EVALUATION OF INDOOR AIR BACTERIA LOAD AND THE ANTIBIOTIC SUSCEPTIBILITY PROFILE OF ISOLATES FROM LIBRARIES IN KADUNA STATE UNIVERSITY, NIGERIA

Abstract

Background: The quality of air inhaled by man has the tendency to impact his state of well-being. 
Since considerable number of hours are usually spent in the library by students and lecturers the 
microbiological quality of university libraries’ indoor air is highly essential. The aim of this study 
was to assess the microbiological quality of indoor air of the libraries in Kaduna State University, 
and to determine the antibiotics susceptibility of the bacteria isolated. 
Methods: A total number of 26 samples were collected from eight Libraries including the 
University main Library and Faculty Libraries morning and afternoon. Settle plate method, using 
open petri dishes containing nutrient agar was used, bacterial concentration of the indoor air in the 
various sampling site was determined. Biochemical tests were used to identify the bacterial 
isolates. Agar disc diffusion method was used for the susceptibility testing and multidrug resistant 
bacteria was detected. 
Results: The concentration of bacteria in the university indoor air ranged from 1.26 x 103 to 6.13 
x 103 CFU/m3. The bacteria isolated were Staphylococcus aureus 7 (28%), Bacillus subtilis 7 
(28%), Klebsiella pneumoniae 4 (16%), Streptococcus pneumoniae 3 (12%), Micrococcus spp 2 
(8%) and Pseudomonas aeruginosa 2 (8%). Amoxicillin- clavulanate (84.2%) was the most active 
against Gram positive organisms while gentamicin (83.3%) was the most active against Gram 
negative. Five (83.3%) and 9 (47.4%) of Gram negative and Gram positive respectively were 
multidrug resistant.  
Conclusion: The indoor air of Kaduna State University libraries was highly contaminated with 
bacteria. Proper and regular cleaning of the libraries at least twice a day, and proper ventilation are 
recommended.