RESUMO
Objectives: Multi-drug resistant bacteria have been implicated in various debilitating infections that have led to life loss. This study developed an approach to tackle multidrug resistant Acinetobacter baumannii infection in a chronic wound model through A. baumannii phage encapsulation with resuspension in hydrogel. Materials and Methods: Two isolates of A. baumannii-specific lytic phases ɸAB140 and ɸAB150 alone, in combination (cocktail) encapsulated within a chitosan (CS) microparticle was suspended in CS hydrogel and evaluated for their therapeutic efficacy to ensure bacterial clearance in A. baumannii induced diabetic wound infection. Microencapsulation of the phage was carried out using ionic gelation techniques Biological characterization via cell cytoxicity, in vivo wound healing, histology and histomorphometry was carried out. Results: Two characterized A. baumannii phages (ɸAB140 and ɸAB150), specific to twenty A. baumannii isolates, were isolated. The encapsulated CS microparticle hydrogel exhibited a pH of 5.77 ± 0.05. The wound size reduction was most pronounced in formulation C2, which showed statistically significant wound seize reduction on days 4 and 7, 56.79 ± 2.02% and 62.15 ± 5.11%, respectively. The optimized concentration of C2 was not toxic to the cells as it adequately supported cell growth with a proliferation rate of 215 ± 7.89% compared to control (107.32 ± 4.55%). Conclusion: Microparticle carrier technology was used to show the lytic activity against multi drug-resistant A. baumannii. In vivo results showed significant wound size reduction that was most pronounced in formulation C2 on day 4.
RESUMO
BACKGROUND: Resistant and virulent Staphylococcus aureus is a global public health challenge. Staphylococcal Bi-component leukotoxins are cytolytic to immune cells and evolve to disarm the innate immunity during infections, hence the severity of the disease. OBJECTIVE: We studied drug resistance profile and the occurrence of bi-component leukocidin in clinical and nasal S. aureus in Lagos, Nigeria. METHOD: Ninety-two S. aureus (70 clinical and 22 nasal) strains were characterized by conventional and molecular methods. RESULT: Of the resistance profiles generated, no isolate was resistant to fosfomycin, fusidic acid, teicoplanin, vancomycin, linezolid, mupirocin, nitrofurantoin and tigecycline. Twelve MRSA carrying staphylococcal cassette chromosome mecA gene types I, III, and IV elements were identified only in the clinical samples and type I dominated. High rates of lukE/D (100% among MRSA) and lukPV (dominated MSSA) were recorded among the nasal and clinical isolates. Staphylococcus aureus harboring only lukE/D (from clinical & colonizing MSSA) and combined lukE/D and lukPV (mostly from clinical MSSA, colonizing MSSA and clinical MRSA) toxins were found. CONCLUSION: Although, mecA resistant genes were found only among clinical MRSA, the occurrence of other bi-component leukocidin genes in a large proportion among the isolates from both community and clinical settings is a major concern. The need for effective resistance and virulence factor surveillance, re-enforcement of antibiotic stewardship and good infection control policy, to prevent dissemination of epidemic strains is highlighted.