Drug susceptibility testing of Mycobacterium tuberculosis complex by use of a high-throughput, reproducible, absolute concentration method.

Accurate drug susceptibility testing (DST) for Mycobacterium tuberculosis is highly important for both therapy guidance and surveillance of drug resistance. Although liquid medium DST methods are used increasingly and seem most efficient and fast, the high costs hamper widespread implementation. In addition, an inability to check the colony morphology of the growing bacteria is a disadvantage of these methods.

A brief history of European harmonization of disinfectant testing - a Dutch view.

Since 1970 we know in Europe that, by engaging in intensive dialog and constructive cooperation it is possible to achieve a generally acceptable test procedure, despite the many divergent approaches taken by the different countries. When in 1966 I began my career as a microbiologist, different procedures were used in all countries to test the efficacy of disinfectants. The results of such tests did not at all lend themselves to comparison.

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.

Nationwide surveillance of drug-resistant tuberculosis in The Netherlands: rates, risk factors and treatment outcome.

Setting: The Netherlands, 1993 and 1994.

Objective: To determine 1) rates of drug resistance in relation to nationality and country of birth, 2) risk factors for drug resistance, 3) treatment outcome of drug-resistant cases, and 4) rates of primary and acquired drug resistance.

Design: Retrospective study of all cases notified with bacillary tuberculosis in The Netherlands in 1993 and 1994.

Molecular epidemiology of infections with Neisseria gonorrhoeae among visitors to a sexually transmitted diseases clinic.

Objectives: To identify determinants for plasmid-mediated resistance to penicillin (penicillinase-producing Neisseria gonorrhoeae [PPNG]) and tetracycline (tetracycline-resistant N. gonorrhoeae [TRNG]) among gonococci, to determine the distribution of bacterial characteristics, and to correlate these with antibiograms and patient characteristics.

Study Design: Gonococcal isolates from 131 patients attending a sexually transmitted diseases clinic in The Netherlands in 1994 were auxotyped and serotyped and antimicrobial susceptibility was tested.

Penicillin-resistant Streptococcus pneumoniae in the Netherlands: results of a 1-year molecular epidemiologic survey.

The molecular epidemiologic characteristics of penicillin-resistant pneumococci in the Netherlands were investigated in 1995. Dutch electronic surveillance data showed that 0.7% of all pneumococci were intermediately resistant and 0.

[Drug resistance in Mycobacterium tuberculosis in The Netherlands].

Objective: To determine magnitude, trend and specific features of the resistance problem.

Design: Descriptive.

Setting: Royal Netherlands Tuberculosis Association, The Hague, the Netherlands.

In vitro susceptibility to antimicrobial drugs of 62 Salmonella strains isolated from horses in The Netherlands.

The in vitro activity of 17 antimicrobial drugs against strains of Salmonella typhimurium (n = 52), Salmonella thompson (n = 2), Salmonella heidelberg (n = 3), Salmonella hadar (n = 2), Salmonella enteritidis (n = 1), Salmonella infantis (n = 1) and Salmonella derby (n = 1) was tested using the agar dilution method. The strains were isolated from horses admitted to the Large Animal Clinics of Utrecht University. The majority of strains were susceptible to gentamicin, amikacin, kanamycin, enrofloxacin, ciprofloxacin, flumequine, colistine, furazolidone and ceftiofur.

Disinfectant testing on surfaces.

During the last decade a consensus view has evolved in Europe on the quantitative testing of disinfectant efficacy in suspension tests, as well as in surface tests. Harmonization of the different national test methods is being pursued within the framework of the European Committee for Standardisation (CEN/TC216). An expert subgroup of the Committee has drafted a test method to measure the microbicidal activity of disinfectants on bacteria attached to surfaces.

[Epidemic of penicillinase-producing, tetracycline-resistant gonococci; risk factors for their spread].

Objective: To assess whether the 1989 epidemic of tetracycline-resistant (TRNG) and penicillinase-producing Neisseria gonorrhoeae (PPNG) was caused by a small number of imported strains, and what the risk factors for infection were.

Design: Retrospective.

Setting: The National Institute of Public Health and Environmental Protection (NIPHEP).

In vitro susceptibility of equine Salmonella strains to trimethoprim and sulfonamide alone or in combination.

