Short communication: Molecular characterization and antimicrobial resistance of pathogenic Escherichia coli isolated from raw milk and Minas Frescal cheeses in Brazil

Abstract

The aim of this study was to quantify, identify, evaluate antimicrobial resistance, and characterize the virulence factors of enteropathogenic (EPEC), Shigatoxigenic (STEC), and enterohemorrhagic (EHEC) Escherichia coli in raw milk (RM) and legal (LMFC) and illegal (IMFC) Minas Frescal cheeses in southern and northeast Brazil. Illegal cheeses are those made without official inspection service or sanitary surveillance. We evaluated samples of RM produced in Paraná (southern) and Maranhão (northeast) States, LMFC produced using pasteurized milk in inspected industries, and IMFC potentially produced with raw milk. Mean total coliform counts were 8.4 × 10 4 cfu/mL for RM, 1.4 × 10 7 cfu/mL for LMFC, and 2.9 × 10 7 cfu/ mL for IMFC. Mean E. coli counts were 2.4 × 10 3 cfu/ mL for RM, 1.9 × 10 2 cfu/mL for LMFC, and 1.1 × 10 5 cfu/mL for IMFC. Among the 205 E. coli isolates from RM, 9.75% were identified as EPEC, mainly (90%) in samples from Paraná. Of the total isolates from the cheese samples, 97.4% (n = 111) came from IMFC, of which 1.8 and 2.7% were identified as EPEC and STEC, respectively; no EHEC was detected. The phylogenetic group A (60%) and typical EPEC (68%) predominated, which confirms the possible human origin of pathogenic isolates in RM and IMFC. Of these, 50% were resistant to at least one antibiotic, and streptomycin was the antimicrobial with the highest number (8) of EPEC and STEC resistant isolates. This study reports the first isolation of serogroup O28ac in Brazilian milk. We found no predominance of a specific serogroup of EPEC or STEC in milk or cheese or clonal isolates in the same sample, indicating different origins of the contamination in these products, presumably mostly related to poor hygienic handling.

Occurrence, Pathogenic Potential and Antimicrobial Resistance of Escherichia coli Isolated from Raw Milk Cheese Commercialized in Banat Region, Romania

“…The overall 81.1% isolation frequency rate that was recorded suggested that most of these assortments were produced in improper hygiene and sanitary conditions. This contamination rate is higher than previously reported rates for raw milk telemea cheese (another white brined traditional product) in Romania (62.5%; [ 9 ]), or for white cheese in Turkey (60%; [ 16 ]), but lower than rates found in Minas Frescal (100%; [ 17 ]), and soft cheese assortments (97.7%; [ 18 ]) in Brazil. Furthermore, the study showed that 68.9% of positive samples had an E. coli contamination level below 10 CFU/g.…”

Molecular characteristics of Escherichia coli from bulk tank milk in Korea

“…The phylogenetic characterization of E. coli is an important tool to improve the understanding of the relationship between strains and disease [ 16 ]. E. coli is commonly classified into four major phylogenetic groups A, B1, B2, and D [ 8 17 18 ]. Group D was the most prevalent (59.6%), followed by B1 (25.1%).…”

Evaluation of Virulence Factors, Antibiotic Resistance, and Biofilm Formation of Escherichia coli Isolated from Milk and Dairy Products in Isfahan, Iran

“…The control strains included E. coli O157:H7 ATCC43895 and E. coli ATCC25922 (non-pathogenic). Furthermore, positive PCR samples for specific primers were confirmed using a single PCR assay [ 31 , 32 ].…”