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Objective:To analyze drug resistance, virulence and molecular epidemiological characteristics of Staphylococcus aureus ( S. aureus) isolated from skin sites of suppurative infections, and to provide an experimental basis for clinical anti-infective therapies. Methods:Swab samples from suppurative skin lesions and nasal secretions were collected from inpatients in Department of Dermatology, the Affiliated Hospital of Inner Mongolia Medical University from May 2020 to December 2020, and subjected to bacterial isolation and culture. Suspected S. aureus colonies were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Drug sensitivity test was conducted by using the broth microdilution method. Virulence genes of S. aureus were amplified by PCR, and real-time fluorescence-based quantitative PCR was performed to determine the relative expression of 4 virulence genes including tsst-1, pvl, hla and clfA in S. aureus strains from different sources. S. aureus strains were genotyped by multilocus sequence typing. Drug resistance rates and detection rates of virulence genes were compared by using chi-square test or Fisher′s exact test, and measurement data among groups were compared by using t test or Mann-Whitney U test. Results:A total of 85 strains of S. aureus were isolated from 210 inpatients, including 54 isolates from skin sites of suppurative infections (case group) and 31 isolates from the nasal cavity (control group) . Drug sensitivity test showed that 14 strains of methicillin-resistant S. aureus (MRSA) were identified among 85 strains of S. aureus. The resistance rate to penicillin was the highest (90.59%, 77/85) in the 85 S. aureus strains; the resistance rates to clindamycin and erythromycin were 60.00% (51/85) and 61.18% (52/85) respectively; no strains showed resistance to rifampicin, vancomycin or linezolid. PCR showed that the detection rate of the pvl gene was 33.33% (18/54) in the case group, which was significantly higher than that in the control group (12.90%, 4/31; χ2= 4.28, P= 0.038) . Real-time fluorescence-based quantitative PCR showed that the relative expression level of the clfA gene was significantly higher in the control group (3.87[2.30, 5.94]) than in the case group (1.63[0.95, 2.62], P= 0.007) . A total of 17 ST types were identified among the 85 strains of S. aureus, and the dominant types were ST398-methicillin-susceptible S. aureus (20/71) and ST22-MRSA (9/14) . The detection rate of the virulence gene pvl was significantly higher in the ST22-MRSA strain (14/14) than in the non-ST22 MRSA strains (0, P < 0.001) . Conclusions:S. aureus strains isolated from the skin sites of suppurative infections were highly resistant to penicillin, clindamycin and erythromycin, so these antibiotics should not be used as the first-choice empiric treatment. The occurrence of cutaneous S. aureus infections may be associated with the virulence gene pvl, and the nasal colonization of S. aureus may be associated with the clfA gene.
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Objective:To investigate the genetic correlation of interleukin-12 (IL-12) pathway-related gene single nucleotide polymorphisms (SNPs) with psoriasis vulgaris and their interaction with HLA-Cw*0602 in populations of Mongolian and Han nationalities in Inner Mongolia.Methods:From December 2012 to March 2018, 1 409 inpatients with psoriasis vulgaris (1 030 of Han nationality and 379 of Mongo-lian nationality) and 1 483 healthy controls (965 of Han nationality and 518 of Mongolian nationality) were collected from the Affiliated Hospital of Inner Mongolia Medical University, and served as patient group and control group respectively. Five milliliters of peripheral venous blood samples were collected from these subjects, and DNA was extracted. Nine SNPs located in the coding regions of IL-12 pathway-related genes were selected, including IL-12B (rs2082412, rs2288831, rs3212227, rs3213094, rs7709212) , IL-23R (rs11209026, rs2201841, rs7530511) and IL-28RA (rs4649203) genes, and detected by next-generation sequencing. HLA-Cw*0602 was genotyped by polymerase chain reaction with sequence-specific primers (PCR-SSP) . Statistical analysis was carried out with PLINK1.07 software, Chi-square test was used to compare allele frequencies between the 2 groups, relative risk estimates of alleles were calculated by using odds ratio ( OR) , and chi-square test for R × C contingency tables was used for haplotype analysis. Results:The allele frequencies of rs2082412, rs2288831, rs3212227, rs3213094 and rs7709212 in the IL-12B gene were significantly lower in the patients with psoriasis vulgaris of Han nationality than in the controls of Han nationality (all P < 0.005) ; the allele frequency of rs3213094 in the IL-12B gene was significantly lower in the patients of Mongolian nationality than in the controls of Mongolian nationality ( P < 0.005) . The prevalence of HLA-Cw*0602 was significantly lower in the