Staphylococcus aureus is recognized worldwide as one of the main contagious mastitis agents in cattle and can express a set of antimicrobial resistance genes and virulence-associated genes that explain the wide range of outcomes of intramammary infections. Staphylococcus aureus strains are heterogeneous: their different resistance and virulence patterns, associated with host-level factors and treatment factors, are related to the severity of infection. The aim of this study was to determine phenotypic antibiotic susceptibility, occurrence of selected antimicrobial resistance genes and other virulence genes in 93 S. aureus strains isolated from clinical mastitis in 6 countries: Argentina, Brazil, Germany, Italy, the United States (New York State), and South Africa. These isolates were tested against a total of 16 drugs (amoxicillin-clavulanate, ampicillin, cefazolin, cefoperazone, cefquinome, enrofloxacin, erythromycin, gentamicin, kanamycin, lincomycin, oxacillin, penicillin, rifampin, spiramycin, sulfamethoxazole/trimethoprim, tylosin) by minimum inhibitory concentration (MIC) assay, and examined for the presence of 6 antibiotic-resistance genes (blaZ, mecA, mecC, ermA, ermB, ermC) and 6 virulence-associated genes (scn, chp, sak, hla, hlb, sea) via PCR analysis. The phenotypic results of this study revealed the presence of 19.4% penicillin-resistant strains, whereas 22.6% of the strains were classified as having resistance (5.4%) or intermediate resistance (17.2%) to erythromycin. Most (96.8%) of the isolates were inhibited by cephalosporins, and all were susceptible to amoxicillin-clavulanate. Two strains (1 from Germany, 1 from Italy) were resistant to oxacillin and were positive for mecA. Among the other antimicrobial resistance genes, the most frequently detected was blaZ (46.2%), and 32.3% of the isolates were positive for erm genes: ermC (21.5%) and ermB (10.8%). The most prevalent virulence gene was hla (100%), followed by hlb (84.9%) and sea (65.6%). These results show a low prevalence of antibiotic multidrug resistance in S. aureus isolates, even if the detection of selected antimicrobial resistance genes did not always correspond with the occurrence of phenotypic antibiotic resistance; the immune evasion cluster gene prevalence was quite low in the samples analyzed.
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http://dx.doi.org/10.3168/jds.2019-17141 | DOI Listing |
Curr Microbiol
January 2025
Molecular Biology Laboratory, Department of Microbiology, Science Campus, Alagappa University, Karaikudi, Tamil Nadu, 630003, India.
Antimicrobial resistance (AMR) is an escalating global health concern that results in approximately 700,000 deaths annually owing to drug-resistant infections. It compromises the effectiveness of conventional antibiotics, as well as fundamental medical procedures, such as surgery and cancer treatment. Phytochemicals, natural plant constituents, and biogenic nanoparticles synthesized through biological processes are pharmacological alternatives for supplementing or replacing traditional antibiotics.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
January 2025
National Engineering Research Center of Green Feeds and Healthy Livestock Industry, Hangzhou, 310058, Zhejiang, China.
The widespread use of antibiotics has led to the emergence of multidrug-resistant bacteria, which pose significant threats to animal health and food safety. Host defense peptides (HDPs) have emerged as promising alternatives because of their unique antimicrobial properties and minimal resistance induction. However, the high costs associated with HDP production and incorporation into animal management practices hinder their widespread application.
View Article and Find Full Text PDFJ Infect Dis
January 2025
Department of Infectious Diseases, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia.
Infection with Neisseria gonorrhoeae, the causative agent of gonorrhoea, causes significant morbidity worldwide and can have long-term impacts on reproductive health. The greatest global burden of gonorrhoea occurs in low- and middle-income settings. Global public health significance is increasing due to rising antimicrobial resistance (AMR), which threatens future gonorrhoea management.
View Article and Find Full Text PDFLett Appl Microbiol
January 2025
Department of Veterinary Microbiology, West Bengal University of Animal and Fishery Sciences, 37, K.B. Sarani, Belgachia, Kolkata, West Bengal, India.
The study was conducted to detect the occurrence and phenotypic resistance pattern of ESBL-producing Enterobacteriaceae in livestock using docking based analysis to reveal the classes of antibiotics against which ESBL-producers are active. Rectal swabs from healthy cattle (n=100), goats (n=88), pigs (n=66) were collected from backyard farms in Andaman and Nicober island (India). In total, 304 isolates comprising E.
View Article and Find Full Text PDFJ Coll Physicians Surg Pak
January 2025
Department of Pathology, Peshawar Institute of Cardiology-MTI, Peshawar, Pakistan.
Antimicrobial-resistant bacteria are particularly prevalent in Southeast Asia, mainly due to inadequate infection prevention and control (IPC) and the widespread and uncontrolled use of antibiotics. Pakistan is the third largest low-middle-income country (LMIC) user of antibiotics. Antibiotic consumption increased by 65%, from 800 million to 1.
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