Search tips
Search criteria


Important Notice

PubMed Central Canada to be taken offline in February 2018

On February 23, 2018, PubMed Central Canada (PMC Canada) will be taken offline permanently. No author manuscripts will be deleted, and the approximately 2,900 manuscripts authored by Canadian Institutes of Health Research (CIHR)-funded researchers currently in the archive will be copied to the National Research Council’s (NRC) Digital Repository over the coming months. These manuscripts along with all other content will also remain publicly searchable on PubMed Central (US) and Europe PubMed Central, meaning such manuscripts will continue to be compliant with the Tri-Agency Open Access Policy on Publications.

Read more

Results 1-7 (7)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
Document Types
1.  E6-Specific Detection and Typing of Human Papillomaviruses in Oral Cavity Specimens from Iranian Patients 
Iranian Biomedical Journal  2017;21(6):411-416.
Detection and quantification of human Papillomavirus (HPV) genome in oral carcinoma play an important role in diagnosis, as well as implications for progression of disease.
We evaluated tissues from 50 esopharyngeal cancers collected from different regions of Iran for HPV E6 using the two type-specific primers sets. E6 gene of HPV genotypes was amplified by specific primers. The sensitivity of PCR assay was analyzed and determined using HPV-DNA-containing plasmids. Real-time PCR was utilized to determine the prevalence and HPV viral load in patients with oral cavity squamous cell carcinoma.
Eighteen (36%) specimens were positive for HPV. Among the 18 positive specimens, 10 showed HPV-18 (55.55%), and 8 specimens were positive for HPV-11 (44.44%). Of the 18 infected specimens, 6 (33.32%) and 12 (66.65%) were identified as high-titer and low-titer viral load, respectively.
The PCR-based assay, developed in the current study, could be used for HPV detection, quantification, and genotyping in epidemiological and clinical studies.
PMCID: PMC5572438
Real-time PCR; Genotyping; Iran
2.  Frequency of Antiseptic Resistance Among Staphylococcus aureus and Coagulase-Negative Staphylococci Isolated From a University Hospital in Central Iran 
Oman Medical Journal  2016;31(6):426-432.
Reduced biocide susceptibility in Staphylococci is associated with various antiseptic resistance genes encoding efflux systems. Our aim was to determine the susceptibility to three disinfectant agents, including benzalkonium chloride (BAC), benzethonium chloride (BZT), and chlorhexidine digluconate (CHDG) among clinical isolates of Staphylococcus aureus and coagulase-negative Staphylococci (CoNS).
The minimum inhibitory concentration (MIC) of 60 methicillin-resistant S. aureus (MRSA), 54 methicillin-sensitive S. aureus (MSSA) and 51 CoNS isolates from a single hospital to three biocidal agents (BAC, BZT, and CHDG) was determined. Biocide resistance genes (qacA/B, smr, qacG, qacH, qacJ, and norA) were analyzed by the polymerase chain reaction assay.
All isolates had MICs for BAC and BZT from 0.25 to 8 µg/mL, and for CHDG from 0.5 to 64 µg/mL. qacA/B was the most common biocide resistance gene among all 165 Staphylococcus isolates (76; 46%), which comprised 38 (63.3%) MRSA, 14 (25.9%) MSSA, and 24 (47%) CoNS. Eleven (6.7%) and 24 (14.5%) isolates among the 165 Staphylococci carried smr and norA genes, respectively. In contrast, other resistance genes such as qacG, qacH, and qacJ were absent in all Staphylococci studied. The qacA/B and smr genes were detected concomitantly in 3% of isolates, and 23.6% strains of the total 165 Staphylococcus isolates were negative for each studied gene.
The carriage of several biocide resistance genes, including qacA/B, smr, and norA, alone or concurrently, is associated with reduced susceptibility. Use of antiseptics may select for antibiotic-resistant strains and assist their survival in the healthcare environment.
PMCID: PMC5099399  PMID: 27974958
Antiseptics; Methicillin-resistant Staphylococcus aureus
3.  Association between mutations in gyrA and parC genes of Acinetobacter baumannii clinical isolates and ciprofloxacin resistance 
