| Objective:To study the distribution of main enteropathogenic bacteria with ID(infectious diarrhea)in children in Chongqing in recent 27 years,and the resistance of enteropathogenic bacteria,especially Salmonella typhimurium(ST)in the last 10 years,and provide scientific basis for the prevention and treatment of bacterial enteritis in children in Chongqing.Methods:To investigate 33957 fecal specimens of diarrhea in children submitted to the Laboratory of Infectious Diseases department in Children's Hospital Affiliated to Chongqing Medical University during the past 27 years between 1991 to 2017,analyze the isolated strains and their corresponding clinical data,compare the distribution of main enteropathogenic bacteria in three different ages between 1991 to1999,between 2000 to 2008 and between 2009 to 2017,and compare drug resistance of enteropathogenic bacteria,especially ST in two different ages between 2008 to 2012,between 2013 to 2017.Results:In this study,2409 fecal samples positive were collected.Thetotal detection rate was 7.09%(2409/33957).Of these,1899 were Shigella spp.,319 were Salmonella spp.,122 were E.coli(Escherichia coli),and 41 were Pseudomonas aeruginosa.The peak of detection was from August to October,with 368,474 and 364 strains respectively.The highest detection rate was in 1995,which was 27.67%.There were 1379 males and 1030 females.The ratio of male to female was about 1.34:1.There were 1658 children from towns,751 children from rural areas,and the ratio between towns and rural areas was 2.21:1.The minimum age is 2 days,and the maximum age is 17 years and 8 months.The median age is 3 years and 4months(1 year and 6 months-3 years and 7 months).Among them,the children aged from 1 to 2 year-old has the largest proportion(16.36%),followed by the baby aged less than 1 year-old(15.86%),mostly children under 5 years old.Comparing the three groups of which are between 1991 to 1999,between 2000 to 2008,and between 2009 to 2017 years,the median age(3 years and 9 months)and the ratio between urban and rural areas were the highest between 1991 to 1999,the median age was the youngest(1 year old)between 2009 to 2017,and the ratio of urban and rural children was the smallest between 2000 to 2008.There was no statistically significant difference between the three groups(P<0.05).Among the enteropathogenic bacteria detected,Shigella was dominant(78.83%),mainly S.flexneri(Shigella flexneri)(87.36%),and mostly S.flexneri Type Two(97.17%),accounting for 66.92% of the totalenteropathogenic bacteria,followed by S.sonnei(Shigella Sonnei),accounting for only 12.64% of Shigella and 9.96% of the total enteropathogenic bacteria.The majority of Salmonella spp.was ST(69.28%),accounting for 9.17% of the total enteropathogenic bacteria,and EPEC(Enteropathogenic E.coli)made up the most of E.coli(77.05%),accounting for 3.90% of the total enteropathogenic bacteria.The detection of S.flexneri Type Two were concentrated from 1991 to 2008,most of which were between 1991 to 1999(92.87%).Only three S.sonnei were detected between 2009 to 2017,and S.flexneri was never detected.The number of ST increased significantly and the rate of detection was 1.01%between 2009 to 2017.The proportion of S.sonnei was higher than that of the ST in town,and the proportion of the ST was higher than that of S.sonnei in the rural areas.No matter in town or in rural areas,the proportion of S.flexneri was the highest,and the proportion of EPEC was the lowest among the four.The detection rate of main enteropathogenic bacteria in preschool children was the highest(35.76%),while that in adolescence was significantly lower.The detection rates of S.flexneri Type Two and S.sonnei were mainly in early childhood,preschool age and school age,while ST and EPEC were mainly detected in infants and young children.EPEC was not detected in children older than13 years.The drug resistance of enteropathogenic bacteria between 2008 to2017: the drug resistance rates of aztreonam,ampicillin,erythromycin,clindamycin,and compound sulfamethoxazole were all above 93%.In cephalosporins,cefazolin has a higher drug resistance rate and lower resistance to ceftriaxone.The resistance rates of cephamycins(cefoxitin),fluoroquinolones(ciprofloxacin,ofloxacin,norfloxacin),aminoglycosides(Amikacin,gentamicin),and macrolides(azithromycin,erythromycin)were respectively 33.33% to 100%,0% to 83.33%,60% to 100%,and 0%to 100%.The drug resistance of ST between 2008 to 2017: Ofloxacin has the lowest drug resistance rate(15.46%),the drug resistance rates of aztreonam,ampicillin,ceftazidime,erythromycin,clindamycin,compound sulfamethoxazole were over 93%,and cefoxitin had the lowest resistance rate in cephalosporins(35.42%).Compared with 2008 to 2012 and 2013 to2017,the drug resistance rate of amikacin decreased significantly from100% to 59.74%.The drug resistance rates of ciprofloxacin,norfloxacin and cefazolin did not decreased significantly,and drug resistance of ceftriaxone and ceftazidime did not increase significantly.Conclusions:The enteropathogenic bacteria of ID was mostly S.flexneri Type Two in the early stage(between 1991 to 1999),while ST was more predominant in the last 9 years(between 2009 to 2017),and no more S.flexneri Type Two was detected in this period.The majority of children were under 5 year-old,the number of children in urban area is higher than that in the rural,and it is high in the summer and autumn.In the past 10 years(between 2008 to 2017),the resistance toenteropathogenic bacteria is severe.In the drug resistance analysis of ST,the resistance rate of ofloxacin is the lowest,and the resistance rate of cefoxitin is the lowest in cephalosporins.The resistance rate of amikacin has dropped significantly in the past 5 years(between 2013 to 2017). |
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