Biochemical and Molecular Analysis ofStaphylococcus aureusClinical Isolates from Hospitalized Patients

Abstract

Staphylococcus aureus is opportunistic human as well as animal pathogen that causes a variety of diseases. A total of 100 Staphylococcus aureus isolates were obtained from clinical samples derived from hospitalized patients. The presumptive Staphylococcus aureus clinical isolates were identified phenotypically by different biochemical tests. Molecular identification was done by PCR using species specific 16S rRNA primer pairs and finally 100 isolates were found to be positive as Staphylococcus aureus. Screened isolates were further analyzed by several microbiological diagnostics tests including gelatin hydrolysis, protease, and lipase tests. It was found that 78%, 81%, and 51% isolates were positive for gelatin hydrolysis, protease, and lipase activities, respectively. Antibiogram analysis of isolated Staphylococcus aureus strains with respect to different antimicrobial agents revealed resistance pattern ranging from 57 to 96%. Our study also shows 70% strains to be MRSA, 54.3% as VRSA, and 54.3% as both MRSA and VRSA. All the identified isolates were subjected to detection of mecA, nuc, and hlb genes and 70%, 84%, and 40% were found to harbour mecA, nuc, and hlb genes, respectively. The current investigation is highly important and informative for the high level multidrug resistant Staphylococcus aureus infections inclusive also of methicillin and vancomycin.

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“…The results of current study are disagreed with studies done by Karmakar et al [9] and Boucher and Corey [12], in which they separately reported that the frequency of MRSA infections increases continuously in hospital-associated infection.…”

“…Karmakar et al [9] mentioned that among 165 samples, 100 strains (60.60%) were isolated from a selective MSA media and then these isolates were identified as S. aureus by different biochemical tests. Gram staining, catalase, coagulase, and thermonuclease were important phenotypic identifying markers of S. aureus.…”

“…This gene resides on the staphylococcal cassette chromosome (SCC). Staphylococcal cassette chromosome is a large genetic mobile element which varies in size and genetic composition among the strains of MRSA [9]. To treat staphylococcal infections, various classes of antibiotics including beta-lactams, glycopeptides, lipopeptide, oxazolidones, aminoglycosides, macrolides, and fluoroquinolones [11].…”

Beta-lactamase Induction in Nosocomial Staphylococcus aureus Strains Cultured from the Nasal Cavity and Wound of Patients

“…Units of β-Lactamase: One unit of β-lactamase is defined as the amount of enzyme that hydrolyzes benzyl penicillin at the rate of 1 µmole/min (Sykes & Nordstrom, 1972;Karmakar, Dua & Ghosh, 2016).…”

Contribution of Protease, Lipase, Hemolysin and Biofilm in Persist of Staphylococcus aureus Isolated from Food Sources

“…Thus in the last decades, staphylococci and their toxins had also emerged as important and potential pathogen for human and animal [3,5]. The success of S. aureus as a pathogen and its ability to cause such a wide range of infections are the result of its extensive virulence factors such as extracellular enzymes and biofilm formation beside toxins [6,7]. lipases produced from S. aureus could increase the rate of food deterioration through their action on lipids causing accumulation of intermediate and end products that change the flavor of foods [8,9].…”