Identification of Burkholderia cepacia in patients with cystic fibrosis by pulsed-field gel electrophoresis

Background: Complex of Burkholderia cepacia is one of the main and serious causes of infections in cystic fibrosis patients that can be highly transmissible. Small hospital outbreaks are frequent and are usually due to a single contaminated environmental source. The pulsed-field gel electrophoresis (PFGE) is widely used to identify the strain emission sources in cystic fibrosis patients. The aim of this research was to study genotyping of Burkholderia cepacia using PFGE method, and to evaluate diversity complex of clinical strains isolated from cystic fibrosis patients. Methods: This is a descriptive study, in which 100 pulmonary secretion specimens of cystic fibrosis patients admitted in Masih Daneshvari Hospital, Tehran Iran in period of 12 months 2012 to 2013 were collected. The specimens were cultured on BCSA plate’s. After incubation suspected colonies were isolated and identified by biochemical and phenotypic method. All samples were checked by API system (API20NE) and by specific PCR method for genus Bulkhorderia and Bcc as well. DNA was extracted by alkaline lysis method and confirmed by PCR analysis of recA genes. Genetic diversity of isolate was performed by PFGE analysis according to Pulsenet guideline by using XbaI, SpeI as restriction enzyme which digests infrequently among the Burkholderia cepacia genome. Results: Out of 100 samples five were identified as Burkholderia cepacia. It is obviously different at variously reports. The electrophoresis data of PCR products and comparison of band in samples from patients with standard strain ATCC 25416 Burkholderia cepacia and compare and analyse the PFGE size marker bands of Salmonella choleransuis serotype Braenderup H9812 strain, were the same. Conclusion: Application of PFGE and identification of pulse-type is a potential tool to enhance the investigation of apparent nosocomial outbreaks of B.cepacia. Similar type of pulse patterns was observed in this study means that all of infection has been from one source; therefore the hypothesis of transferring person to person will be rejected. Base on these results environmental sources sampling should be considered in future investigation.