Background: Brucellosis is a zoonotic disease of worldwide importance among animal and humans. The most important virulence factor of Brucella melitensis is related to intra-macrophage survival. On the other hand, the side effects of the current brucellosis treatment regime, it is necessary to find out new antimicrobial agents to treat the disease.Objective: To Isolate Brucella melitensis from local white cheese and raw milk by culture method with identification using PCR and determination of their susceptibility to classical antibiotics and silver and zinc oxide nanoparticles.Materials and methods: A total of 150 local soft cheese and raw milk samples collected from different local markets in Erbil city and were examined for the presence of Brucella melitensis during a period of (6) months (November 2015 to April 2016).Selective media; such as, Brucella agar were used for the isolation, and identified according to standard biochemical tests and confirmed by PCR.Antibiotic susceptibility test determined by Kirby-Bauer disk diffusion method and the antimicrobial activity of silver and zinc oxide nanoparticles were carried out in Muller–Hinton agar with 1% sheep’s blood by well diffusion method. Five mm diameter wells were prepared and loaded with Ag(20 nm size) and ZnO (20 nm size) nanoparticles dilutions, finally the combination of ampicillin/ cloxacillin with the nanoparticles were tested against isolates of Brucella melitensis.Results: Out of the 150 food samples, 53(35.33%) were contaminated; 21(28%) of the total samples of local soft cheese and 32(42.6%) of raw milk was contaminated with Brucella melitensis. Twenty isolates were identified according to standard biochemical tests, and confirmed by PCR for detection of pure Brucella genomic DNA in PCR. Brucella-specific primer BgF/BgR, were evaluated for detection of pure Brucella genomic DNA, provided bands on agarose gel corresponding to a 208 base pair product when compared to molecular ladder, the specific primer IS711were detected for Brucella melitensis, and achieved by given bands on agarose electrophoresis corresponding to 731 base pair from the total isolates. Seventeen from 20 isolates were found positive for Brucella with BgR/BgF primers and 15 isolates were positive for IS711 primer. The sensitivity to antibioticsshowed that the resistance to ampicillin and ceftazidime were (85%), for aampicillin/cloxacillin was (45%), and for imipenem and piperacillin were 80% and 90% respectively. The inhibition zone of ZnO-NP against Brucella melitenisis ranged between 10-20 mm when the concentration was 10-1000 ppm. While the inhibition zone of Ag NP was 11.5-24.5 mm. Combination of amoxicillin/ cloxacillin with nanoparticles show a synergistic effect as demonstrated by the increase of inhibition zone to 20 mm fir ZnO-NP and 23 mm for AgNP nanoparticles.Conclusion: Brucella melitensis contaminate local white soft cheese and raw milk and showed variable sensitivity to antibiotics and some isolates were resistant to ampicillin/ cloxacillin, ceftazidime, imipenem, piperacillin, and trimethoprim-sulphamethoxazole. The present study data show that silver and zinc oxide nanoparticles inhibit the growth of Brucella melitensis. The combination of silver nanoparticles and ampicillin/ cloxacillin showed a synergistic effect.

The present study aimed to determine the antibacterial activity of lactic acid bacteria metabolites against Listeria monocytogenes which was isolated from some foods in local markets of Erbil and Koya cities; 225 food samples were examined for the presence of Listeria species particularly L. monocytogenes from October 2010 to March 2011. The studied samples included 70 samples of raw chicken meat, 55 samples of raw milk, 50 samples of cheese and 50 samples of raw red meat. According to motility test, hemolysin production, sugar fermentation test, 8 isolates of L. monocytogenes were identified, 1 (2 %) isolate from cheese, 2 (4 %) isolates from red meat and 5 (7.3 %) isolates from chicken meat. The percentages of contaminated foods for Listeria species from chicken meat, raw milk, cheese and red meat were 20, 9, 20 and 22% respectively. With respect to the biocontrolling attempt, the effect of cell free extract (CFE) of lactic acid bacteria (LBA) which is considered as safe against isolated L. monocytogene was used as biocontrolling agent. The CFE of lactic acid bacteria which isolated from local dairy products, was tested for its controlling ability by agar diffusion method, the CFE showed inhibition zone from (15-23 mm) in diameter. Also the minimum inhibitory concentration MIC of CFE was determined at three additive percentages (0.5, 1.0 and 1.5ml to 10 ml of nutrient broth), the inhibition percentage ranged from (28.75-48.97) at (0.5 %), (52.13-95.55) at (1 %) and (82.93-98.15) at (1.5 %) additive percentage of CFE of LAB.

The present study was aimed to isolate and characterize Escherichia coli pathogenic types from raw red meat, poultry and ready to eat food sources. Enrichment, selective plating, biochemical tests as well as vietik kit system have been applied for isolation and identification of pathogenic E. coli from collected samples. Out of 200 food samples, 180 (90%) were contaminated with E. coli, the highest contaminated foods were red meat 74 (92.5%), while the poultry 55 (92%), and 51 (85%) of ready to eat foods. The prevalence of E. coli O157:H7 found in red meat is 20% and 18% in poultry while 14% of the ready to eat food samples were contaminated with this bacterium. The isolates were screened for some virulence genes using PCR assays; from the total (128) isolates, 98 (76.5%) possessed uidA gene as detected in 40 (74%) red meat, 30(81%) and 28(75.5%) in poultry and ready to eat food respectively, while 37 (28.9%) of the isolates possessed lt gene as follows; 10(18.5), 15 (40.5) and 12(32.4) in red meat, poultry and ready to eat food, respectively. The results showed the detection flicH7 gene specific for E. coli O157:H7 were 7 (38.8%), 5 (35.7%) and 4(26.6%) of the total 47 isolates were possessed the flicH7 gene found in red meat, poultry and ready to eat food respectively. Our results showed that E. coli isolates presence in high percentage in raw red meat, poultry and ready to eat foods (kebab, shawerma and hamburger) and virulence genes; udiA, lt and flicH7 genes detected by PCR in the isolates and may be a source of potentially pathogenic E. coli for humans.

