Community Acquired Methicillin Resistant Staphylococcus Aureus at Fort Benning, GA, 20012005 Force H

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Community Acquired Methicillin Resistant
Staphylococcus Aureus at Fort Benning, GA,
2001-2005 Force Health Protection
ConferenceAlbuquerque, NMAugust 10, 2006

• Presenter Stephanie M. Morrison, MPH,
  Epidemiologist
• Co-authors
• Nikki N Jordan
• LTC Samuel Jang
• James Patrick
• Oak Ridge Institute for Science and Education
• US Army Center for Health Promotion and
  Preventive Medicine
• Martin Army Community Hospital

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Overview

• Background
• Literature review
• Purpose
• Methods
• Results
• Discussion
• Conclusion

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Background
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• Staphylococcus Aureus (Staph)
• Most common skin infection in the United States
• Bacteria on the skin or in the nose of healthy
  people
• 25-30 of the population is colonized
• Most infections are minor seen in the form of
  carbuncles or furuncles
• Can be treated with or without medication

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• Methicillin Resistant Staphylococcus Aureus
  (MRSA)
• Resistance occurred after the introduction of new
  antibiotics
• Described as an infected pimple, insect bite,
  spider bite, or sore
• Colonized in approximately 1 of the population
• Staph strains resistant to beta-lactam
  antibiotics

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Types of MRSA
Healthcare acquired (HA)
Community acquired (CA)
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Health Care Acquired MRSA (HA-MRSA)

• Recent/frequent hospitalization
• Prior/frequent antibiotic use
• Long-term inpatient care

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Community Acquired MRSA (CA-MRSA)

• Not recently hospitalized
• No history of recent medical procedures
• Outbreaks have occurred in a variety of
  populations
• Players of contact sports
• Military members
• Children in daycare
• Prison inmates
• Tattoo participants

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Possible CA-MRSA modes of transmission

• Skin to skin contact
• Crowded Conditions
• Poor Hygiene
• Hands contaminated by contact with
• Colonized or infected individuals
• Colonized or infected body sites of other persons
• Devices, items, or environmental surfaces
  contaminated with body fluids containing staph or
  MRSA.

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Possible risk factors for CA-MRSA

• Other things that make CA-MRSA different from
  HA-MRSA
• Microbiology
• Genotype
• Virulence factor
• Low susceptibility towards Beta-Lactam
  Antibiotics

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Antibiotics with low susceptibility against
CA-MRSA

• Beta Lactam or semi-synthetic beta lactams
• Penicillins
• Oxacillin
• Methicillin
• Cephalosporins
• Keflex
• Others
• Carbapenems
• Imimpenem
• Macrolides
• Azithromycin
• Erythromycin

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Moderately/Highly susceptible antibiotics against
CA-MRSA

• Moderately susceptibple
• Macrolides
• Clarithromycin (Biaxin)
• Quinolones
• Ciprofloxacin
• Levofloxacin
• Gatifloxacin

• Highly susceptible
• Tetracycline
• Clindamycin
• Chlorampenicol
• Rifampin
• Trimethoprim/sulfamethoxazole
• Amino Glycocides
• Amikacin
• Gentamycin
• Glycopeptides
• Vancomycin

• Highly susceptible
• Tetracycline
• Clindamycin
• Chlorampenicol
• Rifampin
• Trimethoprim/sulfamethoxazole
• Amino Glycocides
• Amikacin
• Gentamycin
• Glycopeptides
• Vancomycin

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Previous Prevalence Studies including Military
Populations
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Previous Outbreak Investigations including
Military Populations
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CA-MRSA at Fort Benning

• How did surveillance get started at Ft Benning?

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Purpose

• Determine the CA-MRSA rates at Fort Benning
• Identify antibiotic susceptibility patterns
• Compare findings
• Make recommendations regarding use of antibiotics
  and other ways to prevent CA-MRSA

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Methods
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Cases

• Active Duty (AD)
• BCT trainees, ITB students, post cadre, permanent
  party, and specialized training units
• 1703 men and 30 women from seen at the Martin
  Army Health Center from January 01, 2001 until
  December 31, 2005

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CA-MRSA - Case Definition

• A Case was defined as an AD Soldier with both of
  the following
• Clinically recognized skin or soft tissue
  infection

2. SA culture with identified resistance to
oxacillin or confirmatory resistance to
cefotaxime
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Data Collection

• Medical record review.
• Queried MHS Mart (M2) for population summary data

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Database Variables

• Demographic
• Gender
• Age
• Unit
• Culture date
• Hospitalization admissions
• Wound location
• Antibiotic information
• Prescribed
• Susceptibility tested
• Other info

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Data Analysis

• Descriptive analysis
• MRSA infection rates calculated
• Trend analysis of antibiotic susceptibility

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Results
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Demographic Data
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1,733 total cases - multiple wound sites per
case were observed therefore, columns do not add
to totals Total percentages are based on
exclusion of unknowns
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Days of Hospitalization

• Infections requiring hospitalization
• 218 (11.3)
• Days admitted
• Total1014 Mean 4.6 3.7
• Range 1-33 days

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Rates based on AD monthly MRSA confirmed
positive cultures by monthly AD Ft. Benning
population as derived from M2 (DEERS summary
data)
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Percentage of Staphylococcus Aureus Isolates
Testing Positive for MRSA from 2001-2005
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Percent of Antibiotics Prescribed
Multiple antibiotics may have been prescribed
per case
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Discussion and Conclusion
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Discussion

• Susceptibility patterns compare to patterns in
  other studies.
• Healthcare providers are prescribing the correct
  regimens

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Discussion

• Studies have been done on proper hygiene

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Limitations

• Surveillance artifact.
• Underestimation of rates due to failure to seek
  care.
• Case exposure data was not available.
• Limited demographic and denominator data.
• Full antibiotic susceptibility patterns were not
  available for all MRSA isolates.

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Recommendations

• Improvement of surveillance methods
• Study of risk factors
• Include genotypic and phenotypic testing
• Implement proper hygiene measures
• Suggest a hand sanitizer study in the summer
• Keep suggesting appropriate antibiotic measures

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Conclusion

• The population evaluated was similar to recent
  investigations.
• Risk factor information was not available.
• Correct antibiotics were prescribed over time.
• Surveillance ongoing

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Questions?
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US Army Center for Health Promotion and
Preventive Medicine

• Provide health promotion and preventive medicine
  leadership and services to counter environmental,
  occupational, and disease threats to health,
• fitness, and readiness in support of the National
  Military Strategy