Fast label-free detection of C-reactive protein using broad-band Mach-Zehnder interferometers integrated on silicon chips.

An immunosensor for fast and accurate determination of C-reactive protein (CRP) in human serum samples based on an array of all-silicon broad-band Mach-Zehnder interferometers (BB-MZIs) is demonstrated. The detection was based on monitoring the spectral shifts during the binding of CRP on the antibody molecules that have been immobilized on the sensing arms of the BB-MZIs. By employing the reaction rate as the analytical signal the assay time was compressed to few minutes. The detection limit was 2.1ng/mL, the quantification limit was 4.2ng/mL and the linear dynamic range extended up to 100ng/mL. The measurements performed in human serum samples with the developed immunosensor were characterized by high repeatability and accuracy as it was demonstrated by dilution linearity and recovery experiments. In addition, the concentration values determined were in excellent agreement with those determined for the same samples by a standard clinical laboratory method. The compact size of the chip makes the proposed immunosensor attractive for incorporation into miniaturized devices for the determination of clinical analytes at the point-of-need.

Simultaneous determination of CRP and D-dimer in human blood plasma samples with White Light Reflectance Spectroscopy.

A dual-analyte assay for the simultaneous determination of C-reactive protein (CRP) and D-dimer in human blood plasma based on a white light interference spectroscopy sensing platform is presented. Measurement is accomplished in real-time by scanning the sensing surface, on which distinct antibody areas have been created, with a reflection probe used both for illumination of the surface and collection of the reflected interference spectrum. The composition of the transducer, the sensing surface chemical activation and biofunctionalization procedures were optimized with respect to signal magnitude and repeatability. The assay format involved direct detection of CRP whereas for D-dimer a two-site immunoassay employing a biotinylated reporter antibody and reaction with streptavidin was selected. The assays were sensitive with detection limits of 25ng/mL for both analytes, precise with intra- and inter-assay CV values ranging from 3.6% to 7.7%, and from 4.8% to 9.5%, respectively, for both assays, and accurate with recovery values ranging from 88.5% to 108% for both analytes. Moreover, the values determined for the two analytes in 35 human plasma samples were in excellent agreement with those received for the same samples by standard diagnostic laboratory instrumentation employing commercial kits. The excellent agreement of the results supported the validity of the proposed system for clinical application for the detection of multiple analytes since it was demonstrated that up to seven antibody areas can be created on the sensing surface and successfully interrogated with the developed optical set-up.

Thyroid function and prevalence of anti-thyroperoxidase (TPO) and anti-thyroglobulin (Tg) antibodies in outpatients hospital setting in an area with sufficient iodine intake: influences of age and sex.

In order to examine the prevalence of thyroid disease in a hospital outpatient setting, in an area of sufficient iodine intake, serum levels of TSH, T4, T3, anti-Tg and anti-TPO antibodies were examined in 909 individuals with an age range of 12.4 to 88.5 years, participating in a checkup outpatient setting. The study was conducted in Henry Dynant Hospital located in the metropolitan area of Athens, Greece, during a 2 year period. Hormonal parameters were determined by chemiluminescence immunoassay. Overt thyrotoxicosis was found in 4.95% of the total population and subclinical thyrotoxicosis in 5.5%. Overt hypothyroidism was found in 1.43% and subclinical hypothyroidism in 4.51%. In male population, overt thyrotoxicosis was found in 4.4 % and subclinical thyrotoxicosis was also found in 4.4%. On the other hand, overt hypothyroidism was found in 1.4% and subclinical hypothyroidism was found in 3.7% in males. In female population, overt thyrotoxicosis was found in 5.2% whereas subclinical thyrotoxicosis was found in 6.0%. Overt hypothyroidism was found in 1.5% and subclinical hypothyroidism was found in 4,9% in females. Positive anti-TPO antibodies were detected more often (30.4%) than anti-Tg (15.4%) in the tested population. The positivity in both anti-TPO and anti-Tg antibodies was correlated with abnormally high TSH concentrations after the age of 50 years, especially in female population. In conclusion distinct profile of thyroid hormonal parameters was observed in inhabitants in the metropolitan area of Athens, with overt thyrotoxicosis strikingly overcome overt hypothyroidism while subclinical forms of each dysfunction also exhibit analogous results.

Colistin therapy for microbiologically documented multidrug-resistant Gram-negative bacterial infections: a retrospective cohort study of 258 patients.

