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Die Multiplex PCR Technologie hält in der mikrobiologischen Diagnostik mehr und mehr Einzug. Diese Technik erlaubt in einem einzigen Probenlauf die simultane Amplifikation von mehreren DNA/RNA-Zielsequenzen von Erregern über die Speziesebene hinaus. Verschiedene Erreger von Infektionskrankheiten können durch einen Symptom-orientierten Approach eindeutig und rasch mit hoher Zuverlässigkeit nachgewiesen werden. Im Wesentlichen verfügt man heute über Multiplex PCR-Panels zur Abklärung von gastrointestinalen, respiratorischen, urogenitalen Infekten, sowie zur Meningitis-Diagnostik. Das heutige Angebot der Industrie, der Universitätsspitäler und der größeren Privatlabors der Schweiz wird tabellarisch dargestellt und kommentiert.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is an escalating problem in hospitals worldwide. The hospital reservoir for MRSA includes recognized and unrecognized colonized or infected patients, as well as previously colonized or infected patients readmitted to the hospital. Early and appropriate infection control measures (ICM) are key elements to reduce MRSA transmission and to control the hospital reservoir.Objective: To describe the role of an expert system applied to the control of MRSA at a large medical center (1,600 beds) with high endemic rates.Methods: The University Hospital of Geneva has an extended hospital information system (HIS), DIOGENE, structured with an open distributed architecture. It includes administrative, medical, nursing, and laboratory applications with their relational databases. Among available patient databases, clinical microbiology laboratory and admission-discharge-transfer (ADT) databases are used to generate computer alerts. A laboratory alert (lab alert) is printed daily in the Infection Control Program (ICP) offices, listing all patients with cultures positive for MRSA detected within the preceding 24 hours. Patients might be either newly detected patients colonized or infected with MRSA, or previously recognized MRSA patients having surveillance cultures. The ICP nurses subsequently go to the ward or call the ward personnel to implement ICM. A second alert, the “readmission alert,” detects readmission to the hospital of any patient previously colonized or infected with MRSA by periodic queries (q 1 min) to the ADT database. The readmission alert is printed in the ICP offices, but also forwarded with added guidelines to the emergency room.Results: During the first 12 months of application (July 1994 to June 1995), the lab alert detected an average of 4.6 isolates per day, corresponding to 314 hospital admissions (248 patients); the use of this alert saved time for the ICP nurses by improving work organization. There were 438 readmission alerts (1.2 alerts per day) over the study period; of 347 patients screened immediately upon readmission, 114 (33%) were positive for MRSA carriage. Delayed recognition of readmitted MRSA carriers decreased significantly after the implementation of this alert; the proportion of MRSA patients recognized at the time of admission to the hospital increased from 13% in 1993 to 40% in 1995 (PConclusions: Hospital information system-based alerts can play an important role in the surveillance and early prevention of MRSA transmission, and it can help to recognize patterns of colonization and transmission.

Bacterial adherence to polymer surfaces is a required early step in intravenous (iv) device infection. We collected eight strains of Staphylococcus aureus and 19 of coagulase-negative staphylococci from patients with proven iv device bacteremia and studied the role of plasma or connective-tissue proteins in promoting bacterial adherence to polymethylmethacrylate (PMMA) coverslips. Although only a negligible percentage of organisms adhered to albumin-coated PMMA, surface-bound fibronectin significantly promoted adherence of all isolates. Fibrinogen markedly promoted adherence of all S. aureus strains but of only four coagulase-negative strains. Thus, coagulase-negative staphylococci revealed a marked heterogeneity in adherence to fibrinogen-coated surfaces, a result suggesting the existence of heretofore unknown receptors for fibrinogen. Laminin promoted adherence of staphylococci to a much lower extent. Although strain specific, adherence of clinical staphylococcal isolates to foreign surfaces is significantly increased by fibronectin, fibrinogen, and laminin, an observation suggesting the possible contribution of these proteins to the pathogenesis of iv device infection.

In a prospective, randomized trial, teicoplanin (at a 400-mg intravenous loading dose followed by 200 mg/day intravenously or intramuscularly) was compared with flucloxacillin (8 g/day) in patients with severe staphylococcal infections. Teicoplanin proved unsatisfactory for the following reasons: (1) failures or relapses were more frequent in the teicoplanin group, and (2) blood levels were difficult to predict and tended to be low 24 hr after the loading dose. Future trials with this agent should use much-higher doses

Because persistence of infections associated with prosthetic material despite the use of appropriate antibiotics is a major clinical problem, the antimicrobial susceptibility of bacteria responsible for a chronic subcutaneous tissue cage infection in rat was investigated ex vivo. Three to 6 weeks after the initiation of infection, suspensions of two strains of Staphylococcus aureus recovered from the foreign body surface and surrounding fluid were exposed to either oxacillin, vancomycin, fleroxacin, gentamicin, or rifampin. The MBCs of these bacteria were markedly elevated, in most cases 128 to greater than 256 times higher than the MBC of batch culture S. aureus in either logarithmic or stationary phase. Kinetic studies showed the bacteria did not grow when incubated for 2 h in Mueller-Hinton broth, possibly reflecting dormancy. Their killing was slow and incomplete by all antibiotics at greater than 8 times their MIC. These data provide direct evidence of a decreased susceptibility of S. aureus to the killing effect of antimicrobials during chronic foreign body infections in vivo.

Multiplex PCR technologies progressively find their way in clinical microbiology. This technique allows the simultaneous amplification of multiple DNA targets in a single test run for the identification of pathogens up to the species level. Various pathogens of infectious diseases can be detected by a symptom-oriented approach clearly and quickly with high reliability. Essentially multiplex PCR panels are available for clarification of gastrointestinal, respiratory, sexually transmitted infections and meningitis. Today's offer from industry, university hospitals and large private laboratories of Switzerland is tabulated and commented.Die Multiplex PCR Technologie hält in der mikrobiologischen Diagnostik mehr und mehr Einzug. Diese Technik erlaubt in einem einzigen Probenlauf die simultane Amplifikation von mehreren DNA/RNA-Zielsequenzen von Erregern über die Speziesebene hinaus. Verschiedene Erreger von Infektionskrankheiten können durch einen Symptom-orientierten Approach eindeutig und rasch mit hoher Zuverlässigkeit nachgewiesen werden. Im Wesentlichen verfügt man heute über Multiplex PCR-Panels zur Abklärung von gastrointestinalen, respiratorischen, urogenitalen Infekten, sowie zur Meningitis-Diagnostik. Das heutige Angebot der Industrie, der Universitätsspitäler und der größeren Privatlabors der Schweiz wird tabellarisch dargestellt und kommentiert.

