Acinetobacter pullorum sp. nov., Isolated from Chicken Meat

A bacterial strain, designated B301^T and isolated from raw chicken meat obtained from a local market in Korea, was characterized and identified using a polyphasic taxonomic approach. Cells were gram-negative, non-motile, obligate-aerobic coccobacilli that were catalase-positive and oxidase-negative. The optimum growth conditions were 30°C, pH 7.0, and 0% NaCl in tryptic soy broth. Colonies were round, convex, smooth, and cream-colored on tryptic soy agar. Strain B301^T has a genome size of 3,102,684 bp, with 2,840 protein-coding genes and 102 RNA genes. The 16S rRNA gene analysis revealed that strain B301^T belongs to the genus Acinetobacter and shares highest sequence similarity (97.12%) with A. celticus ANC 4603^T and A. sichuanensis WCHAc060041^T. The average nucleotide identity and digital DNA-DNA hybridization values for closely related species were below the cutoff values for species delineation (95-96% and 70%, respectively). The DNA G+C content of strain B301^T was 37.0%. The major respiratory quinone was Q-9, and the cellular fatty acids were primarily summed feature 3 (C_16:1 ω6c/C_16:1 ω7c), C_16:0, and C_18:1 ω9c. The major polar lipids were phosphatidylethanolamine, diphosphatidyl-glycerol, phosphatidylglycerol, and phosphatidyl-serine. The antimicrobial resistance profile of strain B301^T revealed the absence of antibiotic-resistance genes. Susceptibility to a wide range of antimicrobials, including imipenem, minocycline, ampicillin, and tetracycline, was also observed. The results of the phenotypic, chemotaxonomic, and phylogenetic analyses indicate that strain B301^T represents a novel species of the genus Acinetobacter, for which the name Acinetobacter pullorum sp. nov. is proposed. The type strain is B301^T (=KACC 21653^T = JCM 33942^T).

[Radiation dose and image quality of noncontrast chest CT in domestic and imported main stream manufacturers]

Objective: To compare the radiation dose and image quality of noncontrast chest CT and detection of ground-glass opacity pulmonary nodules (GGN) in domestic 128-slice spiral CT with the other CT scanners from three main stream manufacturers. Methods: From May 8, 2018 to October 31, 2018, noncontrast chest CT images from Neusoft 128-slice CT (75 males, 25 females, (42±16) years), dual-source 64-slice CT (53 males, 47 females, (50±16) years) and dual-source 128-slice CT scanners(69 males, 31 females, (62±17) years), Toshiba 128-slice CT (51 males, 49 females, (58±13) years) and GE 128-slice CT scanner (55 males, 45 females, (60±10) years) were collected in Eastern Theater Command and Tianjin People's Hospital. Radiation dose and image quality were evaluated.GGN detected both in Neusoft CT and dual-source CT scanners were used to analyze the displaying ability of lesions. Results: The noise in lung window of Neusoft CT ((37.8±4.9) HU) was higher than that of other mainstream CT scanners, and the noise in mediastinal window ((8.4±1.9) HU) was lower than that of GE 128-slice CT ((9.8±3.2) HU), but higher than that of dual-source CT and Toshiba 128-slice CT ((6.9±3.5)HU) (P<0.05). The absolute value of lung SNR in Neusoft CT was lower than that of other mainstream CT scanners, and the SNR in aorta (4.6±1.3) was lower than those of dual-source CT and Toshiba 128-slice CT(6.8±2.2) (P<0.05), but was not statistically significant compared with GE 128-slice CT (5.0±1.7). The mean CT value of upper lung ((-863±31) HU) at Neusoft CT was higher than 128-row dual-source CT ((-869±35) HU), and the mean CT value of aorta ((37±7) HU) was lower than that of Toshiba 128-slice CT((42±7) HU) and GE 128-slice CT ((45±9) HU) (P<0.05), while the mean CT values of the remaining lung and aorta were not statistically significant (P>0.05). The two readers had good to excellent consistency for image quality in five scanners (the highest kappa value=0.984). The delineation ability of Neusoft CT for GGN boundary was lower than that of dual-source CT (P<0.05), but had similar abilities to display the solid components, lobulation, burring, vacuoles, vascular bundle sign and pleural depression sign of GGN (all P>0.05). Radiation dose of Neusoft CT was lower than Toshiba 128-slice CT, but higher than dual-source 64-sliceCT and GE 128-slice CT scanners (P<0.05). Conclusions: With lower radiation dose than Toshiba 128-slice CT, Neusoft CT chest examination can meet the requirements of clinical diagnosis, but higher radiation dose and the lower image quality than dual-source CT and GE 128-slice CT shown in this study indicate further improvement is needed in terms of software and hardware.

