Clinical Pearls & Morning Reports
Although the mortality among patients with campylobacter bacteremia who receive the appropriate treatment is relatively low, the risk of death is higher among immunocompromised hosts. Read the latest Case Record of the Massachusetts General Hospital.
Q. What are the morphologic features of campylobacter?
A. Although campylobacter literally means “curved rod,” Campylobacter jejuni and C. fetus may adopt a spiral form after a short incubation period in the laboratory, such as the incubation in a blood culture that has just turned positive. Indeed, a mixture of spiral forms with gull-wing forms and curved rods is consistent with the classic morphologic features of campylobacter.
Q. What factors influence the choice of antibiotic therapy for C. jejuni infection?
A. There is a high prevalence of fluoroquinolone resistance (approximately 25% in 2014) and a low prevalence of macrolide resistance (<5% in 2014) among C. jejuni isolates in the United States.
A: Exposure to campylobacter species, especially Campylobacter jejuni, is ubiquitous worldwide. In domesticated animals (notably poultry, cattle, sheep, swine, goats, dogs, and cats), the pathogen becomes a persistent member of the microbiome after it is ingested. Colonization of commercial poultry is common, and fecal contamination during processing is frequent enough that a large proportion of raw poultry in supermarkets is contaminated with C. jejuni. Clinical manifestations of C. jejuni infection most often involve a self-limited gastroenteritis, sometimes with bloody diarrhea. Bacteremia develops in less than 1% of patients with diarrheal illnesses due to C. jejuni.
A: Enterohepatic helicobacter species, such as Helicobacter cinaedi and H. fennelliae, were formerly classified as campylobacter species and are also reported to cause bacteremia with curved or spiral-shaped gram-negative rods, albeit rarely. Helicobacter-associated bacteremia may accompany cellulitis or gastroenteritis, and it occurs often but not exclusively in immunosuppressed patients. Leptospira species are spiral-shaped bacteria that are characterized by a terminal hook, but similar to treponema species, they are generally too thin to see on a Gram’s stain and are better visualized with the use of dark-field microscopy. Leptospirosis can cause severe acute illness in a healthy host, including fever with liver failure, kidney failure, and pulmonary hemorrhage (Weil’s syndrome). Anaerobiospirillum succiniciproducens is a motile gram-negative organism that forms extended spirals. Only a few dozen cases of infection with this pathogen have been reported, and the infection usually occurs in patients with liver disease, alcohol use, or diabetes. Affected patients usually present with a nonspecific illness that is characterized by fever, leukocytosis, and gastrointestinal distress.