Pattern of Rapidly growing Mycobacteria (RGM) species isolated from clinical samples: A 10-year retrospective study in a tertiary care hospital of Bangladesh.

Purpose: Infections caused by rapidly growing mycobacteria (RGM) are increasing worldwide. The study was conducted in a microbiological laboratory of Bangladesh to determine the pattern of detection of RGM from clinical samples.

Methods: All laboratory culture records of RGM from 2012 to 2022 were collected retrospectively and analyzed.

Results: A total 62 RGM infected patients with surgical site infection (74.1%), injection site and skin abscess (9.7%), septicemia (4.8%) and UTI (1.6%) were identified. The annual isolation frequency of RGM increased 4.8% to 29.1% in between year 2012 and 2022. RGM infected patients (14.5%) were mistakenly treated with first line anti tubercular drug before correct microbiological diagnosis (median, IQR; 3, 2-5 months). Out of 23 RGM isolates, 86.9% were M. abscessus and rest 13.1% were M. fortuitum. Most of them (≥95%) were sensitive to amikacin, linezolid, clarithromycin where as 27.1% to imipenem and ciprofloxacin, 40% to cefoxitin, 35.3% and 1.7% to doxycycline and co-trimoxazole respectively.

Conclusion: Misdiagnosis or delay in diagnosis and erroneous treatment with first line anti tubercular drug may cause prolong morbidity and therapeutic failure to patients with RGM infection. So, early and appropriate diagnosis is crucial for successful outcome.