Relationship between the Metabolic Associated Fatty Liver Disease and Endometrial Thickness in Postmenopausal Women: A Cross-sectional Study in China.

Objectives: To determine the relationship between the endometrial thickness (ET) and metabolic associated fatty liver disease (MAFLD) in the postmenopausal women who have a comprehensive health examination. Methods: This was a population-based, retrospective observational study of the prevalence of MAFLD in 8594 postmenopausal women with different ET in the Quality Control Center of Health Examination in Chongqing, China. Binary and multivariable logistic regression analyses were used to obtain odds ratios and 95% confidence intervals for patients of different ET with MAFLD after adjusting for age. Results: The incidences of MAFLD were 28.6% (1352), 30.3% (1058), 34.9% (133) in postmenopausal women with ET of < 3 mm, 3 mm ≤ & < 5 mm, and ≥ 5 mm, respectively. Compared with a baseline ET of less than 5.0 mm, the risk of MAFLD in patients with ET of ≥5.0 mm is higher (OR=1.291, 95% CI: 1.041-1.603, P<0.05). After adjustment for age, a statistically significant positive correlation was still observed. The increased prevalence of MAFLD in patients with ET of 3 mm ≤ &<5 mm (OR=1.110, 95% CI: 1.008-1.223) and ≥5 mm (OR=1.383, 95% CI: 1.109-1.724) achieved statistical significance, respectively. In addition, multiple logistic analyses controlling for age also confirmed the finding of positive correlation among body mass index (BMI) and ET. Conclusion: Our results suggest that there is a positive correlation between MAFLD and ET in postmenopausal women. In addition, increased BMI is also associated with an increased risk of thickened endometrium.

Relationship between mammographic calcifications and the clinicopathologic characteristics of breast cancer in Western China: a retrospective multi-center study of 7317 female patients.

BACKGROUND AND PURPOSE: Limited information is available regarding the correlations between mammographic calcifications and the epidemiological features of patients with breast cancer living different lifestyles in Western China. Thus, this study aimed to investigate the relationship between mammographic calcifications and the epidemiological characteristics of female patients with breast cancer in Western China. METHODS: This was a hospital-based, retrospective, multi-center epidemiological study of patients with breast cancer. Using the Western China Clinical Cooperation Group (WCCCG) database, we obtained the records of 7317 patients (with mammographic data) diagnosed with breast cancer between March 2011 and June 2016. These patients were divided into Groups I (mass alone) and II (mass combined with calcification), and their clinical and pathological data were compared. RESULTS: A total of 4211 patients were enrolled in Group I, and 3106 patients were enrolled in Group II. The tumors in Group II were more likely to be larger (P < 0.0001), higher grade (P = 0.0029), estrogen receptor (ER)+/progesterone receptor (PR)- (P = 0.0319), and human epidermal growth factor receptor 2 (HER-2)-positive (P < 0.0001), and to have axillary lymph node metastasis (P = 0.0033) than those in Group I. Regarding treatment, patients in Group II were more likely to have undergone chemotherapy (P = 0.0108) and anti-HER2 therapy (P = 0.0102), whereas patients in Group I were more likely to have undergone endocrine therapy (P < 0.0001). CONCLUSIONS: In conclusion, mammographic calcifications in tumors were associated with distinct clinicopathologic characteristics and aggressive treatments.

An Adjustable-Traction Technique for Correction of Inverted Nipples.

BACKGROUND: Inverted nipples are a common problem in female patients. This deformity impairs the function and appearance of the breast and may cause psychological distress. Existing correctional techniques may result in nipple necrosis, recurrence, infection, and scarring. In this study, we evaluated the efficacy of a minimally invasive inverted nipple correction method involving an adjustable-traction device designed by the authors. METHODS: All patients who underwent correction of inverted nipples at the authors' hospital from April 2003 to March 2014 were retrospectively evaluated. Patients were divided into 2 groups according to the correction technique. In group A, 41 nipples in 25 patients underwent traditional (conventional) surgical correction. In group B, 74 nipples in 40 patients underwent continuous traction using our traction device for 2 to 4 months. All patients were followed up for 6 to 12 months postoperatively (group A) or after finish the course of therapy (group B). Complications and patient satisfaction were compared between the groups. RESULTS: No infection occurred in either group. In group A, 9 patients were dissatisfied, and a severe complication occurred in 1 nipple. In group B, all inverted nipples were corrected, and nipple inversion recurred in 2 patients; repeat traction produced a good outcome. Group B had fewer complications and higher patient satisfaction than group A. CONCLUSIONS: This adjustable continuous-traction technique provided better correction of inverted nipples with fewer complications and higher patient satisfaction than did traditional surgical correction. This safe, simple, effective, minimally invasive technique is suitable for correction of various types of inverted nipples.

