, tetracycline, and erythromycin. The rates of resistance to remaining antibiotics tested varied between 18.9% and 84.9%. The high- level of resistance to mupirocin was confirmed in 19.8% of MRSA strains isolated from burn patients. Multi-drug resistance was observed in 90.6% of isolates. Sixteen of the 106 MRSA isolates (15.1%) harbored PVL-encoding genes. The majority of our MRSA strains carried SCCmec III (71.7%). ST239-SCCmec III/t037 (34%) was the most common genotype followed by ST239-SCCmec III/t030 (24.5%), ST15-SCCmec IV/t084 (15.1%), ST22-SCCmec IV/t790 (13.2%), and ST239-SCCmec III/t631 (13.2%). Mupirocin resistant MRSA isolates belonged to ST15-SCCmec IV/t084 (40%), ST22-SCCmec IV/t790 (23.3%), ST239-SCCmec III/t631 (20%), and ST239-SCCmec III/t030 (16.7%) clones. The results showed that genetically diverse strains of MRSA are circulating in our burn hospitals with relatively high prevalence of ST239-SCCmec III/t037 clone. The findings support the need for regular surveillance of MRSA to determine the distribution of
Favier, Gabriela Isabel; Lucero Estrada, Cecilia; Cortiñas, Teresa Inés; Escudero, María Esther
Shiga toxin producing Escherichia coli (STEC), Salmonella spp., and Yersinia species was investigated in humans, animals, and foods in San Luis, Argentina. A total of 453 samples were analyzed by culture and PCR. The antimicrobial susceptibility of all the strains was studied, the genomic relationships among isolates of the same species were determined by PFGE, and the potencial virulence of Y. enterocolitica strains was analyzed. Yersinia species showed higher prevalence (9/453, 2.0%, 95% CI, 0.7–3.3%) than STEC (4/453, 0.9%, 95% CI, 0–1.8%) and Salmonella spp. (3/453, 0.7%, 95% CI, 0–1.5%). Y. enterocolitica and Y. intermedia were isolated from chicken carcasses (6/80, 7.5%, 95% CI, 1.5–13.5%) and porcine skin and bones (3/10, 30%, 95% CI, 0–65%). One STEC strain was recovered from human feces (1/70, 1.4%, 95% CI, 0–4.2%) and STEC stx1/stx2 genes were detected in bovine stools (3/129, 2.3%, 95% CI, 0–5.0%). S. Typhimurium was isolated from human feces (1/70, 1.4%, 95% CI, 0–4.2%) while one S. Newport and two S. Gaminara strains were recovered from one wild boar (1/3, 33%, 95% CI, 0–99%). The knowledge of prevalence and characteristics of these enteropathogens in our region would allow public health services to take adequate preventive measures. PMID:25177351
Snel, G G M; Malvisi, M; Pilla, R; Piccinini, R
It was hypothesized that biofilm could play an important role in the establishment of chronic Staphylococcus aureus bovine mastitis. The in vitro evaluation of biofilm formation can be performed either in closed/static or in flow-based systems. Efforts have been made to characterize the biofilm-forming ability of S. aureus mastitis isolates, however most authors used static systems and matrices other than UHT milk. It is not clear whether such results could be extrapolated to the mammary gland environment. Therefore, the present study aimed to investigate the biofilm-forming ability of S. aureus strains from subclinical bovine mastitis using the static method and a flow-based one. One hundred and twelve strains were tested by the classic tissue culture plate assay (TCP) and 30 out of them were also tested by a dynamic semi-quantitative assay using commercial UHT milk as culture medium (Milk Flow Culture, MFC) or Tryptic Soy Broth as control medium (TS Flow Culture, TSFC). Only 6 (20%) strains formed biofilm in milk under flow conditions, while 36.6% were considered biofilm-producers in TCP, and 93.3% produced biofilm in TSFC. No agreement was found between TCP, MFC and TSFC results. The association between strain genetic profile, determined by microarray, and biofilm-forming ability in milk was evaluated. Biofilm formation in MFC was significantly associated with the presence of those genes commonly found in bovine-associated strains, assigned to clonal complexes typically detected in mastitis. Based on our results, biofilm-forming potential of bovine strains should be critically analysed and tested applying conditions similar to mammary environment.
Radiastuti, Nani; Mutea, Dalli; Sumarlin, La Ode
An endophytic fungus is microorganisms that live inside plant tissues without harming its host and is capable of producing the same secondary metabolites as its host plant. The endophytic fungus is very diverse and important group of microorganisms. The objectives of the study are to identify endophyte Colletotrichum spp. using ITS rDNA analyze, alkaloid cinchona and antibacterial characteristics. Phylogenetic analysis of ITS rDNA regions and morphology are used to identify the species. The Chloroform extracts of filtrate were analyzed using the High Pressure Liquid Chromatography (HPLC) to determine the production of quinine. There were 13 isolates of Colletotrichum spp as endophytes with associated with Cinchona calisaya Wedd. from fruit (6 isolates), leaf (5 isolates), twig (1 isolate) and root (1 isolate). This is the first report as endophytes are associated with C. calisaya. Based on ITS phylogenetic analysis are introduced of 7 strains Colletotrichum sp, 1 strain closely with C. aegnigma, 2 strains closely C. cordylinicola, 1 strains C arxii, 2 strains nested C. karstii. The Colletotrichum sp. M1 (leaf), M3 (bark), M8 (fruit) and C. karstii M5 (fruit) are potential alkaloid quinine. Five strains of Colletotrichum spp. have antibacterial activity are selected against Staphylococcus aureus and nine Colletotrichum spp. against Escherichia coli. The endophyte identification of Colletotrichum species needs another gene other than ITS rDNA.
Shamsutdinov, A F; Tiurin, Iu A
Main scientific-research studies regarding protein bacterial toxins of the most widespread bacteria that belong to Staphylococcus spp. genus and in particular the most pathogenic species for humans--Staphylococcus aureus, are analyzed. Structural and biological properties of protein toxins that have received the name of staphylococcus pyrogenic toxins (PTSAg) are presented. Data regarding genetic regulation of secretion and synthesis of these toxins and 3 main regulatory genetic systems (agr--accessory gene regulator, xpr--extracellular protein regulator, sar--staphylococcal accessory regulator) that coordinate synthesis of the most important protein toxins and enzymes for virulence of S. aureus, are presented.
Antimicrobial activity of honey of stingless bees, tiúba (Melipona fasciculata) and jandaira (Melipona subnitida) compared to the strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa
Tenório, Eleuza Gomes; de Jesus, Natália Rocha; Nascimento, Adenilde Ribeiro; Teles, Amanda Mara
This study aimed to investigate the antimicrobial activity of honeys of stingless bees produced in Maranhão, tiúba (Melipona fasciculata) and jandaira (Melipona subnitida), opposite the strains of pathogenic bacteria, namely, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The honey samples were collected from different regions of Maranhão. Of the 17 samples collected, twelve samples were honey M. fasciculata and five were honey M. subnitida. We used the Kirby-Bauer method, and the technique of agar disk diffusion through the extent of inhibition in milimetros. Results were negative for all samples from M. fasciculata. However, the tests for M. subnitida demonstrated bacteriostatic halos ranging from 12 to 32,6mm.
Haraga, Isao; Abe, Shintaro; Jimi, Shiro; Kiyomi, Fumiaki; Yamaura, Ken
Staphylococcus spp. is a major cause of device-related infections. However, the mechanisms of deep-tissue infection by staphylococci from the skin surface remain unclear. We performed in vitro experiments to determine how staphylococci are transferred from the surface to the deeper layers of agar along the catheter for different strains of Staphylococcus aureus with respect to bacterial concentrations, catheter movements, and biofilm formation. We found that when 5-mm reciprocal movements of the catheter were repeated every 8h, all catheter samples of S. aureus penetrated the typical distance of 50mm from the skin to the epidural space. The number of reciprocal catheter movements and the depth of bacterial growth were correlated. A greater regression coefficient for different strains implied faster bacterial growth. Enhanced biofilm formation by different strains implied larger regression coefficients. Increased biofilm formation ability may accelerate S. aureus transport along a catheter due to physical movements by patients.
Guo, Jun; Han, Na; Zhang, Yuanyuan; Wang, Haiyin; Zhang, Xuelin; Su, Longxiang; Liu, Chao; Li, Jia; Chen, Chen; Liu, Changting
The extreme environment of space could affect microbial behavior and may increase the risk of infectious disease during spaceflight. However, the molecular genetic changes of methicillin-resistant Staphylococcus aureus (MRSA) in response to the spaceflight environment have not been fully clarified. In the present study, we determined the draft genome sequences for an ancestral S. aureus strain (LCT-SAO) isolated from a clinical sample and three derivative strains, LCT-SAS, LCT-SAM and LCT-SAG, cultured in parallel during the spaceflight Shenzhou-X, under simulated microgravity and on the ground, respectively. To evaluate the impact of short-term spaceflight on the MRSA strains, comparative genomic analysis was implemented. Genome-based mapping of toxin genes and antibiotic resistance genes confirmed that these strains have the conventional pathogenicity and resistance to drugs, as none of the strains showed significant changes in these regions after culturing in the three different environments; this result suggests that spaceflight may not change bacterial virulence or drug resistance. Thirty-nine strain-specific sequence variants (SVs) were identified throughout the genomes, and the three derivatives exhibited almost the same mutation rates. Fifty-nine percent of SVs were located in the intergenic regions of the genomes, indicating that S. aureus may have an extremely robust repair mechanism responsible for recognizing and repairing DNA replication mismatches. It is noteworthy that strain LCT-SAS, cultured in space, presented the most unique SVs (n=9) and shared the fewest SVs with LCT-SAM (n=5) and LCT-SAG (n=4). Furthermore, we identified 10 potential deletion regions and 2 potential insertion regions, with LCT-SAS appearing more fragile than other strains by this measure. These results suggest that the environment of space is inherently complicated, with multiple variables, and cannot be simulated in a simple manner. Our results represent the first analysis of
Neill, R J; Fanning, G R; Delahoz, F; Wolff, R; Gemski, P
Different synthetic DNA nucleotide sequences were evaluated as gene probes for the specific detection and differentiation of Staphylococcus aureus strains encoding enterotoxins A (SEA), B (SEB), and C (SEC) and toxic shock syndrome toxin 1 (TSST-1). Identification of sequences unique to each toxin, based on knowledge of their nucleotide sequences, led to preparation of the specific 18-base oligonucleotide probes EA1 (encoding amino acids 177 to 182 of SEA), EB2 (encoding amino acids 105 to 110 of SEB), EC5 (encoding amino acids 125 to 131 of SEC1), and TS1 (encoding amino acids 160 to 166 of TSST-1). In colony blot hybridization analyses, these probes hybridized specifically with DNA from strains that produced the respective toxin serotypes. An excellent (greater than or equal to 93%) correlation between hybridization results (genotype) and toxin protein detection by an enzyme-linked immunosorbent assay (phenotype) was observed in the characterization of both reference and clinical strains of S. aureus for SEA, SEB, and TSST-1. A lower correlation (64%) for SEC reflected a lack of sensitivity in detecting toxin production. Our findings demonstrate that molecular DNA hybridization with synthetic oligonucleotide probes provides another approach for establishing the toxigenicity of S. aureus. Images PMID:2380378
Watanabe, Shinya; Ito, Teruyo; Morimoto, Yuh; Takeuchi, Fumihiko; Hiramatsu, Keiichi
Large-scale chromosomal inversions (455 to 535 kbp) or deletions (266 to 320 kbp) were found to accompany spontaneous loss of beta-lactam resistance during drug-free passage of the multiresistant Staphylococcus haemolyticus clinical strain JCSC1435. Identification and sequencing of the rearranged chromosomal loci revealed that ISSha1 of S. haemolyticus is responsible for the chromosome rearrangements.
Pincus, Nathan B.; Jammeh, Momodou L.; Datta, Sandip K.; Myles, Ian A.
The response to multi-drug resistant bacterial infections must be a global priority. While mounting resistance threatens to create what the World Health Organization has termed a “post-antibiotic era”, the recent discovery that antibiotic use may adversely impact the microbiome adds further urgency to the need for new developmental approaches for anti-pathogen treatments. Methicillin-resistant Staphylococcus aureus (MRSA), in particular, has declared itself a serious threat within the United States and abroad. A potential solution to the problem of antibiotic resistance may not entail looking to the future for completely novel treatments, but instead looking into our history of bacteriophage therapy. This study aimed to test the efficacy, safety, and commercial viability of the use of phages to treat Staphylococcus aureus infections using the commercially available phage SATA-8505. We found that SATA-8505 effectively controls S. aureus growth and reduces bacterial viability both in vitro and in a skin infection mouse model. However, this killing effect was not observed when phage was cultured in the presence of human whole blood. SATA-8505 did not induce inflammatory responses in peripheral blood mononuclear cultures. However, phage did induce IFN gamma production in primary human keratinocyte cultures and induced inflammatory responses in our mouse models, particularly in a mouse model of chronic granulomatous disease. Our findings support the potential efficacy of phage therapy, although regulatory and market factors may limit its wider investigation and use. PMID:25909449
Reubel, Gerhard H.; Barlough, Jeffrey E.; Madigan, John E.
We report on the production and characterization of Ehrlichia risticii, the agent of Potomac horse fever (PHF), from snails (Pleuroceridae: Juga spp.) maintained in aquarium culture and compare it genetically to equine strains. Snails were collected from stream waters on a pasture in Siskiyou County, Calif., where PHF is enzootic and were maintained for several weeks in freshwater aquaria in the laboratory. Upon exposure to temperatures above 22°C the snails released trematode cercariae tentatively identified as virgulate cercariae. Fragments of three different genes (genes for 16S rRNA, the groESL heat shock operon, and the 51-kDa major antigen) were amplified from cercaria lysates by PCR and sequenced. Genetic information was also obtained from E. risticii strains from horses with PHF. The PCR positivity of snail secretions was associated with the presence of trematode cercariae. Sequence analysis of the three genes indicated that the source organism closely resembled E. risticii, and the sequences of all three genes were virtually identical to those of the genes of an equine E. risticii strain from a property near the snail collection site. Phylogenetic analyses of the three genes indicated the presence of geographical E. risticii strain clusters. PMID:9620368
Antibiotic Resistance in Staphylococcus aureus Strains Isolated from Cows with Mastitis in Eastern Poland and Analysis of Susceptibility of Resistant Strains to Alternative Nonantibiotic Agents: Lysostaphin, Nisin and Polymyxin B
SZWEDA, Piotr; SCHIELMANN, Marta; FRANKOWSKA, Aneta; KOT, Barbara; ZALEWSKA, Magdalena
ABSTRACT The aim of this study was to analyze the resistance of Staphylococcus aureus isolates from bovine mastitis in the eastern part of Poland to a set of 20 antibiotics and three alternative agents: lysostaphin, nisin and polymyxin B. Eighty-six out of 123 examined isolates were susceptible to all 20 tested antibiotics (70%). The highest percentage of resistance was observed in the case of β-lactam antibiotics: amoxicillin (n=22, 17.9%), ampicillin (n=28, 22.8%), penicillin (n=29, 23.6%) and streptomycin (n=13; 10.6%). Twenty-five of the penicillin-resistant strains were found to carry the blaZ gene coding for β-lactamases. Two strains were found to be mecA positive and a few strains were classified as multidrug resistant (MDR), one of them was simultaneously resistant to six antibiotics. All strains, resistant to at least one antibiotic (n=37) and two control strains, were susceptible to lysostaphin with MIC values of 0.008–0.5 µg/ml (susceptibility breakpoint 32 µg/ml). Twenty-one (54%) isolates were susceptible to nisin. The MIC value of this agent for 17 (44%) strains was 51.2 µg/ml and was not much higher than the susceptibility breakpoint value (32 µg/ml). Polymyxin B was able to inhibit the growth of the strains only at a high concentration (32–128 µg/ml). The presented results confirmed the observed worldwide problem of spreading antibiotic resistance among staphylococci isolated from bovine mastitis; on the other hand, we have indicated a high level of bactericidal activity of nisin and especially lysostaphin. PMID:24212507
Hammer, Katherine A; Carson, Christine F; Riley, Thomas V
This study was conducted to determine the frequencies at which single-step mutants resistant to tea tree oil and rifampicin occurred amongst the Gram-positive organisms Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis. For tea tree oil, resistance frequencies were very low at <10(-9). Single-step mutants resistant to tea tree oil were undetectable at two times the minimum inhibitory concentration (MIC) for S. aureus RN4220 and derivative mutator strains or at 3 x MIC for the remaining S. aureus strains, including a clinical meticillin-resistant S. aureus isolate. Similarly, no mutants were recovered at 2x MIC for S. epidermidis or at 1x MIC for E. faecalis. Resistance frequencies determined in vitro for rifampicin (8 x MIC) ranged from 10(-7) to 10(-8) for all isolates, with the exception of the S. aureus mutator strains, which had slightly higher frequencies. These data suggest that Gram-positive organisms such as Staphylococcus and Enterococcus spp. have very low frequencies of resistance to tea tree oil.
