bluuebunny/crossref_metadata_2025 huggingface dataset:
P-1470. Single-dose Aminoglycosides versus Carbapenems for the Treatment of Uncomplicated Urinary Tract Infections caused by Extended-spectrum Beta-lactamase-phenotype Enterobacterales
Authors: DeFrank Anna , Bosco Michael , Zafonte Veronica B , Islam Shahidul , Johnson Diane
Published: January 2025

Background

Carbapenems are often used for treatment of infections caused by extended-spectrum β-lactamase-producing (ESBL) Enterobacterales. Over utilization has led to carbapenem resistance and these infections can be difficult to treat. Limiting unnecessary carbapenem exposure has been shown to decrease the risk of carbapenem resistance and a 2023 Infectious Disease Society of America guidance document recommends non-carbapenem alternatives for the treatment of uncomplicated urinary tract infections (uUTI). A single dose of an aminoglycoside (AG) can be considered, however clinical trial data is lacking, especially for those with infections caused by drug-resistant pathogens.

Methods

A retrospective, multi-center, cohort study over 60-months evaluated hospitalized patients within the NYU Langone Health System ≥18 years of age who received a single dose of an AG for the treatment of an uUTI caused by an AG-susceptible, ESBL-phenotype (defined as ceftriaxone MIC ≥2 mcg/mL) gram-negative bacilli (GNB). Patients who received MEM for ≥72 hours were the active comparator. Clinical success, a composite of the following, was assessed at Day 7 (±2 days) post-therapy or at discharge, whichever occurred sooner: clinical cure, defined as complete resolution or significant improvement of baseline uUTI signs/symptoms; microbiological response, defined as reduction in baseline uropathogen to < 103 CFU/mL. To demonstrate non-inferiority, 352 patients were needed to achieve 90% power.

Results

Baseline characteristics can be found in Table 1. Clinical success occurred in 97% (N=37) vs. 86% (N=129) of patients treated with an AG vs. MEM, respectively (p=0.052). Non-inferiority was met with a 0.11 proportion difference in clinical success (90% confidence interval [-0.011, 0.25]) within the predefined non-inferiority limit. No statistically significant differences in secondary outcomes were observed (Table 2). Diarrhea was more common in those treated with MEM (p=0.049; Table 3).

Conclusion

Single dose AG demonstrated comparable clinical success and recurrence rates to MEM for the treatment of uUTI caused by ESBL-producing GNB. The study was underpowered, increasing the chance for type II error. A future prospective study is warranted to justify preliminary findings.

Disclosures

Michael Bosco, PharmD, BCIDP, AAHIVP, Shionogi Inc: Advisor/Consultant|Shionogi Inc: Grant/Research Support
P-1493. In Vitro Activity of Clindamycin in Comparison with Linezolid Versus Streptococcus pyogenes Clinical Isolates Recovered from Patients in Manitoba, Canada
Authors: Li Jeremy , Lagace-Wiens Philippe , Adam Heather , Pieroni Peter , Zhanel George , Karlowsky James , Walkty Andrew
Published: January 2025

Background

Clindamycin is often used in combination with a beta-lactam antimicrobial for the treatment of serious infections caused by Streptococcus pyogenes (e.g., necrotizing fasciitis, streptococcal toxic shock syndrome) due to its ability to suppress bacterial toxin synthesis. Of concern, increasing clindamycin resistance among S. pyogenes isolates has been reported in many parts of the world. The purpose of this study was to compare the in vitro activity of clindamycin with linezolid versus a contemporary Canadian collection of S. pyogenes clinical isolates.

Methods

S. pyogenes isolates from wounds and sterile body sites (one per patient) were obtained from three microbiology laboratories in Manitoba, Canada between December, 2022 and November, 2023. Susceptibility testing was performed by broth microdilution as described by CLSI, with MICs interpreted using current CLSI breakpoints. A D-test was set up for each isolate to investigate whether inducible clindamycin resistance was present.

Results

Susceptibility testing was performed on 140 S. pyogenes clinical isolates. The isolates were obtained from wound swabs (n = 71, 50.7%), sterile fluid/tissue samples (n = 27, 19.3%), and blood cultures (n = 42, 30.0%). All isolates were fully susceptible in vitro to penicillin and vancomycin. The proportion of isolates testing susceptible to clindamycin and linezolid was 82.9% and 100%, respectively. All of the clindamycin-resistant isolates demonstrated an inducible resistance phenotype (clindamycin MIC ≤0.12 ug/mL in all cases). Clindamycin susceptibility was similar for isolates from wound swabs (81.7%) and isolates from blood/sterile sites (84.1%).

Conclusion

The proportion of S. pyogenes isolates testing susceptible to clindamycin was 82.9%. All clindamycin resistant isolates demonstrated an inducible resistance phenotype. Further data are required to determine whether inducible clindamycin resistance is clinically relevant when clindamycin is used as adjunctive therapy (in combination with a beta-lactam) for serious S. pyogenes infections. All isolates tested remained susceptible to linezolid.

Disclosures

All Authors: No reported disclosures
P-1514. Cefepime-taniborbactam Exhibits Limited Cross-resistance with Ceftazidime-avibactam and Ceftolozane-tazobactam against Carbapenem-nonsusceptible Enterobacterales and Multidrug-resistant Pseudomonas aeruginosa from the United States 2018-2022
Authors: Hackel Meredith , Wise Mark G , Moeck Greg , Sahm Daniel F
Published: January 2025

Background

Cefepime-taniborbactam (FTB) is an investigational β-lactam/β-lactamase inhibitor combination with activity against most isolates of carbapenem-resistant and multidrug-resistant (MDR) Enterobacterales and P. aeruginosa. We evaluated the activity of FTB and comparators against clinical isolates of Enterobacterales and P. aeruginosa from the US and assessed FTB cross-resistance to ceftazidime-avibactam (CZA) and ceftolozane-tazobactam (CT) in resistant subsets.

