Disparate properties of Burkholderia multivorans and Pseudomonas aeruginosa regarding outer membrane chemical permeabilization to the hydrophobic substances novobiocin and triclosan.

Burkholderia multivorans causes opportunistic pulmonary infections and is intrinsically resistant to many antibacterial compounds including the hydrophobic biocide triclosan. Chemical permeabilization of the Pseudomonas aeruginosa outer membrane affects sensitization to hydrophobic substances. The purpose of the present study was to determine if B. multivorans is similarly susceptive suggesting that outer membrane impermeability properties underlie triclosan resistance. Antibiograms and conventional macrobroth dilution bioassays were employed to establish baseline susceptibility levels to hydrophobic antibacterial compounds. Outer membrane permeabilizers compound 48/80, polymyxin B, polymyxin B-nonapeptide, and ethylenediaminetetraacetic acid were used in attempts to sensitize disparate B. multivorans isolates to the hydrophobic agents novobiocin and triclosan, and to potentiate partitioning of the hydrophobic fluorescent probe 1-N-phenylnapthylamine (NPN). The lipophilic agent resistance profiles for all B. multivorans strains were essentially the same as that of P. aeruginosa except that they were resistant to polymyxin B. Moreover, they resisted sensitization to hydrophobic compounds and remained inaccessible to NPN when treated with outer membrane permeabilizers. These data support the notion that while both phylogenetically-related organisms exhibit general intrinsic resistance properties to hydrophobic substances, the outer membrane of B. multivorans either resists permeabilization by chemical modification or sensitization is mitigated by a supplemental mechanism not present in P. aeruginosa.

Characterization of persons with reported SARS-CoV-2 infection in the Oklahoma City tri-county area: Evidence from the first 12 months of transmission.

BACKGROUND: To describe characteristics, hospitalization, and death for reported cases of SARS-CoV-2 infection in the Oklahoma City tri-county area. METHODS: We extracted notified cases of SARS-CoV-2 infection for our study area and used descriptive statistics and modeling to examine case characteristics and calculate the odds of hospitalization and death in relation to a range of explanatory variables. RESULTS: Between March 12th, 2020 and February 28th, 2021, 124,925 cases of SARS-CoV-2 infection were reported from the study region. Being male, White or Black/African American, aged 50 years or older, presenting with apnea, cough, and shortness of breath, and having diabetes was associated with increased odds of hospitalization. The odds of dying were significantly associated with being Black/African American, presenting with cough and fever, having kidney disease and diabetes and being aged 70 years or older. CONCLUSIONS: The first cohort analysis of SARS-CoV-2 positive individuals in the Oklahoma City tri-county area confirms comorbidities and age as important predictors of COVID-19 hospitalization or death. As a novel aspect, we show that early symptoms of breathing difficulties in particular are associated with hospitalization and death. Initial case assessment and SARS-CoV-2 guidelines should continue to focus on age, comorbidities, and early symptoms.

Disparate outer membrane exclusionary properties underlie intrinsic resistance to hydrophobic substances in Pseudomonas spp. isolated from surface waters under triclosan selection.

Representative members of surface water microbiota were obtained from three unrelated municipal sites in Oklahoma by direct plating under selection by the hydrophobic biocide triclosan. Multiple methods were employed to determine if intrinsic triclosan resistance reflected resistance to hydrophobic molecules by virtue of outer membrane impermeability. While all but one organism isolated in the absence of triclosan were able to initiate growth on MacConkey agar, only one was able to initiate significant growth with triclosan present. In contrast, all bacteria selected with triclosan were identified as Pseudomonas spp. using 16S RNA gene sequencing and exhibited growth comparable to Pseudomonas aeruginosa controls in the presence of hydrophobic antibacterial agents to include triclosan. Two representative bacteria isolated in the absence of triclosan allowed for greater outer membrane association with the fluorescent hydrophobic probe 1-N-phenylnapthylamine than did two triclosan-resistant isolates. Compound 48/80 disruption of outer membrane impermeability properties for hydrophobic substances either partially or fully sensitized nine of twelve intrinsically resistant isolates to triclosan. These data suggest that outer membrane exclusion underlies intrinsic resistance to triclosan in some, but not all Pseudomonas spp. isolated by selection from municipal surface waters and implicates the involvement of concomitant triclosan resistance mechanisms.