Differences in Virulence Factors and Antimicrobial Susceptibility of Uropathogenic Enterococcus spp. Strains in a Rural Area of Uganda and a Spanish Secondary Hospital

Abstract

Enterococcus faecalis and Enterococcus faecium have become two of the most important agents of nosocomial diseases due to their constantly growing resistance. Enterococcal infections are associated with biofilms, which are intrinsically sensitive to antimicrobials. The main goal of this study was to compare and relate their capacity to form biofilm and their antimicrobial sensitivity, as well as their virulence factors and their implicated genes, of strains isolated from patients with urinary tract infection (UTI) in a rural hospital in Uganda and a secondary hospital in Spain. A prospective study was conducted with 104 strains of E. faecalis and E. faecium isolated from patients with suspected UTI and who presented leukocyturia at the Saint Joseph Kitgum hospital (Uganda) and at the Hospital Universitario Principe de Asturias (Spain). All microorganisms were identified in Spain by MALDI-TOF mass spectrometry. Antimicrobial susceptibility studies were carried out using the Vitek® 2 system (Biomériux, France). The biofilm formation capacity was studied by photospectrometry. Phenotypic and genotypic virulence factors were studied in all cases by PCR or expression techniques. In Uganda, we found a higher incidence of E. faecium (65.3%, n = 32), contrary to the situation found in Spain where most of the bacteria found belonged to E. faecalis (92.7%, n = 51). All E. faecalis strains were found to have very low levels of resistance to ampicillin, imipenem, and nitrofurantoin. However, E. faecium exhibited more than 25% resistance to these antibiotics. Although the esp gene has been shown in the results obtained to be an important initial agent in biofilm formation, we have also demonstrated in this study the intervention of other genes when esp is not present, such as the ace1 gene. No statistically significant relationships were found between the presence of agg and gelE genes and increased biofilm formation. The significant difference between the incidence of E. faecalis and E. faecium and biofilm formation, between samples from Spain and Uganda, shows us very different profiles between countries.

The Science behind Biofilm: Unraveling Enterococcus Genus’ Remarkable Ability to Produce Microbial Communities

“…Collagen type I adherence was found to be highly statistically significantly correlated with a clinical origin serving as the isolate's source [126,127]. The presence of an uninterrupted Acm gene and surface expression of Acm were confirmed in the diverse collection of isolates, indicating the involvement of Acm in collagen adherence [11,128].…”

Cataloging variation in 16S rRNA gene sequences of female urobiome bacteria

“…While the other three sequences in the data set were predicted as Enterococcus by their V4 region, they were assigned to the species E. faecium (Figure 1). Recent studies of urinary strains of E. faecalis and E. faecium have found that the species vary in their resistances to antibiotics (58)(59)(60)(61). Thus, studies that target the V4 region are limited to a genuslevel classification of Enterococcus at best.…”