Among 10 strains of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) isolated in 2002 from patients with skin infections, seven harbored the Panton-Valentine leukocidin gene, two harbored the exfoliative toxin A gene, and one harbored neither of these genes. CA-MRSA isolates producing a variety of exotoxins are currently spreading in the Swiss community.

Objective. Infections caused by Candida spp. are a major cause of morbidity and mortality in critically ill patients and usually develop from endogenous colonization. We assessed the effectiveness of adding fluconazole to a selective digestive decontamination regimen to prevent candidal infections. Design and setting. We performed a prospective, randomized, double-blind, placebo-controlled trial among medical and surgical intensive care unit patients at a large university hospital. Patients. All adult patients mechanically ventilated for at least 48 h with an expectation to remain so for at least an additional 72 h, and receiving selective decontamination of the digestive tract. Interventions. Patients were randomly assigned fluconazole 100 mg daily (n=103) or placebo (n=101). Measurements and results. Candida infections occurred less frequently in the fluconazole group (5.8%) than in the placebo group (16%; rate ratio 0.35; Cl95 0.11–0.94). Some 90% of candidemia episodes occurred in the placebo group (rate ratio for fluconazole use 0.10; Cl95 0.02–0.74). The rate of treatment failure, development of candidal infection, or increased colonization, was 32% in the fluconazole group and 67% in the placebo group (P

Pharmacokinetic and pharmacodynamic parameters are increasingly recognized as important determinants of the therapeutic efficacy of an antibiotic. For β-lactam antibiotics, the most important determinant of the antimicrobial efficacy, and hence predictor of therapeutic efficacy, is the length of time that serum concentrations exceed the MIC. Dosing schedules for β-lactam antibiotics should maintain serum concentrations above the MIC for the bacterial pathogen for at least 50% of the dosing interval to achieve therapeutic efficacy and prevent the development of resistance. This is a basic criterion for the clinical efficacy of β-lactams. A combination of microbiological activity and pharmacokinetic characteristics was applied to calculate the time that serum antibiotic concentrations exceed the MIC for the major respiratory tract pathogens such as Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pyogenes and Klebsiella pneumoniae . In contrast with some other oral β-lactam antibiotics, cefpodoxime 200 mg bd maintains serum concentrations above the MIC for each organism for at least 50% of the dosing interval and may therefore be an attractive choice for empirical therapy of community-acquired lower respiratory tract infections.

All patients positive for methicillin-resistant Staphylococcus aureus (MRSA) at the University Hospitals of Geneva, Switzerland, between 1989 and 1997 (N = 1771) were included in a cohort study to evaluate the consequences of delayed containment of a hospital-wide outbreak occurring during a 4-year absence of MRSA control measures. The effects of efforts to control both the MRSA reservoir and the number of bacteraemic patients were assessed. Intensive infection control measures were initiated in 1993 and included patient screening, on-site surveillance, contact isolation, a computerized alert system, and hospital-wide promotion of hand hygiene. An increase in the rate of new MRSA-infected or -colonized patients was observed between 1989 and 1994 (from 0.05 to 0.60 cases per 100 admissions), which subsequently decreased to 0.24 cases in 1997 (P

ObjectiveTo identify at species level, in a prospective study in a tertiary university hospital during the two years 1996 and 1997, all isolates of Campylobacter spp. and related organisms and to determine their susceptibility to erythromycin and ciprofloxacin.MethodsThe feces were collected in Cary–Blair medium, and isolation was performed on Karmali agar incubated at 35°C. BACTEC Plus aerobic/F vials were used for blood cultures. Identification was performed by biochemical methods for Campylobacter jejuni and by molecular hybridization for the other species. MICs for erythromycin and ciprofloxacin were determined by Etest.Resultsin total, 142 isolates from 140 infected patients, including 135 fecal isolates and seven blood isolates, were analyzed. Clinical findings of the seven patients with bacteremia and the seven patients with gastroenteritis due to species other than Campylobacter jejuni or Campylobacter coli showed a predominance of immunocompromised patients. The fecal isolates include 113 (83.7%) Campylobacter jejuni, nine (6.6%) Campylobacter coli, four Arcobacter butzleri, two Campylobacter fetus and one Helicobacter pullorum. Of the seven isolates from blood culture, three were Campylobacter jejuni, three Campylobacter fetus and one Helicobacter cinaedi. Resistance to ciprofloxacin (MIC ≥4 mg/L) was reported for 18 (15.6%) Campylobacter jejuni isolates, three Campylobacter coli isolates, one Campylobacter fetus isolate and one Arcobacter butzleri isolate. Resistance to erythromycin (MIC ≥8 mg/L) was found for two isolates of Campylobacter coli, which were also resistant to ciprofloxacin, and the isolate of Helicobacter cinaedi.ConclusionsThis study reports a predominance of Campylobacter jejuni from stools, but a variety of more rarely isolated species was found in immunocompromised patients, emphasizing the necessity to identify fecal as well as blood isolates to the species level. Antimicrobial susceptibility tests to major antibiotics active against campylobacteria should be done routinely to follow the rate of resistance.

Objective To reassess the relative potencies of teicoplanin and vancomycin following several years of clinical usage. Methods The glycopeptide susceptibilities of clinical isolates of staphylococci collected from 70 hospitals in 1995 were determined using NCCLS (National Committee for Clinical Laboratory Standards) methods. Results In total, 2885 isolates of Staphylococcus aureus and 1480 isolates of coagulase-negative staphylococci were collected. S. aureus was significantly less susceptible to vancomycin (MIC 50 1 mg/L) than teicoplanin (MIC 50 0.5 mg/L), but the reverse was the case for S. haemolyticus and S. epidermidis. No S. aureus isolate was resistant (≥32 mg/L) to either glycopeptide, but nine isolates of coagulase-negative staphylococci had an MIC of teicoplanin of 32 mg/L. Respiratory isolates of S. aureus were less susceptible to glycopeptides than those from other sites. Staphylococci from Belgium and Italy were less susceptible to teicoplanin than isolates from other countries. Conclusions This European survey shows that in 10 years of clinical use there have been no major changes in the susceptibility of staphylococci to the glycopeptides.

