Achromobacter

Achromobacter xylosoxidans

Achromobacter is a genus of bacteria belonging to the family Alcaligenaceae. This genus comprises Gram-negative, oxidase-positive, motile rods that are widely distributed in the environment, particularly in soil and water. Achromobacter species are opportunistic pathogens capable of causing a variety of infections in humans, especially in individuals with compromised immune systems.

Characteristics

Achromobacter species are characterized by their ability to grow in aerobic conditions. They are non-fermentative on most carbohydrates, which distinguishes them from many other Gram-negative bacteria. The cells are typically motile by means of peritrichous flagella, which contribute to their ability to colonize various environments and hosts.

Pathogenicity

While Achromobacter is primarily found in environmental sources, it has been increasingly recognized as an opportunistic pathogen in humans. It can cause a range of infections, including bacteremia, pneumonia, urinary tract infections, and wound infections. Achromobacter xylosoxidans is the most well-known species within this genus in terms of its clinical significance. It has been isolated from patients with cystic fibrosis and is known to cause chronic lung infections in these individuals. The treatment of infections caused by Achromobacter can be challenging due to its intrinsic resistance to multiple antibiotics.

Diagnosis and Treatment

The diagnosis of Achromobacter infections involves the isolation and identification of the bacterium from clinical specimens, such as blood, sputum, or urine. Laboratory tests typically include culture techniques and biochemical testing to differentiate Achromobacter from other non-fermentative Gram-negative bacteria. Molecular methods, such as PCR (Polymerase Chain Reaction), may also be employed for more rapid and accurate identification.

Treatment of Achromobacter infections requires careful selection of antibiotics due to the organism's inherent resistance to many commonly used antimicrobial agents. Antibiotic susceptibility testing is crucial to determine the most effective treatment options. In some cases, combination therapy may be necessary to overcome resistance and effectively treat the infection.

Epidemiology

Achromobacter species are widely distributed in the environment, which facilitates their occasional transmission to humans, leading to infection. The incidence of Achromobacter infections is relatively low compared to other opportunistic pathogens, but these infections can be significant in immunocompromised individuals, such as those with cystic fibrosis, cancer, or undergoing immunosuppression therapy.

Prevention

Prevention of Achromobacter infections primarily involves measures to reduce exposure to the bacterium in hospital settings, where immunocompromised patients are at higher risk. This includes strict adherence to infection control practices, such as hand hygiene and the sterilization of medical equipment. For individuals with cystic fibrosis or other conditions that increase the risk of lung infections, regular monitoring and early intervention at the sign of respiratory symptoms can help prevent the establishment of chronic infections.