IRANIAN JOURNAL OF MEDICAL MICROBIOLOGY
Year:2018 | Volume:12 | Issue:4 |Papers Count:10

Many of the texts referenced by faculty members and medical students are from foreign sources and references, and the history of contagious diseases and the unique role of the country's scientists in the identification, treatment and control of these diseases has been forgotten. This paper attempts to review the history of prevalent bacterial infections in Iran. In this regard, it was attempted to review the scientific literature, including historical books and articles, with the historical background of prevalent bacterial infectious diseases such as cholera, leprosy, plague, tuberculosis, etc., as well as those who are hard-working and have played a significant role in difficult conditions trying to reduce the suffering of the people at that time. A review of the history of prevalent bacterial infectious diseases in Iran leading to the historical background of these diseases to be detailed in the book "History of Microbiology and Bacterial Infectious Diseases in Iran" is under the supervision of the Academy of Medical Sciences. Editing of scientific resources and academic books related to this issue should be based on the history of prevalent infectious diseases in Iran, so that in the future this historic cultural disadvantage would be corrected in an appropriate way.

Background and Aims: Salmonella Spp. is one of the most common causes of bacterial gastroenteritis and foodborne diseases. More than 2500 serotypes of Salmonella have been identified which most of them cause infections in humans. Phylogenetic analysis of the family Enterobacteriaceae has not been subjected to extensive variation based on 16S rRNA sequences. In fact 16S rRNA gene was not thought to solve taxonomic problems concerning closely related species because of its highly degree of conservation in own structure. So, 23S rRNA gene which has a potential to classified related strains under sub-species level were candidate to analysis of Salmonella spp. The aim of this study was to evaluate the clinical Salmonella strains’ relationship using 23S rRNA gene sequence. Materials and Methods: DNA of identified Salmonella spp. from patients with acute diarrhea was extracted. Sequences of 23S rRNA were determined after PCR tests. The whole gene sequences were used to generate phylogenetic trees based on Neighbor-joining method by MEGA 5. 05 5. Results: Helix (25 and 45) structures were detected in the most of different serotypes isolates. All S. Typhi included helix-25 in ribosomal structure, but in the other strains, helix-45 was also observed. The similarity between Salmonella spp. was 99-100% based on 23S rRNA. Conclusions: 23S rRNA gene sequence data was better to analyze at subspecies level and differentiation between serovars. According to variety in Salmonella serotypes based on difference in Anti gene O and H, application of new molecular methods and substituting them with traditional assays are needed.

Background and Aims: Pseudomonas aeruginosa is an opportunistic pathogen that causes serious infections and high mortality among burn patients. The aim of this study is to evaluate the protective effects of a candidate divalent vaccine containing type A flagellin and pilin of P. aeruginosa in a burn wound mouse model. Materials and Methods: Recombinant flagellin A and pilin proteins were generated by expressing fliC and pilA genes (cloned in pET-28a and pET-22b vectors, respectively) in E. coli BL-21. Groups of mice were immunized by injection of 10 μ g of either flagellin A and pilin, or flagellin A, or pilin. Specific IgG titer was measured by ELISA. The functional activity of antibodies was evaluated by opsonophagocytosis assay. The protective effects of the vaccine were evaluated by measuring mortality and bacterial load in mice. Results: Immunization with flagellin A and pilin mixture significantly increased the specific IgG antibody titer as well as opsonophagocytosis compared to monovalent antigens (P<0. 05). Immunization with flagellin A and pilin mixture significantly reduced the bacterial load, and increased the survival of mice challenged with P. aeruginosa, as compared to the monovalent antigens (P<0. 05). Conclusions: Immunization with flagellin A and pilin mixture provides effective protection against P. aeruginosa wound infection in burned mice. Reduced bacterial load, and high survival rates among immunized mice suggest that flagellin A and pilin candidate vaccine shows therapeutic potential against P. aeruginosa infections among burn patients

Background and Aims: The virulence plasmid of the Gram negative pathogen Shigella generates many virulence factors within the Ipa-mxi-spa region. Shigella spreads via fecal-oral and person-to-person transmission which causes human bloody diarrhea. In Asia alone, it is estimated that there are 125 million infections and 14, 000 deaths due to shigellosis annually. IpaB is essential for Shigella infection and pathogenicity. Materials and Methods: Expression plasmid based on the araBAD promoter is designed for tight control of background expression and l-arabinose dependent graded expression of the target proteins. IpgC and IpaB genes were amplified using polymerase chain reaction (PCR) with designed primers. In the next step, the products were then cloned into pBAD/myc-HisB expression vector. The presence of the insert was confirmed by restriction digestion. In order to confirm the chaperone role of IpgC on IpaB protein stability, the 300-bp is removed from the Nterminal portion of IpaB and His6-tagged CPD is fused to the C-terminus of target proteins in the pET28b. Results: The construction of IpaB gene expression plasmid and expression of IpaB protein was achieved. Also, expression of the gene truncation of IpaB along with the His6 tag sequence in the absence of the IpgC gene in Escherichia coli revealed that the role of the IpgC chaperone gene on IpaB expression can be considered as an appropriate strategy for expression of IpaB. Conclusions: In the present study IpgC and IpaB genes were successfully cloned and expressed under the control of arabinose-dependent promoters to provide IpaB expressing plasmid. The role of the IpgC as a chaperone protein on IpaB expression and stability can be considered as an appropriate strategy for expressing IpaB. The induced vector can be used for future analysis of Shigella vaccine development.