Methods

MICs were determined by CLSI reference broth microdilution against Enterobacterales (n=4,932) and P. aeruginosa (n=1,508) collected in the US in 2018-2022. Phenotypes were based on 2024 CLSI breakpoints. A provisional FTB susceptible breakpoint of ≤16 µg/mL was used for comparative purposes. An MDR phenotype was defined as resistance to ≥1 agent from ≥3 drug classes.

Results

Among Enterobacterales, 1.8% of isolates were nonsusceptible to meropenem (MEM; Table 1). FTB was the most active agent, inhibiting 96.7% of MEM-nonsusceptible Enterobacterales isolates at ≤16 µg/mL whereas 80.4% were susceptible to CZA and 87.0% were susceptible to meropenem-vaborbactam (MEV). Among P. aeruginosa, 11.9% of isolates were MDR (Table 1). FTB was the most active agent, inhibiting 82.2% of MDR P. aeruginosa isolates at ≤16 µg/mL whereas 56.1% were susceptible to CT and 63.9% were susceptible to CZA (Table 1). Among MEM-nonsusceptible Enterobacterales, 80.2% were susceptible to both FTB and CZA, 16.5% were susceptible to FTB but not to CZA, 1.1% were susceptible to CZA but not to FTB, and 2.2% were nonsusceptible to both agents (Table 2A). Among MDR P. aeruginosa, 54.4% were susceptible to both FTB and CT, 27.8% were susceptible to FTB but not to CT, 1.7% were susceptible to CT but not to FTB, and 16.1% were nonsusceptible to both agents (Table 2B).

Conclusion

FTB was active in vitro against recent clinical isolates of Enterobacterales and P. aeruginosa from the US including most isolates resistant to CZA and CT in key resistant subsets. These data support continued development of FTB as a potential treatment option for patients with challenging infections due to carbapenem-resistant Enterobacterales and MDR P. aeruginosa.

Disclosures

Greg Moeck, PhD, Biomedical Advanced Research and Development Authority (BARDA): Grant/Research Support|Venatorx Pharmaceuticals, Inc.: Grant/Research Support|Venatorx Pharmaceuticals, Inc.: Stocks/Bonds (Private Company) Daniel F. Sahm, PhD, Pfizer, Inc.: Advisor/Consultant
P-1520. Addition of Relebactam Increases Susceptibility to Imipenem Among Imipenem-Intermediate Pseudomonas aeruginosa: Asia/Pacific SMART 2018-2022
Authors: Wise Mark G , Andrew DeRyke C , Chen Wei-Ting , Siddiqui Fakhar , Young Katherine , Motyl Mary , Sahm Daniel F
Published: January 2025

Background

Imipenem/relebactam (IMR) combines imipenem with the β-lactamase inhibitor relebactam, an inhibitor of class A and C β-lactamases. We assessed the activity of IMR and comparators against Pseudomonas aeruginosa collected in 9 countries in the Asia/Pacific region as part of the global SMART surveillance program, with a focus on the increased antimicrobial activity brought by the addition of relebactam to imipenem for those organisms interpreted as “intermediate” by 2024 CLSI criteria (MIC = 4 µg/mL) to imipenem alone.

Methods

From 2018-2022, 50 clinical laboratories in nine countries in Asia/Pacific (Australia, Hong Kong, Malaysia, New Zealand, Philippines, South Korea, Taiwan, Thailand, and Vietnam) each collected up to 250 consecutive, aerobic or facultative, Gram-negative pathogens per year from patients with bloodstream, intraabdominal, lower respiratory tract, and urinary tract infections. MICs were determined using CLSI broth microdilution and interpreted with 2024 CLSI breakpoints. Most isolates that were imipenem or ceftolozane/tazobactam-nonsusceptible (NS) were screened for β-lactamases.

Results

IMR demonstrated excellent antimicrobial activity against isolates from most countries, inhibiting >80% of the isolates from each country except Vietnam (63.2% susceptible; Table). Ceftolozane/tazobactam and amikacin showed similar levels of activity. Limiting the analysis to isolates that tested “intermediate” to imipenem (MIC = 4 µg/mL) revealed that the addition of relebactam rendered >96% of the organisms from each country susceptible, ranging from 100% (Australia, New Zealand and South Korea) to 96.3% (Vietnam). Most imipenem-I P. aeruginosa examined molecularly (727/740; 98.2%) did not carry an acquired β-lactamase. As relebactam itself does not possess antibacterial activity, this suggests that the increased antimicrobial activity attributable to its addition is likely a result of its inhibitory activity on the intrinsic AmpC (blaPDC) in this species.

Conclusion

IMR showed potent activity against clinical P. aeruginosa collected in Asia/Pacific. The addition of relebactam to imipenem was responsible for the inhibition of >96% of isolates that were “intermediate” to imipenem alone.

Disclosures

Daniel F. Sahm, PhD, Pfizer, Inc.: Advisor/Consultant
P-1526. In vitro Activity of Ceftobiprole Against Prominent Methicillin-resistant Staphylococcus aureus Clonal Groups Collected Through the SENTRY Antimicrobial Surveillance Program
Authors: Mendes Rodrigo E , Kimbrough Hank , Maher Joshua , Smart Jennifer , Jones Mark E , Castanheira Mariana , Sader Helio S
Published: January 2025

Background

Ceftobiprole (BPR), an advanced generation cephalosporin, was recently (April 2024) approved by the US FDA for treating Staphylococcus aureus bacteremia (SAB), community-acquired bacterial pneumonia (CABP), and acute bacterial skin and skin structure infections (ABSSSI). This study examined the activity of BPR and the comparator agent ceftaroline (CPT) against a contemporary (2018-2019) collection of methicillin-resistant S. aureus (MRSA) isolates from major pandemic lineages.

