-
Veterinary Microbiology Jan 2024Mannheimia haemolytica is known as one of the major bacterial contributors to Bovine Respiratory Disease (BRD) syndrome. This study sought to establish a novel...
Mannheimia haemolytica is known as one of the major bacterial contributors to Bovine Respiratory Disease (BRD) syndrome. This study sought to establish a novel species-specific PCR to aid in identification of this key pathogen. As well, an existing multiplex PCR was used to determine the prevalence of serovars 1, 2 or 6 in Australia. Most of the 65 studied isolates originated from cattle with a total of 11 isolates from small ruminants. All problematic field isolates in the identification or serotyping PCRs were subjected to whole genome sequencing and bioinformatic analysis. The field isolates were also subjected to rep-PCR fingerprinting. A total of 59 out of the 65 tested isolates were conformed as M. haemolytica by the new species-specific PCR which is based on the rpoB gene. The confirmed M. haemolytica field isolates were assigned to serovars 1 (24 isolates), 2 (seven isolates) and 6 (26 isolates) while two of the isolates were negative in the serotyping PCR. The two non-typeable isolates were assigned to serovar 7 and 14 following whole genome sequencing and bioinformatic analysis. The rep-PCR typing resulted in five major clusters with serovars 1 and 6 often within the same cluster. The M. haemolytica-specific PCR developed in this work was species specific and should be a valuable support for frontline diagnostic laboratories. The serotyping results support the relative importance of serovars 1 and 6 in bovine respiratory disease.
Topics: Cattle; Animals; Mannheimia haemolytica; Bacteria; Serotyping; Cattle Diseases; Ruminants; Multiplex Polymerase Chain Reaction; Respiratory Tract Diseases
PubMed: 38086163
DOI: 10.1016/j.vetmic.2023.109930 -
Veterinary Microbiology Aug 2023Amongst the bacterial pathogens associated with the bovine respiratory disease syndrome (BRD) in cattle are Mannheimia haemolytica and Mycoplasma bovis. The interaction...
Amongst the bacterial pathogens associated with the bovine respiratory disease syndrome (BRD) in cattle are Mannheimia haemolytica and Mycoplasma bovis. The interaction between these two pathogens has not been investigated before; thus, there are gaps in the knowledge of why and how a previous infection with M. haemolytica allows the development of M. bovis-related lesions. We hypothesized that upon M. haemolytica infection, inflammatory products are produced in the lung and that these inflammatory products stimulate M. bovis to produce proteases and lipases that degrade lipids and proteins important for lung function. In this work, we identified several M. bovis proteases and lipases whose expression was modulated by M. haemolytica products in vitro. We performed co-infection animal challenges to develop a model to test vaccine protection. A prior exposure to BHV-1 followed by infection with M. bovis and M. haemolytica resulted in severe pathology and the BHV-1 infection was abandoned. When M. bovis and M. haemolytica were introduced into the lungs by bronchoscopy, we found that M. haemolytica resulted in worsening of the respiratory disease caused by M. bovis. We performed a proof-of-concept trial where animals were immunized with the M. bovis proteins identified in this study and challenged with both pathogens. Despite detecting significant humoral immune responses to the antigens, the experimental vaccine failed to protect against M. bovis disease.
Topics: Animals; Cattle; Bacteria; Cattle Diseases; Mannheimia haemolytica; Mycoplasma bovis; Respiratory Tract Diseases; Proof of Concept Study
PubMed: 37276814
DOI: 10.1016/j.vetmic.2023.109793 -
Journal of Advanced Veterinary and... Sep 2023This research aimed to assess the prevalence of caprine pasteurellosis, isolate and identify pasteurellosis ( and ) in pneumonic goats, and discover the main bacterial... (Review)
Review
OBJECTIVE
This research aimed to assess the prevalence of caprine pasteurellosis, isolate and identify pasteurellosis ( and ) in pneumonic goats, and discover the main bacterial cause of pneumonia.
MATERIALS AND METHODS
One hundred and five samples (94 nasal swabs and 11 lung tissues) from goats suspected of having pneumonia were taken and transferred aseptically to the laboratory. Following the processing of the collected samples, spp. was isolated with the aid of plate culture methods. Biochemical characteristics were used to identify all bacterial isolates, which were then verified by polymerase chain reaction (PCR). Antimicrobial susceptibility testing was also carried out to evaluate the sensitivity profiles of various antibiotics. The serotype-specific antigen (PHSSA) gene was used to identify isolates of , and the KMT1 gene was used to identify isolates of .
