Complicated Intra-abdominal Infections Research Articles

Antimicrobial and Microbiological Characteristics of Critically Ill Patients with Complicated Intra-Abdominal Infection: Observational Data from Beth Israel Deaconess Medical Center.

PurposeWe describe the clinical characteristics, isolated microorganisms and antibiotics used in patients with cIAIs during ICU stay.MethodsA retrospective analysis of data from Beth Israel Deaconess Medical Center was performed.ResultsA total of 316 patients with cIAIs were included, 57.0% of them were male and the median age was 63 years. A total of 239 patients did have cultures taken, and 74 patients had a positive microbial result. The main pathogens were Escherichia coli, Staphylococci (coagulase negative), Enterococcus sp. and Bacteroides fragilis. The main antibiotics given were vancomycin, metronidazole, piperacillin tazobactam and ciprofloxacin. Univariable and multivariable Cox regression analyses showed that receiving more antibiotics reduced ICU mortality, but the same results were not obtained in the analysis of hospital mortality.ConclusionThe main Gram-positive microorganisms for empirical antimicrobial therapy were Staphylococci (coagulase negative), Enterococcus sp. and Staphylococcus aureus, and Gram-negative microorganisms were Escherichia coli, Bacteroides fragilis and Klebsiella pneumoniae. The use of more antibiotics reduced ICU mortality, but the same results were not obtained in the analysis of hospital mortality.

Comparative Analysis of Short-Course Vs Long Course Antibiotic Therapy among Patients with Complicated Intra-Abdominal Infections

Background: Complicated intra-abdominal infections have become a major health challenge that merits safe and efficacious therapy. Antibiotic therapy is the treatment of choice, however the duration of antibiotic use is debatable.
 Objective: To compare the safety and efficacy of the short course and long course antibiotic therapy towards the treatment and the progressive outcome of patients presented with complicated intra-abdominal infections.
 Methodology: This comparative study was carried out on 94 subjects (chosen via non-probability, consecutive sampling), who presented with complicated intra-abdominal infections, had signs and symptoms of infection along with ultrasound abdomen examination consistent with infective foci and routine blood test showing raised total leukocyte count, at the Department of Surgery - Liaquat University Hospital, Hyderabad. Subjects were divided into two groups (47 in each) through a random assignments. Group-A was kept on a short course (5-7-days) while Group-B was kept on a long course (7-10 days) antibiotic therapy. Data were documented using a structured questionnaire, including inquiries related to sociodemographic details, disease specifics, and observed for the outcome variables (mainly postoperative early resolution of infection and long hospital stay).
 Results: In Group A, resolution of infection was achieved in 59.57%, 29.79% and 10.64% patients on day 5, 6 and 7, espectively. In Group B, esoluation of infection was only reported as 42.55%, 36.17% and 21.28% on day 5, 6 and 7, respectively. The median duration of taking antibiotic was almost half in short course group than the long. Surgical site infections were commonly observed in Group B patients. There was no mortality observed in both groups. There is no significance difference observed in primary outcome of clinical cure among the groups.
 Conclusion: It can be concluded that the short course antibiotic therapy has good efficacy to treat CIAI when the primary foci of infection are surgically extracted with adequate source control.

Non-susceptibilities to antibiotics against important Gram-negative bacteria, and imipenem-relebactam, meropenem-vaborbactam against carbapenem non-susceptible Enterobacterales and Pseudomonas aeruginosa isolates implicated in complicated intra-abdominal and urinary tract infections in Taiwan, 2019

Susceptibility of isolates of top-ranking Enterobacterales species and Pseudomonas aeruginosa implicated in complicated intra-abdominal infections (cIAI) and urinary tract infections (cUTI) to important antibiotics, including imipenem-relebactam (IMR) and meropenem-vaborbactam (MVB), in Taiwan in 2019 were evaluated. MICs to various antibiotics were determined using broth microdilution method. Susceptibility results were interpreted mainly based on the MIC breakpoints of the Clinical and Laboratory Standards Institute (CLSI) 2021, but susceptibilities of IMR and MVB were interpreted based on the CLSI and European Committee on Antimicrobial Susceptibility Testing (EUCAST) 2021. Resistance genes amongst carbapenem-non-susceptible (NS) Gram-negative bacteria (GNB) were investigated using multiplex polymerase chain reaction (PCR). Escherichia coli (n=356), Klebsiella pneumoniae (n=165) and Enterobacter cloacae complex (n=42) isolates accounted for 85.3% of the 660 Enterobacterales isolates. The non-susceptibility rates of imipenem (IPM), IMR against isolates of non-Morganellaceae Enterobacterales, and meropenem (MEM), MVB against all Enterobacterales isolates were 92.2%/94.8%, 98.4-98.7%/98.4-99%, 95%/98.2% and 98.8-100%/99.4-100% for the cIAI/cUTI subgroups, respectively. Amongst the 40 IPM-NS-non-Morganellaceae Enterobacterales isolates, when the CLSI 2021 criteria were applied, 10 were NS to IMR, and four Klebsiella pneumoniae isolates (harbouring blaKPC but neither blaMBL nor blaOXA-48-like genes) were NS to IMR and MVB. Amongst the 93 Pseudomonas aeruginosa isolates under evaluation, the addition of relebactam (4mg/L) resulted in a 4-to-16-fold reduction in the MICs of IPM in all 15 IPM-NS-Pseudomonas aeruginosa isolates (including 10 porin-deficient ones) not harbouring blaMBL/blaOXA-48-like genes. Contrastingly, the addition of vaborbactam (8mg/L) improved the non-susceptibility to MEM in one (20%) of five IPM/MEM-NS Pseudomonas aeruginosa isolates. Continuous monitoring of susceptibility to clinically important GNB is warranted.

