Prevalence and characterization of Escherichia coli O157:H7 isolates from meat and meat products sold in Amathole District, Eastern Cape Province of South Africa

Epidemiology and antimicrobial resistance profiles of pathogenic Escherichia coli from commercial swine and poultry abattoirs and farms in South Africa: A One Health approach

Pathogenic Escherichia coli (PEC) are important foodborne bacteria that can cause severe illness in humans. The PECs thrive within the intestines of humans as well as animals and may contaminate multiple ecosystems, including food and water, via faecal transmission. Abattoir and farm employees are at high risk of PEC exposure, which could translate to community risk through person-to-person contact. To determine the epidemiology and resistome of PECs in Gauteng and Limpopo provinces of South Africa, 198 swine faecal samples, 220 poultry cloacal swabs, 108 human hand swabs, 11 run-off water samples from abattoirs and farms were collected from four swine and five poultry commercial abattoirs and two swine farms. One effluent sample each was collected from four wastewater treatment plants (WWTP) and a tertiary hospital setting. Phenotypic and genotypic techniques were used including polymerase chain reaction, pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). Results showed EHEC and EPEC prevalence was 4.1 % (22/542) and 20.8 % (113/542), respectively, with the O26 serogroup detected the most in PEC isolates. According to the PFGE dendrogram, isolates from poultry, human hand swabs and run-off water clustered together. Diverse virulence factors such as the novel stx2k subtype and eae genes were detected among the 36 representative PEC isolates according to WGS. The results showed that 66.7 % (24/36) of sequenced PECs presented with multi-drug resistance (MDR) to β-lactamase 13.9 % (5/36), aminoglycoside 61.1 % (22/36), tetracycline 41.7 % (15/36) and quinolones 38.9 % (14/36). No colistin nor carbapenem resistance was detected. Sequence types (STs) associated with MDR in this study were: ST752, ST189, ST206, ST10, ST48 and ST38. The findings highlight the threat of zoonotic pathogens to close human contacts and the need for enhanced surveillance to mitigate the spread of MDR foodborne PECs.

Prevalence, antibiotic resistance, and virulence gene profile of Escherichia coli strains shared between food and other sources in Africa: A systematic review

Background and Aim

Foodborne diseases caused by Escherichia coli are prevalent globally. Treatment is challenging due to antibiotic resistance in bacteria, except for foodborne infections due to Shiga toxin-producing E. coli, for which treatment is symptomatic. Several studies have been conducted in Africa on antibiotic resistance of E. coli isolated from several sources. The prevalence and distribution of resistant pathogenic E. coli isolated from food, human, and animal sources and environmental samples and their virulence gene profiles were systematically reviewed.

Materials and Methods

Bibliographic searches were performed using four databases. Research articles published between 2000 and 2022 on antibiotic susceptibility and virulence gene profile of E. coli isolated from food and other sources were selected.

Results

In total, 64 articles were selected from 14 African countries: 45% of the studies were conducted on food, 34% on animal samples, 21% on human disease surveillance, and 13% on environmental samples. According to these studies, E. coli is resistant to ~50 antimicrobial agents, multidrug-resistant, and can transmit at least 37 types of virulence genes. Polymerase chain reaction was used to characterize E. coli and determine virulence genes.

Conclusion

A significant variation in epidemiological data was noticed within countries, authors, and sources (settings). These results can be used as an updated database for monitoring E. coli resistance in Africa. More studies using state-of-the-art equipment are needed to determine all resistance and virulence genes in pathogenic E. coli isolated in Africa.

