Percentage Of Susceptibility Research Articles

Antifungal Potency of Some Antifungal Chemotherapeutics and Antidandruff Solutions against Dermatophytic Flora from Local Hairdressers’ Tools in Awka, Nigeria

Dermatophytes produce spores that can survive for a long time on fomites such as hairdressing tools (combs, scissors, clippers and hairpins). These fomites intend serve in the transmission of dermatophytosis. This study was aimed at evaluating and comparing the antifungal efficacy of some antifungal chemotherapeutics and antidandruff solutions against dermatophytic flora of hairdressers’ tools in Eke-Awka Market in Awka, Anambra State, Nigeria. A total of forty-five (45) samples were collected by swabbing the hairdressing tools of the local hair dressers using sterile swab sticks. The antifungal drugs (Ketoconazole, Miconazole and Griseofulvin) and the antidandruff solutions (Shampoo and Conditioner) were also bought from Eke-Awka Market. The samples where inoculated into sterile Sabouraud Dextrose Broth base in test tubes and incubated at 25-27ºC for 5-14 days. After incubation, the test tubes with visually observed growth (turbidity) were subsequently plated out by streaking on freshly prepared Sabouraud Dextrose Agar supplemented with Chloramphenicol (50µg/ml) and incubated at 25°C for up to 7-14 days. Identification was done using standard methods. Agar well diffusion method was employed for the in vitro antifungal susceptibility testing using different concentrations of both the antifungal drugs and antidandruff solutions obtained using double fold serial dilutions. Twenty Four (24) dermatophytes were isolated and identified. The isolates included Microsporum ferrugineum 6 (25%), Microsporum gypseum 3 (12.5%), Micosporum audouinii 6 (25%), Trichophyton schoenleinii 5 (20.8%) and Trichophyton mentagrophytes 4 (16.7%). The percentage susceptibility pattern of the isolates showed that 60℅ of the isolates were susceptible to Ketoconazole, 40℅ respectively susceptible and susceptible doze dependent to Miconazole and 100℅ resistant to Griseofulvin. For the antidandruff solutions, 20℅ of the isolates were susceptible to hair shampoo while 100℅ were resistant to hair conditioner. The results of this study showed that dermatophytes are prevalent on the tools used by local hair dressers and also that the antifungal drugs had better activity on the isolates than the antidandruff solutions used. Also, based on this study, ketoconazole is recommended for dermatophytosis. There is therefore need to educate the populace on the health hazards associated with sharing local hair making tools and the need for clients to have their personal hair making tools.

Dynamic Imaging of Blood Coagulation Within the Hematoma of Patients With Acute Hemorrhagic Stroke.

The dynamics of blood clot (combination of Hb [hemoglobin], fibrin, and a higher concentration of aggregated red blood cells) formation within the hematoma of an intracerebral hemorrhage is not well understood. A quantitative neuroimaging method of localized coagulated blood volume/distribution within the hematoma might improve clinical decision-making. The deoxyhemoglobin of aggregated red blood cells within extravasated blood exhibits a higher magnetic susceptibility due to unpaired heme iron electrons. We propose that coagulated blood, with higher aggregated red blood cell content, will exhibit (1) a higher positive susceptibility than noncoagulated blood and (2) increase in fibrin polymerization-restricted localized diffusion, which can be measured noninvasively using quantitative susceptibility mapping and diffusion tensor imaging. In this serial magnetic resonance imaging study, we enrolled 24 patients with acute intracerebral hemorrhage between October 2021 to May 2022 at a stroke center. Patients were 30 to 70 years of age and had a hematoma volume >15 cm3 and National Institutes of Health Stroke Scale score >1. The patients underwent imaging 3×: within 12 to 24 (T1), 36 to 48 (T2), and 60 to 72 (T3) hours of last seen well on a 3T magnetic resonance imaging system. Three-dimensional anatomic, multigradient echo and 2-dimensional diffusion tensor images were obtained. Hematoma and edema volumes were calculated, and the distribution of coagulation was measured by dynamic changes in the susceptibilities and fractional anisotropy within the hematoma. Using a coagulated blood phantom, we demonstrated a linear relationship between the percentage coagulation and susceptibility (R2=0.91) with a positive red blood cell stain of the clot. The quantitative susceptibility maps showed a significant increase in hematoma susceptibility (T1, 0.29±0.04 parts per millions; T2, 0.36±0.04 parts per millions; T3, 0.45±0.04 parts per millions; P<0.0001). A concomitant increase in fractional anisotropy was also observed with time (T1, 0.40±0.02; T2, 0.45±0.02; T3, 0.47±0.02; P<0.05). This quantitative neuroimaging study of coagulation within the hematoma has the potential to improve patient management, such as safe resumption of anticoagulants, the need for reversal agents, the administration of alteplase to resolve the clot, and the need for surgery.

