MICROBIOLOGICAL ASSESSMENT OF INDOOR AND OUTDOOR AIR OF MICROBIOLOGY LABORATORY OF MOUAU

ABSTARCT

This study was designed to assess the microbiological quality of indoor and outdoor air of Microbiology laboratory of Michael Okpara University of Agriculture, Umudike. A total of six (6) air samples from the laboratory were collected and cultured on Nutrient Agar, MacConkey Agar, Nutrient Agar, Sabouraud Dextrose Agar and Salmonella-Shigella Agar using sedimentation techniques. From this study, a total of thirty (30) microbial species were isolated and identified as Bacillus sublitis, Staphylococcus aurues, Escherichia coli, Klebsilla spp, Streptococcus species, Aspergillus niger, Mucor alternaria and Aspergilus fumigates. This study showed that, Microbiology laboratory Umudike, Umuahia, Outdoor (afternoon) had the highest viable mean bacteria count (11.1x104), followed by Outdoor (morning) 10.5x104, Indoor (evening) 7.7x104, Outdoor (evening) 5.3x104, Indoor (afternoon) 5.2x104, while the least viable mean bacteria count was recorded on Indoor (morning) 3.8x104. The total viable mean fungal plate count showed that Outdoor air sample (afternoon) had the highest viable mean fungi count (13.2 x104), while Indoor (afternoon) air sample had the least viable fungi count (2.3 x104). The contamination rate and percentage distribution accessed on the Indoor laboratory Air samples in Microbiology laboratory revealed that, among the indoor air isolates Escherichia coli and Staphylococcus aureus are the most frequently occurring isolates, with a high percentage occurrence of 3(23.1%) each, while among the outdoor air isolates, Escherichia coli, Staphylococcus aureus and Bacillus spp and are the most frequently occurring isolates with a high percentage occurrence of 3(17.6%) each. However, there were slight variations in the fungi population, with Mucor alternaria 2(15.3%) being most predominant and occurring isolates, while from the outdoor laboratory air sample, Aspergillus fumagatus was the most predominant and occurring isolate at 2(11.8%). Therefore, the present work shows that the outdoor laboratory air is heavily contaminated with bacteria and fungi loads than the indoor air sample.

