Zentralblatt für Bakteriologie, Mikrobiologie und Hygiene. Series A: Medical Microbiology, Infectious Diseases, Virology, Parasitology最新文献

MICs of ciprofloxacin (CIP), ofloxacin (OFL) and norfloxacin (NOR) were assessed with a total of 523 strains of 7 species (spp) of enterobacteriaceae, various pseudomonads, methicillin-susceptible and -resistant S. aureus, L. monocytogenes, Legionella species and C. difficile. In addition, the MBCs were assessed with S. aureus and E. coli. With break-points of ≤ 0,5 and ≥ 4 mg/l all strains of E. coli, K. oxytoca, P. mirabilis and indole-positive Proteus spp. were susceptible to all 3 antibiotics. Proportions of susceptible strains almost as high were found with E. cloacae, S. marcescens, K. pneumoniae and methicillin-susceptible staphylococci. With Legionella spp. the MICs of CIP and OFL always indicated susceptibility, whereas with NOR only 62% of the strains were inhibited. Pseudomonads, especially others than P. aeruginosa, were only moderately susceptible to CIP and OFL, but never to NOR. Listeria monocytogenes was susceptible to OFL in 96%, to CIP in 56%, but never to NOR. C. difficile was always resistant. The MBC-values either equalled the MICs or surpassed them up to 2 times at maximum indicating a bactericidal mode of action. Despite of slightly lower MICs of CIP in vitro, OFL seems to be comparably effective. NOR is regarded less effective.

Die MHK-Werte von Ciprofloxacin (CIP), Ofloxacin (OFL) und Norfloxacin (NOR) wurden an insgesamt 523 Stämmen von 7 Enterbacteriaceae-Specks, verschiedenen Pseudomonaden, Methicillin-emphndlichen und -resistenten Stämmen von S. aureus, L. monocytogenes, Legionella spp. und C. difficile bestimmt. Bei S. aureus und E. coli wurde zusätzlich die MBK ermittelt. Bei Annahme der Grenzkonzentrationen (mg/1) von ≤ 0,5 und ≥ 4 waren alle Stämme von E. coli, K. oxytoca, P. mirabilis und die der indolpositiven Proteus spp. gegenüber allen drei Antibiotika empfindlich. Ein jeweils fast ebenso hoher Anteil empfindlicher Stämme fand sich bei E. cloacae, S. marcescens, K. pneumoniae und den Methicillin-empfindlichen Staphylokokken. Die bei Legionella spp. gemessenen MHK-Werte von CIP und OFL zeigten immer „empfindlich“ an, wogegen dies bei NOR nur für 62% der Stämme zutraf. Pseudomonas-Arten, vor allem andere als P. aeruginosa, waren gegen CIP und OFL häufig mäßig oder, wie gegen NOR, überhaupt nicht empfindlich. Listeria monocytogenes war meistens empfindlich gegen OFL, bei etwa der Hälfte der Stämme gegen CIP, nicht aber gegen NOR. C. difficile war immer resistent. Die an S. aureus und E. coli gemessenen MBK-Werte lagen bis höchstens 2 Stufen über denen der jeweiligen MHK. Trotz der im Durchschnitt etwas niedrigeren MHK-Werte von CIP scheint OFL in vitro vergleichbar häufig wirksam zu sein. NOR ist vielfach als weniger wirksam einzustufen.

The antibacterial activity of 33 substituted and unsubstituted seven-member ring tropones and tropolones was examined on 14 reference strains representing Gram-positive and Gram-negative bacteria. It was shown that the chemical character and position of the substituent plays a distinct role in the biological activity of investigated compounds. Depending on the substituent the antibacterial effect may be either increased or diminished. C-1 thio and C-2 nitro derivatives of tropone are significantly more active than tropone. The dibenzotropone derivatives display no antibacterial activity. Hydroxymethyl derivatives of tropolone are more active than tropolone, while hydroxy-, isopropyl-, methyl- as well as tropolone acetates are equipotent.

