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Abstract

Nocardia species are ubiquitous in the environment and may be found in the soil. They are generally responsible for sporadic pulmonary diseases acquired by inhalation of spores, with secondary localizations in the central nervous system and subcutaneous tissues. There is no absolute evidence for person to person transmission. Presumptive outbreaks of nocardiosis were observed in immunocompromised patients, more frequently in kidney transplant patients than in cardiac transplant patients. Nocardia spp., being present in dust particles, closure and disinfection of the transplantation unit with formaldehyde arrested the sequence of cases of nocardiosis. The original sources of the Nocardia sp. remain doubtful. Other possible sources of contamination are other patients, medical staff and the hospital environment. The first studies of Nocardia spp. typing were based on the detection of extracellular antigens, on the susceptibility of actinomycete strains to killer yeasts, and on the biochemical profiles with fluorogenic substrate. The use of molecular typing techniques have given very promising results. Analysis of plasmid profiles is an interesting way to compare the identity of isolates, although the reliability of this method depends of the presence of plasmids in the isolates. Other typing methods, including analysis of restriction length fragment polymorphism of total DNA, ribosomal DNA fingerprinting, require further investigations to evaluate their discriminating power or to be easily interpretable, whereas a random amplified polymorphic DNA (RAPD) assay was successful for epidemiological purposes. Progress in epidemiological analysis of cases of nocardiosis will be consistent when an improved diagnosis of this infection (molecular and serological diagnosis) will be available, when the genetic diversity of Nocardia spp. isolates will be better known, and when molecular typing, that hold promise in complementing investigations of outbreak of these infections, will be systematically performed when an abnormal increase of cases of nocardiosis in a population with risk factors is observed.

Genotypic and phenotypic prevalence of Nocardia species in Iran: First systematic review and meta-analysis of data accumulated over years 1992-2021

“…In our study, N. asteroides was the most frequent isolate species, which supports the findings of other research works [3,35]. The pathological importance of Nocardia infections lies on the pathogenesis process in human body.…”

A Diagnostic Challenge: A Case of Disseminated Nocardiosis Presenting With Generalized Lymphadenopathy in a Patient With Interleukin-12 Deficiency

“…The diagnosis of nocardiosis requires a high index of suspicion, and it should be included in the differential diagnosis when the patient presents with features of pulmonary involvement along with brain involvement or multiple distant site involvement, especially with the history of being immunocompromised [ 12 - 14 ].…”

An epidemiological analysis of Nocardia seriolae isolated from a wide range of aquatic animals in Taiwan, based on their genotype and enzymatic activity

“…Information on plasmid carriage also is of special interest because plasmids could be responsible for important phenotypic properties (i.e. specific virulence factors, enzymatic activity and antibiotic resistance) (Provost, Laurent et al, 1996).…”