Molecular Study of Enterotoxins Genes of Staphylococcus aureus Isolated from Patients in Intensive Care Units
Maysaa El Sayed Zaki1, *, Mohamed A. Rizk1, Asmaa O. Bakr2
1 Clinical Pathology Department, Mansoura Faculty of Medicine, Mansoura, Egypt
2 Clinical Pathology Department, Aswan Faculty of Medicine, Aswan, Egypt
Staphylococcus aureus is responsible for healthcare-associated sepsis. Various virulence genes may be responsible for the severity of the outcome of this infection.
Aims & objectives:
Therefore, the aim of the present study was to investigate the prevalence of enterotoxin genes in S .aureus associated with HCA sepsis affecting adult's patients in Intensive Care Units (ICU).
Materials & Methods:
The study is a cross-sectional observational study included 432 patients admitted to intensive care units with Healthcare-Associated Infections (HCAIs). The patients were subjected to blood culture and identification of the isolated bacteria according to the standard microbiological method. Isolates identified as S. aureus were subjected to molecular studies for the detection of meca gene and enterotoxins genes by multiplex Polymerase Chain Reaction (PCR).
Results & Discussion:
Blood culture was positive in 170 of the patients (39.3%). 47 of the blood culture yield S. aureu. Regarding studies of virulence genes in isolated S. aureus, the most frequent genes were seg (61.7%), mecA (46.8%) and sea (42.6%). The less frequent genes were tst and eta 6.4% for each. Analysis of demographic, clinical and virulence genes of isolated S. aureus to HAIs outcome reveals that the virulence genes namely mec, sei and tst of S. aureus were the only significant factors associated with death The distribution of enterotoxigenic genes among MRSA and MSSA shows a significant association between seg and sei genes in MRSA isolates.
The present study highlights the prevalence of enterotoxin genes in isolated S.aureus from patients with hospital-acquired infections in intensive care units in a tertiary hospital. There was high prevalence as about two-thirds of the isolates harbor seg and sea genes in addition to methicillin resistance gene mecA. The fatal outcome of sepsis in those patients was associated with the presence of enterotoxin genes sei and tst. There is a need for screening patients admitted to intensive care units for S. aureus harboring these genes for proper management and application of isolation and contact guidelines of infection control
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