Pulmonary Nocardiosis in Pemphigus Vulgaris Patients from Tehran, Iran

Abstract

Objective: Nocardiosis is an opportunistic infection in individuals who had organ transplants and in patients with immunosuppressive diseases, such as pemphigus vulgaris (PV), diabetes mellitus, and HIV. Nocardiosis rate has not been assessed in Iranian PV patients, and this was the first study to estimate nocardiosis rate in these patients. : In this study, 103 PV patients have been studied. BAL samples were obtained and direct smear was analyzed by PAS staining. Samples were cultured on antibiotic containing blood and chocolate agar media. DNA extraction and PCR were performed on positive cultures, and final identification was done by 16S rRNA gene sequencing. Drug susceptibility testing was done by micro-broth dilution method. Results: Four positive cultures (3.88%) were found in the samples (n = 103). According to sequence analysis, 2 isolates were identified as N. cyriacigeorgica and 2 as N. otitidiscaviarum and N. cerradoensis. N. cerradoensis isolated from an invasive brain infection. Isolated bacteria were susceptible to majority of the tested antibiotics, except 1 isolate of N. cyriacigeorgica and isolate of N. cerradoensis. This was the first isolation of N. cerradoensis of human infection in Asia. PV patients are as susceptible to nocardiosis as other immunocompromised patients.

Detection of Nocardia by 16S Ribosomal RNA Gene PCR and Metagenomic Next-Generation Sequencing (mNGS)

“…However, early application of suitable antibiotherapy, which depends on early detection of the nocardial infection, is vital for decreasing the high death rates of patients with nocardiosis (Couble et al, 2005). 16S rRNA PCR and sequencing offer accurate, inexpensive, rapid, and reliable identification of nocardial infection among species (Rahdar et al, 2021). At present, 16S rRNA PCR and sequencing are used for limited number of pathogens at a time or successful culture of microorganisms from clinical samples was required.…”

Pathogenic Nocardia amamiensis infection: A rare case report and literature review

“…According to the Clinical and Laboratory Standards Institute (CLSI) guidelines, the broth microdilution method is recommended for determining the Minimum Inhibitory Concentration (MIC) and conducting antibiotic susceptibility testing (AST) for Nocardia . Alternative methods such as Resazurin, Spectrophotometric readings, and microplate Alamar Blue assays have also shown high agreement rates with the broth microdilution method [ [28] , [29] , [30] ].…”