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129500.9984Phenotypic and genotypic characterisation of antimicrobial resistance in faecal bacteria from 30 Giant pandas. To study the prevalence of antimicrobial resistance in faecal bacteria from Giant pandas in China, 59 isolates were recovered from faecal pats of 30 Giant pandas. Antimicrobial susceptibility testing of the isolates was performed by the standardised disk diffusion method (Kirby-Bauer). Of the 59 study isolates, 32.20% were resistant to at least one antimicrobial and 16.95% showed multidrug-resistant phenotypes. Thirteen drug resistance genes [aph(3')-IIa, aac(6')-Ib, ant(3'')-Ia, aac(3)-IIa, sul1, sul2, sul3, tetA, tetC, tetM, cat1, floR and cmlA] were analysed using four primer sets by multiplex polymerase chain reaction (PCR). The detection frequency of the aph(3')-IIa gene was the highest (10.17%), followed by cmlA (8.47%). The genes aac(6')-Ib, sul2 and tetA were not detected. PCR products were confirmed by DNA sequence analysis. The results revealed that multidrug resistance was widely present in bacteria isolated from Giant pandas.200919168331
123610.9983Molecular characterization of antimicrobial resistance in Gram-negative bacteria isolated from bovine mastitis in Egypt. The aim of this study was to characterize the genetic basis of multidrug resistance in Gram-negative bacteria isolated from bovine mastitis cases in Egypt. Multidrug resistance phenotypes were found in 34 of 112 (30.4%) Gram-negative bacterial isolates, which harbored at least one antimicrobial resistance gene. The most prevalent multidrug-resistant (MDR) species were Enterobacter cloacae (8 isolates, 7.1%), Klebsiella pneumoniae (7 isolates, 6.3%), Klebsiella oxytoca (7 isolates, 6.3%), Escherichia coli (5 isolates, 4.5%), and Citrobacter freundii (3 isolates, 2.7%). The most commonly observed resistance phenotypes were against ampicillin (97.0%), streptomycin (94.1%), tetracycline (91.2%), trimethoprim-sulfamethoxazole (88.2%), nalidixic acid (85.3%), and chloramphenicol (76.5%). Class 1 integrons were detected in 28 (25.0%) isolates. The gene cassettes within class 1 integrons included those encoding resistance to trimethoprim (dfrA1, dfrA5, dfrA7, dfrA12, dfrA15, dfrA17, and dfrA25), aminoglycosides (aadA1, aadA2, aadA5, aadA7, aadA12, aadA22, and aac(3)-Id), chloramphenicol (cmlA), erythromycin (ereA2), and rifampicin (arr-3). Class 2 integrons were identified in 6 isolates (5.4%) with three different profiles. Furthermore, the β-lactamase encoding genes, bla(TEM), bla(SHV), bla(CTX-M), and bla(OXA), the plasmid-mediated quinolone resistance genes, qnr and aac(6)-Ib-cr, and the florfenicol resistance gene, floR, were also identified. To the best of our knowledge, the results identified class 2 integrons, qnr and aac(6)-Ib-cr from cases of mastitis for the first time. This is the first report of molecular characterization for antimicrobial resistance in Gram-negative bacteria isolated from bovine mastitis in Africa.201121338385
131120.9982Prevalence and Molecular Characterization of Antimicrobial Resistance in Escherichia coli Isolated from Raw Milk and Raw Milk Cheese in Egypt. The goal of this study was to examine antimicrobial resistance and characterize the implicated genes in 222 isolates of Escherichia coli from 187 samples of raw milk and the two most popular cheeses in Egypt. E. coli isolates were tested for susceptibility to 12 antimicrobials by a disk diffusion method. Among the 222 E. coli isolates, 66 (29.7%) were resistant to one or more antimicrobials, and half of these resistant isolates showed a multidrug resistance phenotype (resistance to at least three different drug classes). The resistance traits were observed to tetracycline (27.5%), ampicillin (18.9%), streptomycin (18.5%), sulfamethoxazole-trimethoprim (11.3%), cefotaxime (4.5%), kanamycin (4.1%), ceftazidime (3.6%), chloramphenicol (2.3%), nalidixic acid (1.8%), and ciprofloxacin (1.4%). No resistance to fosfomycin and imipenem was observed. Tetracycline resistance genes tetA, tetB, and tetD were detected in 53 isolates, 9 isolates, and 1 isolate, respectively, but tetC was not detected. Aminoglycoside resistance genes strA, strB, aadA, and aphA1 were detected in 41, 41, 11, and 9 isolates, respectively. Sulfonamide resistance genes sul1, sul2, and sul3 were detected in 7, 25, and 3 isolates, respectively. Of 42 ampicillin-resistant isolates, bla(TEM), bla(CTX-M), and bla(SHV) were detected in 40, 9, and 3 isolates, respectively, and 10 (23.8%) ampicillin-resistant isolates were found to produce extended-spectrum β-lactamase. Each bla gene of extended-spectrum β-lactamase-producing E. coli was further subtyped to be bla(CTX-M-15), bla(CTX-M-104), bla(TEM-1), and bla(SHV-12). The class 1 integron was also detected in 28 resistant isolates, and three different patterns were obtained by PCR-restriction fragment length polymorphism. Sequencing analysis of the variable region revealed that four isolates had dfrA12/orfF/aadA2, two had aadA22, and one had dfrA1/aadA1. These data suggest that antimicrobial-resistant E. coli are widely distributed in the milk production and processing environment in Egypt and may play a role in dissemination of antimicrobial resistance to other pathogenic and commensal bacteria.201829323530
