Drug Susceptibility and Mutation Profiles in Mycobacterium tuberculosis Isolates from a Tertiary Care Hospital in Kerala, India.

The rising prevalence of drug-resistant Mycobacterium tuberculosis (MTB) strains poses a significant challenge to global tuberculosis (TB) control efforts. This study aimed to analyze drug resistance patterns and investigate the molecular characteristics of 193 MTB clinical isolates to shed light on the mechanisms of drug resistance. Of the 193 MTB clinical isolates, 28.5% (n = 53) exhibited mono-drug or multidrug resistance. Pyrazinamide mono-drug resistance (PZAr) was the most prevalent (17%, n = 33), followed by isoniazid mono-drug resistance (3.6%, n = 7). Rifampicin resistance was associated with mutations in the rpoB gene (D435Y, D435V, S450L, L452P). Isoniazid resistance mutations were found in the katG (S315T), inhA (C[-15] T), and ndh (R268H) genes, whereas ethambutol resistance mutations were observed in the embB gene (M306V, M306I, M306L, G406S, Q497R). Surprisingly, 94% of PZAr isolates (n = 31) showed no mutations in the pncA or rpsA genes. The presence of the R268H mutation in the ndh gene, not previously linked to PZAr, was detected in 15% of PZAr isolates (n = 5), suggesting its potential contribution to PZAr in specific cases but not as a predominant mechanism. The specific molecular mechanisms underlying PZAr in the majority of the isolates remain unknown, emphasizing the need for further research to uncover the contributing factors. These findings contribute to the understanding of drug resistance patterns and can guide future efforts in TB control and management.

Epidemiology of Nontuberculous Mycobacterial Infection in Tuberculosis Suspects.

Nontuberculosis mycobacteria (NTM) are opportunistic pathogens that cause a wide range of illnesses. Here, the species distribution and prevalence of NTM infections in tuberculosis suspects was analyzed. A total of 7,073 specimens from pulmonary and extrapulmonary sites were analyzed, and 709 (10%) were found to be culture positive for mycobacteria. Of these, 85.2% were identified as Mycobacterium tuberculosis complex and 14.8% as NTM (65.7% rapid growers and 34.3% slow growers). Speciation of the NTM isolates (n = 69) identified 19 NTM species. M. abscessus (33.3%) and M. fortuitum (24.6%) were the most dominant NTM species isolated from the patients, followed by M. porcinum (5.8%) and M. parascrofulaceum (4.3%). We also report peritonitis caused by rapidly growing NTM among the patients undergoing continuous ambulatory peritoneal dialysis and a case of M. senegalense peritonitis. A low prevalence but high species diversity of NTM was detected in our study. The high species diversity of NTM necessitates the need to unequivocally identify mycobacterial isolates for appropriate treatment.

Exophiala dermatitidis as a cause of central line associated bloodstream infection in an infant: Case report and literature review / Exophiala dermatitidis como causante de infección del torrente sanguíneo asociada a catéter central en un lactante: reporte de un caso y revisión de la literatura

BACKGROUND: Exophiala dermatitidis is a dematiaceous fungus known to cause superficial, subcutaneous, cutaneous and deep seated infections, and rarely central line associated bloodstream infection (CLABSI). A case of CLABSI due to E. dermatitidis in an infant is described. CASE REPORT: Clinical and laboratory data were extracted from patient's chart and laboratory records. The isolate was identified as E. dermatitidis by phenotypic characterization and sequencing of the ITS and LSU regions of the ribosomal DNA. Medline search was done to review all cases of CLABSI due to E. dermatitidis. Among the azoles tested, posaconazole (0.06mg/l), voriconazole (0.03mg/l) and itraconazole (0.03mg/l) showed very low MICs when compared to fluconazole (4mg/l). CONCLUSIONS: As we did not found in the literature any case of CLABSI due to E. dermatitidis in an infant, we report the first one. Sequencing is a mandatory method for accurately identifying this species. Prompt removal of the central line, followed by a treatment with amphotericin B or an azole, seems to be the most effective treatment

ANTECEDENTES: Exophiala dermatitidis es un hongo dematiáceo conocido por causar infecciones superficiales, subcutáneas, cutáneas y profundas, y rara vez infección del torrente sanguíneo asociada a catéter central (central line associated bloodstream infection [CLABSI]). Se describe un caso de CLABSI debido a E. dermatitidis en un bebé. CASO CLÍNICO: Los datos del paciente se extrajeron de la historia clínica y de los registros de laboratorio. El aislamiento se identificó como E. dermatitidis mediante caracterización fenotípica y la secuenciación de las regiones ITS y LSU del ADN ribosómico. Se realizó una búsqueda en Medline para revisar todos los casos de CLABSI debidos a E. dermatitidis. Entre los azoles evaluados, el posaconazol (0,06mg/l), el voriconazol (0,03mg/l) y el itraconazol (0,03mg/l) mostraron valores de MIC muy bajos en comparación con el fluconazol (4mg/l). CONCLUSIONES: Tras la revisión de todo lo publicado en la literatura, presentamos el primer caso de CLABSI debido a E. dermatitidis en un lactante. La secuenciación es necesaria para identificar con precisión esta especie. La retirada inmediata del catéter venoso central seguida de un tratamiento con anfotericina B o un azol es el tratamiento más efectivo

Exophiala dermatitidis as a cause of central line associated bloodstream infection in an infant: Case report and literature review.

BACKGROUND: Exophiala dermatitidis is a dematiaceous fungus known to cause superficial, subcutaneous, cutaneous and deep seated infections, and rarely central line associated bloodstream infection (CLABSI). A case of CLABSI due to E. dermatitidis in an infant is described. CASE REPORT: Clinical and laboratory data were extracted from patient's chart and laboratory records. The isolate was identified as E. dermatitidis by phenotypic characterization and sequencing of the ITS and LSU regions of the ribosomal DNA. Medline search was done to review all cases of CLABSI due to E. dermatitidis. Among the azoles tested, posaconazole (0.06mg/l), voriconazole (0.03mg/l) and itraconazole (0.03mg/l) showed very low MICs when compared to fluconazole (4mg/l) CONCLUSIONS: As we did not found in the literature any case of CLABSI due to E. dermatitidis in an infant, we report the first one. Sequencing is a mandatory method for accurately identifying this species. Prompt removal of the central line, followed by a treatment with amphotericin B or an azole, seems to be the most effective treatment.