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Damage to human neurological system cells resulting from exposure to mycotoxins confirms a previously controversial public health threat for occupants of water-damaged buildings. Leading scientific organizations disagree about the ability of inhaled mycotoxins in the indoor environment to cause adverse human health effects. Damage to the neurological system can result from exposure to trichothecene mycotoxins in the indoor environment. This study demonstrates that neurological system cell damage can occur from satratoxin H exposure to neurological cells at exposure levels that can be found in water-damaged buildings contaminated with fungal growth. The constant activation of inflammatory and apoptotic pathways at low levels of exposure in human brain capillary endothelial cells, astrocytes, and neural progenitor cells may amplify devastation to neurological tissues and lead to neurological system cell damage from indirect events triggered by the presence of trichothecenes.

Buildings with poor indoor air quality (IAQ) frequently have many areas with surface fungal contamination. Studies have demonstrated that certain fungal genera (e.g., Cladosporium, Penicillium, and Stachybotrys) are able to grow on building materials such as wallpaper, drywall, and ceiling tiles, particularly after water damage has occurred. Due to the increasing awareness of sick building syndrome (SBS), it has become essential to identify building materials that prevent the interior growth of fungi. The objective of this study was to identify building materials that would not support the growth of certain fungal genera, regardless of whether an external food source was made available. The growth of three fungal genera (Cladosporium, Penicillium, and Stachybotrys) was evaluated on cellulose-containing ceiling tile (CCT) and inorganic ceiling tile (ICT). Both types of ceiling tile were exposed to environmental conditions which can occur inside a building. Our results show that ICT did not support the growth of these three fungal genera while CCT did. Our data demonstrate that ICT could serve as an ideal replacement for CCT.

Pasteurella haemolytica (Ph) is the most important cause of the bovine acute fibrinohemorrhagic pneumonia that occurs in market stressed calves after shipment to feedyards. Recent characterization of neuraminidase production by these organisms has shown that all 16 serotypes produce an immunologically similar form of the enzyme. Anti-neuraminidase antibody against PhA1 and PhA6 was determined in 101 2- to 5-month-old calves, on their farms of origin, at the order buyer barn (OBB), and through 28 days in the feedyard. Half of the calves were vaccinated with a killed Ph serotype-A1 (PhA1) product. Nasal secretion and tonsil wash specimens were cultured for Ph and Pasteurella multocida (Pm). Serum antibody against PhA1 and PhA6 was measured by indirect hemagglutination (IHA), and anti-neuraminidase antibody was determined by the neutralization assay. At the feedyard, 73 calves had respiratory tract disease. IHA values ranged between 1:2 and 1:1024 for PhA1 and between 1:2 and 1:512 for Ph serotype A6 (PhA6). Forty-two, 24, and 28% of the calves were infected with PhA1, PhA6, and Pm, respectively. Ninety-six percent of the calves experienced an increase in anti-PhA1 neuraminidase antibody when sera drawn on feedyard day 28 were compared with sera drawn on the farm. These data demonstrate that the enzyme neuraminidase is produced in vivo in market stressed cattle after a natural Ph infection.

Cross-protection studies employing three serotypes of Pasteurella haemolytica (Ph) were performed in goats, with challenge exposure by transthoracic injection. Indirect hemagglutination (IHA) serum titers showed that the herd had been naturally infected with Ph biovar A, serovar 2 (PhA2) prior to the study. Sixty-four weanling male Spanish goats were randomly allotted to 16 groups. Fifteen goats were given two transthoracic injections into the lungs 21 days apart with live Pasteurella haemolytica biovar A, serovar 1 (PhA1) in agar beads. Fifteen goats were given two transthoracic injections into the lungs 21 days apart with live PhA2 in agar beads. Sixteen goats were given two transthoracic injections into the lungs 21 days apart with live P. haemolytica biovar A, serovar 6 (PhA6) in agar beads. Eighteen control (CON) goats were given two transthoracic injections into the lungs 21 days apart with agar beads alone. Fourteen days after the second injection, goats were challenge-exposed to either live PhA1, PhA2, or PhA6 by transthoracic injection into the lung, and 4 days later, all goats were euthanatized and necropsied. Serum antibody to P. haemolytica antigens was measured throughout the experiment. Mean volumes of consolidated lung tissue for the CON goats challenged with PhA1, PhA2, and PhA6 were 28.29 cm3, 8.36 cm3, and 16.29 cm3, respectively. Mean volumes of consolidated lung tissue for the PhA1-immunized goats challenged with PhA1, PhA2, and PhA6 were 4.38 cm3, 0.25 cm3, and 1.90 cm3, respectively. Mean volumes of consolidated lung tissue for the PhA2-immunized goats challenged with PhA1, PhA2, and PhA6 were 9.68 cm3, 0.05 cm3, and 3.39 cm3, respectively. Mean volumes of consolidated lung tissue for the PhA6-immunized goats challenged with PhA1, PhA2, and PhA6 were 14.05 cm3, 1.27 cm3, and 4.53 cm3, respectively. These data demonstrate protection in immunized goats challenged with the homologous serotype of P. haemolytica. PhA1-immunized animals were protected against serotype 2 challenge as well as against serotype 6 challenge. PhA2-immunized animals were not protected against serotype 1 challenge, but were protected against transthoracic PhA6 challenge. PhA6-immunized animals were not protected against serotype 1 challenge, but were protected against transthoracic PhA2 challenge. There appears to be some cross-protection among the P. haemolytica serotypes, and this fact should be taken into consideration when developing vaccines against this organism.