Retrospective Cohort Analysis of the Effect of Antimicrobial Stewardship on Postoperative Antibiotic Therapy in Complicated Intra-Abdominal Infections: Short-Course Therapy Does Not Compromise Patients’ Safety

Background: Recent evidence suggests that short-course postoperative antibiotic therapy (PAT) of intra-abdominal infections is non-inferior considering clinical outcomes. The aim of this study was to compare the outcome of short vs. long PAT in complicated intra-abdominal infections (cIAIs) without sepsis. Methods: We performed a single center-quality improvement study at a 1500 bed sized university hospital in Bavaria, Germany, with evaluation of the length of antibiotic therapy after emergency surgery on cIAIs with adequate source control during 2016 to 2018. We reviewed a total of 260 cases (160 short duration vs. 100 long duration). The antibiotic prescribing quality was assessed by our in-house antimicrobial stewardship team (AMS). Results: No significant differences of patient characteristics were observed between short and long PAT. The frequency of long PAT declined during the observation period from 48.1% to 26.3%. Prolongation of PAT was not linked with any clinical benefits, on the contrary clinical outcome of patients receiving longer regimes were associated with higher postoperative morbidity. AMS identified additional educational targets to improve antibiotic prescribing quality on general wards like unnecessary postoperative switches of antibiotic regimes, e.g., unrequired switches to oral antibiotics as well as prolongation of PAT due to elevated CRP. Conclusion: Short-course antibiotic therapy after successful surgical source control in cIAIs is safe, and long-duration PAT has no beneficial effects.

POSA122 Budget Impact Analysis of Introducing Ceftolozane/Tazobactam Injection for Treatment of Complicated Intra-Abdominal Infections and Complicated Urinary Tract Infections in the Ministry of Health Malaysia Facilities

Growing prevalence of multidrug-resistant (MDR) pathogens is a major problem specifically in cases of complicated intra-abdominal infections (cIAIs) and complicated urinary tract infections (cUTIs) associated with increasing mortality, morbidity and healthcare costs leading to the need of new effective and safe treatment options. The aim of this study is to estimate the budget impact (BI) of introducing Ceftolozane/Tazobactam as treatment of cIAIs and cUTIs in public facilities under Ministry of Health Malaysia (MoHM).

1154. Safety and Efficacy of Ceftolozane/Tazobactam Plus Metronidazole Versus Meropenem in Pediatric Participants With Complicated Intra-abdominal Infection: A Phase 2, Randomized Clinical Trial

BackgroundCeftolozane/tazobactam (C/T), a cephalosporin–β-lactamase inhibitor combination, is approved for treatment of complicated urinary tract infections, complicated intra-abdominal infections (cIAI), and nosocomial pneumonia in adults. Safety and efficacy of C/T in pediatric participants with cIAI was assessed.MethodsThis phase 2 study (NCT03217136) compared C/T + metronidazole (MTZ) with meropenem (MEM) for treatment of cIAI. Age- and weight-adjusted dosing is summarized in Table 1. The primary objective was to evaluate the safety and tolerability of C/T + MTZ compared with MEM. A key secondary endpoint was clinical cure at end of treatment (EOT) and test of cure (TOC).Table 1. Summary of Dosing and Pharmacokinetic Sampling Schedule by Age Cohort ResultsA total of 94 participants were randomized 3:1; 91 were treated with C/T + MTZ (n=70) or MEM (n=21) comprising the modified intent-to-treat (MITT) population. The clinically evaluable population included 78 participants at EOT (C/T + MTZ, n=59; MEM, n=19) and 77 participants at TOC (C/T + MTZ, n=58; MEM, n=19). The most common diagnosis and pathogen in the MITT population were complicated appendicitis (C/T + MTZ, 91.4%; MEM, 100%) and Escherichia coli (C/T + MTZ, 67.1%; MEM, 61.9%). The mean (SD) intravenous therapy/overall treatment duration was 6.4 (2.8)/9.3 (3.6) days and 5.8 (1.8)/9.0 (3.2) days for C/T + MTZ and MEM, respectively. In total, ≥1 adverse events (AE) occurred in 80.0% and 61.9% of participants receiving C/T + MTZ and MEM, respectively (Table 2), of which 18.6% and 14.3% were considered drug related. Serious AE occurred in 11.4% (8/70) and 0% (0/21) of participants receiving C/T + MTZ and MEM, respectively; none were considered drug related. No drug-related study drug discontinuations occurred. In the MITT population, rates of clinical cure for C/T + MTZ and MEM at EOT were 80.0% and 95.2%, and at TOC were 80.0% and 100%, respectively (Figure 1); 6 of the 14 failures for C/T + MTZ were indeterminate responses scored as endpoint failures per protocol. In the clinically evaluable (CE) population, rates of clinical cure for C/T + MTZ and MEM were 89.8% and 100% at EOT, and 89.7% and 100% at TOC, respectively (Figure 1). ConclusionC/T + MTZ was well tolerated in pediatric participants with cIAI, and rates of clinical success were high with C/T treatment. C/T is a promising new treatment option for children with cIAI.Disclosures Carl-Christian A. Jackson, MD, Merck & Co. Inc. (Shareholder) Julia Lonchar, MSc, Merck Sharp & Dohme Corp. (Employee, Shareholder) Feng-Hsiu Su, MPH, MBA, Merck Sharp & Dohme Corp. (Employee, Shareholder) Jennifer A. Huntington, PharmD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee) Mekki Bensaci, PhD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee) Myra W. Popejoy, PharmD, Merck Sharp & Dohme Corp. (Employee) Matthew G. Johnson, MD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee) Carisa S. De Anda, PharmD, Merck Sharp & Dohme Corp. (Employee, Shareholder) Elizabeth G. Rhee, MD, Merck Sharp & Dohme Corp (Employee, Shareholder) Christopher Bruno, MD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee)

1273. Activity of Ceftolozane/Tazobactam and Comparators Against Enterobacterales and P. aeruginosa Isolates from Pediatric Patients—SMART United States 2017-2019

