Analysis of an outbreak of non-phage-typeable methicillin-resistant Staphylococcus aureus by using a randomly amplified polymorphic DNA assay.

A cluster of methicillin-resistant Staphylococcus aureus (MRSA) infections among patients on an intensive care unit (ICU) was detected by routine infection control surveillance. In the period from 5 January to 22 June 1995, 10 patients on the ICU and a further 6 patients (5 on one ward that had received colonized patients transferred from the ICU) were affected by MRSA strains with the same antibiotic susceptibility patterns. Seven (44%) of these 16 colonized patients developed MRSA bacteremia.

Antibacterial action of ciprofloxacin.

The mechanisms by which quinolones rapidly kill are ill defined. We have investigated the action of ciprofloxacin on Escherichia coli KL16 with a combination of traditional and flow cytometric methods and have analyzed cells for changes in membrane potential, membrane integrity, oxidative metabolism, morphology, and viability. Log-phase cultures were exposed to various concentrations (0.

vanA genes in vancomycin-resistant clinical isolates of Oerskovia turbata and Arcanobacterium (Corynebacterium) haemolyticum.

We report the cloning and sequencing of vanA genes present in the high-level vancomycin- and teicoplanin-resistant clinical isolates Oerskovia turbata 892 and Arcanobacterium (Corynebacterium) haemolyticum 872. The presence of vanA was detected by Southern blotting and PCR and confirmed by DNA sequencing. vanA-like sequences were encoded on plasmids of 15 and 20 kb respectively.

Serological response to coagulase-negative staphylococci in patients with peritonitis on continuous ambulatory peritoneal dialysis.

Sera and dialysis effluent from 20 patients on continuous ambulatory peritoneal dialysis (CAPD) with coagulase-negative staphylococcal (CNS) peritonitis were examined by immunoblotting for antibody activity against CNS. Immunoblotting was highly sensitive and demonstrated significantly greater antibody activity in serum and dialysate of infected patients compared with that of uninfected CAPD patients or healthy volunteers. Fourteen of 20 infected CAPD patients had strong antibody activity (> 7 bands); one patient had equivocal activity.

Evaluation of methods for typing coagulase-negative staphylococci.

One hundred and forty-two coagulase-negative staphylococci (CNS) isolated from dialysate effluent or skin of patients receiving continuous ambulatory peritoneal dialysis (CAPD) were typed by extended antibiogram (16 antibiotics) and biotype (26 reactions). These isolates were then typed by supplementary methods to determine the most suitable typing method for an epidemiological study of antibiotic resistance. These included phage typing, reverse phage typing, plasmid typing, whole-cell protein typing by SDS-PAGE with analysis by densitometry, and immunoblotting.