Adequacy of empirical antibiotic treatment is an independent risk factor for mortality in patients with E. coli bacteraemia. MDR E. coli bacteraemia had a worse prognosis due, at least in part, to a lower frequency of correct empirical treatment.

Background: previous studies have established that bacterial blood concentration is related with clinical outcome. Time to positivity of blood cultures (TTP) has relationship with bacterial blood concentration and could be related with prognosis. As there is scarce information about the usefulness of TTP, we study the relationship of TTP with clinical parameters in patients with Streptococcus pneumoniae bacteremia.

Restriction fragment length polymorphism (RFLP) was used to study 75 clinical isolates identified as Mycobacterium avium. Two repetitive insertion sequences, IS1311 and IS900, were used as DNA probes. Although less than 25% of isolates showed RFLP patterns with IS900, all strains gave banding patterns with IS1311. M. avium strains isolated from patients with AIDS exhibited marked polymorphism with both probes.

BackgroundThe objective of this study is to analyze the factors that are associated with the adequacy of empirical antibiotic therapy and its impact in mortality in a large cohort of patients with extended-spectrum β-lactamase (ESBL) - producing Escherichia coli and Klebsiella spp. bacteremia.MethodsCases of ESBL producing Enterobacteriaceae (ESBL-E) bacteremia collected from 2003 through 2008 in 19 hospitals in Spain. Statistical analysis was performed using multivariate logistic regression.ResultsWe analyzed 387 cases ESBL-E bloodstream infections. The main sources of bacteremia were urinary tract (55.3%), biliary tract (12.7%), intra-abdominal (8.8%) and unknown origin (9.6%). Among all the 387 episodes, E. coli was isolated from blood cultures in 343 and in 45.71% the ESBL-E was multidrug resistant. Empirical antibiotic treatment was adequate in 48.8% of the cases and the in hospital mortality was 20.9%. In a multivariate analysis adequacy was a risk factor for death [adjusted OR (95% CI): 0.39 (0.31-0.97); P = 0.04], but not in patients without severe sepsis or shock. The class of antibiotic used empirically was not associated with prognosis in adequately treated patients.ConclusionESBL-E bacteremia has a relatively high mortality that is partly related with a low adequacy of empirical antibiotic treatment. In selected subgroups the relevance of the adequacy of empirical therapy is limited.

Of 41 patients with bone-related infections who were treated for > or =10 days with piperacillin-tazobactam, 14 (34%) developed neutropenia. Cumulative doses of piperacillin administered to neutropenic patients were higher than those administered to nonneutropenic ones (330 vs. 237 g; P=.008), and an inverse correlation was detected between the absolute neutrophil count at the end of treatment and the cumulative dose of piperacillin (r=-0.47, P=.002). Moreover, the incidence of piperacillin-tazobactam-induced neutropenia increased with an increase in the cumulative dose of piperacillin: 0% of patients in the first quartile of cumulative piperacillin doses, 33.3% in the second quartile, 40% in the third quartile, and 66.7% in the fourth quartile.