BACKGROUND: Today, the fight against the bacteria causing foodborne diseases is of particular importance in the packaging of seafood. It is therefore vital to find new compounds with antibacterial properties.OBJECTIVES: In the present study, antibacterial properties of synthetic nanocomposite zinc chromite-zinc aluminate (ZnCr2O4-ZnAl2O4) on E. coli and Pseudomonas aeruginosa were studied.METHODS: After synthesis of nanocomposite, antibacterial activity of nanocomposite zinc chromite-zinc aluminate was evaluated via disk diffusion method, Minimum Inhibition Concentration (MIC), and Minimum Bactericidal Concentration (MBC) using the microdilution method.RESULTS: The results of this study revealed a higher sensitivity reaction of Pseudomonas aeruginosa (18.6±1.2 mm) compared to E. coli (12.7 ± 1.4 mm). No significant differences were observed between Gentamicin antibiotic and synthetic nanocomposite against Pseudomonas aeruginosa (P<0.05). The minimum MIC and MBC concentrations were seen in Pseudomonas aeruginosa (1.66 mg/ml) and the maximum concentration of MIC belonged to E. coli (5 mg/ml).CONCLUSIONS: In this study, the effects of nanoparticles on these gram-negative bacteria could be attributed to the small diameter of the ions, and hence the greater penetrability of these nanoparticles despite the wall's resistance. Based on the results, zinc chromite-zinc aluminate nanocomposite showed a better performance compared with gram-negative bacteria, specifically Pseudomonas aeruginosa resistant bacteria, and could be used for further studies in fisheries product packaging.

BACKGROUND: Diarrhea syndrome is associated with irrecoverable damages in the husbandry industry worldwide due to losses resulted from fatality, weight loss, growing weak calves and treatment costs. Hence, investigation of diarrhea causes in different areas is important to attempt management strategies to prevent and control it. OBJECTIVES: Present study was carried to investigate prevalence of some important entropathogens in diarrheic calves until three months old, in Shahrekord suburb husbandries. METHODS: Fecal samples were taken from 82 female calves in first day of diarrhea and were examined for isolation of salmonella, Escherichia coli, clostridium, cryptosporidium, and coccidia through common microbiological and parasitological methods. RESULTS: In general, prevalence of isolated organisms were: salmonella 36.6%, Escherichia coli 24.4%, clostridium 9.8%, cryptosporidium 9.8%, and coccidian 7.31%, and Escherichia coli K99 were isolated from four calves. The most prevalent pathogens were Escherichia coli and Salmonella. CONCLUSIONS: The calves are unavoidably exposed to infectious causes of diarrhea during their whole lifespan, because they acquire organisms from environment immediately after birth. Therefore, attempts at efficient management methods, hygienic principles and receiving enough colostrum, particularly in cold seasons, may be efficient in the control, prevention and decrease of diarrhea and its subsequent losses.

BACKGROUND: The mechanism of pathogenesis and the role of virulence factors of avian pathogenic E. coli is still ill-defined. The ostrich industry is expanding, resulting in the interaction between poultry and ostrich. It is reported that the investigation of iss and bor virulence genes together, due to their structural and functional similarities, is valuable. Objectives: The investigation and comparison of presence of two genes involved in serum resistance, iss and bor, in E. coli isolated from apparently healthy ostriches and poultry with colibacillosis. Methods: As a cross-sectional study, E. coli was recovered from fecal samples of apparently healthy ostriches and poultry with colibacillosis, and iss and bor genes were screened and compared via PCR in E. coli isolates. Results: iss frequencies, with no statistical difference, were 50% and 64.4% in E. coli isolated from apparently healthy ostriches and poultry with colibacillosis, respectively (P>0.05). 31.8% and 15.6% of E. coli isolated from apparently healthy ostriches and poultry with colibacillosis were positive for bor, respectively, with no statistical difference (P>0.05). 11.1% of isolates from colibacillosis and 18.2% of isolates from apparently healthy ostriches feces, with no statistical difference, were positive for both genes (P>0.05). Conclusions: Equal statistical distribution of both genes, bor and iss, between apparently healthy ostriches and poultry with colibacillosis and the health level of studied ostriches indicated that E. coli isolated from ostrich, probably employs other virulence factors instead of bor and iss to establish a disease. This hypothesis needs to examine more virulence genes in ostrich-origin E. coli. In addition, the ostrich feces could be introduced as a source of iss and bor genes.

