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Aptamers are nucleic acid (Ribonucleic acid (RNA) and single strand deoxyribonucleic acid (ssDNA)) with a length of approximately 25–80 bases that can bind to particular target molecules, similar to monoclonal antibodies. Due to their many benefits, which include a long shelf life, minimal batch-to-batch variations, extremely low immunogenicity, the possibility of chemical modifications for improved stability, an extended serum half-life, and targeted delivery, they are receiving a lot of attention in a variety of clinical applications. The development of high-affinity modification approaches has attracted significant attention in aptamer applications. Stable three-dimensional aptamers that have undergone chemical modification can engage firmly with target proteins through improved non-covalent binding, potentially leading to hundreds of affinity improvements. This review demonstrates how cutting-edge methodologies for aptamer discovery are being developed to consistently and effectively construct high-performing aptamers that need less money and resources yet have a high chance of success. Also, High-affinity aptamer modification techniques were discussed.

Abstract Background This study aimed to investigate the phylogenetic characterization and virulence traits of uropathogenic Escherichia coli (UPEC) isolated from kidney transplant patients (KTPs) as well as non-KTPs and analyze the clonal distribution of Extended spectrum β-lactamases (ESBLs)-producing UPEC containing bla CTX-M gene. Methods To this end, we determined virulence marker and the phylogenetic characterization of UPEC in non-KTPs (n = 65) and KTPs (n = 46). The non-KTPs were considered the control group of the study. Also, according to the Achtman scheme, we performed multilocus sequence typing to assess the relationship between twenty-nine of ESBL-producing isolates containing bla CTX-M gene. Results According to the results of PCR assay, the prevalence of virulence factor genes ranged from 0% (cnf and papG III) to 93.7% (fimH). Also, KTP isolates significantly differed from non-KTP isolates only in terms of the prevalence of pap GI elements. Moreover, the most frequent UPEC isolates were in phylogenetic group B2, followed by group D (18.9%), and group A (13.5%). Furthermore, except for phylogenetic group C, there was no significant correlation between phylogenetic distribution in KTPs and non-KTPs. Additionally, MLST analysis of bla CTX-M carrying isolates identified 18 unique sequence types (ST) the most common of which was ST131 (24.1%), followed by ST1193 (10.3%), while fourteen STs were detected only once. Conclusions The results further revealed significant differences between the UPEC isolates from KTPs and non-KTPs regarding the phylogroups C and PAI gene. Based on MLST analysis, we also observed a relatively high diversity in UPEC isolates obtained from KTPs and non-KTPs. Moreover, clonal complex (CC) 131 and ST131 were found to be the most prevalent clones and ST types, respectively. Besides, for the first time, ST8503 were reported in KTPs. These results suggested regular studies on characterization of UPEC isolates among KTPs.

Abstract Objectives Group B Streptococcus (GBS) is an important opportunistic bacteria that causes a wide range of infections including neonatal sepsis, meningitis, pneumonia, soft tissue and urinary tract infections (UTI). The aim of this study was to evaluate the antimicrobial susceptibility patterns, surface proteins and capsular types of GBS isolates. Results 100 of UTI isolates were confirmed as GBS. Antimicrobial susceptibility pattern showed that 95% of GBS isolates were resistant to tetracycline, followed by erythromycin (52%), clindamycin (47%), levofloxacin (9%) and penicillin, cefepime, cefotaxime, and ceftriaxone each with (8%), and vancomycin 1%. Common capsular types were III, Ib, V, II, Ia and IV respectively and the distribution of surface protein genes was as follows: rib (40%), alpha-c (22%), alp2/3 (18%) and epsilon (15%), and alp4 gene was not detected in the isolates. Our findings showed the relationship between capsular types with Alpha-like proteins, as well as reduced sensitivity to antibiotics, so the performance of antibiotic surveillance programs is recommended.

Abstract Objectives Enterococcus faecalis as part of the normal floras of human gastrointestinal and genitourinary tracts are an important cause of nosocomial infections. The present study aimed to investigate the prevalence of genes encoding antimicrobial resistance and genetic relatedness of clinical isolates of E. faecalis among Iranian hospitalized patients. Results Antibiotic susceptibility testing results indicated that 53 (22.8%) out of 232 E. faecalis isolates were vancomycin resistant (MIC ≥ 256 μg/ml). All of the 53 vancomycin-resistant E. faecalis isolates carried the vanA and ermB genes; whereas aac (6′)-Ie aph (2″), msrA, and ermA gene were found in 96.2%, 30.2% and 3.8% of vancomycin-resistant isolates, respectively. ERIC-PCR typing revealed that 53 vancomycin-resistant isolates were classified into 14 ERIC types. In our results, the high level of resistance to gentamicin, erythromycin and vancomycin in enterococci isolates were mainly related to the presence of aac (6′)-Ie aph (2″), ermB and vanA genes, respectively. Meanwhile, ERIC-PCR analysis demonstrated that most of the evaluated isolates have a close genetic relatedness.

