title: Class 1 integrons in urinary isolates of extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae in Southern China during the past five years.
abstract: We analyzed extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (226) and Klebsiella pneumoniae (53) collected from urine specimens during 2005-2009 for the presence of ESBL genes, class 1 integrons, and characterization of gene cassettes. TEM and CTX-M β-lactamase genes were the most prevalent. One hundred and forty-four E. coli and 35 K. pneumoniae were positive for the class 1 integrase gene; among them, 99 E. coli and 14 K. pneumoniae detected gene cassettes. Gene cassette regions were identified by restriction fragment length polymorphism and DNA sequencing analysis. Eleven distinct gene cassette arrays were found in E. coli isolates, and seven distinct gene cassette arrays were found in K. pneumoniae isolates. The cassette array aacA4-catB8-aadA1 was first found in E. coli and dfrA1-orfC was first reported in K. pneumoniae. Most of the gene cassettes found in this class 1 integrons were for aminoglycoside resistance. Enterobacterial repetitive intergenic consensus-polymerase chain reaction fingerprint patterns revealed the isolates carrying gene cassettes were genetically unrelated. In conclusion, we studied the class 1 integrons among urinary isolates of ESBL-producing E. coli and K. pneumoniae in Southern China during the past 5 years and found that class 1 integrons were widely disseminated and played a major role in antibiotic resistance.
authors.affiliation: Laboratory Medicine Center, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Sun
authors.forename: Fen
authors.initials: F
authors.lastname: Zheng
authors.forename: Fengping
authors.initials: F
authors.lastname: Wang
authors.forename: Kuihai
authors.initials: K
authors.lastname: Wu
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.forename: Qing
authors.initials: Q
authors.lastname: Chen
authors.forename: Shouyi
authors.initials: S
authors.lastname: Yu
authors.forename: Yongyu
authors.initials: Y
authors.lastname: Rui
mesh_terms: D000617:Aminoglycosides / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002681:China; D004269:DNA, Bacterial / Q000145:classification / Q000235:genetics*; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000382:microbiology / Q000635:transmission / Q000652:urine; D006801:Humans; D019426:Integrases / Q000235:genetics* / Q000378:metabolism; D032023:Integrons; D007710:Klebsiella Infections / Q000188:drug therapy / Q000382:microbiology / Q000635:transmission / Q000652:urine; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D005810:Multigene Family; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D047090:beta-Lactams; D019426:Integrases; D001618:beta-Lactamases