Crown gall caused by Agrobacterium spp. has been observed in various crop species and in several provinces of Iran in recent years. In an attempt to identify the Agrobacterium species causing the disease in different areas of the country, STRAINS were isolated from various infected crop species and characterized by phenotypic features, electrophoretic profile of cell proteins and BOX IR fingerprinting.On the basis of their phenotypic features, the STRAINS were differentiated into three separate groups. The phenotypic characteristics of the first group of STRAINS were closely similar to those of A. tumefaciens (Rhizobium tumefaciens). Members of the second group, isolated from infected grapevines were also identified as A. tumefaciens. STRAINS of the third group were phenotypically different from all described species, but appeared to be more similar to A. tumefaciens. These STRAINS were not able to grow on any of the selective media tested and displayed a limited host range, infecting mainly sweet cherry All STRAINS had a similar plasmid profile. The electrophoretic profile of cell proteins of the STRAINS was different, although some similarity of the pattern was noted in the high-molecular weight region. In fingerprinting using BOX IR primer, a high level of heterogeneity was observed, nonetheless two major groups were differentiated. Phenotypic features appeared to be reliable criteria in identification of Agrobacterium species encountered in this study.

Background: Hospital-acquired infections are a major challenge to patient. A range of gram-negative organisms are responsible for hospital-acquired infections, the Enterobacteriaceae family being the most commonly identified group overall. Infections by ESBL producers are associated with severe adverse clinical outcomes that have led to increased mortality, prolonged hospitalization, and rising medical costs. The aim of this study was to survey profile of antimicrobial susceptibility isolated microorganisms from hospitalized patients in PICU ward and detection of methicillin-resistant Staphylococcus aureus and ESBL-producing bacteria by phenotypic methods.Material and Methods: In this study participants were patients hospitalized in PICU part of Bahrami Hospital, Tehran, with attention to involved organ. For isolation of bacteria from patient’s samples, culture performed on different selective and differential media. After confirmation of bacteria by biochemical tests, susceptibility testing was performed by disc diffusion method. Phenotypic detection of MRSA STRAINS was performed using cefoxcitin disc. ESBL producing STRAINS were detected by ceftazidime (CAZ) and ceftazidime/clavulanic acid (CAZ/CLA) discs.Results: Among all isolated organisms from clinical samples, the most common isolated organisms were Escherichia coli (24 cases), Pseudomonas areoginosa (9 cases) and Staphylococcus aureus (8 cases), respectively. Among eight MRSA isolated STRAINS from different clinical samples, six STRAINS (75%) were MRSA. Among 52 isolated gram negative organisms, 5 STRAINS (9/6%) were ESBL.Conclusion: Standard interventions to prevent the transmission of antimicrobial resistance in health care facilities include hand hygiene, using barrier precautions in the care of colonized and infected patients, using dedicated instruments and equipment for these patients. The colonized or infected patients should be isolated in single rooms, multibed rooms or areas reserved for such patients. Active surveillance screening is necessary to identify asymptomatically colonized patients who may serve as undetected reservoirs.

Introduction: Despite high level of vaccination against pertussis‚ whooping cough has re-emerged as a health threat, especially in infants. This could be related to expansion of Bordetella pertussis with novel alleles for virulence factors including the pertussis toxin promoter, ptxP3. Compared to ptxp1 STRAINS‚ ptxp3 STRAINS produce more pertussis toxin which results in immune suppression and virulence. The main aim of this study was the determination of dominant alleles of the promoter region of the gene coding for pertussis toxin in B. pertussis isolates in Iran. Methods: In this project, we studied the allelic variations in ptxP3. This factor was sequenced and analyzed in 35 B. pertussis isolates from Iranian patients in 2011. Biochemical tests were performed to confirm the B. pertussis isolates. Ultimately, polymerase chain reactions and sequencing were done. Results: Our results showed that the predominant allele among the STRAINS was ptxP3. One isolated strain (i. e. ptxP1) showed different results from the other STRAINS. Also, B. pertussis 134 and 509 as common vaccine STRAINS used in Iran were analyzed and they were identified to be ptxP1. Conclusion: Based on our results in recent years‚ the vaccine STRAINS and the circulating STRAINS do not share the same alleles which could be one of the causes of pertussis resurgence in the world. ptxP is a well-known toxin of B. pertussis which is responsible for binding to the host cell and the disruption of the cellular function. In particular‚ allelic variation in ptxP may play a role in adaption of B. pertussis.

