Genetic Relatedness Among Escherichia coli Pathotypes Isolated from Food Products for Human Consumption in Cartagena, Colombia

Detecting Class 1 Integrons and Their Variable Regions in Escherichia coli Whole-Genome Sequences Reported from Andean Community Countries

Various genetic elements, including integrons, are known to contribute to the development of antimicrobial resistance. Class 1 integrons have been identified in E. coli isolates and are associated with multidrug resistance in countries of the Andean Community. However, detailed information on the gene cassettes located on the variable regions of integrons is lacking. Here, we investigated the presence and diversity of class 1 integrons, using an in silico approach, in 2533 whole-genome sequences obtained from EnteroBase. IntFinder v1.0 revealed that almost one-third of isolates contained these platforms. Integron-bearing isolates were associated with environmental, food, human, and animal origins reported from all countries under scrutiny. Moreover, they were identified in clones known for their pathogenicity or multidrug resistance. Integrons carried cassettes associated with aminoglycoside (aadA), trimethoprim (dfrA), cephalosporin (blaOXA; blaDHA), and fluoroquinolone (aac(6')-Ib-cr; qnrB) resistance. These platforms showed higher diversity and larger numbers than previously reported. Moreover, integrons carrying more than three cassettes in their variable regions were determined. Monitoring the prevalence and diversity of genetic elements is necessary for recognizing emergent patterns of resistance in pathogenic bacteria, especially in countries where various factors are recognized to favor the selection of resistant microorganisms.

Loads of Coliforms and Fecal Coliforms and Characterization of Thermotolerant Escherichia coli in Fresh Raw Milk Cheese

The aim of this study was to assess the hygienic status of raw milk cheese and determine the trends of virulence and antimicrobial resistance in thermotolerant Escherichia coli. Two hundred samples of karish, a popular Egyptian fresh raw milk cheese, were analyzed for coliforms and fecal coliforms using a standard most probable number (MPN) technique. Overall, 85% of samples were unsuitable for consumption, as they exceeded Egyptian standards for coliforms (10 MPN/g), and 65% of samples exhibited coliforms at 44.5 °C. Of 150 recovered thermotolerant strains, 140 (93.3%) were identified as E. coli. Importantly, one Shiga toxin-producing E. coli (STEC) strain carrying a striking virulence pattern, stx1−, stx2+, eae−, was detected. Eleven strains (7.8%, 11/140) showed resistance to third-generation cephalosporins. Antibiotic resistance genes included bla_SHV, bla_CTX-M, qnrS, tet(A), and tet(B), which were present in 4.3%, 2.8%, 0.71%, 2.1%, and 0.71% of isolates, respectively. In conclusion, this study indicated that hygienic-sanitary failures occurred throughout the production process of most retail karish cheese. Furthermore, our findings emphasize the need for adopting third-generation cephalosporin-resistant E. coli as an indicator for monitoring antimicrobial resistance in raw milk cheese to identify the potential public health burden associated with its consumption.

Prevalence, Antimicrobial Resistance, and Whole Genome Sequencing Analysis of Shiga Toxin-Producing Escherichia coli (STEC) and Enteropathogenic Escherichia coli (EPEC) from Imported Foods in China during 2015–2021

Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic Escherichia coli (EPEC) are foodborne pathogens that cause hemolytic uremic syndrome and fatal infant diarrhea, respectively, but the characterization of these bacteria from imported food in China are unknown. A total of 1577 food samples from various countries during 2015–2021 were screened for STEC and EPEC, and the obtained isolates were tested for antimicrobial resistance and whole genome sequencing analysis was performed. The prevalence of STEC and EPEC was 1.01% (16/1577) and 0.51% (8/1577), respectively. Antimicrobial resistances to tetracycline (8%), chloramphenicol (8%), ampicillin (4%), ceftazidime (4%), cefotaxime (4%), and trimethoprim-sulfamethoxazole (4%) were observed. The antimicrobial resistance phenotypes corresponded with genotypes for most strains, and some resistance genes were related to mobile genetic elements. All 16 STEC isolates were eae negative, two solely contained stx1 (stx1a or stx1c), 12 merely carried stx2 (stx2a, stx2d, or stx2e), and two had both stx1 and stx2 (stx1c + stx2b, stx1a + stx2a + stx2c). Although they were eae negative, several STEC isolates carried other adherence factors, such as iha (5/16), sab (1/16), and lpfA (8/16), and belonged to serotypes (O130:H11, O8:H19, and O100:H30) or STs (ST297, ST360), which have caused human infections. All the eight EPEC isolates were atypical EPEC; six serotypes and seven STs were found, and clinically relevant EPEC serotypes O26:H11, O103:H2, and O145:H28 were identified. Two STEC/ETEC (enterotoxigenic E. coli) hybrids and one EPEC/ETEC hybrid were observed, since they harbored sta1 and/or stb. The results revealed that food can act as a reservoir of STEC/EPEC with pathogenic potential, and had the potential ability to transfer antibiotic resistance and virulence genes.

Genetic characterization of extended-spectrum β-Lactamase- and carbapenemase-producing Escherichia coli isolated from Egyptian hospitals and environments

Over the past decades, Escherichia coli (E. coli) have acquired extensive resistance to antibiotics; especially β- lactams. This study aimed to investigate the frequency of Extended-spectrum β-lactamase (ESBL) and carbapenemase producers among E. coli isolates and their correlation with serotypes, phylogenetic background, and pathogenicity associated islands. A total of 105 E. coli strains were isolated and subjected to antimicrobial susceptibility testing against β-lactam antibiotics. All isolates showed a high resistance profile. Resistant isolates were tested for ESBL and carbapenemase production. Fifty-three and 18 isolates were positive for ESBL and carbapenemase producers, respectively. ESBL and carbapenemase genes were detected by PCR. TEM gene was the most prevalent gene among all isolates followed by SHV and CTX-M15. In carbapenemase-producers, OXA-48 and IMP were the predominant genes. Enteropathogenic E. coli (EPEC) and Enterohemorrhagic E. coli (EHEC) were the major producers of ESBL and carbapenemase, respectively as indicated by serodiagnosis. They were further assessed for the presence of pathogenicity islands (PAIs) and phylogenetic background. The most predominant DEC PAI and ExPEC PAI were HPI and IICFT073. Most clinically ESBL-producers were group D and B2 while environmentally ones were group B1 and A. On contrary, clinically carbapenemase-producers belonged to group C and D. In conclusion, our study confirms the importance of phylogenetic group D, B2, and C origin for antibiotic resistance in E. coli. Ultimately, our findings support the fact that environmental isolates contribute to the local spread of E. coli pathogenicity in Egypt and these isolates maybe serve as reservoirs for transmission of resistance.

Genomic Epidemiology of Shiga Toxin-Producing Escherichia coli Isolated from the Livestock-Food-Human Interface in South America

Simple Summary

Shiga toxin-producing Escherichia coli (STEC) are zoonotic pathogens that cause food-borne diseases in humans, where cattle and derived products play a key role as reservoirs and vehicles. We analyzed the genomic data of STEC strains circulating at the livestock-food-human interface in South America, extracting clinically and epidemiologically relevant information (serotypes, virulome, resistance genes, sequence types, and phylogenomics). This study included 130 STEC genomes obtained from cattle (n = 51), beef (n = 48), and human (n = 31) samples. The successful expansion of O157:H7 (ST11) and non-O157 (ST16, ST21, ST223, ST443, ST677, ST679, ST2388) clones is highlighted, suggesting common activities, such as multilateral trade and travel. Circulating STEC strains analyzed exhibit high genomic diversity and harbor several genetic determinants associated with severe illness in humans, highlighting the need to establish official surveillance of this pathogen that should be focused on detecting molecular determinants of virulence and clonal relatedness, in the whole beef production chain.

