The isolation and characterization of a novel, rapidly growing, scotochromogenic mycobacterial species is reported. Eight independent strains were isolated from clinical specimens from six different countries of the world, two in Iran, two in Italy and one in each of following countries: Greece, the Netherlands, Sweden and the USA. Interestingly, two of the strains were isolated from cerebrospinal fluid. The strains were characterized by rapid growth and presented orange-pigmented scotochromogenic colonies. DNA-based analysis revealed unique sequences in the four regions investigated: the 16S rRNA gene, the rRNA gene internal transcribed spacer 1 and the genes encoding the 65 kDa heat-shock protein and the beta-subunit of RNA polymerase. The phylogenetic analysis placed the strains among the rapidly growing mycobacteria, being most closely related to Mycobacterium gilvum . The genotypic and phenotypic data both strongly supported the inclusion of the strains investigated here as members of a novel species within the genus Mycobacterium; the name Mycobacterium iranicum sp. nov. is proposed to indicate the isolation in Iran of the first recognized strains. The type strain is M05T ( = DSM 45541T = CCUG 62053T = JCM 17461T).

The prevalence of drug resistance in this study area underscoring the need for further enforcement of TB control strategies in the Iran. Drug susceptibility testing for all TB cases to provide optimal treatment, establishing advanced diagnostic facilities for rapid detection of MDR-TB and continuous monitoring of drug resistance are recommended for prevention and control of drug-resistant TB.

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ObjectiveEnterococcus faecalis (E. faecalis) is the most frequently isolated strain in failed endodontic therapy cases since it is resistant to calcium hydroxide (CH). Whether a combination of CH and chlorhexidine (CHX) is more effective than CH alone against E. faecalis is a matter of controversy. Thus, the aim of this study was to conduct a systematic review and meta-analysis of the literature.Material and MethodsA comprehensive search in PubMed, EMbase, EBSCOhost, The Cochrane Library, SciELO, and BBO databases, Clinical trials registers, Open Grey, and conference proceedings from the earliest available date to February 1, 2013 was carried out and the relevant articles were identified by two independent reviewers. Backward and forward search was performed and then inclusion and exclusion criteria were applied. The included studies were divided into "comparisons" according to the depth of sampling and dressing period of each medicament. Meta-analysis was performed using Stata software 10.0. The level of significance was set at 0.05.ResultsEighty-five studies were retrieved from databases and backward/forward searches. Fortyfive studies were considered as relevant (5 in vivo, 18 in vitro, 18 ex vivo, and 4 review articles). Nine studies were included for meta-analysis. Inter-observer agreement (Cohen kappa) was 0.93. The included studies were divided into 21 comparisons for meta-analysis. Chi-square test showed the comparisons were heterogeneous (p<0.001). Random effect model demonstrated no significant difference between CH/CHX mixture and CH alone in their effect on E. faecalis (p=0.115).ConclusionsAccording to the evidence available now, mixing CH with CHX does not significantly increase the antimicrobial activity of CH against E. faecalis. It appears that mixing CH with CHX does not improve its ex vivo antibacterial property as an intracanal medicament against E. faecalis. Further in vivo studies are necessary to confirm and correlate the findings of this study with the clinical outcomes.

A strain isolated from a biopsy sample taken from a slowly spreading skin granulation on a child's hand was found to have properties consistent with its classification in the genus Mycobacterium. An almost complete gene sequence of the 16s rRNA of the strain was determined following the cloning and sequencing of the amplified gene. The sequence was aligned with those available for mycobacteria, and phylogenetic trees were inferred with four tree-making algorithms. The organism, which formed a distinct phyletic line within the evolutionary radiation occupied by rapidly growing mycobacteria, was readily distinguished from members of validly described species of rapidly growing mycobacteria on the basis of its mycolic acid pattern and a number of other phenotypic features, notably its ability to form yellow pigmented colonies when incubated in the light. The name proposed for this new species is Mycobacterium novocastrense. The type strain is DSM 44203.A relatively rapidly growing, weakly acid-alcohol-fast organism was isolated from biopsy tissue of a patient who had received six weeks of antituberculosis therapy. The strain had phenotypic properties consistent with its classification in the genus Mycobacterium, and these set it apart from other rapidly growing mycobacteria. In the present investigation, the organism was the subject of a polyphasic taxonomic study designed to clarify its taxonomic position. The results indicate that the organism represents a new species, for which the name Mycobacterium novocastrense is proposed. MATERIALS AND METHODSOrganism and culture conditions. The organism (strain 73), which was isolated on Lowenstein-Jensen medium (9) after 9 weeks of growth at 36T, was obtained from a biopsy sample taken from a slowly spreading skin granulation on the hand of a six-year-old child. It was then cultivated on Columbia blood agar (4), Lowenstein-Jensen medium (9), MacConkey agar (IS), Middlebrook 7H10 agar (17), and 5% (wt/vol) sodium chloride agar (13) for between 3 and 10 days at 25°C and 36°C. The strain, which was maintained on Middlebrook 7H10 agar (17), was grown at 36°C in all of the remaining tests.Phenotypic characterization. The growth, temperature, and sensitivity studies were carried out on Middlebrook 7H10 agar (17). The Gram (16) and ZiehlNeelsen (20) stains were performed on cells grown for 5 days at 36°C on this medium. Catalase (14) and niacin (12) activity were examined after 10 days, and the production of arylsulfatase (29) was examined after 3 and 14 days. Similarly, iron uptake (27) and Tween hydrolysis (28) were detected after 10 days at 36°C.Extraction and analysis of mycolic acids. Lyophilized biomass from 10-day-old Middlebrook 7H10 agar plates was degraded by alkaline methanolysis (23) and two-dimensional thin-layer chromatography of the methanolysates carried out as described previously (19).Sequencing of genes coding for 16s rRNA (16s rDNA). The biomass of the test strain needed for sequencing was obtained from a 5-day-old Liiwenstein-Jensen (9) slant incubated at 36...