[The clinical observation of serum specific biomarkers in patients with chronic graft-versus-host disease]

目的

研究异基因造血干细胞移植后患者血清生物标志物表达水平对慢性移植物抗宿主病（cGVHD）早期诊断的价值。

方法

采用液相悬浮芯片法检测接受异基因造血干细胞移植后发生和未发生cGVHD患者5种血清蛋白标志物（IL-1b、IL-16、CXCL9、CCL19、CCL17）表达水平。

结果

相较于未发生cGVHD的对照组，cGVHD患者血清中CXCL9、CCL17表达水平显著升高（P<0.05），其中CCL17与cGVHD的疾病严重程度相关（P<0.001）；CXCL9在皮肤损害的cGVHD患者血清中显著升高（P<0.01），CCL17在肝脏为靶器官的cGVHD患者中表达水平显著升高（P<0.01）。

结论

CXCL9联合CCL17可作为cGVHD的血清生物标志物，对辅助cGVHD诊断和评估严重程度有一定参考价值。

[Self-made finger flexion band and its application in patients with burn scar contracture on the back of hand]

Scar contracture after burn on the back of hand can easily lead to the limitation of flexion function of fingers, which seriously affects daily life activities. Generally, comprehensive rehabilitation treatment is adopted for scar contracture on the back of hand, among which wearing braces is an effective treatment method. However, some braces will limit the normal finger joints or must wait until all the affected fingers heal before they can be worn, and the wearing operation is quite complicated. In order to solve these problems, the author designed and made a finger flexion band, which was used to stretch the patients with limited flexion of finger caused by scar contracture after burn on the back of hand, and achieved good therapeutic effect. According to the measured hand size, the finger flexion band is cut and spliced from the fabric commonly used in daily life. The finger flexion band is designed with finger sleeve, which will not limit the normal finger joints, can interfere with the healed finger in advance, fix the corresponding fingers better, and improve the treatment comfort, especially for children who do not cooperate with the braces wearing. This finger flexion band is simple to make, cheap, convenient to use, and suitable for clinical promotion.

P1693The longitudinal associations between telomere attrition and the effects of blood pressure lowering and antihypertensive treatment

Background

Leukocyte telomere length, as an emerging marker of biological age, has been shown to associate with hypertension. However, it has not been studied whether telomere attrition rate in patients with hypertension is related to the heterogeneity of blood pressure (BP) response to antihypertensive therapy.

Purpose

Our aim is to investigate the relationship between telomere attrition rate and BP lowering in a longitudinal Chinese hypertensive cohort. We also aim to explore the potential association between telomere attrition rate and the differences in antihypertensive treatment response.

Methods

A community-based, prospective study was conducted at BenXi county, Liaoning province, in the northern China. A total of 3,671 hypertensive patients were recruited from 2013 t 2015 and of whom 1,382 provided blood samples at baseline. After a median follow-up period of 2.2 (range 1.5–2.4) years, the blood samples were collected from 1,197 patients again in 2016, and 185 patients were not reached to obtain blood sample because of immigration. In addition, 89 blood samples were excluded due to insufficient quality. Finally, 1,108 patients who are available for blood samples both at baseline and at follow-up, were included in the analysis for telomeres change. Annual telomere attrition rate was calculated as (follow-up telomere length-baseline telomere length)/follow-up year, and then categorized into two groups: the shorten (annual telomere attrition rate <0) and the lengthen (annual telomere attrition rate >0). Multivariable linear regression model was used to examine the association of annual telomere attrition rate with blood pressure lowering and antihypertensive treatment. Cox Proportional Hazards model was used to examine the association between annual telomere attrition rate and cardiovascular disease risk.

