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Biomedical subjects

M Laverdiere

Publications and source records attributed to M Laverdiere.

At least 19 recordsLinked to original sources
PubMed2000

Comparative evaluation of the MB/BacT and BACTEC 460 TB systems for the detection of mycobacteria from clinical specimens: clinical relevance of higher recovery rates from broth-based detection systems.

New broth-based detection systems have higher recovery rates of mycobacteria from clinical specimens than traditional cultures on solid media. The clinical significance of this higher sensitivity rate is largely unknown. We prospectively evaluated the performances of two liquid media detection systems (the MB/BacT system and the BACTEC 460 TB system) and an egg-based Lowenstein-Gruft solid medium (LG) on the recovery rates of mycobacteria from 849 clinical specimens. Mycobacteria (other then M. gordonae) were detected in 51 (6.0%) specimens. In 12/51 (23%) specimens, mycobacteria (five mycobacterium tuberculosis (MtB) and seven non-M tuberculosis complex (MOTT) were recovered only from the broth-based systems. Review of the patients' clinical charts revealed that failure of LG to recover Mtb were due to nonmycobacterial overgrowth and antibiotic treatment. The recovered MOTT were all clinically nonsignificant. Higher sensitivity of broth-based mycobacteria detection systems is largely due to their capability to recover mycobacteria from treated tuberculous patients or from partially decontaminated specimens. The high recovery rates of nonclinically significant MOTT could potentially increase inappropriate use of antibiotics.

Bacterial Typing Techniques↗
PubMed1999

Randomized placebo-controlled trial of fluconazole prophylaxis for neutropenic cancer patients: benefit based on purpose and intensity of cytotoxic therapy. The Canadian Fluconazole Prophylaxis Study Group.

A randomized, double-blind trial comparing oral fluconazole (400 mg daily) with placebo as prophylaxis for adult patients receiving intensive cytotoxic therapy for acute leukemia or autologous bone marrow transplantation was conducted in 14 Canadian university-affiliated hospitals. Although fluconazole prophylaxis did not obviate the need for parenteral antifungal therapy compared with placebo (81 [57%] of 141 vs. 67 [50%] of 133, respectively), its use resulted in fewer superficial fungal infections (10 [7%] of 141 vs. 23 [18%] of 131, respectively; P = .02) and fewer definite and probable invasive fungal infections (9 vs. 32, respectively; P = .0001). Fluconazole recipients had fewer deaths attributable to definite invasive fungal infection (1 of 15 vs. 6 of 15, respectively; P = .04) and achieved more frequent success without fungal colonization (52 [37%] of 141 vs. 27 [20%] of 133, respectively; P = .004; relative risk reduction, 85%) than did placebo recipients. Patients benefiting the most from fluconazole prophylaxis included those with acute myeloid leukemia who were undergoing induction therapy with cytarabine plus anthracycline-based regimens and those receiving marrow autografts not supported with hematopoietic growth factors. Fluconazole prophylaxis reduces the incidence of superficial fungal infection and invasive fungal infection and fungal infection-related mortality among patients who are receiving intensive cytotoxic chemotherapy for remission induction.

Adolescent↗
PubMed1998

Comparative activity of trovafloxacin and Bay 12-8039 against 452 clinical isolates of Streptococcus pneumoniae.

The principal aim of this study was to evaluate the in-vitro activity of new quinolones against clinical strains of Streptococcus pneumoniae. Four hundred and fifty-two single clinical isolates (of which 362 were susceptible to penicillin, 54 intermediate and 36 highly resistant) were tested against penicillin, cefuroxime, ciprofloxacin, levofloxacin, trovafloxacin and Bay 12-8039. Of the tested S. pneumoniae strains, 97.1 % had MICs of trovafloxacin of < or = 0.25 mg/L, and 96.7% had MICs of Bay 12-8039 of < or = 0.25 mg/L (difference not statistically significant); 81.9% of strains had MICs of cefuroxime of < or = 0.25 mg/L (P < or = 0.001 against both quinolones). Only 4% and 0.7% of the strains had MICs of levofloxacin and ciprofloxacin respectively of < or = 0.25 mg/L. Compared with older quinolones, trovafloxacin and Bay 12-8039 have good in-vitro activity against S. pneumoniae.

Anti-Infective Agents↗
PubMed1996

A new urea broth-based test to detect Helicobacter pylori presence in upper gastrointestinal biopsies.