Background: There is an increasing interest in search for antimicrobial peptides (bacteriocins and bacteriocin-like compounds) produced by lactic acid bacteria (LAB) because of their potential to be used as antimicrobial agents for improving the safety of food products.Objectives: The main objective of study was to evaluate the antibacterial potential of locally isolated Lactic Acid bacteria (LAB) and determine their bacteriocin producing ability in in-vitro conditions.Materials and Methods: The antibacterial activity of 77 isolated LAB STRAINS was tested against a number of pathogens by well-diffusion method. The isolates demonstrating antimicrobial potential were selected and tested for the production of bacteriocin or bacteriocin like substance. The bacteriocin produced by two of the isolates were partially purified and characterized.Results: The results indicated the neutralized supernatant fluid of two of the isolates identified as L. brevis LB32 and L. pentosus LP05, were active against the growth ofListeria monocytogenes, Salmonella enteritidis, Shigella dysenteriae, Staphylococcus aureus and Streptococcus pneumoniae. Additionally, L. brevis LB32 was able to inhibit the growth of Salmonella typhi and Klebsiella pneumoniae, while, S. pnuemoniae andL. monocytogenes appeared to be the most sensitive strain as apparent by highest zone of inhibition against these pathogens, respectively. The antimicrobial activity in the supernatant fluids of the mentioned STRAINS remained unaffected after treating with enzymes catalase, lipase and lysozyme, while were strongly sensitive to the action of proteolytic enzymes, suggesting the presence of bacteriocin like inhibitory substance (BLIS) in the two isolates. The inhibitory substance produced by the two isolates appeared heat resistant and tolerated 100˚C and 121˚C for 55 minutes and 20 minutes, respectively. Partial purification of the concentrated culture supernatant fluids ofL. brevis LB32 and L. pentosus LP05 by ammonium sulphate (80%) and DEAE cellulose columns resulted in an enhanced activity (AU/mL) and yield. Using different pore size ultra filter membranes and SDS-PAGE analysis, the approximate molecular weight of the BLIS produced byL. brevis LB32 and, L. pentosus LP05 appeared to be approximately 4.5 and 6 KDa, respectively. In contrast to L. brevis LB32, L. pentosus LP05 harbored an 18Kb plasmid DNA which appeared to be carrying the bacteriocin gene as evident by plasmid curing experiments. All the mutants retained their host immunity and were resistant to the bacteriocin produced by the parent strain.Conclusions: In conclusion, the antibacterial activity possessed by these isolates might be used for the control of unwanted pathogens mainly in dairy products, and could be investigated further for using in fermented dairy products.

Objective(s): Virulent STRAINS of Pseudomonas aeruginosa exhibit multidrug resistance by intrinsic and extrinsic mechanisms which are regulated by quorum sensing signalling systems. This includes the production of auto-inducers and their transcriptional activators to activate various virulence factors resulting in host infections. The present study is thus aimed to detect the virulence factor production, quorum sensing activity, and susceptibility pattern of P. aeruginosa to antibiotics from clinical specimens. Materials and Methods: A total of 122 isolates of P. aeruginosa were phenotypically characterized by standard protocols and were categorized into MDR and non-MDR based on the antibiotic susceptibility profiles. Pyocyanin, alkaline protease and elastase production were assessed by qualitative and quantitative methods. Crystal violet assay was carried out for the quantification of biofilms. The genetic determinants of virulence were detected by PCR. Results: Out of the 122 isolates, 80. 3% of isolates were MDR and the production of virulence factors was in positive correlation with the presence of genetic determinants and 19. 6% were non-MDR, but still showed the production of virulence factors, as confirmed by both phenotypic and genotypic methods. Few carbapenem-resistant STRAINS were detected which did not show the production of virulence factors by both methods. Conclusion: The study concludes, though the STRAINS were non-MDR, they were still capable of producing the virulence factors which may be responsible for the dissemination and chronicity of the infection caused by P. aeruginosa.

