Vibrio vulnificus, a major human-pathogenic Vibrio species, causes foodborne or wound-related infections with a globally rising incidence. The study aimed to characterize the molecular characteristics of V. vulnificus to support the prevention, control, and clinical treatment of its infection. A total of 63 V. vulnificus isolates from seafood and patients in Wenzhou were subjected to sequencing, bioinformatic analysis, and antimicrobial susceptibility testing. Single nucleotide polymorphism and multilocus sequence typing analysis of 100 isolates (63 from this study, 37 from the NCBI database) were performed to assess genetic characteristics. Nine key virulence genes, associated with adhesion, RTX toxin, and T6SS, and eight antimicrobial resistant genes (ARGs) were identified. All isolates were resistant to colistin (CT), with 74.6%, 58.7%, and 3.2% resistance to streptomycin, amikacin, and nalidixic acid, respectively, and were susceptible to 12 other tested antimicrobials. V. vulnificus infection cases in this study showed a significant demographic skew toward males aged ≥50 years. The isolates exhibited genetic diversity while sharing virulence genes and ARGs. In silico detected ARGs could not accurately predict in vitro antimicrobial resistance phenotypes, so extreme caution is required when using ARGs detection results to guide clinical anti-infective medication. This study provides basic genomic and phenotypic data of local V. vulnificus isolates, which may serve as a reference for local surveillance and clinical empirical treatment of V. vulnificus infection.

ObjectiveTo investigate the contamination of Listeria monocytogenes （L. monocytogenes） in ready-to-eat （RTE） foods in Wenzhou City， and characterize the antimicrobial resistance， virulence gene profiles， and genetic diversity of the isolates.MethodsL. monocytogenes strains were isolated and identified according to GB 4789.30—2016. Antimicrobial susceptibility testing was performed using the broth microdilution method. Virulence genes， multilocus sequence typing （MLST）， and core genome multilocus sequence typing （cgMLST） were analyzed based on whole-genome sequencing.ResultsA total of 91 strains of L. monocytogenes were isolated from 1 285 samples across 5 categories of RTE foods， with a detection rate of 7.08% （91/1 285）. Among these， the detection rate of Chinese cold dishes was the highest （14.34%， 36/251）， followed by cooked meat products （9.62%，15/156）. The susceptibility rates of the isolates to each of the nine antimicrobial agents ranged from 94.51% to 100.00%. The isolates comprised two lineages （Ⅰ and Ⅱ）， 15 STs， and 14 CCs. The predominant serogroups were Ⅱa （47.25%，43/91） and Ⅱb （32.97%，30/91）. The CC87/ST87 （21.98%，20/91）， CC121/ST121 （16.48%，15/91）， and CC8/ST8 （13.19%，12/91） were the dominant sequence types. All isolates carried virulence genes associated with LIPI-1（Listeria Pathogenicity Island 1， LIPI-1） and LIPI-2， 19.78% （18/91） harbored the LIPI-3， while the LIPI-4 was exclusive to strains of CC619/ST3004 and CC87/ST87.ConclusionL. monocytogenes is prevalent to a certain extent in RTE foods in Wenzhou City. The isolates exhibited low antimicrobial resistance， displayed high genetic diversity， and possessed pathogenic potential. Strengthening surveillance of highly virulent clones is essential for preventing the foodborne disease outbreaks.

