Determination of carbapenem resistance mechanism in clinical isolates of Pseudomonas aeruginosa isolated from burn patients, in Tehran, Iran

Carbapenems are the most important therapeutic options that effect against serious infections caused by multidrug resistant Pseudomonas aeruginosa [MDR-PA] isolates. Carbapenems resistant isolates of P. aeruginosa are increasing worldwide. The aim of this study was to determine the carbapenem resistance mechanisms in clinical P. aeruginosa isolates from burn patients, in Tehran, Iran. A total of 53 non-duplicated isolates of carbapenem-resistant P. aeruginosa were collected from burn patients. The presence of carbapenemase genes were determined by PCR. AmpC overproducer isolates were detected by phenotypic method. The mutation and transcription level of oprD were determined by PCR-sequencing and quantitative Real-time PCR [RT-PCR], respectively. Twenty-seven [50.9%] isolates were positive for carbapenemase [bla[vm] = 25 and bla[mp] = 2] and showed high-level resistance to imipenem and merope-nem. Twenty-eight isolates were AmpC overproducers. All isolates had a mutation in the oprD gene and down-regulation of oprD was found in 56.6% of MDR-PA isolates. Although the presence of carbapenemase is the common mechanism of resistant to carbapenem, but carbapenem resistance was found by oprD mutation-driven and the AmpC overproducing isolates in Tehran, Iran

Molecular investigation of Staphylococcus aureus isolated from the patients, personnel, air and environment of an ICU in a hospital in Tehran

The aim of this study was to determine the prevalence and characteristics of Staphylococcus aureus isolates from the patients, staff, air and environments of an ICU in a hospital in Tehran. During this study, 37 S. aureus isolates were collected and analyzed via the spa typing method. Of the 37 S. aureus isolates, 35 [94%] were methicillin resistant [MRSA], 28 [76%] were identified as SCCmec types III or IIIA, four [10%] were identified as SCCmec types I or IA and three [8%] were identified a SCCmec type IV. All of the MRSA isolates were resistant to oxacillin and contained mecA. The isolates were all spa typed and found to comprise 11 spa types, including t7688, t7689, and t7789, which have not previously been reported. The spa type t7688 was isolated from the hands of two ICU personnel. The spa type t7689 was observed among five isolates from the air and the environment. The spa type t7789 was observed among three isolates from the patients, ventilators and the air. The majority of the isolates [43%] belonged to spa types t030 and t037. Our results revealed that MRSA strains that were isolated from the air, the environment of the ICU and the patients who were colonized or infected with MRSA often exhibited the same spa and SCCmec types. These results also reveal that the isolates from the patients and environment were usually indistinguishable

In silico analysis for identifying potential vaccine candidates against Staphylococcus aureus

PURPOSE: Staphylococcus aureus is one of the most important causes of nosocomial and community-acquired infections. The increasing incidence of multiple antibiotic-resistant S. aureus strains and the emergence of vancomycin resistant S. aureus strains have placed renewed interest on alternative means of prevention and control of infection. S. aureus produces a variety of virulence factors, so a multi-subunit vaccine will be more successful for preventing S. aureus infections than a mono-subunit vaccine. MATERIALS AND METHODS: We selected three important virulence factors of S. aureus, clumping factor A (ClfA), iron-regulated surface determinant (IsdB), and gamma hemolysin (Hlg) that are potential candidates for vaccine development. We designed synthetic genes encoding the clfA, isdB, and hlg and used bioinformatics tools to predict structure of the synthetic construct and its stabilities. VaxiJen analysis of the protein showed a high antigenicity. Linear and conformational B-cell epitopes were identified. RESULTS: The proteins encoded by these genes were useful as vaccine candidates against S. aureus infections. CONCLUSION: In silico tools are highly suited to study, design, and evaluate vaccine strategies.

Echinococcosis/hydatidosis in Ilam province, western Iran

Hydatidosis is a zoonotic disease of global prevalence. It causes considerable health problems and economic losses throughout the world, including Iran. The objective of this study was to assess the current status of echinococco-sis/hydatidosis in the province of Ilam [western Iran]. From April to September 2011, 65 stray dogs were collected from urban and rural areas of Ilam City. Parasites were isolated from the dogs and stained with carmine. A taxonomic study was carried out by measuring different parts of hel-minths. Meat inspection documents from slaughterhouses in Ilam were used to assess the prevalence of hydatidosis during a 3-year period in sheep, cattle, and goats. ELISA test was used to detect the presence of antibodies to hydatidosis in human sera. Clinical records from 2000 to 2010 of either treated or diagnosed patients from public hospitals of this province were reviewed. The prevalence of Echinococcus granulosus infection in stray dogs was 9%. A total of 81,726 animals were assessed for hydatidosis; 2.94% [2403 cases] had liver hydatidosis and 2.34% [1918 cases] had lung hydatidosis. Within a 10-year period, 140 patients [91 females and 49 males] were treated for hydatidosis. Of 1200 human sera, 2.25% [27 patients] were seropositive for hydatidosis. Hydatidosis is endemic in Ilam Province especially in rural area. The health and economic losses caused by the disease are significant; thus, our efforts need to be focused on the control of this disease

In vitro comparison of the effectiveness of Chiorhexidine and two calcium hydroxide formulations on Enterococcus faecalis

The aim of this in vitro study was to compare the effectiveness of three intracanal medicaments in disinfecting the root canal and dentin of experimentally infected human teeth with Enterococcus faecalis [EF]. One hundred extracted human single-rooted teeth were used. After root canal preparation, teeth were mounted in epoxy resin. Following sterilization, the teeth were infected for 28 days with EF. Then root canals were filled with one of three different disinfectants: viscous 2% Chlorhexidine [CHX], calcium hydroxide paste [CH] or a mixture of CH and CHX [n=30 in each group]. Antimicrobial assessments were performed at 1, 3 and 7 days [n=10 in each time period]. Microbial samples were obtained from root canals before and after the experiment. Also dentin samples were examined. The data was analyzed using Two- Way ANOVA test. The findings showed that there was no difference between experimental groups at different time periods. The mixture of CH/CHX in 7 days was able to eliminate EF completely from root canal system. The most elimination of EF was from dentinal tubules. According to the results of this in vitro study, viscous 2% CHX, mixture of CH with distilled water and 2% CHX are all effective disinfectants

Emergence of high-level vancomycin-resistant Staphylococcus aureus in the Imam Khomeini hospital in Tehran

The objective of the study was to investigate the prevalence of vancomycin-resistant Staphylococcus aureus [VRSA]. Three hundred and fifty-six S. aureus isolates from the Imam Khomeini hospital in Tehran, Iran, were evaluated for methicillin and decreased vancomycin susceptibility by the microbroth dilution method. The mecA, vanAand vanB genes were targeted by polymerase chain reaction. Of the 356 isolates, 149 [41.85%] S. aureus strains were resistant to methicillin. Two strains of methicillin-resistant S. aureus were VRSA strains. One isolate, Teaching Hospital-1 [TEH-1], had a vancomycin minimum inhibitory concentration [MIC] of 64 micro g/ml and was susceptible to teicoplanin while the other isolate [TEH-2] had a vancomycin and teicoplanin MIC of 512 and > 256 mg/ml, respectively, and was positive for the vanA gene. This report shows that the emergence of VRSA in Iran warrants active microbiological surveillance and careful monitoring of vancomycin therapy