A.J.L. Weersink

Quantitation of surface CD14 on human monocytes and neutrophils.

The absolute number of membrane‐expressed CD14, the most important endotoxin receptor, on human monocytes and neutrophils shows remarkable variation in the literature. To quantify these numbers two fluorescence methods using fluorescein isothiocyanate (FITC)‐labeled monoclonal antibodies (mAb) were applied. A commercially available set of standard beads was used in flow cytometry to quantitate CD14 with eight different mAbs. Independent from their isotype the various mAbs showed minor differences and indicated that peripheral blood monocytes expressed 99,500–134,600 (115,400 ± 10,600) and neutrophils 1,900–4,400 (3,300 ± 800) CD14 receptors. There was no significant difference in CD14 expression on leukocytes in unprocessed freshly obtained whole blood and after a Ficoll isolation procedure. However, a short temperature shift resulted in a 1.3‐ to 1.6‐fold upregulation of CD14. The results obtained with the reference beads were verified with fluorescence Scatchard analysis and spectrofluorometry using mAb 26ic‐FITC and showed 109,500 CD14 per monocyte and 6,700 CD14 per neutrophil. For comparison the number of CD14 on the monocytic THP‐1 cells and Fcγ‐receptors on human leukocytes were determined using the reference beads and flow cytometry and gave results comparable to published data. Our data indicate that resting human monocytes express roughly 110,000 CD14 molecules on their surface using a simple fluorometric assay. Correct determination of the number of CD14 and other cell surface receptors is of importance in the monitoring of septic patients. J. Leukoc. Biol. 61: 721–728; 1997.

Role of healthcare workers in outbreaks of methicillin-resistant Staphylococcus aureus: a 10-year evaluation from a Dutch university hospital.

BACKGROUND AND OBJECTIVE The benefit of screening healthcare workers (HCWs) at risk for methicillin-resistant Staphylococcus aureus (MRSA) carriage and furloughing MRSA-positive HCWs to prevent spread to patients is controversial. We evaluated our MRSA program for HCWs between 1992 and 2002. SETTING A university medical center in The Netherlands, where methicillin resistance has been kept below 0.5% of all nosocomial S. aureus infections using active surveillance cultures and isolation of colonized patients. DESIGN HCWs caring for MRSA-positive patients or patients in foreign hospitals were screened for MRSA. MRSA-positive HCWs had additional cultures, temporary exclusion from patient-related work, assessment of risk factors for persisting carriage, decolonization therapy with mupirocin intranasally and chlorhexidine baths for skin and hair, and follow-up cultures. RESULTS Fifty-nine HCWs were colonized with MRSA. Seven of 840 screened employees contracted MRSA in foreign hospitals; 36 acquired MRSA after contact with MRSA-positive patients despite isolation precautions (attack rate per outbreak varied from less than 1% to 15%). Our hospital experienced 17 MRSA outbreaks, including 13 episodes in which HCWs were involved. HCWs were index cases of at least 4 outbreaks. In 8 outbreaks, HCWs acquired MRSA after caring for MRSA-positive patients despite isolation precautions. CONCLUSION Postexposure screening of HCWs allowed early detection of MRSA carriage and prevention of subsequent transmission to patients. Where the MRSA prevalence is higher, the role of HCWs may be greater. In such settings, an adapted version of our program could help prevent dissemination.

