Alcaligenes faecalis

Background

• Afermentative Gram-negative bacillus within the genue Alcaligenes
• Motile with a peritrichous flagella
• Oxidase positive, catalase positive
• Environmental organism found in soil and water as well as in the human gut microbiota

Clinical Manifestations

• In children, can cause neonatal sepsis, as well as otitis media, keratitis, and endophthalmitis
• In adults, can cause UTI including pyelonephritis, pneumonia, pancreatic abscess, diabetic foot infection, and osteomyelitis with bone abscess, and peritoneal dialysis-associated peritonitis

Management

• Most reliable antibiotics are imipenem, meropenem, and ceftazidime (about 66% susceptible), followed by ciprofloxacin and piperacillin-tazobactam (about 50% susceptible)

Further Reading

• Extensively drug-resistant Alcaligenes faecalis infection. BMC Infect Dis. 2020;20:833. doi: 10.1186/s12879-020-05557-8