The Role of Emergency Departments in Cross-Contamination: The Case of VRE

Abstract

Colonized surfaces, equipment, individuals, and infected patients can be sources for the hospital spread of vancomycin-resistant enterococci (VRE), which is one of the important nosocomial pathogens. The basic epidemiological tools for the prevention and control of hospital-acquired infections are the typing methods. Pulsed-field gel electrophoresis (PFGE) is a highly discriminating method used frequently to detect clonal associations in epidemics and hospital-acquired VRE infections. This study aimed to investigate the presence of cross-contamination, which service or services come to the forefront in case of possible cross-contamination and clonal relationship between VRE strains isolated from rectal swab, clinical and environmental swab samples taken in two different periods in various clinics of Istanbul University Istanbul Medical Faculty Hospital by PFGE method. A total of 125 VREs isolated in two different periods were included in the study. Rectal and environmental swab samples were inoculated on Enterococcosel agar and sodium azide broth, urine samples were inoculated on chromogenic agar, and other clinical samples were inoculated on 5% sheep blood agar and incubated for 18-24 hours. VITEK 2 Compact automation system GP panel (bioMerieux, MarcyL'Etoile, France) was used for the species identification of catalase-negative, gram-positive colonies and disc diffusion and minimum inhibitory concentration (MIC) gradient tests were used to determine vancomycin susceptibility. Multiplex polymerase chain reaction was used to search for vanA and vanB resistance genes in isolates identified as VRE, and PFGE was used to determine clonal association. All isolates were identified as Enterococcus faecium with the vanA resistance gene. It was shown that PFGE clones were divided into six types with 65% similarity (A-F), and in this polyclonal spread, the major type was type A, which contained 108 isolates in 37 subtypes existed in the hospital for years. In patients from whom similar isolates were obtained, the high rate of hospitalizations in the same emergency room or in different emergency services in the same building drew attention. Our results showed that the presence of VRE was established in our hospital, new isolates were added from time to time, and there was a cross-contamination. It was observed that emergency services, where infection control measures were neglected due to working conditions, were among the high-risk areas for VRE contamination. In order to better understand the importance of emergency services in cross-contamination, it would be useful to conduct surveillance studies among patients hospitalized in emergency services and monitor the rate of VRE in the services where positive patients were transferred.