BackgroundCeftolozane/tazobactam (C/T) is an antipseudomonal cephalosporin combined with a β-lactamase inhibitor approved by FDA and EMA for complicated urinary tract (cUTI) and complicated intraabdominal infections (cIAI), as well as hospital-acquired/ventilator-associated bacterial pneumonia (HABP/VABP) in patients ≥18 years. Clinical trials studying the use of C/T for pediatric patients with cUTI and cIAI are completed, and HABP/VABP pediatric studies are underway. We evaluated the antimicrobial activity of C/T against gram-negative isolates collected from patients ≤17 years in the United States (US) as part of the global SMART surveillance program.MethodsIn 2017-2019, 27 US clinical labs each collected up to 250 consecutive gram-negative pathogens per year. A total of 1336 isolates were collected from pediatric patients. MICs were determined using CLSI broth microdilution and breakpoints. C/T-nonsusceptible Enterobacterales (Ebact) and P. aeruginosa were screened for genes encoding β-lactamases.ResultsAmong the 944 collected Ebact and 220 P. aeruginosa isolates, 40.7% and 76.4%, respectively, were collected from patients with respiratory tract infections, 37.0% and 10.0% from UTI, 13.7% and 8.2% from IAI, and 8.3% and 5.0% from bloodstream infections. The table shows antimicrobial susceptibility of Ebact, P. aeruginosa, and select phenotypes. C/T was active against 98% of Ebact, including 50 of 51 and 12 of 13 ESBL-non-CRE phenotype E. coli and K. pneumoniae, respectively. Among P. aeruginosa, C/T was active against 95% of isolates, 9-21 percentage points higher than the comparator β-lactams, and it maintained activity against 71-75% of P. aeruginosa isolates nonsusceptible to commonly used β-lactams. Among the 21 C/T-nonsusceptible Ebact, 2 isolates carried KPC and ESBL and 3 isolates carried only ESBL; in 16 isolates no β-lactamases were detected, of which 15 were species with intrinsic AmpC. Among 12 C/T-nonsusceptible P. aeruginosa, no acquired β-lactamases were detected, likely indicating chromosomally-mediated resistance mechanisms.Results Table ConclusionC/T could be a potential new treatment option for US pediatric patients with infections caused by Ebact and P. aeruginosa, including resistant phenotypes.Disclosures Sibylle Lob, PhD, IHMA (Employee)Pfizer, Inc. (Independent Contractor) Meredith Hackel, PhD MPH, IHMA (Employee)Pfizer, Inc. (Independent Contractor) C. Andrew DeRyke, PharmD, Merck & Co., Inc. (Employee, Shareholder) Kelly Harris, PharmD, BCPS, Merck & Co. Inc (Employee) Katherine Young, MS, Merck (Employee) Mary Motyl, PhD, Merck & Co., Inc. (Employee, Shareholder) Daniel F. Sahm, PhD, IHMA (Employee)Pfizer, Inc. (Independent Contractor)

1159. Pharmacokinetics, Safety, and Tolerability of Imipenem/Cilastatin/Relebactam in Pediatric Participants With Confirmed or Suspected Gram-negative Bacterial Infections: A Phase 1b, Open-label, Single-Dose Clinical Trial

BackgroundImipenem/cilastatin/relebactam (IMI/REL) is approved for treating hospital-acquired/ventilator-associated bacterial pneumonia, complicated urinary tract infection, and complicated intra-abdominal infection in adults. This study assessed single-dose pharmacokinetics (PK), safety, and tolerability of IMI/REL in neonatal and pediatric participants with confirmed or suspected gram-negative bacterial infections.MethodsThis was a phase 1, open-label, non-comparative study (NCT03230916). Age- and weight-adjusted dosing is summarized in Table 1. The primary objective was to characterize the PK profiles for imipenem and relebactam after a single intravenous dose of IMI/REL. PK parameters were analyzed using population modeling. The PK target for imipenem was the percent time of the dosing interval that the unbound plasma concentration exceeded the minimum inhibitory concentration (%fT >MIC) of ≥30% (MIC used, 2 µg/mL). The PK target for relebactam was an area under the curve (AUC)/MIC ratio >8 (MIC used, 2 µg/mL), corresponding to AUC0-24h >58.88 μM∙h. Safety and tolerability were assessed for up to 14 days after drug infusion. ResultsOf the 46 participants who received IMI/REL, 42 were included in the PK analysis. The mean plasma concentration-time profiles for imipenem and relebactam were generally comparable across age cohorts (Figure). For imipenem, the geometric mean %ƒT >MIC ranged from 50% to 94% and the mean maximum concentration (Cmax) ranged from 65 μM to 126 μM (Table 2). For relebactam, the geometric Cmax ranged from 33 μM to 87 μM and mean AUC0-6h ranged from 51 μM·h to 159 μM·h across the age cohorts (Table 2). IMI/REL was well tolerated with 8 (17.4%) participants experiencing ≥1 adverse events (AE) and 2 (4.3%) participants experiencing AE that were deemed drug related by the investigator. Drug-related AE were increased alanine aminotransferase, increased aspartate aminotransferase, anemia, and diarrhea, which were non-serious, mild in severity, and resolved within the follow-up period of 14 days.Figure 1 ConclusionImipenem and relebactam exceeded the pediatric plasma PK targets across pediatric age cohorts in the study; the single doses of IMI/REL were well tolerated. These results will inform IMI/REL dose selection for further pediatric clinical evaluation.Disclosures Camilla Tøndel, MD, PhD, Merck & Co., Inc., (Grant/Research Support) Emmanuel Roilides, MD, PhD, FIDSA, FAAM, FESCMID, FECMM, FISAC, Merck Sharp & Dohme Corp. (Consultant, Grant/Research Support) Matthew S. Kelly, MD, MPH, Merck Sharp & Dohme Corp. (Consultant, Grant/Research Support) Munjal Patel, PhD, Merck Sharp & Dohme Corp. (Employee, Shareholder) Pavan Vaddady, PhD, Merck Sharp & Dohme Corp. (Employee) Alok Maniar, MD, MPH, Merck Sharp & Dohme Corp. (Employee, Shareholder) Ying Zhang, PhD, Merck & Co., Inc. (Employee, Shareholder) Amanda Paschke, MD MSCE, Merck Sharp & Dohme Corp. (Employee, Shareholder) Joan R. Butterton, MD, Merck Sharp & Dohme Corp. (Employee, Shareholder) Luke F. Chen, MBBS MPH MBA FRACP FSHEA FIDSA, Merck (Employee)

