The Sensitivity of Gram-negative Bacteria, Recovered from Aerosols, to Lysozyme and Other Hydrolytic Enzymes

Hambleton, Peter

doi:10.1099/00221287-61-2-197

Cited by 17 publications

(7 citation statements)

References 11 publications

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“…Lysozyme causes degradation of the mucopeptide layer, but in gram-negative bacteria this layer lies beneath the lipopolysaccharide (LPS) layer of the cell wall and usually remains inaccessible to lysozyme action (4,5). However, once this LPS layer is removed or undergoes some steric or chemical change, lysozyme is able to hydrolyze mucopeptide (6,7,10). The lysozyme susceptibility of the freeze-injured S. anatum cells may have been due to some alteration in the LPS layer.…”

Section: Resultsmentioning

confidence: 99%

Characterization of the Repair of Injury Induced by Freezing Salmonella anatum1

Ray

Janssen

Busta

1972

Applied Microbiology

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Fast freezing and slow thawing of Salmonella anatum cells suspended in water resulted in injury of more than 90% of the cells that survived the treatment. The injured cells failed to form colonies on the selective medium (xyloselysine-peptone-agar with 0.2% sodium deoxycholate) but did form colonies on a nonselective (xylose-lysine-peptone-agar) plating medium. In Tryptic soy plus 0.3% yeast extract broth or minimal broth, most of the injured cells repaired within 1 to 2 hr at 25 C. Tryptic soy plus yeast extract broth supported repair to a greater extent than minimal broth. Phosphate or citrate at concentrations found in minimal broth supported repair of some cells. MgSO4, when present with inorganic phosphate or citrate or both, increased the extent of repair. The repair process in the presence of phosphate was not prevented by actinomycin D, chloramphenicol, and D-cycloserine, but was prevented by cyanide and 2,4dinitrophenol (only at pH 6). This suggested that the repair process might involve energy metabolism in the form of adenosine triphosphate. The freeze-injured cells were highly sensitive to lysozyme, whereas unfrozen fresh cells were not. In the presence of phosphate or minimal broth this sensitivity was greatly reduced. This suggested that, at least in some of the cells, the injury involved the lipopolysaccharide of the cell wall and adenosine triphosphate synthesis-was required for repair.

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Section: Resultsmentioning

confidence: 99%

Characterization of the Repair of Injury Induced by Freezing Salmonella anatum1

Ray

Janssen

Busta

1972

Applied Microbiology

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“…Aerosol generation and sampling prior to microbiological analysis are conducted for a range of bioaerosol-related research activities (e.g., determination of aerosol decay rates and inhalational infectious dose, efficacy of decontamination strategies, and evaluation of bioaerosol sampling technologies). These dynamic processes can cause damage due to shear forces acting on the microbial cells ( 12 – 27 ). Table 1 outlines some major aerosol generators and samplers used in aerobiological studies and their operating mechanisms.…”

Section: Aerosol Generation Sampling and Postprocessing Consideratimentioning

confidence: 99%

Aerobiology: Experimental Considerations, Observations, and Future Tools

Haddrell

Thomas

2017

Appl Environ Microbiol

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Understanding airborne survival and decay of microorganisms is important for a range of public health and biodefense applications, including epidemiological and risk analysis modeling. Techniques for experimental aerosol generation, retention in the aerosol phase, and sampling require careful consideration and understanding so that they are representative of the conditions the bioaerosol would experience in the environment. This review explores the current understanding of atmospheric transport in relation to advances and limitations of aerosol generation, maintenance in the aerosol phase, and sampling techniques. Potential tools for the future are examined at the interface between atmospheric chemistry, aerosol physics, and molecular microbiology where the heterogeneity and variability of aerosols can be explored at the single-droplet and single-microorganism levels within a bioaerosol. The review highlights the importance of method comparison and validation in bioaerosol research and the benefits that the application of novel techniques could bring to increasing the understanding of aerobiological phenomena in diverse research fields, particularly during the progression of atmospheric transport, where complex interdependent physicochemical and biological processes occur within bioaerosol particles.