Results

In multivariable linear regression models, the telomere lengthening was significantly associated with decrease in systolic blood pressure (SBP) (β: −4.13; p=0.006) and pulse pressure (PP) (β: −3.22; p=0.007) during the follow-up, but not associated with diastolic blood pressure (DBP) change. And the associations were observed age- and gender-specific difference. The lengthen was significantly associated with ΔSBP and ΔPP in women and younger patients (age ≤60 years old). Furthermore, the associations were observed in patients who treated with calcium channel blocker (CCB) and angiotensin receptor blocker (ARB), but not in diuretics. Then we found no significant association between annual telomere attrition rate and incident cardiovascular events during the follow-up.

Conclusion(s)

Our data showed that the increasing of leukocyte telomere length is associated with the decreasing of SBP and PP, particularly for the patients who received CCB and ARB therapy. These data showed that annual telomere attrition rate could be a marker of treatment response and will help in clinical management.

Acknowledgement/Funding

the National Science and Technology Pillar Program during the Twelfth Five-year Plan Period (No. 2011BAI11B04)

Safety, efficacy and tumor mutational burden as a biomarker of overall survival benefit in chemo-refractory gastric cancer treated with toripalimab, a PD-1 antibody in phase Ib/II clinical trial NCT02915432

BACKGROUND

High tumor mutational burden (TMB-H) is correlated with enhanced objective response rate (ORR) and progression-free survival (PFS) for certain cancers receiving immunotherapy. This study aimed to investigate the safety and efficacy of toripalimab, a humanized programmed death-1 (PD-1) antibody, in advanced gastric cancer (AGC), and the predictive survival benefit of TMB and PD-L1.

PATIENTS AND METHODS

We reported on the AGC cohort of phase Ib/II trial evaluating the safety and activity of toripalimab in patients with AGC, oesophageal squamous cell carcinoma, nasopharyngeal carcinoma and head and neck squamous cell carcinoma. In cohort 1, 58 chemo-refractory AGC patients received toripalimab (3 mg/kg d1, Q2W) as a monotherapy. In cohort 2, 18 chemotherapy-naive AGC patients received toripalimab (360 mg d1, Q3W) with oxaliplatin 130 mg/m2 qd, d1, capecitabine 1000 mg/m2 b.i.d., d1-d14, Q3W as first-line treatment. Primary end point was ORR. Biomarkers such as PD-L1 and TMB were evaluated for correlation with clinical efficacy.

RESULTS

In cohort 1, the ORR was 12.1% and the disease control rate (DCR) was 39.7%. Median PFS was 1.9 months and median OS was 4.8 months. The TMB-H group showed significant superior OS than the TMB-L group [14.6 versus 4.0 months, HR = 0.48 (96% CI 0.24-0.96), P = 0.038], while PD-L1 overexpression did not correlate with significant survival benefit. A 77.6% of patients experienced at least one treatment-related adverse event (TRAE), and 22.4% of patients experienced a grade 3 or higher TRAE. In cohort 2, the ORR was 66.7% and the DCR was 88.9%. A 94.4% of patients experienced at least one TRAE and 38.9% of patients experienced grade 3 or higher TRAEs.

CONCLUSIONS

Toripalimab has demonstrated a manageable safety profile and promising antitumor activity in AGC patients, especially in combination with XELOX. High TMB may be a predictive marker for OS of AGC patients receiving toripalimab as a single agent.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02915432.

