Search

Clostridium difficile is a leading causative agent of hospital-acquired and community-acquired diarrhea in human. This study aims to characterize the predominant C. difficile strains, RT001 and 126, circulating in Iranian hospitals in relation to resistant phenotypes, the antibiotic resistance genes, and their genetic relatedness. A total number of 735 faecal specimens were collected from patients suspected of CDI in Tehran hospitals. Typing and subtyping of the strains were performed using CE-PCR ribotyping and MLVA, respectively, followed by PCR assays for ARGs and indicators of Tns. Minimum inhibitory concentrations (MICs) of five antibiotics were determined by MIC Test Strips. Among 65 strains recovered from CDI patients, RT001 (32.3%) and RT126 (9.2%) were found as the most frequent ribotypes, and 64 MLVA types were identified. Using MLVA, RT001 and RT126 were subtyped into 6 and 4 groups, respectively. The vanA, nim, tetM, gyrA, gyrB genes were detected in 24.6%, 0%, 89.2%, 95.3%, and 92.3% of the strains, respectively. The indicators of Tns including vanHAX, tndX, and int were found in 0%, 3% and 29.2% of the strains, respectively. The most common amino acid (AA) alterations of GyrA and GyrB were related to substitutions of Thr82 → Val and Ser366 → Val, respectively. Resistance rate to metronidazole, vancomycin, tetracycline, ciprofloxacin, and moxifloxacin was 81.5%, 30.7%, 85%, 79%, and 74%, respectively. This study, for the first time revealed the subtypes of circulating RT001 and RT126 in Iran. It is of importance that the majority of the strains belonging to RT001 were multidrug resistant (MDR). This study also pointed to the intra-hospital dissemination of the strains belonging to RT001 and RT126 for short and long periods, respectively, using MLVA. The most important resistance phenotypes observed in this study was vancomycin-resistant phenotypes. Resistance to metronidazole was also high and highlights the need to determine its resistance mechanisms in the future studies.

Probiotics could be considered as attractive candidates for preventing tumor growth through maintaining homeostasis. The aim of this study was to evaluate the inhibitory effect of a cocktail of five Lactobacillus species on human colorectal carcinoma cell line HT-29. The anti-proliferative and apoptotic effects of Lactobacilli cocktail were evaluated using MTT and flow cytometry tests, respectively. Quantitative real-time polymerase chain reaction (qPCR) was used to analyze the expression of several genes in the Notch (notch, hes1, msi1, and numb) and Wnt/β-catenin (CTNNB1 and CCND1) pathways, following the treatment of HT-29 cells with Lactobacilli cocktail. The treatment by Lactobacilli cocktail induced a significant anti-proliferative effect and late stage apoptosis among the cancer cells (p < 0.05). Compared to the untreated cells, Lactobacilli cocktail induced the down-regulation of notch, hes1, and msi1 genes and up-regulation of numb gene in the Notch pathway as well as the down-regulation of CTNNB1 and CCND1 genes in the Wnt/β-catenin pathway in a time-dependent manner (p < 0.05). CONCLUSION: Lactobacilli cocktail was shown to have beneficial anti-tumor effects on HT-29 cells by modulating the Notch and Wnt/β-catenin pathways; therefore, the use of Lactobacilli probiotics as nutritional supplements may prevent the incidence of colon cancer., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2019. Published by Elsevier Ltd.)

Large-scale genome-wide studies have revealed the role of several genes and their respective single-nucleotide polymorphisms (SNPs) in the pathophysiology of late-onset Alzheimer's disease (LOAD). Here, the frequencies of ABCA7 SNPs rs3764650 and rs4147929 and EphA1 SNP rs11771145 were assessed and compared in LOAD patients and healthy subjects. In a case-control study, 110 patients with LOAD (case) and 88 healthy unrelated age- and gender-matched individuals (control), both from Azeri descent, were enrolled. DNA was extracted from blood samples using the salting out method, and the genotyping was performed by RFLP-PCR for rs3764650, rs4147929, and rs11771145 polymorphisms. Electrophoresis was carried out on agarose gel. Sequencing was utilized for confirmation of the results. No differences were found in the frequencies of ABCA7 SNP rs3764650 and EphA1 SNP rs11771145 between healthy subjects and LOAD patients. However, a significant difference was revealed in the frequencies of AA (p = 0.042, OR = 0.150; 95%CI = 0.005-1.410) and GG (p = 0.009, OR = 1.716; 95%CI = 0.918-3.218) genotypes of ABCA7 SNP rs4147929 between the mentioned groups. This study showed that ABCA7 SNP rs4147929 might be a predisposing factor for LOAD. However, such an association was not found between ABCA7 SNP rs3764650 as well as EphA1 SNP rs11771145 and LOAD. These results must be confirmed in other ethnic groups.

