Analysis Of Antibiotic-resistant Pathogens And Related Factors For Ventilator-associated Pneumonia In ICU

Objective:Ventilator-associated pneumonia(VAP) is the leading ICU infection, the frequency of VAP caused by multiantibiotic-resistant pathogens has increased in recent years, VAP has increased the length of ICU stay and costs of treatment. Pathogens, antibiotic resistance and clinically related factors in VAP were explored to provide the corresponding clinical prevention strategies. Methods: The clinical data of all the 97 mechanical ventilation(>48h) patients admitted to our comprehensive ICU from July 2002 to december 2003 were retrospectively investigated, and all the 97 patients were divided into two groups:VAP and non-VAP. The micro-organism data of all the 39 VAP patients was analysed. Aspsis tube or bronchofibroscope was used to obtain secretions from lower respiratory tract, The specimens were cultivated and examed drug-resistance . Using univariate analysis of a statistical software package(SPSS11.5) we first analysed the related prognostic factors of VAP( including age, sex, mechanical ventilation days, ICU stay, shock, antibiotic usage 48h before ventilation , corticosteroid usage, trauma, operation, Glasgow coma score, acute physiology and chronic health evaluation [APACHEⅢ] and the effect of VAP to mortality),then independent risk factors were determined with backward multivariate stepwise logistic regression analysis. Results: The morbidity of VAP was 40.2% and the mortality was 61.5%, A total of 211 pathogens were identified. Among all the strains causing VAP, Gram-negative bacteria accounted for 80.1%, in which Pseudomonas aeruginosa was the major pathogen. Gram positive cocci occuping 9.5% and 10.4% were fungi. Extened-spectrum β-lactamases-producing strains were identified in Enterobacter aerogen, Klebsiella pneumoniae, Enterobacter cloacae and Escherichia coli. All these indicated high resistant rate to commonly used antibiotics in Gram-negative bacteria. Univarite analysis showed that the number of days of mechanical ventilation, ICU stay, antibiotic usage 48h before ventilation, COPD, corticosteroid usage, Glasgow coma score, APACHEⅢ were significant related with VAP and mortality is also connected with VAP. While mutivarite stepwise logistic regression analysis showed that mechanical ventilation days, antibiotic usage 48h before ventilation and APACHEⅢ were independent risk factors. The relative risk and 95% confidencial interval of mechanical ventilation days, antibiotic usage 48h before ventilation and APACHEⅢ were: 1.158(1.072~1.251), 9.405(2.065~42.836), 1.032(1.011~1.052) respectively. Conclusion: Gram-negative bacteria were the most common pathogens of VAP in central ICU , which presented to multi-drug resistant pattern. The morbidity and mortality of VAP were very high , VAP was related with many clinical factors. To effectively control VAP, extensive and dynamical monitoring of VAP pathogens and avoiding of related factors were advocated.