Respiratory Tract Infections In Cattle Research Articles

Genetic Organization of Acquired Antimicrobial Resistance Genes and Detection of Resistance-Mediating Mutations in a Gallibacterium anatis Isolate from a Calf Suffering from a Respiratory Tract Infection

Gallibacterium (G.) anatis isolates associated with respiratory diseases in calves and harboring acquired antimicrobial resistance genes have been described in Belgium. The aim of this study was to analyze the genetic organization of acquired resistance genes in the G. anatis isolate IMT49310 from a German calf suffering from a respiratory tract infection. The isolate was submitted to antimicrobial susceptibility testing, and a closed genome was obtained by a hybrid assembly of Illumina MiSeq short-reads and MinION long-reads. Isolate IMT49310 showed elevated MIC values for macrolides, aminoglycosides, florfenicol, tetracyclines, and trimethoprim/sulfamethoxazole. The acquired resistance genes catA1, floR, aadA1, aadB, aphA1, strA, tet(M), tet(B), erm(B), and sul2 were identified within three resistance gene regions in the genome, some of which were associated with IS elements, such as ISVsa5-like or IS15DII. Furthermore, nucleotide exchanges within the QRDRs of gyrA and parC, resulting in amino acid exchanges S83F and D87A in GyrA and S80I in ParC, were identified. Even if the role in the pathogenesis of respiratory tract infections in cattle needs to be further investigated, the identification of a G. anatis isolate with reduced susceptibility to regularly used antimicrobial agents in cases of fatal bovine respiratory tract infections is worrisome, and such isolates might also act as a reservoir for antimicrobial resistance genes.

Storage time and temperature affect the isolation rate of Mannheimia haemolytica and Pasteurella multocida from bovine bronchoalveolar lavage samples

BackgroundA microbiological diagnosis is essential to better target antimicrobial treatment, control and prevention of respiratory tract infections in cattle. Under field conditions, non-endoscopic broncho-alveolar lavage (nBAL) samples are increasingly collected. To what extent the highly variable turnaround time and storage temperatures between sampling and cultivation affect the isolation rate of bacterial pathogens is unknown. Therefore, the objective of this experimental study was to determine the effect of different storage temperatures (0 °C, 8 °C, 23 °C and 36 °C) and times (0,2,4,6,8,24,48 h) on the isolation rate and concentration of Pasteurellaceae in nBAL samples from clinically affected animals.ResultsAt a storage temperature temperature of 36 °C isolation rates of Mannheimia haemolytica and Pasteurella multocida were significantly reduced 6 h and 48 h after sampling, respectively. At room temperature (23 °C), a decrease in M. haemolytica and P. multocida isolation rate was noticed, starting at 24 and 48 h after sampling, respectively, but only significant for P. multocida at 48 h. The presence of microbial contamination negatively affected the isolation of P. multocida in clinical nBAL samples, but not of M. haemolytica.ConclusionOptimal M. haemolytica and P. multocida isolation rates from clinical nBAL samples are obtained after storage at 0 °C or 8 °C, provided that the sample is cultivated within 24 h after sampling. The maximum period a sample can be stored without an effect on the M. haemolytica and P. multocida isolation success varies and is dependent on the storage temperature and the degree of microbial contamination.

Non-specific protection from respiratory tract infections in cattle generated by intranasal administration of an innate immune stimulant.

