Rev Esp Quimioter 2013:26(4):337-345

Staphylococcus aureus infections and factors associated with resistance to methicillin in a hospital emergency department 


Objective. Assessment of the characteristics of patients with Staphylococcus aureus (SA) infections, and factors associated with resistance to methicillin in a hospital emergency department (ED) in Spain.
Materials and Methods. All adult patients admitted between January 2007 and December 2010 with a SA infection confirmed by a positive culture in a sample obtained in the hospital emergency department were selected for enrolment. Epidemiological, clinical, therapeutic and microbiological variables were retrospectively collected from the patients’ medical charts. The variable assessed within the primary outcome of the study was the isolation of methicillin resistant Staphylococcus aureus (MRSA). For the purpose of the analysis, the sample was divided in terms of the presence or not of the resistance to methicillin and a logistic regression analysis was performed to identify the factors associated with isolation and empirical antibiotic coverage of MRSA.
Results. A total of 207 patients with a confirmed SA infection were included in the study analysis, with a mean age of 64.7 (SD 20) years. MRSA was isolated in a total of 63 (30.4%) patients, and a linear incremental trend was observed over the course of the study (p=0,047). MRSA was empirically covered in the emergency department on an average rate of one in three patients. Independent factors associated with the isolation of MRSA were: age above 65 years [OR 2.97 (95% CI 1.24 to 7.1), P = 0.014], severe baseline functional dependence [OR 2.41 (95 % 1.02 to 5.69), P = 0.045], chronic obstructive pulmonary disease [OR 4.83 (95% CI 1.88 to 12.42), P = 0.001], history of antibiotic treatment within the previous 2 months [OR 4.94 (95% CI 2.27 to 10.76), P <0.001] and a confirmed urinary infection [OR 5.98 (95% CI 1.65 to 21.69) p = 0.007]. Independent factors associated with empiric coverage of MRSA in the ED were history of antibiotic treatment within the previous 2 months [OR 3.88 (95% CI 1.76 to 8.57), P <0.001] and the presence of a catheter device [OR 6.28 (95% CI 1.64 to 24.07), P = 0.007].
Conclusions. Resistance to methicillin appears to be increasingly frequent in patients infected with SA admitted in our emergency department and there appears to be a need for a more optimal empiric antibiotic treatment in these patients.

Rev Esp Quimioter 2013:26(4):337-345 [pdf]