Mastitis-affected Cows Research Articles

Analysis of the Somatic Cell Pattern in Mastitis - Affected Cows on Three Dairy Farms in Vojvodina

Summary Somatic cells (SCs) in milk, which include epithelial cells from the gland and blood cells, are present in milk during the normal course of milking. Increase in SCs is found in mastitis-affected dairy cows and can be a useful indicator for estimating mammary health and milk quality worldwide. The aim of this study was to determine whether there was a pattern of somatic cell count (SCC) in mastitis-affected cows on three different farms. The study was conducted on three dairy farms of high milk-producing cattle breeds in Vojvodina during 2021. Samples were taken from 15 cows from each farm, all of the cows being diagnosed with clinical and subclinical mastitis. The SCC in milk samples was determined by the microscopic reference method according to the standard (SRPS EN ISO 13366-1:2010) of the Institute for Standardization of Serbia. The value of SCC was considered as high if >200.000 cells/mL, as this is the threshold indicating secretion disorder. In order to examine the differences between the observed three farms, one-factor analysis of variance (ANOVA) was applied, while a post-hoc LSD test was used for determination of statistically significant differences between the SCC in cows on three different farms. The mean values of the SCC on Farms 1, 2 and 3 were 7,055,266.67, 2,619,893.33 and 552,000 cells/mL, respectively. Based on the results, a statistically significant difference (p<0.05) was established between Farms 1 and 2, as well as between Farms 1 and 3, while there was no statistically significant difference between Farms 2 and 3. Apart from mastitis, differences in the SCC on the farms could also be influenced by the cows’ productivity, parity, lactation stage and breed, as well as poor management practices. Besides mastitis control, better hygiene and proper nutrition can help in reducing SCs in milk. In conclusion, establishing SCs pattern can provide useful information that may contribute to reducing SCs and developing differential SCs standards to help obtain milk with low SCs and consequently better dairy products with a longer shelf life.

Assessment of Mastitis Patterns in Serbian Dairy Cows: Blood Serum Metabolic Profile and Milk Composition Parameters.

Mastitis is one of the most important diseases in dairy cows, leading to substantial economic losses associated with decreased milk production and quality. Early detection of changes in metabolic and milk parameters is crucial for maintaining animal welfare and milk quality. This study aimed to detect patterns in metabolic and milk composition parameters in Serbian dairy cows affected by mastitis. It also examined the relationship between these factors in cows with clinical and subclinical mastitis, as well as in healthy cows. This study included 60 Holstein-Friesian cows with the same body score condition that were in the same lactation phase. They were divided into three groups of 20: clinical and subclinical mastitis and a control group of healthy cows. The categorization was based on clinical udder health and the California mastitis test. Blood serum metabolic profiles were measured using a Rayto spectrophotometer (Shenzhen, China), and milk composition was determined using MilcoScanTM (Foss, Hilleroed, Denmark) and FossomaticTM (Foss, Hilleroed, Denmark) instruments. Significant increases in non-esterified fatty acids (NEFAs), beta-hydroxybutyrate (BHB), total protein, globulin, urea, total bilirubin, magnesium, and enzyme activity were noted in mastitis-affected cows compared to healthy ones. Additionally, mastitis-affected cows had higher total protein and globulin levels and increased somatic cell counts (SCCs), while albumin concentrations were decreased. Furthermore, a negative correlation between total protein and lactose suggested inflammation leading to reduced lactose levels due to cell damage, infection, and lactose use by mastitis pathogens. Hence, indicators of the energy and protein status of the metabolic profile, together with the chemical composition of milk, may be significant diagnostic tools for detecting, monitoring, and predicting the outcome of mastitis in cows.

Metataxonomic analysis of milk microbiota in the bovine subclinical mastitis.

