Minimum inhibitory concentrations of chlorhexidine- and lactic acid-based teat disinfectants: An intervention trial assessing bacterial selection and susceptibility
ABSTRACT: Teat disinfection is a recommended preventive tool to improve udder health and to prevent new intramammary infections. However, side effects are discussed, such as bacterial selection of less-susceptible bacteria with the application of certain teat disinfectants. The objective of this stu...
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| Format: | Article |
| Language: | English |
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Elsevier
2022-01-01
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| Series: | Journal of Dairy Science |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022030221009802 |
| _version_ | 1811250821238620160 |
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| author | J.A. Schwenker U. Schotte C.S. Hölzel |
| author_facet | J.A. Schwenker U. Schotte C.S. Hölzel |
| author_sort | J.A. Schwenker |
| collection | DOAJ |
| description | ABSTRACT: Teat disinfection is a recommended preventive tool to improve udder health and to prevent new intramammary infections. However, side effects are discussed, such as bacterial selection of less-susceptible bacteria with the application of certain teat disinfectants. The objective of this study was to assess the species composition and bacterial in vitro susceptibility by means of an interventive trial. For this purpose, 3 different postmilking teat treatments (disinfection with 0.215% chlorhexidine or 3.5% lactic acid, or control group with no dipping) were applied to 28 cows in a 6-d intervention approach using a split-udder design. Milk samples were taken before and after intervention. Bacteria were cultured and differentiated to species or genus level by MALDI-TOF mass spectrometry. Minimum inhibitory concentrations (MIC) were determined, and MIC changes over time were recorded. Susceptibilities to chlorhexidine and lactic acid were compared between species of the genera Staphylococcus, Streptococcus, Corynebacterium, and others. Species composition changed during the intervention. Under the treatment of chlorhexidine and lactic acid, the proportion of coagulase-negative staphylococci (CNS) decreased. An increased proportion of species belonging to the genus Corynebacterium was observed especially under the application of lactic acid. Although both teat disinfectants were basically effective, isolates differed in their susceptibility to both teat disinfectants. Populations of CNS, Staphylococcus aureus, and Corynebacterium spp. showed significantly lower absolute MIC values for chlorhexidine. Compared with other species, Corynebacterium spp. showed the lowest susceptibility for chlorhexidine as well as for lactic acid. A significant increase in MIC values after 6 d of intervention was observed with the lactic acid treatment in all isolates, as well as in CNS. This increase can be interpreted as either adaptation of isolates or displacement of more-susceptible species by less-susceptible species. Further studies using long-term intervention might reveal more pronounced effects on MIC values and species composition. |
| first_indexed | 2024-04-12T16:10:27Z |
| format | Article |
| id | doaj.art-f56b0d32d5134320a0fe8111fbdfa75b |
| institution | Directory Open Access Journal |
| issn | 0022-0302 |
| language | English |
| last_indexed | 2024-04-12T16:10:27Z |
| publishDate | 2022-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Dairy Science |
| spelling | doaj.art-f56b0d32d5134320a0fe8111fbdfa75b2022-12-22T03:25:56ZengElsevierJournal of Dairy Science0022-03022022-01-011051734747Minimum inhibitory concentrations of chlorhexidine- and lactic acid-based teat disinfectants: An intervention trial assessing bacterial selection and susceptibilityJ.A. Schwenker0U. Schotte1C.S. Hölzel2Department for Animal Hygiene and Animal Health, Institute of Animal Breeding and Husbandry, Christian-Albrechts-University Kiel, 24098 Kiel, Germany; Corresponding authorDepartment A-Veterinary Medicine, Central Institute of the Bundeswehr Medical Service Kiel, 24119 Kronshagen, GermanyDepartment for Animal Hygiene and Animal Health, Institute of Animal Breeding and Husbandry, Christian-Albrechts-University Kiel, 24098 Kiel, GermanyABSTRACT: Teat disinfection is a recommended preventive tool to improve udder health and to prevent new intramammary infections. However, side effects are discussed, such as bacterial selection of less-susceptible bacteria with the application of certain teat disinfectants. The objective of this study was to assess the species composition and bacterial in vitro susceptibility by means of an interventive trial. For this purpose, 3 different postmilking teat treatments (disinfection with 0.215% chlorhexidine or 3.5% lactic acid, or control group with no dipping) were applied to 28 cows in a 6-d intervention approach using a split-udder design. Milk samples were taken before and after intervention. Bacteria were cultured and differentiated to species or genus level by MALDI-TOF mass spectrometry. Minimum inhibitory concentrations (MIC) were determined, and MIC changes over time were recorded. Susceptibilities to chlorhexidine and lactic acid were compared between species of the genera Staphylococcus, Streptococcus, Corynebacterium, and others. Species composition changed during the intervention. Under the treatment of chlorhexidine and lactic acid, the proportion of coagulase-negative staphylococci (CNS) decreased. An increased proportion of species belonging to the genus Corynebacterium was observed especially under the application of lactic acid. Although both teat disinfectants were basically effective, isolates differed in their susceptibility to both teat disinfectants. Populations of CNS, Staphylococcus aureus, and Corynebacterium spp. showed significantly lower absolute MIC values for chlorhexidine. Compared with other species, Corynebacterium spp. showed the lowest susceptibility for chlorhexidine as well as for lactic acid. A significant increase in MIC values after 6 d of intervention was observed with the lactic acid treatment in all isolates, as well as in CNS. This increase can be interpreted as either adaptation of isolates or displacement of more-susceptible species by less-susceptible species. Further studies using long-term intervention might reveal more pronounced effects on MIC values and species composition.http://www.sciencedirect.com/science/article/pii/S0022030221009802chlorhexidinelactic acidmastitis pathogensMICteat disinfection |
| spellingShingle | J.A. Schwenker U. Schotte C.S. Hölzel Minimum inhibitory concentrations of chlorhexidine- and lactic acid-based teat disinfectants: An intervention trial assessing bacterial selection and susceptibility Journal of Dairy Science chlorhexidine lactic acid mastitis pathogens MIC teat disinfection |
| title | Minimum inhibitory concentrations of chlorhexidine- and lactic acid-based teat disinfectants: An intervention trial assessing bacterial selection and susceptibility |
| title_full | Minimum inhibitory concentrations of chlorhexidine- and lactic acid-based teat disinfectants: An intervention trial assessing bacterial selection and susceptibility |
| title_fullStr | Minimum inhibitory concentrations of chlorhexidine- and lactic acid-based teat disinfectants: An intervention trial assessing bacterial selection and susceptibility |
| title_full_unstemmed | Minimum inhibitory concentrations of chlorhexidine- and lactic acid-based teat disinfectants: An intervention trial assessing bacterial selection and susceptibility |
| title_short | Minimum inhibitory concentrations of chlorhexidine- and lactic acid-based teat disinfectants: An intervention trial assessing bacterial selection and susceptibility |
| title_sort | minimum inhibitory concentrations of chlorhexidine and lactic acid based teat disinfectants an intervention trial assessing bacterial selection and susceptibility |
| topic | chlorhexidine lactic acid mastitis pathogens MIC teat disinfection |
| url | http://www.sciencedirect.com/science/article/pii/S0022030221009802 |
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