# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 5948 | 0 | 1.0000 | Genetic Diversity and Resistome Analysis of Campylobacter lari Isolated from Gulls in Croatia. Campylobacter lari is a thermotolerant bacterium that sporadically causes gastrointestinal diseases in humans and can be found in wildlife and the environment. C. lari is an understudied species, especially in wild birds such as gulls. Gulls are potentially good carriers of pathogens due to their opportunistic behavior and tendency to gather in large flocks. During winter and their breeding period, 1753 gulls were captured, and cloacal swabs were taken to be tested for the presence of C. lari. From isolated bacteria, the DNA was sequenced, and sequence types (ST) were determined. Sixty-four swabs were positive for C. lari, and from those, forty-three different STs were determined, of which thirty-one were newly described. The whole genome was sequenced for 43 random isolates, and the same isolates were tested for antimicrobial susceptibility using the broth microdilution method to compare them to WGS-derived antimicrobial-resistant isolates. All the tested strains were susceptible to erythromycin, gentamicin, and chloramphenicol, and all were resistant to ciprofloxacin. Resistance to ciprofloxacin was attributed to a gyrA_2 T86V mutation. Genes connected to possible beta-lactam resistance (blaOXA genes) were also detected. | 2023 | 37627730 |
| 2961 | 1 | 0.9998 | Molecular Characterization and Antimicrobial Susceptibility of C. jejuni Isolates from Italian Wild Bird Populations. Poultry is considered a major reservoir of human campylobacteriosis. It also been reported that not only poultry, but also wild birds, are capable of carrying C. jejuni, thus demonstrating to be a risk of spreading the bacteria in the environment. To gain insight into the population structure and investigate the antimicrobial resistance genotypes and phenotypes, we analyzed a collection of 135 C. jejuni from 15 species of wild birds in Italy. MLST revealed the presence of 41 sequence types (STs) and 13 clonal complexes (CCs). ST-179 complex and the generalist ST-45 complex were the most prevalent. Core genome MLST revealed that C. jejuni from ST-45 complex clustered according to the bird species, unlike the ST-179 complex which featured 3 different species in the same cluster. Overall we found a moderate prevalence of resistance to tetracycline (12.5%), ciprofloxacin and nalidixic acid (10%). The novel ST isolated from one pigeon showed resistance to all the antibiotics tested. The ST-179 complex (33.3%) was identified with significantly higher nalidixic acid resistance relative to other tested STs. Nine AMR genes (tet(O), cmeA, cmeB, cmeC, cmeR, aad, blaOXA-61, blaOXA-184 and erm(B)) and 23S rRNA and gyrA-associated point mutations were also described, indicating a concordance level between genotypic and phenotypic resistance of 23.3%, 23.4% and of 37.5% for streptomycin, tetracycline and quinolones/fluoroquinolones, respectively. We recommend that particular attention should be given to wild birds as key sentinel animals for the ecosystem contamination surveillance. | 2020 | 32326051 |
| 1621 | 2 | 0.9997 | Antibiotic Resistance and Virulence Profiles of Escherichia coli Strains Isolated from Wild Birds in Poland. Wild animals are increasingly reported as carriers of antibiotic-resistant and pathogenic bacteria including Enterobacteriaceae. However, the role of free-living birds as reservoirs for potentially dangerous microbes is not yet thoroughly understood. In our work, we examined Escherichia coli strains from wild birds in Poland in relation to their antimicrobial agents susceptibility, virulence and phylogenetic affiliation. Identification of E. coli was performed using MALDI-TOF mass spectrometry. The antibiotic susceptibility of the isolates was determined by the broth microdilution method, and resistance and virulence genes were detected by PCR. E. coli bacteria were isolated from 32 of 34 samples. The strains were most often classified into phylogenetic groups B1 (50%) and A (25%). Resistance to tetracycline (50%), ciprofloxacin (46.8%), gentamicin (34.3%) and ampicillin (28.1%) was most frequently reported, and as many as 31.2% of E. coli isolates exhibited a multidrug resistance phenotype. Among resistance genes, sul2 (31.2% of isolates) and bla(TEM) (28.1%) were identified most frequently, while irp-2 (31.2%) and ompT (28.1%) were the most common virulence-associated genes. Five strains were included in the APEC group. The study indicates that wild birds can be carriers of potentially dangerous E. coli strains and vectors for the spread of resistant bacteria and resistance determinants in the environment. | 2021 | 34451523 |
