J Pure Appl Microbiol, 2019, 13 (2): 975-982 | Article Number: 5560
https://dx.doi.org/10.22207/JPAM.13.2.34 | © The Author(s). 2019
Received: 04/04/2019| Accepted: 04/05/2019 | Published: 22/05/2019
The predominance of bacteria on door handles and computers keyboards in Faculty of Science, University of Kufa in Najaf Governorate was assessed. One hundred samples were collected and cultured for bacterial identification. The occurrence of positive samples was as the following; 95% with both of toilets doors handles and computers keyboards, 90% in laboratories doors handles, 80% in Classrooms doors handles and 75% in offices doors handles. The current study demonstrate a high prevalence rate of aerobic bacteria on different doors handles and computers keyboards in Faculty of Science, University of Kufa. The current study gave a clear view about the microbial contamination of door handles and computer keyboards and the possibility to be one of the main sources of infection in the university environment.
Microbial contamination, Aerobic bacteria, Faculty environment.
Microorganisms could be defined as microscopic organisms, present in nature as multicellular, unicellular, or cell clusters. Micro-organisms prevail widespread with a huge extension and biomass on the earth surface1,2. The human body has a diversity of micro-organisms including bacteria, viruses, fungi, and protozoa. For example, they could be found as a normal flora in the human skin such as Bacteroides, Staphylococci, Oropharynx Streptococci, Anaerobes, Vagina (lactobacilli) and digestive organ (Enteric bacilli)3 while others could be classified as pathogenic microbes. Pathogens are mostly transmitted by feces, causing a major human pathogenic infection and outbreaks of disease (e.g. shigellosis)4.
Contact with a dirty tool (e.g. doors, tables, and toilettes) could transport pathogens from a place to a huge region. For example, contacting with an unhygienic peace in a toilette (e.g. doors handle) in a university could transmit pathogens to general peoples; students, cleaners, and instructors; and causing risky contamination consequences. This could raise a risk of having an unexpected-unknown pathogenic infection from this sources5. The computers keyboards capacity to act as infection sources has been already assessed6. The present study went for taking a gander at the idea of bacterial contaminants confined from collective zones and some common equipment at a University setting.
This study was carried out in Faculty of Science / University of Kufa / Najaf / Iraq.
This work was completed between September 2016 and March 2017. Samples were collected from different sites includes; the toilet door handles, classroom doors handles and computer keyboards using Reynolds and his colleagues method via swab-rinse of the APHA “American Public Health Association”7. Door handles were wiped with moistened sterile swab by peptone water. The swaps were thawed and cultured on MacConkey agar, Nutrient agar, and Brain-hart infusion agar. Depending on the manufacturer prescription the media used in this study were prepared.
Each collected sample was processed to isolation and identification the bacteria by culturing , gram staining, motility , and biochemical tests.
Aseptically, each swap rinsed fluid was inoculated on MacConkey agar, Nutrient agar, and Brain-hart infusion agar. The swaps streaked on the plats then incubated overnight at 37°C and examined8. Firstly, Bacterial isolates were identified by macroscopic examination of their colonies depending on color, size, elevation of margin and surface texture, as well as on their ability to lactose fermentation on MacConkey.
Bacterial Identification Test
Gram staining was done according to the method described in Macfaddin(2000)9.
The hanging drop method as described by in Kohlerschmidt, et al. (2009)10 was used for further identification of the Gram-negative rods.
API20 was carried out according to the manufacturer instructions (Biomeriux, France).
Bacterial contamination percent from contaminated surfaces are presented in tables (1,2,3,4,5 and 6) showed different distribution patterns.
Table 1, showed high range of bacterial colonies in several classrooms particularly in the door handles of classroom No. 3,4,12 and 21. While no bacterial colonies were detected in the classroom No. 1,6,10,11. And with variable colonies count in the other classrooms, with an average of bacterial colonies estimated 73.285 colonies.
Bacterial contamination of classroom doors handles
|Seq.||Classroom Name||Colonies number|
Table 2, showed high range of bacterial colonies in several laboratories door handles particularly in electron microscope lab, tissue culture lab and computer lab. While no bacterial colonies were detected in the lab of cell and thin films. And with variable colonies count in the other laboratories, with an average of bacterial colonies estimated 71.636 colonies.
Bacterial contamination of laboratories doors handles
|Seq.||Laboratory Name||Colonies number|
|1||Cell and thin films||0|
Table 3, showed high range of bacterial colonies in several office door handles particularly in postgraduate unit, coordinator of biology department. While no bacterial colonies were detected in the room of archive No. 1, teachers rooms No. 2,3 in the department of chemistry, teachers room No.4 in the department of ecology, main door in the department ecology and the library. And with variable colonies count in the other offices door handles, with an average of bacterial colonies estimated 74.666 colonies.
