An Epidemiological Study Of Nosocomical Infection By Extended-spectrum Beta-Lactamase-producing Bacteria

Objective:To investigate the hospital patients infected by extended-spectrum beta-lactamase(ESBLs ) -producing bacteria and their drug-resistence; and study the risk factors of nosocomial infection induced by ESBLs -producing bacteria, to provide a reasonable proofs for hospitals of preventing and controlling nosocomial infection by ESBLs -producing bacteria. Methods :1. Bacterial culture was performed with routine method: The separated germs were ap - praised with the bacterial analysis system. The affirmation of ESBL s and the drug sensitivity tests to the separated germs were processed with paper diffusionmethod(Kirby-Bauer single disc-diffusion)according to NCCLs.2. By case-control study,rerospective study of the clinicaldata of cases with hospital aquired infection by positive- ESBLs bacteria and those of negative- ESBLs bacteria by non-conditional logistic regression analysis from 2000 to 20030 Data were analyzed with chi-square test and unconditional logistic regression. Results:1. The average positive rate of ESBLs-producing bacteria in 1650 gram-negative germs was 11.2% .Among them, the ratio of Escherichia coli, Klebsiella pneumoniae, Enterobacter colacae were29.7%, 42.2%, and 10.8% respectively. The drug sensitivity tests showed that the germs which produce ESBL shad a high sensitive to imipenem , but a high resistantance to cefoxitin, aminoglycosides, and quinolones. these germs were multi-4resistant to commonly used antibiotics such as ceftazidime, ,aztreonam, and aminoglycoside antibiotics. Compared with other bacteria , the resistance to antibiotic of the patients caused by ESBLs bacteria is remarkable higher.2. the clinical characteristics of the patients infected by ESBLs - producing bacteria: Among 185 ESBLs-producing bacteria, the ratio of ESBLs-producing bacteria in different groups of age was different.. The positive rate of ESBLs-producing in Respiratory ward and ICU was more significant than other wards. It is not statistically significant among the paitients of different basical diseases.3. Influencing factors: Multivariate unconditional logistic regression analysis showed that the risk factors leading to hospital-acquired infection by ESBLs -producing bacteria included: the time in hospital over 14 days, using third generation cephlosporins over seven days, presence of catheters and oxygen inhalation. Conclusions:Nosocomial infection induced by ESBLs -producing bacteria could attribute to multiple factors, mainly to unreasonable use of antibioticsand and adrenal cortical hormone, long time in hospital and oxygen inhalation. The medical laboratory should pay great attention to monitor and to control the spread of ESBLs germs in hospital and use the antibiotic rationally. Imipenem is effective to ESBL s germs.