The Distribution Characteristics And Antimicrobial Resistance Of Aeromonas From Patients With Acute Diarrhea In Zhejiang Province

ObjectiveAeromonas was widely exists in nature,especially in the water environment,it can infect fishes,animals and human.Large-scale outbreaks of Aeromonas infections have happened in a number of countries and regions.It has not only become the main threat to the development of Chinese aquaculture industry,but also caused separate and mixed infection of human,leading to human intestinal infection and parenteral infection.The Aeromonas has become one of the common pathogens of summer diarrhea in China,which has threatened public health seriously.The distribution and the drug resistance characteristics of Aeromonas has been reported in many regions of the world.However,there are few reports on the research of Aeromonas in China.In the present study,we collected stool specimens of patients with acute diarrhea in Zhejiang province for the idenfication of Aeromonas,to clarify the satuation of Aeromonas infection and provide data for performing routine clinical testing more scientifically,and through susceptibility testing,to understand characteristic of antimicrobial resistance of Aeromonas in the studied area.We have provided information on the epidemiology for the prevention and control of Aeromonas,and laid the foundation for the further study.MethodsDuring January 2010 to December 2015,we collecte stool speciments with acute diarrhea from 6 sentinel hospitals from Zhejiang province.The isolations of bacterial pathogens were carried out by the standarded testing procedures.Bacterial pathogens were identified by the Biotyper MALDI-TOF MS system.We then performed susceptibility test for all the collected Aeromonas strains,and analysed the epidemiological characteristics of Aeromonas using the data from the clinical.Results1.From January 2010 to December 2015,we collected a total of 8589 stool specimens from patients with acute diarrhea,with 503 positve for Aeromonas,and the proportion is 5.9%.The results of identification by the Biotyper MALDI-TOF MS system showed that Aeromonas caviae(194,38.6%)were the main pathogens in the intestinal strains,followed by Aeromonas veronii(142,28.2%),Aeromonas hydrophila(80,15.9%),Aeromonas enteropelogenes(45,8.9%),Aeromonas ichthiosmia(27,5.4%),Aeromonas jandaei(14,2.8%),Aeromonas allosaccharophila(1,0.2%).2.There was gender difference in the proportions of Aeromonas(P<0.05),and the female has higher proportion(6.5%).The differences in the proportions of Aeromonas between age groups were significant(P<0.05),and the Middle-aged of 45-59 has the highest proportion(7.6%).The differences in the proportions of Aeromonas in different seasons was also significant(P<0.05),and the highest proportion(10.2%)of Aeromonas was in summer.3.Aeromonas maintained high sensitivity to most of the 17 antibiotics used in the study,and the rate of sensitivity to amikacin was up to 94.8%,levofloxacin 93.8%,gentamicin 92.4%,ceftazidime 92.0%.But the antimicrobial sensitivity of Aeromonas strains to tetracycline,imipenem,and cefoxitin were relatively low(59.0%,59.8%,and 61.9%),and many strains present moderately sensitivity to imipenem and tetracycline(20.7%,and 16.1%).4.Of Aeromonas caviae isolates,the highest rate of sensitivity to amikacin was 94.8%,while the rate of sensitivity to cefuroxime was 43.0%.Of Aeromonas veronii isolates,the highest rate of sensitivity to aztreonam was 97.9%,while the rate of sensitivity to imipenem was 25.4%,but meropenem was 78.9%.Of Aeromonas hydrophila isolates,the highest rate of sensitivity to amikacin and aztreonam were 97.5%,while the rate of sensitivity to cefoxitin was 35.0%.Of Aeromonas enteropelogenes isolates,the rate of sensitivity to ceftazidime,ceftriaxone,and levofloxacin were 100%,while the rate of sensitivity to cefoxitin was 60.0%.Of Aeromonas ichthiosmia isolates the rate of sensitivity to ceftazidime and levofloxacin were 100%,while the rate of sensitivity to tetracycline was 48.1%.Of Aeromonas jandaei isolates the rate of sensitivity to amikacin,piperacillin-tazobactam,gentamicin,cefepime,cefotaxime,and ceftriaxone were 92.9%,while the rate of sensitivity to imipenem was 28.6%.Of Aeromonas caviae isolates and Aeromonas ichthiosmia isolates the rate of sensitivity to imipenem was higher than other kinds of Aeromonas(P<0.05).Of Aeromonas veronii isolates and Aeromonas ichthiosmia isolates the rate of sensitivity to cefoxitin and cefuroxime was higher than other kinds of Aeromonas(P<0.05).The antimicrobial sensitivity of Aeromonas veronii and Aeromonas hydrophila to the 17 antibiotics used in the study were relatively low.5.128 strains of 503 aeromonas isolates were co-infected with other bacteria or viruses.Aeromonas caviae(36,28.1%)and Aeromonas veronii(37,28.9%)were the main species.But Aeromonas ichthiosmia and Aeromonas jandaei were easier to mix with the other pathogens,and the rates of the mixed infection were 50.0%and 44.4%,respectively.Conclusions1.Aeromonas was the third most prevalent bacterial pathogen in patients with acute diarrhea in Zhejiang,with the proportion reached 5.9%.2.Aeromonas caviae,Aeromonas veronii and Aeromonas hydrophila were the prevalent species in patients with acute diarrhea in Zhejiang.3.Aeromonas of the intestinal infection in the region were sensitive to amikacin,levofloxacin,gentamicin,and ceftazidime.But the antimicrobial sensitivity of Aeromonas strains to tetracycline,imipenem,and cefoxitin were relatively low.The sensitivity of different bacterial species of Aeromonas to antibiotics was various.