To describe national trends in testing and detection of carbapenemases produced by carbapenem-resistant Enterobacterales (CRE) and associate testing with culture and facility characteristics.

Retrospective cohort study.

Department of Veterans’ Affairs medical centers (VAMCs).

Patients seen at VAMCs between 2013 and 2018 with cultures positive for CRE, defined by national VA guidelines.

Microbiology and clinical data were extracted from national VA data sets. Carbapenemase testing was summarized using descriptive statistics. Characteristics associated with carbapenemase testing were assessed with bivariate analyses.

Of 5,778 standard cultures that grew CRE, 1,905 (33.0%) had evidence of molecular or phenotypic carbapenemase testing and 1,603 (84.1%) of these had carbapenemases detected. Among these cultures confirmed as carbapenemase-producing CRE, 1,053 (65.7%) had molecular testing for ≥1 gene. Almost all testing included KPC (n = 1,047, 99.4%), with KPC detected in 914 of 1,047 (87.3%) cultures. Testing and detection of other enzymes was less frequent. Carbapenemase testing increased over the study period from 23.5% of CRE cultures in 2013 to 58.9% in 2018. The South US Census region (38.6%) and the Northeast (37.2%) region had the highest proportion of CRE cultures with carbapenemase testing. High complexity (vs low) and urban (vs rural) facilities were significantly associated with carbapenemase testing (P < .0001).

Between 2013 and 2018, carbapenemase testing and detection increased in the VA, largely reflecting increased testing and detection of KPC. Surveillance of other carbapenemases is important due to global spread and increasing antibiotic resistance. Efforts supporting the expansion of carbapenemase testing to low-complexity, rural healthcare facilities and standardization of reporting of carbapenemase testing are needed.

As part of a project to implement antimicrobial dashboards at select facilities, we assessed physician attitudes and knowledge regarding antibiotic prescribing.

An online survey explored attitudes toward antimicrobial use and assessed respondents’ management of four clinical scenarios: cellulitis, community-acquired pneumonia, non–catheter-associated asymptomatic bacteriuria, and catheter-associated asymptomatic bacteriuria.

This study was conducted across 16 Veterans’ Affairs (VA) medical centers in 2017.

Physicians working in inpatient settings specializing in infectious diseases (ID), hospital medicine, and non-ID/hospitalist internal medicine.

Scenario responses were scored by assigning +1 for answers most consistent with guidelines, 0 for less guideline-concordant but acceptable answers and −1 for guideline-discordant answers. Scores were normalized to 100% guideline concordant to 100% guideline discordant across all questions within a scenario, and mean scores were calculated across respondents by specialty. Differences in mean score per scenario were tested using analysis of variance (ANOVA).

Overall, 139 physicians completed the survey (19 ID physicians, 62 hospitalists, and 58 other internists). Attitudes were similar across the 3 groups. We detected a significant difference in cellulitis scenario scores (concordance: ID physicians, 76%; hospitalists, 58%; other internists, 52%; P = .0087). Scores were numerically but not significantly different across groups for community-acquired pneumonia (concordance: ID physicians, 75%; hospitalists, 60%; other internists, 56%; P = .0914), for non–catheter-associated asymptomatic bacteriuria (concordance: ID physicians, 65%; hospitalists, 55%; other internists, 40%; P = .322), and for catheter-associated asymptomatic bacteriuria (concordance: ID physicians, 27% concordant; hospitalists, 8% discordant; other internists 13% discordant; P = .12).

Significant differences in performance regarding management of cellulitis and low overall performance regarding asymptomatic bacteriuria point to these conditions as being potentially high-yield targets for stewardship interventions.

To assess the impact of the coronavirus disease 2019 (COVID-19) pandemic on healthcare-associated infections (HAIs) reported from 128 acute-care and 132 long-term care Veterans Affairs (VA) facilities.

We compared central-line–associated bloodstream infections (CLABSIs), ventilator-associated events (VAEs), catheter-associated urinary tract infections (CAUTIs), methicillin-resistant Staphylococcus aureus (MRSA), and Clostridioides difficile infections and rates reported from each facility monthly to a centralized database before the pandemic (February 2019 through January 2020) and during the pandemic (July 2020 through June 2021).

Nationwide VA COVID-19 admissions peaked in January 2021. Significant increases in the rates of CLABSIs, VAEs, and MRSA all-site HAIs (but not MRSA CLABSIs) were observed during the pandemic in acute-care facilities. There was no significant change in CAUTI rates, and C. difficile rates significantly decreased. There were no significant increases in HAIs in long-term care facilities.

