Antimicrobial Resistance and Biofilm Formation of Listeria monocytogenes on Different Surfaces
a,bSankaradoss Elavarasi, bBalasubramanian Ramesh, aKumpati Premkumar and a*Karuppannan Sathiyamurthy
aDepartment of Biomedical Science, Bharathidasan University, Tiruchirappalli- 620024 (India) bDepartment of Biotechnology, Sri Sankara Arts and Science College (Autonomous), Enathur, Kanchipuram-631561 (India) *Corresponding author Email ID - ksathiyamurthy@yahoo.com. Contact Number: 9444581708.
ABSTRACT
Listeria monocytogenes is a major foodborne pathogen capable of forming a biofilm. The objective of this study was to determine biofilm formation by 62 L. monocytogenes isolated from ready-to-eat (RTE) foods in Kanchipuram, Tamil Nadu, India. The biofilm formation was determined by the methods like Christenson’s test tube method, Congo red agar method, and quantification of biofilm on Catheter assay. In addition, the antimicrobial resistance pattern was analyzed against 12 different antibiotics and compared the antimicrobial resistance pattern before and after biofilm production. Out of 62 isolates, only 6 (9.6%) of isolates were found to be strong biofilm producers, followed by 19 (30.6%) isolates were moderate, 17 (27.4%) isolates were weak biofilm producers, and 20 (32.2%) isolates were non-biofilm producers. Based on the result of the tube test method positive biofilm-formed isolates were subjected to Congo red agar plates. Among 42 isolates tested, it was found that 42 (85.7%) isolates formed biofilm. The randomly selected six biofilmproducing L. monocytogenes strains were subjected to biofilm formation on some catheters and the results revealed positive adherence of L. monocytogenes. The antimicrobial resistant pattern was high after biofilm formation. This study exposed that L. monocytogenes have formed biofilm and this condition leads to a serious threat to humans.