Analysis of the drug-resistant characteristics of Klebsiella pneumoniae isolated from the respiratory tract and CTX-M ESBL genes

• Published in: Genetics and molecular research Vol. 14; no. 4; pp. 12043 - 12048
• Main Authors: Huang, S Y, Pan, K Y, Liu, X Q, Xie, X Y, Dai, X L, Chen, B J, Wu, X Q, Li, H Y
• Format: Journal Article
• Language: English
• Published: Brazil 01.01.2015
• Subjects: beta-Lactamases - genetics; Drug Resistance, Bacterial; Humans; Klebsiella pneumoniae; Klebsiella pneumoniae - drug effects; Klebsiella pneumoniae - enzymology; Klebsiella pneumoniae - genetics; Klebsiella pneumoniae - isolation & purification; Respiratory Mucosa - microbiology
• ISSN: 1676-5680; 1676-5680
• DOI: 10.4238/2015.october.5.17

The main aim of this study was to understand the relationship between the drug-resistant characteristics of Klebsiella pneumoniae and CTX-M-type extended spectrum β-lactamases (ESBLs), and to detect the distributions of CTX-M-type ESBLs in clinically isolated strains. CTX-M ESBL genes isolated from the clinical samples were amplified by polymerase chain reaction and identified by sequence analysis; the antibiotic susceptibility of the samples was determined using the Kirby-Bauer disc-diffusion method. One hundred and five strains among the 246 isolated strains of K. pneumoniae tested positive for ESBL production (42.68%); 92 of these produced CTX-M ESBLs. Of the 92 CTX-M ESBL strains, 81 produced CTX-M-1 ESBLs and 11 produced CTX-M-25 ESBLs. Fifty-seven of the CTX-M-1 ESBL- and six of the CTX-M-25 ESBL-producing bacteria had CTX-M ESBL genes that coexisted in the plasmid and chromosome. The Kirby-Bauer antibiotic susceptibility method revealed that CTX-M ESBL-positive strains showed a higher rate of resistance to cefazolin, cefoxitin, cefuroxime, ceftazidime, cefotaxime, aztreonam, levofloxacin, and cotrimoxazole, compared to the CTX-M ESBL-negative strains (P < 0.05). The CTX-M ESBL genes were commonly observed in the K. pneumoniae isolated from respiratory tract samples; these were significantly associated with the drug-resistant characteristics of K. pneumoniae to β-lactam antibiotics.