安徽地区禽源沙门氏菌分离鉴定与耐药性研究

为了解安徽地区禽源沙门氏菌的流行菌株和耐药情况,本研究通过培养特性、镜检、生化试验、PCR和血清型鉴定等,对疑似发病禽的116份病料进行沙门氏菌分离鉴定,并采用Kindy-Bauer法对分离菌株进行耐药性分析。试验共分离到42株禽源沙门氏菌,其中包含5个大群11种血清型。B群30株、A群2株、D群7株、C₁群2株、C₂群1株,其中以B群鼠伤寒沙门氏菌为优势菌株。42株分离菌对阿米卡星、左氧氟沙星和环丙沙星的耐药率均低于20%,而对氨苄西林、链霉素、呋喃唑酮、大观霉素、复方新诺明和多西环素的耐药率达50%以上,其中对氨苄西林的耐药率达97.62%,且41株分离菌株存在多重耐药。结果表明,目前安徽地区禽源沙门氏菌优势流行株是鼠伤寒沙门氏菌,流行菌株呈现较严重的耐药性。本研究为指导临床用药及禽源沙门氏菌的综合防制提供数据支撑。     

华中地区鸡源沙门菌分离鉴定及耐药性分析

为了探明华中地区种鸡场沙门菌(Salmonella)的优势血清型和耐药情况,本研究从湖北、河南、湖南等省市22个规模化鸡场采集病鸡、死胚及弱雏组织样品3 724份,通过分离培养、生化试验、PCR鉴定及血清型试验确定分离菌种属及其血清型,并采用Kirby-Bauer法对分离菌株进行了耐药性分析。结果显示,本试验从3 724份病料中共分离鉴定出124株沙门菌,其中79株为D群肠炎沙门菌(63.71%,79/124),34株为D群鸡白痢沙门菌(27.42%,34/124),8株为B群鼠伤寒沙门菌(6.45%,8/124),有3株沙门菌未能确定血清型。O抗原鉴定79株肠炎沙门菌和34株鸡白痢沙门菌为O9,8株鼠伤寒沙门菌为O4。H抗原鉴定79株肠炎沙门菌为Hg,m,8株鼠伤寒沙门菌为Hi。药敏试验结果显示,124株分离菌株对萘啶酸、氨苄青霉素、四环素和多西环素耐药率分别为95.97%(119/124)、91.94%(114/124)、57.26%(71/124)和70.16%(87/124);对复方新诺明和红霉素耐药率分别为25.81%(32/124)和12.10%(15/124);对氯霉素、庆大霉素、头孢噻肟和卡那霉素耐药率分别为6.45%(8/124)、1.61%(2/124)、1.61%(2/124)和0.81%(1/124);对左氧氟沙星、阿米卡星和多黏菌素B完全敏感。99.19%(123/124)的分离株至少对一种药物耐药,87.10%(108/124)的分离株表现多重耐药。本研究为华中地区养鸡场沙门菌的诊断及防控提供了数据支撑。     

Isolation,Identification and Drug Resistance Analysis of Interstinal Pathogenic Escherichia coli and Salmonella Isolated from Diarrhea Piglets

In order to find out the serotype, resistant phenotype and genotype of Escherichia coli (E. coli) and Salmonella in piglets, this study collected 128 samples of diarrhea piglets from seven large-scale pig farms in five cities in Guizhou province, and the E. coli and Salmonella were isolated and identified. The pathogenicity of the strain was identified by animal test. The drug resistance of the main pathogen was tested by drug susceptibility paper. The resistance gene of each pathogen was detected by PCR. The drug resistance and genotype correlation of the bacterial were analyzed. The results showed that 78 strains of pathogenic E. coli and 21 strains of Salmonella were isolated and identified in this study. The serotypes of pathogenic E. coli were predominantly O138 and O87. Salmonella Typhimurium and Salmonella Enteritidis were predominant serotypes. The susceptibility test showed that the resistant strains of 78 strains of E. coli were more than 80% resistant to β-lactams and more than 40% for other antibacterials. The resistance rate of 21 strains of Salmonella to aminoglycosides was more than 50% and more than 20% to other types of antibacterials; 12 and 10 kinds of drug resistance-related genes of E. coli and Salmonella were detected, respectively; The coincidence rate of resistant genotype and phenotype of two kinds of bacteria were above 60%, and both were multiple drug resistance. This study provided a theoretical basis for comprehensive prevention and control of piglets diarrhea.     

