National surveillance of antimicrobial resistance among Gram-positive bacteria in Saudi Arabia.

Background: Antimicrobial-resistant Gram-positive bacteria are important causes of serious infections.

Methods: Between January and December 2009, we examined clinical Gram-positive isolates from 24 hospitals across Saudi Arabia.

Results: Among the 13750 isolates, Staphylococcus aureus (62.3%) was the commonest, followed by non-group A beta-haemolytic streptococci (14.8%), group A beta-haemolytic streptococci (7.1%), coagulase-negative staphylococci (6.6%), pneumococci (6.0%), and enterococci (3.1%). Resistance rates were high among S. aureus (methicillin-resistant S. aureus: 32%), coagulase-negative staphylococci (oxacillin: 63%) and pneumococci (penicillin G: 33%; erythromycin: 26%; ceftriaxone: 11%); low among enterococci (vancomycin: 1%) and among beta-haemolytic streptococci. Resistance rates varied between regions, but comparison was complicated by differences in antibiotics tested. Many relevant antibiotics were tested against few isolates (e.g. ampicillin, vancomycin, and high-level gentamicin versus enterococci) while unhelpful tests were widely performed (e.g. cefotaxime, ceftriaxone, and imipenem versus staphylococci.

Conclusion: Resistance is widespread in staphylococci and pneumococci, but not enterococci and beta-haemolytic streptococci in Saudi Arabia. Rationalization of antibiotic panels tested is urgently needed.