The Role of NGAL in Peritoneal Dialysis Effluent in Early Diagnosis of Peritonitis: Case-Control Study in Peritoneal Dialysis Patients

♦ Background:

Peritoneal dialysis (PD) is frequently complicated by high rates of peritonitis, which result in hospitalization, technique failure, transfer to hemodialysis, and increased mortality. Early diagnosis, and identification of contributing factors are essential components to increasing effectiveness of care. In previous reports, neutrophil gelatinase-associated lipocalin (NGAL), a lipocalin which is a key player in innate immunity and rapidly detectable in peritoneal dialysis effluent (PDE), has been demonstrated to be a useful tool in the early diagnosis of peritonitis. This study investigates predictive value of PDE NGAL concentration as a prognostic indicator for PD-related peritonitis.

♦ Methods:

A case-control study with 182 PD patients was conducted. Plasma and PDE were analyzed for the following biomarkers: C-reactive protein (CRP), blood procalcitonin (PCT), leucocytes and NGAL in PDE. The cases consisted of patients with suspected peritonitis, while controls were the patients who came to our ambulatory clinic for routine visits without any sign of peritonitis. The episodes of peritonitis were defined in agreement with International Society for Peritoneal Dialysis guidelines. Continuous variables were presented as the median values and interquartile range (IQR). Mann-Whitney U test was used to compare continuous variables. Univariate and multivariate logistic regression were used to evaluate the association of biomarkers with peritonitis. Receiver operating characteristic (ROC) curve analysis was used to calculate area under curve (AUC) for biomarkers. Finally we evaluated sensitivity, and specificity for each biomarker. All statistical analyses were performed with SPSS version 17.0 (SPSS Inc., Chicago, IL, USA).

♦ Results:

During the 19-month study, of the 182 patients, 80 had a clinical diagnosis of peritonitis. C-reactive protein levels (p < 0.001), PCT (p < 0.001), NGAL in PDE (p < 0.001), and white blood cells (WBC) in PDE (p < 0.001) were all significantly different in patients with and without peritonitis. In univariate analysis, CRP (odds ratio [OR] 1,339; p = 0.001), PCT (OR 2,473; p < 0,001), WBC in PDE (OR 3,986; p < 0,001), and NGAL in PDE (OR 36.75 p < 0.001) were significantly associated with episodes of peritonitis. In multivariate regression analysis, only WBC (OR 24.84; p = 0,012), and peritoneal NGAL levels (OR 136.6; p = 0,01) were independent predictors of peritonitis events. Moreover, AUC for NGAL in peritoneal effluent was 0,936 (p < 0.001) while AUC for CRP, PCT, and WBC count in peritoneal effluent were 0,704 (p = 0.001), 0.762 (p = 0.039), 0,975 (p < 0.001), respectively. Finally, combined WBC and peritoneal NGAL test increased the specificity (= 96%) of the single test.

♦ Conclusions:

These results identify NGAL in peritoneal effluent as a reliable marker of peritonitis episodes in PD patients. Collectively, our findings demonstrate that the use of peritoneal NGAL cooperatively with current clinical diagnostic tools as a prognostic indicator, presents a valuable diagnostic tool in PD-associated peritonitis.     

急性戊型肝炎患者血清病毒抗原检测的临床意义

目的：探讨戊型肝炎抗原诊断试剂在临床诊断戊型肝炎病毒感染中的作用。方法：应用酶联免疫吸附试验方法检测戊型肝炎病毒抗原（HEV-Ag）试剂,对387例急性戊型肝炎患者血清标本进行检测,同时进行HEV RNA、抗HEV-IgM、抗HEV-IgG检测。结果：387例急性戊型肝炎患者血清HEV-Ag 140例（36.18%）阳性;单纯抗HEV-IgM阳性组的HEV-Ag阳性率最高;12例患者早期血清HEV-Ag阳性,随访过程中抗HEV-IgM与抗HEV-IgG阳转。结论：通过HEV-Ag检测,可以提高戊型肝炎病毒感染的诊断水平。     

反向斑点杂交快速检测肺炎链球菌

目的:建立一种利用DNA探针快速检测肺炎链球菌的反向斑点杂交方法.方法:在肺炎链球菌特异的自溶素基因序列内设计引物,聚合酶链反应合成1段263 bp的DNA探针,然后用生物素标记的细菌DNA与该探针行反向斑点杂交,并将该方法应用于痰样本的检测.结果:所合成的探针具有高度特异性,与其他细菌间无交叉反应,该方法能检测出10 ng细菌DNA.50份痰标本肺炎链球菌培养阳性者8份,杂交阳性者12份,PCR阳性者18份.结论:反向斑点杂交具有快速、敏感、特异的优点,对肺炎链球菌的快速诊断有重要意义.     