We investigated the contribution of gyrA and parC mutational mechanism in decreased ciprofloxacin susceptibility of Acinetobacter baumannii isolated from burn wound infections.
Materials and Methods:
Ciprofloxacin susceptibility of 50 A. baumannii isolates was evaluated by disk diffusion and agar dilution methods. PCR and sequencing were performed for detection of mutation in gyrA and parC genes.
The 44 and 4 isolates of A. baumannii exhibited full and intermediate-resistant to ciprofloxacin, respectively. Overall, the 42 isolates with double mutations of gyrA and parC genes showed a higher level of ciprofloxacin resistance than the 3 isolates with single mutations of gyrA or parC.
Simultaneous mutations in gyrA and parC genes are expected to play a major role in high-level fluoroquinolone resistance in A. baumannii; albeit a single mutation in DNA topoisomerase IV could occasionally be associated with intermediate-resistance to these antimicrobials.
PMCID: PMC4509960  PMID: 26221488
Acinetobacter baumannii; Burn; Ciprofloxacin resistance; gyrA; parC
4.  Correlation of Ciprofloxacin Resistance with the AdeABC Efflux System in Acinetobacter baumannii Clinical Isolates 
Annals of Laboratory Medicine  2014;34(6):433-438.
Acinetobacter baumannii is one of the most important pathogens capable of colonization in burn patients, leading to drug-resistant wound infections. This study evaluated the distribution of the AdeABC efflux system genes and their relationship to ciprofloxacin resistance in A. baumannii isolates collected from burn patients.
A total of 68 A. baumannii clinical strains were isolated from patients hospitalized in Motahari Burns Center in Tehran, Iran. Ciprofloxacin susceptibility was tested by the disk diffusion and agar dilution methods. PCR amplification of the adeRS-adeB drug efflux genes was performed for all resistant and susceptible isolates. To assess the role of the drug efflux pump in ciprofloxacin susceptibility, carbonyl cyanide 3-chlorophenylhydrazone (CCCP) was used as an efflux pump inhibitor (EPI).
Approximately 95.6% of the Acinetobacter isolates were resistant to ciprofloxacin, with minimum inhibitory concentration (MIC) values ranging from 4 to ≥128 µg/mL. The susceptibility of 86.1% of the resistant isolates increased by factors of 2 to 64 in the presence of CCCP. All resistant isolates were positive for the adeRS-adeB genes, and 73.2% of them had mutations in the AdeRS regulatory system.
The results showed that AdeABC genes are common in A. baumannii, which might be associated with ciprofloxacin non-susceptibility, as indicated by the observed linkage to the presence of the genes essential for the activity of the AdeABC, several single mutations occurring in the adeRS regulatory system, and an increase of ciprofloxacin susceptibility in the presence of a CCCP EPI.
PMCID: PMC4215416  PMID: 25368818
Acinetobacter baumannii; Ciprofloxacin; Burns; Efflux pump genes; Resistance
5.  Detection of AdeABC efflux pump genes in tetracycline-resistant Acinetobacter baumannii isolates from burn and ventilator-associated pneumonia patients 
Acinetobacter baumannii is the most prevalent nosocomial pathogen which have been emerged in the past three decades worldwide. The aim of this study was to assess the distribution of the AdeABC efflux pump genes, associated with tetracycline resistance in Acinetobacter baumannii isolates collected from burn infection and Ventilator Associated Pneumonia (VAP).
Materials and Methods:
Ninety-eight A. baumannii isolates were collected from two different hospitals in Tehran, Iran. Tetracycline susceptibility testing was performed by disk diffusion and agar dilution methods according to the CLSI guidelines. The presence of adeSR, adeB, drug efflux system genes in resistant isolates was assessed by polymerase chain reaction (PCR). Carbonyl cyanide 3-chlorophenylhydrazone (CCCP) was used as a chemical inhibitor agent to assess the contribution of AdeABC efflux pump in tetracycline resistance isolates.
