focalinterest.net

Tag: Infectious Diseases

  • Delayed tuberculosis visits increased in Shenyang from 2015 to 2024

    What the study found

    The study found that more than half of tuberculosis (TB) patients in Shenyang City experienced a delay in consultation, and the delay rate increased over time from 2015 to 2024. Women, adults aged 60 years or older, ethnic minority patients, and patients with positive pathology results had higher odds of delay.

    Why the authors say this matters

    The authors conclude that timely detection and diagnosis of TB are important for preventing disease spread and worsening illness. They suggest that intervention strategies should target risk factors and key populations to reduce patients' suffering and economic losses.

    What the researchers tested

    The researchers retrospectively analyzed consultation delay among TB patients in Shenyang City, Liaoning Province, using records from the China Tuberculosis Information Management System (TBIMS). They included patients from January 1, 2015, to December 31, 2024, and used descriptive statistics, chi-square tests, and binary logistic regression to examine factors linked to delay.

    What worked and what didn't

    A total of 38,928 TB patients were included. The median delay in consultation was 18 days, and 22,051 patients (56.65%) had delayed consultation, with an increasing trend across the study period. Female sex, age 60 years or older, ethnic minority status, and positive pathology were associated with greater delay, while intracity mobility and patient origin as a physical examination were associated with lower delay.

    What to keep in mind

    This was a retrospective analysis of surveillance data from one city, so the findings are specific to Shenyang City and the available records. The abstract does not describe additional limitations.

    • More than half of the 38,928 TB patients had delayed consultation.
    • The median consultation delay was 18 days.
    • The delay rate increased from 2015 to 2024.
    • Higher delay odds were seen in women, older adults, ethnic minority patients, and patients with positive pathology.
    • Intracity mobility and detection through physical examination were associated with lower delay.

  • Mycobacterium exposure detected in domestic sows and wild boars in Korea

    What the study found

    The study found serologic evidence of exposure to Mycobacterium bovis and Mycobacterium avium in both domestic sows and wild boars in Korea. The authors report that Mycobacterium avium exposure varied by province in domestic sows, while province-level variation was not seen in wild boars.

    Why the authors say this matters

    The authors conclude that the findings indicate ongoing environmental exposure to mycobacteria in Korean suids, meaning pigs and related animals. They say the results support integrated One Health surveillance that includes domestic pigs, wildlife, and additional diagnostic methods.

    What the researchers tested

    The researchers analyzed serum samples collected between February 2023 and November 2024 from 1,366 domestic sows and 1,168 wild boars across nine administrative provinces in the Republic of Korea. They used validated commercial enzyme-linked immunosorbent assays, or ELISAs, to estimate apparent seroprevalence, which is the share of animals with detectable antibodies in blood.

    What worked and what didn't

    Apparent seroprevalence of Mycobacterium bovis was 4.54% in domestic sows and 5.91% in wild boars. Apparent seroprevalence of Mycobacterium avium was 10.10% in domestic sows and 7.71% in wild boars, and significant provincial variation was detected only for Mycobacterium avium in domestic sows, driven by higher seropositivity in Gyeonggi Province.

    What to keep in mind

    The abstract notes that ELISA-based serology reflects exposure rather than active infection, so the results should be interpreted with caution. The summary does not describe other limitations beyond that point.

    • Domestic sows and wild boars in Korea showed serologic evidence of exposure to Mycobacterium bovis and Mycobacterium avium.
    • Mycobacterium bovis apparent seroprevalence was 4.54% in domestic sows and 5.91% in wild boars.
    • Mycobacterium avium apparent seroprevalence was 10.10% in domestic sows and 7.71% in wild boars.
    • Significant province-level variation was found only for Mycobacterium avium in domestic sows, with higher seropositivity in Gyeonggi Province.
    • The authors say the findings support integrated One Health surveillance involving domestic pigs, wildlife, and complementary diagnostics.

  • PET/CT lesion responses matched tuberculosis treatment outcomes in marmosets

    What the study found

    The study found that quantitative PET/CT (positron emission tomography/computed tomography) measures of tuberculosis lung lesions in infected marmosets aligned with known clinical outcomes. The authors report that these imaging-based response profiles were more informative than bacterial burden alone.

