A Correlation Study Between Resistance to Gram Negative Strain and Application of Clinical Antibiotics in Newborns with Pneumonia

Objective To study the relationship among the production of extend -spectrum β-lactamases (ESBLS) ,the resistance to twelve antibiotics and application of clinical antibiotics. Methods Sputum specimen from newborns who were diagnosed as infective pneumoniae were collected. The specimen were cultured on fresh blood agar and high osmolar agar .The bacteria were quickly identified by an automated system combined with API system .A K-B test analysed the antimicrobial susceptibility and a double disk test detected ESBLS in the isolated gram negative (Gˉ) bacteria . The application of antibiotics in patients was investigated before ESBLS were detected. Results Four hundred and twenty-eight ( 19.8% ) strains of Gˉ bacteria were gained from the 2 164 specimen. In the 428 strains, 306 (71.5%) were from Enterobacteriaceae, 83 (19.4%) of the 428 strains were ESBLS. Seventy-eight (25.5%) strains of ESBLS were from Enterobacteriaceae. The resistant rate of IPM was the lowest in the twelve antibiotics. CIP, CAZ and AMK also had low resistant rate. The percentage of using any antibiotics and using the third generation cephalosporins before detection in patients infected with ESBLS strains was 97.6% (81/83),63.9%(53/83) respectively,which was significantly higher than those in patients who were infected with non-ESBLS[69.3% (239/ 345 ), 18.0% (62/345)].The difference was significant between the two groups (P0.005) . Conclusions The application of antibiotics ,especially the using of the third generation cephalosporins is a risk factor of producing ESBLS .IPM is the best drug to treat patients infected with ESBLS.