Prevalence, characterization and antibiotic resistance of Shiga toxigenic Escherichia coli serogroups isolated from fresh beef and locally processed ready-to-eat meat products in Lagos, Nigeria

Fresh beef and meat products have been implicated in outbreaks of Shiga toxin-producing Escherichia coli (STEC) worldwide. This study investigated the prevalence of E. coli O157: H7 and non-O157 STEC serogroups in fresh beef in the open market and street vended meat products (n = 180) in Lagos metropolis, Nigeria. A combination of culture media and immunomagnetic separation followed by typing for associated virulence factors and serotypes was performed. Antimicrobial susceptibility testing was performed on the isolated STEC serotypes using the disk diffusion method. A total of 72 STEC serogroup isolates were detected from 61 out of 180 samples. The O157 STEC serotypes were detected in fresh beef, suya, minced meat and tsire with prevalence of 20.8% while non-O157 STEC serogroups were detected in all the samples. Molecular typing revealed 25% (n = 18) of the STEC serogroups showed presence of all the stx1, stx2, eaeA, fliCH7 and rfbEO157 virulence factors while 54.2% (n = 39) possessed a combination of two virulence genes. Multidrug resistance was discovered in 23.6% (n = 17) of the total STEC serogroups. Locally processed ready-to-eat meat products in Lagos metropolis, Nigeria harbour potentially pathogenic multi-drug resistant STEC serogroups that can constitute public health hazard.

Prevalence of Escherichia coli O157:H7 and associated factors in under-five children in Eastern Ethiopia

BACKGROUND

Escherichia coli O157:H7 (E. coli O157:H7) is one of the most potent zoonotic pathogens that causes mild diarrhea and leads to hemolytic uremic syndrome or death. This study was aimed to assess the prevalence and determinants of E. coli O157:H7 related to diarrhea among under-five children with acute diarrhea.

METHODS

A cross-sectional study design was carried out in 2018 on 378 under-five-year children recruited randomly from hospitals in Eastern Ethiopia. Stool specimens were collected and processed using enrichment, differential and selective medium. Among isolates, E. coli O157:H7 was confirmed using latex test (Oxoid, Basingstoke, Hants, England). Factors associated with E. coli O157:H7 infection were identified using binary and multivariable logistic regression. Associations were reported by odds ratio with 95% confidence interval.

RESULTS

The prevalence of E. coli O157:H7 related diarrhea was 15.3% (95%CI: 11.8-19.5). The E. coli O157:H7 infection was positively associated with rural residence (AOR;3.75, 95%CI:1.26-11.20), consumption of undercooked meat (AOR;3.95, 95%CI: 1.23-12.67), raw vegetables and/or fruit juice (AOR;3.37, 95%CI:1.32-8.62), presence of bloody diarrhea (AOR;4.42, 95% CI:1.78-10.94), number of under-five children in a household (AOR;7.16, 95%CI: 2.90-17.70), presence of person with diarrhea in a household (AOR;4.22, 95% CI: 1.84-12.69), owning domestic animal (AOR;3.87, 95% CI: 1.48-10.12) and uneducated mother (AOR;3.14, 95%CI: 1.05-9.42).

CONCLUSION

The Prevalence of E. coli O157:H7 related diarrhea among under-five children is relatively high in Eastern Ethiopia. The E. coli infection was associated with sanitation and hygiene in a household. Thus, education focused on food cooking and handling, child care, and household sanitation associated with animal manure in rural resident children are helpful in.

Prevalence and distribution of antimicrobial resistance determinants of Escherichia coli isolates obtained from meat in South Africa

OBJECTIVE

This study aimed to characterise antibiotics resistance of Escherichia coli isolates from the formal meat sector (FMS) and informal meat sectors (INMS).

METHOD

A total of 162 and 102 E. coli isolates from the FMS, and INMS respectively were isolated by standard culture-based, and biochemical reactions. The isolates were further confirmed by polymerase chain reaction (PCR). The disc diffusion method was used to screen for antimicrobial susceptibility against 19 different antibiotics. The presence of class 1-2 integrons in each E. coli isolates was assessed using 3'-CS and 5'-CS regions specific primers.

RESULT

Among the 19 antimicrobials, resistance to tetracyclines, aminoglycosides, cephalosporins, and nitrofurans were found to be more frequent than carbapenems and chloramphenicol. The number of multi-drug resistance ranged from three to ten antimicrobials. The resistant determinants with the highest prevalence in the FMS and INMS were; [aminoglycosides: aadA (40.6%; 31.9%), and strA (6.5%; 9.4%)], [β-lactams: ampC (20%; 45%),], [Chloramphenicol: catI (1.7%; 1.7%), and [tetracyclines: tetB (11.5%; 24%),], and [sulfonamides: sul1 (22.2%; 26.7%),].

