Emergence and mechanism of carbapenem-resistant Escherichia coli in Henan, China, 2014.

The emergence and dissemination of carbapenem-resistant Escherichia coli (E. coli) strains is a main risk for global public health, but little is known of carbapenemase producing E. coli in Henan, China. The study was undertaken to investigate the prevalence and mechanism of carbapenem-resistant E. coli strains in a hospital in Xinxiang, Henan, China, 2014. A total of 5 carbapenemase-producing E. coli strains were screened from 1014 isolates. We found that they were all resistant to meropenem and imipenem. Amikacin showed the best sensitivity, with gentamicin coming up next. The positive rate of blaNDM was 80% (4/5). The sequencing results showed that two isolates belonged to blaNDM-1 whereas other 2 isolates carried the blaNDM-5. Other carbapenemase genes including blaIMP,blaVIM, blaKPC and blaOXA-48 were not detected. The blaCTX-M-15,blaTEM-1,sul2, aad, and aac(6")-Ib-cr were also detected. MLST analysis showed that NDM-producing E. coli were sporadic. Conjugation test indicated blaNDM could be transferred. In conclusion, the blaNDM was the principal resistance mechanism of carbapenem-resistant E. coli in the hospital, Henan, China.

Novel Common Variants Associated with Obesity and Type 2 Diabetes Detected Using a cFDR Method.

Genome-wide association studies (GWASs) have been performed extensively in diverse populations to identify single nucleotide polymorphisms (SNPs) associated with complex diseases or traits. However, to date, the SNPs identified fail to explain a large proportion of the variance of the traits/diseases. GWASs on type 2 diabetes (T2D) and obesity are generally focused on individual traits independently, and genetic intercommunity (common genetic contributions or the product of over correlated phenotypic world) between them are largely unknown, despite extensive data showing that these two phenotypes share both genetic and environmental risk factors. Here, we applied a recently developed genetic pleiotropic conditional false discovery rate (cFDR) approach to discover novel loci associated with BMI and T2D by incorporating the summary statistics from existing GWASs of these two traits. Conditional Q-Q and fold enrichment plots were used to visually demonstrate the strength of pleiotropic enrichment. Adopting a cFDR nominal significance level of 0.05, 287 loci were identified for BMI and 75 loci for T2D, 23 of which for both traits. By incorporating related traits into a conditional analysis framework, we observed significant pleiotropic enrichment between obesity and T2D. These findings may provide novel insights into the etiology of obesity and T2D, individually and jointly.

Resting heart rate as a marker for identifying the risk of undiagnosed type 2 diabetes mellitus: a cross-sectional survey.

BACKGROUND: Fast resting heart rate might increase the risk of developing type 2 diabetes mellitus (T2DM). However, it is unclear whether resting heart rate could be used to predict the risk of undiagnosed T2DM. Therefore, the purposes of this study were to examine the association between resting heart rate and undiagnosed T2DM, and evaluate the feasibility of using resting heart rate as a marker for identifying the risk of undiagnosed T2DM. METHODS: A cross-sectional survey was conducted. Resting heart rate and relevant covariates were collected and measured. Fasting blood samples were obtained to measure blood glucose using the modified hexokinase enzymatic method. Predictive performance was analyzed by Receiver Operating Characteristic (ROC) curve. RESULTS: This study included 16, 636 subjects from rural communities aged 35-78 years. Resting heart rate was significantly associated with undiagnosed T2DM in both genders. For resting heart rate categories of <60, 60-69, 70-79, and ≥80 beats/min, adjusted odds ratios for undiagnosed T2DM were 1.04, 2.32, 3.66 and 1.05, 1.57, 2.98 in male and female subjects, respectively. For male subjects, resting heart rate ≥70 beats/min could predict undiagnosed T2DM with 76.56% sensitivity and 48.64% specificity. For female subjects, the optimum cut-off point was ≥79 beats/min with 49.72% sensitivity and 67.53% specificity. The area under the ROC curve for predicting undiagnosed T2DM was 0.65 (95% CI: 0.64-0.66) and 0.61(95% CI: 0.60-0.62) in male and female subjects, respectively. CONCLUSIONS: Fast resting heart rate is associated with an increased risk of undiagnosed T2DM in male and female subjects. However, resting heart rate as a marker has limited potential for screening those at high risk of undiagnosed T2DM in adults living in rural areas.

