Sludge Watch ==> Community Acquired Methecillen Resistant Staph Aureus (CA-MRSA)

[Maureen Reilly]

Sludgewatch Admin:

More people want to understand the current epidemic of antibiotic resistant 
diseases that are being confered in a community setting.The article below is 
a backgrounder of CA-MRSA

We need to know whether watering parks, golf courses and lawns with 
reclaimed water from the sewage treatment plant is spreading disease.

We know that the reclaimed water has antibiotic resistant bacteria.
Similarly - we know that sewage sludge contains antibiotic resistant 
bacteria.
The National Academy of Sciences told the EPA they needed to study the role 
of biosolids sludge spreading in causing antibiotic resistant disease.

The EPA has not studied it.

.........................


Medscape Infectious Diseases
Expert Column
Community-Acquired Methicillin-Resistant Staphylococcus aureus Infections: 
Changes in Practice Required?
Posted 12/20/2007

Lena M. Napolitano, MD, FACS, FCCP, FCCM

Author Information

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Case Presentation
A teacher presents to the emergency department with a swollen, painful, red 
upper extremity for evaluation. Physical examination confirms a cellulitis 
extending from the hand to the elbow with a 2-cm skin lesion in the 
midforearm that is raised and violaceous in color with some small necrotic 
areas. She has never had a skin infection before. She has no chronic medical 
problems.

Her husband is a healthcare worker and has never had a skin infection. Her 
son is in high school and has had a number of skin infections, initially 
acquired through participation in football. He has received a number of 
antibiotic courses of oral clindamycin in the past year, and he still has 
draining skin lesions present.

Ultrasound examination of the arm reveals a fluid collection under the 
central skin lesion. Incision and drainage was performed with drainage of 
purulent fluid and necrotic debris; a culture was sent; and the wound was 
packed open with clorpactin-moistened gauze. Appropriate empiric antibiotics 
were initiated, and she was admitted to the hospital for systemic 
antibiotics, wound care, and arm elevation with careful monitoring of the 
progression of the cellulitis. Three days later the abscess culture 
confirmed methicillin-resistant Staphylococcus aureus (MRSA).

This is now a common presentation to emergency departments across the United 
States. Your patient has a community-acquired (CA)-MRSA skin and soft-tissue 
infection.

MRSA
MRSA remains a major human pathogen. Traditionally, MRSA infections occurred 
exclusively in hospitals and were limited to immunocompromised patients or 
individuals with predisposing risk factors. In 2003, MRSA accounted for 
64.4% of all S aureus infections in US intensive care units. A recent report 
from the Active Bacterial Core surveillance MRSA investigators examined the 
incidence of invasive MRSA disease from July 2004 through December 2005, 
with 8987 observed MRSA cases and 1598 in-hospital deaths reported. Most 
infections were healthcare-associated (HA)-MRSA, but 5250 (58.4%) were 
community-onset infections and 2389 (26.6%) were hospital-onset infections. 
Community-associated MRSA infections occurred in 1234 (13.7%) of the cohort. 
On the basis of these surveillance data, it was estimated that 94,360 
invasive MRSA infections occurred in the United States in 2005, and these 
infections were associated with death in 18,650 cases.

However, recently there has been an alarming epidemic of CA-MRSA strains 
that can cause a spectrum of disease ranging from uncomplicated skin 
infections to severe infections that can result in necrotizing soft-tissue 
infections and necrotizing pneumonia and death in otherwise healthy humans 
outside of the healthcare setting. The emerging potential danger associated 
with CA-MRSA invasive infections was demonstrated by the deaths of 4 healthy 
children in Minnesota and North Dakota between 1997 and 1999.

CA-MRSA
The US Centers for Disease Control and Prevention (CDC) has defined CA-MRSA 
as having no healthcare risk factors. Persons with MRSA infections that meet 
all of the following criteria likely have CA-MRSA infections:

Diagnosis of MRSA was made in the outpatient setting or by a culture 
positive for MRSA within 48 hours after admission to the hospital


No medical history of MRSA infection or colonization

No medical history in the past year of

Hospitalization, dialysis, or surgery

Admission to a nursing home, skilled nursing facility, or hospice

No permanent indwelling catheters or medical devices that pass through the 
skin into the body.


This is in contrast to HA-MRSA infections, defined as those cases with at 
least 1 healthcare risk factor. More recently, HA-MRSA infections were 
further classified as either "community-onset" (cases with a healthcare risk 
factor but with a positive culture obtained ¡Ü 48 hours after hospital 
admission) or "hospital-onset" (cases with positive culture obtained more 
than 48 hours after admission, regardless of whether they also had other 
healthcare risk factors) ( Table ).

CA-MRSA vs HA-MRSA
CA-MRSA differs from HA-MRSA in several important ways. These include the 
lack of traditional risk factors associated with MRSA among patients, a 
bacterial susceptibility pattern with resistance to fewer classes of 
antimicrobial drugs, and the inclusion of specific virulence factors. 
CA-MRSA strains typically carry the Panton-Valentine leukocidin (PVL) genes, 
which produce cytotoxins that can cause tissue necrosis and leukocyte 
destruction and are associated with community-associated staphylococcal skin 
infections and necrotizing pneumonia. CA-MRSA strains currently circulating 
can also be distinguished, to a certain extent, by molecular typing methods, 
such as pulsed-field gel electrophoresis (PFGE) and multilocus sequence 
typing. It appears that a few strains of S aureus (mostly USA300) are 
responsible for much of the CA-MRSA disease that is seen in the United 
States.

CA-MRSA strains can be highly virulent, and have been documented to cause 
life-threatening necrotizing infections. Many strains of CA-MRSA encode for 
the PVL toxin, a pore-forming cytotoxin associated with necrotic lesions or 
abscess formation. More rarely, CA-MRSA infection can lead to cases of 
serious, life-threatening diseases, such as necrotizing pneumonia, 
necrotizing soft-tissue infections, and purpura fulminans -- which may prove 
fatal.