The detection rate of carbapenem-resistant nontyphoidal Salmonella (NTS) is relatively low. However, carbapenem-sensitive and carbapenem-resistant Salmonella enterica serovar Typhimurium ( S. enterica serovar Typhimurium) were isolated from a clinical outpatient within a span of 10 days, named 1104–65 and 1104–75. We aimed to reveal the mechanism of carbapenem resistance in S. enterica serovar Typhimurium isolates in this case. The resistance phenotype of S. enterica serovar Typhimurium was analyzed by the VITEK-2 Compact equipment and Kirby-Bauer disc diffusion method. Whole-genome sequencing was used to analyze the serotype, ST type, genetic relationship, resistance genes, plasmid replicon, the genetic environment of bla _NDM-5 , and the characteristics of IncFII plasmid carrying bla _NDM-5 in S. enterica serovar Typhimurium. The transferability of the IncFII plasmid carrying bla _NDM-5 was verified by the conjugation assay and PCR. The serotypes of both NTS are S. enterica serovar Typhimurium, belonging to ST34. Single nucleotide polymorphisms analysis showed that they were the same clone. A conjugative IncFII plasmid pIncFII-NDM5 with transferability was detected in isolate 1104–75, which harboring the bla _NDM-5 gene was the primary mechanism responsible for mediating carbapenem resistance in S. enterica serovar Typhimurium. The genetic environment of bla _NDM-5 on pIncFII-NDM5 is “IS 26 -ΔIS 3000 -IS 5 -ΔIS Aba125-bla _NDM-5 - ble _MBL - trpF-dsbC -cutA -IS 26 ”, which was confirmed as a novel structure not previously reported in the NCBI database. Although the mechanism is rarely reported in NTS, the prevalence of IncFII plasmid pIncFII-NDM5 will pose a great threat to the clinical treatment of S. enterica serovar Typhimurium. Meanwhile, the coexistence of bla _CTX-M-55 , qnrS1 , bla _NDM-5 , and mph(A ) in S. enterica serovar Typhimurium ST34 warrants additional attention. IMPORTANCE: In this study, an IncFII plasmid pIncFII-NDM5 carrying bla _NDM-5 was found in carbapenem-resistant Salmonella enterica serovar Typhimurium ( S. enterica serovar Typhimurium), which has conjugative transferability and carried bla _NDM-5 , ble _MBL , mph(A ), and bla _TEM-1 four resistance genes that can mediate resistance to multiple antibiotics including cephalosporins, beta-lactamase inhibitor combinations, carbapenems, and macrolides. Phylogenetic analysis showed that 1104–65 and 1104–75 were closely related to other S. enterica serovar Typhimurium in this area. The above-mentioned S. enterica serovar Typhimurium chromosome carries bla _CTX-M-55 , qnrS1 , and tet(A ) genes, so the antibiotic resistance of isolates will be further enhanced after obtaining the pIncFII_NDM5-like plasmid. Meanwhile, we discovered a novel genetic structure of bla _NDM-5 mediated by the IS 26 composite transposon, which will expand our understanding of the emergence and spread of carbapenem-resistance genes. Altogether, the presence of the IncFII plasmid pIncFII-NDM5 further underscores the need for vigilant surveillance and appropriate infection control measures to mitigate the impact of carbapenem-resistant S. enterica serovar Typhimurium in clinical settings.

The American Thyroid Association (ATA) proposed a new risk classification for hereditary medullary thyroid carcinoma (MTC) in 2015. This study aimed to assess whether the new guidelines are suitable for the Chinese population, and reported our experience on prophylactic thyroidectomy. A total of 73 patients from 22 families were screened as rearranged during transfection (RET) mutation carriers from 2010 to 2016 in Cancer Hospital, Chinese Academy of Medical Science; the medical history for each patient was collected. Based on the initial treatment, we identified the risk factors for poor prognosis by univariate and multivariate logistic regression. Then, 4 RET mutation carriers were enrolled for prophylactic thyroidectomy, and their pathological data and follow-up outcomes were recorded. In univariate and multivariate logistic regression analyses, age at initial surgery and risk classification were significant risk factors for stage III/IV hereditary MTC at initial diagnosis. The likelihood was increased by 11.6% per year of age at initial surgery [95% confidence interval (95% CI), 1.040-1.198; P=0.002). It was 7.888 times more likely to have III/IV stage disease for ATA highest risk patients, compared to ATA moderate risk individuals (95% CI, 1.607-38.717; P=0.003). Postoperative pathological results showed all 4 multiple endocrine neoplasia type 2A (MEN2A) patients had C-cell hyperplasia (CCH); multifocal malignancies were detected in 3 of them. All 4 patients were cured biochemically, and none developed permanent hypoparathyroidism. In Chinese individuals, hereditary MTC aggressiveness is in line with the new ATA risk classification. Germline RET gene mutation carriers should undergo prophylactic thyroidectomy according to basal serum calcitonin levels.

Background: Medullary thyroid cancer (MTC) can only be cured by surgery, but the management of lateral lymph nodes is controversial, especially for patients with cN0+cN1a. To address this challenge, we developed a multivariate logistic regression model to predict lateral lymph node metastases (LNM).Methods: We retrospectively collected clinical data from 124 consecutive MTC patients who underwent initial surgery at our institution. The data of 82 patients (from 2010 to 2018) and 42 patients (from January 2019 to November 2019) were used as the training set for building the model and as the test set for validating the model, respectively.Results: In the training group, the multivariate analyses indicated that male and MTC patients with higher preoperative basal calcitonin levels were more likely to have lateral LNM (P = 0.007 and 0.005, respectively). Multifocal lesions and suspected lateral LNM in preoperative ultrasound (US) were independent risk factors (P = 0.032 and 0.002, respectively). The identified risk factors were incorporated into a multivariate logistic regression model to generate the nomogram, which showed good discrimination (C-index = 0.963, 95% confidence interval [CI]: 0.9286–0.9972). Our model was validated with an excellent result in the test set and even superior to the training set (C-index = 0.964, 95% CI: 0.9121–1.000).Conclusion: Higher preoperative basal calcitonin level, male sex, multifocal lesions, and lateral lymph node involvement suspicion on US are risk factors for lateral LNM. Our model and nomogram will objectively and accurately predict lateral LNM in patients with MTC.