This work offers a plethora of good information about the seriousness of the problem with MRSA as well as other less common but equally serious bacterial strains and how antibiotic over-utilization and patient non-compliance has added tot the problem. In Hughes, D. Andersson, D.I. (2001) book length discussion, Antibiotic Development and Resistance many questions regarding the natural progression of bacterial resistance from the very beginning of antibiotic therapy is discussed. The work details ways in which individual bacterial diseases have progressed as a result of over-utilization of antibacterial (and especially broad spectrum) antibiotics, to treat non-life threatening infections and even viral infections has exacerbated the ineffective nature of antibiotics. The work traces the history of antibiotics and the assumption by many that there will always be a newer and more specific strain of antibiotics available when a new or emerging bacteria arises in the population and is worth a significant look to develop a clearer understanding of the growth and development of the problem.
In one rather fundamental study MRSA is looked at from a community (CA) level, mapping the incidence of CAMRSA into something that then becomes nosocomial or hospital based, with different genetically mutated MRSA infectious agents mixing and becoming even more adaptive. In this empirical review Rutledge (2007) discusses how community acquired strains (those identified 48 or less prior to hospital admissions) and nosocomial infections (those identified 48 hours or longer after hospital admission) are commingling in the hospital setting to become even less clearly identified and more adaptive to resistance.
Coello, Glynn, Gasper, Picazo & Fereres (1997) stress that hospitalized patients have similar empirical risk factors for the development of colonized (non-infection causing) MRSA that then transforms to cause infection as LTC residents.
In hospital outbreaks of methicillin-resistant Staphylococcus aureus (MRSA) many patients are initially colonized without infection. The reasons why some progress to infection while others do not are not known. A cohort of 479 hospital patients, initially only colonized with MRSA, was followed prospectively for the development of MRSA infection. Risk factors for progression to infection were assessed using Cox proportional hazards survival analysis. Fifty-three patients (11 1%) developed 68 MRSA infections. Intensive care setting, administration of three or more antibiotics, ulcers, surgical wounds, nasogastric or endotracheal tubes, drains, and urinary or intravenous catheterization were all associated with increased rates of MRSA infection.
Risk factors for conversion to MRSA infections then become greater as condition deteriorates, and as patients undergo invasive long-term treatments. It is for this reason that screening might need to be universal as colonized patients do not always know they are colonized and the results of such colonization is often unpredictable, with the MRSA laying virtually dormant until it achieves needed conditions for causing infection and transport to preferred areas for infection.
A large population-based study looked at incidence of MRSA and simple S. aureus on a scale of healthy individuals in an attempt to figure out how prevalent colonization with and without infection is in the population. The work was significant in that it made several important observations:
The prevalence of colonization with S. aureus and with MRSA was 31.6% and 0.84%, respectively, in the noninstitutionalized U.S. population. People younger than 65 years of age, men, persons with less education, and persons with asthma were more likely to acquire S. aureus. Persons of black race and those of Mexican birth had lower risk for S. aureus colonization. Persons 65 years of age or older, women, persons with diabetes, and those who were in long-term care in the past year were more likely to have MRSA colonization. Hispanic persons had statistically significantly less risk than white persons. Isolates of MRSA with staphylococcal chromosomal cassette mec type IV (which is often associated with community-associated MRSA) were statistically significantly more likely to be sensitive to erythromycin, clindamycin, and ciprofloxacin. (Graham, Lin & Larson, 2006, p. 318)
The community-based study again indicates the need to screen and treat far more LTC residents than previously believed, as prevention may be one of the only resolutions to the wide spread nature of the problem and to the susceptibility for symptom causing colonization.
Finally the most specific of the empirical studies I located with regard to the LTC population was Strausbaugh, Crossley, Nurse & Thrupp (1996) all members of a LTC committee that studied specific LTC patients and anti-microbial infection risks. These researchers support the idea that the LTC population is at significant risk for MRSA as well as detailing a list of high risk demographics, "serious underlying disease, poor functional status, wounds such as pressure sores, invasive devices such as urinary catheters, and prior antimicrobial therapy." (1996,...