RESULTS
From the 105 clinically suspicious samples, 51 (48.57%) were identified to be through bacteriological testing and also by PCR targeting the gene. Of these, 47.87% (45/94) were nasal swabs, and 54.55% (6/11) were lung tissues. Among confirmed samples, 70.59% (36/51) were identified as and 29.41% (15/51) were identified as . Resistance to tetracycline, streptomycin, oxytetracycline, gentamicin, and ceftriaxone was found in 50%-83% of the isolates. In addition, PCR identified the PHSSA and KMT1 genes from isolates of and , respectively.
CONCLUSION
The present study revealed that and primarily caused pasteurellosis in pneumonic goats in Bangladesh. However, when treating these animals, the proper choice of antimicrobials should be made to control this disease.
PubMed: 37969786
DOI: 10.5455/javar.2023.j707 -
Veterinary Pathology Mar 2024-associated abomasitis has been clinically described as a cause of sudden death in lambs, but it is poorly characterized. We describe the pathological features of a...
-associated abomasitis has been clinically described as a cause of sudden death in lambs, but it is poorly characterized. We describe the pathological features of a severe fibrinonecrotizing abomasitis in 3 lambs that died suddenly. All 3 abomasums had a thickened submucosa due to edema and necrotic areas delimited by bands of degenerate neutrophils with slender nuclei (oat cells) and angiocentric distributions. The overlying mucosa was congested. Myriads of gram-negative coccobacilli were observed within the oat cell bands. was isolated from the abomasum in all 3 animals and was serotyped as A2 in one of them. Pericarditis and pleuritis were observed in 2 of the lambs. spp. were isolated in 1 lamb and detected by immunohistochemistry in the 3 animals, suggesting clostridial co-infection. should be considered among the differential diagnoses of necrotizing abomasitis in lambs.
PubMed: 38440930
DOI: 10.1177/03009858241235393 -
PloS One 2024Mannheimia haemolytica is the principal agent contributing to bovine respiratory disease and can form biofilms with increased resistance to antibiotic treatment and host...
Mannheimia haemolytica is the principal agent contributing to bovine respiratory disease and can form biofilms with increased resistance to antibiotic treatment and host immune defenses. To investigate the molecular mechanisms underlying M. haemolytica biofilm formation, transcriptomic analyses were performed with mRNAs sequenced from planktonic and biofilm cultures of pathogenic serotypes 1 (St 1; strain D153) and St 6 (strain D174), and St 2 (strain D35). The three M. haemolytica serotypes were cultured in two different media, Roswell Park Memorial Institute (RPMI) 1640 and brain heart infusion (BHI) to form the biofilms. Transcriptomic analyses revealed that the functions of the differentially expressed genes (DEGs) in biofilm associated cells were not significantly affected by the two media. A total of 476 to 662 DEGs were identified between biofilm associated cells and planktonic cells cultured under BHI medium. Functional analysis of the DEGs indicated that those genes were significantly enriched in translation and many biosynthetic processes. There were 234 DEGs identified in St 1 and 6, but not in St 2. The functions of the DEGs included structural constituents of ribosomes, transmembrane proton transportation, proton channels, and proton-transporting ATP synthase. Potentially, some of the DEGs identified in this study provide insight into the design of new M. haemolytica vaccine candidates.
Topics: Animals; Cattle; Mannheimia haemolytica; Plankton; Protons; Biofilms; Cattle Diseases; Gene Expression Profiling
PubMed: 38329985
DOI: 10.1371/journal.pone.0297692 -
Pathogens (Basel, Switzerland) May 2024Pradofloxacin-a dual-targeting fluoroquinolone-is the most recent approved for use in food animals. Minimum inhibitory and mutant prevention concentration values were...
Pradofloxacin-a dual-targeting fluoroquinolone-is the most recent approved for use in food animals. Minimum inhibitory and mutant prevention concentration values were determined for pradofloxacin, ceftiofur, enrofloxacin, florfenicol, marbofloxacin, tildipirosin, tilmicosin, and tulathromycin. For strains, MIC values were ≤0.016/≤0.016/≤0.016 and MPC values were 0.031/0.063/0.063; for strains, the MIC values ≤0.016/≤0.016/0.031 and MPC ≤ 0.016/0.031/0.063 for pradofloxacin. The pradofloxacin C/MIC and C/MPC values for and strains, respectively, were 212.5 and 53.9 and 212.5 and 109.7. Similarly, AUC/MIC and AUC/MPC for were 825 and 209.5, and for they were 825 and 425.8. Pradofloxacin would exceed the mutant selection window for >12-16 h. Pradofloxacin appears to have a low likelihood for resistance selection against key bovine respiratory disease bacterial pathogens based on low MIC and MPC values.
