ABSTRACT
Objective To investigate the prevalence of plasmid-mediated quinolone resistance (PMQR) genes among clinical isolates of Klebsiella pneumoniae (K.pneumoniae) in pediatrics.MethodsA total of 131 non-duplicate clinical isolates of K.pneumoniae were collected in the Affiliated Children′s Hospital of Capital Institute of Pediatrics from 2010 to 2012.PMQR genes [qnrA, qnrB, qnrS, aac(6′)-Ⅰb-cr and qepA], mutations in the quinolone resistance-determining region (QRDR) and extended spectrum β-lactamases (ESBLs) genes in those strains were analyzed by PCR.Minimum inhibitory concentrations (MIC) of different antibiotics against those K.pneumoniae strains were determined by broth microdilution method and E-test according to the guidelines issued by the Clinical and Laboratory Standards Institute (CLSI).Transferability of the PMQR genes was examined by conjugation test with the sodiumazide-resistant Escherichia coli J53.Results Among the 131 isolates, 9.92% were resistant to quinolone and 30.5% were positive for PMQR genes, including 6.87% harboring qnrB gene, 22.9% harboring qnrS gene and 4.58% harboring aac(6′)-Ⅰb-cr gene.Neither qnrA-positive nor qepA-positive strain was detected.Among these PMQR genes-positive isolates, 90% were ESBLs-producing strains and two presented mutations in gyrA and parC genes.Conjugation test showed that these PMQR genes could be transferred horizontally and the ciprofloxacin resistance increased 2 to 32 folds in transconjugants.Conclusion This study indicates that the PMQR gene-carrying rate is high in K.pneumoniae strains isolated in paediatrics in China.Most of the PMQR gene-positive strains are also ESBLs-producing strains.The PMQR genes could be transferred horizontally in bacteria.
ABSTRACT
Mycoplasma pneumonia(MP) is a common cause of children community-acquired pneumonia,and can lead to a variety of extrapulmonary complications.Thus,a rapid,sensitive diagnostic method is particularly important for early diagnosis and treatment.As MP grows slowly,requires additional nutrient supply and easy to be contaminated by fungi and bacteria during the culture process,culture of MP might not be suitable for clinical detection.However,the PCR technique is more complicated and high requirement for operator to be implemented in primary hospitals.Therefore,the serum diagnosis has become the commonly used method in clinical diagnosis.This paper is to review the latest findings of different serological diagnostic methods,antigen component,and antibody type in different periods of infection of MP.