Shiga-Toxin Producing Escherichia Coli in Brazil: A Systematic Review

Impact of the Probiotic Organism Megasphaera elsdenii on Escherichia coli O157:H7 Prevalence in Finishing Cattle

Feedlot cattle commonly shed the foodborne pathogen Escherichia coli O157:H7 in their feces. Megasphaera elsdenii (ME), a lactic acid-utilizing bacterium, is commonly administered to cattle to avoid lactate accumulation in the rumen and to control ruminal acidosis. The impact of administering ME on foodborne pathogen prevalence, specifically E. coli O157:H7, has not been explored. The purpose of this study was to quantify E. coli O157:H7 prevalence in finishing cattle administered ME. Cattle (n = 448) were assigned to treatments in a randomized complete block design with repeated measurements over two sampling periods. Treatments were arranged as a 2 × 2 factorial containing: ruminally protected lysine (RPL; included for a complementary study) fed at 0% or 0.45% of diet dry matter; with or without ME. Freeze-dried ME was administered as an oral drench (1 × 1010 CFU/steer on day one) and then top dressed onto basal diets (1 × 107 CFU/steer) daily thereafter. Rectoanal mucosal swabs (RAMS) were obtained from animals before harvest to determine the E. coli O157:H7 prevalence. The inclusion of RPL (P = 0.2136) and ME (P = 0.5012) did not impact E. coli O157:H7 prevalence, and RPL was not included in any significant interactions (P > 0.05). A significant interaction was observed between ME and sampling period (P = 0.0323), indicating that the effect of ME on E. coli O157:H7 prevalence varied over the sampling period. A diet containing ME reduced the odds of E. coli O157:H7 prevalence by 50% during sampling period 1 (8.0% and 14.7% for cattle with and without ME, respectively) and increased the odds by 23% during sampling period 2 (10.8% and 8.9% for cattle with and without ME, respectively). Administering ME in cattle diets did not impact E. coli O157:H7 in feedlot cattle. This is the first study to investigate the use of ME as a preharvest food safety intervention in cattle, and additional research is necessary to determine the efficacy.

Absence of Shiga toxin-producing Escherichia coli (STEC) in organic leafy greens from the metropolitan region of São Paulo, Brazil

Shiga toxin-producing Escherichia coli (STEC) is an important pathogen with public health implications, including its potential association with vegetables. In this study, we investigated the presence of STEC in vegetables obtained from organic producers located in São Paulo city, Brazil. As part of a routine surveillance study conducted over (years of isolation), a total of 200 samples of organic vegetables were screened using biochemical and PCR methods. Among the vegetable samples tested, 30 (15%) were positive for non-Shiga toxin-producing E. coli. While no STEC was detected in the organic vegetables in this study, the presence of non-STEC in vegetables raises concerns about the lack of proper hygiene practices during vegetable handling. This contamination represents a public health risk, particularly considering that these isolates can still be pathogenic, and vegetables are often consumed raw. To address this important issue, continuous monitoring of these farms is recommended to ensure the quality and safety of organic vegetables produced for both domestic consumption and exportation.

Escherichia coli O157:H7 strains in bovine carcasses and the impact on the animal production chain

Foodborne diseases are characterized by conditions that can induce symptomatic illnesses in their carriers, and therefore represent a serious problem. They are important conditions from a clinical and epidemiological point of view, and are associated with the occurrence of serious public health problems, with a strong impact on morbidity and mortality. The Escherichia coli (E. coli) is an enterobacterium associated with enteric conditions of variable intensity and which are accompanied by blood. The transmission routes are mainly based on the consumption of contaminated food and water sources. Shiga toxin-producing E. coli (STEC) are considered a serogroup of E. coli, are capable of producing Shiga-type toxins (Stx 1 and Stx 2) and the O157:H7 strain is one of the best-known serotypes. The early detection of this pathogen is very important, especially due to the capacity of contamination of carcasses destined for food consumption and supply of productive markets. Sanitary protocols must be developed and constantly reviewed in order to prevent/control the presence of the pathogen.

