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Showing 13 results for Subject: Microbiology
Arezo Kasavandi, Maryam Bikhof Torbati, Kumarss Amini,
Volume 18, Issue 3 (10-2018)
Abstract
Background & objectives: Staphylococci are considered as one of the most important etiological agents of omphalitis. Due to the importance of early diagnosis of omphalitis in newborns, this infection can be diagnosed by novel techniques such as multiplex PCR which is rapid, cost- effective and more accurate than microbial culture. The aim of this study was to determine the frequency of Staphylococcus aureus, S. epidermidis and S.hominis species in umbilical cord infection in newborns.
Methods: In the present study, 45 umbilical cord samples were collected from Shahid Afzali pour hospital in Kerman, Iran. Followed by DNA extraction, Multiplex PCR reactions were performed using specific 16srDNA primers for S. aureus, S. epidermidis and S.hominis. Finally, PCR products were analyzed using electrophoresis and sequencing. Also, microbiological and biochemical differentiation tests were performed for the diagnosis of Staphylococci on all specimens.
Results: Amplification of 16srRNA genes for S. aureus, S. epidermidis, and S. hominis using Multiplex PCR demonstrated that the frequency of S. epidermidis ,S. aureus and S.hominis were 4.4%, 6.6% and 2.2% in the studied samples, respectively. The prevalence of staphylococcal isolates using differential tests was shown to be 33.3%.
Conclusion: This study indicated that, Multiplex PCR is a proper method for simultaneous identification of S. aureus, S. epidermidis and S.hominis species. Also, Staphylococci can be considered as a significant cause of umbilical cord infection in newborns. However, further studies urgently are needed to confirm this finding.
Ali Niapour, Keyvan Amirshahrokhi, Mohammad Azari Rad , Behnam Mohammadi-Ghalehbin B,
Volume 19, Issue 1 (4-2019)
Abstract
Background & objectives: Pentavalent antimonials are the first-line drugs for treatment of leishmaniasis, which have multiple side effects such as drug toxicity. Moreover, parasite resistance to these drugs is rising around the world. Second-line drugs, including Amphotericin B and pantamidine have also side effects and expensive for patients. According to the cytotoxic effects of paraquat, this study was conducted to evaluate the effect of paraquat on Leishmania major promastigotes and HUVECs viability.
Methods: A number of 2.5×106 of Leishmania major promastigotes were treated in each well of 96 well plates with different concentrations of paraquat. Cells were incubated for 48 hours in 24 °C. MTT test was performed for evaluating paraquat impact on promastigotes. The absorbance was measured using a microplate reader at 570 nm. The trypan blue staining assay was performed to evaluate the number of viable Leishmania major promastigotes following paraquat treatment. Furthermore, the effect of paraquat concentrations on HUVECs viability was evaluated under the cell culture condition.
Results: The results of the MTT test showed that increasing concentrations of paraquat could significantly reduce the viability and the number of Leishmania major promastigotes in comparison to control group (p<0.05). In this study, the IC50 for Leishmania major promastigotes was calculated as 272.46 µg/ml. Trypan blue results were in line with the finding of MTT assay. Moreover, we found that HUVECs were susceptible to paraquat (IC50=188.99 µg/ml).
Conclusion: Paraquat has a strong inhibitory effect on Leishmania major promastigotes and human endothelial cells. Although more comprehensive studies on the effects of the topical use of paraquat on Leishmania major lesions in animal model and its side effects are necessary.
Roghieh Saboorian, Mohammad Rahbar, Marjan Rahnamaye Farzami , Parvaneh Saffarian,
Volume 19, Issue 2 (7-2019)
Abstract
Background & objectives: Antibiotic resistance in Vibrio cholerae is a crucial matter in the world. Objective of this study was the improvement of cholera surveillance by assessing the antimicrobial resistance pattern and bacterial resistance genes in V. cholerae O1 isolates, reffered to Iranian Reference Health Laboratory, in cholera outbreaks during 2012- 2015.
Methods: This study is a cross sectional- descriptive research. Antimicrobial susceptibility test (AST) to 8 antibiotics was performed on 113 V.cholerae O1 isolates using E-test method. For all isolates, conventional PCR method was used to detect the presence of tetracycline resistance genes (tetA, tetB and tetC) and the sulfamethoxazole-trimethoprim resistance genes (sul2 and dfrA1).