It is unclear whether the effectiveness of polymyxins depends on the site of infection, the responsible pathogen, dosage, and monotherapy vs. combination therapy. We investigated colistin therapy in a large, retrospective, single-centre, cohort study. Primary analysis outcomes were infection outcome, survival and nephrotoxicity. Over a 7-year period (October 2000 to October 2007), 258 patients received intravenous (i.v.) colistin for at least 72h for microbiologically documented multidrug-resistant Gram-negative bacterial infections, comprising 170 (65.9%) Acinetobacter baumannii, 68 (26.4%) Pseudomonas aeruginosa, 18 (7.0%) Klebsiella pneumoniae, 1 (0.4%) Stenotrophomonas maltophilia and 1 (0.4%) Enterobacter cloacae. Cure of infection occurred in 79.1% of patients, nephrotoxicity in 10% and hospital survival in 65.1%. In the multivariate analysis, independent predictors of survival were colistin average daily dose [adjusted odds ratio (aOR)=1.22, 95% confidence interval (CI) 1.05-1.42] and cure of infection (aOR=9, 95% CI 3.6-23.1), whilst the proportion of creatinine change (aOR=0.21, 95% CI 0.1-0.45), Acute Physiology and Chronic Health Evaluation (APACHE) II score (aOR=0.89, 95% CI 0.84-0.95) and haematological disease (aOR=0.23, 95% CI 0.08-0.66) were associated with mortality. Effectiveness of colistin was not dependent on the type of pathogen. No independent predictors for nephrotoxicity were observed. The findings of the largest cohort study to date on i.v. colistin show that colistin is a valuable antibiotic with acceptable nephrotoxicity and considerable effectiveness that depends on the daily dosage and infection site.

Pandrug-resistant Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii infections: characteristics and outcome in a series of 28 patients.

We describe the characteristics and outcome of pandrug-resistant (PDR) Gram-negative bacterial infections (23 Klebsiella pneumoniae isolates, 3 Pseudomonas aeruginosa and 3 Acinetobacter baumannii) of hospitalised patients at a tertiary-care centre (1 January 2006-31 May 2007). The site of infection was central venous catheter-related in 5 of 24 patients with clinical infection, bacteraemia in 5, the respiratory system in 5, surgical site in 5, the urinary system in 2, the ascitic fluid in 1 and the central nervous system in one. Twenty of 24 patients with infection received an antibiotic regimen containing colistin (in combination with meropenem in 8 patients). The overall in-hospital mortality was 41.7% (10/24); 8 patients died because of the PDR infection (infection-related mortality 33.3%). Significant co-morbidity was present not only in the patients who died but also in survivors. PDR Gram-negative bacterial infections are associated with considerable mortality, although not as high as expected given the fact that the isolates were resistant to all tested antibiotics, including polymyxins. Antibiotics that are ineffective in vitro may prove life-saving for some of these patients, especially combination regimens containing colistin.

High prevalence of antibody titers against Bordetella pertussis in an adult population with prolonged cough.

BACKGROUND: Pertussis is mainly considered as a disease of childhood. However, an increasing number of adults with infection due to Bordetella pertussis is reported in the literature. METHODS: A retrospective cohort study of patients with a new origin-cough of more than 3 weeks duration who were evaluated by an internal medicine-infectious diseases group practice in Athens, Greece during the period 10/2005-12/2007 was performed; patients underwent serological testing for B. pertussis infection. RESULTS: Five hundred and fifty-four adult patients underwent B. pertussis serological testing from whom 441 had a single IgM/IgG measurement. The percentage of seropositivity in the IgM/IgG B. pertussis serological testing was 71.5% in the population studied (397/554 patients; for patients who had IgM/IgG B. pertussis serological testing in more than one occasions, only the result of the first IgM/IgG measurement was taken into account for this analysis). For the subset of patients with a single IgM/IgG measurement, the percentage of seropositivity against B. pertussis was 70.7% (312/441 patients). CONCLUSIONS: B. pertussis infection should be considered as a significant pathogenic infection in a significant proportion of adult patients presenting a new origin-cough of more than 3 weeks duration. In order to reduce the burden of pertussis disease in adults as well as transmission of pertussis in children, booster vaccination is recommended for adolescents and adults.

Association of sleep apnea severity and obesity with insulin resistance, C-reactive protein, and leptin levels in male patients with obstructive sleep apnea.

