Integron-mediated rifampin resistance in Pseudomonas aeruginosa.
(33/9595)
A new rifampin resistance gene, arr-2, has been found in Pseudomonas aeruginosa. The ARR-2 protein shows 54% amino acid identity to the rifampin ADP-ribosylating transferase encoded by the arr gene from Mycobacterium smegmatis. This arr-2 gene is located on a gene cassette within a class I integron. (+info)
Pseudomonas aeruginosa: a survey of resistance in 136 hospitals in Spain. The Spanish Pseudomonas aeruginosa Study Group.
(34/9595)
We carried out a nationwide study with all of the isolates of Pseudomonas aeruginosa collected in a week in 136 hospitals in Spain. The data on 1,014 isolates included resistance to the following antimicrobials: piperacillin-tazobactam, 7%; meropenem, 8%; amikacin, 9%; tobramycin, 10%; piperacillin, 10%; ticarcillin, 13%; imipenem, 14%; ceftazidime, 15%; cefepime, 17%; ciprofloxacin, 23%; aztreonam, 23%; ofloxacin, 30%; gentamicin, 31%. The most frequent serotypes were O:1 (25.1%), O:4 (21.6%), and O:11 (11.3%). (+info)
beta-lactamase stability of HR 756, a novel cephalosporin, compared to that of cefuroxime and cefoxitin.
(35/9595)
The stability to beta-lactamase hydrolysis of HR 756, a new cephalosporin antibiotic, was compared to the beta-lactamase stability of cefoxitin and cefuroxime. HR 756, cefoxitin, and cefuroxime were not hydrolyzed by Richmond type I, III, IV, and V beta-lactamases. Antibacterial activity of HR 756 correlated well with resistance to beta-lactamase hydrolysis except against Pseudomonas aeruginosa. HR 756, cefoxitin, and cefuroxime inhibited type I beta-lactamases, but not type III, IV, or V enzymes. HR 756 was the most active inhibitor. (+info)
Effect of different lots of Mueller-Hinton agar on the interpretation of the gentamicin susceptibility of Pseudomonas aeruginosa.
(36/9595)
Population distributions and quality control data for strains of Pseudomonas aeruginosa tested for gentamicin susceptibility on six lots of Mueller-Hinton agar were analyzed. The lots of agar were used in three University of Washington hospitals from April 1975 through October 1977. The analyses indicated that the performance of members of the P. aeruginosa populations in each hospital closely followed the performance of the quality control strain, P. aeruginosa ATCC 27853, when tested on each lot of Mueller-Hinton medium. The variability of zone diameters with the P. aeruginosa populations and the quality control strain indicated that a fixed indeterminate range (13 to 16 mm) of gentamicin susceptibility was not applicable to these organisms as it was with the Enterobacteriaceae. Variability in gentamicin susceptibility results was demonstrated in both minimal inhibitory concentration and disk diffusion tests when eight selected P. aeruginosa strains and the quality control strain were tested on each lot of medium. This variation in susceptibility to gentamicin was not related to the total Ca(2+), Mg(2+), or Zn(2+) content of each lot of medium. The data demonstrated that a moving indeterminate range of gentamicin susceptibility, 3 to 6 mm below the mean zone diameter of the quality control strain, was a suitable criterion for strains tested on a single medium lot. These results illustrate the importance of defining stringent performance standards for media used in the susceptibility testing of P. aeruginosa with gentamicin and other aminoglycoside antibiotics. (+info)
In vitro activity of 5-episisomicin in bacteria resistant to other aminoglycoside antibiotics.
(37/9595)
Eighty-seven isolates of Pseudomonas, Enterobacteriaceae, and Staphylococcus, chosen because of their resistance to other aminoglycosides, were tested for susceptibility to 5-episisomicin. Tests were performed in Mueller-Hinton agar and also, with 38 of these isolates, in Mueller-Hinton broth. Of Enterobacteriaceae, 85 and 95.5% were inhibited by 5 and 10 mug of 5-episisomicin per ml, respectively. Amikacin inhibited 74 and 91% of the strains at 10 and 20 mug/ml, respectively. Fifty-four percent of P. aeruginosa were inhibited by 5-episisomicin and amikacin. Eighty-three percent of S. aureus were inhibited by netilmicin and amikacin, whereas only 50% were inhibited by 5-episisomicin. Isolates resistant to 5-episisomicin were most often resistant to the other aminoglycosides and occurred in gram-negative bacilli that did not carry aminoglycoside-modifying enzymes. Five of 23 isolates that carried a 6'-N-acetyltransferase (AAC-6') and one of two that carried an aminoglycoside 3-acetyltransferase were resistant to and acetylate 5-episisomicin. Strains carrying other aminoglycoside-modifying enzymes were inhibited by 5-episisomicin. Thus, 5-episisomicin is a promising aminoglycoside not attacked by most aminoglycoside-modifying enzymes. Resistance will probably most often be based upon nonenzymatic mechanisms which will also affect other aminoglycosides. (+info)
Analysis of the interactions between piperacillin, ticarcillin, or carbenicillin and aminoglycoside antibiotics.
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Enhanced activity against clinical isolates of Pseudomonas aeruginosa was demonstrated with piperacillin, ticarcillin, and carbenicillin in combination with gentamicin, tobramycin, and amikacin. (+info)
Proposed ticarcillin disk control values for Escherichia coli and Pseudomonas aeruginosa: multicenter cooperative study.
(39/9595)
In a multicenter cooperative controlled study, individual test, accuracy, and precision control values were determined for 75-mug ticarcillin disks with Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853. (+info)
In vitro comparison of kanamycin, kanendomycin, gentamicin, amikacin, sisomicin, and dibekacin against 200 strains of Pseudomonas aeruginosa.
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The antimicrobial activity of kanamycin, kanendomycin, gentamicin, amikacin, sisomicin, and dibekacin against 200 strains of Pseudomonas aeruginosa was compared. Dibekacin was found to be the most active against the tested organisms, whereas the other aminoglycoside antibiotics fell in the following order of diminishing antibacterial potency: amikacin, sisomicin, gentamicin, kanendomycin, and kanamycin. Seven strains showed high-level resistance to gentamicin (minimal inhibitory concentration, 400 mug/ml), and two of them were also resistant to amikacin and sisomicin (minimal inhibitory concentration, 75 mug/ml). The minimal inhibitory concentration of dibekacin for these seven strains was 0.625 mug/ml. (+info)