| Objective: Women in pregnancy experience changes in immunity,metabolism,endocrine,and blood vessels,to name a few.Skin and its appendages are prone to physiological and even pathological changes as well.The skin is a complex and changeable ecosystem with many microorganisms,including bacteria,fungi,and viruses on the surface.Skin microorganisms are closely related to several skin diseases.In recent years,due to the development and application of high-throughput sequencing,there have been more and more reports on the characteristics and changes of intestinal,vagina,saliva,teeth/gums and other microbial communities in women during pregnancy and postpartum.However,whether there will be changes in the skin microbiome during pregnancy and postpartum,remains to be investigated.Accordingly,this study aims to explore the correlation between skin flora and skin changes during pregnancy,the characteristics of skin flora in different sites of pregnant women,changes in skin flora during pregnancy and postpartum,and pregnant women and non-pregnant women.The differences in female skin flora provide new ideas for the related pathogenesis,diagnosis and treatment of skin changes during pregnancy.Methods: 1.Follow-up of facial skin changes in women during pregnancy(T1,T2,T3,T4,T5)and postpartum(T6).Using Seborrheic Dermatitis Severity Index(SDSI),modified Melasma Area and Severity Score(m MASI),erythema index,and melanin index to evaluate facial skin changes.Collect skin swab specimens and perform bacterial 16 S r RNA sequencing and fungal ITS1 sequencing.2.Explore the correlation between skin flora and facial seborrheic dermatitis during pregnancy.According to whether facial seborrheic dermatitis occurred during pregnancy follow-up,the swab samples(nasolabial fold)were divided into two groups,namely the seborrheic dermatitis group and the nonseborrheic dermatitis group.The differences in flora structure between the groups were compared.And used LEf Se to screen out the different species between the groups,and used Spearman correlation to analyze the correlation between the relative abundance of the differential taxa and the erythema index,and explore the correlation between skin flora and facial seborrheic dermatitis in pregnant women.3.Explore the correlation between skin flora and facial melasma during pregnancy.Patients with melasema during pregnancy selected cheekbone samples for bacterial and fungal diversity sequencing,and Spearman correlation was used to analyze the correlation between bacterial genera with relative abundance greater than 0.001 and melasma m MASI score.4.Compare the taxa and abundance of bacteria and fungi in different skin sites.Divide the swab samples into groups according to the sampling site,perform diversity sequencing,compare the cheekbone,nasolabial fold,and forearm skin flora taxonomic structure,Alpha diversity,Beta diversity,and screen different taxa between groups.Using exogenous reference molecules to compare the taxa and abundance of bacteria and fungi on different skin sites.5.Explore the influence of pregnancy on skin flora.Compare the taxonomic structure,Alpha diversity,and Beta diversity of the skin bacterial flora at the same site during pregnancy and postpartum longitudinally,and screen different taxa between the groups.Compare the pregnant group and the non-pregnant group horizontally,including the taxonomic structure,Alpha diversity,Beta diversity of the skin bacterial flora and differential taxa in the same sampling period and the same body sites.Results: 1.Facial seborrheic dermatitis and melasema are common skin changes involving female faces during pregnancy.105 subjects were followed up,23(21.90%)patients with facial seborrheic dermatitis,of which 82.61%(19/23)patients had clinical manifestations at T1(8.57±2.23 weeks).The clinical features of facial seborrheic dermatitis in pregnant women were mainly erythema in the middle of the face,which may be accompanied by chaff-like scaly,generally without symptoms.T6(5-7 weeks postpartum)erythema index on the nasolabial fold is lower than T1(11-13+6 weeks of gestation),T2(11-13+6 weeks of gestation),and T5(>38 weeks of gestation),The difference was statistically significant(P<0.05).There was a difference between the seborrheic dermatitis group and the control group in the Beta diversity of the bacteria on both nasolabial fold and cheekbone(P<0.05).LEf Se analysis found that the relative abundance of Propionibacterium and Staphylococcus in the seborrheic dermatitis group was high,and the relative abundance of Propionibacterium was positively correlated with the erythema index: r=0.45(P<0.05).The LEf Se analysis of fungi found that the relative abundance of Cryptococcus in the seborrheic dermatitis group was increased.The prevalence of facial melasema in pregnant women was 90.48%.The m MASI score of melasema was the highest at T5(P<0.05),and decreased after delivery.There was a correlation between the m MASI of melasema and the relative abundance of some taxa.2.The bacterial flora of pregnant women’s skin was mainly composed of Actinobacteria,Proteobacteria,Firmicutes,Cyanobacteria,Bacteroides,etc.at the "phylum" level,and mainly composed of Propionibacterium Corynebacterium,Pseudomonas,Lactobacillus,Deinococcus,etc.at the "genus" level.Observed＿species in the three selected sites of the pregnant woman’s skin from high to low were: forearm,cheekbone and nasolabial fold(P<0.05).The Beta diversity of the bacterial community in the forearm of pregnant women was significantly different from that of the