Molecular epidemiology of tuberculosis in the Netherlands: a nationwide study from 1993 through 1997.

To disclose risk factors for active tuberculosis transmission in the Netherlands, restriction fragment length polymorphism (RFLP) patterns of 78% of the Mycobacterium tuberculosis isolates, from the period 1993-1997, were analyzed. Of the respective 4266 cases, 46% were found in clusters of isolates with identical RFLPs, and 35% were attributed to active transmission. The clustering percentage increased strongly with the number of isolates; taking this into account, fewer cases were clustered than has been reported in other studies. Contact investigations in the five largest clusters of 23-47 patients suggested epidemiological linkage between cases. Of patients identified through contact tracing, 91% were clustered. Demographic risk factors for active transmission of tuberculosis included male sex, urban residence, Dutch and Surinamese nationality, and long-term residence in the Netherlands. Human immunodeficiency virus infection was not an independent risk factor for active transmission. Isoniazid-resistant strains were relatively less frequently clustered, suggesting that these generated fewer secondary cases.

Surveillance of antibiotic resistance in Neisseria gonorrhoeae in The Netherlands, 1977-95.

OBJECTIVE: To evaluate the prevalence and epidemiology of penicillinase producing Neisseria gonorrhoeae (PPNG) and tetracycline resistant N gonorrhoeae (TRNG) in the period 1977-95 in the Netherlands. To compare auxotypes, serovars, and antibiograms of PPNG, non-PPNG, and TRNG. To identify determinants in patient characteristics for the epidemic spread of TRNG/PPNG. METHODS: With respect to the national gonococcal surveillance all PPNG isolates from 30 laboratories over the country in 1977-90 and all gonococcal isolates from five sentinel laboratories (during 1 month per quarter) in 1991-5 were collected. Isolates were auxotyped and serotyped, the susceptibility for various antibiotics was tested and plasmid contents were evaluated. Additional data on PPNG infected individuals were collected retrospectively during a microepidemic of TRNG/PPNG. Univariate and multivariate analyses were performed to identify risk factors for TRNG/PPNG infections. RESULTS: In 1995 an overall high prevalence of PPNG infection (27%) and TRNG among PPNG infection (24%) was found in the Netherlands. Importantly, PPNG were found to have higher MICs for ceftriaxone and ciprofloxacin than non-PPNG; clinically relevant resistance to these antibiotics (or related agents) may emerge first among these strains. The observed diversity of strains (123 auxo/serovar classes since 1988) indicates a continuous introduction of new strains into the community. The epidemic increase of TRNG/PPNG was mainly caused by A/S classes NR/1B-6, PRO/1A-3, and PRO/1A-6, suggesting a clonal spread of a few strains; the rapid spread was associated with transmission in high risk individuals (that is, prostitutes and their clients). CONCLUSION: The prevalence of PPNG in the Netherlands remains high and reduced sensitivity to other antimicrobials was detected among the PPNG strains. This underlines the necessity for a continuous national surveillance of resistance in gonococci including limited epidemiological information.

A hospital outbreak of penicillin-resistant pneumococci in The Netherlands.

Respiratory infections with penicillin resistant pneumococci constitute an increasing health care problem. This paper describes the nosocomial spread of penicillin resistant pneumococci (PRP) on a pulmonary ward. During an eight-month period, minimal inhibitory concentrations (MICs) for penicillin and several other antibiotics were performed on all Streptococcus pneumoniae isolates that were shown to be penicillin resistant by a screening assay. The personal data and case history of all patients with penicillin resistant pneumococci were evaluated. Penicillin Resistant Pneumococci were cultured from 18 patients, 16 men (mean age 74 +/- 8 yrs) and 2 women (aged 54 and 60 yrs). Chronic obstructive pulmonary disease was diagnosed in 16 patients, 10 of which had an additional underlying disease (2 diabetes mellitus, 2 heart failure, 2 malignancy). Prior to culture of Penicillin Resistant Pneumococci, 11 out of 18 patients were treated with antibiotics, a beta-lactam in most instances. Ten out of 18 patients died during or shortly after hospitalization. The death of one patient seems to be directly related to infection with Penicillin Resistant Pneumococci. The five Penicillin Resistant Pneumococci isolates available for serotyping were all type 9. The minimal inhibitory concentrations for penicillin varied from 0.5 to 2.0 mg.l-1. High minimal inhibitory concentrations were also noted for cefixime (all over 4.0 mg.l-1) and ceftriaxone (0.5-1.0 mg.l-1). It is concluded that penicillin resistant pneumococci can spread rapidly among old and debilitated patients. Thus, patients with this infection should be barrier nursed.

A multicenter survey of resistance in The Netherlands using the Etest.

To obtain data about the prevalence of resistance in bacterial isolates causing serious infections in the Netherlands, a multicenter survey was carried out using the Etest for quantitative susceptibility testing. More than 6000 isolates belonging to ten species were tested against eight antibiotics. Moreover, the Etest was validated against the agar dilution method and the reproducibility of the Etest was studied. In spite of pH differences between the agar plates used for Etesting and agar dilution testing, a good correlation (that is 86%-97% within log2 dilution steps) was found between both methods. Comparison of Etest values of the participating laboratories and the reference laboratory showed > 80% conformity within 1 log2 dilution step and 90% within 2 log2 dilution steps, indicating a sufficient reproducibility of the Etest. Resistance percentages were low for most species and antibiotics, relatively high percentages (10%-20%) indicating natural insusceptibility rather than development or increase of resistance.