Biofilm formation is a complicated microbiological process and one of the distinctive features of pathogenic bacteria. Biofilms are a cluster of bacterial cells enclosed in extra polymeric substances and irreversibly attached onto a surface. Biofilms have a major impact on public health as biofilm associated bacteria are able to survive and populate in indwelling medical devices, causing severe nosocomial and recurrent infections. Biofilm-embedded bacteria have unique characteristics which are harder to destroy than the planktonic forms. Especially biofilm bacteria are highly resistant to antimicrobial agents. Treating patients undergoing long term urinary catheterization is becoming complicated by encrustation and blockage due to crystalline biofilm formation inside the lumen of catheters. Further, all types of indwelling catheters including silver or nitrofurazone-coated devices are

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Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important causes of hospital infections worldwide. Methicillin-resistant S. aureus (MRSA) tends to be resistant to multiple antibiotics. High-level resistance to antibiotics is caused by the mecA gene, which encodes an alternative penicillin-binding protein, PBP 2a. The present study was aimed to detect mecA in potential Methicillin-resistant Staphylococcus aureus (MRSA) isolates in clinical wastewater. Three hospital wastewater samples were collected and the bacteria were isolated in manitol salt agar (MSA) medium. PCR was performed and sequencing was done to screen the clinical bacterial isolates. Antibiotic resistance was also tested at the levels of 50, 100, 200 and 300 μg/mL ampicillin. The sequences were analyzed using BLAST (NCBI) and EMBOSS Needle tool (EMBL-EBI). DNA extracted from these bacterial isolates amplified further with mecA gene specific primers. Randomly selected two bacterial isolates of Polgahawela hospital effluent were able to grow at 200 μg/mL ampicillin. Sequence analysis of amplified mecA gene product of these two bacterial isolates showed sequence similarity with the penicillin-binding protein (mecA) gene of Staphylococcus aureus strain and methicillin-resistance gene region of Staphylococcus sciuri 28C with 95% and 96% identity respectively. Pairwise alignment results proved 89.6% sequence similarity between the two sequences. In conclusion, potential methicillin resistant staphylococcus aureus (MRSA) along with Staphylococcus sciuri was able to detect only in the clinical effluent collected from Polgahawela base hospital.

Microbial biodegradation of pollutants has intensified in recent years

The basic building blocks of chromatin are referred to as the nucleosome. Nucleosomes play major role in transcriptional regulation, ranging from repression through occlusion of binding sites for transcription factors, to activation through spatial juxtaposition of transcription factor-binding sites. Examining the position of nucleosome in CD80 promoter is essential to detect the mechanism of tissue specific transcriptional regulation at chromatin level. The CD80 is the most potent of all of the co-stimulatory molecule, expressed on the surface of B cells upon antigen stimulation. The expression of CD80 is tightly regulated, normally limited to only a few cell types including B cells. Therefore this study is important, how nucleosomes become positioned during gene regulation in diverse murine tissues and cell lines. The upstream region of CD80 promoter was examined for its nucleosomal organization by low resolution analysis of MNase-southern blot assay. Four nucleosomes were detected in all murine tissues and cells screened for this analysis. Curiously, similar pattern of nucleosome positioning was detected in all the tissues and cell lines screened. This results conclude that there is no regulation at the level of nucleosome positioning in murine CD80 promoter. However, there must be a regulatory mechanism involved in these tissues either at the molecular level or chromatin level or both as the CD80 gene expression was detected in organs rich in antigen presenting cells, spleen, thymus and lung. This was addressed by possible remodeling mechanism through covalent modification of histone proteins which mark for active transcription and repression of gene regulation.