title: Antibiotic resistance and molecular epidemiology of the beta-lactamase-producing Haemophilus influenzae isolated in Chongqing, China.
abstract: This study aimed to determine the antibiotic resistance and molecular epidemiology of Haemophilus influenzae isolated from children with acute respiratory infection in Chongqing, China. To this end, 1967 H. influenzae isolates from 2006 to 2009 were analysed regarding β-lactamase production and antibiotic resistance. Ninety-nine β-lactamase-producing H. influenzae isolates from 2010 were analysed for antibiotic resistance and promoter regions of bla(TEM) (-1) . β-lactamase production was found in 35.8% (705/1967) of the strains. All ninety-nine β-lactamase-producing strains from 2010 were of the TEM-1 type as determined by PCR but did not produce the predicted 1075 bp product. According to PCR-SSCP and DNA sequencing, the promoter regions of bla(TEM) (-1) were categorized into 6 genotypes as SSCP1 (Pdel), SSCP2 (Pa/Pb), SSCP3 (P4), SSCP4 (Prpt.b), SSCP5 (2Prpt) and SSCP6 (P3.b). The Pdel, Pa/Pb and Prpt.b were common promoters of bla(TEM) (-1) for H. influenzae isolated from children in Chongqing. Strains with Prpt.b were more resistant to ampicillin (AMP) than strains with Pdel, Pa/Pb and P4 (p < 0.05). Therefore, bla(TEM-1) β-lactamase is the main mechanism for resistance of H. influenzae to ampicillin in Chongqing. Furthermore, the Prpt.b promoters may be related to the high resistance of H. influenzae to AMP.
authors.affiliation: Department of Kidney and Immunology, Ministry of Education Key Laboratory of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Chong
authors.initials: C
authors.lastname: Luo
authors.forename: Yongwu
authors.initials: Y
authors.lastname: Xia
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.forename: Lijuan
authors.initials: L
authors.lastname: Chu
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Fu
authors.forename: Chunmei
authors.initials: C
authors.lastname: Jing
authors.forename: Dapeng
authors.initials: D
authors.lastname: Chen
authors.forename: Lan
authors.initials: L
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Shi
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D000668:Ampicillin Resistance / Q000235:genetics*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001483:Base Sequence; D002648:Child; D002681:China / Q000453:epidemiology; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification*; D006192:Haemophilus Infections / Q000453:epidemiology* / Q000382:microbiology; D006193:Haemophilus influenzae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000382:microbiology; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D000667:Ampicillin; D001618:beta-Lactamases