[Mini-incision with endoscope-assisted surgery for bilateral congenital second branchial cleft fistula and a pedigree report]

Objective: To investigate the feasibility and efficacy of mini-incision with endoscope-assisted resection for bilateral congenital second branchial cleft fistula, and to report on a rare pedigree. Methods: The clinical data of 5 patients with bilateral congenital second branchial fistula admitted in Fujian Provincial Hospital from April 2007 to December 2018 were retrospectively reviewed, including 2 males and 3 females, aged from 3 to 31 years old. The surgical strateges and clinical experience of single mini-incision with endoscope-assisted fistulectomy were summarized, and a rare pedigree was reported. Results: In five patients, Case 1 to Case 4 were treated with bilateral endoscopic-assisted fistula high ligation with titanium clips and removal through a single small incision under general anesthesia. No obvious complications occurred after the operation. The patients were followed up for 40-164 months with no fistula recurrence. Case 5 gave up surgical resection and was followed up for 24 months with acute infection attack once. Case 2 and Case 4 came from the same family. In this family, 7 out of 31 members of four generations had second branchial cleft fistulas, of which 4 were bilateral and 3 were right. Pedigree analysis was consistent with autosomal dominant inheritance. No deafness, preauricular tag, external and middle ear deformity and kidney malformation were found in the family members. Conclusions: Bilateral congenital second branchial cleft fistula is rare. Surgical resection is the preferred treatment. Mini-incision with endoscopic-assisted fistula high ligation with titanium clip and resection has clear operative field, ideal cosmetic effect and definite curative effect.

Successful use of tofacitinib in epidermolysis bullosa pruriginosa

This case report describes 26-year-old woman who had multiple clusters of pale-pink lichenoid papules since childhood and the accompanying itching was intense. Skin biopsy revealed obvious fissures had formed under the epidermis. The patient was diagnosed with epidermolysis bullosa pruriginosa and was successfully treated with tofacitinib.

[Efficacy of the XEN gel stent on intraocular pressure lowering in glaucoma patients]

Objective: To evaluate the efficacy and safety of the XEN gel implant in the treatment of glaucoma. Methods: It was a retrospective case series study. Eight patients (8 eyes) in the First Affiliated Hospital of Fujian Medical University from January 2020 to September 2020 were included, including six males and two females, aged 29 to 74 years. The patients treated with the XEN gel implanting for glaucoma. After detailed ophthalmic examination, all the patients met the surgical indications for the XEN gel implanting. Preoperative and postoperative intraocular pressure (IOP), anterior segment and fundus examination results, medication, and surgical complications were evaluated. Results: There were seven patients with primary open-angle glaucoma and one patient with glaucomatocyclitic syndrome. Five patients had received anti-glaucoma surgeries, and the remaining three patients had not received surgical treatment. All XEN gel stents were implanted successfully. All patients were followed up for 4 to 12 months. The preoperative maximum IOP ranged from 11 to 44 mmHg (median, 28 mmHg, 1 mmHg=0.133 kPa), and the IOP was 10 to 18 mmHg (median, 13 mmHg) at the last follow-up. Two to 4 types of medication were used for glaucoma preoperatively (median, 3), while 0 to 2 types (median, 0) were used at the last follow-up. During the follow-up, 7 cases were completely successful and only one case failed. Intraoperative hemorrhage occurred in two patients, and after effective treatment, the IOP decreased to below 20 mmHg. One patient was found to have an increased IOP with the XEN luminal obstruction, and the XEN drainage tube was recanalized. The IOP was about 10 mmHg at the last follow-up, and no anti-glaucoma drugs were used, but the surgery was assessed as failure by standard. The remaining patients had no other serious complications. Conclusion: This preliminary study shows that the XEN gel drainage may be a safe and effective treatment for patients with glaucoma. (Chin J Ophthalmol, 2021, 57: 679-684).

Rapid and accurate diagnosis of brain abscess caused by Nocardia asiatica with a combination of Ziehl-Neelsen staining and metagenomics next-generation sequencing

BACKGROUND AND PURPOSE

Early and accurate diagnosis is vital in cerebral nocardiosis, a very rare and infectious disease associated with a high mortality rate. Herein, we report a case that a patient with brain abscess was swiftly diagnosed and successfully treated.

METHODS

We report a case of a 61-year-old woman with a brain abscess caused by Nocardia asiatica, diagnosed by a combination of Ziehl-Neelsen staining and metagenomics next-generation sequencing (mNGS).

