Differential distribution of linezolid in diseased and nondiseased bones in patients with spinal tuberculosis.

BACKGROUND: Linezolid exhibits antibacterial activity against sensitive and drug-resistant strains of Mycobacterium tuberculosis. Knowledge on the distribution of linezolid in different types of bones in patients with spinal tuberculosis (TB) is lacking, which limits the pharmacokinetic and pharmacodynamic studies of linezolid. This study aimed to evaluate the distribution of linezolid in diseased and nondiseased bones in patients with spinal TB. METHODS: Spinal TB patients treated with linezolid-containing regimens and whose diseased and nondiseased bones were collected during surgery were enrolled retrospectively from January 2017 to February 2022. Blood, nondiseased bones, and diseased bones were collected simultaneously during the operation. Linezolid concentrations in the plasma, nondiseased bones, and diseased bones were subjected to high-performance liquid chromatography-tandem mass spectrometry. RESULTS: Seven eligible spinal TB patients, including one rifampicin-resistant case, were enrolled. Following a 600 mg oral administration of linezolid before surgery, the median concentrations of linezolid in plasma, nondiseased bone, and diseased bone of the seven patients were 8.23, 1.01, and 2.13 mg/L, respectively. The mean ratios of linezolid concentration in nondiseased bones/plasma, diseased bones/plasma and diseased bones/nondiseased bones reached 0.26, 0.49, and 2.27, respectively. The diseased bones/plasma presented a higher mean ratio of linezolid concentration than nondiseased bones/plasma, and the difference was statistically significant (t = 2.55, p = 0.025). Pearson's correlation analysis showed the positively correlation of linezolid concentrations in diseased and nondiseased bones (r = 0.810, p = 0.027). CONCLUSIONS: Linezolid exhibits a higher concentration distribution in diseased bones than in nondiseased bones.

Corrigendum: Diagnostic efficiency of metagenomic next-generation sequencing for suspected spinal tuberculosis in China: a multicenter prospective study.

[This corrects the article DOI: 10.3389/fmicb.2022.1018938.].

Diagnostic efficiency of metagenomic next-generation sequencing for suspected spinal tuberculosis in China: A multicenter prospective study.

Background: The pathogens of suspected spinal tuberculosis (TB) include TB and non-TB bacteria. A rapid and effective diagnostic method that can detect TB and non-TB pathogens simultaneously remains lacking. Here, we used metagenomic next-generation sequencing (mNGS) to detect the pathogens in patients with suspected spinal TB. Methods: The enrolled patients with suspected spinal TB were regrouped three times into patients with spinal infection and controls, patients with spinal TB and controls, and patients with non-TB spinal infection and controls. We tested the three groups separately by using mNGS and conventional detection methods. Results: Ultimately, 100 patients were included in this study. Pathogens were detected in 82 patients. Among the 82 patients, 37 had TB and 45 were infected with other bacteria. In patients with spinal infection, the sensitivity of the mNGS assay was higher than that of culture and pathological examination (p < 0.001, p < 0.001). The specificity of the mNGS assay was not statistically different from that of culture and pathological examination (p = 1.000, p = 1.000). In patients with spinal TB, no statistical difference was found between the sensitivity of the mNGS assay and that of Xpert and T-SPOT.TB (p = 1.000, p = 0.430). The sensitivity of the mNGS assay was higher than that of MGIT 960 culture and pathological examination (p < 0.001, p = 0.006). The specificities of the mNGS assay, Xpert, MGIT 960 culture, and pathological examination were all 100%. The specificity of T-SPOT.TB (78.3%) was lower than that of the mNGS assay (100%; p < 0.001). In patients with non-TB spinal infection, the sensitivity of the mNGS assay was higher than that of bacterial culture and pathological examination (p < 0.001, p < 0.001). The specificity of the mNGS assay was not statistically different from that of bacterial culture and pathological examination (p = 1.000, p = 1.000). Conclusion: Data presented here demonstrated that mNGS can detect TB and non-TB bacteria simultaneously, with high sensitivity, specificity and short detection time. Compared with conventional detection methods, mNGS is a more rapid and effective diagnostic tool for suspected spinal TB.

