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Papers by Abdollah Ardebili

Acta microbiologica et immunologica Hungarica (Print), May 8, 2021

Carbapenems are employed to treat infections caused by Gram-negative bacteria including Klebsiell... more Carbapenems are employed to treat infections caused by Gram-negative bacteria including Klebsiella pneumoniae. This research is aimed to perform phenotypic detection of b-lactamases and molecular characterization of NDM-1 positive K. pneumoniae isolates. Another objective is to investigate NDM-1 producing K. pneumoniae among children in Iran. From 2019 to 2020, altogether 60 K. pneumoniae isolates were acquired from various patients in certain Iranian hospitals. Antimicrobial susceptibility testing was performed by disk diffusion and broth microdilution methods. In addition, mCIM and eCIM were used to confirm the production of carbapenemases and metallo-beta-lactamases (MBLs), respectively. Detection of resistance genes namely, bla NDM-1 , bla IMP , bla VIM , bla KPC , bla OXA-48-like , bla CTX-M , bla SHV , bla TEM , and mcr-1 was performed by PCR and confirmed by DNA sequencing. Multilocus sequence typing (MLST) was employed to determine the molecular typing of the strains. According to the findings, the highest rate of carbapenem resistance was detected against doripenem 83.3% (50). Moreover, 31.7% (19) were resistant to colistin. Further to the above, altogether 80% (48) were carbapenemase-producing isolates and among them 46.7% (28) of the isolates were MBL and 33.3% (20) isolates were serine b-lactamase producer. According to the PCR results, 14 isolates produced bla NDM-1. Remarkably, four bla NDM-1 positive isolates were detected in children. In addition, these isolates were clonally related as determined by MLST (ST147, ST15). Altogether ten bla NDM-1 positive isolates were ST147 and four bla NDM-1 positive isolates were ST15. Based on the results, the emergence of NDM-producing K. pneumoniae among children is worrying and hence, it is necessary to develop a comprehensive program to control antibiotic resistance in the country.

Jundishapur Journal of Microbiology, Nov 21, 2018

Background: The ability of extended spectrum beta-lactamases (ESBLs) production is one of the mai... more Background: The ability of extended spectrum beta-lactamases (ESBLs) production is one of the main mechanisms for the emergence of antibiotic resistance in Escherichia coli and Klebsiella pneumoniae. Objectives: The aim of this study was to evaluate the occurrence of IS903, IS26, and ISEcp1 insertion elements among the CTX-Mproducing K. pneumoniae and E. coli isolates from patients with leukemia in Tehran. Methods: Eighty E. coli and K. pneumoniae isolates were recovered from patients admitted to hospitals of Tehran. Antibiotic susceptibility tests were performed by Kirby-Bauer disc diffusion and broth microdilution methods. Detection of ESBL producers was evaluated by phenotypic confirmatory test. The presence of IS903, IS26, and ISEcp1 insertion elements in CTX-M-positive E. coli and K. pneumoniae isolates was investigated by PCR-sequencing methods. Results: The rate of resistance of 80 E. coli and K. pneumoniae isolates against the nine antibiotics was as follows: 100% to ampicillin, 15% to amikacin, 51% to ciprofloxacin, 30% to gentamicin, 58% to ceftriaxone, 10% to imipenem, 63% to cefotaxime, 51% to levofloxacin, and 55% to ceftazidime. Using phenotypic confirmatory test revealed that 51 (63.75%) isolates were ESBL producers. The prevalence of CTX-M-1, CTX-M-2, CTX-M-9, CTX-M-8, and CTX-M-25 genes was 87.5%, 13.75%, 23.75%, 10%, and 0%, respectively. IS903, IS26, and ISEcp1 elements were detected in 93.75%, 71.25%, and 100% of the isolates, respectively. Conclusions: This study indicates that the high prevalence of antibiotic resistance, IS and CTX-M-producing E. coli, and K. pneumoniae isolates could be a major concern and highlights the need for infection control measures.

Oman Medical Journal, Nov 1, 2016

ethicillin-resistant Staphylococcus aureus (mrSa) is an important nosocomial pathogen infecting d... more ethicillin-resistant Staphylococcus aureus (mrSa) is an important nosocomial pathogen infecting defenseless individuals in hospitals throughout the world. 1-3 There are growing numbers of studies implying the etiologic role of coagulasenegative Staphylococci (ConS) in disease in immunocompromised patients, and the increased prevalence of multidrug-resistant strains. 4-6 These species have the ability to survive in medical facilities for months. 7 The emergence and rise of antibiotic resistance among Staphylococci is a burden in health care facilities and communities. 8 biocides (antiseptics, disinfectants, and preservatives) are chemical compounds applied to inactivate or destroy microorganisms in various settings (e.g., the health care sector, agriculture and the food industry). 9-11 by the mid-1900s, many biocidal compounds were in common use as industrial preservatives and in the medical field. 10,11 Today, biocides have become an integral part of the industrialized world and are invaluable compounds in the control of human and animal pathogens. 12 large amounts of biocides are therefore consumed within the different settings, including the medical environment where they are used for disinfection, antisepsis, and cleaning. 9 a wide variety of biocidal agents, including quaternary ammonium compounds (QaCs), such as benzalkonium chloride (baC) and benzethonium chloride (bZT) and divalent cations like chlorhexidine digluconate (CHdG) original article