1080. Relebactam Increases Imipenem Activity Against Imipenem-Nonsusceptible and -Susceptible Pseudomonas aeruginosa and Enterobacterales: Assessment of Isolates from RESTORE-IMI 2

BackgroundRelebactam (REL) inhibits class A and C β-lactamases (BLs) and is approved in the US in the combination imipenem/cilastatin/REL (IMI/REL) for hospital acquired bacterial pneumonia (HABP) and ventilator associated bacterial pneumonia (VABP), and also in patients with limited treatment options for complicated urinary tract infections and complicated intraabdominal infections. The objective of this study was to evaluate the potentiation of imipenem (IMI) by REL in baseline respiratory isolates from the recently completed Phase 3 RESTORE-IMI 2 study that demonstrated efficacy and safety of IMI/REL in the treatment of patients with HABP/VABP.MethodsBaseline lower respiratory tract (LRT) isolates were evaluated for IMI MICs in the presence and absence of REL using broth microdilution and CLSI interpretive criteria. All Pseudomonas aeruginosa and Enterobacterales for which IMI/REL is either indicated or the MIC90 is less than or equal to the susceptibility breakpoint were evaluated.ResultsSummary statistics and the MIC distribution for P. aeruginosa are shown in the figure. For P. aeruginosa, REL reduces the IMI mode MIC of IMI-nonsusceptible (IMI-NS) (MIC >2) isolates ≥8-fold (from 16-32 to 2 µg/mL) and that of IMI-susceptible (IMI-S) (MIC ≤2) isolates ≥2-fold (from 1 to ≤0.5 µg/mL). Among Enterobacterales, the IMI mode MIC of IMI-NS (MIC >1) isolates was reduced ≥4-fold (from 2 to ≤0.5 µg/mL). REL enhanced the activity of IMI among IMI-S isolates (MIC ≤1), most notably observed in Enterobacterales species that produce a chromosomal AmpC, increasing the proportion with MIC ≤0.5 µg/mL from 76% to 98%.MIC Distribution and Summary Statistics of RESTORE IMI-2 Isolates ConclusionAmong baseline LRT isolates from RESTORE-IMI 2 the potentiation of IMI by REL results in the restoration of susceptibility among IMI-NS P. aeruginosa and Enterobacterales and enhanced IMI activity among IMI-S isolates. This enhanced activity among IMI-S Enterobacterales is most notable among species with reported chromosomal expression of AmpC. This lowering of IMI MICs upon addition of REL contributes to the high probability of target attainment (≥90%) observed following administration of IMI/REL 1.25g every 6 hours, further supporting the IMI/REL efficacy data observed in RESTORE-IMI 2.Disclosures David W. Hilbert, PhD, Merck (Employee) C. Andrew DeRyke, PharmD, Merck & Co., Inc. (Employee, Shareholder) Maria C. Losada, BA, Merck (Employee) Pamela Moise, PharmD, Merck (Employee) Luke F. Chen, MBBS MPH MBA FRACP FSHEA FIDSA, Merck (Employee) Katherine Young, MS, Merck (Employee)

1290. Ceftazidime-Avibactam Resistance Report in a Third Level Hospital in Mexico City

BackgroundThe surge of resistant Gram-negative organisms has been worrying infectious disease physicians and physicians in general because of the lack of a large number of antibiotics to which these organisms remain susceptible. Ceftazidime-Avibactam (CAZ-AVI) is a drug approved by the FDA to treat complicated urinary tract infections (cUTI), complicated intra-abdominal infections (cIAIs) in combination with metronidazole, and recently for the treatment of nosocomial pneumonia. Worldwide resistance rates of Enterobacteriaceae to CAZ-AVI have been reported below 2.6%, and 4-8% for Pseudomonas aeruginosa. The FDA, CLSI, and EUCAST assigned the clinical breakpoints of susceptibility: MIC < /=8 mg/liter susceptible, and >/=8mg/liter, resistant. In Mexico, CAZ-AVI was approved in 2018, and its cost is very high compared to other antimicrobials, so its use is limited in very specific cases. The resistance rates to this antibiotic in the Mexican population remain largely unknown. MethodsWe tested 106 specimens for susceptibility to ceftazidime-avibactam using the disk Kirby-Bauer method. The inhibition zone diameter was determined in all cases and we considered the organism susceptible when the inhibition zone diameter was >=21 mm, and resistant with an inhibition zone diameter < = 20 mm. ResultsWe found 5 specimens (4.71%) resistant to ceftazidime-avibactam, corresponding to E. coli (3) and P. aeruginosa (2). Two of these were also resistant to colistin, and 4 to meropenem. All carbapenem-resistant isolates harbored Metallo-beta-lactamases genes, for E. coli was NDM gen, and for P. aeruginosa the VIM gene(GeneXpert® Cepheid). ConclusionThe ceftazidime-avibactam resistance among Gram-negative bacteria in our study is similar to the one reported in other international studies. We need more studies in our population to know the nationwide resistance to this antibiotic. Disclosures All Authors: No reported disclosures

1143. Safety and Efficacy of Ceftolozane/Tazobactam Versus Meropenem in Neonatal and Pediatric Participants With Complicated Urinary Tract Infection, Including Pyelonephritis: A Phase 2, Randomized, Clinical Trial

