alka hasani

Tabriz University Of Medical Sciences, Faculty of Medicine, Faculty Member

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Comparative Transcriptional Signature Analysis of Peripheral Blood Mononuclear Cells in Early Stage of Hepatitis B-related Hepatocellular Carcinoma

Hepatitis Monthly

Background: Hepatocellular carcinoma (HCC) is a prevalent and life-threatening tumor with high mo... more Background: Hepatocellular carcinoma (HCC) is a prevalent and life-threatening tumor with high morbidity and mortality. Proper prediction and prognosis are incredibly stressed to diagnose HCC and increase patient survival. Objectives: This research aims to evaluate gene expression levels of pre-differentiated transcripts for those suffering from chronic hepatitis B (CHB) and HCC. Methods: To examine the previously analyzed peripheral blood mononuclear cells (PBMCs) transcriptomic array data, we selected seven differentially expressed genes (DEGs) in normal versus CHB and CHB versus HCC (CD44, SP3, USP8, E2F2, UFM1, IFN regulative factor binding protein 2 (IRF2BP2), and T-cell intracellular antigen 1 (TIA1)). The study included individuals with treatment-naïve CHB (n = 30) and primary HCC (n = 25) and healthy controls (n = 15). Subsequently, the expression of genes was assayed using qRT-PCR. A phylogenetic evaluation was performed using direct sequencing of HBsAg. Results: In HCC pat...

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Drug Users and Antimicrobial Susceptibilitystaphylococcus Aureus Nasalcarriage Among Injecting and Non-Injecting

American Journal of Infectious Diseases, 2013

Contribution of Arginine Catabolic Mobile Element and Copper and Mercury Resistance Element in Methicillin-Resistant Staphylococcus aureus: A Vantage Point

Hindawi, 2022

Di erent clones of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) are d... more Di erent clones of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) are dominating geographically. One of the signi cant, hypervirulent, CA-MRSA and a signi cant health concern clones is USA3000, found worldwide regionally with varying frequencies. e clone harbors several mobile genetic elements (MGEs) including, arginine catabolic mobile element (ACME) and copper and mercury resistance genes (COMER), accomplished by horizontal gene transfer from S. epidermidis. Evidence suggests that ACME and COMER have a more prominent role in enhancing bio lm capacity and ultimately persistent infections. is review highlights the comprehensive view on ACME and COMER structure, their distribution, and the mechanism of action along with pathogenetic features of USA3000 encompassing their role in bio lm formation, adhesion, quorum sensing, resistance to antibiotics, chemotaxis, and nutrient uptake. We also provided an insight into the role of ACME and COMER genes in the survival of bacterium. Our results shed light on the emergence of two independent clones possessing ACME (North American) and COMER (South American) elements which later disseminated to other regions. ACME and COMER both are adjacent to staphylococcal cassette chromosome mec type IV (SCCmec IV). e acquisition of mecA, followed by COMER or ACME has been shown as a signi cant factor in the rise and fall of MRSA strains and their complex ability to adapt to hostile environments. e presence of ACME increases tness, thereby allowing bacteria to colonize the skin and mucous membrane while COMER contributes to genetic stability by knocking over the copper-mediated killing in macrophages. Evidence suggests that ACME and COMER have a more prominent role in enhancing bio lm capacity and ultimately persistent infections. Interestingly, ACME strains have been shown to possess the ability to counteract skin acidity, thereby allowing increased skin colonization. A profound understanding of MGEs in S. aureus plays an important role in the prevention of epidemic clones.

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Uropathogenic Escherichia coli endeavors: an insight into the characteristic features, resistance mechanism, and treatment choice

Springer, 2023

Uropathogenic Escherichia coli (UPEC) are the strains diverted from the intestinal status and acc... more Uropathogenic Escherichia coli (UPEC) are the strains diverted from the intestinal status and account mainly for uropathogenicity. This pathotype has gained specifications in structure and virulence to turn into a competent uropathogenic organism. Biofilm formation and antibiotic resistance play an important role in the organism's persistence in the urinary tract. Increased consumption of carbapenem prescribed for multidrug-resistant (MDR) and Extended-spectrum-beta lactamase (ESBL)-producing UPECs, has added to the expansion of resistance. The World Health Organization (WHO) and Centre for Disease Control (CDC) placed the Carbapenem-resistant Enterobacteriaceae (CRE) on their treatment priority lists. Understanding both patterns of pathogenicity, and multiple drug resistance may provide guidance for the rational use of anti-bacterial agents in the clinic. Developing an effective vaccine, adherence-inhibiting compounds, cranberry juice, and probiotics are non-antibiotical approaches proposed for the treatment of drug-resistant UTIs. We aimed to review the distinguishing characteristics, current therapeutic options and promising non-antibiotical approaches against ESBL-producing and CRE UPECs.

