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Acanthamoeba keratitis due to a genus of free-living amoebae is a severe corneal infection. Treatment of this disease is based on the combined use of antiseptics and other drugs, including azoles. We tested isavuconazole, the latest marketed azole, in vitro, against A. castellanii, A. lenticulata and A. hatchetti. Our results show that isavuconazole presents slight amoebistatic activity against A. castellanii trophozoites but no cysticidal activity. Isavuconazole could be used only in association for management of AK due to A. castellanii., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Acinetobacter baumanii, which may be found in water, is an important emerging hospital-acquired pathogen. Free-living amoebae can be recovered from the same water networks, and it has been shown that these protozoa may support the growth of other bacteria. In this paper, we have studied potential relationships between A. baumanii and Acanthamoeba species. Two strains of A. baumanii isolated from hospital water were co-cultivated with the trophozoites or supernatants of two free-living amoebae strains: Acanthamoeba castellanii or Acanthamoeba culbertsoni. Firstly, the presence of the amoebae or their supernatants induced a major increase in A. baumanii growth, compared with controls. Secondly, A. baumanii affected only the viability of A. culbertsonii, with no effect on A. castellanii. Electron microscopy observations of the cultures investigating the bacterial location in the protozoa showed persistence of the bacteria within cyst wall even after 60 days of incubation. In our study, the survival and growth of A. baumanii could be favored by Acanthamoeba strains. Special attention should consequently be paid to the presence of free-living amoebae in hospital water systems, which can promote A. baumanii persistence., (© 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.)

Campylobacter jejuni is a recognized and common gastrointestinal pathogen in most parts of the world. Human infections are often food borne, and the bacterium is frequent among poultry and other food animals. However, much less is known about the epidemiology of C. jejuni in the environment and what mechanisms the bacterium depends on to tolerate low pH. The sensitive nature of C. jejuni stands in contrast to the fact that it is difficult to eradicate from poultry production, and even more contradictory is the fact that the bacterium is able to survive the acidic passage through the human stomach. Here we expand the knowledge on C. jejuni acid tolerance by looking at protozoa as a potential epidemiological pathway of infection. Our results showed that when C. jejuni cells were coincubated with Acanthamoeba polyphaga in acidified phosphate-buffered saline (PBS) or tap water, the bacteria could tolerate pHs far below those in their normal range, even surviving at pH 4 for 20 h and at pH 2 for 5 h. Interestingly, moderately acidic conditions (pH 4 and 5) were shown to trigger C. jejuni motility as well as to increase adhesion/internalization of bacteria into A. polyphaga. Taken together, the results suggest that protozoa may act as protective hosts against harsh conditions and might be a potential risk factor for C. jejuni infections. These findings may be important for our understanding of C. jejuni passage through the gastrointestinal tract and for hygiene practices used in poultry settings.

We present a novel and simple technique for storing live Acanthamoeba for long periods of time. The amoebae are maintained at refrigerator temperatures in a peptone-yeast extract-glucose (PYG) medium normally used for cultivation. Using this method, we obtained survival rates of at least 4 years for Acanthamoeba polyphaga and 3 years for Acanthamoeba castellanii and Acanthamoeba rhysodes. Advantages of this storage method are: (1) it is quick and simple, (2) inexpensive, (3) does not require encystment before storage, (4) resuscitation of cysts can be achieved within a week of culture in PYG medium at 27 degrees C, and does not require co-culture with bacteria or any special equipment.

Purpose: To determine the effect of a multipurpose contact lens solution (ReNu MultiPlus Multi-Purpose Solution [RMP]) on the relative survival and binding of trophozoites and cysts of Acanthamoeba on hydrogel lenses with a no-rub regimen., Methods: A stand-alone test procedure with RMP was conducted with and without the presence of organic soil (1 x 10(7) colony-forming units/mL heat-killed cells of Saccharomyces cerevisiae in heat-inactivated fetal bovine serum). Survival of amoebae on hydrogel contact lenses exposed to RMP was determined with a no-rub care regimen., Results: ReNu MultiPlus Multi-Purpose Solution reduced the number of recoverable amoebae by more than 95% within 4 hours of inocula of 10(5) trophozoites and cysts, regardless of the presence or absence of an organic soil. Amoebae, particularly cysts, were readily rinsed from contact lenses, including silicone hydrogels, without rubbing after exposure to RMP., Conclusions: The efficacy of RMP for Acanthamoeba was not appreciably altered in the presence of organic soil in a no-rub protocol. The antimicrobial activity, in part, appeared to be a combination of reducing the capacity for binding of representative Acanthamoeba to the lens by alteration of morphology, often followed by lysis of the amoebae.