Association of resistance to quaternary ammonium compounds and organic acids with genetic markers and their relationship to Escherichia coli serogroup

Sanitizer resistance is being extensively investigated due to the potential for bacterial survival and cross-resistance with other antimicrobials. Similarly, organic acids are being used due to their microbial inactivation potential as well as being generally recognized as safe (GRAS). However, little is known about associations of genetic and phenotypic factors in Escherichia coli related to resistance to sanitizers and organic acids as well as differences between "Top 7" serogroups. Therefore, we investigated 746 E. coli isolates for resistance to lactic acid and two commercial sanitizers based on quaternary ammonium and peracetic acid. Furthermore, we correlated resistance to several genetic markers and investigated 44 isolates using Whole Genome Sequencing. Results indicate that factors related to motility, biofilm formation, and Locus of Heat Resistance played a role in resistance to sanitizers and lactic acid. In addition, Top 7 serogroups significantly differed in sanitizer and acid resistance, with O157 being the most consistently resistant to all treatments. Finally, mutations in rpoA, rpoC, and rpoS genes were observed, in addition to presence of a Gad gene with alpha-toxin formation in all O121 and O145 isolates, which may be related to increased resistance of these serogroups to the acids used in the present study.

Antimicrobial resistance and molecular characterization of Escherichia coli isolated from bovine mastitis samples in Nghe An province, Vietnam

Background and Aim

Vietnam's dairy sector is in its early phase of large-scale farming development. Therefore, mastitis in cows is always a concern to farm owners. This study aimed to determine the antimicrobial susceptibility, resistance, and virulence-related genes of Escherichia coli isolated from bovine mastitis in Nghe An province of Vietnam.

Materials and Methods

Fifty E. coli strains were isolated from the clinical cases and subjected to this study. All isolates were tested for antimicrobial susceptibility by the disk-diffusion method, as described by the Clinical and Laboratory Standards Institute. Antimicrobial and virulence genes were confirmed by polymerase chain reaction with specific primers.

Results

All isolates were resistant to lincomycin and sulfamethoxazole and sensitive to gentamicin, while other antimicrobials showed resistance from 2% to 90%. Multidrug resistance was confirmed in 46% of isolates, and none of them were identified as extended-spectrum beta-lactamase producers. From fifty strains tested for antimicrobial and virulence genes, six isolates harbored tetA, 6 tetB, 13 sul1, 15 sul2, 2 Intimin (eae), 1 iutA, and 3 stx2.

Conclusion

Antimicrobial and multidrug resistances are the main virulence factors of E. coli isolated from bovine mastitis in Vietnam. The virulence genes encoding adhesion, siderophore, Shiga-toxin-producing, and antimicrobials resistant were first reported in Vietnam with low prevalence and contributed to the pathogenesis.

Simultaneous Detection of Five Foodborne Pathogens Using a Mini Automatic Nucleic Acid Extractor Combined with Recombinase Polymerase Amplification and Lateral Flow Immunoassay

In recent years, foodborne disease outbreaks have caused huge losses to the economy and have had severe impacts on public health. The accuracy and variety of detection techniques is crucial to controlling the outbreak and spread of foodborne diseases. The need for instruments increases the difficulty of field detection, while manually-handled samples are subject to user error and subjective interpretation. Here, we use a mini automatic nucleic acid extractor combined with recombinant polymerase amplification (RPA) and lateral flow immunoassay (LFIA) for simultaneous quantitative detection of five major foodborne pathogens. The pre-treatment device using the magnetic bead method allows for nucleic acid extraction of the reagent tank without manual operation, which is highly efficient and stable for preventing aerosol contamination. The nuc gene of Staphylococcus aureus, the toxR gene of Vibrio parahaemolyticus, the rfbE gene of Escherichia coli O157:H7, the hlyA gene of Listeria monocytogenes, and the fimY gene of Salmonella enterica were used as target fragments. The labeled antibody concentration is optimized on the LFIA to find the equilibrium point for the binding capacity of the five chemical markers and to efficiently and accurately visualize the bands. The RPA assay shows an optimal performance at 37 °C for 15 min. The optimized RPA-LFIA detection limit can reach 10¹ CFU/mL. There was no cross-reactivity among forty-eight strains. Furthermore, the average recoveries in spiked food samples were 90.5–104.5%. In summary, the RPA-LFIA established in this study can detect five pathogenic bacteria simultaneously with little dependence on laboratory equipment, and it has promising prospects for screening in low-resource areas.