BACKGROUND: Pigeons can be carriers for some human and animal pathogens, one of the most important of which is Escherichia coli. OBJECTIVES: This bacterium is responsible for outbreaks of many human diseases. Our objective was to determine the prevalence of Escherichia coli in cloacal area of pigeons in Tehran city (Iran), and determine  the prevalence of some virulence genes and also antibiotics resistance pattern of isolates. METHODS: Altogether 117 samples of pigeon feces were collected from cloacal swab. The identification of bacteria was done by culture on differential culture media. Then antibiotic susceptibility test was performed by disk diffusion method. Isolates were tested for the presence of virulence genes stx1, stx2, eae and hlyA using multiplex polymerase chain reaction. RESULTS: Escherichia coli were detected in 82.9% of 277 samples from pigeons. Sulfamethoxazole was the least effective drug (85.6% resistance), followed by tetracycline (83.5%). No resistance was detected to co-amoxiclav. The prevalence of stx1, stx2 and eaeA is 3.09%, 6.18% and 2.06% respectively and hlyA was not found in any of isolates. CONCLUSIONS: The frequency of stx1 and stx2 distribution in animals and birds is not well understood as yet. Due to the close relationship of humans with birds like pigeons and presence of STEC strains in apparently healthy birds, necessitates  considering  precise regulations to restrict and prevent the prevalence of this life- threatening virus in Iran.

BACKGROUND: Escherichia coli is a particularly complex species that is grouped into pathotypes of partly zoonotic intestinal pathogenic E. coli and extraintestinal pathogenic E. coli (ExPEC). Strains belonging to ExPEC are able to cause various clinical signs in hosts and due to similar genetic determinants, these hosts may act as a source of infection for each other. OBJECTIVES: Recent reports of outbreaks of human urinary tract infections (UTIs) have stimulated interest in the potential that E. coli from animals has to cause human UTIs via the food supply especially poultry meat, so we aimed to assess the genetic relationships between strains from these two hosts. METHODS: A total  of  260  E. coli  isolates  were  obtained  from human  UTI’s (160 strains) and  poultry colibacillosis cases (100 strains)  and  phylogenetic  grouping  was  done  based  on  the Triplex-PCR  method and virulence genotyping was carried out using a modified Tetraplex-PCR detecting hly, iucD, papEF and sfa/focDE genes. RESULTS: Statistical analysis of results demonstrated that prevalence of B2 &amp; D phylogroups in human UTI’s (77%) and D &amp; A groups in poultry strains (66%) are higher than others, considerably. Statistical analysis showed that distribution of A phylogroup within poultry isolates versus human and B2 phylogroup within human isolates versus poultry ones were higher, significantly. It was shown that iucD is noticeablymore prevalent in poultry strains rather than human isolates,. Also, sfa/focDE gene was significantly more distributed in human strains than poultry isolates. CONCLUSIONS: In sum, despite the minor genetic differences between isolates from both hosts, our results showed that there are major genetic similarities in E. coli isolates from human UTI and poultry colibacillosis cases in the region and these two hosts can play an important role as infection source for the other one.   ________________________________________________________________

Background: Colisepticemia is an acute fatal disease in farm animal neonates. Clinical finding of septicemia is non-specific and cannot be differentiate from signs of non-infectious disease or disease with local infection such as diarrhea. Object: Evaluation of clinical signs variations in calves with experimental septicemia with Escherichia coli O111:H8. Methods: Colisepticemia were experimentally induced in ten Holstein bull calves after an adaptation period. Vital signs and 7 clinical criteria were recorded from 24h before septicemia until 48h after that. Blood culture was performed and treatment was done based on antibiogram from 24h after challenge. Results: Changes of suckling reflex and shock were not significant. Changes of appetite, dehydration, behavior, standing ability, total score from 24h before the challenge to 24h after treatment were significant(P

BACKGROUND: AmpC and ESBLs as mediated-plasmid extended spectrum β-lactabases are the main factors of resistance to extended-spectrum cephalosporins in enterobacteriacea especially E. coli and will follow treatment failure, high costs of treatment in human and economic losses in the poultry industry. OBJECTIVES: The purpose of this study was to screen and study the faecal E. coli isolates producing extended spectrum β-lactamases (ESBLs) and AmpC enzymes and related workers. METHODS: A total of 500 cloacal swab samples from broiler chickens and 25 rectal swab samples from workers were collected from five poultry houses around Tehran. All samples were seeded on MacConkey agar and identification of E. coli isolates were performed via biochemical tests. Antibiotic susceptibility was determined against 12 antibiotics using the disk diffusion method as recommended by the clinical and laboratory standard institute (CLSI2012). Ceftazidim / ceftazidim-clavolanic acid and cefoxitin / cefoxitin-EDTA disks were used for the detection of ESBL and AmpC phenotypes, respectively. phonetic analysis of the drug resistances was performed via SPSS software and Chi-square test. ESBL- producing E. coli screened by PCR for the presence of genes encoding beta-lactamases of TEM, CTX-M and SHV.       RESULTS: A total 467 E. coli isolates were isolated from 88.9% of the samples as 92% and 72.7% of isolates presenting MDR phenotype among chickens and workers respectively. ESBL phenotype detected in 5.5% (26) of poultry isolates while, none of the workers isolates have this phenotype. Six isolates carried both of TEM and CTX-M whereas, five and one isolates were detected only for TEM and CTX-M, respectively. Eighty-eight and nine-tenths percent of ESBL E. coli displayed AmpC phenotype. CONCLUSIONS: Since cephalosporins are not used in broilers in Iran, isolation of faecal E. coli isolates producing extended spectrum β-lactamases in broilerchickens can indicate transfer of the resistance genes via plasmids and other mobile genetic elements among Enterobacteriaceae.