2-Phenethylimidazole derivatives. Synthesis and antimycotic properties.

Compounds of type (X = O, NH; Ar and Ar' = phenyl of substituted phenyl; ten examples) were prepared and assayed against miconazole (II,X = O; Ar = Ar' =2,4-Cl2C6H3) as potential antimycotic agents. Optimal activity was noted for I(X = O; Ar = Ar' = 2,4-Cl2C6H3), the direct analog of miconazole. It is about one-tenth as active.

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.

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. RESULTS: Drug resistance to one or more drugs was reported in 268 (14.6%) of all 1836 cases, of whom 203 (76%) were foreign born. In Dutch patients rates of isoniazid (H) (2.9%) and streptomycin resistance (3.6%) were lower than in foreign patients (8.6% and 10.6% respectively, P < 0.001). Multidrug (H and rifampicin [R]) resistance was reported in 0.5% of Dutch-born and 1.4% of foreign cases (P = 0.055). Rates of acquired resistance to H (11.4%) and HR (5.7%) were higher than rates of primary resistance to these drugs (5.2% and 0.7% respectively, P < 0.05), but the number of retreatment cases was low (6.8% of all cases). Drug resistance was associated with immigration but not with drug use, homelessness or human immunodeficiency virus (HIV) co-infection. One fifth (20%) of drug-resistant cases was diagnosed by active case finding. Treatment outcome in sensitive and resistant cases was compared. CONCLUSION: These findings suggest that drug resistance is imported, but it is unclear to what extent drug resistance among foreigners has been transmitted or created in The Netherlands. Drug resistance data should be monitored in Dutch and foreign patients separately.

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. The outcome of an initial collaborative study from seven laboratories is that this test system yields reproducible results in different laboratories; thus fulfilling the requirements for a basic surface disinfectant test.

Comparative testing of disinfectants against Mycobacterium tuberculosis and Mycobacterium terrae in a quantitative suspension test.

In order to establish a quantitative suspension test to assess the tuberculocidal activity of disinfectants, comparative tests were carried out with a variant of the Dutch Standard Suspension Test using Mycobacterium tuberculosis and Mycobacterium terrae as the test organisms. The results indicate that both species have a similar susceptibility towards disinfectants. Because of this and since M. terrae is a relatively fast growing organism with a low pathogenic potential, it is recommended that this species be used for determining the tuberculocidal potential of new products.

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. However, all strains of Salmonella typhimurium phage type 200 (n = 14), were multiresistant i.e. were resistant to ampicillin amoxycillin, amoxycillin in combination with clavulanic acid, chloramphenicol, nitrofurantoin, trimethoprim, aditoprim and baquiloprim. Two of these strains were also resistant to gentamicin. Based on the susceptibility data found in the present study in combination with pharmacokinetic data available in the literature a rationale for antimicrobial therapy in equine salmonellosis is given. As first choice, gentamicin at a dosage of 3 mg/kg combined with ampicillin at a dosage of 20 mg/kg given with a 8-12 hour dosing interval by intravenous route is advised. As an alternative, the intravenous administration of trimethoprim/sulfonamide combinations given twice daily at a combined dose of 30 mg/kg is suggested.

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. (7), Pseudomonas aeruginosa (7), Actinobacillus equuli (5), Rhodococcus equi (4), Streptococcus zooepidemicus (23), Streptococcus equisimilis (6), Streptococcus equi (4), coagulase-positive Staphylococcus spp. (20) and Taylorella equigenitalis (19) were determined using the agar dilution method. All isolates were of equine origin. MICs were compared with recommended MIC breakpoints. The results indicate that, for some of the pathogenic bacteria evaluated, susceptibility testing of isolates from the individual patient is essential to determine an appropriate antimicrobial treatment.

In vitro susceptibility of some porcine respiratory tract pathogens to aditoprim, trimethoprim, sulfadimethoxine, sulfamethoxazole, and combinations of these agents.

