Microbiology
Tahereh Tahmasebi; Rahim Nosrati; Hamed Zare; Horieh Saderi; Reyhaneh Moradi; Parviz Owlia
Volume 11, Issue 4 , October 2016, , Pages 354-362
Abstract
Background: Glutathione (GSH) is a non-protein thiol compound, which plays an important role in the response to oxidative stress and nutritional stress. The aim of this study was to isolate indigenous S. cerevisiae strains capable of effectively produce GSH. Methods: One hundred-twenty sweet fruit samples ...
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Background: Glutathione (GSH) is a non-protein thiol compound, which plays an important role in the response to oxidative stress and nutritional stress. The aim of this study was to isolate indigenous S. cerevisiae strains capable of effectively produce GSH. Methods: One hundred-twenty sweet fruit samples were collected. The strains were isolated on yeast glucose chloramphenicol (YGC) agar medium and identified. The isolates were evaluated for GSH producing on yeast malt (YM) medium. Concentration of glutathione was investigated by recording absorbance of all samples at wavelength 412 nm (Ellman’s method). In addition, optimization of glucose and peptone concentration in culture medium and the effects of various environmental conditions such as temperature (20–35 °C), agitation rate (150–250 rpm), and initial pH (4.0–6.0) were assessed on producing of GSH. Results: From 120 samples, 80 isolates were identified by morphological, biochemical and molecular tests as S. cerevisiae. Five isolates were capable to produce effectively GSH. The optimal culture conditions were agitation rate, 200 rpm; temperature, 30 °C; initial pH, 6; glucose, 30 g/l; and peptone concentration, 5 g/l. In optimal conditions, the amount of derived glutathione was improved compared to YM basal medium and highest GSH concentration (296.8 mg/l) was obtained after cultivation with shaking for 72 h. Conclusion: The possibility of obtaining S. cerevisiae cells with a high GSH intracellular content can be considered an interesting opportunity of furthering the range of application and utilization of this molecule.
Microbiology
Fatemeh Rezaei; Horieh Saderi; Shahram Boroumandi; Soghrat Faghihzadeh
Volume 11, Issue 1 , January 2016, , Pages 47-53
Abstract
Background: In order to select a better antibiotic choice for treatment of Pseudomonas aeruginosa infections, this study was conducted to determine the frequency of resistance to some antipseudomonal β-lactams in P. aeruginosa isolates from patients in Tehran, Iran. In addition, the relation between ...
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Background: In order to select a better antibiotic choice for treatment of Pseudomonas aeruginosa infections, this study was conducted to determine the frequency of resistance to some antipseudomonal β-lactams in P. aeruginosa isolates from patients in Tehran, Iran. In addition, the relation between presence of genes known to be responsible for resistance to β-lactams (ampC, mexC1,2,and mexC3,4 genes) and resistance phenotype among P. aeroginosa isolates was evaluated. Methods: P. aeruginosa strains were isolated and identified by routine methods and PCR for oprL gene. Disk diffusion method was employed to determine the antimicrobial susceptibility pattern according to CLSI recommendations. PCR was used to detect the resistance genes. Results: Among 100 isolates of P. aeruginosa, 82% had ampC, 86% mexC1,2and 89% mexC3,4 genes and combinations of these genes were seen in most of isolates and only 3% of isolates had none of these genes. Resistance to mezlocillin, cefepime, ceftazidime and piperacillin/ tazobactam was seen in 46%, 41%, 36% and 29% of isolates, respectively. Significant relation (P value ≤0.05 by Chi-square or Fisher Exact test) was observed between the presence of ampC gene and resistance to all the studied β-lactams in this study. No relation was observedfor mexC genes,although many ofisolates containing these two genes were phenotypically resistant. Conclusion: This study had shown for the first time, the presence of ampC and mexC genes in significant percent of clinical isolates of P. aeruginosa in Tehran, Iran, and relation between presence of ampC gene and resistance to β-lactams.
Microbiology
Horieh Saderi; Parviz Owlia
Abstract
Background: This study was done to detect multidrug resistant (MDR) and extremely drug resistant (XDR) of Pseudomonas aeruginosa among strains isolated from patients in Tehran, Iran, due to importance of these phenotypes in treatment of human infections. Methods: Eighty eightP. aeruginosa were isolated ...