| 2041 | 3 | 0.9997 | Carrier flies of multidrug-resistant Escherichia coli as potential dissemination agent in dairy farm environment. The life cycle of synanthropic flies and their behavior, allows them to serve as mechanical vectors of several pathogens. Given that flies can carry multidrug-resistant (MDR) bacteria, this study aimed to investigate the spread of genes of antimicrobial resistance in Escherichia coli isolated from flies collected in two dairy farms in Brazil. Besides antimicrobial resistance determinants, the presence of virulence genes related to bovine colibacillosis was also assessed. Of 94 flies collected, Musca domestica was the most frequently found in the two farms. We isolated 198 E. coli strains (farm A=135 and farm B=63), and >30% were MDR E. coli. We found an association between bla(TEM) and phenotypical resistance to ampicillin, or chloramphenicol, or tetracycline; and bla(CTX-M) and resistance to cefoperazone. A high frequency (86%) of phylogenetic group B1 among MDR strains and the lack of association between multidrug resistance and virulence factors suggest that antimicrobial resistance possibly is associated with the commensal bacteria. Clonal relatedness of MDR E. coli performed by Pulsed-Field Gel Electrophoresis showed wide genomic diversity. Different flies can carry clones, but with distinct antimicrobial resistance pattern. Sanger sequencing showed that the same class 1 integron arrangement is displayed by apparently unrelated strains, carried by different flies. Our conjugation results indicate class 1 integron transfer associated with tetracycline resistance. We report for the first time, in Brazil, that MDR E. coli is carried by flies in the milking environment. Therefore, flies can act as carriers for MDR strains and contribute to dissemination routes of antimicrobial resistance. | 2018 | 29758886 |
| 5582 | 4 | 0.9997 | Detection and prevalence of antimicrobial resistance genes in Campylobacter spp. isolated from chickens and humans. Campylobacter spp. are common pathogenic bacteria in both veterinary and human medicine. Infections caused by Campylobacter spp. are usually treated using antibiotics. However, the injudicious use of antibiotics has been proven to spearhead the emergence of antibiotic resistance. The purpose of this study was to detect the prevalence of antibiotic resistance genes in Campylobacter spp. isolated from chickens and human clinical cases in South Africa. One hundred and sixty one isolates of Campylobacter jejuni and Campylobacter coli were collected from chickens and human clinical cases and then screened for the presence of antimicrobial resistance genes. We observed a wide distribution of the tetO gene, which confers resistance to tetracycline. The gyrA genes that are responsible quinolone resistance were also detected. Finally, our study also detected the presence of the blaOXA-61, which is associated with ampicillin resistance. There was a higher (p < 0.05) prevalence of the studied antimicrobial resistance genes in chicken faeces compared with human clinical isolates. The tetO gene was the most prevalent gene detected, which was isolated at 64% and 68% from human and chicken isolates, respectively. The presence of gyrA genes was significantly (p < 0.05) associated with quinolone resistance. In conclusion, this study demonstrated the presence of gyrA (235 bp), gyrA (270 bp), blaOXA-61 and tetO antimicrobial resistance genes in C. jejuni and C. coli isolated from chickens and human clinical cases. This indicates that Campylobacter spp. have the potential of resistance to a number of antibiotic classes. | 2017 | 28582978 |
