A quantitative adaptation of the Wayne test for pyrazinamide resistance

Coronel, Jorge; Gilman, Robert Hugh; Zimic-Peralta, Mirko Juan; Sheen Cortavarria, Patricia; Caviedes, Luz; Proano, Alvaro; Meinzen, Christopher

dc.contributor.author	Meinzen, Christopher
dc.contributor.author	Proano, Alvaro
dc.contributor.author	Gilman, Robert Hugh
dc.contributor.author	Caviedes, Luz
dc.contributor.author	Coronel, Jorge
dc.contributor.author	Zimic-Peralta, Mirko Juan
dc.contributor.author	Sheen Cortavarria, Patricia
dc.date.accessioned	2019-02-06T14:45:55Z
dc.date.available	2019-02-06T14:45:55Z
dc.date.issued	2016
dc.identifier.uri	https://hdl.handle.net/20.500.12866/5119
dc.description.abstract	BACKGROUND: Pyrazinamide (PZA) is the most important drug against the latent stage of tuberculosis (TB) and is used in both first and second line treatment regimens. The continued increase in multi-drug resistant TB and the prevalence of PZA resistance makes the development of alternative assays for prompt identification of PZA resistance all the more important. METHODS: We standardized and evaluated a quantitative variant of the Wayne assay (QW) for determining PZA resistance in Mycobacterium tuberculosis strains. This assay quantifies M. tuberculosis metabolism of PZA and production of pyrazinoic acid (POA) using visible spectrophotometry. We evaluated this method using PZA concentrations of 400 mug/ml and 800 mug/ml at incubation periods of 3, 5 and 7 days. M. tuberculosis strains from 68 sputum samples were also tested with the standard Wayne assay, Tetrazolium Microplate Assay (TEMA), Bactec 460TB and pncA sequencing. We compared QW and standard Wayne assay against a dichotomous reference classification using concordant Bactec 460TB and pncA sequencing. Secondarily, we determined the quantitative correlation between both QW values and TEMA's minimum inhibitory concentration (MIC) against Bactec 460TB percentage growth. RESULTS: The standard Wayne showed sensitivity of 88% and specificity of 97.5%, giving a Youden Index (YI) of 0.855 against reference tests. The QW showed maximum YI of 0.934 on day 7 at 400 mug/ml PZA with 96% sensitivity and 97.4% specificity. Absorbance OD values for 400 mug/ml PZA were more accurate than 800 mug/ml PZA. Although QW showed high accuracy for PZA susceptibility, it did not correlate quantitatively with Bactec percentage growth. TEMA testing was unreliable and did not correlate with Bactec results. CONCLUSIONS: The proposed QW assay is an inexpensive method capable of providing standardization and automation of colorimetric PZA resistance testing, with better discriminatory than the standard Wayne assay.	en_US
dc.language.iso	eng
dc.publisher	Elsevier
dc.relation.ispartofseries	Tuberculosis
dc.rights	info:eu-repo/semantics/restrictedAccess
dc.rights.uri	https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es
dc.subject	Bactec	en_US
dc.subject	Drug Resistance, Bacterial	en_US
dc.subject	Optic density	en_US
dc.subject	Peru	en_US
dc.subject	pncA	en_US
dc.subject	Pyrazinamide	en_US
dc.subject	Pyrazinoic acid	en_US
dc.subject	Resistance	en_US
dc.subject	TEMA	en_US
dc.subject	Tuberculosis	en_US
dc.subject	Wayne	en_US
dc.subject	Adult	en_US
dc.subject	Antitubercular Agents/metabolism/therapeutic use	en_US
dc.subject	Area Under Curve	en_US
dc.subject	Calibration	en_US
dc.subject	Female	en_US
dc.subject	Humans	en_US
dc.subject	Male	en_US
dc.subject	Microbial Sensitivity Tests/methods/standards	en_US
dc.subject	Mycobacterium tuberculosis/drug effects/isolation & purification/metabolism	en_US
dc.subject	Predictive Value of Tests	en_US
dc.subject	Pyrazinamide/analogs & derivatives/metabolism/therapeutic use	en_US
dc.subject	Reference Standards	en_US
dc.subject	Reproducibility of Results	en_US
dc.subject	ROC Curve	en_US
dc.subject	Spectrophotometry	en_US
dc.subject	Sputum/microbiology	en_US
dc.subject	Tuberculosis, Pulmonary/diagnosis/drug therapy/microbiology	en_US
dc.title	A quantitative adaptation of the Wayne test for pyrazinamide resistance	en_US
dc.type	info:eu-repo/semantics/article
dc.identifier.doi	https://doi.org/10.1016/j.tube.2016.03.011
dc.subject.ocde	https://purl.org/pe-repo/ocde/ford#3.02.07
dc.relation.issn	1873-281X