Detection of ica C gene involved in biofilm formation in methicillin-resistant Staphylococcus aureus ( MRSA ) isolates

__________________________________________ Background : Staphylococcus aureus ( S.aureus ) is one of the gram-positive bacteria that causes a wide range of nosocomial infections. Our present study aimed to investigate


Patients and Methods:
The

Results:
The present study was done at Beni-suef University Hospital from June 2022 to the end of October 2022.than urine (40.0).There was a statistically significant difference between them (P-value=0.001).
Statistics were done using the Chi-square test /*P-value≤ 0.05 is considered significant.
https://ejmr.journals.ekb.eg/ that 68.8% were high biofilm producers, while 10% and 21.2% were intermediate and low biofilm producers, respectively.From the 63 strong and intermediate biofilm producers isolates, we found that 55 specimens had the icaC gene (87.3%).Conclusion: Our study concluded that adherence ability and biofilm production are important for enhancing virulence factors among isolates of S. aureus strains.________________________________________________________________________________ 1. Introduction: S. aureus is one of the most common causes of healthcare and community-acquired infections e.g wound infections, skin ulcers, septicemia, toxic shock and pneumonia.(1) Multidrug-resistant S. aureus (MDRSA) is a severe global concern that is considered a major health problem all over the world.(2) Biofilm formation contributes to more than 80% of all MRSA infections.In a biofilm, bacterial cells are more resistant to traditional antibiotics and immune factors from the host.Biofilm formation by MRSA isolates is an essential virulence factor influencing its persistence in both the environment and the host (3).Biofilm formation is divided into three stages at least: initial attachment, maturation, and dispersal.S. aureus adheres to different surfaces and takes over the host's tissues as the first step in making biofilm.For this purpose, the bacterium expresses several surface adhesins named "microbial surface components."Moreover, the bacterium recognizes adhesive matrix molecules such as fibronectin-binding proteins A and B (finbA and finbB), clumping factors A and B (clfA and clfB), collagen-binding protein (cna), bone sialoprotein binding protein (bbp), and fibrinogen binding protein (fib) (4).The next step is the expression of ica operon and a surface protein known as biofilmassociated protein (bap).The Ica operon produces polysaccharide intercellular adhesin (PIA).Moreover, PIA mediates bacterial cellto-cell adhesion and biofilm formation in S. aureus biofilms.Among the ica genes, ica C, ica A and ica D have shown a significant function in the biofilm formation in S. aureus (5).

Figure 1 :Table ( 2 ) and figure ( 2 )Table 2 :
Figure 1: Distribution of the studied samples according to their sources

Figure 3 :Figure 4 :Figure 5 :
Figure 3: Resistance rate among the S.aureus isolates to the different antibiotics discs

method for the detection of biofilm formation (CRA method):
 Patients One hundred patients with wound infections, abscesses, bedsores, respiratory infections, urinary tract infections and burns were enrolled in this study.A full history was taken regarding age, sex, smoking history, sepsis occurrence, antimicrobial use during hospitalization, and history of DM  Sample collection and transport Samples of blood, sputum and urine, as well as swabs of wound discharge, pus, bed sores, and burned areas, were taken from the cases to test for S.aureus colonization.The samples were transported immediately to the Laboratory of Medical Microbiology and Immunology Department, Faculty of Medicine, Beni-Suef University for further processing.