Biomedical subjects

A L Barry

Publications and source records attributed to A L Barry.

At least 289 records · Page 16Linked to original sources

PubMed1985

Ciprofloxacin disk susceptibility tests: interpretive zone size standards for 5-microgram disks.

Evaluations of 5-microgram ciprofloxacin disk diffusion susceptibility tests were performed independently by seven different investigators. The results of the separate tests were combined to increase the number of resistant strains in the challenge set of microorganisms. Based on data with 2,652 isolates, the following interpretive breakpoints are tentatively proposed for use in ongoing clinical trials of ciprofloxacin: less than or equal to 15 mm, resistant (MIC greater than 2.0 micrograms/ml); 16 to 20 mm, intermediate (1.0 less than MIC less than or equal to 2.0 micrograms/ml); and greater than or equal to 21 mm, susceptible (MIC less than or equal to 1.0 micrograms/ml). Disk tests with Streptococcus spp. and with Pseudomonas maltophilia were not reliable; other microorganisms were accurately categorized by the disk diffusion test.

Acinetobacter↗

PubMed1985

Proposed disk diffusion susceptibility criteria for ofloxacin.

Disk diffusion zone diameter breakpoint criteria for ofloxacin were tentatively established by correlating MICs with 1-, 3-, and 5-micrograms disk inhibitory zone diameters for 638 bacterial isolates representing 36 species. We recommend use of 5-micrograms disks with the following breakpoints: susceptible (MIC, less than or equal to 2.0 micrograms/ml), greater than or equal to 16 mm; intermediate (MIC, 4.0 micrograms/ml), 13 to 15 mm; and resistant (MIC, greater than or equal to 8.0 micrograms/ml), less than or equal to 12 mm.

Anti-Bacterial Agents↗

PubMed1985

Interpretive standards and quality control guidelines for cefpiramide disk susceptibility tests.

Disk susceptibility tests with 30- and 75-micrograms cefpiramide disks were evaluated with 614 bacterial isolates. Quality control parameters were also evaluated, and control limits for disk tests are recommended. Tests with 75-micrograms disks are recommended, with zone size standards of greater than or equal to 19 mm for susceptible (MIC, less than or equal to 32 micrograms/ml) and less than or equal to 15 mm for resistant (MIC, greater than or equal to 128 micrograms/ml).

Cephalosporins↗

PubMed1985

Cefoperazone and cefoperazone-sulbactam susceptibility tests with anaerobic bacteria by the thioglycolate disk elution method.

Tests were performed with 104 anaerobic microorganisms to evaluate the thioglycolate disk elution technique for the detection of resistance to cefoperazone and cefoperazone-sulbactam. An unacceptably high false-resistance rate and a poor reproducibility record make the disk elution procedure unsatisfactory for routine testing of this drug or combination of drugs.

Bacteria, Anaerobic↗

PubMed1985

Cefotiam susceptibility testing criteria.

Interpretive zone size breakpoints for diffusion tests with 30-micrograms cefotiam disks are diameters of greater than or equal to 18 mm for susceptible and less than or equal to 14 mm for resistant strains. The standard control strains Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 should both give zones 27 to 33 mm in diameter. Tests with 579 clinical isolates yielded an unacceptably high rate of very major discrepancies between disk tests and microdilution tests; such discrepancies were especially common among Enterobacter spp. Additional studies support the concept that standard microdilution tests and standard disk diffusion tests may fail to detect a potential for resistance among some microorganisms.

Cefotaxime↗

PubMed1985

Simple and rapid methods for bacterial identifications.

Simple, inexpensive procedures for rapid identification of the common bacterial pathogens are outlined in detail. When the tests are judiciously applied, most isolates can be identified within minutes or hours, and strains that require more extensive testing for accurate identification will be recognized.

Acetoin↗

PubMed1984

3-0-demethyl fortimicin A: in vitro activity and interpretive zone standards for disk diffusion susceptibility tests.

The in vitro activity of 3-0-demethyl fortimicin A was compared to that of amikacin and tobramycin against 5,230 clinical isolates in four institutions. Amikacin and tobramycin were more active than 3-0-demethyl fortimicin A against Pseudomonas aeruginosa and Acinetobacter spp., but all three drugs had similar activity against the Enterobacteriaceae and Staphylococcus aureus. Additional tests with 335 representative gram-negative bacilli compared five different aminoglycosides, demonstrating differences with some isolates. Standardized disk diffusion tests were also performed with 30 micrograms 3-0-demethyl fortimicin A disks, according to the National Committee for Clinical Laboratory Standards. The following interpretive breakpoints are proposed: less than or equal to 11 mm for resistant (MIC greater than or equal to 32 micrograms/ml) and greater than or equal to 15 mm for susceptible (MIC less than or equal to 16 micrograms/ml).

Acinetobacter↗

PubMed1984

In vitro activity of ticarcillin plus clavulanic acid against bacteria isolated in three centers.

