Emergence of plasmid-mediated quinolone-resistant determinants in Klebsiella pneumoniae isolates from Tehran and Qazvin provinces, Iran.

BACKGROUND: Plasmid-mediated quinolone resistance is an increasing clinical concern, globally. The major objective of the present study was to identify the qnr-encoding genes among the quinolone non-susceptible K. pneumoniae isolates obtained from two provinces in Iran. METHODS: A total of 200 K. pneumoniae isolates were obtained from hospitals of Qazvin and Tehran, Iran. The identification of bacterial isolates was carried out by standard laboratory methods and API 20E strips. Susceptibility to quinolone compounds were examined by standard Kirby-Bauer disk diffusion method according to the CLSI guideline. PCR and sequencing were employed to detect qnrA, qnrB and qnrS-encoding genes. RESULTS: Of 200 K. pneumoniae isolates, 124 (62%) were nonsusceptible to quinolone compounds among those 66 (53.2%) and 58 (46.8%) isolates showed high and low-level quinolone resistance rates, respectively. Out of 124 quinolone non-susceptible isolates, qnr-encoding genes were present in 49 (39.5%) isolates with qnrB1 (30.6%) as the most dominant gene followed by qnrB4 (9.7%), and qnrS1 (1.6%) either alone or in combination. CONCLUSIONS: This study, for the first time, revealed the high appearance of qnrB1, qnrS1 and qnrB4 genes among the clinical isolates of K. pneumoniae in Iran. Therefore, the application of proper infection control measures and well-established antibiotic administration guideline should be strictly considered within our medical centers.

Leprosy elimination campaign in Qazvin province, Islamic Republic of Iran (2006-07).

Multi-drug therapy (MDT) and Leprosy Elimination Campaigns (LEC) are the major strategies for eliminating leprosy. We report the results of a LEC conducted in 2006 in Qazvin. A total of 1987 individuals (1379 household contacts of 319 registered leprosy patients and 608 people from 3 endemic villages with a high prevalence of leprosy) were examined for detection of new cases of leprosy. All new cases were given MDT and were reviewed after a year. There were 256 suspected cases of leprosy, 13 of whom were confirmed as new cases (7 were classified as multibacillary leprosy). None had visible deformity nor was < 20 years old. All patients completed the recommended MDT course. The few cases detected suggest that in low prevalence areas, a long-term approach of integrated leprosy services and disability management may be more appropriate than LEC as a leprosy elimination strategy.

Leprosy elimination campaign in Qazvin province, Islamic Republic of Iran [2006-07]

Multi-drug therapy [MDT] and Leprosy Elimination Campaigns [LEC] are the major strategies for eliminating leprosy. We report the results of a LEC conducted in 2006 in Qazvin. A total of 1987 individuals [1379 household contacts of 319 registered leprosy patients and 608 people from 3 endemic villages with a high prevalence of leprosy] were examined for detection of new cases of leprosy. All new cases were given MDT and were reviewed after a year. There were 256 suspected cases of leprosy, 13 of whom were confirmed as new cases [7 were classified as multibacillary leprosy]. None had visible deformity nor was < 20 years old. All patients completed the recommended MDT course. The few cases detected suggest that in low prevalence areas, a long-term approach of integrated leprosy services and disability management may be more appropriate than LEC as a leprosy elimination strategy

Dual effects of aliphatic carboxylic acids on cresolase and catecholase reactions of mushroom tyrosinase.

Catecholase and cresolase activities of mushroom tyrosinase (MT) were studied in presence of some n-alkyl carboxylic acid derivatives. Catecholase activity of MT achieved its optimal activity in presence of 1.0, 1.25, 2.0, 2.2 and 3.2 mM of pyruvic acid, acrylic acid, propanoic acid, 2-oxo-butanoic acid, and 2-oxo-octanoic acid, respectively. Contrarily, the cresolase activity of MT was inhibited by all type of the above acids. Propanoic acid caused an uncompetitive mode of inhibition (K(i)=0.14 mM), however, the pyruvic, acrylic, 2-oxo-butanoic and 2-oxo-octanoic acids showed a competitive manner of inhibition with the inhibition constants (K(i)) of 0.36, 0.6, 3.6 and 4.5 mM, respectively. So, it seems that, there is a physical difference in the docking of mono- and o-diphenols to the tyrosinase active site. This difference could be an essential determinant for the course of the catalytic cycle. Monophenols are proposed to bind only the oxyform of the tyrosinase. It is likely that the binding of acids occurs through their carboxylate group with one copper ion of the binuclear site. Thus, they could completely block the cresolase reaction, by preventing monophenol binding to the enzyme. From an allosteric point of view, n-alkyl acids may be involved in activation of MT catecholase reactions.

The effect of ceramic and porous fillers on the mechanical properties of experimental dental composites.

OBJECTIVES: The purpose of this study was to investigate the effect of ceramic fillers (containing leucite crystals) and their porosity on the mechanical properties of a new experimental dental composite in order to compare with the properties of composites containing conventional glass fillers. METHODS: In this study, experimental composites were prepared by mixing the silane-treated fillers with monomers. Experimental composites were divided into four groups according to their filler type, amount and porosity. The monomers were composed of 70% Bis-GMA and 30% TEGDMA by weight for all groups. Glass and leucite-containing-ceramic were prepared as different filler types. In order to make fillers porous, leucite-containing-ceramic fillers were treated with HF acid. Camphorquinone and DMAEMA were used as photo initiator system. Post-curing was done for all groups before mechanical testing. Degree of Conversion of composites was measured using FTIR spectroscopy. The diametral tensile strength (DTS), flexural strength and flexural modulus were measured and compared among the groups. RESULTS: The results showed that the stronger and more porous filler has a positive effect on flexural strength. Porosity of filler increased flexural strength significantly. No significant difference was found in DTS tests among the groups. Flexural modulus was affected and increased by using ceramic fillers. The type of the filler affected the DC of the composite and DC increased by post-curing. SIGNIFICANCE: Flexural strength is one of the most important properties of restorative dental materials. Higher flexural strength can be achieved by stronger and more porous fillers. Investigation into the effect of filler on dental material properties would be beneficial in the development of restorative dental material.

The inhibitory action of Mycobacterium ulcerans soluble factor on monocyte/T cell cytokine production and NF-kappa B function.

Buruli ulcer is a chronic and progressive necrotizing ulcer for which there is no medical treatment. Historically, a soluble toxin (factor) derived from the causative Mycobacterium ulcerans was found to induce the massive necrosis of skin and s.c. tissue seen in this condition. However, the persistence of the disease is thought to be caused by a lack of any immune response. We therefore investigated whether the factor was related to immunosuppression. A protocol to partially purify the factor was developed, and its effects on immune competent cells were tested. The factor produced >95% inhibition of LPS-induced release of TNF and IL-10 from human monocytes and caused a loss of adherence of these cells without cell death. The factor also blocked the production of IL-2 from activated T lymphocytes. The factor had no effect on TNF-induced cytotoxicity, but abrogated TNF-induced NF-kappa B activation. Surprisingly, a synergy was observed between the factor and phorbol ester-directed NF-kappa B activation. The factor had no effect on IL-1- or LPS-induced NF-kappa B activity, indicating selective activity of the factor. The factor did not inhibit the degradation of I kappa B alpha induced by TNF, indicating that the target for its activity lies within an undefined part of the TNF signaling mechanism. The data indicate that the localized immunosuppression associated with Buruli ulcer relates to the activity of the released factor, and this may provide a target for future therapeutic strategies for this intractable disease.