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Updated: Nov 17, 2025
Composition and Distribution Analysis of Bioaerosols Under Different Environmental Conditions
Published on: January 7, 2019
Kytococcus sedentarius and Micrococcus luteus: highly prevalent in indoor air and potentially deadly to the
A Folayan1, K Mohandas2, S Ambu1
1The International Medical University, No.126, Jalan 19/155B, Bukit Jalil, 57000 Kuala Lumpur, Malaysia.
Abstract:
The multifarious types of infections contracted from indoor environments show that buildings can serve as a reservoir for infectious bacteria. This study is an investigation into the type and concentrations of bacteria in the indoor and outdoor environments of an electronic factory, an office and a winery in Malaysia. Trypticase soy agar (TSA) (with ambient air incubation) and TSA supplemented with haemin and NADH (with CO2 enhanced incubation) were used for the isolation of bacteria. The plates were incubated at 37ºC for 3 days. A random selection of bacterial isolates were Gram stained and identified using the BD BBL Crystal Identification Systems. Kytococcus sedentarius and Micrococcus luteus were the predominant bacterial species identified from indoor air. These bacteria were present at relatively high concentrations in indoor air, at times, above 800 colony forming units per cubic meter (CFU/m3) of air. This indicates that both K. sedentarius and M. luteus can survive a wide range of adverse conditions, including chemical contamination and ultraviolet exposure. M. luteus is a known cause of pneumonia in immunocompromised individuals and has also been implicated in skin infections. Recent reports suggest species of kytococci as emerging opportunistic pathogens of the immunocompromised, paediatrics and the elderly. We postulate that opportunistic bacteria, such as the kytococci and the micrococci, may also have a potential role in instigating subclinical, more subtle symptoms of disease in inmmunocompetent individuals.
Insights
Indoor air in Malaysian buildings harbors significant levels of Kytococcus sedentarius and Micrococcus luteus. These bacteria, found at high concentrations, may pose health risks, especially to vulnerable populations.
Area of Science:
- Microbiology
- Environmental Science
- Public Health
Background:
- Buildings can act as reservoirs for infectious bacteria.
- Indoor environments harbor diverse microbial communities.
- Understanding indoor bacterial populations is crucial for public health.
Purpose of the Study:
- To identify and quantify bacteria in indoor and outdoor air of Malaysian electronic factories, offices, and wineries.
- To assess the prevalence of specific bacterial species in different indoor environments.
- To evaluate the potential health implications of identified bacteria.
Main Methods:
- Bacterial isolation using Trypticase soy agar (TSA) with ambient air and CO2-enhanced incubation.
- Incubation of bacterial cultures at 37°C for 3 days.
- Identification of bacterial isolates via Gram staining and the BD BBL Crystal Identification Systems.
Main Results:
- Kytococcus sedentarius and Micrococcus luteus were the predominant species found in indoor air.
- High concentrations of these bacteria, exceeding 800 CFU/m³, were detected indoors.
- K. sedentarius and M. luteus demonstrated resilience to adverse conditions like chemical exposure and UV radiation.
Conclusions:
- K. sedentarius and M. luteus are significant components of indoor air bacteria in the studied Malaysian environments.
- These opportunistic pathogens pose potential risks, particularly to immunocompromised individuals, the elderly, and children.
- Further research is needed to explore the role of these bacteria in subclinical disease manifestation in immunocompetent individuals.
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