Outdoor particulate matter and childhood asthma admissions in Athens, Greece: a time-series study.

BACKGROUND: Particulate matter with diameter less than 10 micrometers (PM10) that originates from anthropogenic activities and natural sources may settle in the bronchi and cause adverse effects possibly via oxidative stress in susceptible individuals, such as asthmatic children. This study aimed to investigate the effect of outdoor PM10 concentrations on childhood asthma admissions (CAA) in Athens, Greece. METHODS: Daily counts of CAA from the three Children's Hospitals within the greater Athens' area were obtained from the hospital records during a four-year period (2001-2004, n = 3602 children). Mean daily PM10 concentrations recorded by the air pollution-monitoring network of the greater Athens area were also collected. The relationship between CAA and PM10 concentrations was investigated using the Generalized Linear Models with Poisson distribution and logistic analysis. RESULTS: There was a statistically significant (95% CL) relationship between CAA and mean daily PM10 concentrations on the day of exposure (+3.8% for 10 microg/m3 increase in PM10 concentrations), while a 1-day lag (+3.4% for 10 microg/m3 increase in PM10 concentrations) and a 4-day lag (+4.3% for 10 microg/m3 increase in PM10 concentrations) were observed for older asthmatic children (5-14 year-old). High mean daily PM10 concentration (the highest 10%; >65.69 microg/m3) doubled the risk of asthma exacerbations even in younger asthmatic children (0-4 year-old). CONCLUSIONS: Our results provide evidence of the adverse effect of PM10 on the rates of paediatric asthma exacerbations and hospital admissions. A four-day lag effect between PM10 peak exposure and asthma admissions was also observed in the older age group.

Inflammatory bowel disease in children: the role of a positive family history.

OBJECTIVES: The aim of this study was to evaluate any potential influence of a family history of inflammatory bowel disease (IBD) on the clinical phenotypes and the course of IBD in children. METHODS: In this retrospective study, the notes of 411 children with the diagnosis of IBD, 244 (59.4%) with ulcerative colitis, 129 (31.4%) with Crohn's disease and 38 (9.2%) with IBD unclassified, who were admitted to our department between 1 January 1981 and 31 December 2007 were reviewed. The aim was to assess the prevalence of familial IBD and its impact on the age of disease onset, clinical phenotypes according to the Montreal classification, course and outcome of disease. The control group consisted of IBD children without a family history of IBD, who were admitted to the hospital during the same time period. RESULTS: Thirty five (8.5%) children had a family history of IBD, (ulcerative colitis 6.6%, Crohn's disease 10.9% and IBD unclassified 13.2%). Sixty-eight percent of the 22 pairs of first-degree relatives were concordant for the clinical phenotype of disease. Significantly, more children with familial IBD had symptom onset and/or disease diagnosis before 5 years of age compared with sporadic IBD (P = 0.01 and P = 0.014, respectively); however, no differences were seen in sex, clinical phenotypes, need for aggressive treatment and/or surgery. CONCLUSION: Children with familial IBD had earlier onset of disease compared with those with sporadic IBD. However, this had no significant impact on the clinical phenotypes, the course and/or the outcome of disease.

Febrile seizures and primary human herpesvirus 6 infection.

Primary human herpesvirus 6 infection is acquired mainly during the first two years of life and is often associated with febrile seizures. The aim of the present study was to investigate in Greece the frequency and clinical characteristics of primary human herpesvirus 6 (HHV-6) infection in hospitalized children with febrile seizures. Children aged from 6 months to 5 years without known neurologic disease were examined for primary HHV-6 infection, by real-time polymerase chain reaction in acute-phase plasma and by indirect immunofluorescent assay for antibody titers in acute and convalescent serum. Of 65 children included in the analysis, 55 experienced the first febrile episode of seizures and 10 the second. Primary HHV-6 infection was verified in 10 of 55 children with a first febrile episode (18%), whereas none of the 10 children with a second episode of seizures had primary HHV-6 infection. Eight children were infected with HHV-6 type B and two with type A. None of the 85 control subjects had primary HHV-6 infection, but 49% had immunoglobulin G antibodies against the virus. These findings suggest that primary HHV-6 infection is frequently associated with febrile seizures in children in this geographic region and should be considered, especially for a first episode of febrile seizures.

Prevalence and characterization of class 1 integrons in Escherichia coli of poultry and human origin.

A prospective study was conducted to determine the prevalence and the gene-cassette content of class 1 integrons in Escherichia coli of poultry and human origin. A total of 235 E. coli isolates were examined; 65 were derived from farm poultry, 80 from hospitalized, and 90 from nonhospitalized patients. Susceptibilities to a range of antimicrobial agents were determined by disk diffusion. Int1-specific polymerase chain reaction, conserved-segment polymerase chain reaction, and DNA sequencing were used to determine the presence, length, and content of integrons. The relatedness among the isolates was examined by pulsed-field gel electrophoresis of XbaI digests of genomic DNA. The integron carriage rate for poultry isolates was 49.2%, whereas the carriage rate for hospital isolates was 26.2% and for community 11.1%. Multidrug resistance (resistance to three or more classes of antibiotics) phenotypes were observed in 96.8% of the integron-positive isolates, whereas only 34.9% of nonintegron-carrying organisms were multidrug resistant (p < 0.001). Seven integron types ranging in size from 663 to 2674 bp were identified; six types were observed in poultry isolates, five in hospital, and three in community isolates. Each integron type carried a distinct gene-cassette combination. The most prevalent gene cassettes belonged to the aad and dfr families. Identical integrons were detected in E. coli of human and poultry origin. A large reservoir of integrons exists in E. coli of poultry origin. The horizontal transfer of class 1 integrons among bacteria of poultry and human origins may contribute in the dissemination of antimicrobial resistance.

Macrolide resistance in Streptococcus pyogenes: prevalence, resistance determinants, and emm types.

To investigate the antimicrobial resistance trends and the distribution of emm types of group A streptococci (GAS), we examined 1160 clinical isolates of GAS collected between 2003 and 2006. Susceptibilities to commonly used antimicrobial agents were determined by Etest, and macrolide resistance genes were detected by polymerase chain reaction (PCR). GAS isolates were typed by polymerase chain reaction PCR and sequencing of emm gene. The rates of resistance to erythromycin (ERY), clindamycin, azithromycin, tetracycline, and chloramphenicol were 14.9%, 1.4%, 14.9%, 18.9%, 0.6%, respectively. None of the isolates exhibited resistance to penicillin, ceftriaxone, linezolid, moxifloxacin, rifampicin, or vancomycin. Macrolide resistance increased from 12.1% in 2003 to 18.8% in 2006 (P = 0.02). Of 173 ERY-resistant GAS isolates, 93 (53.7%) harbored the mefA gene, 70 (40.4%) the ermA, and 10 (5.8%) the ermB. Eighty percent of the observed emm types are covered by the proposed 26-valent GAS vaccine. Among 173 ERY-resistant isolates, the predominant emm types were 12 (19.5%), 77 (17.9%), and 4 (16.8%), and among 770 ERY-susceptible isolates, the predominant types were 1 (18.8%), 12 (17.5%), 28 (13.8%). The observed antimicrobial resistance trends and the distribution of specific emm types have implications in guiding empiric therapy and in developing vaccine strategies to prevent GAS infections.