open access

Vol 50, No 1 (2012)
Original paper
Submitted: 2012-04-24
Accepted: 2012-04-24
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Characteristics of Klebsiella pneumoniae harboring QnrB32, Aac(6’)-Ib-cr, GyrA and CTX-M-22 genes

Dongguo Wang, Haibao Wang, Yongxiao Qi, Yong Liang, Jin Zhang, Lianhua Yu
DOI: 10.5603/FHC.2012.0009
·
Folia Histochem Cytobiol 2012;50(1):68-74.

open access

Vol 50, No 1 (2012)
ORIGINAL PAPERS
Submitted: 2012-04-24
Accepted: 2012-04-24

Abstract

Quinolone resistance in members of the Enterobacteriaceae family is mostly due to mutations in the quinolone resistance-determining regions of topoisomerase genes. CTX-M-22 is a member of the CTX-M family which can reduce extended-spectrum β-lactamase (ESBL) production and modulate antibiotic resistance, resulting in low ceftazidime minimum inhibitory concentrations (MICs). There are four different genes in Klebsiella pneumoniae (KP4707) including qnrB32 (novel qnr allele gene, HQ704413), aac(6’)-Ib-cr (novel aac(6’)-Ib allele gene, HQ680690), gyrA (novel gyrA allele gene, HQ680691) and CTX-M-22 gene. Five point amino acid mutations Arn(N)27 → Leu(L), Val(V)129 → Ala(A), Iie(I)142 → Met(M), Gly(G)188 → Arg(R), Val(V)212 → Iie(I) were observed in the qnr32 gene when compared to qnrB1. Of all qnrB alleles, a novel variant of the qnrB32 gene, with qnrB31, had the highest amino acid homology. Three point amino acid mutations including Trp(W)105 → Arg(R), Asp(D)182 → Tyr(Y) and Val(V)201 → Asp(D) were observed in aac(6’)-Ib-cr gene, when compared to GenBank number AF479774. New variants of qnr32, aac(6’)-Ib-cr, gyrA and CTX-M-22 or other genotype determinants continuously appear in different genomic sites and also outside the Enterobacteriaceae family.

Abstract

Quinolone resistance in members of the Enterobacteriaceae family is mostly due to mutations in the quinolone resistance-determining regions of topoisomerase genes. CTX-M-22 is a member of the CTX-M family which can reduce extended-spectrum β-lactamase (ESBL) production and modulate antibiotic resistance, resulting in low ceftazidime minimum inhibitory concentrations (MICs). There are four different genes in Klebsiella pneumoniae (KP4707) including qnrB32 (novel qnr allele gene, HQ704413), aac(6’)-Ib-cr (novel aac(6’)-Ib allele gene, HQ680690), gyrA (novel gyrA allele gene, HQ680691) and CTX-M-22 gene. Five point amino acid mutations Arn(N)27 → Leu(L), Val(V)129 → Ala(A), Iie(I)142 → Met(M), Gly(G)188 → Arg(R), Val(V)212 → Iie(I) were observed in the qnr32 gene when compared to qnrB1. Of all qnrB alleles, a novel variant of the qnrB32 gene, with qnrB31, had the highest amino acid homology. Three point amino acid mutations including Trp(W)105 → Arg(R), Asp(D)182 → Tyr(Y) and Val(V)201 → Asp(D) were observed in aac(6’)-Ib-cr gene, when compared to GenBank number AF479774. New variants of qnr32, aac(6’)-Ib-cr, gyrA and CTX-M-22 or other genotype determinants continuously appear in different genomic sites and also outside the Enterobacteriaceae family.
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Keywords

Klebsiella pneumoniae; qnrB32; aac(6’)-Ib-cr; gyrA; CTX-M-22

About this article
Title

Characteristics of Klebsiella pneumoniae harboring QnrB32, Aac(6’)-Ib-cr, GyrA and CTX-M-22 genes

Journal

Folia Histochemica et Cytobiologica

Issue

Vol 50, No 1 (2012)

Article type

Original paper

Pages

68-74

DOI

10.5603/FHC.2012.0009

Bibliographic record

Folia Histochem Cytobiol 2012;50(1):68-74.

Keywords

Klebsiella pneumoniae
qnrB32
aac(6’)-Ib-cr
gyrA
CTX-M-22

Authors

Dongguo Wang
Haibao Wang
Yongxiao Qi
Yong Liang
Jin Zhang
Lianhua Yu

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