الفهرس 
Introduction
Poultry sector worldwideOnly 14 pages are availabe for public view
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Abstract
In this study, the prevalence of Salmonella Enteritidis, Salmonella Typhimurium and Pseudomonas aeuroginosa was estimated in 11 poultry farms located in Assiut Governorate. A total of 600 samples, including litter (105), feed (105), water (87) and swabs from cloacae (95), walls (104), and water troughs (104) were collected from these poultry farms.
After biochemical and PCR identification of the selected bacteria, each bacteria was allowed to grow in a 96 well microtitre plate to form a strong and mature bacterial collection which encapsulated by exoplysaccharides layers called biofilms. Each bacterial strain was targeted by the best known antimicrobial metal based nanoparticles (silver nanoparticles) and with one of most common used disinfectants (sodium hypochlorite).
The antibiofilms efficiency of the selected agents was evaluated and measured by microtitre plate reader.
The results obtained in this study revealed that:
1- Prevalence of Salmonella Enteritidis, Salmonella Typhimurium and Pseudomonas aeuroginosa in poultry farms.
The total number of the collected samples from 11 poultry farms was 600 samples, from which 129 (21.5%) were positive for Salmonella spp. which represent 34 (26.36 %), 20 (15.50 %), 16 (12.4 %), 23 (17.83 %) , 22 (17.05 %) and 14 (10.85 %) for litter samples, feed samples, water samples, water troughs swabs, cloacal swabs and wall swabs, respectively.
from the positive salmonella strains, 35 samples were selected and molecularly identified by Multiplex PCR. After molecular identification, the result indicated that, 19 starins was positive for Salmonella Typhimurium and 2 strains was positive for Salmonella Enteritidis, representing 54.29% and 5.71%, respectively.
Furthermore, the results showed high prevalence of Salmonella spp. in litter samples, followed by water troughs swabs, cloacal swabs, feed samples, water samples and finally wall swabs.
Regarding Pseudomonas aeuroginosa, the total number of the collected samples from all selected poultry farms was 600 samples, 81 (13.5%) samples were positive representing, 14 (17.28%), 12 (14.81%), 18 (22.22%), 26 (32.10%), 9 (11.11%) and 2 (2.47%) for litter samples, feed samples, water samples, water troughs swabs, cloacal swabs and wall swabs, respectively.
The results showed high prevalence of Pseudomonas aeruginosa in water troughs swabs, followed by water samples, litter samples, feed samples, cloacal swabs and finally wall swabs. After that 15 strains was selected and molecularly identified by conventional PCR, and 4 strains were found positive for Pseudomonas aeuroginosa, representing 26.67%.
2- Minimum Inhibitory Concentration and Minimum Bactericidal Concentration of silver nanoparticles and sodium hypochlorite on Salmonella Typhimurium, Salmonella Enteritidis and Pseudomonas aeuroginosa.
The results showed that the Minimum Inhibitory Concentration (MIC) of silver nanoparticles (AgNPs) on Salmonella Typhimurium, Salmonella Enteritidis and Pseudomonas aeuroginosa was 15µg/ml, while Minimum Bactericidal concentration (MBC) was 20µg/ml. While, the (MIC) of sodium hypochlorite (NaOCL) on Salmonella (Typhimurium and Enteritidis), and Pseudomonas aeuroginosa was 1600 and 2200 µg/ml respectively, while (MBC) was 2000 and 2600 µg/ml, respectively.
3. Prevention of bacterial biofilms formation
During the production of biofilm we used glucose as a supplement for biofilm production in case of Salmonella Typhimurium and Salmonella Enteritidis by 2% and in Pseudomonas aeuroginosa biofilm by 1%. Also we used 0% glucose as a trial for production of Salmonella Typhimurium biofilms.
3.1. Effect of silver nanoparticles (AgNPs) on prevention of biofilms formed by Salmonella Typhimurium
The results showed that the percentage of biofilms inhibition formed by Salmonella Typhimurium treated with 10 µg/ml, 15 µg/ml, 20 µg/ml and 25 µg/ml of AgNPs was (77.95%, 82.89%, 84.38% and 84.96%); and (55.99%, 66.59%, 68.85% and 69.34%) for bacterial culture supplied with and without glucose, respectively.
3.2. Effect of silver nanoparticles on prevention of biofilms formed by Salmonella Enteritidis
The results showed that the percentages of Salmonella Enteritidis biofilms inhibition treated with 10µg/ml, 15µg/ml, 20µg/ml, 25µg/ml of AgNPs was 71.38 %, 76.19%, 77.37% and 78.85%, respectively.
3.3. Effect of sodium hypochlorite (NaOCL) on prevention of biofilms formed by Salmonella Typhimurium
The percentages of biofilms inhibition treated with 1600 µg/ml, 1800 µg/ml, 2000 µg/ml, 2200 µg/ml NaOCL and control was (79.11%, 82.51%, 83.78% and 83.89%) and (71.62%, 73.16%, 73.77% and 76.11%) for bacterial culture supplied with and without glucose, respectively.