RESULTS

A 61-year-old woman with left breast cancer resection, diabetes mellitus and a 7-month discontinuous cough and fever was admitted to our hospital. On the third day of hospitalization, she experienced a sudden loss of consciousness and was diagnosed with a brain abscess and a pathological change in cerebral mass on brain magnetic resonance imaging (MRI). Due to the failure of culturing any microorganisms from the pup, the dissected sample from the patient with Ziehl-Neelsen staining tested positive for acid-fast bacilli and was subjected to mNGS. The pathogen was identified as N. asiatica and the patient was treated accordingly with linezolid and trimethoprim-sulfamethoxazole until complete recovery was confirmed by the follow-up cerebral MRI.

CONCLUSIONS

This is the first case report of a brain abscess caused by N. asiatica being swiftly diagnosed by a combination of Ziehl-Neelsen staining and mNGS. This rapid diagnosis allowed us to successfully treat this rare infection.

[Asbestos exposure and asbestos-related malignant diseases:an epidemiological review]

Asbestos has high fire resistance, electrical insulation and thermal insulation. It is an important fire prevention, insulation and insulation material. It is widely used in industrial production and daily life. In 1987, the international agency for research on cancer (IARC) has listed asbestos as a class I carcinogen; in 2012, IARC confirmed that all types of asbestos have carcinogenic effect. By 2019, asbestos has been banned in 66 countries and regions around the world. Asbestos exposure increases the risk of human malignant tumor. Lung cancer and mesothelioma are known asbestos induced tumors. Epidemiological studies also support that asbestos exposure is related to the incidence of malignant tumors in reproductive system, digestive system, urinary system, nasopharynx head and neck. We summarized the epidemiological studies of asbestos induced tumors in order to provide reference for further research.

[A case of Hemolytic anemia caused by subacute lead poisoning]

Lead poisoning is characterized by nervous, digestive and blood system damage, such as neurasthenia, abdominal pain, abdominal distension, jaundice, small cell hypochromic anemia and so on. A case of severe hemolytic anemia caused by subacute lead poisoning was treated in Beijing Chaoyang Hospital Affiliated to Capital Medical University. The main symptoms of the patient were abdominal colic, constipation and hemolytic anemia.

[Research progress of silica-associated autoimmune diseases]

Silicosis is caused by long-term exposure to dust containing crystalline silica. However, silica exposure, which may lead to autoimmune dysfunction, is associated with autoimmune diseases such as rheumatoid arthritis, systemic sclerosis, systemic lupus erythematosus, idiopathic inflammatory myopathy and anti-central granulocyte cytoplasmic antibody associated vasculitis. With silica exposure autoimmune diseases may exist with or without silicosis. This article reviews recent research on silica-associated autoimmune diseases such as the concept, epidemiology, clinical characteristics and potential mechanisms to improve the understanding of the disease and promote the formulation of diagnostic criteria and treatment plans.

[A concise review of telomere and telomerase-related genetic markers in fibrotic lung diseases]

Fibrotic lung diseases are a heterogeneous group of diffuse parenchymal lung diseases caused by various factors. Pulmonary fibrosis is one of the common pathological changes of advanced fibrotic lung diseases. Idiopathic pulmonary fibrosis (IPF) is a chronic progressive fibrotic lung disorder with unknown etiology. IPF mainly affects the elderly that is considered as an aging related disease. Telomeres are specialized structures at the ends of chromosomes. Telomere shortening results in cellular senescence or apoptosis. Telomerase is a ribonucleoprotein complex that maintains telomere length and genome stability. The telomere shortening and mutations in telomere-related genes are associated with incidence and prognosis of pulmonary fibrosis. Here, a concise review of telomere and telomerase-related genomic markers in IPF and other fibrotic lung diseases is written.

[Advances in flavoring-related bronchiolitis obliterans]

Occupational exposure to the diacetyl flavoring may cause bronchiolitis obliterans (BO) in workers. The first case of flavoring-related bronchiolitis obliterans was reported in 2002. Since then, similar cases have been identified among workers in various production industries in some countries and regions. At present, there are no cases reported in China. In order to improve the awareness of the disease and promote the prevention work, this article reviews the research progress of case recognition, risk factors, clinical manifestation and possible pathogenesis.