Subclinical mastitis is one of the most widespread diseases affecting dairy herds with detrimental effects on animal health, milk productivity, and quality. Despite its multifactorial nature, the presence of pathogenic bacteria is regarded one of the main drivers of subclinical mastitis, causing a disruption of the homeostasis of the bovine milk microbial community. However, bovine milk microbiota alterations associated with subclinical mastitis still represents a largely unexplored research area. Therefore, the species-level milk microbiota of a total of 75 milk samples, collected from both healthy and subclinical mastitis-affected cows from two different stables, was deeply profiled through an ITS, rather than a traditional, and less informative, 16S rRNA gene microbial profiling. Surprisingly, the present pilot study not only revealed that subclinical mastitis is characterized by a reduced biodiversity of the bovine milk microbiota, but also that this disease does not induce standard alterations of the milk microbial community across stables. In addition, a flow cytometry-based total bacterial cell enumeration highlighted that subclinical mastitis is accompanied by a significant increment in the number of milk microbial cells. Furthermore, the combination of the metagenomic and flow cytometry approaches allowed to identify different potential microbial marker strictly correlated with subclinical mastitis across stables.

Метаболические особенности и микрофлора молока при маститах у коров Амурской области

The effective management practices of dairy farming are inextricably linked with the production of high quality milk, while the mastitis is one of the causes of reductions in milk yields and quality. The aim of the work was to study the microbiological profile of milk, the sensitivity of isolated microorganisms to antibiotics and metabolism features of cows with mastitis in the Amur Oblast. The following microorganisms were identified in the milk samples from cows with mastitis: Staphylococcus epidermidis (34.69%); microbial associations: Streptococcus agalactiae + Escherichia coli (32.65%) and Staphylococcus saprophyticus + Streptococcus agalactiae + Escherichia coli (30.61%); Staphylococcus haemolyticus (2.05%). Microorganisms isolated from the milk of mastitis-affected cows were susceptible to the following antimicrobials: Escherichia coli to cefotaxime (28.00 ± 2.00 mm) and ceftriaxone (27.50 ± 0.35 mm); Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus saprophyticus to cefotaxime (35.50 ± 0.18 mm) and amoxicillin (35.10 ± 0.35 mm); Streptococcus agalactiae to tetracycline (27.60 ± 1.17 mm) and gentamicin (26.40 ± 0.99 mm). Metabolic disorders were observed in cows with mastitis. The albumin-globulin ratio was reduced (0.41), which is typical for various inflammatory processes; and a low albumin levels (29.00 ± 0.89%) suggested a decreased protein synthesis in hepatocytes. A moderate increase in gamma globulins (47.60 ± 1.05%) was associated with stimulation of the phagocytic mononuclear system. Water and mineral metabolism disorders were confirmed by low levels of calcium (1.80 ± 0.03 mmol/L) and magnesium (0.70 ± 0.02 mmol/L), which is a sign of many pathological conditions, and is associated with heavy lactation. Calcium-phosphorus ratio was reduced (0.82). Hematological indicators suggested hypochromic anemia (hemoglobin level – 100.60 ± 1.28 g/L, globular value – 0.60 ± 0.01). The leukogram was indicative of lymphocytopenia (36.90 ± 2.60%) and neutrophilia (rod-shaped neutrophils – 1.80 ± 0.13%, segmented neutrophils – 51.80 ± 2.51%).

Studi Kasus: Jumlah Sel Somatik dan Komposisi Susu dari Sapi Perah Positif Mastitis Subklinis Milik PT. Great Giant Livestock