Background and Aims: Diarrhea caused by intestinal bacteria is a major cause of mortality, especially in children under the age of five in developing countries. Vaccines can be considered as an important solution to prevent these diseases. Toxin-coregulated pilus (TcpA), OMPW and cholera toxin are the most important virulence factors of vibrio cholera and have immunogenic characteristics. In this study, a recombinant immunogen consisting of TcpA, Outer Membrane Protein OMPW, and cholera toxin B-subunit (CtxB) was designed. This chimeric protein, which contains B-cell epitopes and an adjuvant sequence, can potentially increase the likelihood of developing effective immune responses. Materials and Methods: To increase the probability expression of the OTC protein, gene codons and various parameters effective in expression were optimized. The thermodynamic analysis of the mRNA structure was performed to verify stability. The third structure of the protein was predicted and the quality of the structures was evaluated. Linear and conformational epitopes were also determined. Results: Protein with the sequence of OTC showed the highest antigenicity index. Codon Adaptaion Index of chimer increased to 0/89. The third predicted structure based on the RaptorX server showed good quality. The thermodynamic analysis of the mRNA structure showed that the predicted structure is stable. Conformational and linear epitopes were observed in all three domain of chimeric protein. Conclusions: The results showed that the protein produced from this structure could act as an immunogen against the binding and toxin function of Vibrio cholera bacteria.

Background and Aims: Probiotics are useful microorganisms for health of communities. Saccharomyces cerevisiae is one of the effective microorganisms for treating of functional and gastrointestinal diseases in order to control pathogens. Enterohemorrahgic Escherichia coli (EHEC) and Enterotoxogenic (ETEC) are common pathogenic strains in all the world. The aim of this study was to evaluate the inhibitory effect of S. cerevisiae probiotic yeast on the growth of ETEC and EHEC. Materials and Methods: For preparation of the supernatant extract, the yeast suspension was centrifuged, and then, the supernatant was filtered. Extraction with ethyl acetate was performed in three hours. For preparation of lysate, the precipitate was washed and centrifuged. The supernatant was removed and sterilize distilled water was added. Cell lysis was performed by sonication and the liquid was centrifuged and filtered. Then, the MIC and MBC were determined by micro dilution method. The concentration range was 16-8192 μ g/ml. Results: The MIC and MBC of the supernatant against both ETEC and EHEC were 4096 μ g/ml and 8192 μ g/ml, respectively. Lysate in any of the concentrations showed no inhibitory effects on strains. Conclusions: The supernatant of S. cerevisiae has an inhibitory effect on growth of ETEC and EHEC. The lysate, probably due to the richness of the nutrients required for bacterial growth and not containing antibacterial compound, did not lead to such a repressive effect.

Background and Aims: Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli are the most important bacteria responsible for hospital infections with multiple antibiotic resistance. Problems in the treatment of infections caused by resistant isolates have been the factor for the investigation of alternative drugs, including medicinal plants. Materials and Methods: In this experimental study, antimicrobial activity of aqueous and alcoholic extract of Garlic and Aloe vera on 63 strains of P. aeruginosa, S. aureus and E. coli isolated from clinical specimens were investigated. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) was carried out by tube dilution method. Results and Conclusion: In the MIC test, E. coli isolates showed the most sensitivity to the aqueous (with mean MIC, MBC 236. 8 and 473. 6 mg/ml, respectively) and alcoholic extract of the Garlic (with mean MIC, MBC 329. 6 and 659. 2 mg/ml, respectively) (P<0. 05). Clinical isolates of S. aureus showed the highest susceptibility to garlic alcoholic extract, followed by aqueous extract of garlic and alcoholic extract of aloe vera (with mean MIC, 156. 8, 188. 8 and 198. 4 mg/ml, respectively). The results showed that the isolates of P. aeruginosa were resistant to both garlic and aloe vera extracts. Considering the significant antibacterial effects of alcoholic and aqueous extracts of garlic and alcoholic extract of aloe vera on pathogenic bacteria, that contribute to the development of various types of infectious and nosocomial infections, these extracts can be considered as natural and alternative drugs.

Background and Aims: The monitoring of the causative agents of nosocomial infections (Nis), particularly in the Intensive Care Unit (ICU) ward to detect any change in pattern of infection and their resistance profile are crucial. The aim of this study was to investigate the antibiotic resistance pattern among Gram-negative rods isolated from inpatients in different wards of ICU in Shiraz, Iran. Materials and Methods: In this cross-sectional study from Jaunary to June 2017, 91 different clinical samples were collected from Nemazi teaching hospital ICU wards. After confirming all the isolates by the conventional microbiologic methods, their antimicrobial susceptibility pattern against 11 antibiotics were investigated using the disk diffusion test. Extended-spectrum β-lactamase (ESBL) production was also examined. Results and Conclusions: The isolated bacteria were Acinetobacter baumannii (n=72, 79. 1%), Pseudomonas aeruginosa (n=14, 15. 4%), and Escherichia coli (n=5, 5. 5%). The highest and the lowest resistance rates were observed against ampicillin (100% and 95. 8%) among P. aeruginosa and A. baumannii and imipenem and amikacin (0%) among P. aeruginosa and E. coli isolates, respectively. The frequency of multidrug-resistant (MDR) and ESBL-producing isolates was found 84. 6% and 19. 8%, respectively. Of the MDR isolates, 23. 4% were ESBL producers. A significant difference was determined between ESBL production and MDR isolates. Regarding the high rate of antimicrobial resistance among clinical isolates in the study area, the antibiotic susceptibility results may be a useful guide for empirical therapy used by physicians.