Gram-positive bacilli represent a diverse species of bacteria that range from commensal flora to pathogens implicated in severe and life-threatening infection. Following the isolation of Gram-positive bacilli from blood cultures, the time to species identification may take upward of 24 hours, leaving clinicians to conjecture whether they may represent a contaminant (inadvertent inoculation of commensal flora) or pathogenic organism. In this study, we sought to identify patient variables that could help predict the isolation of contaminant versus pathogenic Gram-positive bacilli from blood cultures.

Retrospective cohort study.

One quaternary academic medical center affiliated with the University of Toronto.

Adult inpatients were admitted to hospital over a 5-year period (May 2014 to December 2019).

A total of 260 unique Gram-positive bacilli blood culture results from adult inpatients were reviewed and analyzed in both a univariable and multivariable model.

Malignancy (aOR 2.78, 95% CI 1.33–5.91, p = 0.007), point increments in the Quick Sepsis Related Organ Failure Assessment score for sepsis (aOR 2.25, 95% CI 1.50–3.47, p < 0.001), peptic ulcer disease (aOR 5.63, 95% CI 1.43–21.0, p = 0.01), and the receipt of immunosuppression prior to a blood culture draw (aOR 3.80, 95% CI 1.86–8.01, p < 0.001) were associated with an increased likelihood of speciating pathogenic Gram-positive bacilli from blood cultures such as Clostridium species and Listeria monocytogenes.

Such predictors can help supplement a clinician’s assessment on determining when empirical therapy is indicated when faced with Gram-positive bacilli from blood cultures and may direct future stewardship interventions for responsible antimicrobial prescribing.

To describe the evolution of respiratory antibiotic prescribing during the coronavirus disease 2019 (COVID-19) pandemic across 3 large hospitals that maintained antimicrobial stewardship services throughout the pandemic.

Retrospective interrupted time-series analysis.

A multicenter study was conducted including medical and intensive care units (ICUs) from 3 hospitals within a Canadian epicenter for COVID-19.

Interrupted time-series analysis was used to analyze rates of respiratory antibiotic utilization measured in days of therapy per 1,000 patient days (DOT/1,000 PD) in medical units and ICUs. Each of the first 3 waves of the pandemic were compared to the baseline.

Within the medical units, use of respiratory antibiotics increased during the first wave of the pandemic (rate ratio [RR], 1.76; 95% CI, 1.38–2.25) but returned to the baseline in waves 2 and 3 despite more COVID-19 admissions. In ICU, the use of respiratory antibiotics increased in wave 1 (RR, 1.30; 95% CI, 1.16–1.46) and wave 2 of the pandemic (RR, 1.21; 95% CI, 1.11–1.33) and returned to the baseline in the third wave, which had the most COVID-19 admissions.

After an initial surge in respiratory antibiotic prescribing, we observed the normalization of prescribing trends at 3 large hospitals throughout the COVID-19 pandemic. This trend may have been due to the timely generation of new research and guidelines developed with frontline clinicians, allowing for the active application of new research to clinical practice.

To evaluate the utility of autologous bone-flap swab cultures performed at the time of cranioplasty in predicting postcranioplasty surgical site infection (SSI).

Retrospective cohort study.

Patients undergoing craniectomy (with bone-flap storage in tissue bank), followed by delayed autologous bone-flap replacement cranioplasty between January 1, 2010, and November 30, 2020.

Tertiary-care academic hospital.

We framed the bone-flap swab culture taken at the time of cranioplasty as a diagnostic test for predicting postcranioplasty SSI. We calculated, sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios.

Among 282 unique eligible cases, 16 (5.6%) developed SSI after cranioplasty. A high percentage of bone-flap swab cultures were positive at the time of craniectomy (66.7%) and cranioplasty (59.5%). Most organisms from bone-flap swab cultures were Cutibacterium acnes or coagulase-negative staphylococci (76%–85%), and most SSI pathogens were methicillin-susceptible Staphylococcus aureus (38%). Bone-flap swab culture had poor sensitivity (0.07; 95% CI, 0.01–0.31), specificity (0.4; 95% CI, 0.34–0.45), and positive likelihood ratio (0.12) for predicting postcranioplasty SSI.

Overall, autologous bone-flap swab cultures performed at the time of cranioplasty have poor utility in predicting postcranioplasty SSI. Eliminating this low-value practice would result in significant workload reductions and associated healthcare costs.

To evaluate different prospective audit-and-feedback models on antimicrobial prescribing at a rehabilitation hospital.

Retrospective interrupted time series (ITS) and qualitative methods.

A 178-bed rehabilitation hospital within an academic health sciences center.

