Comparative bacterial drug resistance in modern battery and free-range poultry in a tropical environment

A correlation between the use of antibiotics and drug resistance was found among Escherichia coli strains isolated from modern battery poultry at the University of Ibadan, Nigeria. All 1248 E coli strains from university poultry and 2196 strains from a commercial poultry farm in Ibadan were resistant to tetracycline, streptomycin and sulphonamide, the minimal inhibitory concentrations of these drugs being found to be several times those of the control E coli NCTC 10418. In contrast, all 2284 strains isolated from free-range town and village poultry were sensitive to these drugs. In the tropical developing countries with poor environmental sanitation and low personal hygiene, this situation has public health implications.     

一例鸡源致病型大肠杆菌的分离鉴定

为进行一例鸡源致病型大肠杆菌的分离鉴定,无菌采集疑似大肠杆菌患病蛋鸡肝脏、脾脏等组织,进行病原菌的分离培养。利用培养特性检查、菌落形态观察、革兰氏染色鉴定、生化特性考察、PCR鉴定、测序分析以及动物致病性试验对分离菌株进行鉴定,并同时进行药敏试验。结果显示,分离菌株为一株致病型大肠杆菌,对青霉素、氟苯尼考、阿莫西林等多种抗生素产生耐药性,对丁胺卡那敏感。建议使用丁胺卡那霉素对大肠杆菌进行防治。     

2019年湖南省部分地区鸡、鸭、猪源大肠杆菌耐药性调查

旨在调查2019年湖南省部分地区不同来源的大肠杆菌对抗生素的耐药水平,为养殖合理用药提供参考。从4个市畜禽养殖场采集猪、鸡和鸭粪便285份,使用麦康凯琼脂培养基和伊红美蓝培养基对大肠杆菌筛选,利用基质辅助激光解析电离飞行时间质谱进行鉴定,采用微量肉汤稀释法检测16种抗生素对大肠杆菌的最小抑菌浓度(MIC)。共分离出203株大肠杆菌(鸡源146株、鸭源20株和猪源37株),对四环素和氨苄西林耐药率最高,分别达到89.2%和84.7%;对头孢他啶、奥格门丁、黏菌素耐药率较低,分别为2.5%、2.0%和0.5%;所有菌株均对美罗培南敏感。抗3种及以上抗生素的菌株数目占比为87.7%,而仅5.42%的菌株对所有检测的抗生素敏感。另外,来源于减抗示范养殖场的大肠杆菌对大部分抗生素的耐药率,与来源于非减抗养殖场大肠杆菌相比未见显著差异。上述结果表明,湖南省动物源大肠杆菌的耐药水平仍处在较高水平,重视兽药使用管理并持续开展对大肠杆菌的耐药性监测十分必要。     

3株猪源大肠埃希氏菌耐药基因的初步定位

本试验旨在对临床分离的猪源大肠埃希氏菌耐药基因进行初步定位。采用常规细菌分离培养、16S rRNA PCR扩增和序列测定方法从江西省3个规模化猪场送检的子宫脓液中分离鉴定病原菌,并通过质粒提取、转化大肠埃希氏菌DH5α感受态细胞及药敏试验对临床分离株的耐药基因进行初步定位。结果显示,分离鉴定到3株大肠埃希氏菌,其中JX-22分离株仅对氧氟沙星、大观霉素敏感,JX-26分离株仅对链霉素、氧氟沙星等4种药物敏感,JX-28分离株仅对氧氟沙星等3种药物敏感,均为多重耐药菌;3株大肠埃希氏菌均可纯化到分子质量大小不一的质粒。分离株、质粒转化菌及大肠埃希氏菌DH5α感受态细胞药敏试验对比结果显示,3株大肠埃希氏菌的耐链霉素、林可霉素、甲硝唑、氨苄西林、阿莫西林、大观霉素、丁胺卡那基因,JX-22和JX-26分离株的耐多西环素、氟苯尼考和复方新诺明基因,JX-22分离株的耐头孢曲松基因,JX-28分离株的耐头孢曲松、头孢噻肟、诺氟沙星基因均定位于细菌质粒上;JX-28分离株的耐多西环素、氟苯尼考和复方新诺明基因,JX-22分离株的耐诺氟沙星基因和JX-26分离株的耐头孢曲松、头孢噻肟基因均定位于其染色体上;3株分离株均无氧氟沙星耐药基因。本试验初步确定3株多重耐药猪源大肠埃希氏菌的大部分耐药基因定位于质粒上,为进一步研究猪源大肠埃希氏菌的耐药机理和有效控制措施奠定基础。     

