Colonisation by resistant Staphylococcus epidermidis strains in patients qualified for routine vascular reconstructions

Abstract number: 1733_1204

Mazur E., Niedzwiadek J., Niwinska A., Terlecki P., Wronski J., Koziol-Montewka M.

Objectives: The aim of our study was to examine S. epidermidis colonisation of the anterior nares in patients qualified for routine vascular reconstructions on the day of admission to the hospital and after a week of staying there and to evaluate antimicrobial susceptibility of isolated strains, including detection of resistance mechanisms.

Methods: The study included 35 patients with PAOD (peripheral occlusive arterial disease) qualified for routine vascular reconstruction. Nasal swabs were obtained on the day of admission and on 8th day of hospital stay. Classification to the species was done on the ground of the biochemical properties of isolated strains. Susceptibility to antibiotics was assessed by disc-diffusion method.

Results:S. epidermidis was present in all but one admission culture, in 8th day cultures this species was isolated from 33 patients. In every performed culture 1 to 3 different strains of S. epidermidis were isolated. In 6 patients no changes in S. epidermidis strains were noticed comparing first and second culture, in 7 ones a total change of isolated strains occurred during hospital stay. As a total 73 strains of S. epidermidis were isolated, 26 strains were present in both cultures, 23 strains were acquired in the hospital, 24 strains were lost during hospitalisation. 17 resistant strains were brought into the hospital, among them 10 MR (methicillin-resistant), 10 MDR (multidrug-resistant) and 6 MLSB (some resistance mechanisms were present in the same strain simultaneously). During hospital stay the examined patients were colonised with 12 resistant strains of S. epidermidis, among them 11 MR, 8 MDR, 4 MLSB. 28.8% of strains were resistant to methicillin (MRSE), all of them were fully susceptible to vancomycin, teicoplanin, and mupirocin. 13.7% of isolated S. epidermidis strains possessed MLSB resistance mechanism. 24.7% of S. epidermidis strains were multiresistant, 72.2% of them were simultaneously methicillin-resistant.

Conclusions: Due to high rate of resistant strains among S. epidermidis isolated from patients prepared for routine vascular reconstructions it seems useful to evaluate nasal colonisation in every subject before and after such intervention to:

1. have the opportunity to verify perioperative antibiotic prophylaxis in selected cases and to prevent possible complications;

2. limit the expansion of resistant strains of S. epidermidis in the hospital.