Vol 8 No 3-4 (2019)

Published: 2019-06-12

Original Articles

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    Background:   In a survey of milk samples obtained from individual farms and pasteurized milk plants in Ardabil city, 38% of raw milk samples and 22% of pasteurized milk samples were found to be contaminated with Bacillus cereus. In total 200 milk samples,100 of raw milk and 100 of pasteurized milk, were tested for the presence of B. cereus contamination.  Methods:   The milk samples tested positive for B. cereus were used to isolate the DNA from the and subsequently used in molecular genetic analysis. Statistically, 38% of raw milk samples and 22 % of pasteurized milk samples were found contaminated with B. cereus. The results of the present study confirms that processed milk also carries a very high probability of B. cereus  contamination .In the present study,  three different primer sets  were used to amplify DNA obtained from B. cereus isolates and the gene expression profile of beta-lactamase producing genes (SHV,TEM,CTX-M) were analyzed using PCR. Results:   TEM types of beta-lactamases exhibited maximum percentage frequency in raw milk isolates whereas pasteurized milk isolates had the most frequency of CTX-M type of beta-lactamases. It was observed that both raw and pasteurized milk are a source of B. cereus as evident by pure isolates obtained on agar plates. Conclusion:    The gene expression profile shows that milk samples are frequently contaminated with antibiotic resistant strains of B. cereus.
  • XML | PDF | downloads: 143 | views: 303 | pages: 8-17
    Background:   Listeria monocytogenes infection during pregnancy may cause spontaneous abortion or stillbirth, or the birth of babies with neonatal meningitis. The aim of this study was to serotype L. monocytogenes isolated from women with spontaneous abortion using polymerase chain reaction. Methods:  Vaginal swab samples were obtained from 96 women with spontaneous abortion. The microbial culture was performed on blood agar and PALCAM agar followed by differential biochemical tests for characterization of L. monocytogenes isolates. Besides, total DNA was extracted from each vaginal specimen, and PCR assay was then carried out using specific primers for target genes of this bacterial species. Results:    Microbial culture and PCR revealed 4 and 16 L. monocytogenes isolates (out of 96 vaginal specimens), respectively. There was a significant association between consuming unsterilized dairy products and the risk of Llisteria infection (P < 0.001). Various serotypes of L. monocytogenes were detected as follows; the serotypes 1/2b, 3b (31.25%), the serotypes 1/2c, 3c (31.25%), the serotypes 1/2a, 3a (25%), and the serotypes 4 (12.5%). Conclusion:   However, the difference between frequencies of observed serotypes was not statistically significant (P < 0.05). The 1/2b, 3b, and 1/2c, 3c serotypes of L. monocytogenes are more commonly seen in vaginal specimens of women with spontaneous abortion, and PCR technique as a convenient tool may be used for identifying of causative strains. However, further studies need to improve and optimize this approach.
  • XML | PDF | downloads: 204 | views: 315 | pages: 18-22
    Background:    Acinetobacter baumannii is one of the important causes of nosocomial infection worldwide. Patients who use ventilator are in high risk of ventilator association pneumonia (VAP) caused by nosocomial pathogens such as A. baumannii.  Carbapenem is one of the last lines of antibiotic therapy in MDR A. baumannii infections. Then, carbapenem resistant strains are a very important challenge for physicians. OXA types carbapenemase enzymes are important mechanisms to carbapenem resistance in A. baumannii. The aim of this study was to determine oxa-23 and oxa-48 producing A. baumannii isolated from VAP.  Methods:      In this cross-sectional study, 51 sputum specimens from VAP in hospitalized patients in Hazrat-E-Rasul Hospital, Tehran, Iran were used. Antibiotic susceptibility testing was done after identification according to CLSI 2018. DNA extraction was done by boiling assay and oxa-23 and oxa-48 genes were detected by PCR. Thirty- two (63%) A. baumannii were confirmed according to microbiological and biochemical tests.   Results:      The highest resistance was observed against Piperacillin, Cefotaxime, Ciprofloxacin and Ceftazidime with 97% antibiotic resistance, and ampicillin/Sulbactam was the most effective antibiotic (78% sensitivity). Generally, 31 isolates of A. baumannii harbored the oxa-23 gene and none of them had oxa-48. The high prevalence of MDR A. baumannii in VAP is a great problem, especially for the nosocomial infection committee in hospitals. Conclusion:      Rapid detection of MDR and carbapenemase producing strains can be the first step in preventing their spread in hospitals. 
  • XML | PDF | downloads: 182 | views: 226 | pages: 23-30
