Characteristics of Klebsiella isolated from patients in the ICU of a multidisciplinary hospital

Isaenko O.A., Zakharova Yu.V., Shmakova M.A.

Kemerovo State Medical University, Kemerovo, Russia

Aim: to compare bacteriophage resistance, extended-spectrum β-lactamase and invasion enzyme production in hypermucoid and classical K. pneumoniae isolated from ICU patients.
Materials and methods. This is an observational retrospective study with the formation of “case” (hypermucoid phenotype (hmKp), n=27) – “control” (classical phenotype (cKp), n=27) K. pneumoniae pairs. Klebsiella was isolated from biomaterials using a bacteriological method with identification in real-time PCR. Lipase, gelatinase, DNase, and hemolytic activity were studied in Klebsiella. ESBL production was measured using DDST (double disc synergy test), and resistance to 5 commercial bacteriophages was determined using spot tests.
Results. The frequency of hmKp isolation was 11.2 strains per 100 biomaterial samples. The probability of hmKp isolation from wound discharge was 18.5 times higher than cKp (95% CI 3.22-106; p=0.001). Gelatinase was produced by 51.9% of hmKp and 22.2% of cKp (OR=8.62; 95% CI=2.087-35.569; p=0.004). Among hmKp, 77.8% of strains possessed ESBL, among cKp – 85.2% (χ2=0.491; df=1; p=0.484). High resistance of K. pneumoniae to "Intesti-bacteriophage" was established – 96.3% and 88.9%, respectively (χ2=1.08; df =1; p=0.299). Among hmKp ESBL-producing strains resistant to 2 bacteriophages with 1-2 invasion factors were more common (18.5%). Among cKp, the most prevalent(14.8%) phenotype was characterized by production of ESBL, 1-2 invasion factors and resistance to 5 bacteriophages.
Conclusion. The hmKp subpopulation did not differ from cKp in the prevalence of ESBL, but among hmKp, ESBL-producing strains with two invasion factors and resistance to 2 bacteriophages were encountered in 18.5% of cases, while among classical strains, those more often had resistance to 5 bacteriophages.