Genomic features and susceptibility profile of MRSA isolates stratified by clonal group and subgroups.

Methods

150 MRSA collected from 38 hospitals in 18 countries were susceptibility (S) tested against BPR and CPT using CLSI broth microdilution methods; FDA breakpoints were applied. Total genomic DNA was extracted and sequenced. Assembled genomes were used to determine multi-locus sequence type (ST), clonal complex (CC), spa (not shown) and SCCmec types; results of typing methods were used to assign clonal group (CG).

Results

Twenty-four CGs, including subdivisions, were identified; 3 isolates could not be assigned a CG. Prominent CGs were USA300 (n=53, 35.3%), UK-EMRSA-15 (n=33, 22.0%), USA100 (n=28, 18.7%), and USA800 (n=15, 10.0%); rare CGs (≤ 3 isolates; n=21) totaled 14.0% (TABLE). Against all MRSA, 97.3% were BPR-S and 85.3% were CPT-S. BPR was more active than CPT across CGs and subdivisons: USA300, 100.0% BPR-S/94.3% CPT-S; UK-EMRSA-15, 93.9% BPR-S/69.7% CPT-S; USA100, 96.4% BPR-S/75.0% CPT-S; USA800, 100.0% BPR-S/CPT-S. Against rare or unknown CGs, 95.2% were BPR-S and 90.5% were CPT-S. Four (2.7%) and 22 (14.7%) isolates were BPR- and CPT-NS, respectively; all BPR-NS isolates were CPT-NS whereas 81.8% of CPT-NS isolates were BPR-S. No CG feature united BPR-NS isolates (n=2 UK-EMRSA-15, CC22/ST22/SCCmec-IV(2B); USA100-Swiss, CC5/ST105/SCCmec-II(2A); Hungarian-Brazilian; CC8/ST239/SCCmec-III(3A)), whereas 19/22 (86.4%) CPT-NS isolates were from subgroups of UK-EMRSA-15, USA100, or Hungarian-Brazilian CGs.

Conclusion

This study reports the potent activity of BPR against a global collection of MRSA from prominent pandemic lineages. The low frequency of BPR-NS isolates, particularly among highly represented CGs including UK-EMRSA and USA100, and its activity against CPT-NS isolates, support the use of BPR in the treatment of MRSA-associated SAB, ABSSSI, and CABP.

Disclosures

Rodrigo E. Mendes, PhD, GSK: Grant/Research Support Jennifer Smart, PhD, Basilea Pharmaceutica International Ltd: Employee|Basilea Pharmaceutica International Ltd: Stocks/Bonds (Public Company) Mark E. Jones, PhD, Basilea Pharmaceutica International Ltd: Employee|Basilea Pharmaceutica International Ltd: Stocks/Bonds (Public Company)
P-1565. Antimicrobial Resistance among Gram-negative Urinary Isolates from Kidney Transplant Recipients: Implications for Precision Antimicrobial Stewardship
Authors: London Abby , Farmakiotis Dimitrios , Vieira Kendra M , Rogers Ralph , Shi Yiyun
Published: January 2025

Background

Urinary tract infections (UTI) in kidney transplant recipients (KTR) can lead to chronic allograft dysfunction, progression to sepsis, graft loss, and death. With such morbidity and even mortality, it is important to determine if this population has similar antimicrobial resistance (AMR) patterns to those of the general patient population in the same community, to determine the need for dedicated antibiograms, formulate empiric protocols for treatment, and optimize antimicrobial stewardship (AMS) interventions.

Methods

We captured positive urine cultures between 1/1/09 and 11/4/19 in KTR at Brown-University affiliated hospitals. We compared resistance rates to preferred oral antibiotics for the management of UTI and for ceftriaxone (CTX, marker of extended-spectrum beta-lactamase production) to those reported in our institutional antibiogram. The study was approved by the Lifespan Institutional Review Board.

Results

We studied 236 isolates from 294 KTR. 122 (42%) were females; 57 (19%) were Black. Median age at transplant was 55 (range: 10-82) years old. The most common causes of end-stage renal disease included hypertension (n=93, 32%) and diabetes (n=55, 19%). Of 187 Gram-negative organisms isolated, the most common were E. coli (n=112), K. pneumoniae (n=59), K. oxytoca (n=10), and E. cloacae (n=6). Compared to our general population, those isolates were more frequently resistant to ciprofloxacin (29% vs. 16%), nitrofurantoin (NTF, 29% vs. 16%), trimethoprim/sulfamethoxazole (TMS 65% vs. 19%) and CTX (12% vs. 7%) (Table, P< 0.05).

Conclusion

KTR are at high risk for the development of AMR, not only to TMPS, which they receive as Pneumocystis jirovecii prophylaxis, but other antibiotic classes as well. KTR-specific institutional antibiograms and targeted AMS interventions, such as provider education against treatment of asymptomatic bacteriuria in KTR, could help improve clinical outcomes and mitigate AMR.

