Community Acquired Methicillan Resistant Staphylococcus Aureus is a recently new super bug that is not found in hospitals but in the outside world. CA-MRSA carries the Panton-Valentine leukocidin (PVL) genes, encoding for cytotoxins that cause tissue necrosis (tissue cell death) and leukocyte (white blood cell) death. Effectively this pathogen is a flesh eating super bug resistant to almost all anti-bacteria presently available. It has the ability to stay alive for long periods in the environment and with every year increasing numbers of deaths are being reported. However, it is not all doom and gloom. Scientists at Dartmouth Medical School have found a gene that encodes for a penicillin binding protein (PBP) allowing the bacteria to be killed. Memmi, the key scientist in the discovery found that by taking out this gene and in essence the proteins it encoded for (PBP4) CA-MRSA resistance to certain anti-bacterial drugs (oxacillin) is almost 0.
A bit about the process- PBP’s are used in strengthening the staphylococcus cell wall and are the proteins that penicillin targets to destroy bacteria. Memmi’s discovery is an important one to dispel “the dogma” that only PBP2a is important. PBP2a is one of the main PBP’s that are immune to the key enzyme B-lactam in penicillin and its derivatives. This allows the PBP2a to strengthen the staphylococcus cell wall and ultimately renders penicillin and its derivatives useless. However, what Memmi and his co-scientists have found is that other PBPs also play a role. The scientists discovered that cefoxitin (a readily available antibiotic) is able to knock out the PBP4 protein and used in conjunction with oxacillin, they were able to kill all strains of CA-MRSA that they came across. This is exciting due to the dangerousness of the bacteria and the fact that there is no sure fire way of killing it.
References:
http://www.nsls.bnl.gov/newsroom/publications/activityreport/2003/pdf/sh_life_sci_3.pdf
http://dartmed.dartmouth.edu/winter08/html/disc_faculty.php