| 2037 | 5 | 0.9997 | Comparison of genotypic and phenotypic antimicrobial resistance profiles of Salmonella enterica isolates from poultry diagnostic specimens. The spread of antimicrobial-resistant bacteria is a significant concern, as it can lead to increased morbidity and mortality in both humans and animals. Whole-genome sequencing (WGS) is a powerful tool that can be used to conduct a comprehensive analysis of the genetic basis of antimicrobial resistance (AMR). We compared the phenotypic and genotypic AMR profiles of 97 Salmonella isolates derived from chicken and turkey diagnostic samples. We focused AMR analysis on 5 antimicrobial classes: aminoglycoside, beta-lactam, phenicol, tetracycline, and trimethoprim. The overall sensitivity and specificity of WGS in predicting phenotypic antimicrobial resistance in the Salmonella isolates were 93.4% and 99.8%, respectively. There were 16 disagreement instances, including 15 that were phenotypically resistant but genotypically susceptible; the other instance involved phenotypic susceptibility but genotypic resistance. Of the isolates examined, 67 of 97 (69%) carried at least 1 resistance gene, with 1 isolate carrying as many as 12 resistance genes. Of the 31 AMR genes analyzed, 16 were identified as aminoglycoside-resistance genes, followed by 4 beta-lactam-resistance, 3 tetracycline-resistance, 2 sulfonamide-resistance, and 1 each of fosfomycin-, quinolone-, phenicol-, trimethoprim-, bleomycin-, and colistin-resistance genes. Most of the resistance genes found were located on plasmids. | 2024 | 38571400 |
| 5935 | 6 | 0.9997 | Antibiotic resistance genes in anaerobic bacteria isolated from primary dental root canal infections. Fourty-one bacterial strains isolated from infected dental root canals and identified by 16S rRNA gene sequence were screened for the presence of 14 genes encoding resistance to beta-lactams, tetracycline and macrolides. Thirteen isolates (32%) were positive for at least one of the target antibiotic resistance genes. These strains carrying at least one antibiotic resistance gene belonged to 11 of the 26 (42%) infected root canals sampled. Two of these positive cases had two strains carrying resistance genes. Six out of 7 Fusobacterium strains harbored at least one of the target resistance genes. One Dialister invisus strain was positive for 3 resistance genes, and 4 other strains carried two of the target genes. Of the 6 antibiotic resistance genes detected in root canal strains, the most prevalent were blaTEM (17% of the strains), tetW (10%), and ermC (10%). Some as-yet-uncharacterized Fusobacterium and Prevotella isolates were positive for blaTEM, cfxA and tetM. Findings demonstrated that an unexpectedly large proportion of dental root canal isolates, including as-yet-uncharacterized strains previously regarded as uncultivated phylotypes, can carry antibiotic resistance genes. | 2012 | 23108290 |
| 5583 | 7 | 0.9997 | High prevalence of antimicrobial-resistant Escherichia coli from animals at slaughter: a food safety risk. BACKGROUND: There has been concern about the increase of antimicrobial resistant bacteria and protection of animal and public health, along with food safety. In the present study, we evaluate the incidence of antimicrobial resistance among 192 strains of Escherichia coli isolated from faecal samples of healthy food-producing animals at slaughter in Portugal. RESULTS: Ninety-seven % of the pig isolates, 74% from sheep and 55% from cattle were resistant to one or more antimicrobial agents, with the resistances to ampicillin, streptomycin, tetracycline and trimethoprim-sulfamethoxazole the most common phenotype detected. Genes encoding resistance to antimicrobial agents were detected in most of the resistant isolates. Ninety-three % of the resistant isolates were included in the A or B1 phylogenetic groups, and the virulence gene fimA (alone or in association with papC or aer genes) was detected in 137 of the resistant isolates. Five isolates from pigs belonging to phylogroup B2 and D were resistant to five different antimicrobial agents. CONCLUSION: Our data shows a high percentage of antibiotic resistance in E. coli isolates from food animals, and raises important questions in the potential impact of antibiotic use in animals and the possible transmission of resistant bacteria to humans through the food chain. | 2013 | 22836880 |
