Vol 4 No 3-4 (2015)

Original Articles

  • XML | PDF | downloads: 293 | views: 379 | pages: 1-7
    Background:  AmpC beta lactamases play a significant role in creating resistance to third generation cephalosporins worldwide. They mostly express on chromosome of Enterobacteriaceae especially Escherichia coli and cause consequential problem in clinical treatment and lead to failure in diagnosis and phenotypic test recommended by Clinical and Laboratory Standards Institute. Methods: Totally 200 E. coli isolates from different hospitals of Tehran were collected. The isolates were screened by disk diffusion method according to the CLSI guidelines. The profiles and prevalence surveys of AmpC (Dha, CITM, Mox and FOX-type) β-lactamase genes in clinical isolates of E. coli by phenotypic and molecular methods. Results:   Out of 200 E. coli isolated, 115 (89.8%) and 13 (10.2%) isolates were identified as ESBL- and AmpC- beta-lactamase producers, respectively. Among AmpC producers, 13 (100%) and 5 (38.5%) isolates was reported by PCR assay as blaCITM and Dha, respectively. Mox and FOX genes were not detected in any sample.Conclusion:   Our results highlight the importance of using molecular detection methods to identify β-lactamase-producer that have resistance to antibiotics.
  • XML | PDF | downloads: 294 | views: 362 | pages: 8-14
    Background:    Unfortunately, antibiotic resistance has become an increasingly critical problem in many countries like Iran. Since there are very few published data on antibiotics resistance in Alborz province, the aim of this study was to survey the pattern of antimicrobial resistance and prevalence detection of TEM-type beta-lactamases among clinical isolates of Escherichia coli using universal primers. Methods:    The study was performed on 83 clinical Escherichia coli strains collected from hospitals and clinical laboratories. Antimicrobial susceptibility was performed using Kirby-Bauer disk diffusion method against common antibiotics. Isolates were also screened for the production of extended spectrum beta-lactamases (ESBLs) by double disk synergy test (DDST). Positive isolates were evaluated by PCR analysis for the TEM family of ESBLs genes. Results:   Isolates showed the highest resistance to amoxicillin (83%), whereas nitrofurantoin was the most effective drug, with only 8.4% resistance. The frequency of multi drug resistance (MDR) to more than 5 antibiotics was 79.5% (66 strains). ESBL screening of E. coli strains by DDST showed that out of 83 strains, 33 isolates were ESBL positive. Based on the PCR results 61 percent of phenotypic ESBL positive E. coli isolates possessed a single gene encoding a TEM type ESBL.Conclusion:   As the results of this study indicate, multidrug resistance is an increasing therapeutic concern and treatment requires further attention to the results of susceptibility tests. As antibiotic options in the treatment of ESBL-producing organisms are extremely limited, molecular screening by laboratories is suggested to reduce the risk of therapeutic defeat.
  • XML | PDF | downloads: 407 | views: 408 | pages: 15-23
    Background:   Pseudomonas aeruginosa is a severe challenge for antimicrobial therapy, because of chromosomal mutations or exhibition of intrinsic resistance to various antimicrobial agents such as most β-lactams. We undertook this study to evaluate the existence of SME, AIM and VIM metallo-beta lactamases encoding genes among P. aeruginosa strains isolated from ICU patients in AL-Zahra Hospital in Isfahan, Iran. Methods:  In a retrospective cross sectional study that was conducted between March 2012 to April 2013, in total 48 strains of P. aeruginosa were collected from clinical specimens of bedridden patients in ICU wards. Susceptibility test was performed by disc diffusion method. All of the meropenem resistant strains were subjected to modified Hodge test (MHT) for detection of carbapenemases. Multiplex PCR was performed for detection of VIM, blaAIM, blaSME genes. Results:   In disk diffusion method imipenem and meropenem showed the most and colistin the least resistant antimicrobial agents against P. aeruginosa strains. Of the 48 isolates 36, (75%) were multidrug resistant. Amplification of β-lactamase genes showed the presence of blaVIM genes in 7 (%14.6) strains. All of the isolates were negative for blaSME and blaAIM genes. We couldn’t find any statistically significance difference among presence of this gene and MDR positive, age or source of the specimen. Conclusion:   As patients with infections caused by MBL-producing bacteria are at an intensified risk of treatment failure, fast determination of these organisms is necessary. Our findings may provide useful insights in replace of the appropriate antibiotics and may also prevent MBLs mediated resistance problem.
  • XML | PDF | downloads: 280 | views: 345 | pages: 24-29
    Background:  Science the discovery of antibiotic, the incidence of antibiotic resistance has been inevitable. Although there has been many study in these area but problem still exists. The aim of this research was to study the serotyping and multiple antibiotic resistance patterns of Shigella sonnei isolated from diarrheal stool of children. Methods:  The stool samples of children from zero to fourteen years of age admitted at Children Medical Center in Tehran were tested over period of twelvemonth. Identification of isolates was carried out according to standard methods and the antibiotic susceptibility test was performed using Kirby Bauer disk method. Results:   Of the 200 samples analyzed 6 (3%) were tested positive for Shigella sonnei. The antibiotic resistance patterns showed that all were résistance to tetracycline, streptomycin, clindamycin and cortimoxazol, and 66.7% of the samples had multiples resistance to above antibiotics. Conclusion:  The results showed that multiple antibiotics resistance of Shigella sonnei is increasing, therefore awareness about the prevention by improved hygiene and proper medication are needed to reduce the burden of the preventable infectious diseases among young children.
