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“Colonization Pressure” and Risk of Acquisition of Methicillin-Resistant Staphylococcus aureus in a Medical Intensive Care Unit

  • Jacques Merrer (a1) (a2), François Santoli (a1), Corinne Appéré-De Vecchi (a1), Beatrice Tran (a2), Bernard De Jonghe (a1) and Hervé Outin (a1)...
Abstract
AbstractObjective:

To determine the roles of “colonization pressure,” work load or patient severity in patient acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in intensive care units (ICUs).

Design:

Prospectively collected data from October 1996 through December 1998.

Setting:

A 12-bed medical ICU in a university-affiliated general hospital.

Patients:

Patients with risk factors for MRSA admitted to the ICU were screened within 72 hours of admission and weekly thereafter. MRSA was considered imported if detected during the first 72 hours of admission and nosocomial if detected only thereafter. Three screening strategies were used on admission during three consecutive periods.

Interventions:

The unit of time chosen for measurements was the week. Weekly colonization pressure (WCP) was defined as the number of MRSA-carrier patient-days/total number of patient-days. Patient severity (number of deaths, Simplified Acute Physiologic Score [SAPS] II), work load (number of admissions. Omega score), and colonization pressure (number of MRSA carriers at the time of admission, WCP) were compared with the number of MRSA-nosocomial cases during the following week.

Results:

Of the 1,016 patients admitted over 116 weeks, 691 (68%) were screened. MRSA was imported in 91 (8.9%) admitted patients (13.1% of screened patients) and nosocomial in 46 (4.5%). The number of MRSA-nosocomial cases was correlated to the SAPS II (P=.007), the Omega 3 score (P=.007), the number of MRSA-imported cases (P=.01), WCP (P<.0001), and the screening period (P<.0001). In multivariate analysis, WCP was the only independent predictive factor for MRSA acquisition (P=.0002). Above 30% of WCP, the risk of acquisition of MRSA was approximately fivefold times higher (relative risk, 4.9;95% confidence interval, 1.2-19.9; P<.0001).

Conclusion:

Acquisition of MRSA in ICU patients is strongly and independently influenced by colonization pressure.