An increase in the number of somatic cells to more than 400.000 cells/mL and the presence of pathogenic bacteria in the milk during normal lactation are two characteristics of subclinical mastitis. The purpose of this study was to compare subclinical mastitis-positive cows with healthy cows in terms of somatic cells count and milk composition, as well as the relationship between these two variables. Acquire from PT. Great Giant Livestock, a total of 29 fresh milk samples from 9 dairy cows tested positive for subclinical mastitis. The Breed method was used to determine the somatic cell count. Lactoscan was used to count the milk composition including fat, protein, lactose, solid non-fat, total solids, and density. The correlation between the somatic cell count and milk quality was tested using the Rank Spearman and the differences in milk quality between healthy cows and subclinical mastitis-positive cows were analyzed using Mann Whitney U. According to the data, subclinical mastitis-positive cows had more somatic cells than healthy cows. Furthermore, subclinical mastitis-affected cows provide milk of lower quality. Dairy cows with subclinical mastitis and healthy cows had significantly different milk composition (p< 0,05). The correlation between the number of somatic cells and milk composition was highly significant (p< 0,05). Subclinical mastitis-positive cows have a higher number of somatic cell and lower milk composition compared to healthy cows. The somatic cells count has a relationship with the composition of milk.

Effect of anemoside B4 on milk whey in clinical mastitis-affected cows elucidated using tandem mass tag (TMT)-based quantitative proteomics

Intramuscular injection of anemoside B4 (AB4) has a superior therapeutic effect on clinical mastitis in lactating cows. Here, we explored AB4’s effect on milk whey in clinical mastitis-affected cows using proteomics. Among fifty clinical mastitis cows received AB4 administration (0.05 ml/kg/day, for 7 days), twelve healed cows were selected and marked as group T. Twelve clinically heathy cows received the same dose of saline for 7 days, marked as group C. Collected milk whey of group T before and after AB4 administration marked as T1 and T2, respectively. The milk whey of group C after saline injection marked as C1. Milk whey protein changes were detected using tandem mass tag-based quantitative proteomic. We identified 872 quantifiable proteins in the samples. Among them, 511 proteins between T1 and C1, and 361 proteins between T2 and T1 were significantly altered. T1 than C1 had significantly more proteins associated with inflammatory damage and trans-endothelial migration of leukocytes, whereas these proteins were reduced in T2 treated with AB4. Compared with C, proteins associated with fibrin clot degradation and complement system activation were downregulated in T1 but upregulated in T2. In summary, AB4 can exert its therapeutic effect on clinical mastitis in cows mainly by reducing inflammatory damage, activating the complement system, inhibiting trans-endothelial migration of leukocytes, and promoting degradation of milk fibrin clots.

Expression of anti-inflammatory markers IL-2, IL-10, TGF-β1, βDEF-2, βDEF-3 and Cathelicidin LL37 in dairy cattle milk with different health status of the udder.

Great economic losses to the dairy industry are associated with bovine mastitis, which results in poor milk quality and high treatment costs. Anti-inflammatory proteins play an important role in the suppression of the immune response against invading pathogenic microorganisms and are therefore being studied for possible use in the early diagnosis of mastitis. In our study, we used milk samples from 15 cows of Holstein Friesian breed with different health status (5 healthy, 5 subclinical, and 5 clinical animals), and tested them using immunohistochemical (IHC) analysis to evaluate the presence of IL-2, IL-10, TGF-β1, βDEF-2, DEF-3, and Cathelicidin LL37 proteins. The calculation of positively and negatively stained cells for each biomarker was performed using the semiquantitative counting method. We found the presence of all factors with the exception of Cathelicidin LL37, which was almost absent in milk samples of all animal groups. The significant decrease of IL-10, β-def2, and β-def3 expression levels within the 3 days of sampling, found in the milk of animals with sub- and clinical mastitis, indicates the loss of antiinflammatory protection of the affected cow's udder. In contrast, the stable increase of IL-2 and TGF-β1 positive cells observed in the milk of mastitis-affected cows, and the similar expression of these factors in the milk of healthy animals, indicate the possible lack of involvement of these cytokines at an early stage of udder inflammation.

Expressions of IL4, IL10, and IFNγ cytokines genes during bacterial mastitis.

