Screen On MagA～+ Klebsiella Pneumoniae Strains And Clinical Analysis Of Corresponding Infected Patients

Klebsiella pneumoniae (Kp) is an important enteric gram-negative bacillus causing hospital-acquires infections which can change part of patients'lung structures and disseminative infections as seriously sequelae. The research on virulence factors is rising for preventing and controlling it. magA was found as a new virulence factors which could cause invasted and disseminative Kp infection. Although the pathogenic mechanism is not clear, magA has been used as a screening flag of high pathogenic Kp. Now no research has been reported about magA~+ Kp infection in mainland of China .PURPOSE: We want to study the magA~+ Klebsiella pneumoniae (Kp) strains exisit or not, and reveal the distribution. Then we will retrospectively analysis the clinic characteristics of magA~+ Kp infected patients to achieve some suggestion in diagnosis and therapy on Kp infection. This study will be helpful to establish a new rapid molecular diagnosis method for magA~+ Kp infection.METHODS: The 215 pathogenic Kp strains were isolated and identified from infected patients who visited Changhai hospital and No.85 military hospital from Jul 2006 to Jan 2007. Genomic DNA was extracted for polymerase chain reaction (PCR) to verify the magA gene existion. The positive control is NTHU-K2044 gene(Thank Dr.Wang, Taiwan national university). Corresponding clinical informations were collected at the same time for statistical analysis, such as general information, infected organs, number of invasited orgains, severity degree of infection, blood routine test, antibiotic, average time of therapy, drug resistance, prognosis and relapse rate. Statistical method: measurement data was described as X±D, t test was used for Gaussian distribution data, Wilcoxon rank sum test was used for nonnormal distribution data. Different count data was analysised by Cochran-mantel-haenszel statistic. Logistic gradual regressive analysis for predisposing factor of magA~+ Kp infection. Size of test was P<0.05.RESULTS: A total of 215 Kp infected patients and Kp strains were collected and detected. magA~+ Kp infections were found in Shanghai China. Positive rate was 13.8% which was higher than reported data. magA was significant correlative with hepatopostema(3/0). The male female ratio was 25/5, mean age was 6.91±19.69, respiratory infection was common(43.33%) and main complicaion was serous cavity effusion(20%) in magA positiveKp infected patiens group. There was significant difference between positive and negtived group in severity degree of infection, number of invasited orgains, average time of therapy, relapse rate and blood routine test. Logistic gradual regressive analysis showed that magA~+Kp infection was significant correlative with other bacterial infection(P=0.0255), time of therapy(P<0.0001) and number of invasited orgains. Drug resistances were same. Infected case was sporadic.CONCLUSION: Screen result by PCR verified the existence of magA~+ Kp strains. magA gene was significant correlative with hepatopostema. magA~+ Kp infection means worse severity degree, more time of therapy , easier disseminated infection and recidivation. PCR can be used as a rapid screen method for magA gene of clinical pathogenic Kp strains.