Isolation Of Amoebae From The Air

Abstract

D U R I N G an investigation into the possibility of isolating respiratory syncytial virus from the environment (Kingston, 1969), hartmannellid amoebae were isolated from the air and from the surfaces in cubicles in which infants with acute bronchiolitis were being nursed. In the present study a more extensive investigation was carried out, partly because of the possibility that these amoebae may be associated with disease. METHODS Isolation of' the amoebaeTissue culture method. Standard virus cultivation techniques were used. In outline, the method was to suck air into the liquid contained in a special modification of the slit sampler (Lidwell, 1966) and then to inoculate as much as possible of the liquid on to HeLa cells. The cells were maintained on Gey's solution with 5 per cent. rabbit serum, 0.25 per cent. lactalbumin hydrolysate, and with 100 units each of penicillin and streptomycin and 5 pg Fungizone per ml. The cells were incubated at 33"-37"C, mean c. 35°C. This technique was used because virus isolation was the original object of the work. This approach has the disadvantage of being laborious, of requiring the cell sheet to be washed after an initial short period of incubation to prevent bacteria and fungi breaking through the antibiotic cover, with the risk of losing amoebae, and of requiring the use of a fungistatic agent, that used being Fungizone, which is toxic to some amoebae (personal communication from Dr C. G. Cu 1 bertson).Agar plate method. This method is based on that used by Singh (1952) for cultivation of small free-living amoebae from the soil. Oxoid Ionagar no. 2 was dissolved in glassdistilled water to give 1.5 per cent. water agar, which was poured into 5+ in. (14 cm) diameter petri dishes. When set, the plates were dried in the hot room for about 1 hr. Klebsiella aerogenes (NCTC9667) was inoculated into a 100-ml bottle of Oxoid nutrient broth no. 2, and after overnight incubation at 37°C the bacteria were harvested by centrifugation and resuspended in about 20 ml sterile distilled water. Three millilitres of this suspension was spread on to each water agar plate and allowed to adsorb. The plates were then used for air sampling either by exposing them for 10 min. in a 20 cu. ft (570 litre) per min. slit sampler or by leaving them open to the air for various periods up to 7 hr (" settle plates "). Unless otherwise stated, exposure was by the slit-sampler technique. In some preliminary experiments, not reported here, the klebsiella suspension was killed by heating for 2 hr at 56°C before being spread on to the plates, but this treatment was discontinued as heat-killed bacteria will not support the growth of some amoebae. The plates were incubated at 30"

Determination of Amoebicidal Activities of Multipurpose Contact Lens Solutions by Using a Most Probable Number Enumeration Technique

“…Organisms of this genus are commonly found inhabiting soil (8) and aquatic environments (9,23), but they have also been isolated from swimming pools (32), tap water (44,46), bottled mineral water (37), atmospheric samples (22), and even contact lens care solutions (47). The organisms' life cycle is composed of two distinct stages: a motile, metabolically active trophozoite stage in which the organism is capable of multiplication and is sensitive to noxious stimuli, and a dormant cyst stage, in which the organism is resistant to desiccation, disinfection, and extremes of temperature.…”

Isolamento de amebas de vida livre potencialmente patogênicas em poeira de hospitais

“…Assim, Kingston & Warhurst, 10 em 1969, isolaram essas amebas da poeira e do ar de um quarto ocupado por crianças acometidas de infecção respiratória.…”

The occurrence and distribution of pathogenic free‐living amoebae in thermal areas of the North Island of New Zealand

“…Isolations have been recorded from a variety of environments such as air (Kingston & Warhurst 1968), humidifier systems (United Kingdom M.R.C. Symposium 1977) and freshwater, brackish, and ocean sediments (De Jonckheere et al 1975;De Jonckheere & Van de Voorde 1977;Sawyer et al 1977;Stevens et al 1977;Wellings et al 1977).…”