Genotyping of bovine Prototheca mastitis isolates from Poland

Bovine mastitis due to unicellular, achlorophyllous algae of the genus Prototheca is a serious and complex ailment that accounts for high economic losses in the dairy industry. Bovine protothecal mastitis has been almost exclusively associated with only one species Prototheca zopfii. Recently, based on the 18S rDNA sequence analysis, P. zopfii has been divided into three genotypes (1-3), of which P. zopfii genotype 3 has been given the status of a new species Prototheca blaschkeae sp. nov. The aim of this study was to investigate the genotypic composition of the population of P. zopfii bovine mastitis isolates from Poland, according to that threefold classification. Of the 44 isolates tested, 43 (98%) were identified as P. zopfii genotype 2. Only one isolate was assigned to the newly established P. blaschkeae species. These findings clearly show the predominance of the P. zopfii genotype 2 in the etiology of bovine mammary protothecosis in Poland, but also underline the involvement of P. blaschkeae in the disease. The study is the first to provide molecular characterization of Polish P. zopfii mastitis isolates, collected from different regions of Poland.     

Occurrence of Prototheca zopfii, a mastitis pathogen, in milk

Prototheca zopfii was isolated from cow-composite milk and bulk tank milk by a new selective Prototheca enrichment method. Repeated testing of cow-composite milk from individual cows resulted in P. zopfii isolation data indicating a strong statistical correlation of P. zopfii with specific cows. Prototheca sp. were isolated from the milk of 31 of 79 cows in a single herd, and contamination was discounted as the source. Prototheca sp. were also recovered from 28 of 787 bulk tank milk samples from the Eastern U.S.A., and 22 of 69 temperature control milk samples from pooled dairy farm milk from delivery trucks.     

Bacteriological diagnosis with Petrifilm of mastitis pathogens in milk samples from each quarter and bulk milk samples

Three experiments were conducted to evaluate four different Petrifllm products (3M, Neuss) for detection of mastitis pathogens in quarter and bulk milk samples, comparing them to the results of standard microbiological techniques. The aim of experiment 1 was to determine the sensitivity of 3M Rapid Coliform Count Plate in identifying clinical mastitis cases caused by coliform bacteria. Within 12 h of incubation, three times more coliform bacteria could be identified with Petrifilm than with the standard technique. For a valid result, milk samples must be free of contamination. Experiment 2 focused on whether Petrifilm was able to monitor S. aureus on bulk milk level in herds being infected with this pathogen. In relation to the gold standard (combination of both procedures (standard and Petrifilm, prevalence 52%), sensitivity for the standard procedure amounted to 15.4% and to 94% for Petrifilm. In Experiment 3 the combination of several Petrifilm (RUEGG, 2004) was compared with the standard diagnostic technique (gold standard). Sensitivity of the Petrifilm method approached the assumed gold standard to 43% and specificity to 29%. The positive predictive value of 28% showed that both procedures are not directly comparable with each other. Due to the definition of a gold standard, the weaknesses of the classical technique can be interpreted as a disadvantage of the Petrifilm procedure. The strength of the available Petrifilm as mastitis diagnostic tools is the identification of S. aureus and coliform microorganisms, moreover E. coli.     

Occurrence and characterization of methicillin-resistant staphylococci from bovine mastitis milk samples in Finland

Background

Methicillin-resistant staphylococci (MRS) are increasingly being isolated in bovine mastitis. The aim of our study was to evaluate the occurrence of MRS in Finnish mastitis milk samples and characterize the MRS isolates using molecular methods.

Results

Methicillin-resistant S. aureus (MRSA) was a rare finding in bovine mastitis in Finland. Only two out of 135 (1.5%) S. aureus isolates were positive for mec genes. One of these carried mecA and was of spa type t172, SCCmec type IV and ST375, and the other harboured mecC, being spa type t3256, and ST130. MRSA ST375 is common among human MRSA isolates in Finland, but this is the first report in the country of bovine mecC MRSA. In coagulase-negative staphylococci (CoNS) originating from bovine mastitis, methicillin resistance was more common. In the two CoNS collections studied, 5.2% (17/324) and 1.8% (2/110) of the isolates were mecA positive. Eighteen of these were methicillin-resistant S. epidermidis (MRSE), which were divided into 6 separate PFGE clusters. One pulsotype was detected in different parts of the country, indicating clonal spread. Most MRSE (13/18) were of SCCmec type IV, one was of type V and four were non-typeable. Comparison with a human staphylococcal database indicated that bovine MRSE strains were not closely related to human MRSE isolates.

Conclusions

The occurrence of MRS, especially MRSA, in bovine mastitis in Finland was low. Most methicillin-resistant bovine CoNS are MRSE, and we found evidence of a bovine MRSE strain that may spread clonally. This is the first report of a Finnish bovine isolate of MRSA_mecC ST130. The study provides a baseline for further MRS monitoring.     