Abstract

Shiga toxin-producing Escherichia coli (STEC) are zoonotic pathogens responsible for causing food-borne diseases in humans. While South America has the highest incidence of human STEC infections, information about the genomic characteristics of the circulating strains is scarce. The aim of this study was to analyze genomic data of STEC strains isolated in South America from cattle, beef, and humans; predicting the antibiotic resistome, serotypes, sequence types (STs), clonal complexes (CCs) and phylogenomic backgrounds. A total of 130 whole genome sequences of STEC strains were analyzed, where 39.2% were isolated from cattle, 36.9% from beef, and 23.8% from humans. The ST11 was the most predicted (20.8%) and included O-:H7 (10.8%) and O157:H7 (10%) serotypes. The successful expansion of non-O157 clones such as ST16/CC29-O111:H8 and ST21/CC29-O26:H11 is highlighted, suggesting multilateral trade and travel. Virulome analyses showed that the predominant stx subtype was stx2a (54.6%); most strains carried ehaA (96.2%), iha (91.5%) and lpfA (77.7%) genes. We present genomic data that can be used to support the surveillance of STEC strains circulating at the livestock-food-human interface in South America, in order to control the spread of critical clones “from farm to table”.

Molecular typing and prevalence of extended-spectrum β-lactamase genes in diarrhoeagenic Escherichia coli strains isolated from foods and humans in Mashhad, Iran

AIMS

Present study was aimed to determine ESBL-encoding genes distribution in Diarrhoeagenic Escherichia coli (DEC) isolated from animal-source food products and human clinical samples in Mashhad, Iran. The strains were also further studied to analyse genotypic diversity and find genetic relationships between them.

METHODS AND RESULTS

The number of 85 DEC strains including 52 and 33 strains isolated from 300 food and 520 human stool samples, respectively. Randomly amplified polymorphic DNA (RAPD), and repetitive extragenic palindromic-PCR (rep-PCR) typing methods were used to track their genetic relationships. The ESBL-encoding genes prevalence was approximately 70% in both groups of isolates. The bla_TEM , bla_CTX-M and bla_SHV were prevalent in 67·1, 20 and 10·6% of isolates, respectively. The ESBL-positives showed significantly higher resistance rates to gentamicin, co-trimoxazole, tetracycline, aztreonam and chloramphenicol (P < 0·05). Fingerprinting patterns-based dendrograms divided DEC strains into separate clusters irrespective of their sources and pathotypes. In typing field, rep-PCR provided more discriminatory power (Simpson's index of diversity (SID) = 0·925) than RAPD (SID = 0·812).

CONCLUSION

Molecular similarity between certain animal-sourced food products and clinical sample strains supported food-borne transmission routes for genotypic elements such as ESBL-encoding genes.

SIGNIFICANCE AND IMPACT OF THE STUDY

Findings emphasize the importance of resistance issues, the need to improve treatment guidelines and routine surveillance of hygienic measures during food processing.

Etiology of acute gastroenteritis among children less than 5 years of age in Bucaramanga, Colombia: A case-control study

Background

Acute gastroenteritis (AGE) is a major cause of morbidity and mortality in children aged less than 5 years in low- and middle-income countries where limited access to potable water, poor sanitation, deficient hygiene, and food product contamination are prevalent. Research on the changing etiology of AGE and associated risk factors in Latin America, including Colombia, is essential to understand the epidemiology of these infections. The primary objectives of this study were to describe etiology of moderate to severe AGE in children less than 5 years of age from Bucaramanga, Colombia, a middle-income country in Latin American, and to identify the presence of emerging E. coli pathotypes.

