Contribution of the Mucosal Microbiota to Bovine Respiratory Health

Zeineldin, Mohamed; Lowe, James; Aldridge, Brian

doi:10.1016/j.tim.2019.04.005

Cited by 73 publications

(91 citation statements)

References 82 publications

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“…In this model, the bacterial composition of the lung is determined more by the constant flow of transient bacteria than the replication of resident bacteria [17,23]. Foreign bacteria are constantly migrating into the respiratory tract through a combination of inhalation, aerosolized saliva microaspiration, and dispersion along mucosal surfaces [19,[24][25][26]. At the same time, these bacteria are also being constantly cleared from the respiratory tract by forced exhalation (coughing/sneezing) and host respiratory defenses (i.e.…”

Section: Discussionmentioning

confidence: 99%

Topography of the respiratory tract bacterial microbiota in cattle

McMullen

Alexander

Léguillette

et al. 2020

Preprint

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BackgroundBacterial bronchopneumonia (BP) is the leading cause of morbidity and mortality in cattle. While the bacterial composition of the bovine upper respiratory tract (URT) has not been studied in detail, the nasopharynx is generally accepted as the primary source of pathogenic bacteria that cause BP.However, it has recently been shown in humans that the oropharynx may act as the primary reservoir for pathogens that reach the lung. The objective was therefore to describe the bacterial microbiota present along the entire cattle respiratory tract to determine which URT niches may contribute the most to the composition of the lung microbiota. MethodsSeventeen upper and lower respiratory tract locations were sampled from 15 healthy feedlot steer calves. Samples were collected using a combination of swabs, protected specimen brushes, and saline washes. DNA was extracted from each sample and the 16S rRNA gene (V3-V4) was sequenced.Community composition, alpha-diversity, and beta-diversity were compared among sampling locations. ResultsMicrobiota composition differed across sampling locations, with physiologically and anatomically distinct locations showing different relative abundances of 1,137 observed sequence variants (SVs).An analysis of similarities showed that the lung was more similar to the nasopharynx (R-statistic = 0.091) than it was to the oropharynx (R-statistic = 0.709) or any other URT sampling location. Five distinct metacommunities were identified across all samples after clustering at the genus level using Dirichlet multinomial mixtures. This included a metacommunity found primarily in the lung and nasopharynx that was dominated by Mycoplasma . Further clustering at the SV level showed a shared metacommunity between the lung and nasopharynx that was dominated by Mycoplasma dispar .Other metacommunities found in the nostrils, tonsils, and oral microbiotas were dominated by Moraxella , Fusobacterium , and Streptococcus , respectively.

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Section: Discussionmentioning

confidence: 99%

Topography of the respiratory tract bacterial microbiota in cattle

McMullen

Alexander

Léguillette

et al. 2020

Preprint

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“…Increasing evidence indicates that commensal members of the bovine respiratory microbiota have competitive relationships with opportunistic pathogens and may be involved in a microbiota-mediated defense against respiratory infection (18,20,22). Therefore, we recently screened commensal bacteria (n ϭ 178) isolated from the respiratory tract of healthy cattle for the development of intranasal BT to mitigate the BRD pathogen M. haemolytica, as an alternative to metaphylactic antimicrobial use.…”

Section: Discussionmentioning

confidence: 99%

“…Increasing evidence indicates that commensal bacteria in the bovine nasopharynx may prevent the colonization and proliferation of bacterial pathogens through a variety of mechanisms, including direct antagonism (i.e., antimicrobial properties), competition for nutrients and adhesion sites, and host immunomodulatory effects (15)(16)(17)(18). Among commensal bacteria, lactic acid-producing bacteria (LAB), and more specifically Lactobacillus spp., may be important in providing colonization resistance against bacterial respiratory pathogens (19)(20)(21).…”

