High-throughput screening for antimicrobial compounds using a 96-well format bacterial motility absorbance assay.

There is a pressing need to develop new antimicrobial drugs because of the increasing resistance of pathogenic bacteria to existing antibiotics. The preliminary development and validation of a novel methodology for the high-throughput screening of antimicrobial compounds and inhibitors of bacterial motility is described. This method uses a bacterial motility swarming agar assay, combined with the use of offset inoculation of the wells in a standard, clear, 96-well plate, to enable rapid screening of compounds for potential antibiotic and antimotility properties with a standard absorbance microplate reader. Thus, the methodology should be compatible with 96-well laboratory automation technology used in drug discovery and chemical biology studies. To validate the screening method, the Genesis Plus structurally diverse library of 960 biologically active compounds was screened against a motile strain of the gram-negative bacterial pathogen Salmonella typhimurium. The average Z' value for the positive and negative motility controls on all 12 compound plates was 0.67 +/- 0.14, and the signal-to-baseline ratio calculated from the positive and negative controls was 5.9 +/- 1.1. A collection of 70 compounds with well-known antimicrobial properties was successfully identified using this assay.

Effect of epidural clonidine added to epidural sufentanil for labor pain management.

Labor analgesia with intrathecal sufentanil has been shown to be prolonged by the addition of intrathecal clonidine. The current study was designed to determine if epidural clonidine would prolong labor analgesia provided by epidural sufentanil. Forty laboring primiparous women at less than 5 cm cervical dilation requesting epidural analgesia were enrolled. Following a 3 mL test dose of lidocaine with epinephrine, patients were randomized to receive 10 mL of either sufentanil 20 microg (S) or sufentanil 20 microg with clonidine 75 microg (SC). After administration of the analgesic, pain scores and side-effects were recorded for each patient at 5, 10, 15, 20 and 30 min, and every 30 min thereafter, by an observer blinded to the technique used. There were no demographic differences between the two groups. Pain relief was rapid for all patients. The mean duration of analgesia was similar between the S group (153 +/- 78 min) and the SC group (178 +/- 55 min). Side-effects were similar between the two groups. There was no difference between the two groups in time from sufentanil administration to delivery, incidence of operative or assisted delivery, or cervical dilation at the time of redose. For early laboring patients, epidural sufentanil 20 microg after a lidocaine test dose provides analgesia comparable to that of sufentanil 20 microg with clonidine 75 microg; there was no significant difference in analgesic duration between the two groups.