Antibiotic resistance in Salmonella enterica subsp. enterica strains isolated in Poland from 1998 to 1999.

A total of 326 Salmonella enterica subsp. enterica strains representing 29 serotypes, isolated from human stool specimens during 1998-1999 in sanitary-epidemiological units in Poland were tested for antibiotic susceptibility by a standard disk diffusion method. The antibiotics used were ampicillin, cefotaxime, chloramphenicol, tetracycline, streptomycin, gentamicin, kanamycin, nalidixic acid, ciprofloxacin, furazolidone, cotrimoxazole, sulphonamides and trimethoprim. In addition, 201 strains belonging to the five most commonly isolated serotypes (S. Enteritidis, S. Typhimurium, S. Hadar, S. Infantis and S. Virchow) also had minimal inhibitory concentrations (MICs) determined for amoxycillin/clavulanic acid. Selected strains were screened for production of extended spectrum beta-lactamases (ESBLs). There were 49.4% of Salmonella enterica subsp. enterica strains resistant to two or more antibiotics, with the highest prevalence of multiple resistant strains among serotypes Typhimurium, Hadar and Virchow. Resistance to ampicillin, streptomycin, tetracycline, nalidixic acid, furazolidone and sulphonamides occurred most frequently. Over 93% of S. Virchow strains were resistant to furazolidone. No strains resistant to ciprofloxacin by disk-diffusion method were detected but 31.3% of isolates of the 201 strains representing the five most common serotypes had reduced ciprofloxacin susceptibility (MICs ranging 0.125-0.5 mg/l). One strain (S. Mbandaka) was resistant to cefotaxime and produced ESBL.     

Detection of integrons and antibiotic-resistance genes in Salmonella enterica serovar Typhimurium isolates with resistance to ampicillin and variable susceptibility to amoxicillin-clavulanate

We characterized 29 antimicrobial-resistant Salmonella enterica serovar Typhimurium strains, including four belonging to the monophasic variant 4,5,12:i:-, mostly isolated from infants. They were selected from 3230 strains isolated in the years 1990-2001 on the basis of resistance to ampicillin and variable susceptibility to the amoxicillin-clavulanate combination. Twenty-three strains were resistant to more than four antibiotics. All the strains carried the bla(TEM) gene and most were able to transfer this gene by conjugation. Sequencing of the gene from one of the amoxicillin-clavulanate-resistant strains allowed identification of the encoded beta-lactamase as TEM-1; all of these strains carried a second gene encoding beta-lactamase production, either pse-1 or oxa1. However, the association of bla(TEM) plus pse-1 genes did not always confer resistance to amoxicillin-clavulanate. The pse-1 gene, found in 17 strains, was located in the Salmonella Genomic Island-1 (SGI1), which carries two integrons and encodes multiple drug-resistance. None of the oxa1-bearing strains had the SGI1, yet this gene was found as part of an integron that also carried the aadA1 gene and was not plasmid-associated. Thirteen of the strains harbouring SGI1 belonged to the definitive phage type (DT) 104, and most of those remaining to DT104b and U302; particularly, strains carrying the oxa1-aadA1 integron belonged to the last two phage types. Pulsed field electrophoresis confirmed the clonal organization of DT104 strains, whereas U302 strains fell into different groups, depending on their resistance determinants.     

Antimicrobial susceptibility phenotypes, resistance determinants and DNA fingerprints of Salmonella enterica serotype Typhimurium isolated from bovine in Southern Japan

