James C. Feeley

Intracellular multiplication ofLegionella pneumophila in amoebae isolated from hospital hot water tanks

We studied the ability ofLegionella to multiply in potable water samples obtained from investigations of nosocomial legionellosis. AutochthonousLegionella multiplied in three of 14 hospital water samples after incubation at 35°C and 42°C. All three samples were from hot water tanks. Multiplication did not occur when a selected sample was filtered through a 0.45-μm membrane and reinoculated with indigenousLegionella. We isolated bothLegionella pneumophila and one or more species of free-living amoebae, primarity members of theHartmannellidae, from each of these hot water tank samples. Amoebae from a total of six hot water tank samples were used for cocultivation studies withL. pneumophila. All amoebae supported multiplication ofLegionella in coculture at 35°C. Four of six isolates of amoebae supported multiplication oflegionella at 42°C, while none supported multiplication at 45°C. Gimenez staining and electron microscopy showed thatLegionella multiplied intracellularly in amoebae. Control of these amoebae in potable water may prevent colonization and multiplication ofLegionella in domestic hot water systems.

Ten New Species of Legionella

Ten new Legionella species were characterized on the basis of biochemical reactions, antigens, cellular fatty acids, isoprenoid quinones, and deoxyribonucleic acid relatedness. Nine of the new species were isolated from the environment, and one, Legionella hackeliae, was isolated from a bronchial biopsy specimen obtained from a patient with pneumonia. The species all exhibited the following biochemical reactions typical of the legionellae: growth on buffered cysteine-yeast extract agar, but not on blood agar; growth requirement for cysteine; gram negative; nitrate negative; urease negative; nonfermentative; catalase positive; production of a brown pigment on tyrosine-containing yeast extract agar; liquefaction of gelatin; and motility. Legionella spiritensis was weakly positive for hydrolysis of hippurate; the other species were hippurate negative. Legionella cherrii, Legionella steigerwaltii, and Legionella parisiensis exhibited bluish white autofluorescence. Legionella rubrilucens and Legionella erythra exhibited red autofluorescence. The other species, L. spiritensis, L. hackeliae, Legionella maceachernii, Legionella jamestowniensis, and Legionella santicrucis did not autofluoresce bluish white or red. All species had cellular fatty acid contents qualitatively similar to those of previously described legionellae and had major amounts of ubiquinones with more than 10 isoprene units in the side chains. Each new species was serologically distinct from previously described Legionella species. As determined by the hydroxyapatite method at 60°C, two strains of L. maceachernii were 100% related, and four strains of L. cherrii were 94 to 99% related. The other new species were represented by single strains. The levels of relatedness of the new species to each other and to previously described legionellae ranged from 1 to 67%. L. maceachernii, L. jamestowniensis, and L. hackeliae were less than 25% related to other species. L. rubrilucens and L. erythra, and two red-autofluorescing species, were about 60% interrelated. L. spiritensis (a non-autofluorescing species) was 34% related to L. rubrilucens. L. santicrucis was 64% related to Legionella sainthelensi. The three bluish white-autofluorescing species, L. parisiensis, L. cherrii, and L. steigerwaltii, were most closely related to other bluish white-autofluorescing species, especially Legionella bozemanii, Legionella dumoffii, Legionella gormanii, and “Legionella anisa” (35 to 67%).

Neonatal listeriosis: Distribution of serotypes in relation to age at onset of disease

SINCE THE ORIGINAL DESCRIPTION of neonatal listeriosis by Burn, 1 considerable information has accumulated regarding the causative organism; it has become clear that two distinct clinical gyndromes are seen in neonates: an early septicemic form and a delayed meningitic form. 2-7 Nevertheless an understanding of the epidemiology and pathogenesis of this disease is far from complete. Recent studies of group B streptococcal infections in infants have led to the association of certain serotypes with the clinical syndromes of early and late onset.S, 9 This report concerns the distribution of serotypes of Listeria monocytogenes isolated from 40 infants with neonatal listeriosis.

Viability ofLegionella pneumophila in choline-free water at elevated temperatures

Sterilization values were determined forLegionella pneumophila in chlorine-free, chlorine-demand-free water at elevated temperatures. These values were calculated from experimentally determined D values of 2500 min, 380 min, 13.93 min, 0.74 min, and 0.45 min at 45°C, 50°C, 55°C, 60°C, and 66°C, respectively. D values, Z value and temperature coefficient do not indicate unusual thermal resistance. Sterilization values, the minimum time required to eliminate an aquatic population ofL. pneumophila at a given test temperature, indicate that temperatures greater than about 65°C may not be necessary for efficient disinfection of potable quality water. These values and monitoring of time and temperature parameters can help predict the efficacy of in situ heat treatment of potable quality waters harboringL. pneumophila.

In-Vitro Studies of Interactions Between Tampons and Staphylococcus aureus

In-vitro studies were done to investigate the role of tampons and Staphylococcus aureus in toxic shock syndrome. Tampons did not enhance the growth of S. aureus in nutrient broth or human blood. Intrinsic contamination of tampons with S. aureus was not found among the 504 tampons cultured (95% confidence limits of fraction contaminated; 0 to 0.007). Toxin-producing S. aureus persisted significantly longer on artificially contaminated Rely tampons (Procter & Gamble) than on the other brands tested. The proportion of clinical isolates of S. aureus capable of producing toxin increased from two of 36 in 1960 to eight of 20 in 1979 (p = 0.002, Fishers exact test). This general increase in the proportion of toxin-producing strains may partially explain the increase in cases of toxic shock syndrome in recent years.

Isolation of Yersinia enterocolitica From Water

Only in the last few years has Yersinia enterocolitica been recognized as an etiologic agent. An increasing awareness of this organism is evidenced by the number of recorded cases and isolations each year from a variety of sources throughout the world. Previous failure to isolate Y. enterocolitica may be related to lack of familiarity rather than absence of the organism. Presence in the animate and inanimate environments does provide opportunity for transmission by person to person, animals, foodstuffs, and water, but vehicles of disease transmission are not fully delineated. General hygienic techniques in regard to food and water sanitation should apply in the methods for controlling the disease caused by Y. enterocolitica. The bacteriology of Y. enterocolitica is reviewed and laboratory methodology is described.