腹泻仔猪肠道致病性大肠埃希氏菌和沙门氏菌的分离鉴定与耐药性研究

为探明仔猪细菌性腹泻肠道致病性大肠埃希氏菌和沙门氏菌流行的血清型、耐药表型及耐药基因型,本试验采集了贵州省5个地（州）市7个规模化养猪场的128份腹泻仔猪肠道样本,并对采集的样本进行了大肠埃希氏菌和沙门氏菌分离与鉴定,通过动物试验鉴定菌株的致病性,利用血清学方法鉴定其血清型,并通过药敏纸片法对主要致病菌进行耐药性研究,采用PCR技术检测各致病菌株耐药相关基因,分析细菌耐药表型和耐药基因型相关性。结果显示,本研究共分离鉴定到78株致病性大肠埃希氏菌与21株沙门氏菌,致病性大肠埃希氏菌血清型以O138、O87为主,沙门氏菌血清型以鼠伤寒沙门氏菌、肠炎沙门氏菌居多;药敏试验结果表明,本试验分离到的78株致病性大肠埃希氏菌对β-内酰胺类药物耐药率达80%以上,对其他种类的抗菌药耐药率均超过40%,分离鉴定的21株沙门氏菌对氨基糖苷类药物耐药率达50%以上,对其他种类的抗菌药耐药率均达20%以上;本试验分离鉴定的致病性大肠埃希氏菌共检出12种耐药相关基因,沙门氏菌共检出10种耐药相关基因,两种细菌耐药基因型与耐药表型符合率均达60%以上,且均为多重耐药。本研究为仔猪腹泻的综合防控提供了理论依据。     

Antimicrobial resistance in Salmonella enterica serovars Enteritidis and Typhimurium isolated from animals in Korea: comparison of phenotypic and genotypic resistance characterization

Fourteen and 22 each of Salmonella Enteritidis and Salmonella Typhimurium (S. Typhimurium) were isolated from animals from 1983 to 1999 in Korea and tested for their antibiotic resistance patterns, phage types and resistance gene patterns. S. Typhimurium isolates were highly resistant to streptomycin, sulfisoxazole and tetracycline, 95, 95 and 86%, respectively. The incidence of multiple antibiotic resistance (resistant to more than two drugs tested) of S. Typhimurium isolates was extremely high (100%) comparing to S. Enteritidis isolates (21%). Two of the five ACSSuT (ampicillin, chloramphenicol, streptomycin, sulfisoxazole and tetracycline) resistant type S. Typhimurium isolates were phage type definitive type 104 (DT104).For the detection of resistance related genes in S. Enteritidis and S. Typhimurium isolates, particularly ACSSuT type S. Typhimurium, antibiotic resistance genes, cmlA/tetR, bla(PSE-1) and bla(TEM), and genus Salmonella specific gene, sipB/C, were amplified using four pairs of primers in a hot-start multiplex polymerase chain reaction (PCR). Two Korean isolates of S. Typhimurium DT104 showed bla(TEM) amplicons instead of bla(PSE-1) for the ampicillin resistance and they were susceptible to florfenicol. The multiplex PCR used in this study was useful in characterization of multiple drug resistant Salmonella isolates, especially ACSSuT type S. Typhimurium, and identification of beta-lactamase gene distribution among Salmonella isolates.     

