Virulence Factors of Escherichia coli Isolated From FemaleReproductive Tract Infections and Neonatal Sepsis

Abstract

Objective: The presence of enterobacteria such as Escherichia coli in the vagina of normal women is not synonymous with infection. However, vaginal E. coli may also cause symptomatic infections. We examined bacterial virulenceproperties that may promote symptomatic female reproductive tract infections (RTI) and neonatal sepsis. Methods: E. coli isolated as the causative agent from cases of vaginitis (n = 50), tubo-ovarian abscess (n = 45) and neonatal sepsis (n = 45) was examined for selected phenotypic and genetic virulence properties. Results were compared with the frequency of the same properties among fecal E. coli not associated with disease. Results: A significantly greater proportion of infection E. coli exhibited D-mannose resistant hemagglutination compared with fecal E. coli (p < 0.01). This adherence phenotype was associated with the presence of P fimbriae (pap) genes which were also significantly more prevalent among isolates from all three infection sites (p < 0.01). The majority of pap+ isolates contained the papG3 allele (Class II) regardless of infection type. Increased frequency of Type 1C genes among vaginitis and abscess isolates was also noted. No significant differences in frequency of other bacterial adherence genes, fim, sfa, uca (gaf) or dra were observed. E. coli associated with vaginitis was significantly more likely to be hemolytic ( HIy+) than were fecal isolates (p < 0.05). The HIy+ phenotype was also more prevalent among tubo-ovarian abscess and neonatal sepsis isolates (p < 0.08). Conclusions: E. coli isolated from female RTI and neonatal sepses possess unique properties that may enhance their virulence. These properties are similar to those associated with other E. coli extra-intestinal infections, indicating that strategies such as vaccination or bacterial interference that may be developed against urinary tract infections (UTI) and other E. coli extra-intestinal infections may also prevent selected female RTI.

Prevalence of genes encoding virulence factors among Escherichia coli with K1 antigen and non-K1 E. coli strains

“…The presence of other bacteria such as E. coli may be important, although not necessarily synonymous with infection (Cook et al, 2001). The ability of some E. coli strains to adapt to the vaginal and/or endocervical conditions and to the amniotic fluid, as well as the ability to invade the blood or the cerebrospinal fluid of neonates, correlates with an enrichment of VFs.…”

“…A cluster of sfa and foc genes is necessary for the biogenesis of S and F1C fimbriae (Khan et al, 2000). Johnson et al (2002) reported a frequency of 61 % sfa/foc-positive isolates from infants with NBM, whilst other studies have shown that this percentage is lower (33-44 %; Bingen et al, 1997;Watt et al, 2003), whereas the percentage of E. coli strains with sfa or sfa/foc genes isolated from blood ranges from 9 to 59 % (Bingen et al, 1997;Cook et al, 2001;Watt et al, 2003;Bagger-Skjøt et al, 2007;Soto et al, 2008). In addition, E. coli strains isolated from the vagina frequently possess genes encoding S fimbriae or S and F1C pili (20-48 %; Obata-Yasuoka et al, 2002;Watt et al, 2003;Hilbert et al, 2008).…”

Prevalence Of Bacterial Vaginosis Among Female Students Of Michael Okpara University Of Agriculture,Umudike, Abia State, Nigeria

“…A complex and intricate balance of microorganisms maintains the normal vaginal flora and changes with a multitude of events in the patient"s life (Cook, et al, 2001). The dominant microbial species is Lactobacillus, which maintains the generally acidic vaginal pH (Khan and Khan, 2004).…”

“…The presence in the vagina of other bacteria such as Gardnerella vaginalis, group B streptococci and Esherichia coli termed commensal bacteria (Laren and Monif, 2001) is not synonymous with infection (Cook, et al, 2001). According to Hammill (1989), the incidence of E. coli in the vagina of normal, pre-menopausal, nonpregnant, asymptomatic women is about 21%.…”

Phylogenetic Grouping and Virulence Characterization of ESBL-Producing and Non-Producing Vaginal Escherichia Coli

“…In theory, aerobic vaginitis may be a better candidate than bacterial vaginosis as the cause of pregnancy complications, such as ascending chorioamnionitis, preterm rupture of the membranes and preterm delivery [4]. An extensive analyses of phylogenetic group and virulence factors of E. coli isolated from females reproductive tract infection (RTI) were carried out [7][8][9][10]. In these studies, it was found that vaginal E. coli have unique properties that may enhance their virulence.…”