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“…The poor recovery of C. jejuni (significantly lower than 100%) is probably because the aerosolization was done in an isolator with an oxygen content similar to that of ambient air, where C. jejuni cannot survive well as it is a micro-aerophilic bacterial species (Goodhew et al 1988). Furthermore, the outer membranes of Gram-negative bacteria are more susceptible to rupture during aerosolization (Hambleton 1970). M. synoviae, the bacterial species without cell wall, was not affected by aerosolization stress.…”

Section: Effect Of Pre-sampling Process On Bacterialmentioning

confidence: 99%

Investigation of the Efficiencies of Bioaerosol Samplers for Collecting Aerosolized Bacteria Using a Fluorescent Tracer. I: Effects of Non-sampling Processes on Bacterial Culturability

Zhao

Aarnink

Doornenbal

et al. 2011

Aerosol Science and Technology

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By sampling aerosolized microorganisms, the efficiency of a bioaerosol sampler can be calculated depending on its ability both to collect microorganisms and to preserve their culturability during a sampling process. However, those culturability losses in the nonsampling processes should not be counted toward the sampling efficiency. Prior to the efficiency assessment, this study was designed to investigate the culturability losses in three non-sampling processes: (1) the tracer uranine induced loss; (2) the loss during aerosolization (pre-sampling process); and (3) the bacteria and uranine recovery in air sample handling procedures for the samples of the Andersen 6-stage impactor and the Airport MD8 (postsampling process).The results indicated that uranine had no significant effect on the culturability of Enterococcus faecalis, Escherichia coli, and Mycoplasma synoviae in suspensions (P > 0.05), but negatively affected the culturability of Campylobacter jejuni (P = 0.01). The culturability of E. faecalis, E. coli, and M. synoviae was not affected by stresses caused by aerosolization (P > 0.05). Only 29% of C. jejuni were still culturable during aerosolization (P = 0.02). In the air sample handling procedures, the four species of bacteria were recovered without significant losses from the samples of the Andersen impactor, but only 33-60% uranine was recovered. E. faecalis, E. coli, and M. synoviae were recovered without significant losses from the samples of the Airport MD8. More C. jejuni was recovered (172%), probably due to multiplication or counting variation.Received 9 August 2010; accepted 20 November 2010. We thank Ms. Thea von Bannisseht, Ms. Contance Reugebrink, Mr. Jean Slangen, and Mr. Frans Putirulan for analyzing the samples, Ms. Tao Nan, Mr. Machiel Esmann, Mr. Wilco Vije, and Mr. Huub van de Sande for helping in this experiment. We also express our appreciation to Mr. Eef Lovink for carefully checking and calibrating the equipment.Address correspondence to Andre J. A. Aarnink, Wageningen UR Livestock Research, P.O. Box 65, 8200 AB Lelystad, the Netherlands. E-mail: andre.aarnink@wur.nl It is suggested that tracer and bacteria should be aerosolized separately when the tracer negatively affects the bacterial culturability. In both pre-and post-sampling processes, losses of bacterial culturability (or multiplication) may occur, which should be taken into account when assessing the efficiencies of bioaerosol samplers.

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The Sensitivity of Gram-negative Bacteria, Recovered from Aerosols, to Lysozyme and Other Hydrolytic Enzymes

Cited by 17 publications

References 11 publications

Characterization of the Repair of Injury Induced by Freezing Salmonella anatum1

Characterization of the Repair of Injury Induced by Freezing Salmonella anatum1

Aerobiology: Experimental Considerations, Observations, and Future Tools

Investigation of the Efficiencies of Bioaerosol Samplers for Collecting Aerosolized Bacteria Using a Fluorescent Tracer. I: Effects of Non-sampling Processes on Bacterial Culturability

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