Prevalence, antimicrobial resistance, and genotyping of Shiga toxin-producing Escherichia coli in foods of cattle origin, diarrheic cattle, and diarrheic humans in Egypt

Abstract

Shiga toxin-producing Escherichia coli (STEC) is a pathotype of E. coli that causes enteric and systemic diseases ranging from diarrhoea to severe hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). The emergence of multidrug-resistant (MDR) STEC from cattle sources has increased public health risk and limited treatment options. The prevalence of STEC was investigated in 200 raw food samples (milk and beef samples) and 200 diarrheic samples (cattle and human samples) in a matched region. The presence of stx genes (stx1 and stx2), carbapenemase-encoding genes (blaVIM, blaNDM-1, and blaIMP), and extended-spectrum β-lactamase (ESBL)-encoding genes (blaTEM group, blaCTX-M1 group, and blaOXA-1 group) was screened by polymerase chain reaction (PCR). Antibiogram and Enterobacterial repetitive intergenic consensus (ERIC)-PCR were also conducted. STEC isolates were identified in 6.5% (13/200) of food samples [6% (6/100) of milk and 7% (7/100) of beef samples] and in 11% (22/200) of diarrheic cases [12% (12/100) of cattle and 10% (10/100) of human samples]. We found that O26 (4.5%, 18/400) and O111 (1.5%, 6/400) were the most prevalent STEC serovars and were found more commonly in diarrheic samples. STEC strains with both stx genes, stx2 only, and stx1 only genotypes were present in 62.9% (22/35), 20% (7/35), and 17.1% (6/35) of isolates, respectively. Carbapenemase-producing STEC (CP STEC) isolates were found in 1.8% (7/400) of samples [0.5% (1/200) of foods and 3% (6/200) of diarrheic cases]. The blaVIM gene was detected in all CP STEC isolates, and one human isolate carried the blaNDM-1 gene. ESBL-producing STEC strains were detected in 4.3% (17/400) of samples [1.5% (3/200) of food samples and 7% (14/200) of diarrheic cases]. The blaTEM, blaCTX-M1, and blaOXA-1 genes were detected in 42.9% (15/35), 28.6% (10/35), and 2.9% (1/35) of STEC isolates, respectively. Approximately half (51.4%, 18/35) of STEC isolates were MDR STEC; all CP STEC and ESBL-producing STEC were also MDR STEC. The highest antimicrobial resistance rates were found against nalidixic acid (51.4%) and ampicillin (48.6%), whereas the lowest rates were reported against gentamicin (5.7%) and ciprofloxacin (11.4%). MDR STEC strains were 5.3 times more likely to be found in diarrheic cases than in foods (P = 0.009, 95% CI 1.5–18.7). ERIC-PCR was used for genotyping STEC isolates into 27 different ERIC-types (ETs) with a discrimination index of 0.979. Five ETs showed clusters of 2–4 identical isolates that shared the same virulence and antibiotic resistance genetic profile. Human isolates matched food isolates in two of these ET clusters (the O26 CP STEC cluster and the O111 STEC cluster), highlighting the potential cross-species zoonotic transmission of these pathogens and/or their genes in the study region. This is the first detection of CP STEC in milk and diarrheic cattle in Egypt.

Prevalence, Phylogroups, Antimicrobial Susceptibility and GE-Netic Diversity of <em>Escherichia coli</em> Isolates From Food Products

“…We also found that E. coli isolates from raw milk samples were more resistant to antibiotics than isolates from vegetable salad and ground meat samples. Obviously, resistance to different classes of antimicrobial agents among the E. coli isolates from food products have recently increased worldwide [18,28,35]. From the regional point of view, antibiotic resistance patterns of E. coli isolates from different food products at the present study are partly in agreement with previous studies in Iran [26].…”

“…In this study, 70.83% (17 out of 24) of E. coli isolates expressed resistance to at least three different classes of antibiotics and were regarded as MDR E. coli strains. The MDR rates of E. coli isolated from food samples reported in this study was significantly higher than that reported in Korea (12.5%) [25], Turkey (20%) [36], and Egypt (51.42%) [35], and lower than that reported in China (100%) [28] and Mexico (92.4%) [23]. The continuous global resistance among E. coli strains of food origins have been considered a serious threat to the public health and a major concern in food safety [16].…”

“…Moreover, Yu et al (2020) in China isolated E. coli from raw milk samples with high resistance to penicillin, acetylspiramycin, oxacillin, lincomycin, sulphamethoxazole, cephalosporin and ampicillin [28]. Recent study of Elmonir et al (2021) in Egypt also showed a high resistance to nalidixic acid, ampicillin and streptomycin in STEC strains isolated from raw milk and beef samples [35].…”

Prevalence, Phylogroups and Antimicrobial Susceptibility of Escherichia coli Isolates from Food Products

“…Moreover, Yu et al in China isolated E. coli from raw milk samples with high resistance to penicillin, acetylspiramycin, oxacillin, lincomycin, sulphamethoxazole, cephalosporin and ampicillin [ 28 ]. A recent study of Elmonir et al in Egypt also showed a high resistance to nalidixic acid, ampicillin and streptomycin in STEC strains isolated from raw milk and beef samples [ 35 ].…”

Critical occurrence of verotoxgenic <em>E.coli</em> and non-typhoidal <em>salmonella<em> in some heat treated dairy products

“…The distinguishing characteristic of STEC is the presence of one or two major forms of Shiga-like toxins encoding genes such as stx1 and stx2 (verotoxin) genes together with enterohemolysin (hly) and intimin (eaeA) virulent genes that intensify its pathogenicity in causing infections (El-Baz et al, 2017). Although the majority of sporadic cases and outbreaks of STEC/EHEC are still attributed to O157:H7 serotype, nowadays the big six serotypes (O45, O26, O103, O121, O111, and O145) of non-O157 STEC showed a marked increase in incidence rates in Egypt (Elmonir et al, 2021) and worldwide (Gould et al, 2013;Loconsole et al, 2020).…”