Burkholderia cepacia complex (BCC) is a species complex consisting of Burkholderia cepacia and at least 20 different biochemically similar species of Gram-negative bacteria. They are catalase-producing and lactose-nonfermenting. Members of BCC are opportunistic human pathogens that most often cause pneumonia in immunocompromised individuals with underlying lung disease (such as cystic fibrosis or chronic granulomatous disease). Patients with sickle-cell haemoglobinopathies are also at risk. The species complex also attacks young onion and tobacco plants, and displays a remarkable ability to digest oil.

The group includes B. cepacia, B. multivorans, B. cenocepacia, B. vietnamiensis, B. stabilis, B. ambifaria, B. dolosa, B. anthina, B. pyrrocinia and B. ubonensis, among other species.

BCC is resistant to a number of common disinfectants, specifically povidone-iodine, triclosan, chlorohexidine, cetylpyridinium chloride, and quaternary ammoniums such as benzalkonium chloride. Concentrations used as preservatives in water-based pharmaceutical products are often not enough to kill BCC or even stop it from proliferating. Even higher-concentration versions of these biocides intended for disinfection, such as povidone-iodine solution for wound dressing and benzonium chloride wipes, may harbor live BCC if not sterilized using another method.

Burkholderia cepacia is also found in marine environments (marine sponges) and some strains of Burkholderia cepacia can tolerate high salinity. S.I. Paul et al. (2021) isolated and biochemically characterized salt tolerant strains of Burkholderia cepacia from marine sponges of Saint Martin's Island of the Bay of Bengal, Bangladesh.

BCC organisms are typically found in water and soil and can survive for prolonged periods in moist environments. They show a relatively poor virulence. Virulence factors include adherence to plastic surfaces (including those of medical devices) and production of several enzymes such as elastase and gelatinase. Also relevant might be their ability to survive attacks from neutrophils.

Person-to-person spread has been documented; as a result, many hospitals, clinics, and camps have enacted strict isolation precautions for those infected with BCC. Infected individuals are often treated in a separate area from uninfected patients to limit spread, since BCC infection can lead to a rapid decline in lung function and result in death.

BCC infection is a contraindication for lung transplantation and cystic fibrosis patients infected with BCC may be excluded from transplantation due to the increased mortality. Additionally, lung transplant recipients infected with B. cenocepacia are six times more likely to die within a year of transplantation than those infected with other BCC organisms.

Diagnosis of BCC involves culturing the bacteria from clinical specimens, such as sputum or blood. BCC organisms are naturally resistant to many common antibiotics, including aminoglycosides and polymyxin B. and this fact is exploited in the identification of the organism. The organism is usually cultured in Burkholderia cepacia agar (BC agar), which contains crystal violet and bile salts to inhibit the growth of Gram-positive cocci, and ticarcillin and polymyxin B to inhibit the growth of other Gram-negative bacilli. It also contains phenol red pH indicator which turns pink when it reacts with alkaline byproducts generated by the bacteria when it grows.^{[citation needed]}