The Virulence Genes of Sensitive Strain Pseudomonas aeruginosa Causing Nosocomial Outbreaks

Abstract

Pseudomonas aeruginosa is an opportunistic pathogen which is commonly associated with healthcare associated infection. They possess multiple pathogenic factors which play a role in causing invasive infections such as surgical site infection, pneumonia, and blood stream infection. There were two hospital outbreaks caused by sensitive strains P. aeruginosa between 2016 and 2017 involving 17 patients. The outbreak investigation by Pulsed Field Gel Electrophoresis (PFGE) revealed seven clonally related P. aeruginosa strains (A-G). This study aims to determine the virulence factors acquired by the P. aeruginosa isolates and describe the clinical outcome of the patients. Seventeen P. aeruginosa isolates from the stocked collection were retrieved for six virulence genes, namely ToxA, ExoS, LasI, LasB, OprI, and OprL by PCR. Ten out of 17 of the P. aeruginosa isolates were able to revive. The ExoS, LasI, LasB, OprI, and OprL genes, respectively, were detected in all isolates, while ToxA gene was detected in six isolates which belonged to clone A (one isolate) and clone C (five isolates). The isolate from clone A caused pneumonia and isolates from clone C caused surgical site infections which led to disseminated infections and death. The presence of multiple virulence genes in these P. aeruginosa isolates may have contributed to the invasiveness, and the outcome of the infection. More studies with a larger number of patients will give a better insight regarding the actual role of these genes in different clinical manifestations caused by sensitive strain P. aeruginosa.