Comparison of the Diagnostic Performance of MeltPro and Next-Generation Sequencing in Determining Fluoroquinolone Resistance in Multidrug-Resistant Tuberculosis Isolates

Integrated ecological-health risk assessment of ofloxacin

Antibiotics are emerging contaminants of significant concern, while previous research has mostly focused on their ecological or health impacts in isolation. This limited systematic research on its overall risk and the uncertainty relating to the risk evaluation is also unclear. This study addressed this gap by examining both ecological or health impacts by integrating interspecies correlation models, species sensitivity distribution curves, and health risk evaluation. Then comprehensive risk of antibiotics was calculated using economic approaches. The Wenyu River basin in China and ofloxacin were chosen as the study area and target antibiotic, respectively. The results indicate that both the ecological and health risk quotients for ofloxacin were manageable, and the level of urbanization was found to correlate with increased antibiotic risk. The economic impact on population health was greater than on ecosystems. The presence of ofloxacin in the watershed still resulted in more than $200,000 in annual economic losses, affecting both human society and the ecosystem. The assessment process, including the evaluation object, extrapolated data, and fitted curves, contributed to uncertainty in the results. These findings provide valuable insights for addressing the challenges in assessing the risks of antibiotics, emphasizing the need for integrated assessment frameworks.

Risk factors for poor outcomes in patients with drug-resistant tuberculosis: a 6-year multicenter prospective study in Zhejiang, China

BACKGROUND

At present, the disease burden of drug-resistant tuberculosis (DR-TB) is still heavy in the world. In this study, we aimed to evaluate the success rate of DR-TB patients after standardized treatment and to analyze the risk factors for poor outcomes in Zhejiang, China.

METHODS

From 2017 to 2021, all culture-confirmed tuberculosis (TB) patients were prospectively enrolled from three designated TB hospitals in Zhejiang, China. Demographic surveys were conducted in all patients, and drug susceptibility of TB strains was tested by fluorescent polymerase chain reaction probe melting curve analysis (MeltPro). DR-TB patients were treated with WHO recommended standardized treatment according to the type of drug resistance, and the outcomes were thoroughly monitored and tracked until June 2023. Binary logistic regression model was used to analyze the related risk factors of poor outcomes in patients with DR-TB. The patients' socio-demographic information, comorbidities, fever, antibiotic use, laboratory test results, lung imaging characteristics and drug resistance characteristics were included in the analysis. A simple TB severity score was developed according to the WHO definition and applied to the analysis.

RESULTS

Among 1013 patients with confirmed TB, 779 were sensitive to all of the tested drugs (rifampicin, isoniazid, ethambutol, streptomycin and fluoroquinolones), and 234 were resistant to at least one tested drug. Among the 234 DR-TB patients in the study, 50 patients had poor outcomes (23 cases of failure, 13 cases of death, and 14 patients lost to follow-up), 158 patients were successfully treated (125 cases were cured and 33 cases completed treatment), and 26 were referred to other provinces. The overall treatment success rate was 76.0% (158/208). Multivariate analysis showed that age (AOR 1.03; 95%CI 1.01-1.05), previous TB treatment history (AOR 5.03; 95%CI 1.33-18.99), higher TB severity score (AOR 1.48; 95%CI 1.09-2.03), MDR/RR-TB (AOR 8.34; 95%CI 2.99-23.24) and pre-XDR-TB (AOR 9.50; 95%CI 2.24-40.26) were independent risk factors for poor outcomes in DR-TB patients.

CONCLUSIONS

The treatment success rate of DR-TB patients in this study reached that of the WHO standard treatment (75%). Physicians should be alert to the possibility of poor outcomes in DR-TB patients with old age, previous TB treatment history, higher TB severity score, MDR/RR-TB or pre-XDR-TB.

Analysis of molecular resistance and associated risk factors in tuberculosis

BACKGROUND

Local surveillance of molecular resistance to first-line anti-tuberculosis (TB) drugs and fluoroquinolones (FQs) was initiated in 2019, but existing reports remain limited, hindering effective TB prevention and control efforts. This study aims to investigate molecular resistance to first-line anti-TB drugs and FQs, assess risk factors for FQs resistance, and provide insights into the spread of drug-resistant tuberculosis (DR-TB) to inform more effective control and treatment strategies.

