Hector Bonilla

Comparative in vitro activity of quinupristin/dalfopristin against multidrug resistant : Enterococcus faecium

The in vitro susceptibilities of 82 strains of vancomycin resistant Enterococcus faecium (VREF), (49 vanA and 33 vanB) from over 13 hospitals in Europe and United States were studied. The MIC for several antibiotics showed high levels of resistance to vancomycin, ampicillin, gentamicin, and imipenem. All VREF strains were highly susceptible to quinupristin/dalfopristin with a MIC 90% of 0.5 microgram/ml for both vanA and vanB phenotypes. Time-kill and synergy studies of VREF for quinupristin/dalfopristin alone and quinupristin/dalfopristin in combination with several antibiotics (ampicillin, gentamicin, ciprofloxacin, rifampin and novobiocin) did not show bactericidal activity. In induction experiments using SF6550, (VREF, a vanA strain), quinupristin/dalforpristin showed a delay in the expression of vancomycin resistance by 2.5 hours. The results of this study show quinupristin/dalfopristin to have excellent in vitro activity versus multiple resistant E. faecium.

Mycobacterium avium complex endocarditis: Spurious diagnosis resulting from laboratory cross contamination

Contamination between specimens within clinical microbiology laboratories may be responsible for spurious outbreaks of mycobacterial infections. We report the case of a patient who had culture-negative endocarditis and whose cardiac tissue obtained at surgery yielded Mycobacterium avium complex (MAC). Epidemiologic investigation suggested cross contamination probably occurred during processing of the sputum specimens of a patient with pulmonary MAC disease and the cardiac samples from our patient; molecular strain typing showed the isolates from both patients to be identical. When mycobacterial infection rates increase or an unexpected case of mycobacterial infection occurs, the clinician should be alert to the possibility of cross contamination in the laboratory as a possible explanation.

Does Staphylococcus aureus Bacteriuria Predict Clinical Outcomes in Patients With Bacteremia?: Analysis of 274 Patients With Staphylococcus aureus Blood Stream Infection

BackgroundStaphylococcus aureus bacteriuria is reported in 15% to 27% of patients with S. aureus bacteremia. Concomitant staphylococcal bacteremia and bacteriuria have been associated with increased risk of complications, intensive care unit admission, longer length of hospital stay, and higher mortality. MethodsA retrospective study was performed on patients with staphylococcal bacteremia who had urine culture done. Demographics, clinical presentation, microbiology, clinical outcomes, complications, and mortality were collected for patients with and without staphylococcal bacteriuria. ResultsOf 274 patients with staphylococcal bacteremia, 179 had urine culture performed. Staphylococcal bacteriuria was found in 20%. Patients with bacteriuria did not have significantly longer median length of hospital stay (10.5 vs. 11.0 days, P = 0.52), intensive care unit stay (2.5 vs. 1.0 days, P = 0.37), other complications, or 30- and 90-day mortality. There was no significant statistical difference between S. aureus bacteriuria caused by methicillin-resistant S. aureus and methicillin-sensitive S. aureus for any of the factors studied. On univariate analysis, patients with staphylococcal bacteriuria were more likely to have a malignancy (33.3% vs. 16.9%, P = 0.03) and septic embolic events (22.2% vs. 7.7%, P = 0.02) and less likely to have renal disease (13.9% vs. 32.9%, P = 0.04) than those without bacteriuria. ConclusionsConcomitant staphylococcal bacteremia and bacteriuria were not associated with increased mortality or worse clinical outcome.

Rheumatoid Arthritis, Vasculitis, and Mononeuritis Multiplex After BCG Used in a Patient With Bladder Carcinoma: Case Report and Review of the Literature

BackgroundThe incidence of patients with serious adverse effects after Bacille Calmette-Guerin (BCG) instillation for bladder cancer is approximately 0.5%. We report a patient with bladder cancer treated with BCG who subsequently developed rheumatoid arthritis associated with polyneuropathy and vasculitis. CaseA 55-year-old white man with bladder cancer was treated with instillation of BCG. After the third treatment, the patient developed symmetrical arthralgias and arthritis in the hands, feet, elbows, and knees associated with a burning sensation of the hands and soles bilaterally. An electromyogram nerve conduction study showed severe polyneuropathy. A muscle biopsy was compatible with vasculitis. Bacille Calmette-Guerin was discontinued, and the patient was started on isoniazid/vitamin B6, prednisone, and methotrexate. His symptoms resolved within 6 weeks of therapy. DiscussionBacille Calmette-Guerin is able to induce an autoimmune phenomenon through a mechanism of molecular mimicry. This hypothesis could explain the clinical manifestations and the presence of markers of autoimmunity seen in our patient. Monoclonal antibodies and clones of T cells derived from Mycobacterium tuberculosis against several human tissues have been found. We postulate that our patient’s positive rifampin, antinuclear antibodies and anti-cyclic citrullinated peptide antibodies by molecular mimicry to as well as the inflammatory response directed against BCG. ConclusionBacille Calmette-Guerin immunotherapy for bladder cancer can induce a clinical picture of rheumatoid arthritis associated with polyneuritis multiples and vasculitis.