CONCLUSION

Higher phenotypic resistance to cephalosporins and carbapenems were found in the FMS than in INMS. The multiple antibiotic resistance (MAR) indexes for FMS and INMS ranged from 0.2-0.5. The results reveal a high prevalence of multidrug-resistant E. coli isolates and resistance determinants, suggesting that consumers and handlers of such meat are at risk of contracting antibiotic-resistant E. coli-related foodborne disease.

Molecular characteristics and genotypic diversity of enterohaemorrhagic Escherichia coli O157:H7 isolates in Gauteng region, South Africa

Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 is one of the major foodborne and waterborne pathogens causing severe diseases and outbreaks worldwide. There is scarcity of EHEC O157:H7 data in South Africa. This study was carried out to determine the molecular characteristics and genotypic diversity of EHEC O157:H7 isolates in the Gauteng region, South Africa. Samples were cultured on selective chromogenic media. Antibiotic susceptibility profile of isolates was determined using the VITEK®-2 automated system. Isolates were characterised using multiplex PCR assays and the genetic diversity was determined using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). A total of 520 samples of which 270 environmental water samples and 250 stool specimens were collected and analysed. Overall, EHEC O157:H7 was recovered from 2.3% (12/520) of samples collected. Environmental water samples and clinical stool specimens showed a prevalence of 4.07% (11/270) and 0.4% (1/250) respectively. Antibiotic susceptibility profile varied from isolates with full susceptibility to isolates with resistance to multiple antibiotics. Most resistance was detected to the penicillins, specifically ampicillin (7/12), amoxicillin (3/12) and piperacillin/Tazobactam (3/12) followed by one of the folate inhibitors, trimethoprim (3/12) and the carbapenems, imipenem and meropenem (2/12) each. Three isolates harboured a combination of Shiga-toxins (Stx)-2, intimin (eae) and enterohaemolysin (hlyA) genes, while two isolates harboured the Stx-1, Stx-2 and hlyA genes. The PFGE performed showed that EHEC O157:H7 isolates were genetically diverse, with two minor pulsotypes and eight singletons. The MLST analysis identified three sequence types (STs) (ST10, ST11 and ST1204) that have been previously reported associated with outbreaks. The STs identified in this study pose a potential public health risk to consumers of untreated environmental water and closed human contacts. There is necessity to enhance surveillance in reducing the propagation of this bacterium which is a public health problem.

Cloacael Carriage and Multidrug Resistance Escherichia coli O157:H7 from Poultry Farms, Eastern Ethiopia

A cross-sectional study was carried out to determine antimicrobial drug resistance patterns of E. coli O157:H7 isolates and estimate the level of the pathogen. A total of 194 cloacae swab samples were collected randomly in two poultry farms. Standard cultural, biochemical, and serological (latex agglutination) methods were used to isolate E. coli O157:H7. The isolates were subjected to antimicrobial susceptibility testing using disc diffusion method. Out of 194 cloacae samples examined, 13.4% (n = 26) were found to be positive for E. coli O157:H7. The finding indicated differences in E. coli O157:H7 infection among the different risk factors. Chicken from Adele Poultry Farm showed higher E. coli O157:H7 infection (OR = 3.89) than Haramaya University poultry farm and young birds had more infection (OR = 4.62) than adult birds. Of the total 14 antimicrobials included in the panel of study, the susceptibility results were varied with 96.15% and 0% E. coli O157:H7 isolates expressing resistance to erythromycin, clindamycin, spectinomycin, and ciprofloxacin, respectively. Multidrug resistance to more than two antimicrobial agents was detected in 24 (92.30%) of the isolates. The study showed high presence of antimicrobial resistant isolates of E. coli O157:H7. Further study is required to better understand the ecology and evolution of bacterial resistance to antimicrobial agents.

