Zentralblatt fur Bakteriologie. 1. Abt. Originale. A: Medizinische Mikrobiologie, Infektionskrankheiten und Parasitologie最新文献

The hazards of acquiring a nosocomial infection are significant even in modern hospitals in spite of aseptic procedures and antibiotics. In order to prevent or stop a hospital epidemic it is necessary to know or to recognize the infective agent, its source and its way of spreading. This is not always easy, esp. with some potential pathogens which are frequently found in the pathological materials as well as in the hospital environment. In the described series of hospital spread of Alcaligenes odorans, var. viridans, it was not difficult to identify the bacterium, it was easy to state the source and not very hard to eradicate it. The way of spreading, however, remained unclear. Hospital infections occur everywhere, even if sometimes unrecognized. With modern treatments facultatively pathogenic bacteria are increasingly becoming hospital infectants. Our aim was to look for such ones, esp. if not described yet as hospital infections.

During a period of 16 months 1757 strains of nonfermentative gram-negative rods have been isolated from clinical material. Of the, 1205 (69%) were P. aeruginosa, 124 (10%) of which failed to produce pyocyanin. The apyocyaninogenic strains as well as the remaining 552 isolates were differentiated by steps according to a diagnostic scheme developed by us. For identification of species two or three steps were needed. By this procedure, 530 of the 552 strains could be assigned to nineteen species within the genera Pseudomonas, Achromobacter, Alcaligenes, Flavobacterium, Agrobacterium and Acinetobacter. 17 strains could not be identified below the genus level, one strain belonged to CDC-group VE-2 and four strains were not identifiable. 72% of the 552 strains belonged to only four species: Pseudomonas putida, P. maltophilia, Acinetobacter lwoffii and A. anitratus.

Piglets which were early-weaned at the age of 21.7 days and experimentally monoinfected with oocysts of Isospora suis showed distinct reductions in zootechnical criteria during an experimental period of 4 weeks. The daily liveweight gains in the infected piglets (group B) was 19.7% lower than in the control group A, which was free of Coccidia. Comparative photographs with the REM showed serious lesions in the small intestine of infected piglets, which are thought to be mainly responsible for the reduced productivity. The application of 150 mg Lasalocid per kg of total feed to infected piglets caused the rate of weight gain to attain the same values as the noninfected controls (group A). Piglets receiving Lasalocid treatment passed oocysts with the faeces which were infectious. On the other hand, infected piglets which were treated with 6 mg Halofuginone per kg of total feed did not contain any oocysts in the faeces. Despite having a higher liveweight at the beginning of the experiment, this group only gained as much liveweight as the infected piglets (group B). This depression in liveweight gains could be explained by the significantly reduced uptake of feed, which was 21.1% lower than in the controls (group A). 6 weeks after the first infection, a re-infection resulted in the appearance of oocysts in the faeces of the piglets which had been treated with Halofuginone. On the other hand, the animals treated with Lasalocid had developed an efficient immunity to Isospora suis.

Two strains of Streptococcus pyogenes, originating from the same Griffith strain SF 130/13 but different in M protein synthesis, produce two isostreptokinases. The molecular weights of both isostreptokinases are the same (about 50 000 daltons) as well as the specific activities (38 000 and 43 000 U/mg, resp.). The activity values are influenced by an incomplete removal of ampholytes. The isoelectric points were determined as pI 6.3, and 6.5, resp. The presence of isostreptokinases was concluded by (1) the absence of proteolytic activities in the culture filtrate, (2) the same molecular weights, (3) the same specific activities, (4) the constant quantitative relation of about 1:2.5 between both isostreptokinases after refocusing, (5) a lack of cystein- or cystin residues in the molecule, (6) the appearance of both isostreptokinases in untreated culture filtrates, (7) the separability by disc electrophoresis, and (8) the lack of such double bands in streptokinases of other streptococci. Isoelectric focusing of streptokinase produced by a type 3 strain of S. pyogenes was followed by the appearance of four bands with streptokinase activity. It is unlikely that these four bands represent isostreptokinases. Both streptokinases (type 1 and type 3 streptococci) differ from streptokinases of other types by their relatively high content of tryptophane (table 1) and the high isoelectric points (6.5 to 6.0; streptokinases of other types and groups show pI's between 5.05 to 5.65 (6).

The phylogenetic relationships among strains of Pasteurella multocida representing Carter's serogroups A, B, (C), D and E, the type strain (which also represents serogroup A, and biovar 4), the indole-negative strain Schütze HS, and two "dog-type" strains (biovar 6) were investigated by DNA:DNA hybridization using the optical method. The genome DNAs of the "dog-type" strains were almost identical; they displayed, however, only 20% binding with the DNA of the type strain of P. multocida, and even lower or no measurable binding with the DNAs of the other strains tested. The taxon hitherto classified as biovar 6 of P. multocida is therefore considered as a distinct species; yet the data so far available do not rule out that it belongs to a genus other than Pasteurella sensu stricto. - The remaining strains exhibited high genome DNA relatedness, with between 64 and 98% DNA binding. The present data do not rule out the existence of molecular subspecies in P. multocida.

