Species Characteristics of Causative Agents of Acute Appendicitis in Children and Determination of Their Susceptibility to Antibiotics

Abstract

In pediatric surgery, acute appendicitis is considered one of the most common problems requiring surgical intervention. Among the causes of this disease, microorganisms are of primary importance. The specificity of postoperative treatment depends both on the degree of virulence of the pathogen and on the microbial load that caused the inflammatory process. The increase in the use of antimicrobial agents is of great concern because of the emergence of antibiotic-resistant bacteria. Therefore, the issue of rational postoperative antibiotic therapy remains relevant, as excessive, often unjustified use and incorrect dosage of drugs have become the cause of many medical problems. The aim of the research was to determine the species structure and analyze antibiotic resistance of microorganisms in biomaterial obtained from children after appendectomy for acute appendicitis. Methods. We studied biomaterial obtained from 74 patients aged 2—18 years who were treated at the MNCE Ternopil Regional Children Clinical Hospital TRC in the period from September 2021 to March 2022. After appendectomy, the samples were placed in a transport medium for further laboratory research, which involved staining smears according to the Gram method, sowing microorganisms on nutrient media such as blood agar, salt agar, sugar broth and serum agar, and Endo medium for enterobacteria as well as for anaerobic pathogens — thioglycolic medium and Kitta-Tarozzi medium, and identifying by morphological, tinctorial, cultural and biochemical properties. The sensitivity of selected pathogenic microorganisms to antibiotics was determined using the Kirby-Bauer method. Statistical processing of digital data was carried out using Excel software (Microsoft, USA) and the Statistica 10.0 program. Results. 74 children aged from 2 to 18 years were involved in the study. E. coli (28.4% of all examined), S. aureus (21.6%), and P. aeruginosa (14.9%) were found during the laboratory study of biomaterial. E. faecalis, Klebsiella spp., S. epidermidis, and S. viridans occurred much less often (from 9.4% to 4.5%). The study of antibiotic resistance showed that the isolated microorganisms differed significantly in their sensitivity both to different groups of antimicrobial agents and to generations of drugs within the same group. Ceftriaxone was the most effective inhibitor of all detected microorganisms. E. coli, S. aureus, P. aeruginosa, and S. epidermidis showed 100% sensitivity to it, and the others — within 75—50%. Bacteria Klebsiella spp. and S. epidermidis were sensitive to amikacin, strains of E. coli — 90.5%, P. aeruginosa and S. aureus — 81.8% and 81.2%, respectively. Amoxiclav and ampisulbin had weak inhibitory activity, except for 100% of Klebsiella spp. and 75% of E. faecalis, which were inhibited only by amoxiclav. However, almost all studied microorganisms were partially sensitive to azithromycin. The activity of this antibiotic ranged from 100—81.8% (S. epidermidis, S. aureus) to 36.4% (P. aeruginosa). Conclusions. The most common causative agents of acute appendicitis among children are the following microorganisms: E. coli, S. aureus, P. aeruginosa, and sporadically — S. saprophiticus, Micrococus spp., S. viridans, and Candida spp. Among the antibiotics used for the treatment of postoperative complications in various forms of appendicitis, the most effective were ceftriaxone — cephalosporins of the III generation — 100—66.7%, amikacin — aminoglycosides — 100—57.1%, and furagin — nitrofuran derivatives — 100—60%. The studied microorganisms were the least sensitive to penicillins and antibiotics of the II generation of the fluoroquinolone group. Resistance of microorganisms to certain antibiotics was also found, in particular: P. aeruginosa and E.  faecalis — to cefuroxime and cefazolin; E. coli and S. aureus — to tobramycin, S. epidermidis — to ofloxacin and amoxiclav.