Performance Assessment on Buffy Coat Examination for Human Granulocytic Anaplasmosis Diagnosis

Introduction/Objective

Anaplasma phagocytophilum is an obligate gram-negative intracellular bacterium that causes human granulocytic anaplasmosis (HGA). The diagnostic tests for HGA include buffy coat examination, culture, PCR, and serology. In our lab, suspected patient will be subjected to buffy coat examination, and the result will be further confirmed with PCR. The aim of the study is to assess the epidemiology of HGA diagnosed at WMC during 06/2014- 08/2019, and as well as the performance accuracy of buffy coat examination as compared to PCR.

Methods

The results of buffy coat examination and in house HGA PCR from 06/2014 to 08/2019 were collected from SoftLAB and SoftMOL, respectively.

Results

A total of 1,057 blood specimens were tested by buffy coat examination from 06/2014-08/2019; among them, 658 specimens were also analyzed by HGA PCR assay (Fig. 1). Positivity for buffy coat examination and PCR was 2.6% and 6.1%, respectively. Overall, using PCR as reference diagnostic method, 42 new HGA cases were identified.

The number of new HGA cases varied among years from 2 to 15, with year of 2017 having the greatest number of total cases (Fig. 2). Further analyzing new HGA cases by months reveal HGA starts in April and ends in December, and peaks at June and July (Fig. 3).

When comparing buffy coat result to PCR, 17 positive buffy coat tests were confirmed positive in PCR test, and 619 negative buffy coat tests were also consistent with negative PCR test result. However, 21 cases which were initially negative in buffy coat examination were positive in PCR tests. On the other hand, 1 positive buffy coat examination case was negative in PCR (table 1). Overall, using PCR as a reference test, the sensitivity and specificity of buffy coat examination are 44.7% and 99.8%, respectively.

Conclusion

Buffy coat examination has high specificity but low sensitivity in detecting HGAcompared to PCR. Low sensitivity is most likely due to variable presence of intracytoplasmic aggregates of HGA in peripheral blood neutrophils and technically incompetency of testing personnel. Overall, it is a good test for laboratory confirmation of clinically suspected HGA cases. We suggest clinicians to add HGA PCR to all the buffy coat examination to avoid missing potential HGA diagnosis. Moreover, more training and competency on testing personnel may improve the sensitivity of buffy coat exam for diagnosis of HGA.

A Comparative Analysis of Immunohistochemical Profile of Primary and Metastatic Endometrial Endometrioid Carcinoma

Introduction/Objective

Beta catenin plays an important role in cancer tumorigenesis and have been found to be associated with metastasis in a variety of tumors. Analyzing TCGA data, we found that 30% of endometrial endometrioid carcinoma cases have beta-catenin mutations. We hypothesize that beta-catenin mutation may be associated with metastasis of endometrial endometrioid carcinoma. ER and PR expression was also compared to determine any changes after metastasis.

Methods

Retrospective institutional review of all endometrial endometrioid carcinoma (192 cases) between 2011 to 2018 was performed, including 149 cases of FIGO grade I, 38 cases of FIGO grade II and 5 cases of FIGO grade III. 19 cases with paired primary and metastatic specimen were identified. Immunohistochemistry staining (IHC) was carried out for ER, PR and beta-catenin.

Results

Median patient age was 56 years. The most common metastatic site was vagina, accounting for 68% of metastasis (14/19), followed by bladder (3/19), lung (2/19) and rectum (1/19). The primary and metastatic carcinoma of all 19 cases exhibit very similar morphology. All of those cases were positive and concordant for ER and PR in primary and metastatic endometrioid carcinoma. On the other hand, nuclear beta-catenin staining caused by mutation was positive in 5 metastatic carcinoma but not in primary carcinoma.

Conclusion

IHC expression of ER and PR remains unchanged between primary and metastatic carcinoma, demonstrating the reliability of ER and PR to confirm the origin of metastatic carcinoma. 26% of the metastatic carcinoma (5/19) exhibit nuclear beta-catenin staining but not in primary carcinoma, suggesting the possible role of beta-catenin in metastasis of endometrial endometrioid carcinoma.

Structural exercise-based intervention for health problems in individuals with autism spectrum disorders: a pilot study

OBJECTIVE

Exercise-based intervention promises to be more effective in a structured framework for individuals with autism spectrum disorders (ASD). The aim of this study was to observe changes in behavior of individuals with ASD by investigating their physical status after the structured exercise-based intervention.

PATIENTS AND METHODS

The exercise intervention integrated an 8-week exercise program that included aerobic, resistive, and neuromuscular exercises. Body composition and the Autism Treatment Evaluation Checklist (ATEC) were evaluated to assess changes after the exercise-based intervention.