Results: All isolates were sensitive to ampicillin, temocillin, ciprofloxacin and cefixime and 64% of strains showed intermediate susceptibility to erythromycin. The resistance rate of nalidixic acid, sulfamethoxazole-trimethoprim and tetracycline were 90%, 71% and 50% respectively. However, the frequency of multidrug resistant (MDR) strains varied across the years. The frequency of resistance genes (tetA, tetB, tetC, sul2 and dfrA1) were 70%, 34%, 58%, 66% and 70% respectively.
Conclusion: AST should be used to determine the resistance profile at the beginning of a cholera outbreak and to monitor the resistance profile of circulating strains as part of surveillance of the disease. A prominent association was observed between phenotypic resistance to sulfamethoxazole-trimethoprim and presence of dfrA1gene. Determining the presence of resistance genes is necessary for understanding the epidemiology and routes of transmission of antibiotic resistance genes
Zahra Ashouri Saheli, Mohammad Shenagari , Naser Harzandi , Ali Monfared,
Volume 19, Issue 2 (7-2019)
Abstract
Background & objectives: Immunosuppressive drugs that are used for decreasing risk of acute rejection and renal graft loss can lead to reactivation of latent viruses for example BKV and JCV in either renal allograft or recipients. These viruses can lead to renal graft loss. The purpose of this study was to evaluate the quality and quantity of the genome of these two viruses in the renal recipients’ plasmas for early detection.
Methods: In this retrospective descriptive study, at first, DNA extraction test was performed on 102 plasma samples of renal allograft recipients. And then, BKV and JCV DNAs were detected and quantified by Real-Time PCR.
Results: Fifty four (52.94%) BKV DNA positive and 26 (25.50%) JCV DNA positive were found in 102 recipient plasma samples. Linear range of measurements for BKV and JCV DNAs were within the range of 10 7-0.596 copies/ µl and 10 7-0.528 copies/ µl respectively. After calculation of genes amounts based on copy/ml in the plasmas, numbers and percent of positive cases were highlighted in the four categories. BKV and JCV DNA (Co-infection) were detected in 22 (21.56%) plasma samples.
Conclusion: Real-time PCR is a quantitative and qualitative PCR method that can detect genome of any type of organisms and their amounts (even in trace amounts), so using of this method is very important for early detection of viruses which can cause diseases and graft rejection in renal transplant recipients.
Sanaz Habibi, Roya Safarkar, Vahid Rouhi,
Volume 19, Issue 4 (1-2019)
Abstract
Background & objectives: Methicillin-resistant Staphylococcus aureus is one of the most common causes of nosocomial infections. The polysaccharide adhesion mechanism encoded by the ica operon generates a direct role in biofilm formation and infection of the bacteria. The aim of this study was to evaluate the frequency of icaA gene in Staphylococcus aureus isolates isolated from clinical specimens of patients admitted to some clinical centers of Rasht.
Methods: This descriptive, cross-sectional study was performed on 100 Staphylococcus aureus isolates from some clinical centers of Rasht in 2019 and confirmatory tests were performed to identify the bacteria. icaA gene identification and its frequency were investigated using molecular methods . The antibiotic resistance pattern against 10 antibiotics and biofilm-forming ability of the isolates were determined using the disk diffusion method and Congo red method respectively.
Results: In the present study, among the 100 studied isolates, the highest drug resistance was related to penicillin, and the lowest antibiotic resistance was belonged to ciprofloxacin. 81 isolates (81%) were resistant to methicillin and 37 isolates (37%) had multiple resistance. Of 37 isolates with multiple resistances, 32 isolates (86.48%) had icaA gene and 24 isolates (64.9%) ،had the ability to produce strong biofilms.
Conclusion: According to the findings of this study, the prevalence of Staphylococcus aureus isolates carrying icaA gene with strong biofilm forming ability and resistance to methicillin, were high. This necessitates the need for serious management of antibiotic administration.
Seyed Ali Bazghandi , Somayeh Safarirad, Mohsen Arzanlou, Hadi Peeri-Dogaheh , Hossein Ali-Mohammadi , Farzad Khademi,
Volume 20, Issue 2 (7-2020)
Abstract
Background & objectives: Bacterial antibiotic resistance is becoming a global health crisis. The aim of this descriptive, cross-sectional study was to investigate the prevalence of multidrug-resistant Pseudomonas aeruginosa strains in Ardabil.