Von 33 substituierten und nichtsubstituierten 7-Ring-Tropon- und -Tropolon-Verbindungen wurde deren antibakterielle Aktivität untersucht, getestet mit 14 grampositiven und gramnegativen Referenzstämmen. Die chemische Struktur und die Position der angelagerten Gruppe entscheiden über die antibakterielle Aktivität der entsprechenden Verbindung. Die antibakterielle Aktivität kann hierbei erhöht oder erniedrigt werden, so sind C-l-Thio- und C-2-Nitroverbindungen des Tropons signifikant aktiver als das Tropon selbst. Dibenzotropon-Verbindungen zeigen keine antibakterielle Aktivität. Hydroxymethyl-Verbindungen des Tropolons sind wirksamer als Tropolon selbst, während Hydroxy-, Isopropyl-, Methyl-und Azetat-Verbindungen des Tropolons sich als gleichwertig erwiesen.

Immunostimulating and antineoplastic activities of staphylococcal lipoteichoic acid (LTA) were studied in Balb/c-mice. Systemic administration of LTA (1 mg or 2 mg i.p., 7 and 4 days prior to challenge) significantly enhanced chemiluminescence response of peritoneal macrophages (p < 0.0125) and induced enlargement of the spleen (p < 0.025) as compared to non-treated controls. In vivo the number of lung colonies was significantly lower (p < 0.0125) in LTA-treated mice 14 days after challenge with L-1 sarcoma cells.

A total of 734 strains of gram-negative nonfermentative bacteria (46 species and biochemically defined groups) of the genera Pseudomonas, Alcaligenes, Bordetella, Moraxella, Acinetobacter, Agrobacterium, and Flavobacteriwn were investigated for their ability to hydrolyze 25 different chromogenic substrates. All tests were carried out in growth-stimulating media. Results were read photometrically and evaluated automatically following a 24-h incubation. Many of the 46 different species and biochemical groups exhibited uniform patterns of enzyme production. Some of the enzyme tests may serve as additional valuable tools for differential diagnosis of the organisms investigated. In combination with other biochemical tests, qualitative enzyme demonstration tests can facilitate the identification of gram-negative nonfermentative bacteria.

Insgesamt 734 Stämme gramnegativer nicht-fermentativer Bakterien aus 46 verschiedenen Species oder biochemisch definierten Gruppen der Gattungen Pseudomonas, Alcaligenes, Bordetella, Moraxella, Acinetobacter, Agrobacterium und Flavobacterium wurden hinsichtlich ihrer Fähigkeit zur Hydrolyse 25 verschiedener chromogener Substanzen untersucht. Alle Tests wurden in einem wachstumsförderdem Medium durchgeführt. Die Testresultate wurden photometrisch erfaßt und nach einer Inkubationszeit von 24 h automatisiert ausgewertet. Viele der 46 unterschiedlichen Spezies zeigten ein einheitliches Muster in ihrer Enzymproduktion und daher können einige der Enzymtests zur Differenzierung der untersuchten Bakterien nutzbringend im Zusammenhang mit anderen biochemischen Tests herangezogen werden.

Cytotoxin production by Escherichia coli O111: H⁻ strain HUS-2 (Hamburg) is associated with a temperate toxin-converting bacteriophage (Tcp-111). E. coli laboratory strain C600 transduced and subsequently lysed by the phage produced and liberated large amounts of a cytotoxin (CT111) which was purified by sequential chromatography. When compared with published procedures for toxin release from viable cells, lysis of the C600 culture by the phage was most effective. By SDS-PAGE CT111 as Shiga toxin from Shigella dysenteriae 1 were shown to consist of two polypeptides of MW 31 kd and 4–5 kd. Both toxins share common antigenic epitopes as revealed by immunoblotting and neutralization studies. With rabbit anti-CT111 toxic activity of only 5 out of 8 clinical E. coli O111 isolates was neutralized suggesting the presence of different cytotoxins in E. coli serogroup O111. Taken together, our data established CT111 as a potent cytotoxin with significant enterotoxic and neurotoxic properties similar or identical to Shiga toxin and to Shiga-like toxin I from E. coli O26:H11 and O157:H7 strains.