A longitudinal study was conducted in cattle to determine the antimicrobial resistance phenotypes, integron elements, resistance genes and pulsed-field gel electrophoresis fingerprints among Salmonella enterica serotype Typhimurium isolates. A total of 33 strains were isolated and categorised into Groups A, B and C during the period 1989-2004. Thirty-one strains (93.9%) showed resistance to ampicillin (A) encoded by bla(OXA-1), bla(TEM) and bla(PSE-1) genes; 84.8% showed resistance to chloramphenicol (C) encoded by floR and catA1; 97.0% were resistant both to streptomycin (S) and sulfamethoxazole (Su), the former encoded by aadA1 and aadA2; 100% were resistant to oxytetracycline (T) encoded by tetA, tetB and tetG; and 42.4% were resistant to kanamycin (Km) encoded by aphA1-Iab. Multidrug resistance types observed were ACSSuT-Km (n=13), ACSSuT (n=15), ASSuT (n=3) and SSuT (n=2). Class 1 integrons ranging from 1.0 kb to 1.9 kb were detected from 54.5% of isolates (18/33). Integrons were not detected initially (1989-1992), then during the 1993-1996 interval a high frequency of 1.0 kb and 1.2kb amplicons were detected and during 2000-2004 the amplicon size increased to 1.7 kb and 1.9 kb. We report evidence of additional integration of resistance gene cassettes as shown by integrons with increased size. Finally, group B strains showed banding patterns indistinguishable from S. Typhimurium DT104 reference strain, indicating that the DT104 lineage existed on the island since 1993.     

Antibiotic resistance, integrons and Salmonella genomic island 1 among non-typhoidal Salmonella serovars in The Netherlands

The objective of this study was to investigate the antimicrobial resistance patterns, integron characteristics and gene cassettes as well as the presence of Salmonella genomic island 1 (SGI1) in non-typhoidal Salmonella (NTS) isolates from human and animal origin. Epidemiologically unrelated Dutch NTS strains (n=237) originating from food-producing animals and human cases of salmonellosis were tested for their susceptibility to 15 antimicrobial agents. Resistance to 14 of these antimicrobials, including the third-generation cephalosporins, was detected. Resistance to sulphonamides, ampicillin, tetracycline, streptomycin, trimethoprim and nalidixic acid was common (>/=10% of the strains were resistant). Resistance against three or more antimicrobials was observed in 57 isolates. The same 237 strains were studied for the prevalence of class 1 integrons, their gene cassettes and the presence of SGI1. Thirty-six isolates (15.2%) carried class 1 integrons. These integrons had ten distinct profiles based on the size of the integron and restriction fragment length polymorphism analysis. Integrons were detected for the first time in serovars Indiana and Senftenberg. Multidrug resistance was strongly associated with the presence of class 1 integrons in which the aadA2, aadA1, bla(PSE-1), dfrA1, dfrA5, dfrA14 or sat genes were present, as determined by nucleotide sequence determination. The presence of gene cassettes or combinations of gene cassettes not previously found in integrons in Salmonella was observed. SGI1 or its variants (SGI-B, -C and -F) were present in 16 isolates belonging to either serovar Typhimurium, Derby or Albany. Regardless of whether the isolate was of human or animal origin, the same resistance phenotype, integron profile and SGI1 structure could be observed.     

Class 1 integrons and virulence genes in Salmonella enterica isolates from pork and humans

In this study, 183 Salmonella enterica isolates were characterised for integrons and virulence genes. Among the isolates, 46% were positive for intI1, but no isolates carried intI2 or intI3. Eighteen class 1 integrons (21%) contained resistance gene cassettes (i.e. dfrA1-orfC, dfrA12-aadA2, bla(PSE-1) and aadA2) and five class 1 integrons with the dfrA12-aadA2 array were conjugally transferable. Two Salmonella pork isolates of serotypes Albany and Kedougou possessed Salmonella genomic island 1 variants SGI1-G and SGI1-F, respectively. Four class 1 integrons contained an atypical 3'-CS linked to the qacH-sul3 domain, and three were not a sul type. Two novel GyrA mutations (Pro-45→Ser and Met-48→Ile) and three novel ParC mutations (Ser-5→Arg, Thr-31→Met and Leu-77→Arg) were identified in ciprofloxacin-resistant isolates. At least 90% of the Salmonella isolates contained pagC, prgH, sitC, sipB or spaN, whereas all isolates harboured invA, msgA, spiA and tolC.     

