# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 1236 | 0 | 0.9983 | Molecular 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. | 2011 | 21338385 |
| 1311 | 1 | 0.9981 | Prevalence 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. | 2018 | 29323530 |
| 1313 | 2 | 0.9981 | Molecular 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. | 2006 | 16751500 |
| 1309 | 3 | 0.9981 | Phenotypic 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. | 2007 | 17544234 |
| 1375 | 4 | 0.9980 | Characterization 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. | 2013 | 24135609 |
| 1324 | 5 | 0.9980 | Molecular 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. | 2010 | 20624632 |
| 1235 | 6 | 0.9980 | Characterization 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. | 2009 | 19903259 |
| 1111 | 7 | 0.9980 | Molecular Characterization of Cotrimoxazole Resistance Genes and Their Associated Integrons in Clinical Isolates of Gram-Negative Bacteria from Tanzania. Cotrimoxazole is widely used, particularly as a prophylactic drug in HIV patients. We assessed resistance mechanisms among cotrimoxazole resistant-Gram negative bacterial isolates (n = 123) obtained from blood (n = 69) and urine (n = 54) from Tanzanian patients. sul genes were detected in 98% (121/123) of the isolates. Coexistence of sul1 and sul2 was common (49/123). The dfr genes were found in 63% (77/123) of all isolates. sul1, dfrA15, and dfrA5 genes predominated among Klebsiella pneumoniae, while sul2 and dfrA1 genes were frequent in Escherichia coli isolates. Two isolates, both K. pneumoniae, carried sul3. Integrons were detected in 81.3% (100/123) of all isolates. Class 1 integrons were found in 95% (42/44), 53% (23/43), and 80.6% (25/31) of K. pneumoniae, E. coli, and other Enterobacteriaceae isolates, respectively. Class 2 integrons were found in 14% of E. coli, but not in K. pneumoniae. All sul1 genes in K. pneumoniae were carried in class 1 integrons. Gene cassette arrays dfrA5 and dfrA15-aadA1 were most frequently associated with class 1 integrons, while class 2 integrons contained only dfrA1-sat2-aadA1 gene cassettes. This is the first report of sul3 gene in K. pneumoniae from human sources. The finding that mechanisms differ between E. coli and K. pneumoniae may broaden our understanding of cotrimoxazole resistance. | 2017 | 27533639 |
| 1334 | 8 | 0.9980 | Intimin (eae) and virulence membrane protein pagC genes are associated with biofilm formation and multidrug resistance in Escherichia coli and Salmonella enterica isolates from calves with diarrhea. OBJECTIVES: This study aimed to evaluate the association of the intimin (eae) and pagC genes with biofilm formation and multidrug resistance (MDR) phenotype in Escherichia coli and Salmonella enterica collected from calves with diarrhea. RESULTS: Fecal samples (n: 150) were collected from calves with diarrhea. Of 150 fecal samples, 122 (81.3%) were culture positive and 115/122 (94.2%) were Gram-negative bacteria. Among them, E. coli (n = 64/115, 55.6%) was the most common isolate followed by S. enterica (n = 41/115, 35.6%). Also, 10 (8.6%) isolates were other Enterobacteriaceae bacteria including Klebsiella and Proteus species. Eighty-nine isolates (77.4%) from calf diarrhea, including 52 (81.3%) E. coli and 37 (90.2%) S. enterica were MDR. The eae and pagC genes were detected in 33 (51.5%) E. coli and 28 (68.3%) S. enterica isolates, respectively. There was a strong association between these genes and biofilm formation and MDR phenotype (P-value = 0.000). All E. coli isolates carrying the eae gene were biofilm producers and MDR. Also, all pagC-positive S. enterica isolates were MDR and 25 (89.3%) isolates of them produced biofilm. | 2022 | 36221149 |
| 1170 | 9 | 0.9980 | Mechanisms 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. | 2002 | 12523629 |
| 1310 | 10 | 0.9980 | Antimicrobial 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. | 2016 | 27296596 |