81 strains of Staphylococcus aureus (41 methicillin-resistant and 40 -sensitive ones) were tested against older and newer cephalosporines in both broth-dilution and agardiffusion-tests using Mueller-Hinton (MH)-broth and MH-agar respectively in order to establish the degree of parallel-resistance. The substances used were cephalothin, cefazolin, cephalexin, cefamandol, cefuroxim, cefoxitin, cefotaxim and cefsulodin. Furthermore, for reasons of comparison the relatively new substance "Oxabetalaktam" was included in the investigation. As shown in Fig. 1 and Table 1 all methicillin-resistant strains required at the average at least 10 times the concentrations of cephalosporine (excepting cefsulodin) which was necessary to inhibit methicillin-sensitive strains. Again excepting cefsulodin, for each cephalosporine there was a clear bimodal distribution indicating a clear separation of both populations of strains: methicillin-sensitive and -resistant ones. Cephalothin cannot be used as test substance in agardiffusion-tests with staphylococci as there is no correlation between MIC and the inhibition zone size (Fig. 2). This is not necessary, anyway, since all methicillin-resistant strains must be regarded as resistant against virtually all cephalosporines available on the market (with the possible exception of cefamandol). By contrast, all methicillin-sensitive strains may be attacked successfully by concentrations of cephalosporines that are thought to be also effective in vivo. Since in agardiffusion-tests methicillin-resistant strains of staphylococcus aureus are recognizable as easily as are otherwise merely penicillinase-producing ones (5) by using a paper disk loaded with 6 microgram benzyl-penicillin and since infections due to other grampositive organisms than staphylococci are no indication for treatment with cephalosporines there is no need to test any other betalactam-antibiotic than benzyl-penicillin with gram-positive organisms.

Chlamydial particles and soluble hemagglutinin were separated by differential centrifugation from the supernatant of L-cells and the allantoic fluid of chick embryo infected with C. psittaci 6BC and C. trachomatis TW-3. Concentrated hemagglutinin was fractionated with ether-ethanol; specimens were compared using sensitive erythrocytes of adult white Leghorn chickens. The ether-ethanol extract had a 40- to 80-fold higher hemagglutinin titer than the crude hemagglutinin or the ether-ethanol insoluble fraction. The extracted hemagglutinin also showed a higher complement-fixing activity than the other two fractions. Extracted hemagglutinin was stable for 3 months at 4 degrees and --70 degrees C when sonicated immediately before hemagglutinin; it agglutinated to a similar titer at 37 degrees, 25 degrees and 4 degrees C, showing the reaction to be temperature independent; it agglutinated to a similar titer within a pH range of 7.0 to 8.0 McIlvaine citrate buffer-saline solution and Dulbecco's phosphate buffer solution without Ca++ and Mg++ at pH 7.0 were both suitable for hemagglutinin-titration. Hemagglutination failed to take place in non-electrolyte solutions.

Investigations are reported which attempt to contribute towards an understanding of those cases in which topical treatment with erythromycin is unsuccessful. In 13 acne patients no resistance of P. acnes was observed after seven weeks of topical treatment with erythromycin. This demonstrates that the 20% frequency of resistance induction reported in the literature is too high. In the 13 treated patients there was no essential reduction in the number of inflammatory lesions although a decrease in the number of Propionibacteria in the pilosebaceous ducts occurred. This result is perhaps connected with a concurrent increase in Micrococcaceae, which could suggest that not only Propionibacteria, but also Micrococcaceae play a role in the pathogenesis of acne.

To enable studies of the dependence of Cryptococcus neoformans and its perfect and imperfect states upon bird manure as a habitat of this pathogen, a nutrient medium closely resembling natural conditions was prepared. As sole nutrient, the water soluble ingredients of manure from pigeons (Columbia livia) were used. There was no heat sterilization of the manure filtrate. Using a standard pair of C. neoformans strains for mating, it could be demonstrated that the perfect state of the fungus developed on this so called pigeon manure filtrate agar within 48 h at 26 degrees C. This medium is supposed to help in the elucidation of the epidemiological significance of the perfect and imperfect states of this pathogen.

Lysogenicity with phages of serogroup B is a prerequisite to the transfer of drug resistance plasmids in mixed cultures of Staphylococcus aureus. This is demonstrated by experiments with transfer of the plasmids pII 147, pC 221, pT 127, pE 2222 to strain 8325-4 which was lysogenized for different phages of different serogroups (Table 2). The transfer is also possible, when the donor strain or the recipient strain are lysogenic for the phage mutant phi 11, M 28, which is able to lyse strain 8325-4 but unable to form phage heads (Kretschmer and Egan, 1975). The fact that the induction of prophage phi 11 and steps of phage-propagation are necessary for the transfer, is evident from negative results obtained by use of the rec--mutant of strain 8325 (RN 981) as donor and by use of strain 8325-4 lysogenic for the phage mutant phi 11, A 4 as donor. The phage mutant phi 11, A 4 is defective at an early step of phage propagation. These experiments are shown in Tables 3 and 4. The possibility of transfer using donor or recipient strains which are lysogenic for a phage-mutant but unable to form phage heads clearly shows that the transfer is not based on transduction. Incubation of non lysogenic donor and recipient cells in the culture supernatant of strain 8325-4 (phi 11, M 28) or in the lysate of strain 8325-4 obtained after infection with phage phi 11, M 28 also allows the transfer of plasmids. Obviously one of the components of serogroup B phages is essential for the transfer.