Newcastle disease is one of the main concerns of poultry farmers. Detection of virulent STRAINS of Newcastle disease virus (NDV) has a great impact on control measures against the disease. In this study RT-PCR was optimized in high sensitivity in order to differentiate the virulent from non-virulent NDV isolates directly in tissue homogenates. The vaccinal NDV strain and known field isolates were tested by this technique. RT-PCR was performed using two sets of primers chosen from a section of the F gene. The PCR product was cloned in to a pTZ57R/T vector and sequenced. The sequence data confirmed the specificity of the test. Detection of viral virulence was determined based on the amplification of PCR products. The above optimized RT-PCR produce can be used to confirm the diagnosis of Newcastle disease within 24 hrs using RNA isolated directly from tissue homogenate or passaged in SPF (Specific Pathogen Free) embryonated eggs.

Background: The present study aimed to evaluate the in vitro and in situ antagonistic effects of Lactobacillus probiotic STRAINS on clinical STRAINS of Helicobacter pylori. Also to investigate their immunomodulation effects on a macrophage cell model. Materials and Methods: Anti-microbial effects of probiotic lactobacilli against H. pylori was assessed using the well and disk diffusion methods. Effects of lactobacilli probiotics STRAINS, as well as their cell-free supernatant on adhesion of H. pylori to MKN-45 gastric epithelial cells, were examined in their presence and absence. Immunomodulation effects of probiotic lactobacilli were performed using the U937 macrophage cell model. Incubation of host cells with probiotics and their cell-free supernatants with cultured host cells was performed in different optimized conditions. The supernatant of host cells cultured in their presence and absence was used for cytokines measurement. Results: Two probiotics, Lactobacillus acidophilus ATCC4356, and Lactobacillus rhamnosus PTCC1607, could inhibit the growth of clinical H. pylori in vitro. They could also inhibit attachment of H. pylori to MKN-45 cells. Cell-free supernatant of L. acidophilus had a stimulating effect on the production of Interferon-gamma (IFN-γ ) by U937 cells. Conclusion: The present study demonstrates that, L. acidophilus ATCC4356 and L. rhamnosus PTCC1607 probiotic STRAINS can inhibit the growth of clinical H. pylori in vitro. Treatment of U937 with alive H. pylori plus cell-free supernatant of L. acidophilus, have a significantly higher capacity to stimulate IFN-γ production than H. pylori alone. So, the metabolite (s) of this probiotic may have an immunomodulatory effect in immune response versus H. pylori.

Background and objective: Lactic acid (2-hydroxypropionic acid, CH3CHOHCOOH) is a naturally occurring, chiral, alpha-hydroxy acid and has L(+) and D(-) optical isomers. It is used in food processing (as an acidulant and preservative), medicine, agriculture, and leather and textile industries. Due to its chiral properties, L-lactic acid is used in the pharmaceutical industry as an intermediate for the synthesis of chiral drugs. Polymers of lactic acid are biodegradable and have found use in manufacturing medical equipment. Although several STRAINS of microorganisms are capable of producing lactic acid, some STRAINS of Lactobacilli are generally recognized as safe (GRAS) in this regard.  In the present study five lactobacillus STRAINS were studied in order to determine the best L(+)lactic acid-producer strain.Materials and Methods: The lactobacillus STRAINS were obtained from the Persian Type Culture Collection (PTCC), Iranian Scientific and Industrial Research Organization. They were cultured, under sterile conditions, on the slants of de Man, Rogosa and Sharp (MRS) agar, followed by inoculation on MRS broth medium as a preculture. Then 2.5-ml samples of the preculture containing 108 cells/ml were inoculated in 250-ml Erlenmeyer flasks containing 50 ml of a production medium. Fermentation was carried out at 30oC and 180 rpm on a rotary shaker incubator, and glucose consumption, lactic acid production, and growth of the STRAINS were measured in triplicates every 8 hours.Results: L. casei subspp. casei produced 95 g/l calcium lactate.  The yield and productivity of this strain on optimized media containing 100 g/l glucose were 95% and 0.98 g/lh, respectively. The other high-lactate producer was L. rhamnosus which produced 81.40 g/l calcium lactate, the yield and productivity being 63% and 0.85 g/lh, respectively.Conclusion: L. casei subspp. casei PTCC: 1608 and L. rhamnosus PTCC:1637 are the best L(+) lactic acid-producers. They are, thus, the best bacterial strain candidates for pilot plant studies of lactic acid production.