Molecular identification of Prototheca zopfii genotype 2 mastitis isolates and their influence on the milk somatic cell count

Abstract

Algae from the genus Prototheca are the only plant-like microorganisms which can cause inflammation and alterations in the mammary gland. Prototheca mastitis is usually recognized as a chronic and symptomless disease with reduced milk production and a very high somatic cell count. Molecular identification of Prototheca spp. is helpful for the differentiation of pathogenic from non-pathogenic strains which are probably milk contaminants. Genotype-specific PCR assays, based on the 18S rDNA gene sequences, have recently been developed to differentiate three genotypes of Prototheca zopfii, of which Prototheca zopfii genotype 3 was reclassified in a new species: Prototheca blaschkeae. P. zopfii genotype 2 is characterized as the main causative agent of Prototheca mastitis that leads to significant economic losses in primary milk production. The purpose of this study was to give a molecular characterization of Prototheca strains isolated in cases of subclinical and clinical mastitis, as well as to determine the influence of these pathogenic algae on the milk somatic cell count. After microbiological examination, algae from the genus Prototheca were isolated in pure cultures from 1.8% of all tested milk samples, and all 13 (100%) isolates were determined as Prototheca zopfii genotype 2 by a genotype-specific PCR. This study has provided the first molecular identification of Prototheca zopfii genotype 2 in the Republic of Serbia. In the case of subclinical Prototheca mastitis, the somatic cell count was 4,175,244 ± 1,233,685/mL of milk. A distinctly higher somatic cell count (P<0.05) was found in the quarters infected by Prototheca zopfii genotype 2 than in the quarters infected by Staphylococcus aureus, which is the most common mastitis causative agent worldwide. The results from this study support previous observations that P. zopfii genotype 2 is the main causative agent of Prototheca mastitis which leads to a significant increase in the somatic cell count in the milk.

Short communication: Occurrence and persistence of Prototheca zopfii in dairy herds of Korea

“…To the best of our knowledge, the present study is the first to report protothecal mastitis by P. zopfii genotype 2 in Korean dairy herds and that P. zopfii persisted in the farm throughout the study period. The prevalence of P. zopfii in cases of endemic protothecal mastitis ranged from 2 to 15% (Buzzini et al, 2004;Pieper et al, 2012;Shahid et al, 2016;Branko et al, 2017). The rate of infection in mastitic milk samples (15.9%) in our study was higher than those previously reported in China (13.5%; Shahid et al, 2016), Poland (12.6%; Wawron et al, 2013), Canada (5.1%; Pieper et al, 2012), and Serbia (1.8%; Branko et al, 2017).…”

“…Outbreaks of mastitis caused by P. zopfii have been described as a global problem (Ikeda et al, 1985;Buzzini et al, 2004;Jagielski et al, 2011). Prototheca zopfii induces chronic subclinical or clinical mastitis and leads to a reduction in milk production and elevation of SCC in milk (Ricchi et al, 2010;Sharma et al, 2011;Branko et al, 2017). Furthermore, the genus Prototheca does not respond to routine mastitis therapy and the only control measure developed to date involves the elimination of infected cows (Marques et al, 2006).…”

“…The prevalence of P. zopfii in cases of endemic protothecal mastitis ranged from 2 to 15% (Buzzini et al, 2004;Pieper et al, 2012;Shahid et al, 2016;Branko et al, 2017). The rate of infection in mastitic milk samples (15.9%) in our study was higher than those previously reported in China (13.5%; Shahid et al, 2016), Poland (12.6%; Wawron et al, 2013), Canada (5.1%; Pieper et al, 2012), and Serbia (1.8%; Branko et al, 2017). Our findings showed that, although an infected herd was present in only a single farm, the prevalence of P. zopfii in quarter milk samples was high.…”

Prototheca spp. in Bovine Infections

“…Bovine protothecosis is reported to occur worldwide, in the presence of large dairy herds, mostly in tropical and temperate areas [2]. Predisposing factors to protothecosis are reported to be unclean or repeated intramammary infusions, and antibiotic drug treatments in the udder, where Prototheca would act as an opportunistic pathogen favored by antibiotic-induced suppression of the local flora [3][4][5][6][7][8]. Prototheca spp.…”

Prototheca zopfiiGenotype II induces mitochondrial apoptosis in models of bovine mastitis

“…Reported bovine Prototheca zopfii mastitis occurrence ranges from 7.5 to 16.3% [8,9]; however, these reports are predominantly from outbreaks. Although a large proportion (up to 81%) of dairy herds are infected, this pathogen affects a limited proportion of cows (<10%) [10,12]. Cows are often infected intramammarily with P. zopfii following teat trauma during mechanical milking [13] and contamination of the teat orifice with damp organic material [7,14].…”