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Background: This study was done to detect multidrug resistant (MDR) and extremely drug resistant (XDR) of Pseudomonas aeruginosa among strains isolated from patients in Tehran, Iran, due to importance of these phenotypes in treatment of human infections. Methods: Eighty eightP. aeruginosa were isolated from patients in Tehran, Iran, and identified by routine methods and PCR for oprL gene. Their antimicrobial susceptibility to 16 antimicrobial agents from 7 antimicrobial categories (aminoglycosides, carbapenems, cephalosporins, fluoroquinolones, penicillins/ß-lactamase inhibitors, monobactams, polymyxins) were determined by disk diffusion method, according to recommendation of Clinical and Laboratory Standards Institute. Characterization of P. aeruginosa isolates as MDR and XDR was done according to standardized international terminology presented by European Centre for Disease Prevention and Control as well as the Centers for Disease Control and Prevention in 2011. MDR was defined as acquired non-susceptibility to at least one agent in ≥3 antimicrobial categories and XDR was defined as non-susceptibility to at least one agent in ≥6 antimicrobial categories. Results: The rates of susceptibility to antimicrobials were as follows: gentamicin 27.3%, tobramycin 54.5%, amikacin 56.8%, netilmicin 36.4%, imipenem 55.7%, meropenem 55.7%, doripenem 60.2%, ceftazidime 63.6%, cefepime 56.8%, ciprofloxacin 59.1%, levofloxacin 60.2%, ticarcillin-clavulanic acid 37.5%, piperacillin-tazobactam 63.6%, aztreonam 43.2%, colistin 90.9%, polymyxin 95.5%. Altogether, 48 (54.5%) and 29 (33%) isolates were characterized as MDR and XDR, respectively. Discussion:The high frequency of antibiotic resistance in clinical isolates of P. aeruginosa in Iran makes epidemiological surveillance of susceptibility of this bacterium more essential for the best selection of empirical antibiotics.
Mohammad Ibrahim Yarmohammadi; Horieh Saderi; Pupak Ezadi; Siamak Afshin Majad; Maryam Hashemi
Volume 5, Issue 2 , March 2010, , Pages 72-76
Abstract
Background and Objectives: Nasal polyposis is a diseases resulting from complex pathogenetic mechanisms. Some studies showed that TGFβ1 had significant role in this pathogenesis. In this study, we investigated the roe of cytokines and mediators in polyp development. Material and Methods: ...
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Background and Objectives: Nasal polyposis is a diseases resulting from complex pathogenetic mechanisms. Some studies showed that TGFβ1 had significant role in this pathogenesis. In this study, we investigated the roe of cytokines and mediators in polyp development. Material and Methods: In this case- control study, healthy nasal mucosal samples were obtained from 24 people undergoing septoplasty or rhinoplasty and polyp samples were obtained from 15 patients with nasal and paranasal sinuses polyposis undergoing endoscopic sinus surgery. TGFβ1 concentration was measured with ELISA in homogenized polyp and control samples. The difference of the mean concentrations was analyzed with Mann-Whitney test. Results: We detected TGFβ1 in 11 patients’ samples and in 22 control samples. There was not significant differentiation between the mean of TGFβ1 levels in two groups. Conclusion: Measuring level of TGFβ1 with ELISA technique in homogenized polyp and control samples have not significant differentiation.
Mohammad Ebrahim Yarmohammadi; Horieh Saderi; Tahere Shahrokhtabar
Volume 5, Issue 1 , January 2010, , Pages 14-17
Abstract
Background and Objective: Sinusitis is one of the most common hygienic problems and a large part of the budget has been allocated to its diagnosis and treatment yearly. In this study, the presence of cytomegalovirus in sinuses of patients, undergone operation for treatment, with or without sinusitis, ...
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Background and Objective: Sinusitis is one of the most common hygienic problems and a large part of the budget has been allocated to its diagnosis and treatment yearly. In this study, the presence of cytomegalovirus in sinuses of patients, undergone operation for treatment, with or without sinusitis, was studied. Materials and Methods: This study was an applied and case-control study, which had been performed on 44 HIV negative patients in ENT clinic of Shahid Mostafa Khomeini Hospital in Tehran during 4 months in 2005.Biopsy specimens were taken from left and right of uncinet process mucosa of middle meatus of 22 patients with chronic sinusitis and 22 patients without sinusitis undergo operation for nasal septal deviation. After purification of DNA, PCR test was done for replication of early gene in cytomegalovirus DNA by two kits, which was purchased from Cinnagen Co. and Gen Fanavaran Co. Results: After the electrophoresis of PCR product on agarose gel, neither of samples has shown DNA band same the positive control enclosed in kits. Therefore, all specimens were considered negative for cytomegalovirus DNA. Conclusion: Cytomegalovirus has not been detected in sinunasal mucosa of patients with chronic sinusitis and without sinusitis. Test with more specimens and other diagnostic procedure are recommended for prove of absence of cytomegalovirus in sinunasal mucosa.