In healthcare settings, contamination of environment with toxigenic and hypervirulent Clostridioides difficile strains is a serious concern. Here, we assessed whether patients with C. difficile have a role to play in the dissemination of C. difficile in our settings or other sources are implicated in its circulation. A total of 700 fecal specimens and 1435 environmental samples from surfaces, equipment and air of rooms occupied by patients suspected of C. difficile infection were taken from 4 tertiary hospitals in Tehran, Iran between April 2016 and August 2017. Antibiotic susceptibility testing and detection of resistance genes were performed for the environmental isolates. The clinical and environmental isolates of C. difficile were subjected to Pulsed Field Gel Electrophoresis (PFGE) analysis. Forty three (6.14%) and 2 (0.13%) isolates of C. difficile were recovered from the clinical and environmental samples, respectively. In the clinical settings, 2 patients were suspected of recurrent C. difficile infection. Thirty distinct pulsotypes were found among the C. difficile isolates including 28 singletons and 2 common types. One of the two environmental isolates was isolated from floor in the Medical ward, of pulsotype/ribotype/toxinotype PT10/New ribotype/toxinotype V, harbored cdtA/B and tcdC-A, and resistant to ciprofloxacin. The other one was isolated from air of a room in ICU, assigned to PT11/RT001/toxinotype 0, belonged to tcdC-sc3 genotypes and resistant to metronidazole. The environmental isolates did not generate amplicons in PCR assays targeting vanA and nim genes. This study provided evidence for dissemination of genetically diverse strains of C. difficile in hospitalized patients, presence of C. difficile in hospital air, existence of binary toxin positive/antibiotic-resistant isolate on the floor and intra-hospital dissemination of this pathogen., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Objectives: Clostridium difficile (C. difficile) is the main causative agent of antibiotic-associated diarrhoea (AAD) and pseudomembranous colitis. The accumulation of antimicrobial resistance in C. difficile strains can drive C. difficile infection (CDI) epidemiology. This study was undertaken to evaluate the antimicrobial resistance patterns of toxigenic C. difficile isolates cultured from diarrhoeal stool samples of hospitalised patients with suspected CDI in three tertiary care hospitals in Tehran, Iran., Methods: Two hundred and fifty diarrhoeal stool samples were investigated by toxigenic culture using cycloserine-cefoxitin-fructose agar and the VERO cell line. Antimicrobial susceptibility to metronidazole, vancomycin, clindamycin, tetracycline, and moxifloxacin was performed by disk diffusion and Etest methods on Brucella Blood Agar supplemented with hemin and vitamin K., Results: Thirty-five stool samples (14.0%) proved positive using C. difficile toxigenic culture. According to Clinical and Laboratory Standards Institute breakpoints, the following resistance was identified in C. difficile isolates: metronidazole (2 of 35); moxifloxacin (7 of 35); clindamycin (18 of 35); and tetracycline (5 of 35). Using European Committee on Antimicrobial Susceptibility Testing breakpoints, three of 35 isolates showed reduced-susceptibility for vancomycin and 14 of 35 for metronidazole. In addition, the results showed a good correlation between the inhibition zone diameter (disk diffusion) and MIC values (Etest); Pearson correlation coefficient 0.7400.95 (P< 0.001)., Conclusions: Multidrug resistance was observed in Iranian clinical toxigenic C. difficile isolates, including reduced susceptibility to first-line CDI treatment drugs. In addition, disk diffusion can be used as a cost-effective option for the antimicrobial susceptibility testing of C. difficile isolates., (Copyright © 2019 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.)