广西畜禽产品中沙门氏菌血清型、耐药性及耐药基因调查

试验旨在了解广西部分地区畜禽产品中沙门氏菌血清型分布和耐药状况,以及β-内酰胺酶bla_TEM、bla_CTX-M基因和氟喹诺酮类抗生素耐药基因qnrA、oqxA、oqxB、aac（6'）-Ⅰ b-cr的流行情况。对沙门氏菌进行分离鉴定与血清型分型,采用K-B纸片法对其中随机挑选的80株分离株进行24种抗菌药物敏感性试验,并采用PCR方法进行耐药基因检测。结果显示,从零售生鲜畜禽肉中分离的176株沙门氏菌分属5个血清群,共26种血清型,主要优势血清群为B群60.23%（106/176）、E群18.75%（33/176）和C群15.91%（28/176）,主要优势血清型为德尔卑沙门氏菌35.23%（62/176）、鼠伤寒沙门氏菌11.93%（21/176）和伦敦沙门氏菌9.66%（17/176）。80株分离株对24种抗菌药物均产生不同程度的耐药,其中对复方新诺明、林可霉素、利福平的耐药率最高,均高于90.00%,对青霉素、氨苄西林、阿莫西林、强力霉素、头孢拉啶、头孢氨苄、头孢曲松、头孢他啶、头孢噻肟、阿奇霉素的耐药率介于50.00%~90.00%之间,对环丙沙星、氧氟沙星、氟苯尼考的耐药率小于10.00%;所有分离株均为多重耐药株,其中最少为2重耐药,最多为17重耐药,多重耐药性主要集中在10~16重耐药,共占总数的78.75%（63/80）。PCR结果显示,80株分离株各基因的检出率分别为：bla_TEM 98.75%（79/80）、bla_CTX-M 26.25%（21/80）、oqxA 26.25%（21/80）、oqxB 21.25%（17/80）、qnrA 16.25%（13/80）、aac（6'）-Ⅰb-cr 50.00%（40/80）。结果表明,广西畜禽产品源沙门氏菌血清型呈多样性分布,分离株的耐药情况严重,临床日益严重的耐药现象与耐药基因的普遍存在有很大的关系。     

Isolation,Identification and Analysis of Serotype and Antibiotic Susceptibility of Pathogenic Salmonella from Chickens

To investigate the situations of predominant strain and antibiotic resistance of pathogenic Salmonella from chickens in Guangxi Zhuang Autonomous region, Salmonella was pre-enriched and isolated from tissues of clinical suspected chickens, and the Salmonella isolates were identified by biochemical test using ID 32E System for the identification of Enterobacteriaceae of VITEK System ATB Expression, serotypes were determined by slid agglutination test, antibiotic susceptibility was analyzed by ATB VET Susceptibility Test Strip of Enterobacteriaceae antibiotics.The results showed that 34 Salmonella strains were obtained from 310 clinical samples, of which 1 strain belonged to A serogroup, 1 to C2 serogroup, 15 to B serogroup, 14 to D serogroup and 3 to untyped serogroup, and S.typhimurium of B serogroup and S.pullorum of D serogroup were the predominant serotypes.All Salmonella isolates were sensitive to meropenem, imipenem, spectinomycine and apramycine, and the resistance rates to chloramphenicol, kanamycine and gentamicine were less than 10%, and the resistance rates to amoxicillin, streptomycine, flumequine, oxolinique, sulfamethizol, tetracycline and nitrofurantoine ranged between 50% and 90%, while the resistance rates to penicilline, oxacilline, fusidique, rifampicine and metronidazole reached to 100%.The results indicated that the serotype distribution of pathogenic Salmonella from chickens exhibited regional characteristics, and S.typhimurium and S.pullorum were the predominant serotypes in Guangxi Zhuang Autonomous region, and antibiotic resistance of Salmonella isolates was very serious which should be highly concerned.     

