Omeprazole and lansoprazole are proton pump inhibitors that have shown activity against Helicobacter pylori and other Helicobacter species when tested by agar dilution. Lansoprazole was more active against H. pylori than was omeprazole, and the activity was independent of urease production. Disk susceptibility tests and agar dilution MIC determinations were performed to investigate the effects ...

We read with interest the recently published paper by Piccolomini et al. (7). They evaluated three different methods to study the susceptibility of Helicobacter pylori to 20 antimicrobial agents. They found a very good correlation between E-test and agar dilution methods, as well as between broth microdilution and agar dilution. They recommended the E test as a reliable and alternative method f...

A bioassay for tyrothricin, based on a procedure used by Szybalski in bacterial resistance studies, was developed. Replacement of the tube dilution assay with this procedure represented economy in time and equipment, with a resultant increase in productivity. The procedure involved preparation of special agar plates which provided graded concentrations of tyrothricin along a horizontal axis. A ...

Netilmicin (Sch 20569), a semisynthetic aminoglycoside related to gentamicin C(1a), was evaluated in vitro in agar dilution testing against 224 different clinical isolates of gentamicin-resistant Enterobacteriaceae and Pseudomonas aeruginosa in parallel with amikacin, gentamicin, sisomicin, and tobramycin. Netilmicin showed a very high degree of activity against gentamicin-resistant organisms, ...

The antibiotic susceptibilities of Neisseria gonorrhoeae isolates obtained from patients attending a clinic for sexually transmitted diseases in Tucumán, Argentina, were determined by the agar dilution method (MIC). 3.5% of the isolates produced beta-lactamase. A total of 96.5% of beta-lactamase negative isolates tested were susceptible to penicillin (MIC < or = 2 micrograms/ml-1); 14.03% of th...

In vitro activities of antifungal agents, including azole compounds, against yeasts were easily determined by using RPMI-1640 agar medium and by incubating the plates in the presence of 20% CO2. The end point of inhibition was clear by this method, even in the case of azole compounds, because of the almost complete inhibition of yeast growth at high concentrations which permitted weak growth of...

Considering the emergence of high level aminoglycoside resistance (HLAR) in enterococci this study was undertaken to determine their status in a rural setting. HLAR by disc diffusion and agar dilution, beta lactamase by nitrocefin disc and vancomycin resistance by agar dilution was determined in 150 enterococcal isolates, as per NCCLS guidelines. Only two species, Enterococcus faecalis (85.5%) ...

In this study, we report the antibacterial activities of six polyphenols (i.e., luteolin, quercetin, scutellarin, apigenin, chlorogenic acid, and resveratrol) against 29 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA), and in vitro antibacterial activities of two-drug combinations. All of the MRSA strains evaluated were clinical isolates from patients with MRSA bacteremi...