BackgroundCeftolozane/tazobactam (C/T) is a cephalosporin–β-lactamase inhibitor combination approved to treat complicated urinary tract infections (cUTI), complicated intra-abdominal infections, and nosocomial pneumonia in adults. Safety and efficacy of C/T in neonatal and pediatric participants with cUTI was assessed.MethodsThis phase 2, randomized, double-blind study (NCT03230838) compared C/T with meropenem (MEM) for treatment of cUTI, including pyelonephritis in participants from birth to 18 years of age. Treatment duration was 7-14 days. After 3 days of intravenous therapy, optional oral step-down therapy was allowed. Participants were stratified and dosed by age group (Table 1). The primary objective was to evaluate the safety and tolerability of C/T compared with MEM, and key secondary end points included clinical response and per-participant microbiologic response at end of treatment (EOT) and test of cure (TOC). ResultsParticipants were randomized 3:1 and treated with C/T (n=100) or MEM (n=33). The microbiologic modified intent-to-treat population (mMITT) included 95 participants in the C/T (n=71) and MEM (n=24) arms; the most common reason for mMITT exclusion was lack of a qualifying baseline uropathogen (28.4%). Pyelonephritis was the most common baseline diagnosis (83.2%), and Escherichia coli was the most common qualifying baseline uropathogen (77.9%). Overall mean treatment duration was comparable in both arms (C/T, 10.2 days; MEM, 10.7); a total of 50 (70.4%) and 20 (83.3%) participants switched to optional oral step-down therapy in the C/T and MEM arms, respectively, both for a mean of approximately 6 days. The overall incidence of adverse events (AE; all and drug related), serious AE (SAE), and AE leading to discontinuation was comparable between C/T and MEM arms. There were no AE leading to death, drug-related SAE, or discontinuations due to drug-related AE or SAE (Table 2). For C/T and MEM, rates of clinical cure and microbiologic eradication at EOT and TOC were high (Figure). ConclusionIn this study, C/T was well tolerated with a safety profile comparable to MEM and to the previously reported safety profile for C/T in adults with cUTI. C/T achieved high clinical cure and microbiologic eradication rates and is a potential new treatment option for children with cUTI.Disclosures Emmanuel Roilides, MD, PhD, FIDSA, FAAM, FESCMID, Merck Sharp & Dohme Corp. (Consultant, Grant/Research Support) Negar Ashouri, MD, Merck Sharp & Dohme Corp. (Grant/Research Support) Matthew G. Johnson, MD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee) Julia Lonchar, MSc, Merck Sharp & Dohme Corp. (Employee, Shareholder) Feng-Hsiu Su, MPH, MBA, Merck Sharp & Dohme Corp. (Employee, Shareholder) Jennifer A. Huntington, PharmD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee) Myra W. Popejoy, PharmD, Merck Sharp & Dohme Corp. (Employee) Mekki Bensaci, PhD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee) Carisa S. De Anda, PharmD, Merck Sharp & Dohme Corp. (Employee, Shareholder) Elizabeth G. Rhee, MD, Merck Sharp & Dohme Corp (Employee, Shareholder) Christopher Bruno, MD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee)

1295. Susceptibility to Ceftolozane/Tazobactam and Comparators Among Pseudomonas aeruginosa Isolates Collected from Patients in Hospitals in Latin America – SMART 2017-2019

Abstract Background Ceftolozane is a cephalosporin specifically developed to have enhanced antibacterial activity against P. aeruginosa. Combined with tazobactam, it was approved by FDA and EMA for complicated urinary tract and intraabdominal infections, as well as hospital-acquired/ventilator-associated bacterial pneumonia. We evaluated the activity of ceftolozane/tazobactam (C/T) against P. aeruginosa isolates collected as part of the global SMART surveillance program in 10 countries in Latin America. Methods In 2017-2019, 41 clinical labs each collected up to 250 consecutive gram-negative pathogens per year from various infection sources. A total of 21,864 isolates were collected, of which 3,335 (15.3%) were P. aeruginosa. MICs were determined using CLSI broth microdilution and breakpoints. C/T-nonsusceptible (NS) P. aeruginosa isolates were screened for genes encoding β-lactamases. Results The table shows the antimicrobial susceptibility of P. aeruginosa and β-lactam-NS subsets. C/T was active against 85.9% of all collected P. aeruginosa, with lowest activity against isolates collected in Chile and Venezuela, where 28.0% and 23.2% of isolates, respectively, carried carbapenemases, and highest activity against isolates from Ecuador and Guatemala, where 2.2% and 4.2%, respectively, were carbapenemase-positive. Substantial variability in the activity of C/T and comparators was observed among β-lactam-NS subsets. In aggregate, however, C/T remained active against 59.9% of all meropenem-NS P. aeruginosa isolates from Latin America (n=1,101), 57.3% of piperacillin/tazobactam-NS isolates (n=1054), 48.9% of cefepime-NS isolates (n=895), and 50.3% of ceftazidime-NS isolates (n=937). Conversely, other common β-lactams (meropenem, cefepime, ceftazidime, and piperacillin/tazobactam) remained active against 8-38% of these resistant isolates. Results Table Conclusion C/T showed the highest activity against P. aeruginosa among the tested β-lactam antibiotics. While amikacin showed similar or better activity in vitro, its toxicities severely limit its clinical use. Given the desirability of β-lactams among clinicians, C/T represents an important option in the treatment of infections caused by P. aeruginosa in Latin America. Disclosures Sibylle Lob, PhD, IHMA (Employee)Pfizer, Inc. (Independent Contractor) Meredith Hackel, PhD MPH, IHMA (Employee)Pfizer, Inc. (Independent Contractor) C. Andrew DeRyke, PharmD, Merck &amp; Co., Inc. (Employee, Shareholder) Jacquleine Pavía, MSc, Merck &amp; Co, Inc (Employee) Fakhar Siddiqui, PhD, Merck &amp; Co, Inc (Employee) Katherine Young, MS, Merck (Employee) Mary Motyl, PhD, Merck &amp; Co., Inc. (Employee, Shareholder) Daniel F. Sahm, PhD, IHMA (Employee)Pfizer, Inc. (Independent Contractor)

1274. Activity of Ceftolozane/Tazobactam, Imipenem/Relebactam, and Comparators Against Pseudomonas aeruginosa Isolates from Patients with Bloodstream and Other Infection Types—SMART United States/Canada 2018-2019