Genomic diversity of β-lactamase producing Pseudomonas aeruginosa in Iran; the impact of global high-risk clones

BackgroundHospital-acquired infections caused by multidrug-resistant Pseudomonas aeruginosa incline hospital stay and costs of treatment that resulted in an increased mortality rate. The frequency of P. aeruginosa high-risk clones producing carbapenemases was investigated in our clinical samples.MethodsIn this cross-sectional study, 155 non-repetitive P. aeruginosa isolates were included from different medical centers of Iran. Antibiotic susceptibility testing was determined, and the presence of β-lactamases were sought by phenotypic and genotypic methods. The clonal relationship of all isolates was investigated, and multi-locus sequence typing (MLST) was used for finding the sequence types of carbapenemase-producers.ResultsThe agent with highest percent susceptibility rate was recorded for colistin (94.9%). MOX and FOX were found both as low as 1.95% (3/155). The most frequent narrow spectrum β-lactamase was SHV with 7.7% (12/155) followed by PER, OXA-1, and TEM with the frequency of 7.1% (11/155), 3.2% (5/155), and 1.3% (2/155), respectively. Carbapenemases were detected in 28 isolates (18%). The most frequent carbapenemase was IMP with 9% (14/155) followed by NDM, 8.4% (13/155). OXA-48 and VIM were also detected both per one isolate (0.65%). MLST of carbapenem resistant P. aeruginosa isolates revealed that ST244, ST664, ST235, and ST357 were spread in subjected clinical settings. REP-PCR uncovered high genomic diversity in our clinical setting.ConclusionClonal proliferation of ST235 strain plays a key role in the propagation of MDR pattern in P. aeruginosa. Our data showed that high-risk clones has distributed in Iran, and programs are required to limit spreading of these clones.

Comparative antibiogram of annual antimicrobial susceptibility trend in a tertiary care institution in Telangana with ICMR annual AMR report for the year 2021

Introduction: Antibiogram data can improve hospital antibiotic formulary decisions and local protocols such as surgical prophylaxis or empirical treatment guidelines. This study aims to compare the antimicrobial resistance (AMR) trends observed in our institution with the national data published by the Indian Council of Medical Research (ICMR). Methods: The annual antibiogram of all common clinical isolates received in the hospital in 2021 was constructed as per the consensus guidelines developed by the Clinical and Laboratory Standards Institute, and the antimicrobial susceptibility trends were compared with the Indian Council of Medical Research annual Antimicrobial Resistance Report for 2021. Results: A total of 719 first isolates (excluding duplicate isolates) of common organisms viz., Escherichia coli (n = 198), Klebsiella pneumoniae (n = 164), Pseudomonas aeruginosa (n = 70), methicillin-sensitive Staphylococcus aureus (MSSA) (n = 174), methicillin-resistant Staphylococcus aureus (MRSA) (n = 39), Enterococcus species (n = 74) were analyzed and described as in charts. Discussion: The percentage susceptibility of gram-positive isolates to vancomycin, linezolid, tetracycline, nitrofurantoin, and fosfomycin was comparable to the national ICMR AMR report, whereas there were differences in the susceptibility rates to other antimicrobial agents such as penicillin, ampicillin, erythromycin, clindamycin, and co-trimoxazole. The percentage susceptibility of P. aeruginosa isolates was comparable to the national ICMR AMR report for all anti-pseudomonal agents tested and analyzed. The gram-negative isolates showed better susceptibility rates to the beta-lactam antibiotics, fluoroquinolones, and carbapenems in comparison to the national ICMR AMR report. Conclusion: Analysis of antibiograms from different regions of our country would show us the trends and patterns of antimicrobial resistance.

2784. Rates of Susceptibility and Heteroresistance to Novel Antibiotic Combinations in Carbapenem-Resistant Enterobacterales Isolates - Emory Healthcare, 2016-2021

Abstract Background CRE infections are frequently treated with new beta-lactam/beta-lactamase inhibitors (BL/BLI): imipenem-relebactam (I-R), ceftazidime-avibactam (CZA), and meropenem-vaborbactam (MVB). However, the frequency of susceptibility and heteroresistance (HR), defined as the presence of an antibiotic-resistant subpopulation within a primary susceptible population, to these newer antibiotics is unknown. Here we evaluate rates of susceptibility and HR to newer BL/BLI in a convenience sample of clinical CRE isolates as potential reasons for clinical failure. Methods We created an antibiogram for carbapenem-resistant Enterobacter cloacae, Escherichia coli and Klebsiella pneumoniae isolates collected between 2016–2021 as part of routine clinical care from two &amp;gt;500-bed academic hospitals. We tested the first isolate per patient for susceptibility to I-R, CZA, and MVB by broth microdilution. We used population analysis profiling (PAP) to test for HR to CZA and I-R. Results Of 328 CRE isolates, 74 (22%) were from sterile sites, 151 (46%) from urine, 43 (13%) from the respiratory tract, and 60 (18%) from other non-sterile sites. For E. cloacae (n=152), 93% were susceptible to I-R, 98% to CZA, and 99% to MVB. For E. coli (n=53), 89% were susceptible to I-R, 94% to CZA, and 93% to MVB. For K. pneumoniae (n=123), 90% were susceptible to I-R, 94% to CZA, and 93% to MVB (Table 1). Over time, decreases in the activity of all 3 BL/BLI were noted. Compared to 2016, the percentage of susceptible CRE isolates decreased by 11% (98% to 87%) for I-R, 7% (98% to 91%) for CZA, and 8% (98% to 90%) for MVB (Figure 1). The percentage of isolates with HR to CZA was 7.2% for E. cloacae, 1.9% for E. coli, and 4.9% for K. pneumoniae. For I-R, the percentage of HR isolates was 4.1% for E. cloacae, 9.6% for E. coli, and 10.3% for K. pneumoniae.Table 1.Proportion of carbapenem-resistant Enterobacterales isolates susceptible to new beta-lactam/beta-lactamase inhibitors in two academic hospitals. N = number of antibiotic susceptible isolates, followed by percentage (%) of susceptible isolates. Asterisk (*) indicates if not all isolates were tested against the specified antibiotic. I-R = imipenem-relebactam CZA = ceftazidime-avibactam MVB = meropenem-vaborbactam The percent susceptibility of carbapenem-resistant Enterobacterales isolates to the specified antibiotic was graphed per year for all isolates and by individual species. The isolates from two academic hospitals were combined. I-R Sus % = Percent susceptibility to imipenem-relebactam MVB Sus % = Percent susceptibility to meropenem-vaborbactam CZA Sus % = Percent susceptibility to ceftazidime-avibactam Conclusion In our study on the activity of newer BL/BLI against CRE, susceptibility remains high and HR is rare. While newer BL/BLIs remain highly active against CRE, the observed decrease in susceptibility over time suggests a need for ongoing antibiotic stewardship. Disclosures Ahmed Babiker, MBBS, Roche: Advisor/Consultant

