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1.
The emergence of NDM‐producing Escherichia coli has considerably threatened human and animal health worldwide. This study describes for the first time in Egypt, the draft genome sequences of emerging NDM‐5‐producing E. coli from humans and dogs, and investigates genetic relatedness between isolates from both sources. Two E. coli from human urine and seven from environmental clinical samples of dogs exhibited resistance to carbapenems and harbouring blaNDM were subjected to Illumina Miseq whole‐genome sequencing (WGS). Assembly and analysis of the reads were performed to identify resistance genes, multilocus sequence types (MLST), plasmid replicon types (Inc) and insertion sequences (IS) of the blaNDM region; core genome MLST (cgMLST) analysis was also performed. Two different NDM alleles were identified; blaNDM‐5 in E. coli HR119 from the urine of a healthy person and environmental samples of dogs, and blaNDM‐1 in E. coli HR135 from a human patient's urine. Multiple mobilizable resistance genes to different antimicrobial classes were identified except the colistin resistance gene, mcr. E. coli isolates from humans and dogs were assigned to different sequence types (STs). Using cgMLST, dog isolates clustered together with only 1–2 allellic differences; however, human E. coli showed 1,978 different allelles compared with dog isolates. Plasmidfinder results indicated the presence of an IncX3 replicon in blaNDM‐5‐producing E. coli; however, blaNDM‐1 was linked to IncCoIKP3. Notably, the NDM region (3 Kb) in all isolates from humans and dogs was highly similar with variable flanking sequences that represented different IS elements. This study reports the first emergence of NDM‐5‐producing E. coli from dogs in Egypt that shared some genetic features with human isolates and could be considered potential public health threats.  相似文献   

2.
ESBL/AmpC‐producing Escherichia coli is increasingly isolated from humans and animals worldwide. The occurrence of ESBL/AmpC‐producing E. coli was studied in food‐producing animals in Finland, a country with a low and controlled use of antimicrobials in meat production chain. A total of 648 cattle, 531 pig, 495 broiler and 35 turkey faecal samples were collected from four Finnish slaughterhouses to determine the presence of extended‐spectrum β‐lactamase (ESBL/AmpC)‐producing E. coli. In addition, 260 broiler and 15 turkey samples were screened for carbapenemase‐producing E. coli. Susceptibility to different class of cephalosporins and meropenem was determined with disc diffusion tests according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Determination of ESBL/AmpC production was performed with a combination disc diffusion test according to the recommendations of the European Food Safety Authority (EFSA). Plasmidic blaESBL/AmpC genes were characterized by polymerase chain reaction and sequencing. A collection of isolates producing AmpC enzyme but not carrying plasmidic blaAmpC was analysed by PCR and sequencing for possible chromosomal ampC promoter area mutations. Altogether ESBL/AmpC‐producing E. coli was recovered from five cattle (0.8%), eight pig (1.5%) and 40 broiler samples (8.1%). No ESBL/AmpC‐producing E. coli was found in turkey samples. Carbapenem resistance was not detected. Altogether ESBL/AmpC‐producing E. coli was found on 4 (2.0%), 3 (4.5%) and 14 (25%) cattle, pig and broiler farms, respectively. From cattle samples 3 (27%) blaCTX‐M‐1 and from broiler samples 13 (33%) blaCTX‐M‐1 and 22 (55%) blaCMY‐2 gene‐carrying isolates were detected. In pigs, no plasmidic blaESBL/AmpC gene‐carrying isolates were found. In all analysed isolates, the same mutations in the promoter region of chromosomal ampC were detected. The results showed low occurrence of ESBL/AmpC‐producing E. coli in Finnish food‐producing animals. In pigs, plasmidic blaESBL/AmpC‐carrying E. coli was not detected at all.  相似文献   