| 2696 | 8 | 0.9997 | Carriage of antimicrobial resistant Escherichia coli in adult intestinal flora. Knowledge of antibiotic resistance in bacteria strains colonizing healthy people is important for several reasons, one of which is that; these organisms form one of the largest reservoirs of resistant genes. Frequency of resistance to eleven different antimicrobial agents was examined in faecal flora of adults with no history of recent antimicrobial treatment. Using the disc diffusion sensitivity test, 106 strains of Escherichia coli were examined, 68% of these were resistant to tetracycline, and 57% were resistant to ampicillin and cotrimoxazole respectively. There was no resistance to cefuroxime but resistance to ceftazidime was 13%. Fifty six out of the eighty eight (64%) isolates, which showed any resistance, were resistant to three or more antimicrobials. The most common resistant pattern was to three drugs tetracycline, ampicillin and cotrimoxazole. Six strains were susceptible to all antibiotics. One strain of Escherichia coli was resistant to eight antimicrobials. Thirty per cent of the Escherichia coli were resistant to gentamicin. This study reveals a high prevalence of resistant bacteria in faecal flora of healthy adults. | 2002 | 12081343 |
| 2042 | 9 | 0.9997 | Genome Analysis of Multidrug-Resistant Escherichia coli Isolated from Poultry in Nigeria. Escherichia coli is one of the most common commensal bacteria of the gastrointestinal tract of humans and warm-blooded animals. Contaminated poultry can lead to disease outbreaks in consumers causing massive economic losses in the poultry industry. Additionally, commensal E. coli can harbor antibiotic resistance genes that can be transferred to other bacteria, including pathogens, in a colonized human host. In a previous study on antimicrobial resistance of E. coli from food animals from Nigeria, multidrug-resistant E. coli were detected. Three of those isolates were selected for further study using whole-genome sequencing due to the extensive drug resistance exhibited. All of the isolates carried the extended-spectrum β-lactamase (ESBL) genes, bla(CTX-M15) and bla(TEM-1), whereas one isolate harbored an additional ESBL, bla(OXA-1). All of the tetracycline-resistant isolates carried tet(A). The genes aac3-IIa and aacA4, conferring resistance to aminoglycosides, were identified in an E. coli isolate resistant to gentamicin and tobramycin. In two E. coli isolates, dfrA14, qnrS1, and sulII, were detected conferring resistance to trimethoprim, fluoroquinolones, and sulfonamides, respectively. The third isolate carried dfrA17, no fluoroquinolone resistance gene, an additional sulI gene, and a chloramphenicol resistance gene, catB3. Mutations in candidate genes conferring resistance to fosfomycin and fluoroquinolones were also detected. Several efflux systems were detected in all the E. coli isolates and virulence-associated genes related to serum resistance, motility, and adhesion. E. coli and non-E. coli origin prophages were also identified in the isolates. The results underline the higher resolution power of whole-genome sequencing for investigation of antimicrobial resistance, virulence, and phage in E. coli. | 2020 | 31509034 |
| 1658 | 10 | 0.9997 | Genetic characterization of extraintestinal Escherichia coli isolates from chicken, cow and swine. Phenotypic determination of antimicrobial resistance in bacteria is very important for diagnosis and treatment, but sometimes this procedure needs further genetic evaluation. Whole-genome sequencing plays a critical role in deciphering and advancing our understanding of bacterial evolution, transmission, and surveillance of antimicrobial resistance. In this study, whole-genome sequencing was performed on nineteen clinically extraintestinal Escherichia coli isolates from chicken, cows and swine and showing different antimicrobial susceptibility. A total of 44 different genes conferring resistance to 11 classes of antimicrobials were detected in 15 of 19 E. coli isolates (78.9%), and 22 types of plasmids were detected in 15/19 (78.9%) isolates. In addition, whole-genome sequencing of these 19 isolates identified 111 potential virulence factors, and 53 of these VFDB-annotated genes were carried by all these 19 isolates. Twelve different virulence genes were identified while the most frequent ones were gad (glutamate decarboxylase), iss (increased serum survival) and lpfA (long polar fimbriae). All isolates harbored at least one of the virulence genes. The findings from comparative genomic analyses of the 19 diverse E. coli isolates in this study provided insights into molecular basis of the rising multi-drug resistance in E. coli. | 2018 | 30019301 |