International Journal of Molecular and Clinical Microbiology, Jun 1, 2013

Aquatics are a source of bioactive compounds that these compounds have different properties such ... more Aquatics are a source of bioactive compounds that these compounds have different properties such as antimicrobial activity. In this study, antibacterial activity of methanol, chloroform and hexane extracts from body wall, gonad and intestine of sea cucumber Holothuria leucospilota was evaluated against Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus. Bioactive compounds of body wall, gonad and intestine of the sea cucumber Holothuria leucospilota collected from the north coast of the Persian Gulf were extracted using methanol, chloroform and hexane. The antibacterial activity was determined using the serial dilution method. The minimum inhibitory concentration and minimum bactericidal concentration was evaluated by broth micro dilution method. Results demonstrated that the P.aeruginosa was shown to be the most sensitive microorganism. All concentrations of methanol extracts from body wall, gonad and intestine did not show antibacterial activity against B.subtilis and S.aureus. Methanol extracts of gonad and intestine and chloroform extract from body wall showed no antibacterial activity against P. aeruginosa. Hexane extract from gonad had no inhibitory effect on the growth of B. subtilis in any of the concentrations. Other extracts had antibacterial effect in certain concentrations studied. None of the extracts showed any bactericidal effect against B. subtilis. Based on findings of this study, sea cucumber extracts can be considered as a natural antibiotic in the future research.

Indian Journal of Medical Research, 2018

: Overexpression of efflux pumps is a cause of acquired resistance to fluoroquinolones in Acineto... more : Overexpression of efflux pumps is a cause of acquired resistance to fluoroquinolones in Acinetobacter baumannii. The present study was done to investigate the presence and overexpression of AdeABC efflux system and to analyze the sequences of AdeR-AdeS regulatory system in ciprofloxacin-resistant A. baumannii isolates. : Susceptibility of 50 clinical A. baumannii isolates to ciprofloxacin, imipenem, ceftazidime, cefepime and gentamicin antimicrobials was evaluated by agar dilution method. Isolates were screened for the evidence of active efflux pump. Isolates were also examined for adeR-adeS and adeB efflux genes by polymerase chain reaction (PCR). The adeR and adeS regulatory genes were sequenced to detect amino acid substitutions. Expression of adeB was evaluated by quantitative reverse-transcriptase PCR. : There were high rates of resistance to ciprofloxacin (88%), ceftazidime (88%), cefepime (74%) and imipenem (72%) and less resistance rate to gentamicin (64%). Phenotypic assay showed involvement of active efflux in decreased susceptibility to ciprofloxacin among 16 isolates. The 12.27-fold increase and 4.25-fold increase were found in adeB expression in ciprofloxacin-full-resistant and ciprofloxacin-intermediate-resistant isolates, respectively. Several effective mutations, including A91V, A136V, L192R, A94V, G103D and G186V, were detected in some domains of AdeR-AdeS regulators in the overexpressed ciprofloxacin-resistant isolates. The results of this study indicated that overexpression of the AdeABC efflux pump was important to reduce susceptibility to ciprofloxacin and cefepime in A. baumannii that, in turn, could be triggered by alterations in the AdeR-AdeS two-component system. However, gene expression alone does not seem adequate to explain multidrug resistance phenomenon. These results could help plan improved active efflux pump inhibitors.

Expert Review of Anti-infective Therapy

Social Science Research Network, 2023

Medical Laboratory Journal

Background and objectives: Aflatoxin B1 (AFB1) is the most toxic aflatoxin produced by a large nu... more Background and objectives: Aflatoxin B1 (AFB1) is the most toxic aflatoxin produced by a large number of Aspergillus species. Successful detoxification of this toxin is an important attempt to improve community health. The aim of this study was to evaluate reducing effects of yeasts isolates from kefir and traditional kefir-like fermented beverages on AFB1 in a broth medium. Methods: Polymerase chain reaction-sequencing was carried out to identify the yeast isolates from kefir and kefir-like beverages. Effects of the isolates on AFB1 adsorption and biotransformation in peptone dexterose broth medium were evaluated by using high performance liquid chromatography. Results: Saccharomyces cerevisiae and Kluyveromyces marxianus were isolated from kefir and kefir-like beverages and resulted in 46% and 53% AFB1 adsorption, respectively. The isolates 27Y and 2Y caused 7% toxin biotransformation, while 10% toxin biotransformation was achieved by the isolate 18Y. Conclusion: Our results indicate that the yeast isolates from kefir and traditional kefir-like products can bind to and detoxify AFB1, thereby reducing its harmful effects.