The COVID-19 pandemic had a differential impact on HAIs of various types in VA acute care, with many rates increasing. The decrease in CDI HAIs may be due, in part, to evolving diagnostic testing. The minimal impact of COVID-19 in VA long-term facilities may reflect differences in patient numbers and acuity and early recognition of the impact of the pandemic on nursing home residents leading to increased vigilance and optimization of infection prevention and control practices in that setting. These data support the need for building and sustaining conventional infection prevention and control strategies before and during a pandemic.

To determine whether the Society for Healthcare Epidemiology of America (SHEA) and the Infectious Diseases Society of America (IDSA) Clostridioides difficile infection (CDI) severity criteria adequately predicts poor outcomes.

Retrospective validation study.

Patients with CDI in the Veterans’ Affairs Health System from January 1, 2006, to December 31, 2016.

For the 2010 criteria, patients with leukocytosis or a serum creatinine (SCr) value ≥1.5 times the baseline were classified as severe. For the 2018 criteria, patients with leukocytosis or a SCr value ≥1.5 mg/dL were classified as severe. Poor outcomes were defined as hospital or intensive care admission within 7 days of diagnosis, colectomy within 14 days, or 30-day all-cause mortality; they were modeled as a function of the 2010 and 2018 criteria separately using logistic regression.

We analyzed data from 86,112 episodes of CDI. Severity was unclassifiable in a large proportion of episodes diagnosed in subacute care (2010, 58.8%; 2018, 49.2%). Sensitivity ranged from 0.48 for subacute care using 2010 criteria to 0.73 for acute care using 2018 criteria. Areas under the curve were poor and similar (0.60 for subacute care and 0.57 for acute care) for both versions, but negative predictive values were >0.80.

Model performances across care settings and criteria versions were generally poor but had reasonably high negative predictive value. Many patients in the subacute-care setting, an increasing fraction of CDI cases, could not be classified. More work is needed to develop criteria to identify patients at risk of poor outcomes.

Antibiotics are overprescribed for acute respiratory tract infections (ARIs). Guidelines provide criteria to determine which patients should receive antibiotics. We assessed congruence between documentation of ARI diagnostic and treatment practices with guideline recommendations, treatment appropriateness, and outcomes.

A multicenter quality improvement evaluation was conducted in 28 Veterans Affairs facilities. We included visits for pharyngitis, rhinosinusitis, bronchitis, and upper respiratory tract infections (URI-NOS) that occurred during the 2015–2016 winter season. A manual record review identified complicated cases, which were excluded. Data were extracted for visits meeting criteria, followed by analysis of practice patterns, guideline congruence, and outcomes.

Of 5,740 visits, 4,305 met our inclusion criteria: pharyngitis (n = 558), rhinosinusitis (n = 715), bronchitis (n = 1,155), URI-NOS (n = 1,475), or mixed diagnoses (>1 ARI diagnosis) (n = 402). Antibiotics were prescribed in 68% of visits: pharyngitis (69%), rhinosinusitis (89%), bronchitis (86%), URI-NOS (37%), and mixed diagnosis (86%). Streptococcal diagnostic testing was performed in 33% of pharyngitis visits; group A Streptococcus was identified in 3% of visits. Streptococcal tests were ordered less frequently for patients who received antibiotics (28%) than those who did not receive antibiotics 44%; P < .01). Although 68% of visits for rhinosinusitis had documentation of symptoms, only 32% met diagnostic criteria for antibiotics. Overall, 39% of patients with uncomplicated ARIs received appropriate antibiotic management. The proportion of 30-day return visits for ARI care was similar for appropriate (11%) or inappropriate (10%) antibiotic management (P = .22).

Antibiotics were prescribed in most uncomplicated ARI visits, indicating substantial overuse. Practice was frequently discordant with guideline diagnostic and treatment recommendations.

Infections caused by multidrug-resistant gram-negative organisms (MDRGNOs) have been increasing every year. The objective of this study was to describe the prevalence of MDRGNOs and factors associated with MDRGNOs in patients with spinal cord injury or disorder (SCI/D).

Retrospective cohort study.

Department of Veterans Affairs (VA) electronic health record data from 142 VA facilities were evaluated for 19,642 patients with SCI/D. Multivariable cluster-adjusted models were fit to identify factors associated with MDRGNO.

Gram-negative (GN) cultures occurred in 44% of patients with SCI/D receiving care at VA facilities, and 11,527 (41.3%) GN cultures had an MDRGNO. The most frequent GN organisms (GNOs) were Escherichia coli (28.5%), Klebsiella pneumoniae (17.0%), and Pseudomonas aeruginosa (16.0%). Two-thirds of GN cultures were from the outpatient setting, where MDRGNO prevalence was 37.6%. Significant geographic variation in the prevalence of MDRGNOs was identified (South, 44.7%; Northeast, 44.3%; West, 36.8%; Midwest, 34.4%). Other factors associated with an MDRGNO were older age, injury characteristics, comorbidities, specimen type, healthcare setting, and healthcare exposure. Black (odds ratio [OR], 1.58; 95% confidence interval [CI], 1.39–1.78) and Hispanic race (OR, 1.58; 95% CI, 1.28–1.95), polymicrobial culture (OR, 2.67; 95% CI, 2.46–2.90), and antibiotic use in the previous 90 days (OR, 1.62; 95% CI, 1.50–1.76) were also associated with having an MDRGNO.

