Anna Wanahita

Michael E. DeBakey VA Medical Center, Houston, Texas, United States

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Publications (10)63.08 Total impact

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    ABSTRACT: Evaluate the sensitivity and specificity of Indium(111)-labeled leukocyte scans as used in a general, tertiary care hospital. Retrospective review of electronic medical records from all patients who underwent Indium(111) scan at two large Veterans Affairs Medical Centers, 1999-2005, to determine congruence between Indium(111) scan readings and final clinical diagnoses, using all available data with at least 6 months of follow-up. Of 145 indium scans done for possible skeletal infection, infection was judged to be present in 52 cases. The sensitivity was 83%, and the specificity was 90%, with a diagnostic accuracy of 88%. Fifty-nine scans were done for indications other than skeletal infection. In 20 instances, when specific foci were suspected, the suspicion was correctly confirmed by indium scan in every case, without false positives or negatives (sensitivity and specificity, 100%). In 39 scans done to search for a possible source of nonspecific findings of infection (fever, leukocytosis, bacteremia), the sensitivity and specificity were 81% and 87%, respectively, with a diagnostic accuracy of 85%. Except as a means to confirm an already-suspected clinical focus, the indium scan appears to offer relatively little definitive information that can be used for diagnosis or treatment of infection.
    The Journal of infection 10/2007; 55(3):214-9. · 4.13 Impact Factor
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    ABSTRACT: Clostridium difficile colitis causes striking leukocytosis. We examined the possibility that toxins A or B, or other nontoxin products of C. difficile, act as superantigens, thereby stimulating leukocytosis. Our results failed to show major histocompatibility complex class II-dependent T lymphocyte proliferation, the hallmark of superantigen activity. Elevated white blood cell counts in C. difficile colitis are probably due to increased generation of cytokines such as interleukin-6 (IL-6) or IL-8.
    FEMS Immunology & Medical Microbiology 08/2006; 47(2):275-7. · 2.55 Impact Factor
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    ABSTRACT: In Kentucky, the incidence and mortality associated with stroke are among the highest in the United States. Treatment of modifiable risk factors can significantly prevent stroke. Identification of additional risk factors may further reduce stroke risk. Hypothyroidism is linked to altered lipid metabolism and is associated with hyperhomocysteinemia. In this study, we examined a possible association between acute ischemic stroke (AIS) and hypothyroidism. Records were reviewed on all consecutive patients admitted to the University of Louisville Stroke Center with a diagnosis of AIS or transient ischemic attack (TIA). Our data revealed that 12% of patients with AIS or TIA had hypothyroidism. A significant difference was found between the prevalence of hyperhomocysteinemia in patients with hypothyroidism (45.4%) compared with the prevalence of hyperhomocysteinemia in euthyroid patients (27.8%). Hypothyroidism is common in patients with AIS and TIA. Elevated homocysteine levels associated with hypothyroidism suggest that hypothyroidism may represent a modifiable stroke risk factor. Prospective studies are needed to verify this association.
    The Journal of the Kentucky Medical Association 06/2006; 104(5):191-3.
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    ABSTRACT: Clinicians continue to question the usefulness of microscopic examination of Gram-stained sputum specimens ("Gram staining") and sputum culture for diagnosis of pneumonia. We analyzed the sensitivity of these techniques in 105 patients with pneumococcal pneumonia proven by blood culture. Gram staining revealed gram-positive cocci in pairs and chains, and culture yielded pneumococci in only 31% and 44% of all cases, respectively. However, sputum specimens were never submitted for examination in 31 cases; in 16 others, the specimen was inadequate and a culture was not done. Excluding these cases, the sensitivities of Gram staining and culture were 57% and 79%, respectively. If patients receiving antibiotics for >24 h had been excluded, Gram staining would have suggested pneumococci in 63%, and culture results would have been positive in 86%. Sensitivity increased in inverse proportion to the duration of antibiotic therapy (P<.05). Microscopic examination of sputum samples before antibiotics were administered and performance of culture within 24 h of receipt of such treatment yielded the correct diagnosis in >80% of cases of pneumococcal pneumonia.
    Clinical Infectious Diseases 08/2004; 39(2):165-9. · 9.42 Impact Factor
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    ABSTRACT: To determine whether unrecognized Clostridium difficile infection is responsible for a substantial proportion of cases of unexplained leukocytosis in a tertiary care hospital setting. We prospectively identified 60 patients who had unexplained leukocytosis (white blood cell count > or =15,000/mm3). Fecal specimens were tested for C. difficile toxin using an enzyme immunosorbent assay. We compared the clinical features of patients who had positive or negative assay results, as well as of 26 hospitalized control patients who did not have unexplained leukocytosis. Thirty-five (58%) of the patients with unexplained leukocytosis had C. difficile toxin in at least one fecal specimen as compared with 3 (12%) of the controls (P <0.001). Symptoms of colitis were often mild or absent at the time the white blood cell count was first elevated or, if present, had not been recognized by the attending physicians. Leukocytosis resolved promptly in most patients who were treated with metronidazole. In the 25 patients (42%) who had a negative test for C. difficile toxin, leukocytosis also tended to resolve during empiric therapy with metronidazole; some of these patients may have had C. difficile infection. The majority of patients in our hospital who had unexplained leukocytosis had C. difficile infection. Unexplained leukocytosis in hospitalized patients should prompt a search for symptoms and signs consistent with C. difficile infection and a study to detect C. difficile. Empiric therapy with metronidazole may be effective in the appropriate epidemiologic setting.