3.
Seventy-six faecal samples were obtained from broilers at slaughterhouse level in Portugal. Samples were inoculated on cefotaxime-supplemented Levine agar plates. Cefotaxime-resistant Escherichia coli isolates were recovered from 32 samples (42.1%), obtaining a total of 34 E. coli isolates (one or two isolates per sample). Susceptibility to 16 antibiotics was studied by disk diffusion method, and 85% of the isolates presented a phenotype of multi-resistance that included antimicrobial agents of at least four different families. Extended-spectrum-beta-lactamases (ESBL) of the TEM and CTX-M groups were detected in 31 ESBL-positive E. coli isolates. Twenty-six isolates harboured the blaTEM-52 gene and two of them also harboured blaTEM-1b. The blaCTX-M-14 gene was identified in three isolates (in association with blaTEM-1b in one of them), and blaCTX-M-32 was demonstrated in two additional isolates. Three of the 34 cefotaxime-resistant isolates (9%) did not produce ESBLs, and two of them presented mutations at positions −42 (C → T), −18 (G → A), −1 (C → T), and +58(C → T) of the promoter/attenuator region of ampC gene. tet(A) and/or tet(B) genes were detected in all 34 tetracycline-resistant isolates, aadA in all 26 streptomycin-resistant isolates; cmlA in 3 of 6 chloramphenicol-resistant isolates, and aac(3)-II or aac(3)-I + aac(3)-IV genes in all 4 gentamicin-resistant isolates. Different combinations of sul1, sul2 and sul3 genes were demonstrated among the 22 trimethoprim–sulfamethoxazole-resistant isolates. Amino acid changes in GyrA and ParC proteins were identified in all 18 ciprofloxacin-resistant isolates. The results of this study indicate that the intestinal tract of healthy poultry is a reservoir of ESBL-positive E. coli isolates.  相似文献   

4.
牛肉源大肠杆菌的耐药性检测及相关耐药基因分布   总被引：6，自引：3，他引：3  
为了解牛肉源大肠杆菌的耐药性并检测其相关耐药基因分布,本研究选取了117株牛肉源大肠杆菌,经药敏纸片法对11种抗菌药物进行了药敏检测,并根据耐药表型利用普通和(或)多重PCR技术对耐四环素菌中tet(A)、tet(B)和tet(C)基因,耐氨苄西林菌中blaTEM1、blaPSE1和blaOXA1基因,耐链霉素菌中strA-strB、aadA1基因,耐磺胺类药菌中sul1、sul2和sul3基因进行了调查分析。结果显示,117株大肠杆菌对四环素、氨苄西林、链霉素和磺胺异恶唑的耐药率较高,分别为89%、42%、38%和22%。tet(A)基因是所有四环素耐药基因中最为流行的一种基因(55%);在检测的3个β-内酰胺类药物耐药基因中,最流行的为blaTEM1基因(73%);链霉素的耐药性主要由strA-strB基因(38%)编码;sul2基因在耐磺胺异恶唑菌中的检出率最高(77%)。结果表明本次分离的牛肉源大肠杆菌耐药非常严重,进一步肯定了肉牛业生产中抗菌药的使用对大肠杆菌耐药性的产生和发展所发挥的重要作用,提示食品动物养殖应严格控制饲料中抗菌药的滥用。  相似文献   

5.
World-wide, enterotoxigenic Escherichia coli (ETEC) and verotoxigenic E. coli (VTEC)-induced diarrhea are economically important for porcine producers. Our aim was to investigate the prevalence of toxin and fimbrial genes among E. coli isolated from diarrheic piglets from randomly selected piggeries in Zimbabwe.We used multiplex PCR for screening STa, STb, LT, and Stx-2e toxins. Subsequently F4, F5, F6, F18 and F41 fimbriae genes were screened in toxin positive isolates. Toxin positive strains lacking tested fimbriae genes were characterized using transmission electron microscopy, agglutination and agglutination inhibition tests. Approximately 32% of the 1,984 isolates tested positive for STa, STb, LT or Stx-2e genes. Of these, approximately 81% had F4, F5, F6, F18 or F41 fimbriae genes. The remaining toxin positive strains lacked tested fimbriae genes and appeared to either express F1-like fimbriae, or lacked fimbriae. The data constitute an important framework for implementation of prevention measures, such as using relevant fimbriae-based vaccines against ETEC induced diarrhea or VTEC-induced edema.  相似文献   