鸡源致病性沙门氏菌的分离鉴定及血清型和药物敏感性分析

为了解当前广西鸡源致病性沙门氏菌的优势流行菌株及耐药情况,掌握其最新流行特点,本试验采集疑似病鸡的组织病料,对沙门氏菌进行增菌和分离培养,运用VITEK System ATB Expression法ID 32E肠杆菌鉴定试剂条对分离菌株进行生化试验鉴定,应用玻片凝集试验进行血清型鉴定,采用ATB VET药敏试剂条对30种肠杆菌抗菌药物进行药物敏感性试验。结果显示,从310份疑似鸡病料中分离鉴定出34株致病性沙门氏菌;这些分离菌株中有A群1株、C2群1株、B群15株和D群14株,另有3株未定型,其中以B群鼠伤寒沙门氏菌和D群鸡白痢沙门氏菌为优势菌株;34株分离株均对美洛培南、亚胺培南、大观霉素和安普霉素敏感,对氯霉素、卡那霉素、庆大霉素的耐药率小于10%,对阿莫西林、链霉素、氟甲喹、噁喹酸、磺胺甲噁唑、四环素和呋喃妥因耐药率介于50%和90%之间,而对青霉素、苯唑西林、夫西地酸、利福平和甲硝唑的耐药率达到100%,并且存在多重耐药现象。结果表明,鸡源致病性沙门氏菌的流行菌株具有一定的地域性,当前广西以鼠伤寒沙门氏菌和鸡白痢沙门氏菌为主,流行菌株耐药性严重,应高度关注。     

上海市零售禽肉制品和活禽中沙门氏菌血清型与耐药性研究

为掌握上海市沙门氏菌在农贸市场和超市禽肉制品和活禽中的污染状况、流行血清型和耐药情况,本试验从320份2012年采集的禽肉样本(240份)和活禽泄殖腔棉试子(80份)中共分离鉴定出沙门氏菌70株,阳性率为21.9%。血清型鉴定结果表明,共鉴定出11种不同的血清型,其中肠炎沙门氏菌占47.1%、印第安纳沙门氏菌占17.1%、鼠伤寒沙门氏菌和德尔卑沙门氏菌均占8.6%。通过纸片法对这70株沙门氏菌进行了16种常用抗菌药物的药敏试验,结果表明,沙门氏菌对奈啶酸耐药率最高,达75.7%,对磺胺异唑、链霉素和氨苄西林耐药率较高,分别为60.0%、60.0%和51.4%。除亚胺培南外,其他药物均有不同程度的耐药菌株。有40株(57.1%)沙门氏菌呈多重耐药表型,耐药性最强的菌株可以对14种抗菌药产生耐药性。本研究对沙门氏菌病的防控及指导临床合理用药具有重要的现实意义。     

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。     

全基因组测序技术在猪源沙门氏菌血清分型和耐药性分析中的应用

【目的】为研究全基因组测序技术在猪源沙门氏菌血清型和耐药性检测方面的应用能力。【方法】以60株猪源沙门氏菌为研究对象,应用传统玻片凝集法和微量肉汤稀释法对其进行血清分型和耐药性检测,并提取所有菌株核酸进行全基因组测序组装,利用SeqSero2和ResFinder4在线预测每株菌的血清型和耐药基因,然后与传统方法进行比较分析。【结果】血清凝集试验共鉴定出8种沙门氏菌血清型,而全基因组测序鉴定出9种血清型,二者分型结果的符合率为90.0%;对11种抗菌药物的药敏试验显示：沙门氏菌对四环素（73.3%）的耐药率最高,其次为氨苄西林（66.7%）、磺胺异噁唑（66.7%）和复方新诺明（53.3%）,基于全基因组预测的恩诺沙星、美罗培南、头孢噻呋和阿奇霉素的耐药性与药敏试验结果完全一致,对氨苄西林、磺胺异噁唑、四环素预测的结果符合率也均大于90.0%。【结论】全基因组测序分析的沙门氏菌血清型和耐药性与常规检测方法的符合率较高,且具有操作简便的优势,可以作为分析沙门氏菌血清型和耐药性的有效方法。     

Assessment of antibiotic resistance phenotype and integrons in Salmonella enterica serovar Typhimurium isolated from swine

