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Background/AimsThe prevalence of colonic diverticulosis has been reported to be lower in Korea than in Western countries. This disease also shows markedly different characteristics in the Korean population. We describe herein a prospective investigation, based on colonoscopic examination, of the prevalence, clinical characteristics, and factors associated with colonic diverticulosis in Korea.MethodsThe prevalence of colonic diverticulosis has been reported to be lower in Korea than in Western countries. This disease also shows markedly different characteristics in the Korean population. We describe herein a prospective investigation, based on colonoscopic examination, of the prevalence, clinical characteristics, and factors associated with colonic diverticulosis in Korea.ResultsThe overall prevalence of colonic diverticulosis was 12.1% (103 / 848). The right side of the colon was involved in 84.5% of patients (87 / 103); patients with right side diverticula were, on average, younger than those with left side diverticulosis (p = 0.014). Multiple diverticula were observed in 60.2% (62 / 103) of patients. Age greater than 60 years, a high-fat diet, and alcohol consumption were significantly associated with the presence of colonic diverticulosis (p < 0.05).ConclusionsThe prevalence of colonic diverticulosis in Korea is increasing and is most commonly located in the right side of the colon. Further, old age and diet may affect the risk of development of this disease.

The most common cause of antibiotic-associated diarrhea is Clostridium difficile infection (CDI). Recurrent C. difficile infection (rCDI) often occurs after successful treatment of CDI. Due to the increased incidence and the difficulty in treating rCDI, it is becoming an important clinical issue. Identifying risk factors is helpful for early detection, treatment, and prevention of rCDI. Advanced age, use of antibiotics, gastric acid suppression, and infection with a hypervirulent strain are currently regarded as the major risk factors for rCDI. Several treatment modalities, including vancomycin, fidaxomicin, and fecal microbiota transplant (FMT), are suggested for rCDI treatment. However, there is currently no definitive treatment method with sufficient evidence for rCDI. Recent studies have focused on FMT and have shown positive results for rCDI. Prevention of rCDI by measures such as hand washing and isolation of patients is very important. However, these preventive measures are often overlooked in clinical practice. Here, we review the risk factors, treatment, and prevention of rCDI.

Rhodopsin-containing marine microbes such as those in the class Flavobacteriia play a pivotal role in the biogeochemical cycle of the euphotic zone (Fuhrman JA, Schwalbach MS, Stingl U. 2008. Proteorhodopsins: an array of physiological roles? Nat Rev Microbiol. 6:488–494). Deciphering the genome information of flavobacteria and accessing the diversity and ecological impact of microbial rhodopsins are important in understanding and preserving the global ecosystems. The genome sequence of the orange-pigmented marine flavobacterium Nonlabens dokdonensis (basonym: Donghaeana dokdonensis) DSW-6 was determined. As a marine photoheterotroph, DSW-6 has written in its genome physiological features that allow survival in the oligotrophic environments. The sequence analysis also uncovered a gene encoding an unexpected type of microbial rhodopsin containing a unique motif in addition to a proteorhodopsin gene and a number of photolyase or cryptochrome genes. Homologs of the novel rhodopsin gene were found in other flavobacteria, alphaproteobacteria, a species of Cytophagia, a deinococcus, and even a eukaryote diatom. They all contain the characteristic NQ motif and form a phylogenetically distinct group. Expression analysis of this rhodopsin gene in DSW-6 indicated that it is induced at high NaCl concentrations, as well as in the presence of light and the absence of nutrients. Genomic and metagenomic surveys demonstrate the diversity of the NQ rhodopsins in nature and the prevalent occurrence of the encoding genes among microbial communities inhabiting hypersaline niches, suggesting its involvement in sodium metabolism and the sodium-adapted lifestyle.

Streptomyces clavuligerus is an important industrial strain that produces a number of antibiotics, including clavulanic acid and cephamycin C. A high-quality draft genome sequence of the S. clavuligerus NRRL 3585 strain was produced by employing a hybrid approach that involved Sanger sequencing, Roche/454 pyrosequencing, optical mapping, and partial finishing. Its genome, comprising four linear replicons, one chromosome, and four plasmids, carries numerous sets of genes involved in the biosynthesis of secondary metabolites, including a variety of antibiotics.Streptomyces clavuligerus is a bacterium of industrial and clinical importance producing the ␤-lactamase inhibitor clavulanic acid (4), as well as cephamycin C (a ␤-lactam), clavams, tunicamycin, and holomycin (5,9,14,17). S. clavuligerus is intriguing in regard to its genetic structure and mechanism of cephamycin C, clavulanic acid, and clavam biosynthesis (19,20,21). Here, we present a draft genome sequence of the type strain NRRL 3585 (ATCC 27064). The specific clone used, SC2, is a single-spore isolate from the stock of NRRL 3585 that showed good sporulation and metabolite production, a typical example of the wild-type strain.The genome sequence was determined by Sanger paired-end sequencing (7) and Roche/454 pyrosequencing (12). Sanger reads at 4.9-fold coverage were produced from 4-or 40-kb genomic libraries, followed by 454 reads at 61.6-fold coverage. Sanger reads (14-fold coverage) provided by the Broad Institute were also utilized. The Sanger paired-end reads and the Newbler-assembled 454 contigs were assembled with a PCAP assembler (8). Optical mapping (Opgen, Inc.) was performed to confirm the assembly output and to assign contigs into each replicon. Gap closure was attempted using gap-spanning clones and PCR products. Coding sequences were predicted by the combined use of Glimmer (6), GeneMark (3), and CRITICA (2). Automatic functional annotation results obtained by AutoFACT (10) and the Rapid Annotation using Subsystem Technology (RAST) server (1) were compiled and validated with Artemis.The genome consists of one linear chromosome (58 contigs in 4 scaffolds, 6,736,475 bp, 72.69% GϩC) and four linear plasmids, pSCL1 (3 contigs in 2 scaffolds, 10,266 bp, 71.96% GϩC), pSCL2 (2 contigs in 2 scaffolds, 149,326 bp, 70.07% GϩC), pSCL3 (15 contigs in 2 scaffolds, 442,792 bp, 70.77% GϩC), and pSCL4 (11 contigs in 3 scaffolds, 1,796,117 bp, 71.85% GϩC). The 6.7-Mb chromosome is the smallest of the completely sequenced Streptomyces species. At least six rRNA operons and 66 tRNA genes as well as 7,898 protein-coding genes were annotated. Recently, a draft sequence of S. clavuligerus ATCC 27064 describing the 1.8-Mb megaplasmid was reported (13). The sequences of the chromosome and pSCL4 were nearly identical to our sequences. However, three other plasmids (15,22) are present only in our data, suggesting that our clone has preserved the genome in its intact form.A plethora of genes related to biosynthesis of secondary metabolites were discovered. The super...