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Methicillin resistant and susceptible Staphylococcus aureus: Appraising therapeutic approaches in the Northwest of Iran

DOAJ (DOAJ: Directory of Open Access Journals), Mar 1, 2013

Aptitude of Uropathogenic Escherichia coli in Renal Transplant Recipients: A Comprehensive Review on Characteristic Features, and Production of Extended Spectrum β-Lactamase

Current Microbiology

Urinary tract infection is the most common infection in almost half of the renal transplant patie... more Urinary tract infection is the most common infection in almost half of the renal transplant patients. The development of UTI in these patients may progress to bacteremia, acute T cell-mediated rejection, impaired allograft function, or allograft loss, along with the increased risk of hospitalization and death. Among various pathogens implicated, Uropathogenic E. coli (UPEC), especially sequence type 131 (ST131), is the most virulent and multidrug-resistant pathogen. High antimicrobial resistance to most β-lactam antibiotics, mediated by extended spectrum β-lactamases (ESBLs) produced by UPEC, is a challenge in the clinical management of UTIs in kidney transplant recipients. Indeed, multidrug resistance to β-lactam antibiotics is a direct consequence of ESBL production. Resistance to other antibiotics such as aminoglycosides, fluoroquinolones, and trimethoprim-sulphamethoxazole has also been reported in ESBLs-producing UPEC, which reduces the therapeutic options, rising healthcare-associated costs and subsequently leads to renal failure or even graft loss. In this review, we aimed to discuss the post-transplant risk factors of UTI, UPEC virulence factors (VF), and the related factors including quorum sensing, and stress resistance genes. Furthermore, we searched for the current treatment strategies and some of the alternate approaches proposed as therapeutic options that may affirm the treatment of ESBL-producing UPEC.

Immunogenicity of Chitosan-Based Non-invasive Vaccine Strategy Against <i>Mycobacterium tuberculosis</i>

Immunoanalysis, Mar 27, 2023

Background: In spite of Bacillus Calmette-Guerin (BCG) vaccination, still tuberculosis caused by ... more Background: In spite of Bacillus Calmette-Guerin (BCG) vaccination, still tuberculosis caused by Mycobacterium tuberculosis remains a problematic impediment that requires perspective management. The aim of this study was to evaluate the immunogenicity of chitosan nanoparticles containing recombinant mycobacterial proteins and adjuvant in the Balb/C mice through a non-invasive nasal inhalation delivery route and measure the level of cytokines interferongamma (IFN-γ), interleukin-4 (IL-4), and IL-17. Methods: Thirty mice in five different groups were vaccinated through inhalation with compounds set in different combinations. Two weeks after the last nasal delivery, IFN-γ, IL-4, and IL-17 were measured in spleen cell culture supernatants. Results: The IFN-γ and IL-17 concentrations were found to increase in the groups that received chitosan nanoparticles containing protein and adjuvant alone or as a BCG booster. Our study showed that the chitosan nanoparticle containing protein and adjuvant induced a Th1 response. However, the groups that first received BCG and then chitosan nanoparticles containing protein and adjuvant had the greatest Th1 response in terms of IFN-γ and IL-17 production in all the groups. Conclusion: Our findings showed that the vaccine designed to be administered through the nasal mucosa well stimulates cellular immunity and enhances the BCG vaccine's effectiveness.

format_quoteMice received a 50µg antigen dose of vaccine containing recombinant proteins on specified days, affirming the immunization protocol.format_quote

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Molecular Detection and Characterization of the Staphylococcus epidermidis and Staphylococcus haemolyticus Isolated from Hospitalized Patients and Healthcare Workers in Iran