Background: Staphylococcus aureus (S. aureus) is one of the most important pathogens in burn infections colonized in the nose and increase the risk of infections. Methods: Overall, 85 S. aureus isolates were isolated from clinical and nasal hospitalized patients and health care workers (HCWs) in a burn unit and non-burn units in Isfahan from June 2016 and September 2016. Genes encoding penicillin-binding protein 2a (mecA) and adhesive surface proteins, including fibronectin-binding proteins (fnbA, fnbB), fibrinogen binding protein (fib), laminin-binding protein(eno), collagen binding protein (cna), elastin binding protein (ebps), intracellular adhesion operon (icaA and icaD) were detected using PCR method. Results: The rate of methicillin-resistant S. aureus (MRSA) among burn and non-burn isolates were 62% (18/29) and 25% (14/56), respectively. The most prevalent MSCRAMMs genes in burn units were eno (86%) and fib (66%). The most common gene pattern in burn center was icaA+fib+eno. The frequency of icaD, fib and ebpS was higher in clinical samples than nasal samples. No relation was found between the MSCRAMMs genes in the burn unit and non-burn units. Conclusion: The high prevalence of MRSA in burn center can be a new challenge for clinicians. The higher frequency of icaD, fib and ebpS in clinical isolates than nasal isolates may reflect the important role of these genes in colonization and pathogenesis of S. aureus.

BACKGROUND: Atherosclerosis and periodontitis are both chronic inflammatory diseases. Although a strong relationship between the two has already been established, the underlying mechanism is unknown. The present study was conducted aiming to detect the deoxyribonucleic acid (DNA) of Aggregatibacter actinomycetemcomitans (A.a), Campylobacter rectus (C.r), and Porphyromonas gingivalis (P.g) in subgingival and atherosclerotic plaques of patients with both chronic periodontitis and cardiovascular disease (CVD).METHODS: In this cross sectional study, patients with coronary artery disease (CAD) and moderate to severe periodontitis which were scheduled for coronary artery bypass grafting (CABG) were enrolled in the study. The subgingival plaques were collected before surgery. All samples were examined for the detection of selected periopathogens using polymerase chain reaction (PCR).RESULTS: The subgingival and atherosclerotic plaque samples of 23 patients were examined. The DNA of P.g, A.a, and C.r were found to be positive in 43.47%, 43.47%, and 78.26% of subgingival plaques, and 13.04%, 17.39%, and 8.69% of atherosclerotic plaques, respectively. In all cases, the bacterial species found in atherosclerotic plaques were also found in the subgingival plaques of the same patient.CONCLUSION: This study demonstrated the presence of periopathogens in atherosclerotic plaques of patients with chronic periodontitis. More studies are required to ascertain the exact role of these periopathogens in atherosclerotic plaque formation.

Background: Methicillin - resistant Staphylococcus aureus (MRSA) has become a considerable public health concern in the entire world due to the rapid spread of this bacterium in human community; also the epidemiology of MRSA has changed, as the isolation of MRSA strains from healthy and non-healthy patients. Therefore, the objective of this study is to determine the genetic diversity and antibiotic resistance profile of community-acquired (CA)-MRSA nasal carriage in the Iranian samples. Materials and Methods: A total of 25 CA-MRSA were isolated from the anterior nares of 410 healthy preschool children. All MRSA isolates were characterized by the detection of the toxic shock syndrome toxin-1 (TSST-1) and typed by γ-hemolysin genes, agr groups, and staphylococcal protein A (spa) typing. Kirby-Buyer antibiotic susceptibility testing was performed and interpreted as per the standard guidelines. Results: A total of 25 (6.1%) MRSA isolates were recovered from the anterior nares of 410 preschool children. Sixteen isolates (64%) were positive for the TSST-1 gene. Three agr specificity groups were determined, as follows: eight (32%) isolates belonged to agr Group I, five (20%) isolates belonged to agr Group II, and 12 (48%) isolates belonged to agr Group III. The repeated profiles of these spa types of 25 isolates were organized into eight different lineages groups. Five of lineages contained a single strain, three of lineages contained two strains, and three of lineages consisted of more than three strains. Conclusions: The results of our study show that the rate of MRSA in our region is significantly high. Additionally, spa type t037 was the predominant type among CA S. aureus.

Background: Nontuberculosis Mycobacterium (NTM) is the most common bacterium transferred to human from cow milk and products. The presence of these bacteria in the cow's milk stands as a public health concern particularly among those individuals consuming raw milk and dairy products. In this study the determination of 16S rRNA gene sequence method was used in order to evaluate the amount of Non tuberculosis Mycobacterium incidence and determine its types in milk samples gathered from Isfahan province. Methods: The cetyltrimethylammonium bromide (CTAB) and phenol chloroform were used for DNA extraction in isolates recognized as Non tuberculosis Mycobacterium, then using designed primers, 16S rRNA polymerase chain reaction was done and the types were determined after sequencing. Findings: 9 cultures, out of 119 samples gathered from Isfahan farms, were recognized positive in which 8 samples had M. fortuitum and one of them was M. gordonae. Conclusion: NTM incidence was 8.6% in evaluated milk samples. By using polymerase chain reaction (PCR) with 16SrRNA and sequencing, the fortuitum isolate type I incidence was 88.9% and Gordonae type III incidence was 11.1%. PCR method and sequencing of 16S rRNA gene which were used in this study are able to recognize isolates up to 100%.