BackgroundCeftolozane/tazobactam (C/T), an antipseudomonal cephalosporin combined with a β-lactamase inhibitor, was approved for treatment of complicated urinary tract (cUTI) and intraabdominal infections (cIAI), and hospital-acquired/ventilator-associated bacterial pneumonia (HAP/VAP). Imipenem/relebactam (IMI/REL) is a combination of imipenem/cilastatin with relebactam, an inhibitor of class A and C β-lactamases. IMI/REL was approved for HAP/VAP and for infections due to aerobic gram-negative organisms in adults with limited treatment options (e.g., cUTI, cIAI). We compared the activity of C/T and IMI/REL against P. aeruginosa from bloodstream infections (BSI) to those from other infection types.MethodsAs part of the SMART program, 24 hospitals in the US and 8 in Canada each collected up to 250 consecutive gram-negative isolates per year in 2018-2019 from patients with BSI, lower respiratory tract infections (LRTI), IAI, and UTI. A total of 2351 Pa isolates were collected. MICs were determined using CLSI broth microdilution and breakpoints.Results Pa isolates from BSI tended to show higher susceptibility than IAI, UTI, and especially LRTI isolates (Table). Susceptibility to the tested comparator β-lactams was 11-12 percentage points lower among LRTI than BSI isolates, while C/T and IMI/REL susceptibility was only 2-5% lower. Even among BSI isolates, the comparator β-lactams were active against only 75-88% of isolates, while C/T and IMI/REL were active against >95%. Only amikacin showed higher activity. Analyzing coverage by either C/T or IMI/REL, 98.7% of Pa isolates from BSI were susceptible to one or both agents. C/T and IMI/REL maintained activity against 89% and 69% of meropenem-nonsusceptible (MEM-NS) Pa isolates from BSI (n=36), respectively, and 87% and 76% of piperacillin/tazobactam (P/T)-NS Pa (n=38).Results Table ConclusionEven among BSI isolates, which were generally more susceptible than those from other infection types, Pa susceptibility to commonly used β-lactams like MEM and P/T was < 90%, 7-23% lower than C/T and IMI/REL. Given the desirability of β-lactams among clinicians and the >98% coverage by either C/T or IMI/REL of Pa isolates from BSI, both agents represent important options in the treatment of patients with BSI.Disclosures Sibylle Lob, PhD, IHMA (Employee)Pfizer, Inc. (Independent Contractor) Meredith Hackel, PhD MPH, IHMA (Employee)Pfizer, Inc. (Independent Contractor) C. Andrew DeRyke, PharmD, Merck & Co., Inc. (Employee, Shareholder) Kelly Harris, PharmD, BCPS, Merck & Co. Inc (Employee) Katherine Young, MS, Merck (Employee) Mary Motyl, PhD, Merck & Co., Inc. (Employee, Shareholder) Daniel F. Sahm, PhD, IHMA (Employee)Pfizer, Inc. (Independent Contractor)

110. A Phase 3, Multicenter, Double-blind, Randomized Clinical Trial to Evaluate the Efficacy and Safety of Ceftolozane/Tazobactam Plus Metronidazole Versus Meropenem in Chinese Participants With Complicated Intra-abdominal Infections

BackgroundIn China, the prevalence of infections due to multidrug-resistant gram-negative bacteria is high and additional treatment options for complicated intra-abdominal infections (cIAI) are needed. This study compared the efficacy and safety of ceftolozane/tazobactam (C/T) + metronidazole (MTZ) versus meropenem (MEM) + placebo (pbo) for the treatment of cIAI in adult Chinese participants.MethodsThis was a phase 3, double-blind study conducted at 21 centers in China (NCT03830333). Participants aged 18-75 years with cIAI requiring surgical intervention within 24 hours of study drug administration were stratified by site of infection and randomized 1:1 to receive 1.5 g C/T (1 g ceftolozane and 0.5 g tazobactam) + 0.5 g MTZ administered intravenously (IV) every 8 hours (q8h) or 1 g MEM + pbo administered IV q8h for 4-14 days. The primary endpoint was clinical cure at test of cure (TOC) in the clinically evaluable (CE) population. Secondary endpoints included rates of clinical cure, per-participant microbiologic response, per-pathogen microbiologic response, and adverse events (AE). Non-inferiority for clinical cure at TOC in the CE population was confirmed if the lower bound of the 2-sided 95% CI for the between-treatment difference in the clinical cure rate was larger than −12.5%.ResultsA total of 134 participants were randomized to each treatment group. Demographics and baseline characteristics were generally well balanced between treatment groups (Table 1). The median (range) age in the ITT population was 50 (18-75) years and 61% were men. The most frequent sites of infection were the appendix (C/T + MTZ, 50.0%; MEM + pbo, 49.3%) and gallbladder (C/T + MTZ, 27.6%; MEM + pbo, 29.1%). Overall, the most frequently isolated pathogens were Escherichia coli (61.4%) and Klebsiella pneumoniae (17.3%); few anaerobes were isolated (Table 1). C/T + MTZ was non-inferior to MEM + pbo for clinical cure in the CE population (C/T + MTZ, 95.2%; MEM + pbo, 93.1%; difference, 2.1% [95% CI, −4.7% to 8.8%]). Results for key secondary endpoints were comparable between treatment groups (Table 2). Rates of AEs were generally similar between treatment groups (Table 3). ConclusionC/T + MTZ was non-inferior to MEM + pbo in the treatment of adult Chinese participants with cIAI and demonstrated a favorable safety profile.Disclosures Xiaofei Chen, n/a, MSD, China (Employee) Xiaoling Du, n/a, MSD, China (Employee) Ye Wang, n/a, MSD, China (Employee) Hui Wang, n/a, MSD, China (Employee) Fang Sun, n/a, MSD, China (Employee) Matthew G. Johnson, MD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee) Mekki Bensaci, PhD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee) Jennifer A. Huntington, PharmD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee) Christopher Bruno, MD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee)