Obesity is the major confounding factor in the relationship between obstructive sleep apnea and increased risk for cardiovascular disease. The aim of the study was to investigate the association of sleep apnea severity with insulin resistance, leptin, and CRP levels in a cohort of male patients. Sixty-seven men referred to our sleep laboratory for evaluation of suspected obstructive sleep apnea syndrome (OSAS) were divided into three groups according to apnea severity: non-OSAS group (n=15), mild to moderate OSAS group (n=26), and severe OSAS (n=26). Insulin resistance was estimated by the homeostasis model assessment method. HOMA values were similar in the three groups: (3.2+/-2.2 vs. 3.3+/-1.8 vs. 3.6+/-1.5, respectively, p=0.71). Leptin levels were higher in the mild to moderate OSAS group (23.1+/-21.8 ng/ml, p<0.05) and in the severe OSAS group (20.2+/-17.5 ng/ml, p<0.05) than in the non-OSAS group (9.4+/-6.4 ng/ml). CRP levels were significantly higher in severe sleep apnea (0.35+/-0.3 vs. 0.19+/-0.1 mg/dl, p<0.05). In multiple regression analyses, waist-to-hip ratio (WHR) was the most significant determinant of HOMA estimation for insulin resistance. WHR and the percentage of total sleep time spent with hypoxemia (%TST with SaO2 <90%) were significant predictors for leptin levels, while body mass index (BMI) and the %TST with SaO2 <90% were the best predicting parameters for CRP levels. Insulin resistance estimated by the HOMA method in male patients with OSAS was not associated with sleep apnea severity independent of obesity. The severity of nocturnal hypoxemia was associated with leptin and CRP levels independent of obesity.

Case report: parotid abscess due to Salmonella enterica serovar Enteritidis in an immunocompetent adult.

There are reports of increasing incidence of focal extra-intestinal infections from non-typhoidal salmonellae during the past two decades. We present the first case of a parotid abscess caused by Salmonella enterica serovar Enteritidis (S. Enteritidis) in an apparently immunocompetent adult without other abnormality of the parotid glands. A 58-year-old man was admitted to our hospital because of a 3-day history of fever and painful swelling of the right parotid gland. His medical history was unremarkable. A CT scan revealed an abscess of the right parotid. S. Enteritidis was isolated from a sample of fluid aspirated from the parotid abscess under ultrasound guidance. The stool, urine, and blood cultures were negative. The patient was treated with ciprofloxacin 500 mg per os every 12 h for 10 days, with complete remission of symptoms. The infection did not recur during 3 years of follow up. Our case report adds to the literature regarding the extra-intestinal infections with S. Enteritidis, a common non-typhoidal salmonellosis.

Increased alpha-subunit response coexist with increased TSH response to TRH test in healthy individuals.

OBJECTIVE: The alpha-subunit (Alpha-SU) response to TRH was studied to examine the response of alpha-SU under TRH stimulation in normal situation. METHODS: Thirty seven healthy individuals were included in the study. They were divided into two groups according to the data taken: A with TSH equal or more than seven fold the basal values (0: 3.14+/-1.2 microU/ml., 30 after TRH: 20.22+/-4.6 microU/ml) and B with TSH 2 to 6 fold the basal values (0: 0.5+/-0.1 microU/ml., 30 after TRH: 2.9+/-0.5 microU/ml). Both groups exhibited similar FT3 and FT4 levels. RESULTS: In group A, prolactin displayed a 3 fold increase from the basal values, whereas alpha-SU increased 4 fold with a difference being statistically significant (p<0.001). In contrast, in group B individuals neither prolactin nor alpha-SU exhibited any significant difference from the basal values. CONCLUSION: The expression of alpha-SU upon TRH stimulation is dependent on the TSH basal values.

Secular trends of antimicrobial resistance of blood isolates in a newly founded Greek hospital.

BACKGROUND: Antimicrobial resistance is one of the most challenging issues in modern medicine. METHODS: We evaluated the secular trends of the relative frequency of blood isolates and of the pattern of their in vitro antimicrobial susceptibility in our hospital during the last four and a half years. RESULTS: Overall, the data regarding the relative frequency of blood isolates in our newly founded hospital do not differ significantly from those of hospitals that are functioning for a much longer period of time. A noteworthy emerging problem is the increasing antimicrobial resistance of Gram-negative bacteria, mainly Acinetobacter baumannii and Klebsiella pneumoniae to various classes of antibiotics. Acinetobacter baumannii isolates showed an increase of resistance to amikacin (p = 0.019), ciprofloxacin (p = 0.001), imipenem (p < 0.001), and piperacillin/tazobactam (p = 0.01) between the first and second period of the study. CONCLUSION: An alarming increase of the antimicrobial resistance of Acinetobacter baumannii isolates has been noted during our study.