Leveraging stewardship to promote ceftriaxone use in severe infections with low- and no-risk AmpC Enterobacterales.

AmpC ß-lactamases are associated with development of ceftriaxone resistance despite initial in vitro susceptibility, but the risk of AmpC derepression is not equal among Enterobacterales. The purpose of this study was to evaluate the impact of an AmpC stewardship intervention on the definitive treatment of low- and no-risk Enterobacterales. This was an IRB-approved, single pre-test, post-test quasi-experiment at a 5-hospital system. An AmpC stewardship intervention was implemented in July 2022 and included prescriber education, the removal of microbiology comments indicating potential for ceftriaxone resistance on therapy, and the modification of a blood PCR comment for Serratia marcescens to recommend ceftriaxone. Adults ≥18 years pre-intervention (July 2021 to December 2021) and post-intervention (July 2022 to December 2022) who received ≥72 hours of inpatient definitive therapy and had non-urine cultures growing low- and no-risk organisms (S. marcescens, Providencia spp., Citrobacter koseri, Citrobacter amalonaticus, or Morganella morganii) were included. The primary endpoint was definitive treatment with ceftriaxone. A total of 224 patients were included; 115 (51%) in pre-intervention and 109 (49%) in post-intervention. Definitive ceftriaxone therapy was prescribed more frequently after intervention [6 (5%) vs 72 (66%), P < 0.001]. After adjustment for critical illness, patients in the post-group were more likely to receive definitive ceftriaxone (adjOR, 34.7; 95% CI, 13.9-86.6). The proportion of patients requiring retreatment was 18 (15%) and 11 (10%) for pre- and post-intervention patients (P = 0.22), and ceftriaxone resistance within 30 days occurred in 5 (4%) and 2 (2%) patients in the pre- and post-group (P = 0.45). An antimicrobial stewardship intervention was associated with increased ceftriaxone prescribing and similar patient outcomes for low- and no-risk AmpC Enterobacterales.

Performance of the Reveal Rapid Antibiotic Susceptibility Testing System on Gram-Negative Blood Cultures at a Large Urban Hospital.

Timely and effective antibiotic treatment is vital for sepsis, with increasing incidence of antimicrobial-resistant bacteremia driving interest in rapid phenotypic susceptibility testing. To enable the widespread adoption needed to make an impact, antibiotic susceptibility testing (AST) systems need to be accurate, enable rapid intervention, have a broad antimicrobial menu and be easy to use and affordable. We evaluated the Specific Reveal (Specific Diagnostics, San Jose, CA) rapid AST system on positive blood cultures with Gram-negative organisms in a relatively resistant population in a large urban hospital to assess its potential for routine clinical use. One hundred four randomly selected positive blood cultures (Virtuo; bioMérieux) were Gram stained, diluted 1:1,000 in Pluronic water, inoculated into 96-well antibiotic plates, sealed with the Reveal sensor panel, and placed in the Reveal instrument for incubation and reading. The MIC and susceptible/intermediate/resistant category was determined and compared to results from Vitek 2 (bioMérieux) for the 17 antimicrobials available and to Sensititre (Thermo Fisher) for 24 antimicrobials. Performance was also assessed with contrived blood cultures with 33 highly resistant strains. Reveal was in 98.0% essential agreement (EA) and 96.3% categorical agreement (CA) with Sensititre, with just 1.3% very major error (VME) and 97.0%/96.2%/1.3% EA/CA/VME versus Vitek 2. Reveal results for contrived highly resistant strains were equivalent, with EA/CA/VME of 97.7%/95.2%/1.0% with CDC/FDA Antibiotic Resistance Isolate Bank references. Average time to result (TTR) for Reveal was 4.6 h. Sample preparation was relatively low skill and averaged 3 min. We conclude that the Reveal system enables accurate and rapid susceptibility testing of Gram-negative blood cultures.

Performance of Ceftolozane-Tazobactam Etest, MIC Test Strips, and Disk Diffusion Compared to Reference Broth Microdilution for ß-Lactam-Resistant Pseudomonas aeruginosa Isolates.