METHODS

Sputum samples from 25,150 non-duplicate patients attending 10 designated TB medical institutions across Luoyang City and all county and township areas under its jurisdiction from January 2019 to December 2023 were analyzed via fluorescence real-time PCR to detect Mycobacterium tuberculosis complex (MTBC)-positive strains. Multicolor melting curve analysis (MMCA) was performed on 4,131 non-repetitive MTBC strains to assess their molecular resistance to first-line anti-TB drugs and FQs. Risk factors for FQs resistance and the impact of first-line anti-TB drug resistance on FQs resistance were also assessed.

RESULTS

Between 2019 and 2023, 4,131 MTBC strains were collected. Resistance to first-line anti-TB drugs was higher in males, retreated patients, individuals younger than 61 years, and those from the main urban area, compared to females, newly diagnosed patients, individuals over 60 years, and residents of county and township areas (59.1% vs. 46.0%, p < 0.001; 85.6% vs. 52.0%, p < 0.001; 60.2% vs. 47.2%, p < 0.001; 47.1% vs. 69.4%, p < 0.001). The overall FQs resistance rate was 7.9% (327 cases). After adjusting for the interaction with first-line anti-TB drugs, the resistance rates to FQs were significantly higher in patients with isoniazid resistance (INH-R), rifampin resistance (RFP-R), and ethambutol resistance (EMB-R), with odds ratios of 2.61 (95% CI 1.77, 3.84, p = 0.002), 4.64 (95% CI 3.13, 6.89, p < 0.001), and 2.86 (95% CI 2.01, 4.07, p < 0.001), respectively, compared to those without resistance.

CONCLUSIONS

Resistance to first-line anti-TB drugs remains high, underscoring the critical role of FQs in TB management. However, the elevated FQs resistance limits their effectiveness against drug-resistant TB. Strengthening DR-TB surveillance and implementing timely, targeted interventions are essential for controlling the spread of DR-TB and achieving the goals of the "End TB Strategy."

Enhanced diagnosis of pulmonary tuberculosis through nucleotide MALDI-TOF MS analysis of BALF: a retrospective clinical study

To evaluate the diagnostic accuracy of matrix-assisted laser desorption ionization time-of-flight mass spectrometry based on nucleotide (nucleotide MALDI-TOF MS) on bronchoalveolar lavage fluid (BALF) from suspected pulmonary tuberculosis (PTB) patients. A retrospective study was conducted on suspected PTB patients (total of 960) admitted to Chongqing Public Health Medical Center between May 2021 and January 2022. The sensitivity, specificity, positive predictive value, negative predictive value (NPV) and area under the curve values of nucleotide MALDI-TOF MS as well as smear microscopy, Mycobacterium Growth Indicator Tube 960 culture (MGIT culture), and Xpert MTB/RIF were calculated and compared. Total of 343 presumed PTB cases were enrolled. Overall, using the clinical diagnosis as reference, the sensitivity and NPV of nucleotide MALDI-TOF MS was 71.5% and 43.1%, respectively, significantly higher than smear microscopy (22.6%, 23.2%), MGIT culture (40.6%, 18.9%), Xpert MTB/RIF (40.8%, 27.9%). Furthermore, nucleotide MALDI-TOF MS also outperformed over Xpert MTB/RIF and MGIT culture on smear-negative BALFs. Approximately 50% and 30% of patients benefited from nucleotide MALDI-TOF MS compared with smear and MGIT culture or Xpert MTB/RIF, respectively. This study demonstrated that the analysis of BALF with nucleotide MALDI-TOF MS provided an accurate and promising tool for the early diagnosis of PTB.

Evaluation of genetic correlation with fluoroquinolones resistance in rifampicin-resistant Mycobacterium tuberculosis isolates

Objective

To detect levofloxacin (LFX) and moxifloxacin (MFX) resistance among rifampicin-resistant tuberculosis (RR-TB) isolates, and predict the resistance level based on specific mutations in gyrA and gyrB genes.

Methods

A total of 686 RR-TB isolates were collected from Chinese Drug Resistance Surveillance Program from 2013 to 2020. The minimum inhibitory concentrations (MICs) of 12 anti-TB drugs were acquired using the broth microdilution method, followed by whole genome sequencing (WGS) analysis.

