Hospitalization length survey and relation with distribution of LasA protease and type III secretion system encoding-genes in multi-drug resistant Pseudomonas aeruginosa isolates from burn wounds in southwest of Iran

Virulence factors are the main reason of bacterial pathogenicity. Pseudomonas aeruginosa is an opportunistic bacterium which has been armed with many virulence factors involved in its acute infection ability. Some of these importance factors have been involved in tissue destruction are proteases like elastase and exoenzymes. According to the importance of elastase activity in preventing wound healing and the activity of type III secretion system (T3SS) in injection secreted proteins to the host cells, we aimed that virulence factors pattern in Pseudomonas aeruginosa isolates from burn wounds may change the length of burn patients hospitalization time. Therefore, Pseudomonas aeruginosa isolates from Burn wounds were evaluated for presence of elastase activity and T3SS and their relation to the hospitalization length of patients In this cross sectional study (January 2015-January 2016) total of 38 Pseudomonas aeruginosa isolates were collected from burn wounds (one isolate from one patient) hospitalized in Amir-Al-Momenin burn hospital affiliated with Shiraz University of Medical Sciences, Shiraz, Iran. Isolates were detected and confirmed with specific bacteriology standard methods. All of the isolates were evaluated for antimicrobial sensitivity pattern, and presence of LasA and PcrH genes related to Elastase activity and T3SS respectively. The presence of these genes and hospitalization time of patients were compared with chi-square analytical analysis (SPSS software, V.18). The prevalence of Pseudomonas aeruginosa was 15.2% at the time of study, where > 85% of them were detected multidrug resistant. Separate results for LasA and PcrH presentation was 73.7% and 76.3% respectively, while about 63% of isolates harbor both genes simultaneously and this group of patients have more length of stay in hospital (P value ≤ 0.003). According to the results we concluded that presenting of several factors by a circulating infectious agents simultaneously make the situations of infected patients more critical. Either we highly recommended that the clinical centers such as burn clinics prioritize the determining of the sensitivity pattern of their prevalent infections. Knowing these algorithms will help patients to be treated faster and decrease all of the related costs.