High incidence of type III secretion system associated virulence factors (exoenzymes) in Pseudomonas aeruginosa isolated from Iranian burn patients

Abstract

ObjectiveThe present study aimed to determine the prevalence of virulence factors and antimicrobial resistance profile of Pseudomonas aeruginosa strains isolated from Iranian burn patients.ResultsThis cross-sectional study performed on 100 P. aeruginosa isolates which were recovered from burn wound specimens in 2014–2015. All presumptive isolates were identified by standard microbiologic tests. Antimicrobial susceptibility test was carried out by disk diffusion method. The presence of virulence genes was determined by PCR method. Antibiotic susceptibility results revealed that the isolates were mostly susceptible to amikacin (61%), ceftazidime (60%), and imipenem (55%). Moreover, 59% of the isolates were multi-drug resistance (MDR). The most prevalent MDR pattern was aminoglycosides–penicillins–fluoroquinolones–carbapenems (15%). The presence of exoT, exoY, exoS and exoU genes was detected in 100%, 100%, 59%, and 41% of the tested isolates, respectively. Results points out the pattern of MDR and genetic diversity of type III secretion system among P. aeruginosa strains isolated from the burn population. Overall, the association of MDR and the presence of the specific virulence genes can be a predictive marker for the persistence of these isolates in the hospitals and subsequently a worse clinical condition for the affected patients.

High mortality by nosocomial infections caused by carbapenem-resistant P. aeruginosa in a referral hospital in Brazil: facing the perfect storm

“…According to the literature, relationships between antimicrobial resistance and virulence traits and how they may impact the outcome of bacterial infections are a subject of growing interest [4,16,[25][26][27]. P. aeruginosa is considered one of the most problematic pathogens among Gram-negative bacteria that cause hospital infections, especially due to its extraordinary ability to acquire resistance genes and virulence [25,28].…”

“…In addition to multidrug resistance, studies have shown that the type III secretion system (TTSS), which delivers effector toxins (ExoS, ExoT, ExoY and ExoU) directly into host cells [14,15], is associated with worse clinical outcomes and higher mortality rates in patients infected with P. aeruginosa [16,17]. Aggravating this scenario, some data from epidemiological studies published in the literature suggest that P. aeruginosa strains positive for the exoU gene exhibit higher multidrug resistance and more significant mortality rates than those expressing other TTSS genes [16,18,19].…”

Pseudomonas aeruginosa Type III Secretion System Virulotypes and Their Association with Clinical Features of Cystic Fibrosis Patients

“…ExoS is the major virulence factor associated with invasion, colonization and spread in chronic lung infections and burns. 31 Regardless of the infection status, exoS had a higher prevalence, with only one isolate not harboring such a gene, in addition to a higher frequency than exoU in the evaluated isolates, indicating an important role in lung infection. Feltman et al 16 reported an exoS prevalence of 85% (17/20) in respiratory isolates from CF patients; however, in isolates from other clinical sources, the prevalence varied with statistical significance in relation to isolates from bloodstream infection.…”

“…13,29 Regarding T3SS-related genes, several authors have shown those variations analyzing isolates from distinct setting, including individual, environmental and clinical isolates, demonstrating the important role in the evolution of human disease and persistence in high-pressure settings. 16,17,30,31 In CF P. aeruginosa isolates, the prevalence of these genes is also variable. In a study conducted at an Iranian CF Center evaluating 143 P. aeruginosa isolates, the exoS was the most prevalent (90.2%), followed by exoU (39.8%), in addition to low frequencies of exoT (28.6%) and exoY (25.2%).…”

Active Surgical Treatment Optimization of Severe B

“…The problem of accelerating the regeneration processes in a burn wound, suppressing wound infection, improving the results of autodermoplasty remains unsolved [3]. Despite the fact that in recent years the arsenal of means and methods used for thermal injury has significantly expanded, the results of treatment are not always satisfactory [4]. The costs of treatment of burn patients remain significant, resulting in difficulties with the long stay of patients in the hospital.…”