Detection of antibodies against hepatitis E virus in pet veterinarians and pet dogs in South Korea

Hepatitis E virus (HEV) is a zoonotic pathogen commonly considered an important foodborne virus. Pet dogs are important reservoirs of zoonotic agents. In the present study, the seroprevalence of HEV in pet dogs and pet veterinarians were found to be 28.2 and 5.0%, respectively. It remains unclear whether pet veterinarians are at higher risk of HEV transmission. However, pet animals and individuals who have contact with infected animals must be continually monitored for public health concerns.

[Data analysis on HIV/AIDS sentinel surveillance programs targeting community population in Liangshan Yi Autonomous Prefecture, 2010-2015]

Objective: To investigate the epidemiologic and behavioral characteristics of HIV among community population in Liangshan prefecture. Methods: We collected social demographic, behavioral and serological information by means of the monitoring questionnaire and serological tests. Data was analyzed by using the chi-square test and logistic regression. Results: From April to June of 2010 to 2015, 14 092 cases of community population were selected as the study objects, with 267 cases diagnosed as HIV positive patients. The HIV positive rates were 3.24%, 3.07%, 1.17%, 1.38%,1.42% and 1.25%, respectively. We observed that when community population having the following characteristics as: living in Butuo country (OR=3.83), being males (OR=1.77), being Yi nationality (OR=4.40) being widowed (OR=28.57), with history of drug abuse (OR=3.71) or injecting drug use (PWID) (OR=4.92), or history of needle sharing among PWID (OR=8.53), were under higher risks for HIV infection. With histories as: having had secondary or above levels of schooling (OR=0.59), having protected sex with regular partners (OR=0.21) and with non-regular partners (OR=0.46), they seemed to be somehow protected for getting HIV infection. Conclusion: The positive HIV rates of HIV among community population in Dechang, Ningnan and Butuo varied from 0.10% to 8.77% while the HIV transmission among general population remained challenging.

Carriage of Staphylococcus schleiferi from canine otitis externa: antimicrobial resistance profiles and virulence factors associated with skin infection

The recent emergence of Staphylococcus schleiferi in dogs with otitis externa or skin and soft tissue infections has become a significant zoonotic issues. In the current study, we investigated 1) the carriage rates of S. schleiferi among major staphylococci in healthy dogs and dogs with otitis externa, 2) antibiotic susceptibility profiles of S. schleiferi, particularly methicillin resistance (MR), and 3) virulence factors associated with skin and soft tissue infections such as ability to form biofilm, resistance to cationic antimicrobial peptides (CAMPs), and carriage of staphylococcal enterotoxin genes. Among the 21 S. schleiferi isolates, 5 isolates (24%) were determined to be methicillin-resistant (MRSS). Staphylococcal cassette chromosome mec (SCCmec) typing revealed the presence of SCCmec type V in 4 MRSS isolates and type VII in one MRSS. Higher levels of antibiotic resistance, especially multidrug resistance, were observed in MRSS isolates compared to the methicillin-susceptible S. schleiferi (MSSS) isolates. In addition, MRSS isolates exhibited enhanced ability to form biofilm under static condition and all the 5 MRSS isolates carried three or more enterotoxin genes. However, there were no significant differences in resistance to CAMPs between MRSS and MSSS isolates. These findings suggest that coagulase-negative S. schleiferi is becoming more prevalent in canine otitis externa cases. Our results also highlight the presence of multidrug-resistant MRSS isolates with enhanced biofilm production and carriage of multiple enterotoxins.

