ROLE OF AIR-CONDITIONERS AND OTHER VENTILATION DEVICES IN THE EPIDEMIOLOGY OF RESPIRATORY TRACT INFECTIONS IN ANAMBRA STATE.

Author: Modebelu Afamefuna Felix
Department: Applied Microbiology
Affiliation: Nnamdi Azikiwe University Awka

Studies on the role of air-conditioners (A/Cs) and other ventilation devices like electric fans (E/Fs) and doors/windows (D/Ws) in the epidemiology of respiratory tract infections (RTIs), in Anambra was carried out. Legionella species, a pneumonia causing bacteria and others like Streptococcus pneumoniae, S. pyogenes and fungi like Aspergillus fumigatus and Candida albicans were looked out for in A/Cs discharge water samples. Four hundred (400ml) of water samples dripping from A/Cs discharge nozzles were separately collected from 45 banks, 61 hospitals and 44 hotels (total of 150 samples). The institutions were selected from the 21 local government areas (LGAs) in the State, using proportionate random sampling technique. Indoor/outdoor micro-environment of 150 apartments using various ventilation devices in the selected establishments were examined with exposed plate method. A/Cs vents, E/Fs blades and D/Ws surfaces in the selected institutions were also swabbed and examined. Nasal swabs of personnel with a history of reoccurring RTIs, who use various ventilation devices were equally examined. Pathogens isolated from the later were subjected to conventional antibiotic susceptibility tests. Efficacies of some medicinal plants against the isolates were also determined. A total of 1,600 questionnaires were distributed to personnel under the influence of various ventilation devices in the 21 LGAs to collect biodata and clinical symptoms where applicable. A total of sixty-five (65) bacterial and fungal isolates from human and environmental sources were subjected to molecular studies to establish the similarity between the isolates. Plasmids profile of Staphylococcal aureus isolates from the human and environmental sources were also studied using 1% agarose gel electrophoresis. Some of the findings are as follows: One hundred and twenty-six (126) bacterial isolates were obtained from the 150 water samples collected from A/Cs in the selected institutions. Legionella species was not isolated. Bacterial isolates from banks were 39(26.0%), hospitals 54(36.0%) and hotels 33(22.0%). Pooled bacterial isolates from the institutions showed that Micrococcus luteus was the dominant bacterial isolate 50(39.7%) and was most frequently isolated from the bank environment. It was followed by Arthrobacter globiformis 36(28.6%) and Staphylococcus epidemidis 30(23.8%). Staphylococcus aureus was the least isolated 10(7.9%) and was found mostly in hospital environment. There was no significant statistical difference in bacterial isolates in air-conditioners’ water samples from banks, hospitals and hotels in Anambra p < 0.05. A total of 88 bacterial isolates were recovered in 135 swab samples collected from surfaces of A/Cs, E/Fs and D/Ws in banks. A/C vents had the highest bacterial isolates 36(26.7%), followed by E/Fs 28(20.7%). The least isolates were collected from D/Ws surfaces 24(17.8%). Pooled bacterial isolates from the 3 institutions showed that A. globiformis 35(39.8%) was most predominant, followed by M. luteus 29 (33.0%), S. epidemidis 15(17.0%). S. aureus was least isolated 9(10.2%). There was no significant statistical difference, in the prevalence of bacterial isolates from A/Cs vents, E/Fs blades and D/Ws surfaces in banks, p < 0.05. Similarly, 63 fungal isolates were obtained from 135 swab specimens from surfaces of A/Cs, E/Fs and D/Ws in banks. Isolates from D/Ws surfaces were highest 27(20.0%), followed by those from A/Cs 25(18.5%). E/Fs surfaces had the least isolates 11(8.2%). Pooled fungal isolates showed that Penicillium chrysogenium was isolated highest 24(39.7%), followed by Aspergillus fumigatus 18(28.6%), Candida albicans 13(20.6%), Aspergillus niger 5(7.9%), while Candida parapsilosis 2(3.2%) was the least isolated. There was no significant statistical difference in the prevalence of fungal isolates, from the swabbed surfaces, p < 0.05. The result of nasal swabs of personnel with a history of reoccurring RTIs showed Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus ducreyi and Staphylococcus aureus. There was no significant statistical difference in bacterial isolates from nasal swabs of male and female personnel, under the influence of air-conditioners in banks, p < 0.05. Gentamicin was observed as the best antibiotic for the treatment of pathogenic bacterial isolates from persons with RTIs in this study. Similarly, Moringa oleifera showed the best medicinal efficacy against the pathogenic bacterial isolates. Collated questionnaires responses from 1480 persons using various ventilation devices, showed that 102 of them make use of A/Cs on regular bases. Twelve (11.8%) of them indicated that it greatly affected their respiratory health negatively. Thirty-eight (37.2%) reported that it does so moderately, while 52(51.0%) were of the opinion, that it has no significant negative effect on them. The agr genotyping of S. aureus isolates using computer-assisted analysis of Multiple Locus Variable number Analysis (MLVA) showed human nasal S. aureus isolates which are related to ventilation devices isolates. Similarly the plasmid studies of the S.aureus isolates, and the molecular typing of A. fumigatus isolates from human and ventilation devices showed significant relationship. Based on the result of the molecular studies which established similarily between the isolates from the human occupants of the various institutions studied and ventilation devices which they use, the researcher recommends the need for caution in the use of such devices, especially the air-conditioners. However, additional research is required to determine the method of colonization of the ventilation devices by microorganisms, their source of nutrient, mode of transmission and infectivity. Issues associated with the use of ventilation devices should be addressed to ensure safety and good health for the populace.

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