Epidemiological and clinical study of viral respiratory tract infections in children from Italy.

Impact of recently discovered viruses on epidemiology of acute respiratory tract infections (ARTI) is still unclear. We studied the impact of recently discovered human metapneumovirus (hMPV), human bocavirus (HBoV), and new coronaviruses (HCoV-NL63 and HKU1) on the global epidemiology of ARTI. From October 2006 to April 2007, 237 pediatric patients affected by ARTI were enrolled in our study. Specimens were tested for respiratory viruses by polymerase chain reaction. One hundred twenty-four out of 237 samples (52.3%) were positive for one or more viruses. Picornaviruses were the most prevalent viruses (n = 61, 43.6%), followed by respiratory syncytial virus (n = 34, 24.3%) and Adenovirus (n = 25, 17.9%); hMPV (n = 9, 6.4%) was the fourth most common virus detected. HBoV and HCoV showed a low prevalence (respectively 2.9% and 2.1%). RSV was the prevalent agent of LRTI (38%). Viruses were identified in more than 50% of the studied ARTI, providing useful information on clinical features and epidemiology of specific agents affecting children in cold months. Although routine surveillance of respiratory viruses does not seem cost-effective, continuous monitoring of ARTI etiology could be a useful tool for planning resources for the development of new vaccines and antiviral agents.

Discovery of new Mycoplasma pneumoniae antigens by use of a whole-genome lambda display library.

Mycoplasma pneumoniae is the leading cause of atypical pneumonia in children and young adults. Bacterial colonization can occur in both the upper and the lower respiratory tracts and take place both endemically and epidemically worldwide. Characteristically, the infection is chronic in onset and recovery and both humoral and cell-mediated mechanisms are involved in the response to bacterial colonization. To identify bacterial proteins recognized by host antibody responses, a whole-genome M. pneumoniae library was created and displayed on lambda bacteriophage. The challenge of such a library with sera from individuals hospitalized for mycoplasmal pneumonia allowed the identification of a panel of recombinant bacteriophages carrying B-cell epitopes. Among the already known M. pneumoniae B-cell antigens, our results confirmed the immunogenicity of P1 and P30 adhesins. Also, the data presented in this study localized, within their sequences, the immunodominant epitopes recognized by human immunoglobulins. Furthermore, library screening allowed the identification of four novel immunogenic polypeptides, respectively, encoded by fragments of the MPN152, MPN426, MPN456 and MPN-500 open reading frames, highlighting and further confirming the potential of lambda display technology in antigen and epitope discovery.

Pneumococcal disease in a paediatric population in a hospital of central Italy: a clinical and microbiological case series from 1992 to 2006.

OBJECTIVES: Streptococcus pneumoniae is frequently isolated from carrier children, but it also causes localized and invasive diseases. Increasing incidence of chemoresistance can affect the efficacy of empiric therapy and it motivates interest in primary prophylaxis. The study aims to investigate clinical and microbiological features of paediatric pneumococcal infections in an Italian province. METHODS: Retrospective clinical analysis of 640 children, hospitalized from 1992 to 2006 with one culture positive for S. pneumoniae, was performed. Chemosusceptibility tests and serotyping were carried out on isolates; statistical analysis was applied to compare variables. RESULTS: Overall, 47.8% were carriers, 49% and 3.2% had, respectively, a localized or invasive disease; S. pneumoniae aetiology accounted for 25% of meningitis and 16% of sepsis. On the total isolates, 10.2% were penicillin non-susceptible, 35.15% were erythromycin resistant, with increasing rates over years. Prevalent invasive serotypes were 1 (38.1%) and 7F (9.5%). CONCLUSIONS: The study sustains pneumococcal disease relevance in children, on the strength of a 15 year observation. Long time period can represent a limit due to population characteristics changing; a selection bias could also be present due to hospitalized only patient analysis. However, we documented variable evolution of chemoresistance and a peculiar serotype spreading, offering microbiological basis for an appropriate clinical approach.

Human bocavirus detection in an atopic child affected by pneumonia associated with wheezing.

BACKGROUND: Human bocavirus (HBoV) is a newly discovered human parvovirus. HBoV was detected in respiratory samples by PCR, but its aetiologic role in the pathogenesis of acute respiratory infectious diseases is still unclear. RESULTS: In this report, we describe an atopic child affected by pneumonia, with a past history of wheezing. A panel of bacteria and respiratory viruses were searched in the nasopharyngeal swab, only human bocavirus was detected by PCR. CONCLUSIONS: Detection of HboV, as the only microbial agent, in samples from children with wheezing and acute respiratory diseases supports the assumption that this emerging virus could have an aetiologic role in the pathogenesis of respiratory diseases.

Cryptosporidium infection: diagnostic techniques.

The aim of this study was to compare a rapid immunological test and a PCR method with the conventional morphological technique for the identification of Cryptosporidium in faecal samples. Cryptosporidium was found in five samples by Kinyoun acid-fast stain. Five samples yielded positive results on immunoassay, three of which yielded negative results on microscopy. Thus, only two patients were positive for Cryptosporidium according to both methods. PCR analysis confirmed only one sample as positive. Non-homogeneous distribution of parasites in stool samples, lack of oocysts in the tested sample and antigenic diversity among Cryptosporidium species may explain the poor agreement among the three tests. Based on our experience, microscopy test with Kinyoun stain is the best and cheapest way to detect Cryptosporidium spp. in faecal samples. With this method, we have found a 5.4% prevalence of Cryptosporidium infection in our area, similar to those reported for other regions of Italy and Europe.