129630.9982Prevalence and antimicrobial resistance of Salmonellaisolates from goose farms in Northeast China. BACKGROUND: Salmonella is one of the most important enteric pathogenic bacteria that threatened poultry health. AIMS: This study aimed to investigate the prevalence and antimicrobial resistance of Salmonella isolates in goose farms. METHODS: A total of 244 cloacal swabs were collected from goose farms to detect Salmonella in Northeast China. Antimicrobial susceptibility, and resistance gene distribution of Salmonella isolates were investigated. RESULTS: Twenty-one Salmonella isolates were identified. Overall prevalence of Salmonella in the present study was 8.6%. Among the Salmonella isolates, the highest resistance frequencies belonged to amoxicillin (AMX) (85.7%), tetracycline (TET) and trimethoprim/sulfamethoxazole (SXT) (81%), followed by chloramphenicol (CHL) (76.2%), florfenicol (FLO) (71.4%), kanamycin (KAN) (47.6%), and gentamycin (GEN) (38.1%). Meanwhile, only 4.8% of the isolates were resistant to ciprofloxacin (CIP) and cefotaxime (CTX). None of the isolates was resistant to cefoperazone (CFP) and colistin B (CLB). Twenty isolates (95%) were simultaneously resistant to at least two antimicrobials. Ten resistance genes were detected among which the bla (TEM-1), cmlA, aac(6')-Ib-cr, sul1, sul2, sul3, and mcr-1.1 were the most prevalent, and presented in all 21 isolates followed by tetB (20/21), qnrB (19/21), and floR (15/21). CONCLUSION: Results indicated that Salmonella isolates from goose farms in Northeast China exhibited multi-drug resistance (MDR), harboring multiple antimicrobial resistance genes. Our results will be useful to design prevention and therapeutic strategies against Salmonella infection in goose farms.202033584841
132440.9982Molecular characterization of antimicrobial resistance in enterococci and Escherichia coli isolates from European wild rabbit (Oryctolagus cuniculus). A total of 44 Escherichia coli and 64 enterococci recovered from 77 intestinal samples of wild European rabbits in Portugal were analyzed for resistance to antimicrobial agents. Resistance in E. coli isolates was observed for ampicillin, tetracycline, sulfamethoxazole/trimethoprim, streptomycin, gentamicin, tobramycin, nalidixic acid, ciprofloxacin and chloramphenicol. None of the E. coli isolates produced extended-spectrum beta-lactamases (ESBLs). The bla(TEM), aadA, aac(3)-II, tet(A) and/or tet(B), and the catA genes were demonstrated in all ampicillin, streptomycin, gentamicin, tetracycline, and chloramphenicol-resistant isolates respectively, and the sul1 and/or sul2 and/or sul3 genes in 4 of 5 sulfamethoxazole/trimethoprim resistant isolates. Of the enterococcal isolates, Enterococcus faecalis was the most prevalent detected species (39 isolates), followed by E. faecium (21 isolates) and E. hirae (4 isolates). More than one-fourth (29.7%) of the isolates were resistant to tetracycline; 20.3% were resistant to erythromycin, 14.1% were resistant to ciprofloxacin and 10.9% were resistant to high-level-kanamycin. Lower level of resistance (<10%) was detected for ampicillin, quinupristin/dalfopristin and high-level-gentamicin, -streptomycin. No vancomycin-resistance was detected in the enterococci isolates. Resistance genes detected included aac(6')-aph(2''), ant(6)-Ia, tet(M) and/or tet(L) in all gentamicin, streptomycin and tetracycline-resistant isolates respectively. The aph(3')-IIIa gene was detected in 6 of 7 kanamycin-resistant isolates, the erm(B) gene in 11 of 13 erythromycin-resistant isolates and the vat(D) gene in the quinupristin/dalfopristin-resistant E. faecium isolate. This survey showed that faecal bacteria such as E. coli and enterococci of wild rabbits could be a reservoir of antimicrobial resistance genes.201020624632