Salmonella enterica serovar Typhimurium (S. Typhimurium) isolated and identified from swine were subjected for the analysis of antibiotic resistance pattern and clinically important class 1 and 2 integrons. In addition, S. Typhimurium isolates exhibiting ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, tetracycline and florfenicol (ACSSuTF) resistance pattern as described in most Salmonella enterica serotype Typhimurium definitive type 104 (DT104) were characterized by polymerase chain reaction. All the isolates were resistant to more than four antibiotics and showed the highest resistance to streptomycin (94.1%), followed by tetracycline (90.1%), ampicillin (64.7%), chloramphenicol (56.8%) and gentamicin (54.9%). MIC value for the ten isolates ranged between 0.125-2 mug/ml for ciprofloxacin. Among the beta-lactams used, only one of the isolate exhibited resistance to ceftiofur (MIC 8 microg/ml). Sixty eight percent of these multi drug resistance (MDR) S. Typhimurium isolates carried clinically important class 1 integron with 1kb (aadA) and/or 2kb (dhfrXII-orfF-aadA2) resistance gene cassettes. This study reports the increasing trend of multi drug resistance (MDR) S. Typhimurium with clinically important class 1 integron in pigs. In addition, emergence of the ACSSuTF-type resistance in S. Typhimurium PT other than DT104 may limit the use of resistance gene markers in its detection methods by PCR.     

Sero types, phage types and antibiotic susceptibilities of Salmonella strains isolated from horses in The Netherlands from 1993 to 2000

We studied 232 Salmonella strains from horses with salmonellosis in The Netherlands, isolated in the period from 1993 to 2000 in order to provide insight in the dynamics of sero-, phage types (pt) and antibiotic susceptibilities over time. The strains were tested for susceptibility to seven antimicrobial agents using the agar diffusion method. In addition, the isolates were sero typed and Salmonella enterica subspecies enterica Typhimurium and Enteritidis strains were further phage typed. S. Typhimurium strains of phage type 506 and 401 (both classified as DT 104 in the English phage typing system) were additionally tested for their susceptibility to chloramphenicol (C), streptomycin (S) and sulfonamides (Su). Resistance was common against tetracycline and ampicillin. Most strains were susceptible to enrofloxacin (Enr) and ceftiofur (Cef). Resistance to tetracycline (T), kanamycin (K), ampicillin (A) and trimethoprim/sulfonamide (Sxt) combinations decreased from 1993 to 2000, whereas the resistance to gentamicin (G), ceftiofur and enrofloxacin was stable over time. S. Typhimurium was the predominant serovar and showed more (multiple) resistance compared to other Salmonella serovars. Sixteen different resistance patterns were found, with resistance to T alone and the combination of ACSSuT and AKSxtT being the most common. The multiresistant S. typhimurium phage type 506 (DT 104) was the most common phage type isolated from horses and most of these strains showed the pentadrug resistance pattern ACSSuT. The S. Typhimurium phage type 401 (DT 104) was also found frequently with an ASSuT resistance pattern. The most common S. Typhimurium phage types in horses corresponded with those found in humans, pigs and cattle in the same period in The Netherlands.     

Characteristics of Salmonella isolated from animals at a veterinary medical teaching hospital

Salmonella belonging to 47 serotypes was isolated from animals at the University of California Veterinary Medical Teaching Hospital during the years 1974 to 1983. Salmonella belonging to 12 serotypes accounted for 89% of the 725 isolates. Salmonella typhimurium (including var copenhagen) was the most commonly isolated serotype, but during 1981 to 1983, S krefeld and S saint-paul were predominant. Certain serotypes seemed to be isolated more frequently from extraintestinal sources (S typhi-suis, S dublin). Although resistance to ampicillin, kanamycin, neomycin, streptomycin, and sulfonamides was common (greater than 60% of the isolates were resistant), resistance to chloramphenicol, gentamicin, and trimethoprim-sulfonamides was infrequent, except for isolates of S krefeld and S saint-paul.     