Results

Among the 686 RR isolates, the most prevalent resistance was to isoniazid (80.5 %) and ethambutol (28.4 %), followed by LFX (26.1 %) and MFX (21.9 %). The resistance rate of LFX (26.1%-99.4 %) was higher than that of MFX (21.9%-83.3 %) across various drug resistance patterns. Of the 180 fluoroquinolones (FQs) resistant isolates, 168 (93.3 %) had mutations in quinolone-resistant determining regions (QRDRs) with 21 mutation types, and Asp94Gly (32.7 %, 55/168) was the predominant mutation. Isolates with mutations in Asp94Asn and Asp94Gly were associated with high levels of resistance to LFX and MFX. Using broth microdilution method as gold standard, the sensitivities of WGS for LFX and MFX were 93.3 % and 98.0 %, and the specificities were 98.6 % and 95.0 %, respectively.

Conclusion

The resistance rate of LFX was higher than that of MFX among various drug resistance patterns in RR-TB isolates. The gyrA Asp94Gly was the predominant mutation type underlying FQs resistance. However, no significant difference was observed between mutation patterns in gyrA gene and resistance level of FQs.

Evaluation of MeltPro Assay in Identification of Second-Line Injectable Drug Resistance in Multidrug-Resistant Tuberculosis Isolates

Objective

We compared the MeltPro assay to whole-genome sequencing (WGS) to investigate the molecular characterization of second-line injectable drug (SLID) resistance in multidrug-resistant tuberculosis (MDR-TB) isolates in Chongqing, China.

Methods

A total of 122 MDR-TB patient isolates were collected between March 2019 and June 2020 from Chongqing Municipality, China. Conventional drug-susceptibility testing was performed using the proportion method, followed to generate minimum inhibitory concentrations (MICs) of SLIDs determined by microplate alamarblue assay. All strains were subjected to both MeltPro and WGS assays.

Results

Among 122 MDR-TB isolates, 30 (24.6%), 22 (18.0%), and 14 (11.5%) were resistant to kanamycin (KM), amikacin (AM), and capreomycin (CM), respectively. Of the 31 SLID-resistant isolates, 24 (77.4%, 24/31) isolates harbored mutations in the rrs gene, with the most prevalent mutations in rrs A1401G (22/24, 91.7%). Mutation in rrs A1401G was associated with high levels of resistance to KM (MIC, ≥40 μg/mL) and AM (MIC, ≥64 μg/mL), but disparities in CM-resistance levels. Using phenotypic drug-susceptibility testing as gold standard, we found that the overall sensitivity of MeltPro and WGS was 87.1% and 90.32% and specificity 100% and 97.8%, respectively. Seven isolates had discordant results between phenotypic and genotypic resistance of SLIDs.

Conclusion

MeltPro is a promising diagnostic tool for accurate identification of SLID-resistant MTB isolates with mutations in the rrs and eis genes. There was a disparity between MeltPro with WGS results in the proportion of heterogeneous drug-resistant bacteria with rrs mutation and limited probes. Resistance mechanisms other than genetic mutations will affect the consistency of MeltPro and WGS with phenotypic drug-susceptibility results.

The positivity rates and drug resistance patterns of Mycobacterium tuberculosis using nucleotide MALDI-TOF MS assay among suspected tuberculosis patients in Shandong, China: a multi-center prospective study

Objective

To investigate the positivity rates and drug resistance characteristics of Mycobacterium tuberculosis (MTB) among suspected tuberculosis (TB) patients in Shandong Province, the second-largest population province in China.

Methods

A prospective, multi-center study was conducted from April 2022 to June 2023. Pathogen and drug resistance were identified using nucleotide matrix-assisted laser desorption ionization time-of-flight mass spectrometry (nucleotide MALDI-TOF MS).

Results

Of 940 suspected TB patients included in this study, 552 cases were found to be infected with MTB giving an overall positivity rate of 58.72%. Total of 346 cases were resistant to arbitrary anti-TB drug (62.68%), with Zibo (76.47%), Liaocheng and Weihai (both 69.23%) ranking top three and TB treatment history might be a related factor. Monoresistance was the most common pattern (33.53%), with isoniazid the highest at 12.43%, followed by rifampicin at 9.54%. Further analysis of gene mutations conferring resistance revealed diverse types with high heteroresistance rate found in multiple anti-TB drugs.