The aim of this study was to evaluate the performance of a simple and inexpensive homemade urea test (U-test) to detect Helicobacter pylori in upper digestive tract biopsies. We tested and compared the U-test with three other diagnostic methods: the Clo-test, and culture and pathology in 110 patients randomly chosen at the endoscopy clinic. When using culture and/or pathology as the "gold standard," H. pylori was found to exist in 54 patients. Pathology was positive in 50 cases (92.5%), culture in 49 (90.7%), the U-test in 45 (83.3%), and the Clo-test in 43 (79.6%). With regard to culture pathology, the sensitivities of the U-test and the Clo-test were 83.3% and 79.5%, respectively. Specificity was 100% for both methods. The kappa coefficient calculation between the U-test and the Clo-test was 0.98. The results show that the U-test is a reliable, fast, and inexpensive method for detecting H. pylori in upper gastrointestinal biopsies.

Adult↗
PubMed1993

Prospective randomized study of piperacillin/tazobactam therapy of surgically treated intra-abdominal infection. The Piperacillin/Tazobactam Intra-Abdominal Infection Study Group.

A randomized prospective trial was undertaken in adult patients with serious intra-abdominal infections to determine whether a new combination of antibiotic therapy could prove as efficacious as the combination that has been widely used in practice in the recent decade (clindamycin and gentamicin). Three hundred thirty-one patients were randomized in a 2:1 ratio, with the larger number of patients being treated parenterally with piperacillin and tazobactam. The results showed that both the clinical and microbiologic performance of the piperacillin/tazobactam combination was better than that of clindamycin and gentamicin. This clinical equivalence permits overall cost savings without compromising the existing quality of antimicrobial therapy for intra-abdominal infection.

Abdomen↗
PubMed1989

Severe bronchospasm followed by respiratory arrest during thallium-dipyridamole imaging.

We describe the occurrence of sudden severe bronchospasm and respiratory arrest following dipyridamole infusion in a patient with chronic obstructive pulmonary disease predominantly of the emphysematous type. The severe reaction was unexpected because the patient had tolerated well withdrawal of aminophylline derivatives for 48 hours and was receiving chronic prednisone 20 mg qd. Although the diagnostic and prognostic gains from dipyridamole imaging far outweigh the small risk associated with the test, patients with chronic pulmonary obstructive disease must be closely monitored during thallium-dipyridamole imaging.

Aged↗
PubMed1985

14q+ abnormality with probable t(8;14)(q24;q32) in a young Haitian immigrant with acquired immunodeficiency syndrome and concomitant Burkitt's-like lymphoma.

Cytogenetic analyses were carried out in a young Haitian immigrant with acquired immunodeficiency syndrome and concomitant Burkitt's-like lymphoma associated with massive bone marrow infiltration. A characteristic 14q+ abnormality was found in all bone marrow cells examined. Although chromosome abnormality involving band 8q24 was not evident in all the cells examined, some karyotypes show that the typical t(8;14)(q24;q32) is most probably present. No other complex rearrangements could be identified. This is the first report of concomitant acquired immunodeficiency syndrome and Burkitt's-like lymphoma in the Haitian community. Our cytogenetic findings provide further evidence for the role of specific chromosomal rearrangements in Burkitt's-like lymphoma oncogenesis in the setting of acquired immunodeficiency syndrome.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Brain abscess due to Petriellidium boydii.

A 22 year-old man died from multiple cerebral abscesses due to Petriellidium boydii 4 1/2 months after an episode of near drowning. The autopsy showed dissemination to heart and kidney. This patient had no immunocompromising disease but was treated with corticosteroids. The treatment of this condition with ventricular shunting and amphotericin B is discussed and compared with the experience of ten other cases reported in the literature.

Adult↗
PubMed1983

Outbreak of central-nervous-system toxoplasmosis in western Europe and North America.

Acute encephalitis caused by Toxoplasma gondii was diagnosed in ten patients in Belgium, the U.S.A., and Canada. None had underlying conditions usually associated with toxoplasmosis. Three had evidence of extraneural infection at necropsy. Nine patients died. Only two of the patients had a history of homosexuality, and one was a heroin addict. Five were Haitian, and four of them had lived in North America for 2-5 years. Eight of the patients had pronounced lymphopenia. Diagnosis of toxoplasmosis was hampered by a lack of suspicion that Toxoplasma could be the agent causing necrotising encephalitis in the non-immunocompromised host, the protean manifestations of the encephalitis, and a lack of a specific antibody response. The large number of cases appearing in western Europe and North America emphasise the necessity of including toxoplasmosis in the differential diagnosis of encephalitis of unknown aetiology.

