Biomedical subjects

D C Straus

Publications and source records attributed to D C Straus.

At least 19 recordsLinked to original sources

PubMed1999

Continually measured fungal profiles in sick building syndrome.

Buildings with indoor air quality (IAQ) complaints frequently have high airborne concentrations of Penicillium species, while buildings with few IAQ complaints have an indoor air (IDA) fungal ecology similar to outdoor air (ODA), where Cladosporium species is usually the dominant microorganism. These studies compared fungal air profiles, measured continually over 6 h in a documented sick building, in IDA in a room experiencing IAQ problems with fungal profiles measured concurrently in ODA. The dominant species collected at both sites were Penicillium species, Cladosporium species, and Alternaria species. In the IDA, Penicillium species were always the dominant organisms, ranging from 150 to 567 cfu/m3 (89.8-100% of the total fungi). In the ODA, Cladosporium species were dominant in four samples (40.0-70.6%), while Penicillium species were dominant (52.7-79.6%) in two. These data demonstrate that, even though ODA fungal profiles are changing continuously, IDA fungal profiles in "sick" buildings tend to remain unchanged.

Air Microbiology↗

PubMed1998

Cross-protection studies with three serotypes of Pasteurella haemolytica in the goat model.

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.

Animals↗

PubMed1998

Pasteurella haemolytica ultraviolet-irradiated vaccine by parenteral and aerosol routes compared in the goat model.

Positive control 1 (PC1) (n = 9) goats were injected transthoracically into the left lung with live Pasteurella haemolytica biovar A, serovar 1 (PhA1) in polyacrylate (PA) beads on days 0 and 21. Positive control 2 (PC2) (n = 6) goats were nebulized with live PhA1 and PA beads on days 0 and 21. Negative control (NC) goats (n = 6) were each injected transthoracically into the left lung with PA beads alone on days 0 and 21. Four groups (n = 6) were administered PA beads mixed with ultraviolet (UV) killed PhA1 on days 0 and 21. The treatment doses of bacteria for these groups were principal group 1 (PR1) injected into the left lung (7.7 x 10(10) cfu); PR2, 7.7 x 10(10) UV-killed PhA1 injected subcutaneously (SC); PR3, 7.7 x 10(10) UV-killed PhA1 injected SC only on day 21; PR4, nebulized with PA beads mixed with 5.6 x 10(10) cfu of UV-killed PhA1; and PR5, nebulized with PA beads mixed with 5 x 10(8) cfu of UV-killed PhA1. All goats were challenged transthoracically in the right lung with 1 x 10(8) cfu of live PhA1 on day 42 and necropsied on day 46. The sizes of consolidated lung lesions at the challenge site were used as a measure of immunity. The data show that the introduction of live PhA1 into the lungs of goats, either by injection or aerosolization, offers excellent protection against a subsequent homologous challenge. The data also demonstrate that two transthoracic injections (21 days apart) of UV-killed PhA1 (PR1), and subcutaneous injection of UV-killed PhA1(PR2) also offer excellent protection against a subsequent homologous live PhA1 challenge. One SC injection of UV-killed PhA1 (PR3) appears to offer only partial protection against a subsequent homologous live PhA1 challenge. Inhalation of UV-killed PhA1 mixed with PA beads (PR4 and PR5) induced no protection in goats against a subsequent live PhA1 transthoracic challenge.

Aerosols↗

PubMed1998

In vivo production of neuraminidase by Pasteurella haemolytica in market stressed cattle after natural infection.

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.

Animals↗

PubMed1998

Correlation between the prevalence of certain fungi and sick building syndrome.

OBJECTIVE: To examine the role of fungi in the production of sick building syndrome. METHODS: A 22 month study in the United States of 48 schools (in which there had been concerns about health and indoor air quality (IAQ). Building indoor air and surface samples, as well as outdoor air samples were taken at all sites to look for the presence of fungi or their viable propagules. RESULTS: Five fungal genera were consistently found in the outdoor air and comprised over 95% of the outdoor fungi. These genera were Cladosporium (81.5%), Penicillium (5.2%), Chrysosporium (4.9%), Alternaria (2.8%), and Aspergillus (1.1%). At 20 schools, there were significantly more colony forming units per cubic metre (CFU/m3) (p < 0.0001) of propagules of Penicillium species in the air samples from complaint areas when compared with the outdoor air samples and the indoor air samples from noncomplaint areas. At five schools, there were more, although not significant (p = 0.10), Penicillium propagules in the air samples from complaint areas when compared with the outdoor air samples and the indoor air samples from noncomplaint areas. In 11 schools, the indoor air (complaint areas) fungal ratios were similar to that in the outdoor air. In these 11 schools Stachybotrys atra was isolated from swab samples of visible growth under wetted carpets, on wetted walls, or behind vinyl wall coverings. In the remaining 11 schools, the fungal ratios and CFU/m3 of air were not significantly different in different areas. Many of the schools took remedial action that resulted in an indoor air fungal profile that was similar to that outdoors. CONCLUSIONS: Propagules of Penicillium and Stachybotrys species may be associated with sick building syndrome.

