Authors : Ako-Nai Ajibade Kwashie, Adeyemi Folasade Muibat, Adesiyan Ibukun Modupe, Bisi-Johnson Mary Adejumoke and Awojobi Olusayo Kehinde
Abstract: The study was undertaken to isolate and identify bacterial species colonising six different body sites of apparently healthy students. Three hundred and one students participated in the study. The mean age of male participants was 22.1 years and that of the females’ was 22.2 years. About 886 samples were taken from the participants. Altogether, 1394 bacterial isolates were cultured from the samples averaging 1.57 bacteria per sample. Samples from the foot, hand and face were collected into sterile saline and a loop-ful of each sample was applied on blood agar, selective and differential media and other conventional media and incubated at 37°C for 24-48 h. Samples from the ear, nose and throat were collected with sterile cotton-tipped applicators after which each applicator had been dipped into sterile saline and processed. Characterisation of bacterial isolates was initially based on gram-reaction. Cocci that appeared in clusters and fermented mannitol on mannitol salt agar, coagulated human pooled plasma were confirmed as Staphylococcus aureus isolates. Those that neither fermented mannitol on (MSA) nor coagulated human pooled plasma were deemed Staphylococcus sp. Cocci in small chains on blood agar were deemed Streptococci and their pattern of hemolysis or lack of it on blood agar plates was used to classify them. Gram negative rods were categorised as lactose fermenters or non-lactose fermenters based on their reaction on Triple Sugar Iron agar (TSI). Others gram-negative enteric rods were characterised based on their reactions on Eosin Methylene Blue agar (EMB) and other conventional media. Antibiotic susceptibility tests were done on some isolates using the disc dilution method. Out of the 1394 bacterial isolates cultured, gram-positive isolates constituted 57.8% and gram-negative enteric rods 42.2%. Staphylococci accounted for 32% of gram-positive bacterial isolates with Staphylococcus aureus being 72.8% and Staphylococcus sp. was 27.1%. Staphylococcus aureus (23.3%) was the single most predominant gram- positive bacterial isolate cultured followed by E. coli (14.0%) which was the single most predominant gram-negative bacteria seen. Other gram-positive isolates seen include Streptococcus sp. (11.3%), Bacillus sp. (9.9%) and Corynebacterium sp. (2.4%). Gram negative rods seen were: Klebsiella sp. (10.6%), Pseudomonas sp. (5.5%) Proteus sp. (5.0%), Pseudomonas aeruginosa (3.4%), Salmonella sp. (1.9%) Citrobacter sp. (1.1%) and Shigella sp. (0.6%). The antibiotic resistant profile showed 69.9% S. aureus isolates were resistant to amoxicillin 60.3% to augmentin and 60.8% to cloxacillin however, some S. aureus isolates were more amenable to ofloxacin (12%) while other S. aureus isolates demonstrated multi-resistance.
Ako-Nai Ajibade Kwashie, Adeyemi Folasade Muibat, Adesiyan Ibukun Modupe, Bisi-Johnson Mary Adejumoke and Awojobi Olusayo Kehinde, 2012. A Survey of Bacterial Isolates Cultured from Apparently Healthy Individuals in South-Western Nigeria. International Journal of Tropical Medicine, 7: 130-137.