Faculty Collaboration Database

Does neutralization of gastric aspirates from children with suspected intrathoracic tuberculosis affect mycobacterial yields on MGIT culture? J Clin Microbiol 2013 Jun;51(6):1753-6

Date

03/29/2013

Pubmed ID

23536406

Pubmed Central ID

PMC3716107

DOI

10.1128/JCM.00202-13

Scopus ID

2-s2.0-84878503405 (requires institutional sign-in at Scopus site)   20 Citations

Abstract

The microbiological confirmation of pulmonary tuberculosis in children relies on cultures of gastric aspirate (GA) specimens. Conventionally, GAs are neutralized to improve culture yields of mycobacteria. However, there are limited data to support this practice. To study the utility of neutralization of GAs with sodium bicarbonate in children with intrathoracic tuberculosis, a total of 116 children of either sex, aged 6 months to 14 years (median age, 120 months; interquartile range [IQR], 7 to 192 months), underwent gastric aspiration on 2 consecutive days. Gastric aspirates were divided into two aliquots, and only one aliquot was neutralized with 1% sodium bicarbonate. Both aliquots were processed for smear and culture examinations. Out of the 232 gastric aspirates, 12 (5.17%) were acid-fast bacilli (AFB) smear positive. There were no differences in smear positivity rates from samples with or without neutralization. The yield of Mycobacterium tuberculosis on a Bactec MGIT 960 culture system was significantly lower in the neutralized samples (16.3% [38/232]) than in the nonneutralized samples (21.5% [50/232]) (P = 0.023). There was no significant difference between the neutralized and the nonneutralized samples in time to detection using the MGIT 960 system (average, 24.6 days; IQR, 12 to 37 days) (P = 0.9). The contamination rates were significantly higher in the neutralized samples than in the nonneutralized samples (17.2% [40/232] versus 3.9% [9/232]) (P = 0.001). The agreement for positive mycobacterial culture between the two approaches was 66.5% (P = 0.001). Hence, we recommend that gastric aspirate samples not be neutralized with sodium bicarbonate prior to culture for M. tuberculosis.

Author List

Parashar D, Kabra SK, Lodha R, Singh V, Mukherjee A, Arya T, Grewal HM, Singh S, Delhi Pediatric TB Study Group

Author

Deepak Parashar PhD Assistant Professor in the Medicine department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adolescent
Bacteriological Techniques
Child
Child, Preschool
Female
Gastric Juice
Humans
Hydrogen-Ion Concentration
Infant
Male
Mycobacterium tuberculosis
Prospective Studies
Sodium Bicarbonate
Specimen Handling
Stomach
Tuberculosis, Pulmonary