Elisa Spinelli,

University of Foggia, Italy



Biography

Elisa Spinelli is a Veterinarian with a Postgraduate qualification in Food safety, Certification and Food Risk Communication. She is a PhD student at University
of Foggia (Italy) where she is working on the main topic of antimicrobial resistant bacteria from a food safety perspective, focusing on the detection and
prevalence of Methicillin resistant Staphylococcus aureus (MRSA) in new ecological niches. She has worked over the last six months as a Visiting PhD student
at The Research Institute of Food Science (CIAL-CSIC), Madrid (Spain) on the fate of MRSA along the human gastrointestinal tract and its interaction with gut
microbiota.

Abstract

Statement of the Problem: Intestinal mucus layer may provide a niche for many nosocomial pathogens, including
S. aureus which can occasionally cause a Staphylococcal enterocolitis. Recent exciting researches support the notion
that a healthy intestinal microbiota composition can promote resistance to invading pathogenic bacterial species.
Purpose: The purpose of this study was to evaluate the survival of MRSA in simulated human ascendant colon
conditions and its interaction with gut microbiota into the mucus layer.
Methodology & Theoretical Orientation: The study was performed at ascendant colon environment: body-like
temperature (37°C), anaerobiosis (N2), pH 5.7, constant slow shaking (40 RPM). Mucin agar carriers stand for the
intestinal mucus layer and a basic feed medium represented the intestinal lumen contents. A three-days long in vitro
study was performed by using microbiota from pooled faeces of healthy individuals that were stabilized simulating
ascendant colon conditions and a MRSA strain of animal origin (ST398-t011-SCCmecV; 107 UFC/mL). Each day we
checked the viability of MRSA both into the mucin agar carriers and in the feed medium by using MRSA-SELECT®
plates (BioRad). The results were confirmed by quantitative PCR.
Findings: MRSA population decreased as a function of time during the incubation with luminal colon microbiota
where it was not viable after 24 h. Counts of 4 log cfu/g were still obtained in the mucin agar carriers after 72 h of
incubation. On the other hand, counts of Bifidobacterium and Akkermansia increased in the mucin agar carriers as
a function of time.
Conclusion & Significance: The results support the hypothesis that a competitive microbiota may control MRSA
intestinal colonization empathize the important role of specific groups which can inhibit the adhesion of/displace
MRSA from the intestinal mucus layer.