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Volume 8, Number 11—November 2002
THEME ISSUE
Tuberculosis Genotyping
Tuberculosis Genotyping Network, United States

A Prospective, Multicenter Study of Laboratory Cross-Contamination of Mycobacterium tuberculosis Cultures

Robert M. Jasmer*Comments to Author , Marguerite Roemer†, John Hamilton‡, John Bunter§, Christopher R. Braden¶, Thomas M. Shinnick¶, and Edward P. Desmond**
Author affiliations: *San Francisco General Hospital Medical Center and University of California, San Francisco, California, USA; †San Francisco General Hospital, San Francisco, California, USA; ‡Santa Clara Valley Medical Center, San Jose, California, USA; §Solano County Public Health Laboratory, Vallejo, California, USA; ¶Centers for Disease Control and Prevention, Atlanta, Georgia, USA; **California Department of Health Services, Berkeley, California, USA;

Main Article

Table

Clinical and laboratory characteristics of patients suspected of having false-positive cultures for Mycobacterium tuberculosisa

Patient Lab Specimen
type Initial or follow-up specimen Sputum smear result Clinical signs and symptoms Comments Panel decision Final diagnosis
1 1 Sputum Initial Negative 36-yr-old man with AIDS hospitalized with cough, dyspnea, right lower lobe infiltrate; he improved with trimethoprim and sulfamethoxazole alone Genotype of isolate matched that of another patient whose specimen was processed same day Cross-contamination Bacterial pneumonia
2 2 Sputum Initial 2+ Positive 28-yr-old man with HIV infection with fever, cough, right lower lobe infiltrate; improved with ceftazidime Genotype of isolate matched that of another patient hospitalized on the same ward Mislabeled specimen Bacterial pneumonia
3 2 Sputum Initial Negative 31-yr-old woman hospitalized with cough, left lower lobe infiltrate, and leukocytosis; chest radiograph showed improvement with clindamycin and ofloxacin Genotype of isolate matched that of another patient whose specimen was processed same day Cross-contamination Bacterial pneumonia
4 2 Sputum Initial Negative 44-yr-old man hospitalized with cough and right lower lobe infiltrate; improved with levofloxacin before anti-TB therapy initiated Genotype of isolate matched that of another patient whose specimen in the BACTEC instrument immediately preceded the case patient Cross-contamination Lung abscess
5 2 Sputum Follow-up Negative 68-yr-old woman newly immigrated from China with cough; chest radiograph showed bi-apical fibronodular changes Genotype of second isolate >30 days later did not match that of initial isolate or any other isolate in database Mislabeled specimen or mixed infection Bacterial pneumonia versus TB with mixed infection]
6 2 Sputum Initial 4+ Positive 82-yr-old man with cough, fever; chest radiograph showed chronically increased right mid-lung interstitial markings Genotype of isolate matched that of another patient hospitalized on the same ward Mislabeled specimen or cross-contamination Bacterial pneumonia
7 2 Sputum Initial Negative 27-yr-old woman with upper respiratory symptoms; chest radiograph was normal Genotype of isolate matched that of another patient whose specimen was processed same day Cross-contamination Upper respiratory tract infection
8 2 Sputum Initial Negative 44-yr-old man with hemoptysis and known pulmonary metastases of squamous cell carcinoma of trachea; chest radiograph showed three large cavities with air-fluid levels; bronchoscopy culture grew H. influenzae, and patient improved on antibiotics alone Genotype of isolate matched that of another patient whose specimen was processed same day Cross-contamination Lung abscess
9 2 Broncho-alveloar lavage Initial Negative 55-yr-old woman hospitalized with dyspnea and left lower lobe infiltrate; she improved with broad-spectrum antibiotics alone Genotype of isolate matched that of another patient whose specimen was processed same day Cross-contamination Bacterial pneumonia
10 3 Sputum Follow-up Negative 34-yr-old homeless man with HIV infection, fever, and cervical lymphadenopathy; chest radiograph showed left lung nodule Genotype of initial isolate matched that of another homeless TB patient; follow-up specimen (35 days later) had a unique genotype TB TB

aLab, laboratory; TB, tuberculosis; H. influenzae, Haemophilus influenzae.

Main Article

Page created: July 19, 2010
Page updated: July 19, 2010
Page reviewed: July 19, 2010
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
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