Susceptibility Profile of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates to Antibiotics and Methanolic Extracts of Parkia biglobosa (Jacq) Benth

Aims: To study the susceptibility profile of methicillin-resistant Staphylococcus aureus (MRSA) isolates from orthopaedic patients to antibiotics and methanolic extracts of Parkia biglobosa.
Background: Antimicrobial resistance in Staphylococcus aureus has attained alarming proportions worldwide; with methicillin resistant Staphylococcus aureus (MRSA) becoming a major pathogen of public health importance associated with community and hospital acquired infections. Wound infections in orthopaedic patients with multidrug resistant pathogens significantly delay or prevent the union of fractured bones. The increasing prevalence of multidrug resistance in Staphylococcus aureus isolates calls for the search for alternative anti-staphylococcal agents.
Methodology: Suspected staphylococcal isolates from wound, skin and bed swab samples from orthopaedic patients in a tertiary hospital in Zaria, Nigeria were characterized by established microbiological procedures and their antibiotic susceptibility pattern determined by the Kirby-Bauer-CLSI modified disc agar diffusion (DAD) technique. The activity of crude methanolic extract of the root, stem bark and leaf of Parkia biglobosa on the isolates determined.
Results: A total of 179 isolates were confirmed S. aureus: wounds (24.6%), skin (39.1%) and bed (36.3%). The isolation rates for MRSA from the various sites were: wound (75%), skin (51.4%) and bed (73.8%). Antibiotic susceptibility testing revealed that the isolates were generally resistant to ampicillin (100% for all sites); ceftriazone (wound 69.7%, skin 72.2%, bed 70.8%); gentamicin (wound 54.5%, skin 52.8%, bed 37.5%) and ciprofloxacin (wound 51.5%, skin 47.2%, bed 35.4%). The phytochemical screening of the methanolic extract of the leaf, root and stem bark of Parkia biglobosa showed the presence of saponin, tannin, flavonoids and cardiac glycosides. The stem bark of Parkia biglobosa showed the greatest activity against all the multidrug resistant MRSA isolates at the 10mg/ml-25mg/ml concentration range used. In the search for alternative antistaphylococcal agents from natural sources, Parkia biglobosa will be a possible candidate for further investigation.
Conclusion: There was high prevalence of multidrug resistant Staphylococcus aureus isolates from the clinical and surveillance samples from the orthopaedic patients.