Investigation of genetic diversity of clinical enterococcus species in uti patients by using random amplified polymorphic DNA (RAPD) analysis in Iraq

The emergence of Enterococcus bacteria as important nosocomial pathogens in recent years has led to the need to investigate the factors involved in the pathogenesis of infections caused by these microorganisms. The aim of this study was to determine the presence, virulence characteristics and genetic diversity of Enterococcus genus bacteria, which are highly prevalent in hospitals in Salahaldeen, Iraq. Therefore, within the framework of this thesis study, the highest rate of E. faecalis species was detected, followed by E. faecium, E. avium and E. gallinarum species. The most frequently isolated clinical sources were urinary tract infections (UTI), gastrointestinal tract (GIT) and blood samples. All isolates identified as E. faecium and E. gallinorum from UTI and hospital colonised isolates were resistant to antibiotics, while E. avium isolates were resistant to vancomycin. The highest resistance rates were found in erythromycin, quinupristin/dalfopristin, tetracycline, norfloxacin, ciprofloxacin, levofloxacin and vancomycin. In addition, 83 (78.3%) of the study samples were classified as multidrug resistant. The most common virulence genetic determinant among E. faecalis samples was gelE, followed by asa1, cylA and esp genes. The frequency of esp gene was higher among E. faecium samples, followed by hyl gene. Three clonal groups were predominant among the study samples, one of which was E. faecalis, defined by the majority of samples resistant to vancomycin and high-level aminoglycosides and carrying the virulence genetic profile formed by the asa1, cylA and gelE genes; the other two included E. faecium samples, which were mostly resistant to vancomycin and carrying virulence genetic markers, especially hyl. In addition, the presence of a single sample of E. avium resistant to vancomycin and carrying the esp virulence gene is noteworthy. In addition, two clones of vancomycin-resistant E. gallinarum were isolated from colonisation of the gastrointestinal tract (GIT) of patients, which is not a common occurrence. Most of the high multidrug resistance rates were isolated from patients hospitalised in intensive care units. This study highlights the growing concern about Enterococcus infections in hospitals, particularly multidrug resistance and vancomycin resistance. Surveillance and infection control measures are essential to prevent the spread of resistant bacteria. Alternative treatment strategies and antibiotics need to be developed to combat these difficult-to-treat infections.