Escherichia Coli Infections Clinical Presentation

Acute bacterial meningitis

Newborns with E coli meningitis present with fever and failure to thrive or abnormal neurologic signs. Other findings in neonates include jaundice, decreased feeding, periods of apnea, and listlessness.

Patients younger than 1 month present with irritability, lethargy, vomiting, lack of appetite, and seizures.

Those older than 4 months have neck rigidity, tense fontanels, and fever.

Older children and adults with acute E coli meningitis develop headache, vomiting, confusion, lethargy, seizures, and fever.

In rare cases, persons with a history of open CNS trauma or multiple neurological procedures develop S stercoralis hyperinfection.

Because patients who have undergone neurosurgery frequently have headaches, nuchal rigidity, and a decreased level of consciousness secondary to the surgery, signs may be difficult to interpret.

The differential diagnoses of acute E coli meningitis include sepsis, seizure disorder, brain abscess, ruptured aneurysm, and neonatal tetanus.

Pneumonia

Patients with E coli pneumonia usually present with fever, shortness of breath, increased respiratory rate, increased respiratory secretions, and crackles upon auscultation.

Findings include bronchopneumonia on chest radiography, commonly in the lower lobes. Many patients are intubated and have fever, an increased respiratory rate, and increased respiratory secretions.

The differential diagnoses of E coli pneumonia include congestive heart failure and pulmonary embolism. Other pneumonias caused by gram-negative bacilli are difficult to distinguish clinically.

Intra-abdominal infections

Patients with E coli cholecystitis or cholangitis develop right upper quadrant (RUQ) pain, fever, and jaundice. In severe cases, hypotension and confusion also develop. Cholecystitis manifests with fever (>102°F). Cholangitis manifests with fever (>102°F), shaking chills, and RUQ pain and can be complicated by hepatic abscess. Amebic liver abscess, Echinococcus cyst, and Klebsiella and Enterococcus infections are difficult to distinguish clinically. Anaerobes are observed in patients with diabetes and acute acalculous cholecystitis.

Patients with E coli intra-abdominal abscesses may have low-grade fever, but the spectrum of clinical presentations ranges from nonspecific abdominal examination findings to frank septic shock. Peritonitis manifests as localized pain with rebound and fever. The presentation ranges from low-grade fever with abdominal tenderness, weakness, malaise, and anorexia to hypoxemia and hypotension. The infection is usually polymicrobial with E coli and other gram-negative bacilli and anaerobes. The differential diagnoses include retroperitoneal hematoma and septic thrombophlebitis.

Enteric infections

Patients with E coli traveler's diarrhea (ie, watery nonbloody diarrhea; caused by enterotoxigenic E coli [ETEC] or enteroaggregative E coli [EAggEC]) may appear to be dehydrated. Traveler's diarrhea is observed in young healthy travelers to tropical countries and is watery diarrhea without polymorphonuclear (PMN) leukocytes. The differential diagnoses of E coli traveler's diarrhea include rotavirus infection, Norwalk virus infection, Salmonella infection, and Campylobacter diarrhea.

Patients with E coli childhood diarrhea (ie, watery nonbloody diarrhea; caused by EAggEC, enteroadherent E coli [EAEC], or enteropathogenic E coli [EPEC]) may also appear to be dehydrated. These infections produce a noninflammatory watery diarrhea observed especially in children. The differential diagnoses of E coli childhood diarrhea include Vibrio cholerae infection and Rotavirus infection.

In May, June, and July, 2011 an outbreak of gastroenteritis caused by Shiga-toxin–producing E coli was seen in Germany. The majority of patients were adults and 22% of the cases developed hemolytic–uremic syndrome The outbreak strain was typed as an enteroaggregative Shiga-toxin–producing E coli O104:H4, producing extended-spectrum beta-lactamase. The consumption of sprouts was identified as the most likely vehicle of infection. This outbreak was different as it was caused by EAggEC that produced a Shiga toxin and it exemplifies the threat posed by foodborne pathogens with their propensity to cause large common-source outbreaks.^{[2, 3]}

Patients with E coli dysentery (caused by enteroinvasive E coli [EIEC] or enterohemorrhagic E coli [EHEC]) have fever, bloody diarrhea, and dehydration. Intestinal mucosa produces a significant inflammatory response. Clinically, patients with E coli dysentery present with fever and have blood and PMN leukocytes in their stool. The differential diagnoses of E coli dysentery include shigellosis and amebic dysentery.