Escherichia coli and Pseudomonas aeruginosa Isolated From Urine of Healthy Bovine Have Potential as Emerging Human and Bovine Pathogens

The study of livestock microbiota has immediate benefits for animal health as well as mitigating food contamination and emerging pathogens. While prior research has indicated the gastrointestinal tract of cattle as the source for many zoonoses, including Shiga-toxin producing Escherichia coli and antibiotic resistant bacteria, the bovine urinary tract microbiota has yet to be thoroughly investigated. Here, we describe 5 E. coli and 4 Pseudomonas aeruginosa strains isolated from urine of dairy Gyr cattle. While both species are typically associated with urinary tract infections and mastitis, all of the animals sampled were healthy. The bovine urinary strains were compared to E. coli and P. aeruginosa isolates from other bovine samples as well as human urinary samples. While the bovine urinary E. coli isolates had genomic similarity to isolates from the gastrointestinal tract of cattle and other agricultural animals, the bovine urinary P. aeruginosa strains were most similar to human isolates suggesting niche adaptation rather than host adaptation. Examination of prophages harbored by these bovine isolates revealed similarity with prophages within distantly related E. coli and P. aeruginosa isolates from the human urinary tract. This suggests that related urinary phages may persist and/or be shared between mammals. Future studies of the bovine urinary microbiota are needed to ascertain if E. coli and P. aeruginosa are resident members of this niche and/or possible sources for emerging pathogens in humans.

Occurrence of the Seven Most Common Serotypes of Shiga Toxin-Producing Escherichia coli in Beef Cuts Produced in Meat Processing Plants in the State of São Paulo, Brazil

ABSTRACT

Healthy cattle are considered the main reservoir of Shiga toxin-producing Escherichia coli (STEC) strains, so in some places in the world, products derived from beef are the most common source for disease outbreaks caused by these bacteria. Therefore, to guarantee that the beef produced by our slaughterhouses is safe, there is a need for continuous monitoring of these bacteria. In this study, 215 beef cuts were evaluated, including chilled vacuum-packed striploins (151 samples), rib eyes (30 samples), and knuckles (34 samples), from March to June 2018. These meat samples were collected from the slaughter of unconfined cattle, being arbitrarily collected from eight meat processing companies in São Paulo state, Brazil. Each sample was examined for the presence of STEC toxin type (stx1 and/or stx2 genes) and also the attaching and effacing E. coli (eae) gene, determined by a multiplex PCR assay. We show that the major seven STEC strains (O serogroups O26, O45, O103, O111, O121, O145, and O157) are not detected in any of the analyzed beef cut samples; however, three of them presented the virulence eae gene. Therefore, the absence of STEC strains in the beef samples may be an indication of the low prevalence of this pathogen in the cattle herd on the farm, associated with good hygiene and handling practices adopted by the meat industry.

HIGHLIGHTS

A Systematic Review on Nanoencapsulation Natural Antimicrobials in Foods: In Vitro versus In Situ Evaluation, Mechanisms of Action and Implications on Physical-Chemical Quality

Natural antimicrobials (NA) have stood out in the last decade due to the growing demand for reducing chemical preservatives in food. Once solubility, stability, and changes in sensory attributes could limit their applications in foods, several studies were published suggesting micro-/nanoencapsulation to overcome such challenges. Thus, for our systematic review the Science Direct, Web of Science, Scopus, and Pub Med databases were chosen to recover papers published from 2010 to 2020. After reviewing all titles/abstracts and keywords for the full-text papers, key data were extracted and synthesized. The systematic review proposed to compare the antimicrobial efficacy between nanoencapsulated NA (nNA) and its free form in vitro and in situ studies, since although in vitro studies are often used in studies, they present characteristics and properties that are different from those found in foods; providing a comprehensive understanding of primary mechanisms of action of the nNA in foods; and analyzing the effects on quality parameters of foods. Essential oils and nanoemulsions (10.9–100 nm) have received significant attention and showed higher antimicrobial efficacy without sensory impairments compared to free NA. Regarding nNA mechanisms: (i) nanoencapsulation provides a slow-prolonged release to promote antimicrobial action over time, and (ii) prevents interactions with food constituents that in turn impair antimicrobial action. Besides in vitro antifungal and antibacterial, nNA also demonstrated antioxidant activity—potential to shelf life extension in food. However, of the studies involving nanoencapsulated natural antimicrobials used in this review, little attention was placed on proximate composition, sensory, and rheological evaluation. We encourage further in situ studies once data differ from in vitro assay, suggesting food matrix greatly influences NA mechanisms.