Copyright
Corresponding author
Service de Réanimation Médicale, Hôpital de Poissy/St Germain, 10 rue du Champ-Gaillard, 78303 Poissy, France
References
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1.Panlilio AL, Culver DH, Gaynes RP, Banerjee S, Henderson TS, Tolson JS, et al. Methicillin-resistant Staphylococcus aureus in U.S. hospitals, 1975-1991. Infect Control Hosp Epidemiol 1992;13:582586.
2.College de bacteriologie-virologie-hygiene du centre hospitalier universitaire de Paris. Surveillance des staphylocoques dores et klebsielles multiresistants a l'assistance publique—hopitaux de Paris. Bulletin Epidemiologique Hebdomadaire 1998;10:4143.
3.Thompson RL, Cabezudo I, Wenzel RP. Epidemiology of nosocomial infections caused by methicillin-resistant Staphylococcus aureus. Ann Intern Med 1982;97:309317.
4.Goldmann DA, Weinstein RAWenzel RP, Tablan OC, Duma RJ, Gaynes RP, et al. Strategies to prevent and control the emergence and spread of antimicrobial-resistant microorganisms in hospitals. A challenge to hospital leadership. JAMA 1996;275:234240.
5.Wenzel RP, Nettleman MD, Jones RN, Pfaller MAMethicillin-resistant Staphylococcus aureus: implications for the 1990s and effective control measures. Am J Med 1991;91 (suppl 3B):221S227S.
6.Jarvis WR. Preventing the emergence of multidrug-resistant microorganisms through antimicrobial use controls: the complexity of the problem. Infect Control Hosp Epidemiol 1996;17:490495.
7.Carlet J. Quality assessment of intensive care units. Current Opinion in Critical Care 1996;2:319325.
8.An approach to the evaluation of quality indicators of the outcome of care in hospitalized patients, with a focus on nosocomial infection indicators. The Quality Indicator Study Group. Infect Control Hosp Epidemiol 1995;16:308316.
9.Bonten MJ, Slaughter S, Ambergen AW, Hayden MK, van Voorhis J, Nathan C, et al. The role of “colonization pressure” in the spread of vancomycin-resistant enterococci: an important infection control variable. Arch Intern Med 1998;158:11271132.
10.Haley RW, Cushion NB, Tenover FC, Bannerman TL, Dryer D, Ross J, et al. Eradication of endemic methicillin-resistant Staphylococcus aureus infections from a neonatal intensive care unit. J Infect Dis 1995;171:614624.
11.Pittet D, Mourouga P, Perneger TV. Compliance with handwashing in a teaching hospital. Infection Control Program. Ann Intern Med 1999;130:126130.
12.Garner JS. Guideline for isolation precautions in hospitals. The Hospital Infection Control Practices Advisory Committee. Infect Control Hosp Epidemiol 1996;17:5380.
13.Antiobiogram Committee of French Society for Microbiology. Official Statement 1999 (in French). Pathol Biol (Paris) 1999;47:845872.
14.Le Gall JR, Lemeshow S, Saulnier F. A new Simplified Acute Physiology Score (SAPS II) based on a European/North American multicenter study. JAMA 1993;270:29572963.
15.Sznajder M, Leleu G, Buonamico G, Auvert B, Aegerter R Merlier Y, et al. Estimation of direct cost and resource allocation in intensive care: correlation with Omega system. Intensive Care Med 1998;24:582589.
16.Sébille V, Chevret S, Valieron AJ. Modeling the spread of resistant nosocomial pathogens in an intensive-care unit. Infect Control Hosp Epidemiol 1997;18:8492.
17.Bonten MJ, Hayden MK, Nathan C, van Voorhis J, Matushek M, Slaughter S, et al. Epidemiology of colonisation of patients and environment with vancomycin-resistant enterococci. Lancet 1996;348:16151619.
18.Corbella X, Dominguez MA, Pujol M, Ayats J, Sendra M, Pallares R, et al. Staphylococcus aureus nasal carriage as a marker for subsequent staphylococcal infections in intensive care unit patients. Eur J Clin Microbiol Infect Dis 1997;16:351357.
19.Pujol M, Pena C, Pallares R, Ariza J, Ayats J, Dominguez MA, et al. Nosocomial Staphylococcus aureus bacteremia among nasal carriers of methicillin-resistant and methicillin-susceptible strains. Am J Med 1996;100:509516.
20.Girou E, Pujade G, Legrand P, Cizeau F, Brun-Buisson C. Selective screening of carriers for control of methicillin-resistant Staphylococcus aureus (MRSA) in high-risk hospital areas with a high level of endemic MRSA Clin Infect Dis 1998;27:543550.
21.Jernigan JA, Titus MG, Groschel DH, Getehell-White S, Farr BM. Effectiveness of contact isolation during a hospital outbreak of methicillin-resistant Staphylococcus aureus. Am J Epidemiol 1996;143:496504.
22.Coello R, Jimenez J, Garcia M, Arroyo P, Minguez D, Fernandez C, et al. Prospective study of infection, colonization and carriage of methicillin-resistant Staphylococcus aureus in an outbreak affecting 990 patients. Eur J Clin Microbiol Infect Dis 1994;13:7481.
23.Crowcroft NS, Ronveaux O, Monnet DL, Mertens RMethicillin-resistant Staphylococcus aureus and antimicrobial use in Belgian hospitals. Infect Control Hosp Epidemiol 1999;20:3136.
24.Asensio A, Guerrero A, Quereda C, Lizan M, Martinez-Ferrer M. Colonization and infection with methicillin-resistant Staphylococcus aureus: associated factors and eradication. Infect Control Hosp Epidemiol 1996;17:2028.
25.Maistam J, Lind LTherapeutic Intervention Scoring System (TISS)—a method for measuring workload and calculating costs in the ICU. Acta Anaesthesiol Scand 1992;36:758763.
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Infection Control & Hospital Epidemiology
  • ISSN: 0899-823X
  • EISSN: 1559-6834
  • URL: /core/journals/infection-control-and-hospital-epidemiology
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