2018 Volume 71 Issue 3 Pages 113-121
Background. Patients staying in intensive care units (ICU) usually have a variety of comorbidities including hospital-acquired infections (HAI), and can often be received antimicrobials as treatment or prophylaxis for HAI. Administration of any antimicrobials ought to affect normal bacterial flora of the patients, which could be a risk for antimicrobial resistance (AMR). Active surveillance culture in ICU is known to be one of the useful measures against AMR. The aim of this study is to evaluate the effects of antimicrobials on bacterial flora of nasal mucosa of the patients in ICU.
Methods. Patients were eligible for this study if they stayed in the ICU at Yamagata Prefectural Central Hospital from June 2015 through September 2016. Active surveillance was done by nasal swab culture from all the eligible patients once a week until they left from ICU. Bacterial or fungal cultures were isolated from the culture samples and detected by using VITEK2 microbial identification system (SYSMEX bioMérieux). Clinical parameters were retrospectively assessed in the study group. Data were statistically analyzed using JMP 11 software.
Results. A total of 614 nasal swab samples from 364 patients were subjected to microbial cultures. Among 614 samples, 550 bacterial or fungal cultures were isolated and 64 were negative culture. Four hundred fifty-nine samples were obtained as initial ASC (length of ICU stay <1 week), and 155 were follow-up ASC (length of ICU stay ≥1 week). The isolation of Streptococcus species was significantly lower in follow-up ASC than initial ASC; whereas those of Enterobacteriaceae, Glucose non-fermenting gram negative rods, Candida species were significantly higher in follow-up ASC than initial ASC (p<0.05, Chi-square test). Furthermore, normal nasal bacterial flora was significantly decreased in patients with the following parameters: longer ICU stay and antibiotic use (p<0.05, Chi-square test). Multivariate analysis indicated that longer ICU stay and antibiotic use were the independent risk factors that could alter the nasal bacterial flora of ICU patients (Odds Ratio 1.06, per 1-week increase [95% confidence interval: 1.009–1.14] and 2.1 [1.2–3.7], respectively).
Conclusion. Administration of antibiotics cloud affect nasal bacterial flora in ICU patients. ASC would be a useful tool for infection control and antimicrobial stewardship in ICU.