Shiga toxin-producing Escherichia coli isolated from pasteurized dairy products from Bahia, Brazil

The presence of pathogenic Shiga toxin-producing Escherichia coli (STEC) in dairy products represents a public health concern because of its ability to produce the toxins Stx1 and Stx2, which cause intestinal diseases. Monitoring the stages of milk production and checking dairy products for contamination are crucial steps to ensure dairy safety. This study aimed to report the occurrence of thermotolerant coliforms, E. coli, and STEC strains in pasteurized dairy products and to evaluate the antibiotic resistance profiles, serotypes, and characterizations of the STEC isolates by pulsed-field gel electrophoresis. We obtained a total of 138 pasteurized dairy products from 15 processing plants in Bahia, Brazil, to examine coliforms, E. coli, and STEC strains. We found that 43% of samples (59/138) contained thermotolerant coliforms, and 30% (42/138) did not comply with Brazilian regulations. Overall, 6% (9/138) were positive for E. coli and 4% (5/138) were positive for STEC. We recovered 9 STEC isolates from pasteurized cream (2/9), Minas Padrão cheese (2/9), Minas Frescal cheese (4/9), and ricotta (1/9). All isolates were stx2-positive, and 2 were eae-positive. All isolates were negative for the "big 6" STEC serogroups, belonging instead to serotypes ONT:HNT, ONT:H12, O148:H-, OR:H40, OR:HNT, and O148:HNT. Pulsed-field gel electrophoresis revealed 100% genetic similarity among 3 isolates from 2 different samples produced in the same production facility, which may suggest cross-contamination. As well, we found isolates that were 98% similar but in samples produced in different production facilities, suggesting a mutual source of contamination or a circulating strain. Two STEC strains exhibited resistance to streptomycin. Although the isolates presented a low resistance profile and no strain belonged to the "big 6" pathogenic group, the circulation of stx2-positive STEC strains in ready-to-eat products highlights the importance of epidemiological surveillance inside the Brazilian dairy chain.

Shiga toxin-producing Escherichia coli (STEC) in bovine meat and meat products over the last 15 years in Brazil: A systematic review and meta-analysis

We conducted a systematic review and meta-analysis to determine the rate of contamination in bovine meat and meat products with Shiga toxin-producing Escherichia coli (STEC) in Brazil over the last fifteen years. Data were obtained from online databases in February 2020, and 25 papers were selected from 1036 articles identified in the literature search and 13 articles from gray literature, totaling 4286 samples analyzed. The overall rate of STEC was estimated to be 1% in Brazil. The highest rate (9%) was observed in Mato Grosso, followed by Rio Grande do Sul (1%), Goiás (1%), and São Paulo (1%). Regarding the sample type analyzed, hot carcasses had the highest rate (8%) of positive samples for STEC, followed by cold carcasses (2%) and beef samples (1%). As the available data were concentrated in the São Paulo state, the findings of this meta-analysis reveal the need for further studies in Brazil to allow better risk assessment and prevention of human STEC infections.

Prevalence and antibiotic resistance profile of Shiga toxin-producing Escherichia coli isolated from diarrheal samples

Background and Objectives:

Enterohemorrhagic Escherichia coli (EHEC) causes bloody and non-bloody diarrhea, intestinal infection and extraintestinal complications in humans. This study aimed to isolate and evaluate the prevalence of E. coli O157: H7 and other Shiga toxin-producing E. coli (STEC) and identify the virulence genes (stx1, stx2, hly and eaeA) from patients with diarrhea. Also, the antibiotic resistance profile of the isolated strains was evaluated.