Mupirocin has been widely used for the clearance of nasal methicillin-resistant Staphylococcus aureus (MRSA) carriage during outbreaks, but no placebo-controlled trial has evaluated its value for eradicating MRSA carriage at multiple body sites in settings where MRSA is not epidemic. In a 1,500-bed teaching hospital with endemic MRSA, 102 patients colonized with MRSA were randomized into a double-blind, placebo-controlled trial and treated with either mupirocin (group M) or placebo (group P) applied to the anterior nares for 5 days; both groups used chlorhexidine soap for body washing. Follow-up screening, susceptibility testing, and genotyping were performed to evaluate treatment success, mupirocin or chlorhexidine resistance, and exogenous recolonization. At baseline, MRSA carriage was 60% in the nares, 38% in the groin, and 62% in other sites (skin lesions, urine). The MRSA eradication rate (all body sites) was 25% in group M (12 of 48 patients), compared to 18% in group P (9 of 50 patients; relative risk [RR], 0.72; 95% confidence interval [CI 95 ], 0.33 to 1.55). At the end of follow-up, 44% of patients (19 of 43) were free of nasal MRSA in group M, compared to 23% (11 of 44) in group P (RR, 0.57; CI 95 , 0.31 to 1.04). Ten patients developed MRSA infections (three in group M and seven in group P). One mupirocin treatment failure was due to exogenous MRSA recolonization. No MRSA isolate showed chlorhexidine resistance or high-level mupirocin resistance; however, we observed an association ( P = 0.003) between low-level mupirocin resistance at study entry (prevalence, 23%) and subsequent treatment failure in both study arms. These results suggest that nasal mupirocin is only marginally effective in the eradication of multisite MRSA carriage in a setting where MRSA is endemic.

In order to characterize the impact and pattern of Gram-negative bacteraemia (GNB) at a Swiss University hospital and to assess the effect of multi-resistance on mortality, we conducted a 6-y retrospective cohort study using linear regression and multivariate Cox-proportional hazard analysis. 1766 patients had 1835 episodes of GNB; 61% were community-acquired. The incidence of GNB increased linearly (r2 = 0.90, p = 0.014) from 7.07 episodes to 8.32 episodes per 1000 admissions, but this trend was no longer significant after adjustment for the number of blood cultures drawn/y. The in-hospital mortality for patients with GNB decreased from 20% in 1989 to 16% in 1994 (r2 = 0.94, p = 0.005). The risk ratio for death remained unchanged over the study period and was 7-fold higher for patients with GNB than for patients without GNB. Factors independently associated with an increased hazard of death after GNB were: severity of illness as measured by exposure to intensive care (hazard ratio [HR], 1.5); age = 66-79 y (HR 1.8); GNB due to Klebsiella spp. (HR 1.7) or Pseudomonas aeruginosa (HR 1.6); and polymicrobial infection (HR 1.6). Multi-resistance was not associated with an increased risk of death (HR 1.0). Although the crude mortality of GNB decreased, the population-attributable risk ratio for death remained significant. These data suggest the absence of a major impact of multi-resistant GNB on patient mortality.

Between August 1994 and September 1996, 28 glycopeptide-resistant enterococci (GRE) were isolated from 8 infected patients and 11 intestinal carriers hospitalized at the University Hospital of Geneva. Identification to the species was made by both phenotypic (API 20 STREP and Rapid ID 32 STREP systems, and Vitek Gram Positive Identification Card) and genotypic methods using a multiplex PCR assay developed also for the determination of the genotype of glycopeptide resistance ( vanA , vanB , vanC1 , and vanC2-C3 genes). Fifteen isolates were identified as Enterococcus faecium , 8 as E. gallinarum , 4 as E. faecalis , and 1 as E. hirae . All of the phenotypic identification methods failed to differentiate some isolates of E. gallinarum from E. faecium , or vice versa. Both vanA ( n = 18) and vanB ( n = 4) glycopeptide resistance genotypes were found. For the first time, the vanB determinant was found in two isolates of E. gallinarum . Two patients were colonized by two different species containing the vanA gene and one by two different species containing the vanB gene. All vanA isolates were highly resistant to both vancomycin and teicoplanin except for three isolates which were susceptible to teicoplanin. Molecular typing by pulsed-field gel electrophoresis showed identical or similar patterns among E. faecium isolates with the vanA gene in five patients for whom the epidemiological link could not be always elucidated. This study emphasizes the necessity of utilizing both phenotypic and genotypic methods to characterize GRE.

Resume A l'heure actuelle, les infections a Chlamydia trachomatis sont les MST les plus frequentes enSuisse. Differents tests diagnostiques directs sont disponibles pour la recherche de ce pathogene dans les echantillons uro-genitaux mais la PCR (Polymerase Chain Reaction) est evaluee comme la technique la plus sensible. Dans cette etude nous avons compare la PCR commercialisee (Amplicor Chlamydia trachomatis, Roche Diagnostic Molecular Syst.) avec une autre technique d'amplification la LCR (Ligase Chain Reaction) developpee par Abbott (LCx Chlamydia trachomatis assay). Au total, 1 140 echantillons genitaux ou urinaires (956 de femmes et 184 d'hommes) ont ete analyses prospectivement. Parmi ceux-ci, 27 ont ete positifs dans le collectif feminin et 5 dans le collectif masculin. La prevalence a ete identique et faible dans les deux groupes (2,7%). La sensibilite entre les resultats PCR et LCR a ete similaire avec quelques resultats divergents qui ont pu etre expliques, dans la plupart des cas, par des problemes d'inhibition de l'amplification. Les inhibiteurs dans la technique LCR ont ete testes sur 205 prelevements. Une inhibition a ete detectee dans 6,3 % des prelevements et uniquement dans des frottis cervicaux. Le grand avantage du test LCx Abbott est la facilite de manipulation et le gain de temps pour executer une serie de tests (4 a 5 heures).

Gastrointestinal infections remain a frequent disease worldwide. In order to increase our knowledge of the epidemiology for our patient population, we retrospectively analyzed the results obtained for stool samples received at the clinical microbiology laboratory of the University Hospital of Geneva during a 4-year period. A total of 13,965 specimens from 7,124 patients (1.96 specimens per patient) were cultured, yielding 369 (2.6%) Salmonella spp., 408 (2.9%) Campylobacter spp., and 79 (0.6%) Shigella spp. The cumulative positivity rate of 6.1% decreased to 2.7% when patients received antimicrobial agents (P < 0.001). The positivity rate for 5,912 specimens obtained from patients hospitalized for < or = 3 days was 12.6%, whereas it dropped to 1.4% for patients hospitalized for > 3 days (P < 0.001). Of 3,837 stool samples originating from pediatric patients, 8.8% were positive, and 5.1% of 10,128 samples from adults were positive (P < 0.001). The cytotoxin of Clostridium difficile was detected in 379 of 3,723 samples analyzed (10.2%), and rotaviruses were detected in 190 of 1,601 samples (11.9%). We recommend that the use of cultures for enteric bacterial pathogens be restricted to patients hospitalized for < or = 3 days, with the exceptions of follow-up samples, specimens from immunocompromised patients, and patients whose first sample was culture negative or in the rare event of nosocomial food-borne outbreaks. For patients under antimicrobial therapy, testing for cytotoxin of C. difficile should primarily be requested; this analysis should also be accepted for samples from patients not receiving antimicrobial agents at the time of specimen collection. By applying these restrictions, we could have saved at least $5,000 annually.

