Clinical significance, antimicrobial susceptibility and molecular identification of Nocardia species isolated from children with cystic fibrosis

Abstract

Nocardia is an opportunistic pathogen that causes respiratory infections in immunocompromised patients. The aim of this study was to analyze the epidemiology, clinical significance and antimicrobial susceptibility of Nocardia species isolated from eight children with cystic fibrosis. The isolated species were identified as Nocardia farcinica, Nocardia transvalensis, Nocardia pneumoniae, Nocardia veterana and Nocardia wallacei. N. farcinica was isolated in three patients and all of them presented lung affectation with a chronic colonization and pneumonia. N. farcinica showed resistance against gentamicin, tobramycin, cefotaxime, but was susceptible to trimethoprim-sulfamethoxazole and amikacin. N. transvalensis, which was isolated from two patients, showed an association with chronic colonization. N. transvalensis was resistant to tobramycin and amikacin, but susceptible to ciprofloxacin, trimethoprim-sulfamethoxazole and cefotaxime. N. veterana, N. pneumoniae and N. wallacei were isolated from three different patients and appeared in transitory lung colonization. N. veterana and N. pneumoniae were susceptible to imipenem, trimethoprim-sulfamethoxazole, amikacin, tobramycin, and cefotaxime. N. wallacei was resistant to amikacin, tobramycin, imipenem, and trimethoprim-sulfamethoxazole and susceptible to ciprofloxacin and cefotaxime. All the isolates were identified up to species level by 16S rRNA gene sequencing. The presence of Nocardia in the sputum of patients with cystic fibrosis is not always an indication of an active infection; therefore, the need for a treatment should be evaluated on an individual basis. The detection of multidrug-resistant species needs molecular identification and susceptibility testing, and should be performed for all Nocardia infections.

High Intraspecific Genetic Diversity ofNocardia brasiliensis, a Pathogen Responsible for Cutaneous Nocardiosis Found in France: Phylogenetic Relationships by Usingsodandhsp65Genes

“…In addition to the phenotype-based methods, species-level identification is mainly genetically based, nowadays. Classically, 16S rRNA (rrs) gene sequencing is generally used for the species-level identification [ 7 , 8 ], but it fails to discriminate among some species of Nocardia because it does not have enough polymorphism to differentiate them at the species level. Multilocus sequence analysis (MLSA) using concatenated sequences of several housekeeping genes such as superoxide dismutase A (sodA) and heat shock protein 65 (hsp65) has been increasingly used to provide higher accuracy and discriminatory power in the molecular identification of Nocardia spp.…”

Successful Treatment of Disseminated Nocardiosis Caused by Nocardia veterana in a Dog

“…12 Since it was first isolated, fewer than 20 cases of N. veterana infection have been reported in the human literature. 5,7,[13][14][15][16][17][18] Inhalation is thought to be the most common route of transmission, and in the few reported cases of human N. veterana infections, pulmonary manifestations predominate. 6,7,13 However, a wide variety of other clinical manifestations of N. veterana infection have been reported in humans including urinary tract infections, brain and bowel abscesses, endogenous endophthalmitis, nodular lymphangitis, mycetomas, and bacteremia.…”

“…5,7,[13][14][15][16][17][18] Inhalation is thought to be the most common route of transmission, and in the few reported cases of human N. veterana infections, pulmonary manifestations predominate. 6,7,13 However, a wide variety of other clinical manifestations of N. veterana infection have been reported in humans including urinary tract infections, brain and bowel abscesses, endogenous endophthalmitis, nodular lymphangitis, mycetomas, and bacteremia. 5,[14][15][16][17][18][19] In veterinary medicine, reports of N. veterana infection have been limited to bovine mastitis resulting from direct inoculation, and a puppy from Germany with disseminated N. veterana infection and concurrent canine distemper virus infection.…”

Macrophage activation syndrome due to Nocardia spp in a pediatric patient with cystic fibrosis

“…Nocardia spp is a gram‐positive aerobic filamentous bacteria that is ubiquitous in soil and aquatic habitats . It may cause disseminated infection, most commonly involving the lungs, subcutaneous tissues, central nervous system, and rarely other organs such as heart .…”

“…It may cause disseminated infection, most commonly involving the lungs, subcutaneous tissues, central nervous system, and rarely other organs such as heart . It is known that it can be detected in healthy individuals, but patients who have cell‐mediated immunodeficiency such as HIV infection, neoplastic disease, and transplant recipients, as well as patients who are treated with corticosteroids or immunosuppressive drugs or have chronic lung diseases such as bronchiectasis, asthma, mycobacterial infection, tuberculosis, and chronic granulomatosis disease have higher risk . It is a known pathogen in adult CF patients; however, it has increasingly been reported in pediatric CF patients in recent years …”