Detection of macrolide resistance in Streptococcus pneumoniae

We determined the susceptibilities of recent clinical isolates of Streptococcus pneumoniae to 19 antibiotics. The frequency of erythromycin nonsusceptibility was high, i.e. 8/13 (61.5%), 10/14 (71.4%) and 11/11 isolates (100%) from 13 penicillin-susceptible, 14 penicillin-intermediate and 11 penicillin-resistant S. pneumoniae, respectively. Macrolide resistance was detected by polymerase chain reaction (PCR) and disk diffusion methods. Of these erythromycin-nonsusceptible pneumococcal isolates, 13/29 (44.8%) isolates contained genomic copies of MEFA and showed non-'D'-shaped zones of inhibition observed around rokitamycin and/or clindamycin disks. Sixteen out of 29 isolates (55.2%) contained copies of ERMB and showed typical 'D'-shaped zones of inhibition, except one isolate. Although the macrolide resistance determinants, MEFA and ERMB, could be identified by PCR and disk diffusion methods, PCR methods were more reliable in elucidating these determinants. The susceptibility pattern to 14-, 15- and 16-membered macrolides and clindamycin differed between the MEFA+ and ERMB+ isolates. All isolates were susceptible to levofloxacin, sparfloxacin and vancomycin. The MICs of sitafloxacin were lowest among the fluoroquinolones examined for 38 isolates.     

Neutrophil Gelatinase-Associated Lipocalin in Peritoneal Effluent: Evaluation in Peritoneal Dialysis Patients in Basal Condition

♦ Purpose: In the present study, we assessed expression of neutrophil gelatinase-associated lipocalin (NGAL) in peritoneal effluent (pNGAL) from peritoneal dialysis (PD) patients, and we evaluated factors that might affect its level in basal conditions.♦ Methods: Our cross-sectional study included all 69 patients on PD at our institution. We evaluated patient history, hydration status, residual renal function, indices of dialysis adequacy, peritoneal transport type, serum C-reactive protein, ferritin, serum NGAL (sNGAL) and pNGAL. Univariate and multivariate linear regression models were used to evaluate predictors of pNGAL.♦ Results: Of the study patients, 39 (56.5%) were men, and 54 (78.3%) were on continuous ambulatory PD. Median age in the group was 61 years [interquartile range (IQR): 46.5 - 71 years]. Median sNGAL was 487 ng/mL (IQR: 407 - 586 ng/mL), and median pNGAL was 35 ng/mL (IQR: 21 - 46 ng/mL). dNGAL correlated directly with weekly dialytic clearance of creatinine (ρ = 0.291, p = 0.02) and with sNGAL (ρ = 0.269, p = 0.031). The same variables were also independent predictors of pNGAL (β = 0.30 and 0.29 respectively, both p < 0.05) in multivariate analysis.♦ Conclusions: In our analysis, basal levels of pNGAL were influenced by sNGAL and by dialytic clearance of creatinine.Key words: NGAL, biomarkers, peritoneal effluentNeutrophil gelatinase-associated lipocalin (NGAL) is a granulocyte-secreted polypeptide that specifically blocks bacterial growth by interfering with bacterial siderophores (1). Its role as marker has been evaluated in several conditions, including acute and chronic kidney disease (CKD), infections, and cancers. Moreover, some studies showed that NGAL secretion can be induced in epithelial cells during inflammatory insult. Specifically, Leung and colleagues (2) demonstrated secretion of NGAL by peritoneal mesothelial cells in a small group of peritoneal dialysis (PD) patients and suggested the usefulness of NGAL in PD effluent (pNGAL) for the diagnosis of peritonitis.Conversely, serum NGAL (sNGAL) is known to be high in patients with CKD (3), and high sNGAL might be paralleled by high pNGAL in PD patients. Moreover, certain systemic conditions such as hydration status or systemic inflammation may affect sNGAL (4) and consequently pNGAL. To date, no study assessing the possible interference of PD modality and systemic conditions on pNGAL concentration has been reported.The aim of the present study was to evaluate the consistency of pNGAL in basal conditions for describing a peritoneal local process and to evaluate how PD and systemic conditions might affect pNGAL values.     