Methodology/Principal findings

This was a prospective, matched for age, case-control study to assess the etiology of moderate to severe AGE in children less than 5 years of age in Bucaramanga, Colombia, South America. We tested for 24 pathogens using locally available diagnostic testing, including stool culture, polymerase chain reaction, microscopy and enzyme-linked immunoassay. Adjusted attributable fractions were calculated to assess the association between AGE and each pathogen in this study population. The study included 861 participants, 431 cases and 430 controls. Enteric pathogens were detected in 71% of cases and in 54% of controls (p = <0.001). Co-infection was identified in 28% of cases and in 14% of controls (p = <0.001). The adjusted attributable fraction showed that Norovirus GII explained 14% (95% CI: 10–18%) of AGE, followed by rotavirus 9.3% (6.4–12%), adenovirus 3% (1–4%), astrovirus 2.9% (0.6–5%), enterotoxigenic Escherichia coli (ETEC) 2.4% (0.4–4%), Cryptosporidium sp. 2% (0.5–4%), Campylobacter sp. 2% (0.2–4%), and Salmonella sp.1.9% (0.3 to 3.5%). Except for Cryptosporidium, all parasite infections were not associated with AGE. Three emergent diarrheagenic E. coli pathotypes were identified in cases (0.7%), including an enteroaggregative/enterotoxigenic E.coli (EAEC/ETEC), an enteroaggregative/enteropathogenic E.coli (EAEC/EPEC), and an emergent enteroinvasive E. coli with a rare O96:H19. No deaths were reported among cases or controls.

Conclusions/Significance

Norovirus and rotavirus explained the major proportion of moderate to severe AGE in this study. Higher proportion of infection in cases, in the form of single infections or co-infections, showed association with AGE. Three novel E. coli pathotypes were identified among cases in this geographic region.

Acute gastroenteritis (AGE) is a leading cause of mortality in children under 5 years of age in low- and middle-income countries (LMIC). The highest burden of AGE disease is concentrated in tropical areas where populations lack access to clean water, adequate sanitation and hygiene, making this condition a neglected disease. Limited information on etiology, associated malnutrition, and mortality among underserved communities makes difficult the development of strategies for AGE prevention and treatment. This case-control study among children less than 5 years of age in Bucaramanga, Colombia, revealed that viral followed by bacterial organisms explained the larger proportion of AGE, being norovirus the most common organism. The higher rate of infections and co-infections among cases compared to controls was associated with AGE. This study also reports the identification of three new E. coli pathotypes among cases designated as biofilm-forming enteroinvasive E. coli (BF-EIEC), enteroaggregative/enteropathogenic E. coli, and enteroaggregative/enterotoxigenic E. coli (EAEC/ETEC).

Whisky, microwave or hairdryer? Exploring the most efficient way to reduce bacterial colonisation on contaminated toothbrushes

Aims

It is the holiday season, but your toothbrush does not look very festive. It is damp and has been used and contaminated by someone else. To rectify this heinous crime, this study investigates the effectiveness of three household objects to disinfect toothbrushes.

Design

In-vitro study performed under conditions simulating everyday life.

Materials and methods

Twenty toothbrushes were contaminated using a mixture of saliva and trypticase soy broth containing Escherichia coli and Enterococcus faecalis. These contaminated toothbrushes were submerged in whisky, cooked in a microwave oven, or exposed to the hot air stream of a hairdryer, separately. Each treatment was performed on five toothbrushes for one minute. Untreated specimens (n = 5) served as controls. Toothbrushes were subsequently sonicated in sterile physiological saline, which was plated on selective agars. Bacterial counts were graded as low, medium, or high.

Results

Residual contamination was influenced by the disinfectant applied, both in E. coli (p <0.001) and E. faecalis (p = 0.019). Microwave cooking achieved highest decontamination, while whisky had no significant effect on bacterial counts over no treatment (p = 0.8). Hot air showed some limited effectiveness under current conditions.

Conclusions

Microwave oven cooking appears to be a simple, cheap, and effective way to reduce bacterial contamination of your toothbrush.