    Why the authors say this matters

    The authors conclude that PET/CT-based lesion measures may help interpret treatment efficacy and better understand clinical treatment outcomes in pulmonary tuberculosis. They also suggest these measures can provide lesion-level insight into clinical success and failure.

    What the researchers tested

    The researchers measured radiographic changes in lung lesions in infected marmosets using PET/CT imaging. The animals were divided into 22 treatment arms, including monotherapies and combination drug treatments, and treated for 2 months. They then used unsupervised clustering to combine imaging changes with terminal bacterial burden per lung lesion.

    What worked and what didn't

    The drug response profiles matched histopathological classifications at necropsy and could distinguish cavitary granulomas that responded to treatment from those that failed to improve or worsened after the first month. The inferiority of the 4-month moxifloxacin-rifampicin-pyrazinamide-ethambutol regimen compared with the 6-month standard of care for lung cavitary tuberculosis could be predicted. The study also found that PET/CT measures were more informative of treatment outcomes than bacterial burden.

    What to keep in mind

    The study was done in infected marmosets, so the findings are limited to this animal model in the available summary. The abstract does not describe additional limitations.

    • PET/CT-based lung lesion measures aligned with known clinical tuberculosis treatment outcomes.
    • The study used infected marmosets split into 22 treatment arms, including mono- and combination therapies.
    • Unsupervised clustering combined imaging changes with terminal bacterial burden per lung lesion.
    • The response profiles matched histopathology at necropsy.
    • The 4-month moxifloxacin-rifampicin-pyrazinamide-ethambutol regimen was predicted to be inferior to 6-month standard treatment for lung cavitary tuberculosis.

  • Tongue swab PCR showed high accuracy for tuberculosis detection

    What the study found

    The study found that rapid PCR (polymerase chain reaction, a method for detecting genetic material) testing of tongue swabs was accurate for detecting pulmonary tuberculosis in sputum-scarce patients. It was especially specific, meaning it rarely gave positive results when tuberculosis was not present.

    Why the authors say this matters

    The authors conclude that tongue swab-based PCR is a noninvasive, accurate, and highly specific diagnostic approach for tuberculosis, especially for sputum-scarce or sputum-negative individuals. They also suggest that adding it to routine TB diagnostic algorithms could enhance case detection, strengthen drug resistance surveillance, and contribute to reducing transmission.

    What the researchers tested

    The researchers enrolled 625 sputum-scarce people with presumptive tuberculosis at four TB hospitals in China. Each participant provided paired tongue swab and bronchoalveolar lavage fluid (BALF, fluid collected from the lower airways) specimens; the tongue swabs were tested with an MTB-specific PCR assay, and the BALF samples were evaluated with a microbiological reference standard and Xpert MTB/RIF.

    What worked and what didn't

    Against the microbiological reference standard, tongue swab testing had 79.9% sensitivity and 99.5% specificity. Against Xpert MTB/RIF, it had 81.7% sensitivity and 97.6% specificity. Simulation modeling also showed that when sputum-scarce patients made up more than 10% of cases, the tongue swab PCR strategy outperformed conventional sputum-only Xpert MTB/RIF testing in overall case detection rates.

    What to keep in mind

    The authors note that further optimization of sampling protocols and molecular assays is needed to improve detection sensitivity in cases with low bacillary loads (low numbers of tuberculosis bacteria). The summary does not describe other limitations.

    • Tongue swab PCR showed 79.9% sensitivity and 99.5% specificity against the microbiological reference standard.
    • The same test showed 81.7% sensitivity and 97.6% specificity against Xpert MTB/RIF.
    • The study enrolled 625 sputum-scarce people with presumptive tuberculosis at four Chinese TB hospitals.
    • Simulation modeling found the tongue swab PCR strategy outperformed sputum-only Xpert MTB/RIF when sputum-scarce patients exceeded 10% of cases.
    • The authors said more optimization is needed for samples with low bacillary loads.

  • MRI scores differentiated pyogenic and tuberculous spondylitis

    What the study found

    The study found that two MRI-based measures, the epidural abscess signal (EAS) score and vertebral body signal (VBS) score, helped differentiate pyogenic spondylitis from tuberculous spondylitis. Pyogenic spondylitis refers to a spinal infection caused by bacteria, while tuberculous spondylitis is caused by tuberculosis.

