Risk factors for pneumonia due to beta-lactam-susceptible and beta-lactam-resistant Pseudomonas aeruginosa: a case–case–control study

Changes in Emergency Department Visits, Diagnostic Groups, and 28-Day Mortality Associated With the COVID-19 Pandemic: A Territory-Wide, Retrospective, Cohort Study

STUDY OBJECTIVE

We aimed to evaluate and characterize the scale and relationships of emergency department (ED) visits and excess mortality associated with the early phase of the COVID-19 pandemic in the territory of Hong Kong.

METHODS

We conducted a territory-wide, retrospective cohort study to compare ED visits and the related impact of the COVID-19 pandemic on mortality. All ED visits at 18 public acute hospitals in Hong Kong between January 1 and August 31 of 2019 (n=1,426,259) and 2020 (n=1,035,562) were included. The primary outcome was all-cause mortality in the 28 days following an ED visit. The secondary outcomes were weekly number of ED visits and diagnosis-specific mortality.

RESULTS

ED visits decreased by 27.4%, from 1,426,259 in 2019 to 1,035,562 in 2020. Overall period mortality increased from 28,686 (2.0%) in 2019 to 29,737 (2.9%) in 2020. The adjusted odds ratio for 28-day, all-cause mortality in the pandemic period of 2020 relative to 2019 was 1.26 (95% confidence interval 1.24 to 1.28). Both sexes, age more than 45 years, all triage categories, all social classes, all ED visit periods, epilepsy (odds ratio 1.58, 95% confidence interval 1.20 to 2.07), lower respiratory tract infection, and airway disease had higher adjusted ORs for all-cause mortality.

CONCLUSION

A significant reduction in ED visits in the first 8 months of the COVID-19 pandemic was associated with an increase in deaths certified in the ED. The government must make provisions to encourage patients with alarming symptoms, mental health conditions, and comorbidities to seek timely emergency care, regardless of the pandemic.

Using Prior Culture Results to Improve Initial Empiric Antibiotic Prescribing: An Evaluation of a Simple Clinical Heuristic

BACKGROUND

A patient's prior cultures can inform the subsequent risk of infection from resistant organisms, yet prescribers often fail to incorporate these results into their empiric antibiotic selection. Given that timely initiation of adequate antibiotics has been associated with improved outcomes, there is an urgent need to address this gap.

METHODS

In order to better incorporate prior culture results in the selection of empiric antibiotics, we performed a pragmatic, prospective, hospital-wide intervention: (1) empiric antibiotic prescriptions were assessed for clinically significant discordance with the most recent methicillin-resistant Staphylococcus aureus (MRSA) surveillance swab, previous cultures for extended-spectrum beta-lactamases (ESBLs), and the most recent culture for a Gram-negative (GN) organism; and (2) if discordant, an antimicrobial stewardship pharmacist provided recommendations for alternative therapy. The impact was analyzed using a quasi-experimental design comparing two 9-month periods (pre- and postintervention) at a large academic, tertiary care institution.

RESULTS

Clinically significant discordance was identified 99 times in the preintervention period and 86 times in the intervention period. The proportion of patients that received concordant therapy increased from 73% (72/99) in the control group to 88% (76/86) in the intervention group (P = .01). The median time to concordant therapy was shorter in the intervention group than the control group (25 vs 55 hrs, respectively; P < .001; adjusted hazard ratio = 1.95 [95% confidence interval {CI}, 1.37-2.77; P < .001]). The median duration of unnecessary vancomycin therapy was reduced by 1.1 days (95% CI, .5-1.6 days; P < .001).

CONCLUSIONS

This intervention improved prescribing, with a shorter time to concordant therapy and an increased proportion of patients receiving empiric therapy concordant with prior culture results. The use of unnecessary vancomycin was also reduced.

Application of Standardized Antimicrobial Administration Ratio as a Motivational Tool within a Multi-Hospital Healthcare System

The standardized antimicrobial administration ratio (SAAR) is a novel antimicrobial stewardship metric that compares actual to expected antimicrobial use (AU). This prospective cohort study examines the utility of SAAR reporting and inter-facility comparisons as a motivational tool to improve overall and broad-spectrum AU within a three-hospital healthcare system. Transparent inter-facility comparisons were deployed during system-wide antimicrobial stewardship meetings beginning in October 2017. Stakeholders were advised to interpret the results to foster competition and incorporate SAAR data into focused antimicrobial stewardship interventions. Student’s t-test was used to compare mean SAARs in the pre- (July 2017 through October 2017) and post-intervention periods (November 2017 through June 2019). The mean pre-intervention SAARs for hospitals A, B, and C were 0.69, 1.09, and 0.60, respectively. Hospital B experienced significant reductions in SAAR for overall AU (from 1.09 to 0.83; p < 0.001), broad-spectrum antimicrobials used for hospital-onset infections (from 1.36 to 0.81; p < 0.001), and agents used for resistant gram-positive infections in the intensive care units (from 1.27 to 0.72; p < 0.001) after the interventions. The alignment of the SAAR across the health-system and sustained reduction in overall and broad-spectrum AU through implementation of inter-facility comparisons demonstrate the utility in the motivational application of this antimicrobial use metric.