Background: Infections caused by bacteria are a foremost cause of morbidity and mortality in the world. The common strategy of treating bacterial infections is by local or systemic administration of antimicrobial agents. Currently, the increasing antibiotic resistance is a serious and global problem. Since the most important agent for infection is bacteria attaching to host cells, hence, new techniques and attractive approaches that interfere with the ability of the bacteria to adhere to tissues of the host or detach them from the tissues at the early stages of infection are good therapeutic strategies., Methods: All available national and international databanks were searched using the search keywords. Here, we review various approaches to anti-adhesion therapy, including use of receptor and adhesion analogs, dietary constituents, sublethal concentrations of antibiotics, and adhesion-based vaccines., Results: Altogether, the findings suggest that interference with bacterial adhesion serves as a new means to fight infectious diseases., Conclusion: Anti-adhesion-based therapies can be effective in prevention and treatment of bacterial infections, but further work is needed to elucidate underlying mechanisms.

The purpose of the present study was to isolate Lactobacillus bacteria from mother's milk and to assess their probiotic potential. Sixty breast milk samples were collected from the volunteered mothers aged from 19 to 35 and from rural areas of Lorestan and Markazi Provinces, Iran. At first, 970 bacill-shaped bacterial colonies were isolated from these samples and stored in proper condition. Two hundred isolates were randomly selected and investigated for their ability to tolerate acidic condition and to tolerate bile salt as well. Only 33 isolates could withstand the exposure to low pH and bile salt. The isolates were identified using PCR primer specific to Lactobacillus and it was demonstrated that eighteen of thirty-three isolates were belonged to the Lactobacillus. Among the isolates, 16 and 2 of them were Lactobacillus reuteri and L. gasseri, respectively. In addition, the antibiotic resistance of the isolates was determined using disc diffusion method and all of the isolates were shown to be sensitive to eight out of the twelve investigated antibiotics. Moreover, the antagonistic effect of the isolates was inspected on ten indicator pathogens. Interestingly, all of the pathogenic bacteria were inhibited by Lactobacillus isolates. In addition, to partially understand the nature of inhibition mechanism, well diffusion deployed for two randomly-selected indicator bacteria and the resulting halos of three isolates were statistically significant compared to other lactobacillus (p < 0.05). Subsequently, bacteriocin genes (plnS, Laf, gasA) were identified by PCR among the isolates. The results showed that only 2 isolates possessed the gasA gene which were in accordance with well diffusion test. Consequently, eighteen Lactobacillus isolated from breast milk samples which all of them were able to tolerate low pH and bile salt. Similarly, all of the Lactobacillus isolates were proved to inhibit the growth of pathogen strains and two of them possess a bacteriocin-related gene., (Copyright © 2018. Published by Elsevier Ltd.)

Despite the low expensive and effective four-drug treatment regimen (isoniazid, rifampicin, pyrazinamide and ethambutol) was introduced 40 years ago, TB continues to cause considerable morbidity and mortality worldwide. In 2015, the WHO estimated a total of 10.4 million new tuberculosis (TB) cases worldwide. Currently, the increased number of multidrug-resistant (MDR-TB), extensively-drug resistant (XDR-TB) and in some recent reports, totally drug-resistant TB (TDR-TB) cases raises concerns about this disease. MDR-TB and XDR-TB have lower cure rates and higher mortality levels due to treatment problems. Novel drugs and regimens for all forms of TB have emerged in recent years. Moreover, scientific interest has recently increased in the field of host-directed therapies (HDTs) in order to identify new treatments for MDR-TB. In this review, we offer an update on the discovery of new drugs for TB therapy with a glance at molecular mechanisms leading to drug resistance in Mycobacterium tuberculosis., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Objectives: To elucidate the association between asymptomatic infections caused by Mycoplasma genitalium and male infertility, and evaluate the role of antibiotic therapy in treatment of this failure., Methods: A total of 165 infertile males having abnormal semen parameters (study group) and 165 healthy fertile men (control group) were included. Semen samples were taken from all participants and after analyzing for semen parameters, undergone real-time PCR, microbial culture, and reactive oxygen species (ROS), as well as total antioxidant capacity (TAC) assays. Infected individuals of study group were treated with antibiotic. One month after the treatment completion, second semen samples were taken and subjected to all the tests mentioned. The data were analyzed using SPSS statistical software, version 22.0., Results: The frequency of M. genitalium was significantly higher in the infertile men compared with the fertile ones (9.7% vs. 1.2%; p = 0.001). Mean cycle threshold (C t ) value was lower in infected infertile than infected fertile men (p < 0.001). All semen parameters, except volume, pH, and viscosity, were improved (p < 0.05), most of which reached their normal range; leukocytes in seminal fluid decreased (p = 0.02), the level of TAC was elevated (p = 0.002), and ROS level as well as ROS/TAC ratio reduced after antibiotic treatment (p = 0.03). Wives of seven infected infertile men (43.8%) became pregnant 4 months after the treatment completion., Conclusions: Asymptomatic infection caused by M. genitalium is correlated with male infertility and antibiotic therapy can improve the semen quality and be used to treat male infertility.