The Comparative Influence of 2 and 4 Weeks Preoperative Antituberculosis Treatment on Spinal Tuberculosis Surgery: A Multicenter, Prospective, Randomized Clinical Trial.

INTRODUCTION: A trade-off between successful surgery and minimizing the operation delay for patients with spinal tuberculosis (TB) is a major consideration to determine the duration of preoperational anti-TB treatment (AAT). In this study, 2 and 4 weeks preoperative AAT durations were compared for their influence on the operation outcomes. METHOD: A multicenter, prospective, randomized trial was conducted in four hospitals in China. New patients with spinal TB were recruited and randomly allocated to two groups (2 or 4 weeks' preoperative treatment) and administered the standardized first-line anti-TB drugs. The symptom changing and indicators reflecting recovery and side effects of the treatment were monitored. Patient was followed up for another 18 months after completion of treatment. RESULTS: In total, 150 eligible patients were enrolled between June 2014 and December 2016, and 13 patients were excluded after the enrollment. The remaining 137 participants were randomly allocated to the 2-week group (n = 68) or the 4-week group (n = 69). These two groups acquired similar surgical outcomes, considering wound healing rate within 3 months after the operation (94.20%, 65/69 vs 89.71%, 61/68; P = 0.333) and bony fusion rate within 6 months (98.46%, 64/65 vs 95.45%, 63/66; P = 0.317). However, the culture positive rate of pus collected during operation in the 4-week group (41.94%) was significantly lower than that of the 2-week group (60.94%, P = 0.033). No reoccurrence of disease was observed in either group during the 18-month follow-up period. CONCLUSION: Patients with spinal TB administered 2 or 4 weeks of preoperative anti-TB treatment acquired similar surgical outcomes. However, patients who underwent the operation sooner suffered 2 weeks less agony from the disease.

Bone penetration of linezolid in osteoarticular tuberculosis patients of China.

BACKGROUND: Linezolid presents strong antimicrobial activity against multidrug-resistant (MDR) pulmonary tuberculosis (TB), but its application in osteoarticular tuberculosis treatment remains understudied. Our objective was to analyze the bone penetration efficiency of linezolid in osteoarticular TB patients. METHODS: Osteoarticular TB patients, treated with 600 mg q 24 h linezolid-containing regimens and undergoing surgery, were prospectively and consecutively enrolled. One dose linezolid was administered before surgery. Blood and bone samples were collected simultaneously during operation, and their linezolid concentrations were then detected using high-performance liquid chromatography-tandem mass spectrometry. Pus samples were subjected to mycobacterial culture and GeneXpert MTB/RIF assay. The minimum inhibition concentrations (MICs) and drug susceptibility testing were performed with the recovered isolates. RESULTS: A total of 36 eligible osteoarticular TB patients were enrolled, including five MDR/rifampicin-resistant cases. All the 12 recovered isolates had MICs ≤0.5 µg/mL for linezolid. Mean concentrations in plasma, collected 100-510 min after the preoperative dosing, were 10.43 ± 4.83 µg/mL (range 3.29-22.26 µg/mL), and median concentrations in bone were 3.93 µg/mL (range 0.61-16.34 µg/mL). The median bone/plasma penetration ratio was 0.42 (range 0.14-0.95 µg/mL). Linezolid concentration in bone had a linear correlation with the drug concentration in plasma (r = 0.7873, p < 0.0001), while plasma concentration could explain 61.98% of the variation of concentration in bone (R2 = 0.6198). Notably, stratification analysis by sampling time demonstrated that samples collected 200-510 min after dosing had very good linear relationships between their bone and plasma concentrations (r = 0.9323). CONCLUSIONS: Linezolid penetrates from blood to bone efficiently, and the penetration further stabilizes ∼3 h after dosing.

Distribution of Linezolid in Tuberculosis Lesions in Patients with Spinal Multidrug-Resistant Tuberculosis.