Surveillance of nosocomial infections in geriatric patients

Prospective surveillance of hospital-acquired infections was undertaken in the geriatric ward of the University Hospital, Utrecht, the Netherlands. The medical records of 300 patients were studied for the presence of nosocomial infections using the criteria defined by the Centers for Disease Control (CDC), Atlanta, Georgia, USA. Data were collected from patients with and without infection, which allowed for the analysis of risk factors for nosocomial infection. In 100 out of 300 patients (33.3%), a total of 126 infections was diagnosed. The incidence of nosocomial infections was 16.9 per 1000 days of stay in the hospital. The mean length of stay of patients with infection was 39 days, while that of patients without infection was 17.8 days. Infections developed after an average stay of 13.3 days in the hospital. Patients with infections were 2.6 years older than patients without infections (P = 0.005). Dehydration was shown to be a major risk factor for infection (RR = 2.1, 95% CI: 1.4-3.2). Of the infections, 58.7% were urinary tract infections (UTIs, asymptomatic and symptomatic). The most important risk factor for an asymptomatic UTI was an indwelling urinary catheter (RR = 7.3, 95% CI: 3.1-17.1). The duration of use of the indwelling urinary catheter was of significant influence in the development of a UTI. Seventy percent of the patients with an asymptomatic UTI were treated with antibiotics. Infections of the gastrointestinal tract accounted for 19.8% of all nosocomial infections. The majority of these infections were due to an outbreak of Clostridium difficile. In conclusion, the length of stay may be prolonged by a nosocomial infection. In this study, the main risk factors for developing a nosocomial infection were age, dehydration and the presence of an urinary catheter. Our observations showed that age is a predisposing factor for nosocomial infection and that the risk increases with each year, even for geriatric patients.

Surveillance for hospital-acquired infections on surgical wards in a Dutch university hospital

OBJECTIVES To determine incidence rates of hospital-acquired infections and to develop preventive measures to reduce the risk of hospital-acquired infections. METHODS Prospective surveillance for hospital-acquired infections was performed during a 5-year period in the wards housing general and vascular, thoracic, orthopedic, and general gynecologic and gynecologic-oncologic surgery of the University Medical Center Utrecht, the Netherlands. Data were collected from patients with and without infections, using criteria of the Centers for Disease Control and Prevention. RESULTS The infection control team recorded 648 hospital-acquired infections affecting 550 (14%) of 3,845 patients. The incidence density was 17.8 per 1,000 patient-days. Patients with hospital-acquired infections were hospitalized for 19.8 days versus 7.7 days for patients without hospital-acquired infections. Prolongation of stay among patients with hospital-acquired infections may have resulted in 664 fewer admissions due to unavailable beds. Different specialties were associated with different infection rates at different sites, requiring a tailor-made approach. Interventions were recommended for respiratory tract infections in the thoracic surgery ward and for surgical-site infections in the orthopedic and gynecologic surgery wards. CONCLUSIONS Surveillance in four surgical wards showed that each had its own prominent infection, risk factors, and indications for specific recommendations. Because prospective surveillance requires extensive resources, we considered a modified approach based on a half-yearly point-prevalence survey of hospital-acquired infections in all wards of our hospital. Such surveillance can be extended with procedure-specific prospective surveillance when indicated.

A pilot study on infection control in 10 randomly selected European hospitals : Results of a questionnaire survey

We describe and compare the organization of infection control and some infection control practices in 10 hospitals in seven different European countries. Great differences were observed. By evaluating infection control and hygiene practices in different European centers, areas of prime importance for the development of a European infection control standard may be defined.

Coxiella burnetii infection, a potential cause of neuroretinitis-two case reports and literature review.

Neuroretinitis is an (sub)acute inflammatory process affecting the optic nerve, which may result in permanent visual loss. Clinical characteristics include an afferent pupillary defect, optic nerve head swelling, and macular star exudates. The causes of neuroretinitis remain frequently undetermined, but the associations with infections have been regularly reported, including syphilis, borreliosis, bartonellosis, toxoplasmosis, tuberculosis, leptospirosis, and diverse viral infections.1 To our knowledge, only two cases of neuroretinitis have been attributed to infections due to Coxiella.2,3 In this report, we describe two patients with neuroretinitis and systemic Coxiella burnetii infection.

Infectious Uveitis in Thailand: Serologic Analyses and Clinical Features

Purpose: To determine the seroprevalence of various infectious agents in Thai patients with uveitis. Methods: Prospective study of 101 consecutive patients with uveitis, 100 HIV-infected retinitis patients, and 100 nonuveitis controls. Results: Antibodies against T. gondii were detected in 31/101 non-HIV patients, mostly with posterior uveitis and focal retinitis, and were significantly higher than in other groups examined. Antibodies for T. pallidum and Leptospira were observed more frequently in patients with HIV-infected retinitis. Active tuberculosis in non-HIV patients was not found. Conclusions: Seroprevalence of T. gondii antibodies in patients with non-HIV posterior uveitis was higher than in nonuveitis controls and HIV patients with retinitis.