Effect of ceftazidime/avibactam plus fosfomycin combination on 30 day mortality in patients with bloodstream infections caused by KPC-producing Klebsiella pneumoniae: results from a multicentre retrospective study

Introduction

The primary outcome of the study was to evaluate the effect on 30 day mortality of the combination ceftazidime/avibactam + fosfomycin in the treatment of bloodstream infections (BSIs) caused by KPC-producing Klebsiella pneumoniae (KPC-Kp).

Materials and methods

From October 2018 to March 2021, a retrospective, two-centre study was performed on patients with KPC-Kp BSI hospitalized at Sapienza University (Rome) and ISMETT-IRCCS (Palermo) and treated with ceftazidime/avibactam-containing regimens. A matched cohort (1:1) analysis was performed. Cases were patients receiving ceftazidime/avibactam + fosfomycin and controls were patients receiving ceftazidime/avibactam alone or in combination with in vitro non-active drugs different from fosfomycin (ceftazidime/avibactam ± other). Patients were matched for age, Charlson comorbidity index, ward of isolation (ICU or non-ICU), source of infection and severity of BSI, expressed as INCREMENT carbapenemase-producing Enterobacteriaceae (CPE) score.

Results

Overall, 221 patients were included in the study. Following the 1:1 match, 122 subjects were retrieved: 61 cases (ceftazidime/avibactam + fosfomycin) and 61 controls (ceftazidime/avibactam ± other). No difference in overall mortality emerged between cases and controls, whereas controls had more non-BSI KPC-Kp infections and a higher number of deaths attributable to secondary infections. Almost half of ceftazidime/avibactam + fosfomycin patients were prescribed fosfomycin without MIC fosfomycin availability. No difference in the outcome emerged after stratification for fosfomycin susceptibility availability and dosage. SARS-CoV-2 infection and ICS ≥ 8 independently predicted 30 day mortality, whereas an appropriate definitive therapy was protective.

Conclusions

Our data show that fosfomycin was used in the treatment of KPC-Kp BSI independently from having its susceptibility testing available. Although no difference was found in 30 day overall mortality, ceftazidime/avibactam + fosfomycin was associated with a lower rate of subsequent KPC-Kp infections and secondary infections than other ceftazidime/avibactam-based regimens.

Determinants of prolonged viral RNA shedding in hospitalized patients with SARS-CoV-2 infection

OBJECTIVE

To evaluate determinants of prolonged viral RNA shedding in hospitalized patients with SARS-CoV-2 infection.

MATERIALS AND METHODS

Hospitalized patients with SARS-CoV-2 positive nasopharyngeal RT-PCR were included in a single-center, retrospective study. Patients were divided in 2 groups according to the timing of viral clearance [≤14 days, "early clearance (EC)" and >14 days, "late clearance (LC)"].

RESULTS

179 patients were included in the study (101 EC, 78 LC), with median age 62 years. Median time of viral shedding was 14 days (EC/LC 10 and 19 days, respectively, P < 0.0001). Univariate analyses showed that age, male gender, receiving corticosteroids, receiving tocilizumab, ICU admission, low albumin and NLR ratio were associated with late viral clearance. In the multivariable analysis, older age (P = 0.016), albumin level (P = 0.048), corticosteroids (P = 0.021), and tocilizumab (P = 0.015) were significantly associated with late viral clearance.

CONCLUSIONS

Age, albumin, tocilizumab and corticosteroid treatment were independently associated with a prolonged SARS-CoV-2 RNA shedding.