1253. Optimization of empiric gram-negative infections with the combination antibiogram

Abstract Background Anti-pseudomonal beta-lactam drugs such as aztreonam (AZR), cefepime (CEF), piperacillin-tazobactam (P/T), meropenem (MER) are drugs used for empiric gram-negative (GN) infections. They are used with other drugs as empiric combination therapy (CT) for patients with sepsis. The antibiogram is used to provide data for empiric therapy and gauge susceptibility pattern shifts over time. Combining different classes of drugs might enhance the susceptibility to various pathogens. This project assessed which empiric combination of drugs will yield optimal coverage for various GN pathogens from different sources. Methods In 2022 antimicrobial susceptibility data from 8288 isolates from blood, respiratory, wound and urine sources were collected and analyzed. Percent susceptibility was calculated for 11 gram-negative species with &amp;gt;30 isolates. Susceptibility testing was done by BD Phoenix™ automated identification and susceptibility testing system. A threshold of &amp;gt;90% susceptibility was used to indicate optimal coverage for the antimicrobial agents. CT is calculated as the % susceptible to either of two antibiotics. Results In respiratory sources AZR, CEF and P/T were the lowest at 73%, 83% and 77% susceptible. MER had the best overall coverage for all specimen types. Adding either an aminoglycoside (AG) or fluoroquinolone (FQ) increased susceptibility in all sources. AGs had a slightly better coverage than FQs. For blood isolates &amp;gt; 90% susceptibility was attained for single antibiotics without combination. CT was often required to achieve optimal coverage for respiratory sources, specifically for Pseudomonas, Enterobacter, E coli, Klebsiella and Proteus species.Figure 1.Combination antibiogram for beta-lactam agents for gram-negative respiratory isolates as monotherapy or in combination with ciprofloxacin, gentamicin, or tobramycin.*All gram-negative isolates included Serratia and Providencia species that were not included in the subgroups. Conclusion Using &amp;gt; 90% susceptibility as cut-off, monotherapy AZR and P/T are suboptimal for empiric coverage for certain GN respiratory infections. Blood specimens may not require CT. Adding either AGs or FQs enhanced susceptibility coverage to all tested pathogens but not uniformly. AGs enhancement was slightly better than FQs. Respiratory infections with Pseudomonas, Enterobacter cloacae, E coli, Proteus and Klebsiella species all showed enhanced coverage with CT especially for P/T and AZR. Every hospital should create a combination antibiogram to gain insight into whether empiric coverage with CT is needed. Disclosures All Authors: No reported disclosures

In vitro activity of tebipenem and comparator agents against bacterial pathogens isolated from patients with cancer

Abstract Background Tebipenem is a broad-spectrum orally administered carbapenem antibiotic that could be an alternative to IV carbapenems. The current study evaluated in vitro activity of tebipenem against bacterial isolates recovered from patients with cancer. Methods A total of 611 bacterial pathogens recently isolated from patients with cancer were tested for susceptibility to tebipenem and comparators. CLSI-approved broth microdilution methods were used. MIC50, MIC90, MIC range and percentage susceptibility calculations were made using FDA breakpoints when available. Results Tebipenem had a low MIC90 for most Gram-positive and Enterobacterales isolates. Tebipenem MIC90 ranged from 0.06 to 0.25 mg/L for all tested Enterobacterales. Conclusions Oral tebipenem has promising activity against clinically significant bacterial pathogens isolated from patients with cancer. Further clinical evaluation of tebipenem for the treatment of bacterial infections in patients with cancer is warranted.

Decreasing Antibiotic Resistance Trends Nationally in Gram-Negative Bacteria Across United States Veterans Affairs Medical Centers, 2011-2020.

Gram-negative resistance is a well-acknowledged public health threat. Surveillance data can be used to monitor resistance trends and identify strategies to mitigate their threat. The objective of this study was to assess antibiotic resistance trends in Gram-negative bacteria. The first cultures of Pseudomonas aeruginosa, Citrobacter, Escherichia coli, Enterobacter, Klebsiella, Morganella morganii, Proteus mirabilis, and Serratia marcescens per hospitalized patient per month collected from 125 Veterans Affairs Medical Centers (VAMCs) between 2011 to 2020 were included. Time trends of resistance phenotypes (carbapenem, fluoroquinolone, extended-spectrum cephalosporin, multi-drug, and difficult-to-treat) were analyzed with Joinpoint regression to estimate average annual percent changes (AAPC) with 95% confidence intervals and p values. A 2020 antibiogram of reported antibiotic percent susceptibilities was also created to evaluate resistance rates at the beginning of the COVID-19 pandemic. Among 40 antimicrobial resistance phenotype trends assessed in 494,593 Gram-negative isolates, there were no noted increases; significant decreases were observed in 87.5% (n = 35), including in all P. aeruginosa, Citrobacter, Klebsiella, M. morganii, and S. marcescens phenotypes (p < 0.05). The largest decreases were seen in carbapenem-resistant phenotypes of P. mirabilis, Klebsiella, and M. morganii (AAPCs: - 22.9%, - 20.7%, and - 20.6%, respectively). In 2020, percent susceptibility was over 80% for all organisms tested against aminoglycosides, cefepime, ertapenem, meropenem, ceftazidime-avibactam, ceftolozane-tazobactam, and meropenem-vaborbactam. We observed significant decreases in antibiotic resistance for P. aeruginosa and Enterobacteralesover the past decade. According to the 2020 antibiogram, in vitro antimicrobial activity was observed for most treatment options. These results may be related to the robust infection control and antimicrobial stewardship programs instituted nationally among VAMCs.

