Aim:The aim of this study was to determine the relationship between phenotypic resistance and genotypic resistance of isolated serotyped pathogenic Escherichia coli isolates from the clinically diseased broiler.Materials and Methods:A total of 160 samples (heart, liver, kidney, and lung) were collected from 18 to 34 days old clinically diseased broiler from 40 broiler farms (3-5 birds/farm) reared in Giza and Kaluobaia Governorates for the isolation of pathogenic E. coli. Various E. coli isolates were tested for the pathogenicity based on Congo red (CR) dye binding assay. The obtained CR-positive E. coli isolates were subjected to serological identification using slide agglutination test. Disc diffusion test was used to study the sensitivity pattern of E. coli isolates to available 12 antibiotics. Polymerase chain reaction was performed for the detection of antimicrobial resistance genes in the studied pathogenic E. coli isolates.Results:The results revealed that 56 samples (35 %) were positive for E. coli. The results of the CR assay indicates that 20 isolates of 56 (35.7%) were positive and 36 isolates (64.3%) were negative. Identified E. coli serotypes of CR-positive isolates were 1 (O24), 2 (O44), 2 (O55), 5 (O78), 2 (O86), 1 (124), 3 (O127), 1 (O158), and 3 untyped. Resistance rate in disc diffusion test was 85% to oxytetracycline and kanamycin; 80% to ampicillin (AMP), clindamycin, and streptomycin (S); 75% to enrofloxacin; 65% to chloramphenicol; 55% to cefotaxime and gentamicin (CN); 45% to trimethoprim+sulfamethoxazole; 35% to erythromycin (ERI); and 30% to oxacillin. All strains are multidrug-resistant (MDR). Antibacterial resistance genes CITM, ere, aac (3)-(IV), tet(A), tet(B), dfr(A1), and aad(A1) were detected in 14 (70%), 12 (60%), 12 (60%), 8 (40%), 11 (55%), 8 (40%), and 9 (45%) of tested 20 isolates, respectively. Multidrug resistance was detected in the form of resistance to 42%-83.3% of tested 12 antibiotics. Three isolates (15%) of 20 tested isolates showed a relationship between phenotype and genotype and 17 (85%) showed irregular relation. Strains are sensitive and show resistant gene (P-G+) presented in three isolates for AMP (beta-lactam), one for ERI (Macrolide), as well as five isolates for trimethoprim (pyrimidine inhibitor). E. coli isolates had resistance and lacked gene (P+ G-) reported meanly in one isolate for CN (aminoglycoside), two isolates for tetracycline, four isolates for ERI, seven isolates for trimethoprim, and eight isolates for S (aminoglycoside).Conclusion:The study demonstrates that E. coli is still a major pathogen responsible for disease conditions in broiler. E. coli isolates are pathogenic and MDR. Responsible gene was detected for six antibiotics in most of the isolates, but some do not show gene expression, this may be due to few numbers of resistance genes tested or other resistance factors not included in this study.

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The pharmacokinetics of danofloxacin was determined in five clinically normal adult female goats after intravenous (IV) or intramuscular (IM) doses of 1.25 mg/kg body weight. Blood and urine samples were collected from each animal at precise time intervals. Serum and urine concentrations were determined using microbiological assay methods and the data were subjected to kinetic analysis. After intravenous injection, the serum concentration time curves of danofloxacin were characteristic of a two-compartment open model. The drug was rapidly distributed and eliminated with half-lives of 17.71 +/- 1.38 min and 81.18 +/- 3.70 min, respectively. The drug persisted in the central, highly perfused organs with a K12/K21 ratio of 0.67 +/- 0.25. The mean volume of distribution at a steady state (Vdss was 1.42 +/- 0.15 L/kg. After intramuscular administration, the serum concentration peaked after 0.58 +/- 0.04 h at approximately 0.33 +/- 0.01 microg/ml. While danofloxacin could be detected in serum for 4 and 6 h, it was recovered in urine for up to 24 and 72 h after IV and IM administration, respectively. The systemic bioavailability after IM injection was 65.70% +/- 10.28% and the serum protein-bound fraction was 13.55 +/- 1.78%.