ITS analysis was used to analyze monthly days of therapy (DOT) per 1,000 patient days (PD) and monthly urine cultures ordered per 1,000 PD. We compared 2 sequential intervention periods to the baseline: (1) a period when a dedicated antimicrobial stewardship (AMS) pharmacist performed prospective audit and feedback and provided urine culture education followed by (2) a period when ward pharmacists performing audit and feedback. We conducted an electronic survey with physicians and semistructured interviews with pharmacists, respectively.

Audit and feedback conducted by an AMS pharmacist resulted in a 24.3% relative reduction in total DOT per 1,000 PD (incidence rate ratio [IRR], 0.76; 95% confidence interval [CI], 0.58–0.99; P = .04), whereas we detected no difference between ward pharmacist audit and feedback and the baseline (IRR, 1.20; 95% CI, 0.53–2.70; P = .65). We detected no statistically significant change in monthly urine-culture orders between the AMS pharmacist period and the baseline (level coefficient, 0.81; 95% CI, 0.65–1.01; P = .07). Compared to baseline, the ward pharmacist period showed a statistically significant increase in urine-culture ordering over time (slope coefficient, 1.04; 95% CI, 1.01–1.08; P = .02). The barrier most identified by pharmacists was insufficient time.

Audit and feedback conducted by an AMS pharmacist in a rehabilitation hospital was associated with decreased antimicrobial use.

To assess whether a self-reported β-lactam allergy is associated with an increased risk of surgical site infection (SSI) across a broad range of procedures and to determine whether this association is mediated by the receipt of an alternate antibiotic to cefazolin.

Retrospective cohort study.

Surgical procedures sampled by an institutional National Surgical Quality Improvement Program database over an 18-month period (January 2017 to June 2018) from 7 surgical specialties.

Tertiary-care academic hospital.

Of the 3,589 surgical procedures included in the study, 369 (10.3%) were performed in patients with a reported β-lactam allergy. Those with a reported β-lactam allergy were significantly less likely to receive cefazolin (38.8% vs 95.5%) or metronidazole (20.3% vs 26.1%) and were more likely to receive clindamycin (52.0% vs 0.2%), gentamicin (3.5% vs 0%), or vancomycin (2.2% vs 0.1%) than those without allergy. An SSI occurred in 154 of 3,220 procedures (4.8%) in patients without reported allergy and 27 of 369 (7.3%) with reported allergy. In the multivariable regression model, a reported β-lactam allergy was associated with a statistically significant increase in SSI risk (adjusted odds ratio [aOR], 1.61; 95% confidence interval [CI], 1.04–2.51; P = .03). This effect was completely mediated by receipt of an alternate antibiotic to cefazolin (indirect effect aOR, 1.68; 95% CI, 1.17–2.34; P = .005).

Self-reported β-lactam allergy was associated with an increased SSI risk mediated through receipt of alternate antibiotic prophylaxis. Safely increasing use of cefazolin prophylaxis in patients with reported β-lactam allergy can potentially lower the risk of SSIs.

We aimed to rigorously evaluate the impact of prospective audit and feedback on broad-spectrum antimicrobial use among critical care patients.

Prospective, controlled interrupted time series.

Single tertiary care center with 3 intensive care units.

A formal review of all critical care patients on their third or tenth day of broad-spectrum antibiotic therapy was conducted, and suggestions for antimicrobial optimization were communicated to the critical care team.

The primary outcome was broad-spectrum antibiotic use (days of therapy per 1000 patient-days; secondary outcomes included overall antibiotic use, gram-negative bacterial susceptibility, nosocomial Clostridium difficile infections, length of stay, and mortality.

The mean monthly broad-spectrum antibiotic use decreased from 644 days of therapy per 1,000 patient-days in the preintervention period to 503 days of therapy per 1,000 patient-days in the postintervention period (P < .0001); time series modeling confirmed an immediate decrease (± standard error) of 119 ± 37.9 days of therapy per 1,000 patient-days (P = .0054). In contrast, no changes were identified in the use of broad-spectrum antibiotics in the control group (nonintervention medical and surgical wards) or in the use of control medications in critical care (stress ulcer prophylaxis). The incidence of nosocomial C. difficile infections decreased from 11 to 6 cases in the study intensive care units, whereas the incidence increased from 87 to 116 cases in the control wards (P = .04). Overall gram-negative susceptibility to meropenem increased in the critical care units. Intensive care unit length of stay and mortality did not change.

Institution of a formal prospective audit and feedback program appears to be a safe and effective means to improve broad-spectrum antimicrobial use in critical care.