An assessment of nucleic acid amplification testing for active mycobacterial infection
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- Bu səhifədəki naviqasiya:
- Study Number of patients Median time in days to therapy, NAAT (IQR)
- By day: Positive AFB microscopy (%) Positive NAAT (%)
AFB = acid-fast bacilli; NAAT = nucleic acid amplification test; Xpert = GeneXpert MTB/RIF assay Table Median time to therapy using GeneXpert versus comparator
a Xpert-negative, culture-positive participants (N=10); six patients started treatment before the culture result was available. AFB = acid-fast bacilli; IQR = interquartile range; MDR = multi-drug resistant; NAAT = nucleic acid amplification test; Xpert = GeneXpert MTB/RIF assay. The RCT by Theron et al. (2014) also reported the proportion of patients initiating TB treatment and the reasons for treatment initiations, as shown in Table and Figure . The proportion of patients receiving treatment (regardless of reason of initiation) was higher in the Xpert group than in the AFB microscopy group during days 1–9. Furthermore, there were more culture-positive patients on treatment in the Xpert group, compared with the AFB microscopy group, until day 56. Table Proportion of patients initiating treatment based on AFB microscopy or NAAT results, by day
AFB = acid-fast bacilli; NAAT = nucleic acid amplification test Source: Theron et al. (2014) Figure Percentage of patients initiating treatment based on smear (AFB microscopy) or NAAT results, by day Source: Theron et al. (2014) Regarding antibiotic resistance detection, Boehme et al. (2010) reported that the median time for rifampicin resistance results was 1 day (IQR 0–1) for the Xpert NAAT, compared with 20 days (IQR 10–26) for line probe assay and 106 days (IQR 30–124) for phenotypic susceptibility testing. Time-related management results other than median time to diagnosis/treatment after Xpert NAAT were reported in three studies (Lacroix et al. 2008; Marks et al. 2013; Taegtmeyer et al. 2008), all in low-prevalence countries The poor-quality retrospective cohort study by Lacroix et al. (2008) showed that the average delay in TB diagnosis in a public health department in Quebec was decreased by the use of PCR (n=77) compared with no use of PCR (n=38), with a mean of 89.3 days (95%CI 76.4, 102.2) compared with 97.9 days (95%CI 74.2, 121.6; p=0.498), respectively. NAAT (MTD, Gen-Probe, San Diego, California) also significantly decreased the average time to final TB determination for all patients except for those with AFB-negative NAAT-positive culture-negative specimens versus patients with AFB-negative culture-negative (no NAAT) specimens in an unadjusted analysis by Marks et al. (2013). Furthermore, this medium-quality retrospective cohort study, conducted in the USA, reported a multivariable analysis of time to determination of AFB-positive culture-positive patients, and found that a NAAT result reduced the time to TB diagnosis (adjusted hazard ratio = 2.3; 95%CI 1.4, 3.7). A different medium-quality retrospective cohort study (UK) used a INNO-LiPA RIF TB assay (Immunogenetics, Zwijndrecht, Belgium) and compared the mean time to identification of MTB and rifampicin resistance with AFB microscopy and/or mycobacterial culture (Taegtmeyer et al. 2008). The mean time to detection of mycobacteria and rifampicin resistance was 8.8 ± 5.9 days with NAAT compared with 26.0 ± 10.9 days to identification (p=0.001) using culture (without NAAT). In this study, for all the AFB-positive samples, NAAT identified 86% of the samples within 2 weeks, compared with only 7% of samples using culture. Thus, all studies were in agreement that the use of NAAT resulted in a quicker diagnosis of patients with TB, especially in those who were AFB-negative. Predictably, this also resulted in earlier treatment in NAAT-positive patients. Yüklə 3,88 Mb. Dostları ilə paylaş:
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