<p>Species Diversity, Molecular Characterization, and Antimicrobial Susceptibility of Opportunistic Actinomycetes Isolated from Immunocompromised and Healthy Patients of Markazi Province of Iran</p>

Abstract

Background: Actinomycetes widely exist in nature and these species cause infections in immunocompromised and healthy patients, although they are frequently found as members of the normal microbiota of humans and animals. These subsequent infections are often misdiagnosed as malignancy and tuberculosis. Due to this issue, the present study aimed to determine the presence and diversity of actinomycetes species causing infections in Iranian patients. Materials and Methods: A total of 79 clinical samples collected from five hospitals in Markazi province were analyzed for the existence of actinomycetes using standard protocols for isolation and characterization of the isolates. The conventional tests were used for preliminary identification, the PCR amplification of hsp65 gene, the specific region of the 16S rRNA, and sequence analyses of 16S rRNA were applied for the genus and species identification. MICs of the antimicrobial agent were determined by the broth microdilution method and interpreted according to the NCCLS guidelines. Results: A total of 17 (21.51%) actinomycetes isolates were recovered from clinical samples. In other analyzed samples, eight (10.12%) gram-positive, 12 (15.18) gramnegative bacteria, and six (7.6) fungi isolates were recovered. The most prevalent actinomycetes species were M. fortuitum (17.64%), N. Mexicana and S. heliomycini (11.76% each), and 10 species, ie, N. farcinica, M. lehmannii, M. flavescens, Arthrobacter crystalopoetis, N. neocaledoniensis, M. phocaicum, M. abscessus, M. arupense, M. setense, and N. cyriacigeorgica made up the single isolates. Results of DST illustrated that all of the isolates were susceptible to Amikacin, Levofloxacin, Ofloxacin, and Ciprofloxacin, whereas all of them were resistant to Rifampicin and Doxycycline. Conclusion: In conclusion, increasing isolation of actinomycetes found in various clinical cases merits special attention by health authorities in developing countries. In health centers, action should be taken to increase awareness of appropriate diagnostic criteria and management guidelines for actinomycetes diseases. Furthermore, an increase in the number as well as the quality of national and regional reference laboratories may facilitate more accurate diagnosis of actinomycetes diseases.

Species diversity and molecular analysis of opportunistic Mycobacterium, Nocardia and Rhodococcus isolated from the hospital environment in a developing country, a potential resources for nosocomial infection

“…The identification of actinomycetes species in the developing countries has been done using conventional microbiological methods such as acid-fast staining, semi-quantitative, and heat-stable (68 °C) catalase production and niacin accumulation, pyrazinamide and growth on MacConkey agar without crystal violet [ 22 ], though isolation and accurate identification of isolates are difficult. Molecular tests that are currently applied provide a conclusive approach for the identification of Nontuberculous Mycobacteria (NTM).…”

Antimicrobial Susceptibility of Clinical Oral Isolates of Actinomyces spp.

“…These genera can develop a remarkable survival ability and can cause life-threatening infections. Reliable identification and susceptibility testing can contribute to reduced mortality [40,41]. Because of the high prevalence of Actinomyces spp.…”

First case of fatal bacteremia due to Nocardia neocaledoniensis

“…In 2012, McGhie et al described the first case of skin and soft tissue infection caused by N. neocaledoniensis in a 68-year-old man on immunosuppressive therapy for rheumatoid arthritis [ 7 ]. In 2020, Azadi et al isolated N. neocaledoniensis from an abscess following a surgery in an immunocompetent patient [ 8 ].…”