IMPORTANCE Integrated information on the global prevalence and incidence of oral lichen planus (OLP) is lacking.OBJECTIVE To examine the global prevalence and incidence of OLP in a systematic review and meta-analysis.DATA SOURCES A systematic review of population-based studies and clinic-based studies reporting the prevalence and incidence of OLP was performed using 3 electronic medical databases (Cochrane Database of Systematic Reviews, Embase, and MEDLINE) from their inception to March 2019. The search terms included "(lichen planus or LP) and (prevalence or incidence or epidemiology)." No language restriction was applied.STUDY SELECTION Observational descriptive studies investigating the prevalence and incidence of OLP were included.DATA EXTRACTION AND SYNTHESIS Data were extracted by continent, sex, and other characteristics. The risk of bias was assessed by the Joanna Briggs Institute Critical Appraisal Instrument for Studies Reporting Prevalence Data using random-effects models to synthesize available evidence. MAIN OUTCOMES AND MEASURESThe primary outcome was the prevalence (with 95% CIs) of OLP among the overall population and among subgroups. Between-study heterogeneity was assessed using the I 2 statistic. RESULTS Among 46 studies, the overall pooled estimated prevalence of OLP was 0.89% (95% CI, 0.38%-2.05%) among the general population (n = 462 993) and 0.98% (95% CI, 0.67%-1.43%) among clinical patients (n = 191 963). Among the 15 population-based studies, the prevalence of OLP was 0.57% (95% CI, 0.15%-2.18%) in Asia, 1.68% (95% CI, 1.09%-2.58%) in Europe, and 1.39% (95% CI, 0.58%-3.28%) in South America. Among the 31 clinic-based studies, the prevalence was 1.43% (95% CI, 1.12%-1.83%) in Africa, 0.87% (95% CI, 0.61%-1.25%) in Asia, 1.03% (95% CI, 0.51%-2.09%) in Europe, 0.11% (95% CI, 0.07%-0.16%) in North America, and 3.18% (95% CI, 0.97%-9.95%) in South America. The pooled prevalence of OLP by sex was 1.55% (95% CI, 0.83%-2.89%) for women and 1.11% (95% CI, 0.57%-2.14%) for men in the population-based studies and 1.69% (95% CI, 1.05%-2.70%) for women and 1.09% (95% CI, 0.67%-1.77%) for men in the clinic-based studies. In 5 clinic-based studies providing the age distribution of patients with OLP, the prevalence by age was 0.62% (95% CI, 0.33%-1.13%) among patients younger than 40 years and 1.90% (95% CI, 1.16%-3.10%) among patients 40 years and older.CONCLUSIONS AND RELEVANCE This study identified the global prevalence and incidence of OLP in terms of its spatial, temporal, and population distribution. The overall estimated pooled prevalence of OLP was 0.89% among the general population and 0.98% among clinical patients. A higher prevalence of OLP was found in non-Asian countries, among women, and among people 40 years and older. The findings should be considered with caution because of the high heterogeneity of the included studies.

BackgroundThe aim of this study was to assess the disk diffusion technique against E‐test as a routine antibiotic susceptibility testing method for Helicobacter pylori.Materials and methodsSusceptibilities of 301 H pylori clinical isolates were simultaneously profiled by E‐test and disk diffusion method for levofloxacin (5‐μg disk), clarithromycin (15‐μg disk), metronidazole (5‐μg disk), amoxicillin (10‐μg disk), and tetracycline (30‐μg disk). Furazolidone susceptibility was evaluated using a 100‐μg disk only. The correlation between MICs by E‐test and inhibition zone diameters by disk diffusion was assessed by linear regression analysis.ResultsCorrelation between inhibition zone diameters and MICs was found for levofloxacin (r = −.932), clarithromycin (r = −.894), and to a minor extent metronidazole (r = −.820). Using the linear regression analysis, the inhibition zone diameter breakpoints were calculated to be 29 mm for levofloxacin, 41 mm for clarithromycin, and 15 mm for metronidazole corresponding to the EUCAST‐recommended MIC breakpoints. The susceptibility agreement between E‐test and disk diffusion for levofloxacin, clarithromycin, and metronidazole was 98.6%, 96.0%, and 96.7%, respectively. The inhibition zone diameters recorded for the amoxicillin, tetracycline, and furazolidone were large (approximately 60 mm in mean), and a poor correlation was found between inhibition zone diameters and MICs for amoxicillin (r = −.594) and tetracycline (r = −.490).ConclusionsThe disk diffusion can be used as a routine H pylori susceptibility testing method for levofloxacin, clarithromycin, and metronidazole in clinical practice under the described technical conditions. The use of disk diffusion for amoxicillin, tetracycline, and furazolidone susceptibility testing needs to be further studied.

The lipopolysaccharide O-antigen structure expressed by the European Helicobacter pylori model strain G27 encompasses a trisaccharide, an intervening glucan-heptan and distal Lewis antigens that promote immune escape. However, several gaps still remain in the corresponding biosynthetic pathway. Here, systematic mutagenesis of glycosyltransferase genes in G27 combined with lipopolysaccharide structural analysis, uncovered HP0102 as the trisaccharide fucosyltransferase, HP1283 as the heptan transferase, and HP1578 as the GlcNAc transferase that initiates the synthesis of Lewis antigens onto the heptan motif. Comparative genomic analysis of G27 lipopolysaccharide biosynthetic genes in strains of different ethnic origin revealed that East-Asian strains lack the HP1283/HP1578 genes but contain an additional copy of HP1105 and JHP0562. Further correlation of different lipopolysaccharide structures with corresponding gene contents led us to propose that the second copy of HP1105 and the JHP0562 may function as the GlcNAc and Gal transferase, respectively, to initiate synthesis of the Lewis antigen onto the Glc-Trio-Core in East-Asian strains lacking the HP1283/HP1578 genes. In view of the high gastric cancer rate in East Asia, the absence of the HP1283/HP1578 genes in East-Asian H. pylori strains warrants future studies addressing the role of the lipopolysaccharide heptan in pathogenesis.

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Acne vulgaris is a kind of chronic inflammatory dermal disorder that occurs in the sebaceous glands and hair follicles on face, neck, back, and chest, which has affected almost every adult and adolescent during their lifetime at a certain time. 1,2 Studies have shown that the incidence of acne is as high as 85%, which has greatly affected the psychology and quality of life of patients even though it is not life-threatening. 3 The clinical features of acne include seborrhea, noninflammatory lesion (including closed or open comedone), inflammatory lesion (pustule and papule), and scarring to different extents. Acne has complex pathogenesis. Currently, the occurrence and development of acne are found to be related to factors such as massive secretion of sebum under the action of androgen, the change in sebum composition, the abnormal keratosis of hair follicles and sebaceous glands, the