The performance characteristics of the ceftolozane-tazobactam (C-T) Etest (bioMérieux, Marcy l'Etoile, France), MIC test strips (MTS; Liofilchem, Italy), and disk diffusion (Hardy, Santa Ana, CA) were evaluated for a collection of 308 beta-lactam-resistant isolates of Pseudomonas aeruginosa recovered from three institutions in Los Angeles, CA. Reference testing was performed by the reference broth microdilution (rBMD) method. MIC and disk results were interpreted using Clinical and Laboratory Standards Institute breakpoints. Overall, 72.5% of the isolates were susceptible to C-T by rBMD. Etest and disk diffusion demonstrated acceptable performance, whereas MTS yielded a greater than acceptable percentage of minor errors. Categorical agreement was 96.8% for Etest, 87.0% for MTS, and 92.9% for disk diffusion. No very major errors were observed by any test, and no major errors (ME) were observed by Etest or disk diffusion. Two ME (0.9% of susceptible isolates) were observed by MTS. The incidence of minor errors was 3.2%, 12.3%, and 7.1% for Etest, MTS, and disk diffusion, respectively. Essential agreement (EA) for Etest was excellent, at 97.7%, whereas the MICs obtained by MTS tended to be 1 to 2 dilutions higher than those obtained by rBMD, with an EA of 87.0%.

Stewardship opportunities in viral pneumonia: Why not the immunocompromised?

Antimicrobial management of viral pneumonia has proven to be a challenge in hospitalized immunocompromised patients. A host of factors contribute to the dilemma, such as diagnostic uncertainty, lack of organism identification, and clinical status of the patient. Respiratory virus panel (RVP) use was compared between 131 immunocompromised patients who received send-out (n = 56) vs in-house (n = 75) testing. Antimicrobial optimization interventions consisted of antiviral addition/discontinuation, antibiotic discontinuation/de-escalation, or modification of immunosuppressive regimen. After implementation of an in-house test with audit and feedback, turnaround time of the RVP was reduced from 46.7 to 5.5 hours (P < .001) and time to intervention was reduced from 52.1 to 13.9 hours (P < .001), yet the frequency of antimicrobial optimization interventions was unchanged (30.7% vs 35.7%). Differences were not observed in duration of empiric antibiotic therapy or length of stay. The overall discontinuation rate for patients tested with a RVP was low (4.6%), and those with positive RVP (n = 43) had antibiotics stopped in 14% of cases. Bacterial pneumonia coinfection was confirmed in 2 patients. Further systematic efforts should be taken to reduce antibiotic use in viral pneumonia and identify the major barriers in the immunocompromised population.

Ceftriaxone versus cefepime or carbapenems for definitive treatment of low-risk AmpC-Harboring Enterobacterales bloodstream infections in hospitalized adults: A retrospective cohort study.

OBJECTIVE: To compare outcomes of ceftriaxone to AmpC-stable therapies in patients with bacteremia caused by low-risk AmpC harboring Enterobacterales. METHODS: IRB-approved, retrospective cohort of hospitalized patients ≥18 years old with Serratia marcescens, Morganella morganii, or Providencia spp. bacteremia from 1/1/2017-2/28/2024. Patients were compared by definitive therapy with ceftriaxone vs AmpC-stable therapy (cefepime, carbapenem). The primary endpoint was 30-day all-cause mortality; secondary endpoints were clinical failure and development of ceftriaxone resistance. RESULTS: 163 patients were included; 33.1 % received ceftriaxone, 66.9 % AmpC-stable therapies. 30-day all-cause mortality was 9.3 % ceftriaxone vs 10.1 % AmpC stable patients (P = 0.87); ceftriaxone definitive therapy was not associated with 30-day all-cause mortality (adjOR, 0.79; 95 %CI, 0.23-2.3). There were no differences in clinical failure (9.3 % vs 21.1 %, P = 0.059) or relapsing infection (5.6 % vs 9.3 %, P = 0.55) between ceftriaxone and AmpC-stable treated patients. CONCLUSIONS: Patients treated with definitive ceftriaxone for low-risk AmpC Enterobacterales bacteremia had similar outcomes to AmpC stable therapies.

Use of whole genomic sequencing to detect New Delhi metallo-B-lactamase (NDM)-producing Escherichia coli outbreak associated with endoscopic procedures.