The Medical journal of Malaysia, May 1, 2022

Objective: Carbapenems are effective agents to treat multidrug�resistant (MDR) strains of bacte... more Objective: Carbapenems are effective agents to treat multidrug�resistant (MDR) strains of bacteria, including Pseudomonas aeruginosa. However, there is a potential threat of emergence of carbapenem�resistant P. aeruginosa (CRPA). The aim of this study was to determine antibiotic susceptibility patterns and metallo�beta�lactamase (MBL)�mediated resistance in clinical P. aeruginosa isolates. Materials and Methods: Different clinical specimens were subjected to conventional culture�based identification of P. aeruginosa. Antimicrobial susceptibility patterns and MBL production were evaluated using the Kirby�Bauer and combined double�disk synergy test methods, respectively. Multiplex polymerase chain reaction was performed to investigate the presence of the blaIMP, blaVIM, blaNDM, blaSPM, and blaSIM genes. Results: A total of 71 clinical P. aeruginosa isolates were recovered, of which 28.17 were identified as CRPA. The most active antibiotics were colistin and polymyxin B...

BMC Research Notes, 2021

Objective The purpose of the present study was to investigate the antimicrobial susceptibility pa... more Objective The purpose of the present study was to investigate the antimicrobial susceptibility pattern, biofilm production, and the presence of biofilm genes among the S. maltophilia clinical isolates. A total of 85 clinical isolates of S. maltophilia were collected from patients referred to several hospitals. Susceptibility to antibiotics was investigated by disc diffusion method according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). By the crystal violet staining method, the capability of biofilm formation was examined. The genes associated with biofilm production were investigated by the PCR-sequencing techniques. Results All isolates were resistant to doripenem, imipenem, and meropenem. Minocycline, trimethoprim/sulfamethoxazole and levofloxacin exhibited the highest susceptibility of 100%, 97.65%, and 95.29%, respectively. The results of crystal violet staining assay showed that all isolates (100%) form biofilm. Moreover, 24 (28.23%), 32 (37.65%)...

Journal of global antimicrobial resistance, 2019

OBJECTIVES Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a serious challenge... more OBJECTIVES Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a serious challenge and poses a threat to public health worldwide. This study aimed to determine drug susceptibility of A. baumannii, and then, investigate oxacillinase-encoding determinants and their association with ISAba1 sequence in CRAB isolates. METHODS This study was performed on A. baumannii isolates recovered from patients with burn wound infections during 2013. All isolates were evaluated for antimicrobial susceptibility by disc agar diffusion method. Minimum inhibitory concentration (MIC) of five antibiotics, including imipenem, meropenem, polymyxin B, colistin, and tigecycline was determined against all CRAB isolates. PCR assay was performed in CRAB isolates to determine distribution of blaOXA determinants and ISAba1 insertion upstream of each corresponding genes. RESULTS A total of 65A. baumannii isolates were recovered during the one-year period. CRAB strains accounted for 96.92% of total iso...

Arak Medical University Journal, 2015

Background: Due to increasing antibiotic resistance, it is important to identify the antimicrobia... more Background: Due to increasing antibiotic resistance, it is important to identify the antimicrobial activity of herbs. This experimental study aimed to evaluate the antimicrobial activity of herbal extracts of common hop (Humulus lupulus) and oak (Quercus castaneifolia) against several microbial standard strains. Materials and Methods: The alcoholic and aqueous extracts of H. lupulus and Q. castaneifolia were extracted. The inhibitory effects of herbal extracts were evaluated against the microbial standard strains (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans) by both agar diffusion and macrobroth dilution methods. In the agar diffusion method, concentrations of extracts were 125, 250, 500 and 1000 mg/ml. In order to determine the MIC, serial dilutions were prepared with a range from 1 to 512 mg/ml. Results: Alcoholic extract of both hop and oak showed higher inhibitory effect against microbial standard strains, compared to the aqueous extract...

Molecules, 2021

The treatment of viral disease has become a medical challenge because of the increasing incidence... more The treatment of viral disease has become a medical challenge because of the increasing incidence and prevalence of human viral pathogens, as well as the lack of viable treatment alternatives, including plant-derived strategies. This review attempts to investigate the trends of research on in vitro antiviral effects of curcumin against different classes of human viral pathogens worldwide. Various electronic databases, including PubMed, Scopus, Web of Science, and Google Scholar were searched for published English articles evaluating the anti-viral activity of curcumin. Data were then extracted and analyzed. The forty-three studies (published from 1993 to 2020) that were identified contain data for 24 different viruses. The 50% cytotoxic concentration (CC50), 50% effective/inhibitory concentration (EC50/IC50), and stimulation index (SI) parameters showed that curcumin had antiviral activity against viruses causing diseases in humans. Data presented in this review highlight the potent...

