Controlled clinical comparison of new pediatric medium with adsorbent polymeric beads (PF Plus) versus charcoal-containing PF medium in the BacT/alert blood culture system.

We conducted a controlled clinical comparison of PF Plus, the new pediatric medium with adsorbent polymeric beads, versus the charcoal-containing PF medium in the BacT/Alert blood culture system. A total of 2,381 pediatric cultures were enrolled, and 1,703 (71.5%) were deemed to be compliant and acceptable for analysis. Seventy-two cultures (4.2%) had a positive result with 80 clinically significant microorganisms. The results showed that the PF Plus medium yielded more clinically significant microorganisms than the BacT/Alert system (P < 0.05). In addition, the PF Plus bottle yielded positive results an average of 5.0 h earlier than the PF bottle for compliant clinically significant cultures (18.3 h versus 23.2 h, P = 0.004). PF Plus is an improved medium for detecting microorganisms that cause pediatric bloodstream infections.

Klebsiella pneumoniae Carbapenemase-producing Enterobacteriaceae, Northeast Florida.

BACKGROUND: Since 2001 there have been several reported outbreaks due to carbapenem-resistant Klebsiella pneumoniae (Kp), particularly in the northeastern states. METHODS: Carbapenemase-producing Enterobacteriaceae from healthcare facilities in Northeast Florida were phenotypically identified and confirmed using PCR amplification and sequencing of the blaKPC gene. RESULTS: Results from PFGE analysis of these isolates demonstrated possible horizontal spread from two possible "outbreak" strains during the study period. CONCLUSIONS: We present the first published cluster of Kp and Escherichia coli (Ec) cases in Florida carrying the KPC-2 or KPC-3 gene.

A multi-laboratory comparison of two molecular methods for the detection of toxigenic Clostridium difficile.

INTRODUCTION: Diarrheal disease due to toxigenic Clostridium difficile (CD) accounts for an increased number of hospitalizations and deaths each year. Published guidelines recommend reflex testing of CD antigen-positive samples to molecular testing or testing samples directly by a molecular assay. This multicenter study was designed to compare the accuracy of two different molecular methods targeting different CD genes: Xpert C. difficile Epi RUO RT-PCR assay (XPCR) which targets toxin B (Cepheid, Sunnyvale, CA) and a laboratory-developed PCR (LDPCR) which targets mutations in the tcdC regulatory gene. METHODOLOGY: Two molecular methods for toxigenic CD detection, the Xpert C. difficile Epi RUO RT-PCR assay (XPCR) [Cepheid, Sunnyvale, CA] and a laboratory-developed PCR assay (LDPCR) were compared to a consensus gold standard (CGS) or toxigenic culture (TC) as the reference method. A subset of specimens was subjected to additional molecular characterization of toxigenic CD. RESULTS: Both molecular methods were >90% sensitive for CD detection. Discordant results were noted when molecular test results were compared to non-molecular methods. Supplemental molecular characterization illustrated inherent difficulties in comparisons using different molecular methods for CD. CONCLUSION: Laboratories may consider using multiple CD detection methods or combinations of methods, including molecular detection for rapid and accurate diagnosis of CD, as driven by best practices for the respective healthcare environment. Laboratories must be aware of intrinsic differences when comparing performance characteristics of different molecular assays.

Antimicrobial susceptibility among Acinetobacter calcoaceticus-baumannii complex and Enterobacteriaceae collected as part of the Tigecycline Evaluation and Surveillance Trial.

OBJECTIVE: To measure the in vitro activity of a panel of antimicrobial agents against gram-negative pathogens collected from the nine census regions of the USA. METHODS: Isolates were collected from 76 centers between January 2004 and September 2005. In vitro activity was assessed using CLSI guidelines and CLSI or FDA interpretive criteria. RESULTS: The lowest overall antimicrobial susceptibilities for Acinetobacter calcoaceticus-baumannii complex isolates (n=851) were detected in the Middle Atlantic and East South Central regions. Overall, 29.3% of A. calcoaceticus-baumannii complex isolates were multidrug-resistant (resistant to > or =3 antimicrobial classes). Tigecycline (2 microg/mL) had the lowest MIC90 against this organism. Imipenem, tigecycline, and levofloxacin had low MIC90s (0.25-4 microg/mL) against Enterobacter spp. (n=1557), although the MIC90 for levofloxacin was elevated for East South Central region isolates (> or = 16 microg/mL). Susceptibility to levofloxacin among the E. coli isolates (n=1785) ranged from 71.7% (Pacific) to 88.5% (New England). The prevalence of ESBL-producing K. pneumoniae (126/1460) varied from 1.7% of isolates (Pacific) to 21.2% (Middle Atlantic). ESBL-producing K. pneumoniae MICs were lowest for imipenem and tigecycline. CONCLUSIONS: Antimicrobial susceptibility varies among the census regions of the USA. The broad-spectrum in vitro activity of tigecycline may make it a suitable candidate for use in the empiric treatment of serious infections.