Effects of inflammatory stimuli on the development of Mycoplasma bovis pneumonia in experimentally challenged calves.

Many cattle infected with Mycoplasma bovis remain healthy while others develop severe chronic respiratory disease. We hypothesized that inflammatory stimuli such as co-pathogens worsen disease outcomes in M. bovis-infected calves. Calves (n=24) were intrabronchially inoculated with M. bovis and either killed bacterial lysate, transient M. haemolytica infection, or saline. Caseonecrotic lesions developed in 7/7 animals given M. haemolytica and M. bovis compared to 2/8 given M. bovis with no inflammatory stimulus, and 6/9 animals given bacterial lysate and M. bovis (P=0.01). Animals receiving M. haemolytica and M. bovis had more caseonecrotic foci in lungs than those receiving M. bovis with no inflammatory stimulus (median = 21 vs 0; P = 0.01), with an intermediate response (median = 5) in animals given bacterial lysate. In addition to caseonecrotic foci, infected animals developed neutrophilic bronchiolitis that appeared to develop into caseonecrotic foci, peribronchiolar lymphocytic cuffs that were not associated with the other lesions, and 4 animals with bronchiolitis obliterans. The data showed that transient lung inflammation at the time of M. bovis infection provoked the development of caseonecrotic bronchopneumonia, and the severity of inflammation influenced the number of caseonecrotic foci that developed. In contrast, caseonecrotic lesions were few or absent in M. bovis-infected calves without a concurrent inflammatory stimulus. These studies provide insight into how caseonecrotic lesions develop within the lung of M. bovis-infected calves. This and other studies suggest that controlling co-pathogens and harmful inflammatory responses in animals infected with M. bovis could potentially minimize development of M. bovis caseonecrotic bronchopneumonia.

Response to Oxidative Burst-Induced Hypoxia Is Associated With Macrophage Inflammatory Profiles as Revealed by Cellular Genome-Wide Association.

Background: In mammalian species, hypoxia is a prominent feature of inflammation. The role of hypoxia in regulating macrophage responses via alteration in metabolic pathways is well established. Recently, oxidative burst-induced hypoxia has been shown in murine macrophages after phagocytosis. Despite the available detailed information on the regulation of macrophage function at transcriptomic and epigenomic levels, the association of genetic polymorphism and macrophage function has been less explored. Previously, we have shown that host genetics controls approximately 80% of the variation in an oxidative burst as measured by nitric oxide (NO-). Further studies revealed two clusters of transcription factors (hypoxia-related and inflammatory-related) are under the genetic control that shapes macrophages' pro-inflammatory characteristics. Material and Methods: In the current study, the association between 43,066 autosomal Single Nucleic Polymorphism (SNPs) and the ability of MDMs in production of NO- in response to E. coli was evaluated in 58 Holstein cows. The positional candidate genes near significant SNPs were selected to perform functional analysis. In addition, the interaction between the positional candidate genes and differentially expressed genes from our previous study was investigated. Results: Sixty SNPs on 22 chromosomes of the bovine genome were found to be significantly associated with NO- production of macrophages. The functional genomic analysis showed a significant interaction between positional candidate genes and mitochondria-related differentially expressed genes from the previous study. Further examination showed 7 SNPs located in the vicinity of genes with roles in response to hypoxia, shaping approximately 73% of the observed individual variation in NO- production by MDM. Regarding the normoxic condition of macrophage culture in this study, it was hypothesized that oxidative burst is responsible for causing hypoxia at the cellular level. Conclusion: The results suggest that the genetic polymorphism via regulation of response to hypoxia is a candidate step that perhaps shapes macrophage functional characteristics in the pathway of phagocytosis leading to oxidative burst, hypoxia, cellular response to hypoxia and finally the pro-inflammatory responses. Since all cells in one individual carry the same alleles, the effect of genetic predisposition of sensitivity to hypoxia will likely be notable on the clinical outcome to a broad range of host-pathogen interactions.