patients with psoriasis vulgaris of Han and Mongolian nationalities than in the controls of corresponding nationalities (both P < 0.005) . As stratification analysis showed, the allele frequencies of rs2082412, rs2288831, rs3212227, rs3213094 and rs7709212 in the IL-12B gene were significantly lower in HLA-Cw*0602-positive patients of Han nationality than in HLA-Cw*0602-positive controls of Han nationality (all P < 0.005) , while there was no significant difference between HLA-Cw*0602-negative patients of Han nationality and HLA-Cw*0602-negative controls of Han nationality (all P > 0.05) . Among the HLA-Cw*0602-positive or negative populations of Mongolian nationality, no significant difference was observed in the allele frequencies between the patients and controls (all P > 0.005) . Haplotypes were constructed using 5 SNPs in the IL-12B gene, and there was no significant difference in the frequencies of 6 haplotypes between the patients and controls of Mongolian or Han nationality (all P > 0.005) ; stratification analysis showed that there was no significant difference in the frequencies of 7 haplotypes between HLA-Cw*0602-positive/negative patients and controls of Mongolian or Han nationality (all P > 0.005) . Conclusion:IL-12 pathway-related gene polymorphisms are associated with psoriasis vulgaris in the populations of Mongolian and Han nationalities in Inner Mongolia, and there may be interaction between IL-12B and HLA-Cw*0602 in the occurrence of psoriasis vulgaris.
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Objective:To investigate the relationship of polymorphisms in metabolic syndrome-related genes with psoriasis vulgaris (PsV) and their interaction with HLA-C*06:02 in populations of Mongolian nationality.Methods:Totally, 379 PsV inpatients of Mongolian nationality and 518 healthy controls of Mongolian nationality were collected from the Affiliated Hospital of Inner Mongolia Medical University from December 2012 to March 2018. Sixteen previously reported single nucleotide polymorphisms (SNPs) and HLA-C*06:02, which were related to metabolic syndrome and its components, were selected. Next-generation sequencing and polymerase chain reaction-sequence specific primer (PCR-SSP) typing were performed to determine the genotypes of these subjects. Minor allele frequencies of the 16 mutation sites and HLA-C*06:02 were calculated in the PsV group and control group, and chi-square test was used to analyze the differences in the minor allele frequencies of SNPs between the 2 groups.Results:There was no significant difference in the minor allele frequencies of the 16 SNPs susceptible to metabolic syndrome between the Mongolian PsV patients and healthy controls (all P > 0.05), while the minor allele frequency of HLA-C*06:02 significantly differed between the 2 groups ( P = 4.09 × 10 -35, OR = 3.41). Among the HLA-C*06:02-positive subjects, the minor allele frequencies of rs7593730_T and rs6931514_G significantly differed between the 252 PsV patients and 191 healthy controls ( P = 0.016, OR = 0.64; P = 0.041, OR = 1.33, respectively) ; no significant difference was observed in the minor allele frequencies of the 16 SNPs between the PsV patients and healthy controls among the HLA-C*06:02-negative subjects ( P > 0.05) . Conclusion:The SNPs of rs7593730 and rs6931514 may be related to PsV in populations of Mongolian nationality in Inner Mongolia, and may interact with HLA-C*06:02.
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Objective To investigate association between polymorphisms of the tumor necrosis factor α-induced protein 3 (TNFAIP3)interacting protein 1 (TNIP1)gene and systemic lupus erythematosus (SLE)in a Chinese Han population. Methods Blood samples were collected from 284 patients with SLE of Han nationality(SLE group)and 630 healthy controls of Han nationality (control group). Ligase detection reaction (LDR)was performed to determine the genotypes of 120 single nucleotide polymorphisms (SNPs)in the TNIP1 gene. Data were analyzed with the PLINK 1.07 package and Haploview software. Results After quality control, data on 105 SNPs underwent statistical analysis finally. Four SNPs including rs3805433, rs12516176, rs6869605 and rs4958882 in the TNIP1 gene were significantly associated with SLE (OR: 1.50 - 1.53, all P < 4.72 × 104), and there was a significant increase in the frequency of rs3805433 C, rs12516176 C, rs6869605 C and rs4958882 G alleles in the SLE group (0.301 - 0.306)compared with the control group (0.221 - 0.225). There was strong linkage disequilibrium between these 4 SNPs (r2 ≥ 0.871, D′ ≥ 0.938). In addition, moderate linkage disequilibrium was observed between these 4 SNPs and a previously reported SLE-related SNP rs10036748 (r2 ≥ 0.073, D′ ≥ 0.868). The frequency of the haplotype H2: CCCGT was significantly higher in the SLE group than in the control group(0.290 vs. 0.210, OR = 1.54, P < 4.72 × 10-4). Conclusion TNIP1 gene polymorphisms are associated with SLE in Chinese Han population.