Disclosures

Dimitrios Farmakiotis, M.D., Astra Zeneca: Grant/Research Support|Viracor: Advisor/Consultant|Viracor: Honoraria
P-1575. Trends in antibiotic resistance in community-acquired urinary tract infections among children - a retrospective descriptive nation-wide study
Authors: Yeshurun Michal Stein , Stein Michal , Ben David Shirley Shapiro
Published: January 2025

Background

Urinary tract infection (UTI) is one of the most common bacterial infections in children. Early antibiotic treatment may prevent complications. Empirical treatment requires up-to-date knowledge of the local epidemiology. This study aims to describe trends in resistance rates in community-acquired UTI`s between 2017-2022, assess whether current recommendations for empirical treatment are valid and identify risk factors for resistance.

Methods

Data was collected retrospectively from the computerized system of Maccabi Health Services for all children under 18 years-old diagnosed with a UTI in 2017 and 2022 and analyzed using chi-square test and regression models.

Results

A total of 240,122 urinary samples were included in the study. The most common isolated pathogen was Escherichia coli (78%); there was a slight but significant increase in extended-spectrum beta-lactamases (ESBL) incidence for all Gram-negative Enterobacteriaceae from 6% in 2017 to 8% in 2022, (P-value 0.001). Higher incidence (12%) was detected among Klebsiella isolates compared to E. coli (8%). Aminoglycosides resistance rates increased from 5% to 6% (P-value 0.001). The most impressive increase was in resistance to Fluoroquinolones from 7% to 23% (P-value 0.001).

Female gender, younger age, previous antibiotic treatment and urinary tract abnormalities were associated with an increased resistance rate.

Conclusion

The increased resistance rate observed for most pathogens and antibiotics was statistically significant, nevertheless, due to small absolute changes, the recommendations for empirical antibiotic treatment in Israel are still valid. Fluoroquinolones, which are not recommended as empirical treatment, should be avoided due to high levels of resistance.

Disclosures

Shirley Shapiro Ben David, MD, GSK: Lecturer|Pfizer: Grant/Research Support|Pfizer: Lecturer
P-1586. Urine Culture Reflex Implemented to Reduce Inappropriate Testing
Authors: Orner Erika , Zimilover Adam , Cheng Sammy , Cowman Kelsie , Thwe Phyu , Szymczak Wendy , Gendlina Inessa
Published: January 2025

Background

Improper ordering of urine cultures and patient care based solely on positive culture in the absence of urinalysis suggestive of infection can lead to overtreatment of asymptomatic bacteriuria, increased healthcare costs, and increased risk of antimicrobial-related adverse events like C. difficile infection and increased antimicrobial resistance.

Table 1

Results of specimens collected Oct 24-Nov 4, 2022 pre-implementation

Methods

A reflex urinalysis-to-urine culture was implemented with a threshold of urine culture performed only when 5+ WBC/HPF are seen in urinalysis. Pre-implementation (10/24/22–11/4/22) data from inpatients with concurrent urinalysis and urine culture was analyzed to determine how results would be impacted if urinalysis was utilized as criteria to perform urine culture. Post-implementation (10/24/23–11/4/23) data was also analyzed.

Table 2

Results of specimens collected Oct 24-Nov 4, 2023 post-implementation

Results

Pre-implementation, 1428 urine cultures were done on average per week. During the pre-implementation period, 1695/2273 patients had UA done on the same day as culture. 1376/1695 cultures were negative, 264/1695 cultures were positive, and 55/1695 cultures were contaminated ( ≥3 organisms). Using 5+ WBC/HPF as culture criteria, 1228/1695 (72%) specimens would not have qualified for culture and only 5.8% of cultures would have been falsely negative. Post-implementation, there were 863 urine cultures/week on average. 1125/1513 reflex specimen did not qualify for culture. 375/1513 had 5+ WBC/HPF and qualified for culture but only 140/377 were culture positive. 791/1155 standalone cultures had UA done on the same day. Only 227/791 would have qualified for culture.

Figure 1

Number of urine cultures performed weekly from June to November 2023. Implementation of reflex testing was done Oct 24, 2023

Conclusion

As predicted, using WBCs as criteria to perform urine culture has significantly reduced our urine culture volume. 14% of cultures are still being done without corresponding UA indicating test utilization could further improve. Future studies will analyze the impact reflex testing has on clinical diagnosis and treatment.

Disclosures

Wendy Szymczak, PhD, Quidel: Advisor/Consultant
P-1593. Experience with a Rapid Diagnostic Blood Culture Identification Panel in Patients with Neutropenic Fever
Authors: Patel Dhruv , Mansoor Armaghan-E Rehman
Published: January 2025

Background

Rapid identification of organisms in bloodstream infections can expedite selection of appropriate antimicrobials. This can significantly impact patient care, especially in immunocompromised hosts. Our retrospective study evaluates a single-center experience with a rapid diagnostic blood culture panel (BCID) in patients with neutropenic fever.

Methods

Between January 2020 and October 2023, all adult patients with neutropenic fever for whom blood cultures were obtained were reviewed. As standard protocol, a reflex BCID was performed with the FilmArray© panel for all blood cultures with microbial growth. We evaluated concordance between cultures and BCID data, and clinical implication of discrepant results. Patient demographics, cause of neutropenia, and 90-day mortality was documented.

Results

Of 6382 blood cultures in 1604 episodes for neutropenic fever, 253 unique blood cultures in 189 patients met criteria (Figure 1). Median age was 59 (SD±14.9) years, with 95 (50.3%) being female. A central venous catheter (CVC) was present in 75 patients (39.7%). The most common etiology for neutropenic fever was malignancy or chemotherapy in 124/189 (65.6%), followed by shock in 10/189 (5.3%).