Host Tolerance to Infection with the Bacteria that Cause Bovine Respiratory Disease.

Calves vary considerably in their pathologic and clinical responses to infection of the lung with bacteria. The reasons may include resistance to infection because of pre-existing immunity, development of effective immune responses, or infection with a minimally virulent bacterial strain. However, studies of natural disease and of experimental infections indicate that some calves develop only mild lung lesions and minimal clinical signs despite substantial numbers of pathogenic bacteria in the lung. This may represent "tolerance" to pulmonary infection because these calves are able to control their inflammatory responses or protect the lung from damage, without necessarily eliminating bacterial infection. Conversely, risk factors might predispose to bovine respiratory disease by triggering a loss of tolerance that results in a harmful inflammatory and tissue-damaging response to infection.

Effect of tracheal antimicrobial peptide on the development of Mannheimia haemolytica pneumonia in cattle.

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 ß-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.

The effect of host genetics on in vitro performance of bovine monocyte-derived macrophages.

The dynamic interaction between the host and pathogens, along with environmental factors, influences the regulation of mammalian immune responses. Therefore, comprehensive in vivo immune-phenotyping during an active response to a pathogen can be complex and prone to confounding effects. Evaluating critical fundamental aspects of the immune system at a cellular level is an alternative approach to reduce this complexity. Therefore, the objective of the current study was to examine an in vitro model for functional phenotyping of bovine monocyte-derived macrophages (MDM), cells which play a crucial role at all phases of inflammation, as well influence downstream immune responses. As indicators of MDM function, phagocytosis and nitric oxide (NO-) production were tested in MDM of 16 cows in response to 2 common bacterial pathogens of dairy cows, Escherichia coli and Staphylococcus aureus. Notable functional variations were observed among the individuals (coefficient of variation: 33% for phagocytosis and 70% in the production of NO-). The rank correlation analysis revealed a significant, positive, and strong correlation (rho = 0.92) between NO- production in response to E. coli and S. aureus, and a positive but moderate correlation (rho = 0.58) between phagocytosis of E. coli and S. aureus. To gain further insight into this trait, another 58 cows were evaluated solely for NO- response against E. coli. The pedigree of the tested animals was added to the statistical model and the heritability was estimated to be 0.776. Overall, the finding of this study showed a strong effect of host genetics on the in vitro activities of MDM and the possibility of ranking Holstein cows based on the in vitro functional variation of MDM.

Genetic characterisation of methicillin-resistant Staphylococcus aureus and Staphylococcus pseudintermedius in pets and veterinary personnel in Iran: new insights into emerging methicillin-resistant S. pseudintermedius (MRSP).

OBJECTIVES: Methicillin-resistant staphylococci, including methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP), pose a threat to animal and human health worldwide. Veterinary staff and pets may play a role in the spread of resistant clones. METHODS: A total of 125 samples from veterinary staff (n=50), dogs (n=49) and cats (n=26) were investigated. Obtained isolates were tested for the methicillin resistance gene mecA and were subjected to multiplex PCR to differentiate coagulase-positive species. Following SCCmec and spa typing, isolates were tested for the presence of various toxin and virulence genes and phenotypic resistance to common antimicrobials. RESULTS: Overall, 4 MRSA were isolated from two veterinarians and two dogs and 19 MRSP were found in eleven dogs (12 isolates) and five cats (7 isolates). The MRSA isolates possessed sea (2) and eta (3) virulence genes and the MRSP isolates possessed sea (6), expA (15), expB (1) and siet (19) genes. SCCmec type II and three spa types (t186, t1816 and t10897) were identified in the MRSA isolates. Most of the MRSP isolates belonged to SCCmec types II (2 isolates) and V (10 isolates); however, the remaining 7 isolates were untypeable and contained class C1 mec. The majority of isolates were multidrug-resistant (MDR). CONCLUSION: These findings show that pets and veterinarians could be potential sources of MDR-MRSA and MDR-MRSP in Iran. Taken together, these findings warrant future investigations on the epidemiology and public-health significance of MDR-MRSA and MDR-MRSP both in veterinarians and companion animals in Iran.

