scholarly journals Phenotypic and genotypic study on antibiotic resistance and pathogenic factors of Staphylococcus aureus isolates from small ruminant mastitis milk in South of Italy (Sicily)

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Alessio Parco ◽  
Giusi Macaluso ◽  
Maria Foti ◽  
Maria Vitale ◽  
Vittorio Fisichella ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Polymerase Chain Reaction ◽  
Small Ruminant ◽  
Meca Gene ◽  
Small Ruminants ◽  
Tetracycline Resistance ◽  
Chain Reaction ◽  
Toxin Genes ◽  
Pathogenic Factors ◽  
Polymerase Chain

Staphyloccoccus aureus is the major cause of mastitis in small ruminants in the Mediterranean farms causing severe losses to dairy industry. Antibiotic treatment has been the most common approach to control these infections. Aim of this study was to investigate antimicrobial resistance (AMR), virulence factors and biofilm-related genes of 84 Sicilian strains of S. aureus isolated from sheep and goats milk during two different periods δT1 (2006-2009) and δT2 (2013-2015). Kirby Bauer method and Polymerase Chain Reaction (PCR) were utilized to monitor AMR and related genes (mecA, tetK, tetM, ermA, ermC). Moreover, toxin genes (tsst-1, sea-see, seg-sej, and sep) and biofilm genes (bap, ica, sasC) were studied. Twenty-six isolates (30.9%) showed multidrug resistance. The two groups showed similar results with exception for higher values of resistance for tilmicosin and lower for sulfamethoxazole and vancomycin of the second group. MecA gene was detected in one isolate. Tetracycline resistance was higher than 20%, with an increase in δT2 group. Toxin genes were found in 5 isolates (5.9%), belonging of δT2 group, while 57 of isolates (67.8%) showed biofilm related genes. The high presence of multi-resistant isolates suggests the need of more responsible use of antibiotic therapy for the control of these infections.

scholarly journals Detection of Methicillin Resistance in Staphylococcus Aureus by Polymerase Chain Reaction and Conventional Methods: A Comparative Study

2012 ◽  
Vol 4 (02) ◽  
pp. 083-088 ◽  
Author(s):  
Manju M Pillai ◽  
Ragunathan Latha ◽  
Gautam Sarkar
Keyword(s):  
Staphylococcus Aureus ◽  
Polymerase Chain Reaction ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
Disk Diffusion ◽  
Chain Reaction ◽  
Mannitol Salt Agar ◽  
Polymerase Chain ◽  
Conventional Methods ◽  
Phenotypic Methods

ABSTRACT Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen worldwide, which has emerged over the past 30 years as a leading cause of both nosocomial and community-acquired infections. Accurate and rapid identification of MRSA in clinical specimens is essential for timely decision on effective antimicrobial chemotherapy. Aim: The present study was conducted to compare two conventional phenotypic methods, oxacillin disk diffusion (ODD) Aim: The present study was conducted to compare two conventional phenotypic methods, oxacillin disk diffusion (ODD) method and mannitol salt agar (MSA) with oxacillin, with polymerase chain reaction (PCR) for mecA gene (as standard). Materials and Methods: A total of 165 consecutive clinical isolates of S. aureus received at the Department of Microbiology in our tertiary care teaching hospital were included in the study. All the isolates were subjected to ODD (1 μg) method, culture in MSA with oxacillin, and PCR for mecA gene. Results: The sensitivity and specificity of ODD test were found to be 93.5% (86.4-97.3%) and 83.5% (79.2-85.8%), respectively, and that of MSA with oxacillin were found to be 87.1% (79.5-92.3%) and 89.3% (84.8-92.5%), respectively. The time taken for diagnosing MRSA by conventional methods is 48-72 h, which is more as compared to PCR which takes 18-24 h. Conclusion: This study recommends advocating PCR for mecA gene on a regular basis for detecting methicillin resistance in S. aureus isolates isolated from sterile body fluids or from special units such as intensive care units.

Development of a Multiplex Polymerase Chain Reaction Assay for Detection and Differentiation of Staphylococcus aureus in Dairy Products†

2001 ◽  
Vol 64 (5) ◽  
pp. 664-668 ◽  
Author(s):  
SUDHIR TAMARAPU ◽  
JOHN L. McKILLIP ◽  
MARYANNE DRAKE
Keyword(s):  
Staphylococcus Aureus ◽  
Polymerase Chain Reaction ◽  
Multiplex Pcr ◽  
Dairy Products ◽  
Multiplex Polymerase Chain Reaction ◽  
Skim Milk ◽  
Cheddar Cheese ◽  
Polymorphism Analysis ◽  
Chain Reaction ◽  
Polymerase Chain

A multiplex polymerase chain reaction (PCR) assay was developed for the detection and differentiation of enterotoxigenic Staphylococcus aureus in dairy products. A solvent extraction procedure was successfully modified for extraction of S. aureus DNA from 10 ml of artificially contaminated skim milk or 20 g cheddar cheese. Primers targeting the enterotoxin C gene (entC) and thermostable nuclease gene (nuc) were used in the multiplex PCR. PCR products were confirmed using restriction fragment length polymorphism analysis. DNA was consistently quantified and amplified by uniplex PCR from 10 CFU/ml of S. aureus in skim milk or 10 CFU/20 g cheddar cheese. The sensitivity of the multiplex PCR was 100 CFU/ml of skim milk or 100 CFU/20 g cheddar cheese. The developed methodology allows presumptive identification and differentiation of enterotoxigenic S. aureus in less than 6 h.

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