BioMed Research International, Jan 6, 2023

Background. The present study is aimed at surveying the antibiotics resistance profile, biofilm f... more Background. The present study is aimed at surveying the antibiotics resistance profile, biofilm formation ability, staphylococcal cassette chromosome mec (SCCmec) types, and molecular epidemiology of Staphylococcus epidermidis and Staphylococcus haemolyticus isolated from hospitalized patients and healthcare workers in four teaching hospitals in Iran. Methods. In total, 43 Staphylococcus epidermidis and 12 Staphylococcus haemolyticus were isolated from hospitalized patients, and 19 Staphylococcus epidermidis and 7 Staphylococcus haemolyticus isolated from healthcare workers were included in the present study. The antimicrobial resistance profile of isolates was determined using the disk diffusion method. Moreover, the resistance of isolates to methicillin was identified using the cefoxitin disk diffusion test. The microtiter-plate test was used for quantifying biofilm formation. Moreover, the frequency of icaA and icaD genes was determined using PCR assay. The molecular epidemiology of methicillin-resistant isolates was determined using SCCmec typing and pulsed-field gel electrophoresis methods. Results. Among all coagulase-negative staphylococci isolates, the highest resistance rate (81.5%) was seen for cefoxitin and cotrimoxazole. All of the isolates were susceptible to linezolid. Out of the 66 mecA-positive isolates, the most common SCCmec type was the type I (n = 23; 34.8%) followed by type IV (n = 13; 19.7%). Using pulsed-field gel electrophoresis (PFGE) assay, 27 PFGE types including 14 common types and 13 singletons were obtained among 51 methicillin-resistant S. epidermidis (MRSE) isolates. Moreover, among 12 methicillin-resistant S. haemolyticus (MRSH) isolates, 8 PFGE types were detected, of which 5 PFGE types were singletons. Conclusion. The high rate of resistance to antibiotics as well as the possibility of cross-infection shows the importance of a pattern shift in the management and controlling programs of coagulase-negative staphylococci, especially in healthcare centers. Clinical trial registration. The present study is not a clinical trial study. Thus, a registration number is not required.

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Effect of QRDR Mutations on Ciprofloxacin Resistance in Clinical Isolates of Pseudomonas aeruginosa

Journal of Ardabil University of Medical Sciences, Jul 1, 2016

Background & objectives: Fluoroquinolones have important role in treatment of P. aeruginosa infec... more Background & objectives: Fluoroquinolones have important role in treatment of P. aeruginosa infections. The main mechanism of fluoroquinolones resistance in P. aeruginosa is mutations in the quinolone-resistance-determining region (QRDR) of gyrA and parC genes. The aim of this study was to investigate the role of these mutations in ciprofloxacin resistance in different clinical isolates of P. aeruginosa. Methods: A total of 75 clinical P. aeruginosa isolates were collected from different university-affiliated hospitals in Tabriz. Minimum inhibitory concentrations (MICs) of ciprofloxacin were evaluated by Etest assay. DNA sequences of the QRDR of gyrA and parC were determined by dideoxy chain termination method. Results: From 75 isolates, 77.33% were resistant to ciprofloxacin. No amino acid changes were detected in gyrA or parC genes of the ciprofloxacin susceptible isolates. Thr-83→Ile substitution in gyrA was observed in all ciprofloxacin resistant isolates. About 90% of them had Ser-87→Leu substitution in parC. Geometric mean MICs of ciprofloxacin were different for various clinical isolates of P. aeruginosa which had the same situation in type and location of gyrA and parC mutations. Moreover, the geometric mean MIC in isolates from urine was significantly (p<0.05) higher than isolates from tracheal aspirates. Conclusion: Mutations in gyrA and parC genes are the major mechanisms for ciprofloxacin resistance in clinical isolates of P. aeruginosa. Moreover, the role of different effective factors in fluoroquinolone resistance can be different in various clinical isolates of P. aeruginosa.

