The prognostic value of toxin B and binary toxin in Clostridioides difficile infection

To study the association between detection of the Clostridioides difficile gene encoding the binary toxin (CDT) and direct detection of toxinB (TcdB) from feces with the appearance of serious disease, complications, or recurrence in a prospective series of cases. A total of 220 confirmed cases were included, using a two-step algorithm: an initial study to detect the enzyme, glutamate dehydrogenase (GDH), followed, in cases of positivity, by detection of the tcdB. tcdB-positive patients were investigated for the presence of CDT and TcdB. Outcome variables were severe disease, the modified Illinois C. difficile infection (CDI) prognostic risk index (ZAR score), the appearance of complications (need for colectomy, CDI-related death, or toxic megacolon) and recurrence. Patients who tested positive for the presence of TcdB in feces were found to have greater disease severity than those who tested negative, with a ZAR score of 35.4% vs. 23% (p = .048), a higher recurrence rate (14.6% vs. 5.9%, p = .032), and a tendency for higher number of complications (20.7% vs. 11.5%), although without reaching statistical significance (p = .053). When presence of CDT was analyzed, higher frequencies of severe disease (39.2% vs. 21.2%, p = .005), complications and recurrence (21.6% vs. 10.9%, p = .037 and 14.9% vs. 5.8%, p = .029; respectively) were observed in patients where CDT was detected. TcdB and CDT act as prognostic markers of the appearance of serious disease, complications or recurrence in cases of CDI. Simultaneous detection of both markers, TcdB and CDT, had a greater impact on the prognosis than when they were detected separately.

A cost-saving strategy for processing isolated uropathogens in community-acquired urinary tract infections

Outpatient urine samples are among the most commonly processed in a microbiology laboratory, which involves a high economic burden. The aim of this study was compare cost and efficiency to process uropathogens between MicroScan system (2010-2011) versus a chromogenic medium and the disk diffusion method (2013-2014). In the first period, a total 9918 bacterial populations were isolated from urine samples. Annual estimated costs during 2010 and 2011 for processing were EUR 53,818 and EUR 57,306, respectively (EUR 111,124 total). In the second period, a total 11,728 bacterial isolates were processed, with annual estimated costs of EUR 21,078 and EUR 23,248, respectively (EUR 44,326 total). We included the cost for a laboratory technician (252h worked per year), estimated at EUR 2500 per year. The mean estimated savings were EUR 66,797 (60%).The identification by chromogenic media and antibiotic susceptibility patterns by disk diffusion method was similar to MicroScan in both study periods. Only some isolated Citrobacter spp., Enterobacter spp., Morganella morganii, and Providencia spp. were misidentified. The strategy reported here did not affect the quality of the results and yielded substantial cost savings.

[Evaluation of the LightCycler® SeptiFast test in newborns and infants with clinical suspicion of sepsis]

INTRODUCTION

Neonatal sepsis is a significant cause of morbidity and mortality. Early diagnosis and prompt antimicrobial therapy are crucial for a favorable outcome of the newborn child. Blood culture, the current "gold standard" method for diagnosing bloodstream infections, has a low sensitivity in newborns. We evaluated the multiplex real-time PCR LightCycler(®) SeptiFast (LC-SF) for detection of bloodstream infections in newborns, compared with conventional blood culture.

METHODS

A total of 42 blood samples were obtained from 35 subjects presenting with a febrile episode and hospitalized in neonatal intensive care unit at Hospital Universitario Virgen de las Nieves. Two samples were collected during each febrile episode in order to carry out LC-SF assay and blood culture, respectively.

RESULTS

Sensitivity and specificity of 79% and 87%, respectively, compared with clinical diagnosis, were obtained for LC-SF. Contamination rate of blood cultures was 16.7%, mainly due to coagulase-negative staphylococci (CoNS) and viridans groups of streptococci. Contamination rate of LC-SF by CoNS was 2.4%. Concordance between LC-SF and blood culture was moderate (kappa index: 0.369). LC-SF demonstrated a higher concordance (kappa index: 0.729) with the final clinical diagnosis than blood culture (kappa index: 0.238).

CONCLUSION

LC-SF assay could be a useful diagnostic tool, along with a conventional blood culture, in newborn, for confirming or ruling out those cases that blood culture could not determine, shortening the time to result to 7 hours.