Prenatal culture-based screening of Streptococcus agalactiae colonisation: resistance against erythromycin and clindamycin.
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Animals↗
Biomedical subjects
M Laverdière
Publications and source records attributed to M Laverdière.
What is the clinical significance of positive blood cultures with Aspergillus sp in hematopoietic stem cell transplant recipients? A 23 year experience.
Hematopoietic stem cell (HSC) transplantation is the most frequent underlying predisposing condition to invasive aspergillosis. However, the significance of positive blood culture with Aspergillus sp in this particular population remains uncertain. We retrospectively reviewed all blood cultures performed in 1453 patients who received HSC transplant at our institution between 1980 and 2002. We identified 19 patients with positive blood cultures with Aspergillus sp. Only one of these patients had clinical, histologic or microbiologic evidence of invasive aspergillosis. Thus, even in a population at highest risk for invasive aspergillosis, positive blood cultures with Aspergillus sp remain unusual, and cannot be readily associated with invasive aspergillosis. A case by case assessment by treating physicians of the clinical and radiologic parameters should be systematically made to establish the significance of aspergillemia. Single bottle positivity, obtained with the lysis-centrifugation blood culture system, is a common indicator of pseudoaspergillemia.
Adolescent↗
Development and evaluation of a PCR method for detection of the Clostridium difficile toxin B gene in stool specimens.
A PCR assay detecting Clostridium difficile toxin B gene in stool specimens was compared to the cytotoxicity assay as the reference standard for the diagnosis of C. difficile antibiotic-associated diarrhea (CDAD). Overall, 118 stool samples were tested. All of the specimens that were negative by the cytotoxicity assay (59 out of 118) were also negative by the PCR method (specificity of 100%). Of the 59 cytotoxin-positive samples, 54 were PCR positive (sensitivity of 91.5%). This PCR method is promising for rapid diagnosis of CDAD.
Animals↗
A nosocomial outbreak of fluoroquinolone-resistant Streptococcus pneumoniae.
Over the course of a 20-month period, in a hospital respiratory ward in which ciprofloxacin was often used as empirical antimicrobial therapy for lower respiratory tract infections (LRTIs), 16 patients with chronic bronchitis developed nosocomial LRTIs caused by penicillin- and ciprofloxacin-resistant Streptococcus pneumoniae (serotype 23 F). The minimum inhibitory concentration (MIC) of ciprofloxacin for all isolates from the first 9 patients was 4 microg/mL, in association with a parC mutation. Isolates from the subsequent 7 patients all had a ciprofloxacin MIC of 16 microg/mL, in association with an additional mutation in gyrA. The MICs for this isolate were 8 microg/mL of levofloxacin (resistant), 2 microg/mL of moxifloxacin and gatifloxacin (intermediately resistant), and 0.12 microg/mL of gemifloxacin. This outbreak demonstrates the ability of S. pneumoniae to acquire multiple mutations that result in increasing levels of resistance to the fluoroquinolones and to be transmitted from person to person.
Aged↗
Prevalence and antifungal susceptibility of 442 Candida isolates from blood and other normally sterile sites: results of a 2-year (1996 to 1998) multicenter surveillance study in Quebec, Canada.
During a 2-year surveillance program (1996 to 1998) in Quebec, Canada, 442 strains of Candida species were isolated from 415 patients in 51 hospitals. The distribution of species was as follows: Candida albicans, 54%; C. glabrata, 15%; C. parapsilosis, 12%; C. tropicalis, 9%; C. lusitaniae, 3%; C. krusei, 3%; and Candida spp., 3%. These data, compared to those of a 1985 survey, indicate variations in species distribution, with the proportions of C. glabrata and C. parapsilosis increasing by 9 and 4%, respectively, and those of C. albicans and C. tropicalis decreasing by 10 and 7%, respectively. However, these differences are statistically significant for C. glabrata and C. tropicalis only. MICs of amphotericin B were > or =4 microg/ml for 3% of isolates, all of which were non-C. albicans species. Three percent of C. albicans isolates were resistant to flucytosine (> or =32 microg/ml). Resistance to itraconazole (> or =1 microg/ml) and fluconazole (> or =64 microg/ml) was observed, respectively, in 1 and 1% of C. albicans, 14 and 9% of C. glabrata, 5 and 0% of C. tropicalis, and 0% of C. parapsilosis and C. lusitaniae isolates. Clinical data were obtained for 343 patients. The overall crude mortality rate was 38%, reflecting the multiple serious underlying illnesses found in these patients. Bloodstream infections were documented for 249 patients (73%). Overall, systemic triazoles had been administered to 10% of patients before the onset of candidiasis. The frequency of isolation of non-C. albicans species was significantly higher in this group of patients. Overall, only two C. albicans isolates were found to be resistant to fluconazole. These were obtained from an AIDS patient and a leukemia patient, both of whom had a history of previous exposure to fluconazole. At present, it appears that resistance to fluconazole in Quebec is rare and is restricted to patients with prior prolonged azole treatment.
