Biofilm Formation, Antimicrobial Resistance in Serratia marcescens Isolated from Different Clinical Cases

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Ahmed Abbas Hamza
Mithal KA. Al-Hassani


S. marcescens; Biofilm formation; Antibiotic resistance; 16S rRNA gene


The current study aimed to detect the ability of Serratia marcescens to biofilms formation and antibiotics-resistance isolated from different clinical cases in Iraq. Two hundred Samples were collected from the UTI, burn, and conjunctive. Samples were cultured on MacConkey and blood agar. Isolate was identified according to colony morphology, Gram staining, conventional biochemical interactions, and analysis profile Vitek® 2 compact system. The culture results revealed an overall 20 positive isolates. Targeting the 16S rRNA gene, all positive culture isolates were confirmed as S. marcescens by PCR assay. Biofilm production is one of the virulence factors of S. marcescens using Congo red agar, it was found that 18 (90%) were producing biofilm while 2 (10%) only were not producing biofilm. But at molecular detection targeting the biofilm gene, all positive 20 (100%) isolates were confirmed to have this gene by conventional PCR assay. The detection of an antimicrobial susceptibility test by the Disc diffusion method and the isolates showed that they were susceptible to (Ciprofloxacin, Levofloxacin, Tobramycin, Amikacin, and Gentamicin). In contrast, absolute resistance against (Amoxicillin, Amoxicillin Clavulanic acid, Cephalexin,, Cfazolin, and Loracarbef). The results showed that the bacteria that made up the strong biofilm were more resistant to the antibiotics used in the present study.

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