The in vitro antimicrobial activities of aditoprim (AP), a new dihydrofolate reductase (DHFR) inhibitor, trimethoprim (TMP), sulfadimethoxine (SDM), sulfamethoxazole (SMX), and combinations of these drugs against some porcine respiratory tract pathogens were determined by use of an agar dilution method. The minimal inhibitory concentrations (MIC) of these agents were determined twice against Bordetella bronchiseptica (n = 10), Pasteurella multocida (n = 10), and Actinobacillus pleuropneumoniae (n = 20) strains isolated from pigs suffering from atrophic rhinitis or pleuropneumonia. All B bronchiseptica strains were resistant to AP and TMP. The MIC50 values of AP and TMP for P multocida were 0.25 and 0.06 microgram/ml, respectively, and for A pleuropneumoniae, 1 and 0.25 microgram/ml, respectively. The MIC50 values of SDM and SMX for B bronchiseptica were 4 and 1 micrograms/ml, respectively; for P multocida, 16 and 8 micrograms/ml, respectively; and for A pleuropneumoniae, 16 and 8 micrograms/ml, respectively. The investigated combinations of the DHFR inhibitors and the selected sulfonamides had synergism for the A pleuropneumoniae strains; the MIC90 values of the combinations were less than or equal to 0.06 microgram/ml. Potentiation was not observed for the B bronchiseptica and the P multocida isolates. The MIC of the combinations against B bronchiseptica and P multocida corresponded respectively to the concentrations of the sulfonamides and the DHFR inhibitors in the combinations. For A pleuropneumoniae, 2 types of strains were used (25% of serotype 2 and 75% of serotype 9). Type-2 strains had lower susceptibility than type-9 strains to AP and TMP as well as to SDM and SMX (at least a fourfold difference in MIC between the 2 types of strains).(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro antimicrobial activity of sulfonamides against some porcine pathogens.

The minimal inhibitory concentrations (MIC) of sulfonamides were determined against Bordetella bronchiseptica (n = 10), Pasteurella multocida (n = 10), Haemophilus pleuropneumoniae (n = 20), and Streptococcus suis (n = 10) strains isolated from pigs with atrophic rhinitis, pneumonia, or meningitis. Sulfonamides tested in an agar dilution method were sulfachloropyridazine, sulfadiazine, sulfadimethoxine, sulfamethazine, sulfadoxine, sulfisoxazole, sulfamerazine, sulfamethoxazole, sulfamethoxypyridazine, sulfanilamide, sulfatroxazole, and sulfisomidine. Results indicated that monotherapy of S suis infections with sulfonamides should not be encouraged because the MIC50 of all sulfonamides investigated was greater than 32 micrograms/ml. The MIC50 of the sulfonamides against B bronchiseptica ranged from 0.5 to 8 micrograms/ml, against P multocida from 2 to 32 micrograms/ml, and against H pleuropneumoniae from 8 to 64 micrograms/ml. The MIC50 of sulfachloropyridazine, sulfadiazine, sulfadimethoxine, sulfamerazine, and sulfamethoxazole for the gram-negative bacteria did not exceed 16 micrograms/ml. Among these compounds, sulfamethoxazole had the highest activity. The frequently prescribed sulfamethazine had an overall low antimicrobial activity.

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 0.12 micrograms/ml. Sulfachlorpyridazine (SCP; MIC50, 16 micrograms/ml), sulfamethoxazole (SMX; MIC50, 32 micrograms/ml), and sulfadiazine (SDZ; MIC50; 32 micrograms/ml) were the most potent of the sulfonamides tested. The antimicrobial effect of the sulfonamides, in combination with TMP (additive, synergistic, or antagonistic), was expressed by the fractional inhibitory concentration (FIC) index. Concentrations of SDZ and SCP with TMP had marked synergism at all tested TMP-to-sulfonamide concentration ratios (1:1 to 1:160; FIC index, 0.10 to 0.50); SMX had synergy with TMP at all ratios, except 1:1 (FIC index, 0.10 to 0.27). Sulfamethazine, sulfamerazine, sulfadoxine (SDX), sulfatroxazole, sulfadimethoxine, and sulfacetamide had MIC50 greater than their breakpoint MIC value and are, therefore, less potent drugs. However, synergy with TMP was found for these less potent sulfonamides at certain concentration ratios, depending on the sulfonamide used. Sixteen Salmonella strains were resistant to TMP, all sulfonamides, and TMP-sulfonamide combinations; 14 of these strains were S typhimurium phage type 200, 1 was S typhimurium phage type 61, and 1 was S typhimurium phage type 10.(ABSTRACT TRUNCATED AT 250 WORDS)

