scholarly journals Microbiological and molecular aspects of Staphylococcus aureus isolated from bovine mastitis in West-Central Brazil

2020 ◽  
Vol 14 (1) ◽  
pp. 87
Author(s):  
T. B. Vieira ◽  
R. Almeida ◽  
I. B. Jesus ◽  
F. Freitas ◽  
R. T. Kemper ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Bovine Mastitis ◽  
Subclinical Mastitis ◽  
Enterotoxin Gene ◽  
Central Brazil ◽  
Lactating Cows ◽  
Molecular Aspects ◽  
And Staphylococcus Aureus

Bovine mastitis is a major disease affecting dairy cattle, and Staphylococcus aureus is one of the most important agent involved in this condition due to its capacity to produce enterotoxins and develop resistance to antimicrobial agents. This study aimed to detect S. aureus strains in milk samples from cows with subclinical mastitis employing microbiological and molecular analysis.  Eleven farms were visited and from 187 lactating cows sampled, 33 S. aureus strains were isolated.  Only one of the 33 strains was positive for mecA resistance gene, 23 were positive for sea enterotoxin gene, and none was positive for seb or sec enterotoxin gene. S. aureus strains were submitted to in vitro antimicrobial susceptibility test and 63.6% (21/33) were susceptible to all antimicrobials tested, while 36.3% (12/33) were resistant to one or more antimicrobial agents. Identification of mecA and the sea genes highlighted the need to elaborate strategies to reduce problems related to animal. Furthermore, the identification of bovine mastitis caused by S. aureus is very important to manage herd and to public health, since milk contaminated by this pathogen can lead to serious health problems.

scholarly journals Within-Host Adaptation of Staphylococcus aureus in a Bovine Mastitis Infection Is Associated with Increased Cytotoxicity

2021 ◽  
Vol 22 (16) ◽  
pp. 8840
Author(s):  
Katharina Mayer ◽  
Martin Kucklick ◽  
Helene Marbach ◽  
Monika Ehling-Schulz ◽  
Susanne Engelmann ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bovine Mastitis ◽  
Adaptive Strategy ◽  
Subclinical Mastitis ◽  
Growth Conditions ◽  
Typical Feature ◽  
Host Adaptation ◽  
Bovine Mammary Epithelial Cells ◽  
Strain Pair

Within-host adaptation is a typical feature of chronic, persistent Staphylococcus aureus infections. Research projects addressing adaptive changes due to bacterial in-host evolution increase our understanding of the pathogen’s strategies to survive and persist for a long time in various hosts such as human and bovine. In this study, we investigated the adaptive processes of S. aureus during chronic, persistent bovine mastitis using a previously isolated isogenic strain pair from a dairy cow with chronic, subclinical mastitis, in which the last variant (host-adapted, Sigma factor SigB-deficient) quickly replaced the initial, dominant variant. The strain pair was cultivated under specific in vitro infection-relevant growth-limiting conditions (iron-depleted RPMI under oxygen limitation). We used a combinatory approach of surfaceomics, molecular spectroscopic fingerprinting and in vitro phenotypic assays. Cellular cytotoxicity assays using red blood cells and bovine mammary epithelial cells (MAC-T) revealed changes towards a more cytotoxic phenotype in the host-adapted isolate with an increased alpha-hemolysin (α-toxin) secretion, suggesting an improved capacity to penetrate and disseminate the udder tissue. Our results foster the hypothesis that within-host evolved SigB-deficiency favours extracellular persistence in S. aureus infections. Here, we provide new insights into one possible adaptive strategy employed by S. aureus during chronic, bovine mastitis, and we emphasise the need to analyse genotype–phenotype associations under different infection-relevant growth conditions.

scholarly journals Virulence, agr groups, antimicrobial resistance and epidemiology of Staphylococcus aureus isolated from bovine subclinical mastitis

