ABSTRACT
Objective To understand the distribution and drug-resistance characteristics of diarrhea related etiology in Panzhihua City, and to provide the basis for epidemiological investigation and clinical diagnosis and treatment. Methods The fecal samples of 779 patients with diarrhea in Panzhihua city from October 2019 to October 2020 were collected. The pathogenic bacteria of diarrhea were isolated and drug sensitivity test was conducted. The epidemiological data of the occurrence of diarrhea, such as age and season, were analyzed and summarized. Results Atotal of 175 strains of pathogenic bacteria were isolated from the fecal samples of 779 diarrhea cases, with the isolation rate of 22.46% (175/779), including 65 strains of Salmonella, 39 strains of Vibrio, 51 strains of diarrheagenic Escherichia coli, 13 strains of Campylobacter and 7 strains of Shigella. 121 diarrhea virus positive samples were detected, and the positive detection rate was 15.53% (121/779). There were 55 cases of GII norovirus, 15 cases of GI, 45 cases of rotavirus, 2 cases of zaravirus and 4 cases of adenovirus. A total of 296 positive samples of pathogenic bacteria and viruses from diarrhea were collected, including 175 males (59.12%) and 121 females (40.88%), with a male to female ratio of 1.45:1. The age range was 2-65 years old, and the average age was (37.14±6.18) years old. The positive rate in the 0-14 year group was the highest (P2 =7.915)..The detection of diarrhea pathogenic bacteria showed obvious seasonality, and the positive rate was the highest in the third quarter (July to September) (P<0.05). The positive rate of diarrhea associated virus was the highest in the first quarter (January-March) and the fourth quarter (October-December) (P<0.05). The drug resistance test results showed that The drug resistance rates of diarrheogenic Escherichia coli and Salmonella to piperacillin/tazobactam, ceftazidime, imipenem and cefotaxime were relatively low (<30.00%). Conclusions The main pathogens causing diarrhea in Panzhihua City are Klebsiella, Salmonella, proteus, etc., and the multiple drug resistance is serious. The distribution of pathogens has obvious seasonal and age differences, so pathogen monitoring should be strengthened and effective measures should be taken to prevent and control the occurrence of drug resistance.
ABSTRACT
Objective To analyze the drug resistance phenotype and genetic background of New Delhi metallo-β-lactamase (NDM)-producing bacterial strains in Lishui area of Zhejiang province.Methods The imipenem-resistant Enterobacteriaceae strains were isolated from January 2012 to December 2016 in Lishui Municipal Central Hospital of Zhejiang Province.Mrieux Vitek 2 Compact system was used to identified strains and PCR was used to screen for blaNDMgene.Susceptibility was detected by K-B method and MICs were obtained by Vitek 2 with GN13 cards.Plasmids typing was carried out by DNA sequencing of the replication initiator with the transconjugates as templates.The blaNDMgenetic contexts were detected by PCR and complete genome sequencing.Results A total of 102 strains of carbapenem-resistant enterobacteria (CRE), mainly Escherichia coli and Enterobacter cloacae, were isolated, of which 15 were positive for blaNDMwith a positive detection rate of 14.7%.The resistance rate to β-lactam antibiotics was 100%, and the resistance rates to aztreonam, compound sulfamethoxazole , tobramycin and gentamicin were all ＞80%;and the resistance rate to quinolones was ＞50%.Among the 15 NDM-producing strains , 12 strains were positive for Hodge test, and 2 strains of Enterobacter cloacae and 1 strain of Escherichia coli were negative. There were 11 strains of blaNDM-1and 4 strains of blaNDM-1.A variety of plasmid types such as IncX 3, IncFIIγ and IncA/C were detected, and 4 blaNDM-5genes were located in the IncX3 plasmid.Four blaNDMsurrounding gene structures were found, of which 8 blaNDM-1genes were located in ISAb125-hyp-blaNDM-1-bleMBL-TrpF-DsbC-IS26, while blaNDM-5was located in IS3000-IS5-blaNDM-5-bleMBL-TrpF-DsbC-IS26 structure, and the former was reported for the first time in China.Conclusion NDM-producing bacterial strains in Lishui area are prevalent at a low level and have high sensitivity to fosfomycin and polymyxin .The blaNDMgene may have multiple sources, but IncX3 plasmid is still the main source for gene transfer.Some new types of blaNDM-1 gene structure have been also found in this study.