Date of Presentation
5-4-2023 12:00 AM
College
School of Osteopathic Medicine
Poster Abstract
Acinetobacter baumannii is an opportunistic pathogen common in intensive care units (ICUs), particularly among immunocompromised individuals. Nosocomial A. baumannii infections have become increasingly problematic in recent years, as these bacteria rapidly acquire antibiotic resistance, leading to the emergence of multidrug, extensively drug and pan drug-resistant (MDR, XDR, and PDR, respectively) isolates. Recently, Cooper University Hospital (CUH) experienced a large increase in highly drug-resistant A. baumannii infections, which had a mortality rate of 60%. Oftentimes, physicians had to turn to combinations of drugs with no experimental verification or historically shelved antibiotics, such as the polymyxins, in a desperate attempt to save lives. This highlights the critical need for more research to identify new, effective treatment options for these difficult-to-treat infections. Here, we determined the susceptibility of 22 patient isolates from CUH against 22 standard-of-care drugs and three newly released antibiotics (eravacycline, omadacycline and plazomicin) by the standard broth microdilution technique. We found that the isolates in this collection were 70% XDR and 30% PDR, meaning there were few to no treatment options available. Overall, the collection was most susceptible to minocycline (77.3%), followed by rifampin (55%) and amikacin (40.9%). While official breakpoint data is not available from the Clinical Laboratory Standards Institute for the new tetracycline-class drugs, a number of strains had low minimum inhibitory concentrations (MICs) to eravacycline and omadacycline, suggesting that these new drugs may be effective in treatment of highly drug-resistant strains. The drug plazomicin was largely ineffective against these strains, with high MICs. We plan to explore novel combinations of eravacycline and omadacycline with the standard-of-care drugs and to search for synergistic combinatorial effects using checkerboard assays. This information can ultimately be used to design new Therapeutics against drug-resistant A. baumannii infections.
Keywords
Acinetobacter baumannii, Acinetobacter Infections, Antibiotic Resistance, Antimicrobial Drug Resistance, Therapeutics, Treatment Outcome
Disciplines
Bacterial Infections and Mycoses | Critical Care | Health and Medical Administration | Internal Medicine | Medicine and Health Sciences | Pathological Conditions, Signs and Symptoms | Pharmaceutical Preparations | Therapeutics
Document Type
Poster
Included in
Bacterial Infections and Mycoses Commons, Critical Care Commons, Health and Medical Administration Commons, Internal Medicine Commons, Pathological Conditions, Signs and Symptoms Commons, Pharmaceutical Preparations Commons, Therapeutics Commons
Characterization of Antibiotic Susceptibility Profiles of Extensively- and Pan-Drug Resistant Acinetobacter Baumannii Clinical Isolates
Acinetobacter baumannii is an opportunistic pathogen common in intensive care units (ICUs), particularly among immunocompromised individuals. Nosocomial A. baumannii infections have become increasingly problematic in recent years, as these bacteria rapidly acquire antibiotic resistance, leading to the emergence of multidrug, extensively drug and pan drug-resistant (MDR, XDR, and PDR, respectively) isolates. Recently, Cooper University Hospital (CUH) experienced a large increase in highly drug-resistant A. baumannii infections, which had a mortality rate of 60%. Oftentimes, physicians had to turn to combinations of drugs with no experimental verification or historically shelved antibiotics, such as the polymyxins, in a desperate attempt to save lives. This highlights the critical need for more research to identify new, effective treatment options for these difficult-to-treat infections. Here, we determined the susceptibility of 22 patient isolates from CUH against 22 standard-of-care drugs and three newly released antibiotics (eravacycline, omadacycline and plazomicin) by the standard broth microdilution technique. We found that the isolates in this collection were 70% XDR and 30% PDR, meaning there were few to no treatment options available. Overall, the collection was most susceptible to minocycline (77.3%), followed by rifampin (55%) and amikacin (40.9%). While official breakpoint data is not available from the Clinical Laboratory Standards Institute for the new tetracycline-class drugs, a number of strains had low minimum inhibitory concentrations (MICs) to eravacycline and omadacycline, suggesting that these new drugs may be effective in treatment of highly drug-resistant strains. The drug plazomicin was largely ineffective against these strains, with high MICs. We plan to explore novel combinations of eravacycline and omadacycline with the standard-of-care drugs and to search for synergistic combinatorial effects using checkerboard assays. This information can ultimately be used to design new Therapeutics against drug-resistant A. baumannii infections.