    Background:     Multidrug resistance is a serious problem in the treatment of urinary tract infections. Integrons are ancient structures that contain determinants of a site-specific recombination system to capture genes encoding antimicrobial resistance. The aim of this study was to determine the prevalence of multidrug resistant Klebsiella isolates in clinical specimens. In addition, the existence of integrons in resistant isolates was assessed by amplification of integrase genes. Methods:   Susceptibility of 100 Klebsiella isolates was determined to 19 antibiotics by the Kirby-Bauer disc diffusion method and integron classes were detected. Then the multi-drug resistance association with the existence of the integrase gene was calculated by chi-squre and fisher exact tests. Results:    According to antibiogram results, 54 isolates were multidrug resistant. By amplification of intergrase gene it was revealed that 27% of the isolates harbor integrons. Also by PCR-RFLP it was revealed that all of them were class 1. The existence of integrons was confirmed in 25 of our multidrug resistant isolates, indicating the frequency rate is high and integrons may be partly responsible for multidrug resistant. Conclusion:   Multidrug resistance suggests that strategy for treatment of patients with Klebsiella infections needs to be revised. The possibility of transmission of resistance genes by integrons would be decreased by treatment of patients with the appropriate antibiotics.
  • XML | PDF | downloads: 221 | views: 304 | pages: 31-39
    Background:    Salmonella enterica is a zoonotic species that can acquire its resistance in livestock. In humans, Salmonella typhimurium is a major etiological agent of food-borne salmonellosis. The identification of Salmonella spp. by traditional cultural techniques requires 4 to 5 days. The polymerase chain reaction (PCR) offers a simple tool for the rapid detection of Salmonella. Methods:     Fifty-five S. typhimurium isolates from bovine, poultry and human sources were isolated and analyzed with biochemical and serological tests. Firstly, multiplex PCR assay with four sets of primers was selected for invA, rfbj, fliC and fljB genes. In the second stage, a simple PCR method with one set primer was applied to detect spvA and spvB genes. Also, multiplex PCR assay with two set primers was carried out to simultaneously detect and identify invA and spvC genes in S. typhimurium. Results:   Analysis of the samples showed that while the presence of spvA, spvB and spvC genes in S. typhimurium from the bovine source was 100% (15/15), these same genes were present in 65% (13/20) of the poultry sources. The study also showed that spvA, spvB and spvC genes were present in 85% of human source. Conclusion:   This study showed that M- PCR of invA, rfbJ, fljB, and fliC genes were fast, simple, less expensive, accurate and specific in identification S. typhimurium. The advantage of multiplex PCR was that it could simultaneously identify the Salmonella strains which had a virulence plasmid thus facilitating the search for specific etiologic Salmonella serovars. The higher prevalence of spv genes among bovine sources can be injurious for public health.
  • XML | PDF | downloads: 268 | views: 323 | pages: 40-48
    Background:    Ephedra sinica Stapf (Ephedraceae) is one of the most important plants in traditional medicine and medicinally important as the botanical origin of crude drugs. The main active constituents of Ephedra sinica are the unique and taxonomically restricted adrenergic agonist’s phenylpropylamino alkaloids, also known as ephedrine alkaloids: norephedrine, norpseudoephedrine, ephedrine, pseudoephedrine, methylephedrine and methylpseudoephedrine. Mthods:    In this study, ethanolic and hydroalcoholic herb extract of Ephedra sinica was assayed against on standard and clinical Pseudomonas aeruginosa bacteria activities and then the MIC and MBC were assayed. Results:    The results were shown that the lowest MIC of ethanolic herb extract of Ephedra sinica on clinical and standard Pseudomonas aeruginosa bacteria respectively was 25 and 12.5 μg/ml but the lowest MIC of the hydroalcoholic herb extract were 25 and 25 μg/ml respectively. The lowest MBC of ethanolic herb extract on clinical and standard strains of Pseudomonas aeruginosawere 50 and 25 μg/ml,  respectively. But, the lowest MBC of the hydroalcoholic herb extract against clinical and standard strains was 25 and 25 μg/ml. Conclusion:    Based on these results, suggest to antibacterial activity have to use hydroalcoholic herb extract that the toxicities of purified extracts of these plants need to study and hopefully improved traditional medicines will be developed.

Review Articles

  • XML | PDF | downloads: 182 | views: 302 | pages: 49-57
    Background:    Knowledge is an ocean without bound or shore, the seeker of knowledge is (like) the diver in those seas. Even if his life is a thousand years, he will never stop searching. This is the result of reflection in the book of development. Human beings are free and, to some extent, have the right to choose, on the other hand, they are spiritually oriented and innovative, and for this reason, the new discovery and creativity are felt. This characteristic, which is in the nature of human beings, can be a motive for the revision of life and its tools and products. It has made life, an effort to change the status quo so that it can be employing and utilizing intelligence, wisdom, deception, beauty, and choice. So, innovation, advancement, while discovering and identifying pathogenic bacteria and ways to control them, is very amazing. The era of bacterial infections can be divided into three periods; the era of the discovery, use of antibiotics and the era of the emergence of antibiotic resistance, which seems to be it is in the transition from the second to the third period. Conclusion:   So far, there are nine microbiologists that have been awarded the Nobel Prize in the field of medical Bacteriology. Therefore it is the time to identify bacterial products and their partial functions to use in a variety of areas, especially in controlling new and/or emerging infectious diseases and provide a fairly comfortable future for our next generations.