Clinical Factors Associated with Negative Urinary Antigen Tests Implemented for the Diagnosis of Community-Acquired Pneumococcal Pneumonia in Adult Patients

Objective

This study investigated clinical factors associated with negative urinary antigen tests (UAT) implemented for the diagnosis of pneumococcal community-acquired pneumonia (CAP) in adult patients.

Subjects and Methods

We reviewed the medical records of 755 adult patients who completed the UAT in our hospital between 2009 and 2012. Of these, we evaluated 63 patients with bacteriologically confirmed definite pneumococcal CAP (33 were UAT-positive, and 30 were UAT-negative).

Results

There was no significant difference between the UAT-positive and the UAT-negative patients regarding age, dehydration, respiratory failure, orientation, blood pressure (ADROP) score (the CAP severity score proposed by the Japanese Respiratory Society), gender, white blood cell counts, liver/kidney function tests, or urinalysis. However, serum C-reactive protein (CRP) concentrations were 31s% lower in the UAT-negative patients than in the UAT-positive patients (p = 0.02). Furthermore, the prothrombin time-international normalized ratio was 50s% higher in the UAT-negative patients than in the UAT-positive patients, although the difference did not reach statistical significance (p = 0.06). The prevalence of comorbidities was similar in both UAT-positive and UAT-negative patients. However, warfarin had been prescribed in 8 (27s%) of the UAT-negative patients compared to only 1 (3s%) of the UAT-positive patients (odds ratio = 11.6; p = 0.01).

Conclusions

These results suggested that low serum CRP concentrations and the use of warfarin increased the possibility with which false-negative UAT results occurred in these patients with pneumococcal CAP.Key Words: Urinary antigen test, Community-acquired pneumonia, Streptococcus pneumoniae, Anticoagulation therapy     

Pneumococcal LytA autolysin, a potent therapeutic agent in experimental peritonitis-sepsis caused by highly beta-lactam-resistant Streptococcus pneumoniae

The in vitro and in vivo antipneumococcal activities of the main pneumococcal autolysin (LytA) and Cpl-1, a lysozyme encoded by phage Cp-1, were studied. Intraperitoneal therapy with LytA or high-dose Cpl-1 remarkably reduced peritoneal bacterial counts (>5 log(10) CFU/ml) compared with those for the controls. After intravenous injection, LytA was the most effective treatment.     

TaqMan实时荧光定量PCR检测肺炎链球菌

目的利用实时荧光定量聚合酶链反应（实时PCR）方法进行肺炎链球茵的检测和流行病学调查。方法用实时PCR技术扩增并检测400例临床标本的肺炎链球菌的自溶素（1yt）基因,并将其与传统的培养法进行对比。结果400例,临床标本中,实时PCR检测肺炎链球菌为阳性的有78例（阳性率为18％）,传统培养法结果为阳性的有29例（阳性率为7．25％）。结论实时PCR是一种灵敏、特异、快速的检测肺炎链球菌方法,其可用于肺炎链球菌的诊断和流行病学调查。     

外周血单核细胞中肺炎衣原体特异性抗原的检测

目的 :肺炎衣原体 (Cpn)特异性抗原检测方法的建立及其应用。方法 :分离人外周血单核细胞 (PBMC) ,用直接免疫荧光 (DIF)检测PBMC中的Cpn特异性抗原 ,同时用间接微量免疫荧光 (MIF)检测Cpn抗体。结果 :颈动脉粥样硬化病人和正常人PBMC中Cpn特异性抗原检出阳性率分别为 6 2 %和 30 % (P <0 .0 1) ;血浆中CpnIgG的检出阳性率分别为 72 %和2 8% ,P值 <0 .0 0 1;血浆中CpnIgM的检出阳性率分别为 16 %和 12 % (P值 >0 .0 5 )。结论 :PBMC中的Cpn特异性抗原和血浆中Cpn -IgG的高检出率均见于颈动脉粥样硬化病人 ,但抗原的检测具有更大的临床意义。     