111450.9982Third-Generation Cephalosporin Resistance in Intrinsic Colistin-Resistant Enterobacterales Isolated from Retail Meat. Consumption of retail meat contaminated with antimicrobial-resistant (AMR) bacteria is a common route for transmitting clinically relevant resistant bacteria to humans. Here, we investigated the genotypic and phenotypic resistance profiles of intrinsic colistin-resistant (ICR) Enterobacterales isolated from retail meats. ICR Enterobacterales were isolated from 103 samples of chicken, 103 samples of pork, and 104 samples of beef purchased from retail shops in Japan, using colistin-containing media, and their antimicrobial susceptibility was examined. Serratia spp. (440 isolates) showed resistance to cefotaxime (19 isolates, 4.3%), tetracycline (15 isolates, 3.4%), and other antimicrobials (<1%). Hafnia spp. (136) showed resistance to cefotaxime (12 isolates, 8.6%), ceftazidime (four isolates, 2.9%), and tetracycline (two isolates, 1.4%). Proteus spp. (39) showed resistance to chloramphenicol (four isolates, 10.3%), sulfamethoxazole-trimethoprim (four isolates, 10.3%), cefotaxime (two isolates, 5.1%), kanamycin (two isolates, 5.1%), and gentamicin (one isolate, 2.6%). Cedecea spp. (22) were resistant to tetracycline (two isolates, 9.1%) whereas Morganella spp. (11) were resistant to tetracycline (four isolates, 36.4%) and chloramphenicol (one isolate, 9.2%). The resistance genes bla(fonA), bla(ACC), and bla(DHA) were detected in cefotaxime-resistant Serratia spp., Hafnia spp., and Morganella spp. isolates, respectively. This emergence of antimicrobial resistance in ICR Enterobacterales may pose a public health risk.202134943649
131060.9981Antimicrobial Resistance of Escherichia fergusonii Isolated from Broiler Chickens. The objective of this study was to investigate the antibiotic resistance of Escherichia fergusonii isolated from commercial broiler chicken farms. A total of 245 isolates from cloacal and cecal samples of 28- to 36-day-old chickens were collected from 32 farms. Isolates were identified using PCR, and their susceptibility to 16 antibiotics was determined by disk diffusion assay. All isolates were susceptible to meropenem, amikacin, and ciprofloxacin. The most common resistances were against ampicillin (75.1%), streptomycin (62.9%), and tetracycline (57.1%). Of the 184 ampicillin-resistant isolates, 127 were investigated using a DNA microarray carrying 75 probes for antibiotic resistance genetic determinants. Of these 127 isolates, the β-lactamase blaCMY2, blaTEM, blaACT, blaSHV, and blaCTX-M-15 genes were detected in 120 (94.5%), 31 (24.4%), 8 (6.3%), 6 (4.7%), and 4 (3.2%) isolates, respectively. Other detected genes included those conferring resistance to aminoglycosides (aadA1, strA, strB), trimethoprims (dfrV, dfrA1), tetracyclines (tetA, tetB, tetC, tetE), and sulfonamides (sul1, sul2). Class 1 integron was found in 35 (27.6%) of the ampicillin-resistant isolates. However, our data showed that the tested E. fergusonii did not carry any carbapenemase blaOXA genes. Pulsed-field gel electrophoresis revealed that the selected ampicillin-resistant E. fergusonii isolates were genetically diverse. The present study indicates that the monitoring of antimicrobial-resistant bacteria should include enteric bacteria such as E. fergusonii, which could be a reservoir of antibiotic resistance genes. The detection of isolates harboring extended-spectrum β-lactamase genes, particularly blaCTX-M-15, in this work suggests that further investigations on the occurrence of such genes in broilers are warranted.201627296596
137570.9981Characterization of integrons and their cassettes in Escherichia coli and Salmonella isolates from poultry in Korea. Ninety-nine Escherichia coli and 33 Salmonella isolates were assessed for antimicrobial susceptibility (disc diffusion test). Sulfonamide and tetracycline resistance genes were identified through PCR, and class 1 and class 2 integrons with resistance gene cassettes were identified with PCR followed by sequencing. Salmonella (63.6%) and E. coli (85.8%) isolates were multidrug resistant (resistance to 3 or more antimicrobials), and the highest incidences of resistance were observed for tetracycline, nalidixic acid, and sulfamethoxazole. The sul1, sul2, tetA, and tetB resistance determinant genes were predominant in E. coli, whereas only sul2 and tetA were identified in Salmonella isolates. In the E. coli isolates, 54 (54.5%) class 1 integrons, 6 (6.1%) class 2 integrons, and 5 (5.1%) class 1 and class 2 integrons together were detected, whereas only 3 (9.1%) integrons were found in the Salmonella serovars. Around 87% of the integrons in E. coli harbored resistance gene cassettes conferring resistance to streptomycin/spectinomycin (aadA, aminoglycoside resistance gene), trimethoprim (dfrA, dihydrofolate reductase gene), streptothricin [sat1 and sat2 (streptothricin acetyltransferase), and estX (putative esterases)]. The most common gene cassettes were aadA1+dfrA1 and dfrA1+sat2+aadA1 in class 1 and class 2 integrons, respectively. Other cassettes including aadA5+dfrA7, dfrA12+aadA2, aadA2+aadA1+dfrA12, and aadA5+aadA2/dfrA7 were also identified. Among the Salmonella serovars, Salmonella Malmoe harbored aadA1+dfrA1 and dfrA12+sat2+aadA1 genes. The aadA1, aadA2, sat2, and dfrA1 had wide variation in similarity among themselves and from previously reported genes worldwide. The diverse gene cassettes could be responsible for the prominent resistance profiles observed and a potential source for dissemination of antimicrobial resistance determinants to other bacteria.201324135609