Approximately 48% (47 out of 98) of isolates showed resistance to tetracycline which 14 (14.2%) isolates were corresponded to burn infection and the remaining 33 (33.8%) strains were isolated from VAP. All tetracycline resistant isolates have AdeABC in PCR assay. The reduction of tetracycline MICs by using 50 μg/ml CCCP were as follows: in 18 isolates 2-4 fold reduction in MICs, 26 isolates showed 8 fold reduction,1 isolate showed 16 fold, 1 isolate showed 32 fold and the remaining 1 isolate showed 128 fold reduction in MICs.
The results showed significant correlation between tetracycline resistance and AdeABC efflux pump genes in resistant A. baumannii isolates.
PMCID: PMC4231381  PMID: 25400404
Acinetobacter baumannii; burns; efflux pump genes; Iran; tetracycline; ventilator associated penumonia
6.  PCR-based identification of methicillin-resistant Staphylococcus aureus strains and their antibiotic resistance profiles 
To evaluated the PCR for mecA gene compared with the conventional oxacillin disk diffusion method for methicillin-resistant Staphylococcus aureus (S. aureus) identification.
A total of 292 S. aureus strains were isolated from various clinical specimens obtained from hospitalized patients. Susceptibility test to several antimicrobial agents was performed by disk diffusion agar according to Clinical and Laboratory Standards Institute guidelines. The PCR amplification of the mecA gene was carried out in all the clinical isolates.
Among antibiotics used in our study, penicillin showed the least anti-staphylococcal activity and vancomycin was the most effective. The rate of methicillin-resistant S. aureus prevalence determined by oxacillin disk diffusion method was 47.6%; whereas, 45.1% of S. aureus isolates were mecA- positive in the PCR assay.
This study is suggestive that the PCR for detection of mecA gene is a fast, accurate and valuable diagnostic tool, particularly in hospitals in areas where methicillin-resistant S. aureus is endemic.
PMCID: PMC4025288  PMID: 25183100
Methicillin-resistant Staphylococcus aureus; Oxacillin disk diffusion; PCR; mecA gene
7.  Effect of Efflux Pump Inhibitor Carbonyl Cyanide 3-Chlorophenylhydrazone on the Minimum Inhibitory Concentration of Ciprofloxacin in Acinetobacter baumannii Clinical Isolates 
Acinetobacter baumannii is an important human pathogen with increasing notoriety in the recent years, as a causative organism of drug resistant nosocomial infections, particularly in immunocompromised patients hospitalized in burn centers.
The aim of this study was to determinate the role of efflux pump(s) in ciprofloxacin resistance of A. baumannii strains isolated from burn patients.
Materials and Methods:
Sixty-five A. baumannii strains were isolated from the burn patients hospitalized in Motahari Burns and Reconstruction Center in Tehran, Iran. Susceptibility test to ciprofloxacin was carried out by disk agar diffusion and agar dilution methods, according to the CLSI guidelines. Activity of the efflux system was evaluated using efflux pump inhibitor carbonyl cyanide 3-chlorophenylhydrazone (CCCP).
All Acinetobacter isolates were resistant to ciprofloxacin. The Minimum inhibitory concentration (MIC) range of ciprofloxacin in isolates was 4 to 128 µg/mL or greater. Moreover, susceptibility of strains to ciprofloxacin was highly increased in the presence of efflux pump inhibitor; So that, for 86.1% (56/65) of isolates, CCCP reduced the MIC by 2 to 64 folds.
Our findings are suggestive that efflux-based system may play a role in fluoroquinolone resistance in A. baumannii isolates, affecting hospitalized patients. The ability of Acinetobacter to acquire resistance to these potent antimicrobials by the efflux pump mechanism is a concern. Therefore, new strategies are required in order to eliminate the efflux transport activity from the resistant bacteria causing nosocomial infections and provide more appropriate approaches for treatment and management of troubling infections.
PMCID: PMC4138672  PMID: 25147654
Acinetobacter baumannii; Burn; Ciprofloxacin; Efflux Pumps; Carbonyl cyanide 3-chlorophenylhydrazone

Results 1-7 (7)