RESULTS

After the exercise intervention, the fat mass of individuals with ASD were significantly reduced, and their behavior improved markedly.

CONCLUSIONS

This pilot study demonstrated that individuals with ASD require long-term, structured exercise-based intervention, and that such exercise-based intervention is effective for improving their health.

[Progress in randomized clinical trials of antifibrotic drug nintedanib and pirfenidone]

Pulmonary fibrosis is the terminal manifestation of a variety of interstitial lung diseases. Idiopathic pulmonary fibrosis (IPF) is one of the chronic, progressive, fibrotic lung disease with high incidence and poor prognosis. Nintedanib and pirfenidone are currently marketed anti-pulmonary fibrosis drugs, and their efficacy and safety are recognized in patients with IPF. This article reviews the targets and clinical trials of the two drugs, and provides a basis for the expansion of indications for anti-pulmonary fibrosis drugs.

Linking vein properties to leaf biomechanics across 58 woody species from a subtropical forest

Leaf venations have elements with relatively lower elasticity than other leaf tissue components, which are thought to contribute to leaf biomechanics. A better mechanistic understanding of relationships between vein traits and leaf mechanical properties is essential for ecologically relevant interpretation of leaf structural variations. We investigated 13 major (first to third order) and minor (>third order) vein traits, six leaf mechanical properties and other structural traits across 58 woody species from a subtropical forest to elucidate how vein traits contribute to leaf biomechanics. Across species, vein dry mass density (ρ_v ), total vein dry mass per leaf area (VMA) and minor vein diameter (VD_min ), but not the lower-order vein density (VLA_1•2 ), were positively correlated with leaf force to punch (F_p ) and force to tear (F_t ). Structural equation models showed that ρ_v and VD_min not only contribute to leaf mechanical properties directly (direct pathway), but also had impacts on leaf biomechanics by influencing leaf thickness and leaf dry mass per area (indirect pathway). Our study demonstrated that vein dry mass density and minor vein diameter are the key vein properties for leaf biomechanics. We also suggest that the mechanical characteristics of venations are potential factors influencing leaf mechanical resistance, structure and leaf economics spectrum.

[Risk factors of cirrhosis combined with sarcopenia and their impact on clinical outcomes]

Objective: To study the occurrence of sarcopenia in patients with liver cirrhosis, and to explore their risk factors and impact on clinical outcomes. Methods: 199 hospitalized cases with liver cirrhosis were collected for nutritional risk screening, anthropometric measurement and blood biochemical examination. The body composition analysis was measured based on the skeletal muscle content of the four limbs to calculate the appendicular skeletal muscle mass index (ASMI). Patients were divided into sarcopenia and non-sarcopenia group and the relevant indexes of both groups were compared to screen for factors affecting the occurrence of sarcopenia. During the follow-up of 48 months, the survival and complications of the both groups were compared. Statistical analysis was performed using t-test, χ(2) test and logistic regression analysis in terms of different data. Results: The incidence of sarcopenia in cirrhosis was 36.7%, with the highest prevalence in patients with recurrent hepatic encephalopathy (62.5%), followed by patients with abdominal ascites / pleural effusion (37.6%). The incidence of sarcopenia was significantly higher in those with nutritional risk than in those without nutritional risk (P < 0.05). However, even among those without nutritional risk, 14.8% had combined sarcopenia. The body mass index (BMI), upper arm muscle circumference (AMC), and body cell mass (BCM) of the sarcopenia group were lower than those of the non-sarcopenia group (P < 0.05), and the edema index (ECW/TBW) was higher than the latter (P < 0.05). Multivariate analysis showed that age, gender, BMI, and complications of hepatic encephalopathy were the main influencing factors of cirrhosis combined with sarcopenia (P < 0.05). During the follow-up period, the sarcopenia group had a higher mortality rate than non-sarcopenia goup (P < 0.05), and the incidence of recurrent abdominal ascites/pleural effusion, hepatic encephalopathy, and infection was also significantly elevated (P < 0.05). Conclusion: Sarcopenia is one of the manifestations of malnutrition in patients with liver cirrhosis, which increases the risk of mortality and other complications, and has adverse impact on the clinical outcome. Additionally, older age, male sex, low BMI and recurrent hepatic encephalopathy has higher risk for developing sarcopenia.

