University of Khartoum

Prevalence of Legionella pneumophila in Evaporative Coolers Air Conditioners in Khartoum State

Prevalence of Legionella pneumophila in Evaporative Coolers Air Conditioners in Khartoum State

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Title: Prevalence of Legionella pneumophila in Evaporative Coolers Air Conditioners in Khartoum State
Author: Elsanousi, Reem Mohammed Elfatih Ali
Abstract: This study was designed to detect the prevalence of Legionella pneumophila in evaporative coolers air conditioners in Khartoum State. A total of 525 water samples were collected from water reservoirs of air conditioning systems in the three main cities of Khartoum State (Khartoum, Omdurman and Khartoum North) in the period between March – October, 2012, 2013, 2014, 2015 and 2016. The premises from which the samples were collected were divided into five categories: universities, schools, hospitals, offices and houses (35 samples for each category in the three cities and with a total of 175 samples for each city). Samples were taken according to geographical distribution of the cities including the four directions and following the International Ecological Measures, ethics and microbial quality control measures. Also, water distribution in each area was considered. Five ml of each water sample was centrifuged in a sterile centrifuge tubes at 4000 rpm for 10 minutes. The sediment was inoculated on Buffered Charcoal Yeast Extract Agar Medium (BCYE) and Glycine Vancomycin Polymxin Cycloheximide Medium (GVPC). Inoculated media were incubated at 37 °C, in an atmosphere of 5 -10% CO₂ (using the candle jar) and humidity using wet cotton swamp on water in a Petri Dish, for 3 - 7 days. Suspected Legionella spp. isolates were sub-cultured on blood agar to ensure their negative growth. All the isolates of Legionella species were positive for catalase, oxidase, and gelatin hydrolysis tests. Real- Time PCR was used to confirm the identification of the isolates, which were identical as Legionella pneumophila in cultural, morphological and biochemical characteristics. From a total of 38 selected isolates, 63% were positive for Real Time PCR. Twenty one isolates were subjected to antibiotic sensitivity test. They showed zones of inhibition for ciprofloxacin, azithromycin and erythromycin, while they showed resistance to penicillins and vancomycin. Legionella species were isolated from 222 (42.3%) out of the total samples taken from Khartoum State, which were divided as follows: 75 (33.8%) from Omdurman, 74 (33.3%) from Khartoum North and 73 (32.9%) from Khartoum. Regarding the premises categories, 58 (55.2%) were from hospitals, 52 (49.5%) from offices, 41 (39%) from schools, 38 (36.2%) from houses and 33 (31.4%) from universities were positive for Legionella spp. The highest prevalence rate of Legionella spp. was found in hospitals (55.2%), followed by offices (49.5%), schools (39%), houses (36.2%) and universities (31.4%). The results were subjected to statistical analysis in the form of frequencies and percentages. The significance of these frequencies was tested using chi- square test. Data analysis revealed significant results for Khartoum city (P-value of chi-square=0.002).The data were analyzed using SPSS 21 with reference P-value ≤ 0.05. In conclusion, the rate of the prevalence of Legionella spp. in evaporative cooler air conditioning systems in Khartoum State, found in this study indicates a considerable prevalence of this pathogenic organism in the environment which may result in a great biological burden leading to serious outbreaks if measures of prevention and control are not taken.
URI: http://khartoumspace.uofk.edu/123456789/25617


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