Use of Antibiotics in Chronic Obstructive Pulmonary Disease: What is Their Current Role in Older Patients?

Chronic obstructive pulmonary disease (COPD) has considerable morbidity and mortality in the older adult population. The role of antibiotics in the management of acute exacerbations of COPD (AECOPD) is currently evolving. Despite only mild benefits, most patients with AECOPD in ambulatory settings receive antibiotics based on clinical criteria. Utilization of point-of-care C-reactive protein (CRP) has reduced antibiotic prescriptions by 20% without compromising clinical outcomes. A strict protocol allowing antibiotic use only in patients with clinical criteria and CRP ≥ 20 mg/L has the potential to reduce antibiotic prescriptions for AECOPD in ambulatory settings by nearly 50%. Amoxicillin and doxycycline are commonly prescribed for AECOPD based on a favorable benefit-to-risk ratio. Prophylactic antibiotics have also been used in selected patients with severe COPD and frequent exacerbations. The use of continuous or intermittent azithromycin has demonstrated efficacy in reducing the frequency of AECOPD in this population; however, this approach has potential for the development of antibiotic resistance and adverse effects. The use of azithromycin prophylaxis in older patients with frequent AECOPD should be determined on a case-by-case basis after careful review, discussion, and counseling of the potential benefits and risks. The role of continuous doxycycline and pulsed moxifloxacin prophylaxis for frequent AECOPD remains controversial.

Prediction of trimethoprim/sulfamethoxazole resistance in community-onset urinary tract infections

OBJECTIVES

This study aimed to predict trimethoprim/sulfamethoxazole (SXT) resistance in patients with community-onset urinary tract infection (UTI) due to Enterobacteriaceae based on patient-specific risk factors.

METHODS

This was a retrospective case-control study in Prisma Health facilities in central South Carolina, USA, including three community hospitals, affiliated emergency departments and ambulatory clinics, including adult patients with community-onset UTI due to Enterobacteriaceae (1 April 2015 to 29 February 2016). Multivariate logistic regression was used to examine risk factors for SXT resistance.

RESULTS

Among 351 unique patients with community-onset UTI, 71 (20.2%) had SXT-resistant Enterobacteriaceae urinary isolates. Overall, median age was 64 years and 252 (71.8%) were female. A multivariate model identified prior urinary infection/colonisation with SXT-resistant Enterobacteriaceae (OR=8.58, 95% CI 3.92-18.81; P<0.001) and SXT use within past 12 months (OR=2.58, 95% CI 1.13-5.89; P=0.02) as predictors of SXT resistance among urinary isolates. Most patients with UTI (285; 81.2%) had no risk factors for SXT resistance. SXT resistance rates increased from 13% in the absence of risk factors to 31% in patients with prior SXT use, 66% in those with prior urinary infection/colonisation with SXT-resistant Enterobacteriaceae and 73% in the presence of both risk factors.

CONCLUSION

SXT resistance in Enterobacteriaceae urinary isolates may be predicted based on prior urine culture results and SXT use within the previous year. Utilisation of a patient-specific antibiogram may allow empirical SXT use in patients with community-onset UTI in the absence of risk factors for resistance.

Syndrome-specific versus prospective audit and feedback interventions for reducing use of broad-spectrum antimicrobial agents

BACKGROUND

Antimicrobial use (AU) of antipseudomonal β-lactams (APBL) has significantly increased over the past decade in US hospitals. This retrospective cohort study compares 2 common antimicrobial stewardship strategies, syndrome-specific interventions and antimicrobial postprescription prospective audit and feedback (PAF), in reducing AU of APBL at a large community-teaching hospital.

METHODS

Four antimicrobial stewardship interventions targeting APBL were serially introduced, including 2 syndrome-specific interventions (bloodstream and intra-abdominal infections) and 2 PAF interventions (carbapenems and piperacillin/tazobactam). Multivariable linear regression was used to examine overall AU of APBL and audited antimicrobial agents.

RESULTS

Overall AU of APBL declined from 92.4-69.1 days of therapy (DOT) per 1,000 patient-days between February 2013 and July 2017 (P < .001). Both syndrome-specific interventions were associated with significant reduction in AU of APBL (-7.7 [95% confidence interval (CI): -11.5, -4.0] and -6.0 [95% CI: -9.7, -2.3] DOT per 1,000 patient-days) for bloodstream and intra-abdominal infections, respectively). No significant change in overall AU of APBL was observed after implementation of PAF interventions for carbapenems (-1.4 [95% CI: -7.4, 4.6] DOT per 1,000 patient-days) or piperacillin/tazobactam (0.9 [95% CI: -3.7, 5.4] DOT per 1,000 patient-days).