| 2927 | 11 | 0.9997 | Aeromonas hydrophila from marketed mullet (Mugil cephalus) in Egypt: PCR characterization of β-lactam resistance and virulence genes. AIMS: Aeromonas hydrophila has been isolated from various fish species in Egypt and is known to carry virulence and antimicrobial resistance genes, which pose a risk for public health. The aim of the present study is to report, for the first time, the infection of mullet (Mugil cephalus) with A. hydrophila and to clarify the potential association between antimicrobial resistance and virulence traits encoded in A. hydrophila. METHODS AND RESULTS: In this study, the occurrence of A. hydrophila in marketed mullet and the antimicrobial resistance phenotypes of these isolates were determined. Aeromonas hydrophila isolates were screened for the presence of virulence and β-lactam resistance genes; the correlation between both gene groups was also investigated. The infection rate of examined mullet with A. hydrophila was 37% (50/135). The highest antimicrobial resistance was detected to cefoxitin (100%), followed by ampicillin (84%), ceftazidime (56%) and cefotaxime (40%). Only 4% of the isolates were resistant to erythromycin; 6% were resistant to both gentamicin and kanamycin with no resistance to ciprofloxacin. Variable frequencies of virulence and β-lactam resistance genes were evident from PCR, where aerA and bla(TEM) predominated. The study also indicated a general weak positive correlation (R = 0·3) between both virulence and β-lactam resistance genes. Some of the studied virulence genes (e.g. aerA:hlyA and hlyA:ast) were found to correlate positively. CONCLUSIONS: The presence of virulence and resistance genes in A. hydrophila from food sources poses a serious threat to public health. To our knowledge, this is the first report describing the occurrence of A. hydrophila in mullet and highlighting the coexistence of virulence and β-lactam resistance genes encoded by these bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: These data provide insights into the potential association of antimicrobial resistance and virulence genes in A. hydrophila from marketed mullet in Egypt, which could pose threats to humans even if a weak positive correlation exists between both genes. | 2018 | 29453863 |
| 2910 | 12 | 0.9997 | Phenotypic and genotypic characterization of tetracycline and minocycline resistance in Clostridium perfringens. The aim of this study was to determine the incidence of tetracycline resistance and the prevalence of tetracycline-resistance genes in strains of Clostridium perfringens isolated from different sources between 1994 and 2005. Susceptibility to tetracycline and minocycline in strains from humans (35 isolates), chickens (15 isolates), food (21 isolates), soil (16 isolates) and veterinary sources (6 isolates) was determined, and tetracycline-resistance genes were detected. Resistance was most common in strains isolated from chickens, followed by those from soils, clinical samples and foods. The most highly resistant strains were found among clinical and food isolates. tetA(P) was the most common resistance gene, and along with tetB(P) was found in all resistant strains and some sensitive strains. One tetracycline-resistant food isolate had an intact tet(M) gene. However, PCR fragments of 0.4 or 0.8 kb with high degrees of identity to parts of the tet(M) sequences of other bacteria were found, mainly in clinical isolates, and often in isolates with tetB(P). No correlation between level of sensitivity to tetracycline or minocycline and the presence of tetA(P), tetB(P) or part of tet(M) was found. The presence of part of tet(M) in some strains of C. perfringens containing tetB(P) may have occurred by recent gene transfer. | 2010 | 20661548 |