The systemic humoral immune response in cystic fibrosis (CF) to outer membrane (OM) proteins of Pseudomonas aeruginosa was investigated as a function of the time of colonization by immunoblotting. OM proteins were prepared from bacteria grown in ion-sufficient, magnesium-depleted, and iron-deficient media. The location of proteins F, H, and I on the blots was verified by monoclonal antibodies. Proteins H2 and H1 were differentiated by the overexpression of H1 under magnesium depletion. Iron-regulated membrane proteins (IRMPs) were recognized by their overproduction under iron limitation. Plasma samples from 43 CF patients and ten healthy adults were analyzed after preadsorption with lipopolysaccharide (LPS). Within the first year of colonization, only two to six specific plasma antibodies to OM proteins were produced. After a strong increase during the second year, long-lasting levels were seen in the majority of patients. Large variations of the immune response were noted among the patients. The number of specific antibodies to different OM proteins correlated with the severity of the course of lung disease. At maximum 38 immunostained bands were observed. Proteins H and I were the earliest antigens amongst the major OM proteins. During the second year, antibodies directed to protein F became detectable. IRMPs which indicate the growth of P. aeruginosa under iron deprivation were only recognized by plasma samples from chronically colonized CF patients with advanced lung disease.

Twelve Staphylococcus aureus strains, six positive and six negative for δ-toxin production, were studied for synergistic effects on mouse mortality and morbidity when combined with Candida albicans and inoculated intraperitoneally (i.p.). S. aureus strains producing δ-toxin were found to exhibit a relatively great synergistic decrease (between near 10³–10⁵-fold) in LD₅₀ (dose necessary to kill 50% of exposed animals in five days) when combined with a nonlethal dose of C. albicans and injected i.p. S. aureus strains which did not produce δ showed less of a synergistic effect with C. albicans (10–10²-fold drop in LD₅₀). A synergistic effect on mortality could also be produced when animals were dually injected with C. albicans and sterile growth filtrates from the δ-toxin producing strains or the purified δ-toxin. The lethal agent in the culture filtrate was, like δ-toxin, sensitive to lecithin and insensitive to heat. Indomethacin protected animals from the C. albicans-filtrate induced death. Blood measurements made following i. p. injection of δ-toxin and C. albicans revealed chemistry changes indicative of shock, kidney and liver damage; δ-toxin alone caused no significant chemistry changes whereas C. albicans alone caused some blood chemistry changes but liver and kidney damage was not indicated. No synergism on mortality was found between C. albicans and purified α-toxin or toxic shock syndrome toxin-1.

Certain group A streptococci with surface antigen T 4 possess surface receptors for human haptoglobin (Hp). Binding of ¹²⁵I Hp 2-1 to two representative group A streptococcal cultures could be inhibited by unlabelled Hp 2-1, Hp 2-2 and Hp 1-1 but not by the a1, α² or β chains of Hp. Hp complexes formed with equine hemoglobin and asialo-Hp also reduced ¹²⁵I-Hp 2-1 binding to group A streptococci. Hp binding proteins could be solubilized from streptococcal surface by hot acid treatment of the bacteria and purified by subsequent affinity chromatography on human Hp 2-1 sepharose. The isolated Hp binding proteins specifically inhibited ¹²⁵I-Hp 2-1 binding to group A streptococci and retained their ¹²⁵I-Hp 2-1 binding activity in a dot binding assay on nitrocellulose membranes. SDS-PAGE and protein blots of Hp binding proteins developed with ¹²⁵I-labeled Hp 2-1 revealed numerous high molecular weight proteins with ¹²⁵I-Hp 2-1 binding activity.

Streptokokken der serologischen Gruppe A mit Oberflächenantigen T4 besaßen Bindungseigenschaften für Haptoglobin (Hp) vom Menschen. Die Bindung von I¹²⁵-Hp 2-1 an zwei repräsentative Streptokokkenkulturen der serologischen Gruppe A konnte durch unmarkiertes Hp 2-1, Hp 2-2 und Hp 1-1, nicht aber durch die Hp-Ketten α¹, α² oder β gehemmt werden. Komplexe von Hp mit Hämoglobin vom Pferd und Neuraminsäure-freies Hp führten ebenso zu einer Hemmung der Bindung von I¹²⁵-Hp 2-1. Hp-bindende Proteine der Streptokokkenoberfläche konnten durch Hitzeextraktion bei pH 2,0 abgelöst und durch anschließende Affinitätschromatographie an Hp 2-1-Sepharose gereinigt werden. Die isolierten Hp-bindenden Proteine hemmten spezifisch die Bindung von I¹²⁵-Hp 2-1 an Gruppe A-Streptokokken und wiesen auch in einem “Dot”-Bindungstest auf Nitrozellulosemembranen I¹²⁵-Hp 2-1-Bindungsaktivitäten auf. SDS-PAGE und “Protein blot” der Hp-bindenden Proteine ergaben zahlreiche hochmolekulare Proteine mit I¹²⁵-Hp-Bindungs-aktivität.