Bilateral chylothorax following left supraclavicular lymph node dissection for breast cancer: one case report and literature review.

Chylothorax is a rare complication of neck dissection, and bilateral chylothorax is even rarer. However, both are potentially serious and sometimes life-threatening, especially those that are associated with left neck dissection for head and neck neoplasms. We report one case of bilateral chylothorax following left supraclavicular dissection for breast cancer. This case was treated successfully with a new conservative management approach.

Ku counteracts mobilization of PARP1 and MRN in chromatin damaged with DNA double-strand breaks.

In mammalian cells, the main pathway for DNA double-strand breaks (DSBs) repair is classical non-homologous end joining (C-NHEJ). An alternative or back-up NHEJ (B-NHEJ) pathway has emerged which operates preferentially under C-NHEJ defective conditions. Although B-NHEJ appears particularly relevant to genomic instability associated with cancer, its components and regulation are still largely unknown. To get insights into this pathway, we have knocked-down Ku, the main contributor to C-NHEJ. Thus, models of human cell lines have been engineered in which the expression of Ku70/80 heterodimer can be significantly lowered by the conditional induction of a shRNA against Ku70. On Ku reduction in cells, resulting NHEJ competent protein extracts showed a shift from C- to B-NHEJ that could be reversed by addition of purified Ku protein. Using a cellular fractionation protocol after treatment with a strong DSBs inducer followed by western blotting or immunostaining, we established that, among C-NHEJ factors, Ku is the main counteracting factor against mobilization of PARP1 and the MRN complex to damaged chromatin. In addition, Ku limits PAR synthesis and single-stranded DNA production in response to DSBs. These data support the involvement of PARP1 and the MRN proteins in the B-NHEJ route for the repair of DNA DSBs.

Aberrant promoter CpG methylation and its translational applications in breast cancer.

Breast cancer is a complex disease driven by multiple factors including both genetic and epigenetic alterations. Recent studies revealed that abnormal gene expression induced by epigenetic changes, including aberrant promoter methylation and histone modification, plays a critical role in human breast carcinogenesis. Silencing of tumor suppressor genes (TSGs) by promoter CpG methylation facilitates cells growth and survival advantages and further results in tumor initiation and progression, thus directly contributing to breast tumorigenesis. Usually, aberrant promoter methylation of TSGs, which can be reversed by pharmacological reagents, occurs at the early stage of tumorigenesis and therefore may serve as a potential tumor marker for early diagnosis and therapeutic targeting of breast cancer. In this review, we summarize the epigenetic changes of multiple TSGs involved in breast pathogenesis and their potential clinical applications as tumor markers for early detection and treatment of breast cancer.

HYAL1 overexpression is correlated with the malignant behavior of human breast cancer.

Extracellular matrix (ECM) is closely correlated with tumor cell growth, proliferation, metastasis and angiogenesis, etc. Hyaluronic acid (HA) is a component of the ECM, and hyaluronidase (HAase) is a HA-degrading endoglycosidase. Levels of HAase are elevated in many cancers. Hyaluronidase-1 (HYAL1) is the major tumor-derived HAase. In this study, we detected HYAL1 expression levels in breast cancer cells and tissues, and measured the amount HAase activity in breast cancer cells. Compared with nonmalignant breast cell line HBL-100 and normal breast tissues, HYAL1 were overexpressed in breast cancer cell lines MDA-MB-231, MCF-7, invasive duct cancer tissues and metastatic lymph nodes, respectively. Accordingly, the amount HAase activity in MDA-MB-231 and MCF-7 was higher than that in HBL-100. In addition, knockdown of HYAL1 expression in MDA-MB-231 and MCF-7 cells resulted in decreased cell growth, adhesion, invasion and angiogenesis potential. Meantime, the HYAL1 knockdown markedly inhibited breast cancer cell xenograft tumor growth and microvessel density. Further studies showed that the HYAL1, HYAL2 and HA were elevated in breast cancer, and HYAL1 could downregulate HA expression. In conclusion, HYAL1 may be a potential prognostic marker and therapeutic target in breast cancer.

Long-term anti-inflammatory diet in relation to improved breast cancer prognosis: a prospective cohort study.