Alternatives to antibiotics for prevention of respiratory tract infections in cattle are urgently needed given the increasing public and regulatory pressure to reduce overall antibiotic usage. Activation of local innate immune defenses in the upper respiratory tract is one strategy to induce non-specific protection against infection with the diverse array of viral and bacterial pathogens associated with bovine respiratory disease complex (BRDC), while avoiding the use of antibiotics. Our prior studies in rodent models demonstrated that intranasal administration of liposome-TLR complexes (LTC) as a non-specific immune stimulant generated high levels of protection against lethal bacterial and viral pathogens. Therefore, we conducted studies to assess LTC induction of local immune responses and protective immunity to BRDC in cattle. In vitro, LTC were shown to activate peripheral blood mononuclear cells in cattle, which was associated with secretion of INFγ and IL-6. Macrophage activation with LTC triggered intracellular killing of Mannheimia hemolytica and several other bacterial pathogens. In studies in cattle, intranasal administration of LTC demonstrated dose-dependent activation of local innate immune responses in the nasopharynx, including recruitment of monocytes and prolonged upregulation (at least 2 weeks) of innate immune cytokine gene expression by nasopharyngeal mucosal cells. In a BRDC challenge study, intranasal administration of LTC prior to pathogen exposure resulted in significant reduction in both clinical signs of infection and disease-associated euthanasia rates. These findings indicate that intranasal administration of a non-specific innate immune stimulant can be an effective method of rapidly generating generalized protection from mixed viral and bacterial respiratory tract infections in cattle.

RESPIRATORY TRACT INFECTIONS IN CATTLE

In the article a literature review of Bovine respiratory diseases (BRD) is presented. Respiratory diseases are considered to be one of the most harmful diseases of cattle, which cause great economic damage for the operators of the cattle industry. The BRD complex is a multifactorial and multi-etiological disease. The BRD complex is a multifactorial and multi-etiological disease. The main factors providing the BRD development are the management status of rearing cattle, the impact of the environment and pathogens. Without neglecting the importance of the first two factors, pathogenic microorganisms remain the major etiological factor of BRD. Respiratory tract infections in cattle are caused by viruses and bacteria, moreover the diseases often develop in an associated form. However, the bacterial factor in the etiology of respiratory diseases plays a main role. Mannheimia haemolytica serotype 1 is the main pathogen of BRD, which can cause disease as a single etiologic agent and as in association with other pathogens (Histophilus somni, Mycoplasma bovis). In most cases, fibrinous pneumonia or fatal acute pneumonia is often associated with Mannheimia haemolytica. Pasteurella multocida is considered to be a less virulent bacteria than Mannheimia haemolytica, and for a higher level of infection need to initiate the inflammatory process in the respiratory tract of animals. Pathogenic strains of Pasteurella multocida serogroup A are a significant etiologic factor of severe enzootic pneumonia in dairy calves. Respiratory diseases caused by mycoplasma remain one of the serious infectious diseases of cattle. Mycoplasma bovis is the most invasive and dangerous mycoplasma for young cattle. This type of mycoplasma is usually present in the upper respiratory tract of clinically healthy calves who are bacterial carriers. When the zootechnical conditions of brieding and feeding the calves are disturbed and for other stress factors there is an active proliferation of mycoplasmas and they successfully colonize the lower respiratory tract of the animals, causing an inflammatory process in the lungs. Other commensal bacteria of the upper respiratory tract, Histophilus somni, can cause pneumonia that usually occurs in subacute or chronic form. The pathogenic forms of this bacteria are often isolated together with Mannheimia hemolytica. Other opportunistic bacteria (Arcanobacterium pyogenes, Streptococcus pneumoniae, Staphylococcus aureus, Chlamydiales spp., Fusobacterium necrophorum, Corynebacterium bovis) may be etiological factors for the development of BRD. Depending on the etiologic agent, the clinical symptoms of calf bronchopneumonia have some specificity, herewith the degree of lung damage depends on the duration of the disease and the virulence of the pathogen.