Acta Microbiologica et Immunologica Hungarica, 2021

In this study, we focused on the emergence of extensively drug-resistant (XDR), pandrug-resistant... more In this study, we focused on the emergence of extensively drug-resistant (XDR), pandrug-resistant (PDR), and hypervirulent Klebsiella pneumoniae (hvKP) in Iran. During 2018 to 2020 a total of 52 K. pneumoniae isolates were collected from different clinical specimens. The hvKP isolates were identified by PCR amplification of virulence and capsular serotype-specific genes. Hypermucoviscous K. pneumoniae (hmKP) were identified by string test. Carbapenem-resistant hvKP (CR-hvKP), multidrug-resistant hvKP (MDR-hvKP), extensively drug-resistant hvKP (XDR-hvKP), and pandrug-resistant hvKP (PDR-hvKP) were determined by disc diffusion method, Carba-NP test and PCR method. XDR-hvKP isolates were typed by multilocus sequence typing (MLST). Among all K. pneumoniae isolates 14 (26.9%) were identified as hvKP and 78.6% (11/14) of them were hmKP however, none of the classic K. pneumoniae (cKP) isolates were hmKP. The predominant capsular serotype of hvKP was K2 (42.85%) followed by K1 (35.71%). Th...

Aquatic organisms are a source of organic compounds that hold various features such as medical an... more Aquatic organisms are a source of organic compounds that hold various features such as medical and nutritional activities. Within the framework of an antimicrobial activity study of marine macro-organisms from the Persian Gulf, bioactive compounds of the sea cucumber Holothuria leucospilota were extracted from the whole body using chloroform and methanol. The extracts were evaluated for their antibacterial effects against methicillin-resistant (MRSA) and staphylococcal enterotoxins producing (SEA, SEB) Staphylococcus aureus strains. Activities have been determined using three methods: disk diffusion tests, minimum bactericidal concentration (MBC), and minimum inhibitory concentration (MIC). The results demonstrate that methanol and chloroform extracts have an inhibitory effect on the growth of all strains at MIC concentrations up to 100 mg/ml. Also, chloroform extracts demonstrate bactericidal activity against SEB in concentrations of about 100 mg/ml. The extracts also show bacteric...

Journal of Global Antimicrobial Resistance, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

BMC Research Notes, 2020

Objectives Pseudomonas aeruginosa is known as a leading cause of nosocomial infections worldwide.... more Objectives Pseudomonas aeruginosa is known as a leading cause of nosocomial infections worldwide. Antimicrobial resistance and biofilm production, as two main virulence factors of P. aeruginosa, are responsible for the persistence of prolonged infections. In this study, antimicrobial susceptibility pattern and phenotypic and genotypic characteristics of biofilm of P. aeruginosa were investigated. Results A total of 80 clinical P. aeruginosa isolates were obtained. Isolates showed resistance to all antibiotics with a rate from 12.5% (n = 10) against amikacin and piperacillin/tazobactam to 23.75% (n = 19) to levofloxacin. Multidrug-resistant P. aeruginosa accounted for 20% (n = 16). 83.75% (n = 67) of isolates showed biofilm phenotype. All three biofilm-related genes were found simultaneously in 87.5% (n = 70) of P. aeruginosa and 13.5% (n = 10) of the isolates had none of the genes tested. From the results of the present study, combination therapy including an anti-pseudomonal beta-l...

Infection and Drug Resistance, 2019

The loss of polycationic antimicrobial peptides, polymyxins, due to adhesion to plastics is an im... more The loss of polycationic antimicrobial peptides, polymyxins, due to adhesion to plastics is an important subject matter that influences in vitro susceptibility testing, including minimum inhibitory concentration (MIC) assays. This review reminds us that this issue can serve as a significant source of variation in the MIC values for polymyxins against Gramnegative bacteria.

Journal of Global Antimicrobial Resistance, 2019

OBJECTIVES Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a serious challenge... more OBJECTIVES Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a serious challenge and poses a threat to public health worldwide. This study aimed to determine drug susceptibility of A. baumannii, and then, investigate oxacillinase-encoding determinants and their association with ISAba1 sequence in CRAB isolates. METHODS This study was performed on A. baumannii isolates recovered from patients with burn wound infections during 2013. All isolates were evaluated for antimicrobial susceptibility by disc agar diffusion method. Minimum inhibitory concentration (MIC) of five antibiotics, including imipenem, meropenem, polymyxin B, colistin, and tigecycline was determined against all CRAB isolates. PCR assay was performed in CRAB isolates to determine distribution of blaOXA determinants and ISAba1 insertion upstream of each corresponding genes. RESULTS A total of 65A. baumannii isolates were recovered during the one-year period. CRAB strains accounted for 96.92% of total isolates. Polymyxin B, colistin, and tigecycline were the most effective agents in CRAB isolates, with a susceptibility rate of 100%, 87.3%, and 65.08%, respectively. CRAB isolates carrying oxacillinase determinants accounted for as follow: "blaOXA-51-like, 100%; blaOXA-23-like, 74.6%; blaOXA-24/40-like, 47.62%; and blaOXA-235-like, 12.69%". ISAba1, ISAba1-blaOXA-23-like, and ISAba1-blaOXA-51-like were detected in 100%, 41.26% and 1.58% of CRAB isolates. Co-occurrence of blaOXA determinants or inserted ISAba1 upstream of corresponding genes was associated with increased MICs (≥128μg/ml) to carbapenems. CONCLUSIONS Emergence of high-level carbapenem-resistant A. baumannii with blaOXA and ISAba1-blaOXA family in burn patients is a matter of increasing clinical concern, emphasizing need to infection control efforts to limit such problematic bacteria.

