• Studying Related to Antimicrobial Resistance Characteristics of Nocardia
  • Sara Safari,1,*
    1. Master of Microbiology, Microbiology, Islamic Azad, Zanjan Branch


  • Introduction: The aerobic, filamentous, branching, gram-positive, slightly acid-fast bacilli known as Nocardia species are widely distributed in the environment. Since inhalation is the primary mode of entry, infection typically presents as pulmonary involvement. Nevertheless, Nocardia species can also spread to numerous organs, with a preference for the central nervous system (CNS), and they can also cause primary cutaneous infections through direct injection. Most people believe that Nocardia species are opportunists that mostly infect immunocompromised persons. Approximately 80% of patients in multiple sizable series from tertiary care facilities had impaired immune systems. Nevertheless, other data have indicated that between 40% and 60% of cases were immunocompetent hosts; the majority of these patients suffer from underlying illnesses such chronic lung disease, diabetes, and alcoholism. Investigating Antimicrobial Resistance Profiles of Nocardia was the goal of this investigation.
  • Methods: The antimicrobial resistance profiles of the nocardia study was conducted by examining academic databases including Pubmed, Google Scholar, Science Direct, and Springer.
  • Results: Understanding antibiotic susceptibility patterns specific to a species is crucial for providing doctors with treatment alternatives. N. asiatica, N. brevicatena/N. paucivorans, N. nova complex, N. transvalensis complex, N. farcinica, N. asteroides, and N. cyriacigeorgica have been identified in the data, in that order. In Brown-Elliott's investigation, the N. transvalensis complex (type IV drug pattern) was imipenem-susceptible, but not in Wallace and McTaggart's studies; in another study, the susceptibility was 50%. The percentage of resistance (52%) among the isolates reported by Uhde was comparable. While McTaggart et al. and others discovered that about half of the isolates were responsive to imipenem and ciprofloxacin, Brown-Elliott et al. and Wallace et al. reported that N. farcinica was susceptible to these medications. N. farcinica showed susceptibilities to these medications of 88% and 60%, respectively, in another investigation. N. otitidiscaviarum isolates (type VII drug pattern) were found by Brown-Elliott et al. to be susceptible to ciprofloxacin; however, the majority of the isolates in the studies by Udhe et al. and McTaggart et al. These findings suggest that the genus Nocardia has complex susceptibility, and further research is needed to understand the traits and processes of this pathogen's antibiotic resistance. It is widely acknowledged that nocardiosis is becoming more common, and that because its clinical signs resemble those of tuberculosis, misdiagnoses may occur. Antituberculotic antibiotics are typically used to treat people who have been misdiagnosed, yet it is unknown how effective these treatments are. thus, examined Nocardia's resistance to seven different classes of traditional antituberculotic drugs. It surprised us to discover that the majority of Nocardia strains, particularly clinical strains, displayed resistance to common antituberculotic drugs. These findings underscore the significance of a prompt and precise diagnosis of Nocardia infections and offer significant information for clinical therapy.
  • Conclusion: The majority of Nocardia isolates are extremely resistant to isoniazid, according to the results, which indicate that SXT, meropenem, imipenem, linezolid, and amikacin are the most effective antimicrobial agents against Nocardia strains. many medication patterns have been found in many species, providing crucial hints for the improvement of Nocardia therapy tailored to a particular species. Therefore, wherever possible, precise taxonomic identification or susceptibility testing of clinical isolates should be carried out before starting treatment. Furthermore, scant information has been documented regarding the genetic foundation of antibiotic resistance in the Nocardia genus (such as alterations in gyrA and gyrB, which encode DNA gyrase and lead to fluoroquinolone resistance, and the presence of genes encoding β-lactamases, which result in β-lactam resistance). Thus, detection procedures should be further evaluated to ensure their reliability, and more work is required to characterize the distribution and properties of antimicrobial resistance-associated genes and mutations in the genus Nocardia.
  • Keywords: Antimicrobial, Nocardia, Β-Lactamases, Antimicrobial