Apmis

ØDum, LARS; Buchanan, THOMAS M.; Knapp, JOAN S.

doi: 10.1111/j.1699-0463.1987.tb03079.xpmid: 3105244

In order to characterize serum‐resistant and serum‐sensitive strains of N. gonorrhoeae, the protein I serotype, auxotype, and penicillin susceptibility of 128 strains were tested. Sensitivity to the complement‐dependent bactericidal activity of normal human serum was highly associated with protein I serotype (p<0.001). Thus 85% of serotype 1–3 strains were serum‐resistant, whereas 86% of serotype 8 strains and all strains with serotypes 8 + 9 or 9 were serum‐sensitive. Serum‐resistance or sensitivity for a given serotype was independent of auxotype. The susceptibility to penicillin within the serotypes 1 – 3 was significantly associated with auxotype (p = 0.0016); all AHU‐ (requirement for arginin, hypoxanthine and uracil) strains had MICs of penicillin of 0.04 μg/ml or less and were serotypes 1 – 3. Among the non‐AHU‐strains, serotype 9 was significantly more penicillin susceptible than the other serotypes (p<0.003).

Gerner‐Smidt, P.

doi: 10.1111/j.1699-0463.1987.tb03080.xpmid: 3565019

328 clinical isolates of Acinetobacter calcoaceticus from hospitalized patients and persons attending general practitioners were characterized according to biotype and resistance‐pattern. 117 strains of biotype (b.) anitratus, 200 of b.lwoffi, 11 of b. haemolyticus and no strains of b. alcaligenes were found. B. anitratus was more frequently isolated from patients in hospitals than b.lwoffi; b.lwoffi was more often found in general practice. Strains of b.anitratus had more resistance traits than b.lwoffi. Strains of b.anitratus obtained in hospitals were more resistant than strains from general practice. No such difference was found with b.lwoffi.

Aalen, REIDUNN B.; Gundersen, WENCHE BLIX

doi: 10.1111/j.1699-0463.1987.tb03081.xpmid: 3031929

The plasmid content of one penicillin sensitive and six penicillin resistant strains of Neisseria gonorrhoeae has been examined. All strains harbour a small, phenotypically cryptic plasmid of 4.1 kilo base pairs (kb). Four of the penicillin resistant strains carry a beta‐lactamase‐producing plasmid of 7.3 kb. One of these also carries a large plasmid of about 40 kb. The two remaining penicillin resistant strains harbour a smaller beta‐lactamase‐producing plasmid of 5.5 kb. The plasmids have been subjected to digestion with a number of restriction endonucleases, and their restriction maps have been compared. Judging by the maps, the cryptic (C‐) plasmids show great similarities. Except that two of them have 54 additional basepairs (bp), and two have a Hpall site instead of a Ddel site, no differences were found. The larger beta‐lactamase‐producing (B‐) plasmids have identical maps. The smaller seem to be homologous with the larger, except for a deletion of 1.8 kb. There is no correlation between the variant of C‐plasmid and type of B‐plasmid harboured in the penicillin resistant strains. The evolutionary implications suggested by this finding are discussed.

Ojeniyi, BENTE; Rosdahl, VIBEKE THAMDRUP; HØIby, NIELS

doi: 10.1111/j.1699-0463.1987.tb03082.xpmid: 3105245

Two Pseudomonas aeruginosa strains, one monoagglutinable and one polyagglutinable, isolated from cystic fibrosis patients were grown in mixed culture. The strains were then separated by means of their azlocillin susceptibility and a number of colonies were tested for serotype and phage type. Changes from monoagglutinable to polyagglutinable reaction and vice versa were observed. The monoagglutinable strain was able to perform bacteriophage infection of the polyagglutinable strain, but no free phages were released. If the donor strain was to produce plaques on the receptor strain, the presence of bacteria belonging to the donor strain was essential.

Digranes, ASBJØRN

doi: 10.1111/j.1699-0463.1987.tb03083.xpmid: 3105246

The in vitro activity of the novel fluoroquinolone derivative, amifloxacin (WIN 49 375), was compared with the activities of ciprofloxacin and ofloxacin. A total of 500 clinical isolates of Gram‐negative and Gram‐positive bacteria were included, and the minimal inhibitory concentration (MIC) was determined by an agar dilution method. All drugs were highly active against Enterobacteriaceae, but ciprofloxacin showed the highest activity on a weight‐for‐weight basis (MIC 90%≤ 0.03 mg/l). Ciprofloxacin was the most active agent against Pseudomonas isolates; all isolates being inhibited by 0.25 mg/l or less. The staphylococcal isolates were inhibited by ciprofloxacin and ofloxacin at relatively low concentrations (MIC 100%= 1 mg/l), whereas amifloxacin showed moderate activity against the majority of these isolates. Ciprofloxacin was highly active against enterococci, ofloxacin was moderately active, and amifloxacin was inactive. All Neisseria gonorrhoeae isolates were susceptible to the lowest concentrations of the agents that were employed in the study (0.03 mg/l).

Ursing, JAN; Bruun, BRITA

doi: 10.1111/j.1699-0463.1987.tb03084.xpmid: 3565016

DNA‐DNA reassociation studies on 52 strains of Flavobacterium meningosepticum showed two main hybridization groups about 40–55% interrelated and comprising 4 and 48 strains respectively. The larger group could be further divided into four subgroups if differences in thermal stability of the reassociated duplexes were taken into consideration. Of a total of 20 strains isolated from cerebrospinal fluid, 18 were found in one subgroup of 28 strains, which also contained seven blood isolates. The results indicate that genetically defined subgroups within the species might differ with regard to pathogenic significance.

