Etiological Analysis Of Infectious Diarrhea In Haizhu District, Guangzhou City

Infectious diarrhea is the main clinical performance of gastroenteritis syndrome by pathogenic microorganisms, such as bacteria, viruses and parasites. Clinically, bacteria and viruses are the common ones. The incidence of diarrhea ranks top among the39kinds of notifiable infectious diseases in China. Diarrhea is a season disease of Summer and Autumn. While due to the characteristical climatic of warm and moist in Guangzhou, it also appeals in Spring and Winter. So far, a complete pathogenic spectrum survey is rare. As one of the sentinel hospitals of infectious diarrhea pathogenic suvellance, we built a technical platform of diarrhea pathogenic spectrum survey by using many kinds of advanced technologies such as the advanced mass spectrometry to detect diarrhea pathogens, colloidal gold immunochromatography assay real-time fluorescence quantitative PCR. This study was performed to detect the pathogen of diarrhea patients in Guangzhou in order to make a further understand the fetures of the pathogen of diarrhea. In addition, some pathogens become more and more important, but they have not been paid enough attention in clinical,such as Campylobacter, Aeromonas.In the previous work, we found that some serious diarrhea patients have not been found pathogens all the time and the treatment effect was not good. Combined comprehensive analysis of the infoumation of patients in the clinical with consulting the latest developments on diarrhea, we suspected patients may have a Clostridium difficile infection, and then we used the enzyme-linked fluorescent immunoassay analysis to detect Clostridium difficile toxin A&B antigen. We understand diarrhea on Clostridium difficile infection in Guangzhou in order to provide the basis for clinical diagnosis and treatment and prevention. This study consists the following two chapters:First Chart Etiological analysis of infectious diarrhea during winter and spring in Haizhu district,Guangzhou cityWe collected diarrhea stool samples in Southern Medical University Zhujiang Hospital from2012November to2013May. Through the questionnaire investigation and consulting the medical records to understand the patients’clinical information, we totally collected290specimens, including70inpatients and220outpatients. The median age is25months. According to the requirements of disease surveillance technology platform, bacterial pathogens and virus pathogens were detected.Firstly, all of the diarrheal stools which were accordance with diarrhea stool detection platform requirements were detected by the method for separation and cultivation, routine stool examination and occult blood test, immune chromatography detection of rotavirus antigen and adenovirus antigen. The left of stools were stored at-80℃refrigerator. Secondly, with comprehensive analysis of colonies in the various plates, we identified as much suspicious colonies as possible by matrix assisted laser desorption ionization time of flight mass spectrometer;Finally, we used serological tests to confirm some parts of species, according to the identified result. Slant three sugar iron and other ancillary tests were used to identify Aeromonas into species and fluorescence quantitative PCR was used to detect norovirus from samples which were stored at-80℃refrigerator.From the analysis of the overall population of diarrhea, it was divided into6groups according the standard of the development, which are infancy, early childhood, childhood, adolescence, adulthood and old age. We found the highest proportion was infancy group and the lowest was adolescence. From the analysis of diarrhea pathogens, the total positive rate was54.48%(158/290), the positive rate of bacteria infection was20.67%(60/290), virus infection positive rate was36.90%(107/290), mixed infection positive rate was7.59%(22/290). The positive rate of bacteria was significantly higher than that of virus, the positive rate and stool routine examination results of various types of mixing infections were no difference.In the detection of pathogenic bacteria, the firstly positive of Salmonella was44.78%(30/67), followed by Campylobacter28.36%(19/67) and Aeromonas14.93%(10/67), and there were no Vibrio cholerae, Vibrio parahaemolyticus and Vibrio mimicus In the detection of virus, the firstly positive of rotavirus is54.86%(62/113), followed by norovirus39.82%(45/113) and enteric adenovirus4.42%(5/113), of which norovirus II is more common. From the analysis of age, the positive rate of bacteria was higher in minors than that of adults, so is Campylobacter, but the positive rate of virus is no difference amog them.From the analysis of sex, the positive rate of virus is higher in male than that of in female, but there is no difference from the positive rate of bacteria between them. From the analysis of season, the highest positive rate of bacteria was in April, and the lowest was in January. As for virus, the highest was in January and the lowest was in May.A futher analysis were made to the top three bacterial and virus, we made the serological test and the drug sensitivity test of Salmonella. The results showed the most of Salmonella were A group, two were B group, while there was no other serogroup. The result of drug sensitive tests of28strains of resuscited Salmonella showed all strains were resistant to2kinds of antibiotics,, partly resistant to12kinds of antibiotics, such as ampicillin, topiperacillin,etc, fully sensitive to9kinds of antibiotics such as gentamycin, ciprofloxacin,etc.As for Campylobacter, we made a detailed analysis related to the clinical characteristics of patients with Campylobacter infection, which showed that the results of stool samples from Campylobacter infectious diarrhea were significantly higher than that of other bacterial diarrhea in the red blood cells, white blood cells and occult blood test. The main cause is that the patients with Campylobacter were overlooked because of the feature of itself, so that they did not receive timely effective treatment. The infection rate is rising year by year, we need to pay more attention to it.10detected Aeromonas were identified to species by other aided tests, respectively, of which were4Aeromonas sobria,2Aeromonas