Inflammation-modulating nutrients and inflammatory markers are established cancer risk factors, however, evidence regarding the association between post-diagnosis diet-associated inflammation and breast cancer survival is relatively sparse. We aimed to examine the association between post-diagnosis dietary inflammatory index (DII®) and risks of all-cause and breast cancer-specific mortality. A total of 1064 female breast cancer survivors in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening (PLCO) Trial prospective cohort, were included in this analysis if they had completed the diet history questionnaire (DHQ). Energy-adjusted DII (E-DIITM) scores were calculated based on food and supplement intake. Cox regression and competing risk models were used to estimate multivariable-adjusted hazards ratios (HRs) and 95% confidence intervals (95% CIs) by E-DII tertile (T) for all-cause and breast cancer-specific mortality. With median follow-up of 14.6 years, there were 296 (27.8%) deaths from all causes and 100 (9.4%) breast cancer-specific death. The E-DII was associated with all-cause mortality (HR T3 vs T1, 1.34; 95% CI, 1.01-1.81; P trend, 0.049, Table 2) and breast cancer mortality (HR T3 vs T1, 1.47; 95% CI, 0.89-2.43; P trend, 0.13; multivariable-adjusted HR for 1-unit increment: 1.10; 95% CI: 1.00-1.22). Non-linear positive dose-response associations with mortality from all causes were identified for E-DII scores (P non-linearity < 0.05). The post-diagnosis E-DII was statistically significantly associated with mortality risk among breast cancer survivors. Long-term anti-inflammatory diet might be a means of improving survival of breast cancer survivors.

[The effects of shRNA-CXCR4 on breast cancer cells migration and invasion].

OBJECTIVE: To study the effect of shRNA-CXCR4 on human breast cancer cells migration and invasion. METHODS: Through knockdown CXCR4 by shRNA, the CXCR4 mRNA expression and protein expression were examined with RT-PCR and Western blot separately. The matrigel penetrating ability of human breast cancer cells was examined in vitro experiments. RESULTS: The CXCR4 mRNA express and its protein express decreased significantly in MCF-7, MDA-MB-231 and MDA-MB-435s breast cancer cells (P<0.05). The invasive ability of human breast cancer cells was significantly decreased (P<0.05). CONCLUSION: through knockdown CXCR4 by shRNA, the invasive ability of human breast cancer cells can be inhibited obviously.

Clinicopathologic and Prognostic Significance of Body Mass Index (BMI) among Breast Cancer Patients in Western China: A Retrospective Multicenter Cohort Based on Western China Clinical Cooperation Group (WCCCG).

INTRODUCTION: Clinicopathologic and prognostic significance of body mass index (BMI) in breast cancer (BC) patients remained conflicting. We aimed to investigate and modify the impact of BMI on clinicopathological significance and survival in western Chinese BC patients. MATERIALS AND METHODS: 8,394 female BC patients from Western China Clinical Cooperation Group (WCCCG) between 2005 and 2015 were identified. Multivariable logistic regression and Cox proportion hazard regressions were used to examine the difference of clinicopathologic and survival characteristics between BMI categories. RESULTS: For the premenopausal, overweight and obese (OW) patients tended to have large tumor size (>5cm) (odds ratio [OR], 1.30, P<0.01) and triple-negative BC (OR, 1.31; P=0.01) compared with normal weight (NW) patients. Premenopausal underweight (UW) patients had a significantly higher risk of HER2 positive (OR, 1.71; P=0.02) and distant metastasis (OR, 2.59; P=0.01). For postmenopausal patients, OW patients showed higher risks of large tumor size (>5cm) (OR, 1.46; P=0.01), nuclear grade III (OR, 1.24; P=0.04), and lymphovascular invasion (OR, 1.46; P=0.01) compared with NW patients. An "U" shaped relationship between BMI and DFS was found (UW versus NW, adjusted hazard ratio (HR), 2.80, P<0.001; OW versus NW, adjusted HR, 1.40, P=0.02), whereas no significant difference of disease-free survival (DFS) between OW and NW premenopausal patients (adjusted HR=1.34, P=0.18) was revealed. CONCLUSION: We concluded that UW and OW were associated with aggressively clinicopathological characteristics, regardless of menopausal status. An "U" shaped association of BMI and DFS was revealed, and no significant difference of DFS between OW and NW in postmenopausal subgroup was revealed.

Expression of livin and vascular endothelial growth factor in different clinical stages of human esophageal carcinoma.