Air Microbiology↗

PubMed1997

Serotyping and enzyme characterization of Pasteurella haemolytica and Pasteurella multocida isolates recovered from pneumonic lungs of stressed feeder calves.

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.

Animals↗

PubMed1997

Efficacy of a subcutaneously administered, ultraviolet light-killed Pasteurella multocida A:3-containing bacterin against transthoracic challenge exposure in goats.

OBJECTIVE: To determine the effectiveness of Pasteurella multocida biovar A, serovar 3 (Pm A:3) killed by exposure to UV light and incorporated with a polyacrylate bead carrier as a vaccine. ANIMALS: 18 weanling male Spanish goats. PROCEDURE: Prospective, randomized controlled study with 3 treatment groups: positive-control (PC), negative-control (NC), and principal Pm A:3 bacterin (PA) groups. Six PC goats each received live Pm A:3 and polyacrylate beads twice, 22 days apart, by transthoracic injection into the left lung. Six NC goats each received only PA beads twice, 22 days apart, by transthoracic injection. Six principal goats each received Pm A:3 vaccine SC twice, 22 days apart. Fourteen days after the second vaccination, all goats were challenge exposed with live Pm A:3 by transthoracic injection into the right lung, and 4 days later they were euthanatized and necropsied. RESULTS: Mean volume of consolidated lung tissue at the challenge site was 1.75 cm3 for the PC group, 15.18 cm3 for the NC group, and 3.9 cm3 for the PA vaccine group. The NC group had a significantly (P < or = 0.002) larger mean volume of consolidated lung tissue than did the PC and PA groups after challenge exposure. CONCLUSIONS: The PA bacterin and the PC groups developed protective immunity against live Pm A:3 challenge exposure. An SC administered, UV light-killed, Pm A:3 bacterin induced protective immunity similar to that induced by virulent live Pm A:3 injected into the target organ, the lung.

Animals↗

PubMed1996

In vivo production of neuraminidase by Pasteurella multocida A:3 in goats after transthoracic challenge.

Six goats were injected transthoracically with live Pasteurella multocida A:3 to examine if an extracellular enzyme, neuraminidase, was produced in vivo during infection with this organism. The principal group of goats (n = 6) each received 1 ml of live 7.5 x 10(4) cfu of P. multocida mixed with polyacrylate beads transthoracically in the left lung on day 0 and 1 ml of live P. multocida (2.2 x 10(8) cfu) mixed with polyacrylate beads transthoracically in the left lung on day 22. Six goats were used as negative controls and received 0.3 g of polyacrylate beads subcutaneously in the right flank on days 0 and 22. Serum was obtained from all animals on days 0, 7, 14, 22, 29, and 36. Preimmune sera from all animals showed no detectable antibody to P. multocida A:3 neuraminidase in an enzyme neutralization assay. None of the sera from the negative control animals demonstrated a significant antibody titer against the P. multocida A:3 neuraminidase. On day 36, serum samples from the six infected animals possessed complete enzyme-neutralizing activity. Anti-neuraminidase antibody could be detected as early as day 14 in the infected animals. These data show that neuraminidase is produced in vivo during an active P. multocida A:3 lobar infection.

Animals↗

PubMed1996

Characterization of neuraminidases produced by various serotypes of Pasteurella multocida.

Neuraminidases produced by 16 strains of Pasteurella multocida (serotypes 1 to 16) were characterized by molecular weight, substrate specificity, and antigenic identity. After growth in a chemically defined medium, stage I (lyophilized) culture supernatants were assayed for activity with N-acetylneuramin lactose, human alpha-1-acid glycoprotein, fetuin, colominic acid, and bovine submaxillary mucin. Neuraminidase produced by P. multocida A:3 was purified by a combination of salt fractionation, ion-exchange chromatography on DEAE-Sephacel, and gel filtration on Sephadex G-200. Purified P. multocida A:3 neuraminidase was employed to immunize rabbits, and the resulting antiserum reduced the activity of the P. multocida A:3 enzyme by 40.3%. This antiserum also reduced the activities of the neuraminidases produced by other serotypes by between 30.8 and 59.6%. Molecular weight estimates of the neuraminidases produced by the various serotypes were obtained by gel filtration chromatography on Sephadex G-200. Each of the 16 serotypes examined produced a neuraminidase with a molecular weight of approximately 500,000. In addition, all 16 high-molecular-weight neuraminidases showed similar substrate specificities. On the basis of these data, it appears that the high-molecular-weight neuraminidases produced by different P. multocida serotypes are quite similar.

