Phenotypic characterization and genomic DNA polymorphisms of Escherichia coli strains isolated as the sole micro-organism from vaginal infections

Abstract

Vaginal infections such as vulvovaginal candiadiasis, trichomoniasis and bacterial vaginosis are common worldwide. Accurate diagnosis and prescription of appropriate treatments are important since these infections are linked to adverse outcomes for women during pregnancy and for newborns. Several aetiological agents are responsible for these infectious diseases; however, the presence of Escherichia coli in these infections is controversial. Thus, it is important to identify some phenotypic and genotypic properties of E. coli strains isolated from vaginal infections. Fortysix E. coli strains isolated from vaginal fluid as the sole micro-organism, and 20 other E. coli strains isolated from other samples (urinary tract infections, otitis and septicaemia) were analysed by several phenotypic tests. In addition, genotypic features were studied by RAPD-PCR techniques. Biochemical tests showed that the E. coli strains isolated from vaginal fluid could be grouped into a single cluster which is subdivided into two phenogroups. Analysis of the dendrogram based on fragment length polymorphisms of genomic DNA indicated that E. coli isolates from vaginal infections form a single cluster with two subdivisions. Further studies are needed to analyse the molecular structure and virulence characteristics of these E. coli strains in order to determine their potential role in vaginal infections.

Aerobic vaginitis in pregnancy

“…Although the role of E. coli in vaginitis is very controversial, this organism remains one of the most frequent causes of neonatal sepsis, and is often recovered from placental tissues in chorioamnionitis. In an interesting study addressing 46 cases in which E. coli was the only microorganism isolated in cultures taken from 425 women with vaginal infection, genetic subtypes of E. coli belonged to the same subgroup in 98% of the cases 22 . The authors suggested that these strains, isolated as the sole microorganism from vaginal infections, constitute a separate subpopulation within the species that is specifically found in vaginal secretions, and differs from E. coli strains cultured from gut, blood or cerebrospinal fluid.…”

Análisis genético y propiedades virulentas de cepas de Escherichia coliaisladas desde infección vaginal

“…Estudios previos basados en la caracterización fenotípica y genómica de los polimorfismos de ADN (RAPD-PCR) revelaron que E. coli aislada desde mujeres con infección vaginal, eran parte de un único grupo genético, lo que implicaría una relación de parentesco entre ellas 14 . Los resultados de esta investigación, realizada con las cepas aisladas desde cultivos monomicrobianos utilizadas en los estudios anteriores 13,14 , permiten evidenciar de modo más certero la relación genética que presentan estas bacterias. Así, se ha logrado determinar la existencia de microorganismos genéticamente idénticos.…”

“…Para ello la muestra vaginal fue recolectada de los fondos de saco lateral y posterior con tres tórulas estériles, las que se utilizaron en la ejecución de los test de Nugent y Amsel, además de una observación directa, para detectar células micóticas. El estudio microbiológico de los otros microrganismos fue realizado de acuerdo a lo descrito en la literatura científica 13,14 . Las cepas de E. coli aisladas desde cultivos monomicrobianos fueron mantenidas en leche descremada (20%) a -70 °C hasta su utilización.…”

“…Escherichia coli es actualmente, junto a Streptococcus agalactiae, un patógeno frecuentemente aislado en sepsis neonatal y meningitis de aparición temprana 11 , siendo responsable, en alguna casuística, de 41% de las sepsis de aparición temprana en recién nacidos prematuros de muy bajo peso al nacer 12 . Por otra parte se ha evidenciado que esta bacteria ha sido aislada, a menudo, desde infección vaginal en cultivos polimicrobianos, asociada a reconocidos agentes de infección vaginal, y también desde cultivos monomicrobianos 13,14 .…”

Virulence genes and antimicrobial susceptibility of Escherichia coli taken from women with vaginitis in Talca, Chile

“…In this context, the isolation of this bacterial species from vaginitis should be studied. Previous studies have indicated that strains of these species might be associated with vaginitis, particularly in women with inflammation, vaginal discharge, and dyspareunia [8,9]. By incorrectly assessing E. coli as a vaginal microbiota member, women infected with these bacterial species are not properly diagnosed or clinically treated.…”