Definitive Cefazolin Therapy for Stabilized Adults with Community-Onset Escherichia coli, Klebsiella Species, and Proteus mirabilis Bacteremia: MIC Matters

Abstract

Background: Cefazolin is in vitro active against wild isolates of Escherichia coli, Klebsiella species, and Proteus mirabilis (EKP), but clinical evidence supporting the contemporary susceptibility breakpoint issued by the Clinical and Laboratory Standards Institute (CLSI) are limited. Methods: Between 2010 and 2015, adults with monomicrobial community-onset EKP bacteremia with definitive cefazolin treatment (DCT) at two hospitals were analyzed. Cefazolin minimum inhibitory concentrations (MICs) were correlated with clinical outcomes, including primary (treatment failure of DCT) and secondary (30-day mortality after bacteremia onset, recurrent bacteremia, and mortality within 90 days after the end of DCT) outcomes. Results: Overall, 466 bacteremic episodes, including 340 (76.2%) episodes due to E. coli, 90 (20.2%) Klebsiella species, and 16 (3.6%) P. mirabilis isolates, were analyzed. The mean age of these patients was 67.8 years and female-predominated (68.4%). A crude 15- and 30-day mortality rate was 0.7% and 2.2%, respectively, and 11.2% experienced treatment failure of DCT. A significant linear-by-linear association of cefazolin MICs, with the rate of treatment failure, 30-day crude mortality, recurrent bacteremia or 90-day mortality after the DCT was present (all γ = 1.00, p = 0.01). After adjustment, the significant impact of cefazolin MIC breakpoint on treatment failure and 30-day crude mortality was most evident in 2 mg/L (>2 mg/L vs. ≤2 mg/L; adjusted hazard ratio, 3.69 and 4.79; p < 0.001 and 0.02, respectively). Conclusion: For stabilized patients with community-onset EKP bacteremia after appropriate empirical antimicrobial therapy, cefazolin might be recommended as a definitive therapy for cefazolin-susceptible EKP bacteremia, based on the contemporary CLSI breakpoint.

Prognostic Effects of Delayed Administration of Appropriate Antimicrobials in Bacteraemic Adults Initially Presenting with Various Body Temperatures

“…Bacteraemia was defined as bacterial growth of blood cultures drawn from central or peripheral venipuncture, after exclusion of contaminant sampling. As previously described, 3 , 13 , 14 community-onset bacteraemia indicates that the place of the acquisition of bacteraemia was the community and includes long-term healthcare-associated and community-acquired bacteraemia. The growth of potentially contaminated pathogens on blood cultures, such as coagulase-negative staphylococci, Clostridium perfringens, Micrococcus spp., Bacillus spp., Propionibacterium spp., and Gram-positive bacilli, was regarded as being contaminated, in accordance with previous criteria (shown in Supplemental Box 1 ) 16 .…”

“…For adults attending the ED, data regarding bacterial growth on blood cultures sampled during the ED stay were screened in a computer database. Consistent with previous ED studies, 13 , 15 to accurately collect the patients with “community-onset” bacteraemia, only the first bacteraemia episode was included for those with the multiple episodes of bacteraemia during the study period. Patients with contaminated blood cultures, incomplete clinical information, previously received steroids, antipyretics or antibiotics within 3 days before ED arrival, or transferred from other hospitals were excluded.…”

The Hypotension Period after Initiation of Appropriate Antimicrobial Administration Is Crucial for Survival of Bacteremia Patients Initially Experiencing Severe Sepsis and Septic Shock

“…Blood cultures sampling with potentially contaminating pathogens, such as coagulase-negative staphylococci, micrococci, Bacillus species, Propionibacterium species, and Gram-positive bacilli, were considered to be contaminated based on the previous criteria [8]. Community-onset bacteremia indicates that the onset place of the bacteremia episode is the community [9,10], which includes healthcare-and community-associated bacteremia. The isolation of ≥ two microbial species from a single bacteremia episode was regarded as polymicrobial bacteremia.…”

<p>A Simple Scoring Algorithm That Predicts Abscesses in Adults with Community-Onset <em>Klebsiella pneumoniae</em> Bacteremia: Hypermucoviscosity Matters</p>

“…12 Communityonset bacteremia indicates that the place of the bacteremia onset is inside the community and includes communityacquired and long-term healthcare facility-acquired bloodstream infections. 13,14 Patients were assigned to the abscess group if the bacteremic episode occurred in conjunction with hepatic and/or extra-hepatic abscesses that were diagnosed by imaging and microbiological studies. As previously described, 14,15 the virulence gene magA and the surrounding 33-kb genomic region was demonstrated to be the genetic determinant of capsular serotype K1.…”