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M Kettner

Publications and source records attributed to M Kettner.

At least 19 recordsLinked to original sources
PubMed2004

Occurrence of endemic plasmids causing beta-lactam resistance in Enterobacteriaceae in children's university hospital in Munich.

Susceptibility of 62 clinical isolates of Enterobacteriaceae to 15 aminoglycosides, beta-lactams and fluoroquinolones was determined. The isolates originating from 3 intensive care units (neonatal, pediatric, and surgical) and the Department of Infant Internal Medicine of the Children's University Hospital City Center in Munich (Germany) were collected in August 1999, and March and October 2000. Transferability of antibiotic resistance from donors to their E. coli transconjugants was also demonstrated. The majority of isolates were resistant to ampicillin, cefoxitin, ceftriaxone, cefotaxime, ceftazidime and azthreonam but they were susceptible to cefepime, meropenem, aminoglycosides and fluoroquinolones. The occurrence of beta-lactamases and extended-spectrum beta-lactamases (ESBL) was also shown. In August 1999 75% of isolates produced beta-lactamases and 15% ESBL, in March 2000 95% of isolates produced beta-lactamases and 9% ESBL; in October 2000 all isolates produced beta-lactamases and only 5% produced ESBL. Plasmid DNA analysis in randomly chosen isolates and their transconjugants revealed the presence of plasmids ranging from 19 to 136 kb; in the majority of isolates a 120-kb plasmid was observed. Further analysis using restriction endonuclease suggested a dissemination and persistence of an endemic plasmid at all 4 wards of the large pediatric hospital in the City Center of Munich which may be responsible for resistance to beta-lactams among Enterobacteriaceae isolates.

Child↗
PubMed2001

Occurrence and transferability of beta-lactam resistance in Enterobacteriaceae isolated in Children's University Hospital in Bratislava.

Occurrence and transferability of beta-lactam resistance in 30 multi-resistant Escherichia coli, Klebsiella spp., Enterobacter spp., Pantoea agglomerans, Citrobacter freundii and Serratia marcescens strains isolated from children between 0 and 3 years of age is presented. The strains were resistant to ampicillin (30), cefoxitin (22), cefotaxime (30), ceftriaxone (30), ceftazidime (30) and aztreonam (28), but susceptible to cefepime (30) and imipenem (26). Twenty-eight of 30 isolates possessed a transferable resistance confirmed by conjugation and isolation of 79-89-kb plasmids. The beta-lactam resistance was due to production of beta-lactamases and ceftazidime proved to be stronger beta-lactamase inductor than ceftriaxone. Twenty-five clinical isolates expressed transferable extended spectrum beta-lactamases, and chromosomally encoded AmpC beta-lactamase.

Anti-Bacterial Agents↗
PubMed2001

[Occurrence and mechanisms of resistance to beta-lactam antibiotics in clinically important species of Enterobacter].

Extended-spectrum beta-lactam antibiotics have found great medical importance, but their wide use in clinical practice leads to increasing resistance to them. The more frequent occurrence of infections caused by Bush group 1 beta-lactamase producing organisms, including species of the genus Enterobacter, is a serious problem in this field. Resistance to beta-lactams in this important nosocomial pathogens can be due to 1) reduction in outer membrane permeability to antibiotics caused by alterations in outer membrane lipopolysacharides or proteins (porins); 2) production of beta-lactamases, which inactivate beta-lactams and can also lead to resistance by non-hydrolytic mechanism called trapping. Production of plasmid-mediated extended-spectrum beta-lactamases, but especially chromosomally-mediated inducible cephalosporinase AmpC, which can be synthesized constitutively in large amounts as consequence of spontaneous chromosomal mutations, are of great clinical importance. Fourth-generation cephalosporins and carbapenems are the most effective in the treatment of infections caused by species belonging to the genus Enterobacter, but combination of high level beta-lactamase production and decreased outer membrane permeability, which is not rare in Enterobacter spp., leads to resistance even to these drugs.

Enterobacter↗
PubMed2000

Spectrum and transferability of beta-lactam resistance in hospital strains of Enterobacter isolated in Bratislava and Innsbruck.

The transferability and expression of beta-lactam resistance were compared in multiresistant clinical isolates of Enterobacter spp. collected from different hospitals in Bratislava, Slovakia (n = 15) and Innsbruck, Austria (n = 19) during 1996-1997. The strains from Bratislava were resistant to ampicillin, cefoxitin, cefotaxime, ceftazidime and ceftriaxone. All strains from Innsbruck were resistant to ampicillin and cefoxitin; 17 were also resistant to ceftazidime and aztreonam but the majority remained susceptible to cefotaxime and ceftriaxone. All strains were susceptible to cefepime and imipenem. The majority of the tested strains transferred resistance determinants to E. coli recipient by conjugation. Production of beta-lactamase including ESBL was the major mechanism of beta-lactam resistance. Large plasmids of 77-88 and 91 kb were confirmed in clinical isolates from Bratislava and Innsbruck.

