Kocuria varians meningitis in a child with chronic granulomatous disease

Kocuria species: an underappreciated pathogen in pediatric patients-a single-center retrospective analysis of 10 years' experience in China

Kocuria species are known to be opportunistic pathogens that cause infections in humans, especially immunocompromised hosts. However, reports of pediatric patients are limited. This retrospective study was designed to investigate the spectrum of infections in pediatric patients caused by Kocuria species. Thirty-six patients were enrolled; of these, 29 were infected by Kocuria kristinae, 4 by Kocuria roseus, 2 by Kocuria varians, and 1 by Kocruria rhizophila. Twenty-six patients were diagnosed with bloodstream infection; 6 had ventilator-associated pneumonia; and one each had a catheter-associated urinary tract infection, purulent meningitis, cholangitis, and empyema. Twenty-seven patients were immunocompromised or debilitating, had congenital abnormalities or fitted with indwelling devices. Nine patients were immunocompetent, 4 with early onset before 1 year of age. All Kocuria species were susceptible to lenezolid, vancomycin, and tigecycline; while showing frequent resistance to penicillin and oxacillin. Most cases were cured by administering appropriate antimicrobial agents. To our knowledge, this is the largest case series of pediatric patients with Kocuria species infection. We highlight Kocuria species should be considered as an underappreciated pathogen in pediatric patients.

Kocuria Species Infections in Humans-A Narrative Review

Kocuria species are catalase-positive and coagulase-negative Gram-positive coccoid bacteria that belong to the family Micrococcaceae, order Actinomycetales, and class Actinobacteria. Even though they may be relatively rare, they have been increasingly reported as the causes of human infections lately. The present study aims to review all published cases of Kocuria spp. infections in humans reporting data on epidemiology, microbiology, antimicrobial susceptibility, antimicrobial treatment, and mortality. A narrative review was performed based on a search of Pubmed and Scopus databases in the literature. In total, 73 studies provided data on 102 patients with Kocuria spp. infections. The mean age of patients was 47 years, and 68.3% were male. The most common types of infection were bacteremia (36.3%), skin and soft tissue infection (18.6%), endophthalmitis (15.7%), infective endocarditis (13.7%), and peritonitis (11.8%), most commonly peritoneal-dialysis-associated. The most frequently isolated species was K. kristinae (46.1%), and antimicrobial resistance was lower for vancomycin (7%) and tetracyclines (6.7%). Vancomycin (47%), cephalosporins (39.6%), and quinolones (36.6%) were the most commonly used antimicrobials. The empirical antimicrobial treatment of Kocuria spp. infections should include vancomycin as long as antimicrobial susceptibility results are pending. The infection outcome mainly depends on the type of infection and is higher for infective endocarditis. Endophthalmitis is associated with increased rates of low visual acuity after treatment.

A new pathogenic isolate of Kocuria kristinae identified for the first time in the marine fish Larimichthys crocea

In recent years, new emerging pathogenic microorganisms have frequently appeared in animals, including marine fish, possibly due to climate change, anthropogenic activities, and even cross-species transmission of pathogenic microorganisms among animals or between animals and humans, which poses a serious issue for preventive medicine. In this study, a bacterium was clearly characterized among 64 isolates from the gills of diseased large yellow croaker Larimichthys crocea that were raised in marine aquaculture. This strain was identified as K. kristinae by biochemical tests with a VITEK 2.0 analysis system and 16S rRNA sequencing and named K. kristinae_LC. The potential genes that might encode virulence-factors were widely screened through sequence analysis of the whole genome of K. kristinae_LC. Many genes involved in the two-component system and drug-resistance were also annotated. In addition, 104 unique genes in K. kristinae_LC were identified by pan genome analysis with the genomes of this strain from five different origins (woodpecker, medical resource, environment, and marine sponge reef) and the analysis results demonstrated that their predicted functions might be associated with adaptation to living conditions such as higher salinity, complex marine biomes, and low temperature. A significant difference in genomic organization was found among the K. kristinae strains that might be related to their hosts living in different environments. The animal regression test for this new bacterial isolate was carried out using L. crocea, and the results showed that this bacterium could cause the death of L. crocea and that the fish mortality was dose-dependent within 5 days post infection, indicating the pathogenicity of K. kristinae_LC to marine fish. Since K. kristinae has been reported as a pathogen for humans and bovines, in our study, we revealed a new isolate of K. kristinae_LC from marine fish for the first time, suggesting the potentiality of cross-species transmission among animals or from marine animals to humans, from which we would gain insight to help in future public prevention strategies for new emerging pathogens.