S. Levidiotou

Viral agents of acute gastroenteritis in hospitalized children in Greece

Abstract A 6-year study of stool samples from 4604 children hospitalized for acute gastroenteritis was conducted to investigate the role of enteric viruses as a cause of gastroenteritis in north-west Greece. Rotaviruses, noroviruses, adenoviruses and astroviruses were detected in 21.35%, 4%, 3.5% and 2.35%, respectively, by enzyme immunoassays and molecular techniques. Molecular techniques enhanced overall diagnostic efficacy by 2.5%, and by c. 10% each for rotavirus and adenovirus. Rotavirus was the leading cause of viral gastroenteritis, usually associated with severe illness. Mixed infections were found in 4.4% of positive specimens, and rotavirus plus astrovirus represented the most frequent co-infection (55.5%). This first study on the epidemiology of viral gastroenteritis in Greece shows that recent advances in the diagnosis of viral enteropathogens may have only marginal effects on overall diagnostic efficacy, and thus the impact of viral agents causing sporadic gastroenteritis in public health cannot be fully evaluated.

Four-Year Experience of Use of the Cobas Amplicor System for Rapid Detection of Mycobacterium tuberculosis Complex in Respiratory and Nonrespiratory Specimens in Greece

To evaluate the experience of a clinical microbiology laboratory with a DNA amplification assay for routine detection of Mycobacterium tuberculosis, the Cobas Amplicor Mycobacterium tuberculosis (MTB) polymerase chain reaction (PCR) assay (Roche Diagnostics Systems, USA) was performed on 7,722 respiratory and 1,451 nonrespiratory specimens collected from 3,321 patients. The results were compared with those of culture in conventional Lowenstein-Jensen medium, culture in the MB/BacT system (Organon Teknika, France), and clinical investigations. A total of 240 of the 254 respiratory specimens culture positive for Mycobacterium tuberculosis were also positive in the PCR assay. Of the 7,300 culture-negative specimens, 45 (0.6%) were positive in the PCR. After detailed interpretation, the overall sensitivity, specificity, and positive and negative predictive values of the PCR assay were 84.5, 99.8, 94.1, and 99.4%, respectively, for respiratory specimens. The PCR assay was more sensitive for smear-positive respiratory specimens (97.1%) than for smear-negative respiratory specimens (48.6%). Of the 18 culture-positive (smear-negative) nonrespiratory specimens, 9 were positive in the PCR. None of the 1,384 culture-negative nonrespiratory specimens were positive in the PCR. The inhibition rates detected by the internal control of the test were 2.2% for respiratory specimens and 3.4% for nonrespiratory specimens. After resolving the discrepancies, the overall sensitivity, specificity, and positive and negative predictive values of the PCR assay were 82.5, 99.8, 94.3, and 99.4%, respectively, when compared to the results of diagnostic culture. In conclusion, the use of the Cobas Amplicor MTB-PCR assay might enable clinical microbiology laboratories with considerable previous experience in molecular biology testing to perform PCR and confirm tuberculosis infection immediately, leading to improved patient management.

Application of a Polymerase Chain Reaction Enzyme Immunoassay in Peripheral Whole Blood and Serum Specimens for Diagnosis of Acute Human Brucellosis

A simple polymerase chain reaction-enzyme immunoassay (PCR-EIA) was employed for the rapid laboratory diagnosis of human brucellosis directly from peripheral blood. Whole blood and serum specimens were collected from 243 patients with acute brucellosis as determined by blood culture, serological tests, and the patients’ clinical characteristics and from a control group of 50 healthy individuals. Diagnosis of brucellosis was established in 179 cases by isolation of Brucella spp. in blood culture and in 64 cases by clinical signs and serological investigation. Following the amplification of a 223-bp sequence of a gene that codes for the synthesis of an immunogenic membrane protein specific for the Brucella genus, the amplified product was detected in a microtiter plate by hybridization. Two hundred forty-one of the 243 patients tested had detectable Brucella DNA in either whole blood or serum specimens: 149 (61.3%) patients were positive in both whole blood and serum specimens, 43 (17.7%) were positive in serum specimens only, and 49 (20.2%) were positive in whole blood specimens only. The diagnostic specificity of the PCR-EIA assay for both specimen categories was 100%, while the sensitivity was 81.5% for whole blood specimens, 79% for serum specimens, and 99.2% for whole blood and serum specimens combined. The results suggest that the detection of Brucella DNA in whole blood and serum specimens by PCR-EIA assay is a sensitive and specific method that could assist the rapid and accurate diagnosis of acute human brucellosis.

Searching for West Nile virus (WNV) in Greece

West Nile virus (WNV), a mosquito‐borne flavivirus, has increasingly become a concern in both America and Europe due to its complex and unpredictable lifecycle. Transfusion‐associated transmission of the WNV has been well documented during the last few years. This study aimed to detect the presence of WNV in: (i) cerebrospinal fluid (CSF) specimens derived from aseptic meningitis cases in Greece and (ii) Greek blood donations. A total of 115 CSF specimens from patients suffering from aseptic meningitis and 9590 blood samples were collected from seven Greek hospitals during the periods June to October 2006 and 2007 and tested for investigational purposes. Both blood and CSF samples were tested for the presence of WNV RNA by using the PROCLEIX WNV assay. None of 115 CSF and 9590 blood donor samples was found positive according to our testing algorithms. Despite the presence of WNV in Balkan countries, WNV has not reached significant levels in Greece.