BACKGROUND:Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. The study aims to investigate the prevalence, antimicrobial resistance, and genotyping of diarrheagenic Escherichia coli (DEC) in foodborne diarrhea cases in Wenzhou City in 2023, providing a scientific foundation for the monitoring and prevention of bacterial foodborne diseases. METHOD:Fecal samples from patients with diarrhea were collected from four sentinel hospitals for the isolation of DEC. The pathogenic types of DEC were identified using fluorescence quantitative polymerase chain reaction. Antimicrobial susceptibility testing was performed by broth microdilution, while whole-genome sequencing was utilized for genotyping. Clustering analysis based on the EnteroBase database was conducted to assess the genetic similarity of the strains. RESULTS:Among 2591 fecal samples tested, 90 were positive for DEC, resulting in a detection rate of 3.47% (90/2591). The majority of DEC isolates were enterotoxigenic E. coli (ETEC) and enteroaggregative E. coli (EAEC), accounting for 87.78% (79/90) of the total. DEC detection showed a seasonal pattern, with the highest positivity observed in individuals aged 20-39 years. The genotyping of the most prevalent virulence genes in ETEC was estIa/estIb (57.50%, 23/40), while aggR (23.08%) was most common in EAEC. Genotyping revealed high genetic polymorphism among DEC strains, with HC1100_13 being the predominant clone. The prevalence of the resistance gene blaEC was 96.67%. The highest drug resistance rate was observed in ampicillin (68.89%), followed by nalidixic acid (51.11%), and the multidrug resistance rate was 65.56%. CONCLUSION:ETEC and EAEC were the most common DEC strains detected in Wenzhou in 2023. These strains exhibited significant genetic diversity and displayed considerable antimicrobial and multidrug resistance, highlighting the need for enhanced monitoring and intervention strategies.

Yersinia enterocolitica is a significant foodborne pathogen causing gastrointestinal illnesses worldwide. This study investigates the prevalence and genomic characteristics of Y. enterocolitica to assess potential health risks in southeastern China, a region lacking mandatory yersiniosis monitoring. From 2939 samples collected between 2008 and 2022, 105 isolates were recovered. The highest prevalence was found in rodents (8.1

ObjectiveTo understand and master the infection status and molecular epidemiological characteristics of Cronobacter spp. in diarrhea patients in Wenzhou， and to provide a scientific basis for the prevention and control of foodborne diseases caused by Cronobacter spp. in this region.MethodsFrom 2013 to 2024， stool samples were collected from diarrhea patients with foodborne diseases in Wenzhou and tested for Cronobacter spp. Isolated Cronobacter strains underwent species identification， molecular serotyping， and whole-genome sequencing. Bioinformatics analyses were performed to assess genetic relatedness through cluster analysis， as well as to detect the presence of virulence-associated genes and antimicrobial resistance genes.ResultsA total 21 strains of Cronobacter spp. were detected in 1 816 samples， with a total isolation rate of 1.16%. In terms age distribution， the proportion of patients aged 18-60 years was 38.10%， and the proportion of patients under 1 year old was 33.33%. In terms of seasonal distribution， the detection rate in spring accounted for 38.10%， and that in summer accounted for 33.33%. Among the isolated strains， there were 14 strains of Cronobacter sakazakii， accounting for 66.67% of the total number of strains. Cronobacter sakazakii could be divided into 4 serotypes and 1 untyped strain， among which Csak O1 was the main serotype； Cronobacter malonaticus was divided into 2 serotypes， with Cmal O2 as the main serotype. After identification， the 21 strains of Cronobacter spp. were divided into 10 ST types and 8 clonal complexes （CC）， among which CC7 and CC4 were the main clonal complexes， and ST4 and ST201 were the main ST types. The gene annotation results of the 21 strains showed that all of them carried 17 genes related to motility， adhesion and invasiveness， etc. In addition， a total of 15 drug resistance genes were screened out， and most of the strains carried 11-14 drug resistance genes.ConclusionIn cases of foodborne diarrhea caused by Cronobacter spp. in Wenzhou， attention should be focused on Cronobacter spp. infections in infants. Csak O1 and Cmal O1 are the main serotypes， CC4 and CC7 are the main clonal complexes， and ST4 and ST201 are the main ST types.