A strain isolated from a lung abscess in an elephant that died from chronic respiratory disease was found to have properties consistent with its classification in the genus Mycobacterium. An almost complete sequence of the 16S rDNA of the strain was determined following the cloning and sequencing of the amplified gene. The sequence was aligned with those available on mycobacteria and phylogenetic trees inferred by using three treemaking algorithms. The organism, which formed a distinct phyletic line within the evolutionary radiation occupied by rapidly growing mycobacteria, was readily distinguished from members of validly described species of rapidly growing mycobacteria on the basis of its mycolic acid pattern and by a number of other phenotypic features, notably its ability to grow at higher temperatures. The type strain is Mycobacterium elephantis DSM 44368 T .

Background:Tuberculosis is one of the most important infectious diseases that has claimed its victims throughout much of known human history. With Koch's discovery of the tubercle bacillus as the etiologic agent of the disease, his sanitary and hygienic measures, which were based on his discovery and the development of a vaccine against tuberculosis by Albert Calmette and Camille Guérin in 1921, an attenuated Mycobacterium bovis strain, bacilli Calmette-Guérin (BCG), and the discovery of the first antibiotic against tuberculosis, streptomycin by Selman Waksman in 1943, soon led to the opinion that appropriate control measures had become available for tuberculosis and it had been assumed that the disease could ultimately be eradicated.The emergence of resistant strains of this bacteria and widespread distribution of the disease in the world, and the emergence of the AIDS epidemic destroyed any possibility of global control of tuberculosis in the foreseeable future.Objectives:The purpose of this review is to highlight the current scientific literature on mycobacterial infections and provide an overview on the laboratory diagnosis of tuberculosis and non-tuberculosis infections based on conventional phenotypic and modern molecular assays.Method:In this study, a number of 65 papers comprising 20 reviews, 9 case reports, and 36 original research in association with mycobacteriosis and the laboratory diagnosis of mycobacterial infections, were reviewed.Results:Based on our analysis on the published documents methods applied for the laboratory diagnosis of tuberculosis are continually assessed and developed in order to achieve more rapid, less expensive, and accurate results. Acid-fast staining and culture for mycobacteria remain at the core of any diagnostic algorithm with the sensitivity of 20-70% and specificity of 95-98% for AFB microscopy and the sensitivity of 95% and the specificity of 98% for culture based diagnosis. Following growth in culture, molecular tests such as nucleic acid hybridization probes and DNA sequencing may be used for definitive species identification. Nucleic acid amplification methods provide the means for direct detection of Mycobacterium tuberculosis in respiratory specimens without the prerequisite to isolate or culture the organism, leading to more rapid diagnosis and better patient care.Conclusion:As the researchers in a developing country, we strongly believe that despite significant advances in laboratory capacity, in many countries reliable confirmation of suspected mycobacterial diseases is hindered by a lack of knowledge on proper standardized methods, sufficient funds, suitably trained staff and laboratory supplies.

BackgroundClostridium difficile infection (CDI) is known as one of the most important causes of nosocomial infections. The main objective of this study was to evaluate the presence of Clostridium difficile in the stool of hospitalized patients with diarrhea as well as in their environments.MethodsC. difficile isolates were characterized according to the presence of toxin genes and antibiotic resistance. Multilocus Sequence Typing Analysis (MLST) was applied for finding the genetic polymorphism and relationship among strain lineages.ResultsA total of 821 samples (574 stools and 247 swabs) were collected between April 2015 and May 2017. The prevalence of C. difficile isolates was 28.6% (164/574) in patients and 19% (47/247) in swabs taken from medical devices, hands of healthcare workers and skin patient sites. Finally, 11.5% (66/574) toxigenic C. difficile strains isolated from stool samples of inpatients and 4.4% (11/247) from hands of healthcare workers and skin patient sites. All the toxigenic isolates were inhibited by a low concentration of vancomycin (MIC < 0.5 μg/ml). About 43% (33/77) and 39% of isolates were resistant to Clindamycin and moxifloxacin respectively. All isolates were susceptible to metronidazole. Toxigenic C. difficile strains were analyzed by MLST and were divided into 4 different STs. The detected types were ST-54 (57.9%), followed by ST-2 (31.6. %), ST-15 (5.3%) and ST-37 (5.3%), while none of the isolates were identified as ST-1 or ST-11. Significant risk factors for CDI appear to be advanced age, undergoing chemotherapy, previous surgery, and residence in the nursing home.ConclusionsCDI is common in Iran and further studies are recommended to monitor its epidemiological variations. Moreover, greater attempts must be made to encourage antibiotic stewardship by healthcare workers and the public.