Study On Etiologic Characters Of The Central Nervous System Infections And Bacterial Drug Resistance

Objective To characterize the epidemiology of etiologic factors and antibiotic bacterial drug resistance for central nervous system infections, and investigate drug susceptibilitys and resistant mechanism of present clinical isolates. Methods Retrosepective cohort study with patients of central nervous system infections identified, admitted between January 1983 and December 1999 to The First Affiliated Hospital, Anhui Medical University. Trend of etiology and antibiotic susceptibility were analysed; The clinical isolates from specimens of urine,sputum,peritoneal fluid,wound,abscess/pus,prostatic fluid,blood .etc of the whole hospital patients from March 1999 to March 2000 were identified and tested the drug resistance to antimicrobial agents by MicroScan WalkAway-40. ESBLs and TB producing strains in gram negative bacilli were detected by double disc synergy test and dilution test respectively, MRSA and MRSE were detected by agar dilution test . Results in 283 cases of organisms reported , bacterial meningitis, fungi meningitis,tubercular meningitis were 249 cases(88.0%), 22(7.8%), 12(4.2%) respectively. The main causative agents of the community acquired bacterial meningitis were N. rneningltidis(3 3.1%), S.aureus( 14.1%) , S. pneumoniae(7.2%), but common pathogenic bacterium of 24 cases of the nosocomial bacterial meningitis were K.pneumoniae(22.2%),P.aeruginosa(l 1.1%), S.aureus(l 1.1%). Penicillin resistance in pneumOcOcCLlS was 7.7% (1/13) , penicillin resistance in the menigococcus was 11.1% (3/27) , MRSA was 25% (6/24) , resistance to third-generation cephalosporins was found in most of gram negative bacilli, and it indicated that rate of resisrtance to aminoglycosides in gram negative bacilli was higher, especially to gentamicin andkanamycin; In productivity rate of extended spectrum beta-lactamases (ESBLs) by gram negative bacilli of present clinical isolates to the third generation cephalosporins , K.pneumoniae was 35.O%~?6.9%, E.coli 21.8%?3.O%, and in productivity rate of inducible beta-lactamases(IB) to common bata-lactam antibacterials, P.aeruginosa was 5l%-~-6O.9%, C.freundii 4.5%~63.6%, E.cloacae 8.7%~?5.3%. The staphlococcus resistant to penicillin counted for 92.7%棐98.9%, S.aureus resistant to oxacillin (MRSA) was 39%, S.epidermidis resistant to oxacillin (MRSE) was 73.1%. Conclusions The organisms of the community acquired bacterial meningitis were significantly different from the nosocomial bacterial meningitis . The incidence of opportunistic pathogen, fungi, tubercle bacilli and nosocomial infections in central nervous system infections has been increasing over the past 5 years, and N. meningitidis, S.aureus, S. pneumoniae which were common organisms of community acquired bacterial meningitis has a decreasing trend, and antimicrobial resistance has emerged among the three majaor bacterial pathogens causing meningitis. In treatment of bacterial meningitis ,penicillin remains the first-line antibiotics against NM and SP, while vancomycin(or rifampicin) with the third generation cephalosprins(cefotaxime or ceftriaxone) should be the first choice to treat MRSA or MRSE and penicillin resistance in SP, meropenem or imipenem should be regarded as the optimal choice to gram negative bacilli resistance to third generation cephalosporins; The production of ES払Ls and lB was the main mechanism of gram negative bacilli of present clinical isolates resistance to bata-lactam antibacterials,and imipenem alone or cefoperazone/sulbactam with amikacin or fluoroquinolones should be regard as the first-line antibiotics in treatment of non nervous system nosocomial infections.