Clinical Nocardia species: Identification, clinical characteristics, and antimicrobial susceptibility in Shandong, China

Abstract

Nocardia is a pathogen responsible for a variety of clinical infections. Here, we aimed to investigate the species distribution, clinical manifestations, and antimicrobial susceptibility of Nocardia species in two tertiary general hospitals over 3 years in China. In this retrospective study, a total of 27 Nocardia species were isolated from 27 individuals between January 2017 and December 2019. Nocardia isolates were identified to species level by mass spectrometry and 16S rRNA PCR sequencing. Clinical data were collected from medical records. Antimicrobial susceptibility was determined by standard Broth microdilution method. The 27 patients with Nocardia infection included 12 males and 15 females with a mean age of 60.11 years. Among 27 Nocardia isolates, 7 species were identified, with the most common species being N. otitidiscaviarum (40.7%). The antimicrobial susceptibility profiles varied between different Nocardia species. Notably, all Nocardia isolates were linezolid susceptible. Majority of Nocardia isolates were collected from a department of respiratory medicine (55.56%) and sputum specimen (44.44%). Pulmonary region was the most involved body site (70.37%), followed by skin (7.4%) and pleural cavity (7.4%). Most patients with Nocardia infection needed combination antibiotic therapy. Two deaths were reported during the treatment period and 24 patients achieved improvement after antibiotic therapy. The clinical manifestations of Nocardia infection and antimicrobial susceptibility profiles varied with diverse Nocardia species. Thus, the accurate identification of these species is crucial for the diagnosis and the selection of antibiotic treatment.

MLSA phylogeny and antimicrobial susceptibility of clinical Nocardia isolates: a multicenter retrospective study in China

“…Overall, 98.8% of isolates were susceptible to SXT, and only one isolate of N. wallacei was resistant to the drug (Table 1 ). Similar results are reported by Lu et al and other researchers [ 20 , 36 – 39 ]. Therefore, the present study indicates that SXT remains high-level of activity against Nocardia in vivo and can still be considered as the first-line therapeutic drug of choice for nocardiosis in China.…”

“…Based on the current study and the related references mentioned above [ 20 , 32 ], an interesting phenomenon was found: Some species prefer to be distributed according to the climate type, while others prefer to be distributed along the coast in China. Shanxi, Hebei, Beijing, and Shandong all belong to the monsoon climate of medium latitudes, and N. abscessus is prevalent.…”

“…Even within China, the prevalent species also have regional characteristics. N. otitidiscaviarum appears to be more prevalent in the eastern and southern coastal areas of China, and N. abscessus prefers to be distributed in the neighboring northern provinces of China, including Shanxi, Hebei, Beijing, and Shandong [ 20 , 32 ]. N. aobensis and N. nova which are close species on 16S rRNA and/or secA1 genes and even classified into N. nova complex by Conville et al [ 4 ], are distributed in Jiangsu in this study, while N. nova is distributed in Shandong in the study by Huang et al [ 32 ] Actually, Jiangsu and Shandong are adjacent to each other.…”

“…There are few large-scale studies [ 20 , 21 ] about the antimicrobial susceptibility pattern of various Nocardia species based on BMD method that is recommended by the CLSI [ 18 ] in China. This study provides a relatively large collection of clinical Nocardia isolates to explore the correlation between antibiotics and species and reach a guideline for the nocardiosis treatment in China.…”

“…According to the reports [ 28 , 31 ], the isolation rates of N. nova complex and N. farcinica which have high resistance rates to SXT were more than 10% in Spain and the USA. However, the former is rarely isolated in China [ 20 , 32 ], and the latter may be divided into different types due to the different geographic areas.…”