Patients with E coli HUS (caused by EHEC) have fever, bloody diarrhea, dehydration, hemolysis, thrombocytopenia, and uremia requiring dialysis. Symptoms of E coli HUS range from asymptomatic to nonbloody diarrhea to bloody diarrhea, renal failure, microangiopathic hemolytic anemia, thrombocytopenia, and CNS manifestations. The differential diagnoses of E coli HUS include Shigella infections, Clostridium difficile enterocolitis, ulcerative colitis/Crohn disease, ischemic colitis, diverticulosis, and appendicitis.

Urinary tract infections

Acute E coliurethral syndrome manifests as low-grade fever and dysuria. Patients present with dysuria, increased frequency, and urgency, and they have colony counts. S saprophyticus infection is observed in 5-10% of cases, especially in sexually active women, associated with alkaline pH and microscopic hematuria. Less commonly, patients have Proteus mirabilis, Klebsiella, or Enterococcus infections. Approximately 15% of cases are culture-negative; these are due to Chlamydia trachomatis, Ureaplasma urealyticum, or Mycoplasma hominis infection.

Patients with symptomatic E coli UTI have dysuria and may have low-grade fever.

Patients with E coli pyelonephritis or complicated UTI present with localized flank or low back pain, high fever (>102°F), and urinary frequency and urgency. Findings also include rigors, sweating, headache, nausea, and vomiting. It can be complicated by necrotizing intrarenal or perinephric abscess, which manifests as a bulging flank mass or pyelonephritis that does not respond to antibiotics. Patients with diabetes or urinary tract obstruction can also develop bacteremia and septicemia. The differential diagnoses include psoas abscess appendicitis, ectopic pregnancy, and ruptured ovarian cyst.

Patients with E coliacute prostatitis or prostatic abscess have chills, sudden fever (>102°F), and perineal and back pain with a tender, swollen, indurated, and hot prostate. Acute prostatitis also manifests as dysuria, urgency, and frequent voiding. Some patients may have myalgia, urinary retention, malaise, and arthralgia. If the patient does not respond to antibiotics, consider prostatic abscess and confirm it with imaging studies. Treatment consists of open surgical or percutaneous drainage.

Patients with E coli prostatic abscess, which manifests as a complication of acute prostatitis, have a high fever despite adequate antimicrobial therapy and fluctuance of the prostate upon rectal examination.

The differential diagnoses of E coli acute prostatitis or prostatic abscess can include chronic bacterial prostatitis, which is usually asymptomatic; some patients may have frequency, dysuria, and nocturia with pain and discomfort in the perineal, suprapubic, penile, scrotal, or groin region. Also included are infected prostatic calculi, which can cause recurrent UTIs and should be surgically removed. Finally, nonbacterial prostatitis is also a differential diagnostic possibility and manifests as perineal, suprapubic scrotal, low back, or urethral tip pain.

Additionally, patients with E coli renal abscess present with fever, pleuritic chest pain secondary to diaphragmatic irritation, and flank pain, with or without a palpable abdominal mass.^[2]

Acute bacterial meningitis

E coli is a common cause of meningitis in newborns and is associated most frequently with prematurity.

E coli meningitis can be acquired during birth or can develop secondarily after infection in another body site, such as in cases of omphalitis, upper respiratory tract infection, or infected circumcision wound.

In adults, E coli meningitis is not uncommon in those who have undergone multiple neurological procedures or who have had open CNS trauma.

Immunosuppressed patients receiving corticosteroid therapy and those with S stercoralis hyperinfection are also at risk for E coli meningitis.

Pneumonia

E coli pneumonia is often preceded by colonization of the upper respiratory tract (eg, nasopharynx).

Community-acquired E coli pneumonia has been reported in rare cases.

Intra-abdominal infections

Along with Enterococcus faecalis and Klebsiella species, E coli is one of the most common organisms associated with cholecystitis/cholangitis and intra-abdominal abscesses, as part of polymicrobial flora including anaerobes.