河西走廊地区犊牛腹泻致病性大肠杆菌分离鉴定、毒力因子及耐药性检测

[目的]为了分析河西走廊地区犊牛腹泻致病性大肠杆菌携带毒力基因和耐药性情况,[方法]2020—2021年在河西走廊地区采集患腹泻病犊牛的粪便、肛拭子及肝脏等病料组织279份,采用人工感染试验动物、PCR方法和K-B药敏纸片法分别检测犊牛腹泻性大肠杆菌致病性、毒力因子和耐药性。[结果]结果表明,分离得到了126株大肠杆菌,其中79株犊牛腹泻性大肠杆菌能引起小鼠死亡;分离的79株致病性大肠杆菌的毒力基因crl、irp2、fimH、papC、K88、K99、stx1、stx2检测率在40.5%～100%之间,其他毒力基因检测率在15.2%～34.2%之间;分离的79株致病性大肠杆菌对氨苄西林、阿莫西林、新霉素等8种药物的耐药率在49.4%～96.2%之间,对其他药物的耐药率在5.1%～32.9%之间。[结论]从河西走廊地区患腹泻病犊牛病料组织中分离得到79株致病性大肠杆菌,这些菌株携带多种毒力基因,对临床中常用的抗菌药物产生了耐药性。     

Incidence of drug resistance and transmissible R factors in strains of E. coli isolated from faeces of healthy pigs

Two hundred and twenty-six strains of E. coli were isolated from faeces of 107 pigs at different ages and without clinical signs of infectious diseases. The resistance of the strains to sulphonamide, tetracycline, streptomycin, chloramphenicol, ampicillin, and nalidixic acid was determined. In 74 % of the animals the predominant E. coli flora was found to be resistant to one or more of the drugs mentioned. Fifty-three % of the strains were resistant. Multiple resistance was predominant among resistant strains (67 %). R factors transmissible to a sensitive strain of E. coli K12 W3132 were demonstrated in 28 %. The proportion of resistant strains was largest in young animals (0–14 weeks) accounting for 65 % of the strains isolated, as compared to 43 % of strains from pigs and sows (6 months or more). The incidence of resistance to sulphonamide, tetracycline, and streptomycin was high, whereas most of the strains were sensitive to ampicillin and chloramphenicol. All strains were sensitive to nalidixic acid.The incidence of resistance to antibiotics in a population of pigs to whom these drugs are not fed but applied as therapeutic agents solely seems rather high. When based on clinical findings only, the value is therefore questionable of sulphonamide, tetracycline and streptomycin treatment of infectious diseases caused by E. coli.     

Use of epidemiologic markers to identify the source of Escherichia coli infections in poultry

During an epidemiologic study of poultry colisepticemia on 2 Saudi Arabian poultry broiler farms, Escherichia coli was isolated from 101 (40.4%) of the 250 specimens examined. The antigenic structure and the drug resistance pattern of 65.4% of the E coli isolates from different sources were used as epidemiologic markers to trace the source of the infection. The predominant E coli serotypes involved in infections of 2 poultry broiler progeny farms were 033:H4 (51.8%) and 078:H- (19.6%) that had the following respective drug resistance patterns: furazolidone-streptomycin-sulfathiazole and streptomycin-sulfathiazole-tetracycline. Escherichia coli strains with typical epidemiologic markers were isolated from various sources on a broiler breeding farm, but not from well waters of the infected progeny farm. Three other E coli serotypes (045:H10[14.3%], 0119:H27[1.8%], and 0145:H25[1.8%]) were involved in poultry infection, but to a lesser extent. These 3 serotypes were multiply resistant against 5 to 6 of the antimicrobials evaluated.     