Objective:Many bacteria are involved in causing mastitis in dairy cows. Perfect identification of bacteria is crucial for the appropriate choice of drug for treatment. This study aims to find out the various bacteria that cause mastitis through the 16S ribosomal ribonucleic acid (16S rRNA) gene.Materials and Methods:A total of 150 mastitis somatic cell samples were tested with bacterial nested polymerase chain reaction (PCR) universal primers, targeting the 16S rRNA gene. The primers had both Gram-positive and Gram-negative bacterial specificities. Inflammatory cytokine interleukin (IL-10), IL-4, and interferon-gamma (IFNγ) expression genes were measured and compared in mastitis-free and mastitis-affected animals.Results:Based on the PCR, 70 (46.7%) samples showed positive results. The expression of the IL-10 gene was significantly higher (p < 0.001) in mastitis-affected cows than noninfected animals. Compared to cows diagnosed with clinical mastitis, the IL-4 and IFNγ genes were expressed more strongly in healthy cows (p> < 0.0001).Conclusion:Mastitis has been linked to both Gram-positive and Gram-negative bacteria. These genes are strong predictors of mastitis in the states analyzed, as evidenced by the differential expression in mastitis and healthy conditions of the IL-4, IL-10, and IFNγ genes. The genes examined here and others will be the subject of additional research.

Early metabolic profiling in the periparturient period reduces the occurrence of postparturient metabolic diseases in cows.

Objective:To study the impact of early metabolic profiling and intervention measures in the periparturient period on the occurrence of postparturient metabolic diseases in cows.Materials and Methods:Using a cohort of dairy cows from two selected areas of Bangladesh, we routinely tested the serum calcium level and ketone bodies in the urine at periparturient periods. In addition, milk samples were tested for the presence of mastitis at different stages of lactation. Animals showing reduced serum calcium levels, high ketone bodies in the urine or the presence of clinical and subclinical mastitis received appropriate therapeutic intervention immediately after detection. After the intervention, the number of animals that got sick with diseases or conditions like milk fever, ketosis, mastitis, and dystocia, which are caused by metabolic problems, was recorded.Results:In the periparturient period, most of the animals had lower serum calcium levels (8.13 ± 1.2 mg/dl), which were significantly increased by the following intervention (10.05 ± 1.4 mg/dl). On the other hand, there was a higher number of ketosis-affected animals (33.9%, 20/59) during the periparturient period, which decreased (18.6%, 11/59) during the postparturient period. Similarly, the number of mastitis-affected cows was also decreased in postparturient cows (30.9%, 13/42) than in periparturient cows (59.5%, 25/42), following improved hygienic measures. After early intervention, the number of study animals with metabolic diseases decreased from 51.7% before intervention to 15.3% after intervention.Conclusions:Early metabolic profiling significantly reduced the occurrence of metabolic diseases in cows. Therefore, we recommend regular metabolic profiling of dairy cows and receiving early intervention measures to reduce the occurrence of metabolic diseases on the farm.

New Perspective of Origanum vulgare L. and Satureja montana L. Essential Oils as Bovine Mastitis Treatment Alternatives.

Mastitis represents a heavy burden for the dairy sector worldwide with high economic and animal welfare impact. Antibiotic treatment is an important component of mastitis control programs. However, emergence and transfer of antimicrobial-resistant (AMR) bacteria is becoming a growing concern. Therefore, the development of novel agents is required for prevention and treatment of mastitis. Hence, our aim was to assess the antibacterial properties of two essential oils (EOs) obtained from oregano (Origanum vulgare L., Lamiaceae) and mountain savory (Satureja montana L., Lamiaceae) against mastitis-associated bacteria in Serbia. The chemical composition and antioxidant potential of these EOs were also evaluated. The present study was conducted on strains derived from aseptic milk samples collected from Holstein-Friesian cows with clinical or subclinical mastitis, during the morning milking. Clinical mastitis was assessed by clinical examination, while subclinical mastitis was confirmed using somatic cell count in the milk samples. The microdilution method was used to determine the antibacterial activity, while antioxidant potential of the EOs was evaluated in several in vitro assays. The values of minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) were used to quantitatively measure the antibacterial activity of each EO. MIC/MBC ranged from 0.78/6.25 and 0.39/0.78 mg/mL for oregano and mountain savory, respectively. A total of 25 compounds were identified in the oregano EO, while 47 were identified in winter savory EO, among which aromatic oxygenated monoterpenes were the most abundant compounds. The tested EOs have shown promising antimicrobial activity and could be considered as one of the treatment approaches in mastitis-affected cows.