Mycoplasma infections in dairy cattle farms in Turkey

Mycoplasmas cause the most severe and economically costly diseases of cattle throughout the world. In this study, Mycoplasma species were isolated from calves and cows with suspected mycoplasmosis in Holstein dairy cattle farms within 7 geographical regions of Turkey between May 2010 and December 2015. Mycoplasma infections were positive in 17 (80.9%) of 21 dairy cattle farms and the overall percentage was calculated as 32.1%. The highest isolation rate occurred in the Southeastern Anatolia Region (42.8%), and the lowest was observed in the Mediterranean Region (19.6%). In total, 172 Mycoplasma spp. were isolated from samples. Using PCR analysis, 149 (87.6%) isolates were identified as Mycoplasma bovis (M. bovis). Eleven (6.3%) isolates were identified as M. alkalescens, 2 (1.1%) were M. canis, and 10 (5.8%) were M. bovigenitalium. The isolation rate was found to be increasing annually. In conclusion, mycoplasmosis is a common problem in Holstein dairy cattle farms in Turkey, and M. bovis is the most frequently encountered cause of mycoplasma infections. The isolation rate seems to have increased in correlation with increased live cattle imports. Additionally, M. alkalescens and M. canis were isolated and identified in respiratory tract infections in cattle from Turkey for the first time.

A new approach for diagnosis of bovine coronavirus using a reverse transcription recombinase polymerase amplification assay

Bovine coronavirus (BCoV) is an economically significant cause of calf scours and winter dysentery of adult cattle, and may induce respiratory tract infections in cattle of all ages. Early diagnosis of BCoV helps to diminish its burden on the dairy and beef industry. Real-time RT-PCR assay for the detection of BCoV has been described, but it is relatively expensive, requires well-equipped laboratories and is not suitable for on-site screening. A novel assay, using reverse transcription recombinase polymerase amplification (RT-RPA), for the detection of BCoV is developed. The BCoV RT-RPA was rapid (10–20min) and has an analytical sensitivity of 19 molecules. No cross-reactivity with other viruses causing bovine gastrointestinal and/or respiratory infections was observed. The assay performance on clinical samples was validated by testing 16 fecal and 14 nasal swab specimens and compared to real-time RT-PCR. Both assays provided comparable results. The RT-RPA assay was significantly more rapid than the real-time RT-PCR assay. The BCoV RT-RPA constitutes a suitable accurate, sensitive and rapid alternative to the common measures used for BCoV diagnosis. In addition, the use of a portable fluorescence reading device extends its application potential to use in the field and point-of-care diagnosis.

Inhibition of Protein Synthesis on the Ribosome by Tildipirosin Compared with Other Veterinary Macrolides

Tildipirosin is a 16-membered-ring macrolide developed to treat bacterial pathogens, including Mannheimia haemolytica and Pasteurella multocida, that cause respiratory tract infections in cattle and swine. Here we evaluated the efficacy of tildipirosin at inhibiting protein synthesis on the ribosome (50% inhibitory concentration [IC(50)], 0.23 ± 0.01 μM) and compared it with the established veterinary macrolides tylosin, tilmicosin, and tulathromycin. Mutation and methylation at key rRNA nucleotides revealed differences in the interactions of these macrolides within their common ribosomal binding site.

A novel Erm monomethyltransferase in antibiotic‐resistant isolates of Mannheimia haemolytica and Pasteurella multocida

Mannheimia haemolytica and Pasteurella multocida are aetiological agents commonly associated with respiratory tract infections in cattle. Recent isolates of these pathogens have been shown to be resistant to macrolides and other ribosome-targeting antibiotics. Direct analysis of the 23S rRNAs by mass spectrometry revealed that nucleotide A2058 is monomethylated, consistent with a Type I erm phenotype conferring macrolide-lincosamide resistance. The erm resistance determinant was identified by full genome sequencing of isolates. The sequence of this resistance determinant, now termed erm(42), has diverged greatly from all previously characterized erm genes, explaining why it has remained undetected in PCR screening surveys. The sequence of erm(42) is, however, completely conserved in six independent M. haemolytica and P. multocida isolates, suggesting relatively recent gene transfer between these species. Furthermore, the composition of neighbouring chromosomal sequences indicates that erm(42) was acquired from other members of the Pasteurellaceae. Expression of recombinant erm(42) in Escherichia coli demonstrated that the enzyme retains its properties as a monomethyltransferase without any dimethyltransferase activity. Erm(42) is a novel addition to the Erm family: it is phylogenetically distant from the other Erm family members and it is unique in being a bona fide monomethyltransferase that is disseminated between bacterial pathogens.