Rate of seizures in children with shigellosis.

N Roy-Chowdhury, B Deocharan, HR Bejjanki, J Roy-Chowdhury, C Koliopoulos, S Petmezaki and T Valaes, Departments of Medicine and Molecular Genetics and the Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York; The Metera Maternity Hospital, Athens, Greece. Correspondence to: Timos N Valaes, 53 Demetrakopoulo u Str., Voula, GR16673, Greece (Tel./fax. ‡30 1 899 1702, e-mail. patgval@ote net.gr)

Chlamydia trachomatis infections in Greece: first prevalence study using nucleic acid amplification tests

The present retrospective study was initiated to determine the prevalence of Chlamydia trachomatis and to assess the risk factors for infection in adult women and men presenting to general practitioners, gynecologists, dermatologists, and family-planning centers in Greece. The study was carried out in four different Greek hospital centers using highly sensitive nucleic acid amplification techniques. Altogether, 16,834 women and 1,035 men were enrolled from October 1998 to April 2004. Two types of specimens were collected from each patient: cervical swabs from women, urethral swabs from men, and first-catch urine from women and men. All specimens were examined with the Cobas Amplicor C. trachomatis polymerase chain reaction assay (Roche Molecular Systems, Branchburg, NJ, USA) or the LC × C. trachomatis ligase chain reaction assay (Abbott Laboratories, Abbott Park, IL, USA). Demographic and behavioral data were collected by clinicians using a standardized questionnaire. A total of 704 (3.9%) patients were infected with C. trachomatis. The prevalence among female patients was 3.5% and that among male patients 11.2%. Among infected patients, 88% were under 30 years of age, 71% reported more than one sexual partner, and 91% reported a new sexual partner within the last year. In conclusion, the prevalence of C. trachomatis infection in Greece is low. Young age and new and multiple sexual partners within the last year were factors consistently associated with an increased risk of chlamydial infection.

Neonatal bacteraemia: a population-based study.

The aims of this study were to explore the incidence of neonatal bacteraemia and identify the risk factors among neonatal intensive care unit (NICU) patients. The study included 3339 neonates admitted to the NICU of Ioannina University Hospital, North-Western Greece, during the 10-y period 1989-98. Logistic regression was used to assess the contribution of different risk factors to bacteraemia. A diagnosis of bacteraemia was made in 90 neonates (2.7%), 10 of whom (11%) died. Gram-negative bacilli, coagulase-negative Staphylococci and Streptococci were the most common pathogens: 42%, 34% and 17%, respectively. Premature rupture of membranes was the main risk factor for early-onset sepsis (relative risk 6.28) and respiratory distress syndrome was the main risk factor for late-onset sepsis (relative risk 5.70). The relative size of neonates for their gestational age did not appear to influence the risk of infection. Case fatality was higher for early- than for late-onset sepsis (relative risk 6.59). In conclusion, certain conditions were confirmed to predispose patients to neonatal bacteraemia; neonatal morbidity and mortality can be reduced by intervening to control these predisposing factors.

Acute-phase response to benzo[a]pyrene and induction of rat ALDH3A1

The aldehyde dehydrogenase-3A1 (ALDH3A1) enzyme, encoded by a member of the [Ah]-gene family, is dramatically increased (more than 100-fold) by benzo[a]pyrene (BaP) and other polycyclic hydrocarbons. Although much is known regarding the mechanism for the drug-metabolizing enzymes up-regulated by the Ah receptor, the physiological role of that tremendously increased ALDH3A1 enzyme activity is not yet fully clarified. The aim of this study was to identify a possible acute-phase response to different classes of xenobiotics affecting the metabolic capacity of the hepatocyte, by studying possible changes of serum acute-phase proteins (APPs) of hepatic origin, before and after BaP administration. Male Wistar rats were used in different series of experiments. The effects of BaP were estimated in terms of dose-response and time-response, with regard to the serum level of several APPs such as alpha-1-acid-glycoprotein (AAG), alpha-1-antitrypsin (AAT), C-reactive protein (CRP), and haptoglobin (HPT). In parallel experiments, levels of the same proteins have been determined after a time-dependent treatment with lipopolysaccharide (LPS). The changes in serum proteins were compared with the results of BaP or LPS administration on both hepatic ALDH3A1 and total ALDH enzyme activities. The results showed that BaP induced CRP and HPT in a time-dependent way, proportional to that caused by LPS. Additionally, ALDH3A1, CRP, and HPT were induced by BaP subacute treatment, whereas another type of ALDH inducer, phenobarbital, did not affect the levels of APPs or ALDH3A1, but did increase ALDH1A3 activity. Former studies of our group have shown that the inhibitory effects of different non-steroidal anti-inflammatory drugs (NSAIDs) on the ALDH3A1 induction were most possibly due to a decreased formation of arachidonic products like prostaglandins. Considering the changes of APPs caused by BaP, this study further supports the suggestion that the induction of ALDH3A1 is related to an atypical hepatocyte inflammation produced by xenobiotics.

Serum procalcitonin as a diagnostic tool of bacteremia

Procalcitonin (PCT) is a highly specific marker of severe bacterial infections and organ failure due to sepsis. The aim of the present study was to determine the diagnostic value of serum PCT in ICU patients with bacteremia caused by either Gram-negative or Gram-positive bacteria.