Carla Cellesi

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. J. Med. Virol. 81:750–756, 2009

Staphylococcus aureus nasal carriage in the community: a survey from central Italy.

Recently, concern has increased regarding the spread of methicillin-resistant Staphylococcus aureus (MRSA) in the community. We studied 812 subjects from central Italy to establish the rates of nasal carriage of S. aureus, and antibiotic susceptibility patterns, in the community. The prevalence of S. aureus nasal carriage was 30.5%. Only one subject, with predisposing risk factors for acquisition, was identified as carrier of MRSA (prevalence of 0.12%). The presence of MRSA in the community of our area still appears to be a rare event. Among methicillin-susceptible S. aureus (MSSA) isolates, a surprisingly high rate (18%) of resistance to rifampin was observed.

Immunity to diphtheria in a sample of adult population fron central Italy

A sample of 643 healthy subjects from central Italy aged 20 to 80, were screened for diphtheria antitoxin. Serum diphtheria antitoxin was assayed by a new passive haemagglutination technique using turkey red blood cells sensitized with diphtheria toxoid, after having performed a correlation study between this technique and the reference in vivo neutralization test. Of the studied population 26.7% showed a lack of serum antitoxin titres considered to be protective. The rate of susceptible subjects increased with age, showing the highest value (38.9%) in the sixth decade of age. Males proved less protected than females; 53.2% of the male population aged 50-59 were lacking a protective anti-diphtheria immunity. On the basis of present results, a periodical revaccination of the entire adult population with reduced doses of diphtheria toxoid would be advisable.

Resistance Determinants and Clonal Diversity in Group A Streptococci Collected during a Period of Increasing Macrolide Resistance

ABSTRACT 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.

Age-Dependent Seroprevalence of Toscana Virus in Central Italy and Correlation with the Clinical Profile

ABSTRACT In order to estimate the antibody prevalence rates for Toscana virus (TOSV) among children and adults, we evaluated the seroprevalence of TOSV in a population (n = 2,737) living in Tuscany during the period of 1999 to 2006. The seroprevalence rate was 19.8% in adults and 5.8% in children, showing an age-dependent increase in TOSV-specific immunity. Meningitis due to TOSV infection was more frequent in adults than in children.

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.

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.

Possibility of reinfection after immunisation with RA 27/3 live attenuated rubella virus

SummaryA serological study was carried out on 527 girls immunized with RA 27/3 rubella vaccine. Data from all scheduled serum samples over a 5-year follow-up were available for 102 vaccinees, 10 (9.8%) of whom showed evidence of reinfection during the 5th year after immunisation, a year in which there was a rubella outbreak in the Siena area (Italy). We examined in greater detail the serological responses of these vaccinees after reinfection and the consequent implications pertinent to the duration of the protective immunity.

Muscular-skeletal cryptococcosis in a patient with idiopathic CD4+ lymphopenia

A healthy 27-year-old woman presented, four months after childbirth, ingravescent pain and claudication of the left lower limb. Magnetic Resonance Imaging of the lumbosacral and iliac regions showed widespread muscular-skeletal lesions. The patient underwent surgery; Cryptococcus neoformans was isolated from surgical samples. Liposomal amphotericin B, fluconazole and itraconazole were administered. Laboratory findings showed lymphocytopenia, with reduction of CD4+ lymphocytes (23 cells per cubic millimeter) in the absence of HIV infection and any other defined immunodeficiency. This is a rare case of muscular-skeletal cryptococcal infection isolated in a subject affected with idiopathic CD4+ lymphocytopenia.

Erythromycin Resistance in Streptococcus pyogenes and Macrolide Consumption in a Central Italian Region

AbstractBackground:The study investigated macrolide resistance in Streptococcus pyogenes in a central Italian area from 2001 to 2006 and the possible correlation between antibiotic consumption and fluctuations of resistance percentages.Materials and Methods:Macrolide and lincosamide susceptibility of 1,419 S. pyogenes isolates was tested by Kirby Bauer method. Macrolide consumption was valuated as defined daily dose/1,000 inhabitants per day (DID), according to the World Health Organization anatomic therapeutic chemical classification. Spearman’s correlation coefficient was used to assess the association between resistance and use of (1) all macrolides pooled, (2) once daily, (3) twice daily, and (4) three times daily dosage regimens.Results:In total, 320 strains (22.6%) were erythromycinresistant, 11.4% with the M phenotype and 11.2% with the MLS phenotype. There was a significant decrease in erythromycin resistance during the study period—from 28.1% in 2001 to 15.6% in 2006 (p < 0.01). No significant correlation was found between erythromycin resistance and local overall macrolide consumption, neither during the same year nor during the previous year. In contrast, a significant correlation was found between resistance rates and oncedaily macrolide use during the preceding 6 months in Siena r = 0.747, p = 0.008).Conclusion:The known greater selective effect of longacting agents could establish a pressure outcome, resulting in a specific local epidemiology during a relatively short time gap.