Methods: During 9 months, between July 2019 and March 2020, 50 strains of Pseudomonas aeruginosa were collected from different clinical specimens in four hospitals of Ardabil and the prevalence of MDR, XDR and PDR strains of Pseudomonas aeruginosa were evaluated. Antibiotic susceptibility testing was assessed using the disk diffusion method.
Results: In the present study, the prevalence of MDR, XDR and PDR strains of Pseudomonas aeruginosa were 52%, 40% and 14%, respectively.
Conclusion: Due to high prevalence of multidrug-resistant strains of Pseudomonas aeruginosa in Ardabil, continuous monitoring of the antibiotic resistance trend in clinical isolates in order to select the best medication is necessary.
Khadijeh Hamidian, Elyas Abdollahi, Zahra Yazdanpour, Laleh Shahrakimojahed, Farzad Khademi, Hamid Vaez,
Volume 21, Issue 1 (4-2021)
Abstract
Background and objectives: Urinary tract infection (UTI) is the most prevalent infection and Escherichia coli (E. coli) is one of the main causes of UTI worldwide. Integrons are mobile genetic elements considered to be responsible for dissemination of multi-drug resistance infections. Therefore, the aims of this study were to investigate the antibiotic resistance patterns and distribution of class I, II and III integrons among E. coli isolated from patients.
Methods: In this descriptive cross-sectional study, from Jun 2020 to March 2021, in total, 70 non-duplicate strains of E. coli were isolated from patients with UTI referred to Amiralmomenin hospital, Zabol, Iran. Antibiotic resistance patterns were determined using Kirby-Bauer’s disk diffusion method and Clinical and Laboratory Standards Institute (CLSI) guidelines. Class I, II and III integrons were detected using polymerase chain reaction (PCR).
Results: The isolates showed high resistance toward ampicillin (77.1%), trimethoprim- sulfamethoxazole (58.5%) and ceftriaxone (35%), whereas were mostly susceptible to meropenem (97%). Based on results of PCR, 34 (48.6%) and 3 (4.3%) isolates were classified as class I and class II integron-positive strains, respectively.
Conclusion: Resistance rate to ampicillin, ceftriaxone and trimethoprim-sulfamethoxazole was at a high level and their prescription should be restricted. Class I integron is widely distributed among E. coli isolates and play a crucial role in the emergence of antibiotic resistance
Maryam Nazari, Hadi Ahmadi, Hamid Vaez, Farzad Khademi,
Volume 21, Issue 2 (7-2021)
Abstract
Background & objectives: Carbapenems are the main antibiotics for the treatment of infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa (P. aeruginosa). The aims of this study were to determine the prevalence of gene encoding outer membrane porin protein (OprD) in carbapenem-resistant P. aeruginosa strains as well as to assess the role of insertion sequence (IS) elements in the inactivation of OprD porin and the emergence of carbapenem resistance.
Methods: In this study, 103 clinical isolates of P. aeruginosa including 58, 42 and 23 strains resistant to imipenem, meropenem, and doripenem were used, respectively. The isolates were collected from patients referred to Ardabil hospitals. The presence of oprD gene and IS elements were investigated using polymerase chain reaction (PCR) and sequencing methods. P. aeruginosa PAO1 standard isolate was used as the positive control strain for oprD gene.
Results: The frequency of oprD gene among carbapenem-resistant P. aeruginosa strains isolated from Ardabil hospitals was 96.5%. Furthermore, IS elements were not observed in the investigated isolates.
Conclusion: Based on the results of this study, the presence of IS elements did not involve in the inactivation of outer membrane porin OprD and resistance to carbapenems among P. aeruginosa clinical strains in Ardabil. Therefore, an investigation of the role of other mutations in reducing the expression of oprD gene and increasing P. aeruginosa resistance to carbapenems is recommended.
Mohaddeseh Haji Ghasemi, Mostafa Govahi, Mojtaba Ranjbar,
Volume 22, Issue 4 (1-2023)
Abstract
Background & objectives: Due to the increasing resistance of bacteria to antibiotics and the presence of antibacterial compounds in plants, in this study, the effect of hydro-alcoholic and aqueous extracts of Physalis alkekengi on some pathogenic bacteria was investigated.
Methods: In this experimental study, the dried fruits of the Physalis alkekengi were purchased from a medicinal plant shop and after extraction, the antibacterial effect of the aqueous, ethanolic, and methanolic extracts of the plant against standard strains of Escherichia coli, Salmonella typhimurium, Bacillus subtilis, Staphylococcus aureus were evaluated. Antibacterial activity, Minimum Inhibitory Concentration (MIC), and Minimum Bactericidal Concentration (MBC) of the extracts were determined using serial dilution and disk diffusion methods.
