RESUMO
Escherichia coli O157:H7 is an important food-borne and water-borne pathogen that causes hemorrhagic colitis and the hemolytic-uremic syndrome in humans and may cause serious morbidity and large outbreaks worldwide. People with bloody diarrhea have an increased risk of developing serious complications such as acute renal failure and neurological damage. The hemolytic-uremic syndrome (HUS) is a serious condition, and up to 50% of HUS patients can develop long-term renal dysfunction or blood pressure-related complications. Children aged two to six years have an increased risk of developing HUS. Clinical enteropathogenic Escherichia coli (EPEC) infections show fever, vomiting, and diarrhea. The EPEC reservoir is unknown but is suggested to be an asymptomatic or symptomatic child or an asymptomatic adult carrier. Spreading is often through the fecal-oral route. The prevalence of EPEC in infants is low, and EPEC is highly contagious in children. EPEC disease in children tends to be clinically more severe than other diarrheal infections. Some children experience persistent diarrhea that lasts for more than 14 days. Enterotoxigenic Escherichia coli (ETEC) strains are a compelling cause of the problem of diarrheal disease. ETEC strains are a global concern as the bacteria are the leading cause of acute watery diarrhea in children and the leading cause of traveler's diarrhea. It is contagious to children and can cause chronic diarrhea that can affect the development and well-being of children. Infections with diarrheagenic E. coli are more common in African countries. Antimicrobial agents should be avoided in the acute phase of the disease since studies showed that antimicrobial agents may increase the risk of HUS in children. The South African National Veterinary Surveillance and Monitoring Programme for Resistance to Antimicrobial Drugs has reported increased antimicrobial resistance in E. coli. Pathogenic bacterial strains have developed resistance to a variety of antimicrobial agents due to antimicrobial misuse. The induced heavy metal tolerance may also enhance antimicrobial resistance. The prevalence of antimicrobial resistance depends on the type of the antimicrobial agent, bacterial strain, dose, time, and mode of administration. Developing countries are severely affected by increased resistance to antimicrobial agents due to poverty, lack of proper hygiene, and clean water, which can lead to bacterial infections with limited treatment options due to resistance.
RESUMO
OBJECTIVES: The emergence of antimicrobial-resistant livestock-associated Escherichia coli represents a great public health concern. Here we report the draft genome sequences of two multidrug-resistant livestock-associated E. coli strains MEZEC8 and MEZEC10 isolated from sheep in South Africa. METHODS: Genomic DNA of E. coli strains MEZEC8 and MEZEC10 was sequenced using an Illumina MiSeq platform. Generated reads were trimmed and de novo assembled. The assembled contigs were analysed for antimicrobial resistance genes, chromosomal mutations and extrachromosomal plasmids, and the sequence type (ST) was determined by multilocus sequence typing (MLST). To compare strains MEZEC8 and MEZEC10 with other previously published sequences of E. coli strains, raw read sequences of E. coli from livestock were downloaded from the NCBI's Sequence Read Archive and all sequence files were treated identically to generate a core genome bootstrapped maximum likelihood phylogenetic tree. RESULTS: Antimicrobial resistance genes were detected in MEZEC8 and MEZEC10 conferring resistance to tetracycline and macrolides. MEZEC10 harboured two extrachromosomal plasmids (pO111 and Incl2), while MEZEC8 did not contain any extrachromosomal plasmids. Strain MEZEC8 belonged to serotype H25:O9 and ST58, whereas strain MEZEC10 belonged to serotype H49:O8 and ST1844. CONCLUSION: The genome sequences of E. coli strains MEZEC8 and MEZEC10 will serve as a reference point for molecular epidemiological studies of antimicrobial-resistant livestock-associated E. coli in Africa. In addition, this study allows in-depth analysis of genomic structure and will provide valuable information enabling us understand the antimicrobial resistance of livestock-associated E. coli.