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Biomedical subjects

A L Barry

Publications and source records attributed to A L Barry.

At least 163 records · Page 9Linked to original sources
PubMed1990

In vitro evaluation of WIN 57273, a new broad-spectrum fluoroquinolone.

WIN 57273 is a new fluoroquinolone that has an expanded spectrum of activity against Staphylococcus spp. (MIC for 90% of isolates [MIC90], 0.008 microgram/ml), Enterococcus faecalis (MIC90, 0.06 microgram/ml), Bacillus spp. (MIC90, 0.03 micrograms/ml), Listeria monocytogenes (MIC90, 0.06 microgram/ml), Streptococcus spp. (MIC90, 0.03 microgram/ml), and Bacteroides fragilis group strains (MIC90, 0.5 microgram/ml). Like other fluoroquinolone compounds, WIN 57273 was active against members of the family Enterobacteriaceae (97% of strains inhibited by less than or equal to 2 micrograms/ml), Haemophilus, Branhamella, and Neisseria strains (100% susceptible), Acinetobacter spp. (100% susceptible), and Pseudomonas aeruginosa (68% susceptible). We observed that WIN 57273 was very active against cephalosporin- or aminoglycoside-resistant gram-negative strains but shared cross-resistance with other fluoroquinolones. Increasing inoculum concentrations had minimal effects on WIN 57273 MICs, and the drug was considered to be bactericidal based on reference MBC and kill curve analyses. Unlike most previously studied drugs in this class, WIN 57273 had increased activity (three- to fourfold) at low pH. Rates of mutation to WIN 57273 resistance at eight times its MIC were in the range of 5.6 x 10(-8) to greater than 1.4 x 10(-9). This new compound possesses a wide potential spectrum of use, and it should be evaluated further by in vitro and in vivo studies.

4-Quinolones↗
PubMed1990

In vitro antibacterial spectrum of E1040 compared with those of cefpirome and ceftazidime and disk diffusion interpretive criteria for E1040.

E1040 is a new parenteral cephalosporin which was tested against 690 clinical isolates and compared with cefpirome and ceftazidime. E1040 had the best activity of the three drugs against Pseudomonas aeruginosa, inhibiting 89% of strains at 8.0 micrograms/ml. E1040 demonstrated good activity against members of the family Enterobacteriaceae, including cefpirome-resistant and ceftazidime-resistant strains. E1040 also had good activity against streptococci but much poorer activity against enterococci and staphylococci. When E1040 broth microdilution and disk diffusion susceptibility test results were compared, the 30-micrograms disk was recommended, with the following tentative interpretive criteria: susceptible, greater than or equal to 18 mm (MIC, less than or equal to 8.0 micrograms/ml); intermediate, 15 to 17 mm (MIC, 16 micrograms/ml); and resistant, less than or equal to 14 mm (MIC, greater than or equal to 32 micrograms/ml).

Bacteria↗
PubMed1990

In vitro activities of ampicillin-sulbactam and cefoperazone-sulbactam against oxacillin-susceptible and oxacillin-resistant staphylococci.

Ampicillin-sulbactam and cefoperazone-sulbactam were tested against staphylococci that were collected from 40 different medical centers throughout the United States. Oxacillin-resistant strains were resistant to both drug combinations, but oxacillin-susceptible strains were uniformly susceptible. The latter included strains with borderline susceptibility to oxacillin and methicillin.

Ampicillin↗
PubMed1990

Interpretive criteria and quality control limits for ceftibuten disk susceptibility tests. Collaborative Antimicrobial Susceptibility Testing Group.

In vitro studies were undertaken to evaluate susceptibility tests with 30-micrograms ceftibuten disks. The following interpretive criteria were proposed: less than or equal to 17 mm for resistance (MIC, greater than or equal to 32 micrograms/ml) and greater than or equal to 21 mm for susceptibility (MIC, less than or equal to 8.0 micrograms/ml). A multilaboratory quality control study led to the conclusion that Escherichia coli ATCC 25922 should provide zones 29 to 35 mm in diameter.

Ceftibuten↗
PubMed1990

Interpretive criteria for disk diffusion susceptibility testing of mupirocin, a topical antibiotic.

Five hundred gram-positive clinical bacterial isolates were tested for susceptibility to mupirocin by broth microdilution and disk diffusion methods (5- and 10-micrograms disks). All but 1 of 330 staphylococci (including 100 oxacillin-resistant Staphylococcus aureus) were susceptible to less than or equal to 1.0 micrograms of mupirocin per ml. With a susceptible MIC breakpoint of less than or equal to 2.0 micrograms/ml, the corresponding zone diameter breakpoints were greater than or equal to 14 mm for 5-micrograms disks and greater than or equal to 16 mm for 10-micrograms disks. With either disk potency, susceptible staphylococci were effectively separated from more resistant gram-positive species such as the enterococci and gram-positive bacilli.

