Molecular identification, Prevalence, and Phylogeny of Burkholderia cepacia Complex (BCC) Species in the Respiratory Tract of Hospitalized Patients

Burkholderia cepacia complex (Bcc) is a group of at least 25 phenotypically similar but genetically distinct and closely related bacterial species, causing severe pulmonary inflammation with high mortality rates among hospitalized patients. There was a gap in knowledge regarding the prevalence and accurate species status of Bcc strains in the Kurdistan region of Iraq. Therefore, the current study aimed to direct molecular identification and characterization of Bcc species in respiratory tract infections of hospitalized patients in Duhok province based on PCR amplification and sequencing of the Bcc recA gene. The investigation also targeted the detection of the epidemic marker BCESM ( esmR gene) and the transmissibility marker cblA gene. Results revealed that seven Bcc isolates were identified out of 309 sputum and oropharyngeal swabs. The overall prevalence rate of Bcc was 2.26%, with a higher percentage of isolation in sputum specimens (8.51%, 4/47) compared with oropharyngeal samples (1.14%, 3/262). The results of direct antibiotic susceptibility testing revealed that Imipenem was the most effective antibiotic against Bcc isolates (100% sensitive); contrastingly, Cefixime showed no effect on the isolates. Based on the recA gene sequencing, six Bcc species have been identified, including B. cepacia , B. multivorans , B. cenocepacia , B. anthina , B. contaminans , and B. lata , whose sequence identities ranged from 99.71–100%. Each of B. anthina (OR662134), B. lata (OR662135), B. cenocepacia (OR662137), and B. contaminans (OR662140) were recorded as the first identified and reported Bcc species in Iraq. The transmissibility marker was found in three isolates of the identified Bcc complex species (42.85%, 3/7). Also, B. cepacia was found to be a transmissible epidemic strain ( cblA +/ esmR +). Identifying transmissible and epidemic strains of the Bcc complex in this region puts hospitalized patients at high risk of cross-infection, which may require active surveillance and further investigation.