Investigations into the survival of Pseudomonas aeruginosa in poloxamer-iodine

Abstract

Laboratory investigations were conducted to study potential mechanisms for prolonged survival of Pseudomonas aeruginosa in poloxamer-iodine (PxI). P. aeruginosa organisms isolated from PxI and adapted for growth in distilled water or found as part of a mixed microbial population from water in a manufacturing plant did not survive more than 15 s after challenge in stock PxI solution. Batches of PxI were compounded in the laboratory to determine the survival and growth of P. aeruginosa during the various stages of preparation. No P. aeruginosa organisms were recovered from the finished product at 1 min after the addition of iodine-iodide. However, we found P. aeruginosa in PxI 48 h after adding sterile PxI to the inside of a naturally contaminated polyvinyl chloride water distribution pipe. These organisms (10(4) CFU/ml) survived for as long as 98 days in contaminated stock PxI after it was removed from the polyvinyl chloride pipe. Both decreasing the free iodine level through addition of potassium iodide and increasing the free iodine level through dilution of the product resulted in an increased length of survival of P. aeruginosa in contaminated PxI solution. Comparative survival studies with pipes of different composition revealed that other materials may exert an effect similar to polyvinyl chloride. We concluded that polyvinyl chloride and perhaps other materials may play an important role in the survival of P. aeruginosa in iodophors and may be one source of resistant microbial populations when used in manufacturing plants which produce these antimicrobial solutions.

Comparison of chemical dehydration and critical point drying for the stabilization and visualization of aging biofilm present on interior surfaces of PVC distribution pipe

“…Water and product PVC distribution pipes from a manufacturing plant associated with an episode of intrinsic bacterial contamination of a commercial iodophor solution were used in this investigation (Anderson et al 1984). These pipes had been removed from the plant and stored in the laboratory with contaminated water for 10 years, without physically disturbing any biofilm present within the interior surfaces of the PVC pipes.…”

“…Each dilution (10-'-10-4) was mixed and 0.5 ml quantities removed from each dilution and separately added to the surface of Trypticase soy agar plates (BBL Microbiology Systems, Cockeysville, MD) with 5% sheep erythrocytes (TSAB). Test fractions were evenly spread over the TSAB surface with individual sterile bent-glass L-rods and allowed to dry, and the plates were incubated at 35-37°C for 48 h. Because of previous experience with this biofilm milieu (Anderson et al 1984) an incubation period of 48 h was used.…”

“…Growth of bacteria within the glycocalyx can allow bacteria to survive otherwise lethal concentrations of industrial biocides and hospital antiseptics (Costerton et al 1985;Vess et al 1993;Phillips et al 1994). Extracellular material containing embedded cells can form on interior distribution pipe surfaces and serve as a continuous reservoir for microbial contamination in process water and formulated product (Sutherland 1972 ;Anderson et al 1984;LeChevallier et al 1988). Because of these types of contamination problems, scanning electron microscopy has become an important tool in preparing and observing a variety of sample surfaces to study micro-organisms in their developed or natural state.…”

“…Biofilm evaluated and observed in this study was established biofilm. Samples used in this investigation originated from PVC pipes used in laboratory studies conducted 10 years earlier (Anderson et al 1984(Anderson et al , 1990a. After those studies were completed, the remaining PVC distribution pipes were allowed to sit at ambient temperature (25°C) with constant exposure to contaminated water.…”

Physiological aspects of disinfection resistance in Pseudomonas cepacia

“…It has also been suggested that chlorineresistant bacteria may arise as a result of chlorination (Farkas-Himsley 1964;Ridgway and Olson 1982;Leyval et al 1984), although other investigators found no evidence for this (Haas and Morrison 1981). Iodine-resistant bacteria have been isolated from various sources including swimming pools (Favero and Drake 1966), iodophor disinfectant solutions (Berkelman et al 1981;Anderson et al 1984) and iodinated water on National Aeronautics and Space Administration (NASA) space shuttle orbiters (Pyle and McFeters 1989).…”