Prevalence of diarrheagenic Escherichia coli in animal products in Duhok province, Iraq

BACKGROUND

Diarrheagenic Escherichia coli (DEC) is regarded as a great public health concern all around the world causing diarrhoea which can be transmitted through food chain.

AIMS

This study aimed to determine the contamination level and exact distribution rate of DEC in food products consumed by human.

METHODS

Seven hundred and twenty samples of food from animal origin and fishes were analysed by conventional and molecular method for the presence of E. coli and two multiplex polymerase chain reaction (mPCR) for detection of DEC.

RESULTS

Two hundred and eighty-three E. coli isolates were detected. The classification of DEC by two multiplex PCR assay yielded 84 DEC pathotypes. Enterotoxigenic E. coli (ETEC) was detected at high rates (75%) followed by shiga-toxigenic E. coli (STEC) and enterohemorrhagic E. coli (EHEC) (each of 9.5%), enteroaggregative E. coli (EAEC) (3.5%) and atypical enteropathogenic E. coli (aEPEC) (about 2.3%). The highest number of DEC (n=26; 21.6%) was observed from beef carcasses in abattoir while the lowest number (n=7; 5.8%) was noticed from burger samples (P<0.01). Enterotoxigenic E. coli was widespread in local raw ground meat and fish surface swabs (P<0.001), EAEC (P<0.01), and EHEC (P<0.001) were only in beef carcasses swabs, STEC was more prevalent in both imported and local raw burger (P<0.01), while the isolates of aEPEC were from imported chicken carcasses (P>0.05).

CONCLUSION

High DEC contamination rate that was observed is attributed to the poor hygienic practices during food processing. Therefore, a superior hygienic application is required.

Molecular characterization of diarrheagenic Escherichia coli pathotypes: Association of virulent genes, serogroups, and antibiotic resistance among moderate-to-severe diarrhea patients

BACKGROUND

Diarrheagenic Escherichia coli (DEC) signifies as an important etiological agent of moderate-to-severe diarrhea. This study was primarily focused on molecular identification of DEC pathotypes; their association with serogroups and estimates of resistance profiles against different antibiotics regime.

METHODS

Five hundred seventy-two stool specimens from diarrhea patients were investigated for DEC pathotypes. Molecular pathotypes were identified by amplification of virulence genes associated with distinct pathotypes followed by sequencing. Diarrhea is a self-limiting disease, however, severity and persistence of infection suggest antibiotic use. Therefore, AST and MIC were determined against common antibiotic regimen. Correlations between molecular pathotypes and serogroups were analyzed by somatic "O" antigen serotyping.

RESULTS

The present findings reveal incidence of DEC as an etiological agent up to a level of 21% among all diarrheal age groups. DEC infection rate was higher in children. Enteropathogenic E. coliEPEC, a molecular pathotype of DEC, was found as a predominant pathotype with highest frequency of 13.7%. Two other molecular pathotypes enterotoxigenic E. coli (ETEC) and enteroaggregative E. coli (EAEC) accounted for 5.7% and 1.3%, respectively for all diarrhea incidences. Serological analysis deciphered somatic antigens O26, O2, and O3 as major serogroups identified among EPEC, ETEC, and EAEC pathotypes, respectively. All DEC pathotypes exhibited high levels of antibiotic resistance except for cotrimoxazole and norfloxacin.

CONCLUSION

Comprehensive molecular characterization of DEC pathotypes, their incidence estimates, and antibiogram patterns will help in ascertaining better diagnostic and therapeutic measures in management of diarrheal diseases.

