Fatal hemorrhagic pneumonia caused by infection due to Kytococcus sedentarius--a pathogen or passenger?

Case Report of Infectious Spondylitis Caused by Kytococcus sedentarius

Background: Kytococcus species has not been considered a pathogen, but infections caused by this species are increasing. There are several cases of infections caused by Kytococcus sedentarius, but no case of infectious spondylitis has been reported yet. Case presentation: A 79-year-old female patient was hospitalized because of back pain for several months. She was diagnosed with infectious spondylitis, and K. sedentarius was cultured from the pus and specimen obtained during the surgical procedure. The patient recovered completely without recurrence after 6 months of treatment with ciprofloxacin alone for 8 weeks. Conclusion: This is the first case report of infectious spondylitis caused by K. sedentarius.

Unusual source of recurrent Corynebacterium bacteraemia in an immunocompromised patient

We describe a unique case of a patient with acute myeloid leukaemia (AML), with recurring infections during chemotherapy from chronic nasal carriage of non-diphtherial Corynebacterium, who was eventually diagnosed as she presented with neutropaenic sepsis. Identifying (often multiple) sources of infection in immunocompromised patients is crucial but deciding whether multiple organisms, which in health are considered as commensals, are actually pathogenic during vulnerable states—can be clinically difficult. Our case highlights the efforts to correctly identify the actual source of this rare organism and the recognition of its pathogenic potential when other illnesses present. We also review the literature of Corynebacteria in patients with haematological malignancies but believe this is the first case of AML to be infected with Corynebacterium presenting during the COVID-19 pandemic with a probable incidental positive swab for SARS-CoV-2.

Analysis of Kytococcus sedentarius Strain Isolated from a Dehumidifier Operating in a University Lecture Theatre: Systems for Aerobic Respiration, Resisting Osmotic Stress, and Sensing Nitric Oxide

A strain of Kytococcus sedentarius was isolated from a dehumidifier operating in a university lecture theatre. Genome analysis and phenotypic characterisation showed that this strain, K. sedentarius MBB13, was a moderately halotolerant aerobe with a branched aerobic electron transport chain and genes that could contribute to erythromycin resistance. The major compatible solute was glycine betaine, with ectoine and proline being deployed at higher osmolarities. Actinobacteria possess multiple WhiB-like (Wbl) regulatory proteins, and K. sedentarius MBB13 has four (WhiB1, WhiB2, WhiB3, and WhiB7). Wbls are iron-sulfur proteins that regulate gene expression through interactions with RNA polymerase sigma factors and/or other regulatory proteins. Bacterial two-hybrid analyses suggested that WhiB1 and WhiB2, but not WhiB3 and WhiB7, interact with the C-terminal domain of the major sigma factor, σA; no interaction was detected between any of the Wbl proteins and the only alternative sigma factors, σB, σH, or σJ. The interaction between σA and WhiB1 or WhiB2 was disrupted in a heterologous system under growth conditions that produce nitric oxide and the iron-sulfur clusters of the isolated WhiB1 and WhiB2 proteins reacted with nitric oxide. Thus, K. sedentarius strain exhibits the major phenotypic characteristics of the type strain and a comprehensive examination of the interactions between its four Wbl proteins and four sigma factors suggested that the Wbl proteins all operate through interaction with σA.

Bioburden in sleeping environments from Portuguese dwellings

A wider characterization of indoor air quality during sleep is still lacking in the literature. This study intends to assess bioburden before and after sleeping periods in Portuguese dwellings through active methods (air sampling) coupled with passive methods, such as electrostatic dust cloths (EDC); and investigate associations between before and after sleeping and bioburden. In addition, and driven by the lack of information regarding fungi azole-resistance in Portuguese dwellings, a screening with supplemented media was also performed. The most prevalent genera of airborne bacteria identified in the indoor air of the bedrooms were Micrococcus (41%), Staphylococcus (15%) and Neisseria (9%). The major indoor bacterial species isolated in all ten studied bedrooms were Micrococcus luteus (30%), Staphylococcus aureus (13%) and Micrococcus varians (11%). Our results highlight that our bodies are the source of the majority of the bacteria found in the indoor air of our homes. Regarding air fungal contamination, Chrysosporium spp. presented the highest prevalence both in after the sleeping period (40.8%) and before the sleeping period (28.8%) followed by Penicillium spp. (23.47% morning; 23.6% night) and Chrysonilia spp. (12.4% morning; 20.3% night). Several Aspergillus sections were identified in air and EDC samples. However, none of the fungal species/strains (Aspergillus sections Fumigati, Flavi, Nidulantes and Circumdati) were amplified by qPCR in the analyzed EDC. The correlations observed suggest reduced susceptibility to antifungal drugs of some fungal species found in sleeping environments. Toxigenic fungal species and indicators of harmful fungal contamination were observed in sleeping environments.

Vascular Homograft Use in a Femoropopliteal Rare Bacterial Infection Bypass

We report on a patient with a femoropopliteal bypass infected by Kytococcus sedentarius. Treatment consisted of resection of the infected prosthesis with homograft substitution and antibiotic therapy started postoperatively At 6 months followup, the patient showed no signs of infection and results of laboratory findings were normal.

Kytococcus schroeteri pneumonia in two patients with a hematological malignancy

Neutropenic patients are susceptible to infections with usually harmless microorganisms. We report two cases of severe pneumonia in hematological patients due to Kytococcus schroeteri, a saprophyte of the human skin. When blood cultures or respiratory specimens yield micrococcus-like colonies, Kytococcus species, which are often resistant to penicillin, should be considered and the antimicrobial therapy should be adjusted accordingly.

Complete genome sequence of Kytococcus sedentarius type strain (541)

Kytococcus sedentarius (ZoBell and Upham 1944) Stackebrandt et al. 1995 is the type strain of the species, and is of phylogenetic interest because of its location in the Dermacoccaceae, a poorly studied family within the actinobacterial suborder Micrococcineae. Kytococcus sedentarius is known for the production of oligoketide antibiotics as well as for its role as an opportunistic pathogen causing valve endocarditis, hemorrhagic pneumonia, and pitted keratolysis. It is strictly aerobic and can only grow when several amino acids are provided in the medium. The strain described in this report is a free-living, nonmotile, Gram-positive bacterium, originally isolated from a marine environment. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first complete genome sequence of a member of the family Dermacoccaceae and the 2,785,024 bp long single replicon genome with its 2639 protein-coding and 64 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.

Kytococcus schroeteri infection of a ventriculoperitoneal shunt in a child

Kytococcus schroeteri is a newly described micrococcal species and, to date, has been associated mostly with endocarditis. Six infections attributable to this opportunistic pathogen have been described since 2002, when the first case was identified. We describe here the first pediatric case of a K. schroeteri ventriculoperitoneal shunt infection. The child was successfully treated with a combination of rifampin and vancomycin and shunt replacement. Initially identified as a Micrococcus spp. by both automated identification and conventional biochemical testing, sequencing of the 16S ribosomal RNA gene enabled accurate identification of the organism.

Kocuria rhizophila adds to the emerging spectrum of micrococcal species involved in human infections

We describe the first case of a Kocuria rhizophila infection in a boy with methylmalonic aciduria. A single clone was isolated from blood samples drawn through a port system and from peripheral veins during septic episodes within a 2-year period. K. rhizophila expands the emerging number of "micrococci" considered to be etiologically relevant.