Distribution of oral mucosal bacteria with mecA in patients undergoing hematopoietic cell transplantation

Purpose: We recently reported frequent detection of antibiotic-resistant bacteria on the oral mucosa during the period of hematopoietic cell transplantation (HCT) and suggested an association between oral mucositis and antibiotic-resistant bacterial infection. Methicillin-resistant Staphylococcus spp. were frequently detected, and the oral cavity may be a reservoir of the gene mediating methicillin resistance, mecA. Here, we examined the frequency of mecA carriers in patients undergoing HCT. Methods: Fifty-nine patients (male (M)=37, female (F)=22, 47.3±11.0 years) receiving HCT were enrolled in this study. Buccal swab samples were obtained four times from day -7 to day +20 (once/week), and mecA was detected by PCR. Fifty-two subjects without systemic disease, who completed dental treatment, especially periodontal treatment (M=21, F=31, 55.4±14.2 years), were also enrolled as controls and checked for mecA on the oral mucosa. Results: Seventy-six percent (45/59) of the HCT patients carried mecA at least once in the study period (days -7 to +20), while no control subjects had mecA. The frequency of mecA carriers was 19.2 % from days -7 to -1, while it was significantly increased on days +7 to +13 and +14 to +20, with frequencies of 60.9 and 63.2 %, respectively (P<0.01, ANOVA). Conclusions: mecA was detected in oral mucosa of patients undergoing HCT. The high detection frequency of staphylococci resistant to penicillin and beta-lactams in our recent report was supported.