Antibiograms of select anaerobic bacteria over 10 years

Abstract Antibiotics are critical complements to the immune response in combatting infection. Anaerobic bacteria are increasingly common causes of infection, and antibiotic resistance of anaerobes has been rising. Most laboratories do not perform antimicrobial susceptibility testing of anaerobes, and even fewer have compiled antibiogram data. Here we investigated antimicrobial susceptibility results of anaerobes from January 2012 to December 2021 obtained from inpatients at Mayo Clinic using reference agar dilution testing. Actinomyces (60–70 isolates annually), Bacteroides fragilis (30–80), Finegoldia magna (40–60), and Cutibacterium acnes (70–110) were included. Penicillin, clindamycin, metronidazole, ertapenem, piperacillin-tazobactam, and moxifloxacin were tested. Clinical and Laboratory Standards (CLSI) breakpoints were followed. B. fragilis showed ≥90% and Actinomyces 100% susceptibility to piperacillin-tazobactam and ertapenem. All F. magna and &amp;gt;95% B. fragilis were susceptible to metronidazole. The most striking fluctuations in percent susceptibility from year to year were observed for clindamycin, with Actinomyces ranging from 66–79%, B. fragilis 34–67%, and F. magna 47–85%. In the absence of local anaerobe antibiograms, providers may refer to such antibiogram data to guide empiric anti-anaerobic therapy at their institutions. In conclusion, anaerobe antibiotic susceptibility patterns must be monitored to ensure appropriate antibiotic empiric therapy and stewardship.

Antimicrobial susceptibility patterns from urinary isolates obtained from cats (2013‐2020)

Bacterial urinary tract infections have been associated with comorbidities and increased antimicrobial resistance over time. To identify bacterial species, antimicrobial susceptibility patterns and risk factors associated with antimicrobial resistance. Three hundred sixty-three positive urine cultures from 308 cats. Bacterial species and antimicrobial susceptibility data from positive aerobic bacterial urine cultures from cats with growth of ≥103 colony forming units per milliliter (cfu/ml) were included. Medical records were reviewed, and bacteriuria was classified as sporadic bacterial cystitis, recurrent bacterial cystitis or subclinical bacteriuria (SBU). Multivariable logistic regression analysis was used to evaluate antimicrobial resistance risk factors. A total of 444 bacterial isolates from 363 bacteriuric episodes were identified. Escherichia coli (52%) and SBU (59%) were the most common organism and classification, respectively. When compared to other classifications of bacteriuria, Enterococcus spp. were more likely to be isolated from SBU episodes (P < .001), whereas E. coli was more likely to be isolated from sporadic bacterial cystitis episodes (P < .001). Recurrent bacterial cystitis was associated with an increased risk of antimicrobial resistance to amoxicillin/clavulanic acid (odds ratio [OR], 3.9; 95% confidence interval [CI], 1.3-11.3). The percent susceptibilities of all bacterial isolates to commonly prescribed antimicrobials were amoxicillin/clavulanic acid (72%), cefazolin (49%), enrofloxacin (61%), and trimethoprim/sulfamethoxazole (75%). Multidrug resistance was highest for Enterococcus faecium isolates (65%). No antimicrobial achieved >90% susceptible designation to all bacteria isolated highlighting the importance of performing urine culture and susceptibility testing, particularly for cats with recurrent bacterial cystitis.

Comparative in vitro antipseudomonal activity of ceftolozane/tazobactam against Pseudomonas aeruginosa isolates from children with cystic fibrosis

This study evaluated the in vitro activity of Ceftolozane/tazobactam (C/T) vs 10 comparator agents against Pseudomonas aeruginosa isolates obtained from clinical respiratory samples from pediatric patients with cystic fibrosis at three hospitals during 2015 to 2020. Antimicrobial susceptibility testing was performed using microbroth dilution technique with custom prepared Sensititre® MIC plates. MICs were determined via Sensititre Vizion® system and results were interpreted using current CLSI and EUCAST (2022) breakpoint criteria. C/T was the most potent agent as compared with other antipseudomonal drugs against 291 isolates with MIC50 = 1 μg/mL and MIC90 = 2 μg/mL with percent susceptibility as 95.2%. C/T remained active against majority of ß-lactam non-susceptible isolates; percent susceptibility ranging from 61.2% to 80% including 65.9% ceftazidime non-susceptible isolates. C/T had high activity against P. aeruginosa from 3 geographically diverse pediatric medical centers. Study results suggest that C/T may be used as a potential therapeutic option for treating pediatric patients with CF.

