Dataset Information

Effect of aerosolized bacterial lysate on development of naturally occurring respiratory disease in beef calves.

ABSTRACT:

Background

Bovine respiratory disease (BRD) is a major problem affecting beef cattle after arrival to feedlots. Alternatives to antibiotics are needed for prevention.

Hypothesis

Stimulation of pulmonary innate immune responses at the time of arrival to a feedlot reduces the occurrence and severity of BRD.

Animals

Sixty beef steers at high risk of BRD.

Methods

Randomized, double-blinded, placebo-controlled study. Calves received saline or a lysate of Staphylococcus aureus and Escherichia coli by aerosol, at 16?hours after feedlot arrival. Calves were monitored for 28?days for disease outcomes and levels of Mycoplasma bovis and Mannheimia haemolytica in nasal swabs.

Results

Death from M?bovis pneumonia was significantly greater in lysate-treated animals (6/29, 24%) compared to controls (1/29, 3%; odds ratio = 10.2; 95% confidence interval [CI] = 1.1-96.0; P = .04). By 28?days after arrival, 29/29 lysate-treated calves had ultrasonographic pulmonary consolidation compared to 24/29 control calves (P = .05). Lysate-treated calves had lower weight gain compared to control calves (-8.8 kg, 95% CI = -17.1 to -0.5; P = .04), and higher body temperatures on days 4, 7, and 21 (0.19°C; 95% CI = 0.01-0.37; P = .04). Nasal M?bovis numbers increased over time and were higher in lysate-treated calves (0.76 log?CFU, 95% CI = 0.3-1.2; P = .001).

Conclusions and clinical importance

Aerosol administration of a bacterial lysate exacerbated BRD in healthy high-risk beef calves, suggesting that respiratory tract inflammation adversely affects how calves respond to subsequent natural infection with M?bovis and other respiratory pathogens.

SUBMITTER: Bassel LL

PROVIDER: S-EPMC7848379 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Publications

Effect of aerosolized bacterial lysate on development of naturally occurring respiratory disease in beef calves.

Bassel Laura L LL Kaufman Emily I EI Alsop Sarah-Nicole A SA Buchan Jordan J Hewson Joanne J McCandless Erin E EE Tiwari Raksha R Sharif Shayan S Vulikh Ksenia K Caswell Jeff L JL

Journal of veterinary internal medicine 20210113 1

<h4>Background</h4>Bovine respiratory disease (BRD) is a major problem affecting beef cattle after arrival to feedlots. Alternatives to antibiotics are needed for prevention.<h4>Hypothesis</h4>Stimulation of pulmonary innate immune responses at the time of arrival to a feedlot reduces the occurrence and severity of BRD.<h4>Animals</h4>Sixty beef steers at high risk of BRD.<h4>Methods</h4>Randomized, double-blinded, placebo-controlled study. Calves received saline or a lysate of Staphylococcus au ...[more]

PMID: 33442910

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Project description:BACKGROUND:Constitutive and inducible defenses protect the respiratory tract from bacterial infection. The objective of this study was to characterize the response to an aerosolized lysate of killed bacteria, as a basis for studying the regulation and in vivo effects of these inducible innate immune responses. RESULTS:Bacterial lysate consisting of heat-killed and sonicated Staphylococcus aureus and Escherichia coli was aerosolized to 6 calves and systemic and pulmonary innate immune and inflammatory responses were measured in the first 24?h relative to baseline. Evaluated parameters included clinical parameters (body temperature and heart and respiratory rates), blood acute phase proteins and leukocyte counts, and leukocytes and proteins in bronchoalveolar lavage fluid. Mild clinical signs with increased heart rates and rectal temperatures developed following administration of the lysate, with resolution by 24?h. Serum haptoglobin and plasma fibrinogen concentrations were elevated at 24?h relative to baseline. Bronchoalveolar lavage fluid (BALF) had increased cellularity and increased proportion of neutrophils, as well as higher concentrations of interleukin (IL)-8, IL-10 and total protein at 24?h relative to baseline. Mass spectrometry identified 965 unique proteins in BALF: 19 proteins were increased and 26 proteins were decreased relative to baseline. The upregulated proteins included those involved in innate immunity including activation of complement, neutrophils and platelets. At postmortem examination, calves receiving higher doses of lysate had areas of lobular consolidation and interlobular edema. Histologically, neutrophils were present within bronchioles and to a lesser extent within alveoli. Calves receiving highest doses of lysate had patchy areas of neutrophils, hemorrhage and hyaline membranes within alveoli. CONCLUSIONS:Aerosolization of bacterial lysate stimulated an innate immune response in lungs and airways, with alveolar damage observed at higher doses. Such a stimulus could be of value for investigating the effects of inducible innate immune responses on occurrence of disease, or for evaluating how stress, drugs or genetics affect these dynamic responses of the respiratory tract.

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Dataset Information

Effect of aerosolized bacterial lysate on development of naturally occurring respiratory disease in beef calves.

Background

Hypothesis

Animals

Methods

Results

Conclusions and clinical importance

Publications

Effect of aerosolized bacterial lysate on development of naturally occurring respiratory disease in beef calves.

Similar Datasets

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