Background Salmonella, an important foodborne pathogen, was estimated to be responsible for 95.1 million cases and 50,771 deaths worldwide. Sixteen serovars were responsible for approximately 80% of Salmonella infections in humans in China, and infections caused by a few uncommon serovars have been reported in recent years, though not with S. Welikade. This study reports the first clinical case caused by S. Welikade in China and places Chinese S. Welikade isolates in the context of global isolates via genomic analysis. For comparison, S. Welikade isolates were also screened in the Chinese Local Surveillance System for Salmonella (CLSSS). The minimum inhibitory concentrations (MICs) of 28 antimicrobial agents were determined using the broth microdilution method. The isolates were sequenced on an Illumina platform to identify antimicrobial resistance genes, virulence genes, and phylogenetic relationships. Results The S. Welikade isolate (Sal097) was isolated from a two-year-old boy with acute gastroenteritis in 2021. Along with the other two isolates found in CLSSS, the three Chinese isolates were susceptible to all the examined antimicrobial agents, and their sequence types (STs) were ST5123 (n = 2) and ST3774 (n = 1). Single nucleotide polymorphism (SNP)-based phylogenetic analysis revealed that global S. Welikade strains can be divided into four groups, and these three Chinese isolates were assigned to B (n = 2; Sal097 and XXB1016) and C (n = 1; XXB700). In Group B, the two Chinese ST5123 isolates were closely clustered with three UK ST5123 isolates. In Group C, the Chinese isolate was closely related to the other 12 ST3774 isolates. The number of virulence genes in the S. Welikade isolates ranged from 59 to 152. The galF gene was only present in Group A, the pipB2 gene was only absent from Group A, the avrA gene was only absent from Group B, and the allB, sseK1, sspH2, STM0287, and tlde1 were found only within Group C and D isolates. There were 15 loci unique to the Sal097 isolate. Conclusion This study is the first to characterize and investigate clinical S. Welikade isolates in China. Responsible for a pediatric case of gastroenteritis in 2021, the clinical isolate harbored no antimicrobial resistance and belonged to phylogenetic Group B of global S. Welikade genomes.

为了解复旦大学附属金山医院近年来明显增多的非伤寒沙门菌(nontyphoidal Salmonella,NTS)感染儿童病例的临床特点及病原体特征,本研究回顾性分析了 2018年1月—2021年12月该院NTS感染患儿的临床特征、血清型分布及耐药情况,并比较新型冠状病毒感染(简称新冠)疫情出现前后的差异.2018-2021年该院腹泻患儿中NTS的平均分离率为18.1％(110/609),其中2020-2021年(新冠疫情开始后)的分离率(21.3％,57/268)明显高于2018-2019年(15.5％,53/341)(P=0.04).NTS感染病例主要集中在6个月～＜3岁年龄段(80.0％,88/110),多发于每年的5-10月(84.5％,93/110).临床症状常见发热(70.9％)和肉眼血便(22.7％);均接受第3代头孢菌素类抗生素治疗,疗程一般为5～7 d,所有患儿均临床痊愈.共检出21种血清型,其中鼠伤寒沙门菌单相变种最常见(29.1％,32/110),其次是鼠伤寒沙门菌(26.4％,29/110).药敏试验结果显示,NTS对头孢曲松的耐药率为21.8％,对阿奇霉素和环丙沙星的耐药率较低(分别为8.2％和6.4％);29.1％的菌株为多重耐药株,2.7％的菌株对所检测抗菌药物均耐药.NTS已成为上海金山及其周边地区儿童急性肠炎的重要病原体,且感染率呈上升趋势,很可能与鼠伤寒沙门菌及其单相变种感染增多有关,对目前临床常用的第3代头孢菌素类抗生素的耐药率较高,因此有必要持续监测NTS的流行特征及其对抗菌药物耐药性的变化.