942. Comparison of Antibiotic Susceptibility Across Minnesota Hospitals in 2019 and 2020 Using a New Statewide Antibiogram

Abstract Background Surveillance is imperative to successful antibiotic stewardship, but active surveillance is resource-intensive. Regional antibiograms provide a supplementary method of surveillance while conserving resources. We developed the first statewide antibiograms to track susceptibility across the state of Minnesota and compared 2019 and 2020 data. Methods Hospital antibiograms for 2019 and 2020 were submitted to the Minnesota Department of Health in January 2022. Twelve organisms (Enterococcus faecalis, Enterococcus faecium, methicillin-resistant Staphylococcus aureus, methicillin-susceptible S. aureus, S. aureus, Acinetobacter spp., Enterobacter spp., Escherichia coli, Klebsiella aerogenes, K. oxytoca, K. pneumoniae, and Pseudomonas aeruginosa) were selected for analysis against 32 drugs, leading to a total of 142 unique organism/agent combinations. The number of isolates and percent susceptibility from each antibiogram were used to calculate a weighted average percent susceptibility as the state-level susceptibility. Chi-square analysis compared the proportion of susceptible to non-susceptible isolates between the years. Results Submitted antibiograms (n=40) represented 30% of Minnesota hospitals. The total number of isolates reported decreased by 5% from 2019 (n=85,010) to 2020 (n=80,781), with E. coli having the greatest proportion (2019=41.7%, 2020=39.5%) of the total isolates. Significant changes in susceptibility proportions occurred in 33% of analyzed organism/agent combinations, with 68% of these showing increased susceptibility in 2020 compared to 2019. All antibiotics tested against P. aeruginosa demonstrated a statistical increase in susceptibility from 2019 to 2020 (Figure 1). Figure 1 Statewide susceptibility profile of P. aeruginosa in Minnesota, 2019 and 2020. Antimicrobial agents grouped by class from narrow spectrum to broad spectrum, cephalosporins ordered by generation. *denotes statistical significance (p&amp;lt;0.05). Conclusion Analysis of statewide antibiograms for 2019 and 2020 demonstrated overall stability in antimicrobial susceptibility, with two-thirds of organism/agent combinations showing no significant changes. In those with significant changes, the majority exhibited an increase in susceptibility. Susceptibility changed more frequently in gram-negative organisms than gram-positive organisms. Ongoing collection of antibiograms will be used to assess regional and statewide susceptibility trends across Minnesota. Disclosures Elizabeth B. Hirsch, PharmD, FCCP, FIDSA, Melinta: Advisor/Consultant|MeMed: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support.

2176. In Vitro Evaluation of Delafloxacin Activity Against Contemporary US Isolates from Cystic Fibrosis Patients Hospitalized with Pneumonia: Results from the SENTRY Antimicrobial Surveillance Program (2019-2021)

Abstract Background Delafloxacin (DLX) is a broad-spectrum fluoroquinolone antibacterial approved in the US for the treatment of community-acquired bacterial pneumonia (CABP) and acute bacterial skin and skin structure infections. DLX is indicated to treat CABP caused by multiple pathogens, including methicillin-susceptible Staphylococcus aureus (MSSA) and Pseudomonas aeruginosa (PSA). S. aureus (SA) and PSA are common pathogens causing pneumonia in cystic fibrosis (CF) patients. In this study, the in vitro susceptibilities of DLX and comparator quinolones were determined for clinical isolates from US CF patients collected during 2019-2021. Methods Isolates from CF patients hospitalized with pneumonia were consecutively collected at 17 US medical centers participating in the SENTRY Surveillance Program. Sites submitted 1 isolate per patient per infection episode. Isolate identification was determined at each site and confirmed using MALDI-TOF at JMI Laboratories. Susceptibility testing was performed according to CLSI broth microdilution methodology. FDA interpretive criteria were used for DLX, and CLSI (2022) criteria were applied to comparators. Results A total of 115 SA, including 72 MSSA and 67 PSA, were submitted. Susceptibilities (%S) to DLX, levofloxacin (LEV), and moxifloxacin (MOX) for MSSA are shown in the table. As MOX does not have breakpoints for PSA, ciprofloxacin (CIP) was tested. Against all SA, %S was 73.9%, 67.0%, and 67.0% for DLX, LEV, and MOX, respectively. DLX had the highest %S against MSSA (94.4%). The %S to LEV and MOX was 87.5% and 87.5%. DLX was also more active than comparators against PSA, with DLX 68.7%S, while LEV was 43.3%S and CIP was 50.7%S. Conclusion DLX had good activity against recent CF isolates from US hospitals, and had the highest percent susceptibility of the quinolones tested against MSSA and PSA. These in vitro data suggest that DLX could be a useful therapy when coverage of both MSSA and PSA is needed. Disclosures Dee Shortridge, PhD, AbbVie: Grant/Research Support|JMI Laboratory: Employee|Melinta: Grant/Research Support|Menarini: Grant/Research Support|Shionogi: Grant/Research Support Jennifer M. Streit, BS, MT(ASCP), Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Michael D. Huband, BS, AbbVie: Grant/Research Support|Melinta: Grant/Research Support Mariana Castanheira, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support.