Lactobacillus species play a major role in gastrointestinal (GI) tract function, intestinal microbiota balance, and the immune system activity by exerting a strong activity against many intestinal pathogens. The aim of this study was to isolate Lactobacillus species from fecal samples, investigate their antimicrobial properties, and characterize their bacteriocin encoding genes. 48 fecal samples were grown in MRS broth and then MRS agar. The colonies grown in MRS agar were selected and identified by PCR. 72 Lactobacillus species were obtained from 434 lactic acid bacteria (LAB) strains. Approximately 40% of all Lactobacillus isolates had antimicrobial activity against one or more microorganisms and 17.4% of them were active against all four indicator bacteria. The frequency of bacteriocin encoding genes were 5 (6.9%), 3 (4.1%) and 5 (6.9%) for Gassericin A, Plantaricin S and Laf operon, respectively. pH alteration had no effect on antibacterial activity, but in the alkaline range these activities were reduced and the strains showed the highest antibacterial activity after 48 h incubation. These data indicate that the majority of isolates were susceptible to GI tract or belonged to other bacterial forms such as viable but nonculturable (VBNC). The detection of bacteriocin encoding genes in about only 6% of all Lactobacillus isolates seems to be due to the existence of many other bacteriocin encoding genes in Lactobacillus species which were not tested. Further study of the bacteriocin gene clusters, types, subtypes and the probiotic effect of these strains will contribute to a better characterization of these isolates., Competing Interests: The authors declared no conflict of interest.

Antibacterial activity of Bifidobacterium species has been considered as an important probiotic property for development of human gut immunity. This study was conducted to assess the genotypes and antibacterial activities of the native Bifidobacterium isolates obtained from the human's breast milk and the feces of their paired infants. Fifty-six samples from twenty-eight mothers' milk and paired infants feces were collected and cultured. Suspicious colonies were picked up and confirmed by phenotypic and molecular identifications. Randomly amplified polymorphic DNA (RAPD-PCR) and antibacterial activity were carried out. Amongst 56 samples, 41 different Bifidobacterium species including 12 B. breve, 14 B. longum, and 15 B. bifidum were isolated. Out of which, 12 isolates including B. longum (6), B. breve (4) and B. bifidum (2) were shared between six mother-infant pairs. Only three strains of B. longum showed 100% similarity in their RAPD-PCR. No significant difference was observed in the antibacterial activity of the Bifidobacterium isolates, with the same or different RAPD-PCR profile, against the enteric bacteria. Overall, 29% of the Bifidobacteria species isolated from the mothers milk and their paired infants feces were shared. All species of Bifidobacteria showed the universal role of antipathogens activities irrespective of the host and the isolation site., (Copyright © 2017. Published by Elsevier Ltd.)