Antimicrobial resistance of Escherichia coli isolated from chickens

Faecal Escherichia coli isolated from healthy farm chickens, from farm chickens with avian influenza, and from chickens with diarrhoea were more resistant to antimicrobial agents (94-100%) than those isolated from healthy domestic chickens (20%). Transfer of drug resistance was readily achieved from strains isolated from both healthy and sick farm chickens, and from diarrhoeic chickens; it was more difficult to demonstrate in strains from domestic chickens. Resistant E. coli showing serotypes suspected to be enteropathogenic for man, i.e 0126:K71(B16), 044:K74 (L) and 0119:K69(B14), were isolated from faecal samples of healthy and sick farm chickens, but not from healthy domestic birds.     

主要动物性食品生产链大肠杆菌的耐药性分析

为了解主要动物性食品生产链大肠杆菌(Escherichia coli)的耐药情况,采用美国临床和实验室标准协会（CLSI）推荐的微量肉汤稀释法,对源自猪肉、鸡蛋、鸡肉生产链的350株大肠杆菌进行常用10种抗菌药(组合)的敏感性测定,参考CLSI标准（2010）判定药敏结果。结果显示,350株大肠杆菌对四环素（TET）耐药率（82.0%）最高,其次是甲氧苄啶/磺胺甲噁唑（SXT）（75.4%）,对庆大霉素（GEN）耐药率（26.9%）最低。尽管不同来源大肠杆菌对10种抗菌药中大部分药物耐药率较一致,但不同生产链环节的菌株耐药率却存在差异。76.2%（267株）受试菌株多重耐药,其中以8重耐药菌株（17.7%）最多。菌株共产生108种耐药谱,猪肉、鸡肉和鸡蛋生产链中大肠杆菌的耐药谱分别为40、46和55种,但优势耐药谱不明显。菌株数较多的耐药谱为：NAL-CIP-AMP-AMC-CEF-SPT-GEN-SXT-TET（21/350）、TET（20/350）、NAL-CIP-AMP-AMC-CEF-SPT-SXT-TET（16/350）、NAL-CIP-AMP-CEF-FLO-SPT-SXT-TET（16/350）及SPT-SXT-TET（15/350）。提示,主要动物性食品生产链大肠杆菌耐药情况较严重,应加强其耐药性连续监测与控制。     

仔猪致病性大肠杆菌的分离鉴定与耐药性分析

由湛江市3个养猪场采集到40份仔猪黄痢、白痢腹泻粪便样品,共分离到40株大肠杆菌,其中7株是致病性大肠杆菌,三个猪场致病性大肠杆菌的分离率分别为15.4%、10%和43%。对7株致病性大肠杆菌进行药物敏感性试验,结果表明:它们均对恩诺沙星、菌必治和丁胺卡那霉素敏感,而对复方新诺明、阿莫西林、氨苄青霉素、四环素和庆大霉素的耐药率为100%,对氯霉素、头孢氨苄和痢特灵的耐药率为85.7%,对卡那霉素和链霉素的耐药率为57.1,%对氟哌酸和环丙沙星的耐药率为14.3%。猪场选用较敏感药物来防治仔猪大肠杆菌病,使疫病得到了有效控制。     

A preliminary study of Salmonella, verocytotoxigenic Escherichia coli/Escherichia coli O157 and Campylobacter on four mixed farms

