Association of Tellurite Resistance with Hypervirulent Clonal Groups of Klebsiella pneumoniae

Abstract

Tellurite-based selective growth media are used for several bacterial pathogens. We found that, in Klebsiella pneumoniae, tellurite resistance is strongly associated with hypervirulent clonal group 23 (CG23), CG65, and CG86, providing a novel approach for screening environmental or carriage samples. The terW gene was also associated with these groups. Klebsiella pneumoniae is an important pathogen that poses increasingly severe therapeutic challenges due to the continuous emergence of multidrug-resistant strains (1, 2). In parallel, severe invasive infections typically acquired in the community are increasingly reported and collectively regarded as being caused by hypervirulent K. pneumoniae (hvKP) strains (3). Multidrug-resistant and hypervirulent K. pneumoniae isolates represent largely nonoverlapping populations (4) and belong predominantly to a few clonal groups (CGs), such as CG23 associated with liver abscess (5-7) and CG258 associated with production of the K. pneumoniae carbapenemase (KPC) (8,9). A better understanding of the epidemiological reservoirs of high-risk (i.e., multidrug-resistant or hypervirulent) K. pneumoniae clonal groups is needed to control their dissemination. Selective media that are used to screen environmental sources or animal and human fecal samples for the presence of K. pneumoniae include the MacConkey-inositol-potassium tellurite (MCIK) medium (10) and the Simmons citrate agar with inositol (SCAI) medium (11). While these media rely on the ability of K. pneumoniae strains to utilize inositol (12)(13)(14), the MCIK medium selects for resistance to tellurite (10), whereas the SCAI medium relies on the ability of K. pneumoniae isolates to also utilize citrate (11). Interestingly, tellurite resistance is found in several bacterial pathogens, including Yersinia pestis, Shigella, and enterohemorrhagic Escherichia coli (15)(16)(17). Recently, tellurite resistance in Bacillus anthracis was linked to resistance against host defenses and to pathogenesis (18). A prominent feature of hvKP strains is the presence of a large virulence plasmid, pLVPK (19-21), which harbors the tellurium resistance genes terZABCDE and terW. The terW gene rescues E. coli cells from the toxic effect of terZABCDE (22). The purpose of this study was to investigate the distribution of tellurite resistance among K. pneumoniae clonal groups.A total of 154 isolates was selected to cover the known breadth of phylogenetic diversity of K. pneumoniae and related species (Table 1). First, we included 123 strains belonging to K. pneumoniae sensu stricto, i.e., to phylogroup KpI (23,24). These strains were taxonomically classified by multiple gene sequencing (24,25) and comprised 120 strains of K. pneumoniae subsp. pneumoniae, two strains of K. pneumoniae subsp. rhinoscleromatis, and one strain of K. pneumoniae subsp. ozaenae. The 123 K. pneumoniae strains were selected to represent a diverse set of clonal groups (4), as approximated by their sequence type (ST). A total of 38 strains of ST23, ST65, ST86, ST375, and ST380, whi...

Tracking key virulence loci encoding aerobactin and salmochelin siderophore synthesis inKlebsiella pneumoniae

“…False positive detection of the aerobactin locus version of iutA can be avoided by using an identity threshold of <20% divergence. Tellurite resistance has also been suggested as a phenotypic screen to identify hypervirulent isolates of CG23, CG65 and CG86(55); our data confirms this is a good marker for KpVP-1 (92.6% carry ter ), but not for other aerobactin plasmid types (Table S10).…”

High Prevalence of ESBL-Producing Klebsiella pneumoniae Causing Community-Onset Infections in China

“…Especially, ST86 was the most abundant clone among CTX-M-15 producers in this study, and is known to correlate to invasive infections such as bacteraemia, pneumonia with septic shock and liver abscess (Bialek-Davenet et al, 2014; Liao et al, 2014; Passet and Brisse, 2015). In this study, five of seven ST86 strains were isolated from sputum of children (aged from 15 days to 3 years) with community-acquired respiratory tract infections, and the other two were isolated from liver abscess and blood in adult patients.…”

Klebsiella variicola and Klebsiella quasipneumoniae with capacity to adapt to clinical and plant settings

“…30 Tellurite resistance is needed to colonize macrophages. 31 The TerABCDEWXYZ proteins cluster was identified in 12.9% (4/31) and 12.5% (1/8), of K. variicola and K. quasipneumoniae, all of human origin.…”