Achromobacter

Background

Genus of aerobic, afermentative Gram-negative bacilli within the family Alcaligenaceae and order Burkholderiales
Oxidase-positive, catalase-positive, indole-negative, urease-negative, and DNase-negative
May be misidentified as other afermentative Gram-negative bacilli
Most notable species of clinical significance is Achromobacter xylosoxidans
Other species that have been isolated from clinical specimens include Achromobacter denitrificans, Achromobacter ruhlandii, Achromobacter piechaudii, Achromobacter animicus, Achromobacter mucicolens, Achromobacter pulmonis, Achromobacter insolitus, Achromobacter spanius, Achromobacter deleyi, Achromobacter aegreficans, Achromobacter insuavis, Achromobacter anxifer, Achromobacter dolens, and Achromobacter marplatensis

Commonly found causing chronic lung infections in patients with cystic fibrosis
Can also cause pneumonia and bacteremia, often associated with indwelling hardware
Rarely cause skin and soft tissue infections, urinary tract infection, intraabdominal infection, CNS infection, eye infection, and ear infection
Very rarely cause endocarditis and osteomyelitis

Intrinsically resistant to cephalosporins, aztreonam, azithromycin, and aminoglycosides
The most reliable agents are TMP-SMX, ceftazidime, piperacillin, and carbapenems (imipenem more than meropenem)
- However, there is increasingly resistant to carbapenems due to efflux pumps and metallo-beta-lactamases
May be susceptible to ticarcillin, cefepime, fluoroquinolones, doxycycline, tigecycline, and colistin
For MDR isolates, consider cefiderocol or eravacycline
- Less evidence for meropenem-vaborbactam and plazomicin, but may also work