Analysis of Staphylococcus epidermidis Isolates From the Environment and Patient Blood Cultures From an Intensive Care Unit

Background: Staphylococcus epidermidis is most commonly found in blood stream infections, and can present resistance to antimicrobials and the colonization of surfaces.

Objective: The present study aimed to determine the epidemiological characteristics of Staphylococcus epidermidis when present on surfaces, on equipment and in the blood cultures of patients from an Intensive Care Unit (ICU).

Methods: This research consisted of a cross-sectional study carried out between July and October 2009. Samples were collected, by means of cotton swabs, from the cardiac function monitor, mechanical fan, bed grid, bedside table and stethoscope. Samples were cultivated in BHI, MacConkey and Sabouraud Agar solutions at 37º for 48 hours. The bacteria were identified by the morphology of the colony, gram coloration, catalase test and API Kit. The sensibility was verified by the Bauer-Kirby method to detect vancomycin and ciprofloxacin. The isolates from environments and blood cultures were compared by means of the repetitive extragenic palindromic sequences (rep-PCR) and analyzed by the Unweighted Pair-Group method (BioNumerics, 6.0).

Results: This study found ciprofloxacin resistant Staphylococcus epidermidis on the stethoscope, on the bed grid and in patient blood cultures with an important similarity (60-65% - IC: 85%). The greatest similarity (95%) was observed among environmental isolates, in which ciprofloxacin resistant Leuconostoc spp. and Staphylococcus epidermidis could be found.

Conclusions: The similarities among the environmental and patient isolates reinforce the epidemiological importance of the horizontal transference of microorganisms. It could be concluded that the environment near the patients in an ICU can be contaminated by resistant opportunist bacteria, thus suggesting a clonal relation with the clinical isolates.