Abstract
The Burkholderia cepacia complex (BCC) comprises approximately thirty-five species of Gram-negative bacteria that are known to cause infections in humans, particularly in immunocompromised patients. While BCC is most commonly associated with respiratory infections in people with cystic fibrosis (CF), it can also lead to a range of infections in individuals without CF. The goal of the current study was to molecularly identify and characterize BCC species that are responsible for infections in hospitalized and non-hospitalized patients in Erbil province, using polymerase chain reactions (PCR) to amplify and sequence the recombinance A gene (recA) gene. This study explored the prevalence, species distribution, antibiotic resistance patterns, biofilm formation and investigated three virulence genes of BCC isolates.
Out of the 101 clinical samples, including urine, respiratory tract (tracheal aspirate and sputum), tissue, blood, burns and wound swabs, collected during the period extended from September 2024 to February 2025, 20 isolates (19.8%) were identified as BCC. Through sequencing of the recA gene, four species from the BCC group have been identified: B. cenocepacia, B. cepacia, B. contaminans, and B. anthina. Among these, B. cenocepacia stands out as the most prevalent, making up 75% of the cases. The infections mainly affecting the urinary tract (60%).
The susceptibility of the bacterial isolates under investigation to various antibiotics was screened. Out of 20 isolates, 70% of them were multi-drug resistant (MDR). Antimicrobial susceptibility testing showed a high resistance to ceftazidime 19 (95%) and moderate resistance to fluoroquinolones 12 (%60). However, meropenem, cotrimoxazole, and doxycycline proved to be the most effective treatments. To investigate biofilm production by BCC, the significant proportion of BCC formed strong biofilm, which was 45% by using microtiter plate method and 60% by using congo red agar method. Siderophore production was phenotypically detected using Chrome azurol s agar, with B. cenocepacia showing the highest production rate (88.9%).
Polymerase chain reactions was used to detect three of the virulence genes, Quroum-sensing regulator protein gene(CepR )regulates quorum sensing and biofilm formation, flagellin gene (FliC), and siderophore related gene (OrbJ). FliC gene was detected in eighteen isolates, however CepR and OrbJ were not detected in half of the isolates. These results highlight the significant clinical challenges posed by BCC infections, particularly in clinical samples of non-cystic fibrosis patients, and emphasize the need for better diagnostic methods and treatment options. It is recommended to conduct further studies on how the virulence genes expressed and explored strategies to inhibit biofilm formation. This will help deepen our understanding of the mechanisms behind infections and lead to the development of new treatments.