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Investigation and Identification of the nuc, fem B mecA and aac(6′)/aph(2′′)-Ia Genes in the Staphylococcus Aureus Isolated from Northwest Iran by Multiplex PCR Method

Medical journal of Tabriz University of Medical Sciences and Health Services, May 15, 2013

Backgrounds and Objectives: Staphylococcus aureus is one of the most common pyogenic bacteria pos... more Backgrounds and Objectives: Staphylococcus aureus is one of the most common pyogenic bacteria possessing highest potentiality to develop resistance to antibiotics. Emergence of resistance towards the most common antibiotics such as aminoglycoside and vancomycin has added burden to the existing MRSA situation. Aminoglycosides are important bactericidal agents. The aminoglycoside resistance is due to drug inactivation by plasmidor transposon-mediated aminoglycoside modifying enzymes. The aim of this study was to develop a Multiplex-PCR assay for rapid and accurate detection of S. aureus and its resistance genes to aminoglycoside and

Methicillin resistant and susceptible Staphylococcus aureus: Appraising therapeutic approaches in the Northwest of Iran

PubMed, Mar 1, 2013

Background and objectives: Staphylococcus aureus is a versatile organism causing mild to life thr... more Background and objectives: Staphylococcus aureus is a versatile organism causing mild to life threatening infections. The major threat of this organism is its multidrug resistance. The present study was carried out to investigate in - vitro activity of conventional antibiotics routinely prescribed for methicillin resistant S. aureus (MRSA) and methicillin sensitive S. aureus (MSSA) infections in the Northwest of Iran and other alternating therapeutic agents which are recommended for Gram positive organisms. Materials and methods: Clinical isolates of S. aureus were subjected to multiplex PCR for simultaneous speciation and detection of methicillin resistance. Antibacterial susceptibility pattern was determined using disk diffusion. The Minimum Inhibitory Concentrations (MICs) were determined using E-test strips. Results: The results revealed presence of nuc gene in all S. aureus isolates detected phenotypically earlier whereas, mecA gene was observed in 54% of strains. On disk diffusion and MIC determination assay, all MRSA and MSSA strains were susceptible to mupirocin (except one MRSA strain), linezolid and teicoplanin. Six vancomycin intermediate S. aureus strains were detected (VISA) with MIC= 4µg/mL, 5 of them being MRSA. In disk diffusion assay, 17.3% and 3.7% of isolates showed resistance to rifampin and fusidic acid, respectively. However, MIC50 and MIC90 tests shows promising in - vitro impact. Conclusion: In - vitro mupirocin was found as an effective prophylactic ointment for nasal S. aureus eradication. Our data emphasize the performance of surveillance exercises to outline the existing antibiotics prescription policies and to slow down the emergence of multidrug resistant strains.

Emergence of colistin resistant Pseudomonas aeruginosa at Tabriz hospitals, Iran

PubMed, Feb 1, 2016

Background and objectives: The prevalence of multidrug resistant Pseudomonas aeruginosa is the ma... more Background and objectives: The prevalence of multidrug resistant Pseudomonas aeruginosa is the main reason of new drugs resurgence such as colistin. The main objectives of this study were to determine the antibiotic resistance pattern and the rate of colistin resistance along with its correlation with overexpression of MexAB-OprM and MexXY-OprM efflux pumps among P. aeruginosa isolates. Materials and methods: Hundred clinical isolates were collected from 100 patients during 6 months in 2014. Susceptibility to the eight antibiotics was investigated using Kirby-Bauer and agar dilution methods. The Quantitative Real-time PCR was used to determine the expression levels of efflux genes. Results: Resistance rates to various antibiotics were as follows: ticarcillin (73%), ciprofloxacin (65%), aztreonam (60%), ceftazidime (55%), gentamicin (55%), imipenem (49%), piperacillin/tazobactam (34%) and colistin (2%). In disk diffusion method, only two isolates were non susceptible to colistin, however in agar dilution method the two isolates were confirmed as resistant and two others were intermediate resistant. Sixty eight (68%) isolates were multi-drug resistant and 10 isolates were susceptible to all tested antibiotics. Both colistin resistant isolates showed overexpression of both efflux pumps, but two intermediate resistant isolates exhibited reduction of efflux genes expression. Conclusions: Emergence of colistin resistance is increasing in P. aeruginosa indicating great challenge in the treatment of infections caused by MDR strains of this organism in Iran. ParRS may promote either induced or constitutive resistance to colistin through the activation of distinct mechanisms such as MDR efflux pumps, and LPS modification.