It is known that type 2 diabetes (T2D) in humans could be linked to the composition of gut microbiota. The aim of this study was to evaluate three faecal bacterial species, including Bacteroides fragilis, Bifidobacterium longum and Faecalibacterium prausnitzii in patients with T2D. This case control study included 18 patients with T2D and 18 matched persons without diabetes. The concentrations of B. fragilis, B. longum and F. prausnitzii were determined by quantitative Real-Time PCR. Quantitative PCR analysis revealed that the gut bacterial composition in patients with T2D was partially different from that in the healthy individuals. Faecalibacterium prausnitzii was significantly lower in patients with T2D (P-value = 0.038). Bacteroides fragilis was under-represented in the microbiota of the group with diabetes, but its difference between two groups was not significant (P-value = 0.38). No difference was observed for B. longum community between the both groups (P-value = 0.99). Characterization of specific species of intestinal microbiota shows some compositional changes in patients with T2D. The results may be valuable for developing strategies to control type 2 diabetes by modifying the intestinal microbiota. Long-term studies with emphasis on other bacterial groups are suggested to clarify the association of T2D with gut microbiota., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Objective: To elucidate the association between asymptomatic infections caused by Mycoplasma hominis and male infertility and to evaluate the role of antibiotic therapy in the treatment of this failure., Materials and Methods: A total of 165 infertile men having abnormal semen parameters (study group) as well as 165 healthy fertile men (control group) were included in this study. Semen samples were taken from all participants and, after analyzing for semen parameters, real-time polymerase chain reaction, microbial culture, and reactive oxygen species (ROS) as well as total antioxidant capacity (TAC) assays were performed. Infected individuals of the study group were treated with antibiotic. One month after the treatment completion, second semen samples were taken and all the tests mentioned were performed. The data were analyzed using SPSS statistical software, version 22.0., Results: The frequency of M. hominis was significantly higher in the infertile men compared with the fertile ones (14.5% vs 3.6%, P = .001). The mean cycle threshold (C t ) value was lower in infected infertile men than in infected fertile men (P < .001). All semen parameters, except volume, pH, and viscosity, were improved (P < .05), most of which reached their normal range; leukocytes in seminal fluid were eliminated (P = .04); the level of TAC elevated (P < .001); and the ROS level as well as the ROS-to-TAC ratio reduced after antibiotic treatment (P = .02). Moreover, wives of 14 infected infertile men (58.3%) became pregnant 4 months after the treatment completion., Conclusion: Our data suggest that asymptomatic infection caused by M. hominis is correlated with male infertility and antibiotic therapy can improve the semen quality and fairly treat the male infertility., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Enterococci have a widespread attendance in the circumference and belongs to the enteric commensal microbiota. Most of them produce the antimicrobial compounds and have an inhibition effect on pathogenic microorganisms. The objective of this study was to characterize the enterococcal strains isolated from human normal flora and assess their antibacterial activity. Enterococcal isolates were obtained from the feces of eighteen healthy humans. All enterococcal species were identified by biochemical and species-specific polymerase chain reaction (PCR). These isolates were investigated further to examine their ability to inhibit growth of Salmonella typhi, Shigella flexneri and Escherichia coli by well diffusion assay. Furthermore, antibiotic susceptibility test was performed and genetic relatedness of all isolates was evaluated by Pulse Field Gel Electrophoresis (PFGE). In all, 432 isolates were obtained from fecal samples. All of the isolates identified as Enterococcus faecium by biochemical and molecular (PCR) methods. Using repetitive element palindromic (REP)-PCR method 54 patterns have been obtained and were selected for further evaluation. The results indicated that 66%, 38% and 24% of our isolates had antimicrobial effect against S. typhi, S flexneri and enteroaggregative Escherichia coli (EAEC), respectively. On the other hand, there was no significant inhibition effect against enteropathogenic E. coli (EPEC) and enterotoxigenic E. coli (ETEC). All isolates were sensitive to vancomycin, teicoplanin, linezolid, ampicillin, chloramphenicol and gentamicin. On the other hand, the resistance rates for erythromycin, tetracycline and ciprofloxacin were 20%, 22%, and 1.8% respectively. In addition, the analysis of PFGE showed forty patterns with eight (40.7%) common types (CT) and thirty two (59.2%) single types (ST). Among eight common types, only one common type (CT5) had similar antimicrobial effect. These results suggested that enterococcal isolates obtained from human normal flora have potential antibacterial effect against S. typhi, S. flexneri and E. coli., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Acinetobacter baumannii is one of the important causes of nosocomial infection especially in burn patients. So, carbapenemase producing strains can make serious therapeutic problems. Molecular epidemiology studies play key role in decreasing the incidence of carbapenemase producing strains., Methods: In this study, 50 carbapenem resistant A. baumannii isolates from burn patients were collected. Antibiotic susceptibility testing and PCR assay was performed for detection of blaVIM, blaIMP, blaOXA-23,blaOXA-48,blaNDM-1, blaSPM-1, blaOxa-51 and blaKPC genes. Molecular typing for carbapenemase producing strains were performed by PFGE and MLVA., Results: According to the results of antibiotic susceptibility tests all of strains were XDR and 46 (92%) harbored carbapenemase genes. PFGE and MLVA results showed the presence of 11 and 5 dominant clonal types respectively., Conclusion: The results of this study were showed the presence of certain clonal groups in two different wards of hospital indicating the spread of carbapenemase producing A. baumannii. On the other hand, the results showed the more discriminating power for PFGE., (Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.)

