scholarly journals Subclinical Mastitis Caused by Staphylococcus Aureus: Analysis Cost Benefit of Antibiotic Therapy in Lactating Cows

2007 ◽  
Author(s):  
Luiz Francisco Zafalon ◽  
Antonio Nader Filho ◽  
Soraia Vanessa Matarazzo
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Therapy ◽  
Cost Benefit ◽  
Subclinical Mastitis ◽  
Lactating Cows

Phagocytosis of Staphylococcus aureus by bovine mammary gland macrophages and intracellular protection from antibiotic action in vitro and in vivo

1984 ◽  
Vol 51 (4) ◽  
pp. 513-523 ◽  
Author(s):  
Neil Craven ◽  
James C. Anderson
Keyword(s):  
Staphylococcus Aureus ◽  
Mammary Gland ◽  
Antibiotic Therapy ◽  
Bovine Mammary Gland ◽  
Lactating Cows ◽  
Colony Forming Units ◽  
Subsequent Exposure ◽  
Increased Sensitivity

SummaryMacrophages isolated from the involuted bovine mammary gland were cultured in vitro. Phagocytosis of opsonized Staphylococcus aureus occurred rapidly, but intracellular killing of bacteria was slow. Many intracellular staphylococci survived for up to 4 d exposure to extracellular cloxacillin and emerged from within the macrophages to multiply extracellularly when the antibiotic was inactivated. Rifampicin was significantly more efficient than cloxacillin in killing intracellular S. aureus after 18 h incubation, but it too failed to sterilize the cultures within 3 d. Staphylococci, which had remained viable within macrophages during 20 h incubation with extracellular cloxacillin, showed an increased sensitivity to dilute lysostaphin on subsequent exposure. A 3 d course of intramammary therapy with cloxacillin, commencing simultaneously with an infecting inoculum of ∼108 colony forming units (c.f.u.) S. aureus, apparently eliminated the infection from one quarter of the udders of each of three lactating cows, but bacteria were re-isolated from two cows after a delay of several days. However, when other quarters of the same cows were infected with ∼108 c.f.u. S. aureus which had been phagocytosed by autologous mammary macrophages, similar simultaneous antibiotic therapy failed to affect these infections. The in vitro and in vivo findings indicate the significance of intracellular survival of S. aureus as a factor contributing to failure of antibiotic therapy.

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 Prevalence of methicillin-resistant Staphylococcus aureus and pattern of antimicrobial resistance in mastitis milk of cattle in Chitwan, Nepal

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Asmita Shrestha ◽  
Rebanta Kumar Bhattarai ◽  
Himal Luitel ◽  
Surendra Karki ◽  
Hom Bahadur Basnet
Keyword(s):  
Public Health ◽  
Staphylococcus Aureus ◽  
Antimicrobial Resistance ◽  
Subclinical Mastitis ◽  
World Health ◽  
Dairy Herds ◽  
Microbiological Analysis ◽  
Biochemical Tests ◽  
Methicillin Resistant ◽  
Milk Samples

Abstract Background The threat of methicillin-resistant Staphylococcus aureus (MRSA) exists globally and has been listed as a priority pathogen by the World Health Organization. One of the sources of MRSA emergence is livestock and its products, often raised in poor husbandry conditions. There are limited studies in Nepal to understand the prevalence of MRSA in dairy animals and its antimicrobial resistance (AMR) profile. A cross-sectional study was conducted in Chitwan, one of the major milk-producing districts of Nepal, from February 2018 to September 2019 to estimate the prevalence of MRSA in milk samples and its AMR profile. The collected milk samples (n = 460) were screened using the California Mastitis Test (CMT) and positive samples were subjected to microbiological analysis to isolate and identify S. aureus. Polymerase Chain Reaction (PCR) was used to identify the presence of the mecA gene and screen for MRSA. Results In total, 41.5% (191/460) of milk samples were positive in the CMT test. Out of 191 CMT positive milk samples, the biochemical tests showed that the prevalence of S. aureus was 15.2% (29/191). Among the 29 S. aureus isolates, 6.9% (2/29) were identified as MRSA based on the detection of a mecA gene. This indicates that that 1.05% (2/191) of mastitis milk samples had MRSA. The antibiotic sensitivity test showed that 75.9% (22/29) and 48.3% (14/29) S. aureus isolates were found to be sensitive to Cefazolin and Tetracycline respectively (48.3%), whereas 100% of the isolates were resistant to Ampicillin. In total 96.6% (28/29) of S. aureus isolates were multidrug-resistant (MDR). Conclusions This study revealed a high prevalence of S. aureus-mediated subclinical mastitis in dairy herds in Chitwan, Nepal, with a small proportion of it being MRSA carrying a mecA gene. This S. aureus, CoNS, and MRSA contaminated milk poses a public health risk due to the presence of a phenotype that is resistant to very commonly used antibiotics. It is suggested that dairy herds be screened for subclinical mastitis and treatments for the animals be based on antibiotic susceptibility tests to reduce the prevalence of AMR. Furthermore, future studies should focus on the Staphylococcus spp. to explore the antibiotic resistance genes in addition to the mecA gene to ensure public health.

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