The in vitro activity of cefpirome, a new parenteral fourth-generation cephalosporin, was investigated in the 5 university hospitals of Switzerland, and compared to 9 other antibiotics mainly used in hospitals, such as ceftazidime, ceftriaxone, cefotaxime, piperacillin, imipenem, gentamicin, vancomycin, ciprofloxacin and ofloxacin. A total number of 992 strains collected only from intensive care units and haematology-oncology units were tested by microdilution according to NCCLS. Cefpirome showed an excellent activity against all Enterobacteriaceae (MIC90 = 4 mg/l), methicillin-susceptible staphylococci (MIC90 = 1 mg/l), Streptococcus pneumoniae (MIC90 = 0.25 mg/l) and Haemophilus influenzae (MIC90 = 0.12 mg/l) isolates. Its activity was superior to that of third-generation cephalosporins against cephalosporinase-depressed mutants of Enterobacter cloacae and Citrobacter freundii isolates (MIC9032 mg/l for third-generation cephalosporins vs 4 mg/l for cefpirome). The MICs of cefpirome of 3 strains of Klebsiella spp. with an extended-spectrum-beta-lactamase were lower (MIC90 = 2 mg/l) than those of third-generation cephalosporins (MICs9032 mg/l). Against Pseudomonas aeruginosa cefpirome was as active as ceftazidime. The activity of cefpirome was poor against methicillin-resistant staphylococci, enterococci and nosocomial Gram-negative bacteria such as Stenotrophomonas maltophilia.

Two patients admitted to two different medical wards of our institution following respiratory decompensation of chronic obstructive pulmonary disease (COPD) were subsequently transferred to the same room of the medical intensive care unit (ICU) and intubated. Both patients developed invasive pulmonary aspergillosis and died soon after. Because COPD itself is rarely associated with lethal pulmonary aspergillosis, both cases were reviewed, and a retrospective investigation was conducted. Both patients had repeated sputum cultures while on the medical ward before their admission to the ICU; none of the sample grew Aspergillus spp. A. fumigatus was found in tracheal aspirates of both patients from the first day of their intubation while in the ICU. The pulmonary condition of both patients worsened, and invasive aspergillosis was diagnosed by bronchoalveolar lavage. Despite therapy with amphotericin B, the patients died 16 and 22 d after intubation, respectively. Both deaths were attributed to pulmonary aspergillosis; autopsy confirmed a massive pneumonia of the five lobes due to A. fumigatus in one patient. Investigation revealed that an air filter had been replaced 30 h before the first patient was admitted to the room. Experimental air filter replacement performed 12 d after the second patient died revealed the presence of A. fumigatus on the surface of the filters as well as a 10-fold increase in room air fungal counts during the procedure. This study shows that exposure to high concentrations of airborne Aspergillus spp. related to air filter change was associated with fatal invasive aspergillosis in two mechanically ventilated patients. Such infection can be prevented by the establishment and application of guidelines for air filter replacement.

The prognosis in patients with sepsis depends on severity of acute illness, underlying chronic diseases, and complications associated with infection. Adjusting for these factors is essential for evaluation of new therapies. The purpose of the present study was to determine variables readily identifiable at the bedside that predict mortality in intensive care unit (ICU) patients with sepsis and positive blood cultures. For a 5-yr period, all patients of a surgical ICU presenting with positive blood cultures and sepsis were systematically analyzed for clinical variables and organ dysfunctions at the day of onset of sepsis and bacteremia and during the subsequent clinical course. The prognostic value of these variables was determined using logistic regression procedures. Of the 5,457 admissions to the ICU, 176 patients developed sepsis with positive blood cultures (3.2 per 100 admissions). The fatality rate was 35% at 28 days after the onset of sepsis; in-hospital mortality was 43%. Independent predictors of mortality at onset of sepsis were previous antibiotic therapy (odds ratio [OR], 2.40; 95% confidence interval [CI95], 1.59 to 3.62; p = 0.034), hypothermia (OR, 1.43; CI95, 1.04 to 2.44; p = 0.030), requirement for mechanical ventilation (OR, 2.97; CI95, 1.96 to 4.51; p = 0.009), and onset-of-sepsis APACHE II score (OR, 1.21; CI95, 1.13 to 1.29; p < 0.001). Vital organ dysfunctions developing after the onset of sepsis influenced outcome markedly. The best two independent prognostic factors were the APACHE II score at the onset of sepsis (OR, 1.13 per unit; CI95, 1.08 to 1.17; p = 0.0016) and the number of organ dysfunctions developing thereafter (OR, 2.39; CI95, 2.02 to 2.82; p < 0.001). In ICU patients with sepsis and positive blood cultures, outcome can be predicted by the severity of illness at onset of sepsis and the number of vital organ dysfunctions developing subsequently. These variables are easily assessed at the bedside and should be included in the evaluation of new therapeutic strategies.

A woman born in 1920 has suffered from a chronic destructive lung disease since 1972, with development of a severe combined restrictive and obstructive ventilatory defect. Large quantities of acid-fast microorganisms have been repeatedly observed in her sputum. Multiple courses of antimycobacterial treatment did not stop the progression of the disease. The mycobacterium involved was first identified as Mycobacterium gordonae, and later as Mycobacterium scrofulaceum. Analysis of part of the amplified gene of the 16S rRNA, however, revealed that its sequence differed from that of any established mycobacterial species, although it was observed once before in a German lymph node isolate, for which the name "Mycobacterium interjectum" has been proposed. Retrospective analysis confirmed the presence of this sequence in frozen samples which had been provided by the patient in 1983, 1985, 1989, 1990, and 1993. Our case confirms the value of amplification and sequencing of mycobacterial 16S rRNA for classifying mycobacteria, and suggests that "Mycobacterium interjectum" may be involved in cases of chronic destructive lung disease.