1243. Eravacycline in Bacteremia: A Case Series

BackgroundEravacycline (ERV) is FDA-approved for the treatment of complicated intra-abdominal infections, but there is limited experience for non-FDA approved indications. MethodsWe present five cases that utilized ERV for treatment of bacteremia.ResultsPatient 1 in septic shock (SS) started on vancomycin (VAN) and ceftazidime-avibactam (CZA). Blood culture (BC) finalized to E. coli and regimen narrowed to CZA. On day 9, gram-positive cocci in chains in BC grew and VAN was added. BC finalized to VRE faecium and regimen was modified to ERV on day 12. Repeat BC on day 15 finalized to no growth with no recurrence of bacteremia until discharged (day 78). Patient 2 treated for MSSA bacteremia with cefazolin and subsequent K. pneumoniae VAP treated with ceftriaxone (CRO) (day 18-26). On day 27, meropenem (MEM) was initiated for gram-negative bacteremia and started on IV trimethoprim/sulfamethoxazole (TMP/SMX) the following day for pneumonia caused by TMP/SMX-susceptible S. maltophila. BC finalized on day 29 to S. maltophila resistant to TMP/SMX, regimen modified to ERV. Repeat BC on day 30 finalized to no growth and ERV was continued until day 42 with no recurrence of bacteremia; however, patient died on day 45. Patient 3 with renal failure and on day 11, CRO started for SBP prophylaxis. On day 13, switched to daptomycin and cefepime (FEP) as patient was febrile and BC repeated. BC finalized to VRE faecium and was started on ERV on day 17 and completed a 7-day course with no recurrence of bacteremia; however, patient died on day 34. Patient 4 initially treated for bacterial superinfection with CRO and azithromycin, and subsequent worsening pneumonia treated with VAN and MEM (day 10-17). On day 19, patient was febrile and treated with VAN and FEP until day 27. Repeat BC on day 29 finalized to VRE species and modified to ERV on day 32. ERV continued for a 7-day course and was discharged with no repeat BC obtained to confirm clearance. Patient 5 in SS started on VAN and MEM. On day 3, BC on admission finalized to VRE faecium and therapy switched to ERV. Repeat BC taken on day 3 after ERV initiation were negative. Discharged to complete two-week course of ERV.ConclusionERV may be an option for bacteremia as demonstrated by clearance in four of five cases. More studies must be conducted as these reports show variable clinical outcomes.Disclosures Joshua R. Rosenberg, MD, Allergan/Abbvie (Consultant)La Jolla/Tetraphase (Consultant)Melinta (Consultant)Merck (Consultant)Paratek (Consultant)Sanofi (Consultant)Shionogi (Consultant)

1288. Evaluation of Predictors for Clinical Success in Patients Treated with Eravacycline for Various Infections

Abstract Background Eravacycline (ERV) is approved in the United States (US) for the treatment of complicated intra-abdominal infections in adults. We aimed to evaluate the independent predictors of clinical success in patients treated with ERV for various infections. Methods Multicenter, retrospective, observational study conducted from September, 2018 to April, 2021. We included adults treated with ERV for ≥ 72hours. Clinical success was defined as 30-day survival, lack of 30-day infection-recurrence, and resolution of infection signs/symptoms. All outcomes were measured from ERV initiation. Multivariable logistic regression (MLR) was performed to identify independent predictors of clinical success. Clinically relevant variables were selected for model entry based on bivariate comparisons (P&amp;lt; 0.2) in a backward fashion. Results We included 223 patients from 16 medical centers in 13 geographically unique states. The median (IQR) age was 61 (50-69) years, 57% were male and 62% were Caucasian. Median (IQR) APACHE II, and Charlson Comorbidity scores were 15 (10-21), and 3 (1-5), respectively. Sources of infection were primarily intra-abdominal (27%) and respiratory (27%). Common pathogens included Acinetobacter baumannii (21%) and those of the Enterobacterales order (36%). Infectious diseases consultation and surgical interventions were obtained in 93.7% and 52% respectively. Clinical success occurred in 64%, specifically 30-day survival in 78%, absence of 30-day infection-recurrence in 93%, and 74% experienced resolution of infection signs/symptoms. Since characteristics and outcomes were similar among various pathogens, MLR was conducted using the overall cohort. Skin as a source and combination therapy with ERV were independently associated with higher clinical success: odds ratio 3.3 [CI 1.1-10.2] and 2.9 [1.4-5.9], respectively. Whereas, ICU admission at culture time and undergoing surgery within 30 days of culture were independently associated with reduced odds of clinical success: 0.4 [0.17-0.80] and 0.3 [0.11-0.63] respectively. Conclusion Although most ERV treated patients experienced clinical success, factors independently associated with higher clinical success are crucial to consider for optimum antibiotic selection. Disclosures Kimberly C. Claeys, PharmD, GenMark (Speaker’s Bureau) Madeline King, PharmD, tetraphase (Speaker’s Bureau) Michael P. Veve, Pharm.D., Cumberland (Grant/Research Support)Paratek Pharmaceuticals (Research Grant or Support) Bruce M. Jones, PharmD, BCPS, Abbvie (Consultant, Advisor or Review Panel member, Speaker’s Bureau)La Jolla (Speaker’s Bureau)Melinta (Consultant)Merck (Consultant)Paratek (Consultant, Speaker’s Bureau) Susan L. Davis, PharmD, Nothing to disclose Michael J. Rybak, PharmD, MPH, PhD, Paratek Pharmaceuticals (Research Grant or Support)

The European Medicines Agency Approved the New Antibacterial Drugs – Response to the 2017 Who Report on the Global Problem of Multi-Drug Resistance

