Forensic Study of Some Immunological and Bacteriological Parameters Among Burned Victims

Forensic Study of Some Immunological and Bacteriological Parameters Among Burned Victims

Summary
Pseudomonas aeruginosa is Gram-negative, facultative an aerobic rods, motile by polar flagellum, non-fermentative, non-sporulating opportunistic pathogens that cause a high rate of mortality and morbidity in hospitalized patients with compromised immune systems. It has the ability to infect almost all tissues of the body as a result of its possession of a large variety of virulence factors that contribute significantly to the pathogenicity of the host, so the rapid detection of these bacteria plays a crucial role in controlling the diseases caused by it, especially in burn injuries.
A total of 100 swab samples were collected from hundred burned patients admitted to three different hospitals in three governorates, The burn unit at Imam Al-Sadiq Hospital (peace be upon him) in Babylon, the burn center at Al-Hussein Teaching Hospital in Kerbala and the burn center in Al-Sadr Medical City in Najaf, during the period from December 2020 to April 2021. These swabs samples was used to investigate the spread of P. aeruginosa and study some virulence factors. In addition to that, 40 blood sample was collected from some of the burned patients in addition to 30 blood sample was collected from apparently healthy individuals. Blood samples was used to investigate the serum level of IL-8 by ELISA.
Swab samples were cultivated on Blood agar, MacConkey agar, and Pseudomonas chromogenic agar. The diagnosis of the isolates was confirmed along with antibiotic sensitivity testing by using the vitek2 compact system. Molecular diagnosis by PCR technology, study of DNA genetic sequence and hypothetical protein structure for P. aeruginosa isolates was done by adopting four genes: lasI, lasR, oprI and oprL.
The results showed that the percentage of burned males was 46%, while the percentage of females was 54%. The highest rate of infection was in children age group 1-10 years (42%), followed by the age group 11-20 with 27%, and the lowest infection rate was in the age group 51-60 and the group above 61 with 1%. There were a high significant difference among age groups (P ≤ 0001).
The results indicated that there was a significant difference (P ≤ 0.002) among the diagnosed cases of injuries in regards to the type of burn, as the highest percentage of burn injuries was from liquid burns by 57%, followed by burns by fire at 41%, and the lowest percentage of injuries was for electric shock burns by 2%. In addition, There were significant difference concerning the degrees of burn rates, Second degree burns were 54% and third degree burns were 45%.
The results of the study showed that the most common bacteria from burn was P. aeruginosa 67.6%, followed by Klebsiella 12.2%, Eschreichia coli 10.8%, Proteus 4%, and the least were Acinetobacter 2.7%, and Citrobacter 2.7%.
The results also showed a high resistance rates of P. aeruginosa to most antibiotics, the highest resistance rates was show against Cefazolin (100%) followed by Tigecycline (96%), Imipenem (86%), Amikacin (86%), Levofloxacin (86%), Gentamicin (84%), Cefepime (74%), Ceftazidime (56%), Ciprofloxacin (4%) while all samples showed high sensitivity (100%) to Piperacillin/Tazobactem.
Regarding molecular technique for P. aeruginosa isolates, the results showed that all isolates were have oprI, oprL genes (100%) and 98% of these isolates have lasI gene and 88% of isolates have lasR gene within the genotype of P. aeruginosa isolates under study.
The alignment sequencing was performed to study the degree of similarity with global strains, compared all DNA sequencing results for P. aeruginosa isolates with the NCBI database, alignment results showed nucleotide sequence ratios similarity with the ratios of the nitrogenous bases stored in the gene bank to a high percentage. The study of the hypothetical protein structure (insilico) showed the presence of gaps at the end of the C-terminal and the transformation of β-sheet proteins due to some genetic changes in the genes of lasI, lasR, oprI and oprL.
The results of the current study showed that the concentration of IL8 in the group of burn patients had a significant increase in the serum level of second and third degree patients (P≤ 0.001( and there was significant increase IL8 level among patients with bacterial infection in comparison to growth negative swabs in the same burn degree at )P≤ 0.05(.
This study concluded that the prevalence of P. aeruginosa is high among clinical samples and it was found that P. aeruginosa isolates are resistant to most antibiotics except Piperacillin/Tazobactem which was sensitive to it (100%). The presence of lasI, lasR and oprI, oprL genes among P. aeruginosa isolates might possibly considered as an alternative methods for diagnosing this bacteria by molecular methods based on PCR and DNA sequencing technology. Moreover, the use of IL-8 as a biomarker for inflammatory processes caused by burns, especially among patients with bacterial infection in the same degree.