117080.9981Mechanisms of antibiotic resistance in Escherichia coli isolates obtained from healthy children in Spain. Antibiotic resistance and mechanisms involved were studied in Escherichia coli isolates from fecal samples of healthy children. Fifty fecal samples were analyzed, and one colony per sample was recovered and identified by biochemical and molecular tests. Forty-one E. coli isolates were obtained (82%). MIC testing was performed by agar dilution with 18 antibiotics, and the mechanisms of resistance were analyzed. Ampicillin resistance was detected in 24 isolates (58.5%), and blaTEM, blaSHV, and blaOXA type genes were studied by PCR and sequencing. The following beta-lactamases were detected (number of isolates): TEM (20), SHV-1 (1), and OXA-30 (1). The number of aminoglycoside-resistant isolates detected was as follows: streptomycin (15), tobramycin (1), gentamicin (1), and kanamycin (4). The aac(3)-IV gene was detected in the only gentamicin-resistant isolate. Nine (22%) and 2 (5%) isolates showed nalidixic acid (NALR) and ciprofloxacin resistance (CIPR), respectively. Mutations in GyrA and ParC proteins were shown in both NAL(R)-CIP(R) isolates and were the following: (1) GyrA (S83L + D87N), ParC (S801); and (2) GyrA (S83L + A84P), ParC (S80I + A108V). A single mutation in the S83 codon of the gyrA gene was found in the remaining seven NAL(R)-CIP(S) isolates. Tetracycline resistance was identified in 21 isolates (51%) and the following resistance genes were found (number of isolates): tetA (12), tetB (5), and tetD (1). Chloramphenicol resistance was detected in five isolates (12%). These results show that the intestinal tract of healthy children constitutes a reservoir of resistant bacteria and resistance genes.200212523629
130990.9981Phenotypic and genotypic antimicrobial resistance patterns of Escherichia coli isolated from dairy cows with mastitis. Pulsed field gel electrophoresis (PFGE) patterns, susceptibility to 26 antimicrobial agents used in veterinary and human medicine, and prevalence of antimicrobial resistance genes of Escherichia coli isolated from cows with mastitis were evaluated. Among 135 E. coli isolates, PFGE analysis revealed 85 different genetic patterns. All E. coli were resistant to two or more antimicrobials in different combinations. Most E. coli were resistant to antimicrobials used in veterinary medicine including ampicillin (98.4%, >or=32 microg/ml) and many E. coli were resistant to streptomycin (40.3%, >or=64 microg/ml), sulfisoxazole (34.1%, >or=512 microg/ml), and tetracycline (24.8%, >or=16 microg/ml). Most E. coli were resistant to antimicrobials used in human medicine including aztreonam (97.7%, >or=32 microg/ml) and cefaclor (89.9%, >or=32 microg/ml). Some E. coli were resistant to nitrofurantoin (38%, >or=128 microg/ml), cefuroxime (22.5%, >or=32 microg/ml), fosfomycin (17.8%, >or=256 microg/ml). All E. coli were susceptible to ciprofloxacin and cinoxacin. Almost 97% (123 of 127) of ampicillin-resistant isolates carried ampC. Eleven of 52 (21.2%) streptomycin-resistant isolates carried strA, strB and aadA together and 29 streptomycin-resistant isolates (55.8%) carried aadA alone. Among 44 sulfisoxazole-resistant E. coli, 1 isolate (2.3%) carried both sulI and sulII, 12 (27.3%) carried sulI and 10 (22.7%) isolates carried sulII. Among 32 tetracycline-resistant isolates, 14 (43.8%) carried both tetA and tetC and 14 (43.8%) carried tetC. Results of this study demonstrated that E. coli from cows with mastitis were genotypically different, multidrug resistant and carried multiple resistance genes. These bacteria can be a reservoir for antimicrobial resistance genes and can play a role in the dissemination of antimicrobial resistance genes to other pathogenic and commensal bacteria in the dairy farm environment.200717544234
