Schematic Method for Effective Identification of Anaerobes from Infected Surgical Wounds

Abstract

Objective: To investigate post surgical wound infections for anaerobes and to develop effective method for their rapid identification. Method: Fifty seven (57) samples were collected in cooked meat broth, they consisted of 40 wound swabs, 7 pus, 6 vaginal and 4 rectal swabs. They were inoculated into two compounded media; Neomycin Blood Agar (NBA) and Neomycin Plasma Agar (NPA) incubated anaerobically at 37oC for (24-48) hours. Isolated anaerobes were gram-stained and tested using discs impregnated with antibiotics, bile salts and dyes, carbohydrate fermentation and other standard tests were carried out. Results: Abdominal surgery had the highest anaerobes (44%), Musculoskeletal (25%), Splenectomy and related procedures (5%). Severe outcomes associated with anaerobes were amputation of limbs and death. Anaerobes were classified into fragilis group, bile resistant, bile sensitive and Fusobacterium group. Further tests revealed Bacteroides fragilis, Fusobacterium nucleatium, Porphyromonas assacharolytica, Prevotella intermedia, and Peptosterptococcus magnus as most frequently isolated. The developed scheme interlinked the various identification steps: 1st level; inoculation and growth, 2nd level; Gram differentiation and 3rd level; Biochemical characterization. Conclusion: The study has shown anaerobic cultures as essential in the management of patients with post surgical would infections. The scheme serves as a guide of idealized representation to identification of anaerobes.

KEY WORDS: Anaerobes, Culture, Compounded media, Schematic, Surgical wounds