Anti-Bacterial Agents↗
PubMed1998

Study of beta-lactam resistance in ceftazidime-resistant clinical isolates of Enterobacteriaceae.

Mechanisms and transferability of beta-lactam resistance in 50 ceftazidime resistant strains of Enterobacteriaceae was studied. These strains were selected from 1991 E. coli, 1035 Enterobacter spp., 168 Citrobacter spp. and 1371 Klebsiella spp., isolated from patients hospitalized in ICUs and in the pediatric and urology departments of six hospitals in Bratislava during the years 1994-1996. The selected strains expressed the resistance not only to ceftazidime (50/50) but also to ampicillin (50/50), ceftriaxone (50/50), cefotaxime (49/50) and cefoxitin (45/50). The mechanism of resistance in all 50 strains was the production of beta-lactamases by conjugation, using either ceftazidime or cefotaxime for the selection of transconjugants and by isolation of R-plasmids ranging from to 55-87 kb from donor strains and from transconjugants. A total of 21 isolates possessed chromosomally encoded resistance and 25 clinical isolates and their transconjugants expressed ESBL sensitive to clavulanate. Selected E. coli and Klebsiella pneumoniae isolates expressed the presence of TEM and SHV enzymes determined by isoelectric focusing. The possible trends in the development of antimicrobial resistance in Slovakia in the future are indicated.

Anti-Bacterial Agents↗
PubMed1997

Aminoglycoside resistance. Enzymatic mechanisms in clinical bacterial strains in Slovakia during the last decade.

We determined the importance and dissemination of enzymatic mechanisms of aminoglycoside resistance in 239 gentamicin-resistant strains of Gram-negative bacilli isolated in Slovakia during the past decade. Over the past 5 years, the resistance to tobramycin has risen by 1.1% to netilmicin by 27.4%, to amikacin by 78.3%, and resistance to isepamicin was high too (81.9%). Sixteen different aminoglycoside-modifying enzymes were detected and their significance for resistance to aminoglycosides was confirmed. It is evident that within the past 5 years gentamicin-resistant bacterial have obtained genetic information on resistance to the other aminoglycosides tested and the percentage of strains with different enzyme combinations has risen. These observations confirm the continuously increasing complexity of antibiotic resistance in clinical bacterial isolates under study in Slovakia during the last decade.

Anti-Bacterial Agents↗
PubMed1997

[beta-Lactam antibiotics--mechanisms of action and resistance in Enterobacteriaceae].

Beta-lactams are considered to be very important drugs used in the therapy of many serious bacterial infections. In the last few years, the number of isolated clinical strains from the Enterobacteriaceae family, mainly Enterobacter and Klebsiella spp. resistant to 3rd generation cephalosporins, rapidly increased. Resistance can be located on chromosomes or be determined by plasmids and transposons. The production of beta-lactamases is the most frequent manifestation of beta-lactam resistance. Spread of such resistance, especially plasmid-encoded, is believed to be a serious risk factor. Therefore the study of the resistance mechanism is Gram-negative bacilli to beta-lactams not only indicates the present situation, but also trends in future medical therapy.

Anti-Bacterial Agents↗
PubMed1995

[Epidemiology of the distribution of genes coding for resistance to antibiotics].

The increasing prevalence of isolated bacteria resistant to antibiotics is one of the serious problems of contemporary clinical medicine because it is the main cause of failing treatment of infectious diseases. Therefore great efforts are made to reveal the mechanisms of resistance to antibiotics and to elucidate their epidemiology. In the submitted paper the author summarizes the present stage of knowledge concerning mechanisms of resistance to antibiotics and mechanisms of their distribution in nature. In the conclusion the authors draw attention to the important character of transmitted resistance to antibiotics from the aspect of its rapid spread among the microbial population.

Drug Resistance, Microbial↗
PubMed1995

In vitro activity of imipenem and six other beta-lactam antibiotics against aminoglycoside resistant gram-negative bacilli.

The in vitro activity of imipenem and six other beta-lactams (ampicillin, cefamandole, cefoxitin, ceftriaxone, ceftazidime, cefotaxime) against twenty Gram-negative bacilli resistant to clinically important aminoglycosides was studied. The bacterial strains showed high resistance (R) to gentamicin, tobramycin (R 100%), netilmicin (R 75%) and to the beta-lactams ampicillin (R 100%), cephamandole (R 90%) and cefoxitin (R 75%). The strains were susceptible to isepamicin (R 10%) and imipenem (R 10%) as well as susceptible to at least third generation cephalosporin. Three Pseudomonas aeruginosa strains were resistant to the majority of antibiotics, except for imipenem.

Aminoglycosides↗
PubMed1992

[Bacterial resistance to aminoglycoside antibiotics].