Gülmez, Dolunay; Sancak, Banu; Ercis, Serpil; Karakaya, Jale; Hasçelik, Gülşen
Infections due to methicillin-resistant Staphylococcus aureus (MRSA) are important health care problems since they are usually multidrug resistant. Although MRSA is isolated especially from nosocomial infections, community-acquired MRSA infections are increasing. Methicillin resistance is due to the expression of mecA gene, which is located on SCCmec gene cassette. Different SCCmec types can be detected in hospital-acquired and community-acquired (CA-) MRSA strains. CA-MRSA strains might harbour Panton-Valentine leukocidin (PVL), an important virulence factor in skin and soft tissue infections. Strains carrying PVL has the ability to penetrate undamaged skin and cause more severe infections. The aim of this study was to detect SCCmec types and PVL gene in S.aureus strains isolated from skin and soft tissue infections and to compare with strains isolated from other infections in a university hospital in Ankara, Turkey. S.aureus strains isolated from skin and soft tissue infections (n= 285) and a control group consisting of 161 strains isolated from other infections (53 blood, 48 lower respiratory tract samples, 30 sterile body fluids, 30 genitourinary tract samples) chosen by stratification and random selection method, were included in the study. Among skin and soft tissue infection strains 46.7% were from the hospitalized patients and 48.4% of skin and soft tissue infection strains were from female patients. The mean age of the skin and soft tissue infection patients was 45.5 years. Among the control strains 60.9% were from the hospitalized patients and 41.6% of the control patients were female. The mean age of the control patients was 50.2 years. Strains were identified by the Phoenix system (Becton Dickinson, USA) and identification was confirmed by tube coagulase test. Methicillin resistance was determined by the Phoenix system which determines both oxacillin and cefoxitin minimum inhibitor concentrations and, confirmed by oxacillin agar screening and
Garita-Cambronero, Jerson; Palacio-Bielsa, Ana; López, María M.
The draft genome sequences of two strains of Xanthomonas arboricola, isolated from asymptomatic peach trees in Spain, are reported here. These strains are avirulent and do not belong to the same phylogroup as X. arboricola pv. pruni, a causal agent of bacterial spot disease of stone fruits and almonds. PMID:27609931
Bhattacharya, Susmita; Jain, Sonia; Chatterjee, Shiv Sekhar; Konar, Jayashree
Introduction Surgical Site Infection (SSI) is the most common healthcare associated infection that could be averted by antibiotics prophylaxis against the probable offending organisms. As Staphylococcus aureus has been playing a substantial role in the aetiology of SSIs, Methicillin Resistant Staphylococcus aureus (MRSA) happens to be a problem while dealing with the postoperative wound infection. Aim To determine the prevalence of SSI caused by MRSA and the antibiotic sensitivity pattern of MRSA. Materials and Methods A cross-sectional study was conducted at Nil Ratan Sircar Medical College, Kolkata, West Bengal from July 2009 to December 2012. A total of 19,359 surgical procedures were done of which 3003 culture positive SSIs have been documented. The clinical samples were collected from patients of both sexes and all ages suspected to be suffering from SSI from different specialities. Samples were processed according to CLSI, 2007 guidelines. The isolated strains of Staphylococcus aureus were screened for MRSA by detection of resistance to Cefoxitin disc (zone of inhibition was ≤21 mm) and slidex staph latex agglutination tests were done on cefoxitin resistant strains to spot phenotypic expression of mec A gene. Then PCR was performed for detection of mecA gene. Antibiotic sensitivity test was done following Kirby Bauer technique. Results In this 3½ year study, 1049 Staphylococcus aureus (34.93%) were reported from 3003 cases of SSI followed by Escherichia coli (20.34%), Klebsiella spp. (18.08%), Pseudomonas spp. (7.99%), Acinetobacter spp. (7.49%) respectively. Among the Staphylococcus aureus, 267 strains were derived as MRSA (25.45%). MRSA were isolated from 167 (62.54%) male patients and 100 (37.45%) female patients having surgical site infections. Inpatients and outpatients distribution of MRSA were 235 (88.01%) and 32 (11.98%) respectively. Majority of the MRSA cases were reported from Surgery (12.49%) and Orthopaedics (11.85%) departments in the age
Reeve, Wayne; Sullivan, John; Ronson, Clive; Tian, Rui; Munk, Christine; Han, Cliff; Reddy, T. B. K.; Seshadri, Rekha; Woyke, Tanja; Pati, Amrita; Markowitz, Victor; Ivanova, Natalia; Kyrpides, Nikos
Mesorhizobium loti strain CJ3Sym was isolated in 1998 following transfer of the integrative and conjugative element ICE Ml SymR7A , also known as the R7A symbiosis island, in a laboratory mating from the donor M. loti strain R7A to a nonsymbiotic recipient Mesorhizobium strain CJ3. Strain CJ3 was originally isolated from a field site in the Rocklands range in New Zealand in 1994. CJ3Sym is an aerobic, Gram-negative, non-spore-forming rod. This report reveals the genome of M. loti strain CJ3Sym currently comprises 70 scaffolds totaling 7,563,725 bp. In conclusion, the high-quality draft genome is arranged in 70 scaffolds of 71 contigs, contains 7,331 protein-coding genes and 70 RNA-only encoding genes, and is part of the GEBA-RNB project proposal.
Reeve, Wayne; Sullivan, John; Ronson, Clive; ...
Mesorhizobium loti strain CJ3Sym was isolated in 1998 following transfer of the integrative and conjugative element ICE Ml SymR7A , also known as the R7A symbiosis island, in a laboratory mating from the donor M. loti strain R7A to a nonsymbiotic recipient Mesorhizobium strain CJ3. Strain CJ3 was originally isolated from a field site in the Rocklands range in New Zealand in 1994. CJ3Sym is an aerobic, Gram-negative, non-spore-forming rod. This report reveals the genome of M. loti strain CJ3Sym currently comprises 70 scaffolds totaling 7,563,725 bp. In conclusion, the high-quality draft genome is arranged in 70 scaffolds of 71more » contigs, contains 7,331 protein-coding genes and 70 RNA-only encoding genes, and is part of the GEBA-RNB project proposal.« less
Goudarzi, Mehdi; Fazeli, Maryam; Goudarzi, Hossein; Azad, Mehdi; Seyedjavadi, Sima Sadat
Background The incidence of nosocomial Staphylococcus aureus infection is increasing annually and becoming a true global challenge. The pattern of Staphylococcus aureus protein A (spa) types in different geographic regions is diverse. Objectives This study determined the prevalence of methicillin-resistant S. aureus and different spa types in S. aureus clinical isolates. Materials and Methods During a six-month period, 90 S. aureus isolates were recovered from 320 clinical specimens. The in vitro susceptibility of various S. aureus isolates to 16 antibiotic discs was assessed using the Kirby-Bauer disk diffusion method. Molecular typing was carried out with S. aureus protein A typing via polymerase chain reaction. Results The frequency of methicillin-resistant S. aureus in our study was 88.9%. Twenty-three (25.5%) isolates were positive for panton-valentine leukocidin encoding genes. S. aureus presented a high resistance rate to ampicillin (100%) and penicillin (100%). No resistance was observed to vancomycin, teicoplanin, or linezolid. The rates of resistance to the majority of antibiotics tested varied between 23.3% and 82.2%. The rate of multidrug resistance among these clinical isolates was 93.3%. The 90 S. aureus isolates were classified into five S. aureus protein A types: t037 (33.3%), t030 (22.2%), t790 (16.7%), t969 (11.1%), and t044 (7.7%). Eight (8.9%) isolates were not typable using the S. aureus protein A typing method. Conclusions We report a high methicillin-resistant S. aureus rate in our hospital. Additionally, t030 and t037 were the predominant spa-types among hospital-associated S. aureus. Our findings emphasize the need for continuous surveillance to prevent the dissemination of multidrug resistance among different S. aureus protein A types in Iran. PMID:27679706
Rota, A; Milani, C; Corrò, M; Drigo, I; Börjesson, S
Methicillin-resistant Staphylococcus pseudintermedius (MRSP) strains have been isolated from dogs with increasing frequency; prolonged or excessive use of antimicrobials is associated with the selection of MRSP, and misuse of antimicrobials is frequent in breeding kennels. This study was carried out in two breeding kennels (A and B) in which we had isolated MRSP in 2008: the aim was to assess colonization of previously positive bitches and of other bitches sharing the same environment and to assess the genetic profile of both the old and the new strains [spa typing, staphylococcal cassette chromosome mec (SCCmec) typing and Pulsed-field Gel Electrophoresis (PFGE)]. Six animals from Kennel A (two from 2008) and eight from Kennel B (one from 2008) were tested: 16 MRSP strains were isolated only from bitches housed in Kennel B. Old and new isolates were mecA positive, resulted spa type t02 and carried SSCmec II-III. PGFE showed that all isolates were related and belonged to the main clone lineage dominating in Europe, ST71-J-t02-II-III. Kennels A and B differ in the use of antimicrobials, which has been reduced over time in Kennel A, while has remained excessive in Kennel B, where many agents belonging to different classes (third-generation cephalosporins, fluoroquinolones, macrolids) are administered to dogs, without veterinary supervision, especially around parturition. Misuse of antimicrobials is the key factor for the selection of MRSP strains in healthy dogs and for their persistence over time. Dog breeders should be aware that infections caused by multiresistant bacteria have very limited therapeutical options and represent a huge challenge for animal health.
Lim, King Ting; Hanifah, Yasmin Abu; Yusof, Mohd Yasim Mohd; Goering, Richard V; Thong, Kwai Lin
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the main bacterial pathogens responsible for nosocomial infections leading to pneumonia, bloodstream, skin, and soft tissue infections. The objective of this study was to investigate the genomic changes of MRSA in a tertiary hospital between the years 2003, 2004, 2007, and 2008. One hundred fifty-four MRSA strains were characterized by multilocus sequence typing (MLST), spa, and mec-associated dru typing. Among the 154 strains, 29 different dru, 15 spa, and 8 MLST types were identified. Seven sequence types (STs) (ST239, ST22, ST5, ST6, ST80, ST573, and ST241) were identified among 2007-08 strains, although only 2 STs (ST239 and ST20) were observed among 2003 strains. Clones ST239-t037-dt13g, ST22-t032-(dt10a and dt10aw), and 28 other MRSA clones being introduced in 2007-2008 have replaced the ST239-t037 (dt13d, 14h, 13i, 13l, 13m, 15m, 15l, and 11al) clones present in 2003. The predominant MLST clone, ST239 (90.3%), was further distinguished into 7 different spa types and 26 different dru types, including 17 novel dru types. Maximum parsimony tree based on dru repeats revealed that 10 dru types (dt11am, dt13j, dt15n, dt13q, dt13n, dt13p, dt13f, dt13ao, dt12j, dt7v) shared the same MLST-spa types with dt13d, suggesting that these MRSA clones might have evolved from ST239-t037-dt13d. In conclusion, our data showed that the ST239-t037-dt13d clone and other MRSA clones in 2003 were replaced by ST239-t037-dt13g and other new emerging spa and dru types.
Clarridge, Jill E; Harrington, Amanda T; Roberts, Marilyn C; Soge, Olusegun O; Maquelin, Kees
The anterior nares are the site of choice for the Veterans Administration methicillin-resistant Staphylococcus aureus (MRSA) surveillance program; however, a correlation between nares colonization and concomitant wound infections has not been well established. The purpose of this study was 3-fold: to determine the relatedness of MRSA isolates from 40 paired wound and nares specimens by four different strain typing methods, to determine concordance of typing methods, and to establish a baseline of MRSA types at this medical center. Isolates were typed by repetitive PCR (rep-PCR) (DiversiLab System; DL) and SpectraCell Raman analysis (SCRA) (commercially available methods that can be performed within a clinical lab), pulsed-field gel electrophoresis (PFGE), and an antibiotic susceptibility profile (AB). Whole-genome optical mapping (WGM) (OpGen, Inc.) was performed on selected isolates. All methods agreed that 26 pairs were indistinguishable and four pairs were different. Discrepant results were as follows: 4 where only SCRA was discordant, 3 where only AB was discordant, 2 where both DL and AB were discordant, and 1 where both DL and SCRA were discordant. All WGM agreed with PFGE. After discrepancy resolution, 80% of the pairs were indistinguishable and 20% were different. A total of 56% of nares results were nonpredictive if negative nares and positive wound cultures are included. Methods agreed 85 to 93% of the time; however, congruence of isolates to a clade was lower. Baseline analysis of types showed that 15 pairs were unique to single patients (30 strains, 38%; 47% of the matching pairs). Twenty-five strains (30%) represented a single clade identical by PFGE, SCRA, and DL, decreasing specificity. Typing method and institutional type frequency are important in assessing MRSA strain relatedness.
Duffes, F; Leroi, F; Boyaval, P; Dousset, X
Preservation of smoked salmon from bacterial spoilage, and especially from Listeria monocytogenes by bacteriocin producers is a promising challenge. Over a hundred lactic acid bacteria, isolated from commercial vacuum packaged cold smoked salmon, were screened for their antagonistic activity against L. innocua. Twenty-two strains were able to produce bacteriocin-like proteinaceous substances. These strains were characterized physiologically and biochemically as Carnobacterium strains. Three different groups were determined by pulsed-field gel electrophoresis after Sma I and Apa I DNA digestion. Peptidoglycan hydrolases patterns completed the characterization of these strains. All were confirmed as being Carnobacterium piscicola. Growth and bacteriocin production of three strains of each group and two well known bacteriocin producers (C. divergens V41 and C. piscicola V1) were tested in a simulated cold smoked fish system at 4 degrees C. These strains were able to reach 10(8) cfu ml(-1) in 21 days and to produce as much bacteriocin activities in the cold smoked fish system as in the rich media. Carnobacterium divergens V41 and C. piscicola V1 were the most effective strains in co-culture experiments, inhibiting L. monocytogenes as early as day 4, whereas C. piscicola SF668 inhibiting effect was observed at day 13. The potential for using such biopreservation treatments on whole smoked salmon is discussed.
Heir, E; Sundheim, G; Holck, A L
The complete nucleotide sequence of the 2.8 kb plasmid pST827 involved in resistance to the quaternary ammonium compound (QAC) benzalkonium chloride in meat-associated staphylococci was determined. An open reading frame (ORF) similar to the QAC resistance genes qacC, ebr and smr previously reported from clinical staphylococcal strains was identified (qacC'). In addition an ORF coding for a protein (Rep827) showing extensive homology to reported replication proteins of Gram-positive organisms was found. The occurrence of known QAC resistance gene (qacA-C) among staphylococcal strains isolated from food processing plants was studied by hybridization analysis. Of 191 isolates, 25 were resistant to benzalkonium chloride. Five of these gave no hybridization signals to probes specific for qacA-C. Further hybridization analysis indicated that pST827 or closely related plasmids are widespread among QAC-resistant staphylococcal strains. The finding of resistant staphylococci in different areas of the food processing industry indicates that QAC resistance is a potential problem in the food processing industry.
Azali, Muhammad Azharuddin; Yean Yean, Chan; Aminuddin Baki, Nurul Najian
The presence of pathogenic Leptospira spp. in the environment poses threats to human health. The aim of this study was to detect and characterize Leptospira spp. from environmental samples. A total of 144 samples comprised of 72 soil and 72 water samples were collected from markets and recreational areas in a north-eastern state in Malaysia. Samples were cultured on Ellinghausen and McCullough modified by Johnson and Harris media. Leptospires were positive in 22.9% (n = 33) of the isolates. Based on partial sequences of 16S rRNA, a pathogenic leptospire, Leptospira alstonii (n = 1/33), was identified in 3% of the isolates followed by intermediate leptospire (L. wolffii, n = 1/33, and L. licerasiae, n = 7/33) and nonpathogenic leptospire, L. meyeri (n = 22/33) in 24.2% and 66.7%, respectively. This study demonstrates the presence of a clinically significant pathogenic L. alstonii in the environments which could pose health risks to the occupants and visitors. PMID:27127522
Tamay-Cach, Feliciano; Correa-Basurto, José; Villa-Tanaca, Lourdes; Mancilla-Percino, Teresa; Juárez-Montiel, Margarita; Trujillo-Ferrara, José G
Three glutamic acid derivatives, two boron-containing and one imide-containing compound, were synthesized and tested for antimicrobial activity targeting glutamate-racemase. Antimicrobial effect was evaluated over Bacillus spp. Docking analysis shown that the test compounds bind near the active site of racemase isoforms, suggesting an allosteric effect. The boron derivatives had greater affinity than the imide derivative. In vitro assays shown good antimicrobial activity for the boron-containing compounds, and no effectiveness for the imide-containing compounds. The minimum inhibitory concentration of tetracycline, used as standard, was lower than that of the boron-containing derivatives. However, it seems that the boron-containing derivatives are more selective for bacteria. Experimental evidence suggests that the boron-containing derivatives act by inhibiting the racemase enzyme. Therefore, these test compounds probably impede the formation of the bacterial cell wall. Thus, the boron-containing glutamic acid derivatives should certainly be of interest for future studies as antimicrobial agents for Bacillus spp.