血液恶性肿瘤及造血干细胞移植患者侵袭性真菌感染的早期抗原诊断实验研究

本研究评价血清1,3-β-D葡聚糖(G)和半乳甘露聚糖(GM)联合检测用于血液恶性肿瘤及造血干细胞移植患者侵袭性真菌病(IFD)早期诊断的敏感度及特异度,确定GM阳性值、探讨G/GM测定前后诊断级别的变化及GM水平与疗效的关系。用双抗体夹心酶联免疫吸附分析(ELISA)测定患者血清G和GM值。结果表明:按照实验中测定的界值,G/GM联合检测的敏感度100%,特异度65.7%,阳性预测值67.6%,阴性预测值为100%;G/GM检测后临床诊断IFD由1例上升至24例,有12例非感染者上升为拟诊IFD;治疗前GM水平维持在较高水平,抗真菌治疗有效患者的GM值呈下降趋势,无效死亡患者GM值呈上升趋势。结论:G及GM实验联合检测提高了IFD诊断的敏感度,降低了假阴性的发生,具有早期诊断价值,动态监测G/GM值的变化可作为评价疗效的指标。     

Serotype and Clonal Evolution of Penicillin-Nonsusceptible Invasive Streptococcus pneumoniae in the 7-Valent Pneumococcal Conjugate Vaccine Era in Italy

The percentage of invasive penicillin-nonsusceptible pneumococci (PNSSP) isolated in Italy in the seven-valent pneumococcal conjugate vaccine (PCV7) era moderately increased in comparison to the pre-PCV7 era. Increase of nonvaccine serotypes was observed among PNSSP. The most frequent PNSSP clones were the same as those identified in the pre-PCV7 era, although they were present in different proportions. Clonal expansion, emergence of new clones, and acquisition of penicillin resistance by established clones contributed to the maintenance of penicillin resistance.     

对居家腹膜透析患者开展健康教育的效果评价

目的 评价肾友会在居家腹膜透析患中开展健康教育的效果。方法 应用健康教育程序,向居家腹膜透析患传授腹膜透析知识及技术。结果 22位居家腹膜透析患,肾友会前,后进行腹膜透析知识书面笔试及换液技术操作考核的平均成绩有显差异（P＜0．05）,表明肾友会后患对腹膜透析知识及换流技术的掌握程度有显提高。结论 肾友会是一种对居家腹膜透析患进行相关健康教育的有效形式,具有良好的社会与经济效益。     

Nationwide Surveillance of Macrolide-Resistant Mycoplasma pneumoniae Infection in Pediatric Patients

We conducted nationwide surveillance to investigate regional differences in macrolide-resistant (MR) Mycoplasma pneumoniae strains in Japan. The prevalence of MR M. pneumoniae in pediatric patients gradually increased between 2008 and 2012. Although regional differences were observed, high levels of MR genes were detected in all seven surveillance areas throughout Japan and ranged in prevalence from 50% to 93%. These regional differences were closely related to the previous administration of macrolides.     

Pharmacokinetics and Pharmacodynamics of Nemonoxacin against Streptococcus pneumoniae in an In Vitro Infection Model

