| Purposes: By collecting clinical data of dermatology patients and performing molecular biology screening techniques and special staining on their paraffin-embedded tissue specimens.The general condition and clinical characteristics of patients with skin infectious granulomatous inflammation caused by different pathogenic bacteria in Dalian were reprepared to be learned.Then the characteristics of different experimental methods were summarized to provide experience for clinical diagnosis and treatment.Methods: By collecting case data of 80 patients diagnosed with skin infectious granulomatous inflammation by histopathological examination in dermatology department of the first affiliated hospital of Dalian medical university from January 2020 to July 2022.Statistical analysis of the patients’ general conditions,clinical manifestations,experimental findings and other relevant data were performed.Paraffin-embedded tissue specimens from each study subject were also tested for special staining,and DNA was extracted from theses samples and then tested for mycobacterium and mycobacterium marinum PCR qualitative assay,and all data were retrospectively analyzed and discussed.Results: 1.In the collection of 80 patients,45(56.25%)had clinical suspected cutaneous nontuberculous mycobacterial infections and 35(43.75%)had cutaneous fungal infections that confirmed by fungal culture.The fungal culture results showed 28 cases(80.00%)with Sporothrix and 7 cases(20.00%)with Candida.28(35.00%)of the 80 patients were male and 52(65.00%)were female,which with more females than males.The age distribution of all patients was 4-80 years,with a median age of 58.00(50.00,68.75)years.The largest number of people in the age group is between 40-80 years old(73 cases,91.25%)that being the main population with skin infectious granulomatous inflammation.2.The median duration of disease was 6.00(3.00,9.00)months in all patients.The median duration of disease in patients that clinical suspected cutaneous nontuberculous mycobacterial infection was 5.00(2.00,7.00)months.The median duration of disease in patients diagnosed with cutaneous fungal infections was 6.00(3.00,9.00)months,with a minimum duration of 1 month and a maximum duration of 24 months.3.The number of patients that clinical suspected cutaneous nontuberculous mycobacterial infection with a history of trauma was 31 cases(68.89%),with a predominance of seafood trauma(20 cases,44.44%).The number of patients that diagnosed with cutaneous fungal infections with a history of trauma was 24 cases(68.57%),most of them was unidentified trauma(14 cases,40%),followed by plant trauma(10 cases,28.57%).4.Among the 80 patients,the most common sites of onset was multiple upper extremities(34 cases,42.50%),followed by the dorsum of the hand(17 cases,21.25%),fingers(12cases,15.00%),forearm(10 cases,12.50%),face(5 cases,6.25%),and lower extremities(2 cases,2.50%).Among the patients with clinical suspected cutaneous nontuberculous mycobacterial infections,the mainly site of onset was upper extremities(25 cases,55.56%)and among those diagnosed with cutaneous fungal infections,the site of onset was predominantly the dorsum of the hand(11 cases,31.43%).5.In laboratory tests,T-spot examination was perfected in 34 patients with clinical suspected cutaneous nontuberculous mycobacterial infection,of which 25 were positive(73.53%).The number of patients diagnosed with cutaneous fungal infections who perfected T-spot examination was 7,of which 1 case(14.29%)was positive,and there was a statistically significant difference between the T-spot examination results of the two groups(P < 0.05).6.Paraffin-embedded tissue specimens from all patients were sectioned and then restain for acid-fast staining and PAS staining respectively.Among patients with clinical suspected cutaneous nontuberculous mycobacterial infection,PAS staining was negative and acid-fast staining was positive in 3 cases(3/45).Among patients diagnosed with cutaneous fungal infections,all acid-fast staining was negative and PAS staining was positive in 5 cases(5/35)7.DNA was extracted from all the tissue samples and detected qualitatively by mycobacterium fluorescence PCR melting curve assay and mycobacterium marinum dye method fluorescence quantitative PCR.Samples from patients with confirmed cutaneous fungal infection showed negative results in both PCR assays.In contrast,samples from patients with clinical suspected cutaneous nontuberculous mycobacterial infection were positive in 5 cases by the mycobacterium fluorescence PCR melting curve assay and in 2cases by the mycobacterium marinum dye method fluorescence quantitative PCR.Conclusion:1.The history of trauma in patients with skin infectious granulomatous inflammation caused by different pathogenic bacteria varies,with seafood trauma predominating in patients with clinical suspected cutaneous nontuberculous mycobacterial infection,yet unidentified trauma and plant trauma predominating in patients with confirmed cutaneous fungal infection.2.The T-spot examination is suggestive for the diagnosis of some nontuberculous mycobacteria,but it still needs to be combined with other methods such as pathogenic culture tests and molecular biology diagnostic techniques.3.The sensitivity of acid-fast staining and PAS staining in the diagnosis of skin infectious granulomatous inflammation is low,and confirmation of the diagnosis still relies on pathogenic culture and other tests.4.Fluorescence PCR melting curve assay and dye method fluorescent quantitative PCR assay can be used as a simple and rapid molecular biology diagnostic technique for the diagnosis of cutaneous nontuberculous mycobacterial infection,but the sensitivity and specificity need to be improved. |
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