Ninety-one isolates of Pasteurella multocida (Pm) and 124 of Pasteurella haemolytica (Ph) were recovered from the lungs of calves that died of bovine respiratory tract disease (BRTD). Nine Pm enzyme profiles (A through I) and 9 Ph enzyme profiles (J through R) were determined for the Pasteurella isolates. The Pm isolates were relatively evenly divided among the enzyme profiles, with one exception, profile I. The Ph isolates were not evenly distributed among the profiles. Fifty of the 91 Pm isolates were serotyped. Forty-two Pm isolates were positive for capsule type A, and 8 were untypable. Five somatic type antigen profiles (3; 3,4; 3,7; 3,4,7; and 4) were identified among the 50 serotyped Pm isolates; one isolate was untypable. The Ph isolates were further divided through serotyping and grouped as follows: 74 (60%) Pasteurella haemolytica A1 (PhA1), 12 (10%) PhA2, 4 (3%) PhA5, and 34 (27%) PhA6. Eighty-one percent of the Ph serotypes were clustered in the M and N enzyme profile. The P enzyme profile was almost unique to PhA2 (8 of 12, 67% of PhA2 isolates). Results of this study indicate a need to collect more data on Ph serotypes at the state veterinary diagnostic laboratories.

A total of 721 field isolates of various Pasteurella species (haemolytica, multocida, and testudinis) from various regions of the United States were examined for extracellular neuraminidase production. All strains were grown and tested in the same way. Included were 372 P. haemolytica serotype 1 isolates, 181 P. haemolytica serotype 2 isolates, 63 P. haemolytica serotype 6 isolates, 101 Pasteurella multocida isolates, and 4 Pasteurella testudinis isolates. All Pasteurella species examined produced the enzyme. The data revealed the following: (1) Several transfers of P. haemolytica strains on blood agar medium did not cause a decrease in enzyme activity. (2) P. haemolytica serotypes 2 and 6 produce more neuraminidase than P. haemolytica serotype 1, P. multocida, and P. testudinis isolates. (3) There was no apparent change in neuraminidase production by P. haemolytica serotypes 1 and 2 obtained from the same animal taken on different days in the feedyard. (4) There was no significant change in neuraminidase production by P. haemolytica serotype 2 isolates taken from the same animal at the auction market and later at the feedyard.

Monoclonal antibodies against germ-tube specific antigens ofCandida albicans were produced by a selective immunization protocol. The monoclonal antibody (MAb) DC3:H10 recognized a determinant preferentially expressed by germ tubes of the fungus compared to yeast cells. The MAb DC3:H10 antigen was expressed by nearly all germ tubes of the strains 3153A and B311. It was also expressed by germ tubes of the white phenotype of strain WO-1, and by many exponentially growing yeast cells of the opaque phenotype of this strain. The determinant appeared very rapidly after induction of germ tubes of strain 3153A. The MAb DC3:H10 epitope was sensitive to proteolytic treatment but not to periodate treatment, indicating its protein nature. The reactive material could be extracted from intact germ tubes by treatment with β-mercaptoethanol. On elution from a G-200 Sephadex column it yielded an apparent molecular weight of 519 kDa. This fraction appeared heterogeneous since at least two major bands of lower molecular weight were detected by silver staining following electrophoretic separation under denaturing conditions.

Nanogram quantities of a 25-kDa lipase purified from culture supernatants of Pseudomonas cepacia 90ee, a sputum isolate from a cystic fibrosis (CF) patient, were placed in the lungs of healthy rats. The resulting pathological changes included large amounts of proteinaceous exudate, the accumulation of polymorphonuclear leukocytes and red blood cells, and disorganization of alveolar structure. Pseudomonas cepacia 90ee immobilized in agar beads was also placed in the lungs of rats in a model of chronic infection. This resulted in bronchopneumonia and a milder inflammatory response than that elicited by the purified enzyme.

