A k2A-positive Klebsiella pneumoniae causes liver and brain abscess in a Saint Kitt's man

Klebsiella pneumoniae isolated in community-acquired pneumonia is increasingly found in primary pyogenic liver abscesses. The presence of magA in K. pneumoniae has been implicated in hypermucoviscosity and virulence of liver abscess isolates. The K2 serotype has also been strongly associated with hypervirulence. We report the isolation of non-magA, K2 K. pneumoniae strain from a liver abscess of a Saint Kitt's man who survived the invasive syndrome

Evaluation of the LiPA MYCOBACTERIA Assay for Identification of Mycobacterial Species from BACTEC 12B Bottles

The LiPA MYCOBACTERIA (Innogenetics NV, Ghent, Belgium) assay was used to identify mycobacterial isolates using culture fluid from positive BACTEC 12B bottles. The LiPA method involves reverse hybridization of a biotinylated mycobacterial PCR fragment, a 16 to 23S rRNA spacer region, to oligonucleotide probes arranged in lines on a membrane strip, with detection via biotin-streptavidin coupling by a colorimetric system. This system identifies Mycobacterium species and differentiates M. tuberculosis complex, M. avium-M. intracellulare complex, and the following mycobacterial species: M. avium, M. intracellulare, M. kansasii, M. chelonae group, M. gordonae, M. xenopi, and M. scrofulaceum. The mycobacteria were identified in the laboratory by a series of tests, including the Roche AMPLICOR Mycobacterium tuberculosis (MTB) test, the Gen-Probe ACCUPROBE, and a PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of the 65-kDa heat shock protein gene. The LiPA MYCOBACTERIA assay detected 60 mycobacterium isolates from 59 patients. There was complete agreement between LiPA and the laboratory identification tests for 26 M. tuberculosis complex, 9 M. avium, 3 M. intracellulare complex, 3 M. kansasii, 4 M. gordonae, and 5 M. chelonae group (all were M. abscessus) isolates. Three patient samples were LiPA positive for M. avium-M. intracellulare complex, and all were identified as M. intracellulare by the PCR-RFLP analysis. Seven additional mycobacterial species were LiPA positive for Mycobacterium spp. (six were M. fortuitum, and one was M. szulgai). The LiPA MYCOBACTERIA assay was easy to perform, and the interpretation of the positive bands was clear-cut. Following PCR amplification and gel electrophoresis, the LiPA assay was completed within 3 h

Rapid and Specific Detection of Mycobacterium tuberculosis by Using the Smart Cycler Instrument and a Specific Fluorogenic Probe

A procedure using the Smart Cycler instrument and a fluorescence quencher (FQ) probe for the specific identification of Mycobacterium tuberculosis complex (MTB) was used to detect organisms in 366 acid-fast bacillus smear-positive respiratory specimens. It was compared to culture and the AMPLICOR M . tuberculosis PCR test. MTB was isolated from 198 of these samples. The FQ PCR assay was sensitive (197 of 198, 99.5%) and specific (165 of 168, 98.2%); no significant difference was observed between the two PCR protocols. After DNA extraction, a final result was available within 1.5 h with the real-time PCR protocol

Rapid and Specific Detection of Mycobacterium tuberculosis from Acid-Fast Bacillus Smear-Positive Respiratory Specimens and BacT/ALERT MP Culture Bottles by Using Fluorogenic Probes and Real-Time PCR

A real-time PCR assay using the LightCycler (LC) instrument for the specific identification of Mycobacterium tuberculosis complex (MTB) was employed to detect organisms in 135 acid-fast bacillus (AFB) smear-positive respiratory specimens and in 232 BacT/ALERT MP (MP) culture bottles of respiratory specimens. The LC PCR assay was directed at the amplification of the internal transcribed spacer region of the Mycobacterium genome with real-time detection using fluorescence resonance energy transfer probes specific for MTB. The results from the respiratory specimens were compared to those from the Amplicor M. tuberculosis PCR test. Specimens from MP culture bottles were analyzed by Accuprobe and conventional identification methods. MTB was cultured from 105 (77.7%) respiratory AFB smear-positive specimens; 103 of these samples were positive by LC PCR and Amplicor PCR. Two samples negative in the LC assay contained rare numbers of organisms; both were positive in the Amplicor assay. Two separate samples negative by Amplicor PCR contained low and moderate numbers of AFB, respectively, and both of these were positive in the LC assay. There were 30 AFB smear-positive respiratory specimens that grew mycobacteria other than tuberculosis (MOTT), and all tested negative in both assays. Of the 231 MP culture bottles, 114 cultures were positive for MTB and all were positive by the LC assay. The remaining 117 culture bottles were negative in the LC assay and grew various MOTT. This real-time MTB assay is sensitive and specific; a result was available within 1 h of having a DNA sample available for testing