    Why the authors say this matters

    The authors say this matters because the two conditions need different antimicrobial treatment regimens, so early distinction is important for clinical management. The study suggests these MRI scores may help guide empirical antibiotic therapy before microbiological confirmation.

    What the researchers tested

    The researchers studied patients with definitive etiological or pathological diagnoses from two tertiary centers. They used a retrospective derivation cohort of 88 patients and a prospective validation cohort of 34 patients, then calculated EAS from T2-weighted MRI and VBS from T1-weighted MRI and assessed performance with receiver operating characteristic analysis and multivariable logistic regression.

    What worked and what didn't

    In both cohorts, patients with pyogenic spondylitis had higher EAS scores and lower VBS scores than patients with tuberculous spondylitis, with all reported comparisons at p < 0.001. In the derivation cohort, EAS ≥ 0.400 and VBS ≤ 2.000 were identified as optimal thresholds for pyogenic spondylitis, and using these thresholds in the validation cohort was associated with lower inappropriate empirical therapy, shorter hospitalization, and shorter total antibiotic treatment duration.

    What to keep in mind

    The abstract does not describe limitations in detail. The study was conducted in two tertiary centers and used a relatively small validation cohort, so the available summary does not show how broadly the findings apply beyond this setting.

    • EAS and VBS MRI scores were developed to distinguish pyogenic from tuberculous spondylitis.
    • Pyogenic spondylitis showed higher EAS and lower VBS scores than tuberculous spondylitis in both cohorts.
    • The derivation cohort identified EAS ≥ 0.400 and VBS ≤ 2.000 as optimal thresholds for pyogenic spondylitis.
    • Using the thresholds in validation was associated with less inappropriate empirical therapy, shorter hospital stays, and shorter antibiotic treatment duration.
    • CRP ≥ 50 mg/L was also reported as an independent predictor in both subgroup analyses.
  • Compensatory mutations showed limited effect on MDR/RR-TB clustering

    Compensatory mutations showed limited effect on MDR/RR-TB clustering

    What the study found

    The study found that compensatory mutations in multidrug-resistant and rifampicin-resistant tuberculosis (MDR/RR-TB) isolates had a limited contribution to transmission clustering in Hunan Province, China. The authors report no significant difference in clustering frequency or cluster size between strains with and without these mutations.

    Why the authors say this matters

    The authors conclude that compensatory mutations are not a major driver of community spread in this setting. They suggest that prolonged infectious periods linked to diagnostic delays and treatment challenges are more likely to sustain MDR/RR-TB transmission, supporting rapid detection, timely effective therapy, and robust patient management.

    What the researchers tested

    The researchers analyzed 206 non-duplicate MDR/RR-TB isolates collected from five surveillance sites in Hunan Province between 2013 and 2020. They used whole-genome sequencing, defined transmission clusters as isolates with 12 or fewer single-nucleotide polymorphism differences, and identified compensatory mutations in rpoA, rpoB, and rpoC using a curated mutation catalog and phylogenetic evidence.

    What worked and what didn't

    Among the 206 isolates, 63 (30.6%) carried at least one compensatory mutation, most often in rpoC, and 27 clusters were identified, ranging from 2 to 6 isolates. Clustering frequency did not differ significantly between compensated and non-compensated strains (21.7% vs 32.8%, P = 0.113), and cluster size did not differ significantly between C-type and N-type clusters (P = 0.961).

    What to keep in mind

    The summary describes a population-based study from one province in China, so the findings are specific to that setting and time period. M-type clusters were excluded to reduce confounding, and the abstract does not describe additional limitations.

    • The study examined 206 MDR/RR-TB isolates from five surveillance sites in Hunan Province, China.
    • 30.6% of isolates carried at least one compensatory mutation, mostly in rpoC.
    • Compensated and non-compensated strains did not differ significantly in clustering frequency.
    • Cluster size also did not differ significantly between C-type and N-type clusters.
    • The authors suggest delayed diagnosis and treatment challenges may be more important for transmission than compensatory mutations.