Prevalence of Antimicrobial Resistance Among Gram-Positive Isolates in An Adult Intensive Care Unit at A Tertiary Care Center in Saudi Arabia

Abstract

Objectives: To estimate the prevalence of Gram-positive infections in intensive care units (ICU), and to observe the patterns of resistance against different antibiotics. Methods: A retrospective cross-sectional study was conducted of all reports of Gram- positive isolates from adult ICU of King AbdulAziz Medical City, Riyadh between 2010 and 2014. Organisms were identified and tested by an automated system and the antibiotic susceptibility was confirmed by manual method. Results: Among 2155 Gram-positive isolates, methicillin-susceptible Staphylococcus aureus (MSSA) were the most commonly isolated organism followed by Enterococcus, Methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pneumonia and Coagulase-negative Staphylococci. MRSA resistance decreased to clindamycin, erythromycin, and trimethoprim/sulfamethoxazole. Coagulase-negative Staphylococci showed a significant increase in the resistance to cefazolin, and erythromycin. There was an increase in resistance to ampicillin, and vancomycin among Enterococcus, however there was a decrease in the resistance to ciprofloxacin, and nitrofurantoin. Streptococcus pneumoniae showed a significant decrease in resistance to cefotaxime (50% to 0%). Vancomycin showed 100% sensitivity to MSSA, MRSA, Coagulase negative Staphylococcus, and Streptococcus pneumoniae. Conclusion: Our study revealed that antibiotic resistance among Gram-positive organisms remains a continuous issue in the healthcare setting. To reduce further progression in the 3 emergence of MDR organisms, a continuous surveillance program for bacterial resistance is advised.