Superiority of the DNA amplification assay for the diagnosis of C. difficile infection: a clinical comparison of fecal tests

Clostridium difficile infection (CDI) is a major infectious concern, accounting for substantial morbidity and resource utilization. Advances in microbiological and molecular techniques have resulted in an increasing number of testing options for CDI. A glutamate dehydrogenase (GDH) enzyme immunoassay (EIA) and a DNA amplification (DNA-A) test for the diagnosis of CDI have recently become commercially available. The aim of this prospective study was to compare the test performance characteristics of the traditional diagnostic modality for CDI diagnosis, the toxin A/B (TOX) EIA, with those of the GDH EIA and DNA-A test, utilizing enriched toxigenic culture (TGC) as the gold standard. Clinical variables predictive of CDI were also studied. Participants fulfilled one or more criteria placing them at increased risk for CDI. Each stool sample was tested by each of the methods mentioned above. Clinical data parameters were collected via a 12-month review of the electronic medical record prior to the index date of the first stool test. A total of 272 stool samples from 144 admissions of 139 patients were evaluated for CDI. The sensitivity and positive predictive value (PPV) of the TOX EIA were 86.1 and 58.4 %, respectively, whereas the sensitivity and PPV of the GDH EIA and DNA-A test were 100 %. 1.8 % of the GDH tests yielded inconclusive results. Using TGC as the gold standard, nosocomial exposure with emphasis on nursing home residence, history of previous CDI, and female gender were predictive of CDI. Test performance characteristics of the DNA-A test and GDH EIA were superior to those of the traditional TOX EIA. The GDH test is limited by inconclusive test results and requires a multi-step diagnostic algorithm. Therefore, the DNA-A test should be implemented as the diagnostic method of choice for CDI. CDI clinical predictors are important for diagnostic decision-making

Rapid and specific detection of the Mycobacterium tuberculosis complex using fluorogenic probes andreal-time PCR

A rapid and sensitive strategy for the specific identification of Mycobacterium tuberculosis (TB) was designed and evaluated using crude mycobacterial lysates. The speed of real-time polymerase chain reaction (PCR) was combined with the sensitivity of fluorogenic probes to confirm the presence of mycobacteria as well as specifically identify the presence of members of the mycobacteria tuberculosis complex (MTC) in a single-tube assay. Oligonucleotides were designed to amplify the internal transcribed spacer (ITS) from several mycobacterial species. Specific fluorogenic probes were included in the PCR reaction for the identification of TB as well as Mycobacterium bovia and Mycobacterium africanum in bacterial lysates. The combination of TB-specific fluorogenic probes with real-time PCR formed an approach determined to be fast (less than 40 min), sensitive (less than 800 copies of DNA) and reliable for the specific detection of the MTC. Our data demonstrate the use of real-time PCR and fluorogenic probes in a rapid and sensitive assay to distinguish members of the MTC from other mycobacterial species

A k2A-positive Klebsiella pneumoniae causes liver and brain abscess in a Saint Kitt's man

Klebsiella pneumoniae isolated in community-acquired pneumonia is increasingly found in primary pyogenic liver abscesses. The presence of magA in K. pneumoniae has been implicated in hypermucoviscosity and virulence of liver abscess isolates. The K2 serotype has also been strongly associated with hypervirulence. We report the isolation of non-magA, K2 K. pneumoniae strain from a liver abscess of a Saint Kitt's man who survived the invasive syndrome.</p