Dataset Information

Does swab type matter? Comparing methods for Mannheimia haemolytica recovery and upper respiratory microbiome characterization in feedlot cattle.

ABSTRACT:

Background

Bovine respiratory disease (BRD) is caused by interactions among host, environment, and pathogens. One standard method for antemortem pathogen identification in cattle with BRD is deep-guarded nasopharyngeal swabbing, which is challenging, costly, and waste generating. The objective was to compare the ability to recover Mannheimia haemolytica and compare microbial community structure using 29.5 inch (74.9 cm) deep-guarded nasopharyngeal swabs, 16 inch (40.6 cm) unguarded proctology swabs, or 6 inch (15.2 cm) unguarded nasal swabs when characterized using culture, real time-qPCR, and 16S rRNA gene sequencing. Samples for aerobic culture, qPCR, and 16S rRNA gene sequencing were collected from the upper respiratory tract of cattle 2 weeks after feedlot arrival.

Results

There was high concordance of culture and qPCR results for all swab types (results for 77% and 81% of sampled animals completely across all 3 swab types for culture and qPCR respectively). Microbial communities were highly similar among samples collected with different swab types, and differences identified relative to treatment for BRD were also similar. Positive qPCR results for M. haemolytica were highly concordant (81% agreed completely), but samples collected by deep-guarded swabbing had lower amounts of Mh DNA identified (Kruskal-Wallis analysis of variance on ranks, P < 0.05; Dunn-test for pairwise comparison with Benjamini-Hochberg correction, P < 0.05) and lower frequency of positive compared to nasal and proctology swabs (McNemar's Chi-square test, P < 0.05).

Conclusions

Though differences existed among different types of swabs collected from individual cattle, nasal swabs and proctology swabs offer comparable results to deep-guarded nasopharyngeal swabs when identifying and characterizing M. haemolytica by culture, 16S rRNA gene sequencing, and qPCR.

SUBMITTER: Crosby WB

PROVIDER: S-EPMC9375289 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature

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Publications

Does swab type matter? Comparing methods for Mannheimia haemolytica recovery and upper respiratory microbiome characterization in feedlot cattle.

Crosby William B WB Pinnell Lee J LJ Richeson John T JT Wolfe Cory C Castle Jake J Loy John Dustin JD Gow Sheryl P SP Seo Keun Seok KS Capik Sarah F SF Woolums Amelia R AR Morley Paul S PS

Animal microbiome 20220813 1

<h4>Background</h4>Bovine respiratory disease (BRD) is caused by interactions among host, environment, and pathogens. One standard method for antemortem pathogen identification in cattle with BRD is deep-guarded nasopharyngeal swabbing, which is challenging, costly, and waste generating. The objective was to compare the ability to recover Mannheimia haemolytica and compare microbial community structure using 29.5 inch (74.9 cm) deep-guarded nasopharyngeal swabs, 16 inch (40.6 cm) unguarded proct ...[more]

PMID: 35964128

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Project description:Bacterial pneumonia causes significant economic loss to the beef industry and occurs at times of stress and viral infection. Administering antibiotics to at-risk calves is often used to prevent the disease, but alternatives to mass treatment with antibiotics are needed. Tracheal antimicrobial peptide (TAP), a β-defensin naturally produced by bovine airways, has bactericidal activity against the pathogens that cause pneumonia in cattle. However, TAP expression is suppressed by glucocorticoid (stress) and viral infection. We hypothesized that delivering TAP to the respiratory tract would prevent development of pneumonia in calves infected with Mannheimia haemolytica. Clean-catch calves (i.e. obtained prior to contact with the dam) were challenged by aerosol with M. haemolytica, and TAP or water was delivered to the respiratory tract at 0.3, 2 and 6 hours post-infection. TAP treatment did not protect against development of disease. Calves treated with TAP had similar bacterial loads in the nasal cavity and lung compared to calves treated with water. Similarly, TAP treatment did not affect the development of clinical signs, elevated rectal temperatures, or increased levels of blood neutrophils, haptoglobin and fibrinogen that occurred after bacterial challenge. Postmortem gross and histologic lung lesions were also similar in the two groups. To determine why there was a lack of protective effect, we tested the effect of substances in respiratory lining fluid on the bactericidal activity of TAP. Physiologic concentrations of sodium chloride inhibited TAP bactericidal activity in vitro, as did serum at concentrations of 0.62 to 2.5%, but concentrated bronchoalveolar lavage fluid had no consistent effect. These findings suggest that TAP does not have in vivo bactericidal activity against M. haemolytica because of interference by physiological sodium chloride levels and by serum. Thus, administration of TAP may not be effective for prevention of M. haemolytica pneumonia.

Dataset Information

Does swab type matter? Comparing methods for Mannheimia haemolytica recovery and upper respiratory microbiome characterization in feedlot cattle.

Background

Results

Conclusions

Publications

Does swab type matter? Comparing methods for Mannheimia haemolytica recovery and upper respiratory microbiome characterization in feedlot cattle.

Similar Datasets

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