Fifteen different isolates of Pseudomonas aeruginosa were used to study the kinetics of adhesion to 304 and 316-L stainless steel. Stainless steel plates were incubated with approximately 1.5 x 107 CFU/ml in 0.01 M phosphate-buffered saline (pH 7.4). After the plates were rinsed with the buffer, the number of adhering bacteria was determined by a bioluminescence assay. Measurable adhesion, even to the electropolished surfaces, occurred within 30 s. Bacterial cell surface hydrophobicity, as determined by the bacterial adherence to hydrocarbons test and the contact angle measurement test, was the major parameter influencing the adhesion rate constant for the first 30 min of adhesion. A parabolic relationship between the CAM values and the logarithm of the adhesion rate constants (In k) was established. No correlation between either the salt aggregation or the improved salt aggregation values and the bacterial adhesion rate constants could be found. Since there was no significant correlation between the bacterial electrophoretic mobilities and the In k values, the bacterial cell surface charge seemed of minor importance in the process of adhesion of P. aeruginosa to 304 and 316-L stainless steel.

We describe a cluster of four septicemias with pseudomonas, that occurred in a unit performing formaldehyde reuse of capillary dialyzers. Samples of blood, heparin solutions, dialysate and effluent of reused dialyzers, were evaluated bacteriologically and upon the adequacy of the reuse procedure. Pseudomonas aeruginosa, vesicularis and/or xanthomonas maltophilia were found on the blood cultures obtained during the septicemic reactions, and in the effluent of two reprocessed dialyzers not yet used (greater than 10(4) CFU/ml). These two dialyzers had also extremely low formaldehyde concentrations (0.0014 and 0.005% versus the expected 4%). Membrane and antibiogram characteristics of a Pseudomonas aeruginosa strain, recovered from the blood cultures in one patient, and of a strain found in the effluent of one of the two contaminated reprocessed dialyzers, were the same. The problem was attributed to the inadequate mixing of the disinfectant with the tap water used in the automated reprocessing device, in the absence of an alarm disclosing this failure.

A thorough validation of the bacterial adherence to hydrocarbons (BATH) test was performed by means of a bioluminescence assay. Ten different gram-negative strains were subjected to the BATH test. For the calculation of the adhesion index, several factors had to be taken into account: ATP leakage, the action of ATP-hydrolyzing enzymes, the change in the extraction efficiency of Nucleotide-Releasing Reagent for Microbial Cells (NRB; Lumac bv) after vortexing and the difference in light production after the addition of NRB. When the adhesion index values obtained by bioluminescence measurement were used as reference, the total plate count technique appeared to be unreliable in estimating the number of bacteria adhering to the hydrocarbon phase. A highly significant correlation was established, however, between those reference values and the adhesion index values obtained by the optical density reading for octane and especially for hexadecane. With xylene, no correlation was found between the optical density reading values and the total plate count or bioluminescence values.

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Tissue and plasma concentrations were determined after intravenous and oral administration of erythromycin to pigeons to establish the pharmacokinetics and bioavailability of the drug. A short mean half-life of elimination of 0.9 h was found. The relative bioavailability after direct crop administration of erythromycin thiocyanate or erythromycin ethylsuccinate at a dosage rate of 100 mg/kg was less than 10%. At a drug concentration in drinking water of 1 g/l, erythromycin plasma levels were barely detectable, whilst lung and trachea concentrations reached a maximum of 1.6 micrograms/ml. Even after crop administration of 100-mg/kg erythromycin thiocyanate, low plasma levels were obtained, whilst lung and trachea concentrations were substantially higher. Prescribed drinking-water regimens seemed unable to yield therapeutic tissue concentrations. Only individual crop administration seemed an appropriate medication method. The use of erythromycin ethylsuccinate did not present any advantage in comparison with erythromycin thiocyanate.