Assessment of factors contributing to changes in the incidence of antimicrobial drug resistance in Salmonella enterica serotypes Enteritidis and Typhimurium from humans in England and Wales in 2000, 2002 and 2004

An investigation into changes in the occurrence of antimicrobial resistance in Salmonella enterica serotypes Enteritidis and Typhimurium from human infection in England and Wales in 2000, 2002 and 2004 has shown that the incidence of strains of S. Enteritidis with resistance to nalidixic acid coupled with decreased susceptibility to ciprofloxacin has more than doubled between 2000 and 2004, whereas the overall levels of resistance in S. Typhimurium have fallen by ca. 25%. In relation to published data on veterinary sales of antimicrobials in the UK, the findings demonstrate that changes in the incidence of resistance do not correlate with changes in veterinary usage. For S. Enteritidis, important factors in the increased incidence of resistance were foreign travel and the consumption of imported foods contaminated with drug-resistant strains. For S. Typhimurium, the most important factor has been an overall decline in the occurrence of multiple drug-resistant S. Typhimurium definitive phage type 104. These studies have demonstrated that changes in the incidence of resistance in predominant salmonellas in humans in England and Wales from 2000 to 2004 are multifactorial. The findings also demonstrate that, in order to combat drug resistance in zoonotic salmonellas causing infections in humans, controls on the use of antibiotics in food animals analogous to those in operation in the UK should be implemented in countries that regularly import food into the UK.     

Salmonella bloodstream infections: report from the SENTRY Antimicrobial Surveillance Program (1997-2001)

Salmonella spp. are significant bloodstream pathogens and are routinely monitored for antimicrobial resistance by the SENTRY Antimicrobial Surveillance Program. Six hundred and one bloodstream infection (BSI) isolates of Salmonella spp., collected over a 5-year period (1997-2001) were tested for their susceptibility against 20 antimicrobial agents, comparing year and geographical region. Salmonella enterica serotype Typhi was the most frequently identified 'species' (43% of identified strains), although 'unspeciated' strains predominated overall (54.2%). The rank order for six selected drugs tested by their MIC(90) values and percentage susceptibility was: ceftriaxone (< or =0.25 mg/l; 99.5% susceptible)>ciprofloxacin (0.12 mg/l; 99.3%)> trimethoprim/sulphamethoxazole (< or =0.5 mg/l; 92.7%)>amoxycillin/clavulanate (16 mg/l; 89.7%)>ampicillin (>16 mg/l; 81.0%)>tetracycline (>8 mg/l; 79.4%). Most isolates remained highly susceptible to all 20 agents examined, with the exception of Salmonella Typhimurium (only 35.3% susceptible to tetracycline, 41.2% to ampicillin, and 61.8% to amoxycillin/clavulanate). DT104 resistance phenotypes were noted in 3.4 and nearly 60.0% of unspeciated Salmonella and S. Typhimurium, respectively. Unexpectedly, the highest overall susceptibility rates were recorded in Latin America. Fluoroquinolone resistance was observed and nalidixic acid screening MICs (< or =8 mg/l) predicted full susceptibility to ciprofloxacin. Five-year results from the SENTRY Program show no clear trend toward greater resistances in Salmonella spp. BSIs for the commonly used antimicrobial classes. With the exception of S. Typhimurium DT104, most Salmonella spp. remain highly susceptible to the tested antimicrobials that maybe utilized for Salmonella BSI.     