[Clinicopathological characteristics, MSI and K-ras gene mutations of double primary malignancies associated with colorectal cancer]

Objective: To investigate the clinicopathological characteristics, MSI and K-ras mutation of double primary malignancies (DPM) associated with colorectal cancer (CRC). Methods: From January 2015 to December 2016, the clinicopathological data of CRC patients treated by surgery in the Affiliated Drum Tower Hospital of Nanjing University Medical School were collected, and the clinical data was analyzed. Multiplex real-time fluorescence quantitative PCR and amplification refractory mutation was performed to identify MSI and K-ras gene mutations. Results: Of all patients with CRC, 5.2% (55/1 066) were DPM. There was no significant difference in the male and female ratio, age, colorectal cancer site, T stage, N stage composition ratio between DPM patients with CRC and patients with single CRC (P>0.05). There were significant difference of TNM stage between the two group (P<0.05). The most frequent location of CRC was the colon in both DPM patients with CRC and patients with single CRC[35.5% (359/1 011) and 41.8% (23/55), respectively]. Of 55 DPM patients with CRC, 48 were metachronous DPM patients, 7 were synchronous DPM patients and 41 were colorectal cancer first. In extracolonic organ, digestive system (23/55) was the most commonly occurring system and stomach (11/55) was the most common lesion. DPM patients with CRC had higher incidence of MSI-H than patients with single CRC (P<0.05). There was no significant difference of K-ras gene mutation between DPM patients with CRC and patients with single CRC (P>0.05). MSI-H and K-ras mutation were present in only 2 patients of DPM patients with CRC. Conclusions: The rectum is the most common lesion site in CRC patients. The stomach is the most common extracolonic organ of DPM patients with CRC. DPM patients with CRC has high risk of MSI-H, but no significant difference in the incidence of K-ras mutation.

Scarless neck endoscopic thyroidectomy via the breast approach: A preliminary report of 45 cases with total or near-total thyroidectomy plus central compartment dissection

Background

There are various endoscopic techniques for thyroid carcinoma dissection but few reports regarding the scarless neck technique and central compartment dissection (CCD) via the breast approach, especially for bilateral CCD are available. In this study, we reported 45 cases with scarless neck endoscopic total or near-total thyroidectomy plus CCD via the breast approach.

Materials and Methods

Forty-five female patients with papillary thyroid carcinoma (PTC) were enrolled in the study, from January 2011 to March 2013. In brief, 5 mm ultrasonic coagulation device (Harmonic Scalpel, HS; Ethicon Endosurgery, USA) was used to perform thyroid vessel management and thyroidectomy. Twenty patients underwent total thyroidectomy and 25 underwent near-total thyroidectomy. CCD was performed in all 45 patients, including 13 with bilateral CCD and 32 with ipsilateral CCD.

Results

The procedure was successful for all 45 patients. Sixteen patients (35.6%) had lymph node metastases in central compartments. Postoperative transient adverse events included voice changes (9 patients) and hypocalcemia (18 patients), including 7 (21.9%) in the unilateral group and 11 (84.6%) in bilateral group. There was no permanent hypocalcemia or recurrent laryngeal nerve (RLN) palsy. None of the case were converted to open surgical procedure. All patients were satisfied with the cosmetic result of the scarless neck endoscopic thyroidectomy (SET). No evidence of residual or recurrent disease was found during a mean follow-up of 22.84 months (range, 12-34 months).

Conclusions

Experienced thyroid surgeons performed the scarless neck endoscopic total or near-total thyroidectomy plus unilateral or bilateral CCD via the breast approach for selected PTC patients. The procedure was safe and feasible with excellent cosmetic results.

A histological study of mouse tissues and water loss following lyophilization

Lyophilization is a practical method for product storage and transportation; it commonly is used in the food and pharmaceutical industries. Lyophilization also is used for preserving biological samples such as serum, plasma and animal tissues. We found that lyophilization does not affect the stability of RNAs and proteins in tissue samples. To investigate histological characteristics, we prepared lyophilized tissues for paraffin sectioning and hematoxylin and eosin (H & E) staining. We also measured water loss from organs during lyophilization. We used immunohistochemistry of frozen brain sections to identify potential protective effects of three concentrations of sucrose, glucose and trehalose against the effects of lyophilization. H & E staining revealed vacuoles in heart, lung, liver, kidney, spleen and brain after lyophilization without pretreatments, especially heart and kidney. We found that 10% solutions of sucrose, glucose and trehalose helped preserve tissue morphology. Immunohistochemistry of frozen brain tissue showed that 10% glucose and 30% sucrose preserved cellular characteristics and immunogenicity following lyophilization. Lyophilization removed > 70% of the water from organs, and lyophilized tissues without protectants were not suitable for histological study. Overall, we found that 10% glucose helped preserve both optimal tissue morphology and immunogenicity of freeze-dried tissue.

