ABSTRACT
The Phoenix automated microbiology system (BD Diagnostics, Sparks, MD) is designed for the rapid identification (ID) and antimicrobial susceptibility testing (AST) of clinically significant human bacterial pathogens. We evaluated the performance of the Phoenix instrument in comparison with that of the MicroScan WalkAway system (Dade Behring, West Sacramento, CA) in the ID and AST of gram-negative clinical strains and challenge isolates of Enterobacteriaceae (n = 150) and nonfermentative gram-negative bacilli (NFGNB; 45 clinical isolates and 8 challenge isolates). ID discrepancies were resolved with the API 20E and API 20NE conventional biochemical ID systems (bioMerieux, Durham, NC). The standard disk diffusion method was used to resolve discordant AST results. The overall percentages of agreement between the Phoenix ID results and the MicroScan results at the genus and species levels for clinical isolates of Enterobacteriaceae were 98.7 and 97.7%, respectively; following resolution with conventional biochemical testing, the accuracy of the Phoenix system was determined to be 100%. For NFGNB, the levels of agreement were 100 and 97.7%, respectively. Both systems incorrectly identified the majority of the uncommon nonfermentative nonpseudomonal challenge isolates recovered from cystic fibrosis patients; these isolates are not included in the databases of the respective systems. For AST of Enterobacteriaceae, the rate of complete agreement between the Phoenix results and the MicroScan results was 97%; the rates of very major, major, and minor errors were 0.3, 0.2, and 2.7%, respectively. For NFGNB, the rate of complete agreement between the Phoenix results and the MicroScan results was 89.1%; the rates of very major, major, and minor errors were 0, 0.5, and 7.7%, respectively. Following the confirmatory testing of nine clinical isolates initially screened by the MicroScan system as possible extended-spectrum-beta-lactamase (ESBL)-producing organisms (seven Klebsiella pneumoniae isolates and two Escherichia coli isolates), complete agreement was achieved for eight isolates (one ESBL positive and seven negative); one false positive was obtained with the Phoenix instrument. The MicroScan system correctly detected the 10 ESBL challenge isolates, versus the 6 detected by the Phoenix system. Overall, there was good correlation between the Phoenix instrument and the MicroScan system for the ID and AST of Enterobacteriaceae and common NFGNB. The Phoenix system is a reliable method for the ID and AST of the majority of clinical strains encountered in the clinical microbiology laboratory. Until additional performance data are available, results for all Klebsiella pneumoniae or Klebsiella oxytoca and E. coli isolates screened and confirmed as ESBL producers by any automated system should be confirmed by alternate methods prior to the release of final results.
Subject(s)
Bacteriological Techniques/methods , Drug Resistance, Bacterial , Gram-Negative Bacteria/drug effects , Gram-Negative Bacteria/isolation & purification , Gram-Negative Bacterial Infections/diagnosis , Automation , Bacterial Typing Techniques/methods , Cystic Fibrosis/complications , Gram-Negative Bacteria/growth & development , Gram-Negative Bacterial Infections/microbiology , Humans , Microbial Sensitivity Tests/methods , Sensitivity and SpecificityABSTRACT
The current BacT/ALERT SA (BTA SA) aerobic blood culture bottle is made from glass, does not require venting, and contains a liquid emulsion sensor (LES). Its performance has been shown to be equivalent to that of the vented standard aerobic culture bottle. A further-improved version of the BTA SA bottle, designated the BacT/ALERT plastic SA (BTA PSA) culture bottle, is made from clear plastic to prevent breakage, does not require venting, and contains a modified LES (LES 2) to reduce the possibility of false positives. The BTA PSA provides a practical alternative to the current glass version of this bottle. The plastic bottle is also comparable to the current glass bottle in transparency and growth performance and additionally minimizes the exposure to infectious agents due to glass bottle breakage.
Subject(s)
Bacteremia/diagnosis , Bacteremia/microbiology , Fungemia/diagnosis , Fungemia/microbiology , Plastics , Reagent Kits, Diagnostic , Aerobiosis , Bacteria, Anaerobic/growth & development , Bacteria, Anaerobic/isolation & purification , Bacteriological Techniques/instrumentation , Culture Media , Fungi/growth & development , Fungi/isolation & purification , Gram-Negative Bacteria/growth & development , Gram-Negative Bacteria/isolation & purification , Gram-Positive Bacteria/growth & development , Gram-Positive Bacteria/isolation & purification , HumansABSTRACT
The current BacT/Alert standard aerobic (VA) blood culture bottle was redesigned and designated a nonvented aerobic (NVA) culture bottle; this bottle does not require venting. A total of 3,873 sets of blood samples for culture were obtained from adult patients with suspected bacteremia or fungemia. The NVA bottle showed performance equivalent to that of the VA bottle for recovery and speed of detection of microorganisms from blood without the need for venting the bottle.
Subject(s)
Bacteremia/diagnosis , Bacteria/growth & development , Bacteriological Techniques/instrumentation , Blood/microbiology , Fungemia/diagnosis , Fungi/growth & development , Adult , Bacteremia/microbiology , Bacteria/isolation & purification , Fungemia/microbiology , Fungi/isolation & purification , Gram-Positive Bacteria/growth & development , Gram-Positive Bacteria/isolation & purification , HumansABSTRACT
The authors study the Pancreas divisum's rate in 242 cadavers. With two successive studies, they establish a rate of about 6.6%. They conform the sexual disparity and the presence of muscular fibre cells on a level with papilla duodeni minor.