2021 ◽  
Vol 58 ◽  
pp. e186701
Author(s):  
Felipe Mendes Zorzi ◽  
Luiz Francisco Zafalon ◽  
Franklin Bispo Santos ◽  
Arthur Ferreira Borges ◽  
Ticiano Gomes Nascimento ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Genes ◽  
Antimicrobial Agents ◽  
Subclinical Mastitis ◽  
Southeastern Brazil ◽  
Economic Losses ◽  
Group Iii ◽  
Oxacillin Resistance ◽  
Group Ii

Fifty-two Staphylococcus aureus recovered from papillary ostium and milk samples collected from cows with subclinical mastitis and milking environments in three small dairy herds located in southeastern Brazil were subjected to PCR identification based on the thermonuclease (nuc) gene. All the strains were submitted to in vitro antimicrobial susceptibility testing, and we investigated the sequence types (STs), agr groups (I-IV), virulence genes encoding for Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs), biofilm-associated proteins, bi-component toxins, pyrogenic toxin superantigens, and enterotoxins. Screening for oxacillin resistance (2-6 μg/ml oxacillin), beta-lactamase activity assays, and PCR for the mecA/mecC genes detected 26 methicillin-susceptible S. aureus (MSSA) and 26 mec-independent oxacillin-nonsusceptible S. aureus (MIONSA). While MSSA isolates were found to be susceptible to all antimicrobial agents tested, or only resistant to penicillin and ampicillin, MIONSA isolates were multidrug-resistant. ST126-agr group II MSSA isolates were prevalent in milk (n=14) and carried a broad set of virulence genes (clfA, clfB, eno, fnbA, fiB, icaA, icaD, lukED, hla, and hlb), as well as the ST126-agr group II MIONSA isolated from milking liners (n=1), which also carried the eta gene. ST1-agr group III MIONSA isolates (n=4) were found in papillary ostium and milk, but most MIONSA isolates (n=21), which were identified in both papillary ostium and milking liners, were agr-negative and assigned to ST126. The agr-negative and agr group III lineages showed a low potential for virulence. Studies on the characterization of bovine-associated MSSA/MIONSA are essential to reduce S. aureus mastitis to prevent economic losses in dairy production and also to monitor the zoonotic potential of these pathogens associated with invasive infections and treatment failures in healthcare.

scholarly journals In-Vitro Antibacterial Activity of crude Garlic (Allium Sativum) Extract Against Clinical Isolates of Methicillin Resistant Staphylococcus aureus

2021 ◽  
Vol 14 (3) ◽  
pp. 1449-1457
Author(s):  
Salma Osman Noorelhuda Mohammed ◽  
Nadir Musa Khalil Abuzeid ◽  
Sara Abdelghani ◽  
Lienda Bashier Eltayeb
Keyword(s):  
Staphylococcus Aureus ◽  
Allium Sativum ◽  
Antimicrobial Agents ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Negative Consequences ◽  
Methicillin Resistant ◽  
And Staphylococcus Aureus

Background:Methicillin-resistant Staphylococcus aureus (MRSA) has gained significant health solicitude globallydue to its resistance to nearly almost antimicrobial agents, and garlic is one of nature's most powerful antibiotics that must be used as a pharmaceutical regimen. The current study aimed to determine the In-Vitro antibacterial efficacy of crude garlic extract against MRSA. Methods: The aqueous and 70% ethanol crude garlic (Alllium sativum)extract was prepared. Disc diffusion method was performed to assess the antimicrobial activity for100 clinical isolates of MRSA collected,The reference standard strain was Staphylococcus aureus (ATCC 25923). Results: All MRSA strains assessed were significantly sensitive to 70% ethanolic extract at various concentrations range from 200 to 25%, exhibited inhibitory effects against clinical isolates and Staphylococcus aureus (ATCC 25923) with the means of inhibition zones ranging from 17.76- 14.35 mm and 15-13 mm in length, while the aqueous extracts were less in both clinical isolates and Staphylococcus aureus (ATCC 25923) ranging from 11.93-8.62 mm and 11-8 mm respectively, methanol and distilled water were not effected on growth. Conclusion: The findings demonstrate that 70%ethanol extract of crude Allium sativum has significantly inhibitory effect on methicillin-resistant Staphylococcus aureus is better than aqueous extract. This study does not undermine the value of antibiotic use, but instead the probability of using them in low dosage to minimize their negative consequences.

