Stachylysin May Be a Cause of Hemorrhaging in Humans Exposed to Stachybotrys chartarum

Abstract

Stachybotrys chartarum is a toxigenic fungus that has been associated with human health concerns such as nasal bleeding in adults and pulmonary hemosiderosis (PH) in infants. Seven of eight strains of S. chartarum isolated from homes of infants with PH in Cleveland, Ohio, and the strain from the lung of an infant with PH in Texas produced stachylysin in tryptic soy broth (TSB), whereas only one out of eight strains isolated from control homes produced stachylysin. However, all strains produced stachylysin when grown on TSB with 0.7% sheep's blood. When stachylysin was injected into Lumbricus terrestis, the erythrocruorin hemoglobin (absorbance peaks at 280 and 415 nm) was released, resulting in a lethal effect. These results support the hypothesis that stachylysin may be one agent responsible for hemorrhaging in humans.Pulmonary hemosiderosis (PH) in infants has been associated with exposure to Stachybotrys chartarum (Ehrenb. ex Link) Hughes(ϭ S. atra Corda) in some studies (9,12,13). PH is characterized by a chronic bleeding which leads to the observation of hemosiderin-laden macrophages in the infant lungs and can be fatal (4, 5). Agricultural workers exposed to S. chartarum report nasal and tracheal bleeding (17, 31).Consumption of S. chartarum by domestic or experimental animals can be lethal (15, 28). Generally, low-molecularweight toxins, e.g., macrocyclic trichothecenes, are considered to be responsible for the lethality (10). Hemorrhaging is not a typical response to purified trichothecenes in experimental animals (32), but it is known that consumption of S. chartarumcontaminated fodder by horses leads to hemorrhaging (14). Perhaps factors other than low-molecular-weight toxins are responsible for the hemorrhaging.High-molecular-weight cytotoxins, called hemolysins, are produced by both bacteria and fungi and can cause hemorrhaging. For example, ␤-hemolysin produced by the group B streptococci produce hemorrhages in infant lungs (16,22,23). Exposure of experimental animals to the purified hemolysin from Aspergillus fumigatus caused hemorrhagic lesions in experimental animals (27).Recently, the hemolysin from S. chartarum, designated stachylysin, was initially characterized (35,36,37). Strains of S. chartarum isolated from PH case houses in Cleveland, Ohio (18), and the isolate from the lung of a PH patient in Texas (9) generally produced significantly more hemolysin under the conditions tested than most strains isolated from control houses in Cleveland (36). In this report, an explanation for the hemorrhaging after S. chartarum exposure is suggested, based on the role of stachylysin in vascular leakage in a model organism, Lumbricus terrestis. MATERIALS AND METHODSStrains of Stachybotrys. Eight strains of S. chartarum isolated from PH control houses in Cleveland and eight strains from case houses (18) and the Houston strain (9) were used in this study. Stachylysin was purified from strain 58-06.Purification of stachylysin. Stachylysin was purified as previously described (37) with the following modificat...

Idiopathic pulmonary haemosiderosis revisited

“…A series of articles linking environmental exposure to fungi (especially Stachybotrys atra) in water-damaged houses in Cleveland, OH, USA and infantile pulmonary haemosiderosis led to an extensive investigation of possible infectious or mycotoxigenic pathogenesis [46][47][48][49][50][51][52][53][54][55][56][57][58]. The postulated mechanism is that fungal toxins called trichotecens, which are potent protein synthesis inhibitors, impede the angiogenesis underneath the rapidly forming alveolar membranes, making the acinar region prone to bleeding.…”

Possible Role of Fungal Hemolysins in Sick Building Syndrome

“…Stachylysin injected into the earthworm Lumbricus terrestis resulted in the leakage of hemoglobin from the animal's vascular system (Vesper and Vesper, 2002). We showed that stachylysin caused pores in sheep 200 VESPER AND VESPER RBC membranes (Vesper et al, 2001), but L. terrestis has no oxygencarrying cells and a closed vascular system.…”

“…Exposure to S. chartarum has been shown to cause hemorrhaging in animals (Forgacs, 1972;Sarkisov and Orshanskaiya, 1944) and agricultural workers (Hintikka, 1978;Rylander,1994;Sorenson and Lewis, 1996). The hemolysin stachylysin caused hemorrhaging in an animal model (Vesper and Vesper, 2002). Thus there are a number of cases where fungal hemolysins cause damage to or destruction of vascular tissues.…”

“…We showed that stachylysin caused pores in sheep 200 VESPER AND VESPER RBC membranes (Vesper et al, 2001), but L. terrestis has no oxygencarrying cells and a closed vascular system. The release of erythrocruorin hemoglobin from L. terrestis and the development of aneurism-like structures suggested that stachylysin caused cytolytic vascular leakage, resulting in an LD 50 of 1100 g/Kg in L. terrestis (Vesper and Vesper, 2002).…”

Health hazard evaluation report: HETA #2005-0126 and #2005-0138-3004, International Marine Terminal, Scotia Prince Cruises and Department of Homeland Security, U.S. Customs and Border Protection, Portland, Maine.

“…2,3 After incubation, the coated plates w ere washed three times with phosphate-buffered saline-0.05% Tween 20 (PBST, Sigma). Standards of 11 different concentrations of stachy lysin-BSA (0 to 62.5 ng/ml) diluted in 1: 20 diluted (PBST) commercially available human sera o r diluted (1:20 in PBS T) subject sera (in triplicate) were mixed with affinit y-purified rabbit antistachylysin IgG ( Bethyl Larboratories, Montgomery, TX) diluted 1:20,000 in PBST) in test tubes and incubated at 4°C for 2 4 hours.…”