Amebic meningoencephalitis caused by Balamuthia mandrillaris: case report and review.

Balamuthia mandrillaris, formerly referred to as a leptomyxid ameba, is a free-living ameba that has recently been identified as a cause of meningoencephalitis. Previously, only two genera, Naegleria and Acanthamoeba, were recognized as causes of central nervous system (CNS) infections in humans. In contrast to Naegleria, Balamuthia causes a subacute-to-chronic infection of the CNS.

Ultrastructural effects of lactoferrin binding on Giardia lamblia trophozoites.

Lactoferrin and its derived N-terminal peptide may be important host defenses against Giardia lamblia. We showed earlier that lactoferrin and the derived peptides have potent giardicidal activity in vitro. Using indirect immunofluorescence, we now demonstrate binding of lactoferrin and the peptides to the live trophozoite surface.

Giardicidal activity of lactoferrin and N-terminal peptides.

Human and bovine lactoferrins and their derived N-terminal peptides were giardicidal in vitro. Fe3+, but not Fe2+, protected trophozoites from both native lactoferrin and peptides, although the latter lack iron-binding sites. Other divalent metal ions protected only against native lactoferrin.

Killing of Giardia lamblia by cryptdins and cationic neutrophil peptides.

Antimicrobial polypeptides such as the defensins kill a wide range of organisms, including bacteria, fungi, viruses, and tumor cells. Because of the recent finding that intestinal defensins, also known as cryptdins, are synthesized by the Paneth cells of the small intestinal crypts and released into the lumen, we asked whether defensins and other small cationic antimicrobial peptides could kill the trophozoites of Giardia lamblia, which colonize the small intestine. Four mouse cryptdins, two neutrophil defensins (HNP-1 [human] and NP-2 [rabbit]), and the unique tryptophan-rich bovine neutrophil polypeptide indolicidin each had some antigiardial activity against trophozoites in vitro.