Amphotericin B↗
Species-specific regulation of alternative splicing in the C-terminal region of the p53 tumor suppressor gene.
Alternative splicing occurs in the C-terminal region of the p53 tumor suppressor gene between two alternative 3' splice sites in intron 10. This alternative splicing event has been detected in murine cells, but not in rat or human tissues. In this paper, we have characterized the pattern of p53 alternative splicing in cell lines from five different species. Our results confirm that p53 alternative splicing is species-specific, being detected only in cell lines of rodent origin. Using transient transfection assays, we have established that the rat p53 gene undergoes efficient alternative splicing in both mouse and rat cell lines, thus demonstrating that it has all the necessary cis -acting sequences to be alternatively spliced. In contrast, we were unable to detect any usage of the human alternative 3' splice site under the same experimental conditions. Thus, the low levels or absence of alternatively spliced p53 mRNA in rat and human cell lines seems to be the result of different mechanisms. Our results support the hypothesis that there are species-specific mechanisms implicated in the regulation of p53 activity.
Alternative Splicing↗
Trichosporon beigelii funguria in renal transplant recipients.
Trichosporon beigelii funguria in renal transplant recipients is usually benign and is seldom associated with invasive or deep-seated infections.
Adult↗
Comparative activity of new quinolones against 326 clinical isolates of Stenotrophomonas maltophilia.
Stenotrophomonas maltophilia is an important emerging pathogen causing a variety of infections in severely ill patients. This microorganism is inherently resistant to many antibiotics, and only a few therapeutic options are available. The principal aim of this study was to assess the in vitro activity of new quinolones against this pathogen. Three hundred and twenty-six single clinical isolates were tested in this study. The MIC(90) was 16 mg/L for ciprofloxacin, 8 mg/L for levofloxacin and gatifloxacin, 4 mg/L for trovafloxacin, moxifloxacin and sparfloxacin and 2 mg/L for clinafloxacin. At a 2 mg/L concentration, a C(max) lung:MIC ratio of >/=10 can be reached for 95%, 84.3%, 83.1% and 81.5% of isolates, respectively, for clinafloxacin, trovafloxacin, moxifloxacin and sparfloxacin (P < 0. 001 compared with levofloxacin and ciprofloxacin). In spite of the rare but serious adverse events associated with the new-generation quinolones, these agents may become very useful in the treatment of certain severe or life-threatening infectious conditions due to S. maltophilia, notably lower respiratory tract infections.
4-Quinolones↗
Impact of fluconazole prophylaxis on fungal colonization and infection rates in neutropenic patients. The Canadian Fluconazole Study.
Fungal colonization profiles from four different anatomical sites were evaluated in 266 neutropenic cancer patients receiving intensive cytotoxic therapy for acute leukaemia or for autologous marrow transplantation. At the beginning of chemotherapy patients were allocated randomly to receive oral fluconazole 400 mg daily or an identical placebo until prophylaxis failure or marrow recovery. Candida albicans colonization was reduced from 30 to 10% in the fluconazole recipients while it increased from 32 to 57% in the placebo patients (P<0.001). By the end of prophylaxis, colonization with non-albicans Candida species increased from 7 to 21% and 8 to 18% in the fluconazole and placebo patients, respectively (P = 0.396). Although Candida glabrata was isolated more frequently at the end of the prophylactic period in the fluconazole patients than in the placebo patients (16 versus 7%), only one definite invasive C. glabrata infection was noted. Overall, definite invasive fungal infections were documented in 26 patients [four fluconazole versus 22 placebo patients (P< or =0.001)]. In 23 (92%) patients the infections were caused by persistently colonizing or newly acquired organisms. While probable invasive fungal infections were noted in five fluconazole patients, 10 placebo patients were also affected (P = 0.19). An end-of-prophylaxis colonization index >0.25 was 76% sensitive but only 69% specific for invasive fungal infection. However, a colonization index < or =0.25 at baseline had a negative predictive value of 88% for development of invasive fungal infection. Fluconazole prophylaxis decreased colonization by fungi and subsequent invasive fungal infections in neutropenic cancer patients.
