Evaluation of Chromogenic Culture Media for Rapid Identification of Gram-Positive Bacteria Causing Mastitis
The present study aimed to evaluate the diagnostic performance specificity (Sp), sensitivity (Se), positive predictive value (PPV), negative predictive value (NPV), and accuracy (Acc) of two chromogenic culture media for rapid identification of Gram-positive bacteria causing subclinical mastitis (SC...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2021-04-01
|
| Series: | Frontiers in Veterinary Science |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fvets.2021.662201/full |
| _version_ | 1819320474304249856 |
|---|---|
| author | Breno Luis Nery Garcia Carlos Eduardo Fidelis Gustavo Freu Brunna de Mattos Granja Marcos Veiga dos Santos |
| author_facet | Breno Luis Nery Garcia Carlos Eduardo Fidelis Gustavo Freu Brunna de Mattos Granja Marcos Veiga dos Santos |
| author_sort | Breno Luis Nery Garcia |
| collection | DOAJ |
| description | The present study aimed to evaluate the diagnostic performance specificity (Sp), sensitivity (Se), positive predictive value (PPV), negative predictive value (NPV), and accuracy (Acc) of two chromogenic culture media for rapid identification of Gram-positive bacteria causing subclinical mastitis (SCM) in dairy cows. For this, the performance of chromogenic culture media Gram-positive (GP) and Staphylococcus (Staph) (CHROMagar ™, Paris—France) was evaluated in milk samples collected from: (1) lactating cows with SCM (n = 504), and (2) cows in the post-partum period (PP) (7 ± 3 days post-partum; n = 536). Rapid identification of Gram-positive bacteria in chromogenic media was performed by visual inspection of colony colors after 24 h of incubation at 37°C. Bacterial identification by MALDI-TOF mass spectrometry was considered the reference methodology for calculating: Acc, Se, Sp, PPV, NPV, and Cohen's Kappa coefficient of agreement (k). The chromogenic media GP showed high Acc for Strep. agalactiae/dysgalactiae identification in both samples of SCM (Se: 89.1%; Sp: 96.3% and Acc: 95.6%) and of cows in PP (Se: 100%; Sp: 99.0% and Acc: 99.1%). Similar results were observed for Strep. uberis/Enterococcus spp. identification (Se: 90.5%; Sp: 92.5% and Acc: 92.3%) in SCM samples and Se: 100%; Sp: 99.6% and Acc: 99.6% in samples of PP cows using the GP media. However, the GP chromogenic media showed low Se (25.0% in SCM samples and 50.0% in samples of cows in PP) for Staph. aureus identification, despite Sp and Acc were high (Sp: 98.3% and Acc: 95.4% in SCM and Sp samples: 99.4% and Acc: 98.9% in PP cow samples). Staph culture media showed high Acc for Staph. aureus identification (Se: 80.0%; Sp: 98.8% and Acc: 98.0% in SCM samples and Se: 66.7%; Sp: 100% and Acc: 99.6% in PP cow samples), although the low prevalence of Staph. epidermidis and Staph. saprophyticus limit inferences about the performance of identifying these pathogens in Staph media. In conclusion, despite the limitation of the GP media for identification of Staph. aureus, GP, and Staph chromogenic media obtained satisfactory diagnostic performance results for the rapid identification of the main Gram-positive pathogens associated with SCM. |
| first_indexed | 2024-12-24T11:20:09Z |
| format | Article |
| id | doaj.art-9c191db404734dfb8bb85d94353061c6 |
| institution | Directory Open Access Journal |
| issn | 2297-1769 |
| language | English |
| last_indexed | 2024-12-24T11:20:09Z |
| publishDate | 2021-04-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Veterinary Science |
