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Biomedical subjects

S Kilvington

Publications and source records attributed to S Kilvington.

27 records · Page 2Linked to original sources
PubMed1990

Survival of Legionella pneumophila within cysts of Acanthamoeba polyphaga following chlorine exposure.

The association between Legionella pneumophila and the free-living amoeba Acanthamoeba polyphaga was studied. Intracellular growth of L. pneumophila within amoebic trophozoite was confirmed by kinetic growth experiments, light and electron microscopy. Cysts produced from infected trophozoites were found to protect the legionellas from at least 50 mg/l free chlorine. The ability of L. pneumophila to survive within the cysts of A. polyphaga is suggested as a possible mechanism by which the organism evades disinfection and spreads to colonize new environments.

Acanthamoeba↗
PubMed1990

Laboratory investigation of Acanthamoeba keratitis.

Following the diagnosis of Acanthamoeba keratitis in a contact lens wearer, the antimicrobial susceptibility of the clinical isolate and the environmental source of the infection were investigated. Contrary to previous reports, in vitro antimicrobial testing showed that the infecting strain was inherently resistant to propamidine isethionate. Restriction endonuclease digestion analysis of Acanthamoeba whole-cell DNA of strains isolated from the patient's cornea, contact lens storage container, saline rinsing solution, and kitchen cold-water tap showed that the isolates were identical. This implicates, for the first time, domestic tap water as the source of Acanthamoeba sp. in this infection. It is therefore recommended that the use of homemade saline solutions and the rinsing of contact lenses in tap water be strongly discouraged.

Acanthamoeba↗
PubMed1990

Contamination of contact lens storage cases by Acanthamoeba and bacteria.

In order to identify possible risk factors for microbial keratitis the storage cases for contact lenses of 102 asymptomatic lens wearers were tested for contamination by bacteria and free-living amoebae. Of this group 43 had significant counts of viable bacteria and only 40 had negligible counts. Seven had contamination by acanthamoebae, of whom six also had significant bacterial counts. These results were categorised according to the type of contact lens worn and the lens disinfection method. The high rates of contamination by apathogenic and pathogenic organisms, in particular Acanthamoeba, and the probable support by contaminating bacteria of Acanthamoeba, are discussed.

Acanthamoeba↗
PubMed1986

Identification of Naegleria fowleri in fresh isolates of environmental amoebae using a staphylococcal coagglutination technique.

A coagglutination test using Staphylococcus aureus Cowan strain 1 sensitized with specific antiserum successfully identified Naegleria fowleri in axenic and monoxenic culture by detection of a heat stable antigen released into the culture medium during growth. Strong coagglutination, visible to the naked eye, occurred within 30 sec when the sensitized reagent was mixed on a slide with medium from N. fowleri cultures. N. lovaniensis gave a weak cross-reaction which developed over one min clearly distinguishable from that of N.fowleri.N.gruberi and N. australiensis gave no reaction. The technique is proposed as part of a rapid and economical scheme for detecting N. fowleri in environmental samples very soon after primary isolation, with distinct advantages over conventional methods. Further development of the technique to detect other Naegleria spp. and the early diagnosis of primary amoebic meningoencephalitis are suggested as future applications.

Agglutination Tests↗
PubMed1985

Rapid identification of thermophilic Naegleria, including Naegleria fowleri using API ZYM system.

The suitability of the API ZYM system for identifying thermophilic Naegleria species, based on enzyme presence and activity, was investigated. Replicate testing on strains of N fowleri, N lovaniensis, and N australiensis cultured in a monoxenic and an axenic medium showed that the system could provide a rapid and reproducible means of identifying the species soon after primary isolation. No single enzyme was found specific for any one species, but considerable differences were found in the patterns of activity of acid phosphatase and leucine arylamidase. When these were compared the species could be differentiated. Use of the system in conjunction with a simple culture method is proposed as a readily available means of monitoring environmental and public bathing sites to prevent primary amoebic meningoencephalitis.

Acid Phosphatase↗