To determine their ability to detect blood-borne pathogens, the blood culture media BCB Release (Becton Dickinson, USA) and Signal (Oxoid, UK) were evaluated on a total of 5,122 blood culture sets. Each of the two bottles was inoculated with an equal amount of blood from 2,262 patients at bedside (2.3 cultures per patient). In the laboratory, agar-coated paddles were attached to the BCB Release bottles and the Signal device was mounted onto the Signal bottles. Both systems were incubated at 35 degrees C for seven days. A total of 608 (11.9%) sets were positive, from which 549 pathogenic microorganisms could be isolated. These could be grown significantly (p0.0001) more often from the BCB Release broth (n = 483) than from the Signal system (n = 384). Mainly staphylococci, Escherichia coli and yeasts were isolated more often from the BCB Release, anaerobes were more often detected from the Oxoid Signal. The time to positivity was significantly shorter (p0.0001) with the BCB Release. The Signal system proved a valuable complement to the BCB Release broth.

Antibacterial drugs are overused and often inappropriately selected. This exacerbates drug resistance and exacts a high burden from acute respiratory tract, bloodstream, sexually-transmitted, diarrheal and other infections. Appropriate use of existing diagnostic tests, and developing better ones, could avert these costs and would avoid selective pressure from unnecessary antibacterial use. Product profiles of resistance-averting tests would specify WHO ASSURED (Affordable, Sensitive, Specific, User-friendly, Rapid and Robust, Equipment-free and Deliverable) criteria and request susceptibility as well as etiological information. Advances in genomics, nanoscience, microfluidics and bioengineering, as well as innovative funding paradigms can help to overcome research and development barriers for such diagnostics if they are deliberately and forcefully applied. Rapid uptake of new tests requires timely translation of research on cost-benefit analyses into policy, value-based subsidies and reimbursements, as well as behavioral change of health care providers and users.

During recent years, a resurgence of interest in the macrolides had led to the discovery of new derivatives of erythromycin with improved antibacterial activity and pharmacokinetic properties. In this study the in-vitro and in-vivo antistaphylococcal activity of S-5556, a 16-membered macrolide, was evaluated. In vitro, S-5556 was slightly less active than erythromycin against methicillin-susceptible Staphylococcus aureus. In contrast, it had superior activity for methicillin-resistant S. aureus (MRSA); several of these strains with inducible resistance to the macrolides-lincosamides-streptogramins group were susceptible to S-5556 whereas erythromycin was inactive. The combination of S-5556 with oxacillin was synergic for most MRSA strains tested. In vivo, a single prophylactic dose of S-5556 prevented 75%-100% of the cases of acute staphylococcal subcutaneous foreign body infection in a guinea pig-model. In a rat-model of chronic implant infection due to a methicillin- and erythromycin-resistant S. aureus strain, S-5556 significantly decreased the bacterial concentration around the foreign material, however resistant mutants emerged.

Substantial efforts have been devoted to improving the means for early and accurate diagnosis of ventilator-associated (VA) pneumonia in intensive care unit (ICU) patients because of its high incidence and mortality. A good diagnostic yield has been reported from quantitative cultures of bronchoalveolar lavage (BAL) fluid or a protected specimen brush, both obtained by fiberoptic bronchoscopy. As bronchoscopy requires specific skills and is costly, we evaluated a simpler method to obtain BAL fluid, that is, by a catheter introduced blindly into the bronchial tree. Quantitative cultures from bronchoscopically sampled BAL (B-BAL) and blindly nonbronchoscopically collected BAL (NB-BAL) were assessed for sensitivity, specificity, and predictive value for the diagnosis of VA pneumonia. A total of 40 pairs of samples were examined in 28 patients requiring prolonged mechanical ventilation and presenting a high risk of developing pneumonia. For comparison with bacteriologic data we defined a clinical score for pneumonia ranging from zero to 12 using the following variables: body temperature, leukocyte count, volume and character of tracheal secretions, arterial oxygenation, chest X-ray, Gram stain, and culture of tracheal aspirate. To quantify the bacteria in BAL the bacterial index (BI) was used, defined as the sum of the logarithm of the number of bacteria cultured per milliliter of BAL fluid. A good correlation between clinical score and quantitative bacteriology was observed (r = 0.84 for B-BAL and 0.76 for NB-BAL; p less than 0.0001). Similar to studies in baboons, patients with pulmonary infection could be distinguished by a BI greater than or equal to 5 with a sensitivity of 93% and a specificity of 100% (B-BAL).(ABSTRACT TRUNCATED AT 250 WORDS)

Group A beta-hemolytic streptococcus (GAS) meningitis is a rare disease in adults. We conducted a retrospective study to describe clinical and microbiological features of nine cases of GAS meningitis in Switzerland. Of nine patients, six had neurosurgical conditions, and five had upper respiratory tract infections. Eight cases were community-acquired. The outcome of GAS meningitis was favorable; only one patient died of neurosurgical complications. No patient presented with toxic shock syndrome. Serotyping failed to reveal a dominant strain, and genotyping revealed that two strains carried the gene encoding the streptococcal pyrogenic exotoxin C and that one strain carried the gene encoding the streptococcal pyrogenic exotoxin A. Our observations suggest that GAS meningitis in adults is associated with neurosurgical conditions and/or an upper respiratory tract infection.

This international collaborative study evaluates a new system (ATB 32 Staph) for the identification of staphylococci taking into account the new novobiocin-sensitive and -resistant species reported. This study involved eight laboratories and 792 strains were tested. The reproducibility obtained for the cumulative results of the inter- and intea-laboratory tests was more than 90%. For 713 strains relevant of a species 95.5% were correctly identified by the system. Eight strains (1.2%) were misidentified and 24 strains (3.3%) were not identified. For 79 strains initially considered as not-classified, 62% were identified at the species level by the new system. The newer ATB 32 Staph gallery is a performant and useful method for routine identification of the currently described staphylococci species from clinical and animal origin.

UTI remain among the most frequent infections in community and in hospitals. The treatment depends on age, sex, likely site of infection, predisposing factors, recurrence and pregnancy. Nitrite and leucocyte esterase tests are sufficient for the diagnosis and a 3 day treatment of uncomplicated UTI. Urine cultures are necessary for the correct management of complicated UTI which need a 10–14 days course of antibiotics. In this case an initial iv treatment can be switched to peroral treatment as soon as the patient is stable. Catheter-related infections are treated only if symptomatic and for a short period of time to avoid the development of resistance.

