Controlling Nosocomial Spread of MRSA
Controlling Nosocomial Spread of MRSA
Methicillin resistant Staphylococcus aureus (MRSA) is an important cause of nosocomial infections. The dynamics of MRSA transmission in health-care settings is characterized by high fluctuations in patient prevalence within units, resulting from patient-to-patient spread and admissions of colonized patients. So far, almost all interventions have been based on implementing barrier precautions for patients with documented MRSA carriage, sometimes in combination with decolonization of carriage. The evidence for the efficacy of patient isolation to control nosocomial spread of MRSA in high endemicity settings, though, is rather limited.
Especially for MRSA, health care workers (HCWs) might be important in the nosocomial transmission dynamics. First, temporary contaminated hands of HCWs are important vectors for MRSA transmission, and appropriate hand hygiene is considered the key intervention to minimize this transmission mode. Second, HCWs may become persistently colonized with MRSA, e.g., in the nose or on injured skin, and act as a constant source for MRSA transmission. The obvious difference between both transmission roles is that hand hygiene will not clear persistent carriage.
MRSA eradication therapies using mupirocin and chlorhexidine were extremely efficacious in decolonizing HCWs. If persistent carriage among HCW is an important source for MRSA transmission, decolonization of HCWs could be effective in controlling MRSA among patients. To the best of our knowledge, though, the relative contribution of persistently colonized HCWs in the epidemiology of MRSA endemicity has never been determined, and, consequently, there is no information on the possible effects of decolonizing persistently colonized HCWs. In contrast the efficacy of eradication therapies applied to patients during hospitalization seems to be low. Clinical decision making for the most appropriate infection control strategy is frequently hampered by the absence of prospective comparisons of different control strategies. Moreover, even if performed, the importance of stochastic events in small populations, such as in hospitals, would necessitate long periods of follow-up. In the absence of empirical evidence, mathematical models may offer the best alternative to determine the optimal control strategy.
Here, we use a computer simulation model to quantify the effects of patient isolation and antimicrobial treatment of carriage for patients and HCWs, as part of an infection control program for MRSA with universal hospital admission screening. We aim to identify scenarios in which HCW decolonization could be considered a sensible intervention.
Background
Methicillin resistant Staphylococcus aureus (MRSA) is an important cause of nosocomial infections. The dynamics of MRSA transmission in health-care settings is characterized by high fluctuations in patient prevalence within units, resulting from patient-to-patient spread and admissions of colonized patients. So far, almost all interventions have been based on implementing barrier precautions for patients with documented MRSA carriage, sometimes in combination with decolonization of carriage. The evidence for the efficacy of patient isolation to control nosocomial spread of MRSA in high endemicity settings, though, is rather limited.
Especially for MRSA, health care workers (HCWs) might be important in the nosocomial transmission dynamics. First, temporary contaminated hands of HCWs are important vectors for MRSA transmission, and appropriate hand hygiene is considered the key intervention to minimize this transmission mode. Second, HCWs may become persistently colonized with MRSA, e.g., in the nose or on injured skin, and act as a constant source for MRSA transmission. The obvious difference between both transmission roles is that hand hygiene will not clear persistent carriage.
MRSA eradication therapies using mupirocin and chlorhexidine were extremely efficacious in decolonizing HCWs. If persistent carriage among HCW is an important source for MRSA transmission, decolonization of HCWs could be effective in controlling MRSA among patients. To the best of our knowledge, though, the relative contribution of persistently colonized HCWs in the epidemiology of MRSA endemicity has never been determined, and, consequently, there is no information on the possible effects of decolonizing persistently colonized HCWs. In contrast the efficacy of eradication therapies applied to patients during hospitalization seems to be low. Clinical decision making for the most appropriate infection control strategy is frequently hampered by the absence of prospective comparisons of different control strategies. Moreover, even if performed, the importance of stochastic events in small populations, such as in hospitals, would necessitate long periods of follow-up. In the absence of empirical evidence, mathematical models may offer the best alternative to determine the optimal control strategy.
Here, we use a computer simulation model to quantify the effects of patient isolation and antimicrobial treatment of carriage for patients and HCWs, as part of an infection control program for MRSA with universal hospital admission screening. We aim to identify scenarios in which HCW decolonization could be considered a sensible intervention.
