The Bacterial Diversity And Antibiotic Resistance In Burn Department

OBJECTIVE: 1. To explore the distribution and dug susceptibility of pathogens causing infections of the patients in the burn department by using the statistical methods so as to guide reasonable use of antibiotics and control bacterial infection effectively. 2. To analyze the composition of bacterial community and it’s dominant flora in burn department by building the 16 S r RNA gene library of bacterium so as to prevent and control infection effectively and reduce hospital acquired infection.METHODS: 1. To analyze retrospectively the distribution characteristic and anibiotic resistant status of bacterium with positive bacterial culture in burn department by using the software of WHONET from Jan 2011 to Dec 2013. 2. To use 16 S r RNA gene sequencing approach to investigate the bacterial diversity. Total microbial DNA was directly extracted from the environmental samples of burn department. The clone library of 16 S r RNA genes was amplified using PCR with universal bacterial primers sets. Each unique restriction fragment polymorphism pattern,created by using two restriction endonucleases(Hha I and Rsa I), was designated as an operational taxonomic unit(OUT). Amplified DNA was sequenced for bacterial diversity analysis.RESULTS: 1. A total of 1833 clinical specimens were cultured in burn department from Jan 2011 to Dec 2013, there were 1496 wound secretion(81.6%), 65 respiratory specimens(3.7%), 34 Catheter samples(1.8%), 191 blood samples(10.4%), 6 urine samples(0.4%), 28 abscess fluid samples(1.5%) and the other 39 samples(2.1%).A total of 2587 strains of pathogens were isolated from the patients of the burn department, there were 1728(66.8%) strains of gram-positive bacterium, among which the top three highest isolated pathogens were Staphylococcus aureus(S.aureus), Staphylococcus epidermidis(S.epidermidis) and Enterococcus faecalis(E.faecalis), accounting for 21.5%, 9.4%, 6.5%,respectively;there were 832(32.1%) strains of gram-negative bacterium,among which the top three isolated species were Enterobacter cloacae(E.cloacae), Acinetobacter baumannii(A.baumannii) and Escherichia coli(E.coli), accounting for 9.3%, 6.4%, 5.2%, respectively; there were 27(1.1%) strains of fungi, among which the main pathogens was Candida albicans. 2. The main pathogens were Gram-positive bacteria in clinical isolated pathogens of burn department, followed by Gram-negative bacteria. In Gram-positive bacterium, the antibiotic resistance rates of the S. aureus to most antimicrobials were more than 70.0%; the drug resistance rates of the S. epidermidis to most antimicrobial were more than 40.0%. In Gram-positive bacterium, the antibiotic susceptibility rates of the E. cloacae to ampicillin, cefazolin, piperacillin, cefoxitin and compound sulfamethoxazole were 62.9%,100%,37.5%,100%,98.3%,respectively; the antibiotic resistance rates of the A. baumannii to most antimicrobials were over 60%; the antibiotic susceptibility rates of the E. coli to ampicillin, amikacin, levofloxacin were 91.8%, 4.1%, 56.8%, respectively. 3. Bacterial communities on the floor at burn department including α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, Actinobacteria and Firmicutes; bacterial communities on the door handle including α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, Bacteroidetes and Actinomycetes; bacterial communities on the windowsill including α-Proteobacteria, β-Proteobacteria, Deinococcus-Thermus, Bacteroidetes and Firmicutes; bacterial communities on the bed railings including β-Proteobacteria, γ-Proteobacteria, Actinomycetes, Firmicutes and Deinococcus-Thermus. Compared with the environment out burn department,the bacterial diversity and structure is clearly different from it in nature. 4. The main pathogens isolated from the ward of burn department were S. aureus and S. epidermidis, and all the S. aureus isolated were resistant to methicillin, S. epidermidis were sensitive to most antibiotics.CONCLUSIONS: 1. The main type of clinical specimens from burns department was the wound secretions, fllowed by the blood. There are a variety of infection in the patients of burn department, the main pathogens was S. aureus、S. epidermidis and E.cloacae.The antibiotic resistance rates of the pathogens to the commonly used antibiotics in the burn department are high, and most strains showed multidrug-resistance. Therefore, it is necessary to strengthen the monitoring of the drug resistance and guide the use of antibiotics. 2. The main pathogens isolated from the ward environment of burn department were S. aureus and S. epidermidis, and all the S. aureus isolated were resistant to methicillin. The clinical should strengthen routine disinfection, and take effective measures to prevent hospital acquired infection. 3. The environment of burn department was particular, it may act as filters velecting specific bacterial populations and creating special areas where microbiota clearly differs from that present in nature.It needs pay more attention to.The bacterial community structure and diversity were different inside and outside burn department.It should be pay more attention to the sanitation management of health care workers, and to take relevant disinfection measures, at the same time strengthen the monitoring.