Multidrug resistance among methicillin-resistant Staphylococcus aureus in long-term care facilities in Greece

Abstract number: 1134_02_195

Grammelis V., Tsekes G., Chalkiadaki D., Salpigktis G., Orlandou K., Kanellakopoulou K., Giamarellou H., Lazanas M.C.

Objective:

A multicentre point-prevalence survey was conducted in order to determine the prevalence and risk factors for colonization with multidrug-resistant (MDR) MRSA in residents of LTCF in Greece estimate the corresponding rates of antimicrobial resistance (ÁR)

Methods:

A total of 28 LTCF were randomly selected from the public sanitation list of Attica province. Nasopharyngeal and wound samples were collected from 862 elderly residents. We chose randomly 30% of the existing population from each LTCF (minimum sum 35 residents). Cultures and susceptibilities were performed, following NCCLS guidelines. The minimal inhibitory concentrations (MICs) of methicillin-susceptible S. aureus (MSSA) and MRSA to 15 alternative antibiotics were also compared. Results were analysed using either the Fischer's exact or chi-square test. Risk ratios and p values were calculated.

Results:

905 samples were collected and 286 strains of S. aureus were isolated. From them, 214 (74.8%) were MSSA and 72 (25.2%) MRSA. In contrast to MSSA, most of MRSA isolates (90% versus 22%) were MDR. Among MDR-MRSA, 49.6% were resistant to chloramphenicol, 39.4% to erythromycin and 34.2% to clindamycin. Also, the ÁR to gentamicin and ciprofloxacin were 29.5% and 19.2% respectively. The most effective agents were linezolid and vancomycin, to which no resistant strains were found, followed by quinupristin/dalfopristin, fucidic acid, trimethoprim-sulfamethoxazole and rifampicin with ÁR lower than 10%. Overall, MRSA vs. MSSA exhibited a significantly higher incidence of resistance to 10 out of the 15 antibiotics examined. In multivariate analysis, colonization with MDR-MRSA was significantly associated with recent hospitalization (p = 0.001), poor functional status (p = 0.001), decubitus ulcers (p = 0.01) and feeding tube (p = 0.01).

Conclusions:

1. Colonization with MDR-MRSA is worrisome in Greek LTCF 2. Macrolides and lincosamydes should be used with caution in case of infections caused by S. aureus, due to increasing antibiotic resistance. 3. According to our survey, significant risk factors for colonization with MDR-MRSA in Greek LTCF are recent hospitalization, poor functional status, decubitus ulcers and usage of feeding tube.