Ceftazidime, Carbapenems, or Piperacillin-tazobactam as Single Definitive Therapy for Pseudomonas aeruginosa Bloodstream Infection: A Multisite Retrospective Study.

BACKGROUND: The optimal antibiotic regimen for Pseudomonas aeruginosa bacteremia is controversial. Although ß-lactam monotherapy is common, data to guide the choice between antibiotics are scarce. We aimed to compare ceftazidime, carbapenems, and piperacillin-tazobactam as definitive monotherapy. METHODS: A multinational retrospective study (9 countries, 25 centers) including 767 hospitalized patients with P. aeruginosa bacteremia treated with ß-lactam monotherapy during 2009-2015. The primary outcome was 30-day all-cause mortality. Univariate and multivariate, including propensity-adjusted, analyses were conducted introducing monotherapy type as an independent variable. RESULTS: Thirty-day mortality was 37/213 (17.4%), 42/210 (20%), and 55/344 (16%) in the ceftazidime, carbapenem, and piperacillin-tazobactam groups, respectively. Type of monotherapy was not significantly associated with mortality in either univariate, multivariate, or propensity-adjusted analyses (odds ratio [OR], 1.14; 95% confidence interval [CI], 0.52-2.46, for ceftazidime; OR, 1.3; 95% CI, 0.67-2.51, for piperacillin-tazobactam, with carbapenems as reference in propensity adjusted multivariate analysis; 542 patients). No significant difference between antibiotics was demonstrated for clinical failure, microbiological failure, or adverse events. Isolation of P. aeruginosa with new resistance to antipseudomonal drugs was significantly more frequent with carbapenems (36/206 [17.5%]) versus ceftazidime (25/201 [12.4%]) and piperacillin-tazobactam (28/332 [8.4%] (P = .007). CONCLUSIONS: No significant difference in mortality, clinical, and microbiological outcomes or adverse events was demonstrated between ceftazidime, carbapenems, and piperacillin-tazobactam as definitive treatment of P. aeruginosa bacteremia. Higher rates of resistant P. aeruginosa after patients were treated with carbapenems, along with the general preference for carbapenem-sparing regimens, suggests using ceftazidime or piperacillin-tazobactam for treating susceptible infection.

Aminoglycosides use in patients over 75 years old.

OBJECTIVE: to describe aminoglycoside use and nephrotoxicity in patients older than 75 years. DESIGN: retrospective multicenter study. SETTING: hospital department, rehabilitation, long-term care center. POPULATION: patients ≥75 years old treated by aminoglycosides. RESULTS: 184 patients, mean age: 84.4 years (range: 75-101). One hundred and twenty-seven patients received other nephrotoxic drug(s). Gentamicin (70%) and amikacin (30%) were used and the once-daily dosing was preferred (92%). Average treatment period was 2.75 (1-10) days for amikacin and 4.4 (1-30) for gentamicin with average dosage 13.5 and 3.5 mg/kg/day, respectively. The monitoring of maximal plasmatic concentration (Cmax) was done in 37 patients, 9 of them had probabilistic treatment. Only one had a Cmax fulfilling the objective of French recommendations (gentamicin >30 mg/l, amikacin >60 mg/l). When infection was documented, the objective of Cmax >10 × minimal inhibitory concentration of the strain was reached for 27%. Minimal plasmatic concentration was checked in 38% of cases, with adequate value (gentamicin <0.5 mg/l, amikacin <2.5 mg/l) for 37%. At the end of aminoglycoside course, 40 patients increased their serum creatinine >25% of the baseline value. In multivariate analysis, this was associated with treatment length ≥3 days and concomitant use of nephrotoxic drugs. CONCLUSION: aminoglycosides dosing used in elderly patients probably need therapeutic drug monitoring and dose adjustment. Aminoglycosides are used to treat severe infections. One of the most important side effects is nephrotoxicity in oldest patients. To minimise nephrotoxicity, short treatments are necessary and avoiding others nephrotoxic drugs could be relevant.