Acta microbiologica et immunologica Hungarica (Print), May 8, 2021

Carbapenems are employed to treat infections caused by Gram-negative bacteria including Klebsiell... more Carbapenems are employed to treat infections caused by Gram-negative bacteria including Klebsiella pneumoniae. This research is aimed to perform phenotypic detection of b-lactamases and molecular characterization of NDM-1 positive K. pneumoniae isolates. Another objective is to investigate NDM-1 producing K. pneumoniae among children in Iran. From 2019 to 2020, altogether 60 K. pneumoniae isolates were acquired from various patients in certain Iranian hospitals. Antimicrobial susceptibility testing was performed by disk diffusion and broth microdilution methods. In addition, mCIM and eCIM were used to confirm the production of carbapenemases and metallo-beta-lactamases (MBLs), respectively. Detection of resistance genes namely, bla NDM-1 , bla IMP , bla VIM , bla KPC , bla OXA-48-like , bla CTX-M , bla SHV , bla TEM , and mcr-1 was performed by PCR and confirmed by DNA sequencing. Multilocus sequence typing (MLST) was employed to determine the molecular typing of the strains. According to the findings, the highest rate of carbapenem resistance was detected against doripenem 83.3% (50). Moreover, 31.7% (19) were resistant to colistin. Further to the above, altogether 80% (48) were carbapenemase-producing isolates and among them 46.7% (28) of the isolates were MBL and 33.3% (20) isolates were serine b-lactamase producer. According to the PCR results, 14 isolates produced bla NDM-1. Remarkably, four bla NDM-1 positive isolates were detected in children. In addition, these isolates were clonally related as determined by MLST (ST147, ST15). Altogether ten bla NDM-1 positive isolates were ST147 and four bla NDM-1 positive isolates were ST15. Based on the results, the emergence of NDM-producing K. pneumoniae among children is worrying and hence, it is necessary to develop a comprehensive program to control antibiotic resistance in the country.

Jundishapur Journal of Microbiology, Nov 21, 2018

Background: The ability of extended spectrum beta-lactamases (ESBLs) production is one of the mai... more Background: The ability of extended spectrum beta-lactamases (ESBLs) production is one of the main mechanisms for the emergence of antibiotic resistance in Escherichia coli and Klebsiella pneumoniae. Objectives: The aim of this study was to evaluate the occurrence of IS903, IS26, and ISEcp1 insertion elements among the CTX-Mproducing K. pneumoniae and E. coli isolates from patients with leukemia in Tehran. Methods: Eighty E. coli and K. pneumoniae isolates were recovered from patients admitted to hospitals of Tehran. Antibiotic susceptibility tests were performed by Kirby-Bauer disc diffusion and broth microdilution methods. Detection of ESBL producers was evaluated by phenotypic confirmatory test. The presence of IS903, IS26, and ISEcp1 insertion elements in CTX-M-positive E. coli and K. pneumoniae isolates was investigated by PCR-sequencing methods. Results: The rate of resistance of 80 E. coli and K. pneumoniae isolates against the nine antibiotics was as follows: 100% to ampicillin, 15% to amikacin, 51% to ciprofloxacin, 30% to gentamicin, 58% to ceftriaxone, 10% to imipenem, 63% to cefotaxime, 51% to levofloxacin, and 55% to ceftazidime. Using phenotypic confirmatory test revealed that 51 (63.75%) isolates were ESBL producers. The prevalence of CTX-M-1, CTX-M-2, CTX-M-9, CTX-M-8, and CTX-M-25 genes was 87.5%, 13.75%, 23.75%, 10%, and 0%, respectively. IS903, IS26, and ISEcp1 elements were detected in 93.75%, 71.25%, and 100% of the isolates, respectively. Conclusions: This study indicates that the high prevalence of antibiotic resistance, IS and CTX-M-producing E. coli, and K. pneumoniae isolates could be a major concern and highlights the need for infection control measures.

Oman Medical Journal, Nov 1, 2016

ethicillin-resistant Staphylococcus aureus (mrSa) is an important nosocomial pathogen infecting d... more ethicillin-resistant Staphylococcus aureus (mrSa) is an important nosocomial pathogen infecting defenseless individuals in hospitals throughout the world. 1-3 There are growing numbers of studies implying the etiologic role of coagulasenegative Staphylococci (ConS) in disease in immunocompromised patients, and the increased prevalence of multidrug-resistant strains. 4-6 These species have the ability to survive in medical facilities for months. 7 The emergence and rise of antibiotic resistance among Staphylococci is a burden in health care facilities and communities. 8 biocides (antiseptics, disinfectants, and preservatives) are chemical compounds applied to inactivate or destroy microorganisms in various settings (e.g., the health care sector, agriculture and the food industry). 9-11 by the mid-1900s, many biocidal compounds were in common use as industrial preservatives and in the medical field. 10,11 Today, biocides have become an integral part of the industrialized world and are invaluable compounds in the control of human and animal pathogens. 12 large amounts of biocides are therefore consumed within the different settings, including the medical environment where they are used for disinfection, antisepsis, and cleaning. 9 a wide variety of biocidal agents, including quaternary ammonium compounds (QaCs), such as benzalkonium chloride (baC) and benzethonium chloride (bZT) and divalent cations like chlorhexidine digluconate (CHdG) original article