The aims of this study were to investigate the incidence of Salmonella, verocytotoxigenic Escherichia coli (VTEC)/Escherichia coli O157 and Campylobacter on four mixed farms and to characterize the isolates in terms of a range of virulence factors. Eighty-nine composite (five different samples from the same animal species combined) faecal [cattle (24), pigs (14), sheep (4), poultry (4), horses (7), deer (4), dogs (9), rodents (2) and wild birds (20)] samples, 16 composite soil samples plus 35 individual water samples were screened using culture-based, immunomagnetic separation and molecular methods. Salmonella was detected in bovine faeces, cattle and poultry house water. Salmonella serotypes/phage types included Dublin, Kiel and Typhimurium DT193, and most isolates were spvC, invA and rck positive. The pefA and rck genes were found exclusively in the non-Typhimurium strains, while Salmonella Dublin and Salmonella Kiel strains carried Salmonella genomic island I marker(s). VTEC/E. coli O157 were found in deer and dog faeces only. The E. coli O157 isolate was an enteroinvasive E. coli, while the VTEC isolate was untypable but carried the vt1, eaeA, hlyA, tir and eptD genes. This article reports the first confirmed carriage of E. coli O157 in Irish deer. Campylobacter species were not detected over the course of this study. It was concluded that [1] Salmonella, VTEC and Campylobacter have low (<5%) prevalence or are absent on the farms in this study; [2] water was an important source of bacterial pathogens; [3] both dogs and deer may act as a source of pathogenic E. coli and [4] key virulence and resistance determinants are widespread in farm Salmonella strains. This study highlights the need to control water as a source of pathogens and suggests that the domestic pets and deer should be considered in any farm risk assessment.     

不同省区鸡源大肠杆菌耐药性调查与系统进化群分析

为有效控制鸡大肠杆菌病,对不同省区鸡源大肠杆菌致病菌株的分布情况及耐药特征进行了调查分析,分别采用PCR法和MIC法进行了系统进化群分群检测和药敏试验,采用皮下注射进行了动物致病性试验,并采用SPSS17．0软件进行差异显著性分析。结果显示：低致病群B1（38．13％）和非致病群A（34．02％）菌株分布相对较多,其次是高致病群D（21．23％）和B2（6．16％）;鸡源大肠杆菌耐药严重,12种药物的耐药率在50％以上,多重耐药问题突出,多重耐药率高达98．86％;不同省区鸡源大肠杆菌菌株的耐药程度存在差异,个别药物（如奥格门丁、头孢噻呋等）差异显著;高致病群B2和D群菌株的耐药程度较B1和A群菌株严重,其中氧氟沙星、庆大霉素、大观霉素、头孢噻呋、磺胺异噁唑、复方新诺明、奥格门丁等7种药物差异显著（ P＜0．05）。试验表明,我国鸡源大肠杆菌高致病菌株检出率高,且耐药程度相对严重,在适宜条件下更易导致鸡群发病且较难控制。     

Prevalence of and resistance to anti-microbial drugs in selected microbial species isolated from bulk milk samples

The prevalence of strains of Staphylococcus aureus, coagulase-negative (CN) staphylococci, Listeria monocytogenes, Escherichia coli, Enterococcus faecalis, E. faecium and Bacillus cereus, was investigated in 111 bulk milk samples. Staphylococcus aureus was isolated from 38 samples, CN staphylococci from 63 samples, E. coli from 49 samples, E. faecalis or E. faecium from 107 samples, and L. monocytogenes from two samples. Bacillus cereus was not found in any of the samples and three samples were free of any of the selected species. Sensitivity to the anti-microbial drugs amikacin, ampicillin, ampicillin + sulbactam, cephalothin (CLT), cephotaxime, clindamycin, chloramphenicol (CMP), co-trimoxazole, erythromycin (ERY), gentamicin, neomycin, norfloxacin, oxacillin, penicillin, streptomycin (STR), tetracycline (TTC) and vancomycin was tested using the standard dilution technique. Minimum inhibitory concentration (MIC) characteristics (MIC50, MIC90, MIC range) were determined for each microbial species. Resistance against one or more anti-microbial drugs was found in 93% of S. aureus, 40% of CN staphylococci, 73% of E. coli, 88% of E.faecalis, 55% of E.faecium, and one L. monocytogenes strain. Most of the strains, particularly enterococci, were resistant to STR, TTC, and ERY (MIC50 4 microg/ml). A high percentage of staphylococci were resistant to beta-lactam antibiotics. High resistance to CLT was found in 11 strains of E. coli (MIC 256 microg/ml) and strains resistant to CMP (MIC90 16 microg/ml) were detected. The highest numbers of resistance phenotypes were found in E. coil (16) and CN staphylococci (12). Eighteen identical resistance phenotypes were demonstrated in indicator bacteria (E. coli, E. faecalis, E. faecium) and pathogens (S. aureus, CN staphylococci) isolated from the same bulk milk sample. The obtained resistance data were matched against the herd owners' information on therapeutic use of the drugs. This confrontation could not explain the findings of strains resistant to ERY or CMP. Our findings are evidence of selection of resistant strains among not only pathogenic agents, but also among indicator bacteria which can become significant carriers of transmissible resistance genes.     

