Journal of Microbial & Biochemical Technology

Molecular typing of methicillin resistant Staphylococcus aureus (MRSA) isolated from milk and dairy products in southern Italy

Joint Event on 4^th World Congress and Expo on Applied Microbiology & 2^nd International Conference on Food Microbiology

November 29-December 01, 2017 Madrid, Spain

Giovanna La Salandra, Maria Grazia Basanisi, Gianfranco La Bella and Gaia Nobili

Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, Italy

Posters & Accepted Abstracts: J Microb Biochem Technol

Abstract:

Methicillin resistant Staphylococcus aureus (MRSA) is a significant and costly public health concern because it may enter the human food chain and contaminate milk and dairy products causing foodborne illness. The purpose of this study was to determine the occurrence and the characteristics (SCCmec-, spa-, multi locus sequence typing) of MRSA isolated from dairy food, with respect to the genes encoding Panton Valentine leukocidin (PVL) and ability to form biofilm. Nine (7.5%) MRSA strains were isolated from 120 samples of milk and dairy products produced in Apulia region (south Italy) from January to June 2017. Three different spa-types and STs were identified: the most frequently recovered spa-type and ST was t355-ST152 (55.6%), followed by t899-ST398 (22.2%) and t127-ST1 (22.2%). All isolates harbored the SCCmec type V (66.7%) or IVa (22.3%) and in one isolate (11.1%), ST398/t899, the SCCmec resulted was not detected. MRSA isolates with genotype t355/ ST152/SCCmec type V were PVL-positive, whereas t899/ST398/SCCmec type V and t127/ST1/SCCmec type IVa MRSA isolates were PVL-negative. All MRSA isolates were low grade biofilm positive using a semi-quantitative adherence assay by microtiter plate (MTP). The most common MRSA strain (t355-ST152) is a CA-MRSA clone associated to human infections, and reported in many countries, including Italy. MRSA ST 398 (t899) is considered an important livestock-associated lineage associated to several cases of infections of variable clinical relevance. MRSA t127-ST1 can cause bovine mastitis and is associated with pig carriage in Italy and other European countries. The detection of MRSA in food of animal origin is a potential health hazard related to some factors such as the number of colonizer/infected food handlers, the level of hygiene in food plants and transport systems, and the level of raw milk contamination; thus it is necessary monitoring food-producing animals and improving hygiene in food practices in order to reduce the microbiological risk to minimum. Recent Publications 1. Alba P, Feltrin F, Cordaro G, Porrero M C, Kraushaar B, Argudín M A, Nykasenoja S, Monaco M, Stegger M, Aarestrup F M, Butaye P, Franco A and Battisti A (2015) Livestock-associated methicillin resistant and methicillin susceptible Staphylococcus aureus sequence type (CC)1 in European farmed animals: high genetic relatedness of isolates from Italian cattle herds and humans. PLoS One 10:e0137143. 2. Basanisi M G, La Bella G, Nobili G, Franconieri I and La Salandra G (2017) Genotyping of methicillin-resistant Staphylococcus aureus (MRSA) isolated from milk and dairy products in south Italy. Food Microbiol. 62:141-146. 3. Mancini F, Monaco M, Basanisi M G, La Salandra G and Pantosti A (2015) An unusual PVL-positive MRSA strain in milk and dairy products from a region of south Italy. J. Glob. Antimicrob. Resist 3:151-152. 4. Petinaki E and Spiliopoulou L (2012) Methicillin-resistant Staphylococcus aureus among companion and food-chain animals: Impact of human contacts. Clin. Microbiol. Infect. 18:626-634. 5. Zmantar T, Kouidhi B, Miladi H, Mahdouani K and Bakhrouf A (2010) A microtiter plate assay for Staphylococcus aureus biofilm quantification at various pH levels and hydrogen peroxide supplementation. New Microbiol. 33:137145.

Biography :

Giovanna La Salandra, Head of Scientific Research and Development of IZS PB, has her expertise in molecular microbiology applied in the field of food safety. She is Manager of many scientific projects in the field of food safety, funded by Italian Ministry of Health. She has published many papers in peer reviewed scientific journals as author and co-author. She has participated in national and international congress/conferences focused on food safety and hygiene food control.