International Journal of Molecular and Clinical Microbiology, Jun 1, 2013

Aquatics are a source of bioactive compounds that these compounds have different properties such ... more Aquatics are a source of bioactive compounds that these compounds have different properties such as antimicrobial activity. In this study, antibacterial activity of methanol, chloroform and hexane extracts from body wall, gonad and intestine of sea cucumber Holothuria leucospilota was evaluated against Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus. Bioactive compounds of body wall, gonad and intestine of the sea cucumber Holothuria leucospilota collected from the north coast of the Persian Gulf were extracted using methanol, chloroform and hexane. The antibacterial activity was determined using the serial dilution method. The minimum inhibitory concentration and minimum bactericidal concentration was evaluated by broth micro dilution method. Results demonstrated that the P.aeruginosa was shown to be the most sensitive microorganism. All concentrations of methanol extracts from body wall, gonad and intestine did not show antibacterial activity against B.subtilis and S.aureus. Methanol extracts of gonad and intestine and chloroform extract from body wall showed no antibacterial activity against P. aeruginosa. Hexane extract from gonad had no inhibitory effect on the growth of B. subtilis in any of the concentrations. Other extracts had antibacterial effect in certain concentrations studied. None of the extracts showed any bactericidal effect against B. subtilis. Based on findings of this study, sea cucumber extracts can be considered as a natural antibiotic in the future research.

Indian Journal of Medical Research, 2018

: Overexpression of efflux pumps is a cause of acquired resistance to fluoroquinolones in Acineto... more : Overexpression of efflux pumps is a cause of acquired resistance to fluoroquinolones in Acinetobacter baumannii. The present study was done to investigate the presence and overexpression of AdeABC efflux system and to analyze the sequences of AdeR-AdeS regulatory system in ciprofloxacin-resistant A. baumannii isolates. : Susceptibility of 50 clinical A. baumannii isolates to ciprofloxacin, imipenem, ceftazidime, cefepime and gentamicin antimicrobials was evaluated by agar dilution method. Isolates were screened for the evidence of active efflux pump. Isolates were also examined for adeR-adeS and adeB efflux genes by polymerase chain reaction (PCR). The adeR and adeS regulatory genes were sequenced to detect amino acid substitutions. Expression of adeB was evaluated by quantitative reverse-transcriptase PCR. : There were high rates of resistance to ciprofloxacin (88%), ceftazidime (88%), cefepime (74%) and imipenem (72%) and less resistance rate to gentamicin (64%). Phenotypic assay showed involvement of active efflux in decreased susceptibility to ciprofloxacin among 16 isolates. The 12.27-fold increase and 4.25-fold increase were found in adeB expression in ciprofloxacin-full-resistant and ciprofloxacin-intermediate-resistant isolates, respectively. Several effective mutations, including A91V, A136V, L192R, A94V, G103D and G186V, were detected in some domains of AdeR-AdeS regulators in the overexpressed ciprofloxacin-resistant isolates. The results of this study indicated that overexpression of the AdeABC efflux pump was important to reduce susceptibility to ciprofloxacin and cefepime in A. baumannii that, in turn, could be triggered by alterations in the AdeR-AdeS two-component system. However, gene expression alone does not seem adequate to explain multidrug resistance phenomenon. These results could help plan improved active efflux pump inhibitors.

Expert Review of Anti-infective Therapy

Social Science Research Network, 2023

Medical Laboratory Journal

Background and objectives: Aflatoxin B1 (AFB1) is the most toxic aflatoxin produced by a large nu... more Background and objectives: Aflatoxin B1 (AFB1) is the most toxic aflatoxin produced by a large number of Aspergillus species. Successful detoxification of this toxin is an important attempt to improve community health. The aim of this study was to evaluate reducing effects of yeasts isolates from kefir and traditional kefir-like fermented beverages on AFB1 in a broth medium. Methods: Polymerase chain reaction-sequencing was carried out to identify the yeast isolates from kefir and kefir-like beverages. Effects of the isolates on AFB1 adsorption and biotransformation in peptone dexterose broth medium were evaluated by using high performance liquid chromatography. Results: Saccharomyces cerevisiae and Kluyveromyces marxianus were isolated from kefir and kefir-like beverages and resulted in 46% and 53% AFB1 adsorption, respectively. The isolates 27Y and 2Y caused 7% toxin biotransformation, while 10% toxin biotransformation was achieved by the isolate 18Y. Conclusion: Our results indicate that the yeast isolates from kefir and traditional kefir-like products can bind to and detoxify AFB1, thereby reducing its harmful effects.