Kaiser, Michael; Gil, Joel; Treu, Ryan; Valdes, Jose; Davis, Stephen
Infections of acute and chronic wounds have a substantial negative impact on patient outcomes. Because bacterial resistance to traditional antimicrobials continues to increase, an in vitro study was conducted to examine current sensitivities of various methicillin-resistant and methicillin-sensitive strains of Staphylococcus aureus (MRSA and MSSA) to commonly used topical antimicrobial agents. Using fresh cultures of eight strains of MRSA and MSSA, the area of the zone of inhibition produced by various topical antimicrobials, including an aminoglycoside antibiotic, monocarboxylic acid antibiotic, pleuromutilin antibiotic, triple antibiotic ointment, and petrolatum ointment, was examined. Six culture plates per antimicrobial were prepared using the Kirby Bauer method; soy blood culture plates were inoculated with the bacteria, incubated for 24 hours at 37˚ C, and their zones of inhibition measured and calculated. Data were analyzed using ANOVA testing. Mupirocin treatment was the most effective antimicrobial, with areas of inhibition ranging from 30.34 cm2 to 61.70 cm2 (P <0.05), as compared to the next most effective, retapamulin, with areas of inhibition ranging from 11.97 cm2 to 23.54 cm2. This study provides current scientific data to help the development of a thoughtful rationale for the use of topical antimicrobials in wounds. Additional in vivo studies to substantiate these findings are needed.
Sakinc, Türkan; Kleine, Britta; Gatermann, Sören G
A gene encoding a serine-aspartate repeat protein of Staphylococcus saprophyticus, an important cause of urinary tract infections in young women, has been cloned and sequenced. In contrast to other SD repeat proteins, SdrI carries 21 additional N-terminal repeats with a consensus sequence of (P/A)ATKE(K/E)A(A/V)(T/I)(A/T/S)EE and has the longest SD(AD)(1-5) repetitive region (854 amino acids) described so far. This highly repetitive sequence contains only the amino acids serine, asparagine, and a distinctly greater amount of alanine (37%) than all other known SD repeat proteins (2.3 to 4.4%). In addition, it is a collagen-binding protein of S. saprophyticus and the second example in this organism of a surface protein carrying the LPXTG motif. We constructed an isogenic sdrI knockout mutant that showed decreased binding to immobilized collagen compared with wild-type S. saprophyticus strain 7108. Binding could be reconstituted by complementation. Collagen binding is specifically caused by SdrI, and the recently described UafA protein, the only LPXTG-containing protein in the genome sequence of the type strain, is not involved in this trait. Our experiments suggest that, as in other staphylococci, the presence of different LPXTG-anchored cell wall proteins is common in S. saprophyticus and support the notion that the presence of matrix-binding surface proteins is common in staphylococci.
Piechowicz, Lidia; Garbacz, Katarzyna; Budzyńska, Anna; Dąbrowska-Szponar, Maria
We describe an outbreak of bullous impetigo (BI) that occurred in a maternity unit and show phenotypic and genotypic properties and relatedness of isolated Staphylococcus aureus strains. Clinical material was obtained from 11 affected neonates. Additionally, nasal swabs from 67 healthy care workers (HCWs) as well as 107 environmental swabs were investigated. All isolates were screened for exfoliative toxin genes (eta, etb), antibiotic susceptibility and phage typed. Chromosomal DNA was genotyped by MLVF method and PCR/RFLP of coagulase gene were tested. Affected neonates were infected by two clusters of eta-positive S. aureus of phage type 3C/71: (1) MLVF type A isolates resistant only to penicillin, and (2) MLVF type B isolates resistant to penicillin and erythromycin/clindamycin. All isolates were susceptible to methicillin. We found 19 of 67 HCWs to be S. aureus nasal carriers. Two nasal isolates from HCWs were related to the outbreak on the basis of phage typing, PCR detection of eta/etb genes, antibiotyping and genotyping. Additionally, environmental swabs from the maternity unit revealed a 3C/71 S. aureus in the mattress of a baby bed. This is the first documented case of an outbreak of BI caused by phage type 3C/71 eta-positive strain of S. aureus.
Ben Bacha, Abir; Moubayed, Nadine Ms; Al-Assaf, Alaa
In this study, a new strain, ALA1, was identified as Staphylococcus aureus by biochemical tests, and its 16S ribosomal DNA sequence was isolated from dromedary milk. ALA1 lipase production was optimized in shake flask experiments and measured with varying pH (3-11), temperature (20-55 °C) and substrate concentrations. The maximum lipase production was recorded at pH 8 and 30 °C for up to 30 H of culture period for the S. aureus ALA1 strain. Among the substrates tested, selected carbon sources, xylose, nitrogen source, yeast extract, and olive oil (1%) were suitable for maximizing lipase production. The effects of surfactants were investigated and showed that Tween 20, Tween 80, and Triton X-100 prevented lipase production. Interestingly, isolate ALA1 was able to grow in high concentrations of benzene or toluene (up to 50% (v/v)). Moreover, the lipolytic activity of the S. aureus ALA1 lipase was stimulated by diethyl ether, whereas almost 100% of S. aureus ALA1 lipase activity was retained in 25% acetone, acetonitrile, benzene, 2-propanol, ethanol, methanol, or toluene. Because of its stability in organic solvent, the S. aureus ALA1 lipase was used as a biocatalyst to synthesize high levels of added value molecules. S. aureus ALA1 lipase could be considered as an ideal choice for applications in detergent formulations because of its high stability and compatibility with various surfactants, oxidizing agents, and commercial detergents.
Zeaki, Nikoleta; Susilo, Yusak Budi; Pregiel, Anna; Rådström, Peter; Schelin, Jenny
The present study investigates the nature of the link between the staphylococcal enterotoxin A (SEA) gene and the lifecycle of Siphoviridae bacteriophages, including the origin of strain variation regarding SEA production after prophage induction. Five strains representing three different genetic lines of the sea region were studied under optimal and prophage-induced growth conditions and the Siphoviridae lifecycle was followed through the phage replicative form copies and transcripts of the lysogenic repressor, cro. The role of SOS response on prophage induction was addressed through recA transcription in a recA-disruption mutant. Prophage induction was found to increase the abundance of the phage replicative form, the sea gene copies and transcripts and enhance SEA production. Sequence analysis of the sea regions revealed that observed strain variances were related to strain capacity for prophage induction, rather than sequence differences in the sea region. The impact of SOS response activation on the phage lifecycle was demonstrated by the absence of phage replicative form copies in the recA-disruption mutant after prophage induction. From this study it emerges that all aspects of SEA-producing strain, the Siphoviridae phage and the food environment must be considered when evaluating SEA-related hazards.
Quecine, Maria Carolina; Kidarsa, Teresa A; Goebel, Neal C; Shaffer, Brenda T; Henkels, Marcella D; Zabriskie, T Mark; Loper, Joyce E
Pseudomonas protegens strain Pf-5 is a rhizosphere bacterium that suppresses soilborne plant diseases and produces at least seven different secondary metabolites with antifungal properties. We derived mutants of Pf-5 with single and multiple mutations in biosynthesis genes for seven antifungal metabolites: 2,4-diacetylphoroglucinol (DAPG), pyrrolnitrin, pyoluteorin, hydrogen cyanide, rhizoxin, orfamide A, and toxoflavin. These mutants were tested for inhibition of the pathogens Fusarium verticillioides and Fusarium oxysporum f. sp. pisi. Rhizoxin, pyrrolnitrin, and DAPG were found to be primarily responsible for fungal antagonism by Pf-5. Previously, other workers showed that the mycotoxin fusaric acid, which is produced by many Fusarium species, including F. verticillioides, inhibited the production of DAPG by Pseudomonas spp. In this study, amendment of culture media with fusaric acid decreased DAPG production, increased pyoluteorin production, and had no consistent influence on pyrrolnitrin or orfamide A production by Pf-5. Fusaric acid also altered the transcription of biosynthetic genes, indicating that the mycotoxin influenced antibiotic production by Pf-5 at the transcriptional level. Addition of fusaric acid to the culture medium reduced antibiosis of F. verticillioides by Pf-5 and derivative strains that produce DAPG but had no effect on antibiosis by Pf-5 derivatives that suppressed F. verticillioides due to pyrrolnitrin or rhizoxin production. Our results demonstrated the importance of three compounds, rhizoxin, pyrrolnitrin, and DAPG, in suppression of Fusarium spp. by Pf-5 and confirmed that an interspecies signaling system mediated by fusaric acid had parallel effects on antifungal metabolite production and antibiosis by the bacterial biological control organism.
Quecine, Maria Carolina; Kidarsa, Teresa A.; Goebel, Neal C.; Shaffer, Brenda T.; Henkels, Marcella D.; Zabriskie, T. Mark
Pseudomonas protegens strain Pf-5 is a rhizosphere bacterium that suppresses soilborne plant diseases and produces at least seven different secondary metabolites with antifungal properties. We derived mutants of Pf-5 with single and multiple mutations in biosynthesis genes for seven antifungal metabolites: 2,4-diacetylphoroglucinol (DAPG), pyrrolnitrin, pyoluteorin, hydrogen cyanide, rhizoxin, orfamide A, and toxoflavin. These mutants were tested for inhibition of the pathogens Fusarium verticillioides and Fusarium oxysporum f. sp. pisi. Rhizoxin, pyrrolnitrin, and DAPG were found to be primarily responsible for fungal antagonism by Pf-5. Previously, other workers showed that the mycotoxin fusaric acid, which is produced by many Fusarium species, including F. verticillioides, inhibited the production of DAPG by Pseudomonas spp. In this study, amendment of culture media with fusaric acid decreased DAPG production, increased pyoluteorin production, and had no consistent influence on pyrrolnitrin or orfamide A production by Pf-5. Fusaric acid also altered the transcription of biosynthetic genes, indicating that the mycotoxin influenced antibiotic production by Pf-5 at the transcriptional level. Addition of fusaric acid to the culture medium reduced antibiosis of F. verticillioides by Pf-5 and derivative strains that produce DAPG but had no effect on antibiosis by Pf-5 derivatives that suppressed F. verticillioides due to pyrrolnitrin or rhizoxin production. Our results demonstrated the importance of three compounds, rhizoxin, pyrrolnitrin, and DAPG, in suppression of Fusarium spp. by Pf-5 and confirmed that an interspecies signaling system mediated by fusaric acid had parallel effects on antifungal metabolite production and antibiosis by the bacterial biological control organism. PMID:26655755
Tak, Nisha; Awasthi, Esha; Bissa, Garima; Meghwal, Raju Ram; James, Euan K; Sprent, Janet S; Gehlot, Hukam S
Phylogenetically diverse Ensifer strains associated with five species of Tephrosia growing in alkaline soils of semi-arid regions of the Thar Desert were characterized using multi locus sequence analysis. Based on 16S rRNA and four protein-coding housekeeping gene (recA, atpD, glnII and dnaK) sequences, the Tephrosia-Ensifer strains were genetically different from the type strains of Ensifer saheli, Ensifer kostiensis, Ensifer terangae (African origin) and Ensifer psoraleae (Asiatic origin). One strain, Ensifer sp. TL4, showed maximum similarity (99%) to Ensifer adhaerens LMG 20216(T) and formed a separate lineage close to it. Phylogenetic incongruence between sym and housekeeping genes was observed. The monophyletic origin of symbiotic genes from Asia in the Tephrosia-Ensifer strains from the Thar Desert suggests that they might have been acquired from a common ancestor and horizontally transferred. These novel strains are promiscuous, cross-nodulating some papilionoid crop species, mimosoid trees and the caesalpinioid Chamaecrista pumila. This study improves understanding of the distribution of Ensifer in unexplored and threatened alkaline arid regions of the Thar Desert and how this relates to other similar regions in the world.
Walochnik, J; Obwaller, A; Aspöck, H
Various species of the genus Acanthamoeba have been described as potential pathogens; however, differentiation of acanthamoebae remains problematic. The genus has been divided into 12 18S rDNA sequence types, most keratitis causing strains exhibiting sequence type T4. We recently isolated a keratitis causing Acanthamoeba strain showing sequence type T6, but being morphologically identical to a T4 strain. The aim of our study was to find out, whether the 18S rDNA sequence based identification correlates to immunological differentiation. The protein and antigen profiles of the T6 isolate and three reference Acanthamoeba strains were investigated using two sera from Acanthamoeba keratitis patients and one serum from an asymptomatic individual. It was shown, that the T6 strain produces a distinctly different immunological pattern, while patterns within T4 were identical. Affinity purified antibodies were used to further explore immunological cross-reactivity between sequence types. Altogether, the results of our study support the Acanthamoeba 18S rDNA sequence type classification in the investigated strains.
Suzuki, Takashi; Yamamoto, Toshihiro; Kaito, Chikara; Miyamoto, Hitoshi; Ohashi, Yuichi
Staphylococcus aureus is a predominant pathogen in keratitis, and the rate of methicillin-resistant S. aureus (MRSA) is increasing. In our previous study, genotypes of MRSA isolates from keratitis cases were classified into ST5 or ST764 lineage by multi-locus sequence typing. In this study, we examined the virulence properties of these MRSA keratitis isolates and its virulence determinants. There was no difference in the prevalence of virulence genes, such as adhesion and toxins, between ST5 and ST764 isolates. All ST5 isolates carried the intact psm-mec gene, which suppresses exotoxin production and colony spreading, but promotes biofilm formation. In contrast, all ST764 isolates had one point mutation in the psm-mec gene. Biofilm production in ST5 isolates was significantly higher than that in ST764 isolates, whereas colony spreading, hemolytic activity, and production of alpha-phenol-soluble modulins were higher in ST764 than in ST5 isolates. The toxicity of ST764 supernatants to corneal epithelial cells was higher than that of ST5 supernatants. These results suggest that the point mutation in the psm-mec gene contributes to the difference in virulence properties between ST5 and ST764 isolates in MRSA keratitis.
Lührmann, Anne; Matthes, Rutger; Kramer, Axel
Zielsetzung: Die antimikrobielle Wirksamkeit von kaltem Atmosphärendruckplasma (CAP), auch als gewebeverträgliches Plasma (TTP) bezeichnet, könnte eine aussichtsreiche Option zur Eradikation von Methicillin-empfindlichen ebenso wie von Methicillin-resistenten Staphylococcus aureus-Stämmen sein, die oft chronische Wunden kolonisieren. Bisher wurde der Einfluss von CAP auf die Antibiotikaempfindlichkeit von S. aureus kaum untersucht. Da eine Veränderung der Antibiotikaempfindlichkeit für die Wundbehandlung relevant sein könnte, sollte der Einfluss von CAP auf die Empfindlichkeit verschiedener S. aureus-Stämme gegen unterschiedliche Antibiotika untersucht werden.Methode: Im Agardiffusionstest wurden Antibiotikatestplättchen mit Cefuroxim, Gentamicin, Oxacillin, Vancomycin, Ciprofloxacin, Co-Trimoxazol, Clindamycin und Erythromycin eingesetzt. Die Teststämme wurden auf Agar ausplattiert und mit CAP exponiert, bevor die Testplättchen aufgelegt wurden. Nach 24 h Bebrütung wurden die Inhibitionszonen gemessen und statistisch auf Unterschiede geprüft.Ergebnisse: In den meisten Fällen war die Einfluss von CAP auf die Antibiotikaempfindlichkeit zu vernachlässigen. Für zwei Stämme wurde die Empfindlichkeit gegenüber β-Lactam-Antibiotika signifikant herabgesetzt. Schlussfolgerung: Da CAP die Antibiotikaempfindlichkeit beeinflussen kann, sollten vor beabsichtigter kombinierter lokaler CAP-Behandlung und gleichzeitiger systemischer Antibiotikagabe Interaktionen in vitro untersucht werden, um unerwünschte Kombinationseffekte auszuschließen.
Di Gregorio, Sabrina; Fernandez, Silvina; Cuirolo, Arabela; Verlaine, Olivier; Amoroso, Ana; Mengin-Lecreulx, Dominique; Famiglietti, Angela; Joris, Bernard; Mollerach, Marta
The aim of this study is to characterize the factors related to peptidoglycan metabolism in isogenic hVISA/VISA ST100 strains. Recently, we reported the increase in IS256 transposition in invasive hVISA ST100 clinical strains isolated from the same patient (D1 and D2) before and after vancomycin treatment and two laboratory VISA mutants (D23C9 and D2P11) selected from D2 in independent experiments. High performance liquid chromatography-mass spectrometry (HPLC-MS) analysis of peptidoglycan muropeptides showed increased proportion of monomeric muropeptides and a concomitant decrease in the proportion of tetrameric muropeptide in D2 and derived mutants when compared to the original strain D1. In addition, strain D2 and its derived mutants showed an increase in cell wall thickness with increased pbp2 gene expression. The VISA phenotype was not stable in D2P11 and showed a reduced autolysis profile. On the other hand, the mutant D23C9 differentiates from D2 and D2P11 in the autolysis profile, and pbp4 transcription profile. D2-derived mutants exhibited differences in the susceptibility to other antimicrobials. Our results highlight the possibility of selection of different VISA phenotypes from a single hVISA-ST100 genetic background.