| 1112 | 11 | 0.9980 | Molecular Analysis of Antimicrobial Resistance among Enterobacteriaceae Isolated from Diarrhoeic Calves in Egypt. The present study was designed to investigate the presence of genes that conferred resistance to antimicrobials among Enterobacteriaceae that were isolated from diarrhoeic calves. A total of 120 faecal samples were collected from diarrhoeic calves that were raised in Kafr El-Sheikh governorate, Egypt. The samples were screened for Enterobacteriaceae. A total of 149 isolates of bacteria were recovered and identified; Escherichia coli was found to be the most overwhelming species, followed by Citrobacter diversus, Shigella spp., Serratia spp., Providencia spp., Enterobacter spp., Klebsiella pneumoniae, Proteus spp., Klebsiella oxytoca, and Morganella morganii. All isolates were tested for susceptibility to 12 antimicrobials; resistant and intermediately resistant strains were screened by conventional polymerase chain reaction for the presence of antimicrobial resistance genes. Of the 149 isolates, 37 (24.8%) exhibited multidrug resistant phenotypes. The most prevalent multidrug resistant species were E. coli, C. diversus, Serratia spp., K. pneumoniae, Shigella spp., Providencia spp., and K. oxytoca. Class 1 integrons were detected in 28 (18.8%) isolates. All isolates were negative for class 2 integrons. The bla(TEM) gene was identified in 37 (24.8%) isolates, whereas no isolates carried the bla(CTX-M) gene(.) The florfenicol gene (floR) was detected in two bacterial isolates (1.3%). The findings of this study reveal that calves may act as potential reservoirs of multidrug resistant bacteria that can be easily transmitted to humans. | 2021 | 34201226 |
| 1308 | 12 | 0.9980 | Antimicrobial resistance genes and virulence gene encoding intimin in Escherichia coli and Enterococcus isolated from wild rabbits (Oryctolagus cuniculus) in Tunisia. The spread of antimicrobial-resistant bacteria in wildlife must be viewed as a major concern with serious implications for human and animal health. Escherichia coli and enterococcal isolates were recovered from faecal samples of 49 wild rabbits (Oryctolagus cuniculus) on specific media and were characterised using biochemical and molecular tests. For all isolates, antimicrobial susceptibility testing was performed, and resistance genes were detected by PCR. Molecular typing of isolates was carried out by pulsed-field gel-electrophoresis, and E. coli strains were also tested for the presence of intimin (eae) gene characteristic of rabbit enteropathogenic E. coli. A total of 34 E. coli and 36 enterococci [E. hirae (52.8%) and E. faecalis (47.2%)] were obtained. For E. coli, resistance to tetracycline (94%), streptomycin (62%), ciprofloxacin (47%), trimethoprim-sulphamethoxazole (35%) and chloramphenicol (6%) was observed. Resistance to third-generation cephalosporins was detected in one E. coli strain that carried the bla(CMY-2) and bla(TEM-1) genes. Class 1 integrons were detected in eight isolates. For enterococci, resistance to tetracycline (63.9%), erythromycin (30.5%), streptomycin (18.2%), and chloramphenicol (5.5%) was detected. The tet(M)+tet(L), erm(B) and ant (6)-Ia genes were identified in thirteen, seven and three resistant Enterococcus strains, respectively. Molecular typing showed a high diversity among our strains. Wild rabbits could represent a reservoir of E. coli, and enterococci carrying antimicrobial resistance genes and E. coli additionally carrying the eae gene of enteropathogenic pathotypes could both contaminate the environment. our finding seems to represent the first report of eae-positive E. coli in wild rabbits. | 2019 | 31842593 |
| 1227 | 13 | 0.9980 | Antibiotic resistance among coliform bacteria isolated from carcasses of commercially slaughtered chickens. A total of 322 coliform bacteria Escherichia coli, Enterobacter spp., Citrobacter spp., Klebsiella spp. and Serratia spp., were isolated from 50 carcasses of commercially slaughtered chickens. Their resistance to ampicillin, tetracycline, gentamicin, chloramphenicol, cephalotine, cotrimoxazole, nalidixic acid and nitrofurantoin, were determined. The most commonly found resistance was to tetracycline followed by cephalotine, cotrimoxazole and nalidixic acid. A large percentage of E. coli (41%) and Klebsiella spp. (38%) showed multiple antibiotic resistance. | 1990 | 2282290 |
| 1114 | 14 | 0.9980 | Third-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. | 2021 | 34943649 |