3.4. Effect of sodium hypochlorite (NaOCL) on prevention of biofilms formed by Salmonella Enteritidis
The percentages of Salmonella Enteritidis biofilms inhibition after treatment with 1600 µg/ml, 1800 µg/ml, 2000 µg/ml and 2200 µg/ml NaOCL was 71.49%, 74.16%, 75.05% and 75.76%, respectively.
3.5. Effect of AgNPs on prevention of biofilms formed by Pseudomonas aeuroginosa
The results showed that the percentage of biofilms inhibition treated with 10 µg/ml, 15 µg/ml, 20µg/ml, 25µg/ml of AgNPs was 94.36%, 96.72%, 97.53% and 97.86 %, respectively.
3.6. Effect of sodium hypochlorite (NaOCL) on prevention of biofilms formed by Pseudomonas aeuroginosa
The findings showed that the percentages of biofilms inhibition treated with 2200 µg/ml, 2400 µg/ml, 2600 µg/ml and 2800 µg/ml NaOCL was 93.17%, 96.12%, 96.52% and 96.57%, respectively.
The results revealed that silver nanoparticles (AgNPs) and sodium hypochlorite (NaOCl) were able to promote a significant reduction on the biofilm formation formed by all of the tested bacteria adhe¬red to polystyrene wells (P<0.05) and their efficiency was concentration dependent.
4. Controlling of bacterial biofilms
4.1. Effect of 25 µg/ml of silver nanoparticles (AgNPs) on controlling of biofilms formed by Salmonella Typhimurium
The results showed that the percentages of biofilms inhibition after contact times of 30min, 1hrs, 1.5hrs, 2hrs, 2.5hrs, 3hrs were 50.85%, 60.20%, 71 %, 81.41%, 84.60% and 87.43%, respectively in bacterial culture supplied with glucose. While, the percentage of biofilms inhibition after contact times of 30min, 1hrs, 1.5hrs, 2hrs without glucose supplements were 61.05, 67.26, 72.32 and 78.71%, respectively.
4.2. Effect of 25 µg/ml of silver nanoparticles (AgNPs) on controlling of biofilms formed by Salmonella Enteritidis
The results showed that the percentages of biofilms inhibition after contact times of 30min, 1hrs, 1.5hrs, 2hrs, 2.5hrs, 3hrs were 48.70%, 63.15%, 78.93%, 80.94%, 83.63% and 87.67 %, respectively.
4.3. Effect of 2200 µg/ml NaOCL on controlling of biofilms formed by Salmonella Typhimurium
The percentages of biofilms inhibition in bacterial culture supplied with glucose after contact times of 15min, 30 min, 45 min, 1hrs, 1.5hrs and 2hrs, were 69.70%, 71.13%, 75.14%, 79%, 84.69% and 87.42%, respectively. While, the percentage of biofilms inhibition in bacterial culture without glucose supplements after contact times of 15min, 30 min, 45 min, 1hrs, were 75.03%, 76.05%, 76.46%, 78.96%, respectively.
4.4. Effect of 2200 µg/ml NaOCL on controlling of biofilms formed by Salmonella Enteritidis
The results showed that the percentages of biofilms inhibition after contact times of 15min, 30 min, 45 min, 1hrs, 1.5hrs, and 2hrs were 73.83%, 78.31%, 78.95%, 84.69%, 87.71% and 89.37%, respectively.
4.5. Effect of 25 µg/ml of silver nanoparticles (AgNPs) on controlling of biofilms formed by Pseudomonas aeuroginosa
The result showed that the percentages of biofilms inhibition after contact times of 15min, 30 min, 45 min, 1hrs, 1.5hrs, 2hrs, and 2.5hrs, were 47.45%, 64.16%, 72.61%, 72.95%, 77.42%, 81.31% and 87.55%, respectively.
4.6. Effect of 2800 µg/ml NaOCL on controlling of biofilms formed by Pseudomonas aeuroginosa
The result showed that the percentages of biofilms inhibition after contact times of 5min, 15min, 30 min, 45 min, 1hrs, and 1.5hrs were 81.43%, 83.79%, 87.34%, 87.93%, 88.30% and 90.31%, respectively.
The results showed that AgNPs was effectively control the mature biofilms (stage 2) formed by Pseudomonas aeuroginosa and (stage 3) that formed by both Salmonella Typhimurium and Salmonella Enteritidis. Moreover, we observed that the antibiofilm efficiency of AgNPs increased with the increase of its contact times with the biofilms
The present study showed that mature biofilms formed by both Salmonella Typhimurium and Salmonella Enteritidis and young biofilms formed by Pseudomonas aeuroginosa were significantly reduced after treatment with NaOCL after nearly all used contact times. Moreover its efficacy was concentration and contact times dependent.
The current study emphasi¬zes that the correct and conscious of cleanliness, hygiene, sanitation, and health education of workers must be daily and continuous, in addition to equipment maintenance and periodic exchange and treatment of equipment. If these parameters are che¬cked consistently, the installation process of the biofilm is hindered and, thus, the persistence of pathogenic bacteria with the constant contamination of the poultry and their environment will be reduced and may even be eradicated.