Genotypic and phenotypic diversity of Prototheca spp. recovered from bovine mastitis in terms of antimicrobial resistance and biofilm formation ability

Abstract

Background The Prototheca algae have recently emerged as an important cause of bovine mastitis globally. Isolates from bovine mastitis in several countries were nearly all identified as P. bovis, suggesting that it was the main causative agent of bovine protothecal mastitis. The aim of the present study was to evaluate the presence and isolation of Prototheca spp. in dairy farms, detect the genetic diversity among strains, determine the capacity of producing biofilm and their resistance to antifungal and antimicrobial drugs. Results A total of 48 Prototheca isolates from four different farms were randomly selected to be investigated. Multiplex PCR showed all isolated colonies were Prototheca bovis. Performing RAPD-PCR by using OPA-4 primer, it was revealed that there was a clear amplification pattern. Different levels of biofilm production were observed among strains. Among 48 isolates, only 4 of them (8.33%) showed strong biofilm production. By using E-test strips, amphotericin B was able to inhibit the growth of all the strains tested. Disc diffusion method used for antimicrobial sensitivity test showed that the highest activity was demonstrated by gentamicin and colistin with 95.83% (46/48) and 89.58% (43/48) of sensitive strains, respectively. Conclusions The present study showed that RAPD-PCR was a rapid tool for discriminating P. bovis strains. Also, gentamicin and colistin can be considered as potential antimicrobial drugs which can prevent the growth of the mentioned strains in vitro, although there is no effective clinical treatment yet. Further studies are needed in order to detect an effective clinical therapy considering biofilm production by Prototheca spp. and their probable role in Prototheca pathogenicity.

Milk Microbiota of Clinical Mastitic Cows: An Etiological Approach

“…A recent taxonomic reclassification of the algae in 14 species has been proposal based on mitochondrial cytB gene, where P. bovis and, less frequently, P. blaschkeae, are recognized as the main algae-related bovine mastitis species worldwide [43], including in Brazil [44,45]. Nonetheless, to date, none therapeutic protocol has been considered effectiveness to treat protothecal mammary infections [46], which has motivated a set of in vitro studies evaluating the algaecidal effect of different compounds, including antimicrobials, antifungal, sanitizer, natural extracts, essential oils, nanoparticles, and herbicides [44,47,48]. In the current study, 2.6% of cultured milk samples revealed isolation of the genus Prototheca, a fact that is concerning, due to absence of specific treatment approaches and, at this moment, the control [42,43] measures against this alga have been restrict to segregation, chemical dry of quarters, and culling of infected cows [42,43,48].…”

Prototheca spp. in Bovine Infections

“…P. bovis is reported to be capable in biofilm production [11,12]. This polymeric matrix is produced by other organisms causing mastitis, such as bacteria and fungi.…”

“…Conventional antimycotic drugs were in vitro checked against P. bovis [109, [113][114][115], with amphotericin B considered quite efficient, also in the presence of biofilm-producing P. bovis strains [12]. However, in a multicentric study, involving 144 isolates of P. bovis and P. blaschkeae, strong differences in sensitivity to amphotericin B and some azoles were reported based on the geographic source of strains [114].…”

“…Prototheca spp. can produce biofilm [11,12]. Bovine mammary gland can be infected by P. bovis following teat trauma by mechanical milking, and subsequent contamination of the teat orifice by environmental organic matter [13,14].…”

Investigation of Prototheca bovis Infection and Its Correlation with Dairy Herd Improvement Data from a Dairy Farm in Central China

“…The algae thrive in warm, humid environments where there is plentiful organic matter, such as forage, bedding materials, and cattle feces, which has resulted in the frequent infection of dairy cows [ 7 ]. In addition, recent studies showed that P. bovis isolates are susceptible to several antibiotics and antifungal drugs in vitro, but no effective clinical treatment is currently available, making prevention and treatment more difficult [ 8 , 9 ].…”