JOURNAL OF MICROBIOLOGY KNOWLEDGE
Year:2010 | Volume:2 | Issue:6|Papers Count:12

Pseudomonas aeruginosa is a nosocomial pathogen naturally recalcitrant to many antibiotics. Over the past decade, it has been realized that this poor drug susceptibility in part relies on the activity of active efflux system, namely MexXY-OprM. The MexXY-OprM system is unique in P. aeruginosa in that the mexXY operon is induced by exposure to many of the antibiotics that this efflux system exports. It is interesting that not all antibiotic substrates, but only those agents known to target the ribosome, induce mexXY expression.102 isolates collected from burn hospital and  58 isolates identified as Pseudomonas aeruginosa .The isolates were identified by biochemical tests and then Susceptibility to antibiotics was performed. The MDR isolates selected for PCR and MICs determination. The most percentage of resistance to gentamicin, tobramycin, amikacin and ciprofloxacin observed. Presence of mexX gene demonstrated in MDR(multidrug resistant) starins. According to the observation about presence of mexX gene of MexXY-OprM system, we concluded that in these clinical isolates it was probably high expression of MexXY-OprM. Since the results of drug profiling suggested the expression of the MexXY–OprM efflux.

Leptospirosis is a zoonosis disease that caused by pathogenic serovars of Leptospira which spreads in tropical countries. Detection of leptospira from the sample by the culture is time consuming and molecular methods like PCR are rapid and suitable method. The aim of this study is prepare the best lyses buffer for using in leptospira DNA extraction. The pathogenic serovars of leptospira cultured on EMJH medium and pellet of the bacteria were collected. Three lysis buffers, Lep1, Lep2 and Lep3 were made for the extraction of leptospiral DNA by using phenol- chloroform-isoamyl alcohol. The extracted DNA was analyzed by Spectrophotometer, agarose gel electrophoresis and PCR. The results showed that Lep1 lysis buffer has the best quality of extracted DNA. Moreover, the results of PCR showed that extracted DNA with Lep1 lysis buffer was more suitable for PCR.

Infections with Mycoplasma species can induce a variety of problems in living organisms and in in vitro cell cultures. These non-apparent infections tend to be quite insidious, as they may affect a variety of biochemical and genetic aspects of the infected cells, thereby resulting in unreliable experimental results and the possible transmission of diseases. Therefore, it is necessary to establish a routine diagnostic protocol for Mycoplasma infection in order to ensure reliable research results, as well as the safety of commercial biological products. However, the detection of Mycoplasmic species in cell cultures and another biological product remains a problem. The majority of currently available detection procedures are not sufficient for the simultaneous detection of the major Mycoplasma species contaminants commonly encountered in in vitro cell cultures. In order to circumvent those limitations, many nucleic acid technology-predicated procedures have been developed. PCR-based methods for the detection of certain DNA regions of the Mycoplasma genome have proven both rapid and specific. Using SHAH-GPO-3, MGSO primers and standard Mycoplasma species PCR optimized and sensitivity and specificity evaluated by Known CFU samples and different strains. Cell culture DNA extracted and then tested by optimized PCR. Amplicon (272 bp) cloned by PCR-cloning and then sequenced by di-deoxy chain termination. In this study, we describe our newly-developed sensitive PCR procedure for the detection of Mycoplasma genus contaminants. For amplification, the DNA regions of 16SrRNA were targeted using general Mycoplasma primers. The PCR, which generated DNA fragments of 272 bp, was found to be able to detect 10 copies of the target DNA, and evidenced no cross-reactivity with the genomic DNA of related microorganisms or of human cell lines, thereby confirming the sensitivity and specificity of the primers used. 25 from 47 cell lines infected with Mycoplasma. The results obtained in this study furnish evidence suggesting that the employed assay system constitutes an effective tool for the diagnosis of Mycoplasmal contamination in cell culture and another biological system.

