Comparison of the VITEK® 2 System with Conventional Methods for Species Identification and Antimicrobial Susceptibility Pattern of Staphylococcal Carrier Isolates

Abstract

Staphylococcus aureus, an opportunistic pathogen that inhabits 20% to 70% of human anterior nares and can cause infections, ranging from mild, superficial infections of the skin and soft tissues to severe conditions like sepsis, necrotizing pneumonia and toxic shock syndrome. Healthcare workers are potential asymptomatic nasal carriers, contribute to major infection transmission. The emergence of multidrug-resistant strains necessitates advanced treatment approaches. The study aimed to identify staphylococcal nasal carriers among dental students, and to compare the results obtained from automated identification system, VITEK® 2 with conventional methods for identifying Staphylococcus species and determining antibiotic susceptibility patterns. Anterior nasal swabs were collected from 42 study participants were processed as per standard microbiological culture techniques. All the conventionally identified S. aureus isolates were subjected to a further analysis using an automated VITEK® 2 SYSTEM. Surprisingly, the automated identification system classified all conventionally proven S. aureus isolates as other Staphylococci species (S. epidermidis (60%), S. warneri, and S. lentus), raising concerns about potential misdiagnosis. Overall, there was a 97.5% categorical agreement between VITEK® 2 system and the reference method, with minimal errors (0.8% very major, 0.6% major, and 1.17% minor). These discrepancies underscore the importance of accurate species identification and highlight the necessity for advanced techniques in infection control strategies, emphasizing the potential impact on decolonization decisions.