Di Gregorio, Sabrina; Fernandez, Silvina; Cuirolo, Arabela; Verlaine, Olivier; Amoroso, Ana; Mengin-Lecreulx, Dominique; Famiglietti, Angela; Joris, Bernard
The aim of this study is to characterize the factors related to peptidoglycan metabolism in isogenic hVISA/VISA ST100 strains. Recently, we reported the increase in IS256 transposition in invasive hVISA ST100 clinical strains isolated from the same patient (D1 and D2) before and after vancomycin treatment and two laboratory VISA mutants (D23C9 and D2P11) selected from D2 in independent experiments. High performance liquid chromatography-mass spectrometry (HPLC-MS) analysis of peptidoglycan muropeptides showed increased proportion of monomeric muropeptides and a concomitant decrease in the proportion of tetrameric muropeptide in D2 and derived mutants when compared to the original strain D1. In addition, strain D2 and its derived mutants showed an increase in cell wall thickness with increased pbp2 gene expression. The VISA phenotype was not stable in D2P11 and showed a reduced autolysis profile. On the other hand, the mutant D23C9 differentiates from D2 and D2P11 in the autolysis profile, and pbp4 transcription profile. D2-derived mutants exhibited differences in the susceptibility to other antimicrobials. Our results highlight the possibility of selection of different VISA phenotypes from a single hVISA-ST100 genetic background. PMID:27991847
Penyalver, Ramón; Oger, Philippe; López, María M.; Farrand, Stephen K.
Iron-binding compounds were produced in various amounts in response to iron starvation by a collection of Agrobacterium strains belonging to the species A. tumefaciens, A. rhizogenes, and A. vitis. The crown gall biocontrol agent A. rhizogenes strain K84 produced a hydroxamate iron chelator in large amounts. Production of this compound, and also of a previously described antibiotic-like substance called ALS84, occurred only in cultures of strain K84 grown in iron-deficient medium. Similarly, sensitivity to ALS84 was expressed only when susceptible cells were tested in low-iron media. Five independent Tn5-induced mutants of strain K84 affected in the production of the hydroxamate iron chelator showed a similar reduction in the production of ALS84. One of these mutants, M8-10, was completely deficient in the production of both agents and grew poorly compared to the wild type under iron-limiting conditions. Thus, the hydroxamate compound has siderophore activity. A 9.1-kb fragment of chromosomal DNA containing the Tn5 insertion from this mutant was cloned and marker exchanged into wild-type strain K84. The homogenote lost the ability to produce the hydroxamate siderophore and also ALS84. A cosmid clone was isolated from a genomic library of strain K84 that restored to strain M8-10 the ability to produce of the siderophore and ALS84, as well as growth in iron-deficient medium. This cosmid clone contained the region in which Tn5 was located in the mutant. Sequence analysis showed that the Tn5 insert in this mutant was located in an open reading frame coding for a protein that has similarity to those of the gramicidin S synthetase repeat superfamily. Some such proteins are required for synthesis of hydroxamate siderophores by other bacteria. Southern analysis revealed that the biosynthetic gene from strain K84 is present only in isolates of A. rhizogenes that produce hydroxamate-type compounds under low-iron conditions. Based on physiological and genetic analyses showing
Emaneini, Mohammad; Khoramrooz, Seyed Sajjad; Shahsavan, Shadi; Dabiri, Hossein; Jabalameli, Fereshteh
Adenoids as a first line of host defense against respiratory microbes play an important role in majority of upper airway infectious and noninfectious illnesses. Bacterial pathogen can colonize on the adenoid tissue and probably act as a reservoir for them. To determine phenotypic and genotypic characterization of biofilm forming capacity of Staphylococcus aureus isolates from children with adenoid hypertrophy and prevalence of Panton-Valentine leukocidin (PVL) gene we collected 17 consecutive, clinically significant S. aureus isolates from children with adenoid hypertrophy undergoing adenoidectomy with one or more of the upper airway obstruction symptoms, nasal obstruction, mouth breathing, snoring, or sleep apnea. Biofilm formation was evaluated by colorimetric microtiter plate's assay. Gene encoding PVL and adhesion- or biofilm formation-encoding genes were targeted by polymerase chain reaction (PCR) assay. According to the results, all strains produced biofilm. Seven (41.2%) isolates produced strong biofilm whereas 7 (41.2%) isolates produced week and 3 (17.6%) isolates produced medium biofilm. Regarding the adhesion- or biofilm formation-encoding genes, 16 (94.1%) isolates were positive for the gene eno, 13(76.4%) for icaA, 13 (76.4%) for icaD, 10 (58.8%) for fib, 10 (58.8%) for fnbB, 4(23.5%) for can, and 1(5.8%) for fnbA. The high prevalence of genes encoding biofilms and adhesins and phenotypic ability to form a biofilm by S. aureus strains emphasizes the pathogenic character of strains isolated from children with adenoid hypertrophy.
Albrecht, Valerie S; Limbago, Brandi M; Moran, Gregory J; Krishnadasan, Anusha; Gorwitz, Rachel J; McDougal, Linda K; Talan, David A
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is a prevalent cause of skin and soft tissue infections (SSTI), but the association between CA-MRSA colonization and infection remains uncertain. We studied the carriage frequency at several body sites and the diversity of S. aureus strains from patients with and without SSTI. Specimens from the nares, throat, rectum, and groin of case subjects with a closed skin abscess (i.e., without drainage) and matched control subjects without a skin infection (n = 147 each) presenting to 10 U.S. emergency departments were cultured using broth enrichment; wound specimens were cultured from abscess cases. Methicillin resistance testing and spa typing were performed for all S. aureus isolates. S. aureus was found in 85/147 (57.8%) of abscesses; 49 isolates were MRSA, and 36 were methicillin-susceptible S. aureus (MSSA). MRSA colonization was more common among cases (59/147; 40.1%) than among controls (27/147; 18.4%) overall (P < 0.001) and at each body site; no differences were observed for MSSA. S. aureus-infected subjects were usually (75/85) colonized with the infecting strain; among MRSA-infected subjects, this was most common in the groin. The CC8 lineage accounted for most of both infecting and colonizing isolates, although more than 16 distinct strains were identified. Nearly all MRSA infections were inferred to be USA300. There was more diversity among colonizing than infecting isolates and among those isolated from controls versus cases. CC8 S. aureus is a common colonizer of persons with and without skin infections. Detection of S. aureus colonization, and especially MRSA, may be enhanced by extranasal site culture.
Al Dahouk, Sascha; Köhler, Stephan; Occhialini, Alessandra; Jiménez de Bagüés, María Pilar; Hammerl, Jens Andre; Eisenberg, Tobias; Vergnaud, Gilles; Cloeckaert, Axel; Zygmunt, Michel S.; Whatmore, Adrian M.; Melzer, Falk; Drees, Kevin P.; Foster, Jeffrey T.; Wattam, Alice R.; Scholz, Holger C.
Twenty-one small Gram-negative motile coccobacilli were isolated from 15 systemically diseased African bullfrogs (Pyxicephalus edulis), and were initially identified as Ochrobactrum anthropi by standard microbiological identification systems. Phylogenetic reconstructions using combined molecular analyses and comparative whole genome analysis of the most diverse of the bullfrog strains verified affiliation with the genus Brucella and placed the isolates in a cluster containing B. inopinata and the other non-classical Brucella species but also revealed significant genetic differences within the group. Four representative but molecularly and phenotypically diverse strains were used for in vitro and in vivo infection experiments. All readily multiplied in macrophage-like murine J774-cells, and their overall intramacrophagic growth rate was comparable to that of B. inopinata BO1 and slightly higher than that of B. microti CCM 4915. In the BALB/c murine model of infection these strains replicated in both spleen and liver, but were less efficient than B. suis 1330. Some strains survived in the mammalian host for up to 12 weeks. The heterogeneity of these novel strains hampers a single species description but their phenotypic and genetic features suggest that they represent an evolutionary link between a soil-associated ancestor and the mammalian host-adapted pathogenic Brucella species. PMID:28300153
Evangelopoulou, Grammato; Filioussis, Georgios; Kritas, Spyridon; Kantere, Maria; Burriel, Angeliki R
The presence of Gram-negative bacteria species, other than Salmonella spp., in the gallbladder of pigs was examined. Isolated Gram-negative bacteria were assigned to species using the Microgen™ GnA+B-ID Systems. Of the 64 isolated strains 43 were identified as Escherichia coli, seven as Enterobacter spp., three each as Klebsiella spp., Citrobacterfreundii, Aeromonas hydrophila and Cronobacter sakazakii and one each as Escherichiafergusonii and Trabulsiella guamensis. Their antibiograms showed very high resistance to ampicillin, amoxicillin, tetracycline, chloramphenicol and sulfamethoxazole/trimethoprim. It was concluded that the pigs' gallbladder is a reservoir of potentially pathogenic Gram-negative bacteria for pork consumers.
Foster, Timothy J
There has been some debate about the disease-invoking potential of Staphylococcus aureus strains and whether invasive disease is associated with particularly virulent genotypes, or "superbugs." A study in this issue of the JCI describes the genotyping of a large collection of nonclinical, commensal S. aureus strains from healthy individuals in a Dutch population. Extensive study of their genetic relatedness by amplified restriction fragment typing and comparison with strains that are associated with different types of infections revealed that the S. aureus population is clonal and that some strains have enhanced virulence. This is discussed in the context of growing interest in the mechanisms of bacterial colonization, antibiotic resistance, and novel vaccines.
Ciok, Anna; Adamczuk, Marcin; Bartosik, Dariusz; Dziewit, Lukasz
Pseudomonas strains isolated from the heavily contaminated Lubin copper mine and Zelazny Most post-flotation waste reservoir in Poland were screened for the presence of integrons. This analysis revealed that two strains carried homologous DNA regions composed of a gene encoding a DNA_BRE_C domain-containing tyrosine recombinase (with no significant sequence similarity to other integrases of integrons) plus a three-component array of putative integron gene cassettes. The predicted gene cassettes encode three putative polypeptides with homology to (i) transmembrane proteins, (ii) GCN5 family acetyltransferases, and (iii) hypothetical proteins of unknown function (homologous proteins are encoded by the gene cassettes of several class 1 integrons). Comparative sequence analyses identified three structural variants of these novel integron-like elements within the sequenced bacterial genomes. Analysis of their distribution revealed that they are found exclusively in strains of the genus Pseudomonas.
Zanetti, Stefania; Cannas, Sara; Molicotti, Paola; Bua, Alessandra; Cubeddu, Marina; Porcedda, Silvia; Marongiu, Bruno; Sechi, Leonardo Antonio
Mycobacterium tuberculosis is the etiological agent of tuberculosis. The World Health Organization has estimated that 8 million of people develop active TB every year and the situation is complicated by an increase of Mycobacterium tuberculosis strains resistant to drugs used in antitubercular therapy: MDR and XDR-TB. Myrtle leaf extracts, used as an antiseptic in Sardinian traditional medicine, have strong antibacterial activity as several investigations showed. In this study we investigated the antimicrobial properties of the essential oil of Myrtus communis against clinical strains of M. tuberculosis and M. paratuberculosis. PMID:20706606
Zanetti, Stefania; Cannas, Sara; Molicotti, Paola; Bua, Alessandra; Cubeddu, Marina; Porcedda, Silvia; Marongiu, Bruno; Sechi, Leonardo Antonio
Mycobacterium tuberculosis is the etiological agent of tuberculosis. The World Health Organization has estimated that 8 million of people develop active TB every year and the situation is complicated by an increase of Mycobacterium tuberculosis strains resistant to drugs used in antitubercular therapy: MDR and XDR-TB. Myrtle leaf extracts, used as an antiseptic in Sardinian traditional medicine, have strong antibacterial activity as several investigations showed. In this study we investigated the antimicrobial properties of the essential oil of Myrtus communis against clinical strains of M. tuberculosis and M. paratuberculosis.
Rolain, Jean-Marc; François, Patrice; Hernandez, David; Bittar, Fadi; Richet, Hervé; Fournous, Ghislain; Mattenberger, Yves; Bosdure, Emmanuelle; Stremler, Nathalie; Dubus, Jean-Christophe; Sarles, Jacques; Reynaud-Gaubert, Martine; Boniface, Stephanie; Schrenzel, Jacques; Raoult, Didier
Background Staphylococcus aureus is a major human pathogen responsible for a variety of nosocomial and community-acquired infections. Recent reports show that the prevalence of Methicillin-Resistant S. aureus (MRSA) infections in cystic fibrosis (CF) patients is increasing. In 2006 in Marseille, France, we have detected an atypical MRSA strain with a specific antibiotic susceptibility profile and a unique growth phenotype. Because of the clinical importance of the spread of such strain among CF patients we decided to sequence the genome of one representative isolate (strain CF-Marseille) to compare this to the published genome sequences. We also conducted a retrospective epidemiological analysis on all S. aureus isolated from 2002 to 2007 in CF patients from our institution. Results CF-Marseille is multidrug resistant, has a hetero-Glycopeptide-Intermediate resistance S. aureus phenotype, grows on Cepacia agar with intense orange pigmentation and has a thickened cell wall. Phylogenetic analyses using Complete Genome Hybridization and Multi Locus VNTR Assay showed that CF-Marseille was closely related to strain Mu50, representing vancomycin-resistant S. aureus. Analysis of CF-Marseille shows a similar core genome to that of previously sequenced MRSA strains but with a different genomic organization due to the presence of specific mobile genetic elements i.e. a new SCCmec type IV mosaic cassette that has integrated the pUB110 plasmid, and a new phage closely related to phiETA3. Moreover this phage could be seen by electron microscopy when mobilized with several antibiotics commonly used in CF patients including, tobramycin, ciprofloxacin, cotrimoxazole, or imipenem. Phylogenetic analysis of phenotypically similar h-GISA in our study also suggests that CF patients are colonized by polyclonal populations of MRSA that represents an incredible reservoir for lateral gene transfer. Conclusion In conclusion, we demonstrated the emergence and spreading of a new isolate of
Merghni, Abderrahmen; Dallel, Ines; Noumi, Emira; Kadmi, Yassine; Hentati, Hajer; Tobji, Samir; Ben Amor, Adel; Mastouri, Maha
Biosurfactants also called bioemulsifiers are amphipathic compounds produced by many microorganisms that allow them to exhibit a wide range of biological activities. The aim of this study was to determine the antioxidant and antiproliferative potential of biosurfactants isolated from Lactobacillus casei and to assess their anti-adhesive and anti-biofilm abilities against oral opportunistic Staphylococcus aureus strains. The antioxidant activity of biosurfactant was evaluated using the in vitro scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. The antiproliferative activity was determined on epithelial cell line (HEp-2) by the Methylthiazole tetrazolium (MTT) reduction assay. The anti-adhesive and antibiofilm activity against S. aureus strains were achieved using crystal violet staining. Our results revealed that the DPPH scavenging activity of biosurfactants at 5.0 mg/mL concentration is between 74.6 and 77.3%. Furthermore, biosurfactants showed antiproliferative potency against studied epithelial cells as judged by IC50 and its value ranged from 109.1 ± 0.84 mg/mL to 129.7 ± 0.52 mg/mL. The results of the growth inhibition indicate that biosurfactant BS-LBl was more effective against oral S. aureus strains 9P and 29P with an IC50 of 1.92 ± 0.26 mg/mL and 2.16 ± 0.12 mg/mL respectively. Moreover, both biosurfactants displayed important antibiofilm activity with eradication percentages ranging from 80.22 ± 1.33% to 86.21 ± 2.94% for the BS-LBl, and from 53.38 ± 1.77% to 64.42 ± 2.09% for the BS-LZ9. Our findings demonstrate that biosurfactants from L. casei strains exhibited considerable antioxidant and antiproliferative potencies and were able to inhibit oral S. aureus strains with important antibiofilm efficacy. They could have a promising role in the prevention of oral diseases.
