Pasteurella (P.) multocida and Mannheimia (M.) haemolytica are the most two common pathogenic bacterial agents causing pneumonia in calves. Both bacteria are associated with significant economic losses in the cattle industry due to high morbidity and mortality rates, especially in the case of severe infections. The objectives of the present study were to perform serotyping and genotyping, as well as characterization of the virulence-associated genes in 48 bacterial isolates; 33 P. multocida and 15 M. haemolytica. All strains were isolated from pneumonic cattle calves showing respiratory manifestations such as fever, nasal discharges, and rapid breathing in North Upper Egypt governorates (Beni-Suef and El-Fayoum). PCR was applied as a confirmatory test using a specific universal gene, kmt1, and rpt2 for P. multocida and M. haemolytica, respectively. The results show that 29 (87.9%) P. multocida and 15 (100%) M. haemolytica isolates were positive for the corresponding universal gene. The results of serotyping indicate that 86.2% of P. multocida isolates belonged to serotype B:2, while 13.8% were untyped. Meanwhile, 60% and 40% of M. haemolytica isolates belonged to serotype 2 and serotype 1, respectively. Investigation of virulence-associated genes showed that all the tested P. multocida isolates harbored nanB, omp87, and toxA genes. Four M. haemolytica isolates harbored both gcp and lktC genes and of these, three isolates harbored the ssa gene. Sequencing of toxA gene of P. multocida and lktC gene of M. haemolytica in the current strains indicated a great homology with strains uploaded in gene banks from different hosts and localities worldwide.

B ovine respiratory disease (BRD) is considered one of the most common worldwide affections in calves causing huge economic losses due to reduction of feed efficiency, average daily gain, overall performance and finally calf mortality (Härtel et al., 2004; Taylor et al., 2010). The incidence of BRD has been reported with variability from 5 to 66% in feedlot cattle and it is the most costly beef cattle disease (Snowder et al., 2006). BRD in calves is a multi-etiological entity associated with several infectious agents and other factors (Fulton, 2009). Besides infectious agents, multiple environmental and research Article

Background and Aim:Mastitis is an important threat facing goat milk industry and is the most common cause of culling. Efficient control of mastitis, based on efficient diagnosis of diseased animals, would improve milk production and reproductive efficiency. In subclinical mastitis (SCM), infected goats demonstrate neither udder symptoms nor abnormal milk. Corynebacterium pseudotuberculosis is an infectious causative agent of mastitis, mostly results as an extension of infection from the supramammary lymph node, and causes financial losses in the goat industry. This study aimed to estimate the prevalence of SCM with emphasis on C. pseudotuberculosis mastitis in Egyptian dairy goats in the selected farms.Materials and Methods:A total of 336 half milk samples were collected from 177 dairy goats of various crossbreeds, in mid-to-late lactation period, after clinical examination. All samples were examined bacteriologically, while somatic cell count (SCC) was determined only in 180 half milk samples of the clinically healthy milk samples. The isolated and identified C. pseudotuberculosis was examined for evidence of virulence genes (Phospholipase D [pld] and β-subunit of RNA polymerase [rpoB]) by polymerase chain reaction (PCR).Results:The prevalence of clinical mastitis was 30.5%, while 69.5% of animals were apparently healthy and secreted milk was normal. Of those 180 clinically healthy half milk samples, 96 milk samples (53.33%) showed SCM as detected by SCC (SCC ≥1,000,000 cells/ml). Coagulase-negative staphylococci were the most prevalent bacteria (41.96%), then Staphylococcus aureus (37.5%) and C. pseudotuberculosis (7.14%). Molecular diagnosis of virulence genes revealed evidence of pld gene in 16 isolates (66.66%), and rpoB gene in 6 samples (25%) of the 24 bacteriologically isolated C. pseudotuberculosis. Here, we describe, for the 1st time, isolation and identification of C. pseudotuberculosis from milk of does suffering from SCM in Egypt.Conclusion:C. pseudotuberculosis must be considered for routine bacteriological examination of milk from dairy goats, particularly herds with a history of caseous lymphadenitis. Pld gene-based PCR is more reliable than rpoB gene-based ones for the diagnosis of C. pseudotuberculosis.

A B S T R A C TA total of 213 milk samples from clinically mastitic cattle cows were collected from different Governorates of Egypt and transferred in ice box as soon as possible to Bacteriological lab. in Animal Reproduction Research Institute (ARRI) in Giza Governorate (AL-Haram) for bacteriological examination of most important pathogens causing clinical mastitis with special references for isolation and strict identification of Salmonella species. All samples were collected during the period from December 2016 till July 2017 from governorates of Egypt. The bacteriological investigations revealed that 8 (3.7%) of Salmonella isolates were identified biochemically from all examined samples. Serological study showed that a total of 5 (2.3%) of Salmonella isolates were typed as Salmonella Typhimurium. Two strains of Salmonella Typhimurium were isolated singly in the rate of (0.93%) from all examined samples, also another two strains of Salmonella Typhimurium were isolated mixed with Staph aureus in the rate of (0.93%), meanwhile only one strain of same species was isolated mixed with E.coli in the rate of (0.47%). Cefiquinom and Enrofloxacin were sensitively in the rate of (100%), Ampicillin, Chloraphincol, Cloxacillin were resistance in the rate of (100 %) to Streptomycin and Amoxicillin. The molecular examination confirmed that all 5 examined serotyped strains were Salmonella Typhimurium. Virulence genes invA, hilA, avrA, were detected in examined sample by 100%, meanwhile sopE, ssaQ, and fimH genes were not detected by zero%. The objectives of the present study was to investigate the occurrence of Salmonella serotypes as well as to determine the frequency distribution of Six virulence genes (invA, hilA, avrA, ssaQ, sopE and fimH) in salmonella isolates from cattle clinical mastitic milk, in addition to determine the drugs of choice for treatment of most Salmonella strains causing cattle clinical mastitis.

The aim of the study was using polymerase chain reaction (PCR) technique for detecting the most bacteria causing mastitis in cows as streptococci spp., Escherichia coli and Staphylococcus aureus by using Genus specific primers for each one. One hundred milk samples were collected from cases of subclinical bovine mastitis positive for California Mastitis Test (CMT). The samples were bacteriologically cultivated on to 5% sheep blood agar and also, on different types of media (MacConkey's agar plates, Edward's agar medium and mannitol salt agar) to isolate the major bacteria causing mastitis and identified biochemically. Finally, these bacteria were identified by using PCR technique with a specific primer for each genus. The PCR results revealed that E. coli 16/46 (34.7%), Staphylococcus aureus (S. aureus) 12/40 (30%) and streptococci spp. 11/39 (28.2%). Multiplex PCR for typing of streptococci spp. revealed that St. agalactiae 3/39 (7.69%) and St. dysgalactiae 8/39 (20.51%). In conclusion, in the present study, PCR analysis was used for diagnosis of major bacteria causing subclinical mastitis in cows by using specific primers for each one. The most prevalent bacteria causing subclinical mastitis were E. coli, S. aureus, S. dysgalactia and S. agalactia.