title: Boronic acid disk diffusion for the phenotypic detection of polymerase chain reaction-confirmed, carbapenem-resistant, gram-negative bacilli isolates.
abstract: The Middle East is regarded as a secondary reservoir for OXA-48 and New Delhi metallo-β-lactamase (NDM) carbapenemases. One of the main challenges in clinical microbiology diagnostics is the detection of carbapenemases. For this reason simple screening methods have been sought to detect carbapenemase producers to determine appropriate therapeutic measures and implement infection control interventions. The present study aimed to evaluate the efficacy of the modified Hodge test (MHT) and a boronic acid-based combined disk test using carbapenems as substrates for the phenotypic determination of OXA-48 and NDM type carbapenemases in 45 epidemiologically unrelated carbapenem-resistant clinical isolates of Klebsiella pneumoniae (13 isolates), Acinetobacter baumanii (20 isolates), and Pseudomonas aeruginosa (12 isolates).
  
  
  
  Boronic acid disk test using meropenem as substrate and 600 µg of 3- aminophenylboronic acid (APB) was the most sensitive method (83.33 %) for detection of OXA-48, while the most specific method was MHT (100 %). As regards NDM carbapenemase, boronic acid disk tests using imipenem and 600 µg of APB per disk, and meropenem with 300 or 600 µg of APB were the most  sensitive methods (87.50 %), while the most specific method was the MHT (100 %).
  
  
  
  The results of the present study indicate that phenotypic screening with the MHT and the boronic acid disk test may be used to detect OXA-48 and NDM carbapenemases in Gram-negative bacilli clinical isolates, and that these tests can be easily applied in tertiary care settings with minimal infrastructure.
authors.affiliation: Clinical and Chemical Pathology Department, Faculty of Medicine, Cairo University, Giza, Egypt.
authors.forename: Rasha
authors.initials: R
authors.lastname: Elsherif
authors.affiliation: Clinical and Chemical Pathology Department, Faculty of Medicine, Cairo University, Giza, Egypt.
authors.forename: Dalia
authors.initials: D
authors.lastname: Ismail
authors.affiliation: Clinical and Chemical Pathology Department, Faculty of Medicine, Cairo University, Giza, Egypt.
authors.forename: Sanaa
authors.initials: S
authors.lastname: Elawady
authors.affiliation: Biology Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Samyah
authors.initials: S
authors.lastname: Jastaniah
authors.affiliation: Biology Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Saad
authors.initials: S
authors.lastname: Al-Masaudi
authors.affiliation: Special Infectious Agents Unit-Biosafety Level 3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, 21589, Saudi Arabia. sharakeh@gmail.com.
authors.forename: Steve
authors.initials: S
authors.lastname: Harakeh
authors.affiliation: Medical Physics Department, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia. drgamalkarrouf@yahoo.com.|Surgery, Anesthesiology and Radiology Department, Faculty of Veterinary Medicine, Mansoura University, Mansoura, 35516, Dakahlia, Egypt. drgamalkarrouf@yahoo.com.
authors.forename: Gamal
authors.identifier: 0000-0002-2260-5620
authors.initials: G
authors.lastname: Karrouf
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism; D001897:Boronic Acids / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D015780:Carbapenems / Q000494:pharmacology*; D052978:Disk Diffusion Antimicrobial Tests / Q000379:methods*; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology; D006801:Humans; D015378:Imipenem / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D000077731:Meropenem; D010641:Phenotype; D016133:Polymerase Chain Reaction / Q000379:methods; D013845:Thienamycins / Q000494:pharmacology; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001897:Boronic Acids; D015780:Carbapenems; D013845:Thienamycins; C028592:3-aminobenzeneboronic acid; D015378:Imipenem; D001618:beta-Lactamases; C063912:carbapenemase; D000077731:Meropenem
keywords: Boronic acid; Carbapenem; Disk diffusion Enterobacteriaceae; Phenotypic screening