The aim of this paper was to investigate the pharmacokinetics (PK) and pharmacodynamics (PD) of nemonoxacin, a novel nonfluorinated quinolone, against Streptococcus pneumoniae in vitro. A modified infection model was used to simulate the pharmacokinetics of nemonoxacin following scaling of single oral doses and multiple oral dosing. Four S. pneumoniae strains with different penicillin sensitivities were selected, and the drug efficacy was quantified by the change in log colony counts within 24 h. A sigmoid maximum-effect (E_max) model was used to analyze the relationship between PK/PD parameters and drug effect. Analysis indicated that the killing pattern of nemonoxacin shows a dualism which is mainly concentration dependent when the MIC is low and that the better PK/PD index should be the area under the concentration-time curve for the free, unbound fraction of the drug divided by the MIC (fAUC_0–24/MIC), which means that giving the total daily amount of drug as one dose is appropriate under those conditions. When the MIC is high, the time (T) dependency is important and the valid PK/PD index should be the cumulative percentage of a 24-h period in which the drug concentration exceeds the MIC under steady-state pharmacokinetic conditions (f%T>MIC), which means that to split the maximum daily dose into several separate doses will benefit the eradication of the bacteria. To obtain a 3-log₁₀-unit decrease, the target values of fAUC_0–24/MIC and f%T>MIC are 47.05 and 53.4%, respectively.     

腹膜透析致腹腔感染病人的护理

连续性腹膜透析是终末期肾功能衰竭的一种重要治疗方法 ,它是用腹膜作为透析膜 ,依赖弥漫和超滤的作用达到清除体内过多水分和毒素的目的[1] ,从而提高病人的生活质量。但是 ,接受腹膜透析的病人出现腹腔感染的几率较高 ,有的不得不停止腹膜透析。现将我院近 10ａ来收住的 6例腹膜透析病人发生腹腔感染的原因及护理总结如下。1　一般资料本组腹膜透析并发腹腔感染者 6例 ,男 4例 ,女 2例 ,年龄32岁～ 68岁 ,平均年龄 47岁 ,其中家庭透析 5例 ,院内透析 1例。 1例为霉菌性腹膜炎 ,5例为细菌感染性腹膜炎。 2例因腹膜感染而转行血液透析 ,4例…     

Activity of Amoxicillin-Clavulanate against Penicillin-Resistant Streptococcus pneumoniae in an Experimental Respiratory Infection Model in Rats

High doses of amoxicillin, equivalent to those produced by 500- and 750-mg oral doses in humans (area under the plasma concentration-time curve), were effective against a penicillin-resistant strain of Streptococcus pneumoniae in an experimental respiratory tract infection in immunocompromised rats; this superior activity confirms the results of previous studies. An unexpected enhancement of amoxicillin’s antibacterial activity in vivo against penicillin-resistant and -susceptible S. pneumoniae strains was observed when subtherapeutic doses of amoxicillin were coadministered with the β-lactamase inhibitor potassium clavulanate. The reason for this enhancement was unclear since these organisms do not produce β-lactamase. The differential binding of clavulanic acid and amoxicillin to penicillin-binding proteins may have contributed to the observed effects.     

Bioimpedance Spectroscopy for the Detection of Fluid Overload in Chinese Peritoneal Dialysis Patients

♦ Background: Fluid overload probably contributes to the cardiovascular risk of peritoneal dialysis (PD) patients. We studied the relationship between over-hydration as determined by bioimpedance spectroscopy and dialysis adequacy, nutritional status, and arterial stiffness in Chinese PD patients.♦ Methods: We studied 122 asymptomatic prevalent PD patients: bioimpedance spectroscopy, arterial pulse wave velocity, dialysis adequacy and nutritional status were determined.♦ Results: Of the 122 patients, 88 (72.1%) had over-hydration of ≥ 1 L, while 25 (20.5%) were ≥ 5 L. Over-hydration significantly correlated with total body water (r = 0.474, p < 0.001) and extracellular water (r = 0.755, p < 0.001). Over-hydration was more severe in male and diabetic patients, and significantly correlated with Charlson’s comorbidity score, blood pressure, body mass index, body weight, peritoneal transport characteristics, and carotid-femoral pulse wave velocity. Over-hydration significantly correlated with Kt/V (r = -0.287, p = 0.016), serum albumin level (r = -0.465, p < 0.001) and malnutrition inflammation score (r = 0.410, p = 0.006), but not residual renal function.♦ Conclusion: Over-hydration is common in asymptomatic Chinese PD patients. The degree of over-hydration is particularly pronounced in patients who are inadequately dialyzed, have multiple comorbid conditions and low serum albumin levels. Over-hydration is associated with high blood pressure and arterial stiffness, and may contribute to the excessive risk of cardiovascular disease in this group of patients.