Background and Objectives: Staphylococcus aureus is an important pathogen that can be colonized in the nose and increase the risk of spreading infections in hospitals. The present study aimed at determining the phenotypic and genotypic characterization of S. aureus strains isolated from patients and healthcare workers (HCWs) from a teaching hospital in Isfahan, Iran. Materials and Methods: This cross-sectional study was performed on 262 nasal swabs and 23 clinical isolates that were collected from a teaching hospital during February and April 2016. Staphylococcal cassette chromosome mec (SCCmec) and multilocus sequence typing (MLST) were performed for selected isolates. Results: Overall, 23% and 18% of healthcare workers and patients were carriers, respectively. Methicillin-resistant S. aureus (MRSA) rate was 13%, 33% and 52% in nasal HCWs, nasal patients, and clinical samples, respectively. The molecular typing of MRSA isolates revealed that the most common SCCmec type is SCCmec type III (88%). The highest rate of resistance was observed against tetracycline and erythromycin, with 48.7%. The most frequently detected toxin genes among S. aureus isolates were hla (99%) and sea (44%), moreover, pvl genes were detected in (40%) of MRSA isolates. The results of MLST showed 7 different sequence types (STs): ST859 (2/9), ST6 (2/9), ST639 (1/9), ST343 (1/9), ST239 (1/9), ST291 (1/9) and ST25 (1/9). Conclusion: Our results revealed that ST clones associated with healthcare-associated MRSA (HA-MRSA) are actively circulating among nasal carriage in our healthcare setting, and thus, effective infection control policies are needed to reduce nasal carriage in healthcare settings.

Background and Objectives: Macrolide, lincosamide and streptogramin B (MLSB) are noteworthy antibiotics for the treatment of Staphylococcus aureus infections. The purpose of this study, was to determine the phenotypic and genotypic characterization of macrolide resistance, among S. aureus, isolated from clinical samples and nasal swabs. Materials and Methods: Totally, 162 non-duplicate S. aureus isolates were collected from clinical samples and nasal swabs, from patients and healthcare workers (HCWs), between March 2016 and September 2016, at four teaching hospitals in Isfahan. The antibiotic resistance profile was determined using disk diffusion test and the presence of resistance genes was detected, using PCR. Results: Of 162 S. aureus isolates, 43.8% (71/162) and 34% (55/162) isolates were erythromycin-resistant and methicillin-resistant S. aureus (MRSA), respectively. The prevalence of constitutive MLSB (cMLSB), inducible MLSB (iMLSB), macrolide-streptogramin B-resistant (MSB) and lincosamide-streptogramin-A resistance (LSA) phenotype was 32%, 6%, 6% and 2%, respectively. The most common erythromycin resistance genes, in S. aureus isolates were ermC (35.2%), followed by ermA (20.4%) and msrA (17.3%). Meanwhile, msrA was detected in 43.6% of MRSA isolates. The frequency of coexistence of ermA+ermC+msrA, in S. aureus isolates was 7% and it was only detected in MRSA isolates. Conclusion: In the current study, cMLSB phenotype was the most common erythromycin resistance pattern and ermC was the most prevalent gene in erythromycin-resistant isolates. The results revealed that the various mechanisms of erythromycin resistance are expanding in Isfahan.

Background and aims: Staphylococcus aureus is known as one of the most important nosocomial pathogens, which may lead to several infections. The aim of this study was determining the enterotoxins A, C, and TSST-1 and molecular characterization of S. aureus strains with PFGE and MLST typing methods. Materials and methods: In the present study during the sixmonths sampling, fifty S. aureus strains were isolated from patients admitted to Al-Zahra university hospital. Antimicrobial susceptibility testing, Multiplex PCR for detection of enterotoxin A, C and TSST-1, pulse field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used for molecular typing. Results: In antibiogram the highest and lowest percentage of resistance was belonged to tetracycline and rifampin respectively. Multiplex PCR indicated that 30% of the strains harbored sea and 34% harbored sec genes. However, only 4% of our collected isolates had tsst gene. In PFGE method analysis on all S. aureus strains, a total of 19 different patterns were identified. Nine various sequence types in 27 selected S. aureus isolates were identified by MLST. Conclusions: Present study indicates a possible higher variability among our S. aureus strains by two different molecular typing methods; nevertheless four main common types (CT1, CT7, CT9, and CT11) with at least one toxin genes were determined.

Background: Excessive use of broad-spectrum antibiotics in hospitals has led to the emergence of highly resistant strains of Pseudomonas aeruginosa. The main mechanism of resistance of this bacterium to fluoroquinolones and carbapenems are the modification of type II topoisomerases (DNA gyrase and topoisomerase IV) and alterations in the OprD porin, respectively. The aim of this study was to examine for the occurrence of mutations related to fluoroquinolone resistance of gyrA and parC genes and mutational inactivation of oprD gene of clinical isolates using DNA sequencing technique. Methods: A total of 60 P. aeruginosa isolates were collected from the hospitalized patients in the Intensive Care Units (ICUs) of Al-Zahra hospital located in Isfahan, Iran. The pattern of sensitivity to antibiotics was determined using CLSI disk diffusion and MIC methods. The assay was based on a DNA sequencing method using polymerase chain reaction (PCR) for amplification and sequencing of the selected genes. Results: The results show that replacement of Ile for Thr-83 in gyrA was the only replacement, while other substitutions not observed. No mutations were found in parC. The most frequent amino acid alterations were E185Q, P186G, and V189T, found in five resistance isolates, However, nucleotide insertions and deletions mutations not observed. Conclusion: Our study suggested that mutation of gyrA and oprD genes may play a minor role in fluoroquinolone and carbapenem resistance and other mechanisms may contribute to the fluoroquinolone and carbapenem resistance of P. aeruginosa.

