Genotypic and Phenotypic Traits That Distinguish Neonatal Meningitis-Associated Escherichia coli from Fecal E. coli Isolates of Healthy Human Hosts

Abstract

<jats:title>ABSTRACT</jats:title><jats:p>Neonatal meningitis<jats:named-content content-type="genus-species">Escherichia coli</jats:named-content>(NMEC) is one of the top causes of neonatal meningitis worldwide. Here, 85 NMEC and 204 fecal<jats:named-content content-type="genus-species">E. coli</jats:named-content>isolates from healthy humans (HFEC) were compared for possession of traits related to virulence, antimicrobial resistance, and plasmid content. This comparison was done to identify traits that typify NMEC and distinguish it from commensal strains to refine the definition of the NMEC subpathotype, identify traits that might contribute to NMEC pathogenesis, and facilitate choices of NMEC strains for future study. A large number of<jats:named-content content-type="genus-species">E. coli</jats:named-content>strains from both groups were untypeable, with the most common serogroups occurring among NMEC being O18, followed by O83, O7, O12, and O1. NMEC strains were more likely than HFEC strains to be assigned to the B2 phylogenetic group. Few NMEC or HFEC strains were resistant to antimicrobials. Genes that best discriminated between NMEC and HFEC strains and that were present in more than 50% of NMEC isolates were mainly from extraintestinal pathogenic<jats:named-content content-type="genus-species">E. coli</jats:named-content>genomic and plasmid pathogenicity islands. Several of these defining traits had not previously been associated with NMEC pathogenesis, are of unknown function, and are plasmid located. Several genes that had been previously associated with NMEC virulence did not dominate among the NMEC isolates. These data suggest that there is much about NMEC virulence that is unknown and that there are pitfalls to studying single NMEC isolates to represent the entire subpathotype.</jats:p>

Distribution of Strain Type and Antimicrobial Susceptibility of Escherichia coli Isolates Causing Meningitis in a Large Urban Setting in Brazil

“…The results of this study support the findings of previous studies comparing E. coli strains from cases of meningitis and E. coli strains isolated from other sources (14,15,21). These studies showed that the same sequence types are frequently found in E. coli strains that are isolated from meningitis and other sources, and once further typing schemes are applied, differences can be found.…”

“…Isolates of E. coli that have caused neonatal meningitis in developed countries have been extensively studied (10,(14)(15)(16)(17)(18)(19). These studies have found that some serotypes and sequence types predominate among the E. coli strains that cause meningitis.…”

“…The sequence types isolated from cases of meningitis include ST95, ST62, ST131, and ST69 (14,19,20,(22)(23)(24). When combinations of typing methods and more discriminant typing methods are used, isolates that have caused meningitis can be separated from isolates from other sources (15,16). However, most studies examined a limited number of collections of E. coli strains available for study obtained from different geographic sites and time periods, and, hence, it is unclear how significant these differences are.…”

“…These studies have found that some serotypes and sequence types predominate among the E. coli strains that cause meningitis. However, these same serotypes and sequence types are found in E. coli strains isolated from other sources such as urinary tract infections, poultry, and healthy human digestive tracts (15,16,20). Serotypes of E. coli that have been isolated from cases of meningitis include O18:K1, O45:K1, O1:K1, and O83:K1 (14,19,21,22).…”

Zoonotic Potential of Escherichia coli Isolates from Retail Chicken Meat Products and Eggs

“…We classified as NMEC only those isolates that were positive for both K1 and ibeA. However, in previous human isolate surveys, although around 80% of neonatal meningitis isolates were K1 positive (59)(60)(61), only ϳ30% of K1 isolates were also ibeA positive (59,62,63). It is therefore possible that some K1-positive, ibeA-negative isolates, which here were not considered NMEC, could indeed cause neonatal meningitis by utilizing non-ibeA-related mechanisms (64).…”