The marked increase in the incidence of infections due to antibiotic-resistant gram-negative bacilli in recent years is of great concern, as patients infected by those isolates might initially receive antibiotics that are inactive against the responsible pathogens. To evaluate the effect of inappropriate initial antimicrobial therapy on survival, a total of 286 patients with antibiotic-resistant gram-negative bacteremia, 61 patients with Escherichia coli bacteremia, 65 with Klebsiella pneumoniae bacteremia, 74 with Pseudomonas aeruginosa bacteremia, and 86 with Enterobacter bacteremia, were analyzed retrospectively. If a patient received at least one antimicrobial agent to which the causative microorganisms were susceptible within 24 h of blood culture collection, the initial antimicrobial therapy was considered to have been appropriate. High-risk sources of bacteremia were defined as the lung, peritoneum, or an unknown source. The main outcome measure was 30-day mortality. Of the 286 patients, 135 (47.2%) received appropriate initial empirical antimicrobial therapy, and the remaining 151 (52.8%) patients received inappropriate therapy. The adequately treated group had a 27.4% mortality rate, whereas the inadequately treated group had a 38.4% mortality rate (P ‫؍‬ 0.049). Multivariate analysis showed that the significant independent risk factors of mortality were presentation with septic shock, a high-risk source of bacteremia, P. aeruginosa infection, and an increasing APACHE II score. In the subgroup of patients (n ‫؍‬ 132) with a high-risk source of bacteremia, inappropriate initial antimicrobial therapy was independently associated with increased mortality (odds ratio, 3.64; 95% confidence interval, 1.13 to 11.72; P ‫؍‬ 0.030). Our data suggest that inappropriate initial antimicrobial therapy is associated with adverse outcome in antibiotic-resistant gram-negative bacteremia, particularly in patients with a high-risk source of bacteremia.Gram-negative bacilli such as Enterobacteriaceae and Pseudomonas aeruginosa are the leading causes of nosocomial bloodstream infections. Antibiotic-resistant strains have emerged among the gram-negative bacilli and are being increasingly recognized (8,20). This marked increase in the incidence of infections due to antibiotic-resistant gram-negative bacilli in recent years is of great concern. It is presumed that infections caused by antibiotic-resistant bacteria result in greater mortality, longer hospitalization, and higher costs than infections caused by antibiotic-susceptible bacteria, although little data are available to support this intuitive concept (2, 3, 12). The assumption that infections caused by antibiotic-resistant bacteria are associated with a higher mortality rate is based on the possibility that appropriate antimicrobial therapy for such infections might be initiated later than for infections caused by antibiotic-susceptible bacteria (14).Appropriate antimicrobial therapy has been shown to reduce mortality among patients with gram-negative bacteremia (10, 1...

Among the nosocomial pathogens, Pseudomonas aeruginosa is recognized as a major cause of morbidity and mortality. Data on 136 patients with P. aeruginosa bacteremia were retrospectively analyzed to evaluate risk factors for mortality. The median age of the patients was 55 years (range, 15-85 years), 78.7% of the cases were hospital-acquired, and the 30-day mortality rate was 39% (53 of 136 patients). Multivariate analysis demonstrated that risk factors for mortality included severe sepsis, pneumonia, delay in starting effective antimicrobial therapy, and an increasing APACHE II score (all P values <.05). In 123 of the 136 patients (excluding 13 patients treated with inadequate definitive antibiotics), 30-day mortality was 27.7% (13 of 47 patients) in the group of patients who received initially effective empirical antimicrobial therapy, and 43.4% (33 of 76) in the group of patients who received delayed effective antimicrobial therapy (P=.079). There was a trend toward higher mortality as the length of delay increased. Delay in starting effective antimicrobial therapy for P. aeruginosa bacteremia tended to be associated with higher mortality.

Our findings confirmed that MRSA infections in the community have been increasing in Asian countries. Data also suggest that various MRSA clones have spread between the community and hospitals as well as between countries.

None.