Effect of Anemoside B4 on Milk Whey in Clinical Mastitis-Affected Cows Elucidated Using Tandem Mass Tag (TMT)-Based Quantitative Proteomics

Effect of Anemoside B4 on Milk Whey in Clinical Mastitis-Affected Cows Elucidated Using Tandem Mass Tag (TMT)-Based Quantitative Proteomics

Correction: Prevalence and Characterization of Oxacillin Susceptible mecA-Positive Clinical Isolates of Staphylococcus aureus Causing Bovine Mastitis in India.

[This corrects the article DOI: 10.1371/journal.pone.0162256.].

Identification of single nucleotide variations in the Toll-like receptor 9 (TLR9) gene and its association to mastitis susceptibility in dairy cattle

ABSTRACTToll-like receptors (TLRs) play a significant role in the host immune response. The TLR9 recognizes CpG DNA of bacteria and stimulate both the innate and adaptive immune responses. In the present study, functional domain (LRR) of TLR9 gene of mastitis-affected cows in comparison to apparently healthy animals was analyzed for any nucleotide variation as it may influence host susceptibility to disease conditions. LRR domain of TLR9 was amplified and analyzed for single-strand conformational polymorphism (SSCP). Samples shown altered SSCP mobility pattern were sequenced. Three nucleotide variations each in the two regions of functional domain were identified and the one corresponding to G→C variation at position 2318 of reference sequence (Accession No. AJ509824), suggesting the possible association with mastitis. Though the nucleotide variation did not result in amino acid change, it created an additional restriction site for Hae III which can be utilized in developing a new polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) marker.

Analysis of hard protein corona composition on selective iron oxide nanoparticles by MALDI-TOF mass spectrometry: identification and amplification of a hidden mastitis biomarker in milk proteome.

Surface active maghemite nanoparticles (SAMNs) are able to recognize and bind selected proteins in complex biological systems, forming a hard protein corona. Upon a 5-min incubation in bovine whey from mastitis-affected cows, a significant enrichment of a single peptide characterized by a molecular weight at 4338Da originated from the proteolysis of aS1-casein was observed. Notably, among the large number of macromolecules in bovine milk, the detection of this specific peptide can hardly be accomplished by conventional analytical techniques. The selective formation of a stable binding between the peptide and SAMNs is due to the stability gained by adsorption-induced surface restructuration of the nanomaterial. We attributed the surface recognition properties of SAMNs to the chelation of iron(III) sites on their surface by sterically compatible carboxylic groups of the peptide. The specific peptide recognition by SAMNs allows its easy determination by MALDI-TOF mass spectrometry, and a threshold value of its normalized peak intensity was identified by a logistic regression approach and suggested for the rapid diagnosis of the pathology. Thus, the present report proposes the analysis of hard protein corona on nanomaterials as a perspective for developing fast analytical procedures for the diagnosis of mastitis in cows. Moreover, the huge simplification of proteome complexity by exploiting the selectivity derived by the peculiar SAMN surface topography, due to the iron(III) distribution pattern, could be of general interest, leading to competitive applications in food science and in biomedicine, allowing the rapid determination of hidden biomarkers by a cutting edge diagnostic strategy. Graphical abstract The topography of iron(III) sites on surface active maghemite nanoparticles (SAMNs) allows the recognition of sterically compatible carboxylic groups on proteins and peptides in complex biological matrixes. The analysis of hard protein corona on SAMNs led to the determination of a biomarker for cow mastitis in milk by MALDI-TOF mass spectrometry.