Linezolid has strong antimicrobial activity against the multidrug-resistant (MDR) strains of Mycobacterium tuberculosis Little is known about the distribution of linezolid in tuberculosis (TB) lesions in patients with MDR-TB. The aim of this study was to evaluate the distribution of linezolid in TB lesions in patients with spinal MDR-TB. Nine patients with spinal MDR-TB were enrolled prospectively from August 2019 to February 2020. The patients received a linezolid-containing anti-TB treatment regimen and needed surgery for the removal of TB lesions. During the operation, nine blood samples, eight diseased bone tissue samples, seven pus samples, and four granulation tissue samples were collected simultaneously and 2 h after the oral administration of 600 mg of linezolid. Linezolid concentrations in plasma, diseased bone tissue, pus, and granulation tissue samples were subjected to high-performance liquid chromatography-tandem mass spectrometry. At sample collection, the mean concentrations of linezolid in plasma, diseased bone tissue, pus, and granulation tissue samples of the nine patients were 11.14 ± 5.82, 5.94 ± 4.27, 11.09 ± 4.58, and 14.08 ± 10.61 mg/liter, respectively. The mean ratios of linezolid concentration in diseased bone/plasma, pus/plasma, and granulation/plasma were 53.84%, 91.69%, and 103.57%, respectively. The mean ratios of linezolid concentration in pus/plasma and granulation/plasma were higher than those in diseased bone/plasma, and the difference was statistically significant (t = -2.810, P = 0.015; t = -4.901, P = 0.001). In conclusion, linezolid had different concentration distributions in different types of TB-infected tissues in patients with spinal MDR-TB.

Penetration of linezolid into bone tissue 24 h after administration in patients with multidrug-resistant spinal tuberculosis.

BACKGROUND: Linezolid has shown strong antimicrobial activity against multidrug-resistant (MDR)/rifampin-resistant strains of Mycobacterium tuberculosis. Linezolid achieves clinical efficacy mainly through area under the concentration time curve/minimum inhibitory concentration ratio in the infected lesion site. Previous studies mainly focused on the relationship between linezolid concentrations in the blood and infected bone tissue when the blood drug concentration reached the peak 2 h after administration. However, we do not know whether linezolid can maintain the same bone/plasma ratio in infected bone tissue when the blood concentration reaches the trough level. Therefore, this study aimed to evaluate the penetrability of linezolid into bone tissue 24 h after administration in patients with MDR spinal tuberculosis (TB). METHODS: Nine MDR spinal TB patients, who received a treatment regimen including linezolid and underwent surgery, were enrolled prospectively from April 2017 to March 2019. Blood and diseased bone tissue specimens were collected simultaneously during operations 24 h after taking 600 mg of linezolid orally. Linezolid concentrations in plasma and diseased bone tissue specimens were determined by high-performance liquid chromatography-tandem mass spectrometry. RESULTS: Following a 600 mg oral administration of linezolid 24 h before surgery, median concentrations of linezolid in plasma and diseased bone tissue for the 9 patients were 1.98 mg/L (range 0.30-3.44 mg/L) and 0.60 mg/L (range 0.18-2.13 mg/L), respectively, at resection time. The median diseased bone/plasma linezolid concentration ratio was 0.48 (range 0.30-0.67). Pearson's correlation analysis showed that linezolid concentrations in the plasma were positively related to those in diseased bone tissue (r = 0.949, p < 0.001). CONCLUSIONS: After 24 h of medication, linezolid still had good penetrability into diseased bone tissue in patients with MDR spinal TB.

Diagnostic accuracy evaluation of the conventional and molecular tests for Spinal Tuberculosis in a cohort, head-to-head study.

