Extraction and studying the effect of pH and temperature on hemolysin production by a local isolates of Staphylococcus aureus

I. Nadir, Mohammed; S. Al-Hasani, Hussain; H. Al-Shammary, Amer

	Extraction and studying the effect of pH and temperature on hemolysin production by a local isolates of Staphylococcus aureus
Kerbala Journal of Medicine
Article 15, Volume 5, Issue 11, 2012, Pages 1283-1294 PDF (0 K)
Authors
Mohammed I. Nadir; Hussain S. Al-Hasani; Amer H. Al-Shammary
Abstract
background: Staphylococcus aureus is a ubiquitous bacterium that is generating increasingly bad press coverage due to its propensity to adopt a pathogenic lifestyle in hospital and community settings. S. aureus colonies are found in approximately 30% of the general population. It colonizes the skin readily and can lead to a wide range of pathological conditions from skin lesions to osteomyelitis, endocarditis, and septicemia. Many bacteria produce substances that are cytolysins i.e they dissolve red blood cells (hemolysins) or kill tissue cells or leukocytes (leukocidins). The β-toxin degrades sphingomyelin and therefore is toxic for many kinds of cells, including human red blood cells. Hemolysins were extracted and the optimum conditions for their production were extensively studied including optimum pH, temperature, incubation period, and various manipulations of the culture media. Objectives 1-Extraction of hemolysin from a local isolate of S. aureus. 2-Studying the effects of pH and temperature on hemolysin production. Methods : Bacterial samples were identified by subjecting them to the standard laboratory procedures while semi quantitative screening on blood agar (containing 5% human blood) revealed that all isolates were hemolysin producer but in different efficiencies. Determination of the optimal conditions for hemolysin production including the optimum pH and temperature were also performed. Results : Bacterial samples were identified by subjecting them to the standard laboratory procedures and the results showed that forty isolates out of the total of 100 were identified as Staphylococcus aureus. Semi quantitative screening on blood agar (containing 5% human blood) revealed that all isolates were hemolysin producer but in different efficiencies. Depending on the semi-quantitative screening and hemolytic assays isolate SW-14 of Staphylococcus aureus was the higher hemolysin producing isolate. Determination of the optimal conditions for hemolysin production including the optimum pH and temperature were performed, the results demonstrated that the best hemolysin production was in the pH near neutrality (pH 7-7.5) and in temperature of 35-40oC. Conclusions 1.Conventional methods can be performed to extract hemolysins. 2.Hemolysin was maximally produced when the pH was near neutrality and incubation temperature was 37oC and this conclusion indicates that hemolysin was produced when the conditions were similar to that of the host.
Keywords
Hemolysin; semi; quatitative screening; temperature

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