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The growth of acid-fast bacteria often hinders the detection of Legionella in water samples on agar plates by the plate culture method. We studied whether anti-tubercular agents inhibit acid-fast bacteria growth on agar plates. First, the antimicrobial activities of isoniazid, ethionamide, and ethambutol were evaluated against Mycobacterium and Legionella. We found that ethambutol at ≥ 100 μg/mL completely inhibited Mycobacterium growth, but ethambutol at 1,000 μg/mL did not inhibit Legionella growth. Next, the effect of ethambutol dissolved in acid buffer was examined. Cell suspensions of L. pneumophila and Mycobacterium spp. were mixed, and ethambutol-acid buffer was added. After 5 min, mixtures were inoculated on GVPC agar plates and incubated at 36℃ for 6 d. We found that ethambutol inhibited Mycobacterium growth on agar plates, but the Legionella colonies recovered. The effect of ethambutol was also significant in the evaluation using bathwaters. Comparing 1,302 bathwaters, the addition of ethambutol reduced the detection rate of acid-fast bacteria from 30.6% to 0% and increased the detection rate of Legionella from 7.1% to 7.5%. Ethambutol, which selectively inhibited acid-fast bacteria growth, enhanced the detection of Legionella on agar plates and will contribute to improving the accuracy of Legionella testing by the plate culture method.
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http://dx.doi.org/10.4265/jmc.29.1_1 | DOI Listing |
Medicine (Baltimore)
September 2025
Department of Tuberculosis, Guiyang Public Health Clinical Center, Guiyang, Guizhou Province, China.
Rationale: We report an extremely rare case in which delayed diagnosis and treatment of Mycobacterium tuberculosis infection primarily involving the subcutaneous tissues of an extremity led to hematogenous dissemination of the infection and subsequent deterioration of the patient.
Patient Concerns: An 82-year-old man presented to our hospital with a painful mass on the right ankle for over a year, as well as persistent fever and shortness of breath for >14 days. He received piperacillin/tazobactam followed by meropenem, which failed to decrease his peak temperature.
Vet Pathol
September 2025
Cornell University, Ithaca, NY.
Mycobacteria ( family) comprise five genera (, , , , and ), which include relevant animal and human pathogens. Histology is a rapid method for preemptively diagnosing mycobacteriosis, contributing to surveillance, control, and eradication. A constraint on histology is the limited sensitivity and specificity of acid-fast stains, as the number of detectable bacilli in formalin-fixed paraffin-embedded (FFPE) tissue varies and other microorganisms are acid-fast positive.
View Article and Find Full Text PDFMedicine (Baltimore)
August 2025
Department of Ultrasound, Kunming Medical University Affiliated Qujing Hospital, Qujing, China.
Rationale: Lawsonella clevelandensis is a gram-positive bacterium, partially acid-fast, strictly anaerobic, nonspore-forming, and catalase-positive. This microorganism was once overlooked in clinical microbiology due to its stringent growth requirements in laboratory cultures, but it has recently attracted recognition as a potential pathogen. Available reports implicate Lawsonella clevelandensis infection with abscess formation, including breast, spinal, abdominal, and deep soft tissue abscesses.
View Article and Find Full Text PDFDiagn Microbiol Infect Dis
December 2025
Department of Infectious Diseases and Tropical Medicine, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran.
Disseminated Mycobacterium avium complex (DMAC) infection is a major AIDS-defining condition with diagnostic challenges due to nonspecific symptoms. This study, for the first time in Iran, aimed to discriminate MAC organisms in 100 HIV-positive patients directly from clinical specimens and assess their clinical significance, epidemiological characteristics, and associated risk factors through a detailed review of medical and demographic records. Clinical specimens (blood, sputum, and stool) were collected, and routine clinical evaluations were performed.
View Article and Find Full Text PDFPathogens
August 2025
Radiology Department, Rush University Medical Group, Chicago, IL 60612, USA.
Tuberculosis (TB) is an ancient and re-emerging granulomatous infectious disease that continues to challenge public health. Early diagnosis and prompt effective treatment are crucial for preventing disease progression and reducing both morbidity and mortality. These steps play a vital role in infection control and in lowering death rates at both individual and population levels.
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