Pangenome comparison of Bacteroides fragilis genomospecies unveils genetic diversity and ecological insights

Bacteroides fragilis is a Gram-negative commensal bacterium commonly found in the human colon, which differentiates into two genomospecies termed divisions I and II. Through a comprehensive collection of 694 B. fragilis whole genome sequences, we identify novel features distinguishing these divisions. Our study reveals a distinct geographic distribution with division I strains predominantly found in North America and division II strains in Asia. Additionally, division II strains are more frequently associated with bloodstream infections, suggesting a distinct pathogenic potential. We report differences between the two divisions in gene abundance related to metabolism, virulence, stress response, and colonization strategies. Notably, division II strains harbor more antimicrobial resistance (AMR) genes than division I strains. These findings offer new insights into the functional roles of division I and II strains, indicating specialized niches within the intestine and potential pathogenic roles in extraintestinal sites.ImportanceUnderstanding the distinct functions of microbial species in the gut microbiome is crucial for deciphering their impact on human health. Classifying division II strains as Bacteroides fragilis can lead to erroneous associations, as researchers may mistakenly attribute characteristics observed in division II strains to the more extensively studied division I B. fragilis. Our findings underscore the necessity of recognizing these divisions as separate species with distinct functions. We unveil new findings of differential gene prevalence between division I and II strains in genes associated with intestinal colonization and survival strategies, potentially influencing their role as gut commensals and their pathogenicity in extraintestinal sites. Despite the significant niche overlap and colonization patterns between these groups, our study highlights the complex dynamics that govern strain distribution and behavior, emphasizing the need for a nuanced understanding of these microorganisms

Systematic Review and Meta-Analysis of Local Recurrence Rates of Head and Neck Cutaneous Melanomas after Wide Local Excision, Mohs Micrographic Surgery, or Staged Excision

Background Prospective trials have not compared local recurrence rates for different excision techniques for cutaneous melanomas on the head and neck. Objective To determine local recurrence rates of cutaneous head and neck melanoma after wide local excision (WLE), Mohs micrographic surgery (MMS), or staged excision. Methods A systematic review of PubMed, EMBASE, and Web of Science identified all English case series, cohort studies and randomized controlled trials that reported local recurrence rates after surgery of cutaneous head and neck melanoma. A meta-analysis utilizing a random effects model calculated weighted local recurrence rates and confidence intervals (CI) for each surgical technique and for subgroups of MMS and staged excision. Results Among one-hundred manuscripts with 13,998 head and neck cutaneous melanomas, 51.0% (7138) of melanomas were treated by WLE; 34.5% (4,826) by MMS; and 14.5% (2,034) by staged excision. Local recurrence rates were lowest for MMS (0.61%; 95%CI, 0.1%-1.4%); followed by staged excision (1.8%; 95%CI, 0.1%-2.9%) and WLE (7.8%; 95%CI, 6.4%-9.3%). Limitations Definitions of local recurrence varied. Surgical techniques included varying proportions of invasive melanomas. Studies had heterogeneity. Conclusion Systematic review and meta-analysis show lower local recurrence rates for cutaneous head and neck melanoma after treatment with MMS or staged excision compared to WLE

Systematic Review and Meta-Analysis of Local Recurrence Rates of Head and Neck Cutaneous Melanomas after Wide Local Excision, Mohs Micrographic Surgery, or Staged Excision

Background Prospective trials have not compared local recurrence rates for different excision techniques for cutaneous melanomas on the head and neck. Objective To determine local recurrence rates of cutaneous head and neck melanoma after wide local excision (WLE), Mohs micrographic surgery (MMS), or staged excision. Methods A systematic review of PubMed, EMBASE, and Web of Science identified all English case series, cohort studies and randomized controlled trials that reported local recurrence rates after surgery of cutaneous head and neck melanoma. A meta-analysis utilizing a random effects model calculated weighted local recurrence rates and confidence intervals (CI) for each surgical technique and for subgroups of MMS and staged excision. Results Among one-hundred manuscripts with 13,998 head and neck cutaneous melanomas, 51.0% (7138) of melanomas were treated by WLE; 34.5% (4,826) by MMS; and 14.5% (2,034) by staged excision. Local recurrence rates were lowest for MMS (0.61%; 95%CI, 0.1%-1.4%); followed by staged excision (1.8%; 95%CI, 0.1%-2.9%) and WLE (7.8%; 95%CI, 6.4%-9.3%). Limitations Definitions of local recurrence varied. Surgical techniques included varying proportions of invasive melanomas. Studies had heterogeneity. Conclusion Systematic review and meta-analysis show lower local recurrence rates for cutaneous head and neck melanoma after treatment with MMS or staged excision compared to WLE

Pathogenic WDFY3 variants cause neurodevelopmental disorders and opposing effects on brain size

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