Isolation of Phages and Study of their In vitro Efficacy on Staphylococcus aureus Isolates Originating from Bovine Subclinical Mastitis

2021 ◽  
Author(s):  
A.S. Srujana ◽  
J. Sonalika ◽  
D.S. Akhila ◽  
M.R. Juliet ◽  
P. Sheela
Keyword(s):  
Staphylococcus Aureus ◽  
Bovine Mastitis ◽  
Subclinical Mastitis ◽  
Global Market ◽  
Host Susceptibility ◽  
Health Concept ◽  
Disk Diffusion Assay ◽  
Potential Strategy ◽  
The One

Background: India leads the global market in milk production. However, bovine mastitis, which is the mammary gland inflammation in dairy cattle characterized by physical, chemical, bacteriological changes in milk results in commercial losses. Staphylococcus aureus, is the major causative agent. The treatment of mastitis caused by this pathogen is mainly by antibiotics. Emphasizing on the one health concept, phage therapy is an appropriate alternative to antibiotic. The present study was aimed to isolate and characterize bacteriophages against Staphylococcus aureus associated with bovine mastitis.Methods: Thirty two isolates of S. aureus obtained from the milk of mastitis cows were characterized by phenotypic and genotypic methods. Antibiotic susceptibility of the isolates was carried out by disk diffusion assay. Milk and cow shed wastewater were used for phage isolation. Phages were characterized by host susceptibility and RAPD assay.Result: Nineteen phages were isolated from the cowshed waste water. All the milk samples showed negative for the presence of phage. The phage 24 (A2) which had the broadest host range, was selected for the CFU drop assay. The phage was able to clear the lawn of S. aureus culture when grown on agar at different time points thus indicating that topical application of this phage would be a potential strategy to control S. aureus infection leading to mastitis. This study provides a basis to continue the exploration of the potential of PSA2 phage as a candidate for the treatment of Staphylococcal mastitis.

Biofilm-formation by Staphylococcus aureus and Staphylococcus epidermidis isolates from subclinical mastitis in conditions mimicking the udder environment

2015 ◽  
Vol 18 (4) ◽  
pp. 787-792 ◽  
Author(s):  
R. Seixas ◽  
D. Varanda ◽  
R. Bexiga ◽  
L. Tavares ◽  
M. Oliveira
Keyword(s):  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Bovine Mastitis ◽  
Subclinical Mastitis ◽  
Protective Role ◽  
Dynamic Conditions ◽  
Biofilm Production ◽  
Static Conditions

AbstractStaphylococcusis the genus most commonly isolated from bovine mastitis in many countries. It may express several virulence factors including biofilm formation, which may protect the bacterial community from antimicrobials’ action, preventing these compounds from reaching its interior, where they reach subinhibitory concentrations (subMIC).Most biofilm production assays are performed in static conditions, while studies regarding antimicrobial resistance usually do not resemble the udder environment because they are performed at high concentrations. In this study we evaluated the influence of dynamic conditions and media, including Mueller Hinton Broth (MHB) and UHT whole milk (WM), as well as the effect of subMIC concentrations of five different antimicrobial agents on biofilm formation by staphylococci isolated from subclinical mastitis. Results suggest that dynamic conditions and media may influence biofilm formation and revealed that milking simulation may significantly increase biofilm production. Sub-MIC concentrations decrease biofilm formation in MHB but increase in WM, suggesting a protective role of milk against antimicrobial compounds’ action. Therefore,in vitroconditions that simulate the udder environment andin vivoconditions should be included as one of the parameters in evaluation of biofilm producing strains, in order to provide more reliable results.

