Correlation between cyclophosphamide-induced viral susceptibility and depletion of Junin virus-induced suppressor populations.

In contrast to lymphocytic choriomeningitis virus, another arenavirus, Junin virus (JV), the etiologic agent of Argentine hemorrhagic fever, when inoculated into suckling mice, induces lethal meningoencephalitis characterized by a delayed-type hypersensitivity (DTH)-like immune response. However, the adult BALB/c mouse is resistant to infection and no DTH reaction can be seen. This different viral sensitivity may be related to the development of an antigen non-specific DTH-suppressor cell pathway at work in the adult mouse. When the resistant mice are treated with cyclophosphamide (Cy) (50 mg/kg each dose) given at days -1,+1,+4 (zero: infection day), animals become susceptible and develop DTH reaction in brain that leads to death. We analyze the influence of the timing of Cy administration on the suppressor system developing after infection. It was found that Cy depletes the previously described JV-induced suppressor populations (Tsv) but a new suppressor cell (Tsv*) is disclosed bearing the Thy 1+ Ly1+2- phenotype which is unable to depress DTH in Cy-treated animals. With only two doses of Cy corresponding to days -1 and +1, the target of Tsv* cells is depleted but the third dose is still required to achieve full depletion of Tsv cells which are able to employ the Cy-resistant antigen-specific suppressor cells as targets. Since the Cy treatment is able to deplete the Tsv population together with the target of Tsv* cells, animals became unable to regulate lethal DTH reaction. Thus, a cellular explanation for an empirically established Cy schedule able to abrogate the adult mouse resistance to JV is proposed.     

Changes in Streptococcus pneumoniae serotypes causing invasive disease with non-universal vaccination coverage of the seven-valent conjugate vaccine

The pneumococcal seven-valent conjugate vaccine (PCV7) has been administered in Portugal since late 2001 through the private sector. To evaluate the impact of PCV7 use, the serotypes and antimicrobial susceptibility of pneumococci causing invasive disease in Portugal during 2003–2005 were determined and compared with available data for the period 1999–2002. Changes in serotype distribution compatible with the introduction of PCV7 were shown for children ≤5 years of age from 2003 onwards and for adults from 2004 onwards. PCV7 use with coverage of 43% of children with four doses in the 2004 birth cohort, although substantially below universal coverage, seems to have contributed to greatly reducing the proportion of invasive infections due to vaccine serotypes  4, 6B, 14 and 23F. Similarly, significant indirect effects on the serotype distribution of pneumococci causing infections in adults were noted, with reductions in the proportion of invasive infections caused by serotypes  4, 5 and 14. These changes were accompanied by an increase in the proportion of two non-vaccine serotypes: 19A isolates in all age groups and 7F isolates in adults. Whereas serotypes  6B, 14 and 19A were associated with multidrug resistance, isolates expressing serotypes  4 and 7F were fully susceptible for the most part. There were no changes in the proportion of resistant isolates within each serotype and, in spite of the changes in serotype prevalence, there was not an overall reduction in the proportion of infections caused by resistant pneumococci.     

A European perspective on intravascular catheter-related infections: report on the microbiology workload, aetiology and antimicrobial susceptibility (ESGNI-005 Study)

The laboratory workload, microbiological techniques and aetiology of catheter-related infections in European hospitals are mostly unknown. The present study (ESGNI-005) comprised a 1-day (22 October 2001), laboratory-based, point-prevalence survey based on a questionnaire completed by microbiology laboratories in European (European Union (EU) and non-EU) hospitals. Also included were questions requesting retrospective information for the year 2000. In total, 151 hospitals from 26 European countries participated, of which 78.1% were teaching institutions. Overall, the estimated population served by these institutions was 121,363,800, and the estimated number of admissions during 2000 was 6,712,050. The total number of catheter tips processed during 2000 was 142,727, or 21/1,000 admissions, of which 23.7% were considered to be positive in the institutions using semiquantitative or quantitative techniques. Overall, EU centres received significantly more catheter tip samples/1,000 admissions and had a significantly higher rate of 'positivity' (p < 0.0001) than non-EU centres. Of the institutions surveyed, 11.4% (7.2% in EU countries and 23.7% in non-EU countries; p 0.04) used only qualitative techniques for catheter tip sample processing. On the day of the study, 167 microorganisms were recovered from significant catheter tip cultures (122 patients), of which Gram-positive bacteria represented 70.7%, Gram-negative bacteria 22.2%, and yeasts 7.2%. The five most common microorganisms were coagulase-negative staphylococci, Staphylococcus aureus, Candida spp., Enterococcus spp. and Pseudomonas spp. Overall, 19% of catheter tip cultures were polymicrobial. In the case of S. aureus, 40% of isolates were resistant to oxacillin, as were 63.4% of coagulase-negative staphylococcus isolates. Of 37 Gram-negative isolates, 35% were resistant to cefotaxime, 31% to ceftazidime, and 27% to ciprofloxacin. Imipenem and cefepime had the lowest reported rates of resistance (11%).     

