2008年至2017年河南省睢县腹泻患儿志贺菌血清型分布及耐药研究

Serotype distribution and drug resistance of Shigella in children with diarrhea from 2008 to 2017 in Sui County,Henan Province

目的了解2008年至2017年河南省睢县5岁以下腹泻患儿粪便标本中志贺菌的血清型分布和耐药情况。方法采集2008年至2017年河南省睢县豆付元卫生室的4721份5岁以下腹泻患儿粪便标本,细菌培养分离出志贺菌株。采用玻片凝集试验进行血清学分型。按比例选取271株志贺菌株,采用多重梯度聚合酶链反应检测毒力基因,Kirby-Bauer琼脂法进行药物敏感试验。采用趋势性卡方检验分析耐药性年度变化趋势。结果4721份粪便标本中志贺菌检出率为20.69%(977/4721)。977株志贺菌共分为2群13种血清型,福氏志贺菌占77.79%(760/977),宋内志贺菌占22.21%(217/977),每年最常见的3种血清型呈交替变化。271株志贺菌中,福氏志贺菌优势基因携带模式为志贺菌肠毒素(Shigella enterotoxin,shET)-1+、shET-2+、侵袭性质粒H抗原(invasion plasmid antigen H,ipaH)+、侵袭相关毒力基因(invasion-associated locus,ial)+,占84.04%(179/213);宋内志贺菌为shET-1-、shET-2+、ipaH+、ial+,占46.55%(27/58)。志贺菌对氨苄西林、萘啶酸、四环素的耐药率均>90%,对头孢吡肟和头孢他啶较敏感;对头孢噻肟、头孢吡肟、环丙沙星、氯霉素和复方磺胺甲唑的耐药率逐年上升,差异有统计学意义(χ^2=24.027、7.232、6.039、4.764、6.809,均P<0.05)。98.52%(267/271)的菌株对3种以上抗菌药物耐药,福氏志贺菌对环丙沙星、诺氟沙星、氯霉素的耐药率均高于宋内志贺菌;对庆大霉素和复方磺胺甲唑的耐药率均低于宋内志贺菌,差异均有统计学意义(χ^2=31.866、14.868、83.036、68.534、14.738,均P<0.01)。结论2008年至2017年睢县5岁以下腹泻患儿志贺菌每年主要流行的血清型不断发生变化,不同血清分型的优势基因携带模式不同。大多数分离菌株产生了多重耐药,且不同血清型的志贺菌耐药谱不同。

Objective To explore the serotype distribution and drug resistance of Shigella in stool samples of children under five years old with diarrhea from 2008 to 2017 in Sui County,Henan Province.Methods A total of 4721 stool samples of children under five years old with diarrhea were collected from Doufuyuan Clinic of Sui County during 2008 to 2017,and Shigella strains were isolated through bacterial culture.The slide agglutination test was used for serotyping of Shigella strains.Two hundred of seventy-one Shigella strains were selected in proportion,and multiple gradient polymerase chain reaction was used to detect virulence genes and Kirby-Bauer agar method was used for drug sensitivity.Trend chi square test was used to analyze the annual trend of drug resistance.Results The detection rate of Shigella strains in 4721 fecal samples was 20.69%(977/4721).A total of 977 Shigella strains were divided into 13 serotypes in two groups,including 77.79%(760/977)Shigella flexneri strains and 22.21%(217/977)Shigella sonnei strains.The top three serotypes detected alternately every year.The dominant gene pattern of Shigella flexneri was Shigella enterotoxin(shET)-1+,shET-2+,invasion plasmid antigen H(ipaH)+,invasion-associated locus(ial)+,accounted for 84.04%(179/213)and that of Shigella sonnei was shET-1-,shET-2+,ipaH+,ial+,accounted for 46.55%(27/58).The drug resistance rates of 271 Shigella strains to ampicillin,nalidixic acid and tetracycline were more than 90%and the strains were more sensitive to cefepime and ceftazidime.The drug resistance rates to cefotaxime,cefepime,ciprofloxacin,chloramphenicol and sulfamethoxazole/trimethoprim increased year by year,and all had statistically significant differences(χ^2=24.027,7.232,6.039,4.764 and 6.809,respectively,all P<0.05).There were 98.52%(267/271)strains resistant to more than three kinds of drugs.The resistance rates of Shigella flexneri to ciprofloxacin,norfloxacin,and chloramphenicol were higher than those of Shigella sonnei,and the resistance rates to gentamicin and sulfamethoxazole/trimethoprim were lower than those of Shigella sonnei.The differences were statistically significant(χ^2=31.866,14.868,83.036,68.534 and 14.738,respectively,all P<0.01).Conclusions The major serotypes of Shigella in children under five years old in Sui County are constantly changing from 2008 to 2017.The dominant gene patterns of different serotypes are different.Most isolated strains have multiple drug resistances,and different serotypes have different resistance profiles.