Bruun, BRITA; Ursing, JAN

doi: 10.1111/j.1699-0463.1987.tb03085.xpmid: 3565017

Fifty‐two strains found to belong to Flavobacterium meningosepticum on the basis of DNA‐DNA hybridization analyses were characterized and found to be phenotypically homogeneous. All strains were oxidase, catalase, indole, gelatinase and beta‐galactosidase positive, and produced acid from glucose, mannose, fructose, maltose and mannitol; nitrate was not reduced. F. meningosepticum could be differentiated from Flavobacterium group IIb by its ability to produce beta‐galactosidase, and by the latter taxon's ability to produce a bright yellow pigment in contrast to the weak or non‐existing pigmentation of F. meningosepticum. Phenotypic characteristics that could differentiate between the two main DNA relatedness groups of F. meningosepticum were not discovered, wherefore a subdivision of the present species into two species cannot be recommended. Strains from the DNA relatedness groups comprising 19 of 20 CSF isolates were found to be able to grow at 40°C and to produce a weak yellow pigment; in contrast, strains from the three other DNA relatedness groups were unable to grow at 40°C and produced no pigment.

Westergaard, J.; Fiehn, N.‐E.

doi: 10.1111/j.1699-0463.1987.tb03086.xpmid: 3565018

The purpose of this study was to elucidate the distribution of spirochetes (SP), on the basis of ultrastructural criteria in subgingival plaque from patients with advanced marginal periodontitis. Samples were obtained by a paperpoint technique from 18 pockets 6–10 mm in depth from 12 individuals. On grids with negatively stained material, more than 50 SP were photographed from each sample. The SP were primarily grouped according to the number of endoflagella from each cell‐end, with the exception of SP with more than eight endoflagella, which were pooled in one group. The diameter, the length, the wavelength and the amplitude of the SP were measured and related to the number of the endoflagella. The 95 per cent and 99 per cent confidence intervals were estimated. Owing to the number of endoflagella, the distribution of SP varied in the separate samples and no relationship to pocket depth was found. SP containing two endoflagella were the pre‐dominating type. On the basis of the dimensions of the diameter, the length, the wavelength and the amplitude, the SP fell into four significantly different morphological groups characterized by 1, 2, 3–8, and more than 8 endoflagella, as the values in general increased from group to group.

Kristiansen, KARINA; Baloda, SURAJ B.; Larsen, JENS L.; WadstrÖM, TORKEL

doi: 10.1111/j.1699-0463.1987.tb03087.xpmid: 2882644

Fifty Salmonella dublin strains isolated from cattle and human diarrhoeal cases were assayed for toxin production, haemagglutination, cell‐surface hydrophobicity and fibronectin‐binding properties. Most strains (65% of tested) produced cytotonic toxins and cytotoxic factors when tested on Chinese hamster ovary (CHO) cells and rabbit skin test. However, only three strains produced a skin‐permeability factor as determined in pig skin intra‐dermal tests. None of the strains were positive in pig intestinal loop tests. Six of the 32 strains tested for 125I‐fibronectin and its 125I‐29 kDa N‐terminal domain binding showed 10–17% and 6–10% binding, respectively. Most of the strains expressed mannose‐sensitive haemagglutination (MSHA) (76%) and high cell‐surface hydrophobicity (74%) when grown at 37 °C. At 20 °C the expression of MSHA and especially the expression of high cell‐surface hydrophobicity were reduced. Twelve strains grown at 37 °C did not haemagglutinate erythrocytes from five animal species used in this study, while six of these strains expressed high cell‐surface hydrophobicity. Salmonella dublin strains isolated in Denmark appeared to express a higher frequency of fimbriae type 1 (MSHA) and a lower frequency of high cell‐surface hydrophobicity than the strains from external sources.

Jansen, JENS E.; Bremmelgaard, ANNIE

doi: 10.1111/j.1699-0463.1987.tb03088.xpmid: 3105247

Anaerobic agar (AA) and Danish Blood agar (DBA) were evaluated by a standardized agar diffusion and agar dilution test in 5% CO2. The activity of seven antibiotics (tetracycline, clindamycin, metronidazole, rifamycin, chloramphenicol, penicillin, erythromycin) was tested against 40 anaerobic bacteria, including 3 control strains (Cl.perfringens ATCC 13124, B.fragilis ATCC 25285, B.thetaiotaomicon ATCC 29741). 70% of the strains were resistant to erythromycin in 10% CO2, only 30% in 5% CO2. No evident CO2‐effect could be seen with the other antibiotics. Mean MIC for tetracycline was twice as great on AA than DBA. In spite of that, tablet sensitivity testing with tetracyline on AA proved to be more accurate and completely separated the resistant and susceptible strains. For penicillin, the mean MIC was one dilution step higher on AA. No major differences could be seen with the other antibiotics. AA was superior to DBA in providing growth of anaerobes. Measurement on AA was easier, and it was more precise. Except for tetracycline, MIC on control strains fell well within range set by The National Committee for Clinical Laboratory Standards (NCCLS) on AA. Acceptable correlation coefficients were recorded between agar diffusion and agar dilution. Prediction of susceptibility based on zone diameter measurements was very good on AA. Only one discrepancy that could cause change of susceptibility status occurred on AA, while there were 12 on DBA. On DBA, there was poor correlation between MIC, compared with earlier results on the same agar. The 50% inhibitory concentration (IC50) was also measured, but offered no advantage over MIC.