Antibiotics Susceptibility Profile of <i>Staphylococcus aureus</i> Clinical Isolates Collected in Hospitals in the City of Douala (Cameroon)

Abstract

Introduction: Staphylococcus aureus is one of the most important agents involved in community and hospital-acquired infections. Due to the multi-drug resistance of strains to antibiotics, treatment to eradicate it is becoming more difficult and poses a global public health problem. Methodology: This was a cross-sectional study conducted from March to August 2020 in hospitals in the city of Douala, including all S. aureus isolates from diagnostic samples. Strain identification and antibiotic susceptibility testing were performed using the Vitek2 CompactTM (BioMerieux). Results: During the study period, 136 non-repetitive S. aureus strains were identified with a high frequency of methicillin-resistant S. aureus of 78.7%. The majority of the strains originated from the Douala General Hospital (66.9%) and was most frequently isolated from blood culture samples (55.1%). The study of biochemical characteristics showed that most of the strains identified had between 87% and 99% homology with the reference strain. The most active antibiotics were Quinupristin/Dalfopristin (94.2%), Linezolid (87.8%) and Vancomycin (84.2%). Methicillin resistance was associated with decreased susceptibility of S. aureus to other antibiotics such as Gentamycin (44.9%), Erythromycin (38.2%), Tetracycline (38.3%), Trimethoprim (21.4%), Ciprofloxacin (19.1%) and Levofloxacin (24.0%). Inducible MLSb and constitutive resistance phenotypes were identified with 26.7% and 22.8% respectively. Conclusion: The sensitivity of S. aureus strains differs from one antibiotic family to another, and remains good for molecules that are not available in our context. The high frequency of Methicillin-Resistant S. aureus shows the continuous progression of multi-resistant strains of S. aureus and their decreased sensitivity to usual antibiotics becomes more and more alarming.