E coli cholecystitis/cholangitis manifests as the classic Charcot triad of fever, pain, and jaundice in 70% of cases. Fever is the most common finding (95%). RUQ pain and jaundice may be absent if no obstruction is present.

In late stages, hypotension, confusion, and renal failure are observed.

Liver abscess can develop as a complication of a E coli biliary tract infection.

The findings of E coli intra-abdominal abscesses are less conspicuous than those of diffuse peritonitis. The patient may have only low-grade fever, generalized malaise, and anorexia. In the postoperative patient who may have a distended and tender abdomen, clinical diagnosis of E coli intra-abdominal abscess may be difficult.

Enteric infections

Traveler's diarrhea usually occurs in persons from industrialized countries who visit tropical or subtropical regions and develop abdominal cramps and frequent explosive bowel movements 1-2 days after exposure to contaminated food or water.

E coli enterotoxin acts on the GI mucosa, leading to an outpouring of copious fluid from the small bowel.

The symptoms usually last 3-4 days and are self-limited.

Large fluid loss may result in dehydration.

EIEC infections are rare and manifest as bloody diarrheal stool containing PMN leukocytes. Patients usually have fever, abdominal cramping, and tenesmus lasting 5-7 days.

Childhood diarrhea is due to EPEC strains and usually occurs in underdeveloped countries or nursery outbreaks. The volume of diarrhea is less than that with ETEC strains, and no inflammatory cells are found in the diarrheal fluid. The child may experience fever, and diarrhea lasts longer than 2 weeks in some cases.

Infection with EHEC strains of the serotype 0157:H7 begin as watery diarrhea followed by grossly bloody stool without inflammatory PMN cells and results in HUS in 10% of cases, characterized by hemolysis, thrombocytopenia, uremia (possibly requiring dialysis), and death in some cases.

EAggEC and EAEC cause clinical illnesses that are not yet well characterized and are associated with persistent diarrhea in children.

Urinary tract infections

E coli is the leading cause of community-acquired and nosocomial UTI.

Females are predisposed to UTI because of their anatomy and changes during sexual maturation, pregnancy, and childbirth.

Young boys with posterior urethral valves are also predisposed to UTIs, as are elderly men with prostatic hypertrophy.

Other risk factors include catheterization or mechanical manipulation, obstruction, or diabetes.

Patients with E coli UTI present with a wide spectrum of symptoms, ranging from asymptomatic cystitis to pyelonephritis/perinephric abscess.

Urethral syndrome is a term used to describe symptoms of dysuria with colony counts less than 100,000 colony-forming units/mL of urine.

Uncomplicated E coli acute cystitis may manifest as low-grade fever, dysuria, and increased urinary frequency.

Acute pyelonephritis manifests as high-grade fever (>102°F) and costovertebral tenderness.

Acute prostatitis manifests as a sudden onset of fever and chills with perineal and low back pain.

Perinephric abscess may manifest as a bulging flank mass. GI symptoms such as nausea and vomiting are more likely in elderly persons. Patients with bacteremia secondary to an obstructed urinary catheter may present with decreased urine output.

Prostatic abscess can occur as a complication of acute prostatitis, notably in patients with diabetes mellitus, and should be considered in patients with acute prostatitis or UTI that is not improving with adequate antimicrobial therapy.

Other infections

E coli bacteremia can lead to septic shock, manifesting as hypotension and fever (in some cases, with hypothermia rather than fever). It may be complicated by uremia, hepatic failure, acute respiratory distress syndrome, stupor or coma, and death. Non–life-threatening E coli bacteremia may manifest as a sudden onset of fever and chills, tachycardia, tachypnea, and mental confusion. In cases of E coli UTI with urinary tract obstruction, bacteremia or septicemia may ensue.

A retrospective study determined risk factors for mortality in patients with fluoroquinolone-resistant E coli. Results show fluoroquinolone resistance, cirrhosis, and cardiac dysfunction independently predicted mortality.^[4]

Several cases of E coliendophthalmitis have been reported in patients with diabetes who have UTI or pyelonephritis.^[5]

Table. Differential Diagnoses of E coli Infection (Open Table in a new window)