Salmonella isolates from cloacal swabs and footpads of wild birds in the immediate environment of Tokyo Bay

A total of 328 cloacal swabs and 163 footpads of wild birds were investigated for the presence of salmonellae. All 19 isolates from cloacal swabs were serotyped as Salmonella Typhimurium susceptible to all five conventional antimicrobial agents (ampicillin, chloramphenicol, streptomycin, oxytetracycline and nalidixic acid) tested. In contrast, 15 salmonellae isolated from footpads included S. Muenhen, S. Virchow, S. Bareily and S. Bovismorbificans, including S. Typhimurium; these non-Salmonella Typhimurium isolates showed multiple drug resistance.     

Prevalence and antimicrobial resistance of Salmonella spp. in non-diarrhoeic dogs in Trinidad

The estimated prevalence and antimicrobial resistances of Salmonella spp. in non-diarrhoeic dogs across Trinidad was determined. The serotypes of Salmonella spp. isolated were also identified. Of a total of 1391 dogs sampled, 50 (3.6%) were positive for Salmonella spp. with 28 different serotypes, the predominant serotypes were Javiana (12), Newport (6), Arechavaleta (5) and Heidelberg (5). Fifty-seven (85.1%) of 67 isolates exhibited resistance to one or more antimicrobial agents. Of eight antimicrobial agents tested, resistance was exhibited to streptomycin (80.6%), cephalothin (37.3%), neomycin (38.8%) and gentamicin (9.0%). All isolates were sensitive to ampicillin, norfloxacin, choramphenicol and sulphamethoxazole/trimethoprim. It was concluded that the isolation of the Salmonella spp. from non-diarrhoeic dogs could pose health hazard to their owners as most serotypes are known to be virulent. Furthermore, the prevalence of resistance to antimicrobial agents amongst the Salmonella isolates from these animals indicates susceptibility testing may influence chemotherapeutic choices when treating these isolates.     

水貂沙门氏菌的分离鉴定及药物敏感性分析

为指导临床合理用药并为治疗患病水貂提供依据,本试验对山东省某水貂养殖场送检的7只疑似患有沙门氏菌病的病死水貂的肝脏和脾脏样品进行细菌分离鉴定及药物敏感性分析,通过分离纯化方法从样品中分离菌株,并采用革兰氏染色、生化鉴定和PCR方法对分离菌株进行鉴定。运用K-B药敏法检测菌株对临床常用药物的敏感性,并通过PCR方法检测菌株耐药基因及Ⅰ类整合子的携带情况。结果显示,本试验分离得到的7株菌均为革兰氏阴性、短小的杆菌;生化反应检测显示,分离菌株葡萄糖、麦芽糖、甘露醇、MR试验、枸橼酸盐、硫化氢试验均表现为阳性,初步鉴定分离菌株为沙门氏菌;PCR产物测序结果进一步表明7株分离菌均为沙门氏菌;药敏试验结果显示,7株沙门氏菌对头孢曲松、左氧氟沙星、氟苯尼考和多黏菌素较敏感,对氨基糖苷类药物、四环素和氨苄西林表现为耐药;耐药基因检测结果显示,7株沙门氏菌共检测出8种耐药基因blaTEM-1、blaCTX-M-1G、aadA1、aac(3′)-Ⅳ、aac(3′)-Ⅱc、aph(4′)-Ⅰa、aph(3′)-Ⅶ和oqxAB,以及基因盒为aadA1、arr-3-aacA4和blaPSE-1的Ⅰ类整合子。综上可知,本试验在送检的7只患病水貂的肝脏和脾脏样品中分离到7株沙门氏菌,分离菌株均为耐药菌株,且主要表现为多重耐药现象;耐药基因呈多样性,且存在位于质粒上的耐药基因扩大了耐药基因的传播范围,增加了细菌的耐药性,为临床用药治疗带来困难。     