The emergence of multidrug resistance (MDR) and extensively drug resistance (XDR) in Acinetobacter baumannii has made an important challenge in the treatment of infections caused by this organism. The ability of carbapenemase production is one of the main mechanisms for the emergence of MDR and/or XDR in A. baumannii. The aim of this study was to detect carbapenemase producer A. baumannii. In this study, 65 imipenem resistant A. baumannii were collected from burned patients. Biochemical identification, antibiotic susceptibility test and multiplex polymerase chain reactions for the detection of carbapenemases genes were performed. The results showed that all strains carried bla OXA-51. 83%, 12.5% and 9.23% strains harbored bla OXA-23, bla VIM and bla KPC genes, respectively. None of the isolates carried bla IMP, bla OXA-48, blaNDM-1 and bla SPM-1 genes. The results of this study indicate the emergence of Klebsiella pneumoniae Carbapenemase (KPC) in A. baumannii causing nosocomial infections in burned patients which can be important for hospital infection prevention systems in Iran.

Enterococci are Gram positive and catalase- negative cocci that are found in the gastrointestinal tract of mammals and birds, and are readily isolated from soil, surface and waters. The aim of this study was to discriminate between Enterococcus isolates based on repetitive element sequence based -PCR (Rep-PCR) with the BOXA2R primer and their antibiotics profile. Enterococci isolates were obtained from 180 fecal samples. The isolates were identified by biochemical reaction and specific identification was confirmed by PCR with species specific primers. All isolates were subjected to Rep typing and antimicrobial susceptibility tests. Rep-PCR analysis of 180 isolates revealed 93 REP types with forty-five single types (ST1 to ST45) and forty-eight common types (CT1 to 48). Antibiotic susceptibility tests exhibited that 53 (29.4%), 43 (23.8%), 11 (6.1%) and 9 (5%) were resistant to erythromycin, tetracycline, gentamicin and ciprofloxacin respectively but among the isolates, sixteen were multi drug resistant (MDR). These MDR isolates showed 11 Rep types with seven single types and four common types. In addition, 81.2% of MDR isolates were from male subjects and the average age of these persons was more than fifty years. This study showed that 56.2% of MDR isolates were homogeneous with 95 % similarity, and high rate of resistance to tetracycline and erythromycin (81.2%) were observed in these isolates. The concern about these normal flora isolates are the pathogenic potential of these bacteria through the horizontal transfer of antibiotic resistance and virulence genes.

Background and Objective: The production of carbapenemases especially Klebsiella pneumoniae carbapenemase (KPC) is the most important mechanism of enzymatic resistance in isolated Enterobacteriaceae such as K. pneumoniae . The purpose of this study was detected of the carbapenemase producer K. pneumoniae strains with phenotypic and genotypic methods., Method: Out of 800 strains, 270 K. pneumoniae strains (33.7%), were obtained. Antibiotic susceptibility test was performed by disk diffusion method in accordance with CLSI guidelines. Carbapenem resistant strains were identified by the Modified Hodge Test based on CLSI instruction and PCR for surveying the presence of bla -KPC gene., Results: A total 270 K. pneumoniae strains were collected. Antibiotic susceptibility test results showed the highest and lowest resistance was related to piperacillin (60.6%) and carbapenems (14.6%) respectively. 80.5% (33 of 41) isolates were positive by MHT, but all of them (100%) were negative for amplification of the bla -KPC gene in the PCR method., Conclusion: The MHT was an appropriate method for approving carbapenemase production. Moreover, a laboratory could accept the carbapenemase production with PCR method for the bla-KPC gene, which has the additional profit of validating which KPC is present.