The Medical journal of Malaysia, May 1, 2022

Objective: Carbapenems are effective agents to treat multidrug�resistant (MDR) strains of bacte... more Objective: Carbapenems are effective agents to treat multidrug�resistant (MDR) strains of bacteria, including Pseudomonas aeruginosa. However, there is a potential threat of emergence of carbapenem�resistant P. aeruginosa (CRPA). The aim of this study was to determine antibiotic susceptibility patterns and metallo�beta�lactamase (MBL)�mediated resistance in clinical P. aeruginosa isolates. Materials and Methods: Different clinical specimens were subjected to conventional culture�based identification of P. aeruginosa. Antimicrobial susceptibility patterns and MBL production were evaluated using the Kirby�Bauer and combined double�disk synergy test methods, respectively. Multiplex polymerase chain reaction was performed to investigate the presence of the blaIMP, blaVIM, blaNDM, blaSPM, and blaSIM genes. Results: A total of 71 clinical P. aeruginosa isolates were recovered, of which 28.17 were identified as CRPA. The most active antibiotics were colistin and polymyxin B...

BMC Research Notes, 2021

Objective The purpose of the present study was to investigate the antimicrobial susceptibility pa... more Objective The purpose of the present study was to investigate the antimicrobial susceptibility pattern, biofilm production, and the presence of biofilm genes among the S. maltophilia clinical isolates. A total of 85 clinical isolates of S. maltophilia were collected from patients referred to several hospitals. Susceptibility to antibiotics was investigated by disc diffusion method according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). By the crystal violet staining method, the capability of biofilm formation was examined. The genes associated with biofilm production were investigated by the PCR-sequencing techniques. Results All isolates were resistant to doripenem, imipenem, and meropenem. Minocycline, trimethoprim/sulfamethoxazole and levofloxacin exhibited the highest susceptibility of 100%, 97.65%, and 95.29%, respectively. The results of crystal violet staining assay showed that all isolates (100%) form biofilm. Moreover, 24 (28.23%), 32 (37.65%)...

Journal of global antimicrobial resistance, 2019

OBJECTIVES Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a serious challenge... more OBJECTIVES Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a serious challenge and poses a threat to public health worldwide. This study aimed to determine drug susceptibility of A. baumannii, and then, investigate oxacillinase-encoding determinants and their association with ISAba1 sequence in CRAB isolates. METHODS This study was performed on A. baumannii isolates recovered from patients with burn wound infections during 2013. All isolates were evaluated for antimicrobial susceptibility by disc agar diffusion method. Minimum inhibitory concentration (MIC) of five antibiotics, including imipenem, meropenem, polymyxin B, colistin, and tigecycline was determined against all CRAB isolates. PCR assay was performed in CRAB isolates to determine distribution of blaOXA determinants and ISAba1 insertion upstream of each corresponding genes. RESULTS A total of 65A. baumannii isolates were recovered during the one-year period. CRAB strains accounted for 96.92% of total iso...

Arak Medical University Journal, 2015

Background: Due to increasing antibiotic resistance, it is important to identify the antimicrobia... more Background: Due to increasing antibiotic resistance, it is important to identify the antimicrobial activity of herbs. This experimental study aimed to evaluate the antimicrobial activity of herbal extracts of common hop (Humulus lupulus) and oak (Quercus castaneifolia) against several microbial standard strains. Materials and Methods: The alcoholic and aqueous extracts of H. lupulus and Q. castaneifolia were extracted. The inhibitory effects of herbal extracts were evaluated against the microbial standard strains (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans) by both agar diffusion and macrobroth dilution methods. In the agar diffusion method, concentrations of extracts were 125, 250, 500 and 1000 mg/ml. In order to determine the MIC, serial dilutions were prepared with a range from 1 to 512 mg/ml. Results: Alcoholic extract of both hop and oak showed higher inhibitory effect against microbial standard strains, compared to the aqueous extract...

Molecules, 2021

The treatment of viral disease has become a medical challenge because of the increasing incidence... more The treatment of viral disease has become a medical challenge because of the increasing incidence and prevalence of human viral pathogens, as well as the lack of viable treatment alternatives, including plant-derived strategies. This review attempts to investigate the trends of research on in vitro antiviral effects of curcumin against different classes of human viral pathogens worldwide. Various electronic databases, including PubMed, Scopus, Web of Science, and Google Scholar were searched for published English articles evaluating the anti-viral activity of curcumin. Data were then extracted and analyzed. The forty-three studies (published from 1993 to 2020) that were identified contain data for 24 different viruses. The 50% cytotoxic concentration (CC50), 50% effective/inhibitory concentration (EC50/IC50), and stimulation index (SI) parameters showed that curcumin had antiviral activity against viruses causing diseases in humans. Data presented in this review highlight the potent...