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., established under gut-like conditions in an in vitro simulation model. The maximum residue level (MRL) for residues in food products can be derived from the ADIm. Four phases can be distinguished in this gastro-intestinal simulation model, namely: 1. In vitro determination of the MIC for each bacterial strain by a standard method. 2. Incorporation of the drug into food (meat, milk) followed by testing of the stability of the antibiotic under gut-like conditions. 3. Adjustment of the 'gastric' fluid to the duodenal situation, inoculation with the test bacteria and anaerobic incubation at 37 degrees C for at least 18 h. 4. MIC reading confirmed by counting bacteria growing on specific solidified media. In this study the method for calculation of ADIm and MRL is given for flumequine as model drug. On the basis of MIC50 values for E. coli strains, a MRL for flumequine of 1.0 microgram/g meat or 0.25 microgram/ml milk was calculated. It is suggested that, depending on the antibacterial spectrum of the antibiotic involved, the ADIm can be determined with selected indicator bacteria, incubated under simulated gastrointestinal conditions.

[Drug resistance in Mycobacterium tuberculosis in The Netherlands]. / Resistentie bij Mycobacterium tuberculosis in Nederland.

OBJECTIVE: To determine magnitude, trend and specific features of the resistance problem. DESIGN: Descriptive. SETTING: Royal Netherlands Tuberculosis Association, The Hague, the Netherlands. METHODS: The data of the National Institute of Public Health and Environmental Protection concerning the prevalence of drug-resistant tuberculosis during the period 1990-1994 were analysed. Also, features of patients with and without drug resistance were compared (Dutch National Tuberculosis Register: cohort 1993). RESULTS: Isoniazid and streptomycin resistance were each observed in approximately 6% of susceptibility tests, showing no clear trend over the study period. Rifampicin resistance increased from 0% to 1.5% in 1994. In the 1993 patient cohort, 809 cases were analysed, showing resistant organisms in 103 (13%). The resistance group included 84 (82%) foreigners versus 387 (55%) among the 'sensitives' (p < 0.001). The percentages of (known) HIV infections were equal in both groups (5-6%). The percentage of isoniazid-resistance varied from 1.8% in Dutch patients to 7.8% in foreign patients. Recent immigrants and refugees waiting for official status were important risk groups for resistance (p < 0.005). Foreign tuberculosis patients defaulted more often from treatment than Dutch patients (p < 0.001). CONCLUSION: Drug-resistant tuberculosis in the Netherlands is mainly due to import of resistant strains. Transmission and further development of resistance within the country must be prevented.

[Mycobacterium avium disease in AIDS patients; diagnosis and therapy]. / Mycobacterium avium-ziekte bij AIDS-patiënten; diagnostiek en therapie.

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 15.5 (4-22) months. Protionamide inhibited most M. avium strains (7 of 8) in vitro, but often caused intolerance (nausea). Treatment of disseminated cytomegalovirus infection in our opinion was necessary in 5 of 6 patients during longterm M. avium therapy. HIV therapy (Zidovudine) during M. avium treatment was not possible due to bone marrow depression. A low maintenance dose of corticosteroids was necessary in 3 of 6 patients (one with adrenal insufficiency) to suppress symptoms such as fever and malaise.

[Epidemic of penicillinase-producing, tetracycline-resistant gonococci; risk factors for their spread]. / Epidemie van penicillinase-vormende en tevens tetracycline-resistente gonokokken; risicofactoren voor de verspreiding.