Objective: Neisseria lactamica has an important influence on carriage and antimicrobial susceptibility of N. meningitidis, a major pathogen of septicemia and meningitis. In China, quinolone resistance is highly prevalent in N. meningitidis but unknown in N. lactamica. This study investigates the carriage rate, sequence type, and ciprofloxacin resistance of N. lactamica in children in China. Methods: During 2014-2016, throat swabs were collected from 2,239 children in Shanghai. The ciprofloxacin minimum inhibitory concentrations of the isolates were determined by the agar dilution method. Results: The overall carriage rate of N. lactamica was higher (8.9%) than that of N. meningitidis (0.9%) and peaked at two years (37.1%). The resistance frequency of N. lactamica to ciprofloxacin was 98.5% (197/200). There were 65 sequence types (STs). Clonal complex (cc) 640 (45.5%) dominated, while ST-14031 was predominant (37%, 74/200). All isolates possessed a GyrA mutation; 17 isolates (8.5%) harbored additionally a ParC mutation. Assigned to 39 different alleles, the gyrA sequences from these N. lactamica isolates formed an N. lactamica cluster, which also included eight alleles from N. meningitidis. Conclusion: The N. lactamica isolates in China showed distinct characteristics with lower genetic diversity and a much higher prevalence of quinolone resistance than in other countries. (C) 2019 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Streptococcus pyogenes, also known as group A Streptococcus (GAS), is one of the top 10 infectious causes of death worldwide. Macrolide and tetracycline resistant GAS has emerged as a major health concern in China coinciding with an ongoing scarlet fever epidemic. Furthermore, increasing rates of fluoroquinolone (FQ) non-susceptibility within GAS from geographical regions outside of China has also been reported. Fluoroquinolones are the third most commonly prescribed antibiotic in China and is an therapeutic alternative for multi-drug resistant GAS. The purpose of this study was to investigate the epidemiological and molecular features of GAS fluoroquinolone (FQ) non-susceptibility in Shanghai, China. GAS (n = 2,258) recovered between 2011 and 2016 from children and adults were tested for FQ-non-susceptibility. Efflux phenotype and mutations in parC, parE, gyrA, and gyrB were investigated and genetic relationships were determined by emm typing, pulsed-field gel electrophoresis and phylogenetic analysis. The frequency of GAS FQ-non-susceptibility was 1.3% (30/2,258), with the phenotype more prevalent in GAS isolated from adults (14.3%) than from children (1.2%). Eighty percent (24/30) of FQ-non-susceptible isolates were also resistant to both macrolides (ermB) and tetracycline (tetM) including the GAS sequence types emm12, emm6, emm11, and emm1. Genomic fingerprinting analysis of the 30 isolates revealed that non-susceptibility may arise in various genetic backgrounds even within a single emm type. No efflux phenotype was observed in FQ non-susceptible isolates, and molecular analysis of the quinolone resistance-determining regions (QRDRs) identified several sequence polymorphisms in ParC and ParE, and none in GyrA and GyrB. Expansion of this analysis to 152 publically available GAS whole genome sequences from Hong Kong predicted 7.9% (12/152) of Hong Kong isolates harbored a S79F ParC mutation, of which 66.7% (8/12) were macrolide and tetracycline resistant. Phylogenetic analysis of the parC QRDR sequences suggested the possibility that FQ resistance may be acquired through inter-species lateral gene transfer. This study reports the emergence of macrolide, tetracycline, and fluoroquinolone multidrug-resistant clones across several GAS emm types including emm1 and emm12, warranting continual surveillance given the extensive use of fluoroquinolones in clinical use.

Epidemics of scarlet fever started in China in 2011 .Most of the cases were represented by the classic type ,while the surgical type was rarely reported .It is unclear whether ICE‐emm12 and ΦHKU .vir , the two mobile genetic elements firstly discovered in the strains leading to scarlet fever outbreak in Hong Kong ,were carried by the strains in Mainland China . Here we reported a scarlet fever case in Zhejiang which was caused by Streptococcus pyogenes .Strains isolated from the pharynx and skin wound all carried ICE‐emm12 and ΦHKU .vir .The result suggests a screening of the two mobile genetic elements in Mainland China for genetic surveillance of scarlet fever .

>本研究采用多位点序列分型(MLST)技术分析上海地区2005—2009年脑膜炎奈瑟菌的优势基因型,以该优势型别的菌株作为靶菌,检测健康人群对于该菌株的血清杀菌力水平,评价本地区的疫苗免疫效果。1.材料与方法 :(1)试剂及仪器:质控血清由中国疾病预防控制中心传染病预防控制所提供。幼兔补体购自美国Pel-Freez公司。