Prevalence, antimicrobial resistance and multiple-locus variable-number tandem-repeat analysis profiles of diarrheagenic Escherichia coli isolated from different retail foods

Diarrheagenic E. coli (DEC) isolates were recovered from local retail markets and the Osaka Municipal Central Wholesale Market in Japan. Retail food samples were collected for analysis in Osaka Japan from 2005 to 2008 and consisted of 32 beef, 28 pork, 20 poultry, 136 fish, 66 fruits and vegetables and 51 ready-to-eat (RTE) food samples. A total of 82 DEC strains were recovered from 64 (19%) food samples with the highest prevalence in poultry (100%, 20/20), followed by pork (54%, 15/28), beef (28%, 9/32), fruits and vegetables (12%, 8/66), fish (6.6%, 9/136) and RTE foods (5.9%, 3/51). Most of the strains belonged to E. coli possessing the enteroaggregative E. coli (EAEC) heat-stable enterotoxin 1 (EAST1) gene (EAST1EC; n=62, P<0.0001) and enteropathogenic E. coli (EPEC; n=16, P<0.01), whereas only 1 strain belonged to Shiga toxin-producing E. coli (STEC), 1 to EAEC and 2 to enterotoxigenic E. coli (ETEC) strains. Of the 82 DEC isolates, 22 O and 13H serogroups were detected, including some specific serogroups (O91, O103, O115, O119, O126, and O157) which have been associated with human diarrheal infections. Phylogenetic group A and B1 were predominant among the DEC isolates. Antimicrobial resistance to tetracycline was most common (49%), followed by nalidixic acid (28%), ampicillin (24%), sulfamethoxazole/trimethoprim (20%), and cephalothin (18%). All isolates were susceptible to aztreonam. Of the resistant strains, 44% (22/50) demonstrated resistance to >3 antimicrobial agents. Isolates resistant to >5 antimicrobials were only found in the meat samples, while isolates from the fruits and vegetables as well as RTE foods showed resistance to only 1 or 2 antimicrobial agents. Sixty one percent of EAST1EC, 56% of EPEC and all of the EAEC and ETEC were resistant to at least 1 antimicrobial agent. Multiple-locus variable-number tandem repeat analysis (MLVA) was used in this study for genotyping of DEC. The 82 isolates collected for this study showed 77 distinct MLVA profiles located among 3 branches. The Simpson's Index of Diversity (D) was 99.9% at its highest. The high diversity of these food strains would suggest their originating from a variety of sources and environments. In conclusion, retail food samples in Japan were contaminated with DEC; EAST1EC, a putative DEC, were detected at high rates in poultry, pork and beef. Isolates resistant to >3 antimicrobials were found only in raw meat and fish. Food animals may act as the reservoir for multi-resistant bacteria. Due to the finding that nearly 1/3 of EAST1EC strains were resistant to >3 antimicrobials, additional surveillance for EAST1EC should be initiated.

Bacteriocins from lactic acid bacteria and their potential in the preservation of fruit products

Bacteriocins produced by lactic acid bacteria (LAB) are well-recognized for their potential as natural food preservatives. These antimicrobial peptides usually do not change the sensorial properties of food products and can be used in combination with traditional preservation methods to ensure microbial stability. In recent years, fruit products are increasingly being associated with food-borne pathogens and spoilage microorganisms, and bacteriocins are important candidates to preserve these products. Bacteriocins have been extensively studied to preserve foods of animal origin. However, little information is available for their use in vegetable products, especially in minimally processed ready-to-eat fruits. Although, many bacteriocins possess useful characteristics that can be used to preserve fruit products, to date, only nisin, enterocin AS-48, bovicin HC5, enterocin 416K1, pediocin and bificin C6165 have been tested for their activity against spoilage and pathogenic microorganisms in these products. Among these, only nisin and pediocin are approved to be commercially used as food additives, and their use in fruit products is still limited to certain countries. Considering the increasing demand for fresh-tasting fruit products and concern for public safety, the study of other bacteriocins with biochemical characteristics that make them candidates for the preservation of these products are of great interest. Efforts for their approval as food additives are also important. In this review, we discuss why the study of bacteriocins as an alternative method to preserve fruit products is important; we detail the biotechnological approaches for the use of bacteriocins in fruit products; and describe some bacteriocins that have been tested and have potential to be tested for the preservation of fruit products.