A gene coding for the bacterial plasminogen activator staphylokinase (SAK) was cloned from Staphylococcus aureus bacteriophage 42D into an exoprotease reduced mutant strain of Bacillus subtilis (1). Yields of up to 50 mg SAK per litre of culture supernatant were obtained depending on the medium used. SAK purified by ion exchange chromatography and gel filtration had a specific activity of 16 000 units/mg protein. Isoelectric focusing of the purified SAK revealed heterogeneity with respect to the isoelectric points. Four different SAK proteins were identified among which the majority fraction had an IEP of 6.3 and a N-terminal amino acid sequence of NH₂-Lys-Gly-Asp… This N-terminus was 10 amino acids downstream of the expected signal peptide cleavage site beyond AA 27. It resulted most likely from a postsecretory proteolytic modification of the transiently appearing and correct processing product. In contrast to other plasminogen activators SAK was found to be resistant to proteolytic inactivation by plasmin.

Das Gen für den bakteriellen Plasminogenaktivator Staphylokinase (SAK) wurde aus dem Staphylococcus aureus-Bakteriophagen 42D in Bacillus subtilis kloniert (1). In Abhängigkeit vom verwendeten Medium wurden Ausbeuten bis zu 50 mg SAK per Liter Kulturüberstand erreicht. Mittels Ionenaustauschchromatographie und Gelfiltration gereinigte SAK hatte eine spezifische Aktivität von 16 000 Einheiten/mg Protein. Isoelektrische Fokussierung gereinigter SAK zeigte eine Heterogenität des Präparats hinsichtlich der isoelektrischen Punkte. Vier verschiedene Staphylokinaseproteine wurden identifiziert, von denen die Majoritätsfraktion einen IEP von 6,3 und eine N-terminale Aminosäuresequenz von NH₂-Lys-Gly-Asp… aufwies. Dieser N-Terminus lag 10 Aminosäuren stromabwärts des erwarteten Signalpeptidspaltortes. Dies ist wahrscheinlich auf eine postsekretorische proteolytische Modifikation des kurzlebigen korrekten Processing-Produktes zurückzuführen. Im Gegensatz zu anderen bekannten Plasminogenaktivatoren war SAK resistent gegen proteolytische Inaktivierung durch Plasmin.

The assimilation of carbon substrates by 103 strains of Aeromonas of different origin identified by conventional methods was studied by means of a standardized micromethod containing 147 tests (API system). Six disctint groups could be recognized and the discriminating substrates were determined. 3 species of Aeromonas can be identified by means of conventional method: A. hydrophila, A. sobria and A. caviae. The method has a number of drawbacks: Some media are unreliable, others are difficult to read, strict preservation conditions are essential. The proposed micromethod for carbon substrate assimilation allows, in most cases, a simple separation of the 3 motile Aeromonas species.

Mit Hilfe einer standardisierten Mikromethode aus 147 Tests (API-System) wurde die Assimilation von Kohlenstoff-Substraten durch 103 mit konventionellen Verfahren identifizierten Aeromonas-Stämmen verschiedener Herkunft untersucht. Es konnten sechs Gruppen deutlich unterschieden und die zur Unterscheidung dienenden Substrate bestimmt werden. 3 Aeromonas-Arten ließen sich mit Hilfe des konventionellen Verfahrens identifizieren: A. hydrophila, A. sobria and A. caviae. Das Verfahren hat eine Reihe von Nachteilen: Einige Medien sind unzuverlässig, andere schwierig abzulesen, strikte Konservierungsbedingungen sind wesentlich. Die vorgeschlagene Mikromethode zur Kohlenstoff-Substrat-Assimilierung ermöglicht in den meisten Fällen eine einfache Trennung der 3 motilen Aeromonas-Arten.