TABLE OF CONTENTS

Title Page   i

Certification iii

Dedication iv

Acknowledgements v

Table of Contents vi

List of Tables vii

Abstract ix

CHAPTER ONE

1.0 Introduction 1

1.2 Aim and Objectives 3

CHAPTER TWO

2.0 Literature Review 5

2.1 Assessment of Airborne Bacteria and Fungi in an Indoor and Outdoor 

Environment 5

2.2 Microbiological Indoor and Outdoor Air Quality of Selected Places in

India 7

2.3 Microbiological Indoor and Outdoor Air Quality of Two Major 

Hospitals in Benin City, Nigeria 9

2.4 Microorganisms Associated with Airborne Contaminations 10

2.4.1 Bacteria Example 11

2.4.2 Fungi Example 11

2.4.3 Virus Example 11

2.5 Factors that Affect Indoor and Outdoor Air Quality 11

2.5.1 Temperature 12

2.5.2 Relative Humidity 12

2.5.3 Microbes 13

2.5.4 Chemicals 13

2.5.5 Radiation 13

2.5.6 Oxygen, OAFs, and Ions 14

CHAPTER THREE

3.0 Materials and Methods 16

3.1 Study Area 16

3.2 Materials 16

3.3 Media Preparation 16

3.4 Sterilization of Materials 16

3.5 Sampling Techniques 16

3.6 Identification of the Isolates 17

3.7 Gram Staining 17

3.8 Biochemical Tests 18

3.8.1 Catalase Test 18

3.8.2 Indole Test 18

3.8.3 Citrate Utilization Test 18

3.8.4 Hydrogen Sulphide (H2S) Production Test 19

3.8.5 Starch Hydrolysis 19

3.8.6 Motility, Indole, Urease (MIU) 19

3.8.7 Coagulase Test 20

3.8.8 Oxidase Test 20

3.9 Identification of Fungal Isolates 20

3.9.1 Wet Preparation 20

3.9.2 Colonial Morphology 21

CHAPTER FOUR

4.0 Results 22

CHAPTER FIVE

5.0 Discussion, Conclusion and Recommendations 30

5.1 Discussion 30

5.2 Conclusion 35

5.3 Recommendations 36

References 

LIST OF TABLES

CHAPTER ONE

1.0  INTRODUCTION

The air inhaled by people is contaminated by microorganisms which form so-called bioaerosols (Wojtatowicz et al., 2008). Bioaerosol is a colloidal suspension, formed by liquid droplets and particles of solid matter in the air, whose components contain or have attached to them viruses, fungal spores and conidia, bacterial endospores, plant pod fragments of plant tissues (Karbowska-Berent et al., 2011).They account for 5-34% of indoor air pollution. Indoor air plays a special role as a health determinant and management of indoor air quality re approaches that differ from those used for outdoor air. For these reasons, the working group preparing the global update of the WHO air quality guidelines (WHO, 2008) recommended that WHO also prepare guidelines for indoor air quality. Microbial damage in indoor and outdoor areas is caused most frequently by molds and bacteria. This constitutes a common problem all over the world. The most significant environmental factors influencing the viability of microorganisms are temperature, relative humidity wind velocity (Jones, 2003). Also, the additional influences are exerted through oxygen, air ions, solar irradiance, and open monitoring of outdoor airborne microorganisms is necessary to evaluate the risk on human health and to study its evolution, and the interest in bioaerosol characterization has increased over the last few decades (Hurst, 2001).

The air quality in indoor and outdoor environments has attracted research interest during the past decades or so (Jones, 2003). Most problems related to indoor and outdoor air quality result from complex interactions among building occupants, indoor environment (inadequate temperature, excessive humidity), insufficient outdoor air intake, building materials and furnishing, and air contaminants (chemicals, bacteria, molds, vapors) (Yu et al., 2009). Airborne bacteria are ubiquitous in the earth’s atmosphere, and originate from numerous sources, such as lakes, oceans, soils, humans, and animals (Bowers et al., 2012). A recent study revealed more than 1,800 types of bacteria in air samples taken from the Texas cities of San Antonio and Austin, with some of them posing a serious public health hazard (Brodie et al., 2007). Airborne fungal contaminants (molds, yeasts, mush-rooms) present a similar threat to humans, being occasionally associated with dangerous infections and toxicity (Łukaszuk et al., 2011). Therefore, the airborne germ load in indoor and outdoor environments is essential for the health of employees and visitors (Yu et al., 2009).

Indoor and outdoor air quality, as their names implies, is a term used to assess the quality of the air in offices, laboratories, industries and other building environments (Fanger, 2000). Determination of Indoor and outdoor air quality relies on collection of air samples, monitoring human exposure to pollutants, collection of samples on building surfaces, and computer modeling of air flow inside and ouside the buildings (Klepeis, 2006). There is strong evidence suggesting that airborne microbiota greatly affect Indoor and outdoor air quality. For example, the sick building syndrome (SBS), which includes a large variety of nonspecific symptoms that occurs in the residents of a building (Joshi, 2008), is frequently related to elevated levels to which airborne microorganisms occur in indoor air Indoor and outdoor air quality in typical enclosed and open spaces (Fischer and Dott, 2003).

Microbial damage in indoor/outdoor areas, are caused most frequently by molds and bacteria. These micro-organisms have a very important role in the biogeochemical cycle, as their task consists of disintegrating organic mass to reusable metabolites. In the environment spores of molds and bacteria may become airborne and are therefore ubiquitous. They can enter indoor areas either by means of passive ventilation or by means of ventilation systems. Many genera are also emitted by indoor sources like animals, flowerpots and wastebaskets. In most cases, normal flora is not harmful. However, growth conditions like excessive humidity and/or a high water content of building materials are encountered on a more frequent basis, which in most cases can be described as the limiting factor for microbial growth. This is caused by shortcomings of the buildings such as the lack of thermal insulation, as well as the incorrect behavior of users of rooms. The relative humidity and/ or the moisture content of the materials determine that to what extent different micro-organisms are able to grow on indoor or outdoor materials (Dhanasekaran et al., 2009). These may cause destruction, adverse health effects and unpleasant odors.

Microorganisms such as bacterial and fungal spores are almost always present in the air. The quality of indoor environment, however, is not easily defined or readily controlled, and can potentially place human occupants at risk (Jaffal, et al., 2007). Airborne transmission is one of the routes of spreading diseases responsible for a number of nosocomial infections (Claudete et al., 2006). Reservoirs of pathogens outside of hospitals are also becoming new area of concern. Generally, outdoor air is the dominant source of indoor fungi (Ponce-Caballero et al., 2008). More, interestingly, it has been shown that season can affect the results of an indoor microbial analysis. Reponen and colleagues showed that although the indoor air counts of fungi were significantly lower during winter than other seasons, airborne bacteria did not exhibit clear seasonal pattern (Reponen et al., 2002).  Rintala et al., (2008) reported a clear distinction of the effect of seasons on airborne micro-flora, where the total concentration of culturable microorganisms in indoor air was highest in summer and fall than in winter.

1.1 AIM AND OBJECTIVES

To determine microbiological quality of indoor and outdoor air of Undergraduate Microbiology laboratory in Michael Okpara University of Agriculture, Umudike, while the specific objectives are;

1. To determine the microbial content of air within and outside the Undergraduate Microbiology Laboratory.

2. To isolate and identify air microbes present in and outside this Laboratory.

3. To compare the microbial quality of the two environments.

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