Emerging resistance in Salmonella enterica serotype Typhi in Hong Kong

A total of 182 Salmonella enterica serotype Typhi isolated from three hospitals in Hong Kong from 1986 to 1992 were tested for their susceptibility to 21 antimicrobial agents. Four percent or less were resistant to chloramphenicol, ampicillin, some of the cephalosporins, nalidixic acid, tetracycline and trimethoprim and 6% to 1024 mg/l sulfamethoxazole. All were susceptible to the aminoglycosides and the 4-quinolones. Nineteen isolates were resistant to at least 1, and up to 9, antibiotics. Of 8 chloramphenicolor multiply-resistant isolates studied, only 3 could transfer their resistances while resistance of one could only be mobilized. Four of 5 ampicillin-resistant strains produced a beta-lactamase of pI 5.5. Antibiotic resistances were mediated by plasmids of 106, 116 or 221 kb of incompatibility groups H, I1 and K. Three resistant isolates did not harbour any plasmid. A total of 43 (24%) S. Typhi harboured plasmids ranging in size from 4.3 to 221 kb. Plasmids of 106 kb and 8.5 kb were found in 17 and 10 isolates, respectively. Restriction enzyme digestion of these two plasmids showed that each could be differentiated into 3 types. Of 89 isolates that were phage typed, 38% were untypable, while 17% and 12% were of phage types E1 and A, respectively, and the rest belonged to 17 other types.     

Characterisation of Salmonella spp. mutants produced by exposure to various fluoroquinolones

We repeatedly exposed six Salmonella spp. strains of different serotypes (three susceptible to nalidixic acid and three resistant) to constant low concentrations of various fluoroquinolones with the aim of characterising the mutations that produce the first decrease in susceptibility to these agents. The fluoroquinolone-susceptibility of all the strains was reduced after repeated exposure to these agents. However, gyrA mutants were not always produced. Furthermore, the type of mutation produced and the time taken for it to appear varied depending on the initial resistance to nalidixic acid, the antibiotic used and the serotype involved. Therefore, we believe that the initial decrease in quinolone-susceptibility is due to various mechanisms and, in many cases, is not caused by mutations in the gyrA gene     

High prevalence of plasmid-mediated quinolone resistance determinant aac(6')-Ib-cr amongst Salmonella enterica serotype Typhimurium isolates from hospitalised paediatric patients with diarrhoea in China

In this study, the antimicrobial susceptibilities and prevalence of plasmid-mediated quinolone resistance determinants amongst Salmonella enterica serotype Typhimurium isolates from hospitalised paediatric patients with diarrhoea in China were investigated. In total, 40 (64.5%) of 62 S. Typhimurium isolates were resistant to ciprofloxacin (minimum inhibitory concentration ≥0.5 μg/mL), comprising 28 isolates with low-level resistance and 12 isolates with high-level resistance. All ciprofloxacin-resistant isolates were multiresistant to other antimicrobial agents. Four pulsed-field gel electrophoresis (PFGE) clusters were found amongst the 40 ciprofloxacin-resistant isolates, amongst which PFGE clusters A, B, E and D accounted for 7, 4, 1 and 28 isolates, respectively. Two isolates with high-level ciprofloxacin resistance had two mutations in the quinolone resistance-determining regions (QRDRs) of gyrA and parC. The remaining ciprofloxacin-resistant isolates had only one mutation in the QRDR of gyrA. All 62 S. Typhimurium isolates were negative for qnr genes and qepA and 23 (37.1%) of the isolates were positive for aac(6')-Ib-cr. Nineteen isolates harbouring aac(6')-Ib-cr belonged to PFGE cluster D. A high prevalence of ciprofloxacin resistance and aac(6')-Ib-cr was found amongst S. Typhimurium isolates in China from hospitalised paediatric patients with diarrhoea not receiving quinolones. A single mutation in the QRDR of gyrA as well as production of AAC(6')-Ib-cr contributed to ciprofloxacin resistance. Clonal spread was responsible for the dissemination of aac(6')-Ib-cr amongst S. Typhimurium isolates.     