Adolescent↗
Group A Streptococcus carriage among close contacts of patients with invasive infections.
During the past few years, the incidence of invasive group A Streptococcus (GAS) infection has been increasing. However, there are presently no clear recommendations regarding antibiotic prophylaxis for close contacts of index patients. The aims of this study were 1) to determine the prevalence of carriage of the same GAS strain as the patient's among contacts of patients with invasive infections and 2) to assess the importance of exposure duration. From March 1995 to March 1996, the authors prospectively included in the study all patients with invasive GAS infection, as defined by the Working Group on Severe Streptococcal Infections, who came to Hôpital Maisonneuve-Rosemont in Montreal, Quebec, Canada. An epidemiologic investigation was systematically carried out for each index case. Contacts were divided into two groups: those who had spent 24 hours or more with the index patient during the week preceding the beginning of his or her illness and those who had spent 12-24 hours with the index patient during that week. Strains of GAS were examined by serotyping (proteins M and T and the presence or absence of the serum opacity factor) and by characterization of streptococcal pyrogenic exotoxins (exotoxins A, B, and C). One hundred and two contacts of 17 index cases with invasive GAS infection were systematically screened. Contacts were considered positive if they carried the same strain of the bacterium and the same streptococcal pyrogenic exotoxin as the index case. Among the contacts who had spent at least 24 hours per week with their respective index cases, 13 out of 48 (27%) were found to be harboring the same serotype of GAS as the index patient (95% confidence interval 14.5-39.5). By comparison, only one of the 54 contacts in the 12- to 24-hour group (1.8%) was found to be carrying the same strain of the bacterium (95% confidence interval 0-5.3). This difference between the two groups was statistically significant (p<0.001). The median age of the positive carriers (10 years) was significantly lower than the median age of the noncarriers (39 years) (p< or =0.0005). This study showed that close contacts who had spent 12-24 hours with the index patient were rarely colonized with GAS. If antibiotic prophylaxis against GAS is recommended, it should probably target contacts who spent at least 24 hours with an infected patient during the week preceding illness onset.
Adolescent↗
Varicella-zoster screening and management programs in healthcare facilities in Canada.
A 24-question survey on varicella-zoster screening programs and control measures for varicella-zoster infections was sent to 170 Canadian healthcare facilities. The results indicated that 60% of Canadian healthcare facilities have well-established preemployment varicella-zoster screening programs for healthcare workers. Overall, 30% of healthcare facilities impose work restrictions for susceptible healthcare workers, 49% use negative-pressure rooms for varicella-zoster management, and 28% have a policy to discharge susceptible exposed patients. Large variations exist among Canadian healthcare facilities in their varicella-zoster infection control policies.
Canada↗
Simple strategy for direct identification of medically important yeast species from positive blood culture vials.
We compared direct inoculation of the Auxacolor yeast identification system from positive blood culture vials to standard identification with the API 20C AUX (API 20C), using 44 prospectively collected clinical specimens and 25 seeded blood culture vials. Direct inoculation of the Auxacolor system was accurate and more rapid than standard identification with the API 20C.
Blood↗
Primary renal mucormycosis.
Primary renal mucormycosis is a rare infection capable of acute illness with sepsis. Few cases have been reported. We report a case of an acute primary renal mucormycosis and review the published reports. The incidence of primary renal mucormycosis has risen in recent years. The most frequently reported underlying predisposing disorders are human immunodeficiency virus infection, intravenous drug abuse, and diabetes mellitus. Primary renal mucormycosis should be suspected in patients with an immunocompromising illness or particular risk factors, when persistent flank pain and fever with sterile urine not responding to appropriate antibiotics are associated with enlarged heterogeneous kidneys.
