Clinical impact of methicillin resistance on outcome of patients with Staphylococcus aureus infection: a stratified analysis according to underlying diseases and sites of infection in a large prospective cohort.

OBJECTIVE: This study was conducted to identify the predictors of mortality and to evaluate the impact of methicillin resistance on outcome in patients with Staphylococcus aureus infection according to underlying conditions and type of infection. METHODS: An observational cohort study including 4949 patients with S. aureus infection was conducted. We compared data from patients with MRSA infection with those with MSSA infection. RESULTS: The 30-day mortality rate of MRSA group was significantly higher than that of MSSA group (15.6% vs. 6.2%, P < 0.001). However, MRSA infection was not found to be independent risk factor for mortality after adjusting for other variables (OR = 1.03, 95% CI = 0.80-1.32). When we analyzed patients with S. aureus bacteremia (n = 709), MRSA infection was found to be significantly associated with mortality in multivariate analysis (Adjusted OR = 1.69, 95% CI = 1.15-2.49). When the 30-day mortality rates were compared according to underlying diseases, the 30-day mortality rate of MRSA group was significantly higher than that of MSSA group in patients with malignancy or renal diseases. MRSA infection was also found to be one of the independent risk factors for mortality in patients with malignancy (adjusted OR = 1.69, 95% CI = 1.06-2.70) and in those with renal disease (adjusted OR = 1.70, 95% CI = 1.0-2.89), after adjustment for host variables. CONCLUSIONS: Methicillin resistance adversely affected the outcome of patients with S. aureus infection, in patients with cancer or renal disease and in those with S. aureus bacteremia, although MRSA infection was not found to be significantly associated with higher mortality in overall patient population.

Epidemiology and clinical outcomes of community-acquired pneumonia in adult patients in Asian countries: a prospective study by the Asian network for surveillance of resistant pathogens.

Appropriate antimicrobial treatment of community-acquired pneumonia (CAP) should be based on the distribution of aetiological pathogens, antimicrobial resistance of major pathogens, clinical characteristics and outcomes. We performed a prospective observational study of 955 cases of adult CAP in 14 hospitals in eight Asian countries. Microbiological evaluation to determine etiological pathogens as well as clinical evaluation was performed. Bronchopulmonary disease (29.9%) was the most frequent underlying disease, followed by cardiovascular diseases (19.9%), malignancy (11.7%) and neurological disorder (8.2%). Streptococcus pneumoniae (29.2%) was the most common isolate, followed by Klebsiella pneumoniae (15.4%) and Haemophilus influenzae (15.1%). Serological tests were positive for Mycoplasma pneumoniae (11.0%) and Chlamydia pneumoniae (13.4%). Only 1.1% was positive for Legionella pneumophila by urinary antigen test. Of the pneumococcal isolates, 56.1% were resistant to erythromycin and 52.6% were not susceptible to penicillin. Seventeen percent of CAP had mixed infection, especially S. pneumoniae with C. pneumoniae. The overall mortality rate was 7.3%, and nursing home residence, mechanical ventilation, malignancy, cardiovascular diseases, respiratory rate>30/min and hyponatraemia were significant independent risk factors for mortality by multivariate analysis (P<0.05). The current data provide relevant information about pathogen distribution and antimicrobial resistance of major pathogens of CAP as well as clinical outcomes of illness in Asian countries.