Bacterial contamination of office doors handles
|Seq.||Room Name||Colonies number|
|5||Main door in the department of biology||3|
|6||Coordinator room in department of biology||288|
|8||Secretory room-1 of physics department||269|
|9||Secretory room-2 of physics department||9|
|10||Head of Geology department||2|
|11||Main Faculty door||4|
|13||Teachers room-1 (department of physics)||5|
|14||Teachers room-1 (department of biology)||30|
|15||Teachers room-1 (department of chemistry)||280|
|16||Teachers room-2 (department of chemistry)||0|
|17||Teachers room-3 (department of chemistry)||0|
|18||Teachers room-1 (department of ecology)||112|
|19||Teachers room-2 (department of ecology)||88|
|20||Teachers room-3 (department of ecology)||21|
|21||Teachers room-4 (department of ecology)||0|
|22||Main door in ecology department||0|
|23||Planning and Tracking Unit||88|
Table 4, showed high range of bacterial colonies in several toilet doors handles particularly in the department of pathological investigation toilet for men, the department of biology toilet for men No.1,2, women No.2, the department of geology toilet for men No.1, the department of chemistry toilet for men No.1 and the department of physics toilet for men No.2. While no bacterial colonies were only detected in the department of biology toilet for women No.1. And with variable colonies count in the other offices door handles, with an average of bacterial colonies estimated 161.904 colonies.
Bacterial contamination of toilet doors handles
|Seq.||Sample description||Colonies number|
|1||Department of physics (men)||37|
|2||Department of pathological investigation (women)||3|
|3||Department of pathological investigation (men)||361|
|4||Department of biology (men)-1||380|
|5||Department of biology (men)-2||232|
|6||Department of biology (women)-1||0|
|7||Department of biology (women)-2||375|
|8||Department of ecology (men)||110|
|9||Department of ecology (women)||117|
|10||Department of geology (men)-1||355|
|11||Department of geology (women)-1||51|
|12||Department of geology (men)-2||39|
|13||Department of geology (women)-2||55|
|14||Department of chemistry (men)-1||314|
|15||Department of chemistry (men)-2||81|
|16||Department of chemistry (women)-1||93|
|17||Department of chemistry (women)-2||10|
|18||Department of physics (men)-1||297|
|19||Department of physics (men)-2||211|
|20||Department of physics (women)-1||189|
|21||Department of physics (women)-2||90|
Table 5, showed high range of bacterial colonies in several computer keyboards particularly in the secretory of the department of chemistry, property section, binders section, data base section, registration-1,2 and archive-1,2. While no bacterial colonies were only detected in the planning section. And with variable colonies count in the other computer keyboards, with an average of bacterial colonies estimated 128.565 colonies.
Bacterial contamination of computer keyboards
|Seq.||Sample description||Colonies number|
|1||Secretory of the department of ecology||30|
|2||Teachers of the department of ecology-1||26|
|3||Teachers of the department of ecology-2||7|
|4||Secretory of the department of geology||18|
|5||Secretory of the department of chemistry||212|
|6||Teachers of the department of geology-1||113|
|9||Data base section||306|
|10||Legal affairs section||11|
|11||Research and development section||15|
|12||Media section -1||6|
|13||Media section -2||5|
|14||Postgraduate section -1||38|
|15||Postgraduate section -2||10|
The highest incidence of positive specimens were recorded in both toilets doors handles and computers keyboards with more than 95% were positive samples, with a high range of bacterial culture in all samples included in this study estimated about 87% (Tabel 6).
Incidence of positive specimens
Total samples examined
No. of positive samples
Percentage of positive samples
Bacterial contamination load (Fig. 1) showed the highest bacterial load were in the toilets doors handles and computers keyboards, while the lowest load was in laboratories doors handles.
Gram stain differentiation showed 65% of samples gives were gram positive and 35% were gram negative (Fig. 2).
Until the beginning of the 20th century, Infectious diseases constituted the most life-threatening diseases in the world when chronic degenerative diseases started to overwhelm this situation in developed countries11. Door handles and computers keyboards are important reservoirs of microorganisms. This study revealed a high percentage of bacterial contamination on door handles and computers keyboards with considerable number of Gram-negative bacteria (G-ve) and Gram-positive bacteria (G+ve). However, G +ve were found to occur more than G-ve. Most microbiota which isolated from skin were Gram-positive, which would account for their predominance on door handles and computers keyboards.
