Farklý inkübasyon koþullarýnýn ve kültür ortamlarýnýn havadaki bakteri ve mantar düzeyine etkisi

Havadaki bakteri ve mantarlarýn örneklenmesinde kullanýlan besiyerlerinin seçimi, bakteri ve mantarlarýn nitel ve nicel olarak doðru belirlenmesine etki eden en önemli faktördür. Bu çalýþmada, 8 ayrý besiyeri türü kullanýlarak Ýzmir kent merkezi havasýnda eþ zamanlý bakteri ve mantar örnekleri toplanmýþtýr. Bakteri örnekleri, Columbia blood agar (CBA), Chocolate agar (Choc), Tryptone Glucose Yeast Extract Agar (TGEA), Reasoner's 2A agar (R2A) ve Plate Count Agar (PCA) besiyerleri üzerinde toplanmýþ ve bu örneklere iki farklý inkübasyon sýcaklýðý ve süresi uygulanarak bakterilerin geliþimi 2 gün boyunca 37ᵒC ve 2 ile 15 gün arasýnda 50ᵒC sýcaklýkta takip edilmiþtir. Mantar örnekleri için ise Malt-Extract Agar (MEA), Dichloran Rose Bengal Chloramphenicol (DRBC) ve Potato Dextrose Agar (PDA) besiyerleri kullanýlmýþtýr. Bunlarýn tamamý ise 25ᵒC’de 3–7 gün inkübe edilmiþtir. Ýnkübasyon süreleri sonunda besiyerlerinde üreme gözlenen koloni sayýlarý ve toplam bakteri ve mantar konsantrasyonlarý belirlenmiþtir. Ýnkübasyon sýcaklýðýnýn PCA hariç (p>0.05) diðer besiyerlerinde toplam bakteri konsantrasyonlarýný etkilediði belirlenmiþtir. Üç besiyerinde toplanan mantar örneklerinde en çok gözlenen cins Cladosporium sp’dir. Koloni sayýlarý bakýmýndan besiyerleri PDA>MEA>DRBC þeklinde sýralanmýþtýr. Mantarlar arasýnda Chrysosporium sp. cinsinin MEA besiyerinde oluþturduðu koloni sayýsý, PDA ve DRBC besiyerlerindekinden yaklaþýk 10 kat daha fazladýr. Eþ zamanlý toplanan örnekler için kullanýlan besiyerlerinde maksimum sayýda izole edilen mantar cinsi sýralamasý MEA>DRBC>PDA þeklindedir. Bu çalýþma, incelediði besiyeri ve inkübasyon koþullarý çeþitliliði ile gelecekte kentsel bölgelerde yapýlacak bakteri ve mantar örneklemelerine yön göstereceði gibi ekstrem koþullara (50ᵒC) dayanabilen havadaki dirençli mikroorganizmalarýn farklý inkübasyon koþullarý altýnda konsantrasyonlarýnýn belirlendiði ilk çalýþma niteliðindedir. Ayrýca, bu çalýþma son yýllarda Dünya Saðlýk Örgütü’nün Antimikrobiyal Direnç tehdidine karþý ülkeleri mücadeleye davet etmesi sebebiyle de önemlidir.

The effect of different incubation conditions and culture media on airbone bacteria and fungi level

The choice of culture media used for airborne bacteria and fungi sampling is the most critical factor that quantitatively affects the determination of bacteria and fungi. In this study, simultaneous bacterial and fungal samples were collected in the air of Izmir city center using eight different media types. Bacterial samples were collected on Columbia blood agar (CBA), Chocolate agar (Choc), Tryptone Glucose Yeast Extract Agar (TGEA), Reasoner's 2A agar (R2A) and Plate Count Agar (PCA) media, and these samples were conditioned at two different incubation temperatures and periods. The growth of bacteria was followed at 37ᵒC for 2 days and at 50ᵒC between 2 and 15 days. Malt-Extract Agar (MEA), Dichloran Rose Bengal Chloramphenicol (DRBC) and Potato Dextrose Agar (PDA) media were used for fungi samples. All fungal samples were incubated at 25ᵒC for 3-7 days. At the end of the incubation period, the number of colonies and total bacteria and fungi concentrations was determined. The incubation temperature was determined to affect the total bacteria concentrations in other media except for PCA (p>0.05). Cladosporium sp was the most frequently observed genus in fungal samples collected on three media. In terms of colony numbers, the media were sorted as PDA>MEA>DRBC. Among the fungi, the number of colonies of Chrysosporium sp. formed in the MEA medium was approximately ten times higher than in PDA and DRBC. The order of the maximum number of isolated fungi in the media used for the samples collected simultaneously is MEA>DRBC>PDA. This research is the first study to determine the concentrations of stable bacteria and fungi that can withstand extreme conditions (50ᵒC) under different incubation conditions, as it will guide future airborne microorganism sampling in urban areas with the variety of media and incubation conditions it has examined. In addition, this study is also important because the World Health Organization has invited countries to fight against the threat of Antimicrobial Resistance in recent years.