The Development of sample collector for detect microorganisms in the air

Abstract

The small electric sweeper was modified by setting the petri dish holding with the front hole screw head and adjusted the suction speed equally to standard collector (Modified Anderson Sampler). The efficiency of the modified collector in collecting microorganism in the air was studied by collecting bacteria in clinical microbiology laboratory comparing to the standard collector. The result showed that modified collector could collect microorganism in almost the same number of colony count (32 and 35, 15 and 12, 5 and 5) on the same size of media surface (TSA: 38.5 cm²), the modified collector spent less time compared to the standard collector (10 and 30 second). The modified collector was tested in collecting fungi in the air at the clinical fungi laboratory for 10, 20 and 30 second using SDA as collected media plate (78.5 cm²), comparing to conventional method (opening the SDA plate for 20 minute). The result showed that at 30-second operation, the modified collector and collect 1.5 times (14 and 9 colonies) more fungi than opening plate technique and 3 times more species of fungi (6 and 2). The modified collector also spent the time (30 sec and 20 min) 40 times less than opening plate technique. The modified collector was also used to collect the fungi in the air in HIV patient room at Maharaj Nakorn Chiang Mai Hospital compared to opening plate technique. Six rooms of male general medical ward, 6 rooms of female general medical ward and 3 rooms of out patient general medical department were investigated compared to the opening plate technique. It was found that modified collector spent less time (30 sec and 20 min). The result showed that the modified collector could collect and detect more numbers and more species of fungi than opening plate technique (at door point 100 and 59 colonies, 10 and 9 species, 124 and 68 colonies, 11 and 7 species, 91 and 37 colonies and 8 and 5 species, respectively, at bedside 139 and 60 colonies, 11 and 9 species, 128 and 69 colonies, 10 and 6 species and, 97 and 53 colonies, 9 and 7 species, respectively. Moreover, it could detect Penicillium marneffei from 4 different places that could not be detected by opening plate technique. It could be concluded that the modified collector had the efficiency in collecting the microorganism in air better than opening plate method and the results were equally to the standard collector. Moreover, modified collector (5,000 Baht) was 20 times cheaper than the standard collector (120,000 Baht). The development should be studied and scaled up in industrial level to promote its efficiency in collecting the microorganism in air instead of expensive standard collector for the developing country. Bull Chiang Mai Assoc Med Sci 2008; 41: 225-238.