The in vitro activity of trimethoprim (TMP) and 9 sulfonamides and their combinations in 6 concentration ratios was tested against 62 Salmonella strains isolated from horses over a 3-year period in the Netherlands, using the agar-dilution method. Most of the isolates were S typhimurium strains (n = 52); the others were S heidelberg (n = 3), S hadar (n = 2), S thompson (n = 2), S enteritidis (n = 1), S infantis (n = 1), and S derby (n = 1). The minimal TMP concentration at which 50% of the Salmonella strains were inhibited (MIC50) was 0.

Establishment of a microbiologically acceptable daily intake of antimicrobial drug residues.

A model is presented to calculate the microbiologically acceptable daily intake (ADIm) of antibiotic residues in food products. The ADIm calculation is based on MIC values for indicator bacteria Escherichia coli, Bacteroides fragilis, Bifidobacterium spp. and Eubacterium spp.

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.

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.

An evaluation of the repeatability and reproducibility of a surface test for the activity of disinfectants.

A collaborative study was carried out to determine the precision of a disinfectant surface test method which is currently under consideration for development as a harmonized European standard surface test. Results indicate that significant variation in microbicidal effect occurs both within and between test laboratories despite careful standardization of test conditions, but that the variability may be less than that associated with suspension tests. Indications are that much of this variability derives from random variations in the resistance of the test strains from day to day and, most particularly, from test period to test period both within as well as between laboratories.

Prevalence of fluoroquinolone resistance in Europe. Study Group 'Bacterial Resistance' of the Paul-Ehrlich-Society for Chemotherapy e. V.

Since 1984, when the first fluoroquinolone, norfloxacin, was marketed in Europe, there has been a marked increase in the usage of this class of drugs. In order to evaluate the influence of this drug usage on the prevalence of resistance to fluoroquinolones in clinical isolates of the family Enterobacteriaceae, Pseudomonas aeruginosa, Staphylococcus aureus, coagulase-negative staphylococci and Enterococcus faecalis we reviewed the susceptibility data from four collaborative surveys conducted between 1983 and 1990 by the Study Group 'Bacterial Resistance' of the Paul-Ehrlich-Society for Chemotherapy. All participating laboratories used the same standardized methods.

In-vitro susceptibility to antimicrobial drugs of bacterial isolates from horses in The Netherlands.

Minimum inhibitory concentrations (MICs) of 30 antimicrobial agents (including the hitherto unreported antimicrobial agents doxycycline, minocycline, vanomycin, 3 quinolones and 3 combinations of antimicrobial agents) for isolates of Salmonella spp. (20), Escherichia coli (17), Klebsiella spp. (8), Proteus spp.

Impaired immune response by isoniazid treatment during intravesical BCG administration in the guinea pig.

At present, isoniazid (INH) is being used prophylactically to reduce the side effects of intravesical BCG therapy for superficial bladder cancer, although it is not clear whether or not this reduces the antitumor efficacy of BCG. In this study the impact of INH treatment on the immune response after repeated intravesical BCG administration was investigated in guinea pigs. INH was given on the 3 days around each BCG instillation.

Monitoring of antibiotic resistance in shigellae isolated in The Netherlands 1984-1989.

During surveillance of antimicrobial resistance in Shigella strains isolated in the Netherlands from 1984 to 1989 and forwarded to the National Institute of Public Health and Environmental Protection for typing, sensitivity to twelve antimicrobial agents was assessed. High rates of resistance to the older drugs of choice in treating shigellosis were found, i.e.

Impaired immune response by isoniazid treatment during intravesical BCG administration in the guinea pig.

At present, isoniazid (INH) is being used prophylactically to reduce the side effects of intravesical BCG therapy for superficial bladder cancer, although it is not clear whether or not this reduces the antitumor efficacy of BCG. In this study the impact of INH treatment on the immune response after repeated intravesical BCG administration was investigated in guinea pigs. INH was given during 3 days starting on the day prior to the BCG administration.

[Mycobacterium avium disease in AIDS patients; diagnosis and therapy].

In eight (25%) of 32 consecutive AIDS patients between 1986 and 1989, Mycobacterium avium infection was diagnosed: in seven disseminated, in one as a local lymph node process. Six patients were treated as consistently as possible with a combination of ethambutol, rifabutine, clofazimine and protionamide (or cycloserine) in relatively large dosages. Median survival of treated patients was 15.