Hokai, Yozane; Jurkowicz, Boruch; Fernández-Gallardo, Jacob; Zakirkhodjaev, Nuruddinkodja; Sanaú, Mercedes; Muth, Theodore R.; Contel, María
A series of new heterometallic gold(I) thiolates containing ferrocenyl-phoshines were synthesized. Their antimicrobial properties were studied and compared to that of FDA-approved drug, auranofin (Ridaura), prescribed for the treatment of rheumatoid arthritis. MIC in the order of one digit micromolar were found for most of the compounds against Gram-positive bacteria S. aureus and CA MRSA strains US300 and US400. Remarkably, auranofin inhibited S. aureus, US300 and US400 in the order of 150–300 nM. This is the first time that the potent inhibitory effect of auranofin on MRSA strains has been described. The effects of a selected heterometallic compound and auranofin were also studied in a non-tumorigenic human embryonic kidney cell line (HEK-293). PMID:24935090
Zalila-Kolsi, Imen; Ben Mahmoud, Afif; Ali, Hacina; Sellami, Sameh; Nasfi, Zina; Tounsi, Slim; Jamoussi, Kaïs
Bacillus species are attractive due to their potential use in the biological control of fungal diseases. Bacillus amyloliquefaciens strain BLB369, Bacillus subtilis strain BLB277, and Paenibacillus polymyxa strain BLB267 were isolated and identified using biochemical and molecular (16S rDNA, gyrA, and rpoB) approaches. They could produce, respectively, (iturin and surfactin), (surfactin and fengycin), and (fusaricidin and polymyxin) exhibiting broad spectrum against several phytopathogenic fungi. In vivo examination of wheat seed germination, plant height, phenolic compounds, chlorophyll, and carotenoid contents proved the efficiency of the bacterial cells and the secreted antagonist activities to protect Tunisian durum wheat (Triticum turgidum L. subsp. durum) cultivar Om Rabiia against F. graminearum fungus. Application of single bacterial culture medium, particularly that of B. amyloliquefaciens, showed better protection than combinations of various culture media. The tertiary combination of B. amyloliquefaciens, B. subtilis, and P. polymyxa bacterial cells led to the highest protection rate which could be due to strains synergistic or complementary effects. Hence, combination of compatible biocontrol agents could be a strategic approach to control plant diseases.
Farasin, Julien; Koechler, Sandrine; Varet, Hugo; Deschamps, Julien; Dillies, Marie-Agnès; Proux, Caroline; Erhardt, Mathieu; Huber, Aline; Jagla, Bernd; Briandet, Romain; Coppée, Jean-Yves; Arsène-Ploetze, Florence
Bacteria of the genus Thiomonas are found ubiquitously in arsenic contaminated waters such as acid mine drainage (AMD), where they contribute to the precipitation and the natural bioremediation of arsenic. In these environments, these bacteria have developed a large range of resistance strategies among which the capacity to form particular biofilm structures. The biofilm formation is one of the most ubiquitous adaptive response observed in prokaryotes to various stresses, such as those induced in the presence of toxic compounds. This study focused on the process of biofilm formation in three Thiomonas strains (CB1, CB2 and CB3) isolated from the same AMD. The results obtained here show that these bacteria are all capable of forming biofilms, but the architecture and the kinetics of formation of these biofilms differ depending on whether arsenite is present in the environment and from one strain to another. Indeed, two strains favoured biofilm formation, whereas one favoured motility in the presence of arsenite. To identify the underlying mechanisms, the patterns of expression of some genes possibly involved in the process of biofilm formation were investigated in Thiomonas sp. CB2 in the presence and absence of arsenite, using a transcriptomic approach (RNA-seq). The findings obtained here shed interesting light on how the formation of biofilms, and the motility processes contribute to the adaptation of Thiomonas strains to extreme environments.
Background Pure bacterial strains give better yields when producing H2 than mixed, natural communities. However the main drawback with the pure cultures is the need to perform the fermentations under sterile conditions. Therefore, H2 production using artificial co-cultures, composed of well characterized strains, is one of the directions currently undertaken in the field of biohydrogen research. Results Four pure Clostridium cultures, including C. butyricum CWBI1009, C. pasteurianum DSM525, C. beijerinckii DSM1820 and C. felsineum DSM749, and three different co-cultures composed of (1) C. pasteurianum and C. felsineum, (2) C. butyricum and C. felsineum, (3) C. butyricum and C. pasteurianum, were grown in 20 L batch bioreactors. In the first part of the study a strategy composed of three-culture sequences was developed to determine the optimal pH for H2 production (sequence 1); and the H2-producing potential of each pure strain and co-culture, during glucose (sequence 2) and starch (sequence 3) fermentations at the optimal pH. The best H2 yields were obtained for starch fermentations, and the highest yield of 2.91 mol H2/ mol hexose was reported for C. butyricum. By contrast, the biogas production rates were higher for glucose fermentations and the highest value of 1.5 L biogas/ h was observed for the co-culture (1). In general co-cultures produced H2 at higher rates than the pure Clostridium cultures, without negatively affecting the H2 yields. Interestingly, all the Clostridium strains and co-cultures were shown to utilize lactate (present in a starch-containing medium), and C. beijerinckii was able to re-consume formate producing additional H2. In the second part of the study the co-culture (3) was used to produce H2 during 13 days of glucose fermentation in a sequencing batch reactor (SBR). In addition, the species dynamics, as monitored by qPCR (quantitative real-time PCR), showed a stable coexistence of C. pasteurianum and C. butyricum during this
Buxton, Thomas B; Travis, Michael T; O'Shea, Kevin J; McPherson, James C; Harvey, Steven B; Plowman, Kent M; Walsh, Douglas S
Animal models of post-traumatic acute osteomyelitis (OM) that closely mimic human scenarios, including infection prophylactic procedures such as debridement and lavage, may provide a better understanding of OM. We contaminated mechanically traumatized rat tibiae (n = 69) with various doses of a Staphylococcus aureus strain (SMH) known to cause human OM and then performed curettage and lavage. Tibiae were harvested 24 h after lavage for assessment of bacterial load and determination of minimal infective doses for 50% (ID50) and 95% (ID95) of rats. Some experiments varied tibial harvest time after lavage (n = 10); for progressive infection, tibiae were evaluated at 7 and 15 days after contamination (n = 17 for each time point). At 24 h after contamination, the ID50 was 1.8 x 10(3) CFU, and the ID95 was 9.2 x 10(3) CFU. Tibial bacterial loads did not increase with inocula greater than the ID95. Lavage removed many bacteria from bone, but it did not prevent subsequent infection or disease. At 15 days after contamination, most tibiae (14 of 17) were infected, with macroscopic and radiological signs of established OM. This newly described rat OM model, with a low ID95 despite prophylactic curettage and lavage, closely mimics events in contaminated human bone injuries. This situation will allow study of early factors in contaminated bone injuries, including clinical interventions that may reduce infection and prevent disease.
Khrustalev, Vladislav Victorovich; Ghaznavi-Rad, Ehsanollah; Neela, Vasanthakumari; Shamsudin, Mariana-Nor; Amouzandeh-Nobaveh, Alireza; Barkovsky, Eugene Victorovich
Fifteen sequences with stop codons have been obtained in the course of standard methicillin-resistant Staphylococcus aureus (MRSA) spa typing. In nine of those sequences, stop codons occurred due to nonsense G-T and A-T transversions. G-T transversions would appear to be frequent in the spa gene, mostly due to symmetric mutational AT-pressure in the whole S. aureus genome and due to replication-associated mutational pressure characteristic of lagging strands of the "chromosome". A-T transversions would appear to be frequent in the spa gene mostly due to transcription-associated mutational pressure. Relative to other S. aureus genes, short repeats in spa are enriched by nonsense sites for G-T and A-T transversions; the probability of being nonsense for A-T transversion is high in that part of spa coding region. 13 out of 15 (87%) of the sequences with stop codons were obtained from strains isolated from patients with generalized S. aureus infection. Truncation of spa at its C-terminus is predicted to result in a protein that possesses functional IgG binding domains unable to be linked to the cell wall. This is discussed in light of the known fact that extracellular spa is a strong virulence factor involved in immune evasion.
Serrano-Rodríguez, J M; Cárceles-García, C; Cárceles-Rodríguez, C M; Gabarda, M L; Serrano-Caballero, J M; Fernández-Varón, E
Minimum inhibitory concentration (MIC) and mutant prevention concentration (MPC) of veterinary fluoroquinolones as enrofloxacin, its metabolite ciprofloxacin, danofloxacin, difloxacin and marbofloxacin against Staphylococcus aureus strains (n=24) isolated from milk of sheep and goats affected by clinical mastitis were evaluated. The authors have used the MIC and MPC, as well as the pharmacokinetic-pharmacodynamic relationships in plasma and milk. MIC values were significantly different between drugs, unlike MPC values. Lower MIC values were obtained for danofloxacin and difloxacin, middle and higher values for enrofloxacin, ciprofloxacin and marbofloxacin. However, differences in MPC values were not found between drugs. At conventional doses, the AUC24/MIC and AUC24/MPC ratios were close to 30-80 hours and 5-30 hours, with exception of danofloxacin, in plasma and milk. The time inside the mutant selection window (TMSW) was close to 3-6 hours for enrofloxacin, ciprofloxacin and marbofloxacin, near to 8 hours for danofloxacin and 12-22 hours for difloxacin. From these data, the mutant selection window could be higher for danofloxacin and difloxacin compared with the other fluoroquinolones tested. The authors concluded that enrofloxacin and marbofloxacin, at conventional doses, could prevent the selection of bacterial subpopulations of S aureus, unlike danofloxacin and difloxacin, where higher doses could be used.
Choi, Nack-Shick; Song, Jae Jun; Chung, Dong-Min; Kim, Young Jae; Maeng, Pil Jae; Kim, Seung-Ho
A novel fibrinolytic enzyme (AJ) was purified from Staphylococcus sp. strain AJ screened from Korean salt-fermented Anchovy-jeot. Relative molecular weight of AJ was determined as 26 kDa by using SDS-PAGE and fibrin zymography. Based on a 2D gel, AJ was found to consist of three active isoforms (pI 5.5-6.0) with the same N-terminal amino acid sequence. AJ exhibited optimum pH and temperature at 2.5-3.0 and 85 degrees C, respectively. AJ kept 85% of the initial activity after heating at 100 degrees C for 20 min on the zymogram gel. The Michaelis constant (K (m)) and K (cat) values of AJ towards alpha-casein were 0.38 mM and 19.73 s(-1), respectively. AJ cleaved the A alpha-chain of fibrinogen but did not affect the B beta- and gamma-chains, indicating that it is an alpha-fibrinogenase. The fibrinolytic activity was inhibited by diisopropyl fluorophosphate, indicating AJ is a serine protease. Interestingly, AJ was very stable at acidic condition, SDS, and heat (100 degrees C), whereas it was easily degraded at neutral and alkaline conditions. In particular, AJ formed an active homo-dimer in the pH range from 7.0 to 8.0. To our knowledge, a similar combination of acid and heat stability has not yet been reported for other fibrinolytic enzymes.
Detection of antistaphylococcal and toxic compounds by biological assay systems developed with a reporter Staphylococcus aureus strain harboring a heat inducible promoter - lacZ transcriptional fusion.
Chanda, Palas Kumar; Ganguly, Tridib; Das, Malabika; Lee, Chia Yen; Luong, Thanh T; Sau, Subrata
Previously it was reported that promoter of groES-groEL operon of Staphylococcus aureus is induced by various cell-wall active antibiotics. In order to exploit the above promoter for identifying novel antistaphylococcal drugs, we have cloned the promoter containing region (P(g)) of groES-groEL operon of S. aureus Newman and found that the above promoter is induced by sublethal concentrations of many antibiotics including cell-wall active antibiotics. A reporter S. aureus RN4220 strain (designated SAU006) was constructed by inserting the P(g)-lacZ transcriptional fusion into its chromosome. Agarose-based assay developed with SAU006 shows that P(g) in single-copy is also induced distinctly by different classes of antibiotics. Data indicate that ciprofloxacin, rifampicin, ampicillin, and cephalothin are strong inducers, whereas, tetracycline, streptomycin and vancomycin induce the above promoter weakly. Sublethal concentrations of ciprofloxacin and ampicilin even have induced P(g) efficiently in microtiter plate grown SAU006. Additional studies show for the first time that above promoter is also induced weakly by arsenate salt and hydrogen peroxide. Taken together, we suggest that our simple and sensitive assay systems with SAU006 could be utilized for screening and detecting not only novel antistaphylococcal compounds but also different toxic chemicals.
Background A class of methicillin-resistant Staphylococcus aureus (MRSA) shows resistance to vancomycin only in the presence of ß-lactam antibiotics (BIVR). This type of vancomycin resistance is mainly attributable to the rapid depletion of free vancomycin in the presence of ß-lactam antibiotics. This means that ß-lactam antibiotics remain active or intact in BIVR culture, although most MRSA cells are assumed to produce ß-lactamase. We hypothesised that the BIVR cells either did not harbour the ß-lactamase gene, blaZ, or the gene was quiescent. We tested this hypothesis by determining ß-lactamase activity and conducting PCR amplification of blaZ. Results Five randomly selected laboratory stock BIVR strains showed an undetectable level of ß-lactamase activity and were blaZ-negative. Five non-BIVR stock strains showed an average ß-lactamase activity of 2.59 ± 0.35 U. To test freshly isolated MRSA, 353 clinical isolates were collected from 11 regionally distant hospitals. Among 25 BIVR strains, only 16% and 8% were blaZ positive and ß-lactamase-positive, respectively. In contrast, 95% and 61% of 328 non-BIVR strains had the blaZ gene and produced active ß-lactamase, respectively. To know the mechanism of low ß-lactamase activity in the BIVR cells, they were transformed with the plasmid carrying the blaZ gene. The transformants still showed a low level of ß-lactamase activity that was several orders of magnitude lower than that of blaZ-positive non-BIVR cells. Presence of the ß-lactamase gene in the transformants was tested by PCR amplification of blaZ using 11 pairs of primers covering the entire blaZ sequence. Yield of the PCR products was consistently low compared with that using blaZ-positive non-BIVR cells. Nucleotide sequencing of blaZ in one of the BIVR transformants revealed 10 amino acid substitutions. Thus, it is likely that the ß-lactamase gene was modified in the BIVR cells to downregulate active ß-lactamase production. Conclusions We
Gordon, Annika; Marshall, Jennelle; Ramdass, Kris; Stewart-Johnson, Alva; Adesiyun, Abiodun
Background Methicillin-resistant Staphylococcus aureus (MRSA) has emerged recently worldwide in production animals, particularly pigs and veal calves, which act as reservoirs for MRSA strains for human infection. The study determined the prevalence of MRSA and other resistant strains of S. aureus isolated from the anterior nares of pigs and human handlers on pig farms in Trinidad. Methods Isolation of S. aureus was done by concurrently inoculating Baird-Parker agar (BPA) and Chromagar MRSA (CHROM) with swab samples and isolates were identified using standard methods. Suspect MRSA isolates from Chromagar and BPA were subjected to confirmatory test using Oxoid PBP2 latex agglutination test. The disc diffusion method was used to determine resistance to antimicrobial agents. Results The frequency of isolation of MRSA was 2.1% (15 of 723) for pigs but 0.0% (0 of 72) for humans. Generally, for isolates of S. aureus from humans there was a high frequency of resistance compared with those from pigs, which had moderate resistance to the following antimicrobials: penicillin G (54.5%, 51.5%), ampicillin (59.1%, 49.5%), and streptomycin (59.1%, 37.1%), respectively. There was moderate resistance to tetracycline (36.4%, 41.2%) and gentamycin (27.2%, 23.7%) for human and pig S. aureus isolates, respectively, and low resistance to sulfamethoxazole-trimethoprim (4.5%, 6.2%) and norfloxacin (9.1%, 12.4%), respectively. The frequency of resistance to oxacillin by the disc method was 36.4 and 34.0% from S. aureus isolates from humans and pigs, respectively. Out of a total of 78 isolates of S. aureus from both human and pig sources that were resistant to oxacillin by the disc diffusion method, only 15 (19.2%) were confirmed as MRSA by the PBP'2 latex test kit. Conclusions The detection of MRSA strains in pigs, albeit at a low frequency, coupled with a high frequency of resistance to commonly used antimicrobial agents in pig and humans could have zoonotic and therapeutic implications
Kılıç, Abdullah; Doğan, Eyüp; Kaya, Sinem; Baysallar, Mehmet
Detection and identification of methicillin-resistant Staphylococcus aureus (MRSA) in clinical microbiology laboratories are important for the selection of appropriate treatment and obtaining epidemiological data. mecC gene, is a mecA homologue, showing almost 69% DNA similarity with the mecA gene and the encoded protein by this gene shows almost 63% similarity with the PBP2a/2' protein. Several studies indicated that mecC positive MRSA strains can be transmitted from the livestock to humans by cross contamination. Panton-Valentine leukocidin (PVL), a potent cytotoxin of S.aureus is also considered as an important virulence factor. The aim of this study was to determine the existence and prevalence of mecC and pvl genes among S.aureus strains isolated from clinical specimens. A total of 1700 S.aureus isolates including 1177 methicillin-susceptible S.aureus (MSSA) and 523 MRSA, isolated in our hospital between January 2007 to December 2014, were included in the study. The isolates were identified by both conventional methods and BD Phoenix automated system (BD Diagnostic Instrument Systems, USA). Antibiotic susceptibility testing was performed by Kirby-Bauer disk diffusion method with oxacillin (1 μg) and cefoxitin (30 μg) according to the CLSI standards. The presence of mecA gene was investigated by the use of real-time PCR, and the presence of pvl and mecC genes were detected by conventional PCR method. Among the patients, 44.6% (759/1700) were outpatients, 65.8% (1119/1700) were male and the mean age of of patients was 39.7 years. Of 1700 isolates evaluated in this study, 523 (30.7%) were positive for mecA gene, however all of them were negative for mecC gene. A total of 32 (1.8%) isolates were positive for pvl gene including 23 (1.9%) out of 1177 MSSA and nine (1.7%) out of 523 MRSA strains. Eighteen (56.2%) of the PVL-positive S.aureus strains were isolated from skin and soft tissue infections. The frequency of PVL detected in this study was similar to the
Paniagua-Contreras, Gloria; Monroy-Pérez, Eric; Gutiérrez-Lucas, Raúl; Sainz-Espuñes, Teresita; Bustos-Martínez, Jaime; Vaca, Sergio
Methicillin-resistant Staphylococcus aureus (MRSA) is the causal agent of multiple nosocomial infections worldwide, including catheter-associated bacteremia in hemodialysis patients. The purposes of this work were to genetically characterize a group of MRSA isolates from catheter-related infections of ambulatory Mexican hemodialysis patients and to determine whether the strains are the same as those carried by the patients in their anterior nares. Sixteen pairs of MRSA isolates from the catheter (cat) and anterior nares (N) of hemodialysis patients were compared using pulsed-field gel electrophoresis (PFGE), PCR detection of adhesion genes and other virulence markers, and an antibiogram. Three pairs of N/cat MRSA isolates (18.7 %) with identical resistograms also showed the same combination of PCR-detected markers and PFGE pattern; one additional pair showed only an identical electrophoretic PFGE pattern. Of the MRSA isolates, 75 % (n = 24) were resistant to ≥ 7 antibiotics, 4 isolates were resistant to 11 antibiotics, and 7 isolates were resistant to the 12 antibiotics tested. The most frequent virulence marker combination found was spa, clfA, clfB, cna, bbp, ebps, map/eap, sdrC, sdrD, sdrE, ica, agr (65.6 %, n = 21). The SCCmec alleles of the 32 MRSA isolates were IV (n = 20), I (n = 7), II (n = 4), and V (n = 1), and no SCCmec type III MRSA was found. The genotypic characterization of the MRSA isolates studied in this work will contribute to a better understanding of the virulence gene makeup of catheter-colonizing S. aureus strains and will help to lower the infection risk in these patients.