Materials and Methods:

A total of 100 stool samples were collected from patients with acute diarrhea referring to the hospital and clinics in Isfahan County, Iran. Phenotypic tests and PCR assay were used for detection of E. coli O157: H7 and other Shiga toxin-producing E. coli. The presence of virulence genes (stx1, stx2, hly and eaeA) were identified by PCR. The antibiotic resistance profile of the isolates was determined using the agar disk diffusion method. The results were analyzed descriptively by Sigma stat version 4 software.

Results:

Seventy - eight out of 100 samples (78%) were contaminated with E. coli. E. coli O157 was isolated from five samples (6.4%), of which only two strains (2.56%) were identified as E. coli O157: H7. According to the results, out of two E. coli O157: H7 isolates, one (50%) isolate contained eaeA and two isolates (100%) contained Stx1, Stx2, hlyA genes. Out of three (3.84%) E. coli O157: HN, one of the isolate (33.3%) contained stx1 and, two isolates (66.7%) were positive for hlyA genes. Also, the results revealed that six strains (7.69%) were non-O157: H7 STEC, of which two isolates (33.3%) contained stx1 and four isolates (66.7%) were positive for stx2 and hlyA genes. The results of antibiogram tests revealed that all of the STEC isolates (100%) were sensitive to imipenem followed by kanamycin, gentamicin and nitrofurantoin (91%). High resistance (54.5%) to ampicillin and ciprofloxacin was observed among the STEC isolates.

Conclusion:

The results of the current study showed that although the prevalence of E. coli O157: H7 was low among patients with diarrhea, the other STEC strains with relative resistance to antibiotics are more prevalent.

Biofilm formation by South African non-O157 Shiga toxigenic Escherichia coli on stainless steel coupons

This study examined the biofilm-forming ability of six non-O157 Shiga-toxin-producing Escherichia coli (STEC) strains: O116:H21, wzx-Onovel5:H19, O129:H21, O129:H23, O26:H11, and O154:H10 on stainless steel coupons after 24, 48, and 72 h of incubation at 22 °C and after 168 h at 10 °C. The results of crystal violet staining revealed that strains O129:H23 and O154:H10 were able to form biofilms on both the submerged surface and the air-liquid interface of coupons, whereas strains O116:H21, wzx-Onovel5:H19, O129:H21, and O26:H11 formed biofilm only at the air-liquid interface. Viable cell counts and scanning electron microscopy showed that biofilm formation increased (p < 0.05) over time. The biofilm-forming ability of non-O157 STEC was strongest (p < 0.05) at 22 °C after 48 h of incubation. The strongest biofilm former regardless of temperature was O129:H23. Generally, at 10 °C, weak to no biofilm was observed for isolates O154:H10, O116:H21, wzx-Onovel5:H19, O26:H11, and O129:H21 after 168 h. This study found that temperature affected the biofilm-forming ability of non-O157 STEC strains. Overall, our data indicate a high potential for biofilm formation by the isolates at 22 °C, suggesting that non-O157 STEC strains could colonize stainless steel within food-processing facilities. This could serve as a potential source of adulteration and promote the dissemination of these potential pathogens in food.

Typical and Atypical Hemolytic Uremic Syndrome in the Critically Ill

Hemolytic uremic syndrome is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Disseminated intravascular coagulation, thrombotic thrombocytopenic purpura, and hemolytic uremic syndrome have a similar clinical presentation. Diagnostic needs to be prompt to decrease mortality, because identifying the different disorders can help to tailor specific, effective therapies. However, diagnosis is challenging and morbidity and mortality remain high, especially in the critically ill population. Development of clinical prediction scores and rapid diagnostic tests for hemolytic uremic syndrome based on mechanistic knowledge are needed to facilitate early diagnosis and assign timely specific treatments to patients with hemolytic uremic syndrome variants.

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Complete genome sequence of the novel phage vB_EcoS_PHB17, which infects Shiga-toxin-producing Escherichia coli

The complete genome of the novel phage vB_EcoS_PHB17, which infects Shiga-toxin-producing Escherichia coli, was sequenced, revealing a linear double-stranded DNA genome of 48,939 bp with 46% GC content and protruding 150-bp 5' cohesive termini. The genome contained 85 open reading frames, 28 of which were annotated with known functions. No tRNA-encoding genes were detected. Phylogenetic analysis suggested that phage PHB17 is a novel phage of family Siphoviridae.