AIM: To investigate the role of livin and vascular endothelial growth factor (VEGF) in human esophageal carcinoma, and analyze its relationship to clinical stages. METHODS: Expression of livin in fresh esophageal cancer tissues was detected by immunohistochemistry (IHC), Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR), and VEGF by Western blotting and RT-PCR. All statistical analyses were performed by SPSS version 11.0. RESULTS: Livin positivity was also significantly correlated with tumor stages, increasing with tumor progression. Expression of livin and VEGF increased with the process of esophageal carcinoma. In the fourth clinical stage, expression of livin and VEGF was the most significant. Expression of Livin was positively correlated with VEGF. CONCLUSION: Over-expression of livin and VEGF contributes to the pathogenesis of esophageal carcinoma.

The expression and biological function of the PHF2 gene in breast cancer.

PHD Finger Protein 2 (PHF2), as a protein code and a transcription regulatory gene, is a member of the Jumonji-C domain (JmjC). PHF2 is located at human chromosome 9q22.31 and is frequently decreased in various malignancies. However, the definite role of PHF2 in breast cancer remains unclear. To detect the expression and function of PHF2 in breast cancer, a q-PCR assay was used to detect the mRNA expression of PHF2 in breast cancer cell lines and paired breast cancer tissues, and immunohistochemistry was used to test the protein expression in breast cancer tissues and adjacent tissues. In addition, an adenovirus vector system was utilized to upregulate the expression of PHF2 in breast cancer cells. In our study, we found that PHF2 was down-expressed in breast cancer on both the mRNA and protein levels and the low expression of PHF2 was significantly associated with lymph node metastasis, Ki67 positive rate, ER negative expression and poor prognosis in breast cancer patients. The ectopic expression of PHF2 obviously inhibited the proliferation of breast cancer cell lines and the growth of xenograft tumors. Due to the tumor suppressor signature of PHF2 in breast cancer, we have reasons to believe that it could be a promoting marker and target for the prognosis and therapy of breast cancer.

Predictors of internal mammary lymph nodes (IMLN) metastasis and disease-free survival comparison between IMLN-positive and IMLN-negative breast cancer patients: Results from Western China Clinical Cooperation Group (WCCCG) database (CONSORT).

Limited studies performed a comprehensive assessment of risk factors for internal mammary lymph nodes (IMLN) metastasis, and disease-free survival (DFS) difference between IMLN-positive and IMLN-negative breast cancer (BC) patients undergoing IMLN dissection and systemic therapies was not clear.A retrospective study included 1977 BC patients from Western China Clinical Cooperation Group between January 2005 and December 2012. The impact of clinicopathological factors on the occurrence of IMLN metastasis was assessed in univariate and multivariate logistic regression analyses, and a nomogram (model) was constructed to predict the IMLN status. DFS difference was evaluated in univariate and multivariate Cox regression analyses between IMLN-negative and IMLN-positive patients, and univariate analysis was performed to compare DFS between individuals with high and low IMLN metastasis risk defined by proposed nomogram.Of 1977 enrolled patients, 514 cases underwent IMLN dissection and 1463 cases did not undergo IMLN irradiation or dissection. We found that initial disease symptoms and signs, mammographic calcification, tumor site, number of positive axillary lymph nodes (ALNs), American Joint Committee on Cancer pT stage, and human epidermal growth factor receptor 2 status were associated with IMLN metastasis (all P < .05). Those variables were included in nomogram, whose predictive ability was better than that of ALN classification (area under the curve: 0.82 vs 0.76, P < .001). Univariate cox proportional hazards model indicated that better DFS was observed in IMLN-negative patients than IMLN-positive group (hazard ratio [HR] = 1.87, 95% confidence interval [CI] = 1.05-3.34; P = .04), whereas no significant differences in DFS (HR = 0.99, 95% CI = 0.49-2.00; P = .97) were found after adjusting patient-, disease-, and treatment-related factors.Nipple inversion, mammographic calcification, larger tumor size, medial tumor site, negative HER-2 status, and more positive ALNs are independent risk factors for IMLN metastasis, and the individualized nomogram is a feasible tool to predict the status of IMLN. Equivalent DFS was found between positive and negative IMLN patients who all accepted IMLN dissection and systemic therapies.

Clinicopathologic Factors Related to the Histological Tumor Grade of Breast Cancer in Western China: An Epidemiological Multicenter Study of 8619 Female Patients.