Anti-Bacterial Agents↗
PubMed1990

Implications of beta-lactamase-inhibitor combinations.

Resistance of many species of bacteria to beta-lactam antibiotics is mediated via inactivation by beta-lactamase. Beta-lactamase inhibitors irreversibly bind to beta-lactamases and thus can prevent the destruction of active beta-lactam antibiotics. In the United States three beta-lactam-antibiotic/beta-lactam-inhibitor combinations are commercially available--the orally absorbed amoxicillin/clavulanic acid (A/C), the parenteral formulations of ampicillin/sulbactam (A/S) and ticarcillin/clavulanate (T/C). In a multicenter study that focused on T/C, the in vitro activity of amoxicillin (AMOX), ampicillin (AMP) and ticarcillin (TIC) against Neisseria gonorrhoeae and Haemophilus influenzae was obliterated when beta-lactamase-positive strains were tested, but all tested strains were susceptible to the antibiotics in combination with their respective beta-lactamase inhibitors. Clavulanic acid improved the activity of TIC against most species of Enterobacteriaceae but not against those Enterobacteriaceae that elaborate type I beta-lactamase or against non-Enterobacteriaceae gram-negative bacilli (except for Pseudomonas maltophilia). Staphylococci are generally beta-lactamase positive and considered resistant to AMP and TIC, but greater than 99% of 1,137 Staphylococcus aureus isolates and 92% of coagulase-negative staphylococcal isolates were susceptible to T/C, with comparable figures obtained for A/C and A/S. The activity of TIC against Bacteroides fragilis was improved up to 64-fold by clavulanic acid, with a definite but less pronounced effect on the non-fragilis Bacteroides species. Ninety-seven percent of strains of other anaerobic genera were susceptible to both TIC and T/C.(ABSTRACT TRUNCATED AT 250 WORDS)

Amoxicillin↗
PubMed1989

Quality control parameters and interpretive criteria for in vitro susceptibility tests with the macrolide azithromycin. Collaborative Antimicrobial Susceptibility Testing Group.

Quality control parameters for broth microdilution and disk diffusion susceptibility tests were defined and the interpretive criteria for disk diffusion tests reviewed. For interpretation of tests with 15 micrograms azithromycin disks, the following criteria are recommended: greater than or equal to 19 mm for the susceptible category (MIC less than or equal to 2.0 micrograms/ml) and less than or equal to 15 mm for the resistant category (MIC greater than or equal to 8.0 micrograms/ml). Using these criteria, there was 97% overall agreement between broth dilution and disk diffusion tests; Haemophilus influenzae isolates were susceptible to azithromycin by both methods. The quality control strain Staphylococcus aureus ATCC 25923 gave zones of 21 to 26 mm in diameter in a six-laboratory collaborative study. In azithromycin broth microdilution tests the following MIC control limits are recommended: Escherichia coli ATCC 25922, 2.0-8.0 micrograms/ml; Staphylococcus aureus ATCC 29213, 0.25-1.0 micrograms/ml; and Enterococcus faecalis ATCC 29212, 1.0-4.0 micrograms/ml.

Azithromycin↗
PubMed1989

In-vitro activities of temafloxacin, tosufloxacin (A-61827) and five other fluoroquinolone agents.

Tosufloxacin (A-61827) is the tosylate salt of A-60969 (T-3262). Temafloxacin (A-62254) is the hydrochloride salt of A-63004. Both compounds were tested against 945 aerobic bacterial isolates and their in-vitro activities were compared to those of five other fluoroquinolones. Ciprofloxacin and tosufloxacin were similar in their activity against the Enterobacteriaceae and Pseudomonas species. Temafloxacin and ofloxacin were similar in their activity against the Gram-negative bacilli. Strains that were susceptible to ciprofloxacin were also susceptible to ofloxacin, temafloxacin and tosufloxacin. Against nalidixic acid-resistant enteric bacilli, the potency of all seven fluoroquinolones was compromised. Enoxacin and fleroxacin were the least active drugs against Gram-positive species. Tosufloxacin was particularly active against the Gram-positive species; ciprofloxacin, difloxacin and temafloxacin were less active.

4-Quinolones↗
PubMed1989

In-vitro activity of the penem, FCE 22101, and tentative interpretive criteria for disc susceptibility tests.