Acute Disease↗
Trends in antibiotic resistance of staphylococci over an eight-year period: differences in the emergence of resistance between coagulase positive and coagulase-negative staphylococci.
The antimicrobial susceptibilities of 1058 Staphylococcus aureus and 2,163 coagulase-negative staphylococci (CNS) isolates obtained from clinical specimen between 1988 and 1995, were determined against 13 anti-staphylococcal antibiotics. During the study period the resistance of Staphylococcus aureus to ciprofloxacin, ceftazidime, and norfloxacin increased significantly by 7%, 4%, and 6%, respectively (p < or = 0.001). By comparison, the antibiotic resistance of CNS to ceftazidime, oxacillin, norfloxacin, ciprofloxacin, fusidic acid, and cefoxitin increased by 20%, 17%, 15%, 14%, 12% and 10%, respectively (p < or = 0.001). Invasive and noninvasive S. aureus had similar antibiotic resistance, whereas CNS invasive isolates were more resistant than noninvasive isolates to every antibiotics, except vancomycin and fusidic acid. These differences were significant (p < 0.001) for oxacillin, cefoxitin, and clindamycin. Our observations confirm that staphylococci and particularly CNS isolates show an important rate of increased resistance to the standard antimicrobials used for therapy, and that the rate of emergence of resistance differ considerably between coagulase-positive and coagulase-negative staphylococci.
Anti-Bacterial Agents↗
Comparison of activity of 10 antibiotics against clinical strains of Helicobacter pylori by three different techniques.
The authors determined the susceptibility of 55 single clinical strains of Helicobacter pylori isolated in the Montreal area to 10 antibiotics by three different methods--an agar dilution technique considered to be the gold standard, a disk diffusion method and the E-test. Testing was performed on Mueller-Hinton agar supplemented with 10% sheep blood; plates were incubated at 37 degrees C for 72 h in a microaerophilic atmosphere. The metronidazole resistance rate is about 11% in the Montreal area. Macrolides are very active against H pylori isolates, with few variations in activity between older and newer molecules. Correlation among different methods was not as good as reported in the literature for metronidazole.
Anti-Bacterial Agents↗
Poor immediate tolerability of amphotericin B lipid emulsion in patients with haematological malignancies. Haematology-Microbiology Group.
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Amphotericin B↗
Group A Streptococcus invasive infections: a review.
The incidence of group A Streptococcus (GAS) invasive infections has been increasing worldwide, and there is no obvious explanation for this phenomenon. In 1993, a working group on severe GAS infections was established to define accurately what constitutes an invasive infection. Three types of infection are particularly feared: necrotizing fasciitis, myositis and a newly defined entity, named streptococcal toxic shock syndrome (STSS) because of a certain analogy with its staphylococcal counterpart. GAS produces many toxins responsible for its clinical manifestations. Some of them, labelled streptococcal pyrogenic exotoxins, have been characterized as superantigens. These proteins play a key role in initiating the immune response to GAS and are mostly responsible for the precipitous course of invasive infections. Death rates are high in streptococcal invasive infections, ranging from about 20% for necrotizing fasciitis to almost 100% for myositis. Therapy consists mainly of high doses of antibiotic combinations, aggressive surgery, and intravenous administration of immunoglobulins for STSS.
Adult↗
Corynebacterium striatum meningitis: case report and review of an increasingly important Corynebacterium species.
For a long time, corynebacteria were considered simple cutaneous contaminants with little potential pathogenicity. Corynebacterium striatum is a known saprophytic cutaneous bacterium; however, in the last decade, this organism has been increasingly recognized as a pathogen. It has been mostly implicated in respiratory tract and blood infections. To our knowledge, we report the first case of meningitis due to C. striatum. Treatment with intravenous vancomycin resulted in therapeutic success. We also thoroughly review all previously reported cases of C. striatum infection. Identification of Corynebacterium species can be difficult because of rapid taxonomic changes, and susceptibility testing for these microorganisms is not yet standardized. However, because of their growing clinical importance, data on these bacteria are accumulating.
Adult↗