    The American Journal of Medicine 11/2003; 115(7):543-6. · 5.30 Impact Factor
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    ABSTRACT: Few modern studies have enumerated the conditions associated with leukocytosis. Our clinical experience has implicated Clostridium difficile infection in a substantial proportion of patients with leukocytosis. In a prospective, observational study of 400 inpatients with WBC counts of >/=15,000 cells/mm(3), we documented >/=1 infection in 207 patients (53%). Of these 207 patients, 97 (47%) had pneumonia, 60 (29%) had urinary tract infection, 34 (16%) had soft-tissue infection, and 34 (16%) had C. difficile infection. C. difficile infection was present in 25% of patients with WBC counts of >30,000 cells/mm(3) who did not have hematological malignancy. Other causes of leukocytosis in the 400 patients included physiological stress, in 152 patients (38%); medications or drugs, in 42 (11%); hematological disease, in 22 (6%); and necrosis or inflammation, in 22 (6%). C. difficile infection is a prominent cause of leukocytosis and this diagnosis should be considered for patients with WBC counts of >/=15,000 cells/mm(3), even in the absence of diarrheal symptoms.
    Clinical Infectious Diseases 07/2002; 34(12):1585-92. · 9.42 Impact Factor
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    ABSTRACT: Because Streptococcus milleri group (SMG) bacteria--Streptococcus constellatus, Streptococcus intermedius, and Streptococcus anginosus--exhibit a striking propensity to cause abscesses, the interaction of these organisms with human polymorphonuclear leukocytes (PMNL) was examined. After incubation in pooled normal human serum, SMG stimulated less chemotaxis than did Staphylococcus aureus, in contrast to viridans streptococci, which caused greater chemotaxis than did S. aureus. PMNL ingested greater numbers of SMG and viridans streptococci than S. aureus but killed these organisms more slowly and less completely. Relative resistance to killing by PMNL is expected in organisms that cause abscesses, and inhibition of chemotaxis may contribute to pathogenicity, because delayed arrival of PMNL gives a head start to proliferating bacteria. This study helps explain the capacity of SMG to cause abscesses. It is unclear, however, why viridans streptococci, bacteria that rarely produce abscesses, share some of these same properties.
    The Journal of Infectious Diseases 02/2002; 185(1):85-90. · 5.78 Impact Factor
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    ABSTRACT: Previous studies of the antibiotic susceptibility of Streptococcus milleri group organisms have distinguished among species by using phenotypic techniques. Using 44 isolates that were speciated by 16S rRNA gene sequencing, we studied the MICs and minimum bactericidal concentrations of penicillin, ampicillin, ceftriaxone, and clindamycin for Streptococcus intermedius, Streptococcus constellatus, and Streptococcus anginosus. None of the organisms was resistant to beta-lactam antibiotics, although a few isolates were intermediately resistant; one strain of S. anginosus was tolerant to ampicillin, and another was tolerant to ceftriaxone. Six isolates were resistant to clindamycin, with representation from each of the three species. Relatively small differences in antibiotic susceptibilities among species of the S. milleri group show that speciation is unlikely to be important in selecting an antibiotic to treat infection caused by one of these isolates.
    Antimicrobial Agents and Chemotherapy 06/2001; 45(5):1511-4. · 4.45 Impact Factor
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    ABSTRACT: Recent surveys of physician practice have suggested the existence of excessive, inappropriate use of the fecal occult blood test (FOBT). We studied the implementation of this test in hospitalized patients. We performed a retrospective chart review of 1000 randomly selected patients who had been discharged from the Medicine service at four teaching hospitals. Patient demographics, clinical presentation, presence or absence of overt GI bleeding, and use of medications that might affect the FOBT were recorded. Reviewers assessed whether patients who had FOBT would have been candidates for colon resection if asymptomatic colon cancer had been found. Digital rectal examination was documented in 44.8% of patients; the findings were recorded in only 9%. A total of 421 patients had FOBT on admission, usually on stool obtained at digital rectal examination. Of the patients with a positive FOBT, 17% had active GI bleeding. Only 41.1% of patients with a positive FOBT were referred to the gastroenterology service. In 70.5% of patients, FOBT could be considered inappropriate because of factors such as age, active GI bleeding, or use of aspirin or other nonsteroidal anti-inflammatory drugs. The FOBT, which is validated only for colorectal cancer screening, is often performed inappropriately in patients admitted to the hospital. This test should be restricted in hospital practice. It would be preferable to identify patients who are appropriate candidates for colorectal cancer screening at the time of hospital discharge and to advise them about the appropriate performance of the FOBT at home.
    The American Journal of Gastroenterology 04/2001; · 9.21 Impact Factor
  • Gastroenterology 04/2000; 118(4). · 12.82 Impact Factor

Publication Stats

261 Citations
63.08 Total Impact Points


  • 2006–2007
    • Michael E. DeBakey VA Medical Center
      Houston, Texas, United States
  • 2002–2004
    • Baylor College of Medicine
      • • Section of Infectious Diseases
      • • Veterans Affairs Medical Center
      Houston, TX, United States
    • U.S. Department of Veterans Affairs
      Washington, Washington, D.C., United States