仔猪腹泻致病性大肠杆菌分型鉴定及耐药性分析

为了解贵州省规模化养猪场腹泻仔猪致病性大肠杆菌流行情况及耐药性变化,本研究运用凝集试验、PCR和药敏纸片琼脂扩散法等方法对分离的78株致病性大肠杆菌进行血清型、毒力基因及耐药性分析。结果显示,78株致病性大肠杆菌以O138、O87血清型为主,占定型菌株的60.8%;其中62株致病性大肠杆菌检出毒力基因,检出率为79.5%,可分为8种毒力基因类型,分属肠致病性大肠杆菌（EPEC）、肠产毒性大肠杆菌（ETEC）和肠聚集性大肠杆菌（EAEC）,毒力基因eaeA、elt和escV检出率较高,分别为38.5%、28.2%和21.8%;分离到的致病性大肠杆菌对β-内酰胺类药物高度耐药,均为多重耐药株,耐药种类可达8种以上。结果表明,当前贵州省规模化养猪场腹泻仔猪致病性大肠杆菌的毒力基因检出率较高且基因型复杂,耐药性严重。本试验结果可为规模化养猪场防控仔猪腹泻提供基础资料及理论依据。     

山东省部分地区禽源致病性大肠杆菌的血清流行病学调查与耐药性检测

为调查山东省禽源致病性大肠杆菌流行的血清型及耐药性,从山东部分地区的45家养禽场分离到致病性大肠杆菌96株,应用微量平板凝集试验进行了血清型鉴定,共鉴定出18种血清型,其中优势血清型6种,分别为O78、O2、O15、O18、O143、O88,占定型致病性菌株的64％。抗菌药物敏感性试验发现,96株大肠杆菌对20种药物有不同程度的耐药性。75％以上的菌株对氨苄青霉素、阿莫西林、土霉素等5种抗菌药耐药,50％以上的菌株对卡那霉素、多西环素、环丙沙星等7种抗菌药表现为耐药;所有分离株存在多重耐药现象,75％的受检菌对9种或9种以上的被测药物耐药。结果表明,O78、O2、O15、O18、O143、O886种血清型是山东省部分地区近年来禽源致病性大肠杆菌的优势血清型,且禽源致病性大肠杆菌的耐药现象严重,有必要加强耐药性检测,以指导兽医临床合理使用抗菌药物。     

Phenotypic and genotypic characterization of virulence factors of Escherichia coli isolated from broiler chickens with simultaneous occurrence of cellulitis and other colibacillosis lesions.

The objective of this study was to characterize virulence factors of Escherichia coli isolates from broilers with simultaneous occurrence of cellulitis and other colibacillosis lesions. Thirty flocks were sampled and 237 birds with cellulitis were examined. Eighty-two (34.6%) of 237 birds condemned for cellulitis had gross lesions in the heart, air sacs, joints, or liver. In 58 chickens, E. coli was isolated from both the cellulitis and other lesions of colibacillosis, and 18.9% of the E. coli isolates from the 2 types of lesions belonged to the same O group. Escherichia coli of serogroups O78, O1, and O2 predominated. Isolates of the same serogroup that were derived from different lesions in the same birds had similar patterns of biotype, aerobactin production, serum sensitivity profile, antibiotic sensitivity, and K1 capsule production. Escherichia coli derived from cellulitis lesions produced virulence factors similar to those found in E. coli isolated from other colibacillosis lesions in poultry.     

