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

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

Purpose

To investigate the different impact of delayed administration of appropriate antimicrobial therapy (AAT) on short-term mortality of bacteraemia patients initially presenting with various body temperatures (BTs).

Materials and Methods

A six-year, two-center cohort consisting of adults with community-onset bacteraemia in emergency departments (EDs) was retrospectively collected. Through the multivariable analyses, clinical impacts of delayed AAT, assessed by the time gap between the first dose of AAT and ED arrival, on 30-day mortality (primary outcomes) were respectively examined in the different groups of initial BTs (iBTs).

Results

Of the 3171 adults, despite the similarities of delayed AAT in six iBT categories, hourly AAT delay was associated with an average increase in 30-day mortality rates of 0.24% in the group of iBT <36.0℃, 0.40% in the 36.0℃-36.9℃ group, 0.48% in the 37.0℃-37.9℃ group, 0.59% in the 38.0℃-38.9℃ group, 0.58% in the 39.0℃-39.9℃ group, and 0.71% in the ≥40.0℃ group, after respective adjusting independent predictors of mortality. Furthermore, for 589 patients who inappropriately received empirical antimicrobial treatment (ie, delayed AAT ≥ 24 hours), with a cutoff of 34.0℃, each 1℃ increase in iBTs was independently associated with an average increase in 30-day mortality rates of 42%.

Conclusion

For adults with community-onset bacteraemia, the iBT-related differences in the prognostic impacts of delayed administration of appropriate antimicrobials might be evident.

Microorganism Distributions and Antimicrobial Susceptibility in Community-Onset Bacteremia: A 6-Year Longitudinal Multicenter Cohort in Southern Taiwan

BACKGROUND

Prompt administration of appropriate antimicrobials has been correlated with improved prognoses in patients with bacteremia. Because the Clinical and Laboratory Standards Institute (CLSI) has numerously revised the interpretive criteria of susceptibility to numerous antimicrobials, the updated susceptibility is useful for empirical administration.

METHODS

In the multicenter retrospective cohort study consisting of adults with community-onset bacteremia in the emergency department (ED) during the period between January 2010 and December 2015, causative microorganisms were identified by the Vitek 2 system and prospectively collected. Antimicrobial susceptibility were respectively tested by the disk diffusion method for aerobes and the agar dilution method for anaerobes, in accordance with the contemporary CLSI criteria. Clinical information was retrospectively retrieved by reviewing the medical records.

RESULTS

Of the total 3,194 patients and 3,583 causative microorganisms, the leading source of bacteremia was the urinary tract infection (1,034 patients, 32.4%), and Escherichia coli accounted for the majority (1,332 isolates, 37.2%) of the total microorganisms. Overall, the lowest (58.2%) and highest (93.5%) susceptibility to cefazolin and piperacillin/tazobactam were, respectively, observed. In the leading five sources of bacteremia, in terms of the urinary tract infections, pneumonia, intraabdominal infections, skin and soft-tissue infections, and biliary tract infections, cefazolin or cefuroxime was only active against 49.3%-62.3% or 63.2%-74.1% of causative microorganisms, respectively. Notably, E. coli , Klebsiella species, and Proteus mirabilis (EKP) with the production of extended-spectrum beta-lactamases (ESBLs) accounted for 7.4% (142 isolates) of 1,908 EKP and 4.0% of all 3,583 microorganisms; and methicillin-resistant Staphylococcus aureus (MRSA) accounted for 37.7% (158 isolates) of S . aureus and 4.4% of all causative isolates.

CONCLUSIONS

For adults with community-onset bacteremia, a low incidence (approximate 4%) of ESBL-producing EKP and MRSA among all causative microorganisms, but low susceptibility to cefazolin and cefuroxime were recognized. To achieve favorable prognoses by prompt administration of appropriate antimicrobials in EDs, our findings might offer useful information for the antimicrobial stewardship program.