The effects of age and hyperhomocysteinemia on the redox forms of plasma thiols.

We assayed the redox forms of cysteine (reduced [CSH], oxidized [CSSC], and bound to protein [CS-SP]), cysteinylglycine (CGSH; cysteinylgycine disulfide [CGSSGC] and cysteinylglycine-protein mixed disulfide [CGS-SP]), glutathione (GSH; glutathione disulfide [GSSG] and glutathione-protein mixed disulfide [GS-SP]), homocysteine (Hcy; homocystine [HcyS] and homocystine-protein mixed disulfides [bHcy]), and protein sulfhydryls in the plasma of healthy subjects (divided into 8 groups ranging in age from birth to 70 years) and patients with mild hyperhomocysteinemia associated with cardiovascular disease (heart-transplant patients) or vascular atherosclerosis, with or without renal failure. In healthy individuals, levels of disulfides and protein-mixed disulfides were more abundant than those of thiols, and those of protein-thiol mixed disulfides were higher than disulfides. Concentrations of CSH, GSH, and CGSH in the various groups had profiles characterized by a maximum over time. The concentration of Hcy was unchanged up to the age of 30 years, after which it increased. CSSC concentration increased gradually with age, whereas concentrations of the other disulfides were essentially unchanged. By contrast, the concentrations of all protein-thiol mixed disulfides, especially those with CSH, increased gradually with age. Ranks of distribution of the reduced forms changed with age (at birth, CSH > CGSH > GSH > Hcy; in 1- to 2-year-olds, CSH > GSH > CGSH > Hcy; and in 51- to 70-year-olds, CSH > CGSH = GSH > Hcy), whereas those of disulfides and protein-thiol mixed disulfides were substantially unchanged (in all age groups, CSSC > CGSSGC > GSSG = HcyS and CS-SP > CGS-SP > bHcy > GS-SP). In patients with pathologic conditions, plasma levels of disulfide forms CSSC, HcyS, CS-SP, and bHcy were significantly increased, whereas other redox forms of thiols were unchanged or showed variations opposite (increasing or decreasing) to control values. Maximal increases in disulfides and protein-thiol mixed disulfides were associated with renal failure. Our data suggest that increases in plasma bHcy concentrations in subjects with pathologic conditions were more likely the result of activation of thiol-disulfide exchange reactions between free reduced Hcy and CS-SP than of a direct action of reactive oxygen species.

Outbreak and persistence of Chlamydia pneumoniae infection in an Italian family.

We describe an outbreak of familial infection of Chlamydia pneumoniae, an etiological agent for respiratory tract infections. In a family member detection of C. pneumoniae on a pharyngeal swab by polymerase chain reaction was positive until four months after the onset of symptoms, despite a course of antibiotics known to be effective against Chlamydia species

Sternoclavicular joint infection in an adult without predisposing risk factors.

Septic arthritis of the sternoclavicular joint (SCJ) is an uncommon condition and it has been associated with numerous predisposing factors. We describe a rare case of SCJ infection due to Staphylococcus aureus in an adult without known underlying predisposing conditions and in which recovery was achieved with medical therapy alone.

Resistance determinants and clonal diversity in group A streptococci collected during a period of increasing macrolide resistance.

Susceptibility to macrolides and lincosamides was investigated with 299 consecutive nonduplicate Streptococcus pyogenes clinical isolates collected over a 6-year period (1992 to 1997) from an area of central Italy. During this period, macrolide resistance rates steadily increased (from 9% in 1992 to 53% in 1997; P < 0.001). The increase was caused by isolates with a macrolide-lincosamide-streptogramin B resistance phenotype, carrying mostly erm(B) but also erm(TR) genes, that were not detected in the first 2 years and were detected with increasing prevalence (8, 5, 26, and 37%, respectively) during the following 4 years. During the same period, the prevalence of isolates with a macrolide resistance phenotype, carrying mef(A) determinants, did not vary significantly; on average it was 13%, with modest rate fluctuations in different years and no definite trend. Molecular typing revealed a remarkable clonal diversity among susceptible and resistant isolates and a notable heterogeneity of the genetic environment of the resistance genes. The analysis of clonal diversity in relation with resistance phenotypes and genotypes revealed that increased macrolide resistance rates were due to a complex interplay of different mechanisms, with a relevant contribution played by an "epidemic" spread of genetic elements carrying the erm(B) gene among the circulating streptococcal population.

Search for Chlamydia pneumoniae genes and their expression in atherosclerotic plaques of carotid arteries.

Samples of atherosclerotic tissue from 58 patients undergoing carotid surgery were analysed by tissue culture and PCR for Chlamydia pneumoniae; PCR was performed to detect Omp1, 16S rRNA and HSP-70 genes. To understand the active pathogenic role of C. pneumoniae, a reverse transcriptase-PCR (RT-PCR) assay was applied to detect the specific RNAs expressed either in the replicative form, or in the cryptic form found in chronic infection. The C. pneumoniae omp1 gene, encoding the major outer-membrane protein (MOMP), was detected in 13 of 58 samples. Among these, the result was confirmed in 11 samples after amplification of a further target, the 16S rRNA, and the presence of the HSP-70 gene, encoding heat-shock protein 70, was revealed in only five cases. All the samples were negative for evidence of specific RNAs by RT-PCR. The presence of genomic DNA and absence of specific RNAs in atherosclerotic tissue samples suggests a lack of an active metabolic or persistent infective role for C. pneumoniae. Thus, traces of C. pneumoniae DNA in these samples could be due to a degradative pathway of the host defensive cellular and biochemical mechanisms.