对从印度本地治里一家三级医院儿童和成人腹泻粪便标本中分离出的致泻性大肠杆菌的毒力和抗菌耐药模式的研究。
A study of virulence and antimicrobial resistance pattern in diarrhoeagenic Escherichia coli isolated from diarrhoeal stool specimens from children and adults in a tertiary hospital, Puducherry, India.
作者信息
Natarajan Mailan, Kumar Deepika, Mandal Jharna, Biswal Niranjan, Stephen Selvaraj
机构信息
Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, 605006, India.
Department of Paediatrics, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, 605006, India.
出版信息
J Health Popul Nutr. 2018 Jul 13;37(1):17. doi: 10.1186/s41043-018-0147-z.
BACKGROUND
Emergence of atypical enteropathogenic Escherichia coli (EPEC) and hybrid E. coli (harboring genes of more than one DEC pathotypes) strains have complicated the issue of growing antibiotic resistance in diarrhoeagenic Escherichia coli (DEC). This ongoing evolution occurs in nature predominantly via horizontal gene transfers involving the mobile genetic elements like integrons notably class 1 integron. This study was undertaken to determine the virulence pattern and antibiotic resistance among the circulating DEC strains in a tertiary care center in south of India.
METHODS
Diarrhoeal stool specimens were obtained from 120 children (< 5 years) and 100 adults (> 18 years), subjected to culture and isolation of diarrhoeal pathogens. Conventional PCR was performed to detect 10 virulence and 27 antimicrobial resistance (AMR) genes among the E. coli isolated.
RESULTS
DEC infection was observed in 45 (37.5%) children and 18 (18%) adults, among which [18 (40%), 10 (10%)] atypical EPEC was most commonly detected followed by [6 (13.3%), 4 (4%)] ETEC, [5 (11.1%) 2 (2%)] EAEC, [(3 (6.6%), 0 (0%)] EIEC, [3 (6.6%), 0 (0%] typical EPEC, and [4 (8.8%), 1 (1%)] STEC, and no NTEC and CDEC was detected. DEC co-infection in 3 (6.6%) children, and 1(1%) adult and sole hybrid DEC infection in 3 (6.6%) children was detected. The distribution of sulphonamide resistance genes (sulI, sulII, and sulIII were 83.3 and 21%, 60.41 and 42.1%, and 12.5 and 26.3%, respectively) and class 1 integron (int1) genes (41.6 and 26.31%) was higher in DEC strains isolated from children and adults, respectively. Other AMR genes detected were qnrS, qnrB, aac(6')Ib-cr, dhfr1, aadB, aac(3)-IV, tetA, tetB, tetD, catI, blaCTX, blaSHV, and blaTEM. None harbored qnrA, qnrC, qepA, tetE, tetC, tetY, ermA, mcr1, int2, and int3 genes.
CONCLUSIONS
Atypical EPEC was a primary etiological agent of diarrhea in children and adults among the DEC pathotypes. Detection of high numbers of AMR genes and class 1 integron genes indicate the importance of mobile genetic elements in spreading of multidrug resistance genes among these strains.
背景
非典型肠致病性大肠杆菌（EPEC）和杂交大肠杆菌（携带不止一种致泻性大肠杆菌（DEC）致病型的基因）菌株的出现，使DEC中日益增长的抗生素耐药性问题变得更加复杂。这种持续的进化在自然界中主要通过水平基因转移发生，涉及整合子等移动遗传元件，尤其是1类整合子。本研究旨在确定印度南部一家三级医疗中心中循环DEC菌株的毒力模式和抗生素耐药性。
方法
从120名儿童（<5岁）和100名成人（>18岁）获取腹泻粪便标本，进行腹泻病原体的培养和分离。对分离出的大肠杆菌进行常规PCR检测，以检测10个毒力基因和27个抗菌耐药（AMR）基因。
结果
在45名（37.5%）儿童和18名（18%）成人中观察到DEC感染，其中[18名（40%），10名（10%）]非典型EPEC最常被检测到，其次是[6名（13.3%），4名（4%）]ETEC，[5名（11.1%），2名（2%）]EAEC，[(3名（6.6%），0名（0%）]EIEC，[3名（6.6%），0名（0%）]典型EPEC，以及[4名（8.8%），1名（1%）]STEC，未检测到NTEC和CDEC。检测到3名（6.6%）儿童和1名（1%）成人有DEC合并感染，3名（6.6%）儿童有单独的杂交DEC感染。从儿童和成人中分离出的DEC菌株中，磺胺耐药基因（sulI、sulII和sulIII分别为83.3%和21%、60.41%和42.1%、12.5%和26.3%）和1类整合子（int1）基因（41.6%和26.31%）的分布较高。检测到的其他AMR基因有qnrS、qnrB、aac(6')Ib-cr、dhfr1、aadB、aac(3)-IV、tetA、tetB、tetD、catI、blaCTX、blaSHV和blaTEM。未发现携带qnrA、qnrC、qepA、tetE、tetC、tetY、ermA、mcr1、int2和int3基因的菌株。
结论
在DEC致病型中，非典型EPEC是儿童和成人腹泻的主要病原体。大量AMR基因和1类整合子基因的检测表明移动遗传元件在这些菌株中多药耐药基因传播中的重要性。
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