title: Molecular typing and differences in biofilm formation and antibiotic susceptibilities among Prototheca strains isolated in Italy and Brazil.
abstract: Bovine mastitis caused by Prototheca is a serious and complex problem that accounts for high economic losses in the dairy industry. The main objective of this study was to identify and characterize at genetic level different Prototheca strains and provide the most complete data about protothecal antibiotic resistance. The study involves 46 isolates from Italian (13 strains) and Brazilian (33 strains) mastitic milk. These strains were identified by multiplex PCR and single strand conformation polymorphism analysis and characterized by randomly amplified polymorphic DNA (RAPD)-PCR. Moreover, biofilm production and antibiotic susceptibility were evaluated. Forty-two strains resulted as Prototheca zopfii genotype 2, whereas 4 isolates could belong to a potential new Prototheca species. The RAPD-PCR, performed with 3 primers (M13, OPA-4, and OPA-18), showed a notable heterogeneity among isolates and grouped the strains according to the species and geographical origin. Biofilm production was species-dependent and P. zopfii genotype 2 strains were classified as strong biofilm producers. In vitro antibiotic susceptibility tests indicated that Prototheca strains were susceptible to antibacterial drugs belonging to aminoglycosides group; the highest activity against Prototheca strains was observed in the case of colistin sulfate, gentamicin, and netilmicin (100% of susceptible strains). It is interesting to note that all the Italian P. zopfii genotype 2 strains showed lower minimum inhibitory concentration values than the Brazilian ones. Nisin showed more efficacy than lysozyme and potassium sorbate, inhibiting 31% of the strains. Results obtained in this study confirmed that RAPD-PCR is a rapid, inexpensive, and highly discriminating tool for Prototheca strains characterization and could give a good scientific contribution for better understanding the protothecal mastitis in dairy herd.
authors.affiliation: Institute of Sciences of Food Production, Italian National Research Council, 20133 Milan, Italy. Electronic address: stefano.morandi@ispa.cnr.it.
authors.forename: S
authors.initials: S
authors.lastname: Morandi
authors.affiliation: Institute of Agricultural Biology and Biotechnology, National Research Council, 26900 Lodi, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Cremonesi
authors.affiliation: Institute of Agricultural Biology and Biotechnology, National Research Council, 26900 Lodi, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Capra
authors.affiliation: Institute of Sciences of Food Production, Italian National Research Council, 20133 Milan, Italy.
authors.forename: T
authors.initials: T
authors.lastname: Silvetti
authors.affiliation: Institute of Sciences of Food Production, Italian National Research Council, 20133 Milan, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Decimo
authors.affiliation: Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna (IZSLER), 26900 Lodi, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Bianchini
authors.affiliation: Department of Veterinary Hygiene and Public Health, Universidade Estadual Paulista (UNESP), 18618-970 Botucatu, SP, Brazil.
authors.forename: A C
authors.initials: AC
authors.lastname: Alves
authors.affiliation: Department of Preventive Veterinary Medicine, Universidade Federal de Santa Maria (UFSM), 97105-900, Santa Maria, RS, Brazil.
authors.forename: A C
authors.initials: AC
authors.lastname: Vargas
authors.affiliation: Department of Veterinary Medicine, Universidade Federal de Lavras, 37200000, Larvas, MG, Brazil.
authors.forename: G M
authors.initials: GM
authors.lastname: Costa
authors.affiliation: Department of Veterinary Hygiene and Public Health, Universidade Estadual Paulista (UNESP), 18618-970 Botucatu, SP, Brazil.
authors.forename: M G
authors.initials: MG
authors.lastname: Ribeiro
authors.affiliation: Institute of Sciences of Food Production, Italian National Research Council, 20133 Milan, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Brasca
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents; D018441:Biofilms; D001938:Brazil; D002417:Cattle; D007558:Italy; D008414:Mastitis, Bovine / Q000382:microbiology; D058889:Molecular Typing; D011525:Prototheca / Q000235:genetics*; D019105:Random Amplified Polymorphic DNA Technique
chemical_list: D000900:Anti-Bacterial Agents
keywords: Prototheca; antibiotic susceptibility; biofilm production; netilmicin; randomly amplified polymorphic DNA (RAPD)-PCR