6.
Of 273 samples (rectal swab) collected from free-ranging yaks of Tawang district, Arunachal Pradesh, 42 Shiga toxin-producing Escherichia coli (STEC), six enteropathogenic E. coli (EPEC) and 27 enterotoxigenic E. coli (ETEC) strains were isolated. All the STEC and EPEC strains were further investigated for respective stx variants (for STEC only) and additional putative virulence factors. The 27 ETEC strains were also screened for characteristic enterotoxin gene(s) and colonization factors. Occurrence of ETEC was significantly (p < 0.05) higher in the diarrheic yaks and yaks of less than 1 year of age. Majority of enterovirulent E. coli isolates were resistant to amikacin, azithromycin, chloramphenicol, colistin, doxycycline, furazolidone, nalidixic acid, nitrofurantoin, streptomycin and tetracycline. Dendrogram, constructed with molecular fingerprinting profiles obtained from RAPD (Randomly Amplified Polymorphic DNA) and ERIC (Enterobacterial Repetitive Intergenic Consensus) PCR, placed the isolates in different clusters irrespective of their serotypes, virulence gene and drug resistance pattern. Collectively, the study indicates that yaks, being a potential reservoir of multidrug resistant STEC and EPEC, may represent significant risk to public health in this region. Higher recovery of ETEC isolates from yaks with diarrhea points out that ETEC may be a major determinant for repeated occurrence of diarrhea in yaks.  相似文献   

7.
The emergence and spread of antimicrobial‐resistant (AMR) bacteria in natural environments is a major concern with serious implications for human and animal health. The aim of this study was to determine the prevalence of AMR Escherichia coli (E. coli) in wild birds and mammalian species. Thirty faecal samples were collected from each of the following wildlife species: herring gulls (Larus argentatus), black‐headed gulls (Larus ridibundus), lesser black‐back gulls (Larus fuscus), hybrid deer species (Cervus elaphus x Cervus nippon) and twenty‐six from starlings (Sturnus vulgaris). A total of 115 E. coli isolates were isolated from 81 of 146 samples. Confirmed E. coli isolates were tested for their susceptibility to seven antimicrobial agents by disc diffusion. In total, 5.4% (8/146) of samples exhibited multidrug‐resistant phenotypes. The phylogenetic group and AMR‐encoding genes of all multidrug resistance isolates were determined by PCR. Tetracycline‐, ampicillin‐ and streptomycin‐resistant isolates were the most common resistant phenotypes. The following genes were identified in E. coli: blaTEM, strA, tet(A) and tet(B). Plasmids were identified in all samples that exhibited multidrug‐resistant phenotypes. This study indicates that wild birds and mammals may function as important host reservoirs and potential vectors for the spread of resistant bacteria and genetic determinants of AMR.  相似文献   

8.
In order to estimate the prevalence of AmpC‐ and ESBL β‐lactamase‐producing Enterobacteriaceae in the faecal flora of a healthy domestic canine population, faecal samples were obtained from healthy dogs receiving routine parasitology screening at the Ohio State University Veterinary Medical Center, between January 2013 and April 2013. Samples were screened for the presence of AmpC and ESBL β‐lactamase phenotypes, and the clinically important genotypes, blaCMY and blaCTX‐M, were confirmed via conventional PCR. Minimum inhibitory concentrations were determined for isolates and plasmids were characterized. Two hundred and twelve canine faecal samples were screened, of which 30 harboured isolates carrying the AmpC blaCMY, representing 14.2% of the population (95% CI: 9.4–18.9%). Nine samples harboured isolates that carried the ESBL blaCTX‐M, representing 4.2% of the population (95% CI: 1.5–7.0%). Isolates containing blaCMY harboured multiple plasmid replicon types, while isolates containing blaCTX‐M harboured few plasmid replicon types. Our results suggest that domestic dogs may serve as a reservoir for extended‐spectrum cephalosporin resistance genes for other domestic animal populations as well as for their human companions. This represents a potential veterinary and public health risk that warrants further investigation and continued surveillance to ascertain the nature and extent of the risk. The high level of diversity of plasmid content among isolates harbouring blaCMY suggests broader dissemination relative to blaCTX‐M isolates.  相似文献   

