Development of a 5′-Nuclease Real-Time PCR Assay Targeting fliP for the Rapid Identification of Burkholderia mallei in Clinical Samples

Background: Burkholderia mallei is a potential biological agent that causes glanders or farcy in solipeds, a disease notifiable to the Office International des Epizooties (OIE). The number of reported outbreaks has increased steadily during the last decade, but diagnosis is hampered by the low bacterial load in infected tissues and excretions.

Methods: We developed a B. mallei-specific 5′-nuclease real-time PCR assay that targets the fliP gene of B. mallei and includes an internal amplification control. Specificity was assessed with 19 B. mallei strains, 27 Burkholderia pseudomallei strains, other Burkholderia strains of 29 species, and clinically relevant non-Burkholderia organisms.

Results: Amplification products were observed in all B. mallei strains but in no other bacteria. The linear range of the B. mallei real-time PCR covered concentrations from 240 pg to 70 fg of bacterial DNA/reaction. The detection limit was 60 fg of B. mallei DNA. The clinical applicability of the assay was demonstrated by use of organ samples from diseased horses of a recent outbreak that was reported to the OIE by the United Arab Emirates in 2004.

Conclusions: Compared with conventional PCR, our rapid 5′-nuclease real-time PCR assay for the specific identification of B. mallei has a lower risk of carryover contamination and eliminates the need for post-PCR manipulations. This real-time PCR assay also shortens the turnaround time for results and has the potential for automation.

Antimicrobial susceptibilities of Austrian Francisella tularensis holarctica biovar II strains

The antibiotic susceptibilities of 50 Francisella tularensis subsp. holarctica biovar II strains isolated from hares and human patients from the eastern part of Austria were examined. Minimum inhibitory concentrations (MICs) of 24 antimicrobial agents were determined using Eteststrade mark on cysteine heart agar plates supplemented with 10% sheep blood. All isolates were sensitive to tetracyclines, aminoglycosides, quinolones, chloramphenicol and rifampicin. Resistance was observed in all isolates against macrolides, penicillins and aztreonam. Bacteria were resistant to cephalosporins and carbapenems, except for 8% of strains investigated that were susceptible or intermediately susceptible. Our in vitro susceptibility data can be applied for the detection and comparison of resistance development and to provide in vitro data for the guidance of therapy.

Seroprevalence of Anti-Yersinia Antibodies in Healthy Austrians

Yersiniosis is caused by Y. enterocolitica and Y. pseudotuberculosis mostly presenting as intestinal infection. The infection is usually acquired from contaminated food. The aim of this study was to determine the seroprevalence of anti-Yersinia antibodies in Austrians. Sera of 750 healthy Austrians from all nine states were tested for anti-Yersinia IgG antibodies using the recomBlot Yersinia Westernblot kit. Overall seroprevalence was 29.7%. Seroprevalence increased significantly with age from 24.7% in the group of the 19 to 24 year olds to 38.5% in the group of persons older than 44 years. The seroprevalence of anti-Yersinia antibodies varied within the states between 18% and 43.5%. The high seroprevalence of anti-Yersinia antibodies in contrast to only approximately 100 reported yersiniosis cases per year points to the fact that the majority of infections is either subclinical or mild.

Development of 5' nuclease real-time PCR assays for the rapid identification of the burkholderia mallei//burkholderia pseudomallei complex

Burkholderia pseudomallei is the causative agent of melioidosis and was classified as a biologic agent by the Centers for Disease Control and Prevention (Atlanta, GA). Acute melioidosis has a case fatality rate of >40%, and septicemia is fatal in up to 90%. The aim of the study was to design 5'-nuclease real-time PCR assays for the rapid and reliable identification of the B. mallei/B. pseudomallei complex. Real-time PCR assays using TaqMan probes targeting the 16S rDNA and fliC were developed on an ABI Prism 7000 sequence detection system (Applied Biosystems, Foster City, CA). Specificity was assessed with 64 B. pseudomallei, nine B. mallei, 126 other Burkholderia strains of 29 species, and 45 clinically relevant non-Burkholderia organisms. Sensitivity, specificity, and positive and negative predictive value of the assays were 100%. Discrimination between B. pseudomallei and B. mallei, an organism which can be regarded as a clone of B. pseudomallei, could not be achieved. A probit analysis revealed that 7.5 and 52 genome equivalents (GE) of B. pseudomallei could be detected using the fliC and the 16S rDNA assays (P = .05), respectively. In spiked blood samples, the detection limit was approximately 300 and 3.000 GE for fliC and the 16S rDNA, respectively. In conclusion, we recommend the simultaneous use of the 16S rDNA and fliC real-time PCR assays for the rapid and specific identification of the B. mallei/B. pseudomallei complex in positive blood cultures or from suspicious bacterial colonies allowing the early onset of appropriate antibiotic therapy.

[Percutaneous dilatative tracheostomy as a new method in intensive medicine. Procedure, advantages and risks]

BACKGROUND AND OBJECTIVE

Percutaneous dilatational tracheostomy (PDT) is a recently developed method to obtain endotracheal access, also at the bed-side, in ventilated patients. The procedure is described and results are presented.

PATIENTS AND METHODS

PDT was performed in 112 patients (82 men, 30 women, average age 50.7 years) between 1.5. 1994 and 31.5. 1996, in all cases expected to require more than 10 days of assisted ventilation. All complications, late sequelae and cosmetic results after decannulation were analysed.

RESULTS

No serious complications were noted during the procedure. Erroneous puncture occurred in nine patients, but were corrected without problem. Complications necessitating temporary interruption of the tracheostomy consisted of accidental extubation and ventilatory problems (two patients each). There were no late sequelae and the cosmetic results were judged to be very good.

CONCLUSION

PDT is a simple and relatively easily learned procedure. It has a low complication rate, late sequelae are very rare and cosmetic results after closure of the tracheostomy are excellent.