Is there a cure for E. coli?
With the increasing frequency and consistency of E. coli outbreaks around the world over the last few decades, there has been an increase in people’s level of interest in the subject.
This article, among others, aims at providing an answer to the question of a cure and treatment options for E. coli infections.
Introduction
E.coli is an abbreviation of the Gram-negative, rod-shaped, facultative anaerobic bacterium – Escherichia coli. This very diverse and important bacterium has its niche in the gastrointestinal tract (GIT) of humans and other warm-blooded animals, including – goats, birds, dogs, pigs, bats, goats, sheep, and cattle (the main reservoirs).
Most E. coli strains are harmless commensals and play vital roles like supplying their host with vitamin K, maintaining the normal gut flora, and fighting off pathogenic microbes, including pathogenic E. coli. Some are, however, harmful, and have become pathogenic by acquiring virulence factors.
These types of E. coli are known as pathogenic E. coli. Pathogenic E. coli can cause diarrhea, urinary tract infections (UTIs), respiratory illness, pneumonia, and other illnesses.
Pathogenic E. coli
Certain isolates of Escherichia coli have been implicated in a wide range of diseases that affect both animals and humans worldwide. To date, eight pathovars and their mechanisms of disease have been extensively studied. Although other pathovars have been identified, their mechanisms of pathogenesis are not yet well defined.
The eight well-defined E. coli pathovars can be broadly classified as either diarrhoeagenic E. coli or extraintestinal E. coli (ExPEC).
The diarrhoeagenic E. coli (which consists of six pathovars) include:
- Enteropathogenic E. coli (EPEC),
- Enterohaemorrhagic E.coli (EHEC),
- Enterotoxigenic E. coli (ETEC)
- Enteroinvasive E.coli (EIEC; including Shigella),
- Enteroaggregative E.coli (EAEC) and
- Diffusely adherent E.coli (DAEC). While
The extraintestinal E. coli (ExPEC) are:
- Uropathogenic E. coli (UPEC) and
- Neonatal meningitis E. coli (NMEC)
Enteropathogenic E. coli (EPEC)
These are important diarrheal pathogens in children. The most common symptoms of EPEC illness are watery diarrhea, abdominal pain, nausea, vomiting, and fever.
In addition to humans, EPEC can also infect animals such as cattle, dogs, cats, and rabbits. EPEC belongs to a group of pathogenic bacteria capable of causing A/E (attaching and effacing) lesions on the surface of their host’s intestinal epithelium.
Shiga toxin-producing E. coli/Enterohemorrhagic E. coli (STEC/EHEC)
Escherichia coli carrying the stx gene to produce Shiga toxins (Stxs) are defined as Shiga-toxin-producing E. coli (STEC), also known as verocytotoxin-producing E. coli (VTEC).
Strains of STEC can cause hemorrhagic colitis (HC) and are commonly referred to as Enterohaemorrhagic E. coli (EHEC).
There are many serotypes of STEC such as O26, O111, O121, and O157 in which serotype O157:H7 is the most studied, and provides much of the information of what is today known about E. coli.
Transmission of STEC infection mainly occurs through eating or handling contaminated food and coming into contact with infected animals.
Also, person-to-person transmission is possible through close contact. The symptoms of STEC infection in humans are watery diarrhea, hemorrhagic colitis (HC), hemolytic uremic syndrome (HUS), fever, abdominal cramping, and vomiting.
General treatment for STEC/EHEC is oral rehydration therapy and antibiotic therapy.
Shigella/Enteroinvasive E. coli (EIEC)
EIEC is closely related to Shigella spp. and causes bacillary dysentery (also called shigellosis) in humans.
Enteroinvasive E. coli (EIEC) and Shigella strains have the ability to invade the human mucosa of the colon, M cells, macrophages, and epithelial cells.
The symptoms of Shigella/EIEC infection range from mild watery diarrhea to severe inflammatory bacillary dysentery characterized by strong abdominal cramps, fever, chills, and stools containing blood and mucus.
Severe symptoms can even be fatal and severe life-threatening complications, including megacolon, intestinal perforation, peritonitis, pneumonia, and HUS, can occur.