CONCLUSIONS

Implementation of syndrome-specific interventions was followed by significant reduction in AU of APBL in this population. Despite reducing AU of targeted agents, neither PAF intervention contributed to overall observed decline in APBL use, likely due to compensatory increase in using other APBL.

Direct Measurement of Performance: A New Era in Antimicrobial Stewardship

For decades, the performance of antimicrobial stewardship programs (ASPs) has been measured by incidence rates of hospital-onset Clostridioides difficile and other infections due to multidrug-resistant bacteria. However, these represent indirect and nonspecific ASP metrics. They are often confounded by factors beyond an ASP’s control, such as changes in diagnostic testing methods or algorithms and the potential of patient-to-patient transmission. Whereas these metrics remain useful for global assessment of healthcare systems, antimicrobial use represents a direct metric that separates the performance of an ASP from other safety and quality teams within an institution. The evolution of electronic medical records and healthcare informatics has made measurements of antimicrobial use a reality. The US Centers for Disease Control and Prevention’s initiative for reporting antimicrobial use and standardized antimicrobial administration ratio in hospitals is highly welcomed. Ultimately, ASPs should be evaluated based on what they do best and what they can control, that is, antimicrobial use within their own institution. This narrative review critically appraises existing stewardship metrics and advocates for adopting antimicrobial use as the primary performance measure. It proposes novel formulas to adjust antimicrobial use based on quality of care and microbiological burden at each institution to allow for meaningful inter-network and inter-facility comparisons.

Multidrug Resistant Gram-Negative Bacteria in Community-Acquired Pneumonia

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2019. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2019. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Utility of Combination Antimicrobial Therapy in Adults with Bloodstream Infections due to Enterobacteriaceae and Non-Fermenting Gram-Negative Bacilli Based on In Vitro Analysis at Two Community Hospitals

This study examined the utility of combination therapy for bloodstream isolates of Enterobacteriaceae and non-fermenting Gram-negative bacilli (NFGN) from adults at two community hospitals from January 2010 through to June 2015. Changes to in vitro antimicrobial susceptibilities by adding ciprofloxacin or gentamicin to third-generation cephalosporins (3GC) were examined overall and in patients with risk factors for 3GC resistance. Overall ceftriaxone susceptibility among Enterobacteriaceae was 996/1063 (94%) and 247/295 (84%) in patients with 3GC resistance risk factors. Susceptibilities increased marginally by adding ciprofloxacin or gentamicin (mean difference 2.4% (95% CI 1.5, 3.4) and 3.0% (95% CI 2.0, 4.0), respectively, overall and 5.4% (95% CI 2.8, 8.0) and 7.1% (95% CI 4.2, 10.1), respectively, in patients with risk factors). Eighty-three of 105 (79%) NFGN were susceptible to ceftazidime overall and 20/29 (69%) in patients with prior beta-lactam use. Overall mean increase in susceptibilities was 15.2% (95% CI: 8.3, 22.2) and 17.1% (95% CI: 9.8, 24.5) for ciprofloxacin and gentamicin combinations, respectively; and 27.6% (95% CI: 10.3, 44.9) for either one with recent beta-lactam use. In this setting, empirical combination therapy had limited utility for Enterobacteriaceae bloodstream isolates but provided significant additional antimicrobial coverage to ceftazidime for NFGN, particularly in patients with prior beta-lactam use.

Multidrug Resistant Gram-Negative Bacteria in Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) is associated with high morbidity and mortality worldwide [1]. Although several different bacteria and respiratory viruses can be responsible for CAP, Streptococcus pneumoniae (pneumococcus) remains the most common causative pathogen. A small proportion of CAP cases are caused by Gram-negative bacteria, especially Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii and Stenotrophomona maltophilia [2, 3]. The main problem concerning the treatment of Gram-negative bacterial infections is their related antibiotic resistance, reported as multidrug resistant (MDR = resistant to at least one agent in three or more groups of antibiotics), extensively drug resistant (XDR = resistant to at least one agent in all but two or fewer groups of antibiotics) and pan-drug resistant (PDR = resistant to all groups of antibiotics) [4]. This makes the clinical management of pneumonia caused by such pathogens a challenge for physicians. Taking into account the clinical severity that may be associated with CAP caused by Gram-negative bacteria (respiratory failure, bacteremia, shock, acute respiratory distress syndrome [ARDS]) the magnitude of the global health problem is tremendous.