Bacteriological Profiles of Pyogenic Wound Infection among Adults with Antibiotic Susceptibility Pattern at a Tertiary Hospital in Nigeria

Aims: A wide variety of aerobic and anaerobic bacteria either singly or in combination has been implicated in pyogenic wound infection and this has been associated with treatment failures due to antibiotic resistance. This study aims at investigating the agents of pyogenic wound infection and their antibiotic susceptibility.

Study Design: A descriptive cross-sectional study conducted at the only tertiary Teaching Hospital in Uyo, Nigeria and carried out on 136 wound samples.

Place and Duration of Study: University of Uyo Teaching Hospital, Uyo, Nigeria, between April and October, 2018.

Methodology: Aspirated pus or wound swab samples were collected and inoculated on two separate agar plates containing 25% Sheep Blood and incubated aerobically and anaerobically at 37°C for 48 – 72 hours. Identification of isolates was performed following standard procedures. Data obtained were analyzed using SPSS software.

Results: Of the 136 collected wound samples from 76 (55.9%) males and 60 (44.1%) females patients from ages 20 to 70 years and above, 127 (93.4%) had growth of different bacterial isolates totaling 214 in number. Among these were aerobes 132 (61.6%) anaerobes 82 (38.4%). The Gram-negative aerobes had the highest prevalence 81 (37.9%), while the Gram-positive anaerobes 20 (9.4%) was the least prevalent. Staphylococcus aureus, 44 (86.3%) and Pseudomonas aeruginosa, 24 (29.6%), were the predominant Gram-positive and Gram-negative aerobes respectively. Peptococci spp. 8 (40%) and Bacteriodes fragilis 28 (54.9%) were the predominant Gram-positive and Gram-negative anaerobes respectively. Some rarely reported pathogens revealed include Acinetobacter iwoffi, Enterobacter cloacae and Stenotrophomonas maltophilia 1(1.2%) and they showed 100% resistance to all tested antibiotics. The majority of the Gram-positive aerobes 29 (56.9%) were Vancomycin resistant and there was also an increasing prevalence of Methicillin resistant Staphylococcus aureus (45%).

Conclusion: The bacterial agents causing pyogenic wound infection in Uyo comprised of 61.6% aerobes and 38.4% anaerobes. Some rarely reported bacteria such as Enterobacter cloacae and A. iwofii implicated in the infections were resistant to all commonly used antibiotics including Imipenem, a reserved antibiotic. Staphylococcus aureus was the commonest cause of pyogenic wound infection and up to 45% of them were Methicillin resistant.