Introduction: Coagulase Negative Staphylococcus (CoNS) is considered as a major pathogen of nosocomial infections among immunosuppressed patients. Aim: The aim of this study was to identify the types of Staphylococcal Cassette Chromosome mec (SCCmec) and Panton-Valentine Leukocidin (PVL) gene among clinical Methicillin-Resistant S. epidermidis (MRSE) isolates collected from Isfahan. Materials and Methods: This cross-sectional study was performed from March 2014 to January 2015 at a tertiary care hospital of Isfahan, Iran. Antimicrobial susceptibility tests of S. epidermidis isolates were performed by the disc diffusion method. All the strains were screened for methicillin resistance based on resistance to cefoxitin (30 μg) disc and presence of mecA gene. Determination of SCCmec typing and PVL toxin gene were performed by PCR method. For categorical variables different groups were compared using the Chi-square test or Fisher exact test. A p-value of

Introduction: The major resistance mechanisms of Pseudomonas aeruginosa to fluoroquinolones and carbapenems are associated with the mutations in the genes gyrA and oprD encoding type II topoisomerases (DNA gyrase) and OprD porin, respectively. Method: In this cross-sectional study, sixty five clinical samples were collected from patients hospitalized in Al-Zahra Hospital of Isfahan, Iran. Susceptibility testing was performed by using disk diffusion and minimum inhibitory concentration (MIC) by E-test methods as recommended by Clinical Laboratory Standards Institute (CLSI). The assay was based on a DNA sequencing method using polymerase chain reaction (PCR). Results: The disk diffusion and E-test methods showed significant concordance in determining the in-vitro activity of the meropenem and ciprofloxacin against P. aeruginosa isolates. The mutations associated with antibiotic resistance were detected in the codon 83 of the gyrA gene, and various codons of the oprD gene. Conclusion: Our results showed that the main mechanism of fluoroquinolone resistance in P. aeruginosa is mediated primarily through mutations in gyrA and carbapenem resistance was driven mainly by the mutational inactivation of oprD gene.

Introduction: Methicillin-Resistant Staphylococcus aureus (MRSA) is responsible for an increasing number of serious hospital- and community-acquired infections. USA300 is known to be the most common cause of community-acquired infections, but recently there have been some reports on hospital-acquired infections caused by this strain. Methods: Totally 171 isolates of S. aureus were collected from different clinical samples in selected university hospitals in Mashhad, Tehran, and Isfahan cities. Then, they were assessed by agar screening and disk diffusion methods to determine their resistance to Methicillin. The isolated MRSA strains were confirmed by detection of mecA gene. The staphylococcal cassette chromosome mec (SCCmec), agr, and spa typing and also detection of Panton-Valentine leukocidin (PVL) and arginine catabolic mobile element (ACME) genes were performed on mecA harboring isolates. Multilocus sequence typing was performed on PVL/ACME positive MRSA strains. Results: We found a PVL/ACME positive MRSA isolate. Genetic evaluation results for this isolate produced the following profile: positive for mecA, pvl, arcA, and hla genes, negative for vanA, sec, and tst1, and belonged to agr I, SCCmec IV, sequence type 8 (ST8), and spa t008. Conclusion: Our results suggest a finding of USA300CA-MRSA isolate in Mashhad, Iran. This is an uncommon finding, because USA300 is routinely found in areas other than Middle East. A notable point about these isolates is that they belong to American Endemic clones.

Background: Staphylococcus aureus (S. aureus) is an important human pathogen associated with hospital- and community-acquired diseases, a wide range of infectious disease including minor skin disease to more sever and aggressive infections such as septicemia, pneumonia, endocarditis, and deep skin abscess. S. aureus has a high mortality rate of 35%. Therefore, it is crucial to identify the methicillin resistant S. aureus (MRSA) strains and implement the necessary treatment in order to control the spread of hospital infections. Methods: A total of 150 S. aureus isolates were collected from samples of patients admitted to Alzahra and Shariati hospitals in Isfahan, Iran. Polymerase chain reaction (PCR) for mecA gene was performed in all strains. Thereafter, the minimum inhibitory concentration (MIC) for oxacillin was carried out using agar dilution method. Then, antibiogram using disk diffusion for cephoxitin was performed according to Clinical and Laboratory Standards Institute (CLSI) regulations on isolates containing mecA gene. The three methods were then compared. Findings: Of the 150 samples, 62 samples (41.33%) were found to carry mecA gene using PCR. However, agar dilution for oxacillin found 56 of 62 samples (90.33%) to harbor mecA gene. Disk diffusion method revealed that 53 of 62 samples (85.48%) contain mecA gene. Conclusion: Agar dilution method was found to have a higher sensitivity in determining antibiotic sensitivity compared to disk diffusion method. However, PCR was identified as the ideal method for detecting MRSA strains; since a number of strains were found to be sensitive to oxacillin in phenotypic test due to lack of mecA expression while still containing the gene.