Stability of resistant to antibiotics in bacterial pathogens has created a serious crisis in public health. Prevalence of plasmids containing silver and antibiotic resistance in Pseudomonas aeruginosa strains is threat for control and treatment of nosocomial infection injured. In this study, after isolation and identification of clinical resistant strains from burn wounds, MIC of silver nitrate for strains isolated have been established. Presence of the silS genes in isolated plasmid strains has been evaluated through Polymerase chain reaction technique. From 70 bacterial strains isolated about 85% of strains were found with MIC 0.01-35 mg/ml of silver nitrate. 36% of strains resistant to silver. Presences of silS genes with 1500 base pair molecular weight were approved in 3% 0f isolated plasmids of Pseudomonas aeruginosa strains. This review was determined that silver nitrate resistance was associated with antibiotic resistance in several strains and not found in any sensitive strains of Ps. aeruginosa. The indiscriminate use biocides silver-containing compounds resulting in increased antibiotic-resistant strains and the treatment of burn infections serious problems with making.

The aim of this study was cloning diphtheria toxin gene to produce recombinant protein and application in next investigations. PCR was carried out using dt gene specific primers. This gene was cloned in pTZ57R/T vector and sub cloned into pETDuet-1 expression vector. Diphtheria toxin gene was amplified successfully and cloned in pTZ57R. Recombinant plasmid was digested by restriction enzymes and released fragment (diphtheria toxin gene) sub cloned in pETDuet-1 expression vector. In this study, the diphtheria toxin gene was cloned in expression vector and confirmed, and then it became ready to make recombinant protein. It can be used in next investigations.

Polycyclic aromatic hydrocarbons (PAHs) are important contaminants and carcinogenic. In most cases these contaminants such as anthracene, naphthalene and benzene are released in the wastewater of petroleum and petrochemical industries, which could cause a great damage to environment. In order to remove these substances from soil, some biological methods along with potential of contaminated soil's microorganisms are utilized. These microorganisms metabolize the contaminants as carbon source and yield water, carbon dioxide and biomass. In this study the capability of isolated microorganisms from soil in some fields of East Azerbaijan has been investigated. The Microorganisms were isolated and purified in YGM culture medium. Naphthalene (for model of PAHs) with concentration 1000mgL-1 was prepared in Mueller Hinton Broth and constant amount of bacteria was added and kept for one week at 28o Cand 120 r.p.m. Then the destruction level was evaluated with double beam spectrophotometer. Forty types of bacteria were isolated and in the above concentration destruction level was achieved from (9.2-92.9) percent. The results also revealed that 6 types of bacteria had over 50% destruction. Therefore this method is useful for removing PAHs from contaminated oily solid.

Probiotics are live microorganism that when administered in amounts confer a health benefit on the host .In these years preparation of food and beverage with probiotics was very attractive. In this study the Persian yellow carrot juice was inoculated by 4 species of Lactobacilli. Yellow carrot juice was sterile by 1100C, 10 min then inoculums 104 CFU/ml of Lactobacillus. Kinetic of Lactobacilli growth in the yellow carrot juice were measured every 2 hours. The results were defined that every 4 species could growth in Persian yellow carrot juice. Survival of inoculated Persian carrot juice by probiotics was measured in 4, 25 and 370C. Changes of pH, glucose, Lactic acid were measured during 97 days in inoculation Persian carrot juice by probiotics. The results were showed that 40C was the best temperature for Lactobacillus, amount of Lactobacillus. Lactobacillus acidophilus had be best growth and survival in the Persian yellow carrot juice.

Preservatives are needed to prevent microbial contamination during the production and using of cosmetic products. In this study was investigated antimicrobial potency of benzoate sodium of %0.1 that is a chemical preservative and silver nanoparticles of 0.4 ppm in mouthwash. Antimicrobial effects of two treatments were studied by doing challenge test on gram positive bacteria such as Streptococcus mutans, Staphylococcus aureus and gram negative bacteria including Escherichia coli, Pseudomonas aeruginosa and Candida albicans as a yeast. Results of challenge test showed a significant difference between antimicrobial effect of silver nanoparticles (0.4 ppm) and Benzoate sodium of %0.1 on used microorganisms excepting S. aureus and S. mutans (P>0.05). In conclusion, results showed that silver nanoparticles have strong antimicrobial property at low concentration and their antimicrobial activity is stronger than Benzoate sodium or is as strong as Benzoate sodium, also antimicrobial effect of is increased when two treatments are used together in mouthwash.