| 1364 | 15 | 0.9979 | Antimicrobial resistance patterns of Shiga toxin-producing Escherichia coli O157:H7 and O157:H7- from different origins. Shiga toxin-producing Escherichia coli (STEC) serotypes including O157:H7 (n = 129) from dairy cows, cull dairy cow feces, cider, salami, human feces, ground beef, bulk tank milk, bovine feces, and lettuce; and O157:H7- (n = 24) isolated from bovine dairy and bovine feedlot cows were evaluated for antimicrobial resistance against 26 antimicrobials and the presence of antimicrobial resistance genes (tetA, tetB, tetC, tetD, tetE, tetG, floR, cmlA, strA, strB, sulI, sulII, and ampC). All E. coli exhibited resistance to five or more antimicrobial agents, and the majority of isolates carried one or more target antimicrobial resistance gene(s) in different combinations. The majority of E. coli showed resistance to ampicillin, aztreonam, cefaclor, cephalothin, cinoxacin, and nalidixic acid, and all isolates were susceptible to chloramphenicol and florfenicol. Many STEC O157:H7 and O157:H7-isolates were susceptible to amikacin, carbenicillin, ceftriaxone, cefuroxime, ciprofloxacin, fosfomycin, moxalactam, norfloxacin, streptomycin, tobramycin, trimethoprim, and tetracycline. The majority of STEC O157:H7 (79.8%) and O157:H7- (91.7%) carried one or more antimicrobial resistance gene(s) regardless of whether phenotypically resistant or susceptible. Four tetracycline resistant STEC O157:H7 isolates carried both tetA and tetC. Other tetracycline resistance genes (tetB, tetD, tetE, and tetG) were not detected in any of the isolates. Among nine streptomycin resistant STEC O157:H7 isolates, eight carried strA-strB along with aadA, whereas the other isolate carried aadA alone. However, the majority of tetracycline and streptomycin susceptible STEC isolates also carried tetA and aadA genes, respectively. Most ampicillin resistant E. coli of both serotypes carried ampC genes. Among sulfonamide resistance genes, sulII was detected only in STEC O157:H7 (4 of 80 sulfonamide-resistant isolates) and sulI was detected in O157:H7- (1 of 16 sulfonamide resistant isolates). The emergence and dissemination of multidrug resistance in STEC can serve as a reservoir for different antimicrobial resistance genes. Dissemination of antimicrobial resistance genes to commensal and pathogenic bacteria could occur through any one of the horizontal gene transfer mechanisms adopted by the bacteria. | 2007 | 17536933 |
| 1095 | 16 | 0.9979 | Short communication: Extended-spectrum cephalosporin-resistant Escherichia coli in colostrum from New Brunswick, Canada, dairy cows harbor bla(CMY-2) and bla(TEM) resistance genes. Dairy calves are colonized shortly after birth by multidrug resistant (MDR) bacteria, including Escherichia coli. The role of dairy colostrum fed to calves as a potential source of MDR bacteria resistance genes has not been investigated. This study determined the recovery rate of extended-spectrum cephalosporin-resistant (ESC-R) E. coli in colostrum from cows. The ESC-R E. coli isolates were further investigated to determine their phenotypic antimicrobial resistance pattern and the genes conferring ESC-R. Fresh colostrum was collected from 452 cows from 8 dairy herds in New Brunswick, Canada. The ESC-R E. coli was isolated from the colostrum by using the VACC agar, a selective media for extended-spectrum β-lactamase producing Enterobacteriaceae. Minimum inhibitory concentration was determined for all the suspected ESC-R E. coli isolates using a commercial gram-negative broth microdilution method. Two multiplex PCR were conducted on all the suspected ESC-R E. coli isolates to determine the presence of the bla(CTX-M) (groups 1, 2, 9, and 8/25) bla(CMY-2), bla(SHV), and bla(TEM) resistance genes. The ESC-R E. coli were detected in 20 (4.43%) of the colostrum samples. At least 1 ESC-R E. coli isolate was detected in 6 (75%) of the dairy herds. All ESC-R E. coli had MDR profiles based on minimum inhibitory concentration testing. No bla(CTX-M) groups genes were detected; however, the bla(CMY-2) gene was detected in 9 or 20 (45%) and bla(TEM) was detected in 7 of 20 (35%) of the ESC-R E. coli. No ESC-R E. coli had both bla(CMY-2) and bla(TEM) resistance genes. This is the first report of bla(CMY-2) and bla(TEM) genes found in E. coli isolates cultured from dairy colostrum to our knowledge. | 2017 | 28780105 |
| 1116 | 17 | 0.9979 | Detection of blaCTX-M genes in ESBL-producing Klebsiella isolates from animals in Croatia. This study investigated the frequency of third-generation cephalosporin resistance in Klebsiella spp. isolated from animals in Croatia and the presence of blaCTX-M genes. A total of 711 enteric bacteria were isolated from clinical samples, and Klebsiella spp. isolates accounted for 6.9% (n = 49). Thirteen Klebsiella isolates (26.5%) were ESBL producers, nine isolates from the Klebsiella pneumoniae species complex (69.2%), and four (30.8%) Klebsiella oxytoca isolates. All carried the blaCTX-M-15 gene, and antimicrobial susceptibility testing revealed them as multidrug resistant. All were resistant to all tested cephalosporins, fluoroquinolones, aminoglycosides and aztreonam, 92.3% showed resistance to tetracycline, 84.6% to trimethoprim-sulfamethoxazole and 69.2% to nitrofurantoin. No isolate showed resistance to imipenem and meropenem. It can be concluded that ESBL-producing Klebsiella expressing the blaCTX-M gene are not rare among Klebsiella isolates from animals in Croatia. | 2023 | 37027245 |