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

Bacteremia is linked to substantial morbidity and medical costs. However, the association between the timing of achieving hemodynamic stability and clinical outcomes remains undetermined. Of the multicenter cohort consisted of 888 adults with community-onset bacteremia initially complicated with severe sepsis and septic shock in the emergency department (ED), a positive linear-by-linear association (γ = 0.839, p < 0.001) of the time-to-appropriate antibiotic (TtAa) and the hypotension period after appropriate antimicrobial therapy (AAT) was exhibited, and a positive trend of the hypotension period after AAT administration in the 15-day (γ = 0.957, p = 0.003) or 30-day crude (γ = 0.975, p = 0.001) mortality rate was evidenced. Moreover, for every hour delay of the TtAa, 30-day survival dropped an average of 0.8% (adjusted odds ratio [AOR], 1.008; p < 0.001); and each additional hour of the hypotension period following AAT initiation notably resulted in with an average 1.1% increase (AOR, 1.011; p < 0.001) in the 30-day crude mortality rate, after adjusting all independent determinants of 30-day mortality recognized by the multivariate regression model. Conclusively, for bacteremia patients initially experiencing severe sepsis and septic shock, prompt AAT administration might shorten the hypotension period to achieve favourable prognoses.

A Critical Review of Cephalexin and Cefadroxil for the Treatment of Acute Uncomplicated Lower Urinary Tract Infection in the Era of "Bad Bugs, Few Drugs"

First-generation oral cephalosporins (cephalexin and cefadroxil) have traditionally been considered second-line treatment options for uncomplicated lower urinary tract infections (uLUTIs).  However, in the current age of "bad bugs, few drugs", where there are increasingly limited oral options against resistant Enterobacteriaceae, there is an urgent need to rethink how best to utilize the available antibiotic armamentarium.  This review examines the historical clinical trials and experimental studies of cephalexin and cefadroxil, particularly through the modern lens of pharmacokinetics/pharmacodynamics (PK/PD), to better appreciate the efficacy of these drugs in uLUTIs.  Furthermore, newer cefazolin-cephalexin surrogate testing, as recommended by the Clinical and Laboratory Standards Institute (CLSI) and the United States Committee on Antimicrobial Susceptibility Testing (USCAST), has recategorized cephalexin in many instances from resistant to susceptible.  We conclude that cephalexin and cefadroxil have very good early bacteriological and clinical cures in uLUTIs due to non-extended-spectrum beta-lactamase-producing (ESBL) Enterobacteriaceae comparable to many traditionally first-line agents.  Cephalexin can be conveniently administered as 500 mg twice or thrice daily, similar to cefadroxil (500 mg twice daily); therefore, either agent may be used as a fluoroquinolone-sparing alternative. Cephalexin may be the more practical choice for many clinicians because reliable antimicrobial susceptibility test interpretative criteria (STIC) are provided by CLSI, USCAST, and the European Committee on Antimicrobial Susceptibility Testing (EUCAST), whereas direct cefadroxil STIC is offered only by EUCAST.

A Simple Scoring Algorithm That Predicts Abscesses in Adults with Community-Onset Klebsiella pneumoniae Bacteremia: Hypermucoviscosity Matters

Introduction

Klebsiella pneumoniae is a pathogen commonly found in community-onset bacteremia. It causes an invasive syndrome that is frequently presented by metastatic infections and abscesses elsewhere and that is necessary for surgical or drainage intervention. To achieve a scoring algorithm to identify patients with community-onset K. pneumoniae bacteremia (CoKPB) who are at risk for abscess occurrences, a retrospective cohort study consisting of adults with CoKPB was conducted.

Methods

A 6-year cohort study consisting of adults having community-onset monomicrobial K. pneumoniae bacteremia was conducted. In addition to clinical variables collected from medical records, the hypermucoviscosity (HMV)-related gene (rmpA and magA) and an HMV phenotype were integrated into the proposed scoring algorithm.

Results

Of the 258 eligible adults, only 79 (30.6%) had abscesses related to bacteremia. Besides the presence of magA (ie, capsular serotype K1) and the HMV-phenotype, five clinical predictors were significantly associated with abscesses in a multivariate analysis: male gender, comorbidities with diabetes mellitus or neurological disorders, recent chemotherapy, and high c-reactive protein levels. Together, these predictors were used to calculate the CoKPB abscess score. Based on the scoring algorithm, a cut-off value of +2 yielded the high sensitivity (93.7%) and the acceptable specificity (50.8%); the area under the ROC curve was 0.83.

Conclusion

A simple scoring algorithm that has substantial sensitivity and satisfactory specificity was proposed and the importance of the HMV phenotype or capsular K1 serotype was emphasized. The proposed predictive model needs external validation, but this scoring algorithm might be convenient and useful for clinicians.