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Biomedical subjects

W D Hendriks

Publications and source records attributed to W D Hendriks.

At least 19 recordsLinked to original sources

[Outbreak of methicillin-resistant Staphylococcus aureus (MRSA) in the Rijnmond region: the largest outbreak in the Netherlands].

UNLABELLED: EPIDEMIC: The annual number of new MRSA isolates in the Netherlands tripled in 2002 compared with previous years. This increase was in part due to a MRSA outbreak in the Rijnmond region. The outbreak occurred in two merged hospitals and is the largest ever to occur in the Netherlands. From November 2001 till June 2003 MRSA was isolated from 381 patients and 113 hospital employees. The worst affected departments were Surgery and Internal Medicine. One MRSA strain (pulsed-field gel electroforesis (PFGE) type 16) remained initially unrecognised and was therefore able to spread unnoticed. Soon two additional epidemic MRSA strains (types 37 and 38) were discovered. DISCUSSION: Multiple factors played a role in the extent and duration of the outbreak. Because of the delayed detection and rapid spread of MRSA type 16, the outbreak grew too large once recognised to be resolved within the available infrastructure. Investments were needed at various fields, including the infection-control service and the microbiology laboratory. Employees had to be informed and motivated, and a separate MRSA ward and OPD were provided. New MRSA outbreaks occurred, despite extensive MRSA (contact) screening among patients and employees. The numbers of isolates began falling as from the beginning of 2003.

Cross Infection↗

Mucositis reduction by selective elimination of oral flora in irradiated cancers of the head and neck: a placebo-controlled double-blind randomized study.

PURPOSE: The aim of the study was to test the hypothesis that aerobic Gram-negative bacteria (AGNB) play a crucial role in the pathogenesis of radiation-induced mucositis; consequently, selective elimination of these bacteria from the oral flora should result in a reduction of the mucositis. METHODS AND MATERIALS: Head-and-neck cancer patients, when scheduled for treatment by external beam radiation therapy (EBRT), were randomized for prophylactic treatment with an oral paste containing either a placebo or a combination of the antibiotics polymyxin E, tobramycin, and amphotericin B (PTA group). Weekly, the objective and subjective mucositis scores and microbiologic counts of the oral flora were noted. The primary study endpoint was the mucositis grade after 3 weeks of EBRT. RESULTS: Seventy-seven patients were evaluable. No statistically significant difference for the objective and subjective mucositis scores was observed between the two study arms (p = 0.33). The percentage of patients with positive cultures of AGNB was significantly reduced in the PTA group (p = 0.01). However, complete eradication of AGNB was not achieved. CONCLUSIONS: Selective elimination of AGNB of the oral flora did not result in a reduction of radiation-induced mucositis and therefore does not support the hypothesis that these bacteria play a crucial role in the pathogenesis of mucositis.

Adult↗

Methicillin-resistant Staphylococcus aureus and Acinetobacter baumannii: an unexpected difference in epidemiologic behavior.

BACKGROUND: The Dutch guideline on hospital policy for the prevention of nosocomial spread of methicillin-resistant Staphylococcus aureus (MRSA) states that patients transferred from hospitals abroad must be placed in strict isolation immediately on admission to a hospital in the Netherlands. Three patients colonized with both MRSA and a multiresistant Acinetobacter were transferred from hospitals in Mediterranean countries to 3 different hospitals in the Netherlands. Despite isolation precautions, Acinetobacter spread in 2 of the 3 hospitals, whereas nosocomial spread of MRSA did not occur. METHODS: For outbreak analysis, the Acinetobacter isolates, identified as Acinetobacter baumannii by the use of amplified ribosomal DNA restriction analysis, were comparatively typed by 4 methods. Comparison of isolation measures in the hospitals was performed retrospectively. RESULTS: In the 2 hospitals in which nosocomial spread of Acinetobacter occurred, most of the epidemiologically related isolates were indistinguishable from the index strains. In these 2 hospitals, isolation measures were in concordance with those recommended for the prevention of contact transmission. The precautions of the hospital in which no outbreak occurred included the prevention of airborne transmission. CONCLUSIONS: Precautions recommended for multiresistant gram-negative organisms are insufficient for the prevention of nosocomial spread of multiresistant Acinetobacter. The airborne mode of spread of acinetobacters should be taken into account, and guidelines should be revised accordingly.

Acinetobacter Infections↗

Investigation of cross contamination in a Mycobacterium tuberculosis laboratory using IS6110 DNA fingerprinting.

SETTING: A laboratory for routine culturing of Mycobacterium tuberculosis. OBJECTIVE: Investigation of an episode of laboratory cross contamination using IS6110 restriction fragment length polymorphism (RFLP) typing. Improvement of laboratory protocols to prevent contaminations in the future. To stress the importance of 'good laboratory practice', and interaction with clinicians about laboratory results. DESIGN: Fingerprinting of mycobacterial isolates from 1) cultures suspected of being contaminated and 2) strains suspected of being the source of the cross-contamination. RESULTS: RFLP typing results indicated that clinical samples were contaminated by strains which had been processed in species identification procedures one day earlier in the same safety cabinet. This cross contamination also resulted in exceptional RFLP typing results--mixed banding patterns. Three patients were treated on the basis of false-positive laboratory results. Because the laboratory results were confusing for the clinicians, the treatment of one true tuberculosis patient was severely delayed. CONCLUSION: 'Good laboratory practice' is very important to prevent cross contamination. RFLP typing proved to be a useful tool to trace the source of contamination. Interaction with clinicians receiving doubtful results is of the utmost importance.

