A Decade-Long Study Focused on the Clinical and Microbiological Assessment of Patients Infected by <i>Achromobacter</i> Species

Abstract

Background: Achromobacter species is a motile, aerobic, oxidasepositive, non-fermentative Gram-negative bacillus. This microorganism is widely distributed in the environment and is most frequently associated with healthcare-associated infections. Methods: A retrospective evaluation was conducted on the patients' demographic information, co-morbid conditions, laboratory results, antimicrobial susceptibilities, and treatments. Results: The study included 154 patients along with their clinical isolates. The majority of Achromobacter species isolates were from surgical clinics (43%). A history of immunosuppressive disease or treatment was present in 40% of the individuals. Polymicrobial infections were identified in 50 patients, and a total of 18 patients (12%) died within 28 days. Trauma was less frequent (8% vs. 16%; P = 0.035), and the rate of chronic disease was lower (58% vs. 75%; P = 0.032) among patients with polymicrobial infections. These patients had a higher occurrence of abscess samples (68% vs. 36%; P < 0.001) and a lower 28-day mortality rate (4% vs. 18%; P = 0.037). Achromobacter spp. was isolated from blood cultures in 45 patients, with higher rates of hypertension (22% vs. 8.3%; P = 0.017) and coronary artery disease (45% vs. 7.3%; P = 0.003). Meropenem usage was more common in patients with bacteremia (29% vs. 11%; P = 0.006). The mortality rate was higher in the bacteremic patient group than in the non-bacteremic group (20% vs. 10.5%; P = 0.139). Conclusions: Achromobacter spp. are frequently isolated from immunocompromised patients, but they can also be part of polymicrobial infections, especially in wound or abscess samples from surgical clinics. This is the first study linking polymicrobial Achromobacter spp. abscesses to reduced mortality. It has been observed that the mortality rate is higher in bacteremic patients even when broad-spectrum antibiotics are used.