The adult mouse model was employed to examine the mechanism of virulence enhancement by the extracellular type-specific antigen (ETSA) of type-IIIStreptococcus agalactiae. Intraperitoneal injection of ETSA along with the infecting strain lowered the LD50 value forS. agalactiae and allowed for a more rapid proliferation of the organisms as opposed to that caused by the presence of a nonspecific dextran. The ETSA did not hinder recruitment of peritoneal exudate cells (PEC) into the peritoneal cavity as has been shown with capsular antigens of other bacteria. Chemiluminescent responses of mouse resident PEC demonstrated that these cells could render a respiratory burst when exposed to type-IIIS. agalactiae in the absence of complement and/or type-specific antibody. If the mouse PEC were exposed to ETSA before phagocytosis was attempted, however, ingestion of the type-III group-B streptococci was reduced. ETSA did not affect the viability of the PEC as determined by trypan blue exclusion. These results indicate that the ETSA can affect mouse PEC in an unidentified manner, thus rendering them less capable of ingesting and/or kiling type-IIIS. agalactiae.

Six strains of type IIIStreptococcus agalactiae isolated from milk samples from cases of bovine mastitis were examined for in vitro production of three potential extracellular virulence factors: neuraminidase, protease, and extracellular type-specific antigen. Virulence in mice, expressed as LD50 values, was examined for these six strains to determine if a relationship existed between the in vitro production of any of the three extracellular products and mouse lethality. Only in vitro production of extracellular type-specific antigen showed a correlation with virulence of these organisms in the mouse model. All six bovine strains were relatively avirulent in the mouse while producing reduced levels in vitro of extracellular typespecific antigen as compared to nine human isolates. The bovineS. agalactiae strains were an average of 538-fold less virulent for the mouse than were the high type-specific antigen producers isolated from human sources.

A type-III group-B streptococcus (Streptococcus agalactiae) isolated from a case of late-onset sepsis was examined for protease production. In broth culture, extracellular proteolytic enzymes were not detected until the late exponential phase of growth with maximal protease production occurring during the stationary phase. Three distinct protease pools were isolated from the supernatant fluids of stationary-phase cultures, employing a combination of ion-exchange chromatography and gel-filtration chromatography. One population of proteases (containing two protease pools separable by gel filtration chromatography) eluted from a diethylaminoethyl cellulose column at a sodium chloride gradient concentration of 0.15M while a second population eluted from the same material at a sodium chloride concentration of 0.35M. These protease pools varied in molecular weights from approximately 25,000 daltons to 160,000 daltons as determined by gel filtration on Sephadex G-200. All three protease preparations had pH optima of 8.0–9.0, and all were active against gelatin, human serum albumin, and casein, but were not active against elastin or collagen. In addition, all three protease preparations completely inactivated purified type-III group-B streptococal neuraminidase. The role of these proteases in the disease process caused by the type-III group-B streptococci must remain speculative at this time.

Various human isolates of type III group B streptococci (GBS) orStreptococcus agalactiae could be divided into two distinct groups (high and low producers) on the basis of their in vitro production of extracellular type-specific antigen (ETSA). The high ETSA producers were shown to be significantly more virulent in mice than were the low producers. In an effort to examine the possibility that purified extracellular products (ETSA, neuraminidase, or protease_ had a significant effect on GBS virulence in the mouse model, mice received either 1.0 ml of organisms intraperitoneally (IP) or 1.0 ml of organisms IP plus 0.1 ml IP of the appropriate purified extracellular products. Only purified ETSA demonstrated a substantial decrease (1.0 log10) in the 50% lethal dose (LD50) values and only for a high ETSA producing strain. Serum from mice infected with a high ETSA producer contained approximately 12.5 μg/ml of the ETSA, whereas serum from mice infected with a low ETSA producer contained no detectable ETSA. These data imply that the two different types of organisms (high and low ETSA producers) have somewhat different mechanisms of pathogenicity in the mouse model.

A group C streptococcus (Streptococcus zooepidemicus), isolated from the blood of a 79-year-old man who succumbed to infection, was examined for animal virulence, reactivity in an in vitro phagocytic assay, and the production of antiphagocytic structures. Initial examination of the clinical isolate by electron microscopy revealed the presence of high-density (HDC) and low-density (LDC) capsule variants. The HDC variant capsular material could be removed from the cell wall by hot acid extraction or obtained from the supernatant fluids when the organisms were grown in a defined medium. The capsular material was purified by ion-exchange chromatography on diethylaminoethyl cellulose and gel filtration on Sepharose 4B and was shown to be composed largely of a high molecular weight hyaluronic acid. Both the high-density and low-density capsule variants were shown to be mouse virulent with lethal dose 50 (LD50) values of 3.7×104 colony-forming units (CFU) and 3.3×105 CFU, respectively. Opsonophagocytic assays with human peripheral polymorphonuclear leukocytes demonstrated that only the LDC organism could be phagocytized and killed in the presence of white blood cells, specific antibody, and complement.