Clinical characteristics and prognosis of infections caused by OXA-48 carbapenemase-producing Enterobacteriaceae in patients treated with ceftazidime-avibactam.

BACKGROUND: Ceftazidime-avibactam has in vitro activity against Gram-negative bacilli that produce Class A, C and some D ß-lactamases, and has been successfully used in the treatment of infections caused by cephalosporin and carbapenem-resistant Enterobacteriaceae. However, actual experience in the treatment of OXA-48 carbapenemase-producing Enterobacteriaceae (CPE) is limited. OBJECTIVE: To review the characteristics and prognosis of OXA-48 CPE infections treated with ceftazidime-avibactam since introduction of the drug to the current centre during the period October 2014 to December 2016. METHODS: Retrospective assessment of episodes of infection caused by OXA-48 CPE treated with ceftazidime-avibactam, analysing data collected from infection diagnosis until 90 days after the end of treatment. RESULTS: Twenty-four episodes were analysed. Ceftazidime-avibactam was given as the initial definitive treatment in 15 (62.5%) and as salvage therapy in nine (37.5%). Intraabdominal (seven, 29%), urinary (six, 25%) and respiratory (five, 21%) were the most common sources. The 30-day and 90-day mortality rates were 8.3% and 20.8%, respectively. Clinical cure at 30 days was achieved in 62.5% of episodes. Four (16.7%) patients had adverse events, two of them were related to impaired renal function. Among patients who finished the treatment with ceftazidime-avibactam, seven (35%) were diagnosed with infection recurrence within 90 days of the end of treatment. CONCLUSIONS: From experience, ceftazidime-avibactam is an effective drug for treating infections due to OXA-48 CPE. From these results a better safety profile than the current best available therapy could be expected.

Evaluation of ceftazidime/avibactam for serious infections due to multidrug-resistant and extensively drug-resistant Pseudomonas aeruginosa.

OBJECTIVES: The steady progress in resistance of Pseudomonas aeruginosa (PA) has led to difficulties in treating infections due to multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains. Ceftazidime/avibactam (CAZ/AVI) has in vitro activity against many of these strains, however clinical experience with CAZ/AVI is limited. This study aimed to evaluate the characteristics and outcomes of eight patients with infections due to MDR- or XDR-PA treated with CAZ/AVI, including four strains resistant to ceftolozane/tazobactam. METHODS: This was a retrospective descriptive study of patients admitted to a teaching hospital between January 2016 and May 2017 who received CAZ/AVI as initial or continuation therapy for infection due to MDR- and XDR-PA. RESULTS: The sources of infection were hospital-acquired lower respiratory tract infection in five patients (62.5%) and osteomyelitis, meningitis and catheter-related bacteraemia in one patient each. Clinical cure was achieved in 4 patients (50.0%). The 30-day and 90-day mortality rates were 12.5% and 37.5%, respectively. One patient (12.5%) developed encephalopathy that improved with discontinuation of the drug. CONCLUSIONS: CAZ/AVI may be a valuable option for serious infections due to resistant PA.

A propensity score analysis shows that empirical treatment with linezolid does not increase the thirty-day mortality rate in patients with Gram-negative bacteremia.

The role of linezolid in empirical therapy of suspected bacteremia remains unclear. The aim of this study was to evaluate the influence of empirical use of linezolid or glycopeptides in addition to other antibiotics on the 30-day mortality rates in patients with Gram-negative bacteremia. For this purpose, 1,126 patients with Gram-negative bacteremia in the Hospital Clinic of Barcelona from 2000 to 2012 were included in this study. In order to compare the mortality rates between patients who received linezolid or glycopeptides, the propensity scores on baseline variables were used to balance the treatment groups, and both propensity score matching and propensity-adjusted logistic regression were used to compare the 30-day mortality rates between the groups. The overall 30-day mortality rate was 16.0% during the study period. Sixty-eight patients received empirical treatment with linezolid, and 1,058 received glycopeptides. The propensity score matching included 64 patients in each treatment group. After matching, the mortality rates were 14.1% (9/64) in patients who received glycopeptides and 21.9% (14/64) in those who received linezolid, and a nonsignificant association between empirical linezolid treatment and mortality rate (odds ratio [OR], 1.63; 95% confidence interval [CI], 0.69 to 3.82; P = 0.275, McNemar's test) was found. This association remained nonsignificant when variables that remained unbalanced after matching were included in a conditional logistic regression model. Further, the stratified propensity score analysis did not show any significant relationship between empirical linezolid treatment and the mortality rate after adjustment by propensity score quintiles or other variables potentially associated with mortality. In conclusion, the propensity score analysis showed that empirical treatment with linezolid compared with that with glycopeptides was not associated with 30-day mortality rates in patients with Gram-negative bacteremia.