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confidence: 99%

Intranasal Bacterial Therapeutics Reduce Colonization by the Respiratory Pathogen Mannheimia haemolytica in Dairy Calves

et al. 2020

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Six Lactobacillus strains originating from the nasopharyngeal microbiota of cattle were previously characterized in vitro and identified as candidate bacterial therapeutics (BTs) for mitigating the bovine respiratory pathogen Mannheimia haemolytica. In the present study, these BT strains were evaluated for their potential to (i) reduce nasal colonization by M. haemolytica, (ii) modulate the nasal microbiota, and (iii) stimulate an immune response in calves experimentally challenged with M. haemolytica. Twenty-four Holstein bull calves (1 to 3 weeks old) received either an intranasal BT cocktail containing 6 Lactobacillus strains (3 × 109 CFU per strain; BT + Mh group) 24 h prior to intranasal M. haemolytica challenge (3 × 108 CFU) or no BTs prior to challenge (Mh, control group). Nasal swab, blood, and transtracheal aspiration samples were collected over the course of 16 days after BT inoculation. Counts of M. haemolytica were determined by culturing, and the nasal and tracheal microbiotas were evaluated using 16S rRNA gene sequencing. Serum cytokines (interleukin-6 [IL-6], IL-8, and IL-10) were quantified by enzyme-linked immunosorbent assay (ELISA). Administration of BT reduced nasal colonization by M. haemolytica (P = 0.02), modified the composition and diversity of the nasal microbiota, and altered interbacterial relationships among the 10 most relatively abundant genera. The BT + Mh calves also had a lower relative abundance of Mannheimia in the trachea (P < 0.01) but similar cytokine levels as Mh calves. This study demonstrated that intranasal BTs developed from the bovine nasopharyngeal Lactobacillus spp. were effective in reducing nasal colonization by M. haemolytica in dairy calves. IMPORTANCE Bovine respiratory disease (BRD) is one of the significant challenges for the modern dairy industry in North America, accounting for 23 to 47% of the total mortality among pre- and postweaned dairy heifers. Mass medication with antibiotics is a common practice to control BRD in dairy cattle. However, the emergence of multidrug-resistant BRD pathogens highlights the importance of developing alternatives to antibiotics for BRD mitigation. Using a targeted approach, we recently identified 6 Lactobacillus strains originating from the bovine respiratory microbiota as candidates to be used as bacterial therapeutics (BTs) for the mitigation of the BRD pathogen Mannheimia haemolytica. Here, we demonstrated that intranasal inoculation of the BT strains reduced nasal colonization by M. haemolytica in dairy calves experimentally challenged with this pathogen. This study, for the first time, shows the potential use of intranasal BTs as an alternative to mitigate BRD pathogens in cattle.

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“…The microbiome-gut-immune-brain axis maintains the health of all animals. 13,[26][27][28][29][30][31][32] As the calf develops there is a succession of microbes that finally culminates in what is called a "climax" community that occurs as the GIT transitions to an anaerobic environment. 29,33 This succession is influenced by nutrition, stress, and environment.…”

Section: Microbiome and Enteric Immunitymentioning

confidence: 99%

“…7). 26 This lowers the defenses against pathogen entry, leading to increased risk of disease. This leads to dysbiosis, the loss of good bacteria with an overgrowth of harmful organisms (see Fig.…”

Section: Microbiome and Enteric Immunitymentioning

confidence: 99%

Mucosal Immune System of Cattle

Chase

Kaushik

2019

Veterinary Clinics of North America: Food Animal Practice

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KEYWORDS Bovine Mucosal Immunology Gastrointestinal Respiratory Reproductive Microbiome KEY POINTSThe largest organ of the immune system is the mucosa making the management of it essential for productivity and health. The mucosal barrier consists of mucous, antimicrobial peptides, and IgA and is a "kill zone" to prevent microbial invasion of the epithelium. The mucosal epithelial cells are key cells that maintain the "kill zone" and "mucosal firewall" and respond to metabolites and microbial components from the lumen and signals from immune cells to maintain tight junctions and prevent leaky gut. The mucosal immune system has a unique circulatory system where immune cells that have activated in mucosal region recirculate to mucosal regions, a system termed the common mucosal system.

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Contribution of the Mucosal Microbiota to Bovine Respiratory Health

Cited by 73 publications

References 82 publications

Topography of the respiratory tract bacterial microbiota in cattle

Topography of the respiratory tract bacterial microbiota in cattle

Intranasal Bacterial Therapeutics Reduce Colonization by the Respiratory Pathogen Mannheimia haemolytica in Dairy Calves

Mucosal Immune System of Cattle

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