Background: Pseudomonas aeroginosa (P. aeroginosa) is one of the most important causes of hospital infections, especially in the intensive care unit (ICU). Increasing antibiotic-resistance of P. aeroginosa cause a lot of problems for patients and in some cases, lead to septicemia and death. The most important antibiotics used in the treatment of P. aeruginosa infection are ceftazidime, ciprofloxacin, imipenem and piperacillin mainly used in hospitals. Unsuitable and prolonged use of antibiotics has led to the emergence of multidrug (MDR) and pandrug resistant (PDR) strains. In fact, infections with MDR and PDR strains often result in increased cost of treatment, lengthy stay, and overall morbidity and mortality. This study aimed to determine the pattern of drug resistance in P. aeruginosa infection in ICU of Al-Zahra hospital (Isfahan, Iran). Methods: 66 isolates of P. aeruginosa from different clinical specimens from ICU wards of Al-Zahra hospital were isolated. Antibacterial susceptibility test for imipenem, meropenem, amikacin, gentamicin, ciprofloxacin, levofloxacin, aztreonam, cefepime, piperacillin, piperacillin/tazobactam and ceftazidime was performed using disk diffusion (Kirby-Bauer) method. Findings: Of 66 separated isolates, 51 (77.2%) were of MDR and 33 (50%) were of PDR strain. 75.8% were resistant to ceftazidime and 72.7% to piperacillin. In fact, most of isolates were resistant to both antibiotics. Conclusion: This study shows that overuse and misuse of antibiotics in hospitals has increased drug resistance and creation of the PDR and MDR strains. The results suggest that antibiotic resistance can be determined by choosing the appropriate drug to treat patients.

Background: Methicillin-Resistant Staphylococcus aureus (MRSA) is a major cause of Nosocomial and community infections that are becoming increasingly difficult to combat, because of emerging resistance to all classes of antibiotics. Moreover Panton-Valentine leukocidin (PVL) is an important virulence factor in S. aureus and causes white blood cell destruction, necrosis and accelerated apoptosis. The aim of this study was to determine the frequency of PVL-positive MRSA in cutaneous infections, for epidemiological purposes and also to determine antibiotic resistance of the isolates.Methods: Collectively, 56 isolates of S. aureus were obtained from Isfahan University of Medical sciences affiliated hospitals and confirmed with biochemical tests (coagulase, mannitol fermentation, and DNase). Then polymerase chain reaction (PCR) was used to detect pvl gene. Coagulase gene was used as internal control. The antibiotic susceptibility of all isolates to methicillin was determined using disk diffusion method.Results: Out of 56 isolates 14.3% were PVL positive that 37.5% were from abscess and 62.5% were from wound. Among all of these isolates 67.8% were MRSA and also 75% of PVL-positive isolates were MRSA.Conclusion: The prevalence of PVL positive MRSA in cutaneous isolates is high. Future works are necessary for a more complete understanding of distribution of these virulent isolates in nasal carriers to decrease the risk of infections.

Background Helicobacter pylori (H. pylori) is a gram negative curved bacilli colonized in the human stomach. It causes duodenal ulcer, gastritis and is associated with adenocarinoma. There might be a possible relationship between cagA, vacA and ice a genes and clinical outcomes. The aim of this study was to identify the frequency of vacA genotypes of H. pylori isolated from the upper gastrointestinal. Methods One hundred H. pylori strains were isolated from patients with different gastrointestinal disease who admitted to Isfahan Al-zahra hospital. Vac A alleles were typed using PCR with specific primers. Findings There were four Vac A mosaicsms, including 28 for s1a/m1 (28%), 23 for s1b/m1 (23%), 26 for s1a/m2 (26%) and 23 for s1b/m2 (23%), s2 form was not found. Conclusion The results showed there is no significant relationship between different genotypes of vacA and the related diseases. Key words: Helicobacter pylori, vac A, Adenocarinoma, Duodenal ulcer, Normal /Gastritis, PCR

