الفهرس 
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Abstract
The results of clinical examination of the udders of lactating ewes (n=90; 180 udder halves) and does (n=32; 64 udder halves) revealed that out of 244 examined udder haves, 158 halves were apparently normal;115 in ewes and 43 in she-goats, while 86 halves showed complete loss of function;58 in ewes and 28 in she-goats.
A total number of 125 bacterial isolates were recovered from 122 milk samples from sheep and goats including 73 (58.4 %) Gram negative and 52 (41.6 %) Gram positive bacterial isolates.
Gram negative bacterial isolates (n=73) were identified as 68 E. coli (54.4 %), 3P. multocida (2.4%) and 2M. haemolytica (1.6%). On the other hand, Gram positive bacterial isolates (n=52) as 20 Streptococci (16% including S. agalactiae 13 (10.4%), S. dysgalactiae 4 (3.2%) and S. uberis 3 (2.4%) and 32 S. aureus (25.6 %).
Regarding animals, results of endometritis followed by collection of uterine swabs from sheep and goats showed that out of 84 apparently healthy examined animals, a total of 80 animals (68.97%) were positive (subclinical endometritis), while 4 animals (3.44%) were negative isolates from the samples of endometritis (116 samples).
A total number of 113 bacterial isolates were recovered from 116 examined sheep and goats and identified as follow; 89 (78.76 %) Gram negative and 24 (21.23 %) Gram positive bacterial isolates.
Gram negative bacterial isolates (n=89) were identified as 69 E. coli (61.06 %), 4 P. multocida (3.5%), 13 P. aeuginosa (11.5%) and 3M. haemolytica (2.65%). On the other hand, Gram positive bacterial isolates (n=24) as 6 E. faecalis (5.3 %), 5 E. faecium (4.44%), 4 Streptococci (3.53 %) and 9 S. aureus (7.96%).
The results of haemolytic activity of bacterial isolates (selected representatively) from mastitis milk samples on sheep blood agar revealed that 70.5% of the bacterial isolates were haemolytic; 47.6% were β-haemolytic while 22.9 % were α-haemolytic. Haemolysis was represented as 100%, 90%, 85.71% and 56% in M. haemolytica, Streptococcus spp., Staphylococcus spp. and E. coli, respectively. They were mostly β-haemolytic 29 isolates (47.6%) while, 18 isolates (29.5%) were γ-haemolysis.
The results of haemolytic activity of bacterial isolates from endometritis samples (selected representatively) on sheep blood agar of different bacterial pathogens revealed that 56.8% of the bacterial isolates were haemolytic; 20.3% were α-haemolytic and 36.5% were β-haemolytic. Haemolysis was represented as 100%, 87.5%, 85%, 61.1% and 40% in M. haemolytica, Streptococcus spp., Staphylococus spp., E. coli and P. aeruginosa, respectively. In addition, 27 isolates were β -haemolytic with a percentage of 36.5%. Whereas, 32 (43.2%) of the isolates were γ-haemolysis.
Biofilm production was represented as 39 E. coli isolates (65%) (18 isolates from mastitis 30% and 21isolates from endometritis 35%), 20 Staphylococci isolates (66.67%) (16 isolates from mastitis 53.33% and 4 isolates from endometritis 13.34%), 7 Streptococci isolates (70%) (5 isolates from mastitis 40%) and 3solates from endometritis (30%), 3P. aeruginosa isolates (42.85%), 3 P. multocida (50%) (1 isolates from mastitis 16.67% and 2 isolates from endometritis 33.33%) and two isolates from endometritis 66.67% and 2 Enterococci isolates (one isolate of E. fecalis from goat and one isolate from E. faecium from sheep) (40%) from uterine samples.
The results of in-vitro antimicrobial susceptibility of mastitis milk samples against 17 antimicrobial agents showed high susceptibility against ofloxacin (76%), followed by co-trimethoprim (73.6%), sulfamethoxazole-trimethoprim (71.2%), ciprofloxacin (70.4%), fosfomycin (68.8%), chloramphenicol (67.2 %) and doxycycline (65.6%). On the contrary, most of the isolates were resistant to amoxicillin-clavulanic acid (75.2 %), cefotaxime (72.8 %), amoxicillin (69.6 %), cephalexine (68.8 %), and cefotriaxone (64.8%).
All bacterial isolates recovered from uterine samples were tested for in-vitro antimicrobial susceptibility against 17 antimicrobial agents of 9 different antimicrobial classes. The results showed high susceptibility against co-trimethoprim (76.11%) followed by ofloxacin (73.45%), fosfomycin (72.57%), doxycycline (71.68 %), ciprofloxacin (69.91%), sulfamethoxazole-trimethoprim (69.03%), tetracycline (69.02%) and chloramphenicol (67.26%). On the contrary, most of the isolates were resistant to amoxicillin-clavulanic acid (76.11%), cefotaxime (71.68 %), amoxicillin (70.79 %), cephalexine (69.02 %) and cefotriaxone (58.41 %).
Using PCR to assess biofilm associated genes and MDR genes in different bacterial isolates as E. coli isolates harbored blaTEM genes (100%), while, qnrA gene was detected in 50% of the tested isolates of ovine endometritis. Meanwhile, all tested isolates harbored fimH virulence genes (100%). The iutA was detected in 25% of the tested isolates of endometritis of sheep only. P. aeruginosa harbored blaTEM, tetA, toxA and las1 with a prevalence rate of 100%. S. aureus isolates harbored mecA and coa (100%). The tetK and icaA genes were detected in 75% of the tested isolates. Streptococci isolates harbored aac(6’)aph(2’’) gene (100%). The tetO, cylE and cfb were detected in 75% of the tested isolates. P. multocida isolates isolates harbored nanB, toxA and omp87 with a prevalence rate of 100%. M. haemolytica isolates harbored gcp, itkC and ssa with a prevalence rate of 75%.
The results concluded that there is a strong correlation between the phenotypes and genotypes of AMR in different bacteria. Moreover, biofilm is a main problem for dairy farms affecting the udder health, uterine tissue and is considered as a risk for milk quality, fertility and consumer health. Also, biofilm formation, in turn, is associated with acquiring MDR by a high prevalence of bacterial pathogens recovered in this study.