The Evaluation of the Performance of C. Diff Quik Chek Complete and Toxin A + B (Clostridium difficile) DUO Diagnostic Tests Compared with Toxigenic Culture in the Diagnosis of Clostridium difficile Infection.

BACKGROUND: Clostridium difficile is an important cause of nosocomial diarrhea and the best standard laboratory method for the diagnosis of C. difficile infection is controversial. In this study, we aimed to investigate the performance of Toxin A + B (Clostridium difficile) DUO kit which detects C. difficile toxin A and B by the immunochromatographic method and C. Diff Quik Chek Complete (QCC) rapid membrane immunoassay kit which determines the presence of glutamate dehydrogenase (GDH) and C. difficile toxin A and B in stool samples, compared with toxigenic culture in the diagnosis of C. difficile infection. METHODS: One hundred ninety-three stool samples from patients suspected of having C. difficile infection were included in the study. The performances of two commercial tests were compared with toxigenic culture which was accepted as the reference method. RESULTS: The sensitivity and specificity of the GDH component of QCC were 94.4% and 97.7%, the sensitivity and specificity of the toxin component were 92.3% and 100%, respectively. The sensitivity and specificity of Toxin A + B (Clostridium difficile) DUO test were found as 53.8% and 87.8%, respectively. CONCLUSIONS: C. Diff Quik Chek Complete test, which is a rapid test with high sensitivity and specificity, can be used alone for the diagnosis of C. difficile infection while Toxin A + B (Clostridium difficile) DUO test cannot be used for the same purpose due to the low sensitivity and specificity of the test.

Matrix-Assisted Laser Desorption-Ionization Time-of-Flight Mass Spectrometry (MALDI- TOF MS) for Early Identification of Septic Patients.

BACKGROUND: Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a powerful technique for the rapid identification of bacteria from growing colonies in routine cultures. In this study, we evaluated the feasibility of a 5-hour incubation on solid medium after sub-cultivation of positive blood culture broth without any preparation steps in order to speed up the identification of bacteria. METHODS: In addition to standard laboratory protocols, a Columbia agar plate with 5% sheep blood was inoculated with 1 drop from the blood culture broth. After a 5-hour incubation period, a colony from the culture plate was submitted to MALDI-TOF MS. RESULTS: A total of 1351 positive blood cultures (1299 monomicrobial and 51 polymicrobial) were analyzed. When compared to routine identification procedure results for positive blood cultures, 79.3% of isolates were correctly identified to the species level. When manufacturer-recommended score values were taken into account, MALDITOF MS correctly identified 98.4% of the isolates to the species level with a score of > 2.0, 89.1% with a score between 1.7 and 2.0, and 75.4% with a score of < 1.7. CONCLUSIONS: ln our evaluation, a large majority of the S. aureus (91.5%) and Enterobacteriaceae (87.6%) were correctly identified at the species level. A 5-hour incubation period was found to be associated with moderate identification results for CoNS, Enterococcus spp., and nonfermentative gram negative bacilli, with failure being mostly observed with Streptococcus spp., Candida spp., and other gram positive bacteria. We believe that the performance of MALDI-TOF MS identification after short-term culture is directly related to the sufficient growth of microorganisms at 5 hours.

[Investigation of Panton-Valentine leukocidin gene, SCCmec gene cassette types and genotypes of methicillin-resistant Staphylococcus aureus strains isolated from outpatients]. / Ayaktan saglik hizmeti alan hastalardan izole edilen metisiline dirençli Staphylococcus aureus izolatlarinda Panton-Valentin lökosidin geni ve SCCmec gen kaseti tiplerinin arastirilmasi ve izolatlarin genotiplendirilmesi.

The identification of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) is becoming a hard task since colonization with MRSA is lasting for years and the number of the health care facilities other than hospitals is continuously increasing. In this study we aimed to investigate the genetic properties and health-care association of MRSA strains isolated from skin and soft tissue infections of outpatients admitted to Akdeniz University Hospital. Thirty strains were phenotypically identified as MRSA and after assessing the risk factors, 28 (93.3%) of them were classified as health-care associated (HCA) and 2 (6.7%) of them as community-acquired (CA). All of the isolates were positive for nuc and mecA genes by polymerase chain reaction. Antimicrobial resistance rates of HCA-MRSA and CA-MRSA isolates were found as follows, respectively; 89.3% and 0% for rifampin, 89.3% and 50% for ciprofloxacin, 89.3% and 0% for gentamicin, 50% and 50% for erythromycin, 28.6% and 0% for clindamycin, whereas all of the isolates were susceptible to vancomycin, linezolid and trimethoprim-sulfamethoxazole. SCCmec type III was detected in 24 (85.7%) of HCA-MRSA strains. SCCmec type IV was detected in 1 (3.6%) of HCA-MRSA and in 2 (100%) of CA-MRSA strains. Panton-Valentin leucocidin (PVL) gene positivity was detected in only CA-MRSA isolates (2/2; 100%). MRSA isolates were grouped into 17 different genotypes (from A to R) of which pulsotype A was predominant among HCA isolates and CA-MRSA isolates were found to be clonally related with each other. This is the first study which investigated the genetic properties of MRSA strains in Antalya (a province located at Mediterranean Region, Turkey). In this study HCA risk factors were investigated and CA-MRSA rate was only 6.7% among all MRSA strains isolated from outpatients. As a result of detailed investigation of HCA risk factors, it was possible to detect the exact rate of CA-MRSA among outpatients. Thus it is of clinical and epidemiological importance to know the origin of MRSA isolates since this will affect the empirical treatment choice. Genetic studies supplied by appropriate demographic data will help to clarify the evolution and epidemiology of MRSA in the community and in the hospital setting.