Acute Disease↗
PubMed1983

Nephrogenic adenoma of the bladder after kidney transplantation: spontaneous improvement with azathioprine removal; surgical trauma and cytomegalovirus infection as possible etiologic factors.

We report 2 cases of nephrogenic adenoma several years after successful cadaver kidney transplantation. In 1 case the lesion had cytomegalovirus inclusions, and we observed a marked and sustained reduction in the extension of the lesion with cessation of azathioprine. Surgical trauma and cytomegalovirus infections are discussed as etiologic factors. Conservative treatment seemed appropriate.

Adenoma↗
PubMed1979

Endocarditis caused by coagulase-negative staphylococci.

Sixteen patients with coagulase-negative staphylococcal endocarditis were treated at the University of Minnesota Hospitals between January 1970 and September 1977. In six patients, endocarditis developed after prosthetic valve surgery; among the other ten patients (the medical group), eight had known antecedent valvular disease. The skin was thought to be the source of infection in eight patients, suggesting that prompt treatment of skin infections and avoidance of injections in patients with valvular disease are important measures in the prevention of this disease. Patients with prosthetic valve endocarditis were infected with antibiotic-resistant organisms and had a higher mortality than those in the medical group (83% versus 20%). Bacterial isolates from three patients with prosthetic valve endocarditis were resistant to methicillin, and two of these three isolates also were resistant to cephalothin by quantitative susceptibility testing. The only patient with prosthetic valve endocarditis to survive was operated upon early in the course of his illness. These observation, coupled with the high mortality in this series and in others, has prompted us to advocate early surgery in prosthetic valve endocarditis.

Adolescent↗
PubMed1978

In vitro activity of cephalosporins against methicillin-resistant, coagulase-negative staphylococci.

The in vitro activity of five cephalosporins, gentamicin, and vancomycin was determined against 41 clinical isolates of methicillin-resistant, coagulase-negative staphylococci. Results obtained with disk diffusion and agar dilution methods failed to show complete cross-resistance between methicillin and four of the five cephalosporins despite the use of a high-salt medium and a large inoculum. Thirty-six (88%) of the 41 isolates were sensitive to cephalothin by a standardized disk diffusion method, whereas 23 isolates (56%) were sensitive to cephalothin with use of an agar dilution method and a large inoculum. Of these 23 isolates, only 11 (47%) were both inhibited and killed by less than or equal to 6.25 microgram of cephalothin/ml. The inhibitory and bactericidal activity of gentamicin was greater than that of vancomycin and cephalothin. These results suggest that the disk diffusion technique has limitations in determining the in vitro activity of cephalosporins against methicillin-resistant, coagulase-negative staphylococci and that cephalothin exhibits poor bactericidal activity against these same isolates.

Cephalosporins↗
PubMed1978

Use of a heavy inoculum in the in vitro evaluation of the anti-staphylococcal activity of 19 cephalosporins.

The in vitro activity of 19 cephalosporins against 105 clinical isolates of Staphylococcus aureus and S. epidermidis was determined by using a heavy inoculum, i.e., 10(8) to 10(9) organisms per ml, to maximally challenge the antibiotics. The anti-staphylococcal activities of cephaloridine and 87/312 were consistently decreased by the use of a heavy inoculum when compared with the activity obtained with two less-concentrated inocula. The activity of most of the other compounds was also decreased with the use of a heavy inoculum, but this was observed only with selected isolates. Cephapirin, cephalothin, and cefazaflur were the most active drugs against the methicillin-susceptible isolates. Cephaloridine, cefamandole, cefazaflur, and 87/312 had substantial activity against methicillin-resistant staphylococci even with heavy inocula. With the exception of cefaclor against S. aureus, the orally absorbed cephalosporins were generally one-half to one-sixteenth as active as the parenterally administered cephalosporins. The median minimal inhibitory concentrations of five of the 12 parenteral cephalosporins were lower with the methicillin-susceptible S. aureus than with the methicillin-susceptible S. epidermidis strains.

Bacteriological Techniques↗
PubMed1978

Atrio-ventricular shuntinfections and endocarditis due to Staphylococcus epidermidis.

Two groups of patients (with endocarditis and with atrioventricular shunt infections due to Staphylococcus epidermidis) are presented together with analysis of the causative agents by bio- and phage-typing. Additionally phagocytic function of polymorphonuclear leukocytes of selected patients was investigated but no decreased phagocytic function was found. A possible way of treatment is discussed.

Cardiac Surgical Procedures↗