Sludge Watch ==> Community Acquired MRSA Strains - Supplanting Hospital Acquired MRSA Strains

[Maureen Reilly]

Sludgewatch admin:

We know that bacteria pick up antibiotic resistance in the journey through 
the sewage treatment process.  At the end of the pipe..the sewage effluent 
and the sewage sludge (biosolids) end up with bacterial populations with 
significant antibiotic resistance.

These resistant bacteria are in the sludge materials we are delivering to 
food lands and in the wastewater effluents we are sending into the 
environment to lakes and rivers.  Resistant bacteria also found in reclaimed 
water that is used for recharging drinking water aquifers. urban watering,  
and for irrigation.

Mixing our fecal wastes with antibiotics, letting the 'superbugs' propagate 
in the 'treatment system' and then releasing these pathogens into the 
environment.  Is this the best we can do?

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Medscape
April 9, 2008

Community-Associated MRSA Strains May Be Supplanting Traditional Nosocomial 
Strains


By Scott Baltic

NEW YORK (Reuters Health) Apr 03 - Community-associated strains of 
methicillin-resistant Staphylococcus aureus (MRSA) were responsible for an 
increasing proportion of all nosocomial MRSA cases over a 7-year period at a 
large inner-city hospital, according to a retrospective study reported in 
the March 15 issue of Clinical Infectious Diseases.

The researchers note, however, that their study also found that, so far, the 
community-associated strains are presenting no more of a danger to patients 
than the traditional, hospital-associated strains.

Dr. Kyle Popovich, at Stroger Hospital of Cook County, Chicago, and 
colleagues first updated an established algorithm that uses antibiotic 
susceptibility (to clindamycin and/or ciprofloxacin) and results from 
pulsed-field gel electrophoresis to infer the genotypes of MRSA strains. 
They then applied this rule to all 208 hospital-onset (more than 72 hours 
after admission) MRSA isolates between January 2000 and December 2006.

Although the total incidence density rates for MRSA bloodstream infections 
were relatively stable over the study period, the risk for hospital-onset 
MRSA infections due to community genotype (CG) strains increased (risk ratio 
1.9, p = 0.01), while the risk for infections due to hospital genotype (HG) 
strains decreased (risk ratio 0.7, p = 0.02).

Between the period January 2000 - June 2003 and the period July 2003 - 
December 2006, the proportion of cases due to CG strains doubled from 24% to 
49%.

The evaluated clinical outcomes, including duration of bacteremia, length of 
hospital stay, hospital readmission within 3 months and all-cause 
in-hospital mortality, were similar between patients infected with 
traditional hospital strains and those with community-associated strains.

"While our study showed similarities between CG and HG strains," Dr. 
Popovich told Reuters Health, "studies have shown virulent community MRSA 
strains exist leading to necrotizing skin infections, pneumonia and 
bacteremia. Since community MRSA strains are entering the hospital, 
additional research into appropriate infection control strategies to reduce 
transmission and infection is needed."

In an accompanying editorial, Dr. John M. Boyce of Yale University School of 
Medicine gives a variety of recommendations for improving infection-control 
measures in hospitals, among them making personnel "aware that patients 
infected with MRSA are usually colonized at multiple body sites (including 
normal-appearing areas of skin) and that they often contaminate items in 
their immediate vicinity."


Clin Infect Dis 2008;46:787-794.


http://www.medscape.com/viewarticle/572483?src=mp&spon=3&uac=37242BG