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Objective To investigate the association between endoplasmic reticulum aminopeptidase 1 (ERAP1)gene polymorphisms and psoriasis vulgaris (PsV)in a Chinese Han population. Methods Five milliliters of venous blood samples were collected from 289 patients with PsV and 292 human controls of Han nationality after informed consent. Three single nucleotide polymorphisms (SNPs)in the encoding area of the ERAP1 gene, including rs27044, rs30187 and rs26653, were genotyped by ligase detection reaction (LDR). With the PLINK 1.07 package, statistical analysis was carried out by using the chi-square test for comparisons of allele and genotype frequencies between the patient group and control group. The allelic odds ratio (OR)and its 95% confidence interval (CI)were calculated. In addition, haplotype analysis was conducted with the Haploview software. Results The frequencies of rs30187-C and rs26653-G alleles were significantly lower in the patient group (0.460 2 and 0.430 8 respectively), especially in patients with early-onset PsV(0.448 5 and 0.422 7 respectively), than in the control group(0.534 2 and 0.501 7 respectively, all P <0.05). The SNPs rs27044, rs30187 and rs26653 showed strong linkage disequilibrium with each other (r2 ≥ 0.717, D′ ≥0.962). Genotype analysis showed that the frequency of the rs30187 CC genotype was significantly lower in the patient group, especially in patients with early-onset PsV, than in the control group (P < 0.05 and 0.016 7 respectively)under a recessive mode of inheritance. Haplotype analysis revealed that the frequency of the haplotype H4: CTC was significantly increased in the patient group(0.050), especially in patients with early-onset PsV(0.052), compared with the control group (0.022, P < 0.05 and 0.016 7 respectively). Conclusions ERAP1 gene polymorphisms are associated with PsV, especially with early-onset PsV in Chinese Han population. The risk haplotype H4: CTC may be a susceptible factor for PsV.
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Objective To investigate the association between polymorphisms in the tumor necrosis factor α-induced protein 3 (TNFAIP3)-interacting protein 1 (TNIP1) gene and psoriasis vulgaris in a Han population from north China.Methods Totally,465 patients with psoriasis vulgaris (PsV) and 476 healthy human controls were enrolled into the study.Five milliliters of venous blood samples were collected from these subjects after informed consent.Three single nucleotide polymorphisms (SNPs) in the TNIP1 gene,including rs17728338,rs3762999 and rs999556,were selected for genotyping with ligase detection reaction (LDR).With the PLINK 1.07 package,statistical analysis was carried out by using the chi-square test for comparisons of allele frequencies and genotype frequencies between the patient group and control group.The allelic odds ratio (OR) and its 95％ confidence interval (CI) were calculated.In addition,linkage disequilibrium analysis was performed for the three SNPs by calculating the r2 and D' values.Results There was a difference in the allele frequencies of the three SNPs between the patients with psoriasis vulgaris and controls,but the difference was statistically significant in only the allele frequencies of rs17728338,but not in those of the other two SNPs after Bonferroni correction.Under the dominant inheritance model,the genotype frequencies of the 3 SNPs all significantly differed between the patients and controls after Bonferroni correction (all P ＜ 0.016 7).Stratification analysis showed that there was a significant difference in the allele and genotype frequencies of the three SNPs between the patients with a family history and healthy controls (all P ＜ 0.016 7),and the frequency of A allele of rs17728338 was significantly lower in the controls than in the patients with psoriasis vulgaris,patients with early-onset psoriasis vulgaris (n =355),patients with late-onset psoriasis vulgaris (n =107),patients with a family history (n =68),and patients without a family history (n =394) (all P ＜ 0.0167).Strong linkage disequilibrium existed between rs3762999 and rs999556 (r2 =0.910,D' =0.982),and moderate linkage disequilibrium existed between rs17728338 and rs3762999 (r2 =0.371,D' =0.989) as well as rs999556 (r2 =0.353,D' =1).Conclusion The SNPs rs17728338,rs3762999 and rs999556 in the TNIP1 gene were associated with psoriasis vulgaris in the Chinese Han population.