| spelling | doaj.art-9c191db404734dfb8bb85d94353061c62022-12-21T16:58:16ZengFrontiers Media S.A.Frontiers in Veterinary Science2297-17692021-04-01810.3389/fvets.2021.662201662201Evaluation of Chromogenic Culture Media for Rapid Identification of Gram-Positive Bacteria Causing MastitisBreno Luis Nery GarciaCarlos Eduardo FidelisGustavo FreuBrunna de Mattos GranjaMarcos Veiga dos SantosThe present study aimed to evaluate the diagnostic performance specificity (Sp), sensitivity (Se), positive predictive value (PPV), negative predictive value (NPV), and accuracy (Acc) of two chromogenic culture media for rapid identification of Gram-positive bacteria causing subclinical mastitis (SCM) in dairy cows. For this, the performance of chromogenic culture media Gram-positive (GP) and Staphylococcus (Staph) (CHROMagar ™, Paris—France) was evaluated in milk samples collected from: (1) lactating cows with SCM (n = 504), and (2) cows in the post-partum period (PP) (7 ± 3 days post-partum; n = 536). Rapid identification of Gram-positive bacteria in chromogenic media was performed by visual inspection of colony colors after 24 h of incubation at 37°C. Bacterial identification by MALDI-TOF mass spectrometry was considered the reference methodology for calculating: Acc, Se, Sp, PPV, NPV, and Cohen's Kappa coefficient of agreement (k). The chromogenic media GP showed high Acc for Strep. agalactiae/dysgalactiae identification in both samples of SCM (Se: 89.1%; Sp: 96.3% and Acc: 95.6%) and of cows in PP (Se: 100%; Sp: 99.0% and Acc: 99.1%). Similar results were observed for Strep. uberis/Enterococcus spp. identification (Se: 90.5%; Sp: 92.5% and Acc: 92.3%) in SCM samples and Se: 100%; Sp: 99.6% and Acc: 99.6% in samples of PP cows using the GP media. However, the GP chromogenic media showed low Se (25.0% in SCM samples and 50.0% in samples of cows in PP) for Staph. aureus identification, despite Sp and Acc were high (Sp: 98.3% and Acc: 95.4% in SCM and Sp samples: 99.4% and Acc: 98.9% in PP cow samples). Staph culture media showed high Acc for Staph. aureus identification (Se: 80.0%; Sp: 98.8% and Acc: 98.0% in SCM samples and Se: 66.7%; Sp: 100% and Acc: 99.6% in PP cow samples), although the low prevalence of Staph. epidermidis and Staph. saprophyticus limit inferences about the performance of identifying these pathogens in Staph media. In conclusion, despite the limitation of the GP media for identification of Staph. aureus, GP, and Staph chromogenic media obtained satisfactory diagnostic performance results for the rapid identification of the main Gram-positive pathogens associated with SCM.https://www.frontiersin.org/articles/10.3389/fvets.2021.662201/fullchromogenic mediamicroorganism identificationmastitismilk qualityon-farm culture |
| spellingShingle | Breno Luis Nery Garcia Carlos Eduardo Fidelis Gustavo Freu Brunna de Mattos Granja Marcos Veiga dos Santos Evaluation of Chromogenic Culture Media for Rapid Identification of Gram-Positive Bacteria Causing Mastitis Frontiers in Veterinary Science chromogenic media microorganism identification mastitis milk quality on-farm culture |
| title | Evaluation of Chromogenic Culture Media for Rapid Identification of Gram-Positive Bacteria Causing Mastitis |
| title_full | Evaluation of Chromogenic Culture Media for Rapid Identification of Gram-Positive Bacteria Causing Mastitis |
| title_fullStr | Evaluation of Chromogenic Culture Media for Rapid Identification of Gram-Positive Bacteria Causing Mastitis |
| title_full_unstemmed | Evaluation of Chromogenic Culture Media for Rapid Identification of Gram-Positive Bacteria Causing Mastitis |
| title_short | Evaluation of Chromogenic Culture Media for Rapid Identification of Gram-Positive Bacteria Causing Mastitis |
| title_sort | evaluation of chromogenic culture media for rapid identification of gram positive bacteria causing mastitis |
| topic | chromogenic media microorganism identification mastitis milk quality on-farm culture |
| url | https://www.frontiersin.org/articles/10.3389/fvets.2021.662201/full |
| work_keys_str_mv | AT brenoluisnerygarcia evaluationofchromogenicculturemediaforrapididentificationofgrampositivebacteriacausingmastitis AT carloseduardofidelis evaluationofchromogenicculturemediaforrapididentificationofgrampositivebacteriacausingmastitis AT gustavofreu evaluationofchromogenicculturemediaforrapididentificationofgrampositivebacteriacausingmastitis AT brunnademattosgranja evaluationofchromogenicculturemediaforrapididentificationofgrampositivebacteriacausingmastitis AT marcosveigadossantos evaluationofchromogenicculturemediaforrapididentificationofgrampositivebacteriacausingmastitis |