Reduction of biofilm formation with trisodium citrate in haemodialysis catheters: a randomized controlled trial.

BACKGROUND: Formation of an intraluminal microbial biofilm is noted to play a significant role in the development of catheter-related infections (CRIs). Recently, it has been demonstrated that trisodium citrate (TSC) has superior antimicrobial effects over heparin for catheter locking. In this randomized controlled trial, we compared the influence of catheter locking with heparin and TSC on the in vivo intraluminal biofilm formation in haemodialysis catheters. METHODS: Six patients were studied from the time of catheter insertion for haemodialysis treatment. They were randomly assigned to TSC 30% or heparin 5000 U/ml for catheter locking for the duration of 1 month. After elective guidewire exchange of the catheter, the locking solution was also changed. After removal, catheters were dissected in three segments and examined by standardized scanning electron microscopy (SEM) to assess quantitative biofilm formation. Furthermore, standardized cultures of all segments were performed to identify any microorganisms. RESULTS: In catheters filled with TSC, the average coverage by biofilm was 16% versus 63% in the heparin group (P < 0.001). A total of eight subsegments were associated with local catheter infection in the patients who were randomized to heparin locking versus three subsegments who were assigned to TSC (P < 0.05). CONCLUSIONS: Our study demonstrates that using TSC 30% for catheter locking reduces the formation of microbial biofilm in haemodialysis catheters and culture-positive colonization. It is likely that this is the explanation for the observed prevention of CRIs by TSC locking.

[Dengue infection with fatal ending]. / Dengue-infectie met fatale afloop.

A 54-year-old man was admitted with fever following a trip to St. Maarten in the Dutch Antilles, from where he had returned 6 days earlier. One year prior to this he had been treated on an Intensive Care Unit for a severe influenza A infection. Physical examination revealed remarkably cold extremities, furthermore there was metabolic acidosis, extreme haemoconcentration, prolongation of prothrombin time and activated partial thromboplastin time. His clinical condition deteriorated rapidly and he died the day after admission. Neither IgG nor IgM antibodies against dengue were found, but PCR on dengue virus RNA was positive. Over past decades there has been a strong increase in the number of dengue virus infections in travellers returning from Southeast Asia, Central and South America, the Caribbean and Africa. Whilst in general a primary dengue virus infection does not result in severe disease, this case illustrates the potentially fatal consequences of dengue in travellers.

Effectiveness and cost-effectiveness of a pharmacy-based screening programme for Chlamydia trachomatis in a high-risk health centre population in Amsterdam using mailed home-collected urine samples.

In order to increase case-detection of Chlamydia trachomatis (CT) in a multicultural, low-income and high-CT-prevalence neighbourhood, a novel approach was piloted in collaboration with the pharmacy of the health centre. During a two-year period, women aged 15-29 years who collected their contraceptives at the pharmacy were offered CT-test materials. Home-collected urine could be mailed to the laboratory and the general practitioner received the results. Nine percent of respondents were CT-positive (14% among 15-24 year-olds). There was a strong association with Surinamese/Antillean background. Uptake of the programme was low (27%). Net cost per pelvic inflammatory disease prevented ranged from cost-saving up to 3872 Euros in a low complication rate/high testing cost scenario. Faced with higher risk, but low participation rates, active case-detection of CT-infections in 'high-prevalence-areas' needs a concerted approach by different providers and community organizations, both in secondary and primary prevention. Pharmacists can contribute if proper liaison is made with primary care providers and/or public health services for (partner-)treatment, counselling and comprehensive sexual health care.

Hepatitis A virus immunity and seroconversion among contacts of acute hepatitis A patients in Amsterdam, 1996-2000: an evaluation of current prevention policy.

OBJECTIVES: We evaluated the hepatitis A virus (HAV) control policy (hygienic precautions and passive immunization with immune globulin) for "household contacts" (defined as all people who lived in the same house and who shared the same toilet with the patient, people who took care of an HAV-infected child, and sexual partners of the patient) of acute hepatitis A patients between 1996 and 2000. METHODS: We examined the characteristics and the serological outcomes of household contacts. All susceptible contacts were invited for retesting 6 weeks after they received immune globulin. RESULTS: Of 1242 contacts of 569 HAV patients, more than 50% (n = 672) were found to be HAV immune. Among the remaining contacts, 161 (28.2%) had a concurrent infection, and 86 of these individuals were symptomatic. The remaining 409 susceptible contacts received immune globulin, with 186 (45%) returning for retesting 6 weeks later (64 [34%] were infected, but only 12 had symptoms). CONCLUSIONS: Immune globulin does not protect all household contacts from HAV infection; however, it attenuates symptoms and effectively reduces further HAV transmission.

Much gained by integrating contact tracing and vaccination in the hepatitis B antenatal screening program in Amsterdam, 1992-1999.

BACKGROUND/AIMS: Hepatitis B control in Europe concentrates on antenatal screening to reduce vertical transmission. To reduce horizontal transmission and the pool of infectious individuals, the Municipal Health Service of Amsterdam integrated tracing and immunising of contacts in the antenatal screening program. METHODS: An eight year (1992-1999) descriptive study of this public health program, where contacts are tested for serological markers of previous infection, and vaccination is offered to susceptible contacts. Chronically infected contacts are counselled and referred for treatment if justified. RESULTS: For 738 newly identified women testing positive for the hepatitis B surface antigen, 1219 contacts were reported; 1100 (90.4%) contacts participated, 476 (43%) had serological markers of previous infection, of whom 119 (25%) were infectious. Of 603 eligible contacts, 568 (94%) completed the vaccination series. Country of origin was an independent predictor of contact participation and compliance with completion of the vaccination series. Postvaccination titres for antibodies against the surface antigen were below 10 IU/L in 4.5% of contacts under 30, in 12.2% of those over 30. CONCLUSIONS: Tracing and immunising susceptible contacts of women screened as HBsAg-positive, should be an integral component of any country's HBV control program.

Nasopharyngeal carriage of potential bacterial pathogens related to day care attendance, with special reference to the molecular epidemiology of Haemophilus influenzae.

Nasopharyngeal carriage of Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis was studied in 259 children attending day care centers (DCC) in Amsterdam, The Netherlands, and in 276 control children. The DCC children were sampled a second time after 4 weeks. Carriage rates for DCC children and controls were 58 and 37% for S. pneumoniae, 37 and 11% for H. influenzae, and 80 and 48% for M. catarrhalis, respectively. No increased antibiotic resistance rates were found in strains isolated from DCC children. All H. influenzae isolates were typed by random amplified polymorphic DNA (RAPD) analysis. Evidence for frequent transmission of H. influenzae strains within DCC was found. In the control group only two isolates (4%) displayed identical RAPD types versus 38% of strains from DCC children. Colonization with H. influenzae appeared to be short-lived in these children; more than half of the children harboring H. influenzae in the first sample were negative in the second sample, whereas most children still positive in the second sample had a different genotype than in the first sample. Of the newly acquired strains in the second sample, 40% were identical to a strain that had been found in a child in the same DCC in the first sample. DCC are to be considered epidemiological niches with a high potential for the spread of pathogenic microorganisms.