PubMed: 38787251
DOI: 10.3390/pathogens13050399 -
Veterinary Medicine (Auckland, N.Z.) 2023Pneumonic pasteurellosis is a respiratory system disease of sheep caused by , and responsible for the low productivity and economic loss resulting from death and...
Isolation and Molecular Detection of and from Clinically Pneumonic Pasteurellosis Cases of Bonga Sheep Breed and Their Antibiotic Susceptibility Tests in Selected Areas of Southwest Ethiopian Peoples Regional State, Ethiopia.
BACKGROUND
Pneumonic pasteurellosis is a respiratory system disease of sheep caused by , and responsible for the low productivity and economic loss resulting from death and treatment costs. This study was conducted to isolate and molecularly detect causative agents and antibiotic susceptibility tests from a nasal swab sample of the Bonga sheep breed that was suspected to have pneumonic pasteurellosis in selected areas of Southwest Ethiopian Peoples Regional State.
METHODS
A cross-sectional study design was used along with purposive sampling of nasal swab samples from sheep that were brought to veterinary clinics during the study period. Bacterial isolation and phenotypic characterization were carried out using microbiological and biochemical tests that followed standard microbiological techniques. To molecularly confirm the isolates, and , species-specific PCR primer genes were used. Using the disc diffusion method, molecularly confirmed isolates were subjected to an in vitro antibiotic susceptibility test.
RESULTS
The 85 samples that were scrutinized had an overall isolation rate of 31.76%, whereas the isolates of and had species compositions of 40.7% and 59.25%, respectively. Overall, 12.5% of the and 18.18% of the species were verified from phenotypical isolates using the species-specific PCR primer genes and , respectively. An in vitro antibiotic susceptibility test was carried out on all four PCR-confirmed isolates for seven commonly used antibiotics used to treat ovine pasteurellosis in the study area. It was found that both bacterial species were resistant to chloramphenicol and penicillin G.
CONCLUSION
Using phenotypic and molecular diagnostic techniques, the results of our current inquiry revealed that and are the causative agents of ovine pneumonic pasteurellosis in the study area.
PubMed: 38162823
DOI: 10.2147/VMRR.S435932 -
Veterinary Medicine and Science Jul 2023Small ruminants are the most numerous of man's domestic livestock. Although sheep represent a great resource for Ethiopia, the net rate of productivity per animal is...
Isolation and identification of Mannheimia haemolytica and Pasteurella multocida from symptomatic and asymptomatic sheep and their antibiotic susceptibility patterns in three selected districts of north Gondar zone, Gondar Ethiopia.
BACKGROUND
Small ruminants are the most numerous of man's domestic livestock. Although sheep represent a great resource for Ethiopia, the net rate of productivity per animal is very low due to many factors including respiratory disorders.
OBJECTIVES
The objectives of this work were to isolate and identify M. haemolytica and P. multocida as well as to assess the antibiotic susceptibility patterns of these isolates. Nasal swab samples were collected aseptically by using 70% alcohol as a disinfectant.
METHODS
A cross-sectional study was conducted in three selected districts of the north Gondar zone, Ethiopia.
RESULTS
From 148 samples collected in 94 (63.5%) asymptomatic and 54 (35.5%) symptomatic sheep, a total of 23 were isolated successfully based on cultural, staining, and biochemical characteristics. Of these isolates, 18 (78.3%) and 5 (21.7%) were M. haeimolytica and P. multocida, respectively. Compared with the total animals examined, the proportion of M. haeimolytica and P. multocida were 12.16 % (n = 18) and 3.38% (n = 5), respectively. All of the isolates were subjected to a panel of 8 antibiotic discs for sensitivity testing. Of the tested antibiotics, chloramphenicol (100%), gentamicin, and tetracycline (82.6%) each and co-trimoxazole (60.8%) were found to be the most effective drugs whereas, both species were completely resistant to vancomycin and showed a very low degree of susceptibility for the rest drugs.
CONCLUSIONS
In conclusion, M. haemolytica was found to be the predominant isolate in all host-related factors and most of the antibiotics were not fully effective against the isolates. Hence, treatment and/or vaccination of ovine pneumonic pasteurellosis should be emphasised to M. haeimolytica using the most effective drugs along with appropriate herd management practices.
