Monitoring Legionella species in hospital water systems. Link with disease and evaluation of different detection methods.

The aim of this work was to evaluate three currently available isolation methods for Legionella using water samples and swabs of a single pediatric hospital water system. Additionally, high risk patients were screened for the presence of Legionella pneumophila antigen in urine. Fifteen water samples and 11 swab samples were collected from distal sites at 18 sampling locations. The International Standard Method (PN-ISO11731-2) based on membrane filtration and direct culture of bacteria on selective media were compared with amoebic co-culture. The numbers of legionellae detected exceeded 10(2) cfu/100 ml in 50% of the samples. All the positive samples contained L. pneumophila SGs 2-14. Urine samples were obtained from 57 immunosuppressed children and screened for the presence of L. pneumophila serogroup (SG) 1 antigen by Legionella urinary antigen EIA. Of the 57 urine samples tested for the presence of Legionella pneumophila SG 1 antigen, none were positive. Our results highlight the value of combined membrane filtration and amoebic co-culture methods in detecting viable L. pneumophila strains. Direct plating of 0.2 ml water is a useful screening method for samples containing large bacterial amount.

[CMC and EBV infections in children]. / Zakazenia wirusem cytomegalii i Epsteina-Barr u dzieci.

CMV and EBV infections are common in humans. In immunocompetent persons those infections are usually asymptomatic but in immunocompromised can manifest as a severe disease. CMV is a common cause of congenital infections. It is also a frequent complication in transplant recipients. The aim of this study was to assess the prevalence of CMV and EBV infections among hospitalized children. Specific antibodies against CMV and EBV were detected in serum by ELISA test. Presence of CMV DNA was determined in leucocytes by Murex Hybrid Capture System. CMV and EBV infections were defined as the presence in serum IgM-class specific antibodies. Obtained results indicate that CMV and EBV infections are frequent in immunocompromised patients. Among patients with CMV or EBV infection, 40% have been diagnosed with cancer, most of whom with hematologic malignancies: leukemia or lymphoma. CMV and EBV coinfection was detected in 14% of infected children. Of all patients with CMV, 50% were neonates and infants. Congenital infection was diagnosed only in one case. The remaining infections were acquired during perinatal period or later.