Different Study Methods
According to the available data, the number of participating intensive care units increased by 180 and that of surgical wards by 249, whereas the total increase in cases of nosocomial infection due to Staphylococcus aureus came to 202, with the proportion of MRSA infection reduced from 32.8% to 26.4%. What was not explained was the extent to which the structure of participating institutions might have changed over the time period—that is: has the relative proportion of wards and departments from medical centers offering the complete range of healthcare services, with a high proportion of high-risk patients, fallen as a result of an increase in participation by medical centers with a lower proportion of high-risk patients? Does an association exist between the change in participants and the differences in occurrence in the German federal states? Reviewing the situation under the aspect of population density cannot provide any further clues as to the reasons of the increased proportions of MRSA among the S aureus population if a state such as North Rhine-Westphalia is compared with Mecklenburg-Western Pomerania. Different study methods may also be relevant in terms of the described differences in MRSA rates in south Brandenburg and Saarland (0.8% vs 2.2%) (1, 2). Further possible reasons for regional differences include population structures with regard to age and comorbidity, or the ratio of healthcare personnel to patients. The question of how the epidemiological changes in Barden-Württemberg should be interpreted remains unanswered. The increase in urinary tract infections and “sepsis” between 2011 and 2012 also remains unexplained.
The analysis of infections caused by bacterial pathogens with special resistance mechanisms allows for important insights in dealing with such infections and approaches to preventing them. I doubt whether that would be possible by using the data presented by the authors. The crucial issue has always been the analysis of the local epidemiology, the risk factors for MRSA colonization or infection, the type and extent of screening and hygiene measures, and the engagement of all relevant parties.
Prof. Dr. med. habil. Dr. med.
Wolfgang R. Heizmann
Arzt für Mikrobiologie
|1.||Van Horn KG, Audette CD, Tucker KA, Sebeck D: Comparison of 3 swab transport systems for direct release and recovery of aerobic and anaerobic bacteria. Diagn Microbiol Infect Dis 2008; 62: 471–3. CrossRef MEDLINE|
|2.||Smismans A, Verhaegen J, Schuermans A, Frans J: Evaluation of the Copan ESwab transport system for the detection of methicillin-resistant Staphylococcus aureus: a laboratory and clinical study. Diagn Microbiol Infect Dis 2009; 65: 108–11. CrossRef MEDLINE|
|3.||Meyer E, Schröder C, Gastmeier P, Geffers C: The reduction of nosocomial MRSA infection in Germany—an analysis of data from the Hospital Infection Surveillance System (KISS) between 2007 and 2012. Dtsch Arztebl Int 2014; 111: 331–6.|