Colonization of skilled-care facility residents with antimicrobial-resistant pathogens

J Am Geriatr Soc. 2001 Mar;49(3):270-6. doi: 10.1046/j.1532-5415.2001.4930270.x.


Objectives: To determine the frequency of and risk factors for colonization of skilled-care unit residents by several antimicrobial-resistant bacterial species, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococcus (VRE), or extended-spectrum-beta-lactamase-producing (ESBL-producing) (ceftazidime resistant) Klebsiella pneumoniae or Escherichia coli.

Design: Point-prevalence survey and medical record review.

Setting: The skilled-care units in one healthcare facility.

Participants: 120 skilled-care unit residents.

Measurements: Colonization by each of the four antimicrobial-resistant pathogens during a point-prevalence survey, using rectal, nasal, gastrostomy-tube site, wound, and axillary cultures, June 1-3, 1998; 117 (98%) had at least one swab collected and 114 (95%) had a rectal swab collected. Demographic and clinical characteristics were evaluated as risk factors for colonization. All isolates were strain typed by pulsed-field gel electrophoresis of total genomic deoxyribonucleic acid.

Results: Of 117 participants, 50 (43%) were culture positive for > or =1 antimicrobial-resistant pathogen: MRSA (24%), ESBL-producing K. pneumoniae (18%) or E. coli (15%), and VRE (3.5%). Of 50 residents culture positive for any of these four antimicrobial-resistant species, 13 (26%) were colonized by more than one resistant species; only three (6%) were on contact-isolation precautions at the time of the prevalence survey. Risk factors for colonization varied by pathogen: total dependence on healthcare workers (HCWs) for activities of daily living (ADLs) and antimicrobial receipt for MRSA, total dependence on HCWs for ADLs for ESBL-producing K. pneumoniae, and antimicrobial receipt for VRE. No significant risk factors were identified for colonization by ESBL-producing E. coli. Among colonized patients, there was a limited number of strain types for MRSA (24 patients, 4 strain types) and ESBL-producing K. pneumoniae (21 patients, 3 strain types), and a high proportion of unique strain types for VRE (4 patients, 4 strain types) and FSBL-producing E. coli (17 patients, 10 strain types).

Conclusion: A large unrecognized reservoir of skilled-care-unit residents was colonized by antimicrobial-resistant pathogens, and co-colonization by more than one target species was common. To prevent transmission of antimicrobial-resistant pathogens in long-term care facilities in which residents have high rates of colonization, infection-control strategies may need to be modified. Potential modifications include enhanced infection-control strategies, such as universal gloving for all or high-risk residents, or screening of high-risk residents, such as those with total dependence on HCWs for ADLs or recent antimicrobial receipt, and initiation of contact-isolation precautions for colonized residents.

MeSH terms

  • Aged
  • Bacterial Infections / diagnosis
  • Bacterial Infections / drug therapy
  • Bacterial Infections / epidemiology*
  • Bacterial Infections / microbiology*
  • Colony Count, Microbial
  • Cross Infection / diagnosis
  • Cross Infection / drug therapy
  • Cross Infection / epidemiology*
  • Cross Infection / microbiology*
  • Data Collection
  • Drug Resistance, Microbial*
  • Drug Resistance, Multiple
  • Escherichia coli / isolation & purification
  • Escherichia coli Infections / epidemiology
  • Female
  • Health Care Surveys
  • Hospital Units / standards
  • Hospital Units / statistics & numerical data*
  • Humans
  • Illinois / epidemiology
  • Klebsiella Infections / epidemiology
  • Klebsiella pneumoniae / isolation & purification
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Prevalence
  • Skilled Nursing Facilities / standards
  • Skilled Nursing Facilities / statistics & numerical data*
  • Staphylococcal Infections / epidemiology
  • Staphylococcus aureus / isolation & purification
  • Subacute Care / standards
  • Subacute Care / statistics & numerical data*