Horieh Saderi; Parviz Owlia; Maryam Eslami
Volume 4, Issue 4 , September 2009, , Pages 161-166
Abstract
Background and Objectives: Staphylococcus aureus is an important cause of nosocomial and community-acquired infections in every region of the world. Clindamycin is one of the alternative agents used to treat S. aureus infections and accurate identification of clindamycin resistance is important to prevent ...
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Background and Objectives: Staphylococcus aureus is an important cause of nosocomial and community-acquired infections in every region of the world. Clindamycin is one of the alternative agents used to treat S. aureus infections and accurate identification of clindamycin resistance is important to prevent therapeutic failure. Unfortunately, inducible clindamycin resistance is not detected by standard susceptibility tests. This study aimed to determine the prevalence of the macrolides-lincosamides-streptogramins B (MLSB) resistance in S. aureus isolated in four university hospitals in Tehran, Iran. Material & Methods: Two hundreds and forty-four non-duplicate clinical isolates of S. aureus (133 methicillin resistant S. aureus (MRSA) and 111 methicillin susceptible (MSSA) S. aureus) were collected in 2008. Antimicrobial susceptibilities were determined by the D-test. Results: Altogether, 68% and 61.1% of isolates were resistant to erythromycin and clindamycin, respectively; with higher resistance in MRSA isolates compared to MSSA isolates. The constitutive MLSB (cMLSB) resistance phenotype was recognized in 61.1%, while 5.3% had shown inducible MLSB (iMLSB) resistance phenotype. Constitutive MLSB resistance phenotype predominated over inducible MLSB resistance phenotype and susceptible phenotype (83.9, 9.3 and 6.8%, respectively) among the MRSA isolates, whereas susceptible phenotype predominated over constitutive MLSB resistance phenotype and inducible MLSB resistance phenotype (62.6, 31.3 and 2%, respectively) among the MSSA isolates. Conclusion:Considering the higher prevalence of clindamycin resistance in MRSA isolates compared MSSA isolates, routine D-test of MRSA isolates is strongly recommended to prevent treatment failure.
Horieh Saderi; Parviz Owlia; Zohreh Maleki; Mehri Habibi; Nayere Rahmati
Volume 3, Issue 3 , June 2008, , Pages 161-167
Abstract
Background and Objective: Vancomycin is frequently the antibiotic of choice for the treatment of infections caused by methicillin-resistant Staphylococcus aureus (MRSA). For the last years, the incidence of vancomycin-intermediate S. aureus (VISA) and vancomycin-resistant S. aureus (VRSA) has ...
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Background and Objective: Vancomycin is frequently the antibiotic of choice for the treatment of infections caused by methicillin-resistant Staphylococcus aureus (MRSA). For the last years, the incidence of vancomycin-intermediate S. aureus (VISA) and vancomycin-resistant S. aureus (VRSA) has been increased in various parts of the world. The present study was carried out to determine the presence of VISA and VRSA in Tehran. Materials and Methods: A total of 164 S. aureus strains were isolated from clinical specimens in four university-affiliated hospitals in Tehran from November 2006 to June 2007. Minimum inhibitory concentration (MIC) of vancomycin of isolates was determined by agar dilution method. Vancomycin (6 mg/l) screen agar plate method and E-test were used to confirm presence of resistance to vancomycin. Disc diffusion agar test was also used to detect resistance to other antimicrobial agents. Results: Only one VRSA(MIC 256 mg/l) was detected and three strains with MIC 4 mg/l considered VISA according to recent CLSI breakpoints for vancomycin. Only VRSA strain had shown growth on vancomycin screen agar plate and was also resistant to several antimicrobial agents but susceptible to quinupristin/dalfopristin, linezolid, chloramphenicol, mupirocin and cotrimoxazole. Isolated VISA were also multi-resistant but showed susceptibility to quinupristin/dalfopristin, linezolid, chloramphenicol and mupirocin. Conclusion: Detection of vancomycin resistance in Iranian S. aureus isolates emphasizes the challenges confronted by the infection control specialists in hospitals in Iran as well as causing problems in the treatment of patients with S. aureus infections.
Horieh Saderi; Mehri Habibi; Parviz Owlia; Mohammadreza Asadi Karam
Volume 3, Issue 1 , January 2008, , Pages 11-14
Abstract
Background and Objective: Methicillin resistance in Staphylococcus aureus is an increasingly important clinical problem. A chromosomal gene, mecA, mediates resistance to penicillinase-resistant penicillins such as methicillin and oxacillin in Staphylococcus aureus. We evaluated the validity of ...