BCID identified resistance genes in 86/253 (34.0%) of samples, with mecA (64, 25.3%) and CTX-M (11, 4.3%) most commonly reported. BCID and routine susceptibility testing showed similar results in 219/253 (86.6%) specimens (Table 1). Of the discordant results, 9/31 BCID results missed presence of an on-target multi-drug resistant organism (Table 2).

A change in therapy occurred based on BCID results from 143 (56.5%) of cultures in 94 (49.7%) of patients. There was no significant difference in 90-day mortality among patients where BCID led to an antibiotic change (37.2% vs 36.8%, p-value=0.96), and no difference in 90-day mortality among patients with discordant data (28.9% vs 37.5%, p-value=0.26).

Conclusion

In 239 episodes of neutropenic fever, BCID results correlated with routine results in 87% of blood cultures. BCID results resulted in quicker change to culture-appropriate antimicrobials in nearly half of the patients, however this was not associated with a mortality benefit.

Disclosures

All Authors: No reported disclosures
P-1614. Verigene's Impact on Time to Preferred Antibiotics in Gram Positive Bacteremia
Authors: Martinez-Palmer Meaghan , Robins Alison
Published: January 2025

Background

Utilization of rapid identification methods for positive blood cultures has been instrumental in the efforts of antimicrobial stewardship programs (ASPs). Studies have shown that the use of molecular testing techniques on positive blood cultures, which identify select bacteria and their genetic resistance, have enabled timelier initiation of targeted therapy.

Type of Bacteremia

Species of bacteremia identified in both the standard identification period and the identification by Verigene period

Methods

Data was collected via chart review over two separate 6-month periods (7/1/2021- 1/1/2022 and 7/1/2022-1/1/2023), with Verigene BCID having been implemented in June 2022. The primary endpoint was the time to preferred therapy for organisms reported in the Verigene gram-positive panel, including MSSA, MRSA, Enterococcus species (faecalis and faecium), VRE, and Streptococcus species. Demographic variables, the source of bacteremia when established (i.e., skin/soft tissue, urinary, etc), as well as interventions for source control were also collected.

Source of Bacteremia

Results

In this study, we analyzed a total of 168 cases of gram-positive bacteremia. Among these, 94 cases occurred between 7/1/2021-1/1/2022 with identification via the standard method, while 74 cases occurred between 7/1/2022-1/1/2023 with identification via Verigene BCID. The average age of patients at the onset of bacteremia was 68 years, with a predominance of males (94.6%). Common underlying comorbidities included diabetes (50%) and coronary artery disease (48.7%).

Regarding bacteremia etiology, 29.8% were caused by MSSA, 22.6% by MRSA, 32.7% by Streptococcus species, 11.3% by Enterococcus spp, and 6% by VRE. The most common primary source of bacteremia was identified as skin and soft tissue (34.5%).

The time to administration of preferred antibiotics, as defined by our ASP recommendations, showed improvement across all gram-positive bacteremia types, decreasing from a mean of 61.5 hours with standard identification methods to 36 hours with Verigene identification. Time to preferred therapy decreased from 81.4 hours to 39.8 hours for MSSA bacteremia, and from 61.9 hours to 39.5 hours for Strep bacteremia.

Time to Preferred Antibiotics

Time in hours to preferred antibiotics for all cases analyzed, Streptococcus species, and MSSA.

Conclusion

The implementation of rapid blood culture identification utilizing Verigene BCID technology lead to a significant improvement in time to preferred antibiotics in cases of gram positive bacteremia.

Disclosures

All Authors: No reported disclosures
P-1615. Inappropriate Urine Cultures: The Order Stops Here
Authors: Hale Molly , Christianson Angela , Casas Mary T , Cronin Jason , Pelz Robert K
Published: January 2025

Background

Our most frequently missed bundle element from catheter-associated urinary tract infection (CAUTI) case reviews was that the urine culture did not meet evidence-based criteria for testing. Possible harm to the patient from an inappropriate urine culture and subsequent treatment includes unnecessary antibiotics, diagnostic anchoring, Clostridioides difficile infection, and longer length of stay. Risks to the organization include artificially inflated infection rates, associated lower quality and safety scores, and reduced federal reimbursements.Figure 1:Catheter-Associated Urinary Tract Infection (CAUTI) Rate

CAUTI rate before (0.61 cases per 1,000 catheter days) and after (0.22 cases per 1,000 catheter days) diagnostic stewardship intervention in March 2022 (p=0.005).

Methods

In March 2022 an automated report was built in a third-party software system using data from the electronic health record to identify urine cultures ordered in a patient hospitalized for two or more days with an indwelling urinary catheter (IUC), or who had an IUC removed in the previous two days. When a qualifying culture was identified, laboratory personnel held results and contacted the Antimicrobial Stewardship (AMS) Pharmacist. The case was discussed at AMS rounds with an Infectious Disease provider and the decision made whether to release the results. In cases where the culture was not appropriate, the patient’s provider was notified that the result would not be finalized and released. The infection rate pre- and post-intervention was calculated, and statistical analysis conducted with the Student’s T-test.

Results

In the 11 months prior to implementation of the urine culture review protocol, the average CAUTI rate was 0.61 cases per 1,000 IUC days. In the 23 months since the intervention, the average CAUTI rate was 0.22 cases per 1,000 IUC days, a 63.9% reduction in the infection rate (p=0.005). 19% of orders reviewed were determined to be appropriate. The AMS team reports the volume of culture reviews is manageable. When notified that the culture results would not be released, ordering providers responded favorably to the decision and no objections or adverse patient outcomes have been observed.

Conclusion

Our non-traditional intervention of enlisting the expertise of the AMS team for a diagnostic stewardship review has been successful in preventing unnecessary treatments to patients and has saved the institution from reportable CAUTI cases that did not meet clinical indication for testing.

