High prevalence of Staphylococcus haemolyticus and Staphylococcus saprophyticus in environmental samples of a Tunisian hospital

The purpose of this study was to evaluate the rate of detection of coagulase negative staphylococci (CoNS) in environmental samples of 17 services in a Tunisian hospital, determining the antimicrobial resistance phenotypes and genotypes of recovered isolates. To our knowledge, this is the first study that determines the prevalence of CoNS with correlation of antibiotic resistance in the hospital environment in Tunisia. CoNS were obtained from 83 of the 200 tested samples (41.5%). Staphylococcus haemolyticus was the most prevalent species (45.8%), followed by S. saprophyticus (36.1%). The remaining CoNS species detected were S. epidermidis, S. cohnii, S. warneri, S. sciuri, S. simulans, S. pasteuri, S. arlettae, and S. xilosus. Methicillin-resistant CoNS were detected in 20 of the 200 tested samples (10%), and the mecA gene was demonstrated in 18 S. haemolyticus, one S. epidermidis and one S. saprophyticus isolates. Methicillin susceptible isolates were detected in 63 samples (31.5%). Antimicrobial resistance genes detected were as follows (number of isolates): erythromycin [msr(A) (n = 32); erm(C) (n = 8)], tetracycline [tet(K) and/or tet(M) (n = 21)], gentamicin [aac(6′)-Ie-aph(2″)-Ia (n = 16)], kanamycin [(aph(3′)-IIIa (n = 19)], tobramycin [ant(4′)-Ia (n = 14)], and streptomycin [ant(6′)-Ia (n = 3)]. The high frequency of detection of multi-drug-resistant CoNS in the hospital environment, especially S. haemolyticus and S. saprophyticus, is of relevance and could be due to cross-transmission between patients, staff, and environment.