| 2960 | 13 | 0.9997 | Antibiotic resistance, virulence genes, and phylogenetic groups of bacteria isolated from wild passerine birds in Iran. Wild passerine birds may serve as environmental reservoirs and as vectors for the long-distance dispersal of microorganisms and resistance determinants. However, there is no much knowledge on pathogenic bacteria in wild birds in Iran. The present study aimed to analyze antibiotic resistance in wild passerine birds collected from the northeast region of Iran as the rich breeding bird fauna with a special focus on Escherichia coli virulence, integron, and phylogenetic groups. A total of 326 isolates were collected and identified from the cloaca of wild birds using a swab. The results showed a high percentage of resistance to tetracycline (45.8%) and ampicillin (26.7%). The resistance genes, tet(A), tet(B), tet(M), and tet(L) were detected in tetracycline-resistant isolates, while the blaTEM gene was the most prevalent in ampicillin-resistant isolates (38.6%). Out of the 129 E. coli isolates examined, 99 isolates were found to have virulence gene, with the highest prevalence of the fimbriae (fimH) gene (22.4%). Additionally, the E. coli strains were most often classified into phylogenetic groups B1 (48.8%) followed by B2 (19.3%). Also, the highest average frequency of class 1 integron was detected among our isolates. Results indicated that wild birds are reservoirs of multidrug resistance and virulence genes that may have the potential to be transferred to other organisms, including humans. | 2024 | 39298116 |
| 2038 | 14 | 0.9997 | Salmonella enterica Serotype 4,[5],12:i:- in Swine in the United States Midwest: An Emerging Multidrug-Resistant Clade. BACKGROUND: Salmonella 4,[5],12:i:-, a worldwide emerging pathogen that causes many food-borne outbreaks mostly attributed to pig and pig products, is expanding in the United States. METHODS: Whole-genome sequencing was applied to conduct multiple comparisons of 659 S. 4,[5],12:i:- and 325 Salmonella Typhimurium from different sources and locations (ie, the United States and Europe) to assess their genetic heterogeneity, with a focus on strains recovered from swine in the US Midwest. In addition, the presence of resistance genes and other virulence factors was detected and the antimicrobial resistance phenotypes of 50 and 22 isolates of livestock and human origin, respectively, was determined. RESULTS: The S. 4,5,12:i:- strains formed two main clades regardless of their source and geographic origin. Most (84%) of the US isolates recovered in 2014-2016, including those (48 of 51) recovered from swine in the US Midwest, were part of an emerging clade. In this clade, multiple genotypic resistance determinants were predominant, including resistance against ampicillin, streptomycin, sulfonamides, and tetracyclines. Phenotypic resistance to enrofloxacin (11 of 50) and ceftiofur (9 of 50) was found in conjunction with the presence of plasmid-mediated resistance genes (qnrB19/qnrB2/qnrS1 and blaCMY-2/blaSHV-12, respectively). Higher similarity was also found between S. 4,[5],12:i:- from the emerging clade and S. Typhimurium from Europe than with S. Typhimurium from the United States. CONCLUSIONS: Salmonella 4,[5],12:i:- currently circulating in swine in the US Midwest are likely to be part of an emerging multidrug-resistant clade first reported in Europe, and can carry plasmid-mediated resistance genes that may be transmitted horizontally to other bacteria, and thus may represent a public health concern. | 2018 | 29069323 |
| 5921 | 15 | 0.9997 | Prevalence of tetracycline resistance genes in oral bacteria. Tetracycline is a broad-spectrum antibiotic used in humans, animals, and aquaculture; therefore, many bacteria from different ecosystems are exposed to this antibiotic. In order to determine the genetic basis for resistance to tetracycline in bacteria from the oral cavity, saliva and dental plaque samples were obtained from 20 healthy adults who had not taken antibiotics during the previous 3 months. The samples were screened for the presence of bacteria resistant to tetracycline, and the tetracycline resistance genes in these isolates were identified by multiplex PCR and DNA sequencing. Tetracycline-resistant bacteria constituted an average of 11% of the total cultivable oral microflora. A representative 105 tetracycline-resistant isolates