face(P<0.05),but there was no significant difference in the Beta diversity of the cheekbone and nasolabial fold(P>0.05).LEf Se analysis found that the relative abundance of Lactobacillus on cheekbone in pregnant women was the highest,and the relative abundance of Propionibacterium on nasolabial fold was the highest.The relative abundance of Corynebacterium,Paracoccus,and Streptococcus was highest on forearm.Sequencing of skin fungi in pregnant women found that Malassezia is the main fungus on pregnant women’s skin,with Malassezia＿restricted having the greatest abundance,followed by Malassezia＿globosa.The Shannon index of the forearm fungal community and the Observed＿species were higher than those of the face(P<0.05).There was no significant difference in the Beta diversity of fungi between the three sites(P>0.05).LEf Se analysis found that the relative abundance of Cryptococcus was the highest on cheekbone,the relative abundance of Malassezia on nasolabial fold was the highest,and the relative abundance of Cladosporium and Schizophyllum was the highest on forearm.In order to compare the relative abundance of bacteria and fungi,the introduction of exogenous reference molecules detected that the relative abundance of bacteria was 95.63% and the relative abundance of fungi was 4.37% at the "genus" level,but there were large differences between individuals.There was no significant difference in the relative abundance of total bacteria on the cheekbone,nasolabial fold and forearm(P>0.05).3.There was no significant difference in Alpha diversity and Beta diversity during pregnancy and postpartum(P>0.05).LEf Se analysis found that the relative abundance of Brevibacterium on the forearm was the highest at T3(24-28 weeks of gestation).There was a significant difference between the bacterial Beta diversity of the cheekbone skin of pregnant women at T5 and the non-pregnant group(P<0.05),and the bacterial Beta diversity of the forearm skin of pregnant women at T3 was significantly different from that of the non-pregnant group(P<0.05).LEf Se analysis screened a total of 11 different bacterial genera between groups,among which Brevibacterium had the largest diversities between groups.Conclusion: 1.Facial seborrheic dermatitis in pregnant women usually has clinical manifestations before 14 weeks of gestation.The clinical features are mainly erythema in the middle of the face,which may be accompanied by chaff-like scales,generally without symptoms,and can be relieved in the postpartum period.There are differences in the bacterial flora structure of the skin between patients with facial seborrheic dermatitis and the control group during pregnancy.Propionibacterium,Staphylococcus,and Cryptococcus may be related to facial seborrheic dermatitis during pregnancy.Patients with melasema during pregnancy usually get onset before 14 weeks of gestation,which gradually aggravates during pregnancy and relieves after delivery.The severity of melasma is related to part of the skin flora.2.The structure of the bacterial flora in the dry skin area(forearm)of pregnant women is different from that of the cheekbone and nasolabial fold.The structure of the bacterial flora on the cheekbone of pregnant women is similar to that of the nasolabial fold.The bacterial species richness of the skin in descending order is the forearm,the cheekbone,and the nasolabial fold.Compared with the three skin sites,the relative abundance of Lactobacillus is higher on the cheekbone than that of the nasolabial fold and forearm,and the relative abundance of Propionibacterium on the nasolabial fold is higher than that of the cheekbone and forearm.The relative abundance of Corynebacterium,Paranococcus and Streptococcus is higher on forearm than that of the cheekbone and nasolabial fold.Malassezia is the main fungus on the cheekbone,the nasolabial fold,and the forearm of pregnant women.The Malassezia＿restricted has the highest abundance,followed by Malassezia＿globosa.The fungi species richness and species evenness of the forearm is higher than those of the cheekbone and nasolabial fold,but there is no significant difference in the composition of the three skin fungal communities.Among the three skin sites,the relative abundance of Cryptococcus is higher on cheekbone than that of the nasolabial fold and the forearm,and the relative abundance of Malassezia on the nasolabial fold is higher than that of the cheekbone and the forearm.The relative abundance of Schizophyllum and Schizophyllum is higher on the forearm than that of the cheekbone and nasolabial fold.At the “genus” level,the relative abundance of bacteria is 95.63%,and the relative abundance of fungi is 4.37%,but there are large differences between individuals.There is no significant difference in the relative abundance of total bacteria on the cheekbone,nasolabial fold and forearm.3.The structure of skin bacterial flora during pregnancy and postpartum has a high degree of stability.The bacterial community structure of the cheekbone skin of pregnant women over 38 weeks of gestation is significantly different from that of the non-pregnant control group.The bacterial community structure of the forearm skin of pregnant women between 24-28 weeks of gestation is significantly different from that of the non-pregnant control group.The relative abundance of Brevibacterium on the forearm of pregnant women is the highest at 24-28 weeks of gestation,and is higher than that of the non-pregnant control group,albeit its function remains to be tackled. |
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