Animals↗

PubMed1996

Efficacy of a subcutaneously administered, ultraviolet light-killed Pasteurella haemolytica A1-containing vaccine against transthoracic challenge exposure in goats.

OBJECTIVE: To determine the effectiveness of Pasteurella haemolytica biovar A, serovar 1 (Ph A1) killed by UV light and incorporated with an oil adjuvant or carriers. ANIMALS: 40 weaning male Spanish goats. PROCEDURE: Goats were randomly allotted to 1 of 6 treatment groups: 4 Ph A1 bacterins (agar beads, polyacrylate beads [PA], phosphate-buffered saline solution, Freund's incomplete adjuvant), live Ph A1 with polyacrylate beads (LiPhPA), and polyacrylate beads (UnVac). Each of 4 Ph A1 vaccines was administered SC twice, 21 days apart, to 1 of 4 groups; another group received only PA beads SC, and the last group received live Ph A1 with PA beads by transthoracic injection into the left lung. 14 days after the second vaccination, all goats were challenge exposed with live Ph A1 by transthoracic injection into the right lung, and 4 days later, all goats were euthanatized and necropsied. RESULTS: Mean volume of consolidated right lung tissue was 1.02 cm3 for the LiPhPA group, 168.1 cm3 for the UnVac group, 2.3 cm3 for the Freund's incomplete adjuvant bacterin group, 5.53 cm3 for the PA bacterin group, 9.01 cm3 for the agar beads bacterin group, and 7.51 cm3 for the phosphate-buffered saline solution bacterin group. Mean volume of consolidated lung tissue was significantly different between the UnVac group and the other 5 groups. CONCLUSION: The LiPhPA group and 4 bacterin groups developed protective immunity against live Ph A1 challenge exposure. CLINICAL RELEVANCE: An s.c. administered, UV light-killed Ph A1 bacterin induced protective immunity equal to that induced by virulent live Ph A1 injected into the target organ, the lung.

Animals↗

PubMed1995

Extracellular neuraminidase production by Pasteurella species isolated from infected animals.

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.

Animals↗

PubMed1995

Complex interaction between different proteinaceous components within the cell-wall structure of Candida albicans.

We have previously described a monoclonal antibody, MAb DC3:H10, which recognized an epitope preferentially expressed on the surface of Candida albicans germ tubes. In the present study we examined the MAb-reactive material further. Immunoblot analysis of the material purified partially by Sephadex G-200 and DEAE-Sephacel chromatography reacted with antibodies to the C. albicans C3d receptor (CR2). In an ELISA, MAb DC3:H10 captured antigen that was recognized by both anti-CR2 and anti-mp58 fibrinogen binding mannoprotein polyclonal antibodies. The MAb DC3:H10 failed to compete with either of these antisera in an ELISA. Indirect immunofluorescence (IIF) analysis showed differences in surface distribution for the MAb DC3:H10, the CR2, and the mp 58 epitopes. Dual labeling IIF experiments showed MAb DC3:H10 binding to be unaffected by binding of fibrinogen or anti-mp58 antibody. However, the binding patterns of MAb DC3:H10 were modified in the presence of anti-CR2 antibody, suggesting a complex interaction between these cell wall components.

Antibodies, Fungal↗

PubMed1995

Extracellular neuraminidase production by a Pasteurella multocida A:3 strain associated with bovine pneumonia.