Tuchina, Elena S.; Petrov, Pavel O.; Ratto, Fulvio; Centi, Sonia; Pini, Roberto; Tuchin, Valery V.
The effect of NIR laser radiation (808 nm) on methicillin-sensitive and methicillin resistant strains of Staphylococcus aureus incubated with gold nanorods is studied. Nanorods having length of 44 (± 4) nm and diameter of 10 (± 3) nm with the absorption maximum in the NIR (800 nm), functionalized with human immunoglobulins IgA and IgG, were synthesized and used in the studies. The killing ability up to 97% of the microorganism populations by using this nanotechnology was shown.
Pepe, Olimpia; Blaiotta, Giuseppe; Moschetti, Giancarlo; Greco, Teresa; Villani, Francesco
Two types of white wheat bread (high- and low-type loaves) were investigated for rope spoilage. Thirty of the 56 breads tested developed rope spoilage within 5 days; the high-type loaves were affected by rope spoilage more than the low-type loaves. Sixty-one Bacillus strains were isolated from ropy breads and were characterized on the basis of their phenotypic and genotypic traits. All of the isolates were identified as Bacillus subtilis by biochemical tests, but molecular assays (randomly amplified polymorphic DNA PCR assay, denaturing gradient gel electrophoresis analysis, and sequencing of the V3 region of 16S ribosomal DNA) revealed greater Bacillus species variety in ropy breads. In fact, besides strains of B. subtilis, Bacillus licheniformis, Bacillus cereus, and isolates of Bacillus clausii and Bacillus firmus were also identified. All of the ropy Bacillus isolates exhibited amylase activity, whereas only 32.4% of these isolates were able to produce ropiness in bread slices after treatment at 96 degrees C for 10 min. Strains of lactic acid bacteria previously isolated from sourdough were first selected for antirope activity on bread slices and then used as starters for bread-making experiments. Prevention of growth of approximately 10(4) rope-producing B. subtilis G1 spores per cm(2) on bread slices for more than 15 days was observed when heat-treated cultures of Lactobacillus plantarum E5 and Leuconostoc mesenteroides A27 were added. Growth of B. subtilis G1 occurred after 7 days in breads started with Saccharomyces cerevisiae T22, L. plantarum E5, and L. mesenteroides A27.
Lavigne, Jean-Philippe; Audibert, Sylvain; Molinari, Nicolas; O'Callaghan, David; Keriel, Anne
It was recently observed that a glucose-enriched diet activates the insulin-like pathway in Caenorhabditis elegans, resulting in an inhibition of the FOXO transcription factor DAF-16. Because this signalling pathway is highly conserved from invertebrates to mammals and DAF-16 is a key player in innate immunity, we wondered whether a high-glucose diet, resembling the hyperglycaemic conditions in diabetic patients, would affect the susceptibility of C. elegans to bacterial pathogens isolated from different clinical situations (urinary tract or diabetic foot infections). We confirmed previous reports showing that such a diet decreases the lifespan of C. elegans fed with an avirulent Escherichia coli strain. However, glucose-fed nematodes appeared to be more resistant to most clinical isolates tested, showing that this invertebrate model does not mimic infections encountered in human diabetes, where patients show increased susceptibility to bacterial infections. This study also suggests that modulation of innate immunity in C. elegans, upon activation of the IGF1/insulin-like pathway by glucose, is not exclusively mediated by DAF-16, but also involves an additional factor that requires DAF-16 activity.
Haldar, Lopamudra; Gandhi, D. N.
Aim: To investigate the effect of oral administration of two Bacillus strains on fecal coliforms, Lactobacillus and Bacillus spp. in rat animal model. Materials and Methods: An in vivo experiment was conducted for 49-day period on 36 adult male albino Wister rats divided equally into to four groups. After 7-day adaptation period, one group (T1) was fed on sterile skim milk along with basal diet for the next 28 days. Second (T2) and (T3) groups received spore biomass of Bacillus coagulans B37 and Bacillus pumilus B9, respectively, suspended in sterilized skim milk at 8-9 log colony-forming units/ml plus basal diet for 28 days, while control group (T4) was supplied with clean water along with basal diet. There was a 14-day post-treatment period. A total of 288 fecal samples (8 fecal collections per rat) were collected at every 7-day interval starting from 0 to 49 days and subjected to the enumeration of the counts of coliforms and lactobacilli and Bacillus spores using respective agar media. In vitro acid and bile tolerance tests on both the strains were performed. Results: The rats those (T2 and T3) received either B. coagulans B37 or B. pumilus B9 spore along with non-fermented skim milk showed decrease (p<0.01) in fecal coliform counts and increase (p<0.05) in both fecal lactobacilli and Bacillus spore counts as compared to the control group (T4) and the group fed only skim milk (T1). In vitro study indicated that both the strains were found to survive at pH 2.0 and 3.0 even up to 3 h and tolerate bile up to 2.0% concentration even after 12 h of exposure. Conclusions: This study revealed that oral administration of either B. coagulans B37 or B. pumilus B9 strains might be useful in reducing coliform counts accompanied by concurrent increase in lactobacilli counts in the intestinal flora in rats. PMID:27536040
Yeung, M K
The nucleotide sequence of the Actinomyces viscosus T14V sialidase gene (nanH) and flanking regions was determined. An open reading frame of 2,703 nucleotides that encodes a predominately hydrophobic protein of 901 amino acids (M(r), 92,871) was identified. The amino acid sequence at the amino terminus of the predicted protein exhibited properties characteristic of a typical leader peptide. Five 12-amino-acid units that shared between 33 and 67% sequence identity were noted within the central domain of the protein. Each unit contained the sequence Ser-X-Asp-X-Gly-X-Thr-Trp, which is conserved among other bacterial and trypanosoma sp. sialidases. Thus, the A. viscosus T14V nanH gene and the other prokaryotic and eukaryotic sialidase genes evolved from a common ancestor. Southern hybridization analyses under conditions of high stringency revealed the existence of DNA sequences homologous to A. viscosus T14V nanH in the genomes of 18 strains of five Actinomyces species that expressed various levels of sialidase activity. The data demonstrate that the sialidase genes from divergent groups of Actinomyces spp. are highly conserved. Images PMID:8418033
Lindsay, Jodi A.
The staphylococci are Gram-positive cocci that divide to form clusters that look like grapes. By 16S ribosomal sequencing, they are most closely related to the Gram-positive, low G+C content Bacillus-Lactobacillus-Staphylococcus genera (Woese, 1987). There are over 30 species of staphylococci identified, and they are typically found on the skin and mucous membranes of mammals. About a dozen species are frequently carried on humans, including Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus capitis, Staphylococcus hominis, Staphylococcus cohnii, Staphylococcus lugdunensis, Staphylococcus schleiferi, Staphylococcus saprophyticus, Staphylococcus simulans, Staphylococcus warneri and Staphylococcus xylosus.
Huang, Ying; Benson, David R
Filamentous actinobacteria from the genus Frankia grow by hyphal tip extension and branching. The growth kinetics and branching pattern of Frankia are not well studied, especially at the early stages of mycelial development. Here, we compare the growth of Frankia sp. strain CcI3 in liquid cultures with and without proteose peptone #3 (PP3) using time-lapse photomicrography and image analysis. Individual hyphae showed a pseudolinear increase in length at early stages of development, whereas at the mycelial level, the aggregate length of hyphae described an exponential rate before slowing. Growth based on optical density or microscopic observations was similar in medium with or without PP3. However, PP3 altered the pattern of mycelial development by increasing branching. Distances between the hyphal apex and first branches were on average shorter in PP3-containing media. The final interbranch distances were also shorter in PP3 medium indicating that hyphae tended to branch earlier and more often when supplemented with PP3 to give a more compact mycelium. Vesicle development in nitrogen-fixing cultures limited cell expansion as a result of vesicles truncating growth on new branches. The results provide some explanation for the growth kinetics of Frankia and some indication of how growth rates may be improved.
Zhu, S; Schnell, S; Fischer, M
Cronobacter is associated with outbreaks of rare, but life-threatening cases of meningitis, necrotizing enterocolitis, and sepsis in newborns. This study was conducted to determine the effect of organic acids on growth of Cronobacter in laboratory medium and reconstituted powdered infant formula (PIF) as well as the bacteriostatic effect of slightly acidified infant formula when combined with neonatal gastric acidity. Inhibitory effect of seven organic acids on four acid sensitive Cronobacter strains was determined in laboratory medium with broth dilution method at pH 5.0, 5.5 and 6.0. Acetic, butyric and propionic acids were most inhibitive against Cronobacter in the laboratory medium. The killing effect of these three acids was partially buffered in reconstituted PIF. Under neonatal gastric acid condition of pH 5.0, the slightly acidified formula which did not exert inhibition effect solely reduced significantly the Cronobacter populations. A synergistic effect of formula moderately acidified with organic acid combined with the physiological infant gastric acid was visible in preventing the rapid growth of Cronobacter in neonatal stomach. The study contributed to a better understanding of the inhibitory effect of organic acids on Cronobacter growth in different matrixes and provided new ideas in terms of controlling bacteria colonization and translocation by acidified formula.
Aydeniz Ozansoy, Fatma; Cevahir, Nural; Kaleli, İlknur
Staphylococcus aureus is one of the most common cause of both community and healthcare-associated infections. As staphylococci have developed resistance to various antibiotics, initially to penicillins then to methicillin and glycopeptides and have the ability to cause epidemics, they continue to be a major problem from past to present. Methicillin resistance gave rise to the use of alternative antibiotics such as macrolides, however worldwide development of macrolide resistance limited the use of these antibiotics. Macrolide resistance occurs either through target site modification (MLS(B) phenotype, encoded by erm genes), efflux pumps (MS phenotype, encoded by msrA/B genes) or decreased cell wall permeability. The aim of this study was to investigate the MLS(B) resistance of clinical S.aureus strains with phenotypic and genotypic methods. A total of 404 S.aureus strains isolated from different clinical samples (50% wound, 15% tracheal aspirate and 35% other samples) of inpatients (93.3%) and outpatients (6.7%) were included in the study. Double disc synergy test (D-test) was used for the phenotypical research and PCR was used for the genotypical research of MLS(B) resistance of isolates. One hundred fifty eight (39.1%) of the S.aureus isolates were methicillin-resistant (MRSA), and 246 (60.9%) were methicillin-susceptible (MSSA). By the use of D-test, constitutive (cMLS(B)) and inducible (iMLS(B)) clindamycin resistance were detected in 19 and 111 isolates, respectively, while five isolates were MS phenotype and 268 isolates were S phenotype (susceptible to erythromycin and clindamycin). The resistance genes of 136 isolates with MLS(B) resistance phenotype were determined genotypically and among 111 isolates showing iMLS(B) phenotype ermA gene was found in 81.9% (83 MRSA, 8 MSSA), ermC gene in 10.8% (7 MRSA, 5 MSSA), msrA gene in 10.8% (11 MRSA, 1 MSSA), msrB gene in 1.8% (2 MRSA) and ermB gene in 0.9% (1 MRSA). Among 19 strains with cMLS(B) phenotype, ermA was
Foodborne illness outbreaks occasionally occur as a result of microbiologically contaminated crustaceans, including shrimp. Foodborne pathogens occasionally found on shrimp include Listeria monocytogenes, Salmonella spp., Staphylococcus aureus, and Vibrios. In this study the microbiological qualit...
Antimicrobial activity of biogenically produced spherical Se-nanomaterials embedded in organic material against Pseudomonas aeruginosa and Staphylococcus aureus strains on hydroxyapatite-coated surfaces.
Piacenza, Elena; Presentato, Alessandro; Zonaro, Emanuele; Lemire, Joseph A; Demeter, Marc; Vallini, Giovanni; Turner, Raymond J; Lampis, Silvia
In an effort to prevent the formation of pathogenic biofilms on hydroxyapatite (HA)-based clinical devices and surfaces, we present a study evaluating the antimicrobial efficacy of Spherical biogenic Se-Nanostructures Embedded in Organic material (Bio Se-NEMO-S) produced by Bacillus mycoides SelTE01 in comparison with two different chemical selenium nanoparticle (SeNP) classes. These nanomaterials have been studied as potential antimicrobials for eradication of established HA-grown biofilms, for preventing biofilm formation on HA-coated surfaces and for inhibition of planktonic cell growth of Pseudomonas aeruginosa NCTC 12934 and Staphylococcus aureus ATCC 25923. Bio Se-NEMO resulted more efficacious than those chemically produced in all tested scenarios. Bio Se-NEMO produced by B. mycoides SelTE01 after 6 or 24 h of Na2 SeO3 exposure show the same effective antibiofilm activity towards both P. aeruginosa and S. aureus strains at 0.078 mg ml(-1) (Bio Se-NEMO6 ) and 0.3125 mg ml(-1) (Bio Se-NEMO24 ). Meanwhile, chemically synthesized SeNPs at the highest tested concentration (2.5 mg ml(-1) ) have moderate antimicrobial activity. The confocal laser scanning micrographs demonstrate that the majority of the P. aeruginosa and S. aureus cells exposed to biogenic SeNPs within the biofilm are killed or eradicated. Bio Se-NEMO therefore displayed good antimicrobial activity towards HA-grown biofilms and planktonic cells, becoming possible candidates as new antimicrobials.
Cadieux, Brigitte; Vijayakumaran, Vithooshan; Bernards, Mark A; McGavin, Martin J; Heinrichs, David E
Part of the human host innate immune response involves the secretion of bactericidal lipids on the skin and delivery of triglycerides into abscesses to control invading pathogens. Two Staphylococcus aureus lipases, named SAL1 and SAL2, were identified in the community-associated methicillin-resistant S. aureus strain USA300, which, presumably, are produced and function to degrade triglycerides to release free fatty acids. We show that the SAL2 lipase is one of the most abundant proteins secreted by USA300 and is proteolytically processed from the 72-kDa proSAL2 to the 44-kDa mature SAL2 by the metalloprotease aureolysin. We show that spent culture supernatants had lipase activity on both short- and long-chain fatty acid substrates and that deletion of gehB, encoding SAL2, resulted in the complete loss of these activities. With the use of gas chromatography-mass spectrometry, we show that SAL2 hydrolyzed trilinolein to linoleic acid, a fatty acid with known antistaphylococcal properties. When added to cultures of USA300, trilinolein and, to a lesser extent, triolein inhibited growth in a SAL2-dependent manner. This effect was shown to be due to the enzymatic activity of SAL2 on these triglycerides, since the catalytically inactive SAL2 Ser412Ala mutant was incapable of hydrolyzing the triglycerides or yielding delayed growth in their presence. Overall, these results reveal that SAL2 hydrolyzes triglycerides of both short- and long-chain fatty acids and that the released free fatty acids have the potential to cause significant delays in growth, depending on the chemical nature of the free fatty acid.