Disclosures

All Authors: No reported disclosures
P-1658. Healthcare Provider Perspectives on Antibiotic Use in Immigrants and Refugees in the United States: A Qualitative Study
Authors: Croxton Rachel , Ladines-Lim Joseph , Schurz Timothy , Guetterman Timothy , Patel Payal K
Published: January 2025

Background

Antimicrobial resistance (AMR) is a global health threat with greater prevalence in refugee populations. Prior work demonstrated that compared to native-born Americans, immigrants/refugees from low- and middle-income countries have lower health literacy about AMR, increasing risk for inappropriate antibiotic use. Healthcare provider (HCP) perceptions of prescribing practices regarding immigrant/refugee populations in the United States (US) is lacking. We aimed to understand US HCP views on antibiotic prescribing practices and barriers that may lead to disparities affecting immigrants/refugees.

Methods

From September 1, 2023 through April 27, 2024, as a follow up to patient-centered work on antibiotic knowledge in the immigrant/refugee population, we conducted semi-structured qualitative interviews of 14 HCPs, both prescribers (e.g. physicians, advanced practice providers) and non-prescribers (e.g. nurses, medical assistants), from primary care clinics in SE Michigan that care for immigrants/refugees. We also collected participant demographic information. We generated a codebook through an iterative, inductive process using Dedoose software to code interviews and facilitate thematic analysis.

Results

Self-reported proportions of participants’ patient panels comprised of immigrants, refugees, and non-English speakers were 31.0%, 30.1%, and 48.2% , respectively. Most participants were prescribers and graduate-degree holders (Table 1). Eight major themes emerged: Clinical Decision-Making, Discussing Antimicrobial Consequences, Patient Life Challenges, Patient Medical Background, Antibiotic Use Differences, Patient Perspectives, Clinic Dynamics, and Patient-Provider Communication. There was consensus that distinctive challenges exist for appropriate antimicrobial prescribing among immigrant/refugee populations (Table 2).

Conclusion

Findings suggest that immigrant/refugee populations face multiple barriers to care. This population may benefit from an interdisciplinary outpatient team to navigate cultural differences and trauma-informed care. Our findings can inform ambulatory antibiotic stewardship interventions in immigrant/refugee populations.

Disclosures

All Authors: No reported disclosures
P-1660. Clinical Microbiology of Xylazine-Associated Wound Infections
Authors: Berg Deanna , Maguire Christina , Binkley Amanda , Torgersen Jessie , Hinton Matthew , Peiffer Derek , Huo Samantha , Foster Sean
Published: January 2025

Background

Over 90% of illicit opioids in Philadelphia contain xylazine, a potent centrally acting α-2 adrenergic agonist that can promote the development of skin and soft tissue wounds with a subsequent risk of infection. Optimal wound management, including the need for broad antimicrobial coverage, remains uncertain. This study sought to describe culture positivity and the clinical microbiology of xylazine-associated wounds to inform the optimal antimicrobial spectrum of activity.

Methods

We conducted a retrospective, single-center, cross-sectional study of adults with xylazine-associated wounds between April 1, 2022, and December 1, 2023. Patients were included if they received antimicrobials for suspected wound infection related to injection drug use, along with one of the following: (1) a positive urine xylazine test, (2) a positive urine fentanyl test with patient-reported xylazine use. For patients with multiple hospitalizations and/or wound cultures, the earliest encounter with the single most invasive method of wound culture acquisition was utilized. Microbiology results and causative pathogens are reported.

Results

Of the 685 patients with positive urine toxicology, 166 were included in the analysis, and 56% had positive cultures. Wound cultures were obtained in 81 (49%) patients; superficial bedside cultures were the only culture type obtained in 61% of patients, and operative cultures were collected in 39% of patients. Methicillin-resistant Staphylococcus aureus (MRSA) was the most common causative pathogen, and Pseudomonas aeruginosa was isolated in 9% of patients, most of whom had a bone or joint infection (88%). Nearly one in four patients were bacteremic (Table 1).

Conclusion

Over half of patients with suspected infected xylazine-associated wounds had clinical microbiology results to guide antimicrobial therapy. Gram-positive organisms were most frequently isolated, while gram-negative organisms were infrequently observed. These observations suggest that suspected infected xylazine-associated wounds should include empiric coverage of MRSA and β-hemolytic streptococci. Empiric anti-pseudomonal and/or anaerobic coverage may not be necessary for most patients being treated for skin and soft tissue infections.

Disclosures

Christina Maguire, PharmD, Viiv: Advisor/Consultant Amanda Binkley, PharmD, BCIDP, AAHIVP, Viiv: Advisor/Consultant
P-1698. Prevalence of Anaerobes, Enterococcus, and Pseudomonas Among Patients with Complicated Biliary Infections
Authors: Mitsuuchi Taylor , Lau Janice , Hori Mike , Huang Joanne
Published: January 2025

Background

Current 2010 Infectious Diseases Society of America (IDSA) guidelines indicate that community acquired biliary infections do not require antimicrobial therapy directed against Enterococcus spp., Pseudomonas (PSA), or anaerobes in the absence of select risk factors. We evaluated empiric prescribing practices for complicated biliary infections at Valley Medical Center (VMC).

Methods

This was a single center retrospective study including patients 18 years or older with complicated biliary infections admitted at VMC from 1/1/2018 - 2/28/2022. Patients who did not require surgical intervention, had no cultures collected, or noted cephalosporin allergy were excluded. The primary outcome was to evaluate the prevalence of anaerobic, Enterococcus spp., and PSA bacteria isolated from culture. Secondary outcomes evaluated rate of Intensive Care Unit (ICU) admissions, all cause 30-day readmission, and C. difficile infections (CDI).