from the 20 samples were investigated; most of the isolates carried tetracycline resistance genes encoding a ribosomal protection protein. The most common tet gene identified was tet(M), which was found in 79% of all the isolates. The second most common gene identified was tet(W), which was found in 21% of all the isolates, followed by tet(O) and tet(Q) (10.5 and 9.5% of the isolates, respectively) and then tet(S) (2.8% of the isolates). Tetracycline resistance genes encoding an efflux protein were detected in 4.8% of all the tetracycline-resistant isolates; 2.8% of the isolates had tet(L) and 1% carried tet(A) and tet(K) each. The results have shown that a variety of tetracycline resistance genes are present in the oral microflora of healthy adults. This is the first report of tet(W) in oral bacteria and the first report to show that tet(O), tet(Q), tet(A), and tet(S) can be found in some oral species. | 2003 | 12604515 |
| 5555 | 16 | 0.9997 | New sequence types and multidrug resistance among pathogenic Escherichia coli isolates from coastal marine sediments. The spread of antibiotic-resistant microorganisms is widely recognized, but data about their sources, presence, and significance in marine environments are still limited. We examined 109 Escherichia coli strains from coastal marine sediments carrying virulence genes for antibiotic susceptibility, specific resistance genes, prevalence of class 1 and 2 integrons, and sequence type. Antibiotic resistance was found in 35% of strains, and multiple resistances were found in 14%; the resistances detected most frequently were against tetracycline (28%), ampicillin (16.5%), trimethoprim-sulfamethoxazole (13%), and streptomycin (7%). The highest prevalence of resistant strains was in phylogenetic group A, whereas phylogroup B2 exhibited a significantly lower frequency than all the other groups. Sixty percent of multiresistant strains harbored class 1 or 2 integrase genes, and about 50% carried resistance genes (particularly dfrA and aadA) linked to a class 1 integron. Multilocus sequence typing of 14 selected strains identified eight different types characteristic of extraintestinal pathogens and three new allelic combinations. Our data suggest that coastal marine sediment may be a suitable environment for the survival of pathogenic and antimicrobial-resistant E. coli strains capable of contributing to resistance spread via integrons among benthic bacteria, and they highlight a role for these strains in the emergence of new virulent genotypes. | 2012 | 22447595 |
| 1659 | 17 | 0.9997 | Escherichia coli isolates from extraintestinal organs of livestock animals harbour diverse virulence genes and belong to multiple genetic lineages. Escherichia coli, the most common cause of bacteraemia in humans in the UK, can also cause serious diseases in animals. However the population structure, virulence and antimicrobial resistance genes of those from extraintestinal organs of livestock animals are poorly characterised. The aims of this study were to investigate the diversity of these isolates from livestock animals and to understand if there was any correlation between the virulence and antimicrobial resistance genes and the genetic backbone of the bacteria and if these isolates were similar to those isolated from humans. Here 39 E. coli isolates from liver (n=31), spleen (n=5) and blood (n=3) of cattle (n=34), sheep (n=3), chicken (n=1) and pig (n=1) were assigned to 19 serogroups with O8 being the most common (n=7), followed by O101, O20 (both n=3) and O153 (n=2). They belong to 29 multi-locus sequence types, 20 clonal complexes with ST23 (n=7), ST10 (n=6), ST117 and ST155 (both n=3) being most common and were distributed among phylogenetic group A (n=16), B1 (n=12), B2 (n=2) and D (n=9). The pattern of a subset of putative virulence genes was different in almost all isolates. No correlation between serogroups, animal hosts, MLST types, virulence and antimicrobial resistance genes was identified. The distributions of clonal complexes and virulence genes were similar to other extraintestinal or commensal E. coli from humans and other animals, suggesting a zoonotic potential. The diverse and various combinations of virulence genes implied that the infections were caused by different mechanisms and infection control will be challenging. | 2012 | 22766078 |