Molecular characterisation of multidrug-resistant Salmonella enterica serotype Infantis from humans, animals and the environment in Italy

During 2005–2006, Salmonella enterica serotype Infantis strains isolated from human and non-human sources and resistant to ampicillin (A), chloramphenicol (C), streptomycin (S), sulphonamide (Su), tetracycline (T), kanamycin (K) and trimethoprim/sulfamethoxazole (Sxt) emerged in Italy. The aim of this study was to analyse the molecular basis of antibiotic resistance and to evaluate the clonal origin of multiresistant S. Infantis strains isolated from different sources. Seventy S. Infantis strains, susceptible or resistant to antimicrobial drugs, were chosen for this study. Polymerase chain reaction (PCR) and conjugation experiments were performed to identify and localise the resistance genes in multidrug-resistant strains. PCR-based replicon typing was carried out for characterisation of conjugative plasmids. All strains were tested by pulsed-field gel electrophoresis (PFGE) according to the PulseNet protocol, and cluster analysis was performed using BioNumerics software. Strains with resistance (R)-type ACSSuTKSxt harboured bla_TEM-1, strA-B, sul2, tet(B), catA1 and aphA-1 resistance genes as well as a 2.2-kb class 1 integron containing folA, catB3, aadA4 and sul1 gene cassettes. A unique plasmid, belonging to the HI1 incompatibility group, harboured all the resistance genes. Cluster analysis showed that all ACSSuTKSxt-resistant strains belonged to a large cluster (A) with >90% genetic similarity. The presence of a plasmid harbouring all the resistance gene cassettes as well as molecular typing by PFGE demonstrated the circulation of a cluster of S. Infantis R-type ACSSuTKSxt during 2005–2006 in Italy. The presence of a plasmid conferring multidrug resistance could have facilitated the spread of a group of similar isolates through a variety of sources.     

Molecular epidemiology of antimicrobial resistance among Salmonella enterica serovar Infantis from poultry in Kagoshima, Japan

Antimicrobial susceptibility and resistance genes of 135 strains of Salmonella enterica serovar Infantis isolated from poultry in Kagoshima were examined. One strain (0.7%) was resistant to ampicillin (A), 97% to streptomycin (S), 95.6% to sulphamethoxazole (Su), 96.3% to oxytetracycline (T), 11.1% to kanamycin (Km) and 36.3% to ofloxacin (O). Multiresistant phenotypes identified were ASSuT-Km, SSuT-Km, SSuT-O and SSuT. Class 1 integrons were detected in 94.8% of isolates. Approximately 89% of oxytetracycline-resistant strains carried the tetA gene and all of the 131 streptomycin-resistant isolates carried the aadA1a gene. Forty-percent of kanamycin-resistant isolates carried the aphA1-Iab gene. All isolates were susceptible to chloramphenicol. Recognition of TEM-type beta-lactamase in a S. Infantis strain from chickens is a recent rare finding in Japan.     

辽宁地区沙门菌整合子与耐药相关性研究

摘要：目的 及时掌握辽宁地区沙门菌整合子的分布以及对常用抗菌药物的耐药情况,获取沙门菌整合子与耐药性的相关性,从而为临床用药及治疗提供指导。方法 本文对来源于食品以及病患的149株沙门菌,利用PCR扩增的方法,进行整合子类别的筛选,并将扩增的整合子基因盒进行基因测序,同时通过药敏板测定(耐药性实验)对沙门菌与15种临床常用抗菌药物的耐药相关性进行研究。结果 149株沙门菌中未发现第II类、第III类整合子,检出第I类整合子的菌株50株,I类整合子阳性率为33.6%。50株整合子阳性菌株中25株携带耐药基因盒,片段范围从1500~1800 bp。测序结果表明,其中22株整合子携带dfrA17-aadA5基因盒,2株携带dfrA12-aadA2基因盒,1株首次检出罕见耐药基因盒linG。根据整合子携带情况不同,对15种抗菌药物的耐药率进行对比分析,结果显示整合子阳性菌对9种抗菌药物的耐药率显著高于整合子阴性菌(P<0.01),分别为氨苄西林、四环素、氯霉素、头孢噻肟、头孢唑林、庆大霉素、复方磺胺甲恶唑、阿奇霉素和环丙沙星。辽宁地区沙门菌多重耐药率达50.3%。结论 I类整合子在沙门菌中分布广泛,抗性基因表型与耐药结果相一致,整合子的携带与沙门菌多重耐药率高度相关。沙门菌对亚胺培南和头孢西丁保持高敏感率,可以用于对常规抗菌药物耐药的沙门菌的治疗。     