9.
Antibiotic resistance and ESBL constitute a risk to human and animal health. Birds residing close to humans could mirror the spectrum of human associated antibiotic resistance. Household pigeons were screened in Bangladesh to shed light on human associated, as well as, environmental antibiotic resistance. Escherichia coli from pigeons (n = 150) were tested against 11 antibiotics. 89% E. coli isolates were resistant to one or more critically important human antibiotics like ampicillin, cefadroxil, mecillinam, ciprofloxacin, gentamicin and tigecycline. No carbapenamase-producers were detected and the lower ESBL prevalence (5%) in pigeons. ESBL-producing E. coli isolates had blaCTX-M-15 genes. Pigeons shared some bacterial clones and had bird associated sequence types like E. coli ST1408. Fecal carriage of bacteria resistance of critically important human antibiotics, together with examples of shared genotypes among pigeons, indicate the human-birds and bird to bird transmissions are important in the epidemiology of antibiotic resistance.  相似文献   

10.
A PCR based method was developed for the identification of ceftiofur resistance genes (blaCMY-2, blaTEM-1, and ampC) in swine bacterial pathogens. Using this method, the ceftiofur resistant (n = 76) and susceptible (n = 45) strains of Bordetella bronchiseptica, Salmonella spp., Escherichia coli, and Pasteurella multocida were screened for the presence of these three genes. The resistant genes were detected in 70% (blaTEM-1), 68% (blaCMY-2) and 45% (ampC) of the resistant isolates and in 18% (blaTEM-1), 27% (blaCMY-2), and 36% (ampC) of the susceptible isolates. Results obtained in the present study showed widespread distribution of these three resistance genes in ceftiofur-resistant swine pathogens. It was also observed that more pathogens are acquiring these resistance genes.  相似文献   

11.
A total of 52 Escherichia coli strains isolated from diarrhoeic rabbits were investigated for their enteropathogenic E. coli (EPEC) pathotype by PCR amplification of eae and bfp virulence genes. A total of 22 EPEC isolates were identified, serotyped and studied for antibiotic resistance and screened for the detection of extended‐spectrum β‐lactamases (ESBLs). The EPEC isolates belonged to three serogroups (O26, O92 and O103). The most common serogroup (O103:K‐:H2) was observed among 17 EPEC strains, the O92:K‐serogroup in three isolates (the antibiotic sensitive ones) and the remaining O26:K‐serogroup in two isolates (the ESBLs isolates). Resistances to ampicillin and tetracycline were the most frequent and detected followed by resistance to nalidixic acid, streptomycin, trimethoprim–sulphamethoxazole, cefoxitin, gentamicin and ciprofloxacin. All the isolates were sensitive for amikacin, ceftazidime, aztreonam, imipenem, chloramphenicol, tobramycin and amoxicillin + clavulanic acid. Two isolates recovered from two adult animals showed an intermediate susceptibility to cefotaxime, and a positive screening test for ESBL was demonstrated in both. The blaTEM gene was demonstrated in the majority of ampicillin‐resistant isolates. The aac(3)‐II or aac(3)‐IV genes were detected in the four gentamicin‐resistant isolates. In addition, the aadA gene was detected in 60% of streptomycin‐resistant isolates. The tet(A) or tet(B) genes were identified in all tetracycline‐resistant isolates. A total of nine EPEC isolates showed the phenotype SXT‐resistant, and the sul1 and/or sul2 and/or sul3 genes were detected in all of them. Our findings showed that the molecular detection by the eae and bfp genes by PCR followed by serotyping is useful for monitoring trends in EPEC infections of rabbits allowing the identification of their possible reservoirs. The detection of genes involved in the resistance to antibiotics of different families in a relatively high proportion of faecal E. coli isolates of rabbits is of great interest and could be considered a serious public health problem.  相似文献   

12.
The genus Campylobacter comprises members known to be a leading cause of foodborne gastrointestinal illness worldwide. A study was conducted to determine the epidemiology and antimicrobial resistance of Campylobacter in humans in Morogoro, Eastern Tanzania. Isolation of Campylobacter from stool specimens adopted the Cape Town protocol. Campylobacter isolates were preliminarily identified by conventional phenotypic tests and subsequently confirmed by matrix‐assisted laser desorption/ionization–time‐of‐flight (MALDI‐TOF) mass spectrometry and polymerase chain reaction. Antimicrobial resistance testing employed the disc diffusion method. A small proportion of the test isolates was also subjected to agar dilution method. Risk factors for human illness were determined in an unmatched case–control study. Thermophilic Campylobacter were isolated from 11.4% of the screened individuals (n = 1195). The agreement between PCR and MALDI‐TOF was perfect (κ = 1.0). Symptomatics and young individuals were infected with higher numbers than asymptomatic and adults, respectively. The majority (84.6%) of the isolates were C. jejuni and the remaining were C. coli. Isolates had highest resistance (95.6%) for colistin sulphate and lowest for ciprofloxacin (22.1%). The rates of resistance for other antibiotics (azithromycin, erythromycin, tetracycline, cephalothin, gentamycin, nalidixic acid, ampicillin, amoxycillin, norfloxacin, chloramphenicol) ranged from 44.1% to 89%. Comparison between disc diffusion and agar dilution methods indicated a good correlation, and the tests were in agreement to each other (κ ≥ 0.75). Human illness was found to be associated with young age and consumption of chicken meat and pre‐prepared salad. Our data indicate the presence of antibiotic‐resistant thermophilic Campylobacter in humans in the study area. There is a need for routine investigation of the presence of the organisms in gastroenteritis aetiology, including determination of their antibiotic susceptibilities.  相似文献   