The infection status and etiological analysis of Aeromonas spp. from foodborne diarrhea patients in Wenzhou were carried out to provide the etiological basis for healthy diet and clinical treatment. Aeromonas isolates (n = 41) collected from foodborne diarrhea patients were identified using the automatic bacteriologic analyzer and mass spectrometer. Species identification, multilocus sequence typing, prediction of virulence genes, and antimicrobial resistance genes were analyzed by the data of whole genome sequencing. The antibiotic resistance of these isolates was determined using miniaturization of the broth dilution susceptibility test. A total of 1829 stool samples of diarrhea patients were collected, and the detection rate of Aeromonas spp. was 2.24% (41/1829). Moreover, Aeromonas spp. are more easily detected in warmer months (from June to August), which were identified as follows: A. veronii (53.66%, 22/41), A. caviae (21.95%, 9/41), A. hydrophila (9.76%, 4/41), A. dhakensis (4.88%, 2/41), A. rivipollensis (4.88%, 2/41), A. enteropelogenes (2.44%, 1/41), and A. media (2.44%, 1/41). All strains can be divided into 38 sequence types, 31 of which were novel, suggesting that Aeromonas spp. had high genetic diversity, multiple clones, and various sources in diarrhea patients. High number of genetic diversity and resistance were found in the Aeromonas isolates. In addition, the category distribution of the virulence genes was significantly different among the seven species of Aeromonas. Aeromonas spp. had different degrees of resistance to antibiotics, and tetracycline was the most serious, with a resistance rate of 27%. What's more, for some antimicrobial classes in silico antimicrobial resistance gene detection was highly correlated with phenotypic antimicrobial resistance patterns with an overall sensitivity of 93.3% and a specificity of 66.7%. The findings from this research highlighted the importance for development of prevention and control strategies to reduce the risk of foodborne diarrhea caused by Aeromonas spp.

OBJECTIVES:To investigate cases of five Campylobacter jejuni outbreaks and describe laboratory characteristics of these infections.METHODS:Whole-genome sequencing and conventional methods were combined to thoroughly investigate the outbreaks, and data of contemporaneous sporadic cases was included for comparison.RESULTS:Seven sequence types (STs) of C. jejuni caused 83 cases, including ST9079 which recurred across 2 years. Trace-back investigation could not identify any food items of infection but detected identical campylobacters from food contacts. Phylogenetic analysis unveiled genetic closeness between outbreak strains and some concurrent sporadic strains, indicating local campylobacteriosis may not be wholly sporadic but rather a series of linked cases. Virulence genes disclosed species/case-specific signatures to differentiate outbreaks from truly non-outbreak strains. Resistance to fluoroquinolones and/or macrolides was prevalent (90.8%, 108/119), with a noteworthy portion exhibiting multidrug resistance (31.1%, 37/119). Five types of plasmids were harbored among outbreak isolates, of which one plasmid harboring anti-stress and resistant genes was rarely found in C. jejuni.CONCLUSIONS:This is the first reported sequential outbreak of C. jejuni in China. Our observations help to define the genomic landscape and antimicrobial resistance patterns of Campylobacter, emphasizing the need for a broader 'One Health' perspective to combat the threats posed by campylobacteriosis.

目的 了解温州地区食源性腹泻患者副溶血性弧菌流行情况及分子分型特征,为预防食源性疾病提供科学依据.方法 对分离自腹泻患者中的副溶血性弧菌进行流行情况分析,同时对分离菌株开展血清学分型和药敏试验,进-步通过脉冲肠凝胶电泳(PFGE)分型技术分析菌株之间的遗传关系.结果 温州地区食源性疾病腹泻患者中,分离出446株副溶血性弧菌,检出率为6.79％;共鉴定出17个血清型,其中以O10 ∶K4(80.49％)为优势型别;以青壮年为多;夏秋季易感,8月-11月是高峰期,具有明显的季节性;122株副溶血性弧菌可分成28种PFGE型,大部分O10 ∶K4血清型聚集成簇;对头孢唑啉普遍耐药.结论 温州地区副溶血性弧菌监测具有明显的流行特征,应该继续加强食源性疾病监测,特别要关注新的O10 ∶ K4血清型引起大流行的可能,更要进一步提高食品安全隐患的早期识别、预警与防控能力.