Detection and molecular characterization of feline hemoplasmas in wild felid species in Iran in the Middle East.

Three feline hemoplasma species exist in felids: Mycoplasma haemofelis, 'Candidatus Mycoplasma haemominutum', and 'Candidatus Mycoplasma turicensis'. The aims of the study were to determine the presence of, and molecularly characterize, any hemoplasmas in wild felids, including the endangered Persian leopard in Iran, the Middle East. Blood samples were collected from 19 wild felids, including three Persian leopards. Using species-specific hemoplasma PCRs and ELISA serological testing for feline leukaemia virus and feline immunodeficiency virus (FIV), two Persian leopards were found to be infected with 'Ca. M. haemominutum' and were seropositive for FIV. Partial 16S rRNA gene sequences were generated for these 'Ca. M. haemominutum' species and subsequent phylogenetic analysis revealed 97.70% to 99.45% sequence identity with those found in domestic cats from Iran and other countries. This study confirms the presence of 'Ca. M. haemominutum' and concurrent FIV antibody in wild felids in Iran. This represents the first report of hemoplasma in wild felids in the Middle East as well as the first report of infection in Persian leopards.

Molecular characterization and phylogenetic analysis of feline hemoplasmas in domestic cats in Iran.

Three known feline hemoplasmas are Mycoplsama haemofelis, 'CandidatusMycoplasma haemominutum' and 'CandidatusMycoplasma turicensis'. They are described as cause of feline infectious anemia in domestic and wild felids. Other blood parasites or blood-related pathogens like concurrent retroviral infections may deteriorate the clinical condition and severity of anemia. The aims of this study were molecular characterization and phylogenetic analysis of hemoplasmas in domestic cats in Iran for the first time. Blood samples were collected from 185 healthy and diseased domestic cats. Blood smears were prepared and hematological parameters were measured to determine possible anemia. Using 16S rRNA gene universal and species specific polymerase chain reactions with the following sequencing, 47 (25.40%) of cats were hemoplasma positive. Also, 17.02%, 72.50% and 40.40% of total positive samples were M.haemofelis, 'Ca. M. haemominutum' and 'Ca. M. turicensis' infected, respectively. 10 (21.20%) of hemoplasma positive cats had anemic blood profiles (HCT < 24.00%). All M. haemofelis infected cases were included. Partial 16S rRNA gene phylogenetic analysis revealed a high identity between the hemoplasma species found in this study and domestic cat sequences existing in GenBank. Phylogenetic analysis revealed 94.00% to 100% sequence identity between sequences of this study and existing sequences in Genbank. All hemoplasma isolates in this study were grouped within a single clade and additionally subdivided into two groups; haemofelis group including M.haemofelis and 'Ca. M. turicensis' and haemominutum group including 'Ca. M. haemominutum'.

Reliability and validity of the Persian lower extremity functional scale (LEFS) in a heterogeneous sample of outpatients with lower limb musculoskeletal disorders.

PURPOSE: The aim was to culturally translate and validate the Persian lower extremity functional scale (LEFS) in a heterogeneous sample of outpatients with lower extremity musculoskeletal disorders (n = 304). METHOD: This is a prospective methodological study. After a standard forward-backward translation, psychometric properties were assessed in terms of test-retest reliability, internal consistency, construct validity, dimensionality, and ceiling or floor effects. RESULTS: The acceptable level of intraclass correlation coefficient >0.70 and Cronbach's alpha coefficient >0.70 was obtained for the Persian LEFS. Correlations between Persian LEFS and Short-Form 36 Health Survey (SF-36) subscales of Physical Health component (rs range = 0.38-0.78) were higher than correlations between Persian LEFS and SF-36 subscales of Mental Health component (rs range = 0.15-0.39). A corrected item--total correlation of >0.40 (Spearman's rho) was obtained for all items of the Persian LEFS. Horn's parallel analysis detected a total of two factors. No ceiling or floor effects were detected for the Persian LEFS. CONCLUSIONS: The Persian version of the LEFS is a reliable and valid instrument that can be used to measure functional status in Persian-speaking patients with different musculoskeletal disorders of the lower extremity. Implications for Rehabilitation The Persian lower extremity functional scale (LEFS) is a reliable, internally consistent and valid instrument, with no ceiling or floor effects, to determine functional status of heterogeneous patients with musculoskeletal disorders of the lower extremity. The Persian version of the LEFS can be used in clinical and research settings to measure function in Iranian patients with different musculoskeletal disorders of the lower extremity.