The in-vitro activities of two penems (FCE 22101 and SCH 34343) were compared to those of a carbapenem (imipenem), a monobactam (aztreonam) and three cephalosporins (cefoperazone, ceftazidime, and cefotaxime). FCE 22101 displayed a broad spectrum of antibacterial activity against both Gram-negative and Gram-positive pathogens, including anaerobic bacteria. Imipenem and aztreonam, however, were a little more potent against susceptible species. FCE 22101 was bactericidal against 14 of 18 isolates tested; one strain each of Enterobacter cloacae, Staphylococcus aureus (methicillin sensitive), Staph. aureus (methicillin resistant) and Streptococcus faecalis were not killed by FCE 22101. For disc diffusion tests, a 10 micrograms FCE 22101 disc is tentatively recommended with zones of less than or equal to 13 mm for resistant (MIC greater than 8.0 mg/l) and greater than or equal to 17 mm for susceptible (MIC less than or equal to 4.0 mg/l). Those criteria need to be reevaluated when additional pharmacokinetic information and clinical experience have been gathered.

Anti-Bacterial Agents↗
PubMed1989

In-vitro studies of meropenem.

Meropenem, a new carbapenem, was compared with imipenem and seven other broad-spectrum antimicrobial agents against approximately 1000 clinical isolates. Meropenem was two- to four-fold more active than imipenem against Gram-negative organisms and its spectrum of antimicrobial activity was wider than those of all other drugs tested. However, imipenem was more potent than meropenem against the staphylococci, Streptococcus spp. and enterococci. Many rarely isolated organisms were more susceptible to the carbapenems than to other comparison compounds. All anaerobic bacteria were inhibited by meropenem at less than or equal to 8 mg/l and 50% of strains were inhibited by 0.25 mg/l. Meropenem MICs were not significantly influenced by high inocula and the drug was generally bactericidal. Strains producing various beta-lactamases remained susceptible to meropenem but some isolates producing high levels of chromosomally-mediated enzymes showed an inoculum effect only at 10(7) cfu/ml. Meropenem demonstrated antagonism with several other beta-lactams against strains producing Type I cephalosporinases. Susceptibility tests performed on agar and in broth produced very similar meropenem results. Imipenem and meropenem shared a high degree of cross-susceptibility as measured by dilution test methods. Disc diffusion (10-micrograms disc) regression-line correlations with meropenem MICs are reported with two possible sets of interpretive criteria, using meropenem breakpoints of less than or equal to 2 and less than or equal to 4 mg/l.

Anti-Bacterial Agents↗
PubMed1989

Multicenter in vitro evaluation of SM-7338, a new carbapenem.

A new carbapenem, SM-7338, was compared with imipenem, cefotaxime, and ceftazidime at five medical centers. Nearly 6,000 strains were tested by reference methods of the National Committee for Clinical Laboratory Standards, and SM-7338 inhibited the largest percentage of gram-negative bacilli. Its spectrum included all members of the family Enterobacteriaceae (99.7% were susceptible to less than or equal to 4 micrograms/ml), Pseudomonas spp. (but not Xanthomonas maltophilia), and Acinetobacter spp. The potency and spectrum of SM-7338 against the gram-positive organisms were less than those of imipenem and superior to those of ceftazidime. Only the enterococci and some oxacillin-resistant staphylococci were less susceptible to SM-7338 (MICs for 90% of isolates, greater than or equal to 8 micrograms/ml). Organisms resistant to ceftazidime were generally susceptible to SM-7338 and imipenem (76%). However, for one-third of the imipenem-resistant gram-negative bacilli (MICs, greater than 8 micrograms/ml), SM-7338 MICs were less than or equal to 4 micrograms/ml. Some endemic differences in patterns of SM-7338 activity against selected gram-negative species were found among some medical centers.

Anti-Bacterial Agents↗
PubMed1989

Antibacterial activity of trospectomycin (U-63366F) and initial evaluations of disk diffusion susceptibility tests.

The in vitro activities of trospectomycin sulfate were compared with those spectinomycin against 632 aerobic microorganisms, including 66 Neisseria gonorrhoeae isolates. Against species other than gram-negative bacilli, trospectomycin was about 4- to 16-fold more active than spectinomycin. For disk diffusion tests, a 30-micrograms disk is recommended, with tentative zone size breakpoints of less than or equal to 13 mm for resistance (MIC, greater than or equal to 64 micrograms/ml) and greater than or equal to 17 mm for susceptibility (MIC, less than or equal to 16 micrograms/ml).

Anti-Bacterial Agents↗