Aim: Arthritis is one of the most economic problems facing poultry industry worldwide. The study was done to detect possible causes of arthritis in breeder chicken flock with emphasis on molecular identification of Mycoplasma synoviae (MS). Materials and Methods: This study was carried on chicken from broiler breeder flock of 57 weeks' age in Dakahlia, Egypt, suffered from arthritis with frequently 5-7% decrease in egg production, reduced fertility, and hatchability. Forty blood samples were randomly collected from individual birds in sterile tubes and used for serum separation. Serum samples were tested using serum plate agglutination (SPA) test against colored antigens for Mycoplasma gallisepticum (MG), MS, and Salmonella gallinarum-pullorum (SGP). On the other hand, 24 joint samples were collected. Of those 24 samples, 12 joint samples were subjected to bacteriological examination, while the other 12 were utilized for molecular diagnosis by polymerase chain reaction (PCR) for MS and avian reovirus (ARV). Results: SPA test results revealed the presence of antibodies against MG, MS, and SGP in tested sera in rates of 14/40 (35%), 35/40 (87.5%), and 9/40 (22.5%), respectively. Furthermore, 19 bacterial isolates were recognized from joint samples and identified as five Staphylococcus spp., nine Escherichia coli, three SGP, one Citrobacter, and one Proteus. The identified Staphylococcal isolates were three coagulase-positive staphylococci (two Staphylococcus aureus and one Staphylococcus hyicus) and two coagulase-negative staphylococci (one Staphylococcus epidermidis and one Staphylococcus lentus), while E. coli isolate serotypes were 1 O11, 2 O55, 3 O78, 1 O124, 1 O125, and 1 untyped. PCR proved that 12/12 (100%) samples were positive for MS variable lipoprotein hemagglutinin A (vlhA) gene, while ARV was not diagnosed in any of the examined samples. Four amplified vlhA gene of MS isolates (named MS-2018D1, MS-2018D2, MS-2018D3, and MS-2018D4) was successfully sequenced. Analysis of phylogenetic tree revealed the presence of 100% identity between each two sequenced isolates (isolates MS-2018D1 and MS-2018D4 and also isolates 2018D2 and MS-2018D3). However, the nucleotide similarity between four isolates was 88.6%. On the other hand, our field isolates MS-2018D1, MS-2018D4, MS-2018D2, and MS-2018D3 showed nucleotide identity with vaccine strain MS-H 98.4%, 98.4%, 88.1%, and 88.1%, respectively. Furthermore, the nucleotide similarities with field strains from Argentina ranged between 87.8% and 98.6%. Conclusion: Four field isolates of MS were identified in examined broiler breeder flock. A phylogenetic study of these isolates revealed the variation between isolated MS strains and vaccine strain. Therefore, further studies are required for evaluating the vaccine efficacy against the present field isolates of MS. In addition, application of MS immunization of breeder flocks is necessary for proper control of the disease.

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| Nano-sized drug delivery systems used to improve drug pharmacokinetics especially bioavailability. Different tetracycline loaded nanoemulsions were formulated and evaluated for thermodynamic stability, morphology, droplet size and zeta potential measurements. Pharmacokinetic of TC-NE (10% Mig, 50% S/CoS and 40% water with drug concentration of 5%, w/w) was investigated in rabbits following a single oral and IV doses (50 mg/kg bwt) and compared to tetracycline HCl powder (TC-Powder) at the same dose. Tetracycline concentrations were determined in plasma samples using standard high performance liquid chromatography (HPLC) procedure. Following IV injection higher AUC0-inf (83.3 ± 4.2 and 74.8 ± 2.9 μg/ml.h) and volume of distribution (Vdss) (0.78 ± 0.06 L/kg and 0.71 ± 0.10 L/ kg) reported for TC-NE compared to TC-Powder, respectively. Furthermore, after oral administration, TC-NE was slowly absorbed and eliminated than TC-Powder with longer t 1/2ka (0.518 ± 0.091 h and 0.253 ± 0.024 h) and t 1/2β (4.22 ± 1.67 h and 3.33 ± 0.68 h), respectively. Moreover, the time at which maximum tetracycline plasma concentration achieved (T max) was 0.869 ± 0.059 h for TC-NE and 0.397 ± 0.033 h for TC-Powder. Significantly higher area under curve AUC 0-t 20.4 ± 1.5 μg/ml.h and 11.1 ± 0.6 μg/ml.h and consequently higher bioavailability 29.2 ± 2.3% and 13.9 ± 0.8% was recorded for TC-NE than TC-Powder, respectively. Following oral admistiration TC-NE formula exhibited prolonged T> MIC of 10.36 ± 0.64 h compared to 7.1±0.32 h in TC-powder. In conclusion, the prepared Tetracycline loaded nanoemulsion formulation has improved oral bioavailability and prolonged the blood concentration time than TC-Powder. Further clinical studies are required to justify dosage that supports clinical efficiency.