Variant O89 O-Antigen of E. coli Is Associated With Group 1 Capsule Loci and Multidrug Resistance

Abstract

Bacterial surface polysaccharides play significant roles in fitness and virulence. In Gram-negative bacteria such as Escherichia coli, major surface polysaccharides are lipopolysaccharide (LPS) and capsule, representing O- and K-antigens, respectively. There are multiple combinations of O:K types, many of which are well-characterized and can be related to ecotype or pathotype. In this investigation, we have identified a novel O:K permutation resulting through a process of major genome reorganization in a clade of E. coli. A multidrug-resistant, extended-spectrum β-lactamase (ESBL)-producing strain – E. coli 26561 – represented a prototype of strains combining a locus variant of O89 and group 1 capsular polysaccharide. Specifically, the variant O89 locus in this strain was truncated at gnd, flanked by insertion sequences and located between nfsB and ybdK and we apply the term O89m for this variant. The prototype lacked colanic acid and O-antigen loci between yegH and hisI with this tandem polysaccharide locus being replaced with a group 1 capsule (G1C) which, rather than being a recognized E. coli capsule type, this locus matched to Klebsiella K10 capsule type. A genomic survey identified more than 200 E. coli strains which possessed the O89m locus variant with one of a variety of G1C types. Isolates from our collection with the combination of O89m and G1C all displayed a mucoid phenotype and E. coli 26561 was unusual in exhibiting a mucoviscous phenotype more recognized as a characteristic among Klebsiella strains. Despite the locus truncation and novel location, all O89m:G1C strains examined showed a ladder pattern typifying smooth LPS and also showed high molecular weight, alcian blue-staining polysaccharide in cellular and/or extra-cellular fractions. Expression of both O-antigen and capsule biosynthesis loci were confirmed in prototype strain 26561 through quantitative proteome analysis. Further in silico exploration of more than 200 E. coli strains possessing the O89m:G1C combination identified a very high prevalence of multidrug resistance (MDR) – 85% possessed resistance to three or more antibiotic classes and a high proportion (58%) of these carried ESBL and/or carbapenemase. The increasing isolation of O89m:G1C isolates from extra-intestinal infection sites suggests that these represents an emergent clade of invasive, MDR E. coli.

Distribution of Hydrogen-Producing Bacteria in Tibetan Hot Springs, China

“…This finding implied that some rare populations in the environment may contribute more to the element cycle of the entire ecosystem. When we explore the relationship between microorganisms and environments, rare taxa cannot be ignored ( Zhang et al, 2018 ).…”

“…Total community DNA of the collected hot spring sediments were extracted with FastDNA Spin Kit according to the manufacturer’s instructions (MP Biomedicals, LLC, Solon, OH). Bacterial and Archaeal 16S rRNA genes were amplified with a universal primer set of 515F (5′GTGYCAGCMGCCGCGGTA-3′)/806R (5′-GGACTACVSGGGTATCTAAT-3′) according to the PCR conditions described previously ( Tamaki et al, 2011 ; Caporaso et al, 2012 ; Zhang et al, 2018 ). The hydA genes of the total community DNA in the collected hot spring sediments were PCR amplified using the primer set FeFe-272F (5′-GCHGAYMTBACHATWATGGARGA-3′, where H = A, C, T; Y = C, T; M = A, C; B = C, G, T; W = A, T; R = A, G; 432-fold degeneracy)/FeFe-427R (5′-GCNGCYTCCATDACDCCDCCNGT-3′, where N = A, C, T, G; Y = C, T; D = A, G, T; 864-fold degeneracy) ( Boyd et al, 2010 ; Sahl et al, 2011 ; Baba et al, 2014 ).…”

“…Tibetan hot springs are generally located at an elevation of over 4,000 m and receive fewer human perturbations, with a wide range of temperature from 22 to 94°C. Previous studies have investigated the compositions of total microbial communities and some functional microbial groups and their response to environmental variables in Tibetan hot springs ( Lau et al, 2006 , 2009 ; Lau and Pointing, 2009 ; Huang et al, 2011 ; Song et al, 2013 ; Wang et al, 2013 ; Wu et al, 2015 ; Yang et al, 2015 ; Zhang et al, 2018 ; Ma et al, 2021 ). The purpose of this study was to investigate the diversity of the HPB and their response to environmental factors in Tibetan hot springs.…”

Identification of Multiple Low-Level Resistance Determinants and Coselection of Motility Impairment upon Sub-MIC Ceftriaxone Exposure in Escherichia coli

“…These phenotypic changes may impact other processes such as virulence or horizonal gene transfer. Mucoid cells are associated with virulence ( 63 ), and OmpR regulates virulence in addition to outer membrane proteins ( 64 ); thus, besides resistance, there may be selection for host interaction effects. The link between motility and horizontal gene transfer, specifically plasmid conjugation, is less defined; however, data suggest that motility is reduced when conjugation of certain plasmids is prompted ( 65 ).…”

Antibacterial Activities of Ga(III) against E. coli Are Substantially Impacted by Fe(III) Uptake Systems and Multidrug Resistance in Combination with Oxygen Levels

“…A survey of strain genomes for relevant gene content was carried out as described previously, , and the used sequence resources are further described in Table S2.…”