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Background and Objective: Methicillin resistance in Staphylococcus aureus is an increasingly important clinical problem. A chromosomal gene, mecA, mediates resistance to penicillinase-resistant penicillins such as methicillin and oxacillin in Staphylococcus aureus. We evaluated the validity of disk diffusion test by using oxacillin, methicillin and cefoxitin disks with consideration of the presence of mecA gene as the reference method for detection of methicillin resistant Staphylococcus aureus (MRSA). Materials and Methods: The susceptibility testing of 222 S. aureus clinical isolates to oxacillin (1 µg), cefoxitin (30 µg) and methicillin (5 µg) was carried out by the disk diffusion method according to the Clinical Laboratory Standards Institute guidelines. Detection of mecA gene was performed using PCR method. Results: An amplified mecA gene of 310 bp was detected in 55% of examined strains by PCR, thus 55% strains were considered MRSA. Sensitivity of oxacillin, methicillin and cefoxitin disks were determined 100%, 99.1% and 98.3% respectively. All MRSA strains in PCR had shown resistance to penicillinase-resistant penicillins by oxacillin disk, but two and one strains were sensitive by cefoxitin and methicillin disk respectively. Thus, oxacillin was the most appropriate disk for detecting MRSA. Conclusion: The prevalence of MRSA in this study is comparable to that found in United States, Canada, Europe and Iran, but the percentage of MRSA isolates is almost twice of percentage reported from Japan.
Parviz Owlia; Horieh Saderi; Zohreh Karimi; Seyed Mohammad Bagher Akhavi Rad; Mohammad Ali Bahar
Volume 3, Issue 1 , January 2008, , Pages 20-25
Abstract
Background and Objective: Metallo-beta-lactamase (MBL)-mediated resistance is an emerging threat in hospital isolates of Pseudomonas aeruginosa. There is not enough information from Iran regarding the prevalence and the screening methods for such enzymes. The present study was undertaken to detect ...
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Background and Objective: Metallo-beta-lactamase (MBL)-mediated resistance is an emerging threat in hospital isolates of Pseudomonas aeruginosa. There is not enough information from Iran regarding the prevalence and the screening methods for such enzymes. The present study was undertaken to detect Metallo betalactamase in strains of P. aeruginosa isolated from burned patientusingphenotypic method. Materials and Methods: For this purpose, 128 consecutive P. aeruginosa isolates obtained from hospitalized patients were subjected to susceptibility testing to antipseudomonal drugs by disc diffusion and minimal inhibitory concentration (MIC) for ceftazidime was determined. The production of MBL was detected by the zone size enhancement with EDTA impregnated ceftazidime disc. Results: It was found out that 94 (73.44%) of the isolates were resistant to ceftazidime. These isolates screened as ESBLs producing strains and introduced for detection of MBL production. Out of the 94 P. aeruginosa that were resistant to ceftazidime, 50 (53.2%) isolates were MBL positive. This result indicated that 39.06% of all isolates were MBL positive. Conclusion: MBL-mediated ceftazidime resistance in P. aeruginosa is a cause for concern in the therapy of critically ill patients. The MBL producing P. aeruginosa isolates were more resistant to various antimicrobial agents. This result suggests that MBL producing isolates in hospitals may cause serious infections that illustrated when these strains were responsible for a nosocomial outbreak.
Horieh Saderi; Parviz Owlia; Mohammad Reza Jalali Nadoushan; Farid Zaeri; Elaheh Zandieh
Volume 1, Issue 3 , June 2006, , Pages 99-104
Abstract
Background and Objectives: This study was designed as a retrospective study on urine samples during three years in Shaheed Mostafa Khomeini Hospital to determine demographic characteristics of patients with urinary tract infection (UTI), microbial etiology, and susceptibility of isolated bacteria to ...