Potential role of host defense antimicrobial peptide resistance in increased virulence of health care-associated MRSA strains of sequence type (ST) 5 versus livestock-associated and community-associated MRSA strains of ST72

The most significant community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in Korea is sequence type (ST) 72 with staphylococcal cassette chromosome mec (SCCmec) type IV (ST72-MRSA-IV). Although the impact of CA-MRSA on the clinical outcomes versus healthcare-associated (HA)-MRSA remains unclear, it has recently been revealed that ST5 HA-MRSA-II is associated with higher mortality compared with ST72 CA-MRSA-IV, suggesting higher virulence in ST5 HA-MRSA-II strains. In this investigation, human-/animal-originated ST72-MRSA-IV strains were examined for virulence phenotypes and compared with those of ST5-MRSA-II strains, the established HA-MRSA in Korea. Overall, ST5 HA-MRSA-II strains demonstrated higher levels of resistance to host defense-cationic antimicrobial peptides of human (LL-37), bovine (BMAP-28), and bacterial (polymyxin B) origins versus ST72-MRSA-IV strains via enhanced surface positive charge. Hemolysis profiles, gelatinase activity, and staphylococcal superantigen gene profiles were not different between ST72 CA-MRSA and ST5 HA-MRSA strains. However, ST5 HA-MRSA strains were able to downregulate initial cytokine response in murine macrophages.

[Application of self-made stretch pants in patients with burn in special sites]

The change and fixation of dressing are difficult in patients with burn in special sites of perineum, buttocks, and bilateral thighs. Therefore, we designed and made stretch pants by ourselves for dressing fixation after dressing change in patients with burns in abdomen, buttocks, and bilateral thighs. The stretch pants are made by cutting and splicing elastic fabric according to perimeters of abdomen and legs. The stretch pants are used after wound dressing change, which can fix the dressing stably, accelerate wound healing, and reduce the medical workers' labor intensity of dressing change and economic burden of patients. And patients can walk out of bed early. It's especially suitable for dressing fixation of infants and other patients who are unwilling to cooperate. Besides, it's easy to make with low cost and suitable for clinical promotion.

Adaptations of Vancomycin-Intermediate Sequence Type 72 Methicillin-Resistant Staphylococcus aureus for Daptomycin Nonsusceptibility

In Korea, the major clonal type of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is sequence type 72 (ST72) with staphylococcal cassette chromosome mec (SCCmec) type IV (ST72-MRSA-IV). In this study, we used a previously well-characterized isogenic pair of ST72 vancomycin (VAN) susceptible-and VAN intermediate-MRSA strains (VSSA303 and VISA072) and several VSSA strains complemented with plasmids expressing single-point mutated genes (dprAG196C, femAF92C, vraRE127K, and vraSRE127K) identified in the VISA strain. Using the strain set, we assessed the (1) susceptibilities to daptomycin (DAP) and cationic antimicrobial peptides (CAMPs), (2) alterations in cell envelope phenotypes, such as cell wall autolysis, surface positive charge, and membrane potential (ΔΨ), (3) transcriptional expression profiles of genes involved in surface charge regulation and changes of ΔΨ, and (4) cytokine stimulation profiles in murine macrophages. The vraRE127K mutation could enhance surface positive charge through mprF- and dltABCD-independent mechanisms with thickened cell wall. However, none of the single-point mutated genes increased DAP resistance. The DAP nonsusceptible (DAP-NS) phenotype observed in VISA072 strain likely resulted from the combined effects of low ΔΨ and increased positive surface charge. These results suggest that physicochemical alterations in cell envelope are involved in the survival response of DAP-NS VISA072 in sites of infections.

Genetic alterations responsible for reduced susceptibility to vancomycin in community-associated MRSA strains of ST72

Objectives

We previously reported the first case of vancomycin treatment failure due to development of vancomycin-intermediate resistance in a patient with an MRSA of ST72, a community genotype in Korea. We investigated two isogenic MRSA strains from this patient, who experienced treatment failure with vancomycin and rifampicin.

Methods

We tracked the genetic alterations that confer reduced susceptibility to vancomycin on those two isogenic MRSA strains by WGS.

Results

Five non-synonymous mutations were identified, including rpoB (H481Y), dprA (G196C), femA (F92C), vraR (E127K) and agrC (E391stop). We further studied the role of a mutation of vraR in reduced susceptibility to vancomycin. Introduction of the mutated vraR (E127K) into a vancomycin-susceptible Staphylococcus aureus strain resulted in an increase in vraSR mRNA expression and vancomycin MIC and development of the hetero-VISA phenotype, which was confirmed by the population analysis profile (PAP)/AUC. Electron microscopy showed increased cell wall thickness in the strains with mutated vraR.

