Title : Clinical efficacy of cefazolin for enterobactriaceae-related infections: A marginal structural model of a retrospective cohort
Abstract:
Cefazolin is useful for gram negative infections, however there are limited data on its clinical effectiveness.
Objectives:
We aim to evaluate clinical efficacy of cefazolin on Enterobacteriaceae infections.
Methods:
This is a retrospective cohort of adults hospitalized between June 1st 2015 to August 31st 2018, with Enterobacteriaceace susceptible to cephalothin or cefazolin isolated from blood, urine and intra-abdominal fluid within 48 hours of admission. Those who received either intravenous cefazolin, ceftriaxone or amoxycillin- clavulanate between Day 2 and Day 4 after cultures and continued for ?3 days were included. Central nervous system infections were excluded. Patients who received cefazolin were compared to those who received amoxycillin-clavulanate (Group 1) or ceftriaxone (Group 2) with respect to time to defervesce (<38 C for 48 hours) and 30-day mortality. Covariates measured were age, gender, prior admission, empiric and concurrent antimicrobial use, Charlson comorbidities index, types of infection, white blood counts, C-reactive protein. Logistic regression model was used to calculate probability of receiving cefazolin in each group factoring in covariates. An inverse probability weighted model was used to assess risk difference of 30-day mortality in each group and bootstrap method for standard errors.
Results:
There were 3963 patients with Enterobacteriaceae isolated from clinical cultures within 48 hours upon admission during the study period.
Of those, 773 patients met inclusion criteria with 87, 162 and 523 patients received intravenous cefazolin, ceftriaxone and amoxycillin- clavulanate as their treatment respectively. 86% of Enterobacteriaceae isolated were Escherichia coli and Klebsiella pneumoniae. Common sites of infection were urinary (61%) and hepatobiliary (19%).
There was no significant difference in time to defervescence of fever in Group 1 (HR 0.84; 95% CI 0.50 – 1.40, p=0.50) and Group 2 (HR 1.09; 95% CI 0.63 – 1.89, p=0.76).
Risk difference of 30-day mortality in Group 1 & Group 2 were - 2.3% (-5.7% - 1.0%, p=0.17) and -1.4% (-6.0% - 3.2%, p=0.56) respectively.
Conclusion:
Cefazolin has similar clinical efficacy in the treatment of infections related to Enterobacteriaceae when compared to amoxycillin- clavulanate and ceftriaxone. Thus, cefazolin should be considered for treatment of clinically significant Enterobacteriaceae infections over other broad-spectrum antimicrobials.