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Prevalence of extended-spectrum β-lactamases and characterization of integron class 1 in extended spectrum β lactamase-producing klebsiella pneumoniae in sina hospital ,Tabriz 2012

Medical journal of Tabriz University of Medical Sciences and Health Services, Aug 28, 2017

Background: The existence of beta-lactmase among gram-negative bacteria such as Klebsiella pneumo... more Background: The existence of beta-lactmase among gram-negative bacteria such as Klebsiella pneumoniae, as a significant pathogen in nosocomial infection is the most important cause of resistance against betalactam antibiotics family. Class 1 integrons are mobile genetic elements which are mostly prevalent in drug-resistant bacteria. This study was conducted to determine the prevalence of phenotypic and genotypic ESBL-producing strains as well as the incidence of integron class 1 in ESBL-producing strains. Methods: Sixty three isolates of K.pneumoniae, confirmed by biochemical and phenotypic tests, were collected within six months. Susceptibility test was carried out by Disk diffusion method. Prevalence of ESBL producing strains were determined by using Combined Disk Test. Presence of bla TEM , bla SHV gene family and class I integron were detected by PCR technique. Results: Forty five (71.4%) of isolates were ESBL-producing .TEM and SHV gene family were existed in 66.6% and 68.9% of ESBL -producing isolates, respectively. Class I integron were detected in 24 (65%) and 19 (63.3%) of SHV and TEM positive strains, respectively. Conclusion: In present study, increasing level of ESBL producing isolates were confirmed. Also, this study intensely demonstrates the role of integron in the dissemination of ESBL-mediated resistance among the nosocomial isolates .Overall, using the proper treatment procedure according to the antibiogram pattern of the strains is specifically recommended.

Prevalence of Ampicillin, Gentamicin and Vancomycin-Resistant Enterococci in Fecal Samples from Hospitalized and Non-Hospitalized Patients in Three Educational Hospitals of Tabriz University of Medical Sciences

Medical journal of Tabriz University of Medical Sciences and Health Services, Oct 8, 2011

Materials and Methods: This study was performed by collecting stool or rectal swab specimens. Obt... more

<p>Quorum Quenching: A Potential Target for Antipseudomonal Therapy</p&gt

Infection and Drug Resistance, Aug 1, 2020

There has been excessive rate of use of antibiotics to fight Pseudomonas aeruginosa (P. aeruginos... more There has been excessive rate of use of antibiotics to fight Pseudomonas aeruginosa (P. aeruginosa) infections worldwide, which has consequently caused the increased resistance to multiple antibiotics in this pathogen. Due to the widespread resistance and the current poor effect of antibiotics consumed to treat P. aeruginosa infections, finding some novel alternative therapeutic methods are necessary for the treatment of infections. The P. aeruginosa biofilms can cause severe infections leading to the increased antibiotic resistance and mortality rate among the patients. In this regard, there are no approaches that can efficiently manage these infections; therefore, novel and effective antimicrobial and antibiofilm agents are needed to control and treat these bacterial infections. Quorum sensing inhibitors (QSIs) or quorum quenchings (QQs) are now considered as potential therapeutic alternatives and/or adjuvants to the current failing antibiotics, which can control the virulence traits of the pathogens, so as a result, the host immune system can quickly eliminate bacteria. Thus, the aims of this review article were presenting a brief explanation of the research reports on the natural and synthetic QSIs of P. aeruginosa, and the assessment of the current understanding on the QS mechanisms and various QQ strategies in P. aeruginosa.

format_quoteFungal secondary metabolites inhibited pathogenic factors and biofilm production in P. aeruginosa, showing promise for natural QSIs in therapy.format_quote

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Prevalence and Antimicrobial Susceptibility Patterns of ESBL, AmpC and Carbapenemase-producing Enterobactericeae Isolated from Hospitalized Patients in Azerbaijan, Iran