13.

This study investigated the occurrence of antimicrobial-resistant Escherichia coli in dairy calves in southern Vietnam. Fecal samples were taken directly from the rectum of 84 calves from 41 smallholder dairy farms, when newborn and at 14 days of age for isolation of E. coli. Escherichia coli strains were isolated from 144 of the 168 fecal samples tested. Of the 144 E. coli isolates, 40% were found to be susceptible to all 12 antimicrobial drugs tested and 53% of the E. coli isolates were resistant to at least three antimicrobials. Calves were colonized with antimicrobial-resistant E. coli already on the day of birth. Resistance to tetracycline was most common, followed by resistance to sulfamethoxazole, ampicillin, trimethoprim, and ciprofloxacin. Four isolates carried a gene encoding for extended-spectrum cephalosporinases (ESC), and these genes belonged to blaCTX-M group 1 (2 isolates), blaCTX-M group 9 (1 isolate), and blaCMY-2 (1 isolate). Thirty-three isolates had a plasmid-mediated quinolone resistance (PMQR) phenotype, and 30 of these carried the qnrS gene. These results are of importance for management routines of dairy cattle to prevent the spread of antimicrobial resistance.

  相似文献   

14.
The dissemination of Enterobacteriaceae expressing resistance to extended‐spectrum cephalosporins, which are therapeutically used in both human and veterinary medicine, is of critical concern. The normal commensal flora of food animals may serve as an important reservoir for the zoonotic food‐borne transmission of Enterobacteriaceae harbouring β‐lactam resistance. We hypothesized that the predominant AmpC and ESBL genes reported in US livestock and fresh retail meat products, blaCMY‐2 and blaCTX‐M, would also be predominant in human enteric flora. We recovered enteric flora from a convenience sample of patients included in a large tertiary medical centre's Clostridium difficile surveillance programme to screen for and estimate the frequency of carriage of AmpC and ESBL resistance genes. In‐ and outpatient diarrhoeic submissions (n = 692) received for C. difficile testing at the medical centre's clinical diagnostic laboratory from July to December, 2013, were included. Aliquoted to a transport swab, each submission was inoculated to MacConkey broth with cefotaxime, incubated at 37°C and then inoculated to MacConkey agars supplemented with cefoxitin and cefepime to select for the AmpC and ESBL phenotypes, with blaCMY and blaCTX‐M genotypes confirmed by PCR and sequencing. From the 692 diarrhoeic submissions, our selective culture yielded 184 isolates (26.6%) with reduced susceptibility to cefotaxime. Of these, 46 (6.7%) samples harboured commensal isolates carrying the AmpC blaCMY. Another 21 (3.0%) samples produced isolates harbouring the ESBL blaCTX‐M: 19 carrying CTX‐M‐15 and 2 with CTX‐M‐27. Our results indicate that β‐lactam resistance genes likely acquired through zoonotic food‐borne transmission are present in the enteric flora of this hospital‐associated population at lower levels than reported in livestock and fresh food products.  相似文献   