Enteroaggregative E. coli (EAEC)
EAEC strains are important causative agents of “traveler’s diarrhea” and cause persistent diarrhea in immune-compromised children.
The symptoms of EAEC infection are often watery diarrhea with mucus and are accompanied by fever, vomiting, and abdominal pain. The EAEC infection treatments are oral rehydration therapy and antimicrobial therapy.
Antibiotics are useful for treating cases of traveler’s diarrhea. However, antibiotic resistance to EAEC is increasing around the world.
Enterotoxigenic E. coli (ETEC)
In developing countries and semitropical areas such as Latin America, the Caribbean, southern Asia, and Africa, Enterotoxigenic E. coli (ETEC) is a major cause of traveler’s diarrhea and the childhood diarrhea pathogen.
The typical clinical symptoms of ETEC infection are often watery diarrhea, abdominal pain, nausea, vomiting, and fever, with symptoms typically lasting for about 3–5 days.
ETEC infection is acquired by ingestion of contaminated food or water. Oral rehydration therapy and antibiotic therapy are very effective for ETEC infection diarrhea. In recent years, many reports have indicated that antimicrobial-resistant ETEC strains are increasing worldwide.
Uropathogenic Escherichia coli (UPEC)
UBEC infections account for about 80% of all UTIs (about 150 million people around the world suffer from UTIs every year), causing cystitis in the bladder and acute pyelonephritis in the kidneys.
UPEC are highly versatile pathogens that are able to commensally colonize the human gastrointestinal tract, while also opportunistically causing disease in the urinary tract.
While antibiotics continue to be useful in the treatment and care of UBEC infections, the efficacy of antibiotic treatment depends on the identification and antimicrobial resistance pattern of uropathogens responsible for UTIs.
Neonatal meningitis Escherichia coli (NMEC)
NMEC is a common inhabitant of the gastrointestinal tract and the most frequent cause of Gram-negative-associated meningitis in newborns. Fatality rates can approach 40%, and survivors are usually burdened with severe neurological sequelae.
How are E.coli infections spread?
E.coli are mainly spread through the oral-fecal route. This may be via:
Person to person: E. coli is spread from person to person when people don’t wash their hands thoroughly with soap and water after making use of the restroom or coming in contact with contaminated excreta, and they go about touching other people.
This then serves as an avenue for the invisible E. coli to get into the mouth, either from the food they eat or from putting their fingers in their mouth.
E. coli spreads from person to person this way in settings such as daycare centers, nursing homes, or between couples. Also, in animal farms or pet zoos, people can contract the infection by touching contaminated animal furs.
Water: People also contract E.coli infection when they swallow contaminated water while swimming or by drinking poorly treated water.
Food: Another means by which people contract E.coli infection is by eating uncooked or poorly cooked infected meat; improperly washed fruits and vegetables; and unpasteurized milk, juices, and cider.
Prevention and Treatment/cure of E.coli infections.
In general, E. coli infections are prevented by improved environmental sanitation and personal hygiene and are treatable by oral or intravenous rehydration, antidiarrheal, and antibiotics, depending on the strain and type of infection.
Early diagnosis is very important to the successful management and/or treatment of any case of E. coli infection, as it shares similar symptoms with other bacterial infections like Salmonella strains, Citrobacter freundii, Shigella spp, and Campylobacter.
Children, especially infants, who are suspected of having E.coli infection, can receive intravenous antibiotic treatment until the organism has been isolated from cultures. A more specific antibiotic can then be prescribed when susceptibility results become available.
Usually, the length of time of treatment is based on the clinical response of the patient and the site of the infection.
The usual duration of therapy is 10 to 14 days for uncomplicated bacteremia, 7 to 14 days for UTIs, and a minimum of 21 days for meningitis. Treatment of E. coli-associated diarrhea is primarily supportive, with particular attention paid to the status of hydration and electrolyte balance.
Most people recover after 5 to 7 days when it is a case of non-bloody diarrhea and may self-resolve without further complication. However, around 5–10% of people with STEC O157 infection develop hemolytic uremic syndrome (HUS), a type of kidney failure and a life-threatening complication. Many people with HUS require dialysis; some suffer permanent kidney damage or die.
Always consult with your healthcare provider at the emergence of any symptoms for proper medical attention.