Abstract The growing problem of antimicrobial resistance has been classified by the World Health Organization (WHO) as one of the top ten threats to mankind. In a special report published in 2017, the WHO presented a list of microorganisms for which the search for new therapeutic options is a priority. The highest (critical) priority was given to the search for new antibiotics active against carbapenem-resistant strains of Acinetobacter baumannii and Pseudomonas aeruginosa as well as against carbapenem- and third-generation-cephalosporin-resistant Enterobacterales strains (so-called critical priority pathogens). Whereas the second (high) priority was given among others to the search for new antibiotics active against methicillin- and vancomycin-resistant strains of Staphylococcus aureus (MRSA and VRSA) and vancomycin-resistant strains of Enterococcus faecium (VRE). Since the publication of the WHO report the European Medicines Agency has approved 6 novel, broad-spectrum antibiotics, from 6 different groups, addressing the priority pathogens to a different extent. Two of them are new combinations of carbapenems with non-β-lactam inhibitors of β-lactamases (active also against carbapenemases), belonging to two novel groups of inhibitors: diazabicyclooctanes (relebactam, combined with imipenem) and boronates (vaborbactam, combined with meropenem). The third new drug is a siderophore cephalosporin (cefiderocol) with an innovative mechanism of penetration into the bacterial cell. The next two antibiotics are the new fluoroquinolone (delafloxacin) and the new tetracycline (eravacycline), designed and synthesized to be more active than older members of these groups. The last innovative antibiotic is lefamulin – the first pleuromutilin approved for systemic use in humans. New approvals have expanded the number of available therapeutic options in the treatment of complicated urinary tract infections (meropenem/vaborbactam, cefiderocol), complicated intra-abdominal infections (meropenem/vaborbactam, eravacycline), nosocomial pneumonia (meropenem/vaborbactam, imipenem/relebactam), acute bacterial skin and skin structure infections (delafloxacin) and community-acquired pneumonia (lefamulin).

Composite Inflammatory Indicators as Early Predictor of Intra-abdominal Infections after General Surgery.

ObjectiveTo identify rapid and accurate early diagnostic indicators for intra-abdominal infection (IAI) after general surgery.MethodsWe conducted a retrospective analysis of 3,810 general surgical patients in our hospital from August 2017 to July 2018. The predictive value of PCT, CRP, TNFα, and IL6 on postoperative days (PODs) 1 and 3 and composite indicators for complicated IAIs among surgical patients was clarified.ResultsThere were 271 patients in the infected group and 614 patients in the uninfected group using IAI diagnostic criteria in this study. CRP, PCT, TNFα, and IL6 in the infected group were significantly higher than the uninfected group on POD1 and POD3. In the infected group, the composition of the four indicators on POD1 (AUC 0.819) and POD3 (AUC 0.848) showed higher predictive efficiency than the individual indicators (AUC 0.670–0.805).ConclusionThe composite of CRP, PCT, TNFα, and IL6 can be used as a predictor of postoperative abdominal infectious complications with high sensitivity and specificity on POD1 and POD3, which can provide a basis for early diagnosis of postoperative abdominal infectious complications.

Clinical management of cUTI, cIAI, and HABP/VABP attributable to carbapenem-resistant Gram-negative infections in Spain.

IntroductionCarbapenem-resistant Gram-negative (CRGN) infections are a major public health problem in Spain, often implicated in complicated, healthcare-associated infections that require the use of potentially toxic antibacterial agents of last resort. The objective of this study was to assess the clinical management of complicated infections caused by CRGN bacteria in Spanish hospitals.MethodsThe study included: 1) a survey assessing the GN infection and antibacterial susceptibility profile in five participating Spanish hospitals and 2) a non-interventional, retrospective single cohort chart review of 100 patients with complicated urinary tract infection (cUTI), complicated intra-abdominal infection (cIAI), or hospital-acquired bacterial pneumonia/ventilator-associated bacterial pneumonia (HABP/ VABP) attributable to CRGN pathogens.ResultsIn the participating hospitals CRGN prevalence was 9.3% amongst complicated infections. In the retrospective cohort, 92% of infections were healthcare-associated, and Klebsiella pneumoniae and Pseudomonas aeruginosa were the most common pathogens. OXA was the most frequently detected carbapenemase type (71.4%). We found that carbapenems were frequently used to treat cUTI, cIAI, HABP/VABP caused by CRGN pathogens. Carbapenem use, particularly in combination with other agents, persisted after confirmation of carbapenem resistance. Clinical cure was 66.0%, mortality during hospitalization 35.0%, mortality at the time of chart review 62.0%, and 6-months-post-discharge readmission 47.7%.ConclusionOur results reflect the high burden and unmet needs associated with the management of complicated infections attributable to CRGN pathogens in Spain and highlight the urgent need for enhanced clinical management of these difficult-to-treat infections.

A retrospective, multicentre evaluation of eravacycline utilisation in community and academic hospitals

Eravacycline is a novel, fully-synthetic tetracycline approved by the FDA for treatment of complicated intra-abdominal infections in August 2018. This study sought to characterise early clinical experience with this novel antibiotic. Eravacycline utilisation for 66 patients was retrospectively evaluated. Eravacycline was used as monotherapy in 62.1% of cases. Mean duration of therapy was 13.1 ± 9.9 days. The majority (68.2%) of treatment was for off-label indications, including 34.8% for pulmonary and 28.8% for skin/soft tissue infections. A number of difficult-to-treat organisms were encountered: 50% of identified Gram-negative pathogens were resistant to carbapenems in vitro; and 48% of identified Gram-positive pathogens were resistant to vancomycin in vitro. The patient population had a high illness acuity, with 42.4% requiring ICU admission, 59.1% having ≥2 co-morbidities and 33.3% having ≥3 co-morbidities. Nevertheless, 95.5% experienced clinical improvement, with 86.4% achieving full infection resolution following eravacycline. Three patients who did not experience clinical improvement had an intra-abdominal source of infection without adequate source control. The remaining six who did not experience full infection resolution died from unrelated non-infectious causes during hospital admission. Adverse events were uncommon (4.5%), limited to nausea/vomiting, and not leading to eravacycline discontinuation. Although two patients had a history of Clostridioides difficile infection (CDI), no patients developed CDI while receiving eravacycline. These results illustrate the potential versatility of eravacycline with a broad activity spectrum, good safety and tolerability profile, flexibility for use in patients with renal injury or antibiotic allergies, and positive clinical outcomes in this real-world cohort.