A prospective study on enhanced recovery of Mycobacterium tuberculosis from children's stool using novel power ultrasound decontamination

Abstract

Stool specimen is commonly used for mycobacterial culture to provide critical microbiological evidence for diagnosing tuberculosis (TB) in pediatric patients, especially when obtaining sputum specimens is challenging. However, the utilization of stool specimens for mycobacterial culture continues to face significant challenges in clinical practice, mainly owing to the relatively low diagnostic sensitivity and the frequent contamination by intestinal flora during specimen processing. This study evaluated the effectiveness of power ultrasound (PU) method in improving the recovery of Mycobacterium tuberculosis (M. TB) from stool specimens collected from children suspected of pulmonary tuberculosis (PTB). A total of 252 stool specimens were collected, and each specimen was subsequently divided into approximately three equal groups. One stool specimen was subjected to direct acid-fast bacilli (AFB) smear microscopy, while the other two stool specimens were processed using different decontamination methods(NaOH-NALC method vs. PU method). Out of the 252 specimens, positive cultures were observed in 14 (5.56%) stool specimens treated with the NaOH-NALC method, including M. TB (n = 11, 4.37%) and non-tuberculous mycobacteria (NTM; n = 3, 1.19%). Similarly, among the stool specimens subjected to the PU method, culture positivity was found in 36 (14.28%), comprising of M. TB (n = 24, 9.52%) and NTM (n = 12, 4.76%). The statistical analysis revealed a significant difference in the isolation rate of M. TB and NTM between the two methods (P<0.001). Furthermore, the contamination rate of stool treated with the PU method (14.28%) is significantly lower than that of the NALC-NaOH method (22.62%). In conclusion, our findings indicate that the PU method is a rapid and effective decontamination method for stool in children, improving the detection of active TB among pediatric populations when compared to the NALC-NaOH method.

Keywords: Mycobacterium tuberculosis; Children; Mycobacterial culture; N-Acetyl-L-Cysteine (NALC)-sodium hydroxide (NaOH); Power ultrasound; Stool.

Fig. 1

The non-contact PU meter and The PU method procedure. (All the photographs were captured directly by our team using a HUAWEI Mate 60 Pro at the Katharine Hsu International Research Center for Human Infectious Diseases and processed using WPS Office software.)

Fig. 2

Patient selection.

Fig. 3

Culture results comparison: NaOH-NALC method vs. PU method. *In the PU method, an additional 13 specimens were identified as positive for M. TB. In contrast, when the same 13 specimens were processed using the NaOH-NALC method, 6 specimens were classified as negative and 7 specimens were contaminated.**In the PU method, an additional 9 specimens were identified as positive for NTM. In contrast, when the same 9 specimens were processed using the NaOH-NALC method, 3 specimens were classified as negative and 6 specimens were contaminated.