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). METHOD: A total of 1257 questionnaires were sent to the 5 microbiological laboratories which had contributed most to the number of isolates sent to NIPHEP, in order to obtain additional information of all patients infected in 1989 and 1990 with PPNG. Of all these patients the results of quantitative sensitivity testing, auxotype, serotype and plasmid pattern of the PPNG were obtained. RESULTS: The questionnaire response was 1047/1257 (83.3%). A part of the isolates from the non-responders was included in the study. Determinations were performed in 1185 PPNG isolates (94.3%). In 1988 and 1989 an increase of TRNG among PPNG was observed. The PPNG isolates in 1989 (n - 472) and 1990 (n = 713) from 5 laboratories in Amsterdam. Rotterdam and The Hague, showed that the epidemic was caused mainly by the spread of three strains. NR/IB-6, PRO/IA-3 and PRO/IA-6. The introduction probably took place in The Hague in 1988 and import from abroad could not be confirmed. The TRNG risk was increased for men and women over 40 years and for men from The Hague and Rotterdam having contacts with prostitutes; the latter did not apply to Amsterdam. For women, a Turkish or Latin American nationality increased the TRNG risk. CONCLUSION: Because of the continuing threat of developing resistance and the instability of microbiological characteristics of gonococci, a continuous national surveillance is necessary, including information about risk factors for infection with resistant gonococci, to improve the control of the infection.

[Spread and control of a methicillin-resistant Staphylococcus aureus in an academic hospital]. / Verspreiding en bestrijding van een meticilline-resistente Staphylococcus aureus in een academisch ziekenhuis.

Between December 1988 and March 1989 twelve patients in the Utrecht University Hospital developed an infection with a methicillin-resistant Staphylococcus aureus (MRSA). Twenty other patients and 39 personnel members became colonized with the same MRSA strain. In spite of early isolation measures, progression of this epidemic was probably caused by the extreme degree of contagiousness of the first patient, who had a drug-induced allergic skin eruption. It seems likely that spread occurred via personnel and via a computer tomographic scanner. To contain the epidemic it was necessary to institute a special isolation ward with dedicated personnel. Although several MRSA strains have been introduced in the University Hospital since 1986, the strain we describe here is the only one which spread epidemically.

[Quantitative study of the sensitivity of Bordetella bronchiseptica and Pasteurella multocida to sulfonamides]. / Kwantitatief onderzoek naar de gevoeligheid van Bordetella bronchiseptica en Pasteurella multocida voor sulfonamiden.

Information concerning the resistance to sulfonamides in the Netherlands was obtained by determining the minimal inhibitory concentrations (MIC's) of 119 strains of Bordetella bronchiseptica and 151 strains of Pasteurella multocida, obtained from pigs at five veterinary bacteriology centres, to sulfadimidine (SDM) and sulfamethoxazole (SMX). The MIC's of SDM against Su-susceptible strains were usually 4 times higher than those of SMX. About one third of B. bronchiseptica isolates were resistant (MIC greater than 64 micrograms/ml) to both sulfonamides. Approximately 7% of P. multocida isolates were resistant to SMX, and 21% to SDM. It is concluded that the use of SDM as the sulfonamide of choice for the treatment of atrophic rhinitis is questionable.

[Resistance to antibiotics in Salmonella]. / Resistentie tegen antibiotica bij Salmonella.

Approximately 20,000 strains of Salmonella were screened annually for resistance to tetracycline, chloramphenicol, kanamycin and ampicillin since 1959, and also to trimethoprim since 1978. Tetracycline-resistant strains increased in human subjects and pigs from 1961. After the ban on incorporation of tetracycline in animal feeds for nutritive purposes in 1974, the proportion of tetracycline-resistant strains in pigs and human subjects decreased. In veal calves, the number of strains of S. typhimurium and S. dublin resistant to multiple drugs increased from 1972. Strains resistant to multiple antibiotics in man were mainly isolated from adoptive children from Indonesia. No further spread of these strains was observed. So far, strains similar to those in calves resistant to multiple drugs were only incidentally isolated from human patients.