BACKGROUND AND PURPOSE: Breast cancer is now recognized as a clinically heterogeneous disease with a wide spectrum of epidemiological and clinicopathologic features. We aimed to evaluate whether epidemiological and clinicopathologic features are associated with the histological tumor grade of breast carcinomas in Western China. METHODS: We retrospectively collected data from the Western China Clinical Cooperation Group and assessed associations between clinicopathologic factors and histological tumor grade in 8619 female breast cancer patients. Patients were divided into two groups: Group I (tumor grade I/II) and Group II (tumor grade III). Univariable analysis and multivariable logistic regression models were used to analyze the relationships between clinicopathologic factors and tumor grade. RESULTS: Patients presenting with positive axillary lymph nodes, large tumor size (>2 cm), lymphovascular invasion, hormone receptor negativity, human epidermal growth factor receptor 2 (HER-2) positivity, and triple negativity tended to have an increased risk of a high tumor grade. However, the number of pregnancies or births was inversely correlated with the risk of a high tumor grade. In addition, patients presenting with grade III tumors were more likely to receive aggressive treatment, such as adjuvant chemotherapy, anti-HER-2 therapy, and level III axillary lymph node dissection. CONCLUSIONS: Our results suggested that several clinicopathologic factors were associated with high tumor grade of breast cancer patients in Western China.

[A follow-up study about 52 cases of atypical lobular hyperplasia and lobular carcinoma in situ of the breast].

OBJECTIVE: To evaluate the biological behavior and treatment method for the breast atypical lobular hyperplasia (ALH) and breast lobular carcinoma in situ (LCIS). METHODS: Seventeen cases of ALH and thirty-five cases of LCIS were reviewed from July 1982 to January 1996. All cases were followed by physical examination, mammography and B-ultrasound for an average of 146.6 months (range, 3 - 257 months). RESULTS: Most cases of ALH and LCIS occurred before menopause (about 69.2%). Fifty-two cases of ALH and LCIS were occasionally verified pathologically after surgery for benign diseases. The microcalcification with ALH and LCIS had been detected in 25 cases, accounted for 48.1%. Eight cases of ALH/LCIS became invasive carcinoma. There were 5 cases in the same breast, 3 cases in the contralateral breast; The subsequent breast cancer occurred longer than nine years after ALH/LCIS was diagnosed. The family history of breast carcinoma and ovary carcinoma occurred in 4 cases of breast carcinoma, accounted for 50%, but it was no significant (P > 0.05). Also, there was no difference between LCIS and ALH, which occurred the breast carcinoma (P > 0.05). CONCLUSION: The excisional biopsy might be necessary to ALH and LCIS.

Correlation study on chromogranin A genetic polymorphism and prognosis of critically ill patients.

OBJECTIVE: The objective was to investigate the correlation between single nucleotide polymorphism (SNP) of chromogranin A (CHGA) and prognosis of critically ill patients. METHODS: We screened 357 critically ill patients consecutively admitted to our intensive care unit. The -89/-415/-462 SNP locus in the promoter region and the +9559/+9578/+9590/+9611 SNP locus in exon 7 coding of CHGA were genotyped by polymerase chain reaction and DNA sequencing technology. Subsequently, the correlation between genotype and prognosis of patients was analyzed. RESULTS: (1) Three hundred critically ill Chinese Han patients were enrolled in the study. CHGA-415/-462/+9559/+9611 SNPs were polymorphically distributed. Phenotypes of the 4 SNPs were shown not to be in linkage disequilibrium, and there were no significant differences in the minor allele frequencies (MAFs) of the 4 SNPs between participants of this study and healthy people in Asia. (2) The CHGA-415 T/C MAF of the nonsurvival group was significantly higher than that of the survival group (MAF 0.3813 and 0.2864, respectively; P=.026). Survival analysis showed that there were significant differences between the CHGA-415 T/C mutation group (including TC and CC genotypes) and the wild-type group (TT genotype) (log rank=8.887, P=.003). The mortality in the mutant group was significantly higher than that in the wild-type group (0.3333 and 0.1852, respectively; P=.004). (3) Binary logistic analysis showed that CHGA-415 T/C polymorphism was an independent risk factor for the mortality of critically ill patients (odds ratio, 2.286; 95% confidence interval, 1.165-4.484; P=.016). CONCLUSIONS: Critically ill patients with CHGA-415 T/C mutant genotype display higher 30-day mortality than those with the wild-type group. CHGA-415 T/C polymorphism is an independent risk factor of poor prognosis in critically ill Chinese Han patients.

Clinical study on the relationship between hepatitis B virus infection and risk of breast cancer: a large sized case-control and single center study in southwest of China.

