1.Methicillin-resistant Staphylococcus aureus colonization in infants at neonatal intensive care unit and effect of mupirocin decolonization
Yumao HUANG ; Weimin JIN ; Wenna XIANG
Chinese Journal of Perinatal Medicine 2017;20(5):382-386
Objective To evaluate the methicillin-resistant Staphylococcus aureus (MRSA) colonization in infants at neonatal intensive care unit (NICU) by active surveillance cultures (ASC) and the effects of mupirocin decolonization on MRSA infection. Methods Neonates adimitted to NICU of Ruian People's Hospital of Zhejiang Province, China between October 1, 2013 and September 30, 2014 underwent ASC within 24 hours of admission (ASC group). The samples from nasal vestibule and umbilicus were cultured for MRSA, and positive cultures were considered as MRSA colonization. These with negative cultures underwent repeated culture of MRSA by ASC at the 1st and 2nd week after NICU admission. Neonates admitted to NICU between October 1, 2014 and September 30, 2015 with MRSA colonization based on ASC were decolonized with mupirocin at both nasal vestibule and umbilicus twice daily for five consecutive days (decolonization group). Culture samples were obtained one day and one week after decolonization to repeat ASC. ASC was stopped if the subsequent culture was negative twice successively; and a second mupirocin decolonizaton was performed if the culture was positive. Chi-square test was used to compare the rates of colonization and infection between the two groups. Results (1) MRSA colonization and infection in ASC group: MRSA colonization rates within 24 hours, and in the 1st and 2nd week after NICU admission in ASC group were 2.2% (9/418), 3.7% (15/402) and 3.6% (13/361), respectively. Compared with those without MRSA colonization, neonates with MRSA colonization had a higher incidence of MRSA infection [13.5% (5/37) vs 3.7% (14/381), χ2=7.524, P=0.006]. (2) MRSA colonization and infection in decolonization group: MRSA colonization rates within 24 hours, and at the 1st and 2nd week after NICU admission in decolonization group were 2.8% (12/435), 2.9% (12/414) and 1.3% (5/373), respectively. The MRSA colonization rate at the 2nd week was significantly lower than that in ASC group (χ2=3.919, P=0.048). Twenty-nine cases had MRSA colonization, among which, 27 cases were decolonized once and two cases were decolonized twice, and all were successful. The rate of MRSA infection in decolonization group was 2.1% (9/435), which was significantly lower than in ASC group [4.5% (19/418)] (χ2=4.118, P=0.042). Conclusions Rate of MRSA colonization is high at NICU. Mupirocin can decolonize MRSA carriage and reduce MRSA infection in neonates.
2.Production of L(+)-tartaric acid by immobilized Rhizobium strain BK-20.
Xiang LAN ; Wenna BAO ; Haifeng PAN ; Zhipeng XIE ; Jianguo ZHANG
Chinese Journal of Biotechnology 2014;30(2):315-319
The cis-epoxysuccinate hydrolase (CESH) from Rhizobium strain BK-20 is the key enzyme for L(+)-tartaric acid production. To establish a highly efficient and stable production process, we first optimized the enzyme production from Rhizobium strain BK-20, and then developed an immobilized cell-culture process for sustained production of L(+)-tartaric acid. The enzyme activity of free cells reached (3 498.0 +/- 142.6) U/g, and increased by 643% after optimization. The enzyme activity of immobilized cells reached (2 817.2 +/- 226.7) U/g, under the optimal condition with sodium alginate as carrier, cell concentration at 10% (W/V) and gel concentration at 1.5% (W/V). The immobilized cells preserved high enzyme activity and normal structure after 10 repeated batches. The conversion rate of the substrate was more than 98%, indicating its excellent production stability.
Alginates
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chemistry
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Cells, Immobilized
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Glucuronic Acid
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chemistry
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Hexuronic Acids
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chemistry
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Hydrolases
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metabolism
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Rhizobium
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enzymology
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metabolism
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Tartrates
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metabolism
3.Comparison of the diagnosis value of neutrophil CD64 and CRP as a sin-gle test for the early detection of neonatal sepsis
Fang YANG ; Fangfang TU ; Wenna XIANG ; Qidan ZENG
China Modern Doctor 2014;(29):24-27
Objective To compare the diagnostic accuracy between neutrophil CD64 and C-reactive protein (CRP) as a single test for the early detection of neonatal sepsis. Methods A total of 36 patients who were hospitalized in neonatal intensive care unit (NICU) in our hospital were divided into documented sepsis group(n=10), clinical sepsis group (n=14) and control newborns (n=12). CRP, neutrophil CD64, complete blood counts and blood culture were detected at the time of the suspected sepsis for the documented or clinical group. CD64 was measured by automatic flow cytometry. The di-agnostic value of CRP and CD64 was assessed by receiver operating characteristic (ROC) curve analysis. Results CD64 was significantly elevated in the groups with documented or clinical sepsis, whereas CRP was not significantly increased compared with controls. For documented sepsis group, CD64 and CRP had a sensitivity of 92% and11%, a specificity of 83% and 80%, a positive predictive value of 83% and 34% and a negative predictive value of 91% and 50%, respectively, with a cutoff value of 3.2 mg/dL for CD64 and 1.1 mg/dL for CRP. Conclusion The diagnostic ac-curacy of CD64 is superior to CRP when measured at the time of suspected sepsis, which implies that CD64 is a more reliable marker for the early identification of neonatal sepsis as a single determination compared with CRP.