Assessment of immunity against avian colibacillosis induced by an aroA mutant containing increased serum survival gene in broilers

Colibacillosis is an important disease in the poultry industry which causes serious economic damages. As it is suggested that vaccination is one of the means to control colibacillosis, we tried to investigate the vaccine potential of a ÃaroA derivative of an O78:K80 avian pathogenic Escherichia coli containing increased serum survival gene. 490 chicks were selected as follows: For assessment of virulence of ÃaroA mutant, 30 chicks were divided into three groups and injected with 0.5ml of PBS or bacterial suspension containing either10(7)colony forming units (CFU) of mutant or parent strains via subcutaneous route. Macroscopic lesions and mortality rate were recorded in different groups during the week after challenge. For assessment of safety and immunogenicity of the ÃaroA mutant, three groups of 20 chicks were vaccinated by aerosol administration of 250 ml of suspension containing 10(8) CFU of mutant strain at days 1 and 14, while the two other groups received PBS or wild type strain. Macroscopic lesions and mortality rate were recorded in different groups until day 21. To determine whether the vaccination is protective against challenges or not, the chickens were vaccinated at days 1 and 14 and challenged intramuscularly with either a homologous or heterologous strains at day 21. Macroscopic lesions and mortality rate were recorded in different groups during the week after challenge. The results revealed that the ÃaroA mutant was slightly virulent, however it was safe and did not cause mortality, lesions or weight loss after vaccination. Antibody responses were similar in the control and mutant groups and vaccination did not induce a significant humoral immunity. The mutant could not protect chickens against both homologous and heterologous challenges. This could be due to several factors such as the high amount of maternal antibodies in the first two weeks of life, and the vaccination procedure.

Assessment of immunity against avian colibacillosis induced by an aroA mutant containing increased serum survival gene in broilers.

Colibacillosis is an important disease in the poultry industry which causes serious economic damages. As it is suggested that vaccination is one of the means to control colibacillosis, we tried to investigate the vaccine potential of a ∆aroA derivative of an O78:K80 avian pathogenic Escherichia coli containing increased serum survival gene. 490 chicks were selected as follows: For assessment of virulence of ∆aroA mutant, 30 chicks were divided into three groups and injected with 0.5ml of PBS or bacterial suspension containing either10(7) colony forming units (CFU) of mutant or parent strains via subcutaneous route. Macroscopic lesions and mortality rate were recorded in different groups during the week after challenge. For assessment of safety and immunogenicity of the ∆aroA mutant, three groups of 20 chicks were vaccinated by aerosol administration of 250 ml of suspension containing 10(8) CFU of mutant strain at days 1 and 14, while the two other groups received PBS or wild type strain. Macroscopic lesions and mortality rate were recorded in different groups until day 21. To determine whether the vaccination is protective against challenges or not, the chickens were vaccinated at days 1 and 14 and challenged intramuscularly with either a homologous or heterologous strains at day 21. Macroscopic lesions and mortality rate were recorded in different groups during the week after challenge. The results revealed that the ∆aroA mutant was slightly virulent, however it was safe and did not cause mortality, lesions or weight loss after vaccination. Antibody responses were similar in the control and mutant groups and vaccination did not induce a significant humoral immunity. The mutant could not protect chickens against both homologous and heterologous challenges. This could be due to several factors such as the high amount of maternal antibodies in the first two weeks of life, and the vaccination procedure.