Article InfoEscherichia coli serotype O157:H7 is a recently recognized human pathogen associated with hemorrhagic colitis, the efficacy of MacConkey agar containing sorbitol (SMAC medium) instead of lactose as a differential medium for the detection of E. coli O157:H7 in foods cultures was determined in comparison with MacConkey agar. The study involving 200 different food samples, the growth of E. coli O157:H7 on SMAC medium was appeared and purified in pure culture as colorless colonies in contrast to other E. coli, from the total(200) different ready to eat food samples; 96(66.7%) were contaminated with bacteria E. coli O157:H7 and 48 (33.3%) for other E. coli. Bacteriological investigation were done on (200) samples of (meat steak, grilled chicken, shawerma meat and chicken), the result indicated that 144 (72. %) of samples was contaminated with E. coli divided as 96 (66.7%) and 48 (33.3%) for E. coli O157:H7 and other E. coli respectively. The percentage of contamination with E. coli O157:H7 isolated from meat steak, meat shawerma, chicken shawerma, grilled chicken samples were 16(16.6%), 27(28.1%), 32(33.33%), 21(21.8%)) respectively. The susceptibility of E. coli to different antimicrobial drugs was carried out using antibiotic discs, the percentage of sensitivity were (100, 93.7, 89.5, 58.3, 50)%. Against danofloxacin, imipenem, fosfomycin, ciprofloxacin, azithromycin, respectively, and 41.6% for each; trimethoprim, gentamicin and doxycyclin. On the other hand the resistance to ampicillin, amikacin, amoxicillin, cefixime and tertracycline were (97.9, 95.8, 89.5, 68.7, 56.2)% while the isolated bacteria appeared the resistance percentage (83.3%) to chloramphenicol and erythromycin, while it was varied in resistant to cephalothin, nalidixic acid and cefazoline. All the isolates of E. coli O157: H7 96(100%) were resistance to ampicillin, amikacin, chloramphenicol and erythromycin, as well as were resistance to tetracycline, amoxicillin, cefixim and trimethoprim, while all the isolates 96(100%) were sensitive to danofloxacin. The percentage of resistance to gentamycin and nalidixic acid were 38(39.5), and the resistant to azithromycin, cefazoline, doxycycline and cephalothine were varied as 80(83.3), 46(47.9), 44(45.8) and 40(41.6), respectively. In present study Cell free extract (CFE) metabolites of lactic acid bacteria (LAB) include (2) strains of Lactobacillus bulgaricus (LB), and Streptococcus thermophilus (ST) grown in MRS and M17 media have inhibitory effect against E. coli O157:H7and E. coli, by using well diffusion method. The minimum inhibitory concentration of CFE of Lactobacillus bulgaricus and Streptococcus thermophilus at 50, 75 and 100 µl v/v which concentrated for two folds, appeared that the inhibition zones increase as the concentration of CFE increase, and ranged from (10-16) mm against bacteria E. coli, while the effect of Streptococcus thermophilus varied between (6-10) mm against same bacteria. On the other hand the effect of Lb. bulgaricus and St. thermophiles on the growth of E. coli O...

In this present research, acetic acid bacteria were isolated from local vinegar samples produced from fermented apple, date and grape; from all (26) vinegar samples; twenty-one isolates of the bacteria were obtained as a dense and smooth colonies with creamy colour on the surface of HS-agar medium, four isolates were identified as Acetobacter xylinum by followed many physiological and biochemical tests, the isolates were gram negative, oxidase negative and catalase positive, the isolates showed positive growth at (25, 30 and 40)°C and furthermore at pH 7.0 and 4.5, but there was no growth at (45°C), pH (2.5 and 8.5). All isolated bacteria were unable to liquefy gelatin. Four isolates were capable to ferment glucose, xylose, galactose, mannose and unable to ferment lactose, mannitol and maltose.The isolates BS2, BS3, BS8 and BS20 had ability for bacterial cellulose production. The percentage of dry weight of cellulose ranged between (2.163 – 7.234)%. Since BS2 showed the best productivity, which had the maximum cellulose production (7.234g/L) was obtained after incubation time of 7 days with Hestrin and Hchramm (HS) media in static fermentation. The isolates (BS2, BS3, BS8 and BS20) were examined for bacterial cellulose production in HS broth medium. The dry weight of crude cellulose produced by each isolates was measured and ranged from (0.36-0.42) gm. and the pH value of bacterial cellulose were (6.2-6.9), approximately equal and nearly to the neutral values with comparison with plant cellulose. The thickness of bacterial cellulose membrane is a key parameter in preparing film, the initial thickness of the wet BC membrane was measured as 32 micrometers and after drying the computed thickness of BC membrane decreased to 0.4 µm. The average tensile strength value and the average elongation at break value of the dried BC films were 34.5 MPa and 5.2% respectively.