Genotyping of Pseudomonas aeruginosa Strains Isolated from Surgical Site Infected Patients by RAPD-PCR

Abstract

Marwa Fotouh Mahmoud, Fayza Mahmoud Fathy, Maha Kamal Gohar, Wael Mahmoud Awad, Manar Hassan Soliman

Background: Pseudomonas aeruginosa is one of the most important causes of nosocomial infections that easily gains resistance to many antibiotics. This opportunistic pathogen is a major health hazard particularly in immunocomprmied patients and patients with surgical wound infection. P. aeruginosa may be originated from different sources and comprises a high colonization and transmission capacity. The aim of this study is to determine the antimicrobial susceptibility pattern of the P. aeruginosa isolates and to investigate the potential sources of infection in surgical site infected patients by genotyping using RAPD-PCR.
Methodology: samples were taken from patients (217), health staff (30), environment (88) and antiseptics and hand washing solutions (60). After isolation and identification of P. aeruginosa, antimicrobial susceptibility testing was performed using disc diffusion method. DNA was extracted from the isolates and RAPD-PCR method was applied to the DNA extract using a short single primer of 272. The technique created repetitive electrophoresis patterns which was used for genotypic differentiation.
Results: 24.8% of patient samples were positive for P. aeruginosa and 10% of staff hand samples were positive. The highest frequency of pseudomonas isolation from environmental samples was from mops (55.6%) followed by door handles (44.4%) and sinks (40%). The RAPD typing method gave higher discriminatory index (0.807) than antibiogram (0.617). Epidemiological linkages were proven by analyzing antibiogram and RAPD-PCR typing data.
Conclusion: hand hygiene, environmental cleaning and disinfection of patient objects to reduce environmental reservoirs of P. aeruginosa. It is better to limit the usage of antibiotics in the hospitals as ceftolozane- tazobactam and ceftazidime- avibactam to be used only when absolutely needed. RAPD molecular typing method was superior to antibiotic typing and should be used in tracing the source of infection.