Bacterial Typing Techniques↗

Outbreak of group A streptococci in a burn center: use of pheno- and genotypic procedures for strain tracking.

In a burn center, an outbreak of group A streptococci (GAS) colonizations involving 13 patients and two staff members occurred. Adverse events due to GAS, loss of skin graft after initial take (secondary loss) and partial take, occurred in patients who underwent surgery before the colonization was detected. GAS isolates from nine patients and one staff member were stored and subsequently pheno- and genotyped by T serotyping, gas chromatography, M genotyping, and random amplified polymorphic DNA typing. The outbreak was caused by two types of GAS, identified as T4/28-M48 and T13-M77 by T serotyping and M genotyping. Random amplified polymorphic DNA typing and gas chromatography distinguished both clusters accurately. One subcluster indicated by gas chromatography could be linked to the acquisition of GAS from a roommate. The T13-M77 cluster was characterized by rapid spread through the center compared with the T4/28-M48 cluster. One patient contracted the T13-M77 strain while in protective isolation, indicating a role for staff members in the transmission. Our standard GAS control policy, consisting of twice weekly screening of all burned patients and immediate isolation and treatment, proved efficacious in preventing further spread of GAS. Reporting by staff members of signs and symptoms compatible with GAS infection was reenforced.

Adolescent↗

Safety and efficacy of itraconazole in prevention of fungal infections in neutropenic patients.

In a non-randomized study the efficacy of itraconazole in preventing fungal infections in neutropenic patients was investigated. Forty-seven patients with acute leukemia or advanced lymphoblastic lymphoma were enrolled. Ninety-two episodes of severe neutropenia after chemotherapy were observed. Mean duration of neutropenia was 24 days. Norfloxacin was administered as prophylaxis against gram-negative infections and itraconazole 200 mg b.i.d. as antifungal prophylaxis. Surveillance cultures of throat, urine, feces and vagina or prepuce were performed regularly. Four patients died, two patients due to heart failure, two patients due to staphylococcal pneumonia. Only in one case Candida albicans was cultured from bronchoalveolar lavage fluid. No systemic mycosis or Aspergillus fumigatus pneumonia was documented. In a similar group of patients treated in the preceding 18 months nystatin was used as antifungal prophylaxis. In this group of patients six cases of Aspergillus fumigatus pneumonia, two cases of Candida albicans fungemia and one case of Candida glabrata pneumonia occurred of which six patients died. Itraconazole seems to be effective in preventing fungal infections in neutropenic patients and is well tolerated.

Adolescent↗

Graft-versus-host disease following transplantation of 'one log' versus 'two log' T-lymphocyte-depleted bone marrow from HLA-identical donors.

Prevention of acute graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation, requires the depletion of mature T-lymphocytes from bone marrow grafts. The optimal degree of T-cell reduction is still an open question. We compared two procedures of T-cell separation in 18 consecutive recipients of genotypically HLA-matched bone marrow, who also received cyclosporin A for 6 months. The first method (A) was based on a discontinuous albumin gradient fractionation and resulted in an average T-lymphocyte content of 50 X 10(5)/kg body weight (n = 9 patients); the second method (B) was based on E-rosette sedimentation and reduced the contamination to 15 X 10(4) grafted T-lymphocytes/kg body weight on the average (n = 9 patients). Thus, approximately 90 and 99% of the original T-lymphocytes were removed from the marrow grafts respectively. Of the seven patients of the first group who were at risk of GVHD (excluding two cases of early death), five developed a minimal-to-moderately severe acute GVHD and in two cases chronic GVHD ensued. Lethal GVHD was not seen. Of group B, all recipients engrafted and none developed GVHD (0/9). The difference in the frequency of GVHD between the two groups was highly significant (P less than 0.0025). These data confirm our preclinical studies. They demonstrate that a one-log T-lymphocyte reduction of the marrow inoculum, when combined with cyclosporin A prophylaxis after major histocompatibility complex (MHC)-matched transplantation, is still associated with a considerable incidence of GVHD, whereas a two-log reduction of T-lymphocytes may provide full protection against acute GVHD.

Adolescent↗

Transplantation of non-purified autologous bone marrow in patients with AML in first remission.

Four patients with acute myeloid leukemia (AML) were treated with high-dose cyclophosphamide and total body irradiation followed by reinfusion of a portion of their own bone marrow collected during remission. This procedure was applied when the patients were in complete remission. They did not receive further maintenance chemotherapy after grafting. The use of bone marrow for grafting that had been pre-exposed to high-dose chemotherapy for remission induction did not preclude good hematologic regeneration. All patients showed stable remissions that lasted for 64+, 21, 40+, and 19+ months, respectively. Death in the second patient was due to a medullary relapse of the leukemia. Autologous bone marrow transplantation in patients with AML in remission may permit lasting remissions, even when applied without additional chemotherapy and attempts to purify the marrow of neoplastic cells.

Adolescent↗