All patients entering the LTCF will sign consent upon entry and will participate in a non-invasive nasal swab culture to determine if they are colonized with MRSA, any classic infections and all disease symptom fluids will also be cultured in those who show symptomology of MRSA upon admission. The work will then trace risk factors for infection conversion, in much the same way as the population-based study above. Increased infection control protocols will be placed on charts and coded on doorways of patients who are colonized to decrease odds of spread of the infection and staff will be briefed to explain the process, research and protocol. Staff will also have nasal swabs, upon consent.
Research Hypotheses
LTC patients with risk factors of: "serious underlying disease, poor functional status, wounds such as pressure sores, invasive devices such as urinary catheters, and prior antimicrobial therapy," (Strausbaugh, Crossley, Nurse & Thrupp 1996, p.129) will have a higher likelihood of disease conversion and colonization. Among patients without disease symptoms colonization will be more likely than would be assumed and preventative treatment may assist in isolating MRSA prior to epidemic spread to non-colonized patients.
Sampling Method Inclusion Criteria
Sampling will be universal upon admission to LTC facility, upon completion of consent by patient or holder of durable medical power of attorney.
Proposed Setting moderate sized LTCF in the region will be utilized as the setting of the study. The hope will be to find a nursing home with no more than 200 beds, and with some affiliation to a hospital, as such transfers seem to be a source of MRSA spread and these coalitions are in need o such a study to understand how they can better deal with inevitable cross contamination of nosocomial and CA infections in vulnerable populations.
Measurement and Instrument
Standard diagnostic cultures will be utilized as measurement instruments for presence of colonization and disease causing MRSA, Review of hospital records as well as patient (family) interviews will also be conducted to help determine possible mode of transmission, i.e. recent (within 2 years) treatments and risk factors for MRSA.
Data Collection
Data will be collected daily, throughout a 12-week period, among all entering and admitted patients.
Data Analysis
Data will be analyzed and collated according to MRSA colonization, and infection conversion.
Demographic Data
Age, gender and disease/condition according to known risk factors will be demographic data.
Confounders
Culture testing will be completed within 12-24 hours of admission, to demonstrate that MRSA was not contracted in the facility. Residents already admitted will also be nasal cultured and developed in the same statistical manner with the inclusion of information on length of admission in data.
Suggested Timetable
The work will be conducted over a 12-week period and results will be collaborative with facility staff, as soon as researchers are made aware of positive cultures staff will be notified and patient chart and doorway will be coded. Upon completion of the 12-week period another 6 weeks will be allowed for the development, analysis and printing of data.
Resources
Coello, R. Glynn, J.R. Gasper, C. Picazo, J.J. & Fereres, J. (1997) "Risk factors for developing clinical infection with methicillin-resistant Staphylococcus aureus (MRSA) amongst hospital patients initially only colonized with MRSA" Elsevier Science http://www.sciencedirect.com/scidirimg/clear.gif doi:10.1016/S0195-6701(97)90071-2
Gorak, E.J. Yamada, S.M. & Brown, J.D. (1999) "Community-Acquired Methicillin-Resistant Staphylococcus aureus in Hospitalized Adults and Children without Known Risk Factors" Infectious Disease Society of America 29 (4) 797-800.
Graham, P.L. Lin, S.X. Larson, E.L. (March 2006) "A U.S. Population-Based Survey of Staphylococcus aureus Colonization," Annals of Internal Medicine. 144(5) 318-325.
Hughes, D. Andersson, D.I. (2001) Antibiotic Development and Resistance.
New York: Taylor and Francis.
Rutledge B.J. (2007) "Community, nosocomial MRSA forms are mixing." Pediatric News.. FindArticles.com. 07 Dec. 2008. http://findarticles.com/p/articles/mi_hb4384/is_1_41/ai_n29321692
Strausbaugh, L.J. Crossley, K.B. Nurse, B.A. & Thrupp, L.D. "Antimicrobial Resistance in Long-Term Care Facilities" Infection Control and Hospital Epidemiology. 17(2) 129-140.
Wenner, M. (August 2008) Next-Generation Antibiotics, Discover29 (8) 11.
Incidence & Risk Factors for MRSA in Long-Term Care