Antibacterial activity of Helleborus bocconei Ten. subsp. siculus root extracts

Aim of the study Roots of Helleborus bocconei Ten. subsp. siculus (Schiffner) Merxm. & Podl. are widely used in veterinary folk medicine in Sicily (Italy) to diagnose and cure lower respiratory tract infections in cattle. This study intended to evaluate the in vitro antibacterial activity of the methanolic root extract of Helleborus bocconei Ten. subsp. siculus, and of the bufadienolide and ecdysteroid fractions extracted from its roots, against strains belonging to species commonly associated with respiratory tract infections. Materials and methods The phytochemical screening of the previously prepared plant extracts was carried out by chemical, thin-layer chromatography and spectroscopic methods. The in vitro antibacterial activity of the extracts against seven different standard bacterial strains was evaluated by broth microdilution. Results According to the present study, Helleborus bocconei Ten. subsp. siculus roots contain bufadienolides and ecdysteroids, and the extracts containing these compounds, as well as the crude methanolic root extract, show antibacterial activity against microorganisms responsible for respiratory infections. In particular, the bufadienolide extract has the highest inhibitory activity against all the tested organisms, and, as the other extracts, shows the lowest MIC values (100 μg/ml) against Moraxella catarrhalis and Streptococcus pneumoniae. Conclusions Since the roots of Helleborus bocconei Ten. subsp. siculus contain substances with antibacterial activity, the traditional use of this plant may also derive from its antibacterial properties.

Molecular characterization of Bovine herpesvirus type 1 Indonesian isolates

Different subtypes of bovine herpesvirus 1 (BHV-1) have been associated with different clinical conditions of cattle. For that reason subtypes differentiation has become an essential tool for understanding the pathogenesis and epidemiology of BHV infections. In search for a genomic region that would allow a clear distinction between BHV-1.1 and BHV-1.2 of glycoprotein D (gD) genes of 8 Indonesian isolates were amplified and sequenced. The amino acid sequence alignments revealed that the levels of genomic similarity ranging from 98.8 to 100% among BHV-1 Indonesian isolates and its results were also similar between BHV-1 Indonesia isolates and BHV-1.1 reference, and 98.4 to 98.8% between BHV-1 Indonesian isolates and BHV-1.2 reference. The isolates could be clearly separated into BHV-1.1 and BHV-1.2 after phylogenetic analysis. The results showed that the Indonesian isolates were characterized as BHV-1.1 as agent caused respiratory tract infections in cattle or infectious bovine rhinotracheitis (IBR) disease. The results suggest that the phylogenetic analysis performed here can be used as a potential molecular epidemiological tool for herpesviruses. Key Words : BHV-1.1, BHV-1.2, Glycoprotein D, Phylogenetic Analysis, IBR

Coronavirus isolation from nasal swab samples in cattle with signs of respiratory tract disease after shipping

Objective To monitor the prevailing viral respiratory tract infections in cattle after transportation to feedlots. Animals 100 cattle with signs of respiratory tract disease on arrival at 2 feedlots. Procedures Nasal swab samples were obtained from each animal and were used for inoculation of defined cell culture systems that detected bovine viruses known to cause respiratory tract infections, as well as viruses previously not recognized as respiratory pathogens for cattle. Results Bovine respiratory coronaviruses were isolated from 38 of the 100 cattle, including 6 of 50 cattle from California, 22 of 31 cattle from Oklahoma, 6 of 11 cattle from Texas, and 4 of 8 cattle of unknown origin. Parainfluenza 3 viruses also were isolated from 4 California cattle, but other bovine viruses were not detected. Clinical Implications The high rate of coronavirus isolations from feedlot cattle with signs of respiratory tract disease implied wide distribution and high susceptibility among cattle to this infection, which had not been detected by use of viral isolation systems in previous etiologic evaluations of feedlot cattle affected with bovine respiratory disease complex. (J Am Vet Med Assoc 1996; 208:1452-1455)