[Application of mucosal flap technique in Draf type Ⅱb/Ⅲ frontal sinus surgery]

Draf type Ⅱb/Ⅲ frontal sinus surgery has been widely used in clinical practice. They can obtain a wide operating space and sufficient drainage pathways. However, the mucosa around the frontal sinus ostium was removed during the surgery, resulting in bone exposure, and sinus ostium stenosis or atresia may occur after the operation. In recent years, rhinologists at home and abroad have applied various mucosal flaps to cover the exposed bone around the frontal sinus orifice after Draf Ⅱb/Ⅲ frontal sinus surgery, in order to reduce scar formation and bone hyperplasia along with the incidence of frontal sinus ostium stenosis or atresia after surgery. Satisfactory results have been achieved. The article reviews the application of mucosal flap technique in Draf Ⅱb/Ⅲ frontal sinus surgery, in order to promote the clinical research and technical development of this technique in China.

[Clinical characteristics, treatment and outcome of chronic mercury-related nephrotic syndrome]

Objective: To investigate the etiology, clinical features, treatment and outcome of nephrotic syndrome associated with chronic mercury poisoning. Methods: From June 2013 to April 2018, Beijing Chaoyang Hospital, Capital Medical University received 33 patients with chronic mercury-neutral nephrotic syndrome. The clinical manifestations, laboratory tests, treatment methods, and outcomes were analyzed. Results: Among the 33 patients, 27 patients had mercury exposure due to daily-life contact and the other 6 patients were caused by iatrogenic mercury. The symptom was characterized by typical nephrotic syndrome such as lower extremity edema and proteinuria at first onset. The treatment was based on mercury-removing treatment, 19 cases were treated with mercury removal alone, 16 cases were completely relieved; 10 cases were treated with mercury removal and glucocorticoids, all of which were completely relieved; 4 cases were treated with mercury removal, glucocorticoids and immunosuppressive agents, all complete remission; clinical complete remission rate is about 90.9% (30 cases in total) . Urinary mercury levels decreased the fastest between the first and second courses of mercury treatment, but the total amount of urine protein increased. As the amount of urinary mercury excreted increased, the total amount of urine protein decreased gradually (Z=2.86, P<0.01) . Conclusion: The clinical features of chronic mercury-induced nephrotic syndrome are non-specific, easy to be misdiagnosed and missed. The treatment is mainly treated with mercury removal treatment. The prognosis is good. In severe cases, glucocorticoid therapy can be supplemented.

[Study on the mechanism of serotype conversion of historical isolates of Shigella flexneri]

Objective: The serotype screening of Shigella flexneri from 1934 to 1965 preserved by the National Center for Medical Culture Collections was carried out, and the molecular characteristics of the serotype conversion strains were studied. Methods: Serotyping of Shigella flexneri in this study was conducted by slide agglutination and multiplex PCR, respectively. The gtrⅡ gene sequence alignment and pulsed field gel electrophoresis typing were performed on the serotype conversion strains. Results: Among the 255 strains of Shigella flexneri preserved in CMCC (B) from 1934 to 1965, 79 were carrying gtrⅡ gene, of which 19 strains and 1 strain were agglutinated with the Y serotype and X serotype, respectively, and furthermore, the multiplex PCR assays results showed serotypes 2a and 2b, respectively, and the strains were considered to have serotype conversion. The 20 strains carrying the gtrⅡ gene showed multiple nucleotide mutations. Besides 3 strains of 3 amino acid mutations, the amino acid sequences of the other 17 strains showed a stop codon in advance, resulting in functional inactivation of gtrⅡ. PFGE analysis revealed that the similarity between the serotype Y strain carrying the gtrⅡ gene and the serotype 2a strain was 75.8%-100%, and the similarity between the serotype X strain carrying the gtrⅡ gene and the serotype 2b strain was 81.6%-100%. Conclusion: Mutations in the gtrⅡ gene are more complicated in serotype-transforming Shigella flexneri serotype Y or X strains. Molecular typing suggests that the serotype-transforming Shigella flexneri serotype Y or X strains may be derived from the Shigella flexneri serotype 2a or 2b, and advance the serotype conversion to 1949.