Results

191 patients with complicated biliary infections with culture data were included. Anaerobes and Enterococcus spp. were the most commonly isolated organisms, accounting for 19.4% and 11.5%, respectively. Of anaerobic cultures obtained, 6 (3.1%) were identified as gram-negative anaerobes and 26 (13.6%) were identified as gram-positive anaerobes. Pseudomonas spp. was uncommon (0.5%). 78 (40.8%) had negative cultures. 85 (44.5%) received empiric ceftriaxone. Of those on ceftriaxone, 75 also received metronidazole. 88 (46.1%) received empiric piperacillin tazobactam and the remaining 18 patients received alternative therapies. 59 (30.9%) were either admitted or transferred to ICU during their index admission. Of these, 48 (81.4%) were on piperacillin tazobactam. Similar all-cause 30-day readmission was observed among patients on ceftriaxone and piperacillin tazobactam (43.4%). Diagnosis with CDI within 90 days of discharge was uncommon (1.6%).

Conclusion

PSA and Gram-negative anaerobe prevalence was low; Enterococcus and Gram-positive anaerobes was higher. Lower rates of ICU admission and CDI were observed in patients on ceftriaxone, though may be in part due to less severe illness. Additional studies are needed to evaluate risk factors that may be predictive of Enterococcus and anaerobic infection.

Disclosures

All Authors: No reported disclosures
P-1710. Prescribing Patterns for Clostridioides difficile Treatment in Outpatient Setting Using the Collaboration to Harmonize Antimicrobial Registry Measures (CHARM)
Authors: Nandi Tiasha , Pawlowski Kathryn M , Pontefract Benjamin , Klepser Michael , Sohn Minji
Published: January 2025

Background

Clostridioides difficile infection (CDI) is a form of infectious diarrhea associated with antibiotic use. In 2021, the IDSA released guidelines for treatment of CDI, which recommended fidaxomicin for 10 days as the first line treatment and vancomycin as an acceptable alternate. It is unclear to what extent prescribers have adopted this recommendation. This study aimed to examine patients’ antibiotic exposure before developing CDI and describe the prescribing patterns for CDI treatment in outpatient settings.Table 1:Frequency and Duration of Initial Clostridioides difficile Infection (CDI) Therapy

Methods

This observational study used the CHARM database, which contains outpatient encounter data extracted from the medical records of nine health systems. Patients with CDI were identified using ICD-10 codes and medications commonly used for CDI. The data period was between July 2019 and June 2023. The frequency and duration of antibiotics used for CDI treatment and the percentage of patients receiving subsequent therapy were estimated. Antibiotics prescribed within 180 days prior to a diagnosis of CDI visit were captured.Figure 1:Duration Distribution of Initial Clostridioides difficile Infection (CDI) Therapy

Results

A total of 551 patients with CDI were identified. Of those, 439 (80%) received vancomycin, 80 (15%) received fidaxomicin, and 52 (9%) received metronidazole. The average duration of therapy in days for vancomycin, fidaxomicin, and metronidazole was 12, 8, and 10, respectively (Table 1). The most common duration of therapy was 7-days for vancomycin (46%), fidaxomicin (41%), and metronidazole (50%) (Figure 1). After the initial treatment, 4% received a subsequent treatment within 3 weeks. Fluoroquinolone prescriptions had the highest prevalence of CDI (3.6 cases per 10,000 prescriptions). Of patients with an identified antibiotic 30 days prior to CDI, 38% had multiple courses of antibiotics.

Conclusion

Receiving multiple courses of antibiotics is associated with developing CDI. The majority of patients with CDI received vancomycin treatment (the alternative recommended therapy). The average duration of therapy was longer than recommended. Metronidazole use is still common.

Disclosures

Minji Sohn, PhD, Emergent BioSolutions, Inc.: Grant/Research Support
P-1717. Perception and Practice of Physicians' Antibiotic Use at Tertiary Military Hospitals in Bangladesh
Authors: Hassan Syed Abul , Saha Sharmi , Dostogir Harun Md Golam , Amin Sumon Md Shariful , Jahan Ishrat , Ul Anwar Md Mahabub , Siddiquee Taufiq H
Published: January 2025

Background

Inappropriate use of antibiotics, which contributes to increased antimicrobial resistance (AMR), is common in healthcare settings across the globe, especially in low-resources settings. Antibiotics are widely and inappropriately used without adherence to international guidelines in Bangladesh, which may contribute significantly to the development AMR. Military hospitals are known for better compliance of health care system. We sought to investigate the perceptions of Physicians of Tertiary military hospitals in Bangladesh regarding appropriate antibiotic use and prescribing approach.

Physicians' AMR perception

Methods

We conducted a cross-sectional survey using a semi-structured questionnaire and data collected through face to face interview from 84 Military doctors of two major tertiary military hospitals of Bangladesh – Combined Military hospital (CMH) Dhaka (1650 bedded) and Jashore (500 bedded) between September 2020 and January 2021. Descriptive statistics were performed to analyze the data and for interpretation

Approach of physician to prescribing antibiotic

Results

Out of 84 respondents, 70% of the physicians considered AMR is a significant concern worldwide, but only 26.7% Physician of Dhaka CMH and 11% of Jashore CMH considered it as a problem in their hospital. Two-third respondent (66%) considered that inappropriate use of antibiotic is the main cause of rising AMR, followed by Over prescription of broad-spectrum antibiotics by 62.2%, and Easy access to antibiotics without a prescription by 58.8%. Around 36.2% opined that poor IPC practices by health professionals are also important factor. Total 72.6% respondent ensure that they routinely step down I/V antibiotics to oral antibiotics as earliest, 13.4% physicians considered cost affordability of the patient affects their choice of antibiotics. Over half of the physicians (51.2%) use prophylactic antibiotic for 3 to 7 days after any surgical procedure of a clean-contaminated case without signs of infection, where only 7.3% doctor use single dose antibiotic prophylaxis.