Topics: Sheep; Animals; Mannheimia haemolytica; Pasteurella multocida; Ethiopia; Cross-Sectional Studies; Anti-Bacterial Agents
PubMed: 37197762
DOI: 10.1002/vms3.1166 -
Tropical Animal Health and Production Aug 2023The lipopolysaccharide (LPS) endotoxin and outer membrane protein (OMP) are among the virulence factors of Gram-negative bacteria responsible for inducing pathogenicity...
The lipopolysaccharide (LPS) endotoxin and outer membrane protein (OMP) are among the virulence factors of Gram-negative bacteria responsible for inducing pathogenicity in the infected host. OMP and LPS occur on the outer membrane of M. haemolytica A2, the primary aetiological agent of pneumonic mannheimiosis in small ruminants. While the LPS is known to mediate Gram-negative bacterial infection by activating downstream inflammatory pathways, the potential role of OMP during inflammatory responses remained unclear. Hence, this study determined the effect of the OMP of M. haemolytica A2 on the serum concentration of pro-inflammatory cytokines and the male reproductive hormones (testosterone and Luteinizing Hormone). We randomly assigned twelve bucks to three groups (n = 4 bucks each): Group 1 was challenged with 2 mL PBS buffer (pH 7.0) intranasally; Group 2 received 2 mL of 1.2 X 10 CFU/mL whole M. haemolytica A2 intranasally; and Group 3 received 2 mL of OMP extract obtained from 1.2 X 10 CFU/mL M. haemolytica A2 intramuscularly. Serum samples collected at pre-determined intervals were used for the quantitative determination of the pro-inflammatory cytokines (IL-1β, IL-6, and TNFα) and reproductive hormones (testosterone and LH) using commercial sandwich enzyme-linked immunosorbent assay (ELISA). The serum concentration of IL1β was initially increased within the first-hour post-challenge in Groups 2 and 3, followed by a significant decrease in concentration at 21d and 35d (p < 0.05) in Group 3. Only mild fluctuations in IL-6 occurred in group 2, as opposed to the 1.7-fold rapid increase in TNFα within 2 h post-challenge before decreasing at 6 h. An increase in pro-inflammatory cytokines was accompanied by an acute febrile response of 39.5 ± 0.38 °C (p < 0.05) at 2 h and 40.1 ± 0.29 °C (p < 0.05) at 4 h in Group 2 and Group 3, respectively. Serum testosterone decreased significantly (p < 0.05) in both treatment groups but remained significantly (p > 0.05) lower than in Group 1 throughout the study. There was a moderate negative association between testosterone and IL1β (r = -0.473; p > 0.05) or TNFα (r = -0.527; p < 0.05) in Group 2. Serum LH also showed moderate negative associations with TNFα in Group 2 (r = -0.63; p < 0.05) and Group 3 (r = -0.54; p > 0.05). The results of this study demonstrated that M. haemolytica A2 and its OMP produced marked alterations in serum levels of pro-inflammatory cytokines and male reproductive hormones. The negative correlations between serum testosterone and inflammatory cytokines would suggest the potential role of OMP in causing male infertility by mediating innate inflammatory responses to suppress testosterone production in bucks.
Topics: Male; Animals; Membrane Proteins; Cytokines; Tumor Necrosis Factor-alpha; Mannheimia haemolytica; Interleukin-6; Lipopolysaccharides; Testosterone
PubMed: 37589856
DOI: 10.1007/s11250-023-03706-0 -
Microbiology Spectrum Dec 2023The Gram-negative coccobacillus is a natural inhabitant of the upper respiratory tract in ruminants and the most common bacterial agent involved in bovine respiratory...
The Gram-negative coccobacillus is a natural inhabitant of the upper respiratory tract in ruminants and the most common bacterial agent involved in bovine respiratory disease complex development. Key virulence factors harbored by are leukotoxin, lipopolysaccharide, capsule, adhesins, and neuraminidase which are involved in evading innate and adaptive immune responses. In this study, we have shown that CMP-sialic acid synthetase () is necessary for the incorporation of sialic acid onto the membrane, and inactivation of results in increased phagocytosis and complement-mediated killing of thus demonstrating that sialylation contributes to the virulence of .
Topics: Cattle; Animals; Mannheimia haemolytica; N-Acylneuraminate Cytidylyltransferase; Serogroup; Gene Deletion; Phagocytosis
PubMed: 37850751
DOI: 10.1128/spectrum.02944-23