Molecular Characterization and Correlation with β-lactam Resistance of Streptococcus pneumonia Isolates in Hangzhou,China

Penicillin-binding proteins（PBPs） are the target of β-lactam antibiotics（the major treatment for Streptococcus pneumoniae infections）,and mutations in PBPs are considered as a primary mechanism for the development of β-lactam resistance in S.pneumoniae.This study was conducted to investigate the mutations in the PBPs of clinical S.pneumoniae isolates in Hangzhou,China,in correlation with β-lactam resistance.Results showed that 19 F was the predominant serotype（7/27） and 14 of the S.pneumoniae isolates were resistant to both penicillin G and cephalosporin.Genotyping results suggested that β-lactam-resistant isolates primarily exhibited single-site mutations in both the STMK and SRNVP motifs of pbp1 a in combination with double-site mutations in the STMK motif of pbp2 x,which might be the primary mechanisms underlying the β-lactam resistance of the isolates in this study.

Usefulness of interferon-γrelease assay for the diagnosis of sputum smear-negative pulmonary and extra-pulmonary TB in Zhejiang Province,China

Background:Quick diagnosis of smear-negative pulmonary tuberculosis(TB)and extra-pulmonary TB are urgently needed in clinical diagnosis.Our research aims to investigate the usefulness of the interferon-γrelease assay(IGRA)for the diagnosis of smear-negative pulmonary and extra-pulmonary TB.Methods:We performed TB antibody and TB-IGRA tests on 389 pulmonary TB patients(including 120 smear-positive pulmonary TB patients and 269 smear-negative pulmonary TB patients),113 extra-pulmonary TB patients,81 patients with other pulmonary diseases and 100 healthy controls.Blood samples for the TB-Ab test and the TB-IGRA were collected,processed,and interpreted according to the manufacturer’s protocol.Results:The detection ratio of smear-positive pulmonary TB patients and smear-negative pulmonary TB patients were 90.8%(109 of 120)and 89.6%(241 of 269),respectively.There was no statistically significant difference of its performance between these two sample sets(P>0.05).The detection ratio of positive TB patients and extra-pulmonary TB patients were 90.0%(350 of 389)and 87.6%(99 of 113),respectively,which was not significantly different(P>0.05).Conclusions:In this work,the total detection ratio using TB-IGRA was 89.4%,therefore TB-IGRA has diagnostic values in smear-negative pulmonary TB and extra-pulmonary TB diagnosis.