• Braide, W. Department of Microbiology, Federal University of Technology Owerri
  • Ajugwo, G.C Department of Microbiology, Federal University of Technology Owerri
  • Adeleye, S.A. Department of Microbiology, Federal University of Technology Owerri
  • Mike-Anosike E.E. Department of Microbiology, Federal University of Technology Owerri
  • Ndukwe, C.U Department of Microbiology, Federal University of Technology Owerri
  • Chinakwe E.C. Department of Microbiology, Federal University of Technology Owerri



Hospital Indoor Air, Correlation Analysis, Occupant Density, Bacteria, Mold, Spearman Coefficient


A study of the quantity and types of airborne bacteria and its correlation with human presence was conducted. Air samples were collected from different units for three days and three sessions (morning, afternoon and evening) for the enumeration and identification of bacterial isolates. Walk-through exercise was also conducted prior to every sampling to gather information on the number of occupants present, activities going on, and room characteristics. Isolation study revealed higher bacterial load in the afternoon and evening sessions; with Male Ward and Operating Theatre recording the highest and lowest bacterial loads respectively, as compared to the morning session that was done immediately after cleaning and before influx of people. The Spearman’s Correlation Coefficient showed a positively direct linear correlation between the bacterial load and occupant population irrespective of the three sessions (r = 0.84, 0.88 and 0.93). Identification study showed that the isolates are representatives of normal microflora of the skin, respiratory and gastro-intestinal tracts which includes the following; Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus roseus, Klebsiella pneumoniae, Proteus mirabilis, Bacillus subtilis, Aspergillus, Penicillium, Mucor, Candida and Fusarium species. The study presents evidence of increased concentration of indoor airborne bacteria due to human presence, movement and activities.


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Ayliffe, G.A. Role of the Environment of the Operating Suite in Surgical Wound Infection. Rev Infect Dis., 13(10), 1999, 5800-04. DOI:

Beggs, C.B. The Airborne transmission of infection in hospital building: Fact or Fiction? Indoor Built Environment, 12, 2003, 9-18. DOI:

Bhangar, S., Adams, R.I., Pasut, W., Huffman, J.A., Arens, EA and Taylor, J.W. Chamber bioearosol study: human emissions of size-resolved fluorescent biological aerosol particles. Indoor air 10, 2015, 1111. DOI:

Borrielo, P.S., Murray, P.R and Funke, G. Topley and Wilson’s Microbiology And Microbial Infections: Bacteriology-1. Ed 10. Washington DC: American Society for Microbiology Press. 2005, pp 185-94.

Bowers, R.M., McCubbin, I.B., Hallar, A.G and Fierer, N. . Seasonal variabilityin airborne bacterial community at a high-elevation site. Atmos. Environ. 50, 2012, 41-49. DOI:

Cheesbrough, M . Medical Laboratory manual for tropical countries, 2nd Edition. Cambridge, U.K: University Press Cambridge; 2010, pp 508-511.

Edwards, A. L. (1976). The Correlation Coefficient. An Introduction to Linear Regression and Correlation. San Francisco, CA: W. H. Freeman, pp. 33-46.

Ekhaise, F.O., Isitor, E.E Idehen,O and Emogbene, O.A. . Airborne microflora in the atmosphere of a hospital environment of University of Benin Teaching Hospital (UBTH), Benin City, Nigeria. World Journal of Agricultural Science. 6(2), 2010, 166-170.

Feller, W.. An introduction to the probability theory and its application. John Wile and Sons Inc. New York. 1950, p34.

Hinds, W.C.. Aerosol Technology: Properties, Behavior and Measurement of Airborne Particles. 2nd edition, New Jersey:Wiley-Blackwell. 1999

Hospodsky, D., Qian, J., Nazaroff, W.W., Yamamto, N., Bibby, K and Rismaniyazdi, H.. Human occupancy as a source of indoor airborne bacteria. PLOS One 7, 2012:4. DOI:

Jaffal, A.A., Barnat, I.M., Mogheth, A.A and Ameen, A.S. . Residential Indoor Airborne Microbial Populations in the United Arab Emirates. Environmental International, 23(4), 1997, 529-33. DOI:

Kaur, N and Hans, C.. Air bacterial isolates from operating theatre in a tertiary care hospital in India. Journal of Clinical and Diagnostic Research, 2, 2007, 87-89.

Kembel, S.W., Jones, E., Kline, J., Northcutt, D., Stenson, J., Womack A.M and Green J. L.. Architectural design influencesw the diversity and structure of the built environmental Microbiome. ISME J., 6, 2012, 1469-79. DOI:

Lateef, A.. The microbiology of a pharmaceutical effluent and its public health implications. World Journal of Microbiology and Biotechnology, 22, 2003, 167-71. DOI:

Lax, S., Smith, D.P., Hampton-Marcell, J., Owens, S.M., Handley, K.M and Scott, N.M.. Longitudinal analysis of microbial interaction between humans and the indoor environment. Science 345 (6200), 2014, 1048-53. DOI:

Meadow, J.F., Altrichter, A.E., Kembel, S.W., Kline, J., Mhuireach, G and Moriyama, M.. Indoor airborne bacterial communities are influenced by ventilation, occupancy and outdoor air source. Indoor air. 24(1), 2014, 41-8. DOI:

National Committee for Clinical Laboratory Standards, NCCLS. Methods for dilution in antimicrobial susceptibility test. Villanova. Ninth Information Supplied. 25, 1998, 23-29.

Nevalainen, A.. Bacterial Aerosols in Indoor Air. National Public Health Institute, Kuopio. 1989

Okhuoya, J.A and Okaraedge, S.O.. Microflora of roadside air and leaf surfaces of selected vegetables, Nigerian Journal of Pure and Applied Science, 12, 1992, 42-48.

THMP Consortium. Structure, function and diversity of the human microbiome. Nature, 486 (7402), 2012, 207-14. DOI:

Warner, P and Glassco, A. Enumeration of airborne bacteria in hospitals. Canadian Medical Association Journal, 88, 1963, 1280-1283.




How to Cite

Braide, W., Ajugwo, G.C, Adeleye, S.A., Mike-Anosike E.E., Ndukwe, C.U, & Chinakwe E.C. (2019). CORRELATION ANALYSIS BETWEEN INDOOR AIRBORNE BACTERIAL LOAD AND OCCUPANT DENSITY IN HOSPITAL INDOOR AIR. International Journal of Engineering Technologies and Management Research, 6(5), 73–83.