The Effect of Some Natural Essential Oils Against Bovine Mastitis Caused by Prototheca zopfii Isolates In Vitro

The aim of the study was to evaluate the effect of essential oils obtained from Thymus vulgaris L., Origanum vulgare L., Origanum majerana L., Mentha × piperita L. and Allium ursinum L. against Prototheca zopfii strains that cause inflammation of the udder (mastitis) in cows. The study was conducted on ten strains derived from milk samples. The microdilution method was used to determine the sensitivity of P. zopfii strains to the studied essential oils, and the disk diffusion method was used to determine the sensitivity to antifungal chemotherapeutics. The plates were incubated for 48 h at 37 °C under aerobic conditions. All strains of algae were sensitive to the essential oils marjoram, thyme and oregano and resistant to mint and garlic oils. MIC values ranged from 0.25 to 1 μl/ml. Marjoram oil demonstrated the greatest activity, and oregano oil the weakest. Among the antifungal agents tested, 90% of strains showed sensitivity to nystatin. One of the tested strains (71/IV) was resistant to all investigated antifungal agents. The tested essential oils are known to have anti-algae activity and can be used as natural agents for prophylaxis in animals, particularly in mastitis-affected cows.

Rapid Communication: MiR-92a as a housekeeping gene for analysis of bovine mastitis-related microRNA in milk.

Our aim was to identify a suitable microRNA housekeeping gene for real-time PCR analysis of bovine mastitis-related microRNA in milk. We identified , , and as housekeeping gene candidates on the basis of previous Solexa sequencing results. Threshold cycle (CT) values for , , and did not differ between milk from control cows and milk from mastitis-affected cows. NormFinder software identified as the most stable single housekeeping gene. We evaluated the suitability of the housekeeping gene candidates by using them to assess expression levels of the inflammation-related gene . Regardless of the housekeeping gene candidates used for normalization, relative expression levels of were significantly higher in mastitis-affected samples than in control samples. However, of all the housekeeping genes and gene combinations investigated, normalization with alone generated the difference in relative expression between mastitis-affected and control samples with the highest significance. These results suggest that is suitable for use as a housekeeping gene for analysis of bovine mastitis-related microRNA in milk.

Characterization of Haptoglobin Isotype in Milk of Mastitis-Affected Cows.

Haptoglobin is a major acute phase protein in bovines and reportedly increases in serum and milk whey during mastitis, highlighting its potential as a diagnostic biomarker. Since haptoglobin is known to undergo tissue specific glycosylation resulting in different isoforms, this study was undertaken to characterize the isoforms of haptoglobin. Milk whey fraction and serum obtained from animals with or without clinical mastitis in Puducherry, India, were subjected to SDS-PAGE followed by western blot and immuno-detection of haptoglobin protein. All subunits (β, α1 and α2) of haptoglobin protein were detected in serum sample obtained from clinical cases. However, only the β-subunit was detected in milk whey fraction obtained from the respective animals. Similar results were observed with milk whey fractions from subclinical cases indicating difference in isoform of haptoglobin detected in milk whey from serum. This was further supported by RT-PCR (Reverse Transcription Polymerase Chain Reaction) analysis of haptoglobin gene (Hp) confirming the tissue specific origin of haptoglobin.

Prevalence and Characterization of Oxacillin Susceptible mecA-Positive Clinical Isolates of Staphylococcus aureus Causing Bovine Mastitis in India.