Over 10,000 bacterial isolates were tested against ticarcillin alone or combined with clavulanic acid (2.0 micrograms/ml). Of 5,295 Enterobacteriaceae, 72% were susceptible to ticarcillin alone, whereas 91% were susceptible to the combination. Bacteroides fragilis and Bacteroides melaninogenicus isolates were more susceptible to the combination. The activity of ticarcillin against other microorganisms was not profoundly influenced.

Anti-Bacterial Agents↗

PubMed1984

Temocillin: in vitro activity against 734 selected clinical isolates, including beta-lactamase-producing strains.

The in vitro activity of temocillin against 734 clinical isolates was tested by broth microdilution. Good activity was demonstrated against Enterobacteriaceae and both beta-lactamase-positive and -negative strains of Haemophilus influenzae and Neisseria gonorrhoeae. There was little to no activity against gram-positive cocci and nonfermenting gram-negative bacilli. Bactericidal activity and effect of inoculum size on temocillin activity were comparable to that of ticarcillin. Temocillin was stable to commonly encountered beta-lactamases and significantly inhibited Richmond-Sykes type 1 enzymes of Enterobacter cloacae.

Bacteria↗

PubMed1984

Emergence of Streptococcus faecalis isolates with high-level resistance to multiple aminocyclitol aminoglycosides.

Isolates of Streptococcus faecalis were occasionally found to be resistant to gentamicin concentrations of 500 micrograms/ml in a microdilution tray. Additional tests were performed with 28 such isolates. They all demonstrated high-level resistance (minimum inhibitory concentration greater than 2000 micrograms/ml) to gentamicin, kanamycin, sisomicin, streptomycin, and tobramycin. This high-level aminoglycoside resistance was associated with total resistance to in vitro synergism when each aminoglycoside was combined with ampicillin. In addition to ampicillin-aminoglycoside combinations, ampicillin-vancomycin, ampicillin-rifampin, rifampin-vancomycin, and vancomycin-gentamicin combinations were also tested; all failed to exhibit an in vitro synergistic-bactericidal effect against these enterococci. The emergence of enterococci with high-level resistance to multiple aminoglycosides in this clinical population is a source of grave concern with obvious therapeutic implications in situations such as endocarditis, where an in vitro bactericidal effect is thought to be necessary for a cure. No drug or combination of drugs was found to be bactericidal for these isolates. It is suspected that similar isolates of group D streptococci with high-level resistance to gentamicin may emerge in other institutions but go unrecognized. Surveillance by others for identifying this newly emerging pathogen carrying multiple resistance and a continued search for a satisfactory chemotherapeutic agent(s) are encouraged.

Aminoglycosides↗

PubMed1984

Unpredictable interactions between cefotetan and penicillins or aminoglycosides.

The bacteriostatic and bactericidal activity of gentamicin, amikacin, piperacillin, azlocillin, ampicillin, benzyl penicillin, and oxacillin against 85 selected isolates was measured alone and in the presence of subinhibitory concentrations of cefotetan. A potential for antagonistic interactions between cefotetan and acylamino penicillins (piperacillin greater than azlocillin greater than ampicillin) were observed with some strains; synergy was suggested with other isolates, however, Bacteriostatic and bactericidal activity of the two aminoglycosides was enhanced by cefotetan with most gram-negative bacilli, but bactericidal activity was significantly diminished with 4 of 65 strains. Piperacillin and cefotetan were clearly antagonistic with 11 of 44 strains and synergistic with 4 of 44 strains of gram-negative bacilli: the remaining 21 strains gave off scale end points and could not be analyzed in that way.

Aminoglycosides↗

PubMed1984

In vitro activity of ticarcillin plus clavulanic acid against 632 clinical isolates.

A total of 632 clinical bacterial isolates were tested for susceptibility to twofold dilutions of ticarcillin alone and in combination with 1, 2, and 4 micrograms of clavulanic acid (CA) (Timentin) per ml by a reference microdilution method. With the addition of CA, ticarcillin MICs were reduced eightfold or greater with 54 of 59 (92%) strains of the family Enterobacteriaceae with ticarcillin MICs of greater than or equal to 64 micrograms/ml. The inhibitory effect of CA on pseudomonads was minimal. Ticarcillin MICs for beta-lactamase-producing Haemophilus influenzae, Neisseria gonorrhoeae, and most Staphylococcus aureus were reduced to less than or equal to 0.5 micrograms/ml when CA was added. For dilution susceptibility testing of ticarcillin-clavulanic acid, dilutions of ticarcillin combined with 2 micrograms of CA per ml is suggested.

Bacteria↗

PubMed1984

Antibacterial activities of ciprofloxacin, norfloxacin, oxolinic acid, cinoxacin, and nalidixic acid.

In vitro studies were performed comparing ciprofloxacin (Bay o 9867) and norfloxacin with three related organic acids. Ciprofloxacin was two to eight times more active than norfloxacin against 658 bacterial isolates representing 30 species. For all species tested, ciprofloxacin MICs for 90% inhibition were less than or equal to 2.0 micrograms ml. Additional tests with 5,994 isolates detected only 37 (0.6%) strains resistant to 2.0 micrograms of ciprofloxacin per ml and 106 (1.8%) resistant to 1.0 micrograms/ml. Only 6 (0.1%) of the 5,994 strains were resistant to 16 micrograms of norfloxacin per ml, and 129 (2.1%) were resistant to 4.0 micrograms/ml. The majority of resistant strains were streptococci or Pseudomonas spp. Resistance among the Enterobacteriaceae was extremely rare (i.e., greater than 99.8% susceptible to both drugs.