BACKGROUND: Whole-genome sequencing (WGS) has emerged as an alternative genotyping tool for outbreak investigations in the healthcare setting. We describe the investigation and control of a New Delhi metallo-B-lactamase (NDM)-producing Escherichia coli cluster in Southeast Michigan. METHODS: Michigan Bureau of Laboratories identified several closely related NDM-producing E. coli isolates with WGS. An epidemiologic investigation, including case-control study, assessment of infection control practices, and endoscope culturing, was performed to identify source of transmission. Targeted screening of potentially exposed patients was performed following identification of probable source. RESULTS: Between July 2021 and February 2023, nine patients were identified. Phylogenetic analysis confirmed the isolates were closely related with less than 26 single nucleotide polymorphism (SNP) differences between isolates, suggesting an epidemiological link. Eight (89%) patients had a duodenoscope and/or gastroscope exposure. Cases were compared with 23 controls. Cases had significantly higher odds of exposure to duodenoscopes (odds ratio 15.0; 95% CI, 1.8-142.2; P = .015). The mean incubation period, estimated as date of procedure to positive index culture, was 86 days (range, 1-320 days). No lapses in endoscope reprocessing were identified; NDM-producing E. coli was not recovered from reprocessed endoscopes or during targeted screening. No additional cases were identified after removal of implicated gastroscopes and replacement of duodenoscope with disposable end caps. CONCLUSIONS: In this investigation, WGS was utilized to identify transmission of an NDM-producing E. coli outbreak associated with endoscope exposure. Coupled with epidemiologic data, WGS can facilitate outbreak investigations by rapidly identifying linked cases and potential sources to prevent further transmission.

Evaluation of a microarray-based assay for rapid identification of Gram-positive organisms and resistance markers in positive blood cultures.

Rapid identification of pathogens directly from positive blood cultures can play a major role in reducing patient mortality rates. We evaluated the performance of the Verigene Gram-Positive Blood Culture (BC-GP) assay (Nanosphere Inc., Northbrook, IL) for detection of commonly isolated Gram-positive organisms as well as associated resistance markers from positive blood cultures. Positive blood cultures (VersaTREK; Trek Diagnostic Systems, Independence, OH) from 203 patients with Gram-positive organism infections were analyzed using the BC-GP assay within 12 h for the detection of 12 different organisms, including staphylococci, streptococci, and enterococci, as well as for the presence of 3 resistance markers (mecA, vanA, and vanB). Results were compared to those of routine laboratory methods for identification and susceptibility testing. For identification of organisms and detection of resistance markers in 178 monomicrobial positive blood cultures, the BC-GP assay showed 94% and 97% concordance, respectively, with routine methods. After 25 polymicrobial cultures were included, the results showed 92% and 96% agreement for identification and resistance markers, respectively, for a total of 203 positive cultures. In 6/25 polymicrobial cultures, at least 1 isolate was not detected. Concordance levels for detection of major pathogens such Staphylococcus aureus (n = 45) and enterococci (n = 19) were 98% and 95%, respectively. Agreement levels for detection of resistance markers such as mecA and vanA/B were 92% and 100%, respectively. The BC-GP assay is capable of providing rapid identification of Gram-positive cocci as well as detection of resistance markers directly from positive blood cultures at least 24 to 48 h earlier than conventional methods.

Respiratory culture nudge improves antibiotic prescribing for Moraxella catarrhalis and Haemophilus influenzae lower respiratory tract infections.

We compared optimal antibiotic prescribing before and after implementing an interpretive ß-lactamase microbiology comment for Haemophilus influenzae and Moraxella catarrhalis in lower respiratory-tract infections. The postintervention group was associated with 5-fold increased odds of optimal de-escalation (adjusted odds ratio, 5.03; 95% confidence interval, 2.57-9.87).

A Microbiological Assay of Common Operating Room (OR) Tapes: Developing a Culture for Patient Safety.

BACKGROUND: There are no existing practices or methods to ensure cleanliness, sterility, or prevent cross-contamination when it comes to common operating room (OR) tape. The authors hypothesized that adhesive tapes used by anesthesia providers in ORs and off-site surgical areas might be colonized by microorganisms and that culturing these tape rolls would reveal significant monomicrobial and polymicrobial contamination.  Material and Methods: The primary objective of this observational cohort study was to report and compare contamination rate including polymicrobial contamination rate between tape specimens collected from storage site and specimen from the ORs, off-sites, and after use on a patient. The outcome measures were the culture reports of the adhesive tapes. The authors then designed an intervention that integrated anesthesia providers' hand hygiene and maintenance of a barrier between the OR tapes and OR surfaces. RESULTS: The authors reported gross contamination and cross-contamination among the OR off-site tapes. The contamination rates reported for tapes from OR, off-site specimens, and patient specimens were 68.2%,63.2%, and 100%, respectively. The authors again cultured adhesive tapes after the intervention and reported improved outcomes. CONCLUSIONS: The current quality improvement (QI) project identified the potential for OR tapes to serve as microbial vectors. The authors advocate environmental decontamination and anesthesia providers' hand hygiene in parallel as a part of routine anesthesia care in their practice and agree that the endotracheal tubes (ETTs) and orogastric or nasogastric tubes should be pre-packaged with single-use tape, which can be used for securing devices.