A commercial system for the rapid detection of methicillin-resistant Staphylococcus aureus, the BBL Crystal MRSA test (C-MRSA ID; Becton Dickinson, USA), was evaluated prospectively and compared with a polymerase chain reaction test for the presence of the mecA gene. Ten European centres tested a total of 676 isolates of Staphylococcus aureus from blood cultures. The system correctly identified 661 (97.8%) isolates within 4 h. All but three mecA gene-negative isolates (99.4% specificity) yielded a negative C-MRSA ID reaction, and 158 of 170 mecA gene-positive isolates were accurately detected (92.9% sensitivity). After repeated testing of discrepant results, sensitivity and specificity increased to 99% and 100%, respectively.

OBJECTIVE: To assess the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in Switzerland. MATERIAL AND METHODS: One-year national survey of all MRSA cases detected in a large sample of Swiss healthcare institutions (HCI). Analysis of epidemiological and molecular typing data (PFGE) of MRSA strains. RESULTS: During 1997, 385 cases of MRSA were recorded in the 5 university hospitals, in 33 acute care community hospitals, and 14 rehabilitation or long-term care institutions. Half of the cases were found at the University of Geneva Hospitals where MRSA was already known to be endemic (41.1 cases/10,000 admissions). The remaining cases (200) were distributed throughout Switzerland. The highest rates (>100 cases/10,000 admissions) were reported from non-acute care institutions. Rates ranged from 3.3 to 41.1 cases/10,000 admissions for university hospitals (mean 15.5); 0.67 to 90.4 for community hospitals (mean 4.8), and 28.2 to 315 for non-acute care institutions reporting MRSA (mean 85.7). Forty percent of MRSA patients were infected, while 60% were only colonised. The leading infection sites were skin and soft tissue (21%), surgical site (15%), and the urinary tract (26%). Whereas in Eastern Swiss HCI most MRSA cases occurred in acute care hospitals (n = 47, 98%), rehabilitation and long-term care institutions accounted for an important number of the identified cases (n = 107, 38%) in Western Switzerland. CONCLUSION: Low rates of MRSA were still observed in Swiss HCI, despite one outlying acute care centre with endemic MRSA and some nonacute care institutions with epidemic MRSA. Rehabilitation and long-term care institutions contributed to a substantial proportion of cases in Western Switzerland and may constitute a significant reservoir. Overall, a national approach to surveillance and control of MRSA is mandatory in order to preserve a still favourable situation, and to decrease the risk of epidemic MRSA dissemination.

We report on a case of a postneurosurgical meningitis due to ceftriaxone-susceptible Proteus penneri , with selection of a ceftriaxone-resistant isolate following treatment with ceftriaxone. The isolates presented identical patterns by pulsed-field gel electrophoresis and produced a single β-lactamase named HugA with an isoelectric point of 6.7. The ceftriaxone-resistant isolate hyperproduced the β-lactamase (increase in the level of production, about 90-fold). The sequences of the hugA β-lactamase gene and its regulator, hugR , were identical in both P. penneri strains and had 85.96% homology with those of Proteus vulgaris . The HugA β-lactamase belongs to molecular class A, and the transcriptional regulator HugR belongs to the LysR family.

Many patients who present with Pseudomonas aeruginosa bacteremia have been previously exposed to antibiotics. To assess whether resistance of bacteremic strains to antipseudomonal antibiotics (piperacillin, ceftazidime, imipenem, ciprofloxacin, or aminoglycosides) is associated with previous exposure to these drugs, a case-control study including 267 cases of P. aeruginosa bacteremia was conducted. Twenty-five percent of the episodes had been preceded by the exposure to an antipseudomonal antibiotic. Eighty-one strains were resistant to at least 1 antibiotic; 186 were susceptible to all drugs. Via univariate analysis, the risks of resistance to ceftazidime and imipenem were found to be significantly associated with previous receipt of these agents. Using multivariate analysis, exposure to any antipseudomonal antibiotic as a monotherapy was found to be associated with an increased risk of subsequent resistance to itself (odds ratio, 2.5; P = .006). Therefore, clinicians should avoid readministering previously prescribed antibiotics when initiating empiric therapies for possible P. aeruginosa bacteremia, especially when they have been given as monotherapies

Le but de cette etude a ete de determiner la prevalence de la colonisation des voies aeriennes par les mycoplasmes genitaux chez les enfants prematures et d'evaluer la possible association de cette colonisation avec le developpement d'une maladie pulmonaire chronique. Patients et methodes. - La prevalence de la colonisation par les mycoplasmes genitaux a ete determinee de maniere prospective par des cultures des secretions nasopharyngees ou endotracheales de nouveau-nes prematures de moins de 32 semaines de gestation. La relation entre une colonisation par Ureaplasma urealyticum et le developpement d'une maladie pulmonaire chronique a ete analysee. Resultats. - Cinquante-neuf nouveau-nes ont ete inclus dans l'etude et 11 (19 %) etaient colonises par U. urealyticum. Dans le sous-groupe des 45 nouveau-nes ventiles, les sept nouveau-nes colonises par U. urealyticum ont developpe une maladie pulmonaire chronique versus dix sur 38 (26 %) pour les enfants non colonises (risque relatif: 3,8; intervalle de confiance a 95 %: 2,2-6,5, p < 0,001). Dans ce sous-groupe, les nouveau-nes colonises avaient un poids median de naissance inferieur (760 g versus 1 083 g, p = 0,04), un âge gestationnel inferieur (26 versus 28 semaines, p = 0,03) et avaient plus souvent un canal arteriel persistant (p = 0,03). Ces differents facteurs confondants pourraient expliquer la relation entre la colonisation par U. urealyticum et une maladie pulmonaire chronique. Pourtant, cette association est restee significative quand l'analyse etait restreinte aux enfants de moins de 1 000 g (risque relatif: 2,3; intervalle de confiance a 95 %: 1,3-4, p = 0,02) ou aux enfants ayant un canal arteriel persistant (risque relatif: 2; intervalle de confiance a 95 %: 1,3-3,1, p = 0,02). Conclusion. - La colonisation par U. urealyticum est un facteur de risque significatif pour le developpement d'une maladie pulmonaire chronique.