PURPOSE: Chronic hepatitis C virus (HCV) infection is reported to be associated with early-onset breast cancer, while, as a hepadnavirus, hepatitis B virus(HBV) infection is more common than HCV in China. In this article, it is aimed to study the relationship between HBV infection and risk of breast cancer in China. METHODS: The clinical data of 2452 cases of initially diagnosed breast cancer and 1926 cases of benign breast disease (as controls) with the consecutive reports of HBV serological markers and liver function tests, available in the Electronic Medical Records of the Breast Cancer Center of Chongqing, the southwest of China, from January 2011 to March 2015, were collected for analysis. RESULTS: The average age of the initially diagnosed breast cancer patients was 50.3±11.3 years with the age peaking about 40- 49yeaers (39.7%). The positive rate (8.2%) of hepatitis B surface antigen in breast cancer patients was relatively higher than that (7.8%) in controls (P>0.05). While, the positive rate (66.4%)of hepatitis B core antibody in breast cancer patients was significantly higher than that (53.7%) in controls (P<0.05), so were the similar results in the age groups of 40-49 years, after multiple layer analysis stratified by age and compare HBV markers adjusting age with binary logistic regression. Meanwhile, the status of albumin, aminotransferase and aspartate transaminase (41.4 g/L, 22.9 U/L, 22.0 U/L) in breast cancer patients were significantly poorer than those (44.1 g/L,16.8 U/L, 19.2 U/L) in controls (P<0.05). CONCLUSIONS: Exposure to HBV infection may be a risk factor for breast cancer and may be also related to the earlier age onset of breast cancer (peaked around 40-49 years) among Chinese females.

Overexpression of sphingosine kinase 1 is predictive of poor prognosis in human breast cancer.

Sphingosine kinase 1 (SPHK1) is a bioactive lipid mediator that has been identified as a biomarker in various cancers and is considered to play an important role in tumor progression. In the present study, the expression level of SPHK1 was examined in breast cancer clinical specimens, and its association with patient survival was investigated to clarify the clinical significance of SPHK1 in breast cancer. SPHK1 mRNA expression was increased in breast cancer tissues compared with that in matched adjacent breast tissues in 19 of 32 paired tissue specimens (59.4%). Immunohistochemical analysis of 122 breast cancer cases revealed that the expression levels of SPHK1 were upregulated in 64 tumor tissues (52.5%), and increased expression levels of the protein were significantly associated with the presence of lymph node metastasis (P=0.0016), number of positive lymph nodes (P=0.0268) and presence of distant metastasis (P=0.0097). Increased SPHK1 protein expression was also associated with human epidermal growth factor receptor 2 status (P=0.0100), initial symptoms (P=0.0025) and tumor location (P=0.0457). Patients with increased SPHK1 protein expression had shorter overall survival and disease-free survival times compared with patients with lower SPHK1. Univariate and multivariate analyses indicated that high SPHK1 expression may be a poor prognostic factor. These results indicated that SPHK1 may perform an important role in breast cancer and may be a predictive factor in patients with breast cancer.

Prevalence of ST1193 clone and IncI1/ST16 plasmid in E-coli isolates carrying blaCTX-M-55 gene from urinary tract infections patients in China.

To study molecular epidemiology of CTX-M-55-carrying Escherichia coli isolates from urinary tract infections (UTIs) in China. 111 blaCTX-M-55-positive E.coli isolates from UTIs patients in China were studied. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to analyze the homologies among the strains. Conjugation experiments, S1nuclease PFGE and PCR analysis were performed to characterize plasmids harboring blaCTX-M-55 and their genetic environment. 111 isolates were clustered into 86 individual pulsotypes and three clusters by PFGE. Fifty-five (49.5%) of the isolates belonged to 8 STs. Most of the ST1193 isolates belonged to one PFGE cluster. Transconjugants (n = 45) derived from randomly selected blaCTX-M-55 donors (n = 58), were found to contain a single 90-kb conjugative plasmid, which mainly belonged to the IncI1 groups (34, 76%). Among the IncI1 plasmids, the blaCTX-M-55/IncI1/ST16 predominated (23/34, 68%). The blaTEM-1 and aac (3')-II genes were frequently detected on the IncI1 plasmids, and the insertion of ISEcp1 or IS26 was observed at the 48 bp or 45 bp upstream of the start codon of blaCTX-M-55 gene. The dissemination of blaCTX-M-55 gene among E. coli UTI isolates, appeared to be due to both the major clonal lineage of ST1193 and the horizontal transfer of epidemic plasmid IncI1/ST16.