Anti-Bacterial Agents↗

PubMed1984

In vitro activity of apalcillin compared with those of piperacillin and carbenicillin against 6,797 bacterial isolates from four separate medical centers.

Quantitative susceptibility tests were performed in four separate medical centers, in which apalcillin was compared with piperacillin and carbenicillin. Data from tests of 6,797 isolates confirmed that apalcillin and piperacillin had nearly identical spectra of activity but that apalcillin was significantly more active against Pseudomonas aeruginosa (MIC required to inhibit 90% of strains, 2.0 versus 64 micrograms/ml) and Acinetobacter calcoaceticus subsp. anitratus (MIC required to inhibit 90% of strains, 2.0 versus 16 micrograms/ml). Against 166 anaerobic bacterial isolates, apalcillin demonstrated in vitro activity.

Ampicillin↗

PubMed1984

In vitro evaluation of HR810, a new wide-spectrum aminothiazolyl alpha-methoxyimino cephalosporin.

HR810 (Hoechst-Roussel Pharmaceuticals Inc., Somerville, N.J.) is a new, cyclical-pyridinium cephalosporin that appeared superior to numerous comparison drugs against 658 strains of aerobic and facultative anaerobic bacteria. Seventeen Enterobacteriaceae spp. were tested by broth microdilution methods, and the 50% MICs (MIC50S) and 90% MICs (MIC90s) were 0.03 to 0.12 and 0.03 to 2.0 micrograms/ml, respectively. Only one strain had an MIC greater than 8.0 micrograms/ml (99.6% is considered susceptible). HR810 inhibited 98% of Pseudomonas aeruginosa isolates at less than or equal to 16 micrograms/ml, and the MIC90 for Acinetobacter spp. was 4.0 micrograms/ml. It was also very active against Pseudomonas spp. and Staphylococcus aureus (MIC90, 0.5 micrograms/ml) but marginally active against methicillin-resistant staphylococcal strains (MIC90, 16 micrograms/ml) and enterococcus (MIC90, 32 micrograms/ml). Non-enterococcal streptococci had MIC50s ranging from 0.008 micrograms/ml for Streptococcus pyogenes to 0.12 micrograms/ml for pneumococci. All MICs of HR810 against Haemophilus and Neisseria spp. were less than or equal to 0.03 micrograms/ml (MIC50, 0.002 to 0.008 micrograms/ml). HR810 poorly inhibited beta-lactamases and was very stable against 11 tested beta-lactamases of plasmid (TEM, OXA, SHV-1, and PSE) and chromosomal (K1, K14, P99) types.

Anti-Bacterial Agents↗

PubMed1984

Cross-resistance among cinoxacin, ciprofloxacin, DJ-6783, enoxacin, nalidixic acid, norfloxacin, and oxolinic acid after in vitro selection of resistant populations.

Six different gram-negative bacilli were serially transferred through subinhibitory concentrations of seven quinolone derivatives or related organic acids. A gradual, stepwise decrease in susceptibility was noted with all seven drugs, and the resistant cultures demonstrated a concomitant cross-resistance to the other drugs.

Anti-Bacterial Agents↗

PubMed1984

Interpretive standards and quality control limits for susceptibility tests with ampicillin-sulbactam combination disks.

In vitro studies were performed to evaluate susceptibility tests with disks containing 10 micrograms of ampicillin plus 10 micrograms of sulbactam. Interpretive zone standards of less than or equal to 11 mm (resistant), 12 to 13 mm (intermediate), and greater than or equal to 14 mm (susceptible) are proposed. A nine-laboratory coordinated study was performed to establish tentative zone size limits for quality control of ampicillin-sulbactam disks. This included data with a new control strain selected to monitor performance of such combination disks.

Acinetobacter↗

PubMed1984

Modification of interpretive breakpoints for netilmicin disk susceptibility tests with Pseudomonas aeruginosa.

Regression analysis of data correlating 30-micrograms netilmicin disk zone diameters with microdilution MICs, obtained by testing close-interval dilution steps, was performed with 77 selected strains of Pseudomonas aeruginosa, each tested in three independent laboratories. A zone of greater than or equal to 15 mm correlated with an MIC of less than or equal to 12 micrograms/ml (susceptible), and a zone of less than or equal to 12 mm correlated with an MIC of greater than 16 micrograms/ml (resistant). Additional disk tests were performed with 256 strains having known resistance mechanisms and 280 susceptible strains: the majority were appropriately categorized by these interpretive zone standards. The previously recommended standards of greater than or equal to 17 mm (MIC, less than or equal to 8.0 micrograms/ml) for the susceptible category inappropriately placed a significant number of truly susceptible P. aeruginosa strains in the intermediate category.

Drug Resistance, Microbial↗