The long-term sustainability of a respiratory culture nudge.

Resource-intensive interventions and education are susceptible to a lack of long-term sustainability and regression to the mean. The respiratory culture nudge changed reporting to "Commensal Respiratory Flora only: No S. aureus/MRSA or P. aeruginosa." This study demonstrated sustained reduction in broad-spectrum antibiotic duration and long-term sustainability 3 years after implementation.

Risk Factors Associated With Hospitalization and Death in COVID-19 Breakthrough Infections.

Background: Characterizations of coronavirus disease 2019 (COVID-19) vaccine breakthrough infections are limited. We aim to characterize breakthrough infections and identify risk factors associated with outcomes. Methods: This was a retrospective case series of consecutive fully vaccinated patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a multicenter academic center in Southeast Michigan, between December 30, 2020, and September 15, 2021. Results: A total of 982 patients were identified; the mean age was 57.9 years, 565 (59%) were female, 774 (79%) were White, and 255 (26%) were health care workers (HCWs). The median number of comorbidities was 2; 225 (23%) were immunocompromised. BNT162b2 was administered to 737 (75%) individuals. The mean time to SARS-CoV-2 detection was 135 days. The majority were asymptomatic or exhibited mild to moderate disease, 154 (16%) required hospitalization, 127 (13%) had severe-critical illness, and 19 (2%) died. Age (odds ratio [OR], 1.14; 95% CI, 1.04-1.07; P < .001), cardiovascular disease (OR, 3.02; 95% CI, 1.55-5.89; P = .001), and immunocompromised status (OR, 2.57; 95% CI, 1.70-3.90; P < .001) were independent risk factors for hospitalization. Additionally, age (OR, 1.06; 95% CI, 1.02-1.11; P = .006) was significantly associated with mortality. HCWs (OR, 0.15; 95% CI, 0.05-0.50; P = .002) were less likely to be hospitalized, and prior receipt of BNT162b2 was associated with lower odds of hospitalization (OR, 0.436; 95% CI, 0.303-0.626; P < .001) and/or death (OR, 0.360; 95% CI, 0.145-0.898; P = .029). Conclusions: COVID-19 vaccines remain effective at attenuating disease severity. However, patients with breakthrough infections necessitating hospitalization may benefit from early treatment modalities and COVID-19-mitigating strategies, especially in areas with substantial or high transmission rates.

Comparison of bacterial maxillary sinus cultures between odontogenic sinusitis and chronic rhinosinusitis.

BACKGROUND: Bacterial odontogenic sinusitis (ODS) is distinct from other forms of rhinosinusitis. Diagnosing ODS can be challenging because of nonspecific clinical presentations and underrepresentation in the literature. The purpose of this study was to compare maxillary sinus bacterial cultures between patients with ODS and chronic rhinosinusitis (CRS), to determine whether certain bacteria are associated with ODS. METHODS: This was a retrospective case-control study of 276 consecutive patients from August 2015 to August 2019 who underwent endoscopic sinus surgery (ESS) for bacterial ODS, CRS without nasal polyps (CRSsNP), or CRS with nasal polyps (CRSwNP). When present, pus was sterilely cultured from maxillary sinuses after maxillary antrostomy, and aerobic and anaerobic cultures were immediately sent for processing. Demographics and culture results were compared between ODS and CRS patients, and then separately between ODS and CRSsNP, and ODS and CRSwNP. ODS culture results were also compared between different dental pathologies (endodontic vs oroantral fistula). RESULTS: The following bacteria were significantly more likely in ODS compared to CRS: mixed anaerobes, Fusobacterium spp., Eikenella corrodens, Streptococcus intermedius, Streptococcus anginosus, and Streptococcus constellatus. Staphylococcus aureus and Pseudomonas aeruginosa were inversely related to ODS. There were no significant differences in cultures between the different dental pathologies. CONCLUSION: Certain bacteria were more likely to be associated with ODS compared to CRS when purulence was cultured from the maxillary sinus. Physicians should evaluate for an odontogenic source of sinusitis when these ODS-associated bacteria are identified in maxillary sinus cultures.