[Monitoring and research on pathogen spectrum in patients with acute diarrhea from sentinel hospital of Zhejiang Province during 2009 to 2014]

Objective: To explore pathogen spectrum constitution of acute diarrhea in outpatient and emergency of Zhejiang Province, and provide basis for treatment, prevention and control of the disease. Methods: During January 2009 to December 2014, we selected seven sentinel hospitals in different regions of Zhejiang, monitored and researched on pathogen spectrum in patients with acute diarrhea from outpatient and emergency. We recorded patients’ personal basic information, the main symptoms and signs, and collected stool samples (5 g). Eight kinds of bacteria ( Vibrio cholerae, Shigella spp., Salmonella spp ., Diarrheagenic E. coli, Vibrio parahaemolyticus, Aeromonas hydrophila, Yersinia enterocolitica and Plesiomonas shigelloides ) and five kinds of viruses ( Rotavirus, Norovirus, Sappovirus, Astrovirus and Adenovirus ) were detected. Chi-square test and Fisher’s exact probability method were used to compare different characteristics of patients with single bacterial infection, single virus infection and multiple infection (bacteria-bacteria, bacteria-viruses, virus-virus). Results: During 2009 to 2014, 9 364 fecal samples from acute diarrhea patients were collected and tested, among which 3 500 cases were tested positive, with total positive rate of 37.38%. Positive rates of bacteria and viruses were 13.14% (1 230 cases) and 20.75% (1 943 cases), respectively. Mixed infection positive rate of multiple pathogens was 3.49% (327 cases). Positive rate of Vibrio parahaemolyticus (5.96% , 558 cases) was the highest among bacterial pathogens, followed by pathogenic Escherichia coli (3.86%, 361 cases). Viruses were mainly Norovirus (10.73%, 1 005 cases) and rotavirus (8.35%, 782 cases). A big difference existed in diarrheogenic pathogen spectrum between patients less than 15 years old and patients equal or older than 15 years old. Pathogens for patients less than 15 years old were mainly virus, with the positive rate of 32.69% (1 014 cases). However, the positive rate of bacteria was 16.86% (1 056 cases) in patients equal or older than 15 years old. Single bacterial infection was highest in age group of 25-34 years old (18.62%, 302 cases) , single virus infection was highest in age group of 1-4 years old (41.12%, 435 cases) , and mixed infections of multiple pathogens were mainly existed in age group of 1-4 years old (7.37%, 78 cases) . Pathogen positive rate were increasing year by year. Pathogen positive rate of patients with acute diarrhea has obvious seasonality, with single bacterial infection being highest during July to September and single virus infection being highest during December to March. Pathogen spectrum of outpatient and emergency patients with acute diarrhea in Zhejiang Province changed a little from 2009 to 2014, mainly rotavirus (22.34% (782/3 500)), norovirus (28.71% (1 005/3 500)), vibrio parahaemolyticus (15.92% (558/3 500)) and Escherichia coli (10.31% (361/3 500)). However, pathogen spectrums in different years owned different features. Conclusion: Common pathogens in outpatient and emergency patients with acute diarrhea in Zhejiang Province were tested with significant seasonal epidemic law. The composition of pathogenic spectrum was variant in different age group. Constitutes of major pathogen spectrum in different years differed a little.