Conclusions

Based on the genomic data, molecular experiments and PAP and cell wall analyses, we propose that a single mutation of vraR is associated with the reduced susceptibility to vancomycin in MRSA and further treatment failure.

[Research on the effect of biological glue on augmenting the viscosity of tissue engineering retinal nerve scaffolds]

Objective: To evaluate the adhesion effect of tissue engineering retinal nerve scaffolds modified with biological glue. Methods: Experimental study. To fabricate a biological glue by blending laminin, collagen Ⅳ, entactin and HSPG(2) with phosphate-buffered saline (PBS) buffer solution, scaffolds were then modified with the biological glue of various concentration levels (10 μl/cm(2), 20 μl/cm(2), 30 μl/cm(2) and 40 μl/cm(2)). The effects of various concentration levels glue on inducing scaffold adhesion were analyzed after 24 h. Cell count method and CCK-8 kit were used to assess the effects of biological glue on cell growth and toxicity. Then the scaffolds modified with or without glue were transplanted into rabbit's retina by 23 G pars plana vitrectomy. Intraocular pressure(IOP) and retina examination were assessed by ICare, fundus photograph and OCT. The adhesion effects of various concentration levels glue were analyzed by chi-square test. The cell adhesion rate of different scaffolds was analyzed by Mann-Whitney U test. One-Way ANOVA was used to compare the cell survival rate of different scaffolds. After transplantation, the IOP variance of rabbits was analyzed by repetitive measurement deviation analysis. Results: Compared with the control groups, the maximum adhesion rate of the biological glue was 91.7% (χ(2)=8.79, P<0.05) at 30μl/cm(2) concentration level. After 24h of cultivation, cell adhesion rate of glue-scaffold group (86.85%) was significantly higher than that of pure scaffold group (13.78%, U=0.01, P<0.05), while there was no significant difference between the cell survival rates of the two groups (F=7.235, P=0.11). There was no significant difference (F=79.16, P=0.07) between the IOP of viscosity modified group [(18.4+0.93) mmHg (1 mmHg=0.133 kPa)] and non- modified group [(17.1±0.04)mmHg]. The retina adhesion rate of viscosity modified scaffold was 80% at 7 days postoperatively, and the fundus examination showed no inflammatory response in retina and vitreous cavity. Conclusion: This study showed that the biological glue has favorable viscosity modifying effect on tissue engineering neural retina scaffolds, which is beneficial for the biological material transplantation. (Chin J Ophthalmol, 2018, 54: 277-282).

TLR2 contributes to trigger immune response of pleural mesothelial cells against Mycobacterium bovis BCG and M. tuberculosis infection

Mycobacterium tuberculosis is a causative agent leading to pleural effusion, characterized by the accumulation of fluid and immune cells in the pleural cavity. Although this phenomenon has been described before, detailed processes or mechanisms associated with the pleural effusion are still not well understood. Pleural mesothelial cells (PMCs) are specialized epithelial cells that cover the body wall and internal organs in pleural cavity playing a central role in pleural inflammation. Toll-like receptors are expressed in various cell types including mesothelial cells and initiate the recognition and defense against mycobacterial infection. In the present study, we investigated direct immune responses of PMCs against two mycobacterial strains, M. bovis vaccine strain Bacille Calmette-Guérin (BCG) and M. tuberculosis virulent strain H37Rv, and the role of TLR2 in such responses. Infection with BCG and H37Rv increased the production of IL-6, CXCL1, and CCL2 in WT PMCs, which was partially impaired in TLR2-deficient cells. In addition, the activation of NF-κB and MAPKs induced by BCG and H37Rv was suppressed in TLR2-deficient PMCs, as compared with the WT cells. TLR2 deficiency led to the decrease of nitric oxide (NO) production through the delayed gene expression of iNOS in PMCs. TLR2 was also shown to be essential for optimal expression of cellular adhesion molecules such as ICAM-1 and VCAM-1 in PMCs in response to BCG and H37Rv. These findings strongly suggest that TLR2 participates in mycobacteria-induced innate immune responses in PMCs and may play a role in pathogenesis of tuberculosis pleural effusion.