15.
The aims of this study were to investigate the prevalence, antibiotic resistance, presence of class 1 and 2 integrons, Extended Spectrum β-Lactamases (ESBL) genes, phylogenetic group and epidemiological relationships of EPEC, ETEC and EHEC pathotypes isolated from patients with diarrhea and farm animals in south east region of Iran. A total of 671 diarrheagenic E. coli (DEC) were collected from stool samples of 395 patients with diarrhea and 276 farm cattles and goats. Presence of EPEC, ETEC and EHEC were identified using multiplex-PCR employing primers targeted the shiga toxin (stx), intimin (eae), bundle forming pili (bfp), and enterotoxins (lt and st) genes. The highest proportion of the patients (64%) were children under age 1–15 year (p ≤ 0.05). Among the isolates, atypical EPEC was detected in 26 patients and 14 animal stool samples, while typical EPEC was found in 2 cattles. ETEC isolates were detected in stools of 13 patients and 4 EHEC was identified in 3 goats and one cattle. The isolates were checked for susceptibility to 14 antibiotics. 50% (n = 13) of EPEC and 61.5% (n =8) of ETEC showed multi-drug resistance (MDR) profiles and one EPEC was found to be extensive drug resistant (XDR). In contrast, EHEC isolates were susceptible to the majority of antimicrobial agents. The MDR isolates were positive for blaTEM and blaCTX-M ESBL genes and carried class 1 integrons. Further study on the biofilm formation indicated that, 3 out of 4 EHEC isolates showed strong biofilm, while other pathotypes had either moderate, weak or no biofilm activity. Majority of EPEC isolates were belonged to phylogenetic group B1, all except one ETEC were classified as phylogenetic group A and two EHEC were belonged to phylogroup D, respectively. A multilocus variable tandem repeat analysis (MLVA) exhibited 22 distinct patterns. In conclusion, MLVA data showed high clonal diversity. Presence of EHEC in animal origins pose public health concern in this region.  相似文献   

16.
CS31A is a K88‐related non‐fimbrial adhesin first described on Escherichia coli strains isolated from diarrhoeic and septicaemic calves. In this report, CS31A antigen was screened by immunological methods and confirmed by PCR among bovine E. coli isolates. In addition, CS31A‐producing strains were characterized with respect to different fimbrial antigens, O‐serogroup and other properties related to virulence. Faecal or tissue specimens of 100 diarrhoeic or septicaemic calves and 27 older cattle with different pathologies from 71 outbreaks or individual cases that occurred in Buenos Aires province, Argentina, were examined. CS31A+ E. coli strains were isolated from 21 (21.0%) calves from 16 outbreaks or individual cases. No CS31A+ E. coli was detected in samples from cattle more than 1 year old. Fimbriae F5, F41, F17a and F17b were not detected among the CS31A‐producing strains. Three (14.3%) of the CS31A+ E. coli strains expressed the F17c fimbria. All of the 21 isolates exhibited at least one property of septicaemic strains (resistance to serum, production of aerobactin or colicins) but none of them demonstrated heat‐stable enterotoxigenic activity. CS31A+ E. coli isolates belonged to 10 serogroups, more commonly O8, O7, O17 and O21. The results obtained here confirm the worldwide distribution of CS31A antigen in bovine E. coli strains. However, CS31A+ or CS31A+/F17c+ E. coli were less frequently isolated than they were in North hemisphere countries.  相似文献   

17.
The presence and transfer of antimicrobial resistance genes from commensal bacteria in companion animals to more pathogenic bacteria may contribute to dissemination of antimicrobial resistance. The purpose of this study was to determine antimicrobial resistance gene content and the presence of genetic elements in antimicrobial resistant Escherichia coli from healthy companion animals. In our previous study, from May to August, 2007, healthy companion animals (155 dogs and 121 cats) from three veterinary clinics in the Athens, GA, USA area were sampled and multidrug‐resistant E. coli (n = 36; MDR, resistance to ≥2 antimicrobial classes) were obtained. Of the 25 different plasmid replicon types tested by PCR, at least one plasmid replicon type was detected in 94% (34/36) of the MDR E. coli; four isolates contained as many as five different plasmid replicons. Nine replicon types (FIA, FIB, FII, I2, A/C, U, P, I1 and HI2) were identified with FIB, FII, I2 as the most common pattern. The presence of class I integrons (intI) was detected in 61% (22/36) of the isolates with eight isolates containing aminoglycoside‐ and/or trimethoprim‐resistance genes in the variable cassette region of intI. Microarray analysis of a subset of the MDR E. coli (n = 9) identified the presence of genes conferring resistance to aminoglycosides (aac, aad, aph and strA/B), β‐lactams (ampC, cmy, tem and vim), chloramphenicol (cat), sulfonamides (sulI and sulII), tetracycline [tet(A), tet(B), tet(C), tet(D) and regulator, tetR] and trimethoprim (dfrA). Antimicrobial resistance to eight antimicrobials (ampicillin, cefoxitin, ceftiofur, amoxicillin/clavulanic acid, streptomycin, gentamicin, sulfisoxazole and trimethoprim‐sulfamethoxazole) and five plasmid replicons (FIA, FIB, FII, I1 and I2) were transferred via conjugation. The presence of antimicrobial resistance genes, intI and transferable plasmid replicons indicate that E. coli from companion animals may play an important role in the dissemination of antimicrobial resistance, particularly to human hosts during contact.  相似文献   