Liu, Xiaoli; Liang, Jiansheng; Jiang, Yuanshan; Wang, Bin; Yuan, Hong; Zhang, Lihua; Zhou, Yanfei; Xu, Huiqiong; Zhou, Wang
This study aims to investigate the antimicrobial susceptibility, molecular characteristics and virulence genes of community-acquired methicillin-resistant ITALIC! Staphylococcus aureus(CA-MRSA) isolates with skin and soft tissue infections (SSTIs). Outpatients with SSTIs visiting five medical and health institutions were enrolled from 2011 to 2013. Available ITALIC! S. aureus isolates were characterized by antimicrobial susceptibility testing, and detection of PVL genes. For CA-MRSA isolates, we performed typing of staphylococcal cassette chromosome ITALIC! mec(SCC ITALIC! mec), multi locus sequence typing (MLST) and carriage of 27 virulence genes. A total of 203 ITALIC! S. aureusstrains were isolated from 1400 outpatients with SSTIs, and 21 (10.3%) were CA-MRSA isolates. The positive rate of PVL genes among ITALIC! S. aureus, CA-MRSA and methicillin-susceptible ITALIC! S. aureus(MSSA) isolates were 39.4%, 71.4% and 35.7%, respectively. CA-MRSA strains had greater sensitivity to non-β-lactam antimicrobial agents. All CA-MRSA isolates belonged to SCC ITALIC! mecIV and V, accounting for 47.6% and 52.4%, respectively. ST59 was the most common lineage accounting for 76.2%; ST59-SCC ITALIC! mecIVa-PVL-positive clone was found to be the predominant clone, accounting for 38.1%. All CA-MRSA isolates were found to be positive for one or more virulence genes, 28.6% of isolates carried PVL, ITALIC! seb, ITALIC! sek, ITALIC! seq, ITALIC! hla, ITALIC! hlb, ITALIC! hldand ITALIC! hlg-2. CA-MRSA infections were relatively uncommon in outpatients with SSTIs, but they carried many virulence genes, ST59-SCC ITALIC! mecIV a-PVL-positive clone was the predominant clone in Wuhan, China.
Sander, Gunnar; Börner, Tina; Kriegeskorte, André; von Eiff, Christof; Becker, Karsten; Mahabir, Esther
Coagulase-negative staphylococci (CoNS) form a thick, multilayered biofilm on foreign bodies and are a major cause of nosocomial implant-associated infections. Although foreign body infection models are well-established, limited in vivo data are available for CoNS with small-colony-variant (SCV) phenotype described as causative agents in implant-associated infections. Therefore, we investigated the impact of the Staphylococcus epidermidis phenotype on colonization of implanted PVC catheters and abscess formation in three different mouse strains. Following introduction of a catheter subcutaneously in each flank of 8- to 12-week-old inbred C57BL/6JCrl (B6J), outbred Crl:CD1(ICR) (CD-1), and inbred BALB/cAnNCrl (BALB/c) male mice, doses of S. epidermidis O-47 wild type, its hemB mutant with stable SCV phenotype, or its complemented mutant at concentrations of 10(6) to 10(9) colony forming units (CFUs) were gently spread onto each catheter. On day 7, mice were sacrificed and the size of the abscesses as well as bacterial colonization was determined. A total of 11,500 CFUs of the complemented mutant adhered to the catheter in BALB/c followed by 9,960 CFUs and 9,900 CFUs from S. epidermidis wild type in BALB/c and CD-1, respectively. SCV colonization was highest in CD-1 with 9,500 CFUs, whereas SCVs were not detected in B6J. The minimum dose that led to colonization or abscess formation in all mouse strains was 10(7) or 10(8) CFUs of the normal phenotype, respectively. A minimum dose of 10(8) or 10(9) CFU of the hemB mutant with stable SCV phenotype led to colonization only or abscess formation, respectively. The largest abscesses were detected in BALB/c inoculated with wild type bacteria or SCV (64 mm(2) vs. 28 mm(2)). Our results indicate that colonization and abscess formation by different phenotypes of S. epidermidis in a foreign body infection model is most effective in inbred BALB/c followed by outbred CD-1 and inbred B6J mice.
Dziva, Francis; Wint, Crystal; Auguste, Tennille; Heeraman, Carolyn; Dacon, Cherrelle; Yu, Priscilla; Koma, Lee M.
Background Otitis externa is a common inflammatory ear disease in dogs caused by a variety of pathogens, and coagulase-positive staphylococci are frequently isolated from such infections. Objective To identify antimicrobial susceptibility profiles and methicillin-resistant strains among coagulase-positive staphylococci isolated from otitis externa in dogs. Methods A cross-sectional study was performed over 2 years on 114 client-owned dogs presented to the Veterinary Teaching Hospital with a primary complaint of ear infections. Swabs were obtained from both ears and cultured for staphylococci which were subsequently confirmed as coagulase-positive using rabbit plasma. Antimicrobial susceptibility assays were assessed on all isolates followed by subsequent genetic analysis for species identification and detection of the mecA gene. Results Sixty-five coagulase-positive staphylococci were isolated from 114 client-owned dogs. The isolates exhibited resistance against neomycin (58.5%), streptomycin (49.2%), penicillin (49.2%), polymyxin B (44.6%), tetracycline (36.9%), sulphamethoxazole/trimethoprim (33.8%), kanamycin (33.8%), doxycycline (32.3%), norfloxacin (23.1%), amoxicillin/clavulanate (20%), ciprofloxacin (20%), enrofloxacin (18.5%), gentamicin (16.9%), and cephalothin (9.2%). Forty (61.5%) of the isolates were resistant to at least three or more antimicrobials and 10 were sensitive to all. Using a multiplex polymerase chain reaction assay based on species-specific regions of the thermonuclease (nuc) gene, 38/65 (58.5%) isolates were classified as Staphylococcus aureus, 23/65 (35.4%) as S. pseudintermedius, 2/65 (3.1%) as S. intermedius, and 2/65 (3.1%) as S. schleiferi. Analysis for the mecA gene revealed two positive isolates of S. pseudintermedius which were oxacillin-resistant, representing a first report of such organisms in the Caribbean. Conclusion Despite the relatively high prevalence of multidrug-resistant coagulase-positive staphylococci in Trinidad
Saranya, Raju; Aarthi, Raju; Sankaran, Krishnan
Spread of drug-resistant Staphylococcus spp. into communities pose danger demanding effective non-invasive and non-destructive tools for its early detection and surveillance. Characteristic volatile organic compounds (VOCs) produced by bacteria offer new diagnostic targets and novel approaches not exploited so far in infectious disease diagnostics. Our search for such characteristic VOC for Staphylococcus spp. led to the depiction of 2-[3-acetoxy-4,4,14-trimethylandrost-8-en-17-yl] propanoic acid (ATMAP), a moderately volatile compound detected both in the culture and headspace when the organism was grown in tryptone soya broth (TSB) medium. A simple and inexpensive colorimetric method (colour change from yellow to orange) using methyl red as the pH indicator provided an absolutely specific way for identifying Staphylococcus spp., The assay performed in liquid cultures (7-h growth in TSB) as well as in the headspace of plate cultures (grown for 10 h on TSA) was optimised in a 96-well plate and 12-well plate formats, respectively, employing a set of positive and negative strains. Only Staphylococcus spp. showed the distinct colour change from yellow to orange due to the production of the above VOC while in the case of other organisms, the reagent remained yellow. The method validated using known clinical and environmental strains (56 including Staphylococcus, Proteus, Pseudomonas, Klebsiella, Bacillus, Shigella and Escherichia coli) was found to be highly efficient showing 100% specificity and sensitivity. Such simple methods of bacterial pathogen identification are expected to form the next generation tools for the control of infectious diseases through early detection and surveillance of causative agents.
[Spreading and mechanisms of antibiotic resistance of microorganisms, producing beta-lactamases. Molecular mechanisms of resistance to beta-lactams of Klebsiella spp. strains, isolated in cases of nosocomial infections].
Ivanov, D V; Egorov, A M
Antibiotic sensivity of nosocomial Klebsiella spp. strains (n = 212), isolated from patients treated in 30 medical centers of 15 various regions of Russia was investigated. The Klebsiella genus was represented by the following species: Klebsiella pneumoniae ss. pneumoniae--182 (85.8%), Klebsiella pneumoniae ss. ozaenae--1 (0.5%), Klebsiella oxytoca--29 (13.7%) isolates. The most active antibacterial agents against the investigated strains were carbapenems (imipenem and meropenem). Among 3rd generation cephalosporine the lowest MICs were observed for ceftazidime/clavulanic acid (MIC50--0.25 microg/ml, MIC90--64 microg/ml) and cefoperazone/sulbactam (MIC50--16 microg/ml, MIC90--64 microg/ml). Beta-lactamase genes (TEM, SHV, CTX) were detected in 42 Klebsiella pneumoniae ss. pneumoniae strains by PCR. Alone or in various combinations TEM type beta-lactamases have been found in 16 (38.1%) isolates, SHV--in 29 (69%), and CTX--in 27 (64.3%). Combinations of 2 different determinants were detected in 23.8% of the isolates, 3--in 26.2%. There were not isolates producing MBL class B among resistant to carbapenems nosocomial Klebsiella spp. strains.
Adegoke, G O
Of 136 strains of coagulase-negative staphylococci isolated from healthy and sick human beings, goats, sheep, antelope and other animals, 88 (64.7%) were Staphylococcus sciuri and 35 (25.7%) were S. lentus and the remainder Staphylococcus gallinarum. The strains of S. sciuri were isolated from humans with boils and wounds, goats with pestes des petits ruminants (PPR) and dogs with nasal discharge. One isolate of S. gallinarum came from a fowl with chronic respiratory disease and 11 others were isolated from goats. The characteristics of S. sciuri, S. lentus and S. gallinarum isolated from different sources were similar.
Hughes, Grant L.; Raygoza Garay, Juan Antonio; Koundal, Vikas; Mwangi, Michael M.
Staphylococcus hominis is a culturable component of the bacterial microbiome of Anopheles stephensi. Here, we present the annotated draft genome sequences of three S. hominis isolates from A. stephensi. These genomic resources will facilitate experiments to further our understanding of the role of bacteria in mosquito biology. PMID:26966197
Johnson, Ryan C.; Crawford, Katrina; Lanier, Jeffrey B.; Merrell, D. Scott
We describe a cutaneous abscess caused by catalase-negative methicillin-susceptible Staphylococcus aureus subsp. aureus in a patient who was concomitantly colonized with virulent USA300 methicillin-resistant S. aureus (MRSA). Sequencing of the katA gene demonstrated a thymine insertion leading to a frameshift mutation and premature truncation of catalase to 21 amino acids. PMID:24131694
Levin-Edens, Emily; Meschke, John Scott; Roberts, Marilyn C.
Recreational beach environments have been recently identified as a potential reservoir for methicillin-resistant Staphylococcus aureus (MRSA); however, accurate quantification methods are needed for the development of risk assessments. This novel most-probable-number approach for MRSA quantification offers improved sensitivity and specificity by combining broth enrichment with MRSA-specific chromogenic agar. PMID:21441335
Full-Genome Sequencing Identifies in the Genetic Background Several Determinants That Modulate the Resistance Phenotype in Methicillin-Resistant Staphylococcus aureus Strains Carrying the Novel mecC Gene.
Milheiriço, Catarina; de Lencastre, Hermínia; Tomasz, Alexander
Most methicillin-resistant Staphylococcus aureus (MRSA) strains are resistant to beta-lactam antibiotics due to the presence of the mecA gene, encoding an extra penicillin-binding protein (PBP2A) that has low affinity for virtually all beta-lactam antibiotics. Recently, a new resistance determinant-the mecC gene-was identified in S. aureus isolates recovered from humans and dairy cattle. Although having typically low MICs to beta-lactam antibiotics, MRSA strains with the mecC determinant are also capable of expressing high levels of oxacillin resistance when in an optimal genetic background. In order to test the impact of extensive beta-lactam selection on the emergence of mecC-carrying strains with high levels of antibiotic resistance, we exposed the prototype mecC-carrying MRSA strain, LGA251, to increasing concentrations of oxacillin. LGA251 was able to rapidly adapt to high concentrations of oxacillin in growth medium. In such laboratory mutants with increased levels of oxacillin resistance, we identified mutations in genes with no relationship to the mecC regulatory system, indicating that the genetic background plays an important role in the establishment of the levels of oxacillin resistance. Our data also indicate that the stringent stress response plays a critical role in the beta-lactam antibiotic resistance phenotype of MRSA strains carrying the mecC determinant.
Sarkisian, S A; Janssen, M J; Matta, H; Henry, G E; Laplante, K L; Rowley, D C
Biofilm embedded bacterial pathogens such as Staphylococcus spp., Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii are difficult to eradicate and are major sources of bacterial infections. New drugs are needed to combat these pathogens. Hypericum is a plant genus that contains species known to have antimicrobial properties. However, the specific constituents responsible for the antimicrobial properties are not entirely known, nor have most compounds been tested as inhibitors of biofilm development. The investigation presented here tested seven secondary metabolites isolated from the species Hypericum densiflorum, Hypericum ellipticum, Hypericum prolificum, and Hypericum punctatum as inhibitors of bacterial growth and biofilm production. Assays were conducted against Staphylococcus epidermidis, Staphylococcus aureus, clinical methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii. Five of the seven compounds demonstrated growth inhibition against the Gram-positive bacteria with minimum inhibitory concentrations (MIC) ranging from 1.95 µg/mL to 7.81 µg/mL. Four of the secondary metabolites inhibited biofilm production by certain Gram-positive strains at sub-MIC concentrations.
Implementation of a novel in vitro model of infection of reconstituted human epithelium for expression of virulence genes in methicillin-resistant Staphylococcus aureus strains isolated from catheter-related infections in Mexico
Background Methicillin-resistant Staphylococcus aureus (MRSA) are clinically relevant pathogens that cause severe catheter-related nosocomial infections driven by several virulence factors. Methods We implemented a novel model of infection in vitro of reconstituted human epithelium (RHE) to analyze the expression patterns of virulence genes in 21 MRSA strains isolated from catheter-related infections in Mexican patients undergoing haemodialysis. We also determined the phenotypic and genotypic co-occurrence of antibiotic- and disinfectant-resistance traits in the S. aureus strains, which were also analysed by pulsed-field-gel electrophoresis (PFGE). Results In this study, MRSA strains isolated from haemodialysis catheter-related infections expressed virulence markers that mediate adhesion to, and invasion of, RHE. The most frequent pattern of expression (present in 47.6% of the strains) was as follows: fnbA, fnbB, spa, clfA, clfB, cna, bbp, ebps, eap, sdrC, sdrD, sdrE, efb, icaA, and agr. Seventy-one percent of the strains harboured the antibiotic- and disinfectant-resistance genes ermA, ermB, tet(M), tet(K), blaZ, qacA, qacB, and qacC. PFGE of the isolated MRSA revealed three identical strains and two pairs of identical strains. The strains with identical PFGE patterns showed the same phenotypes and genotypes, including the same spa type (t895), suggesting hospital personnel manipulating the haemodialysis equipment could be the source of catheter contamination. Conclusion These findings help define the prevalence of MRSA virulence factors in catheter-related infections. Some of the products of the expressed genes that we detected in this work may serve as potential antigens for inclusion in a vaccine for the prevention of MRSA-catheter-related infections. PMID:24405688
Comparison of procedures for the extraction of supernatants and cytotoxicity tests in Vero cells, applied to assess the toxigenic potential of Bacillus spp. and Lactobacillus spp., intended for use as probiotic strains.
Blanch, Anicet R; Méndez, Javier; Castel, Susana; Reina, Manuel
Interest in using Bacillus strains as probiotic components of animal feeds has grown in recent years. However, some of these strains, especially those taxonomically related to the Bacillus cereus group, may have enterotoxigenic activity. Assessment of their toxigenic potential by well-established and robust protocols is required before authorizing their use in animal nutrition. Three methods of extraction and concentration of supernatants of Bacillus and Lactobacillus strains (methanol extraction, ammonium sulphate and ultrafiltration concentration) and three cytotoxic tests in Vero cells (WST-1, LDH and protein synthesis inhibition assays) for the assessment of the cytotoxicity activity of Lactobacillus strains (as probiotic strains in human and animal nutrition) and Bacillus toyonensis BCT-7112(T) (as animal probiotic strain in animal nutrition-Toyocerin®-) were evaluated in this study. Methanol extraction was not useful under any circumstances. The other two concentration methods (ammonium sulphate and ultrafiltration) were feasible, with slightly greater sensitivity achieved by ultrafiltration. The probiotic strain B. toyonensis BCT-7112(T) proved to be a non-cytotoxic strain in all the protocols tested. However, some Lactobacillus strains showed cytotoxicity activity, regardless of the protocols applied.