MDRGNOs were common in community and healthcare settings among veterans with SCI/D, with significant geographic variation. Health care and antibiotic exposures were significant factors associated with MDRGNOs. Priority should be given to controlling the spread of MDRGNOs in this special population, including a focus on judicious use of antibiotics.

Infect Control Hosp Epidemiol 2017;38:1464–1471

To examine variation in antibiotic coverage and detection of resistant pathogens in community-onset pneumonia.

Cross-sectional study.

A total of 128 hospitals in the Veterans Affairs health system.

Hospitalizations with a principal diagnosis of pneumonia from 2009 through 2010.

We examined proportions of hospitalizations with empiric antibiotic coverage for methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PAER) and with initial detection in blood or respiratory cultures. We compared lowest- versus highest-decile hospitals, and we estimated adjusted probabilities (AP) for patient- and hospital-level factors predicting coverage and detection using hierarchical regression modeling.

Among 38,473 hospitalizations, empiric coverage varied widely across hospitals (MRSA lowest vs highest, 8.2% vs 42.0%; PAER lowest vs highest, 13.9% vs 44.4%). Detection rates also varied (MRSA lowest vs highest, 0.5% vs 3.6%; PAER lowest vs highest, 0.6% vs 3.7%). Whereas coverage was greatest among patients with recent hospitalizations (AP for anti-MRSA, 54%; AP for anti-PAER, 59%) and long-term care (AP for anti-MRSA, 60%; AP for anti-PAER, 66%), detection was greatest in patients with a previous history of a positive culture (AP for MRSA, 7.9%; AP for PAER, 11.9%) and in hospitals with a high prevalence of the organism in pneumonia (AP for MRSA, 3.9%; AP for PAER, 3.2%). Low hospital complexity and rural setting were strong negative predictors of coverage but not of detection.

Hospitals demonstrated widespread variation in both coverage and detection of MRSA and PAER, but probability of coverage correlated poorly with probability of detection. Factors associated with empiric coverage (eg, healthcare exposure) were different from those associated with detection (eg, microbiology history). Providing microbiology data during empiric antibiotic decision making could better align coverage to risk for resistant pathogens and could promote more judicious use of broad-spectrum antibiotics.

Infect Control Hosp Epidemiol 2017;38:937–944

The purpose of this study was to quantify the effect of multidrug-resistant (MDR) gram-negative bacteria and methicillin-resistant Staphylococcus aureus (MRSA) healthcare-associated infections (HAIs) on mortality following infection, regardless of patient location.

We conducted a retrospective cohort study of patients with an inpatient admission in the US Department of Veterans Affairs (VA) system between October 1, 2007, and November 30, 2010. We constructed multivariate log-binomial regressions to assess the impact of a positive culture on mortality in the 30- and 90-day periods following the first positive culture, using a propensity-score–matched subsample.

Patients identified with positive cultures due to MDR Acinetobacter (n=218), MDR Pseudomonas aeruginosa (n=1,026), and MDR Enterobacteriaceae (n=3,498) were propensity-score matched to 14,591 patients without positive cultures due to these organisms. In addition, 3,471 patients with positive cultures due to MRSA were propensity-score matched to 12,499 patients without positive MRSA cultures. Multidrug-resistant gram-negative bacteria were associated with a significantly elevated risk of mortality both for invasive (RR, 2.32; 95% CI, 1.85–2.92) and noninvasive cultures (RR, 1.33; 95% CI, 1.22–1.44) during the 30-day period. Similarly, patients with MRSA HAIs (RR, 2.77; 95% CI, 2.39–3.21) and colonizations (RR, 1.32; 95% CI, 1.22–1.50) had an increased risk of death at 30 days.

We found that HAIs due to gram-negative bacteria and MRSA conferred significantly elevated 30- and 90-day risks of mortality. This finding held true both for invasive cultures, which are likely to be true infections, and noninvasive infections, which are possibly colonizations.

Infect Control Hosp Epidemiol 2017;38:848–856

To detail the activities of the Veterans Health Administration (VHA) Antimicrobial Stewardship Initiative and evaluate outcomes of the program.

Observational analysis.