18.
A total of 1002 Escherichia coli strains isolated from pre‐weaned pigs with diarrhoea on 1114 swine farms were screened for the presence of the adhesin involved in diffuse adherence (AIDA) gene by polymerase chain reaction (PCR). Escherichia coli isolates that carried AIDA genes were also tested by PCR for the detection of five fimbriae (F4, F5, F6, F18 and F41), heat‐stable (STa, STb) and heat‐labile (LT) enterotoxin, enteroaggregative E. coli heat‐stable enterotoxin 1 (EAST1), and Shiga toxin 2 oedema disease (Stx2e) genes. Twenty‐three (2.3%) of the 1002 E. coli isolates carried the gene for AIDA. Among 23 isolates shown to carry genes for AIDA, three carried the AIDA gene as the only shown virulence factor. Other isolates carried other virulence factor genes in addition to AIDA. Four isolates carried genes for at least one of the fimbrial adhesins and enterotoxins. Sixteen isolates carried genes for enterotoxins only. The AIDA may represent an additional virulence determinant in pre‐weaned pigs with diarrhoea.  相似文献   

19.
1. The aim of this study was to investigate the occurrence of aminoglycoside resistance and the prevalence of 6 important modifying enzyme genes, i.e. (strA, strB, aph(3?′)-IIa, aac(3)-IIa, aac(6?′)-Ib and ant(3?″)-Ia), in Escherichia coli strains in broilers with septicaemia in Hebei, China.

2. A total of 111 clinical isolates of E. coli were collected from 46 large-scale farms. Antimicrobial susceptibility tests, using the Kirby–Bauer disc diffusion method, were performed on all 111 isolates. In addition, all were screened for the presence of modifying enzyme genes using the polymerase chain reaction (PCR).

3. The results show that the rates of resistance were as follows: streptomycin: 97.3%, kanamycin: 97.0%, gentamicin: 95.5%, neomycin: 50.5%, amikacin: 46.0%, spectinomycin: 22.5%. Of the genes examined, strB (73.9%) was the most frequently identified gene in the phenotypic resistant isolates, followed in order by: ant(3?″)-Ia, aac(3)-IIa, aac(6?′)-Ib, aph(3?′)-IIa and strA.

4. It is concluded that aminoglycoside resistance in E. coli from broilers with septicaemia remains a serious problem in Hebei, China. This emphasises the need to ban the non-therapeutic use of antibiotics, discourage their misuse and to be continually vigilant by providing appropriate scientific and technological support for the poultry industry.  相似文献   

20.
Waste milk samples from 103 farms in England and Wales were examined for the presence of β-lactam antibiotics and ESBL-producing Enterobacteriaceae. Approximately 10 months after the initial sampling, further waste milk, environmental and faecal samples from farms shown to be positive for CTX-M Escherichia coli were investigated further. Isolates with an ESBL phenotype were tested by PCR for the presence of blaCTX-M, blaOXA, blaSHV and blaTEM genes. Isolates positive for blaCTX-M were sequenced to determine CTX-M type. Representative isolates were further examined by PFGE, plasmid replicon typing and serotyping. Of particular interest, 21.4% of waste milk samples contained residues of the cephalosporin cefquinome, which was significantly associated with CTX-M bacteria. Such bacteria occurred in 5.8% of the waste milk samples (including 3.9% CTX-M E. coli). CTX-M types identified were 1, 14, 14b and 15, but none of the E. coli were serotype O25, the serotype of the human pandemic strain.  相似文献   

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