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Objectives Genetic determinants conferring resistance to macrolide, lincosamide, and streptogramin B (MLS B ) via ribosomal modification such as, erm , msrA/B and ereA/B genes are distributed in bacteria. The main goals of this work were to evaluate the dissemination of MLS B resistance phenotypes and genotypes in methicillin-resistant Staphylococcus aureus (MRSA) isolates collected from clinical samples. Methods A total of 106 MRSA isolates were studied. Isolates were recovered from 3 hospitals in Tehran between May 2016 to July 2017. The prevalence of MLS B -resistant strains were determined by D-test, and then M-PCR was performed to identify genes encoding resistance to macrolides, lincosamides, and streptogramins in the tested isolates. Results The frequency of constitutive resistance MLS B , inducible resistance MLS B and MS B resistance were 56.2%, 22.9%, and 16.6%, respectively. Of 11 isolates with the inducible resistance MLS B phenotype, ermC , ermB , ermA and ereA were positive in 81.8%, 63.6%, 54.5% and 18.2% of these isolates, respectively. In isolates with the constitutive resistance MLS B phenotype, the prevalence of ermA , ermB , ermC , msrA , msrB , ereA and ereB were 25.9%, 18.5%, 44.4%, 0.0%, 0.0%, 11.1% and 0.0%, respectively. Conclusion Clindamycin is commonly administered in severe MRSA infections depending upon the antimicrobial susceptibility findings. This study showed that the D-test should be used as an obligatory method in routine disk diffusion assay to detect inducible clindamycin resistance in MRSA so that effective antibiotic treatment can be provided.

Nano-silver and nano-titanium oxide films can be coated over brackets in order to reduce bacterial aggregation and friction. However, their antimicrobial efficacy, surface roughness, and frictional resistance are not assessed before. Fifty-five stainless-steel brackets were divided into 5 groups of 11 brackets each: uncoated brackets, brackets coated with 60 µm silver, 100 µm silver, 60 µm titanium, and 100 µm titanium. Coating was performed using physical vapor deposition method. For friction test, three brackets from each group were randomly selected and tested. For scanning electron microscopy and atomic-force microscopy assessments, one and one brackets were selected from each group. For antibacterial assessment, six brackets were selected from each group. Of them, three were immediately subjected to direct contact with S. mutans. Colonies were counted 3, 6, 24, and 48 h of contact. The other three were stored in water for 3 months. Then were subjected to a similar direct contact test. Results pertaining to both subgroups were combined. Groups were compared statistically. Mean (SD) friction values of the groups 'control, silver-60, silver-100, titanium-60, and titanium-100' were 0.55 ± 0.14, 0.77 ± 0.08, 0.82 ± 0.11, 1.52 ± 0.24, and 1.57 ± 0.41 N, respectively (p = .0004, Kruskal-Wallis). Titanium frictions were significantly greater than control (p < .05), but silver groups were not (p > .05, Dunn). In the uncoated group, colony count increased exponentially within 48 h. The coated groups showed significant reductions in colony count (p < .05, two-way-repeated-measures ANOVA). In conclusions, all four explained coatings reduce surface roughness and bacterial growth. Nano-titanium films are not suitable for friction reduction. Nano-silver results were not conclusive and need future larger studies.

Background:Otomycosis is an external ear canal infection caused by various fungi. This disease is prevalent in some tropical and subtropical regions or countries.Objectives:Given the crucial role of fungal agents in the treatment of the disease, the aim of the present study was to identify the fungi in ear canal of patients with otomycosis admitted to the hospitals in Babol City, Iran.Patients and Methods:This study included 56 patients with otomycosis. After removal of ear infectious samples, some of them were placed on the slides for direct examination and also a portion of them was plated on the Sabouraud dextrose agar with chloramphenicol for fungal growth. The slides were studied for the presence of fungal elements. Conventional methods were performed to determine fungal colonies.Results:Thirty-three patients (55.36%) were female and the rest were male. Fungal elements were observed in 11 cases (19.64%) in the direct examination, alone, and 45 specimens (80.36%) had fungi and bacteria combined. Septate mycelia, with 43 cases, had the most frequent fungal elements in direct examination. Aspergillus and Candida genera were the prevalent fungal colonies in culture media.Conclusions:According to the role of different genera of fungi in the process of otomycosis, much attention on the macroscopic and microscopic examination of the samples leads to special treatment decisions of a physician.

BackgroundAcute otitis externa, an inflammatory condition of the external auditory canal, is a common clinical problem in general medicine.ObjectivesThis study aimed to determine the etiology of otitis externa in patients from the Mazandaran province, north of Iran, which has a humid climate, as humidity can affect the prevalence of pathogenic microorganisms.Patients and MethodsThis cross-sectional study involved 116 patients with otitis externa. Two sets of samples were collected from their ears; one set was used for slide preparations, and the other for microbial culturing. After culturing, the microorganisms were identified by conventional methods.ResultsPatients between 35 and 44 years of age were most frequently affected (25.00%) by otitis externa (average age, 43.87 ± 18.08 years). Moreover, women (54.31%) were more frequently affected than men (45.69%). Upon direct investigation, Gram-positive bacilli were the most commonly identified microorganisms (22.41%). Furthermore, Bacillus spp. and coagulase-negative staphylococci (22.41% and 19.83%, respectively), were the organisms most frequently identified from cultures of otitis externa samples.ConclusionsDirect examination and culture showed that a mixed infection of fungi and bacteria is the most common cause of otitis externa. The present study revealed that Bacilli spp. were the most abundant bacteria isolated from patients with otitis externa. Thus, it is recommended that both organisms should be considered as etiologic agents in protocols for treatment of otitis externa.