hydrophila,4Aeromonas caviae. Drug sensitive test of10strains of Aeromonas showed resistant to3kinds of antibiotics, partly resistant to6kinds of antibiotics and completely sensitive to12antibiotics including cefepime, which showed Aeromonas infection rate has been rising while multi drug resistance has emerged. From the study of virus infection, G1P8is the dominant strain for rotavirus which were91.94%in rotavirus positive specimens together With G9P8, G2P4and G3P8and we found G9P4strain which has not been reported in domestic yet. GII.4was the dominant strain for norovirus.There were7other genotypes,such as GI.1> GI.3、GI.4、GI.6、GI.2, GII.14、GII.G-12,which GI.6and GII.g-12have not been reported in domestic yet.Second chart Investigation of the distribution of Clostridium difficile among patients suffering from diarrheaFrom2013July to2013December, we collected diarrhea stool specimens in the Southern Medical University Zhujiang Hospital. Through the questionnaire investigation and consulting the medical records to understand the patient’s clinical information, we totally collected137specimens, including70inpatients and220outpatients,84male and53female. The oldest was85years old, the yonungest was11days, and the median age was22years old.In general, when we detected diarrhea pathegen, the prior consideration is the common pathogenic bacteria. Firstly, we detected Salmonella before screening Clostridium difficile, for the result of the first chapter shows that Salmonella is the most common pathogens of diarrhea diarrhea and it can be detected easily in the ordinary routine laboratory, Secondly, we use enzyme-linked fluorescent analysis to detect Clostridium difficile in the left specimens which is no Salmonella. Thirdly, we cultured8cases of samples of which Clostridium difficile toxin A&B antigen was positive and suspicious by the improved method, we inoculated centrifugation sediment which is bathed30minutes in70℃to anaerobic plate before put into a anaerobic gas agent anaerobic bag then we observed and identified the suspicious colonies after48hours. Finally, we analyzed the results between culture results and Clostridium difficile toxin A&B antigenic to make a futher understand the epidemiological characteristics of patients with positive toxin antigen detection.137specimens were collected for this research, including70inpatients and220outpatients, which including66children,46youths and25elderly, we use enzyme-linked fluorescent analysis to detect Clostridium difficile in the130specimens excerpt for7specimens with Salmonella. There were8patients with positive result. The positive rate is8.15%, We found the distribution was scattered by analysis the clinical information, of which2patients from Department of Gastroenterology,2patients from the Department of Hematology,2patients from the outpatient department of Pediatrics,1patients from department of kidney and1patients from the department of organ transplantation department. The positive rate of Children, youth and the elderly was4.76%,6.82%and8.70%, while there was no difference among them by statistical analysis. The results of cultivation showed that six cases of Clostridium difficile were found Clostridium difficile while2cases of Clostridium difficile was not found. Summarization: According to the results based on two chapters above, it can be concluded as follows:1、Based on the diarrhea pathogen spectrum, the total and bacteria positive rate was above that of reported because of making use of advanced mass-spectrometric technique to identify bacteria. The positive rate of the virus was higher than that of the bacteria. The top three pathogenic bacterial were Salmonella, Campylobacter and Aeromonas, while the top three pathogenic virus were rotavirus, norovirus, enteric adenovirus.2、Based on the analysis of diarrhea epidemiology, the median age was25months among the cases of collected samples of diarrhea. According to the developmental characteristics grouped by age, the infant population with diarrhea accounted for the largest proportion while adolescent group is the lowest. Patients with viral diarrhea and bacterial diarrhea vary across gender, age and occurence time between when conducting screening of the diarrhea pathogens.3、There are some new changes in diarrhea pathogens. Firstly, the positive rate of Campylobacter, which is a zoonotic pathogen is higher among the minor group than that of the adult group. We suggest that stool from the minor group with diarrhea should be detected Campylobacter regularly in order to reduce the misdiagnosis. Secondly, the positive rate of Aeromonas which is a zoonotic pathogen ranked the third,too.It was often overlooked for clinical symptoms which was infected by Aeromonas was not severe. We should pay more attention on diarrhea which is caused by Aeromonas and their drug sensitivity test.4、There are some new changes on drug sensitivity test. Firstly, all of the28strains of Salmonella and10strains of Aeromonas have trend of multi drug resistance. Secondly, Salmonella and Aeromonas are fully sensitive to antibiotics which represents Carbapenems, quinolones and aminoglycosides. Thirdly, the drug sensitivity tests from Salmonella are more severe than that of Aeromonas. 5、Diverse virus genotype. G1P8together with G9P8, G2P4and G3P8were91.94%in rotavirus positive specimens and we found G9P4strain which has not been reported in domestic. GII.4is the dominant strain for norovirus. There were7other genotype,which GI.6and GII.g-12have not been reported in domestic yer.6、There are some changes on susceptible population with Clostridium difficile infection. We should focus on the hospitalized patients, as well as those from the community clinics. We should focus on the elderly population, as well as the children. Clostridium difficile infection may be found across different departments within the same hospital, which suggest Clostridium difficile infection can be found in any diseases and any people..7、Technologies to detect Clostridium difficile have been improving. In comparison to the culturing mothod, enzyme-linked fluorescent analysis which is used to detect Clostridium difficile infection is commercialized now. It is a simple, rapid, and highly sensitive approach, which can be used in large scale screening.