目的 了解2020年—2021年温州市畜肉中小肠结肠炎耶尔森菌的污染现状及病原特征.方法 对2020年—2021年温州市食品安全风险监测中的畜肉样本进行小肠结肠炎耶尔森菌的分离鉴定、血清分型、生物分型、毒力基因检测、耐药性分析和脉冲场凝胶电泳(PFGE)分子分型.结果 356份样本共检出小肠结肠炎耶尔森菌31株,检出率为8.71％.分离菌株血清型以O∶5型为主,生物型以1A型为主.检出1株4/O∶3型菌株携带毒力基因ail、ystA、yadA、virF,其余菌型菌株仅携带ystB或不携带任何毒力基因.分离株对头孢西丁、磺胺异恶唑耐药率最高,为32.26％,多重耐药株有4株,占12.90％.31株分离株经PFGE分型,共获得31种带型.结论 小肠结肠炎耶尔森菌是温州市畜肉中的潜在污染源,菌株耐药率处于较低水平但存在多重耐药株,PFGE带型呈多态性分布.

ObjectiveTo analyze the epidemiological characteristics of Salmonella infection in Wenzhou City from 2006 to 2021 and provide a scientific basis for the prevention and control of Salmonella infection.MethodsSalmonella was identified and serotyped， and the epidemiological and etiological characteristics were analyzed.ResultsFrom 2006 to 2021， 1 232 strains of Salmonella were isolated from 42 300 cases of diarrhea caused by foodborne diseases in Wenzhou City， with a total isolation rate of 2.91%， covering 90 serotypes （14 flora）， of which the floras were mainly O： 4（B）， O： 9（D1）， O： 3，10（E1）， O： 8（C2-C3）， and O： 7 （C1）； Salmonella typhimurium， Salmonella enteritidis， Salmonella London， and Salmonella derby were the main serotypes； 18-60 years old， over 61 years old and under 2 years old infants were the main infection group； Salmonella was susceptible mainly in spring， summer and autumn with obvious seasonality and the peak period of detection of foodborne Salmonella was from May to November.ConclusionSalmonella infection in Wenzhou City has obvious epidemiological characteristics in terms of seasonal and population distribution； therefore， we should continue to strengthen the surveillance of food-borne diseases， and further improve the ability of early identification， early warning， prevention， and control of hidden dangers in food safety.

Increasing human salmonellosis caused by Salmonella enterica serovar Kentucky and London has raised serious concerns. To better understand possible health risks, insights were provided into specific genetic traits and antimicrobial resistance of 88 representative isolates from human and food sources in Zhejiang Province, China, during 2016-2021. Phylogenomic analysis revealed consistent clustering of isolates into the respective serovar or sequence types, and identified plausible interhost transmission via distinct routes. Each serovar exhibited remarkable diversity in host range and disease-causing potential by cgMLST analyses, and approximately half (48.6%, 17/35) of the food isolates were phylogenetically indistinguishable to those of clinical isolates in the same region. S. London and S. Kentucky harbored serovar-specific virulence genes contributing to their functions in pathogenesis. The overall resistance genotypes correlated with 97.7% sensitivity and 60.2% specificity to the identified phenotypes. Resistance to ciprofloxacin, cefazolin, tetracycline, ampicillin, azithromycin, chloramphenicol, as well as multidrug resistance, was common. High-level dual resistance to ciprofloxacin and cephalosporins in S. Kentucky ST198 isolates highlights evolving threats of antibiotic resistance. These findings underscored the necessity for the development of effective strategies to mitigate the risk of food contamination by Salmonella host-restricted serovars.

ObjectiveTo investigate the distribution and molecular typing characters of Yersinia enterocolitica in food in Wenzhou.MethodsAfter pre-enrichment of samples at 4 ℃， the selective media was used for the isolation and identification of Yersinia enterocolitica from food. The biotype， serotype， virulence genotype， drug resistance and pulsed field gel electrophoresis， （PFGE） molecular typing of the isolated strains were analyzed.ResultsAmong 676 samples in 6 categories， 69 Yersinia enterocolitica strains were isolated from 68 samples， with a positive rate of 10.1% （68/676）. The detection rate of prepared meat products was the highest （20.5%， 9/44）， followed by quick-frozen food （17.2%， 11/64）. Biotype 1A accounted for 95.7% （66/69） of the isolates， and the predominant bioserotype was 1A/O∶5 （29.0%）， followed by 1A/O∶8（14.5%）. 88.4% （61/69） of the strains only harbored ystB gene. Particularly， there was a bioserotype 4/O∶3 strain carried the virulence gene of ail， ystA， yadA and virF. The sensitivity rates of the isolates to 14 kinds of antibiotics were over 94%. Thirty two serotyped strains were divided into 29 PFGE patterns.ConclusionFood was contaminated by Yersinia enterocolitica to some degree in Wenzhou， and the pathogenic strain was detected. The antibiotic resistance rate of Yersinia enterocolitica was at a low level， and PFGE suggested highly genetic polymorphism.