Depending on the results of this study, it is clear that these samples showed the highest contamination with a percentage of 95% positive samples for toilet doors handles followed by laboratories doors handles with 90% positive samples, classrooms doors handles with 80% positive samples and then office doors handles with 75% positive samples. The result of this study shows many types of the microorganisms present. Some of which are human pathogens such as “Staphylococcus aureus, Klebsiella spp., E coli, Proteus spp. and Salmonella spp.”, while another are an opportunistic pathogen such as Staphylococcus spp. Most of the gram-negative bacilli isolated were enteric bacteria in their origin suggestive of oral-fecal contamination and can give rise to foodborne infections and diarrhea. Other organisms isolated can cause certain infections include infection of wound, skin and infection of urinary tract, genital tract, and respiratory tract, as well as typhoid fever dysentery and gastroenteritis12. Seeing a large numbers and different types of bacteria found on door handles and computer keyboards at the Faculty of Science, which calls for interference from students, employees and all door and computer users because they are in danger of being infected.
The study showed a statistically significant difference in this regard. Out of 100 samples processed, 87% showed bacterial contamination.
This is in agreement with the reports of Nworie and his colleagues13 who observed 86.7% and with Onwubiko and Chinyeaka14 who observed 86% bacterial contamination and slightly lower than the reports from London15 who observed 95% positive cultures. This variation in the number of positive samples from one place to the other may not be unconnected with differences in sanitary and hygiene conditions in the environment. In this study, the level of contamination was high. The lower level of contamination in Laboratories and offices doors handles could be attributed to the fact that they are not being used as frequently as other places studied, this is in agreement with the findings of Boone and Gerba16 and Nworie and his colleagues13, who reported that the variation in contamination levels based on the traffic, environment and exposure.
In this study, the most frequently isolated pathogenic bacteria was Staphylococcus aureus which may be due to the fact that it is a major component of the microbiota of the nostrils and skin, which may be explain its high prevalence as a contaminant, as it can easily be settled by several human activities. This observation is in agreement with the findings of other researchers13,17,18.
The microorganisms isolated from toilet door handles in this study were S.aureus, Streptococcus spp, Bacillus spp, E. coli, Proteus and Klebsiella spp. However, the reports from Beaugerie, and Petit3 showed isolated micro-organisms as; Staphylococcus spp., Klebsiella spp, E. coli, and Proteus spp. but from toilet door handles at secondary schools in Chris, and his colleagues19 reported the presence of the bacterial isolates such as S. aureus, and E. coli from the bathroom of students at the University of Miami USA. While Opere and his colleagues20 also reported the isolation of Bacillus spp, S. aureus, S. epidermidis, Micrococcus, Pseudomonas and Enterococcus feacalis from public toilets. Each of these organisms has been implicated either as the most pathogenic bacteria recovered or as a major contaminant. The fact that bacteria of the enterobacteriaceae were regularly found on different door handles may indicate faecal contamination of the hands as the origin21,22. A high percentage of Bacillus spp. was isolated from this research, which actually, it explained that in nature, Bacillus spp. are ubiquitous with their ability to resist environmental changes by spores formation, withstand dry at certain chemical disinfectants and heat for moderate periods.
This is also in agreement with the research carried out by Brooks and his colleagues19 who reported that Bacillus spp was found to be the predominant organism that was isolated from door handles.
Our study showed microbial contaminations, found on computer keyboard surfaces, that effect multiple-users. For example, contamination possibilities by individuals, carrying bacteria, such Staphylococcus aureus was high. Moreover, it was also found that isolated microorganisms able to be viable and persist for a period of time on these surfaces. It is suggested that computer keyboards and door handles in a institution probably act as a tool for pathogenic organisms transmission23.
The University, Health ministry, related offices, through the appropriate agencies, should also set a standard and from time to time in such organization, it must be monitor the practices, as this will go a long way in reducing micro-biological and other hazards associated with contaminated surfaces.
We recommended that clean hands as well as having hygiene tools must be adopted whenever doors handles and computers keyboards will be used in order to reduce the microbial transmission.
The procedure of cleansing is to diminish the microbial load on the strong surfaces. Microorganisms are all over the place, including the air around us, it is along these lines extraordinarily suggested that hand-washing cleanliness ought to be received prior and then afterward utilizing the entry ways handles and PCs consoles to diminish the microbial transmission.
We conclude that there was a less awareness about hygienic manner importance at the location of study, including usage of doors handles and keyboards. This could raise risks of these surfaces to act as sources of potential pathogens. Therefore, we need to enhance awareness of public health sector to awake their responsibilities including public awareness enhancement using lectures, seminars, and training workshops about potential risks in using of contaminated surfaces by reducing cross-transmission fungal and bacterial infections risks.
The authors are thankful to department of Ecology in College of Science, University of Kufa. The authors thank the students, employees and lecturers accommodating in samples collection.
Conflicts Of Interest
The authors declare that there is no conflicts of interest.
All authors have made substantial, direct and intellectual contribution to the work and approved it for publication.
All datasets generated or analyzed during this study are included in the manuscript.
This article does not contain any studies with human participants or animals performed by any of the authors.
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