Acta pathologica, microbiologica, et immunologica Scandinavica. Section B, Microbiology最新文献

Three commercial systems for the identification of non-enteric gram-negative rods were compared with conventional bacteriological methods as reference. The three systems were the API 20 NE, BIO-TEST ID-Trident, and ROSCO Diagnostic Tablets. The systems were tested on a set of 47 strains from the genus Pseudomonas, with the emphasis upon the yellow-pigmented species. The overall identification accuracy was 97% with the API, 19% with the BIOTEST and 68% with the ROSCO system. The API system was thus reliable, and it presented no major practical problems. The BIOTEST system was very handy. The main reason for the low accuracy was an error in the code book. The ONPG reaction was depicted as negative in the species P. paucimobilis. A positive ONPG test is a keymark in this species and 76% of the 20 strains of P. paucimobilis included in this investigation were also found positive with the BIOTEST system. The ROSCO tablets are convenient if the result of single reactions is desired. The time consumption per strain was 5.4, 4.4, and 6.2 min for the API, BIOTEST, and ROSCO systems respectively.

Two Danish agars, Danish Blood Agar (D.B.A.) and Anaerobic Agar (A.A.), were evaluated for their ability to support growth of 47 clinically isolated anaerobic strains in 5 different CO2-concentrations ranging from 0-10% CO2. CO2 and the use of an enriched medium (A.A.) are essential for satisfactory recovery of anaerobes. No gain could be seen when raising the CO2-concentration above 5%. The surface pH of the agars was measured both on non-inoculated and inoculated plates at room temperature and anaerobic incubation in the 5 different CO2-concentrations at 37 degrees C. Temperature change from room temperature to 37 degrees C resulted in a pH decrease of 0.1 units. There was a CO2-mediated decrease in pH (approximately 0.05 units/pr. CO2%) on non-inoculated media. On inoculated plates there was a minor additional fall in pH, which increased with time of incubation, but first became significant when the plates were incubated for more than 24 h. The use of 5% CO2 and A.A. is recommended for antimicrobial susceptibility studies on solid media.

A mucin-degrading microorganism was isolated from the intestinal tract by serial sectioning from the serosal side of the caecum wall from a conventional rat. The ability of degrading the intestinal water-soluble mucin was present both in vivo after monocontamination of germ-free rats and in vitro, when adding the microbe to Mucin medium. The morphology, Gram-positive cocci single or in short chains and the very weak biochemical activities allow us to place this strain in the species Peptostreptococcus micros.

The relative sensitivities of four commercially available kits for the demonstration of the group antigen of group A streptococcus were estimated in laboratory experiments. Two kits gave positive reactions with swabs charged with approximately 10(5) colony-forming units of group A hemolytic streptococci of five common T-types. The two other kits required inocula ten times higher. Application of the antigen detection reagents from each kit to antigen extracts prepared by extraction reagents from the other kits revealed that the differences in sensitivity were largely attributable to differences in the extraction abilities. The four kits did not differ appreciably in their ability to demonstrate group A antigen in human pus mixed with group A streptococci; the minimum inoculum detectable was approximately 10(6) colony-forming units per 0.04 ml of pus.

Sarcocysts belonging to six species of Sarcocystis were isolated from the musculature of reindeer and examined by scanning electron microscopy (SEM) to reveal their surface morphology. Sarcocysts of S. grueneri had thin, strip-like surface processes, cysts of S. rangi had long hair-like processes, and cysts of S. tarandivulpes had short, knob-like processes interconnected by microfolds. Cysts of S. hardangeri had prominent, slanting linguiform processes, whereas the cysts of both S. tarandi and S. rangiferi had upright finger-like surface projections. The processes of S. rangiferi were thicker and longer than those of S. tarandi. SEM of the cysts of these species corroborated and supplemented previous descriptions of their surface morphology, which were based on transmission electron microscopy.

Mouse peritoneal macrophages (MPM) were cultivated with a fibroblast interferon (IFN) preparation or recombinant gamma-IFN (rIFN-alpha) for 1, 24 or 48 h. The zymosan-induced reduction of nitroblue tetrazolium (NBT) in these MPM was then measured. Fibroblast IFN enhanced the NBT reducing capacity of MPM when the incubation period was 1 h. When the incubation period was extended to 48 h, a suppressed NBT reduction by fibroblast IFN treated MPM was recorded. The influence of rIFN-alpha on MPM with regard to NBT reduction was minor. Only when the MPM were treated with a moderate dose of rIFN-alpha (10 U/ml) for 48 h was an enhanced NBT reduction recorded.

Dialysate samples from 29 Continuous Ambulatory Peritoneal Patients (CAPD)-patients were taken in periods with and without peritonitis and cultured simultaneously in the Hemobact system and on conventional plate media, using a standard technique. Bacteria were demonstrated in 23 (92%) of 25 CAPD-patients with peritonitis by the Hemobact method and only in 6 (24%) by the standard technique. Sixty-four (100%) of the 64 samples taken during periods without peritonitis were negative by the standard technique. Sixty-two (97%) of the 64 samples were negative in the Hemobact system. In the remaining two samples coagulase negative staphylococci were demonstrated on the third day in only one of the bottles. In conclusion, blood cultivation systems should be preferred to conventional standard methods for adequate microbiological diagnosis in CAPD-patients with peritonitis.

Decreased susceptibility in vitro to erythromycin has been demonstrated for few C. trachomatis isolates outside Scandinavia, making local susceptibility-screening indicated. Eleven recent isolates of C. trachomatis found in a Danish hospital have been examined for susceptibility, expressed as minimal inhibitory concentration (MIC) to antibacterial agents commonly used in genito-urinary infections. Full susceptibility to doxycycline and erythromycin was demonstrated. Clindamycin and ampicillin showed moderate activity, and sulfamethizole had a MIC value in the border area of what is needed for therapeutic effect in non-urinary infections. C. trachomatis, being a major pathogen in pelvic inflammatory disease, makes combination chemotherapy desirable in order to protect against resistance development, to obtain synergistic effect and to ensure effect in infections of mixed etiology - provided antagonism could not be anticipated. In three checkerboard trials, with the combinations doxycycline plus ampicillin, erythromycin plus sulfamethizole and ampicillin plus sulfamethizole, using MIC as end-point, neither synergism nor antagonism could be demonstrated in the concentration range from 1/8 to 4 times the MIC values of each drug.

Enteric Group 69 has previously only been isolated from beef muscle. Two cases of isolations from human clinical specimens are reported on here: One from a throat swab and one from an abscess. In both cases, only EG 69 was cultured. This group has biochemical reactions similar to Enterobacter cloacae and Enterobacter sakazakii. EG 69 produces yellow pigment as E. sakazakii but only the former ferments sorbitol and dulcitol. EG 69 utilizes malonate and usually ferments sucrose slowly (3-4 days). EG 69 is distinguished from E. Cloacae by production of yellow pigment, fermentation of dulcitol and usually late fermentation of sucrose. EG 69 was found resistant to ampicillin and carbenicillin and susceptible to cephalothin. The pathogenic potential for man is still questionable, but EG 69 is shown to occur in human clinical specimens.