Prototheca zopfii genotypes isolated from cow barns and bovine mastitis in Japan

This study is the first investigation on Japanese isolates of Prototheca zopfii from bovine mastitis and the cow-barn surroundings by molecular characterization to clarify routes of infection for bovine protothecal mastitis. We performed isolation of Prototheca from cow-barn surroundings (drinking water, sewage and feces) and milk samples from cases of bovine mastitis. Genotypes of the 32 isolates of P. zopfii from cow-barn surroundings and 67 isolates from mastitis were analyzed by genotype-specific PCR assays and restriction fragment length polymorphism (RFLP) assays. All mastitis isolates were identified as P. zopfii genotype 2. Conversely, 29 isolates from cow-barn surroundings were identified as P. zopfii genotypes 1 and 3 isolates as genotype 2, respectively. Given these results, both genotypes of P. zopfii could exist in cow-barn surroundings, but no sites were identified as frequent sources of P. zopfii genotype 2. P. zopfii isolates should thus be further explored with regard to genotype to clarify the reservoir of etiological agents in bovine Prototheca mastitis.     

Bacterial isolation of milk samples submitted from clinical mastitis buffaloes during 2007 to 2016

Tropical Animal Health and Production - The present study determined trends in the isolation of bacterial pathogens in milk samples submitted from clinical mastitis buffaloes at the University...     

Prototheca zopfii mastitis in a herd of dairy cows

Mastitis caused by the colourless alga Prototheca zopfii was diagnosed in 17 of 120 cows in a dairy herd. Infection occurred in animals varying from 3-14 years old and was present in one to four quarters of each cow. Nine cases were associated with clinical mastitis characterised by the presence in milk of flakes or small clots. Somatic cell counts consistent with subclinical mastitis (>500 x 10(3) cells/ml) were recorded in five of the eight remaining cows. Histological examination of udder tissue showed the presence of granulomatous lesions associated with the presence of Prototheca. The problem was identified and controlled by repeated microbiological examination of milk samples from all lactating cows and immediate culling of infected animals. P. zopfii was also recovered from environmental water samples on this farm. It is suggested that infection may have occurred as a result of teat sores caused by trauma from a milking machine, and the tendency for cows to lay down on a race, the surface of which was sometimes flooded by drain water in which Prototheca were present.     

Prototheca zopfii mastitis in a herd of dairy cows

Mastitis caused by the colourless alga Prototheca zopfii was diagnosed in 17 of 120 cows in a dairy herd. Infection occurred in animals varying from 3–14 years old and was present in one to four quarters of each cow.

Nine cases were associated with clinical mastitis characterised by the presence in milk of flakes or small clots. Somatic cell counts consistent with subclinical mastitis (>500 × 10³ cells/ml) were recorded in five of the eight remaining cows.

Histological examination of udder tissue showed the presence of granulomatous lesions associated with the presence of Prototheca.

The problem was identified and controlled by repeated microbiological examination of milk samples from all lactating cows and immediate culling of infected animals.

P. zopfii was also recovered from environmental water samples on this farm. It is suggested that infection may have occurred as a result of teat sores caused by trauma from a milking machine, and the tendency for cows to lay down on a race, the surface of which was sometimes flooded by drain water in which Prototheca were present.     

Detection of virulence-associated genes in Staphylococcus aureus isolated from bovine clinical mastitis milk samples in Guangxi

Staphylococcus aureus is recognized worldwide as a pathogen causing many serious diseases in humans and animals and is one of the most common etiological agents of clinical and subclinical bovine mastitis. The purpose of this study was to determine the presence of genes encoding clfA, fnbA, fnbB, cap5, cap8, hla, hlb, nuc, sea, and tst of S. aureus strains (n?=?39) isolated from bovine clinical mastitis in Guangxi by polymerase chain reaction amplification. The results of the present study indicated that all isolates were found to contain one or more virulence-associated genes. The most frequently encountered genes were fnbA (97?%) and nuc (90?%), followed by hla (85?%) and hlb (82?%), respectively. None of the investigated S. aureus strains harbored fnbB and sea genes. The data in the present study showed a relatively wide distribution of the genes fnbA and nuc among the investigated isolates, indicating that they play an important role on bovine mastitis pathogenesis. The study provides a valuable insight into the virulence-associated genes of this important pathogen.     

N-acetyl-beta-D-glucosaminidase test for screening milk samples for subclinical mastitis.

The use of the N-acetyl-beta-D-glucosaminidase (NAGase) test for detecting subclinical mastitis was investigated in surveys of milk samples from 20 farms. A milk sample was considered to be mastitic if it had a milk cell count above 400,000 cells/ml, and the NAGase test results were graded accordingly. The test gave an average of 16.6 per cent false positives and 2.0 per cent false negatives per herd. It was concluded that the NAGase test could be used as a rapid screening method for selecting suspect samples for further analysis by standard methods.     

The correlation between California mastitis test results and the presence of mastitis pathogens in composite milk samples

Extract

In this, the Ira Cunningham Memorial Lecture, I will not detail all the Professor's achievements. He did so much so well, that I would be hard put to do justice to his record in the time available. What I will do is reflect on his professionalism and on the way he took that professionalism out to work in society.