Pluralibacter gergoviae
Pluralibacter gergoviae is a Gram-negative, motile, facultatively-anaerobic, rod-shaped bacterium. P. gergoviae is of special interest to the cosmetics industry, as it displays resistance to parabens, a common antimicrobial agent added to cosmetic products.
It is typically an opportunistic human pathogen, primarily affecting immunocompromised patients.
Background
Enterobacter gergoviae was first proposed as a novel species in 1980. The species name is derived from the Gergovie plateau, which is located near Clermont-Ferrand University Hospital; the type strain was isolated at this hospital during a nosocomial outbreak of P. gergoviae. In 2013, the species was reclassified into the novel genus, Pluralibacter, and is the type species for the genus.Pluralibacter gergoviae has been isolated from maize, grapes, coffee beans, spring water, fruit flies, and pink bollworms.
Microbiology
Pluralibacter gergoviae is a Gram negative, non-spore forming, motile, facultatively anaerobic bacillus. It is non-hemolytic and grows at mesophilic temperatures, from 10 - 41°C, with optimum growth at 30 - 37°C. It can produce urease and acetoin, and is hydrogen sulfide, cytochrome-c oxidase, and indole negative. Additionally, it does not ferment inositol, d-sorbitol, and mucate, which distinguishes it from Klebsiella aerogenes ''.Pluralibacter gergoviae can be grown on trypticase soy agar and Columbia blood agar. However, it does not grow in potassium cyanide broth. Colonies are typically unpigmented, round, and smooth on tryptic soy agar.
Medical Relevance
Pluralibacter gergoviae is an uncommon human pathogen and is most commonly an opportunistic nosocomial infection. One hospital in Spain reported the organism to represent 0.4% of clinical Enterobacter isolates. Risk factors include prolonged hospital stays, immunosuppression, the presence of a foreign device, prior use of anti-microbial agents in the patient involved, and extremes of age. In the cosmetic industry, P. gergoviae has been implicated in recalls of eye cream, children's shampoo, skin cream, hand cleaning paste, and cleansing wipes.Infections caused by this organism are most frequent in transplant recipients, patients with hematologic malignancies, and in neonatal outbreak settings. Additionally, there has been a report of hyperammonemia syndrome in an immunocompromised lung transplant patient due to P. gergoviae, believed to be triggered by urease production.
When P. gergoviae infection becomes established, it can be difficult to treat due to its intrinsic resistance to many antibiotics. It is resistant to penicillins, macrolides, lincosamides, streptogramins, rifampicin, fusidic acid, and fosfomycin. P. gergoviae is also resistant to cefoxitin, likely due to β-lactamase production. In a systematic review of case studies, it was found that 33% of the isolates were multi drug resistant, and all fatal cases involved isolates carrying the blaKPC gene.