Early diagnosis of spinal tuberculosis (TB) is hampered by the flaws of conventional tests. The aim of this study was to assess the value of new and existing molecular tests in a prospective, head-to-head cohort study. Specimens were consecutively collected from spinal TB suspects in four hospitals in Beijing, China. Smear, culture, histopathology, Xpert MTB/RIF (Xpert), and MeltPro TB assays were performed in parallel using the same specimen from each patient. Drug-susceptibility testing (DST) was conducted on the isolates recovered. In total, 438 suspects were recruited; 319 of them were diagnosed with spinal TB according to the composite reference standard (CRS), which was composed of clinical, laboratory, histopathological, and radiological examinations and 18 months of follow-up. Based on conventional testing, 74.29% of patients were classified as confirmed cases, which increased to 90.6% when Xpert outcomes were integrated. Further, 76.60% of probable and 45.71% of possible cases were re-classified as confirmed cases with Xpert. Xpert (85.27%) produced higher sensitivity than histopathology (73.04%), MeltPro TB (57.68%), culture (51.72%) and smear (24.45%) (all P <0.001). Xpert was 100% concordant with phenotypic DST regarding rifampicin resistance detection. The sensitivity and specificity of MeltPro TB for rifampicin resistance detection were 100% and 97.96%, respectively, and 95.00% and 93.88% for isoniazid resistance detection. New molecular tests demonstrated excellent efficiency for spinal TB diagnosis in this cohort study, so their application as initial diagnostic tools would greatly increase the proportion of confirmed cases and dramatically reduce the delay of appropriate treatment. An updated laboratory testing algorithm of the disease is desirable.

Evaluation of interferon-γ release assay in the diagnosis of osteoarticular tuberculosis.

The aim of this study was to assess the value of interferon-γ (IFN-γ) release assay (IGRA) (T-SPOT.TB) for patients with suspected osteoarticular tuberculosis (TB) in comparison with conventional and molecular methods. Of 145 patients with suspected osteoarticular TB, recruited from Beijing Chest Hospital between July 2011 and June 2012, 86 (59.3%)had osteoarticular TB (26 with culture-confirmed TB, 60 with probable TB), 24 (16.6%) were not having active TB. The remaining 17 (11.7%) inconclusive TB and 18 (12.4%) possible TB were excluded from final analysis. In addition to conventional tests and molecular method, T-SPOT.TB assay using peripheral blood mononuclear cells to examine IFN-γ response to early secretory antigenic target 6 and culture filtrate protein 10 was also performed. The sensitivity and specificity for T-SPOT.TB assay were 94.2% and 70.8%, respectively. A statistically significant difference in sensitivity was found between T-SPOT.TB assay (94.2%) and other tests (acid-fast bacilli smear (19.7%), culture (34.2%), real-time PCR (36.8%); P < 0.01, respectively). These results suggested that the IGRA assay could provide useful aids in the diagnosis of osteoarticular TB.

[Analysis of failure reasons for postoperative patients of spinal tuberculosis complicated with paraplegia of 32 cases].

OBJECTIVE: To discuss the failure reasons of operation for spinal tuberculosis complicated with paraplegia and methods of the second operation. METHODS: Spinal tuberculosis paraplegic patients (18 males, 14 females) were reviewed retrospectively. They have been treated with failing decompressive surgery from January 2001 to December 2006. Seventeen patients received anterior debridement surgery via transpleural approach while the other 15 patients received posterolateral decompression surgery via costotransverse approach. Twenty-two patients got chemotherapy after the surgery. RESULTS: Twenty-three patients were treated by anterior debridement, decompression and graft placement via transpleural approach (9 received the single-stage posterior instrumentation). Five patients received posterolateral debridement and decompression via extrapleural approach. Two patients, recur focus be eliminated. Two patients were given sinus debridement surgery alone. All patients were given anti-tuberculosis chemotherapy. The paraplegia was recovered completely in 26 patients, and partly in 5 patients. CONCLUSIONS: Inadequate treatment results in defeated operative. The proper selection of operative modalities and timing on the basis of systematically anti-tuberculosis chemotherapy remains the best mode of therapy for spinal tuberculosis complicated with paraplegia. And it is also essential to choose a radical debridement surgery to decompress the spinal cord and to reconstruct the stability of spine.