Growth of Bordetella species in tracheobronchial washings and in other low-nutrient fluids

Porter, John Francis (1991) Growth of Bordetella species in tracheobronchial washings and in other low-nutrient fluids. PhD thesis, University of Glasgow.

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Abstract

This study has shown that three species of Bordetella, B. bronchiseptica, B. avium and B. parapertussis, are capable of growth in vertebrate tracheobronchial washings (TBW), while B. pertussis is not. A total of nine samples of TBW from man, horse, mouse, rabbit, sheep, dog and chicken exhibited differences in growth-sup porting abilities as judged from colony counts on Bordet-Gengou (BG) agar plates (from inocula of about 2000 CFU/ml). Single samples of TBW from horse and mouse gave higher stationary-phase counts of B. bronchiseptica and B. avium, than any of the other TBW. However additional samples would have to be tested to determine whether this is a consistent species effect or is due to between-sample variation. With human TBW, where three samples were tested, there was considerable between-sample variation. As regards the differences between the bordetellae, B. bronchiseptia. strain 5376 (Eldering strain) grew in all species of TBW, except that one out of three human specimens appeared to be bactericidal. The stationary-phase viable counts (colony forming units; CFU) with the other samples were all in the 12-fold range 7.9 to 9.1 (Log10 CFU/ml). B. avium strain P4091 behaved, in general, very similarly to B. bronchiseptica except that the average final viable counts were slightly lower. Thus although B. avium is exclusively an avian parasite, its growth in chicken TBW was not greater than in mammalian TBW; in fact, it grew least well in the avian fluid. With the two human bordetellae, B. pertussis strain 18334J showed no evidence of growth in any of the TBW, although there was consistent and extensive growth in the control fluid, CL medium, where counts of 10.0 log10 CFU/ml were reached from inocula of around 3.3 log10 CFU/ml. B. parapertussis (strain 10520) was the organism that exhibited the greatest variation of growth in the different TBW. Thus, it grew to levels of 5.5-67 log10 CFU/mi in TBW from chicken, sheep, rabbit, mouse and two human samples, while it failed to grow in the horse and dog TBW which had supported extensive growth of B. broncchiseptica and B. avium. In Cl medium, B. parapertussis reached counts of 9.5 log10 CFU/ml i.e. slightly lower than B. pertussis With B. pertussis, an attempt was made to determine whether the failure to grow in TBW (rabbit was chosen) was due to lack of nutrients or to the presence of inhibitors. This was explored by comparing growth in a) TBW, b) CL medium, c) a 1:1 mixture of TBW and CL medium and d) TBW and MeBCD (methylated cyclodextrin). The observed growth in (b) and (c) but not in (a) or (d) suggested that lack of nutrients, rather than the presence of inhibitors was the likely explanation. Since amino acids are primary nutrients of bordetellae in laboratory culture media, it was necessary to analyse TBW for their amino acid content. This was done by the ninhydrin method. All samples of TBW had readily detectable amounts of amino acids, the concentrations ranging from 0.1 to 0.81 mM, expressed as leucine equivalents. The 0.81 mM is approximately 1/200 the level of amino acids in CL medium, yet it supported growth of B. bronchiseptica to a level only 2-fold lower than CL medium. There was a statistically significant correlation between the amount of growth and the amino acid concentration with B. bronchiseptica and B. avium in TBW; but this was not so with B. parapertussis Nicotinic acid was likewise readily detected in TBW by microbiological assay with Lactobacilluspiantarum. Values ranged from 0.2 to 1.06 ug/oiL which was about 20-fold less than in conventional Bordetella media. As with the amino acid values, there was some correlation between the nicotinic acid content of TBW and the level of stationary-phase CFU/ml of B. bronchiseptica and B. avium, but not of B. parapertussis. (Abstract shortened by ProQuest.).

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: Alastair C Wardlaw
Keywords: Microbiology
Date of Award: 1991
Depositing User: Enlighten Team
Unique ID: glathesis:1991-72800
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 11 Jun 2019 11:06
Last Modified: 11 Jun 2019 11:06
URI: http://theses.gla.ac.uk/id/eprint/72800

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