1315100.9981Neonatal calf diarrhea: A potent reservoir of multi-drug resistant bacteria, environmental contamination and public health hazard in Pakistan. Though emergence of multi-drug resistant bacteria in the environment is a demonstrated worldwide phenomenon, limited research is reported about the prevalence of resistant bacteria in fecal ecology of neonatal calf diarrhea (NCD) animals in Pakistan. The present study aimed to identify and assess the prevalence of bacterial pathogens and their resistance potential in the fecal ecology of NCD diseased animals of Pakistan. The presence of antibiotic resistance genes (bla(TEM), bla(NDM-1), bla(CTX-M), qnrS) was also investigated. A total of 51 bacterial isolates were recovered from feces of young diarrheic animals (n = 11), collected from 7 cities of Pakistan and identified on the basis of 16S rRNA gene sequence and phylogenetic analysis. Selected isolates were subjected to antimicrobial susceptibility by disc diffusion method while polymerase chain reaction (PCR) was used to characterize the bla(TEM), bla(NDM-1), bla(CTX-M), qnrS and mcr-1 antibiotic resistance genes. Based on the 16S rRNA gene sequences (Accession numbers: LC488898 to LC488948), all isolates were identified that belonged to seventeen genera with the highest prevalence rate for phylum Proteobacteria and genus Bacillus (23%). Antibiotic susceptibility explained the prevalence of resistance in isolates ciprofloxacin (100%), ampicillin (100%), sulfamethoxazole-trimethoprim (85%), tetracycline (75%), amoxicillin (55%), ofloxacin (50%), ceftazidime (45%), amoxicillin/clavulanic acid (45%), levofloxacin (30%), cefpodoxime (25%), cefotaxime (25%), cefotaxime/clavulanic acid (20%), and imipenem (10%). MICs demonstrated that almost 90% isolates were multi-drug resistant (against at least three antibiotics), specially against ciprofloxacin, and tetracycline with the highest resistance levels for Shigella sp. (NCCP-421) (MIC-CIP up to 75 μg mL(-1)) and Escherichia sp. (NCCP-432) (MIC-TET up to 250 μg mL(-1)). PCR-assisted detection of antibiotic resistance genes showed that 54% isolates were positive for bla(TEM) gene, 7% isolates were positive for bla(CTX-M) gene, 23% isolates were positive for each of qnrS and mcr-1 genes, 23% isolates were co-positive in combinations of qnrS and mcr-1 genes and bla(TEM) and mcr-1 genes, whereas none of the isolate showed presence of bla(NDM-1) gene.202134426357
1235110.9981Characterization of integrons and antimicrobial resistance genes in clinical isolates of Gram-negative bacteria from Palestinian hospitals. Sixty Gram-negative bacterial isolates were collected from Palestinian hospitals in 2006. Thirty-two (53.3%) isolates showed multidrug resistance phenotypes. PCR and DNA sequencing were used to characterize integrons and antimicrobial resistance genes. PCR screening showed that 19 (31.7%) and five (8.3%) isolates were positive for class 1 and class 2 integrons, respectively. DNA-sequencing results for the captured antimicrobial resistance gene cassettes within class 1 integrons identified the following genes: dihydrofolate reductases, dfrA1, dfrA5, dfrA7, dfrA12, dfrA17 and dfrA25; aminoglycoside adenyltransferases, aadA1, aadA2, aadA5, aadA12 and aadB; aminoglycoside acetyltransferase, aac(6')-Ib; and chloramphenicol resistance gene, cmlA1. ESBL were identified in 25 (41.7%) isolates. The identified ESBL were bla(CTX-M-15), bla(CTX-M-56), bla(OXA-1), bla(SHV-1), bla(SHV-12), bla(SHV-32) and bla(TEM-1) genes. Moreover, we characterized the plasmid-mediated quinolone resistance genes, aac(6')-Ib-cr and qnrB2, which were detected in seven (11.7%) and two (3.3%) isolates, respectively. In this study various types of antibiotic resistance genes have been identified in Gram-negative bacteria from Palestinian hospitals, many of which are reported in the Middle East area for the first time.200919903259
1168120.9980Dairy Cattle and the Iconic Autochthonous Cattle in Northern Portugal Are Reservoirs of Multidrug-Resistant Escherichia coli. Background/Objectives: Animals destined for human consumption play a key role in potentially transmitting bacteria carrying antibiotic resistance genes. However, there is limited knowledge about the carriage of antibiotic-resistant bacteria in native breeds. We aimed to characterize the phenotypic profiles and antibiotic resistance genes in Escherichia coli isolated from bovines, including three native Portuguese bovine breeds. Methods: Forty-nine E. coli isolates were selected from 640 fecal samples pooled by age group (eight adult or eight calf samples) from each farm, representing both dairy cattle raised in intensive systems and meat cattle raised in extensive systems in Northern Portugal. The presumptive E. coli colonies plated onto MacConkey agar were confirmed using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The antibiotic resistance profiles were screened by antimicrobial susceptibility testing (EUCAST/CLSI guidelines), and the antibiotic resistance genes by PCR. Results: Most isolates showed resistance to ampicillin (69%), tetracycline (57%), gentamicin (55%), and trimethoprim + sulfamethoxazole (53%), with no resistance to imipenem. Resistance to at least one antibiotic was found in 92% of isolates, while 59% exhibited multidrug resistance. Most calf isolates, including those from native breeds, showed a multidrug-resistant phenotype. Among the adults, this was only observed in Holstein-Friesian and Barrosã cattle. None of the Holstein-Friesian isolates were susceptible to all the tested antibiotics. ESBL-producing E. coli was identified in 39% of isolates, including those from Holstein-Friesian calves and adults, Cachena calves and Minhota adults. The sul2 gene was detected in 69% of isolates, followed by bla(CTX-M) (45%), aac(3')-IV (41%), and aac(6')-Ib-cr (31%), with a higher prevalence in adults. Conclusions: This pioneering study highlights the concerning presence of multidrug-resistant E. coli in native Portuguese cattle breeds.202439766598