2052. Temporal and Geographical Prevalence of Carbapenem-Resistant Pseudomonas aeruginosa and the In Vitro Activity of Ceftolozane/Tazobactam and Comparators in Taiwan – SMART 2012-2020

Abstract Background Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is listed as a critical pathogen by World Health Organization (WHO). Using clinical isolates collected in Taiwan as part of the global SMART surveillance program, we evaluated the trend of CRPA prevalence in recent nine years (2012-2020) as well as in vitro activity of ceftolozane/tazobactam (C/T) and comparators against CRPA collected from ICU vs non-ICU wards from 2016 to 2020. Methods Between 2012-2020, Pseudomonas aeruginosa (PA) isolates were collected from nine sites in Taiwan (2 in Northern, 3 in Central and 4 in Southern Taiwan). MICs were determined and interpreted based on CLSI broth microdilution guidelines and 2021 CLSI breakpoints. PCR screening and β-lactamase gene sequencing were performed for isolates non-susceptible to imipenem or imipenem/relebactam or C/T. Results During the study period, a total of 2639 PA isolates were collected. Among these, 448 isolates were resistant to either imipenem or meropenem (17.0%). Yearly prevalence rate of CRPA increased from 12.3% in 2012 to 22.8% in 2020: 12.3% in 2012 (14/114), 11.5% in 2013 (16/139), 11.5% in 2014 (13/113), 12.2% in 2015 (41/336), 15.5% in 2016 (57/367), 15.9% in 2017 (68/428), 20.4% in 2018 (73/357), 19.4% in 2019 (75/386) and 22.8% (91/399) in 2020. Hospitals in Northern Taiwan had higher CRPA prevalence rate (22.8%, 131/574) compared to those in Central (15.7%, 126/802) and Southern Taiwan (15.1%, 191/1263). Percentage susceptibility of CRPA isolates to C/T from 2016 to 2020 showed 89.47% (51/57) in 2016, 79.41% (54/68) in 2017, 93.2% (68/73) in 2018, 90.7% (68/75) in 2019 and 98.9% (90/91) in 2020. For ICU vs. Non-ICU CRPA isolates, the susceptibility to C/T were 88.3% vs.93.8%, 77.8% vs. 82.5%, 92.3 % vs. 92.9%, 87.1% vs.93.2% and 100% vs. 98.26%, in 2016,2017, 2018, 2019 and 2020, respectively. Conclusion During the period of 2012-2020, the yearly prevalence of CRPA in Taiwan hospitals increased from 12.3% to 22.8%. The high prevalence and increasing trend of CRPA warrant continuous monitoring of evolving antibiotic resistance in Taiwan. Disclosures Tai-Chin Hsieh, MBBS, MSD Taiwan: Advisor/Consultant|MSD Taiwan: Employee of MSD Taiwan|MSD Taiwan: Stocks/Bonds.

Chemical upcycling of waste PET into sustainable asphalt pavement containing recycled concrete aggregates: Insight into moisture-induced damage

Waste polyethylene terephthalate (PET) plastic and construction and demolition waste are main municipal solid wastes. If they are not properly disposed of, they will cause continuous damage to the ecological environment. Previous studies have shown that recycled concrete aggregate (RCA) can be successfully adopted to replace natural aggregate (NA) for asphalt pavement construction. However, the moisture-induced damage, as one of the pavement engineering performances, is very prominent for asphalt concrete containing RCA (RCA-AC), due to the high absorption of RCA and the weakness of the adhered mortar. Given this, PET additive, derived from waste bottle bodies, is considered to improve the resistance of RCA-AC to moisture-induced damage in this study, which has been previously identified effective to enhance the anti-stripping characteristics of asphalt mixtures containing NA. To achieve this goal, this study applied a series of tests including contact angle, image recognition, boiling water test, immersed Marshall test, freeze–thaw (F-T) splitting test, wheel tracking test, and field emission scanning electron microscope (FESEM) to evaluate the moisture-induced damage of RCA-AC containing PET additive. The results showed that PET additive has a significant ability to improve the bonding strength and adhesion of asphalt binder to RCA and reduce the stripping percentage and moisture-induced susceptibility of RCA-AC, especially under the F-T cycles. In addition, the 60 °C rut deformation resistance of RCA-AC after immersion can be improved as the PET additive is used. Furthermore, the interfacial bonding layers (IBL) of PET additive modified asphalt binder between RCA particles are still existent and its width is not significantly increased after immersion and F-T cycles by contrast to that of virgin binder. In general, the appropriate use of PET additive is a good approach to promote the high-quality recycling of RCA into sustainable asphalt pavement.

P476 Monitoring antifungal resistance in a global collection of Candida spp. surveillance isolates, including C. auris—analysis of resistance in antifungals (ARIA) 2020 study

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PM ObjectivesAnalysis of resistance in antifungals (ARIA) is a recent longitudinal global surveillance initiative collecting yeast and fungal isolates from hospitals worldwide designed to determine susceptibility profiles and monitor the resistance trends among antifungal agents. ARIA reports the susceptibility patterns of data concerning echinocandins, second-generation triazoles, and fluconazole against clinical Candida spp., and filamentous fungal isolates from worldwide sources.Methods Candida spp. isolates (n = 662) were collected from hospitals worldwide during 2020 from 13 different sites—Argentina (n = 1), Australia (n = 2), Germany (n = 1), India (n = 2), Italy (n = 1), Panama (n = 1), Spain (n = 1), Turkey (n = 1), United Kingdom (n = 1), and United States (n = 2). These isolates were shipped to a central laboratory at IHMA Europe, Switzerland, and re-identified by MALDI-TOF or molecular methods. The MICs were performed by broth microdilution method in line with CLSI susceptibility testing standards—CLSI M27-A4 and M38-A2—methodologies and percentage susceptibility (%S) were calculated. Antifungals tested were amphotericin B (AMB), anidulafungin (ANID), fluconazole (FLU), isavuconazole (ISA), caspofungin (CASP), micafungin (MIC), posaconazole (POS), and voriconazole (VOR).ResultsTable 1: Summary MIC and susceptibility data of Candida spp. isolates for all countries combinedConclusionsThe data from the ARIA 2020 study indicate that overall antifungal resistance is low among the Candida spp. isolates except for C. glabrata and C. krusei where resistance to one or more antifungal agents was observed. However, there was no significant difference in susceptibility pattern was observed when susceptibility data of C. glabrata and C. krusei from different continents were compared. The emergence of resistance was evident among C. auris isolates as they have shown reduced susceptibility to azoles in this study.Antifungal resistance surveillance and investigation into resistance mechanisms are of paramount importance. The ongoing ARIA surveillance study will provide resources to monitor antifungal resistance trends, provide key information to caregivers and provide essential information with respect to the development of novel antifungal agents.

