Haematological Evaluation of Sprague-Dawley Rats Infected With Pasteurella Multocida and Administered Bdellovibrio Bacteriovorus (Atcc™ 1534) as Therapy

Abstract

The effects on haematological parameters of Sprague-Dawley rats infected (challenged) by the injection of pathogenic Pasteurella multocida and the administration of Bdellovibrio bacteriovorus (ATCC™ 1534) as therapy, occasioned by the consideration of its use as an alternative to antibiotics, due to the high rate of bacterial resistance to current clinically used antibiotics was investigated. A total of 60 rats, divided into 5 groups (4 experimental groups and 1 control group) of 12 rats each were used in this study. The first group of 12 rats were injected subcutaneously with one millilitre of 1 x 108/ml B. bacteriovorus (ATCC™ 1534). The second group of 12 rats were injected with one millilitre 108/ml of P. multocida in saline. One millilitre each of 108/ml of both P. multocida and B. bacteriovorus (ATCC™ 1534) were injected into another set of 12 rats in the third group. The third group of 12 rats were injected once intra-muscularly, in the hind flank muscle, with 2 mg/kg of Ketamine Hydrochloride. And lastly, one set of 12 rats were not injected with any bacteria served as control. In all cases, observed haematological data were analysed from the experimental rats after 168 hours (except rats which were injected with 2mg/kg ketamine hydrochloride, used as anaesthetic, (at sacrifice), and compared with the haematological profiles of the 12 control rats. Results shows a reduction of mortality from 9 to 1 (88.8%) of rats challenged with P. multocida over those inoculated with B. bacteriovorus and P. multocida was observed. WBC counts were higher (4.12 x 103/µL) in B. bacteriovorus and P. multocida over WBC counts in control rats which served as WBC reference values. Though, not statistically significant (ANOVA = p >0.05). In a similar comparison, RBC counts (6.5 x 103/µL) were lower than observed in control rats, while platelet counts (1138 x 103/µL) were higher than values in controls, however, this was statistically significant. Moreover, haemoglobin concentrations were lower (11.7 g/dL) than in control rats. Though there were slight variations in haematological profiles from reference values, it was concluded that B. bacteriovorus seems to have no life-threatening effect on haematology of rats. However, evaluations such as observed platelet increases on inoculations of B. bacteriovorus, need to be addressed before the promise of its in vivo use in controlling Gram-negative infection in animals and humans can be tapped.
 Sar, T. T. | Department of Biological Sciences, University of Agriculture, Makurdi, Benue State, Nigeria

Bdellovibrio bacteriovorus: A Boost for Hematological and Gut Health in Salmonella enteritidis-Infected Mice

“…Previously studies showed that administration of Bdellovibrio bacteriovorus increased the number of leukocytes and decreased the number of RBC and platelets in mice inoculated with Pasteurella multocida and had no effect on rat hematology (Pan et al 2011;Sar et al 2020). Furthermore, B bacteriovorus (Bb) as an intracellular bacterium, produces hydrolase enzymes, which digest host cell contents to provide nutrients for growth and nuclease enzymes, thus degrading the target bacterial DNA.…”

The role of mathematical modelling in understanding prokaryotic predation

“…Several studies have addressed the issue of safety of Bdellovibrio and like organisms (BALOs; Lenz and Hespell, 1978 ; Shatzkes et al, 2015 ; Gupta et al, 2016 ; Monnappa et al, 2016 ) and found BALOs to be non-toxic to eukaryotic cells and only mildly immunogenic ( Gupta et al, 2016 ; Shatzkes et al, 2016 , 2017 ), probably due to their unusual lipid A ( Schwudke et al, 2003 ). The effectiveness of BALOs in treating various bacterial infections has been investigated in plants ( Scherff, 1973 ; Uematsu, 1980 ; Paulis, 2017 ; Youdkes et al, 2020 ), corals ( Welsh et al, 2017 ), fungi ( Saxon et al, 2014 ), nematodes ( Emmert et al, 2014 ), fruit flies ( Sivakala et al, 2021 ), mice, rats and rabbits ( Shatzkes et al, 2016 , 2017 ; Russo et al, 2018 ; Findlay et al, 2019 ; Sar et al, 2020 ; Romanowski et al, 2021 ), farm animals ( Atterbury et al, 2011 ; Boileau et al, 2011 , 2016 ) and aquaculture ( Chu and Zhu, 2009 ; Richards et al, 2012 ; Li et al, 2014 ; Cao et al, 2015 , 2020 ; Guo et al, 2017 ; Ottaviani et al, 2020 ; Ooi et al, 2021 ), as well as in combination with the immune system ( Willis et al, 2016 ) or antibiotics ( Im et al, 2017a ). Meanwhile, a great many studies have explored the possibilities of treating infections with bacteriophages over the last 100 years ( Gordillo Altamirano and Barr, 2019 ; Hatfull et al, 2022 ).…”