مقدمه: پژوهش‌های پیشین نشان داده كه آنتی‌بادی‌های ضد استافیلوكوكوس اورئوس كپسول‌دار تایپ 5، موجب افزایش قابل توجهی در ایمنی خرگوش‌ها نشده است؛ یافتن ادجوانتی مناسب برای افزایش چشم‌گیر تیتر آنتی‌بادی برای تهیه‌ی واكسن ضد این باكتری ضروری به نظر می‌رسد. در این مطالعه، اثر ادجوانت هیدروكسید آلومینیوم، فروند و واكسن ثلاث (DTP) در افزایش تیتر آنتی‌بادی علیه این باکتری در خرگوش مورد بررسی قرار گرفته است. روش‌ها: 30 راس خرگوش سفید نر بالغ از نژاد نیوزلندی تهیه و به طور تصادفی به6 گروه تقسیم شدند. به گروه‌های مختلف سوسپانسیون کشته شده استافیلوکوکوس اورئوس کپسول دار تیپ 5 بدون ادجوانت، با هیدروکسید آلومینیوم، با ادجوانت فروند (در تزریق اول ادجوانت کامل و در تزریق دوم و سوم ادجوانت ناقص)، واکسن ثلاث، DTP به تنهایی و سرم فیزیولوژی استریل (به عنوان گروه شاهد) در 3 نوبت و به فواصل 21 روز تزریق شد. پیش از هر نوبت تزریق و 21 روز پس از سومین تزریق در همان روز از خرگوش خون‌گیری به عمل آمد و سرم آنها برای اندازه‌‌گیری تیتر آنتی‌بادی در فریزر نگهداری گردید. آزمایش آگلوتیناسون سرم‌ها با سوسپانسیون کشته شده باکتری بررسی شد و نتایج لوله‌های شاهد با بقیه‌ی لوله‌ها مقایسه و عکس رقت‌ها به عنوان تیتر آنتی‌بادی در نظر گرفته شد. یافته‌ها: در این پژوهش، ایمونیزاسیون خرگوش‌ها ضد باکتری و همراه با ادجوانت هیدروکسید آلومینیوم، ادجوانت فروند و DTP افزایش تیتر آنتی‌بادی ضد این باكتری مشاهده شد. میانگین تیتر آنتی‌بادی خرگوش‌های ایمونیزه شده با DTP بعد از تزریق نوبت سوم واكسن به طور معنی‌داری بیشتر از خرگوش‌های ایمونیزه شده با ادجوانت هیدروکسید آلومینیوم و فروند بود (049/0 =p ). همچنین میانگین تیتر آنتی‌بادی خرگوش‌های ایمونیزه شده با ادجوانت فروند بیشتر از خرگوش‌های ایمونیزه شده با ادجوانت هیدروکسید آلومینیوم (27/0 =p ) بود ولی این تفاوت معنی‌دار نبود. نتیجه‌گیری: در این بررسی، از بین ادجوانت هیدروکسید آلومینیوم، ادجوانت فروند و واكسن DTP، در خرگوش‌های ایمونیزه شده با DTP افزایش چشم‌گیر تیتر آنتی‌بادی ضد استافیلوكوكوس اورئوس كپسول‌دار تایپ 5 مشاهده شد. بنابراین پیشنهاد می‌شود برای ایجاد پاسخ ایمنی بهتر، از واكسن ثلاث (DTP) به عنوان ادجوانت در تركیب با سوسپانسیون كشته شده علیه این باكتری در انسان استفاده شود. واژگان کلیدی: استافیلوكوك اورئوس كپسول‌دار، ادجوانت، هیدروكسید آلومینیوم، فروند، واكسن ثلاث (DTP)، خرگوش.

Background and Objectives: Staphylococcus aureus is one of the main causatives of bovine mastitis. Resistance of some strains to methicillin, can complicate the treatment of its infections. On the other hand, enterotoxin production is also im- portant. Therefore, the aim of our study was to investigate the methicillin resistance and enterotoxin production in S. aureus isolates caused bovine mastitis. Materials and Methods: Four hundred and fifty milk samples were collected. After isolation of Staphylococcus aureus, MRSA strains were detected by cefoxitin disc diffusion and oxacillin agar screening methods. DNA was extracted by phenol – chloroform method and PCR was applied for mecA, sea and seb genes. SCCmec types of mecA gene were identified using multiplex-PCR. Results: Fifty-four (12%) S. aureus were isolated. Out of these, 10 and 9 MRSA strains identified by cefoxitin disc diffusion and oxacillin agar screening methods, respectively. All 10 MRSA isolates identified by cefoxitin disc diffusion, were positive for mecA gene and all of them belonged to SCCmec type IV. The sea genes were detected in 19 isolates and only two isolates were positive for seb genes. One isolate possessed both sea and seb genes. Conclusion: Findings of this study indicated that results of cefoxitin disc diffusion test is in concordance with the PCR for mecA gene and has a higher sensitivity compared to oxacillin agar screening method. Finally, Our findings suggest that enterotoxin A is the dominant type.

Background: Panton-Valentine leukocidin (PVL) is a gamma-toxin produced by Staphylococcus aureus encoded by genes lukS/lukF-PV with several single-nucleotide polymorphisms. A mutation at nucleotide position 527 results in substitution of histidine (H) to arginine (R) at amino acid 176. The groups defined based on the amino acid change, the “R isoform” group and the “H isoform” group. The purpose of this study was to determine the frequency of PVL gene isoforms in S. aureus strains isolated from patients at Al-Zahra Hospital Isfahan and molecular characterization of PVL-positive methicillin-resistant S. aureus(MRSA) strains including the detection of mecA gene and staphylococcal chromosomal cassette mec (SCCmec) typing. Materials and Methods: In this study, 130 isolates of S. aureus were collected from Al-Zahra Hospital. The PVL gene identified using polymerase chain reaction (PCR); PCR products were sequenced to identify the type of isoform. The molecular characterization of isolates of PVL-positive MRSA including detection of mecA gene by PCR and also SCCmec typing was performed by multiplex PCR. Results: Out of 130 isolates, 23% were positive for the presence of PVL genes. The PVL positive isolates were comprised 37% (11/30) of methicillin-resistant isolates and 63% (19/30) of methicillin-susceptible S. aureus (MSSA) isolates. The results showed that 17 isolated carrying isoform H and 13 isolated carrying the R isoform. Conclusion: The PVL gene was predominantly found in MSSA isolates. There was no relation between PVL isoforms and the presence of mecA and SCCmec types.