Results: In the disk diffusion method, all concentrations of the methanolic extract of Physalis alkekengi had an inhibitory effect on Bacillus subtilis and Staphylococcus aureus. However, the inhibitory effect of the methanolic extract was considerably higher than the aqueous extract. The lowest inhibitory concentration of the methanolic extract was 12.5 mg/ml, and the minimum lethal concentration was 25 mg/ml. Aqueous and ethanolic extracts of the plant had the minimal effect on the standard strain of Staphylococcus aureus.
Conclusion: Aqueous, ethanolic, and methanolic extracts showed different levels of antibacterial properties in a concentration-dependent method. Therefore, the inhibitory effects against each bacterium can probably be attributed to the activity of the active ingredients of the plant, the extraction method, and the properties of the solvent used.
Fateme Askarifar, Ebrahim Shafaei, Mahsa Sedighi, Amir Tavakoli Kareshk,
Volume 23, Issue 3 (10-2023)
Abstract
Background: Bacterial infections are a major cause of chronic infections and mortality, and antibiotics are the preferred treatment for bacterial infections. However, studies show that widespread use of antibiotics has led to the emergence of multidrug-resistant bacterial strains. Hence, the need to develop new and alternative strategies for the production of effective drugs has become an important issue. Recently, the use of nanotechnology has been widely common in various fields. Materials in the nanoscale have unique physical and chemical properties. Silver nanoparticles have different applications and their antimicrobial properties have been confirmed in several studies. This study aimed to investigate the antibacterial properties of silver nanoparticles synthesized by berberine and Hypericum perforatum extract.
Methods: In this experimental study, the antibacterial effects of synthesized nanoparticles on standard strains of Escherichia coli [ATCC 25922], Pseudomonas aeruginosa [ATCC 27853], Klebsiella pneumoniae [ATCC 9997], and Staphylococcus aureus [ATCC 29212] were investigated. The MIC content of silver nanoparticles alone and in combination with berberine and Hypericum perforatum extract was investigated for the studied bacteria using the broth microdilution method.
Results: The results of the evaluation of the minimum inhibitory concentration [MIC] of the synthesized compounds on the studied bacteria showed that the nanoparticles synthesized by berberine and Hypericum perforatum extract had the highest antibacterial effects. However, each of the compounds Berberine and Hypericum perforatum extract alone did not show significant antibacterial properties. The results of this study also showed that the highest inhibitory concentration of nanoparticles synthesized by berberine and Hypericum perforatum extract was related to Pseudomonas aeruginosa [0.0375 mg / ml] and the lowest inhibitory concentration was related to Enterococcus faecalis [0.185 mg/ml].
Conclusions: The results of the present study showed that silver nanoparticles synthesized with berberine and Hypericum perforatum extract have significant antibacterial effects. As a result, nanoparticles, including silver nanoparticles, can become one of the most important alternatives to antibiotics due to their unique properties in targeting bacteria. However, achieving definitive results requires further studies in this area.
Elina Barazesh, Mostafa Govahi, Mojtaba Ranjbar,
Volume 24, Issue 1 (4-2024)
Abstract
Background: Ginkgo biloba is a plant with many therapeutic characteristics because it’s rich in polyphenolic contents. This study was done to evaluate the antibacterial activities of Ginkgo and to compare the antibacterial potential of ethanolic, methanolic and aqueous leaf extracts of Ginkgo biloba.
Methods: The antibacterial activity of Ginkgo extracts was evaluated using a disc diffusion method against four strains of bacteria: Escherichia coli, Salmonella typhimurium, Bacillus subtilis, and Staphylococcus aureus. The Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extracts were assessed.
Results: The results indicated that all extracts of Ginkgo possess distinguished antibacterial activity. Among them the methanolic extract exhibited maximum antibacterial activity and the aqueous extract showed minimum antibacterial activity. The highest MIC and MBC were determined at 3.13 and 6.25 µg/mL of aqueous extract against Bacillus subtilis, respectively.
Conclusion: Regarding the acquired results from this study, the leaves of Ginkgo biloba possess a considerable amount of antibacterial activity that can make them one of the most valuable antibacterial resources that could be used in food and therapeutic industries. Therefore, more studies should be conducted on this plant.
