JOURNAL OF CULTURE COLLECTIONS
Volume 6, 2008-2009, pp. 52-60
COMPARATIVE STUDY ON CHARACTERIZATION OF THREE STAPHYLOCOCCAL ISOLATES FROM VARIED ORIGIN
Poulomi Nandy1, Soumen Roy1, Ashoke Ranjan Thakur3 and Shaon Ray Chaudhuri1,2*
1Department of Biotechnology, West Bengal University of Technology, BF – 142, Sector – 1, Salt Lake, Kolkata 700064, India;
2Humboldt Universitat zu Berlin, Institute for Horticultural Sciences, Department of Urban Horticulture, Lentzeallee 55/57, 14195 Berlin, Germany;
3West Bengal State University (Barasat, North 24 Parganas), Barasat Government College (Annexe Building), 10 KNC Road, Calcutta 700124, India
*Corresponding author, e-mail: shaon.raychaudhuri@gmail.com
Summary
Two strains of Staphylococcus isolated from urine and sputum samples were compared with a laboratory strain of Staphylococcus. Since all three grew on the same media specific for S. aureus, they were studied for their relatedness by morphological, biochemical and molecular characterization. Variation in properties among the isolates pointed towards their different identity which was confirmed through 16S rRNA gene sequence based phylogenetic analysis. The isolate A from urine was found to be closely related to S. haemolyticus, while isolate P from sputum was S. aureus and isolate S from NICED culture collection was closest to S. epidermidis. Thus the Hicrome aureus agar (Himedia M1468) was not specific for the species S. aureus and could only screen at genus level. The antibiotic profile of the strains was evaluated using a spectrum of 18 antibiotics. The lecithinase activity was retained only in freshly isolated strains and totally ceased in subsequent subculturing.
Key words: Staphylococcus aureus, lecithinase, strain characterization, molecular analysis