Background: The rising frequency of methicillin resistant Staphylococcus aureus (MRSA) has led to an increased use of antibiotics such as macrolide, lincosamide, streptogramin B (MLSB) for the treatment of S. aureus infections. Resistance to MLSBin S. aureus is commonly encoded by erm genes, which can be constitutive MLSB (cMLSB) or inducible MLSB (iMLSB). The purpose of this study was to determine the frequency of cMLSB, iMLSB, and MS phenotypes using D-test and polymerase chain reaction (PCR) methods. Materials and Methods: A total of 215 isolates of S. aureus were collected from January 2010 to May 2012 from Al-Zahra Hospital in Isfahan. PCR was performed for detection of mecA gene on all isolates using specific primers. The frequency of MLSB-resistant isolates was determined using D-test, and then a multiplex PCR was performed for detection of ermA, ermB, and ermC genes. Results: Among 215 S. aureus isolates examined, 82 (40.9%) were MRSA, and iMLSB, cMLSB, and MS resistance phenotypes had a frequency of 9 (4.18%), 58 (26.9%), and 11 (5.1%), respectively. Among nine isolates with iMLSBresistance phenotype, four isolates contained ermC gene, two isolates ermB gene, and one isolate ermA gene. Two isolates did not have any erm gene. Conclusion: In the current study, cMLSBwas the most frequent phenotype and ermC was the most common gene in iMLSBresistant phenotypes.

Background: The rapid emergence and spread of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has raised considerable public health concern in both developed and developing countries. The current study aimed to address the extent of this phenomenon in healthy preschool children of a developing country. Materials and Methods: We conducted a prospective study from April 2013 to March 2014 on 410 healthy 2-6 years old preschool children in Isfahan, Iran. Demographic medical data and nasal samples were collected from the participating children. Isolates were identified as S. aureus and MRSA based on microbiological and molecular tests, including the presence of eap and mecA genes. Results: The overall prevalence of S. aureus and CA-MRSA nasal carriage was 28% (115/410) and 6.1% (25/410), respectively. The identity of isolates was confirmed by molecular assay. The factors that were independently associated with nasal carriage of S. aureus were: Children crowding in day-care nurseries and income level of families. A total of 20/90 (22.2%) of methicillin-susceptible S. aureus and all 25 CA-MRSA displayed multiple drug resistance to 3–8 antibiotics. Conclusions: The current report reflects issues and concerns that the high rate of colonization by CA-MRSA in Iranian healthy children provides obliging evidence that MRSA have established a foothold in the community and are emerging as important health threatening pathogens. It is suggested that we need more effective infection control measures to prevent transmission of nasal CA-MRSA in healthy preschool children.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of infections. The changing epidemiology of MRSA became evident in the 1990s when CA-MRSA cases were first reported. Nasal carriage of CA-MRSA is associated with an increased risk for development of infections in various populations. Materials and Methods: Anterior nares culture for the presence of methicillin-susceptible Staphylococcus aureus (MSSA) and MRSA was taken from 345 children attending kindergartens, who didn't have any known risk factor for MRSA colonization. Also, children demographic variables were recorded. Identification of SA and community-acquired methicillin-resistant Staphylococcus aureus ( CA-MRSA) with standard microbiological test was performed. Finally, the susceptibility of isolated to various antibiotics determined. The data were analyzed with Whonet 5.6 software. Results: Of 345 children, 20 children (5.8%) were colonized with CA-MRSA, 86 children (24.9%) with MSSA and 239 cases (69.3%) didn't have SA colonization. The highest rate of MSSA and MRSA colonization was obtained at the age of 6 years. The frequency distribution of SA (MSSA and MRSA) colonization prevalence didn't have any significant differences based on age, gender and the admission time (P > 0.05); but it was significantly different in the urban areas (P < 0.001). The lowest resistance rate of CA-MRSA isolates, with a frequency of 10%, was detected with gentamicin, rifampin, and trimethoprim-sulfamethoxazole. Conclusions: In summary, CA-MRSA colonization was observed in child care centers remarkably. Therefore, by facing various infections due to SA especially in areas of low socio-economic status, it must be considered. Based on antibiogram test, empirical treatment with rifampin, gentamicin and ciprofloxacin is recommended during CA-MRSA infections.