Quantitative evaluation of acute renal failure in rabbits with contrast-enhanced ultrasound / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Assessment of perfusion in the early period of acute renal failure (ARF) is important, and can not be made by conventional ultrasound. The aim of this study was to prospectively test in a rabbit ARF model whether real-time contrast-enhanced ultrasound (CEUS) can quantitatively evaluate the hemodynamic changes of renal cortex in the early period.</p><p><b>METHODS</b>The model of ARF was induced in 30 healthy New Zealand white rabbits (2.5 - 3.0 kg), by intramuscular injection of 50% glycerin solution (12 ml/kg). CEUS were performed on right kidneys before, 6 and 24 hours after glycerin injection. CEUS quantitative indexes were measured in renal cortex using QLAB software. Comparisons between different stages were performed using paired t test. The sensitivity of CEUS in diagnosing ARF was compared with blood serum urea nitrogen (BUN), serum creatinine (SCr) level and color Doppler flow imaging (CDFI).</p><p><b>RESULTS</b>Among quantitative indexes, time to peak (TTP) and area under curve (AUC) increased significantly from (5.86 ± 2.57) seconds and (124.4 ± 46.7) dB·s before glycerin injection to (7.66 ± 2.05) seconds and (288.1 ± 64.9) dB·s 6 hours after injection (P < 0.05). Slope rate of ascending curve (A) and descending curve (a) decreased slightly from (3.00 ± 1.22) dB/s and (0.19 ± 0.15) 1/s to (2.80 ± 1.45) dB·s and (0.09 ± 0.02) 1/s (P < 0.05). Twenty-four hours later, only AUC increased significantly from (124.4 ± 46.7) dB·s to (466.2 ± 52.2) dB·s (P < 0.05).</p><p><b>CONCLUSION</b>Quantitative indexes of CEUS might be useful in predicting the hemodynamic changes of renal cortex in the early six hours of ARF model.</p>

Atypical class 1 integron coexists with class 1 and class 2 integrons in multi-drug resistant Shigella flexneri isolates from China.

The antimicrobial resistance and the character of integrons were determined in 58 Shigella flexneri strains isolated from China. All isolates were multi-drug resistant and found to carry integrons of class 1 (94.8%), class 2 (100%), or both (94.8%). No intI3 was detected. The typical class 1 integrons were found in conjugative plasmids and could be transferred to the recipient E. coli DH5α. The gene cassettes of typical class 1 integrons dfrA17-aadA5 and dfrA12-orfF-aadA2 were detected in 54 strains (93.1%) and 1 strain, respectively. Atypical class 1 integrons located on the chromosome with gene cassettes bla (oxa-30)-aadA1 were detected in 55 isolates (94.8%). All the intI2 positive isolates carried gene cassettes dfrA1-sat1-aadA1. To our knowledge, this is the first report that atypical and typical class 1 integrons coexisted with class 2 integron in multi-drug resistant S. flexneri strains.

Quantitative evaluation of contrast-enhanced ultrasound in the early diagnosis of acute renal failure of rabbits / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the early diagnostic value of contrast-enhanced ultrasound (CEUS) in acute renal failure (ARF) of rabbit.</p><p><b>METHODS</b>The rabbit model of ARF was established by intramuscular injection of 50% glycerin (12 ml/kg) into the hind legs of 18 New Zealand rabbits. CEUS was performed for both kidneys before injection and 6 hours after the injection. The slope rate of ascending curve (A), the slope rate of descending curve (alpha), area under curve (AUC), derived peak intensity (DPI), and time to peak (TTP) were measured in renal cortex of rabbits using Q-lab software package. Blood serum urea nitrogen (BUN) and serum creatinine (SCr) were measured.</p><p><b>RESULTS</b>The values of A and alpha before the injection of glycerin were (3.07 +/- 1.83) dB/s and (0.19 +/- 0.15)/s, respectively, which were significantly higher than the values after injection [ (2.76 +/- 1.31) dB/s and (0.09 +/- 0.02)/s, respectively] (P < 0.05). The values of AUC and TTP before the injection of glycerin were (137.4 +/- 68.4) dB s and (6.33 +/- 3.71) s, which were significantly lower than the values after injection [(309.5 +/- 88.9) dB s and (8.61 +/- 3.97) s, respectively] (P < 0.01). No significant change of DPI, BUN or SCr was found.</p><p><b>CONCLUSIONS</b>CEUS can precisely display the hemodynamic change of ARF model of rabbit in the early stage, with superior sensitivity than BUN and SCr. It may be a promising imaging method for the early diagnosis of ARF.</p>

[Construction, expression and purification of UreB-Omp11 fusion protein of Helicobacter pylori and its immunocompetence].

AIM: To construct H.pylori vaccine candidate strain expressing UreB-Omp11 recombinant fusion protein of H.pylori. To express and purify the fusion protein UreB-Omp11 and to determine its immunocompetence. METHODS: The two genes were amplified by PCR, and the fusion gene ureB-omp11 was amplified by over lap extension PCR and then cloned into the fusion expression vector pET30a(+), pET28a(+) and pMAL-c2X. The appropriate expression system was selected, and the recombinant UreB-Omp11 fusion protein was expressed and indentfied by SDS-PAGE and Western blot analysis. Then the fusion protein was purified by MBP affinity chromatography and the purity was indentfied by SDS-PAGE. Then the fusion protein was immunized to mice. The immunized mice sera were analyzed by Western blot with purified fusion protein. RESULTS: The ureB-omp11 fusion gene was correctly insected into pET30a(+) and confirmed by Enzyme digestion and sequencing analysis; Results in SDS-PAGE and optical density scanning demonstrated that this fusion protein MBP-UreB-Omp11 was expressed in the recombinant strain of E.coli TB1(pMAL-ureB-omp11). The fusion protein UreB-Omp11 was recognized by the mice sera immunized by H.pylori, the human sera infected with H.pylori and The purity of fusion protein was 90% after purification. The fusion protein purified could be recognized by corresponding antibody of mice sera immunized by this fusion piotein, This fusion protein has strong immunoantigenicity and immunoreactivity. CONCLUSION: The prokaryotic expression system TB1 (pMAL-c2X-ureB-omp11) was successfully constructed and selected. The results obtained lay the foundation for research on development of protein and DNA vaccine of Hp.