广东省部分地区禽源和猪源沙门菌血清型与耐药性及Ⅰ类整合子分析

为了解广东省禽场和猪场沙门菌的血清型和耐药性情况,本研究2015年从广东省多个养殖场共采集样品126份,分离出沙门菌24株,分离率为19.04%。采用Kauffmann-White法、Kirby-Bauer法和PCR方法对分离株进行了血清型鉴定、药敏试验和Ⅰ类整合子检测。血清型鉴定结果显示,24株沙门菌共鉴定出4种血清型,分别是鼠伤寒沙门菌(14株)、印第安纳沙门菌(8株)、科瓦利斯沙门菌(1株)和阿尔巴尼沙门菌(1株)。药敏试验结果显示,分离株对四环素(83.33%)、氨苄西林(70.83%)、磺胺异恶唑(70.83%)、萘啶酸(66.67%)、复方新诺明(58.33%)、卡那霉素(54.17%)、阿米卡星(54.17%)、庆大霉素(50.00%)的耐药率较高,有54.17%(13/24)的菌株对8种及8种以上抗菌药物耐药。Ⅰ类整合子检测结果显示,Ⅰ类整合酶阳性率为29.17%(7/24),整合酶阳性菌株中仅有1株扩增到携带耐药基因aadA2的基因盒。上述结果表明,广东省禽场和猪场沙门菌分离率较高,耐药情况严重,菌株的耐药性与其血清型和Ⅰ类整合子的携带有一定的相关性。     

Antimicrobial susceptibility of Salmonella isolates from the broiler chicken industry in Ontario.

Antibacterial drug resistance among 219 salmonella isolates recovered during 1974 from poultry and poultry environments at the various production stages of broiler chickens in three integrated Ontario companies are recorded. All isolates were susceptible to ampicillin, trimethroprim-sulfamethoxazole complex, furazolidone, cephaloridine and amoxicillin. A relative increase in resistance to tetracycline and streptomycin with an accompanying decrease in resistance to triple sulfa compound was recorded when compared to a previous investigation of avian salmonella isolates in Ontario. The percentage and patterns of antimicrobial resistance were comparable at the various stages of production. Resistance to tetracycline and streptomycin was the most common pattern found among both Salmonella typhimurium and other serotypes. A notably high prevalence of resistance was found among Salmonella enteritidis isolates including some isolates with R factors for chloramphenicol resistance. This latter finding is of particular concern because of the high prevalence of this serotype in poultry and in human salmonellosis.     

抗生素压力下不同血清型沙门氏菌耐药性研究

本研究旨在探讨不同血清型沙门氏菌在环丙沙星抗生素压力下突变频率及在耐药发展过程中靶位基因突变、外排泵及调控基因表达的差异。选取临床分离的印第安纳型、肠炎型和鼠伤寒型沙门氏菌的敏感菌株,在环丙沙星压力下诱导耐药突变,分别获得一系列不同程度的耐药突变株。分别检测不同血清型沙门氏菌突变株的突变频率、靶位基因喹诺酮耐药决定区(QRDRs)和外排泵调控基因ramR-ramA突变及外排泵相关基因的表达水平;同时检测了母株在羰基氰化物间氯苯腙(CCCP)存在情况下环丙沙星药物的蓄积浓度,以确定母株是否存在外排泵的作用。结果表明,在环丙沙星压力下,印第安纳型沙门氏菌较肠炎型和鼠伤寒型有更高的突变频率,易获得耐药株;印第安纳血清型菌株耐药性的获得主要是由于靶位基因gyrA发生单突变,协同外排泵外排作用增强而获得高水平耐药;肠炎型沙门氏菌耐药性获得主要是由于靶位基因gyrA发生83和87位双位点突变,并随着gyrB和parC基因的多位点同时突变而获得高水平耐药,耐药性的发展过程中没有外排泵作用参与;而鼠伤寒沙门氏菌在抗生素压力下不易发展成耐药菌,耐药性发生主要是由于靶位基因gyrB发生突变,而伴随parC基因突变及微弱的外排泵作用导致耐药水平增加。