In vitro susceptibility of bovine mastitis pathogens to a combination of penicillin and framycetin: Development of interpretive criteria for testing by broth microdilution and disk diffusion

Coagulase-negative staphylococci (CNS) have emerged as bovine mastitis pathogens in many countries. CNS mastitis is generally mild but can persist in the udder for long periods. Pathogenesis of CNS intramammary infection is not well understood. In the present study, adhesion, invasion and intracellular replication of twenty-two CNS strains isolated from bovine mastitis and the effect of bovine lactoferrin (bLf) on the internalization were studied in vitro in a bovine mammary epithelial (BME) cell model. The CNS strains were ofStaphylococcus chromogenes, Staph. simulans, Staph. epidermidis, Staph. haemolyticusandStaph. cohnii urealyticus; two strains ofStaph. aureuswere used as controls. Seven of the CNS strains originated from persistent and five from transient mastitis infections. The in-vitro susceptibility of the strains to bLf was also investigated. All CNS species examined had an adhesive ability equal to that ofStaph. aureus, but internalization varied among staphylococcal strains. The antagonistic effect of bLf on the adhesion and invasion of CNS strains was weak, but bLf significantly decreased intracellular replication and replication rates of CNS. No correlation between the in-vitro susceptibility of the strain to bLf or internalization among clinical signs of mastitis was established. No difference between the persistent and transient CNS strains in adhesion, invasion or replication rate was recorded. This in-vitro BME cell model can be used to study the virulence potential of mastitis pathogens, although the severity and persistence of eventual infections shall be further investigated in vivo. The role of bLf in intramammary infection caused by CNS may be limited.

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In vitro Susceptibility Testing of Clinical Zygomyceteous Species isolated in Cairo, Egypt against Ten Antifungal Agents by Broth Microdilution, Disk Diffusion and E-test Methods

Egyptian Journal of Botany ◽

10.21608/ejbo.2016.386 ◽

2016 ◽

Vol 56 (1) ◽

pp. 255-267

Keyword(s):

Antifungal Agents ◽

Susceptibility Testing ◽

Test Methods ◽

Disk Diffusion ◽

Broth Microdilution ◽

In Vitro Susceptibility ◽

In Vitro Susceptibility Testing

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Faculty Opinions recommendation of In vitro susceptibility testing of Geotrichum capitatum: comparison of the E-test, disk diffusion, and Sensititre colorimetric methods with the NCCLS M27-A2 broth microdilution reference method.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1017212.202399 ◽

2004 ◽

Author(s):

Ana Espinel-Ingroff

Keyword(s):

Susceptibility Testing ◽

Reference Method ◽

Disk Diffusion ◽

Broth Microdilution ◽

In Vitro Susceptibility ◽

Geotrichum Capitatum ◽

In Vitro Susceptibility Testing ◽

Test Disk ◽

Colorimetric Methods

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In vitro susceptibility of Burkholderia cepacia complex isolates: Comparison of disk diffusion, Etest®, agar dilution, and broth microdilution methods

Diagnostic Microbiology and Infectious Disease ◽

10.1016/j.diagmicrobio.2016.08.015 ◽

2016 ◽

Vol 86 (4) ◽

pp. 422-427 ◽

Cited By ~ 6

Author(s):

Lorena Cristina Corrêa Fehlberg ◽

Adriana Gianinni Nicoletti ◽

Ana Carolina Ramos ◽

Fernanda Rodrigues-Costa ◽

Adriana Pereira de Matos ◽

...

Keyword(s):

Burkholderia Cepacia ◽

Burkholderia Cepacia Complex ◽

Disk Diffusion ◽

Broth Microdilution ◽

In Vitro Susceptibility ◽

Agar Dilution

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Influence of nutrient availability on in vitro growth of major bovine mastitis pathogens

Journal of Dairy Research ◽

10.1017/s0022029921000133 ◽

2021 ◽

Vol 88 (1) ◽

pp. 80-88

Author(s):

Remo Stürmlin ◽

Josef J. Gross ◽

Olga Wellnitz ◽

Lea A. Wagner ◽

Camille Monney ◽

...

Keyword(s):