The VHA is a large integrated healthcare system serving approximately 6 million individuals annually at more than 140 medical facilities.

Utilization of nationally developed resources, proportional distribution of antibiotics, changes in stewardship practices and patient safety measures were reported. In addition, inpatient antimicrobial use was evaluated before and after implementation of national stewardship activities.

Nationally developed stewardship resources were well utilized, and many stewardship practices significantly increased, including development of written stewardship policies at 92% of facilities by 2015 (P<.05). While the proportional distribution of antibiotics did not change, inpatient antibiotic use significantly decreased after VHA Antimicrobial Stewardship Initiative activities began (P<.0001). A 12% decrease in antibiotic use was noted overall. The VHA has also noted significantly declining use of antimicrobials prescribed for resistant Gram-negative organisms, including carbapenems, as well as declining hospital readmission and mortality rates. Concurrently, the VHA reported decreasing rates of Clostridium difficile infection.

The VHA National Antimicrobial Stewardship Initiative includes continuing education, disease-specific guidelines, and development of example policies in addition to other highly utilized resources. While no specific ideal level of antimicrobial utilization has been established, the VHA has shown that improving antimicrobial usage in a large healthcare system may be achieved through national guidance and resources with local implementation of antimicrobial stewardship programs.

Infect Control Hosp Epidemiol 2017;38:513–520

To describe the burden of extended-spectrum β-lactamase (ESBL) Enterobacteriaceae in veterans with spinal cord injury or disorder (SCI/D), to identify risk factors for ESBL acquisition, and to assess impact on clinical outcomes

Retrospective case-case-control study

Veterans with SCI/D and utilization at a Veterans’ Affairs medical center from January 1, 2012, to December 31, 2013.

Patients with a positive culture for ESBL Klebsiella pneumoniae, Escherichia coli, or Proteus mirabilis were matched with patients with non-ESBL organisms by organism, facility, and level of care and to uninfected controls by facility and level of care. Inpatients were also matched by time at risk. Univariate and multivariate matched models were assessed for differences in risk factors and outcomes.

A total of 492 cases (62.6% outpatients) were matched 1:1 with each comparison group. Recent prior use of fluoroquinolones and prior use of third- and fourth-generation cephalosporins were independently associated with ESBL compared to the non-ESBL group (adjusted odds ratio [aOR], 2.61; 95% confidence interval [CI], 1.77–3.84; P<.001 for fluoroquinolones and aOR, 3.86; 95% CI, 2.06–7.25; P<.001 for third- and fourth-generation cephalosporins) and the control group (aOR, 2.10; 95% CI, 1.29–3.43; P = .003 for fluoroquinolones; and aOR, 3.31; 95% CI, 1.56–7.06; P=.002 for third- and fourth-generation cephalosporins). Although there were no differences in mortality rate, the ESBL group had a longer post-culture length of stay (LOS) than the non-ESBL group (incidence rate ratio, 1.36; 95% CI, 1.13–1.63; P=.001).

All SCI/D patients with ESBL were more likely to have had recent exposure to fluoroquinolones or third- and fourth-generation cephalosporins, and hospitalized patients were more likely to have increased post-culture LOS. Programs targeted toward reduced antibiotic use in SCI/D patients may prevent subsequent ESBL acquisition.

Infect Control Hosp Epidemiol 2016;37:768–776

To estimate avoidable intravenous (IV) fluoroquinolone use in Veterans Affairs (VA) hospitals.

A retrospective analysis of bar code medication administration (BCMA) data.

Acute care wards of 128 VA hospitals throughout the United States.

Data were analyzed for all medications administered on acute care wards between January 1, 2006, and December 31, 2010. Patient-days receiving therapy were expressed as fluoroquinolone-days (FD) and divided into intravenous (IV; all doses administered intravenously) and oral (PO; at least one dose administered per os) FD. We assumed IV fluoroquinolone use to be potentially avoidable on a given IV FD when there was at least 1 other medication administered via the enteral route.

Over the entire study period, 884,740 IV and 830,572 PO FD were administered. Overall, avoidable IV fluoroquinolone use accounted for 46.8% of all FD and 90.9% of IV FD. Excluding the first 2 days of all IV fluoroquinolone courses and limiting the analysis to the non-ICU setting yielded more conservative estimates of avoidable IV use: 20.9% of all FD and 45.9% of IV FD. Avoidable IV use was more common for levofloxacin and more frequent in the ICU setting. There was a moderate correlation between avoidable IV FD and total systemic antibiotic use (r = 0.32).

Unnecessary IV fluoroquinolone use seems to be common in the VA system, but important variations exist between facilities. Antibiotic stewardship programs could focus on this patient safety issue as a “low-hanging fruit” to increase awareness of appropriate antibiotic use.