Prevalence, distribution and characterisation of ceftiofur resistance in Salmonella enterica isolated from animals in the USA from 1999 to 2003

Third-generation cephalosporin (3GC) antimicrobials are the drugs of choice for treatment of salmonellosis in children. Salmonella isolated in the USA are assayed by the National Antimicrobial Resistance Monitoring System (NARMS) for resistance to antimicrobials including first-, second- and third-generation cephalosporins. From 1999 to 2003, 34,411 Salmonella were isolated from animals in the USA, of which 10.9% were found to be resistant to ceftiofur, a 3GC used in animals, whilst only 0.3% were resistant to ceftriaxone, a 3GC used in human medicine. Ceftiofur resistance rose from 4.0% in 1999 to 18.8% in 2003. Isolates from diagnostic laboratories had higher levels of resistance (18.5%), whereas levels in isolates from on-farm (3.4%) and slaughter (7.1%) sources were lower. Animals with a higher than average proportion of resistant Salmonella included cattle (17.6%), horses (19.2%) and dogs (20.8%). Levels in turkeys (6.8%), chickens (7.1%), eggs (3.6%) and swine (4.6%) were lower. Resistance varied between Salmonella serotypes. A few serotypes had significantly high levels, e.g. S. Newport was 70.4% ceftiofur resistant. Resistance was predominantly associated with bla(CMY-2)-encoding plasmids. These data suggest that the acquisition of resistance plasmids and the spread of specific serotypes harbouring these plasmids are driving the observed resistance to ceftiofur in Salmonella animal isolates.     

Transferable antibiotic resistance in Escherichia coli isolated from healthy Nigerian school children

Three hundred and ninety-six E. coli isolates obtained from apparently healthy school children in Ile-Ife, Nigeria, were tested for their susceptibility to 11 different antibiotics. Of these, only gentamicin, cefotaxime and nalidixic acid were found to have significant in vitro activity against most of the isolates. The incidence of antibiotic resistances encountered varied between 24% for trimethoprim and 55.5% for the sulphonamide. It was further observed that 47.5% of the isolates were identified as being multiply resistant, since they were simultaneously resistant to at least three different antibiotics. The 86 trimethoprim-resistant isolates tested were found to be able to transfer this resistance trait together with resistance genes of to other antibiotics, into a plamidless strain of E. coli by conjugation. Seventy-seven of the trimethoprim-resistant isolates were also found to be classifiable into the types of dihydrofolate reductases responsible for the observed resistance on the basis of hybridization experiments. The results of this study indicate that there is a large reservoir of antibiotic resistances within the community, and that the resistance genes were easily transferable to other strains even without direct exposure to antibiotics.     

Predictive value of nalidixic acid resistance for detecting salmonellae with decreased ciprofloxacin susceptibility

Seventy-three Salmonella isolates classified as ciprofloxacin susceptible when using the criteria of the National Committee for Clinical Laboratory Standards were studied for nalidixic acid (NA) resistance. The aim of the study was to determine the predictive value of nalidixic acid resistance in screening for decreased ciprofloxacin susceptibility. We observed that isolates with decreased ciprofloxacin susceptibility were all resistant to nalidixic acid. Identification of nalidixic acid resistance by the disk diffusion method provided 100% sensitivity and a specificity of 98.4% in strains with minimum inhibitory concentrations (MICs) >0.008 mg/l.     