1313130.9980Molecular epidemiology of ceftiofur-resistant Escherichia coli isolates from dairy calves. Healthy calves (n = 96, 1 to 9 weeks old) from a dairy herd in central Pennsylvania were examined each month over a five-month period for fecal shedding of ceftiofur-resistant gram-negative bacteria. Ceftiofur-resistant Escherichia coli isolates (n = 122) were characterized by antimicrobial resistance (disk diffusion and MIC), serotype, pulsed-field gel electrophoresis subtypes, beta-lactamase genes, and virulence genes. Antibiotic disk diffusion assays showed that the isolates were resistant to ampicillin (100%), ceftiofur (100%), chloramphenicol (94%), florfenicol (93%), gentamicin (89%), spectinomycin (72%), tetracycline (98%), ticarcillin (99%), and ticarcillin-clavulanic acid (99%). All isolates were multidrug resistant and displayed elevated MICs. The E. coli isolates belonged to 42 serotypes, of which O8:H25 was the predominant serotype (49.2%). Pulsed-field gel electrophoresis classified the E. coli isolates into 27 profiles. Cluster analysis showed that 77 isolates (63.1%) belonged to one unique group. The prevalence of pathogenic E. coli was low (8%). A total of 117 ceftiofur-resistant E. coli isolates (96%) possessed the bla(CMY2) gene. Based on phenotypic and genotypic characterization, the ceftiofur-resistant E. coli isolates belonged to 59 clonal types. There was no significant relationship between calf age and clonal type. The findings of this study revealed that healthy dairy calves were rapidly colonized by antibiotic-resistant strains of E. coli shortly after birth. The high prevalence of multidrug-resistant nonpathogenic E. coli in calves could be a significant source of resistance genes to other bacteria that share the same environment.200616751500
1378140.9980Antimicrobial resistance and resistance genes in Escherichia coli strains isolated from commercial fish and seafood. The purpose of this study was to investigate the antimicrobial resistance and to characterize the implicated genes in Escherichia coli isolated from commercial fish and seafood. Fish and seafood samples (n=2663) were collected from wholesale and retail markets in Seoul, Korea between 2005 and 2008. A total of 179 E. coli isolates (6.7%) from those samples were tested for resistance to a range of antimicrobial agents. High rates of resistance to the following drugs were observed: tetracycline (30.7%), streptomycin (12.8%), cephalothin (11.7%), ampicillin (6.7%) and ticarcillin (6.1%). No resistances to amikacin, amoxicillin/clavulanic acid and cefoxitin were observed. Seventy out of 179 isolates which were resistant to one or more drugs were investigated by PCR for the presence of 3 classes of antimicrobial resistance genes (tetracycline, aminoglycosides and beta-lactams), class 1, 2 and 3 integrons. Gene cassettes of classes 1 and 2 integrons were further characterized by amplicon sequencing. The tetracycline resistance genes tetB and tetD were found in 29 (41.4%) isolates and 14 (20%) isolates, respectively. The beta-lactam resistance gene, bla(TEM) was found in 15 (21.4%) isolates. The aminoglycoside resistance gene, aadA was found in 18 (25.7%) isolates. Class 1 integron was detected in 41.4% (n=29) of the isolates, while only 2.9% (n=2) of the isolates were positive for the presence of class 2 integron. Two different gene cassettes arrangements were identified in class 1 integron-positive isolates: dfrA12-aadA2 (1.8 kb, five isolates) and aadB-aadA2 (1.6 kb, four isolates). One isolate containing class 2 integron presented the dfrA1-sat-aadA1 gene cassette array. These data suggest that commercial fish and seafood may act as the reservoir for multi-resistant bacteria and facilitate the dissemination of the resistance genes.201222071288