Acta Microbiologica et Immunologica Hungarica, 2021

In this study, we focused on the emergence of extensively drug-resistant (XDR), pandrug-resistant... more In this study, we focused on the emergence of extensively drug-resistant (XDR), pandrug-resistant (PDR), and hypervirulent Klebsiella pneumoniae (hvKP) in Iran. During 2018 to 2020 a total of 52 K. pneumoniae isolates were collected from different clinical specimens. The hvKP isolates were identified by PCR amplification of virulence and capsular serotype-specific genes. Hypermucoviscous K. pneumoniae (hmKP) were identified by string test. Carbapenem-resistant hvKP (CR-hvKP), multidrug-resistant hvKP (MDR-hvKP), extensively drug-resistant hvKP (XDR-hvKP), and pandrug-resistant hvKP (PDR-hvKP) were determined by disc diffusion method, Carba-NP test and PCR method. XDR-hvKP isolates were typed by multilocus sequence typing (MLST). Among all K. pneumoniae isolates 14 (26.9%) were identified as hvKP and 78.6% (11/14) of them were hmKP however, none of the classic K. pneumoniae (cKP) isolates were hmKP. The predominant capsular serotype of hvKP was K2 (42.85%) followed by K1 (35.71%). Th...

Aquatic organisms are a source of organic compounds that hold various features such as medical an... more Aquatic organisms are a source of organic compounds that hold various features such as medical and nutritional activities. Within the framework of an antimicrobial activity study of marine macro-organisms from the Persian Gulf, bioactive compounds of the sea cucumber Holothuria leucospilota were extracted from the whole body using chloroform and methanol. The extracts were evaluated for their antibacterial effects against methicillin-resistant (MRSA) and staphylococcal enterotoxins producing (SEA, SEB) Staphylococcus aureus strains. Activities have been determined using three methods: disk diffusion tests, minimum bactericidal concentration (MBC), and minimum inhibitory concentration (MIC). The results demonstrate that methanol and chloroform extracts have an inhibitory effect on the growth of all strains at MIC concentrations up to 100 mg/ml. Also, chloroform extracts demonstrate bactericidal activity against SEB in concentrations of about 100 mg/ml. The extracts also show bacteric...

Journal of Global Antimicrobial Resistance, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

BMC Research Notes, 2020

Objectives Pseudomonas aeruginosa is known as a leading cause of nosocomial infections worldwide.... more Objectives Pseudomonas aeruginosa is known as a leading cause of nosocomial infections worldwide. Antimicrobial resistance and biofilm production, as two main virulence factors of P. aeruginosa, are responsible for the persistence of prolonged infections. In this study, antimicrobial susceptibility pattern and phenotypic and genotypic characteristics of biofilm of P. aeruginosa were investigated. Results A total of 80 clinical P. aeruginosa isolates were obtained. Isolates showed resistance to all antibiotics with a rate from 12.5% (n = 10) against amikacin and piperacillin/tazobactam to 23.75% (n = 19) to levofloxacin. Multidrug-resistant P. aeruginosa accounted for 20% (n = 16). 83.75% (n = 67) of isolates showed biofilm phenotype. All three biofilm-related genes were found simultaneously in 87.5% (n = 70) of P. aeruginosa and 13.5% (n = 10) of the isolates had none of the genes tested. From the results of the present study, combination therapy including an anti-pseudomonal beta-l...

Infection and Drug Resistance, 2019

The loss of polycationic antimicrobial peptides, polymyxins, due to adhesion to plastics is an im... more The loss of polycationic antimicrobial peptides, polymyxins, due to adhesion to plastics is an important subject matter that influences in vitro susceptibility testing, including minimum inhibitory concentration (MIC) assays. This review reminds us that this issue can serve as a significant source of variation in the MIC values for polymyxins against Gramnegative bacteria.

Journal of Global Antimicrobial Resistance, 2019

OBJECTIVES Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a serious challenge... more OBJECTIVES Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a serious challenge and poses a threat to public health worldwide. This study aimed to determine drug susceptibility of A. baumannii, and then, investigate oxacillinase-encoding determinants and their association with ISAba1 sequence in CRAB isolates. METHODS This study was performed on A. baumannii isolates recovered from patients with burn wound infections during 2013. All isolates were evaluated for antimicrobial susceptibility by disc agar diffusion method. Minimum inhibitory concentration (MIC) of five antibiotics, including imipenem, meropenem, polymyxin B, colistin, and tigecycline was determined against all CRAB isolates. PCR assay was performed in CRAB isolates to determine distribution of blaOXA determinants and ISAba1 insertion upstream of each corresponding genes. RESULTS A total of 65A. baumannii isolates were recovered during the one-year period. CRAB strains accounted for 96.92% of total isolates. Polymyxin B, colistin, and tigecycline were the most effective agents in CRAB isolates, with a susceptibility rate of 100%, 87.3%, and 65.08%, respectively. CRAB isolates carrying oxacillinase determinants accounted for as follow: "blaOXA-51-like, 100%; blaOXA-23-like, 74.6%; blaOXA-24/40-like, 47.62%; and blaOXA-235-like, 12.69%". ISAba1, ISAba1-blaOXA-23-like, and ISAba1-blaOXA-51-like were detected in 100%, 41.26% and 1.58% of CRAB isolates. Co-occurrence of blaOXA determinants or inserted ISAba1 upstream of corresponding genes was associated with increased MICs (≥128μg/ml) to carbapenems. CONCLUSIONS Emergence of high-level carbapenem-resistant A. baumannii with blaOXA and ISAba1-blaOXA family in burn patients is a matter of increasing clinical concern, emphasizing need to infection control efforts to limit such problematic bacteria.