Conclusion

A relatively high rate of MTB positivity and drug resistance was found in Shandong Province during and after the COVID-19 pandemic, indicating the need for strengthening rapid identification of species and drug resistance among suspected TB patients to guide better medication and minimize the occurrence of drug resistance.

Clinical performance of nucleotide MALDI-TOF-MS in the rapid diagnosis of pulmonary tuberculosis and drug resistance

OBJECTIVE

To evaluate the application value of nucleotide matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) technology in the rapid diagnosis of pulmonary tuberculosis (PTB) and its drug resistance.

METHODS

From February 2021 to January 2022, respiratory specimens from 214 suspected PTB patients at the First Hospital of Quanzhou were collected. Nucleotide MALDI-TOF-MS and BACTEC MGIT 960 culture methods were used for the detection of Mycobacterium tuberculosis (MTB) and drug resistance to anti-tuberculosis drugs.

RESULTS

Compared with culture method, nucleotide MALDI-TOF-MS technology had a sensitivity, specificity, and accuracy of 92.2%, 74.1%, and 82.7%, respectively, for the detection of MTB in respiratory specimens. With clinical diagnosis as the reference standard, the sensitivity and accuracy of nucleotide MALDI-TOF-MS were 82.5% and 86.0%, respectively, which were higher than those of the culture method (69.2% and 78.0%, respectively). The specificity of nucleotide MALDI-TOF-MS was 93.0%, which was slightly lower than that of culture method (95.8%). As for drug resistance, the results of nucleotide MALDI-TOF-MS exhibited good consistence with culture methods for rifampin, isoniazid, ethambutol, and streptomycin.

CONCLUSION

Nucleotide MALDI-TOF-MS detection has a good clinical performance for rapid detection of MTB and drug sensitivity to rifampin, isoniazid, ethambutol, and streptomycin directly on respiratory specimens.

Performance of the MeltPro TB assay as initial test for diagnosis of pulmonary tuberculosis with drug-resistance detection

BACKGROUND

The MeltPro TB assay (MeltPro) is a molecular rapid diagnostic test designed for detecting resistance to antituberculosis drugs. However, the performance of MeltPro as an initial diagnostic test for simultaneously detecting the presence of Mycobacterium tuberculosis (MTB) and drug resistance has not been evaluated. This study aims to assess the performance of MeltPro as initial diagnostic test for simultaneous detection of MTB and drug resistance in clinical samples from patients with presumptive pulmonary tuberculosis (PTB).

METHODS

A retrospective analysis was conducted on 1283 patients with presumptive PTB from two clinical centers, out of which 875 were diagnosed with PTB. The diagnostic accuracy of MeltPro, Xpert MTB/RIF (Xpert), and MGIT 960 for PTB detection was evaluated. Rifampicin (RIF), isoniazid (INH), ethambutol (EMB), streptomycin (STR), and fluoroquinolone (FQ) resistance were detected using MeltPro, with Xpert and/or the broth microdilution plate method (MYCOTB) results as references.

RESULTS

For the diagnosis of PTB, MeltPro showed a sensitivity of 69.0%, which was similar to Xpert (72.7%; P > 0.05) and higher than MGIT (58.1%; P < 0.001). The specificity of MeltPro was 97.1%, similar to Xpert (98.0%; P > 0.05). In smear-negative patients, MeltPro's sensitivity was 50.9%, similar to Xpert (56.5%; P > 0.05), and higher than MGIT (33.1%; P < 0.001). Based on Xpert and/or MYCOTB results, MeltPro exhibited a sensitivity and specificity of 98.3% and 99.2%, respectively, for detecting RIF resistance. Based on MYCOTB results, MeltPro's sensitivity for detecting resistance to INH, EMB, STR, and FQ was 96.4%, 89.1%, 97.5%, and 90.3%, respectively, with specificities of 96.0%, 96.0%, 95.2%, and 99.4%, respectively.

CONCLUSION

The MeltPro TB assay could potentially be an effective alternative as the initial test for rapid diagnosis of PTB with drug-resistance detection in clinical practice.