The properties of an extracellular neuraminidase produced by a Pasteurella multocida A:3 strain that was isolated in a case of bovine pneumonia were examined during growth in a defined medium. This enzyme (isolated from concentrated culture supernatants of P. multocida A:3) was active against N-acetylneuramin lactose, human alpha-1-acid glycoprotein, fetuin, colominic acid, and bovine submaxillary mucin. Enzyme elaboration was correlated with the growth of the organism in a defined medium, with maximum quantities produced in the stationary phase. The enzyme was purified by a combination of ammonium sulfate fractionation, ion exchange on DEAE-Sephacel, and gel filtration on Sephadex G-200. The purified neuraminidase possessed a specific activity of 9.36 mumol of sialic acid released per min per mg of protein against fetuin. The enzyme possessed a pH optimum of 6.0 and a Km of 0.03 mg/ml. The P. multocida A:3 neuraminidase had a molecular weight of approximately 500,000 as estimated by gel filtration. The enzyme was stable at 4 and 37 degrees C for 3 h. Approximately 75% of the neuraminidase activity was lost within 30 min at 50 degrees C. Greater than 90% of the enzyme activity was destroyed within 10 min at temperatures of > or = 65 degrees C. The P. multocida neuraminidase does not appear to be serologically related to the Pasteurella haemolytica A1 neuraminidase since antiserum prepared against the purified P. haemolytica enzyme did not neutralize the P. multocida enzyme.

Animals↗

PubMed1994

In vivo production of neuraminidase by Pasteurella haemolytica A1 in goats after transthoracic challenge.

Nine goats were injected transthoracically with Pasteurella haemolytica A1 to determine if an extracellular bacterial enzyme, neuraminidase, was produced in vivo during infection with this organism. The principal group of goats (n = 9) each received 1 ml of 7.25 x 10(5) live P. haemolytica A1 cells in polyacrylate beads transthoracically in the left lung on days 0 and 21. Six goats were used as negative controls and received 0.3 g of polyacrylate beads subcutaneously in the right flank on days 0 and 21. Serum was obtained from all animals on days -4, 3, 7, 14, 21, 24, and 32. Preimmune serum from all animals showed no detectable antibody to P. haemolytica A1 neuraminidase in an enzyme neutralization assay. None of the sera from the negative control animals possessed a significant antibody concentration in response to the P. haemolytica A1 neuraminidase. On day 32, serum samples from the nine infected animals possessed enzyme neutralizing activity that ranged from 62% to 100%. Anti-neuraminidase antibody could be detected as early as day 14 by the enzyme neutralization assay. These data demonstrate that the enzyme neuraminidase is produced in vivo during an active P. haemolytica A1 lobar infection.

Animals↗

PubMed1993

Salicylate potentiates amikacin therapy in rodent models of Klebsiella pneumoniae infection.

In vitro effects of salicylate on Klebsiella pneumoniae include capsule repression and enhanced aminoglycoside activity. The effects of high-dose salicylate on amikacin therapy were assessed in animal models. In a mouse lethality model, amikacin protective doses were reduced up to 12-fold by salicylate doses of 277 mg/kg. Salicylate alone increased the LD50 for K. pneumoniae in mice by nearly 1 log unit. In a lobar pneumonia model, rats received salicylate-amikacin intravenously 3 days after challenge, and bacteria were quantified from lung tissue on day 7. Rats receiving one-fourth the minimum effective amikacin dose had 1 x 10(6) cfu/g of lung, while no bacteria were detected in those also receiving salicylate (173 mg/kg). At one-eighth the minimum effective dose of amikacin, salicylate prevented the development of pneumonia. Salicylate potentiation of antimicrobial therapy far surpassed that observed in vitro, yet the potentiation was abolished in neutropenic animals. Thus, salicylate may enhance phagocytosis rather than antibiotic action in therapy.

Amikacin↗

PubMed1993

Neuraminidase production by a Pasteurella haemolytica A1 strain associated with bovine pneumonia.

The properties of an extracellular neuroaminidase produced by a Pasteurella haemolytica A1 strain (isolated from a case of bovine pneumonia) during growth in a defined medium were examined in this investigation. This enzyme, isolated from concentrated culture supernatants of P. haemolytica A1, was active against N-acetylneuramin lactose, human alpha 1-acid glycoprotein, fetuin, and bovine submaxillary mucin. Neuraminidase production paralleled bacterial growth in a defined medium and was maximal in the stationary phase of growth. The enzyme was purified to homogeneity by a combination of salt fractionation, ion-exchange chromatography on DEAE-Sephacel, and gel filtration on Sephadex G-200. These procedures yielded an enzyme preparation that possessed a specific activity of 100.62 mumol of sialic acid released per min per mg of protein against human alpha 1-acid glycoprotein. The Km value for this enzyme with human alpha 1-acid glycoprotein as the substrate was 1.1 mg/ml, and the enzyme possessed a pH optimum of 6.5. The P. haemolytica A1 neuraminidase had a molecular weight of approximately 150,000 as estimated by gel filtration and approximately 170,000 when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme was stable at 4 degrees C for 3 h. At 37 degrees C for 3 h, 25% of enzymatic activity was lost. Approximately 55% of the enzyme activity was lost within 30 min at 50 degrees C, with greater than 70% of the enzyme activity being destroyed within 10 min at temperatures of > or = 65 degrees C.

