Serogroups and virulence genotypes of Escherichia coli isolated from patients with sepsis

Abstract

Sixty strains of Escherichia coli, isolated by hemoculture, from septicemic Brazilian patients were evaluated to determine their serogroup and invasivity to Vero cells. All 60 patients died within 2 days of hospitalization. Furthermore, the molecular study of the following extraintestinal pathogenic E. coli-associated virulence factor (VF) genes was performed by PCR: i) adhesins: type 1 fimbria (fimH ), S fimbria (sfaD/E ), P fimbria (papC and papG alleles) and afimbrial adhesin (afaB/C ); ii) capsule K1/K5 (kpsMTII ); iii) siderophores: aerobactin (iucD), yersiniabactin (fyuA) and salmochelin (iroN ); iv) toxins hemolysin (hlyA), necrotizing cytotoxic factor type 1 (cnf1 ) and secreted autotransporter toxin (sat ); v) miscellaneous: brain microvascular endothelial cells invasion (ibeA), serum resistance (traT ), colicin V (cvaC ) and specific uropathogenic protein (usp). Our results showed that isolates are able to invade Vero cells (96.6%), differing from previous research on uropathogenic E. coli (UPEC). The O serogroups associated with UPEC were prevalent in 60% of strains vs 11.7% of other serogroups. The PCR results showed a conserved virulence subgroup profile and a prevalence above 75% for fimH, fyuA, kpsMTII and iucD, and between 35-65% for papC, papG, sat, iroN, usp and traT. The evasion from the immunological system of the host and also iron uptake are essential for the survival of extraintestinal pathogenic E. coli strains. Interestingly, among our isolates, a low prevalence of VF genes appeared. Therefore, the present study contributes to the identification of a bacterial profile for sepsis-associated E. coli.

Inhibition of P2X Receptors Protects Human Monocytes against Damage by Leukotoxin from Aggregatibacter actinomycetemcomitans and α-Hemolysin from Escherichia coli

“…It must be stressed that the pharmacological approach is the most favorable way of addressing P2Y 2 protein expression because of the quality of the antibodies. Since several of the P2Y receptors shown to be expressed in the THP-1 cells by mRNA are G xq coupled, we tested whether interference with phospholipase C (PLC) activation and the inositol trisphosphate (IP 3 ATP immediately upon insertion into plasma membranes and THP-1 monocytes express several functional P2 receptors, we expect HlyA to trigger a [Ca 2ϩ ] i response in THP-1 monocytes. Therefore, we exposed fluo-4-AM-loaded THP-1 monocytes to HlyA, which concentration-dependently increased [Ca 2ϩ ] i ( Fig.…”

“…-Hemolysin (HlyA) is an important virulence factor frequently produced by strains of pathogenic Escherichia coli (1)(2)(3). The frequency with which HlyA-producing E. coli strains are isolated from patients increases with severity of the disease (for a review, see reference 2).…”

Characterization of the extra-intestinal pathogenic Escherichia coli ST131 clone among isolates recovered from urinary and bloodstream infections in the United Kingdom

“…However, our ST131-O16 isolates lacked the pabB SNPs specific to this clone and likely represent single-locus variants of ST131 within the larger clonal complex, which have been detected here where other molecular assays have failed to do so . By contrast the novel serogroups may have emerged by high-frequency recombination with other E. coli pathotypes, such as uropathogenic, enteroinvasive, enterotoxigenic or enteroaggregative E. coli (Croxen et al, 2013;Ananias & Yano, 2008), highlighting the evolutionary capacity of this particular clone.…”

Life-threatening Escherichia coli cellulitis in patients with haematological malignancies

“…The two isolates were of serogroups O1:K1 (patient 1) and O18:K1 (patient 2). Isolates belonging to these serogroups are frequently identified in urinary tract infections, bacteraemia and neonatal meningitis (Ananias & Yano, 2008;Blanco et al, 1996;Croxen & Finlay, 2010). MLST showed that neither strain had any lineage.…”