Aminoglycoside antibiotics, such as gentamicin, netilmicin, tobramycin, amikacin, may be inactivated by resistant bacteria producing three types of enzymes: O-nucleotidyltransferases, O-phosphotransferases and N-acetyltransferases. Mechanisms of aminoglycoside resistance were analyzed in clinical isolates of gram-negative bacteria from several regions of Czecho-Slovakia and compared with the use of aminoglycosides. Production of acetyltransferases (AAC) and nucleotidyltransferases (ANT) was observed in 84% of bacterial isolates. The majority of bacterial strains studied produced the AAC/3/enzyme (62%). Due to dissemination of plasmids coding for the AAC/3/enzyme, the majority of Czecho-Slovak gentamicin-resistant strains was also tobramycin resistant (93%) and netilmicin resistant (68%). Amikacin remains the most effective aminoglycoside antibiotic against multiresistant bacterial strains.

Aminoglycosides↗
PubMed1992

[Mechanisms of resistance to dactimicin and isepamicin in clinical strains of gram-negative rods isolated in Czechoslovakia].

Dactamicin is a new member of the pseudo-disaccharide group of antibiotics. It is structurally close to astromicin. Dactimicin is active against a wide variety of bacteria, including resistant strains with aminoglycoside-inactivating enzymes. Isepamicin is a broad-spectrum aminoglycoside, a derivative of gentamicin B. It is also active against many aminoglycoside-resistant strains. In a series of gram-negative bacterial isolates from various Czecho-Slovak regions, in vitro investigation yielded a good activity of dactimicin and isepamicin against amikacin- and gentamicin-resistant strains producing the enzyme AAC/6'/ or a combination of AAC/6'/ + ANT/2"/ enzymes. Dactimicin was not effective against strains producing the enzyme AAC/3/-I, and isepamicin was not effective or only slightly effective against bacterial isolates producing a combination of AAC/6'/ + AAC/3/ enzymes. (Tab. 3, Fig. 2, Ref. 10.).

Aminoglycosides↗
PubMed1990

[New quinolines for the treatment of urinary tract infections].

The submitted review draws attention to the role of new quinolones in anti-infectious chemotherapy of the urinary pathways. It gives an account of published results of treatment and prophylaxis of infections of the urinary pathways and the prostate, as compared with hitherto used chemotherapeutic drugs and antibiotics.

4-Quinolones↗
PubMed1990

[The effect of nitrofuran and asymmetrically substituted urea on Trichomonas vaginalis and Tritrichomonas foetus in vitro and in vivo].

Antitrichomonal activity of selected nitrofuran derivatives and asymmetrically substituted ureas was investigated in vitro and in vivo and compared with the activity of the effective therapeutic agent tinidazole. In experimental infection with Trichomonas vaginalis and Tritrichomonas foetus in mice, some substituted urea derivatives exhibited an antiparasitic effect slightly lower than that of tinidazole. The substance N1-(3-nitrophenyl)-N3-(2-pyrimidinyl)urea proved to be the most effective of the substances tested. On the basis of preliminary toxicity tests the chemotherapeutic value of this substance appears to be promising.

Animals↗
PubMed1990

In vivo effect of 2,4-dinitro-phenyl-substituted sugar hydrazones and phenylosazone against Trichomonas vaginalis and Tritrichomonas foetus.

Antitrichomonal activity of selected 2,4-dinitro-phenylhydrazones and phenylosazones of sugars was investigated in vitro and in vivo and compared with the activity of tinidazole, an effective therapeutic agent. In experimental infections with Trichomonas vaginalis and Tritrichomonas foetus in mice glycolaldehyde-2,4-dinitro-phenylhydrazone acetate and 2,3-diacetylglycerolaldehyde-2,4-dinitro-phenylhydrazone exhibited an antiparasitic effect slightly inferior to that of tinidazole. Structure-activity relationships are discussed. On the basis of the results obtained the chemotherapeutic value of the mentioned substances seems to be promising.

Abscess↗
PubMed1989

[Verbal interaction of schizophrenic patients and their conversational partners].

Verbal interactive behavior of 10 male patients diagnosed as schizophrenic, but not acutely psychotic, and of their non-schizophrenic ('normal') and non-informed dialogue-partners are studied in dialogical conversations about political problems. A control group of ten dyads of 'normal' dialogue partners is used for comparisons. Quantitative text-properties (number of words, pauses) as well as a reconstructive hermeneutic analysis of the dialogues reveal a lack of dialogical balance, less task-oriented productivity, and markedly more strained conversation in dyads with a schizophrenic conversand as compared to those of the control group. The schizophrenic conversands we have studied manifest various interactive strategies of withdrawing from active participation in the conversational task, delegating it instead to their respective 'normal' partners who in turn attempt to stimulate more active participation of them. Furthermore, occasional strange utterances occur in nearly all dyads with a schizophrenic and lead to disturbances in the flow of the conversation. We interpret these findings as manifestations of object-relations disturbances and of corresponding deviant modes of regulating personal distance in schizophrenics.

Adaptation, Psychological↗