布伦登卢普沙门菌耐药性与毒力基因分析

目的 研究临床分离的非伤寒沙门菌布伦登卢普血清型（布伦登卢普沙门菌）对抗菌药物的耐药性及其 携带的毒力基因特征。方法 收集 2012—2014 年每年 4—10 月天津市两家教学医院肠道门诊急性腹泻患者的临 床资料, 将急性腹泻患者粪便标本进行沙门菌分离培养、 生化及 PCR 鉴定、 血清学分型, 对得到的布伦登卢普沙门菌 进行抗菌药物敏感性检测、 PCR 扩增沙门菌毒力岛 （SPI） 1~5 的代表性基因和 SPI 的调节基因。结果 3 年共检测到 非重复非伤寒沙门菌 153 株, 其中 8 株 （5.23%） 为布伦登卢普沙门菌。8 株 invA-PCR 鉴定均呈阳性, 对萘啶酸耐药 率 100%, 对环丙沙星和左氧氟沙星中介耐药率 100%, 对其余检测的抗菌药物敏感; 8 株均检测到了 SPI 1~5 代表性 基因和 SPI 调节基因 （sitC、 hilA、 sseL、 sifA、 mgtC、 siiE、 sopB 和 phoP）。结论 天津地区布伦登卢普沙门菌临床株对氟 喹诺酮耐药并携带 SPI 1~5 毒力基因与调节基因, 对公众健康构成潜在威胁, 应持续开展相关监测与研究。     

人苍白杆菌的分离及耐药性分析

目的:了解人苍白杆菌在我院的分离情况及耐药性.方法:统计分析近4年分离到的83株人苍白杆菌耐药情况.结果:人苍白杆菌均分离自肝移植患者的血液标本,对β-内酰胺类抗生素均高度耐药,对哌拉西林/三唑巴坦、头孢哌酮/舒巴坦亦高度耐药,对其他抗菌药物有较好的敏感性,依次为环丙沙星(100%)、左旋氧氟沙星(100%)、亚胺培南(92.7%)、萘啶酸(92.0%)、奈替米星(91.7%)、妥布霉素(90.0%).结论:人苍白杆菌对β-内酰胺类抗生素耐药率高,治疗应首选喹诺酮类抗生素、亚胺培南.     

2015-2017年中山市某医院沙门菌的药敏分析及肠毒素基因检测

目的 研究中山市西北部区域沙门菌感染患者的流行病学特征、耐药特点及其相关肠毒素基因型。方法 2015年1月-2017年12月，我院从4019例腹泻患者的粪便标本中共分离出沙门菌108株，进行血清分型及药物敏感试验，同时采用PCR方法检测其肠毒素基因(spvA、spvB、rck)。结果 108株沙门菌可分为17个血清型，以鼠伤寒沙门菌和斯坦利沙门菌为主，分别占42.6%(46/108)和15.7%(17/108)，2015年分别检出伤寒沙门菌、乙型副伤寒沙门菌和丙型副伤寒沙门菌各一株；108株沙门菌对氨苄西林(61.11%)和氨苄西林/舒巴坦(49.07%)耐药率最高，未发现对亚胺培南及哌拉西林/三唑巴坦的耐药菌株；在108株沙门菌中，所有菌株均含有spvA基因，34株为spvB阳性，28株为rck阳性，spvB基因阳性患者其高热、便血的比率显著高于spvB阴性患者(χ2=4.185, P<0.05; χ2=6.13, P<0.05)；rck基因阳性患者其高热、便血的比率显著高于rck阴性患者(χ2=5.274, P<0.05, χ2=8.887，P<0.05)。结论 本地区沙门菌感染患者以鼠伤寒沙门菌和斯坦利沙门菌为主，高发季节集中在夏秋两季，沙门菌株耐药率较高。沙门菌感染患者高热及便血的发生率与spvB基因、rck基因的检出具有明显相关性。