Bacterial Growth ◽

Nutrient Availability ◽

Bovine Mastitis ◽

Milk Composition ◽

B Vitamins ◽

E Coli ◽

Streptococcus Uberis ◽

Whole Milk ◽

Mastitis Pathogens

AbstractThe aim of the present study was to investigate the effects of milk composition changes on the in vitro growth of bovine mastitis pathogens. Nutritional requirements of three major bovine mastitis pathogens Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Streptococcus uberis (S. uberis) were investigated in vitro. We used ultra-high temperature (UHT) treated milk with different contents of fat, protein, and carbohydrates to test the influence of the availability of various milk constituents on pathogen growth characteristics. Additionally, the bacterial growth was investigated under experimentally modified nutrient availability by dilution and subsequent supplementation with individual nutrients (carbohydrates, different nitrogen sources, minerals, and different types of B vitamins) either to milk or to a conventional medium (thioglycolate broth, TB). Varying contents of fat, protein or lactose did not affect bacterial growth with the exception of growth of S. uberis being promoted in protein-enriched milk. The addition of nutrients to diluted whole milk and TB partly revealed different effects, indicating that there are media-specific growth limiting factors after dilution. Supplementation of minerals to diluted milk did not affect growth rates of all studied bacteria. Bacterial growth in diluted whole milk was decreased by the addition of high concentrations of amino acids in S. aureus, and by urea and additional B vitamins in E. coli and S. aureus. The growth rate of S. uberis was increased by the addition of B vitamins to diluted whole milk. The present results demonstrate that growth-limiting nutrients differ among pathogen types. Because reduced bacterial growth was only shown in diluted milk or TB, it is unlikely that alterations in nutrient availability occurring as a consequence of physiological changes of milk composition in the cow's udder would directly affect the susceptibility or course of bovine mastitis.

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In Vitro Activities of Daptomycin against 2,789 Clinical Isolates from 11 North American Medical Centers

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.45.6.1919-1922.2001 ◽

2001 ◽

Vol 45 (6) ◽

pp. 1919-1922 ◽

Cited By ~ 115

Author(s):

Arthur L. Barry ◽

Peter C. Fuchs ◽

Steven D. Brown

Keyword(s):

Clinical Isolates ◽

In Vitro Activity ◽

Broth Microdilution ◽

In Vitro Susceptibility ◽

Medical Centers ◽

Mueller Hinton ◽

Calcium Cations ◽

Important Exception ◽

Mueller Hinton Broth

ABSTRACT The in vitro activity of daptomycin is affected by the concentration of calcium cations in the test medium. Mueller-Hinton broth is currently adjusted to contain 10 to 12.5 mg of magnesium per liter and 20 to 25 mg of calcium per liter, but for testing of daptomycin, greater concentrations of calcium (50 mg/liter) are recommended to better resemble the normal concentration of ionized calcium in human serum. Two levels of calcium were used for broth microdilution tests of 2,789 recent clinical isolates of gram-positive bacterial pathogens. MICs of daptomycin were two- to fourfold lower when the broth contained additional calcium. For most species, however, the percentages of strains that were inhibited by 2.0 μg of daptomycin per ml were essentially identical with the two broth media. Enterococci were the important exception; i.e., 92% were inhibited when tested in calcium-supplemented broth but only 35% were inhibited by 2.0 μg/ml without the additional calcium. This type of information should be considered when selecting criteria for defining in vitro susceptibility to daptomycin.

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Comparison of Disk Diffusion and Broth Microdilution Methods for in Vitro Antifungal Susceptibility Testing of Dermatophytes

Indian Journal of Medical Microbiology ◽

10.1016/j.ijmmb.2021.08.339 ◽

2021 ◽

Vol 39 ◽

pp. S97-S98

Author(s):

Safiya Firoze

Keyword(s):

Susceptibility Testing ◽

Antifungal Susceptibility ◽

Antifungal Susceptibility Testing ◽

Disk Diffusion ◽

Broth Microdilution ◽

In Vitro Antifungal Susceptibility

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Advances in lactoferrin research concerning bovine mastitis

Biochemistry and Cell Biology ◽

10.1139/bcb-2016-0044 ◽

2017 ◽

Vol 95 (1) ◽

pp. 69-75 ◽

Cited By ~ 7

Author(s):

Kei-ichi Shimazaki ◽

Kazuhiro Kawai

Keyword(s):

Immune System ◽

Defense Mechanism ◽

Bovine Mastitis ◽

Healthy Development ◽

Treatment And Prevention ◽

Year 2000 ◽

Mastitis Pathogens ◽

Binding Glycoprotein

Lactoferrin is a multifunctional, iron-binding glycoprotein found in milk and other exocrine secretions. Lactoferrin in milk plays vital roles in the healthy development of newborn mammals, and is also an innate resistance factor involved in the prevention of mammary gland infection by microorganisms. Inflammation of the udder because of bacterial infection is referred to as mastitis. There have been many investigations into the relationships between lactoferrin and mastitis, which fall into several categories. The main categories are fluctuations in the lactoferrin concentration of milk, lactoferrin activity against mastitis pathogens, elucidation of the processes underlying the onset of mastitis, participation of lactoferrin in the immune system, and utilization of lactoferrin in mastitis treatment and prevention. This minireview describes lactoferrin research concerning bovine mastitis. In the 1970s, many researchers reported that the lactoferrin concentration fluctuates in milk from cows with mastitis. From the late 1980s, many studies clarified the infection-defense mechanism in the udder and the contribution of lactoferrin to the immune system. After the year 2000, the processes underlying the onset of mastitis were elucidated in vivo and in vitro, and lactoferrin was applied for the treatment and prevention of mastitis.

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