Detection of Staphylococcus Aureus Among Coagulase Positive Staphylococci from Animal Origin Based on Conventional and Molecular Methods

Abstract

The present study aimed to detect Staphylococcus aureus (S. aureus) among other coagulase positive staphylococci from animal origin by using conventional methods (biochemical tests and latex agglutination) and a molecular method, based on the nuc gene, as the gold standard and to assess the usefulness of these methods. For this purpose, total of 344 staphylococcal isolates were collected and analysed. A total of 156 isolates suspicious for S. aureus were detected by a conventional biochemical method -88 from cows, 18 from goats, 7 from pigs, 17 from poultry, 7 from rabbits and 19 from dogs. The majority of S. aureus strains gave typical biochemical reactions with the exception of 30 (19.2%) and 25 (16%) that were VP negative and weak positive in fermenting mannitol, respectively. Twelve strains were found to be non-haemolytic (7.7%) and four strains did not ferment trehalose (2.6%). Other staphylococci were identified as S. pseudintermedius (n = 103), S. hyicus (n = 23) and the rest were coagulase-negative staphylococci. Latex agglutination test resulted in rapid positive reactions with S. aureus with exception of 5 strains (3.2%) from cow mastitis milk. Positive agglutination reactions were also established with S. pseudintermedius, and S. hyicus. PCR confirmed all strains that were preliminary identified as S. aureus by amplification of 270 bp fragment of nuc gene specific for this species. The atypical reactions in certain strains established in this study have shown that the precise detection of S. aureus from animal origin should be done by combination of conventional and molecular methods.

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“…They found that 100%, 92%, and 84% isolates were positive for catalase, coagulase, and heat-stable nuclease, respectively. The results of present study agreed with Another study done by Rusenova and Rusenov [10] that total of 156 isolates suspicious for S. aureus were detected by a conventional biochemical method. The majority of S. aureus strains gave typical biochemical reactions with the exception of 30 (19.2%) and 25 (16%) that were VP negative and weak positive in fermenting mannitol respectively.…”

“…Such strains have been correlated to life-threatening infections and deaths, predominantly severe skin infections as well as tissue necrosis. Additionally, Rusenova and Rusenov [10] demonstrated that pvl exotoxin kills leukocytes (neutrophils and macrophages) in different mammals (viz. rabbits, cattle, and humans).…”

Detection of Enterotoxin Genes in Staphylococcus Aureus Isolated From Cow Milk

“…These findings were supported our following results, the positivity of Voges-Proskauer were recorded in 18 isolates from raw milk samples and 8 isolates from local pasteurized milk samples (Table2). Higher results were illustrated by Rusenova and Rusenov (2017) who found that 73% of coagulase positive Staphylococcal strains isolated from different animals were Voges-Proskauer positive. This variation may back to level of contamination, number of samples and method of isolation (Fagundes and Oliveira, 2004).…”

Intralaboratory testing of the PCR protocol for molecular genetic identification of bacteria of the genus Staphylococcus spp

“…Цей процес може спростити використання тест-систем, наприклад . Проте різні родини стафілококів можуть мати мінливі або однакові біохімічні ознаки, що унеможливлює повну їх ідентифікацію мікробіологічними методами [8]. MALDI-ToF MS сучасний метод, який пропонують використовувати як новий золотий стандарт, однак його застосування також потребує виділення чистої культури [9,10].…”