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M M Jensen

Publications and source records attributed to M M Jensen.

35 records · Page 2Linked to original sources
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Preliminary studies on bacterial interference of staphylococcosis of chickens.

Previous studies indicated that Staphylococcus epidermidis strain 115 might be an effective interfering agent in reducing the rate of staphylococcosis in turkeys. In the present study, strain 115 was avirulent when administered to 3-day-old chicks by oral, aerosol, or intravenous route. Strain 115 adhered specifically to tracheal, lung, air-sac, and liver cells in vitro and interfered with subsequent colonization by virulent Staphylococcus aureus. In vivo colonization of lungs and livers of young chicks occurred following exposure to aerosols of strain 115. Strain 115 interfered with the in vivo colonization of lungs and livers by virulent S. aureus.

Animals↗
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Staphylococcosis of turkeys. 1. Portal of entry and tissue colonization.

Staphylococcus aureus and various coagulase-negative staphylococci were isolated from turkeys with staphylococcosis. Virulent S. aureus adhered well (averaged more than 100 bacteria per tissue cell) in vitro to cells from tissues of the respiratory tract but did not adhere well (averaged fewer than 12 bacteria per tissue cell) to cells from tissues of the alimentary tract. Some avirulent coagulase-negative staphylococci also adhered well to cells from the respiratory tissues. Lungs and livers of turkeys became colonized with virulent S. aureus following experimental aerosol exposure. Tracheas, livers, and hock joints of some market-age turkeys were naturally colonized with S. aureus and various species of coagulase-negative staphylococci.

Aerosols↗
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Staphylococcosis of turkeys. 2. Assay of protein A levels of staphylococci isolated from turkeys.

Ninety-eight Staphylococcus aureus isolates and 227 coagulase-negative staphylococcal isolates from turkeys were assayed for protein A content. The amount of protein A of each isolate was quantitated using a direct enzyme-linked immunosorbent assay. Of the S. aureus isolates, 83% possessed some protein A, whereas only 13% of the coagulase-negative staphylococci contained some protein A. No correlation was seen between protein A content and ability to adhere to turkey cells. No differences in virulence were seen between isolates of S. aureus possessing high or low levels of protein A; however, an isolate with no protein A was avirulent.

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Staphylococcosis of turkeys. 3. Bacterial interference as a possible means of control.

Two Staphylococcus epidermidis isolates from turkeys were used as interfering agents to help control staphylococcosis. Both isolates adhered to tissues of the turkeys' respiratory tract, interfered with attachment of virulent S. aureus, produced bacteriocins bacteriocidal to S. aureus, and were avirulent for turkeys. About 200,000 turkeys in commercial flocks were exposed to aerosols of these interfering isolates between 1 and 6 weeks of age, and many became colonized with these bacteria. The aerosol-treated turkeys had lower levels of colonization with S. aureus and had a 3% higher gross survival rate than untreated control turkeys.

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Staphylococcosis of turkeys. 4. Characterization of a bacteriocin produced by an interfering Staphylococcus.

A Staphylococcus epidermidis isolate designated strain 115, which is used as an interfering agent against staphylococcosis of turkeys, produces a bacteriocin that was partially purified and characterized in this study. This bacteriocin diffused through agar media, but it was not found in appreciable quantities in the supernatant fluid of broth cultures. Extraction of the bacterial cells with 7 M urea, 1% sodium dodecyl sulfate, or 1% Triton X-100 caused considerable amounts of the bacteriocin to go into solution. This substance was partially purified by selective chemical extraction and by gel filtration chromatography using a Sephacryl S-300 column. This bacteriocin had two active forms: an aggregate, and a small-molecular-weight form estimated by gel filtration chromatography to be less than 6500. Activity was not affected by heat, repeated freeze-thaw cycles, pH 2 and pH 10, or a variety of proteolytic enzymes, nucleases, a lipase, and lysozyme.

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Staphylococcosis of turkeys. 5. Large-scale control programs using bacterial interference.

Staphylococcus epidermidis strain 115 was used as an interfering agent to reduce the incidence of staphylococcosis in turkeys. In 1984, the entire Utah turkey population of about 3 million turkeys was exposed at 1 to 10 days and at 4 to 6 weeks of age to aerosols of strain 115. Some staphylococcosis was still observed in range turkeys but appeared to be at a lower rate than in previous years. At processing, about 30% of the turkeys were still colonized with strain 115. A control study was carried out in 1985 to quantitate the level of reduction of staphylococcosis in turkeys treated with strain 115. About 1 million turkeys were treated, and 2 million remained untreated. Flocks from both groups were examined periodically for existing cases of staphylococcosis. Of 174,250 treated turkeys examined, 90 had staphylococcosis on the days examined, whereas 255 of the 183,500 untreated turkeys that were examined had staphylococcosis. Turkeys housed in range sheds had five times the incidence of staphylococcosis that turkeys in enclosed coops had. The gross mortality rate of 200,636 treated turkeys was 2.7% lower (P less than 0.001) than that of 189,450 untreated control turkeys that were monitored.

Aerosols↗
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Use of an enzyme-linked immunosorbent assay to measure antibody responses in turkeys against Pasteurella multocida.