目的 了解温州市弯曲菌引起腹泻的流行病学特点,掌握弯曲菌的耐药状况、分子型别特征.方法 在2017至2019年间对2家温州市区哨点医院的腹泻病例进行流行病学调查,并采集粪便标本进行弯曲菌的分离培养和常规生化鉴定,采用聚合酶链反应(Polymerase Chain Reaction,PCR)进一步鉴定,同时进行药敏试验、多位点序列分型(Multilocus-sequence typing,MLST)研究.结果 909例腹泻病例弯曲菌检出率为10.2％(93/909),空肠弯曲菌和结肠弯曲菌阳性率分别为8.9％(81/909)和1.3％(12/909).6个年龄组间及不同季节的弯曲菌阳性率差异无统计学意义(x2年龄=2.09,P＞0.05;x2季节=0.468,P＞0.05).93株弯曲菌对11种抗菌药物共产生了22种耐药谱,耐萘啶酸(Nalidixic acid,NAL)-环丙沙星(Ciprofloxacin,CIP)-四环素(Tetracycline,TET)谱型最多,占38.7％(36/93).空肠弯曲菌和结肠弯曲菌多重耐药率(耐3种以上抗生素)分别为42.0％(34/81)、50.0％ (6/12).MLST分型结果显示本地分离株中,空肠弯曲菌被分成54种ST型,含15个克隆群,最多的克隆群为ST45CC,占11.1％(9/81),结肠弯曲菌分为8种ST型,主要的克隆群为ST828CC,占83.3％(10/12).本研究共发现16个新的ST型.结论 温州市食源性腹泻病例中弯曲菌已成为主要病原,且呈现很高的多重耐药性,在遗传特征上表现为遗传多样性.

目的 了解温州市农贸市场禽肉中空肠弯曲菌污染现状及耐药情况,为禽肉类食品安全风险评估、弯曲菌病防控和临床用药提供依据.方法 于2018年2月-2019年10月从温州市鹿城区、龙湾区、瓯海区、瑞安市、苍南县、平阳县和文成县7个县(市、区)的农贸市场采集禽肉样品.采用双孔滤膜法检测空肠弯曲菌,并进行药敏试验.结果 共采集样品200份,检出空肠弯曲菌66份,检出率为33.00％.鸡肉中检出空肠弯曲菌45份,检出率为34.09％;鸭肉中检出空肠弯曲菌21份,检出率为30.88％,不同样品空肠弯曲菌检出率差异无统计学意义(P＞0.05).鹿城区、平阳县和苍南县空肠弯曲菌检出率最高,均为35.00％,不同采样地区空肠弯曲菌检出率差异无统计学意义(P＞0.05).多重耐药38株,多重耐药率为57.58％,以萘啶酸、四环素和环丙沙星耐药率较高,分别为84.85％、83.33％和80.30％.结论 温州市农贸市场禽肉空肠弯曲菌污染较重,且对萘啶酸、四环素、环丙沙星等多种抗生素有显著耐药性.

目的 对碳青霉烯类抗生素耐药的肺炎克雷伯菌进行耐药分析及分子分型,为临床治疗提供病原学依据.方法 收集定点医院2016年8月-2018年12月临床标本中分离的耐碳青霉烯类肺炎克雷伯菌,采用VITEK 2 Compact进行细菌鉴定及药敏试验,标准纸片扩散法作为补充,碳青霉烯酶相关基因通过PCR扩增和产物测序确定,用脉冲场凝胶电泳(PFGE)进行分子分型并分析菌株的同源性.结果 71株肺炎克雷伯菌均耐15种药物以上,多重耐药率为100％.其中67株菌产超广谱β-内酰胺酶(94.4％),59株携带碳青霉烯酶blaKPC-2基因(80.3％).经PFGE图谱分析分为49个PFGE型,其中以WZFK001型最多,占9.8％.结论 产KPC-2型碳青霉烯酶是该院肺炎克雷伯菌碳青霉烯类抗生素耐药的主要原因,产超广谱β-内酰胺酶是β-内酰胺酶类抗生素耐药的主要机制.ICU等病房存在高度同源性的耐碳青霉烯肺炎克雷伯菌流行,应加强这些病房的院感管理,控制多重耐药菌的传播和流行.