Maryam Nazari, Nilofar Saeli, Mohsen Arzanlou, Saghar Jafari-Ramedani, Hafez Mirzanejad-Asl, Farzad Khademi, Aida Alinezhad,
Volume 24, Issue 1 (4-2024)
Abstract
Background: Antibiotic resistance represents a critical global concern within the medical community, posing significant challenges in the treatment of infections caused by drug-resistant pathogens. Over the years, broad-spectrum fluoroquinolones have been extensively used to treat infections caused by both Gram-positive and Gram-negative bacteria, including Pseudomonas aeruginosa. In this study, we decided to assess the prevalence of plasmid-mediated quinolone resistance mechanisms among clinical isolates of P. aeruginosa in Ardabil hospitals.
Methods: We analyzed a total of 200 clinical isolates of P. aeruginosa, collected between June 2019 and May 2023. The antibiotic resistance profiles of these strains against various fluoroquinolone antibiotics were determined using the disk diffusion method. Additionally, we investigated the presence of qnrA, qnrB, qnrC, qnrD, and qnrS genes through polymerase chain reaction (PCR) analysis. Furthermore, we assessed the expression levels of efflux pump genes and outer membrane porin genes using the quantitative reverse transcription PCR (qRT-PCR) in fluoroquinolone-resistant P. aeruginosa strains.
Results: Our findings revealed that 69% of P. aeruginosa strains were resistant to fluoroquinolones. The resistance rates for different fluoroquinolones were as follows: ciprofloxacin 55.5%, ofloxacin 62%, norfloxacin 53.5%, lomefloxacin 55.3%, and levofloxacin 55.5%. Notably, 78.9% of these strains exhibited multidrug resistance (MDR). Among the qnr genes, qnrB was the most prevalent (2.9%). No other qnr genes were identified. Interestingly, 75% of P. aeruginosa strains carrying the qnrB gene showed overexpression of efflux pump genes, while 100% exhibited down-regulation of the oprD gene.
Conclusion: Given the high prevalence of fluoroquinolone-resistant P. aeruginosa clinical isolates in Ardabil hospitals and the multifactorial nature of resistance, continuous monitoring of antibiotic resistance trends and understanding the underlying resistance mechanisms are crucial for selecting appropriate treatment strategies.
Saghar Jafari-Ramedani, Fereshteh Hasanpour, Alireza Mohammadnia, Farzad Khademi, Aida Alinezhad,
Volume 24, Issue 3 (10-2024)
Abstract
Background: The Gram-negative pathogen Pseudomonas aeruginosa (P. aeruginosa) is a common cause of hospital-acquired infections. This bacterium is continuously increasing its resistance to commonly used antimicrobial drugs, posing significant challenges for clinical treatment. Therefore, this study aimed to investigate the trend of antibiotic resistance in P. aeruginosa from 2019 to 2023 in hospitals in Ardabil city.
Methods: This cross-sectional descriptive study utilized 200 clinical isolates of P. aeruginosa obtained from urine, respiratory, wound, blood, and cerebrospinal fluid samples of patients who visited Ardabil hospitals between June 2019 and May 2023. The sensitivity and resistance of P. aeruginosa isolates to antibiotics-including piperacillin, piperacillin / tazobactam, ceftazidime, cefepime, aztreonam, imipenem, meropenem, amikacin, tobramycin, netilmicin, ciprofloxacin, ofloxacin, norfloxacin, levofloxacin, and colistin-were assessed using the disk diffusion and agar dilution methods.
Results: Over a period of 4 years, the resistance of P. aeruginosa to various antibiotics was observed as follows: piperacillin 45.5%, piperacillin/tazobactam 31%, ceftazidime 44%, cefepime 46%, aztreonam 12%, imipenem 67.5%, meropenem 52%, amikacin 43%, tobramycin 45.5%, netilmicin 39.2%, ciprofloxacin 55.5%, ofloxacin 62%, norfloxacin 53.5%, levofloxacin 55.5%, and colistin 9%. It is worth mentioning that the trend of antibiotic resistance in P. aeruginosa to all tested antibiotics increased during the first and second years, decreased in the third year, and then experienced a significant increase again in the fourth year. Throughout this period, the emergence of multidrug-resistant (MDR) strains of P. aeruginosa has also been on the rise.
Conclusion: The present study confirmed that the overall trend of resistance to various antibiotics among P. aeruginosa strains isolated from patients in Ardabil is on the rise.
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