Detection and Clinical Implications of Biofilm Formation Among Clinical Isolates of Sphingomonas paucimobilis in Turkey

Sphingomonas paucimobilis is a non-fermentative bacillus and found widely in nature. It acquires great interest in biofouling by production of biofilm. However, S. paucimobilis as a biofilm producer, is not studied in medical aspect. In this study we aimed to assess the biofilm production as a virulence factor in clinical isolates of S. paucimobilis together with patient demographics, clinical aspects, risk factors, and outcomes..
During 5 year-period, total numbers of 43 S. paucimobilis isolates identified in a clinical microbiology laboratory of an university hospital in Turkey. Thirty-three of the isolates, which were isolated from patients with clinically determined infection, were enrolled in this study. Patients’ data were collected retrospectively. VITEK II automated system (bioMérieux, Marcy L’Eoile, France) was used for identification and antimicrobial susceptibility testing. Christiansen tube method was used to determine biofilm formation..
All the clinical isolates of S. paucimobilis produced biofilms. Primary bacteraemia (n = 16) was the most common clinical manifestation. Twenty-four of the patients were followed in the intensive care unit. Twenty-two patients had indwelling catheters. Malignancy (n = 11) and diabetes mellitus (n = 10) were the most common concomitant diseases. Tigecycline, carbapenems and aminoglycosides were the most susceptible antimicrobial agents. Degree of biofilm formation was correlated only with blood samples (P = 0.003) in the sample types group and a stay in the intensive care unit (P = 0.002) in the risk factors group..
Sphingomonas paucimobilis can cause serious infections, especially in immunocompromised patients with determined risk factors such as indwelling catheters and diabetes mellitus, due to the effects of multiple virulence factors, together with biofilm formation..