scholarly journals Phenolic Plant Extracts Versus Penicillin G: In Vitro Susceptibility of Staphylococcus aureus Isolated from Bovine Mastitis

2019 ◽  
Vol 12 (3) ◽  
pp. 128
Author(s):  
Fernanda Gomes ◽  
Maria Rodrigues ◽  
Natália Martins ◽  
Isabel Ferreira ◽  
Mariana Henriques
Keyword(s):  
Staphylococcus Aureus ◽  
Plant Extracts ◽  
Antimicrobial Agents ◽  
Juglans Regia ◽  
Bovine Mastitis ◽  
Treatment Plant ◽  
The Other ◽  
Penicillin G ◽  
In Vitro Susceptibility

Antibiotics are the elective drugs in bovine mastitis (BM) treatment, despite their low rates of efficiency and effectiveness and increasing risk of pathogen resistance. In this sense, it is urgent to discover new and effective antimicrobial agents to apply in BM control and even treatment. Plant extracts have been widely recognized as a rich source of phytochemicals with antimicrobial potential. Thus, the present work aims to compare the bioactivity of Eucalyptus globulus and Juglans regia extracts against Staphylococcus aureus bovine mastitis strains with penicillin G. At non-toxic concentrations, E. globulus exerted a bacteriostatic effect in planktonic cells and J. regia had no antimicrobial activity. Penicillin G, at minimum inhibitory concentration (MIC), demonstrated bactericidal activity, but just for S. aureus 3, 5, 6 and ATCC 25923, while the other strains seem to have acquired resistance. On the other hand, E. globulus and penicillin G in combination demonstrated synergy, being the most effective approach against S. aureus 1, 2 and 4. Thus, penicillin alone and in combination with E. globulus or J. regia seems to be promissory strategies to control bovine mastitis infections.

scholarly journals Case Study: Misdiagnosis of Nonhemolytic Staphylococcus aureus Isolates from Cases of Bovine Mastitis as Coagulase-Negative Staphylococci

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 252
Author(s):  
Valerie E. Ryman ◽  
Felicia M. Kautz ◽  
Steve C. Nickerson
Keyword(s):  
Staphylococcus Aureus ◽  
Bovine Mastitis ◽  
Dairy Farm ◽  
Blood Agar ◽  
Coagulase Negative Staphylococci ◽  
Mannitol Salt Agar ◽  
Lactating Cows ◽  
Presumptive Identification ◽  
Microbiological Techniques

Staphylococcus aureus is one of the most concerning mastitis-causing pathogens in dairy cattle. Using basic microbiological techniques, S. aureus is typically identified by colony characteristics and hemolysis on blood agar where isolates without hemolysis are typically considered to be coagulase-negative staphylococci (CNS) isolates. Herein, we present a decade-long case study where suspected S. aureus isolates from one Georgia dairy farm were further tested to confirm presumptive identification. Presumptive identification of bacterial growth from 222 mammary secretions from bred Holstein heifers and lactating cows was conducted at the time of collection. Presumptive identification of S. aureus on blood agar was based on observation of colony morphology, color, and presence or absence of a broad zone of incomplete hemolysis and a smaller zone of complete hemolysis at 48 h. Those without hemolysis were presumptively characterized as CNS. All isolates were further plated on mannitol salt agar and a coagulase test was performed. A positive for both of these tests together was deemed to be S. aureus. A selection of isolates was tested using API® Staph to biochemically confirm S. aureus identification. Data showed that 63.96% of isolates presumed to be CNS isolates were identified as S. aureus, 9.46% of isolates presumed to be CNS isolates were identified as coagulase-positive staphylococci (CPS) species (but not S. aureus), and 26.58% of samples that were presumed to be CNS isolates were identified correctly.

Sign in / Sign up

Export Citation Format

Share Document