目的 分析2014年-2018年温州市伦敦沙门菌和德尔卑沙门菌临床分离株耐药性和分子型别特征.方法 对2014年-2018年食源性疾病腹泻患者分离得到的25株伦敦沙门菌和20株德尔卑沙门菌采用微量肉汤稀释法进行15种抗菌药物的敏感试验,并运用脉冲场凝胶电泳(pulsed-field gel electrophoresis,PFGE)进行分子分型.结果 实验菌株除对3种抗生素敏感外,对其余12种抗生素均有不同程度的耐药,有34株多重耐药(占75.56％).四环素耐药率最高(占91.11％);25株伦敦沙门菌用Xba Ⅰ酶切获得16种带型,相似度为66.5％～100％.20株德尔卑沙门菌用Xba Ⅰ酶切获得10种带型,相似度为75.4％～100％.结论 温州市食源性沙门菌耐药状况严重,PFGE带型呈现出多样性的同时又具有较显著的优势带型特点.部分带型与其对应的耐药谱具有一定的关联性.

Campylobacteris a zoonotic pathogen that causes foodborne diarrheal illness globally. To better understand health risks in Southeastern China,Campylobacterspp. were surveyed in humans and representative poultry products over 3 years. One hundred and ninety-five representative isolates (n= 148,Campylobacter jejuni;n= 45,Campylobacter coli;n= 2Campylobacter hyointestinalis) were examined for genetic relatedness and antimicrobial susceptibility. Nearly allCampylobacterisolates (99.0%, 193/195) were resistant to at least one class of antimicrobials, and 45.6% (89/195) of the isolates exhibited multidrug resistance. Genotypic analysis revealed high diversity among tested strains. Multilocus sequence typing (MLST) displayed 120 sequence types (STs) including 42 novel STs being added to the PubMLST international database. Sixty-two STs belonged to 16 previously characterized clonal complexes (CCs), of which CC-21, CC-45, CC-464, CC-574, CC-353, and CC-828 were most frequently identified. In addition, pulsed-field gel electrophoresis (PFGE) fingerprinting resulted in 66 PFGESmaI patterns among the 125 isolates, with eight patterns shared between human and poultry sources. Subtyping data did not correlate with antimicrobial resistance phenotypes. Taken together, this large-scale surveillance study highlights high antimicrobial resistance and molecular features ofCampylobacterisolates in Southeastern China.

目的 了解2017年温州市沙门菌的血清型、 耐药情况和PFGE指纹图谱.方法 对分离自腹泻病例的77株沙门菌进行血清分型;采用微量肉汤稀释法对优势菌株进行12种抗生素的药敏试验;采用脉冲场凝胶电泳(PFGE)进行指纹图谱分型研究.结果 77株沙门菌共分为23种血清型,优势血清型为鼠伤寒沙门菌,22株占28.58％;肠炎沙门菌,11株占14.29％.33株优势血清型沙门菌对氨苄西林耐药率最高(84.85％),其次为四环素(69.70％)和萘啶酸(63.64％);多重耐药14株,占42.42％;除氨苄西林、 萘啶酸外,鼠伤寒沙门菌的耐药率普遍高于肠炎沙门菌.22株鼠伤寒沙门菌可分成16种PFGE指纹图谱;11株肠炎沙门菌分成3种PFGE指纹图谱.结论 温州市食源性沙门菌的血清型分布广泛,耐药状况严重,PFGE指纹图谱呈多样性,其聚集性与血清型存在关联性.