Use of antibiotic prophylaxis in surgical procedure

Conclusion

Physicians' perception on AMR and rational antibiotic prescription were found fall of short of the standard. Strict compliance of antibiotic use and trade guideline, Introduction of formal antibiotic stewardship program in Bangladesh may be a useful intervention

Disclosures

All Authors: No reported disclosures
P-1718. Use of Collaboration to Harmonize Antimicrobial Registry Measure (CHARM) to Assess Antibiotic Prescribing in Dental Practices
Authors: Smith Cameron , Sohn Minji , Pontefract Benjamin , Dahal Kushal , Klepser Michael , Mishreky Helen
Published: January 2025

Background

Dentists account for 10% of all antibiotic prescriptions in the United States. Limited data exist describing antibiotic use in dental practices; however, it appears that many antibiotics may not be warranted or consistent with treatment guidelines.1,2,3 Of particular concern is the unwarranted use of clindamycin. No standardized methods exist for gathering data and assessing the concordance of use related to antibiotic use in dental practices.

Objectives

Describe patterns of antibiotic prescribing in dental clinics within the CHARM network. Identify areas for stewardship intervention within dental practices. top 5 antibiotic prescription in dental clinics

name of antibiotic, the number of prescriptions, percentages, and average duration

Methods

Dental practices were identified from 5 dental clinics that participate in CHARM. The CHARM database is a registry containing data collected from the electronic medical records of partnering health systems about outpatient antibiotic prescribing. Episodes of antibiotic prescribing were identified in dental clinics and extracted between January 2022 to June 2023. Data collected included the ICD-10 code, antibiotic, and regimen used. When a diagnosis was provided, the appropriateness of antibiotic selection was assessed in concordance with guidelines. The most common antibiotics and diagnoses were identified.

Results

4,028 antibiotic prescriptions were written by 42 prescribers in 5 dental clinics. The most prescribed antibiotics were amoxicillin (n=2,400; 59.6%), penicillin (n=700;17.3%), and clindamycin (n=400;9.9%). The average length of therapy was 7.0, 8.2, and 6.9 days for amoxicillin, penicillin, and clindamycin, respectively. ICD-10 codes were recorded for 1,722 (43%) prescriptions. No indication/diagnosis was provided for 2,278 (57%) antibiotic prescriptions. While many prescriptions were not linked to any diagnosis (n=2,300; 57.1%), the most common diagnosis codes were general dental exam (n=1,400; 34.8%) and general dental infection (n=300; 7.4%).

Conclusion

For visits where the dentist prescribed antibiotics, clindamycin was prescribed about 10% of the time. Clindamycin is no longer recommended for use in most procedures that dentists manage.4 Reducing clindamycin use in dental practices represents a stewardship opportunity in dental practices.

Disclosures

Minji Sohn, PhD, Emergent BioSolutions, Inc.: Grant/Research Support
P-1722. Short versus Long Duration of Empiric Antifungal Use Among Patients with Sepsis or Septic Shock
Authors: Rust Thomas J , Binkley Shawn , DiCesare Michael , Lawson Shannon , Athans Vasilios
Published: January 2025

Background

Invasive candidiasis is associated with high mortality rates among critically ill patients. There are currently no data to guide duration of empiric antifungal therapy (EAT) when indicated in high-risk patients with sepsis. The aim of this study was to evaluate clinical outcomes associated with a short versus long course of EAT in patients with sepsis or septic shock.

Methods

This was a retrospective cohort study of adults admitted to the medical ICU who received > 2 days of EAT with fluconazole or caspofungin for sepsis or septic shock. Patients were excluded if they expired within 48 hours, had a positive fungal culture from a sterile site, were exposed to a systemic antifungal for > 48 hours in the 14 days preceding treatment, received prophylactic antifungals, or were neutropenic. In addition, patients who expired within 96 hours of EAT initiation were excluded from the primary outcome analysis. Patients were grouped according to receipt of EAT for ≤ 4 days (short duration) or > 4 days (long duration). The primary outcome was 30-day all-cause mortality. Secondary outcomes included time to mortality, hospital and ICU length of stay (LOS), vasopressor-free days over 14 days, and 30-day new proven fungal infection.

Results

Of 135 included patients, 79 patients received short course EAT vs. 56 patients long course (Figure 1). Baseline variables were well balanced between groups apart from older age and lower body weight observed in the short duration group (Table 1). The primary outcome, evaluable in a total of 114 patients, was observed in 33 (56.9%) patients who received a short duration and 26 (46.4%) patients who received a long duration (p=0.263; OR 1.52, 95% CI [0.73 – 3.19]). There were no significant differences in all-cause inpatient mortality or time to mortality (Figure 2). Among patients who were discharged alive, there were no significant differences in secondary outcomes with the exception of fewer vasopressor-free days in the short course group (Table 2).

Conclusion

Most clinical outcomes were not significantly different between patients with sepsis or septic shock who received a short versus long course of EAT. Duration of EAT is an important target for stewardship programs. This study adds to knowledge in the area, though a randomized trial may be necessary to substantiate our findings.

Disclosures

All Authors: No reported disclosures