Safety and efficacy of sofosbuvir-based treatment of acute hepatitis C in end-stage renal disease patients undergoing haemodialysis

BACKGROUND

Hepatitis C virus (HCV) infection in patients undergoing haemodialysis is prevalent and aggressive. The treatment of chronic hepatitis C has been revolutionised by the advent of direct-acting antivirals (DAAs). However, the safety, efficacy, and tolerance of DAAs in the treatment of acute HCV infection in patients with end-stage renal disease who are on haemodialysis are unknown.

AIM

To evaluate the safety and efficacy of sofosbuvir plus daclatasvir in this specific, difficult-to-treat population.

METHODS

We conducted a prospective and observational study of end-stage renal disease patients who were undergoing haemodialysis and were acutely infected with HCV. Patients received a half dose of sofosbuvir (200 mg) and a full dose of daclatasvir (60 mg) daily. The primary endpoint was the proportion of patients with sustained virological responses (SVRs); the other primary outcomes were safety and tolerability.

RESULTS

Thirty-three patients were enrolled in the study. The median HCV RNA viral load at baseline was 6.8 log₁₀ IU/mL. Twenty-four patients were infected with HCV genotype 2a, seven patients with 1b, and two patients with 2a+1b. All patients achieved a SVR at 12 weeks after the end of treatment. The treatment was well tolerated, and there were no drug-related serious adverse events.

CONCLUSION

A half dose of sofosbuvir (200 mg once daily) plus a full dose of daclatasvir (60 mg once daily) were suitable for the treatment of acute HCV-infected patients who were undergoing end-stage renal disease and were on haemodialysis.

Impact of Multiple Single-Nucleotide Polymorphisms Within mprF on Daptomycin Resistance in Staphylococcus aureus

A number of single nucleotide polymorphisms (SNPs) within the mprF open reading frame (ORF) have been associated with daptomycin-resistance (DAP-R) in Staphylococcus aureus. Such SNPs have been found throughout the mprF ORF, although there are clearly preferred "hot spots" within this gene frequently linked to DAP-R phenotype. These mprF SNPs are often correlated with a gain-in-function phenotype, either in terms of increased production (synthase activity) and/or enhanced translocation (translocase activity) of lysyl-phosphatidylglycerol (L-PG) within its cell membrane. However, it is unclear if multiple hot spot mprF SNPs can accumulate within mprF ORFs and cause additive elevations of DAP minimum inhibitory concentrations (MICs). In this study, we used a previously well-characterized plasmid complementation system in S. aureus Newman ΔmprF mutant to express: (1) single point-mutated forms of mprF ORFs cloned from two DAP-R S. aureus strains (mprF_S295L or mprF_T345A) and (2) dual point-mutated forms of mprF ORFs simultaneously harboring SNPs in the central bifunctional domain and synthase domain in MprF, respectively (mprF_S295L+L826F or mprF_T345A+L826F). The current study revealed that, although individual hot spot point mutations within mprF ORF can recapitulate signature DAP-R-associated phenotypes (i.e., increased DAP MICs, enhanced surface positive charge, and increased L-PG synthesis), accumulation of such hot spot point mutations paradoxically caused reduction in these latter three metrics.

Correlation between Physical Features of Elementary School Children and Chest Compression Depth

Introduction

The height and body weight of 6th grade elementary school children may have influence on chest compression.