| 1948 | 18 | 0.9997 | Identification and Characterization of Cefotaxime Resistant Bacteria in Beef Cattle. Third-generation cephalosporins are an important class of antibiotics that are widely used in treatment of serious Gram-negative bacterial infections. In this study, we report the isolation of bacteria resistant to the third-generation cephalosporin cefotaxime from cattle with no previous cefotaxime antibiotic exposure. The prevalence of cefotaxime-resistant bacteria was examined by a combination of culture based and molecular typing methods in beef cattle (n = 1341) from 8 herds located in North Central Florida. The overall prevalence of cefotaxime-resistant bacteria was 15.8% (95% CI: 13.9, 17.8), varied between farms, and ranged from 5.2% to 100%. A subset of isolates (n = 23) was further characterized for the cefotaxime minimum inhibitory concentration (MIC) and antibiotic susceptibility against 10 different antibiotics, sequencing of nine β- lactamase genes, and species identification by 16S rRNA sequencing. Most of the bacterial isolates were resistant to cefotaxime (concentrations, > 64 μg/mL) and showed high levels of multi-drug resistance. Full length 16S rRNA sequences (~1300 bp) revealed that most of the isolates were not primary human or animal pathogens; rather were more typical of commensal, soil, or other environmental origin. Six extended spectrum β-lactamase (ESBL) genes identical to those in clinical human isolates were identified. Our study highlights the potential for carriage of cefotaxime resistance (including "human" ESBL genes) by the bacterial flora of food animals with no history of cefotaxime antibiotic exposure. A better understanding of the origin and transmission of resistance genes in these pre-harvest settings will be critical to development of strategies to prevent the spread of antimicrobial resistant microorganisms to hospitals and communities. | 2016 | 27642751 |
| 2692 | 19 | 0.9997 | Tetracycline Resistance Genes in Campylobacter jejuni and C. coli Isolated From Poultry Carcasses. BACKGROUND: Campylobacter is one of the leading bacterial species causing foodborne illnesses in humans. Antimicrobial agents have been extensively used for treatment of Campylobacter infections; but in the recent years, both animal and human isolates of this bacterium have shown resistance to several antibiotics such as tetracycline. OBJECTIVES: The aim of this study was to investigate the presence of genetic determinants of tetracycline resistance in Campylobacter spp. recovered from poultry carcasses in Shiraz, Iran. MATERIALS AND METHODS: Eighty-three thermophilic Campylobacter spp. Isolates were first identified based on multiplex polymerase chain reaction (PCR) and then screened for presence of tetracycline resistance genes (tet (A), tet (B), tet (O) and te (S)) by PCR. RESULTS: The overall prevalence of Campylobacter jejuni and C. coli among the examined isolates was 51.8% and 48.2%, respectively. Tetracycline resistance genes of tet (B) and tet (S) were not seen among these Campylobacter spp. Isolates, whereas the most common tet gene identified was tet (O), found in 83.1% (69/83) of all the isolates. The tet (O) gene sequence comparison between C. jejuni and C. coli showed 100% similarity and these sequences (JX853721and JX853722) were also identical to the homologous sequences of other strains of Campylobacter spp. existing in the GenBank databases. In addition, tet (A) was found in 18% (15/83) of Campylobacter spp. isolates. To our knowledge, this represents the first report of tet (A) in Campylobacter spp. There was 100% homology between the sequences of tet (A) from this study (JX891463 and JX891464) and the tet (A) sequences mentioned for other bacteria in the GenBank databases. CONCLUSIONS: The high prevalence of tet (O) resistance gene along with new detection of tet (A) resistance gene in Campylobacter spp. isolated from poultry carcasses revealed an extensive tetracycline resistance among Campylobacter isolates from poultry in Iran. It emphasized the need for cautious use of tetracycline in poultry production to decrease the extension of tetracycline-resistant Campylobacter spp. | 2014 | 25485062 |