Oana Reget

Concerning Increase in Antimicrobial Resistance in Shiga Toxin-Producing Escherichia coli Isolated from Young Animals during 1980–2016

This study was conducted in order to assess the antimicrobial resistance patterns of E. coli isolated from young animals affected between 1980 and 2016. The selected isolates for this study (n=175) carried stx1/stx2 genes and the most prevalent type of pathogenic E. coli found belonged to serogroup O101, antigen (K99)–F41 positive. All STEC-positive isolates were tested for susceptibility to 11 antimicrobials. Multidrug resistance (MDR) increased from 11% during the 1980s to 40% between 2000 and 2016. Resistance to tetracycline and streptomycin was the most frequent co-resistance phenotype (37%). Co-resistance to tetracycline and sulfonamide was found in 21% of E. coli isolates, while the MDR pattern to tetracycline, sulfonamide, and streptomycin was observed in 12% of the strains tested. Only 8% of isolates were co-resistant to tetracycline, ampicillin, streptomycin, and sulfonamide. The most common resistance genes found were those encoding for tetracycline, sulphonamides, and streptomycin, with 54% (n=95) of the tested isolates containing at least one of the genes encoding tetracycline resistance. A total of 87% of E. coli that tested positive for tetracycline (tetA, tetB, and tetC) and sulphonamide (sul1) resistance genes were isolated between 2000 and 2016. A large number of isolates (n=21) carried int1 and a nucleotide sequence analysis revealed that all class 1 integron gene cassettes carried sul1, tet, and dfrA1 resistance genes. An increase was observed in the level of resistance to antimicrobials in Romania, highlighting the urgent need for a surveillance and prevention system for antimicrobial resistance in livestock in Eastern Europe.

Microbiological Assessment of Raw Meat Used in Fast-Food Products Sold for Public Consumption

Raw meat contains sufficient nutrients to support microbial growth and because of that the proper surveillance of the meat products destined for public consumption is mandatory. The purpose of this study was to conduct a microbiological risk assessment regarding the safety of pork, chicken and beef meat products found in fast –food units from Transylvania area. One hundred and seventy samples of raw meat(n=35) and fried foods made of pork(n=39), chicken(n=45)and beef products(n=51) were purchased randomly from 5 different fast-food units located in the study area.The determination performed in order to assess the safety was the total number of Enterobacteriaceae, evaluation of toxigenic E. coli and Salmonella spp. presence, which is also the parameter requested by the current regulation. The levels of contamination with Enterobacteriaceae that exceeded the current legislation limit were 6/39 (15%), 6/45 (13%) and 5/51 (9%) in cooked pork, chicken and respectively beef meat. Given the similar rate of contaminations among these three categories of food there were no statistical differences noticed (p>0.05). Results showed that in 35 of 170 (20%) collected food samples were found total Enterobacteriaceae count over 3 log CFU/g and 12 of 170 (7%) were found with coliform bacteria. Raw meat destined for fast-food industry can represent a risk for public health if hygiene and refrigerating conditions are not properly monitored.

First study on characterization of virulence and antibiotic resistance genes in verotoxigenic and enterotoxigenic E. coli isolated from raw milk and unpasteurized traditional cheeses in Romania

The study focused on the incidence of enterotoxigenic Escherichia coli (ETEC) and verotoxigenic E. coli (VTEC) in raw milk and traditional dairy cheeses marketed in Romania, characterizing the virulence and antibiotic resistance genes of these isolates. One hundred and twenty samples of raw milk and 80 samples of unpasteurized telemy cheese were collected and cultured according to the international standard protocol. All the characteristic E. coli cultures were analyzed for the presence of STa, STb, LT, stx1, and stx2 toxicity genes. The ETEC/VTEC strains were tested for the presence of antibiotic resistance genes, such as aadA1, tetA, tetB, tetC, tetG, dfrA1, qnrA, aaC, sul1, blaSHV, blaCMY, blaTEM, and ere(A), using PCR. The results showed that 27 samples (18.62%) were positive for one of the virulence genes investigated. 48.1% (nxa0=xa013) tested positive at the genes encoding for tetracycline resistance, tetA being the most prevalent one (61.5%; nxa0=xa08). A high percent (33.3%; nxa0=xa09) revealed the beta-lactamase (blaTEM) resistance gene, and none of the samples tested positive for blaCMY and blaSHV genes. The genes responsible for resistance to sulfonamides (sul1) and trimethoprim (dfrA1) were detected in rates of 14.8% (nxa0=xa04) and 7.4% (nxa0=xa02), respectively. E. coli is highly prevalent in raw milk and unpasteurized cheeses marketed in Romania. These strains might represent an important reservoir of resistance genes which can easily spread into other European countries, given the unique market.