1323150.9980Detection of antibiotic resistant enterococci and Escherichia coli in free range Iberian Lynx (Lynx pardinus). Thirty fecal samples from wild specimens of Iberian lynx were collected and analyzed for Enterococcus spp. (27 isolates) and Escherichia coli (18 isolates) recovery. The 45 isolates obtained were tested for antimicrobial resistance, molecular mechanisms of resistance, and presence of virulence genes. Among the enterococci, Enterococcus faecium and Enterococcus hirae were the most prevalent species (11 isolates each), followed by Enterococcus faecalis (5 isolates). High percentages of resistance to tetracycline and erythromycin (33% and 30%, respectively) were detected among enterococcal isolates. The tet(M) and/or tet(L), erm(B), aac(6')-Ie-aph(2″)-Ia, ant(6)-Ia, or aph(3')-IIIa genes were detected among resistant enterococci. Virulence genes were detected in one E. faecalis isolate (cpd, cylB, and cylL) and one E. hirae isolate (cylL). High percentages of resistance were detected in E. coli isolates to tetracycline (33%), streptomycin (28%), nalidixic acid (28%), and sulfamethoxazole-trimethoprim (SXT, 22%). Additionally, the blaTEM, tet(A), aadA, cmlA, and different combinations of sul genes were detected among most ampicillin, tetracycline, streptomycin, chloramphenicol and SXT-resistant isolates, respectively. Two isolates contained a class 1 integron with the gene cassette arrays dfrA1 + aadA1 and dfrA12 + aadA2. The E. coli isolates were ascribed to phylo-groups A (n=5); B1 (n=4); B2 (n=6), and D (n=3), with the virulence gene fimA present in all E. coli isolates. This study found resistance genes in wild specimens of Iberian lynx. Thus, it is important to notice that multiresistant bacteria have reached species as rare and completely non-synanthropic as the Iberian lynx. Furthermore, the susceptibility of this endangered species to bacterial infection may be affected by the presence of these virulence and resistance genes.201323588135
1294160.9980Isolation and detection of antibiotics resistance genes of Escherichia coli from broiler farms in Sukabumi, Indonesia. OBJECTIVE: This study aimed to isolate and identify Escherichia coli from broiler samples from Sukabumi, Indonesia. Also, antibiogram studies of the isolated bacteria were carried out considering the detection of the antibiotic resistance genes. MATERIALS AND METHODS: Cloaca swabs (n = 45) were collected from broilers in Sukabumi, Indonesia. Isolation and identification of E. coli were carried out according to standard bacteriological techniques and biochemical tests, followed by confirmation of the polymerase chain reaction targeting the uspA gene. Antibiotic sensitivity test, using several antibiotics [tetracycline (TE), oxytetracycline (OT), ampicillin (AMP), gentamicin (CN), nalidixic acid (NA), ciprofloxacin (CIP), enrofloxacin (ENR), chloramphenicol, and erythromycin] was carried out following the Kirby-Bauer disk diffusion method. Detection of antibiotic resistance coding genes was carried out by PCR using specific oligonucleotide primers. Statistical analysis was carried out with one-way analysis of variance. RESULTS: The results showed that 55.6% (25/45) of the samples were associated with the presence of E. coli. Antibiotic sensitivity test showed that the E. coli isolates were resistant to TE (88%; 22/25), OT (88%; 22/25), AMP (100%; 25/25), CN (64%; 16/25), NA (100%; 22/25), CIP (88%; 22/25), ENR (72%; 18/25), chloramphenicol (0%; 0/25), and erythromycin (92%; 23/25). On the other hand, the antibiotic resistance coding genes were tetA (86.4%; 19/22), blaTEM (100%; 25/25), aac(3)-IV (0%; 0/16), gyrA (100%; 25/25), and ermB (13%; 3/23). It was found that chloramphenicol is markedly different from other antibiotic treatment groups. CONCLUSION: Escherichia coli was successfully isolated from cloacal swabs of broiler in Sukabumi, Indonesia. The bacteria were resistant to TE, OT, AMP, CN, NA, CIP, ENR, and erythromycin. Chloramphenicol was more sensitive and effective than other antibiotics in inhibiting the growth of E. coli. The antibiotic resistance genes detected were tetA, blaTEM, gyrA, and ermB.202133860017
1373170.9980Multidrug resistant Aeromonas spp. isolated from zebrafish (Danio rerio): antibiogram, antimicrobial resistance genes and class 1 integron gene cassettes. Aeromonas spp. are Gram-negative opportunistic bacteria which have been commonly associated with fish diseases. In this study, antibiogram, antimicrobial resistance genes and integrons of 43 zebrafish-borne Aeromonas spp. were studied. The isolates were identified as six Aeromonas species (A. veronii biovar veronii (n = 26), A. veronii biovar sobria (n = 3), A. hydrophila (n = 8), A. caviae (n = 3), A. enteropelogenes (n = 2) and A. dhakensis (n = 1)). Antibiogram of the isolates indicated that most of them were resistant to amoxicillin (100·00%), nalidixic acid (100·00%), oxytetracycline (100·00%), ampicillin (93·02%), tetracycline (74·42%), rifampicin (67·44%) and imipenem (65·15%). Multiple antimicrobial resistance (MAR) index values ranged from 0·19-0·44 to 90·70% isolates showed multidrug resistance. PCR of antimicrobial resistance genes revealed that the tetracycline resistance gene (tetA) was the most predominant (67·44%) among the isolates. The qnrS (53·49%), tetB (30·23%), tetE (30·23%), qnrB (23·26%) and