title: Intrinsic Resistance of Burkholderia cepacia Complex to Benzalkonium Chloride.
abstract: Pharmaceutical products that are contaminated with Burkholderia cepacia complex (BCC) bacteria may pose serious consequences to vulnerable patients. Benzyldimethylalkylammonium chloride (BZK) cationic surfactants are extensively used in medical applications and have been implicated in the coselection of antimicrobial resistance. The ability of BCC to degrade BZK, tetradecyldimethylbenzylammonium chloride (C14BDMA-Cl), dodecyldimethylbenzylammonium chloride (C12BDMA-Cl), decyldimethylbenzylammonium chloride (C10BDMA-Cl), hexyldimethylbenzylammonium chloride, and benzyltrimethylammonium chloride was determined by incubation in 1/10-diluted tryptic soy broth (TSB) to determine if BCC bacteria have the ability to survive and inactivate these disinfectants. With BZK, C14BDMA-Cl, and C12BDMA-Cl, inhibition of the growth of 20 BCC strains was observed in disinfectant solutions that ranged from 64 to 256 µg/ml. The efflux pump inhibitor carbonyl cyanide m-chlorophenylhydrazone increased the sensitivity of bacteria to 64 µg/ml BZK. The 20 BCC strains grew well in 1/10-diluted TSB medium with BZK, C12BDMA-Cl, and C10BDMA-Cl; they absorbed and degraded the compounds in 7 days. Formation of benzyldimethylamine and benzylmethylamine as the initial metabolites suggested that the cleavage of the C alkyl-N bond occurred as the first step of BZK degradation by BCC bacteria. Proteomic data confirmed the observed efflux activity and metabolic inactivation via biodegradation in terms of BZK resistance of BCC bacteria, which suggests that the two main resistance mechanisms are intrinsic and widespread.
  
  
  
  Benzyldimethylalkylammonium chloride is commonly used as an antiseptic in the United States. Several recent microbial outbreaks were linked to antiseptics that were found to contain strains of the Burkholderia cepacia complex. Burkholderia species survived in antiseptics, possibly because of the degradation of antiseptic molecules or regulation of relevant gene expression. In this study, we assessed the efflux pump and the potential of B. cepacia complex bacteria to degrade benzyldimethylalkylammonium chloride and improved our understanding of the resistance mechanisms, by using proteomic and metabolic information. To our knowledge, this is the first systematic report of the intrinsic mechanisms of B. cepacia complex strain resistance to benzyldimethylalkylammonium chloride, based on the metabolic and proteomic evidence for efflux pumps and the complete biodegradation of benzyldimethylalkylammonium chloride.
authors.affiliation: Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA.
authors.forename: Youngbeom
authors.initials: Y
authors.lastname: Ahn
authors.affiliation: Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA.
authors.forename: Jeong Myeong
authors.initials: JM
authors.lastname: Kim
authors.affiliation: Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA.
authors.forename: Ohgew
authors.initials: O
authors.lastname: Kweon
authors.affiliation: Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA.
authors.forename: Seong-Jae
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: MS, Bioworks LLC, Ann Arbor, Michigan, USA.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Jones
authors.affiliation: Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA.
authors.forename: Kellie
authors.initials: K
authors.lastname: Woodling
authors.affiliation: Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA.
authors.forename: Gonçalo
authors.initials: G
authors.lastname: Gamboa da Costa
authors.affiliation: Department of Pediatrics & Communicable Diseases, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: LiPuma
authors.affiliation: Office of Pharmaceutical Science, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA.
authors.forename: David
authors.initials: D
authors.lastname: Hussong
authors.affiliation: Division of Microbiology Assessment, Office of Pharmaceutical Quality, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA.
authors.forename: Bernard S
authors.initials: BS
authors.lastname: Marasa
authors.affiliation: Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA Carl.Cerniglia@fda.hhs.gov.
authors.forename: Carl E
authors.initials: CE
authors.lastname: Cerniglia
mesh_terms: D000891:Anti-Infective Agents, Local / Q000378:metabolism / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000032:analysis; D001548:Benzalkonium Compounds / Q000378:metabolism / Q000494:pharmacology*; D001711:Biotransformation; D042602:Burkholderia cepacia complex / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D024881:Drug Resistance, Bacterial; D020869:Gene Expression Profiling; D050296:Microbial Viability / Q000187:drug effects; D020543:Proteome / Q000032:analysis
chemical_list: D000891:Anti-Infective Agents, Local; D001426:Bacterial Proteins; D001548:Benzalkonium Compounds; D020543:Proteome