Christine Greene1, Gayathri Vadlamudi1, Duane Newton2, Betsy Foxman3, Chuanwu Xi4. 1. Department of Environmental Health and Science, University of Michigan, Ann Arbor, MI. 2. Department of Epidemiology, University of Michigan, Ann Arbor, MI; Department of Pathology, University of Michigan, Ann Arbor, MI. 3. Department of Epidemiology, University of Michigan, Ann Arbor, MI. 4. Department of Environmental Health and Science, University of Michigan, Ann Arbor, MI. Electronic address: cxi@umich.edu.
Abstract
BACKGROUND: Acinetobacter baumannii is a gram-negative, opportunistic pathogen. Its ability to form biofilm and increasing resistance to antibiotic agents present challenges for infection control. A better understanding of the influence of biofilm formation and antibiotic resistance on environmental persistence of A baumannii in hospital settings is needed for more effective infection control. METHODS: A baumannii strains isolated from patients and the hospital environment were identified via Matrix Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF) mass spectrometry (Bruker Daltonics, Bellerica, MA), repetitive extragenic palindromic polymerase chain reaction genotyped, and antibiotic resistance was determined using Vitek 2 (bioMérieux, Inc, Durham NC). Biofilm mass was quantified via microtiter plate method and desiccation tolerance determined up to 56 days. RESULTS: High biofilm forming, clinical, multidrug-resistant- (MDR) positive strains were 50% less likely to die of desiccation than low biofilm, non-MDR strains. In contrast, environmental, MDR-positive, low biofilm forming strains had a 2.7 times increase in risk of cell death due to desiccation compared with their MDR-negative counterparts. MDR-negative, high biofilm forming environmental strains had a 60% decrease in risk compared with their low biofilm forming counterparts. CONCLUSION: The MDR-positive phenotype was deleterious for environmental strains and the high biofilm phenotype was critical for survival. This study provides evidence of the trade-off between antibiotic resistance and desiccation tolerance, driven by condition-dependent adaptation, and establishes rationale for research into the genetic basis of the variation in fitness cost between clinical and environmental isolates.
BACKGROUND:Acinetobacter baumannii is a gram-negative, opportunistic pathogen. Its ability to form biofilm and increasing resistance to antibiotic agents present challenges for infection control. A better understanding of the influence of biofilm formation and antibiotic resistance on environmental persistence of A baumannii in hospital settings is needed for more effective infection control. METHODS: A baumannii strains isolated from patients and the hospital environment were identified via Matrix Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF) mass spectrometry (Bruker Daltonics, Bellerica, MA), repetitive extragenic palindromic polymerase chain reaction genotyped, and antibiotic resistance was determined using Vitek 2 (bioMérieux, Inc, Durham NC). Biofilm mass was quantified via microtiter plate method and desiccation tolerance determined up to 56 days. RESULTS: High biofilm forming, clinical, multidrug-resistant- (MDR) positive strains were 50% less likely to die of desiccation than low biofilm, non-MDR strains. In contrast, environmental, MDR-positive, low biofilm forming strains had a 2.7 times increase in risk of cell death due to desiccation compared with their MDR-negative counterparts. MDR-negative, high biofilm forming environmental strains had a 60% decrease in risk compared with their low biofilm forming counterparts. CONCLUSION: The MDR-positive phenotype was deleterious for environmental strains and the high biofilm phenotype was critical for survival. This study provides evidence of the trade-off between antibiotic resistance and desiccation tolerance, driven by condition-dependent adaptation, and establishes rationale for research into the genetic basis of the variation in fitness cost between clinical and environmental isolates.
Authors: Ursula Waack; Tanya L Johnson; Khalil Chedid; Chuanwu Xi; Lyle A Simmons; Harry L T Mobley; Maria Sandkvist Journal: Front Cell Infect Microbiol Date: 2017-08-28 Impact factor: 5.293
Authors: María Lázaro-Díez; Itziar Chapartegui-González; Santiago Redondo-Salvo; Chike Leigh; David Merino; David San Segundo; Adrián Fernández; Jesús Navas; José Manuel Icardo; Félix Acosta; Alain Ocampo-Sosa; Luis Martínez-Martínez; José Ramos-Vivas Journal: Sci Rep Date: 2017-07-04 Impact factor: 4.379