Infection with klebsiella and pseudomonas in mine-blast wounds: frequency of their isolation at the third stage of evacuation; spectrum of their resistance; sensitivity to antimicrobial drugs; general rules of military medical care

Abstract

Introduction. During the war that has been going on in Ukraine for two years, the number of patients with mine-blast injuries has increased dramatically. The issue of wound colonization by resistant microorganisms and modification of their species spectrum, which increases during the evacuation of victims to various medical facilities, is of great importance. At the third stage of wounded military personnel evacuation 87.7 % of wounds were occupied by gram-negative bacteria in the form of monoculture, including strains of Pseudomonas aeruginosa and Klebsiella pneumoniae with multidrug resistance, which have a high potential for adaptation in hospital conditions. The aim of the study. To investigate the frequency of infection with Klebsiella and Pseudomonas of mine-blast wounds at the third stage of evacuation, to determine the spectrum of their resistance, sensitivity to antimicrobial drugs, and to present general recommendations for military medical care. Materials and methods. The material from purulent wounds was taken from victims with mine-blast injuries who were admitted for inpatient treatment to the surgical department. The sampling was carried out with sterile swabs with transport nutrient medium. The material was inoculated on blood agar, Endo medium, CHROMID® P. Aeruginosa Agar, MPA and incubated at 37°C for 24 hours. Biochemical identification was performed using the Enterotest 24 and Nefermtest 24 test systems (Lachema, Czech Republic). Antimicrobial susceptibility testing was performed using the Kirby-Bauer method and the determination of the minimum inhibitory concentration (MIC) using broth microdilutions according to the recommendations of the European Committee for the Antimicrobial Susceptibility Testing (EUCAST 2023). Healthcare-associated infections (HCAI) among the wounded servicemen were diagnosed according to the updated MoH Order No. 1447. Results. K. pneumoniae and P. aeruginosa were isolated from the wounds of 38 examined mine-blast injured patients. Out of these 17 (44.7 %) patients had P. aeruginosa; in 9 patients both pathogens were in association; in 2 patients P. aeruginosa was isolated in pure culture; in the remaining cases P. aeruginosa was in association with other microorganisms. Quantitatively, the bacteria were isolated in the range of 106-109 colony forming units (CFU/ml) of pathogen in the patient’s wound contents. In wounded servicemen, infectious wound complications appeared later than the 3-rd day of hospital stay, so they were classified as HCAI. 33.3 % and 22.2 % of K. pneumoniae isolates demonstrated susceptibility to amikacin and imipenem, respectively. Moderate susceptibility of P. aeruginosa to amikacin was detected in 29.4 % of isolates, and to ticarcillin-clavulanate – in 23.5 %. 41.2 % of P. aeruginosa isolates demonstrated sensitivity to piperacillin-tazobactam, 23.5 % – to imipenem, and 11.8 % – to ceftazidime. No significant difference was detected between the susceptibility of Pseudomonas and Klebsiella strains to imipenem (p more than 0.05). It was recorded absolute susceptibility of K. pneumoniae and P. aeruginosa strains to colistin. In total 92.3 % of P. aeruginosa and 90.7 % of Klebsiella isolates were represented by multidrug-resistant strains. Timely and thorough primary surgical treatment of the wound and correct antimicrobial treatment reduce the risk of wound infection. Conclusions. K. pneumoniae and P. aeruginosa were isolated from 44.7 % of wounded servicemen with mine-blast trauma at the third stage of evacuation. There was an increase in the frequency of multidrug-resistant strains of K. pneumoniae (90.7 %) and P. aeruginosa (92.3 %). The isolated strains of K. pneumoniae and P. aeruginosa that induced healthcare-associated infections were hospital-acquired. All isolates were susceptible to colistin. High-quality treatment of wound requires complete elimination of microorganisms prior to further rehabilitation stages.