Olson, Michael E.; Horswill, Alexander R.
The genetic manipulation of Staphylococcus epidermidis for molecular experimentation has long been an area of difficulty. Many of the traditional laboratory techniques for strain construction are laborious and hampered by poor efficiency. The ability to move chromosomal genetic markers and plasmids using bacteriophage transduction has greatly increased the speed and ease of S. epidermidis studies. These molecular genetic advances have advanced the S. epidermidis research field beyond a select few genetically tractable strains and facilitated investigations of clinically relevant isolates. PMID:24222465
Mahrouki, Sihem; Chihi, Hela; Bourouis, Amel; Ayari, Khaoula; Ferjani, Mustapha; Moussa, Mohamed Ben; Belhadj, Omrane
The aim of this study is to report the emergence of IncA/C conjugative plasmids harboring blaTEM-24, blaDHA-1, qnrA6, and aac(6')-Ib-cr genes among Providencia spp. isolates recovered in 2008 in Tunisia. The double-disk synergy test confirmed the phenotype extended-spectrum β-lactamase (ESBL) in 2 Providencia stuartii and 5 Providencia rettgeri. These ESBLs were coresistant to cefoxitin, chloramphenicol, ofloxacin, and sulfonamides but remained susceptible to imipenem. Three β-lactamases TEM-2, TEM-24, and DHA-1 were detected. blaTEM-24, blaDHA-1, aac(6')-Ib-cr, and qnrA6 genes were successfully transferred to Escherichia coli strain HB101, and they were found located on the conjugatifs IncA/C plasmids. Genetic relatedness showed similar and different patterns among P. stuartii and P. rettgeri strains, respectively.
Estrada, Cecilia S M Lucero; Alcaráz, Lucia E; Satorres, Sara E; Manfredi, Eduardo; Velázquez, Lidia Del C
An increase in the consumption of fruit juices and minimally processed fruits salads has been observed in recent years all over the world. In this work, the microbiological quality of artisan fruit salads was analysed. Faecal coliforms, Salmonella spp, Shigella spp, Yersinia enterocolitica and Escherichia coli O157:H7 were not detected; nevertheless, eleven strains of Staphylococcus aureus were isolated. By multiplex PCR, all isolates showed positive results for S. aureus 16S rRNA gene and 63.6% of them were positive for sea gene. Furthermore, PCR sea positive strains were able to produce the corresponding enterotoxin. Finally, the inactivation of these strains in fruit salads by nisin, lysozyme and EDTA, was studied. EDTA produced a total S. aureus growth inhibition after 60 h of incubation at a concentration of 250 mg/L. The presence of S. aureus might indicate inadequate hygiene conditions during salad elaboration; however, the enterotoxigenicity of the strains isolated in this study, highlights the risk of consumers' intoxication. EDTA could be used to inhibit the growth of S. aureus in artisan fruit salads and extend the shelf life of these products.
Estrada, Cecilia S.M. Lucero; Alcaráz, Lucia E.; Satorres, Sara E.; Manfredi, Eduardo; Velázquez, Lidia del C.
An increase in the consumption of fruit juices and minimally processed fruits salads has been observed in recent years all over the world. In this work, the microbiological quality of artisan fruit salads was analysed. Faecal coliforms, Salmonella spp, Shigella spp, Yersinia enterocolitica and Escherichia coli O157:H7 were not detected; nevertheless, eleven strains of Staphylococcus aureus were isolated. By multiplex PCR, all isolates showed positive results for S. aureus 16S rRNA gene and 63.6% of them were positive for sea gene. Furthermore, PCR sea positive strains were able to produce the corresponding enterotoxin. Finally, the inactivation of these strains in fruit salads by nisin, lysozyme and EDTA, was studied. EDTA produced a total S. aureus growth inhibition after 60 h of incubation at a concentration of 250 mg/L. The presence of S. aureus might indicate inadequate hygiene conditions during salad elaboration; however, the enterotoxigenicity of the strains isolated in this study, highlights the risk of consumers’ intoxication. EDTA could be used to inhibit the growth of S. aureus in artisan fruit salads and extend the shelf life of these products. PMID:24688505
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.
Multiple-locus variable-number tandem repeat fingerprinting as a method for rapid and cost-effective typing of animal-associated Staphylococcus aureus strains from lineages other than sequence type 398.
Kosecka-Strojek, Maja; Ilczyszyn, Weronika M; Buda, Aneta; Polakowska, Klaudia; Murzyn, Krzysztof; Panz, Tomasz; Bialecka, Anna; Kasprowicz, Andrzej; Jakubczak, Antoni; Krol, Jaroslaw; Wieliczko, Alina; Wladyka, Benedykt; Miedzobrodzki, Jacek
In veterinary medicine, Staphylococcus aureus is associated with a range of mild to severe infections. The high density of livestock in intensive farming systems increases the risk of disease spread and hampers its control and measures of prevention, making S. aureus one of the most important animal pathogens. Multiple-locus variable-number tandem repeat fingerprinting (MLVF) has been successfully applied to the characterization of livestock-associated meticillin-resistant Staphylococcus aureus (MRSA) ST398 but not to the characterization of a wide range of other animal isolates. The objective of the current study was to examine the effectiveness of MLVF for studying S. aureus strains isolated from households, farms and exotic animals in three regions of Poland. MLVF, random amplification of polymorphic DNA (RAPD), spa typing and diagnostic microarrays were compared to determine the most suitable combination of methods for veterinary purposes. MLVF generated results consistent with host and geographic origins, reflecting population structures with a high concordance to spa typing results. MLVF has been proven to be a rapid, highly discriminatory and cost-effective method suitable for molecular typing in veterinary settings.
Jawad, A; Heritage, J; Snelling, A M; Gascoyne-Binzi, D M; Hawkey, P M
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
Pardo, Lorena; Machado, Virginia; Mollerach, Marta; Mota, María Inés; Tuchscherr, Lorena P. N.; Gadea, Pilar; Gardella, Noella; Sordelli, Daniel O.; Vola, Magdalena; Schelotto, Felipe; Varela, Gustavo
We analyzed 90 nonduplicates community-associated methicillin-resistant S. aureus (CA-MRSA) strains isolated from skin and soft-tissue infections. All strains were mecA positive. Twenty-four of the 90 strains showed inducible macrolide-lincosamide-streptogramin B resistance. All strains produced α-toxin; 96% and 100% of them displayed positive results for lukS-F and cna genes, respectively. Eigthy-five strains expressed capsular polysaccharide serotype 8. Six different pulsotypes were discriminated by pulsed-field gel electrophoresis (PFGE) and three predominant groups of CA-MRSA strains (1, 2, and 4) were identified, in agreement with phenotypic and genotypic characteristics. Strains of group 1 (pulsotype A, CP8+, and Panton-Valentine leukocidin (PVL)+) were the most frequently recovered and exhibited a PFGE band pattern identical to other CA-MRSA strains previously isolated in Uruguay and Brazil. Three years after the first local CA-MRSA report, these strains are still producing skin and soft-tissue infections demonstrating the stability over time of this community-associated emerging pathogen. PMID:20016669
Lack of Involvement of Fenton Chemistry in Death of Methicillin-Resistant and Methicillin-Sensitive Strains of Staphylococcus aureus and Destruction of Their Genomes on Wet or Dry Copper Alloy Surfaces
The pandemic of hospital-acquired infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has declined, but the evolution of strains with enhanced virulence and toxins and the increase of community-associated infections are still a threat. In previous studies, 107 MRSA bacteria applied as simulated droplet contamination were killed on copper and brass surfaces within 90 min. However, contamination of surfaces is often via finger tips and dries rapidly, and it may be overlooked by cleaning regimes (unlike visible droplets). In this new study, a 5-log reduction of a hardy epidemic strain of MRSA (epidemic methicillin-resistant S. aureus 16 [EMRSA-16]) was observed following 10 min of contact with copper, and a 4-log reduction was observed on copper nickel and cartridge brass alloys in 15 min. A methicillin-sensitive S. aureus (MSSA) strain from an osteomyelitis patient was killed on copper surfaces in 15 min, and 4-log and 3-log reductions occurred within 20 min of contact with copper nickel and cartridge brass, respectively. Bacterial respiration was compromised on copper surfaces, and superoxide was generated as part of the killing mechanism. In addition, destruction of genomic DNA occurs on copper and brass surfaces, allaying concerns about horizontal gene transfer and copper resistance. Incorporation of copper alloy biocidal surfaces may help to reduce the spread of this dangerous pathogen. PMID:26826226
Molecular Types of Methicillin-Resistant Staphylococcus aureus and Methicillin-Sensitive S. aureus Strains Causing Skin and Soft Tissue Infections and Nasal Colonization, Identified in Community Health Centers in New York City
Pardos de la Gandara, Maria; Raygoza Garay, Juan Antonio; Mwangi, Michael; Tobin, Jonathan N.; Tsang, Amanda; Khalida, Chamanara; D'Orazio, Brianna; Kost, Rhonda G.; Leinberger-Jabari, Andrea; Coffran, Cameron; Evering, Teresa H.; Coller, Barry S.; Balachandra, Shirish; Urban, Tracie; Parola, Claude; Salvato, Scott; Jenks, Nancy; Wu, Daren; Burgess, Rhonda; Chung, Marilyn; de Lencastre, Herminia
In November 2011, The Rockefeller University Center for Clinical and Translational Science (CCTS), the Laboratory of Microbiology and Infectious Diseases, and Clinical Directors Network (CDN) launched a research and learning collaborative project with six community health centers in the New York City metropolitan area to determine the nature (clonal type) of community-acquired Staphylococcus aureus strains causing skin and soft tissue infections (SSTIs). Between November 2011 and March 2013, wound and nasal samples from 129 patients with active SSTIs suspicious for S. aureus were collected and characterized by molecular typing techniques. In 63 of 129 patients, the skin wounds were infected by S. aureus: methicillin-resistant S. aureus (MRSA) was recovered from 39 wounds and methicillin-sensitive S. aureus (MSSA) was recovered from 24. Most—46 of the 63–wound isolates belonged to the CC8/Panton-Valentine leukocidin-positive (PVL+) group of S. aureus clone USA300: 34 of these strains were MRSA and 12 were MSSA. Of the 63 patients with S. aureus infections, 30 were also colonized by S. aureus in the nares: 16 of the colonizing isolates were MRSA, and 14 were MSSA, and the majority of the colonizing isolates belonged to the USA300 clonal group. In most cases (70%), the colonizing isolate belonged to the same clonal type as the strain involved with the infection. In three of the patients, the identity of invasive and colonizing MRSA isolates was further documented by whole-genome sequencing. PMID:26063853
Lack of Involvement of Fenton Chemistry in Death of Methicillin-Resistant and Methicillin-Sensitive Strains of Staphylococcus aureus and Destruction of Their Genomes on Wet or Dry Copper Alloy Surfaces.
Warnes, Sarah L; Keevil, C William
The pandemic of hospital-acquired infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has declined, but the evolution of strains with enhanced virulence and toxins and the increase of community-associated infections are still a threat. In previous studies, 10(7) MRSA bacteria applied as simulated droplet contamination were killed on copper and brass surfaces within 90 min. However, contamination of surfaces is often via finger tips and dries rapidly, and it may be overlooked by cleaning regimes (unlike visible droplets). In this new study, a 5-log reduction of a hardy epidemic strain of MRSA (epidemic methicillin-resistant S. aureus 16 [EMRSA-16]) was observed following 10 min of contact with copper, and a 4-log reduction was observed on copper nickel and cartridge brass alloys in 15 min. A methicillin-sensitive S. aureus (MSSA) strain from an osteomyelitis patient was killed on copper surfaces in 15 min, and 4-log and 3-log reductions occurred within 20 min of contact with copper nickel and cartridge brass, respectively. Bacterial respiration was compromised on copper surfaces, and superoxide was generated as part of the killing mechanism. In addition, destruction of genomic DNA occurs on copper and brass surfaces, allaying concerns about horizontal gene transfer and copper resistance. Incorporation of copper alloy biocidal surfaces may help to reduce the spread of this dangerous pathogen.
Molecular Types of Methicillin-Resistant Staphylococcus aureus and Methicillin-Sensitive S. aureus Strains Causing Skin and Soft Tissue Infections and Nasal Colonization, Identified in Community Health Centers in New York City.
Pardos de la Gandara, Maria; Raygoza Garay, Juan Antonio; Mwangi, Michael; Tobin, Jonathan N; Tsang, Amanda; Khalida, Chamanara; D'Orazio, Brianna; Kost, Rhonda G; Leinberger-Jabari, Andrea; Coffran, Cameron; Evering, Teresa H; Coller, Barry S; Balachandra, Shirish; Urban, Tracie; Parola, Claude; Salvato, Scott; Jenks, Nancy; Wu, Daren; Burgess, Rhonda; Chung, Marilyn; de Lencastre, Herminia; Tomasz, Alexander
In November 2011, The Rockefeller University Center for Clinical and Translational Science (CCTS), the Laboratory of Microbiology and Infectious Diseases, and Clinical Directors Network (CDN) launched a research and learning collaborative project with six community health centers in the New York City metropolitan area to determine the nature (clonal type) of community-acquired Staphylococcus aureus strains causing skin and soft tissue infections (SSTIs). Between November 2011 and March 2013, wound and nasal samples from 129 patients with active SSTIs suspicious for S. aureus were collected and characterized by molecular typing techniques. In 63 of 129 patients, the skin wounds were infected by S. aureus: methicillin-resistant S. aureus (MRSA) was recovered from 39 wounds and methicillin-sensitive S. aureus (MSSA) was recovered from 24. Most-46 of the 63-wound isolates belonged to the CC8/Panton-Valentine leukocidin-positive (PVL(+)) group of S. aureus clone USA300: 34 of these strains were MRSA and 12 were MSSA. Of the 63 patients with S. aureus infections, 30 were also colonized by S. aureus in the nares: 16 of the colonizing isolates were MRSA, and 14 were MSSA, and the majority of the colonizing isolates belonged to the USA300 clonal group. In most cases (70%), the colonizing isolate belonged to the same clonal type as the strain involved with the infection. In three of the patients, the identity of invasive and colonizing MRSA isolates was further documented by whole-genome sequencing.
Reich, P J; Boyle, M G; Hogan, P G; Johnson, A J; Wallace, M A; Elward, A M; Warner, B B; Burnham, C-A D; Fritz, S A
Methicillin-resistant Staphylococcus aureus (MRSA) infections cause significant morbidity and mortality in neonatal intensive care units (NICUs). We characterized the clinical and molecular epidemiology of MRSA strains colonizing NICU patients. Nasal MRSA isolates (n = 250, from 96 NICU patients) recovered through active surveillance from 2009 to 2014 were characterized with staphylococcal cassette chromosome mec (SCCmec) typing and detection of mupA (marker of high-level mupirocin resistance) and qacA/B (marker associated with chlorhexidine resistance). Factors associated with community-associated (CA-) or healthcare-associated (HA-) MRSA were evaluated. The overall prevalence of MRSA nasal colonization was 3.9%. Of 96 neonates in our retrospective cohort, 60 (63%) were colonized with CA-MRSA strains and 35 (36%) were colonized with HA-MRSA strains. Patients colonized with HA-MRSA were more likely to develop MRSA infections than patients colonized with CA-MRSA (13/35, 37% versus 8/60, 13%; p 0.007), although the interval from colonization to infection was shorter in CA-MRSA-colonized infants (median 0 days, range -1 to 4 versus HA-MRSA-colonized infants, 7 days, -1 to 43; p 0.005). Maternal peripartum antibiotics were associated with CA-MRSA colonization (adjusted odds ratio (aOR) 8.7; 95% CI 1.7-45.0); intubation and surgical procedures were associated with HA-MRSA colonization (aOR 7.8; 95% CI 1.3-47.6 and aOR 6.0; 95% CI 1.4-24.4, respectively). Mupirocin- and chlorhexidine-resistant MRSA was isolated from four and eight patients, respectively; carriage of a mupirocin-resistant strain precluded decolonization. CA-MRSA strains are prominent in the NICU and associated with distinct risk factors. Given community reservoirs for MRSA acquisition and transmission, novel infection prevention strategies are needed.
Haque, N; Bari, M S; Bilkis, L; Haque, N; Haque, S; Sultana, S
Staphylococcus aureus strains those are resistant to methicillin are referred to as Methicillin resistant Staphylococcus aureus. These express mecA gene to produce altered penicillin binding protein. At present Methicillin resistant Staphylococcus aureus has been increasing as a serious nosocomial and community pathogen having the property of multi drug resistan