aac(6')-Ib-cr (4·65%) genes were also detected. Class 1 integrase (IntI1) gene was found in 46·51% of the isolates. Two types of class 1 integron gene cassette profiles (qacG-aadA6-qacG and drfA1) were identified. The results showed that zebrafish-borne aeromonads can harbour different types of antimicrobial resistance genes and class 1 integrons. SIGNIFICANCE AND IMPACT OF THE STUDY: Aeromonas spp. are important pathogens found in diverse environments. Antimicrobial resistance genes and integrons of ornamental fish-borne Aeromonas spp. are not well studied. The antibiogram, antimicrobial resistance genes and class 1 integrons of Aeromonas spp. isolated from zebrafish were characterized for the first time in Korea. The prevalence of tetracycline resistance genes, plasmid-mediated quinolone resistance genes and class 1 integron gene cassettes were observed among the isolates. The qacG-aadA6-qacG gene cassette was identified for the first time in Aeromonas spp. The results suggest that the wise use of antimicrobials is necessary for the better management of the ornamental fish.201930790321
1133180.9980High resistance to tetracycline and ciprofloxacin in bacteria isolated from poultry farms in Ibadan, Nigeria. INTRODUCTION: Resistance to ciprofloxacin and tetracycline is increasing in the food chain especially in E. coli strains and more worrisome will be occurrence of extended-spectrum beta-lactamase (ESBL) producers among ciprofloxacin- and tetracycline-resistant isolates. This study was undertaken to investigate the occurrence and mechanism of ciprofloxacin-, tetracycline- and ESBL-resistant bacteria in poultry in Ibadan, Nigeria. METHODOLOGY: Bacteria were isolated from poultry feces in two farms in Ibadan and identified by MALDI-TOF. Antibiotic susceptibility patterns of the isolates were determined by disc diffusion and Minimum Inhibitory Concentration (MIC) using Vitek-2 apparatus. Four tetracycline genes and six plasmids mediated quinolone resistance genes (PMQR) were investigated by PCR. Whole genome sequencing was done for strains that were ESBL producers. RESULTS: Bacterial strains (≥ 105 cfu/mL) were counted on ciprofloxacin and tetracycline supplemented plates. 106 bacteria from 14 different species were identified with high resistance to quinolones, tetracycline and trimethoprim. 49% of the strains were E. coli with 90% resistance for nalidixic acid, moxifloxacin (94%), ciprofloxacin (88%) levofloxacin (78%) and tetracycline (77%). The genes tetA, tetB, qnrB, qnrS and qepA were detected with 37%, 4%, 35%, 4% and 2% prevalence in E. coli respectively. Three ESBL-producing E. coli of the sequence type ST-6359 were found and harboured blaCTX-M-15 located in the chromosome, at the same insertion site. All the ESBL producers harboured mutations in gyrA (S83L/D87N/D678E) and parC (S80I). CONCLUSION: The observed high quinolones and tetracycline resistance with ESBL producers in this study calls for caution in the use of these antibiotics in poultry feeds.201831940298
1307190.9980Identification of shiga toxin and intimin coding genes in Escherichia coli isolates from pigeons (Columba livia) in relation to phylotypes and antibiotic resistance patterns. Shiga toxin-producing Escherichia coli (STEC) strains are responsible for outbreaks of human intestinal diseases worldwide. Pigeons are distributed in public areas and are potential reservoirs for pathogenic bacteria. One hundred fifty-four fresh fecal samples were obtained from trapped pigeons in southeast of Iran and were cultured for isolation of E. coli. The isolates were examined to determine the prevalence of stx1, stx2, and eae genes, antimicrobial resistance, and their phylotypes. The confirmed E. coli isolates (138) belong to four phylogenetic groups: A (54.34%), B1 (34.05%), B2 (3.62%), and D (7.79%). Thirteen (9.42%) isolates were positive for one of the examined genes. Eight isolates (5.79%) were positive for eae, four (2.89%) for stx2, and one isolate (1.44%) for stx1 gene. Phylotyping assays showed that eight eae-positive isolates fall into three phylogroups; A (three isolates), B1 (three isolates), and D (two isolates), whereas four stx2-positive isolates belonged to the A (three isolates) and D (one isolate) groups. The stx1-positive isolate belonged to phylogroup A. One hundred six isolates (76.81%) showed resistance to at least one of the selected antibacterial agents. The maximum resistance rate was against oxytetracycline (73.91%), and the minimum was against flumequine (2.17%). Twenty different patterns of drug resistance were observed. According to the results, pigeons could be considered as carriers of STEC strains. However, E. coli isolates of pigeon feces increase the potential of these birds to act as a reservoir of multiple antibiotic resistant bacteria.201222105907