| 1094 | 18 | 0.9979 | Detection of plasmid-mediated quinolone resistance genes in β-lactamase-producing Escherichia coli isolates from layer hens. This study was conducted to investigate the presence of plasmid-mediated quinolone resistance (PMQR) genes in β-lactamase-producing Escherichia coli isolates from layer hens and to characterize their molecular background. Among 142 E. coli isolates, 86 (60.6%) showed multidrug resistance and 15 (10.6%) were found to be β-lactamase-producing E. coli. Extended-spectrum β-lactamase (ESBL) and plasmid-mediated AmpC (pAmpC) β-lactamase genes, blaCTX-M-14 and blaCMY-2, were identified in three and six E. coli isolates, respectively. The non-ESBL or pAmpC gene, blaTEM-1, was found in eight of the isolates. Two isolates had both genes, blaCTX-M-14 and blaTEM-1. Among the 15 β-lactamase-producing E. coli, six PMQR genes, qnrS1 (n = 3) and qnrB4 (n = 3), were identified. Among the six PMQR-positive E. coli isolates, four exhibited double amino acid exchanges at both gyrA and parC with ciprofloxacin and enrofloxacin minimum inhibitory concentrations of ≥32 and ≥16 μg/mL, respectively. Additionally, five transconjugants (33.3%) showed a transferability of β-lactamase and PMQR genes. Pulsed-field gel electrophoresis (PFGE) analysis was conducted to investigate the 15 β-lactamase-producing E. coli isolates. In PFGE, E. coli included three PFGE patterns showing the same farms and in accordance with both β-lactamase and PMQR genes and the antimicrobial resistance pattern. Layer hens may act as a reservoir of antibiotic-resistant bacteria, and the PMQR gene in β-lactamase-producing E. coli isolates from layer hens has the potential to enter the food chain. Therefore, our findings suggest that comprehensive surveillance of antimicrobial use in laying operation systems is necessary. | 2019 | 30496543 |
| 1088 | 19 | 0.9979 | Detection and Molecular Characterization of Escherichia coli Strains Producers of Extended-Spectrum and CMY-2 Type Beta-Lactamases, Isolated from Turtles in Mexico. Multidrug-resistant bacteria are a growing problem in different environments and hosts, but scarce information exists about their prevalence in reptiles. The aim of this study was to analyze the resistance mechanisms, molecular typing, and plasmid content of cefotaxime-resistant (CTX(R)) Escherichia coli isolates recovered from cloacal samples of 71 turtles sheltered in a herpetarium in Mexico. CTX(R)-E. coli were recovered in 11 of 71 samples (15.5%), and one isolate/sample was characterized. Extended-spectrum β-lactamase (ESBL)-producing E. coli isolates were detected in four samples (5.6%): two strains carried the blaCTX-M-2 gene (phylogroup D and ST2732) and two contained the blaCTX-M-15 gene (phylogroup B1 and lineages ST58 and ST156). The blaCMY-2 gene was detected by PCR in E. coli isolates of eight samples (9.8%) (one of them also carried blaCTX-M-2); these isolates were distributed into phylogroups A (n = 1), B1 (n = 6), and D (n = 1) and typed as ST155, ST156, ST2329, and ST2732. Plasmid-mediated quinolone resistance (PMQR) genes were detected in five isolates [aac(6')Ib-cr, qnrA, qnrB19, and oqxB]. From three to five replicon plasmids were detected among the strains, being IncFIB, IncI1, IncFrep, and IncK the most prevalent. ESBL or pAmpC genes were transferred by conjugation in four strains, and the blaCTX-M-15 and blaCMY-2 genes were localized in IncFIB or IncI1 plasmids by Southern blot hybridization assays. Class 1 and/or class 2 integrons were detected in eight strains with six different structures of gene cassette arrays. Nine pulsed-field gel electrophoresis patterns were found among the 11 studied strains. To our knowledge, this is the first detection of ESBL, CMY-2, PMQR, and mobile determinants of antimicrobial resistance in E. coli of turtle origin, highlighting the potential dissemination of multidrug-resistant bacteria from these animals to other environments and hosts, including humans. | 2016 | 27482752 |