P067 Cumulative hospital antibiogram of AIIMS Bhopal for Candida species

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PMObjectives Primary Objectives: To perform the phenotypic identification of the Candida isolates.To perform genotypic identification for confirmation of the Candida species.To prepare antifungal susceptibility profiles of each Candida isolate. Secondary Objectives: To determine the clinical spectrum.To stratify patients based on clinical risk such as per parameters as prior hospitalization and risk for invasive fungal infections.MethodsCross-sectional hospital-based study of 1-year duration 2020-2021. All samples sent to the microbiology laboratory with clinical suspicion of Candida infection and fulfilling the inclusion criteria were considered as sample size for the study period. The study population was the clinically relevant Candida isolates for which antifungal susceptibility testing was done and fulfilling the inclusion criteria. Study duration was for 1-year and was held at AIIMS, Bhopal. The data collected was entered in MS EXCEL and latest WHONET software and analyzed by WHONET software to generate antibiogram for Candida. Results are summarized in percentages and frequencies.ResultsTotal 110 Candida isolates were included in the study for antifungal susceptibility testing and WHONET entry after fulfilling the inclusion criteria.The commonest isolate across all samples processed and included was C. tropicalis 40% followed by C. glabrata 15.5%. A total of 43.6% Candida species were isolated from urine samples followed by 29% from blood samples and 10% from sputum samples. In all 54.5% of yeast isolates were from ICU followed by 40% from ward patients and at least 5.45% from OPD.The commonest isolate across all locations was C. tropicalis 40% followed by C. glabrata 15.5%, C. albicans 14.5% and C. parapsilosis 11.8%. The predominant isolates were under the age category 19-60 years, 69% followed by 26.4% >60 years of age. The percentage susceptibility of C. tropicalis isolates showed >90% susceptibility to tested antifungals. The percentage susceptibility of C. glabrata isolates showed susceptibility to echinocandin but reduced susceptibility to fluconazole. For Candida albicans overall no azole or echinocandin resistance was noted. For Candida parapsilosis overall no azole or echinocandin resistance was noted. C. krusei showed 100% susceptibility to anidulafungin, caspofungin, micafungin, and voriconazole by BMD. C. guilliermondii percentage susceptibility available for caspofungin 33.3%.A total of 80% of the isolates were from patients with community-acquired infections and 19% Candida species were from health care-associated infections. Among the community-acquired infections C. tropicalis was the commonest 37.5% followed by C. albicans 17%, C. glabrata 16%, and C. parapsilosis 12.5%. Among the HAI commonest isolate was C. tropicalis 47.6% followed by 14.3% each of C. auris, and C. glabrata. C. auris all isolates showed elevated MIC fluconazole(≥64 μg/ml), voriconazole (≥1 μg/ml), and caspofungin (≥1 μg/ml).ConclusionThe study conducted just over a year period in the department of microbiology of AIIMS Bhopal has been instrumental in generating cumulative antifungal antibiogram for Candida species.

Comparing the activity of novel antibiotic agents against carbapenem-resistant Enterobacterales clinical isolates.

We compared the activity of 8 novel β-lactam and tetracycline-derivative antibiotics against a cohort of clinical carbapenem-resistant Enterobacterales (CRE) isolates and investigated the incremental susceptibility benefit of the addition of an aminoglycoside, fluoroquinolone, or polymyxin to the β-lactam agents to assist with empiric antibiotic decision making. A collection of consecutive CRE clinical isolates from unique patients at 3 US hospitals (2016-2021) was assembled. Broth microdilution was performed to obtain antimicrobial susceptibility testing results. Mechanisms of carbapenem resistance were investigated through short-read and long-read whole-genome sequencing. Of the 603 CRE isolates, 276 (46%) were carbapenemase producing and 327 (54%) were non-carbapenemase producing, respectively. The organisms most frequently identified were Klebsiella pneumoniae (38%), Enterobacter cloacae complex (26%), and Escherichia coli (16%). We obtained the following percent susceptibility to novel β-lactam agents: ceftazidime-avibactam (95%), meropenem-vaborbactam (92%), imipenem-relebactam (84%), and cefiderocol (92%). Aminoglycosides and the polymyxins provided greater incremental coverage as second agents, compared to fluoroquinolones. Amikacin and plazomicin exhibited the greatest additive value. Ceftazidime-avibactam, meropenem-vaborbactam, and cefiderocol were active against 94% of the 220 KPC-producing isolates. Cefiderocol was active against 83% of the 29 NDM-producing isolates. Ceftazidime-avibactam had 100% activity against the 9 OXA-48-like-producing isolates. Tigecycline had the highest activity compared to other tetracyclines against KPC, NDM, or OXA-48-like-producing isolates. Selection among novel agents requires a nuanced understanding of the molecular epidemiology of CRE. This work provides insights into the comparative activity of novel agents and the additive value of a second antibiotic for empiric antibiotic decision making.