Bacterial contamination in Saeng-go-gi, a ready-to-eat fresh raw beef dish sold in restaurants in South Korea

This study investigated the bacterial contamination levels in ready-to-eat fresh raw beef, Saeng-go-gi in Korean, sold in restaurants. A total of 462 samples were analyzed by performing an aerobic bacterial plate count, a coliform count, and an Escherichia coli O157:H7 count. Aerobic bacterial plate counts of fresh raw beef obtained from Seoul, Cheonan, Daegu, Gunsan, and Gwangju retail store restaurants were 6.46, 6.89, 6.39, 6.58, and 6.67 log CFU/g, respectively, and coliforms were 4.05, 4.97, 4.76, 3.62, and 3.32 log CFU/g, respectively. Among the 462 assessed samples, suspected E. coli O157:H7 colonies were found in 32, 24, 20, 22, and 16 samples obtained from Seoul, Cheonan, Daegu, Gunsan, and Gwangju, respectively. The identity of these isolated colonies was further assessed by using a latex agglutination kit. The agglutination assay data showed that the isolates were not E. coli O157:H7. The data from this study could be used to design better food handling practices for reducing foodborne illnesses linked to fresh raw beef consumption.

Synergistic antimicrobial activity of caprylic acid in combination with citric acid against both Escherichia coli O157:H7 and indigenous microflora in carrot juice

The identification of novel, effective, and non-thermal decontamination methods is imperative for the preservation of unpasteurized and fresh vegetable juices. The aim of this study was to examine the bactericidal effects of caprylic acid + citric acid against the virulent pathogen Escherichia coli O157:H7 and the endogenous microflora in unpasteurized fresh carrot juice. Carrot juice was treated with either caprylic acid, citric acid, or a combination of caprylic acid + citric acid at mild heating temperature (45 °C or 50 °C). The color of the treated carrot juice as well as microbial survival was examined over time. Combined treatment was more effective than individual treatment in terms of both color and microbial survival. Caprylic acid + citric acid treatment (each at 5.0 mM) at 50 °C for 5 min resulted in 7.46 and 3.07 log CFU/ml reductions in the E. coli O157:H7 and endogenous microflora populations, respectively. By contrast, there was no apparent reduction in either population following individual treatment. A validation assay using a low-density E. coli O157:H7 inoculum (3.31 log CFU/ml) showed that combined treatment with caprylic acid (5.0 mM) + citric acid (2.5 mM) at 50 °C for >5 min or with caprylic acid + citric acid (both at 5.0 mM) at either 45 °C or 50 °C for >5 min completely destroyed the bacteria. Combined treatment also increased the redness of the juice, which is a perceived indication of quality. Taken together, these results indicate that combined treatment with low concentrations of caprylic acid and citric acid, which are of biotic origin, can eliminate microorganisms from unpasteurized carrot juice.

Food safety management systems performance in African food processing companies: a review of deficiencies and possible improvement strategies

This study seeks to provide insight into current deficiencies in food safety management systems (FSMS) in African food-processing companies and to identify possible strategies for improvement so as to contribute to African countries' efforts to provide safe food to both local and international markets. This study found that most African food products had high microbiological and chemical contamination levels exceeding the set (legal) limits. Relative to industrialized countries, the study identified various deficiencies at government, sector/branch, retail and company levels which affect performance of FSMS in Africa. For instance, very few companies (except exporting and large companies) have implemented HACCP and ISO 22000:2005. Various measures were proposed to be taken at government (e.g. construction of risk-based legislative frameworks, strengthening of food safety authorities, recommend use of ISO 22000:2005, and consumers' food safety training), branch/sector (e.g. sector-specific guidelines and third-party certification), retail (develop stringent certification standards and impose product specifications) and company levels (improving hygiene, strict raw material control, production process efficacy, and enhancing monitoring systems, assurance activities and supportive administrative structures). By working on those four levels, FSMS of African food-processing companies could be better designed and tailored towards their production processes and specific needs to ensure food safety.

