Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Jalal-Ale-Ahmad Ave, Tehran, 14117-13116, Iran.
BMC Infect Dis. 2021 Jan 23;21(1):108. doi: 10.1186/s12879-021-05778-5.
Campylobacter jejuni (C. jejuni) is a leading cause of acute gastroenteritis in human worldwide. The aim of study was to assess the distribution of sialylated lipooligosaccharide (LOS) classes and capsular genotypes in C. jejuni isolated from Iranian children with gastroenteritis. Furthermore, the level of dnaK gene expression in C. jejuni strains with selected capsular genotypes and LOS classes was intended. Moreover, a comprehensive study of C. jejuni MLST-genotypes and inclusive comparison with peer sequences worldwide was intended.
Twenty clinical C. jejuni strains were isolated from fecal specimens of 280 children aged 0-5 years, suspected of bacterial gastroenteritis, which admitted to 3 children hospitals from May to October, 2018. Distribution of sialylated LOS classes and specific capsular genotypes were investigated in C. jejuni of clinical origin. The expression of dnaK in C. jejuni strains was measured by Real-Time-PCR. MLST-genotyping was performed to investigate the clonal relationship of clinical C. jejuni strains and comparison with inclusive sequences worldwide.
C. jejuni HS23/36c was the predominant genotype (45%), followed by HS2 (20%), and HS19 and HS4 (each 10%). A total of 80% of isolates were assigned to LOS class B and C. Higher expression level of dnaK gene was detected in strains with HS23/36c, HS2 and HS4 capsular genotypes and sialylated LOS classes B or C. MLST analysis showed that isolates were highly diverse and represented 6 different sequence types (STs) and 3 clonal complexes (CCs). CC21 and CC257 were the most dominant CCs (75%) among our C. jejuni strains. No new ST and no common ST with our neighbor countries was detected.
The C. jejuni isolates with LOS class B or C, and capsular genotypes of HS23/36, HS2, HS4 and HS19 were dominant in population under study. The CC21 and CC257 were the largest CCs among our isolates. In overall picture, CC21 and CC353 complexes were the most frequently and widely distributed clonal complexes worldwide, although members of CC353 were not detected in our isolates. This provides a universal picture of movement of dominant Campylobacter strains worldwide.
空肠弯曲菌（C. jejuni）是全球人类急性胃肠炎的主要致病原因。本研究旨在评估从伊朗患胃肠炎的儿童中分离的空肠弯曲菌中唾液酸化脂寡糖（LOS）类和荚膜基因型的分布。此外，旨在研究选定荚膜基因型和 LOS 类别的空肠弯曲菌菌株中 dnaK 基因的表达水平。此外，旨在对空肠弯曲菌 MLST 基因型进行全面研究，并与全球同行序列进行综合比较。
2018 年 5 月至 10 月，从 3 家儿童医院收治的 280 名 0-5 岁疑似细菌性胃肠炎的儿童粪便标本中分离出 20 株临床分离的空肠弯曲菌。研究了临床来源的空肠弯曲菌中唾液酸化 LOS 类和特定荚膜基因型的分布。通过实时 PCR 测量 C. jejuni 菌株中 dnaK 的表达。进行 MLST 基因分型以调查临床空肠弯曲菌分离株的克隆关系，并与全球包容性序列进行比较。
HS23/36c 是主要基因型（45%），其次是 HS2（20%），HS19 和 HS4（各 10%）。80%的分离株被分配到 LOS 类 B 和 C。HS23/36c、HS2 和 HS4 荚膜基因型和唾液酸化 LOS 类 B 或 C 的菌株中，检测到 dnaK 基因的高表达水平。MLST 分析表明，分离株高度多样化，代表 6 种不同的序列类型（ST）和 3 个克隆复合体（CC）。CC21 和 CC257 是我们的空肠弯曲菌菌株中最主要的 CC（75%）。未发现新的 ST，也未发现与邻国相同的 ST。
在研究人群中，LOS 类 B 或 C 型和 HS23/36、HS2、HS4 和 HS19 荚膜基因型的空肠弯曲菌分离株占主导地位。CC21 和 CC257 是我们分离株中最大的 CC。总体而言，CC21 和 CC353 复合体是全球最常见和分布最广的克隆复合体，尽管我们的分离株中未检测到 CC353 成员。这提供了全球主导弯曲菌菌株运动的普遍情况。
