Biomedical subjects
H F Bonilla
Publications and source records attributed to H F Bonilla.
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.
Colonization with vancomycin-resistant Enterococcus faecium: comparison of a long-term-care unit with an acute-care hospital.
OBJECTIVE: To compare the epidemiology of vancomycin-resistant Enterococcus faecium (VRE) in a long-term-care unit and an acute-care hospital. DESIGN: Point-prevalence surveys for VRE rectal colonization of patients were carried out over a 21-month period in patients in a long-term-care unit and an acute-care hospital (medical ward and intensive-care units). The environment and hands of healthcare workers also were sampled for VRE. Contour-clamped homogeneous electric field (CHEF) electrophoresis was used to evaluate possible transmission among roommates and the relatedness of patient strains to those in the environment and on the hands of healthcare workers. SETTING: A 200-bed Veterans Affairs Medical Center with an attached 90-bed long-term-care unit. RESULTS: From December 1994 to January 1996, rectal VRE colonization of patients in the long-term-care unit increased significantly from 9% to 22%. In contrast, patients on the medical ward rarely were colonized after the first survey in December 1994, and only two intensive-care-unit patients were found to be colonized during the four surveys. The environment was contaminated persistently in the long-term-care unit. In the four surveys, carriage of VRE on hands of healthcare workers varied from 13% to 41%; 65% of healthcare workers with VRE found on their hands worked in the long-term-care unit. Seven different strains were identified by CHEF typing. Although the initial survey found only vanA strains, subsequent surveys showed vanB strains also were present. CONCLUSIONS: Residents of a long-term-care unit frequently were colonized with VRE, but infections were uncommon in this population. The environment of the long-term-care unit was contaminated with VRE, and VRE was found frequently on the hands of healthcare workers in this unit. Both vanA and vanB genotypes were found in this setting.
Mycoplasma felis septic arthritis in a patient with hypogammaglobulinemia.
We describe the first documented case of Mycoplasma felis infection in a woman who had common variable immunodeficiency and who presented with septic arthritis of the left hip and right knee. M. felis was isolated from both joints. She had been exposed to cats before the diagnosis of M. felis septic arthritis was made. Both of the patient's joints were surgically debrided, and she was treated with doxycycline for several months. In spite of initial improvement, destruction of her hip was noted. Subsequently, she underwent hip arthroplasty; histopathological examination of the bone at the time of surgery showed chronic osteomyelitis, and doxycycline therapy was continued.
Opportunistic infections in patients with temporal arteritis treated with corticosteroids.
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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.
Susceptibility of ciprofloxacin-resistant staphylococci and enterococci to trovafloxacin.
The susceptibilities of clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and enterococci obtained over a 13-year period were tested for trovafloxacin, a new fluoroquinolone, and ciprofloxacin. For MRSA, MIC50 values for trovafloxacin increased from 0.03 microgram/ml to 1 microgram/ml from 1984-1985 to 1995-1996, but were lower than those noted for ciprofloxacin, which increased from 0.25 microgram/ml to > 8 micrograms/ml during the same period. Trovafloxacin also showed lower MIC50 values (0.12-0.25 microgram/ml) than ciprofloxacin (MIC50 of 0.5-1 microgram/ml) for E. faecalis isolates from 1985 through 1991, but against E. faecium and E. faecalis isolated in 1995-1996, the MIC50 values for both trovafloxacin and ciprofloxacin were 2 micrograms/ml and the MIC90 values were > or 8 micrograms/ml. Thus, cross-resistance between fluoroquinolones was shown for both enterococci and MRSA. Whether the greater intrinsic activity of trovafloxacin might allow its use in treating MRSA and enterococcal infections remains to be seen.
Long-term survival of vancomycin-resistant Enterococcus faecium on a contaminated surface.
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