PubMed, 2018

The current study was conducted to determine prevalence and antimicrobial susceptibility patterns... more The current study was conducted to determine prevalence and antimicrobial susceptibility patterns, ESBL, AmpC and carbapenemase- producers among clinical isolates of Enterobacteriaceae. Three hundred and seven non-duplicative clinical isolates were collected from hospitalized patients in five medical centers in Azerbaijan, Iran. Initial screening for β-lactamase production was performed using disc agar diffusion according to Clinical Laboratory Standards Institute (CLSI) guidelines. Phenotypic confirmatory tests was done using total ESBL/AmpC confirm kit, KPC/MBL and OXA-48 confirm kit according to manufacturer's instructions. The overall prevalence of ESBL, AmpC, and carbapenemase-producing strains were 42.7% (131/307), 14.0%(43/307) and 4.9% (15/307), respectively. The prevalence of ESBLs was 38.35%, 64.9% and 35.7% for E. coli, K. pneumoniae and E. cloacae, respectively. Carbapenemase activity was only observed among 15 K. pneumoniae isolates and detected phenotypes include MBL (9/57, 15.8%), KPC (4/57, 7.0%), and OXA-48 (2/57, 3.5%). Fourteen out of 307 isolates (4.6%) were recognized to have ESBL or AmpC hyper-producer with decreased cell wall permeability phenotype. All 4 shigella strains were positive for ESBL and 4 isolates of P. mirabilis, 2 isolates of M. morganii and 1 seratia spp. were detected as AmpC producer. The only C. freundii strain isolated was positive for both ESBL and AmpC. This study reveals high prevalence of multidrug-resistant (MDR) β-lactamase-producing Enterobactericeae reaching 89.5%. Imipenem and meropenem showed potent antibacterial activities against all MDR β-lactamase-producers except for carbapenemase producers. After carbapenems, amikacin, piperacillin/tazobactam and amoxicillin/clavulanic acid were second the most effective drugs against β-lactamase-producing E. coli isolates.

Short Communication High Prevalence of Metallo-b-Lactamase-Producing Acinetobacter baumannii in a Teaching Hospital in Tabriz, Iran

Metallo-b-lactamase (MBL)-producing Acinetobacter baumannii has become a growing therapeutic conc... more Metallo-b-lactamase (MBL)-producing Acinetobacter baumannii has become a growing therapeutic concern worldwide. The aims of this study were to evaluate the antimicrobial susceptibility of A. baumannii isolates and to determine the prevalence of MBL genes among carbapenem nonsusceptible isolates. During a period of 16 months (March 2008-June 2009), 100 isolates of A. baumannii were collected from different clinical specimens of inpatients admitted to the largest teaching hospital in the northwest of Iran. All isolates were tested for antimicrobial susceptibility by Kirby-Bauer disk diffusion method. Carbapenem non-susceptible isolates were further screened for production of MBL by Etest and were then subjected to PCR for detection of MBL genes of types bla IMP and bla VIM. Among 63 carbapenem (imipenem and meropenem) non-susceptible isolates of A. baumannii, 31 (49z) were found to be MBL producers. Of 31 MBL-producing isolates, 19 (61z) carried the bla IMP gene and 9 (29z) carried the bla VIM gene. All MBL-producing isolates were multidrug resistant. This is the first report of IMP and VIM types among MBL-producing A. baumannii in Iran.

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Detection of Genes That Encoding the Collagen (Cna) and Fibronectin (FnB) binding Protein of Staphylococcus aureus Isolates by Multiplex- PCR

Medical journal of Tabriz University of Medical Sciences and Health Services, Dec 5, 2012

Background and Objectives: Staphylococcus aureus encode variety of virulence factors genes which ... more Background and Objectives: Staphylococcus aureus encode variety of virulence factors genes which may induce various infections individually or synergistically. The aim of this study was to assess virulence factors including collagen binding (Cna), and Fibronectin binding (FnB) proteins at molecular level, in S.aureus strains isolated from clinical and nasal specimens of patients admitted to University Teaching Hospitals of Tabriz. Materials and Methods: In a limited period, from July to February 2009, 1936 various clinical specimens and 504 specimens from anterior nares from cardiac patients were collected. The S.aureus isolates were identified by phenotypic methods and later confirmed by PCR with detection of nuc and femB genes. MRSA strains were identified using disk diffusion method and later confirmed by detection of mecA gene. Multiplex PCR was performed to detect the above mentioned genes as well as to spot virulence factors coded by cna and fnb genes. Results: From 1936 various clinical samples and 504 nasal specimens, 121 and 214 nonduplicate S.aureus strains were isolated respectively. cna was identified in 80.99% clinical and 17.29% nasal S.aureus strains. cna had higher prevalence in isolates from septic arthritis, osteomyelitis and endocarditis. fnb was identified in 65.29% clinical and 54.67% nasal S.aureus strains and had higher prevalence in isolates from endocarditis, osteomyelitis and burn associated wounds. In both clinical and nasal S.aureus strains, prevalence of virulence factors in MRSA was higher than MSSA. Conclusion: The results of this research indicated that simultaneous detection of nuc, femB and mecA genes not only helps for identification of ُS.aureus isolates, but also is specific and useful for rapid detection of MRSA isolates. Higher prevalence of virulence factors in clinical isolates as compared to strains responsible for colonization and in MRSA over MSSA, shows the role of these factors in invasion and pathogenesis.

