CTX-M-15 Producing Escherichia coli Sequence Type 361 and Sequence Type 38 Causing Bacteremia and Umbilical Infection in a Neonate Foal.

This study discusses a case of a newborn foal suffering from a severe bacterial infection caused by two different strains of Escherichia coli (E. coli), leading to its eventual euthanasia despite aggressive medical intervention.

Research Study Explained

• The research study revolves around a case of an 18-hour-old Tennessee walking horse foal. The foal was referred for medical attention due to visible physical distress such as weakness and abdominal pain. Among the observable conditions were dehydration, a distended abdomen, and uveitis (an inflammation of the eye).
• Initial medical investigation through blood analysis revealed the foal was suffering from leukopenia (low white blood cell count), toxic neutrophils, and left shift (an increase in immature neutrophil cells in the blood).
• As time went on, the situation got worse as the foal developed bloody diarrhea and gastric reflux. The combination of the symptoms led to a diagnosis of sepsis (a severe response to infection) and enterocolitis (an acute or chronic inflammation of the digestive tract).
• Medical intervention was applied, including the use of intravenous fluids, plasma, antibiotics (ceftriaxone and metronidazole), partial parenteral nutrition, pain relief medicine (flunixin meglumine), and ophthalmic drops for the eye inflammation.
• An ultrasound of the foal’s umbilicus revealed a fluid pocket adjacent to the umbilical vein. This discovery necessitated a surgical procedure known as omphalectomy (removal of the umbilicus).
• Medical experts cultured the foal’s blood and umbilicus. Laboratory results showed the presence of two multidrug-resistant strains of E. coli, each producing a unique enzyme called extended-spectrum β-lactamase (ESBL) that allows the bacteria to resist antibiotics. These were identified as ST38 from the umbilicus and ST361 from the blood.
• Given the presence of drug-resistant bacteria, the initial antibiotic treatment was replaced with a regimen of imipenem and amikacin.
• Unfortunately, despite medical intervention, the health of the foal deteriorated and it was euthanized. A subsequent postmortem examination revealed severe ulcerative enteritis, an intestinal perforation, and acute renal infarcts (areas of dead tissue due to inadequate blood supply).

Research Summary and Implication

• This case study emphasizes the potential for severe and fatal outcomes when newborn foals become infected with ESBL-producing E. coli strains. The researchers recommended that sepsis caused by different ESBL-producing E. coli strains should be treated as a serious medical condition requiring immediate investigation and appropriate treatment.