SuperBUG

On 15.1.08, BBC reported a new deadly strain of Methicillin Resistant strain of Staphylococcus aureus (MRSA) -Staphylococcus aureus subsp. aureus USA300 has emerged.
The first MRSA strain was discovered in 1961 and the USA300 strain was first isolated from a patient on 1st March 2001. Staphylococcus aureus USA300 strain is now the dominant form of Staphylococcus infection in the US.

MRSA infections used to be confined to hospitalized patients. But in the late 1990s, people began contracting them in community settings - in gyms, jails, schools and even at home; transmitting through skin to skin contacts.

With every turn, this aggressive and persistent bug keeps getting worse and the latest variant of Staphylococcus aureus USA300 - FPR3757 is already found to be resilient to treatment of six major front line antibiotics. The infection is currently treatable with some antibiotics, most importantly vancomycin but researchers fear it is close to acquiring resistance to that drug too.

In the US, MRSA USA300 has moved beyond the borders of US hospitals, and is already spreading into the wider community in San Francisco, Boston, New York and Los Angeles.

Initially, the main reservoir for this MRSA USA300 infection is the injection-drug users, jail inmates and the homeless. Today it is also infecting suburban moms, executives, doctors, athletes of contact sports like wrestling and children. It has turned up in tattoo parlors and newborn nurseries. People with HIV infection seem especially prone to it, but it also strikes patients, gay and straight, who have no previous health problems. Currently, MRSA USA300 is reported to be spreading prevalently amongst homosexuals through sex.

According to the report in the Annals of Internal Medicine, sexually active gay men in San Francisco are 13 times more likely to be infected than their heterosexual neighbours.

Conventionally, most carriers of Staphylococcus carry the bug in their noses but this new community-based MRSA of USA300 also can live in and around the anus and is passed between sexual partners.

Hence, making skin contact with a large number of different people and having lots of sexual partners helps the infection to spread. The best way to reduce the risk of transmission; according to Dr Binh Diep- a researcher at the University of California, San Francisco is probably to wash thoroughly with soap and water, especially after sexual activities.

Staph infections are usually treatable but can be lethal.

The evolved MRSA USA300 strain is dangerous because if the bugs enter the body through a wound in the skin, the toxic proteins that it carries will cause the rare but frighteningly fast skin- and muscle-tissue destruction ("flesh-eating") - a condition known as necrotizing fasciitis; forcing doctors to amputate fingers, toes and limbs.

In other severe cases, it can lead to fatal blood poisoning (septicemia) or necrotising pneumonia (flesh eating form of pneumonia).


****Background of Staphylococcus *****

Domain: Bacteria
Kingdom:Bacteria
Phylum:Firmicutes
Class:Bacilli
Order:Bacillales
Family:Staphylococcaceae
Genus:Staphylococcus

Straphylococci

- In Greek staphyle means bunch of grapes and coccos means granule. The genus Staphylococcus are pathogens of humans and other mammals. Traditionally they were divided into two groups based on the coagulase reaction. Staphylcocci are generally found inhabiting the skin and mucous membranes of mammals and birds. Some members of this genus can be found as human commensals and these are generally believed to have the greatest pathogenic potential in opportunistic infections.

Staphylococcus aureus - This organism is a major cause of nosocomial (hospital-acquired) and community-acquired infections. Since its discovery as an opportunistic pathogen, S. aureus continues to be a major cause of mortality and is responsible for a variety of infections including, boils, furuncles, styes, impetigo and other superficial skin infections in humans. Also known to cause more serious infections particularly in the chronically ill or immunocompromised. These include pneumonia, deep abscesses, osteomyelitis, endocarditis, phlebitis, mastitis and meningitis. The ability to cause invasive disease is associated with persistence in the nasal cavity of a host.

(Key Source: BBC, Wikipedia, San Francisco Chronicle)