Distribution of enterotoxin genes and AGR types in Staphylococcus aureus (Enterotoxins and AGR types in S.aureus)

Der Pharmacia Lettre, 2016

Staphylococcus aureus is a major human pathogen harboring several virulence factors and super ant... more Staphylococcus aureus is a major human pathogen harboring several virulence factors and super antigens (Sag) or staphylococcal enterotoxins (SEs). These factors are associated with the presence of agr (Accessory Gene Regulator) locus that controls the expression of several of them. We aimed to determine the prevalence of super antigens and agr groups in 151 methicillin resistant and sensitive S. aureus and to investigate possible relationships between them. A series of six multiplex PCR were conducted. Gradual increase in methicillin resistant S. aureus isolates was evident in this study. Additionally, steady decline in agr II, III and IV types with emergence of agr type I as predominant type was a significant feature. Seventy nine toxin genotypes were observed, with the most common genotype being sea-sek-seq. A meaningful relationship between the major toxin genes, methicillin resistance and agr type 1 was observed. Enterotoxin gene cluster (egc)1 was more common than egc2. The overall prevalence of virulence factors corresponds with that seen in other European countries; however preferential association in this study between agrI and sea-sek-seq combination may serve as efficient triggering signal of virulence in clinical S.aureus isolates.

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Study on prevalence of extended spectrum β lactamase producing gram negative bacilli in clinical specimens isolated from hospitalized patients in Tabriz Sina Hospital

Medical journal of Tabriz University of Medical Sciences and Health Services, Oct 6, 2010

Background and Objectives: â-lactam antimicrobials represent the most common agents used for trea... more Background and Objectives: â-lactam antimicrobials represent the most common agents used for treatment of bacterial infections. â-lactamase production among gram negative bacteria is one of the leading cause of antibiotic resistance worldwide. The persistent exposure of bacterial strains to a multitude of â-lactams has induced dynamic and continuous production and mutation of â-lactamases in these bacteria, expanding their activity even against the newly developed antibiotics. Extended-spectrum â-lactamase (ESBL) producing bacteria are main problems for the current antimicrobial resistance study groups. This study aimed at evaluating the frequency of ESBL producing gram negative bacilli isolated from hospitalized patients. Materials and Methods: In an analytic-descriptive setting, 191 Gram negative bacteria isolated from hospitalized patients admitted in different wards of Sina Hospital, Tabriz were evaluated during a 15-month period. Broth dilution, double disc synergy and E-test were employed for assessing the presence of ESBL-producing organisms. Acinetobacter and Pseudomanas species were excluded due to technical limitations for evaluating the presence of ESBL in these bacteria. The probable risk factors for the presence of ESBL-producing Gram negative bacilli were also evaluated. Results: Ninety three (49%) isolates were found as the ESBL-producing bacteria. These included Klebsiella pneumoniae (62.9%), Escherichia coli (49.2%) and Enterobacter spp. (19.2%) isolates. Citrobacter spp and Serratia spp. isolates were also found as â-lactamase producing. The duration of stay, hospitalization in ICU, prolonged use of antibiotics, infection with Klebsiella species, catheter usage and previous hospitalization during the last 3 months were significantly related to the presence of ESBL-producing bacilli (P<0.05). The mortality rate was significantly higher in patients infected with ESBL-producing bacteria (11.8% vs. 2%; P=0.041). Conclusion: The current study showed that the rate of infection with ESBL-producing gram negative bacilli is notable; so preventive policy should be considered, particularly regarding the antibiotic prescriptions.

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