Complete Nucleotide Sequence of pK245, a 98-Kilobase Plasmid Conferring Quinolone Resistance and Extended-Spectrum-β-Lactamase Activity in a Clinical Klebsiella pneumoniae Isolate

Abstract

A plasmid containing the qnrS quinolone resistance determinant and the gene encoding the SHV-2 ␤-lactamase has been discovered from a clinical Klebsiella pneumoniae strain isolated in Taiwan. The complete 98-kb sequence of this plasmid, designated pK245, was determined by using a whole-genome shotgun approach. Transfer of pK245 conferred low-level resistance to fluoroquinolones in electroporant Escherichia coli epi300. The sequence of the immediate region surrounding qnrS in pK245 is nearly identical (>99% identity) to those of pAH0376 from Shigella flexneri and pINF5 from Salmonella enterica serovar Infantis, the two other qnrS-carrying plasmids reported to date, indicating a potential common origin. Other genes conferring resistance to aminoglycosides (aacC2, strA, and strB), chloramphenicol (catA2), sulfonamides (sul2), tetracycline (tetD), and trimethoprim (dfrA14) were also detected in pK245. The dfrA14 gene is carried on a class I integron. Several features of this plasmid, including three separate regions containing putative replicons, a partitioning-control system, and a type II restriction modification system, suggest that it may be able to replicate and adapt in a variety of hosts. Although no critical conjugative genes were detected, multiple insertion sequence elements were found scattered throughout pK245, and these may facilitate the dissemination of the antimicrobial resistance determinants. We conclude that pK245 is a chimera which acquired its multiple antimicrobial resistance determinants horizontally from different sources. The identification of pK245 plasmid expands the repertoire of the coexistence of quinolone and extended-spectrum-␤-lactam resistance determinants in plasmids carried by various species of the family Enterobacteriaceae in different countries.Plasmid-mediated quinolone resistance was first identified in a clinical Klebsiella pneumoniae strain in the United States in 1998 (29). The gene responsible for this mechanism, qnrA, was later characterized (43). Several QnrA-and QnrB-like proteins have since been identified in different species of the family Enterobacteriaceae, including Escherichia coli, Enterobacter cloacae, and K. pneumoniae from the United States, Europe, and Asia (6,21,22,27,32,36,37,44,45). Another qnr gene, qnrS, was recently found on a transferable plasmid from a clinical Shigella flexneri isolate in Japan (19) and has subsequently been found in a Salmonella enterica serovar Infantis isolate of avian origin (23). Although many qnrA-and qnrB-positive plasmids were also found to carry genes encoding extended-spectrum ␤-lactamases (ESBLs) (21, 32, 34), no ESBLs were found on the plasmids that carried qnrS.We recently identified a multidrug resistance plasmid from K. pneumoniae strain NK245. NK245 was isolated in January 2002 from a patient with hospital-acquired urinary tract infection. The plasmid, designated pK245, conferred resistance to several classes of antimicrobials in the E. coli electroporant, including low-level resistance to fluoroquinolones (FQs). The...

Carbapenem-Resistant Klebsiella pneumoniae Strains Exhibit Diversity in Aminoglycoside-Modifying Enzymes, Which Exert Differing Effects on Plazomicin and Other Agents

“…The high prevalence of AAC(6=)-Ib is likely explained by the fact that the vast majority of our carbapenem-resistant K. pneumoniae isolates possessed ESBLs, as genes for AAC(6=)-Ib and ESBLs are known to localize to the same plasmid (32,33). In general keeping with our findings, previous studies have reported that AAC(6=)-Ib affects tobramycin and amikacin susceptibility, while sparing gentamicin (34).…”

Unexpected Occurrence of Plasmid-Mediated Quinolone Resistance Determinants in EnvironmentalAeromonasspp.

“…The qnrS1 gene has been identifi ed now from several enterobacterial isolates from Japan (9), Germany (28), the United Kingdom (29), the United States (25), France (17), Vietnam (30), Taiwan (31,32), and Denmark (33). The qnrS2 gene (92% amino acid identity with QnrS1) was identifi ed from a transferable IncQ-related plasmid (pGNB2) isolated from an activated sludge bacterial community of a wastewater treatment plant in Germany (24) and in a single non-Typhi Salmonella clinical isolate from the United States (25).…”

The evaluation of resistance genes and gene mutations in quinolone resistant Escherichia coli and Klebsiella spp. isolates

“…Güven Ö (27) , sağlıklı çocukların dışkılarında kinolon dirençli E. coli taşıyıcılığı ve direnç mekanizmalarını saptamak amacıyla yaptığı araştırmada, kinolon direnci saptadığı 15 E. coli izolatında qnr geni saptamamıştır. Avrupa'daki çalışmalarda (31,33,45) , genellikle qnrS ve qnrB genleri baskın görülmekle birlikte, İngiltere'de yapılmış olan bir çalışmada (46) , qnrA geni, İspanya'da yapılmış olan bir çalışmada (36) ise, qnrA1 geni yüksek oranda belirlenmiştir. Türkiye'de E. coli ve Klebsiella spp.…”