Background: Nosocomial infections are one of the most important medical problems in developed and under developing countries which cause the spread of infections diseases in society. Pseudomonas aeroginosa is one of the most important causes of hospital infections, especially in wounds from operated patients. Increase in antibiotic-resistance of pseudomonas aeroginosa cause a lot of problems for patients and in some cases lead to septicemia and death of patients. The aim of this study is to isolate and determine the drug resistance pattern of indigenous pseudomonas leading to cutaneous infections of patients in Alzahra hospital. Methods: In this study 770 samples were obtained from cutaneous wounds of patients hospitalized in Azahra hospital. Biochemical tests were used for identification of Pseudomonas aeroginosa. Antibacterial susceptibility test for antibiotics amikacin, cephtazidin, ciprofloxacin, tasocin, imipinim was performed using disk diffusion (Kirby- Buer) methods. Findings: Among 770 patients, 56 patients (7.3%) showed cutaneous infection caused by pseudomonas aeroginosa. Antibiotic resistance pattern showed that 82. 14% samples were resistant to ceftriaxone and for amikacin 57.14%, ceftazidime 53.57%, ciprofloxacin 42.85%, tazocin 39.28%, imipenem 14.28% respectively. Conclusion: These results indicate the necessity of culturing and antibiogram tests before treatment of bacterial cutaneous infections. Antibiotic resistance- patterns can be very helpful in choosing the appropriate drug. Also in the first phase, it cold be considered for treatment of the disease. Key words: Nosocomial infections, Skin infection, Pseudomonas aeroginosa, Drug resistance, Antibiotic.

Background: Acinetobacter baumannii is one of the most important pathogens in hospital-acquired infections especially in intensive care units (ICUs). This opportunistic pathogen can be easily isolated from water, soil, and hospital facilities. A. baumannii as a nosocomial opportunistic pathogen is resistant to a wide range of antibiotics and responsible for multiple infections, including bacteremia, pneumonia, meningitis, urinary tract infections, and surgical wounds. The aim of this study was to determine frequency and resistance patterns of A. baumannii isolated in ICUs of Isfahan Hospitals. Materials and Methods: During 1 year period (2012-2013), 350 specimens were collected from ICUs of Isfahan hospitals. The isolates were characterized as A. baumannii by conventional phenotypic, biochemical tests and confirmed by PCR for OXA-51-like gene. Susceptibility of isolates was determined by standard disk diffusion method according to CLSI. Results : From total of 350 specimens, 43 isolates were A. baumannii. The antimicrobial patterns of isolates showed that 53.5% of isolates were resistant to amikacin, 83.7% to tetracyclin, 86% to ceftazidime, 90.7% to Trimethoprim sulfametoxazol, 93% to imipenem, cefepime, meropenem, ampicillin-sulbactam. All isolates were resistant to ciprofloxacin. Conclusion: This study showed a high resistance of A. baumannii to a wide range of antimicrobial agent. It is necessary to adopt appropriate strategies to control the spread of the bacteria in care unit centers and wards.

Background: In recent years, antibiotic resistance of Staphylococcus epidermidis to methicillin has significantly increased, making it essential to study resistance to methicillin, which is a determining factor in the appropriate treatment pattern. The purpose of this study was to identify methicillin-resistant genes in S. epidermidis strains using polymerase chain reaction (PCR) and to determine their mean minimum inhibitory concentration (MIC) to methicillin using E-test method. Materials and Methods: MIC was determined on 146 samples of S. epidermidis using E-test method. Moreover, all samples were tested for the presence of mecA gene using PCR. Results: PCR test showed 75.34% of the samples to contain mecA gene. Methicillin resistance test was performed using E-test on all the samples, which showed resistance in different dilutions. Conclusion: The frequency of mecA gene in S. epidermidis isolates was 75.34%. Among the various applied tests used for determining methicillin resistance, sensitivity and specificity of PCR were the highest and reached 100%. Sensitivity and specificity were found to be 95.3% and 94.7%, respectively, for phenotypic test (E-test) and 86.5% and 80.9%, respectively, for disk diffusion method. Based on the above results, it seems that resistance of S. epidermidis to methicillin is on the rise, and therefore more research is warranted.

Background: Staphylococcus aureus is a common human pathogen in community- and hospital-acquired infection, and its capsule is involved in pathogenesis. The predominance of 2 capsular polysaccharides types 5 and 8, on the surface of clinical isolates, led to the development of conjugate vaccine (Staph VAX) based on capsular polysacchrides types 5 and 8 conjugated to a carrier protein. The aim of this study was to determine the prevalence of capsular polysaccharides types 5 and 8 Staphylococcus aureus strains among isolates and their comparison with respect to methicillin resistance. Materials and Methods: We studied the capsular genotypes of 193 isolates that encompassed both hospital- and community-acquired infection in Al-Zahra Hospital of Isfahan city from 2008 to 2009. Cap5 and 8 genes were detected by PCR method. Methicillin resistance was determined by PCR (mecA) and disk diffusion methods as well. Result: In this population (193 cases), most of the clinical isolates (73%) expressed capsular polysaccharide type 5 (24%) and 8 (49%), whereas 27% were non-typeable. The prevalence of MRSA in type 8 was 67.9%, whereas MRSA isolates in the capsular genotype 5 were 22.2%. Conclusion: This study Staphylococcus aureus confirms that the prevalence of capsular polysaccharide types (5 and 8) are predominant, and Staphylococcus aureus type 8 is more resistant to methicillin compared to type 5.