The aim of the present study was to assess the hypothesis that, when present in nasopharyngeal secretions, Streptococcus pneumoniae. Haemophilus influenzae, and Moraxella catarrhalis play a pathogenic role early in the course of an upper respiratory tract infection. Adults with a clinical diagnosis of acute sinusitis or common cold were enrolled. Participants were randomly assigned in a double-blind manner to receive azithromycin 500 mg daily or placebo for 3 days. The effect of treatment on symptom evolution in the predefined subset of patients with Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis in their nasopharyngeal secretions was assessed. Of 265 patients enrolled, 132 received placebo and 133 azithromycin. Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis was identified in nasopharyngeal secretions of 77 patients (29%). In this predefined subgroup of patients with Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis, resolution of symptoms by day 7 occurred in 73% of those treated with azithromycin compared with 47% of those who received placebo (P=0.007). The median time before resolution of symptoms was 5 days in the azithromycin group compared to 7 days in the placebo group. Respiratory complications requiring antibiotic treatment occurred in 19% of patients in the placebo group and in 3% of the azithromycin group (P=0.025). In the remaining 188 patients without Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis, resolution of symptoms by day 7 was similar in both groups (69% in the placebo group vs. 64% in the azithromycin group [P=0.75]). Antibiotic treatment is of clinical benefit for patients with acute sinusitis or common cold when Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis is present in nasopharyngeal secretions. This observation provides new insights into the pathogenic role of these bacteria in the early stage of the common cold.

The Wellcolex Colour Salmonella Test was evaluated for detection of Salmonella spp. in enrichment broths of 1,010 stool samples. In 39 specimens, Salmonella spp. could be isolated from the selenite F broth (SF). Wellcolex agglutination indicative of the presence of Salmonella spp. was noted with the SF in 36 cases, 34 of which were in agreement with the subculture results. Therefore, relative to subculture, the sensitivity and specificity of the Wellcolex-selenite F procedure were 87 and 99%, respectively. Five false-negative results were noted. The gram-negative broth (GN) subculture revealed only 23 Salmonella spp. (59% sensitivity). The Wellcolex agglutination procedure applied to the GN indicated Salmonella spp. for 21 samples; its sensitivity was 70% and its specificity was 99% compared with GN subcultures. The Wellcolex agglutination procedure applied to the SF performed better than the agglutination of GN or direct plating procedures and detected 17 of the 39 Salmonella spp. at least 24 h earlier than did culture.

BACKGROUND: Diagnosis of ventilator associated pneumonia can be made by quantitative cultures of bronchoalveolar lavage fluid or of protected specimen brushings, though cultures require 24-48 hours to provide results. In 80% of cases aerobic Gram negative bacteria are the cause. METHODS: A rapid diagnostic method of assessing the endotoxin content of lavage fluid by Limulus assay is described. Forty samples of lavage fluid were obtained from patients with multiple trauma requiring mechanical ventilation for a prolonged period. Pneumonia was diagnosed on the basis of clinical, radiological, and bacteriological findings, including quantitative cultures of lavage fluid. RESULTS: A relation was observed between the concentration of endotoxin in lavage fluid and the quantity of Gram negative bacteria. The median endotoxin content of lavage fluid in Gram negative bacterial pneumonia was 15 endotoxin units (EU)/ml; the range observed in individual patients was 6 to > 150 EU/ml. In patients with pneumonia due to Gram positive cocci and in non-infected patients the median endotoxin level was 0.17 (range < or = 0.06 to 2) EU/ml. An endotoxin level greater than or equal to 6 EU/ml distinguished patients with Gram negative bacterial pneumonia from colonised patients and from those with pneumonia due to Gram positive cocci. CONCLUSION: The measurement of endotoxin in lavage fluid is a rapid (less than two hours) and accurate diagnostic method. It should allow specific and early treatment of Gram negative bacterial pneumonia.

The Bactec MGIT 960 system (Becton Dickinson, USA), designed for the culture of mycobacteria, was compared with the Bactec 460 instrument and culture on two solid egg-based media using a total of 1024 clinical specimens. Mycobacteria could be identified from 99 (9.7%) specimens, 89 (90%) of which were identified by the Bactec 960 system, 90 (91%) by the Bactec 460 system, and 82 (83%) by culture on the two egg-based media. The Bactec 960 cultures became positive an average of 16.7 days after specimen collection, the Bactec 460 cultures 14.9 days after collection, and the cultures on egg-based media 26.2 days after collection. The Bactec 960 is a compact and highly automated nonradiometric system that may replace the Bactec 460 system.

Background: The aetiology of sarcoidosis remains controversial. An infectious origin is often discussed, but only anti-inflammatory or immunosuppressive treatment is recommended. Objectives: To investigate the hypothesis of bacterial origin by treating cutaneous sarcoidosis with antibiotics. Methods: Patients with chronic cutaneous sarcoidosis, unresponsive to the usual treatment and not requiring systemic corticotherapy, were given combined antibiotherapy for 6 months. Search for bacterial DNA by amplification and sequencing of the 16S ribosomal RNA gene in skin biopsies of lesions before and after antibiotherapy was done. Results: Three patients received a combined treatment with clarithromycin 1 g/day and ciprofloxacin 1 g/day. No clinical changes occurred in 2 cases and transient worsening in 1. Amplification for bacterial DNA was positive in all skin biopsies. The sequencing of this DNA could not identify a unique bacterial species. Conclusion: No evident bacterial origin could be demonstrated; however, this approach should be extended to more patients.

We determined risk factors associated with persistent carriage of methicillin-resistant Staphylococcus aureus (MRSA) among 102 patients enrolled in a double-blind, placebo-controlled trial of nasally administered mupirocin ointment. MRSA decolonization was unsuccessful in 77 (79%) of 98 patients who met the criteria for evaluation. By univariate analysis, 4 variables were found to be associated with persistent MRSA colonization (P or = 2 MRSA-positive body sites, and low-level mupirocin resistance. After multivariable Cox proportional hazards modeling, the presence of > or = 2 positive body sites (adjusted hazard ratio [AHR], 1.7; 95% confidence interval [CI], 1.0-2.9) and previous receipt of a fluoroquinolone (AHR, 1.8; 95% CI, 1.0-3.3) were independently associated with MRSA persistence, whereas nasal mupirocin tended to confer protection (AHR, 0.6; 95% CI, 0.4-1.0). Low-level mupirocin resistance was observed in 9 genotypically different MRSA strains and was not independently associated with chronic MRSA carriage (AHR, 1.5; 95% CI, 0.9-2.5). Our findings suggest that multisite MRSA carriage and previous receipt of a fluoroquinolone are independent risk factors for persistent MRSA colonization.

