Epidemiology of Nocardia Species at a Tertiary Hospital in Southern Taiwan, 2012 to 2020: MLSA Phylogeny and Antimicrobial Susceptibility

Abstract

The identification and antimicrobial susceptibility of Nocardia spp. are essential for guiding antibiotic treatment. We investigated the species distribution and evaluated the antimicrobial susceptibility of Nocardia species collected in southern Taiwan from 2012 to 2020. A total of 77 Nocardia isolates were collected and identified to the species level using multi-locus sequence analysis (MLSA). The susceptibilities to 15 antibiotics for Nocardia isolates were determined by the broth microdilution method, and the MIC50 and MIC90 for each antibiotic against different species were analyzed. N. cyriacigeorgica was the leading isolate, accounting for 32.5% of all Nocardia isolates, and the prevalence of Nocardia isolates decreased in summer. All of the isolates were susceptible to trimethoprim/sulfamethoxazole, amikacin, and linezolid, whereas 90.9% were non-susceptible to cefepime and imipenem. The phylogenic tree by MLSA showed that the similarity between N. beijingensis and N. asiatica was as high as 99%, 73% between N. niigatensis and N. crassostreae, and 86% between N. cerradoensis and N. cyriacigeorgica. While trimethoprim/sulfamethoxazole, amikacin, and linezolid remained fully active against all of the Nocardia isolates tested, 90.9% of the isolates were non-susceptible to cefepime and imipenem.

Development of a recombinase-aided amplification assay for rapid detection of the human pathogen Nocardia farcinca

“…N. farcinica is a human pathogen that usually spreads from lung infection to different organs of the body, with potentially fatal consequences [22]. Currently, sequence analysis of the 16S rRNA gene is considered the "gold standard" for the identi cation of Nocardia isolates, which major drawbacks are a limited su cient resolution at the species level and low value for early diagnosis [23].…”

Nodular Cutaneous Lesions in Immune-Compromised Hosts as a Clue for the Diagnosis of Disseminated Nocardiosis: From Bedside to Microbiological Identification

“…This is the reason why the diagnosis of nocardiosis depends on a close collaboration among physicians and clinical microbiologists. Moreover, Nocardia microbiological identification at the species-level is mandatory to interpret clinically significant isolates and to administer correct antimicrobial therapy since Nocardia drug resistance patterns are largely species-related [ 28 , 29 , 30 , 31 ]. For this purpose, because of the shortcomings of the commercial MALDI-TOF MS database for the identification of Nocardia species, further identification based on the complete sequence of the gold standard 16S rRNA is recommended to confirm species assignment [ 32 ].…”

“…For this purpose, because of the shortcomings of the commercial MALDI-TOF MS database for the identification of Nocardia species, further identification based on the complete sequence of the gold standard 16S rRNA is recommended to confirm species assignment [ 32 ]. In fact, N. farcinica together with the N. transvalensis complex, N. otitidiscaviarum and the N. nova complex N. farcinica is one of the multidrug-resistant (MDR) species reported in the literature [ 29 , 30 , 31 ]. Not all studies, however, agree on resistance percentages.…”