Allergy, asthma and markers of infections among Albanian migrants to Southern Italy

BACKGROUND: Studies of immigrants represent an useful tool to determine the relative relevance of environmental vs genetic factors in causing the reported rapid increase of the prevalence of sensitization and allergic diseases. METHODS: A total of 152 Albanian migrants to Southern Italy responded to a questionnaire based on the European Community Respiratory Health Survey (ECRHS) and 139 of them underwent skin prick test, and 61 serological assays for total IgE and IgG antibodies against Toxoplasma gondii (TG), herpes simplex virus 1 (HSV-1), hepatitis A virus (HAV) and Helicobacter pylori (HP). RESULTS: Reported asthma was rare (2/152; 1.3%) and reported nasal allergies rather frequent (24/152; 15.8%). Sensitization to common inhalant allergens occurred in 27/139 (19.4%) subjects. The frequency of skin sensitization to pollen (P = 0.003) and that of hay fever (P = 0.004) increased with the time spent in Apulia. All the 61 sera had antibodies against HAV, 59/61 (96.7%) against HSV-1, 48/61 (78.7%) against HP and 34/61 (55.7%) against TG. The prevalence of skin sensitization and hay fever symptoms were correlated to the duration of residence in Southern Italy. CONCLUSIONS: Data presented indicate that Albanian migrants to Italy, in spite of the low prevalence of allergic diseases and sensitization in their country of origin, manifest with time an increasing prevalence of sensitization to local allergens and nasal symptoms after immigration to Italy. This would suggest a permanent role of allergen exposure and lifestyle factors in influencing the appearance of sensitization and symptoms of allergic diseases.     

Detection of bloodstream pathogens in a bacille Calmette-Guérin (BCG)-vaccinated pediatric population in Malawi: a pilot study

Children in Malawi receive bacille Calmette-Guérin (BCG) vaccination within the first 3 days of life. Thus, we hypothesized that Malawian children infected with the human immunodeficiency type 1 virus (HIV-1) might be particularly vulnerable to dissemination of the BCG Mycobacterium bovis strain with which they were vaccinated. Following informed consent by parents, we studied children admitted to a Malawi general hospital during the 1998 wet and dry seasons. Blood from cohorts of acutely ill children was cultured for bacteria, including mycobacteria, and fungi, and tested for anti-HIV-1 antibodies. It was shown that non- typhi Salmonella and Escherichia coli were the predominant bloodstream pathogens during the wet and dry seasons, and that bloodstream dissemination of the BCG M. bovis strain is uncommon in HIV-1-infected children who receive the BCG vaccine.     

Developmental regulation of type 1 and type 3 interferon production and risk for infant infections and asthma development

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High variability in viral load in cerebrospinal fluid from patients with herpes simplex and varicella-zoster infections of the central nervous system

Infections of the central nervous system (CNS) caused by herpes viruses can result in severe diseases, often with a fatal outcome. In this study, the viral load in the cerebrospinal fluid (CSF) of patients with herpes simplex or varicella-zoster infections of the CNS was measured using a quantitative real-time PCR. The results suggest a high variability in viral load, with relatively mild disease associated with a high viral load in CSF and vice versa. Determination of the viral load in CSF does not therefore seem to be useful in assessing the prognosis of disease caused by these viruses.     

Effectiveness and limits of antimicrobial treatment on seminal leukocyte concentration and related reactive oxygen species production in patients with male accessory gland infection

To evaluate whether bacteriological cure, sperm outcome, spontaneous pregnancy rate and white blood cell (WBC)-related reactive oxygen species (ROS) production were related to the extent of the infection and to an intermittent and repetitive antimicrobial treatment, 122 patients with bacterial [>10(5) colony-forming units (CFU)/ml] male accessory gland infections (MAGI) were studied. According to ultrasound criteria, patients had prostatitis (PR, n = 52), prostatovesiculitis (PV, n = 32) or prostatovesiculoepididymitis (PVE, n = 38). Each group was further subdivided into two subsets: one subset (PR, n = 40; PV, n = 20; PVE, n = 25) was given ofloxacin or doxycycline for 14 consecutive days per month for 3 months; the other subset (PR, n = 12; PV, n = 12; PVE, n = 13) received no treatment. The female partners were also treated. All patients were evaluated before, during (1 and 3 months) and after (3 months) treatment. The bacteriological cure rate was the highest (92.5%) after the third antibiotic course in PR, followed by PV (70.4%), and the lowest in PVE (52.0%). At 3 months after therapy discontinuation, some sperm parameters, seminal WBC concentration and ROS generation (assessed in the 45% Percoll fraction) were ameliorated in PR and PV, whereas no improvement occurred in patients with PVE, except for the percentage of coiled tails. Antibiotic treatment in PR and PV patients led to positive effects on sperm output and spontaneous pregnancy rate (40%) by removing pro-oxidant noxae (microbial and/or WBC-related ROS production). The persistent infertility, dyspermia and sperm-derived ROS overproduction in PVE may relate to a significant percentage of antibiotic-independent re-infection and/or to low antioxidative epididymal properties, which persisted following antimicrobial treatment.