  • XML | PDF | downloads: 251 | views: 275 | pages: 30-34
    Background:  Vibrio species including V. cholera, V. mimicus, V. parahaemolyticus, and V. vulnificus may cause gastrointestinal diseases after seafood consumption, and wound infections in swimmers and fishermen after exposing to seawater. This study determined the prevalence of the four Vibrio species in Tonkabon and Ramsar recreational beach water (approximately 200 meter far from the place where the river reaches the sea) and estuaria (place where the river reaches the sea) in northern part of Iran from autumn 1391 through autumn 1392. Methods:  Three hundreds water samples were collected for the detection of Vibrio species, using biochemical identification. Results:   Genomic DNA extracted from isolates and 16Sr DNA PCR confirmed the successful isolation of 9 Vibrio species in recreational beach water region. Conclusion:  Out of 300 samples, nine positive samples include one V. cholerae and eight V. parahaemolyticus were found at recreational beach (approximately 200 meter far from the place where the river reaches the sea).
  • XML | PDF | downloads: 235 | views: 248 | pages: 35-44
    Background:  Pathogenic bacteria because of beta-lactam antibiotic resistance genes are dangerous to society. This resistance due to ESBL genes, plasmids and transposons that by receiving or mutation occurs. The most important factor beta-lactam antibiotic resistance is beta lactamase enzymes. The purpose of this study was to evaluate the frequency of hospital opportunistic pathogenic bacteria producing ESBL and CTX-M genes identified are molecular methods. Methods:  In this study, 500 isolates from patients in the ICU of hospitals in the city of Qom was diagnosed by standard biochemical tests. Combined disk test for isolated resistant strains of ESBL was performed in order to identify. Then, strains producing ESBL, DNA extraction and CTX-M genes were detected by PCR. Results:   A total of 500 strains isolated, 20 strains (51.28%) of P. aeruginosa strains, 40 strains (62.5%) of E. coli strains, 38 strains (48.1%) of K. pneumoniae strains, 8 strains (33.33%) A. baumannii bacteria strains and 4 strains (23.52%) of the strains of Enterobacter were carrying CTX-M genes. Conclusion:  This study represents a high percentage of beta-lactamase resistance among hospital opportunistic pathogens bacteria. Due to the high prevalence of antibiotic resistance carried out detailed antibiogram tests in infections caused by ESBL-producing organisms is necessary.
  • XML | PDF | downloads: 396 | views: 626 | pages: 45-55
    Background:  Kefir contains lactic acid bacteria (Lactobacillus, Lactococcus, Leuconostoc, Acetobacter and Streptococcus) and yeasts (Kluyveromyces, Torula, Candida, and Saccharomyces). Kefiran is the polysaccharide produced by lactic acid bacteria in kefir. Methods:  Kefiran was prepared from milk containing 0.5% fat and 10 grams kefir grains and was separated from kefir by ethanol (0.02 gram) following entrapping the platelets to this polymer. Ligand of the platelet-polysaccharide was studied by FTIR. Results:  FTIR results showed that the bands of C-O and C-O-C connections were formed and the polysaccharides had been attached to the receptors of the platelet glycoproteins (GP Ib, GPIIb / IIIa). Stability and encapsulation of the platelet and kefiran were assessed by Coulter Counter. Encapsulation of the platelets by polysaccharide at the beginning caused to reduce the number of platelets following by releasing of 50% of the platelets after 3 hours. Conclusion:   The platelets were encapsulated in kefiran polymer and detected for bioavailability as new drug for surface bleeding. Also, kefiran has antimicrobial and antifungal properties. On the other hand, the existence of nisin in kefiran could be useful as an antibacterial lantibiotic.

Short Communications

  • XML | PDF | downloads: 218 | views: 245 | pages: 56-60
    Background:   Acinetobacter baumannii has become one of the most important causes of nosocomial infections in recent years. The organism seems to be resistant to most classes of antibiotics. Carbapenems are considered the most effective drugs for treatment of these infections. However, increasing emergence of carbapenem resistant A. baumannii has become a major healthcare problem. Methods:  The present study was conducted to compare the antibiotic susceptibility of 61 isolates of A. baumannii (31 from patients with burn infections and 30 from non-burn patients) to 12 antibiotics including imipenem and meropenem by disc diffusion. Results:   Both groups of the isolates showed high levels of resistance to all classes of antibiotics except for aminoglycosides. Imipenem resistance was observed in 96.7% of the non-burn isolates and 100% among the burn strains. Conclusion:   On the other hand, resistance to meropenem was significantly higher in non-burn isolates (83.3%) compared to the burn strains (6.4%).