Which of the following does not describe Acinetobacter sp.?

• A. Infections associated with use of medical devices
• B. Generally coccobacillary in morphology
• C. Oxidase negative
• D. Commonly susceptible to most antimicrobials

Answer: (D)

Acinetobacter species are non-fermenting, gram-negative organisms that commonly appear as short, plump rods (often described as coccobacilli). They are a frequent cause of hospital-acquired infections, especially those linked to invasive devices such as ventilators, catheters, or lines. In the lab, they are oxidase negative, which helps distinguish them from other non-fermenters like Pseudomonas, which are oxidase positive.

A crucial clinical point is their antibiotic resistance profile. Acinetobacter spp. often acquire resistance determinants and are frequently resistant to multiple antibiotic categories, making them not commonly susceptible to most antimicrobials. This is why susceptibility testing is essential to guide effective therapy. The statements about device-associated infections, mesomorphic appearance as coccobacilli, and oxidase negativity align with Acinetobacter, while the idea that they are usually susceptible to most antibiotics does not fit, which is why that statement does not describe them.