Bovine mastitis caused by multidrug resistant Staphylococcus aureus is a huge problem reported worldwide, resulting in prolonged antibiotic treatment and death of livestock. The current study is focused on surveillance of antibiotic susceptibility along with genotypic and phenotypic characterization of the pathogenic S. aureus strains causing mastitis in India. One hundred and sixty seven milk samples were collected from mastitis-affected cows from different farms in India resulting in thirty nine isolated S. aureus strains. Antibiotic sensitivity profiling revealed the majority of the strains (n = 24) to be multidrug resistant and eleven strains showed reduced susceptibility to vancomycin (MICs = 2μg/ml). All strains were oxacillin sensitive, but 19 strains were positive for the mecA gene, which revealed the occurrence of oxacillin susceptible mecA positive strains (OS-MRSA) for the first time from India. Additionally, 32 strains were positive for the pvl gene, a virulence determinant; of these 17 were also OS-MRSA strains. Molecular characterization based on multilocus sequence typing (MLST), spa typing, agr typing and SCCmec classification revealed strains belonging to different groups. Moreover, strains showed spa types (t2526, t9602) and MLST sequence types, ST-72, ST-88 and ST-239 which have been earlier reported in human infections. The prevalence of OS-MRSA strains indicates the importance of including both the genetic and phenotypic tests in characterizing S. aureus strains. Increased genotypic variability with strain related to human infections and pvl positive isolates indicates a worrisome situation with the possibility of bilateral transfer.

Characterisation of Pseudomonas aeruginosa related to bovine mastitis

Pseudomonas aeruginosa is one of the causative pathogens of bovine mastitis. Most P. aeruginosa strains possess the type III secretion system (TTSS), which may increase somatic cell counts (SCCs) in milk from mastitis-affected cows. Moreover, most of P. aeruginosa cells can form biofilms, thereby reducing antibiotic efficacy. In this study, the presence and effect of TTSS-related genotypes on increase of SCCs among 122 P. aeruginosa isolates obtained from raw milk samples from mastitis-affected cows and their antibiotic susceptibility at planktonic and biofilm status were investigated. Based on the presence of TTSS-related genes a total of 82.7% of the isolates were found to harbour exoU and/or exoS genes, including the invasive (exoU-/exoS+, 69.4%), cytotoxic (exoU+/exoS-, 8.3%) and cytotoxic/invasive strains (exoU+/ exoS+, 5.0%). Milk containing exoS-positive isolates had higher SCCs than those containing exoS-negative isolates. The majority of isolates showed gentamicin, amikacin, meropenem and ciprofloxacin susceptibility at planktonic status. However, the susceptibility was decreased at the biofilm status. Based on minimum biofilm eradication concentration (MBEC)/minimum inhibitory concentration (MIC) ratios, the range of change in antibiotic susceptibility varied widely depending on the antibiotics (from ≥ 3.1-fold to ≥ 475.0-fold). In conclusion, most P. aeruginosa isolates studied here had a genotype related to increase in SCCs. The efficiency of antibiotic therapy against P. aeruginosa-related bovine mastitis could be improved by analysing both the MBEC and the MIC of isolates.

Antimicrobial susceptibility of Prototheca zopfii isolated from bovine mastitis

Abstract The aim of the study was to evaluate the susceptibility of algae of the genus Prototheca to antifungal and antibacterial antibiotics. The study involved 27 isolates of Prototheca zopfii obtained from milk of mastitis-affected cows kept in a detached cowshed in the North-Eastern part of Poland. Analysis of P. zopfii susceptibility has demonstrated low effectiveness of both antifungal and antibacterial antibiotics. All algae isolated from milk were resistant to clotrimazole, fluconazole, econazole, flucytosine, cefoperazone, cephalexin, enrofloxacin, lincomycin, and oxytetracycline (100% of resistant isolates), as well as miconazole (92.6% of resistant isolates). Nystatin, ketoconazole, and amphotericin B showed the highest activity amongst the antifungal antibiotics (88.9% and 0.0%, 51.9% and 22.2%, 0.0% and 48.1% of susceptible and intermediate susceptible isolates, respectively). In the group of antibacterial antibiotics, the high activity against P. zopfii was observed only in the case of gentamicin, kanamycin (96.3% and 92.6% of susceptible isolates, respectively), and polymyxin B (59.3% of susceptible and 33.3% of intermediate susceptible isolates).