The expanding spectrum of human infections caused by Kocuria species: a case report and literature review

Abstract

Although not previously known to cause human infections, Kocuria species have now emerged as human pathogens, mostly in compromised hosts with severe underlying disease. Recently, there has been an increasing incidence of different types of Kocuria infections reported, most likely due to the adoption of better identification methods. Here, we report a case of peritonitis caused by Kocuria rosea in a diabetic nephropathy patient who was on continuous ambulatory peritoneal dialysis. Sepsis and peritonitis caused by K. rosea in our case yielded two identical Kocuria isolates from the peritoneal dialysate fluid within a period of three days. The infection was subsequently resolved by antibiotic treatment and catheter removal. In addition to reporting this case, we herein review the literature concerning the emergence of Kocuria as a significant human pathogen. The majority of cases were device-related, acquired in the hospital or endogenous, and different Kocuria species appear to share a common etiology of peritonitis. The overall disease burden associated with Kocuria appears to be high, and the treatment guidelines for diseases associated with Kocuria have not yet been clearly defined.

Keywords: CAPD; Kocuria rosea; peritonitis.

Figure 1

(A) Smooth, small, moist, slightly convex, pale-pink colonies of Kocuria observed on sheep blood agar. (B) Smooth, small, pale-cream to pale-pink colonies grown on nutrient agar.

Figure 2

Gram-stain micrograph of Kocuria rosea PKS1409 obtained from a blood agar culture plate showing gram-positive cocci in pairs or clusters observed under oil immersion (×100).

Figure 3

Phylogenetic analysis using MEGA V-5.1 based on the 16S rRNA gene sequences of all the representative Kocuria species, along with strain K. rosea PKS1409 obtained in this study. Bar=0.005 nucleotide substitutions per position.