Materials & methods

In accordance with the 2005 American Heart Association guidelines and 2006 Korean Association of CardioPulmonary Resuscitation (CPR) guidelines, a 25-minute audiovisual presentation and practical demonstration of CPR were presented by the researchers and assistants. The assistants supervised and corrected the practical performance of the students who performed 5 cycles of CPR (2 minutes each) with the aid of the Laerdal Resusci® Anne SkillReporter™. The students then carried out another 5 cycles of CPR (2 minutes each) using the skill reporter; and a short report was printed.

Results

The correlation coefficient between body weight and chest compression was 0.467 (p=0.000), and the correlation coefficient between height and chest compression was 0.309 (p=0.009). The intercept between body weight and chest compression was 21.763 (p=0.000), and the slope was 0.324 (p=0.000). Student height showed no linear correlation with chest compression depth.

Conclusions

The body weight of 6th grade elementary school children showed moderate correlation with chest compression depth. A minimal body weight of 50 kg is required to attain a standard chest compression depth of 38 mm. With improved training, some students with body weight less than 50 kg may also achieve satisfactory performance of CPR.

Nucleotide-Binding Oligomerization Domain 2 Contributes to Limiting Growth of Mycobacterium abscessus in the Lung of Mice by Regulating Cytokines and Nitric Oxide Production

Mycobacterium abscessus is a prominent cause of pulmonary infection in immunosuppressed patients and those with cystic fibrosis. Nucleotide-binding oligomerization domain (NOD) 2 is a cytosolic receptor which senses a bacterial peptidoglycan component, muramyl dipeptide (MDP). Although nucleotide-binding oligomerization domain 2 (NOD2) contributes to protect host against various microbial infections, it is still unclear whether NOD2 is essential to regulate host immune responses against M. abscessus infection. In this study, we sought to clarify the role of NOD2 and the underlying mechanism in host defense against M. abscessus infection. Mice were infected intranasally with M. abscessus and sacrificed at indicated time points. Bacterial survival, cytokines production, and pathology in the lungs were determined. Bone marrow-derived macrophages were used to clarify cellular mechanism of NOD2-mediated immune response. Bacterial clearance was impaired, and pathology was more severe in the lungs of NOD2-deficient mice compared with the wild-type mice. In macrophages, NOD2-mediated activation of p38 and JNK were required for production of proinflammatory cytokines and nitric oxide (NO) and expression of iNOS in response to M. abscessus. NO was critical for limiting intracellular growth of the pathogen. Intranasal administration of MDP reduced in vivo bacterial replication and thus improved lung pathology in M. abscessus-infected mice. This study offers important new insights into the potential roles of the NOD2 in initiating and potentiating innate immune response against M. abscessus pulmonary infection.

Emergence of Daptomycin-Nonsusceptible Methicillin-Resistant Staphylococcus aureus Clinical Isolates Among Daptomycin-Naive Patients in Korea

This study was conducted to assess emergence of daptomycin-nonsusceptible (DAP-NS) phenotype in DAP-naive patients with invasive Staphylococcus aureus (ISA) infections in Korea. A total of 208 S. aureus clinical isolates were selected from a previous prospective study on ISA infections and evaluated for DAP-NS. Although DAP has never been introduced in Korea, five DAP-NS S. aureus strains (2.4%) were identified among 208 S. aureus strains collected from ISA infections. The DAP-NS phenotype was observed only in methicillin-resistant S. aureus (MRSA) strains, but not in methicillin-susceptible S. aureus strains. One DAP-NS MRSA strain belonged to sequence type 72 (ST72) and four were ST5 MRSA strains, three of which were heteroresistant vancomycin (VAN)-intermediate S. aureus. All these five DAP-NS MRSA strains were from healthcare-associated infections without prior exposure to VAN within 30 days. While the ST72 MRSA strain exhibited DAP-NS phenotype via charge repulsion mechanism, four ST5 DAP-NS S. aureus strains had charge-independent DAP-NS mechanism. None of the five DAP-NS strains displayed significant increase in cell wall thickness, indicating that altered cell wall thickness was not associated with the observed DAP-NS phenotype.