The Spectrum And Co-infection Of Enteric Pathogens In Diarrhea Cases In The Hospitals Of Kunming,Yunnan Province

Diarrhea is one of severe public health problems until now, which caused 2.8 billion diarrhea episodes and 1.2 million deaths in worldwide annually, and diarrhea caused 1.7 billion episodes and 700 thousand death children under five years. Intestinal pathogens are one of important causes of acute diarrhea. Enteric pathogens in diarrhea patients as followed:Diarrheagenic Escherichia coli （DEC）, Non-typical Salmonella spp （NTS）., Shigella spp., Cholerae, V. parahaemolyticus, Aeromonas spp., Pseudomonas spp., Rotavirus （RVA）, Norovirus （NoVs）, Sappovirus （SaV）, Astrovirus （As） and Adenovirus （Ad）, Blastocystis hominis （Bh）, Cryptosporidium spp. and Giardia lamblia etc..In order to grasp the pathogenic spectrum in acute diarrhea patients, the epidemiological features of co-infection among enteric pathogens, and the drug resistance characteristics of enteric bacterial pathogens. From 1st July 2014 July to 30th June 2015, four sentinel hospitals were recruited into the study in Kunming of Yunnan Province, such as The First People’s Hospital of Yunnan Province, The First Affiliated Hospital of Kunming Medical University, The Kunming Children’s Hospital and The Pushan Community Hospital.1 The spectrum of enteric pathogens in diarrhea casesThe 1121 diarrhea cases were recruited in the study, which included 850 diarrhea cases under five years and 271 patients over five years, and 319 healthy controls, which included 170 healthy controls under five years and 149 non-diarrhea cases over five years.At least one pathogen was isolated from in 484 （43.2%） acute gastroenteritis cases and 42 （13.2%） healthy controls across all age group （x2=96.5, P<0.05）. The prevalence of specific enteric pathogens in diarrhea cases was higher than that of in healthy controls as followed:DEC （x2=19.1, P<0.05）, NTS （x2=9.21, P<0.05）, RVA （X2=55.0, P<0.05） and NoVs GⅡ （x2=16.1, P<0.05）. The detection rate of other enteric pathogen in diarrhea cases was as high as that of in healthy controls. In diarrhea patients,RVAwas the most common enteric pathogen in diarrhea cases （21.8%, n=244）, followed by DEC （11.2%, n=126）, NoVs GⅡ （10.5%, n=118）, Bh （4.2%, n=47）, NTS （3.5%, n=39）, As （0.9%, n=10）, Ad （0.2%, n=2）, Cryptosporidium spp. （0.1%, n=1）, Shigella spp., Vibrio parahaemolyticus, Cholera and Giardia lamblia spp. was not found in diarrhea cases.The prevalence of at least enteric pathogen was 47.5% in 850 diarrhea cases under five years, and was 29.2% in 271 diarrhea patients over five years. At least one intestinal pathogen was detected more often in diarrhea cases under five years than that of diarrhea patients over the five years （χ2=28.7, P<0.05）. The prevalence of RVA （χ2=43.4, P<0.05） and NTS （x2=7.99, P<0.05） in diarrhea cases under five years was higher than that of in diarrhea patients over five years. No significant difference of other specific enteric pathogen was found among diarrhea cases under five years and diarrhea patients over five years.The most common enteric pathogen was detected in diarrhea cases less than five years as followed:RVA （26.4%, n=224）, NoVs GⅡ（11.1%, n=94）, DEC （10.6%, n=90）, NTS （4.4%, n=37）, Bh （4.0%, n=34）; the most common enteric pathogen was found in diarrhea patients over five years as followed:DEC （13.3%, n=36）, NoVs GⅡ （8.5%, n=24）, RVA （7.4%, n=20）, Bh （4.8%, n=13） and NTS （0.7%, n=2）.2 The epidemic features of co-infection among enteric pathogensThe prevalence of co-infection in diarrhea cases was higher than that of in non-diarrhea cases across all age group （17.3%, n=194; 2.8%, n=5;χ2=43.1, P<0.05）. In subjects under five years, the prevalence of co-infection in patients was higher than that of in healthy controls （20.0% vs.8.5%;χ2=21.2, P<0.05）.In diarrhea cases under five years, the RVA-NoVs GⅡ （4.4%） was the most common co-infection detected in diarrhea cases followed by DEC-RVA （2.3%） and DEC-NoVs GⅡ（1.1%）.3 The molecular epidemic features of mainly enteric pathogen isolated from diarrhea casesAmong the 244 RVA positive samples identified from diarrhea cases,235 RVA positive samples were identified in both G and P genotypes. For the G genotypes, G9 （66.4%, n=156） was most common genotype, followed by G3 （18.7%, n=44）, G1 （8.9%, n=3） and G2 （8.5%, n=2）; among the P genotypes, the predominant genotype was P[8] （92.8%, n=218）, followed by P[4] （4.7%, n=11）. G9P[8] （57.0%, n=134） was the predominant combinations of G and P genotypes, followed by G3P8 （18.3%, n=43） and G1P[8] （8.9%, n=21）, theses common three genotypes was accounted for 84.2% in all RVA strains identified in this study.Of 118 strains NoVs GⅡ isolated from diarrhea cases, the predominant genotype was NoVsGⅡ.4 （46.6%, n=55）, followed by GII.3 （23.7%, n=28）, GⅡ. 12 （21.2%, n=25）, GⅡ.17 （6.8%, n=8）, GⅡ.5 （1.7%, n=2）. Among the 55 strains NoVs GⅡ.4, GⅡ.4_Sydney strain （94.5%, n=52） was the predominant prevalence, followed by GⅡ.4₂006b （5.5%, n=3）, the GII.4_Orleans2009 was not detected in diarrhea patients.Of the 126 strains bacterial pathogen isolated from patients, EPEC （Enteropathogenic Escherichia coli） was the most common subtype （49.2%, n=62） of DEC, followed by EAEC （Enteroaggregative Escherichia coli,48.4%, n=61）, there two subtypes were the two most often common subtypes of DEC. DEC had high polymorphism, which suggested that no preponderant clone strain of DEC was found.Of 39 NTS strains, the predominant serotype was Salmonella enteritidis （51.3%, n=20）, followed by Salmonella typhimurium （25.6%, n=10）. The pulsotype pattern showed that S. enteritis had high similarity which suggested that S. enteritis strains formed one preponderant clone strains in sporadic diarrhea case, but the pulsotype patterns of S. typhimurium strains was discretely, which suggested that S. typhimurium did not form preponderant clone strain.Of the 47 strains Bh isolated from diarrhea patients,46 strains was the subtype I （97.9%, n=46）, one strain the subtype II （2.1%, n=1）.4 Resistance of bacterial pathogenThe resistance rate of strains to ciprofloxacin was 6.0%（n=10）, to cephalothin was 26.5%（n=44）, to cefotaxime was 28.9%（n=48）. The prevalence of multi-drug resistance to DEC was very common （82.5%, n=104）, to NTS strain was 76.9% （n=30）.In conclusion, RVA, NoVs GⅡ, DEC and NTS were the prominent prevalence enteric pathogens in diarrhea cases. The co-infection of enteric pathogens was high prevalence in diarrhea cases. The prominent genotype of RVA was G9P[8], the prominent genotype was NoVs GⅡ was GⅡ.4, the EPEC and EAEC were two subtypes of DEC in diarrhea cases. Salmonella enteritidis and Salmonella typhimurium were most common NTS. The resistance of bacteria strains was very seriously.