Background: Resistance to carbapenems is developing around the world and can cause many problems for treatment of patients. Production of metallo-beta-lactamase (MBL) is one of the main mechanism for this type of resistance. So, detection of MBL-producer microorganisms can prevent the spread of this type of resistance., Materials and Methods: In this study 94 Acinetobacter spp. were investigated. Resistance to imipenem was conducted after purification and identification. Combination disc (CD) and Double Disc Synergy Test (DDST) were performed for phenotypic detection of MBL and the molecular PCR method was done for vim-1, vim-2, imp-1 and OXA-23 genes., Results: According to TSI, SIM and oxidation-fermentation (OF) test and PCR assay 93 Acinetobacter baumannii and one strain Acinetobacter lwoffii were identified. 85% of them were resistant to imipenem. 34% of them have a positive combination disc test (CD) while Double Disc Synergy Test (DDST) was negative for all of them. The vim-1, vim-2 and imp-1 genes were not detected in PCR molecular method, however in 74% of strains with positive results in combination disc, were positive for the OXA-23 gene after PCR test. This study shows that the blaOXA-23 resistance determinant may become an emerging therapeutic problem., Discussion: According to the results, it seems that combination disc does not have enough specificity for detection of MBL-producer Acinetobacter and using Double Disc Synergy Test (DDST) can be more convenient.

Background: Methicillin is the drug of choice to treat infections caused by resistant strains of Staphylococcus aureus. However, methicillin-resistant S. aureus (MRSA) is now becoming endemic in many hospitals worldwide and is the cause of nosocomial outbreaks., Methods: To assess clonality and dissemination of MRSA strains in the hospitals of Tehran, a total of 60 MRSA strains were isolated from hospitalized patients (n=44) and hospital equipment and environment (n=16) of three metropolitan hospitals in Tehran between July 2009 and March 2010. These strains were subjected to antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE), and biochemical fingerprinting using the PhPlate system., Results: Results showed the presence of between one and three dominant clonal groups within each hospital, with most equipment and environmental strains being identical to the dominant clones of hospitalized patient strains. The rate of resistance of these strains to the 13 antibiotics tested ranging from 2% to 100%, with resistance being highest for penicillin, ciprofloxacin, and tetracycline (>98% of the isolates). Comparison of the strains isolated from the three hospitals using a combination of PFGE and PhP types showed the presence of 11 clonal groups of MRSA among these hospitals; of these, three common clonal groups also had identical antibiotic resistance patterns and were found in more than one hospital., Conclusions: These data suggest dissemination of a few dominant clonal groups of MRSA strains in hospitals in Tehran, with high level resistance to other commonly used antibiotics., (Copyright © 2013 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Background: Vancomycin (glycopeptide)-resistant enterococci (VRE or GRE) can cause serious problems for hospitalized patients due to the limited options for treatment of VRE infections. As infection with VRE increases in hospitals, further knowledge about vancomycin resistant genes is needed., Methods: Isolates of Enterococcus spp. were collected from hospitalized patients in Tehran (Iran) during 2006. Detailed molecular analysis was performed for vancomycin resistance genotype and vanHAX using conventional PCR and PCR- RFLP (restriction fragment length polymorphism), respectively., Results: out of 830 enterococci spp., 48 VRE isolates (5.8 percent) were obtained. All of VRE isolates carried vanA gene. DdeI digestion of vanHAX element showed the presence of point mutation at 8234 position., Conclusion: This study indicates that vanA is a predominant genotype in Iranian isolates. In addition, PCR-RFLP analysis revealed the presence of two types of vanHAX element in vanA harboring transposons.

Background: Enterococci are important because of their role as the leading cause of nosocomial infections which have a significant role in the dissemination and persistence of antimicrobial resistance genes., Methods: In this study, we determined the distribution of enterococcal species in the sewage treatment plants in Iran. Furthermore, we improved a rapid and specific PCR method using primers (sodA and ddl genes) for identification of enterococci spp., Results and Conclusion: A total number of 712 enterococci spp. were isolated and the results showed that 56%, 24%, 12%, 4%, 2%, 1% and 1% isolates were E. faecium, E. hirae, E. faecalis, E. gallinarum, E. casseliflavus, E. mundtii and other enterococcal spp., respectively. The use of species-specific PCR was in agreement with the biochemical tests. Furthermore, multiplex PCR was developed to study the presence of vancomycin resistant genes in E. faecium or E. faecalis. The multiplex PCR appeared to be a useful, rapid and specific method for detecting and discriminating genotypes for vancomycin-resistant Enterococcus.