Susceptibility results discrepancy analysis between NHSN Antibiotic Resistance (AR) Option and laboratory instrument data

Background: The NHSN Antibiotic Resistance (AR) Option can serve as a useful tool for tracking antibiotic-resistant infections and can aid in the development of inpatient antibiograms. We recently described the frequency of antibiotic suppression in NHSN AR Option data. In this analysis, we describe the effects of suppression on practical uses of the NHSN AR Option, specifically selected agent antibiogram development, and detection of reportable conditions. Methods: Antibiotic susceptibility data were collected from the NHSN AR Option and commercial automated antimicrobial susceptibility testing instruments (cASTI) from 3 hospital networks. Data were obtained from January 1, 2017, to December 31, 2018. The clinical susceptibility data for third-generation cephalosporins and carbapenems against carbapenem-resistant Enterobacterales (CRE), Pseudomonas aeruginosa, and Acinetobacter baumannii were included. Susceptibility results were defined as suppressed when susceptibility results were observed from the laboratory instrument but not from NHSN data. For the overall percentage susceptibility estimation, isolates with &lt;30 susceptibility results were excluded. Percentage susceptibility of NHSN results were compared to their counterparts from cASTI. Results: Of the 852 matched isolates in the primary analysis, 804 had at least 1 suppressed result. Of the 804 isolates, 16.9% were P. aeruginosa, 67.3% by E. coli, and 11.1% by Klebsiella spp. The following pathogen–drug combinations had no difference observed in the percentage susceptible between the 2 systems: ceftazidime tested against P. aeruginosa, ceftriaxone tested against Klebsiella spp, ertapenem tested against Klebsiella spp, imipenem tested against E. coli and P. aeruginosa, and meropenem tested against P. aeruginosa. Significant differences were observed for the following drugs tested against E. coli: ceftazidime (11.1%), cefotaxime (8.6%), and ceftriaxone (8.3%). In the NHSN AR Option, the following isolates showed suppressed results related to their phenotypic case definition: 17 (3%) CRE isolates, 7 (28%) carbapenem-resistant Acinetobacter baumannii (CRAB) isolates, 511 (93.2%) extended spectrum β-lactamase (ESBL) isolates, and 94 (66.7%) carbapenem-resistant Pseudomonas aeruginosa (CRPA) isolates. Conclusions: For select isolates, notably E. coli, we observed a large difference in the percentage of susceptible isolates reported into the NHSN AR Option compared to the cASTI data. This difference significantly limits the ability of the AR Option to create valid antibiograms for select pathogen–drug combinations. Moreover, significant numbers of CRAB, ESBL, and CRPA isolates would not be identified from NHSN AR Option because of suppression. This finding warrants the need for antimicrobial stewardship teams to regularly assess the impact of selective reporting in identifying pathogens of public health importance.Funding: NoneDisclosures: None

The Combination Antibiogram Evaluation for Antimicrobial Susceptibility of Carbapenem-Resistant Klebsiella pneumoniae and Carbapenem-Resistant Escherichia coli

Background: The incidence of carbapenem-resistant enterobacterales (CRE), Escherichia coli and Klebsiella pneumoniae increased twofold and tenfold within the past 20 years, respectively. CRE is resistant to most antibiotics and monotherapy cannot provide greater than 90% coverage. Combination antimicrobial regimen is introduced to increase the susceptibility rate and to recommend clinicians to make more informed decision in the selection of empirical therapy. Materials and Methods: Cross-sectional study on carbapenem-resistant E. coli and carbapenem-resistant K. pneumoniae isolated from blood, sputum, and urine of adult inpatients in Naresuan University Hospital were examined for 24 months, between January 1, 2018 and December 31, 2019. The susceptibility data were formulated in accordance with the Clinical and Laboratory Standards Institute M39 guidelines and the combination antibiogram was developed. Chi-square test and Fisher’s exact test were used to determine the differences in susceptibility rates. Results: Forty-three isolates of the carbapenem-resistant E. coli and 208 isolates of the carbapenem-resistant K. pneumoniae were included for the analysis. More CRE organisms were found in the Internal Medicine than in the non-Internal Medicine wards. Monotherapy regimen with amikacin was shown to cover 97.67% of the E. coli CRE in vitro and when used as an additional agent as meropenem plus amikacin, imipenem plus amikacin, piperacillin-tazobactam plus amikacin, or levofloxacin plus amikacin, which all the percent susceptible increased to 97.67% (p&lt;0.001). The K. pneumoniae CRE data showed that only 1.92% was susceptible to meropenem. Meropenem plus gentamicin, imipenem plus gentamicin, piperacillin-tazobactam plus gentamicin and levofloxacin plus gentamicin could increase the percent susceptibility but to less than 90% with p&lt;0.001. Conclusion: Aminoglycosides are the proposed addition for the empiric antimicrobial combination therapy to treat possible CRE infections. Meropenem plus amikacin, imipenem plus amikacin, piperacillin-tazobactam plus amikacin, or levofloxacin plus amikacin are proposed to use against E. coli CRE. No combination therapy is recommended for K. pneumoniae CRE. Keywords: Enterobacteriaceae; Carbapenem-resistant Klebsiella pneumoniae; Carbapenem-resistant Escherichia coli; CRE; Antimicrobial susceptibility; Combination antibiogram