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Background and Objectives: This study was designed as a retrospective study on urine samples during three years in Shaheed Mostafa Khomeini Hospital to determine demographic characteristics of patients with urinary tract infection (UTI), microbial etiology, and susceptibility of isolated bacteria to antibiotics. Materials and Methods: All urines fulfilling the criteria for significant bacteriuria (>104 colonyforming units/ml of urine) were included in the study. Isolation and identification of bacteria was performed by standard method and susceptibility testing was determined by disk diffusion method according to NCCLS guideline. A total of 909 patients with urinary tract infection were enrolled in this study. Results: Mean age of the patients was 53.2 years. In addition, females were affected more often than males (female/male sex ratio was 2.22). Meanwhile, considering all strains, 79.5% were Gram-negative bacilli and 67.7% were Enterobacteriaceae. Furthermore, E.coli and Klebsiella spp represented the most common Gram-negative and Enterococci and S. aureus represented the most frequent Gram-positive isolates. The four most frequently isolated bacteria were E. coli (52.1%), Enterococci (10.5%), klebsiella spp. (10.3%), and pseudomonas spp. (9.4%). In addition, E. coli was significantly more common in females (56.6%) than in males (42.2%) and in outpatients (57.4%) than in inpatients (47.4%). The proportion of pseudomonas spp. was significantly higher in males (17.7%) than in females (5.6%). Enterococci were significantly more common in inpatients (12.5%) than in outpatients (8.4%). Altogether, the rate of susceptibility of all UTI pathogens was very low to ampicillin (6.9%) and high to cefotaxime (83.6%) and ciprofloxacin (78.2%). Urinary pathogens isolated from female patients and outpatients were more susceptible to most of examined antibiotics than those isolated from males and inpatients. Conclusion: It was found out that degrees for antibiotic resistance of urinary pathogens are alarming and show the necessity of keeping up the monitoring of antibiotics susceptibility in UTI isolates and restricting antibiotic consumption in our population.
Parviz Owlia; Horieh Saderi; Sadegh Mansouri; Sirus Salemi; Hossein Ameli
Volume 1, Issue 2 , April 2006, , Pages 61-64
Abstract
Background and Objectives: Infection is the most common problem following burn injury. Selection and dissemination of intrinsic and acquired resistance mechanisms increase the probability of burn wound colonization by resistant species including Pseudomonas aeruginosa. Multi-drug resistant Pseudomonas ...
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Background and Objectives: Infection is the most common problem following burn injury. Selection and dissemination of intrinsic and acquired resistance mechanisms increase the probability of burn wound colonization by resistant species including Pseudomonas aeruginosa. Multi-drug resistant Pseudomonas aeruginosa has frequently been reported as the cause of nosocomial outbreaks of infection in burn wards or as colonizers of the wound of burned patients. Therefore, this research study was conducted to compare the activity of various antibiotics and disinfectants against clinically important strains of P. aeruginosa. Materials and Methods: One hundred strains of P. aeruginosa were obtained as clinical isolates from burn wound infections. The antimicrobial activity of antibiotics was tested by disk diffusion method of Kirby-Baur. For disinfectants, 30 μl of each of them was placed on sterile blank disk and studied by disk diffusion method. Results: The frequency of resistant strains to kanamycin, tobramycin, amikacin, cefotaxime, carbenicillin, ceftazidime, ceftizoxime, cefixim, ciprofloxacin, cefazolin, cephalexine, and ceftriaxone was 100, 93, 95, 81, 84, 95, 94, 100, 99, 100, 100, and 92 respectively. The averaged diameter of inhibition zone for chlorhexidine (0.2%), povidione iodine (10%), cetrimide-C (3.5%), dekosept, hypochlorite (10%), micro 10+ (2%), deconex 53+ (2%), and ethanol (70%) was 14.4 ± 1.9 mm, 10.6 ± 1.3 mm, 9.1 ± 2.6 mm, 8.6 ± 2.2 mm, 26.9 ± 5.2 mm, 6.58 ± 1.5 mm, 8.3 ± 2.2 mm, and 6 ± 0.0 mm respectively.
Mohammad Ebrahim Yarmohammadi; Horieh Saderi; S.Hadi Saghelaini; Jamshid Narenjkar J
Volume 1, Issue 1 , January 2006, , Pages 31-34
Abstract
Objective: To investigate the presence of Helicobacter pylori in sinonasal mucosa of patients with chronic sinusitis Design: A prospective case-control study Materials and methods: Mucosal specimens were collected from the mid-third middle meatus and lateral side of mid-cornea. H. pylori has been investigated ...
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Objective: To investigate the presence of Helicobacter pylori in sinonasal mucosa of patients with chronic sinusitis Design: A prospective case-control study Materials and methods: Mucosal specimens were collected from the mid-third middle meatus and lateral side of mid-cornea. H. pylori has been investigated using PCR after DNA extraction and urease test. Results: H. pylori was not found in any of the sample taken from both groups (case and control patients). Conclusion: This is the first reported study to investigate the presence of H. pylori in sinonasal mucosa in Iran. In this study, H. pylori was not determined in these sites, although its possible presence could not be excluded. Thus, further investigation on more patients and application of sensitive diagnostic techniques are recommended.