Animals↗

PubMed1993

Characterization of neuraminidases produced by various serotypes of Pasteurella haemolytica.

Neuraminidases produced by 16 strains of Pasteurella haemolytica (serotypes 1 to 16) were characterized by molecular weight, antigenic identity, and substrate specificity. After growth in a chemically defined medium, stage I (lyophilized) culture supernatants were assayed for activity with N-acetylneuramin lactose, human alpha-1-acid glycoprotein, fetuin, colominic acid, and bovine submaxillary mucin. Neuraminidase produced by P. haemolytica serotype A1 (Ph A1) was purified by a combination of salt fractionation, ion-exchange chromatography on DEAE-Sephacel, and gel filtration on Sephadex G-200. Purified Ph A1 neuraminidase was used to immunize rabbits, and the resultant antiserum reduced the activity of Ph A1 neuraminidase by 46%. This antiserum also reduced the activity of neuraminidase produced by the other serotypes by between 15 and 66%. Molecular weight estimates of the neuraminidases produced by the various serotypes were obtained by gel filtration chromatography on Sephadex G-200. Fifteen of the 16 serotypes examined produced a neuraminidase with a molecular weight of approximately 150,000 to 200,000. One serotype (serotype 11) produced no material with neuraminidase activity. In addition, all 15 high-molecular-weight neuraminidases showed similar substrate specificities. That is, they were all most active against N-acetylneuramin lactose and least active against bovine submaxillary mucin. On the basis of these results, it appears that the high-molecular-weight neuraminidases produced by the different P. haemolytica serotypes are quite similar.

Mannheimia haemolytica↗

PubMed1993

Efficacy of Pasteurella haemolytica subunit antigens in a goat model of pasteurellosis.

The effectiveness of Pasteurella haemolytica biovar A, serovar 1 (Ph1) subunit vaccines was tested in goats, using challenge exposure by transthoracic injection. Twenty-two weanling male Spanish goats were randomly allotted to 4 groups. Six goats were given 2 transthoracic injections into the lung 18 days apart with live Ph1 impregnated in agar beads (positive controls). Six goats were not given injections (negative controls). Five goats were given 2 transthoracic injections into the lung 18 days apart with 4.6 mg of cytotoxin in agar beads. The remaining 5 goats were given 2 IM injections, 18 days apart, into the thigh with 4.6 mg of cytotoxin emulsified in incomplete Freund's adjuvant. Twenty-four days after the second injection, all goats were challenge-exposed to live Ph1 by transthoracic injection into the lung, and 4 days later, all goats were euthanatized and necropsied. Serum neutralizing anticytotoxin titer was measured throughout the experiment. Mean volume of consolidated lung tissue was 0.38 cm3 for the positive control group, 32 cm3 for the negative control group; 19 cm3 for the cytotoxin-lung group; and 88 cm3 for the cytotoxin-adjuvant-IM group. Only the positive control group was protected from Ph1 challenge exposure. The Ph1 cytotoxin subunit vaccine alone appeared to be ineffective, and the anticytotoxin titer was not correlated with protection. In a separate trial, 32 weanling male Spanish goats were randomly allotted to 5 groups. Each was given 2 transthoracic injections into the lung 22 days apart. Six goats were given Ph1 cytotoxin impregnated into agar beads; 6 were given Ph1 lipopolysaccharide impregnated in agar beads; 6 were given Ph1 capsule impregnated in agar beads. Six goats were given agar beads only (negative controls), and 6 were given live Ph1 impregnated into agar beads (positive controls). Twenty days after the second injection, all goats were challenge-exposed to live Ph1 by transthoracic injection into the lung, and 4 days later, all goats were euthanatized and necropsied. Mean volume of consolidated lung tissue was 0.14 cm3 for the positive control group, 7.59 cm3 for the negative control group, 11.21 cm3 for the cytotoxin group, 10.19 cm3 for the lipopolysaccharide group, and 1.6 cm3 for the capsule group. Again, only injection of live Ph1 (positive controls) induced solid protection; however, the capsule subunit vaccine induced partial protection against challenge exposure in this trial. Lipopolysaccharide and cytotoxin subunit vaccines were ineffective in protecting goats against challenge exposure with live Ph1.

Animals↗