Rafidain Journal of Science

Abstract

Four hundred samples were collected from various sources (healthy skin of human, diabetics, thalassemic, turbculosis patients and soil, air samples) for the period from August 2011 to February 2012. One hundred twenty four isolates belonging to Micrococcus spp., Citrococcus spp., Kocuria spp. were identified to species level and classified depending on 90 morphological, Biochemical, Physiological and Molecular characteristics.
The highest rate of isolation was 49.2% which belonged to the species Micrococcus luteus and then 16.1% to M.lylae, followed by 8.9% to Kocuria varians and 8% to both of M.antarcticus, M.endophyticus, K.rhizophila 4.8%, K.kristinae 2.4%, two isolates of Citrococcus spp. 1.6% and one isolate of K.polaris 0.8%. Numerical classification by cluster analysis was carried out and six methods of clustering were compared of which the farthest neighbor linkage method proved to be the most convenient.
The percentage of similarity between the isolates determined using simple matching coefficient (Ssm), so the isolates were grouped into seven main clusters A, B, C, D, E, F,G, and 19 sub clusters. The first main cluster A and the sub clusters B4, B3, B1, C4, C3, C2, C1 included isolates of the species M.luteus, the sub clusters B2, B5 included isolates of the genus Citrococcus spp. and the sub cluster C5 included isolates of the species K.rhizophila, the sub clusters C6 included isolates of the species K.varians, the sub cluster C7 included isolates of the species M.antarcticus, the main cluster D included isolates which belonged to the species K.kristinae, the main cluster E included isolates belonged to the species M.endophyticus, the main cluster F included isolates belonging to the speices M.lylae, the last cluster G included one isolate belonging to the species K.polaris.
Twelve isolates selected from most clusters in hierarchical dendrogram for separation of cellular fatty acids using Gas Liquid Chromatography (GLC) showed that 3 isolates belonging to species M.luteus had the same fatty acid at different concentrations, although they belong to different clusters, also there is heterogencity in present and concentration of fatty acid between the species and this had a major role in the diagnosis of the species M.lylae from M.luteus also have a role in distinguished Citrococcus from the genera Micrococcus and Kocuria, the fatty acid stearic and valeric were absent in all isolates analyzed by GLC which have a role in confirming diagnosis of members of the genus Micrococcus and distinguishing them from the genus Staphylococcus.