In a study to determine the prevalence and antimicrobial susceptibility of bacterial pathogens in the oropharynx of healthy children, throat swabs obtained from 1765 children were cultured and the organisms recovered tested by the disk diffusion method and the E test. Six hundred ninety-one children (39.1%) harbored Haemophilus influenzae, 112 (6.3%) Streptococcus pyogenes, 73 (4.1%) Moraxella catarrhalis, 52 (2.9%) Streptococcus pneumoniae, and 50 (2.8%) Neisseria meningitidis in their oropharynx. The rate of penicillin resistance was 2%, 0%, and 12%, respectively, for Streptococcus pneumoniae, Streptococcus pyogenes, and Neisseria meningitidis. Ampicillin resistance was observed in 8.6% of Haemophilus influenzae strains and 78% of Moraxella catarrhalis strains and was associated with the presence of beta-lactamase, except in one strain of Haemophilus influenzae. Five (4.4%) isolates of Streptococcus pyogenes were resistant to macrolides. The low level of resistance observed in this area contrasts with the high rates reported in the literature.

The use of the COBAS AMPLICOR System (Roche Molecular Diagnostics, Basel, Switzerland), the only automated system for PCR testing, was evaluated for a rapid identification of mycobacteria with positive BACTEC 12B cultures. Two hundred ninety-six specimens with a growth index of ≥30 were analyzed for the presence of Mycobacterium tuberculosis complex, Mycobacterium avium , and Mycobacterium intracellulare . Compared to traditional methods and provided that samples with PCR inhibition are retested at a 1:10 dilution, the sensitivity and specificity of the COBAS AMPLICOR System with BACTEC 12B cultures were 100 and 98%, respectively. The COBAS AMPLICOR method is rapid and reliable for identifying the most common mycobacteria in cultures.

ObjectiveTo characterize antimicrobial resistance patterns to amikacin (AN) and gentamicin (GM) among Gramnegative bloodstream isolates and to determine the possible relationship between use of AN and GM and the occurrence of antibiotic resistance during a 6-year period.MethodsStandard media and techniques of isolation and identification were used. Antimicrobial susceptibility testing was performed with the disk diffusion method and API rapid ATE E strips. Data on consumption of aminoglycosides were collected by the central hospital pharmacy and were expressed as daily defined doses.ResultsOne thousand nine hundred and four bloodstream isolates were tested for AN and GM susceptibility between 1989 and 1994. Activities of AN and GM remained high during the study period against most isolates of Gram-negative bacteria. No relationship could be observed between the use of AN/GM and the rate of AN/GM resistance. Nosocomial Gram-negative No relationship could be bloodstream isolates showed a higher degree of resistance towards both AN (3.9% of all nosocomial iveisolates) and GM (7.9%) than community-acquired isolates (1.8% toward AN and 3.1% towards GM, respectively). There was a significant increase (7.9%)than(P= 0.004) in the risk of GM resistance in patients with nosocomial Gram-negative bacteremia detected more than 14 days after admission. The proportion of GM-susceptible Pseudornonas aeruginosa isolates detected decreased linearly from 97% for infections acquired between day 3 and day 10 following admission to 80% for bacteremia developing 30 days or more after admission (P= 0.008).ConclusionsAN and GM remain highly active antimicrobial drugs for treatment of GNB in times of growing resistance to cephalosporins and fluoroquinolones.

The MB/BacT automated system is designed for the isolation of mycobacteria from clinical specimens. It utilizes a colorimetric sensor and reflected light to continuously monitor the CO2 concentration in the culture medium. We compared its performance to that of the BACTEC 12B media for the radiometric BACTEC 460 instrument and that of solid culture media. Respiratory specimens and urine samples were decontaminated with 4% NaOH. The vials of the two instruments were inoculated with 500 microl of sample and two solid egg-based media at 200 microl each. All vials were incubated at 37 degrees C for 6 weeks. A total of 1,078 specimens (633 respiratory specimens, 78 cerebrospinal fluid specimens, 177 other body fluid specimens, 87 urine specimens, and 103 other types of specimens) were cultured in parallel. Mycobacteria could be identified from 73 (6.8%) specimens: 67 M. tuberculosis, 3 M. kansasii, 1 M. xenopi, 1 M. terrae, and 1 mixed M. avium with M. scrofulaceum. Of these, 63 (86.3%) specimens were positive with the MB/BacT system, 67 (91.8%) were positive with the BACTEC 460 instrument, and 58 (79.5%) were positive with the two egg-based media. MB/BacT cultures were positive on average after 17.5 (+/-6.4) days, BACTEC cultures with a growth index of >20 (mean, 200) were positive after 14.3 (+/-8.2) days, and egg-based media were positive after 24.2 (+/-7.5) days. Microorganisms other than mycobacteria contaminated 46 (4.3%) MB/BacT cultures and 31 (2.9%) BACTEC cultures, which had to be discarded. The MB/BacT system is a well-automated system for the detection of M. tuberculosis in clinical specimens without using radioactive reagents. Further trials are required to determine whether it is suitable for the culture of nontuberculous mycobacteria.

The BACTEC 9240 (Becton Dickinson, Sparks, Md.) automated blood culture system is based on the continuous monitoring of CO2 production by means of a fluorescent sensor attached to the bottom of a culture vial. We compared two media for this system, resin-containing Plus aerobic/F and Lytic anaerobic/F. Sets of Plus aerobic/F and Lytic anaerobic/F vials inoculated with similar volumes (9 +/- 2.5 ml) were evaluated. In the laboratory, the vials were introduced into the system in accordance with the recommendations of the manufacturer and incubated at 35 degrees C for 5 days. A total of 10,914 sets consisting of two bottles each were obtained from 3,674 patients (2.97 cultures per patient). Of these, 1,233 (11%) were culture positive, including 1,074 (10%) yielding at least one pathogen, and 178 (2%) were contaminated. A total of 1,135 isolates were considered clinically relevant in 624 septic episodes; we isolated 894 from Plus aerobic/F and 852 from Lytic anaerobic/F (P = 0.06 [not significant]). More S. aureus isolates (P = 0.05), Pseudomonas spp. (P < 0.0001), other gram-negative bacteria (P = 0.004), and yeasts (P < 0.0001) were isolated from Plus aerobic/F medium, but more streptococci (P < 0.0001), E. coli (P = 0.02) strains and anaerobes (P < 0.0001) were detected with Lytic anaerobic/F medium. Lytic anaerobic/F vials were significantly (P < 0.0001) more often positive at least 6 h before Plus aerobic/F vials (n = 112 versus 52, respectively). Significantly more (P < 0.0001) Plus aerobic/F vials (n = 210; 1.9%) than Lytic anaerobic/F vials (n = 42; 0.4%) were unconfirmed positives. Plus aerobic/F and Lytic anaerobic/F proved to be a valuable pair of blood culture media. Plus aerobic/F performs better for patients under antibiotic treatment, due to the antimicrobial-neutralizing effect of resins. For patients without antibiotic therapy, more microorganisms could be isolated from Lytic anaerobic/F due to cell lysis.