[Secular trend of nosocomial pneumonia in an university hospital in Zhengzhou].

OBJECTIVE: To investigate the secular trend of infection rate, risk factor exposure rates for nosocomial pneumonia (NP), and to evaluate the nosocomial infection surveillance and control programs efficacy in an university hospital from 1993 to 2000. METHODS: All 126 665 hospitalized patients from 1993 to 2000 were studied for NP. The independent risk factors for NP were analyzed by using case-control study method and logistic regression technique. The time-specific rates for NP and risk factor exposure were calculated annually. RESULTS: The infection rates for NP were decreased by 50% from 1.20% in 1993 to 0.60% in 2000. The logistic regression analysis showed that the independent risk factors for NP were immunosuppressive therapy (OR = 2.72), chemotherapy (OR = 2.17), cancer (OR = 1.45), chronic obstructive pulmonary disease (COPD, OR = 1.88), ICU (OR = 3.18), coma (OR = 3.26), tracheotomy (OR = 14.95), hemodialysis (OR = 5.12), bone or lumbar puncture (OR = 1.82). The time-trends for exposure rates of COPD and bone or lumbar puncture were slightly decreased, however those for the others and the synthetic risk factors were not changed significantly. CONCLUSION: The infection rates for NP were significantly decreased in the case of no change for exposure rates of risk factors for NP, this suggests that the nosocomial infection surveillance and control programs were effective for lowering infection rate for NP in this hospital.

Fusion expression of Helicobacter pylori neutrophil-activating protein in E.coli.

AIM: To produce a recombinant protein rMBP-NAP, which was fusionally expressed by Helicobacter pylori (H pylori) neutrophil-activating protein (NAP) and E. coli maltose-binding protein (MBP) and to evaluate its immunoreactivity and immunogenicity. METHODS: Neutrophil-activating protein gene of H pylori (HP-napA) was subcloned from the recombinant plasmid pNEB-napA, and fused to MalE gene of expressing vector pMAL-c2x. The recombinant plasmid pMAL-c2x-napA was confirmed by restriction enzyme digestion, and then transformed into E. coli TB1. Fusion protein rMBP-NAP was induced by IPTG and identified by SDS-PAGE analysis. Soluble rMBP-NAP was purified by amylose affinity chromatography. Immunoreactivity and immunogenicity of the fusion protein were evaluated by animal experiment, Western blotting with human H pylori anti-sera. RESULTS: E.coli TB1 carrying recombinant plasmid pMAL-c2x-napA was constructed and led to a high efficiency cytosol expression of fusion protein rBMP -NAP when induced by IPTG. The molecular weight of rBMP-NAP was about 57 kD, accounting for 37.55% of the total protein in the sonicated supernatant of E. coli TB1 (pMAL-c2x-napA). The purity of the fusion protein after one-step affinity chromatography was 94% and the yield was 100 mg per liter of bacterial culture. The purified fusion protein could be specifically recognized by both human anti-sera from clinical patients with H pylori infection and rabbit sera immunized by rMBP-NAP itself. CONCLUSION: Recombinant protein rMBP-NAP might be a novel antigen for vaccine development against H pylori.

[Study on the molecular mechanism of quinolone resistance in Shigellae spp].

OBJECTIVE: To study the resistance and its mechanism of Shigellae spp. to quinolones. METHODS: Seventy-three clinical isolates were collected. Susceptibility tests of pipemidic adcid (PI), ofloxacin (OFL), norfloxacin (NOR), and ciprofloxacin (CIP) were performed in all clinical isolates and Shigella 51573. The N-terminal coding region of gyrA and parC were amplified by polymerase chain reaction (PCR) respectively. Restriction fragment length polymorphism (RFLP) was applied to all PCR procucts of gyrA and parC, and single strand conformational polymorphism analysis (SSCP) was also applied to PCR procucts of parC. RESULTS: The resistance rates for all the Shigella spp. to PI, CIP, NOR and OFL were 79.5%, 60.3%, 41.1% and 36.9%. Sixty-seven strains (91.8%) were quinolone-reduced-sensitive isolates, in which 61 strains (91%) were found carrying mutations in gyrA with 5 strains (7.5%) found carrying mutations in parC. No mutation was found in 6 quinolone-sensitive isolates or Shigella 51573. CONCLUSION: The Shigella spp. had high resistance rates to quinolones. The target gene mutations which were mainly found in gyrA and secondarily in parC, played an important role in the quinolone-resistance in Shigella spp.