Comparison of the rate of enteric colonization with vancomycin-resistant enterococci in medical wards with surgical wards of Namazi Hospital in Shiraz.

Enterococci were the first organisms which developed resistance to vancomycin. In the recent years, they have shown resistance to many antibiotics and vancomycin is one of such antibiotics. Risk factors for rectal colonization with vancomycin-resistant enterococci include patient related factors such as underlying diseases and hospital related factors such as duration of hospitalization, treatment procedures and antibiotic use. In this study the prevalence and risk factors for rectal colonization with vancomycin-resistant enterococci (VRE) in the medical and surgical wards were assessed and the results of the study in the 2 above mentioned wards were compared with each other. Serial rectal swabs were obtained from 370 hospitalized patients in seven medical wards and 143 patients in five surgical wards every five days. Sampling method was stratified random sampling. During the study 750 samples of rectal swab were taken under sterile conditions. Enterococci were detected by disk diffusion method and their resistance to vancomycin was verified by minimum inhibitory concentration dilution method. Chi square and T tests were used for data analysis. Among 513 patients, 76 (15%) were colonized with VRE (cases) and 40 patients with vancomycin-sensitive strains (VSE). Medical wards showed a higher rate of colonization (18.1%) in comparison to surgical wards (6.3%). In surgical wards, prevalence of VRE was related to clinical outcome (p=0.04) and major surgery (p=0.000), but in medical wards, VRE colonization showed a significant relationship with duration of hospitalization (p=0.03), underlying disease (p=0.04), the number of antibiotics (p=0.02), renal failure, history of dialysis (p=0.01) and duration of antibiotic use. Our study demonstrates that VRE prevalence in medical wards is three times as those of surgical wards. Considering longer period of hospitalization, use of more drugs for longer periods and also presence of underlying diseases in medical ward patients, performance of infection control strategy in regard to VRE seems necessary.