Comparison of antimicrobial resistant Escherichia coli in wild and captive Japanese serows.

The fecal Escherichia coli isolated from wild Japanese serows living in mountainous areas away from humans and those from captive serows kept in human areas were examined for antimicrobial resistance and the possession of transferable R plasmids. Of 874 E. coli strains isolated from 283 wild serows in 1980-1981, only 11 (1.3%) were resistant to at least one of 6 antimicrobial drugs; ampicillin, streptomycin, tetracycline, chloramphenicol, kanamycin and sulfadimethoxin. Seven (2.5%) individuals were found to carry resistant E. coli. To heighten the isolation frequency of drug-resistant strains, fecal samples of 244 wild serows in 1983-1984 were cultured directly onto drug-supplemented media. Only 12 (4.9%) serows were shown to have drug-resistant E. coli. No transferable R plasmid was detected among a total of 87 resistant strains from wild serows. In contrast, all 33 captive serows except one which was kept only one day after capture, showed resistant E. coli and 20 (60.6%) serows were excreting R plasmid-carrying E. coli. Of 161 drug-resistant strains from captive serows, 50 (31.1%) were found to carry R plasmids. Wild serows seemed to readily change to harbor resistant E. coli almost as soon they were reared in human areas without direct exposure to drugs. These results lead to the conclusion that drug-resistant E. coli can probably be used as microbial indicator for natural environmental pollution.     

Antibiotic resistance of Escherichia coli strains isolated from chickens with colisepticaemia in Morocco

Sixty-two strains of Escherichia coli were isolated in 58 farms from broiler chickens showing respiratory signs and lesions characteristic of avian colibacillosis. Serological examination of these strains showed that the types 078, 01 and 02 (for the somatic antigen) and K1 (for the capsular antigen) were the most frequently found. Newcastle disease virus was also isolated in two cases. All the strains of E. coli isolated were sensitive to colistin, flumequine and gentamicin. A few strains were resistant to neomycin, nalidixic acid and trimethoprim. The frequency of strains resistant to nitrofurans, sulfonamides, chloramphenicol, spectinomycin and ampicillin was intermediate. Most strains were resistant to tetracycline. Multiple resistance was common.     

新疆石河子地区奶牛乳房炎大肠杆菌的分离鉴定及耐药性分析简

本试验旨在调查新疆石河子地区奶牛乳房炎源大肠杆菌的某些生物学特性及其耐药状况,以提高药物疗效,减少牛奶中药物的残留。试验从新疆石河子地区患乳房炎奶牛的乳样中分离纯化并鉴定出21株大肠杆菌,并对大肠杆菌分离株进行抗菌药物敏感性分析。结果表明,21株大肠杆菌对21种抗菌药物中的6种药物耐药率超过50%,其中最多的耐药15种,最少的耐药5种,耐药6及6种以上的菌株共占到76.19%。提示,该地区奶牛乳房炎源大肠杆菌对多种药物已产生了不同程度的耐药性,且存在严重的多重耐药情况。     

雏鸡大肠埃希菌的分离鉴定及药敏试验

对长春市某鸡场送检的10只2日龄疑似患大肠埃希菌病死亡的雏鸡进行了实验室诊断。无菌采集病死鸡的心、肝、脾、肺、肾等组织,通过细菌检测、PCR鉴定、生化试验、血清型鉴定、动物回归试验等系统鉴定,确定其为大肠埃希菌。分离菌药敏试验结果表明,该菌株对复方新诺明、庆大霉素、链霉素等药物敏感,对丙氟哌酸、恩诺沙星、氨苄青霉素、左氟沙星等大多数抗菌药物高度耐药。