Detection of Escherichia coli O157:H7 using immunomagnetic separation and mPCR in Turkish foods of animal origin

The present study was conducted to investigate the presence of Escherichia coli O157:H7 in food samples of animal origin and to detect its virulence genes by immunomagnetic separation technique and multiplex PCR (mPCR). A total of 500 samples (consisting of diced meat, minced meat, burger, raw cow's milk and raw cow's milk cheese) were analysed. Escherichia coli O157:H7 was detected in 5 (1%) of 500 analysed samples including two diced meat, one minced meat and two raw-milk cheese. None of the burger samples tested contained E. coli O157:H7. Three isolates obtained from minced and diced meat were found to carry stx1 , stx2 , hlyA and eaeA genes whereas two isolates from raw-milk cheese were found to harbour the stx1 , eaeA and hlyA genes. The results of this study suggest that raw meat and raw-milk cheese tested could pose public health problems in consumers with regard to their virulence factors.

SIGNIFICANCE AND IMPACT OF THE STUDY

Escherichia coli (E. coli) O157:H7 is an important human pathogen. Escherichia coli 0157:H7 infections have been associated with consumption of uncooked meat and meat products, as well as unpasteurized dairy products. This study demonstrated that without specific tests for E. coli virulence factors raw meat and raw-milk cheese could pose public health problems to Turkish consumers.

Antimicrobial resistance of emerging foodborne pathogens: status quo and global trends

Emerging foodborne pathogens are challenging subjects of food microbiology with their antibiotic resistance and their impact on public health. Campylobacter jejuni, Salmonella spp. and Verotoxigenic Escherichia coli (VTEC) are significant emerging food pathogens, globally. The decrease in supply and increase in demand lead developed countries to produce animal products with a higher efficiency. The massive production has caused the increase of the significant foodborne diseases. The strict control of food starting from farm to fork has been held by different regulations. Official measures have been applied to combat these pathogens. In 2005 EU declared that, an EU-wide ban on the use of antibiotics as growth promoters in animal feed would be applied on 1 January 2006. The ban is the final step in the phasing out of antibiotics used for non-medical purposes. It is a part of the Commission's strategy to tackle the emergence of bacteria and other microbes resistant to antibiotics, due to their overexploitation or misuse. As the awareness raises more countries banned application of antibiotics as growth promoter, but the resistance of the emerging foodborne pathogens do not represent decrease. Currently, the main concern of food safety is counter measures against resistant bugs.

Clinical and social determinants of diarrhoeal disease in a rural HIV/AIDS clinic, South Africa: a case-control study

Diarrhoeal diseases are a common cause of morbidity and are associated with mortality in HIV-infected populations. Little is known about the contribution of clinical and socio-environmental factors to the risk of diarrhoea in these populations in rural sub-Saharan Africa. We conducted a case-control study of people attending a rural HIV clinic with an episode of diarrhoea in Bushbuckridge, South Africa. Cases were defined as HIV-positive adults with symptoms of diarrhoea before or after initiation of antiretroviral therapy (ART). Controls without diarrhoea were randomly selected from clinic attendees. Structured questionnaires and case-file reviews were undertaken to describe clinical and socioenvironmental risk factors. We recruited 103 cases of diarrhoea from 121 patients meeting case definitions. Cases were more likely to be women (P = 0.013), aged over 45 years (P = 0.002), divorced or separated (P = 0.006), have limited formal education (P = 0.003), have inadequate access to sanitation facilities (P = 0.045), have water access limited to less than three days per week (P = 0.032) and not yet initiated on ART (P < 0.001). In multivariate analysis, diarrhoea remained associated with female gender (adjusted odds ratio [aOR]: 2.02, 95% CI 1.10-3.73), older age (aOR: 6.31, 95% CI 1.50-26.50), limited access to water (aOR: 2.66, 95% CI 1.32-5.35) and pre-ART status (aOR: 5.87, 95% CI 3.05-11.27). Clinical and socio-environmental factors are associated with occurrence of diarrhoeal disease among rural HIV patients in South Africa. Further intervention research is urgently needed, combining community- and clinic-based approaches, to improve access to water, sanitation and ART for rural areas with high HIV prevalence, along with structural interventions to address gender inequities.