AN enzyme-linked immunosorbent assay (ELISA) and a microtiter agglutination (MA) test were used in a comparative study to measure the humoral antibody responses of turkeys receiving oral vaccination against fowl cholera. The ELISA was sensitive and measured antibody titers as high as 1:4,409, whereas the highest titers the MA test measured were 1:128. A close correlation was seen between ELISA antibody titers and protection against oral challenge with virulent Pasteurella multocida, whereas a poor correlation was seen between antibody titers measured by MA tests and protection. ELISA substrate reactions from a single serum dilution, measured with a spectrophotometer, could be converted directly from absorbance to antibody titers using a linear regression plot.

Agglutination Tests↗
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Field vaccination trials against turkey coryza using a temperature-sensitive mutant of Alcaligenes faecalis.

In field trials, 14 flocks of turkeys were vaccinated against coryza (rhinotracheitis) with a temperature-sensitive mutant of Alcaligenes faecalis via drinking water. Vaccine doses of 5 to 250 million bacteria per turkey were used. Turkeys ranged in age from 2.5 to 13 weeks. Doses of 5 to 7 million bacteria did not induce complete protection. Doses of 50 million bacteria or more appeared to induce substantial immunity in most flocks. Six-week-old birds receiving doses of 90 million bacteria developed a high degree of protection against challenge with virulent A. faecalis.

Administration, Oral↗
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Control of turkey Alcaligenes rhinotracheitis in Utah with a live vaccine.

During the 1980 growing season in the Sanpete Valley of Utah, about half of the 250 to 300 flocks of turkeys were vaccinated with an oral vaccine against alcaligenes rhinotracheitis (ART). The vaccine consisted of a temperature-sensitive mutant of Alcaligenes faecalis. Most vaccinated birds developed serum antibodies. No outbreaks of ART occurred in vaccinated flocks, although some outbreaks occurred in unvaccinated flocks. During 1979, when on flocks were vaccinated, over 90% of the flocks experienced outbreaks of ART during late summer.

Alcaligenes↗
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Immunization against turkey coryza by colonization with mutants of Alcaligenes faecalis.

Temperature-sensitive mutants of Alcaligenes faecalis that exhibited reduced growth at 42 C but grew well at 30 C were induced by N-methyl-N'-nitro-N-nitrosoguanidine. Four of the 5 mutants that were studied readily colonized the nasal mucosa of turkeys when given intranasally or in drinking water. Several mutants caused no signs of coryza or depression and produced minimal colonization of the trachea. Colonization of the nasal mucosa lasted 3 to 4 weeks and induced moderate levels of serum antibodies. When challenged with virulent isolates of A. faecalis 4 to 6 weeks after having been exposed to the mutants, unstressed turkeys were protected; turkeys subjected to water deprivation exhibited some colonization with the virulent strain and showed slight signs of coryza.

Alcaligenes↗
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Staphylococcosis of turkeys. 6. Development of penicillin resistance in an interfering strain of Staphylococcus epidermidis.

Staphylococcus epidermidis strain 115, used as an interfering agent to help reduce the incidence of staphylococcosis in turkeys, was converted into a penicillin- and chloramphenicol-resistant strain designated 115R. This was accomplished by introducing a plasmid carrying the beta-lactamase (penicillinase) and chloramphenicol-resistance genes into S. epidermidis 115 by electroporation. The resultant strain, 115R, was an efficient producer of beta-lactamase and had marked increased resistance to penicillin and chloramphenicol. A beta-lactamase DNA probe was used to confirm the presence of the beta-lactamase gene in strain 115R. S. epidermidis strain 115R retained the characteristics of tissue adherence, bacteriocin production, and non-virulence that were present in the original non-transformed strain 115, and in addition should theoretically remain colonized in poults following treatment with penicillin.

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Occlusive laryngotracheitis in turkeys following drinking water administration of gentian violet.

Acute respiratory signs and increased mortality due to suffocation occurred in a flock of 5-week-old male turkey poults following water administration of gentian violet. Gross lesions of laryngeal edema and occlusion of the tracheal opening with caseous plugs were present. Microscopic lesions in the tracheas consisted of vascular congestion, mucosal degeneration, and necrosis. The condition was reproduced experimentally in turkey poults by giving drinking water containing gentian violet.

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Colicin V38 and microcin C38 produced by Escherichia coli strain 38.

Escherichia coli strain 38, an isolate from turkeys, has been previously shown to produce one or more broad-spectrum bacteriocins against other related enteric bacteria. Using a collection of E. coli strains that synthesized well-characterized colicins or microcins, along with a set of colicin/microcin-insensitive mutants, we were able to classify the bacteriocins produced by strain 38. We determined that strain 38 produced a microcin (microcin C38) and a colicin (colicin V38) and that the amount of microcin C38 depended on the type of media on which it was grown. Escherichia coli strain 38 was found to have cross-immunity with the microcin C7-producing strain MC4100 and with the colicin V-producing strain 4674. OmpF mutant cells were found to be insensitive to microcin C38, whereas colicin V38 was not active on cells that had a cir mutation. Both microcin C38 and colicin V38 were inactivated by proteases. Microcin C38 was stable at extremes of pH (pH 1.5 and pH 13) and heat (10 min at 98 C) conditions, whereas colicin V38 was not. In addition, microcin C38 was found to be active against a broader spectrum of gram-negative bacteria than was colicin V38.

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