Point-of-Care Testing for Clostridium Difficile Infection: A Real-World Feasibility Study of a Rapid Molecular Test in Two Hospital Settings

Abstract

IntroductionIn the developed world, Clostridium difficile infection (CDI) is the most important cause of nosocomial infectious diarrhea. In addition to providing epidemiological data and helping to indicate that a local outbreak may be occurring, laboratory tests are used to augment clinical decisions on individual patients. Very rarely do diagnostic tests provide results at the point of decision making; in the intervening period between requesting investigations on a patient with suspected CDI and return of the laboratory result, decisions must be made regarding patient isolation and treatment.MethodsA 22-month, real-world feasibility study was conducted in patients with clinically significant diarrhea, in a London Hospital between March 2011 and January 2013, in three older persons’ wards and two intensive care units (ICUs) to determine acceptability, ease of use, change in turnaround time and clinical utility of a rapid, polymerase chain reaction (PCR)-based point-of-care test (POCT) (Cepheid GeneXpert®, Sunnyvale, California, USA) for diagnosis of Clostridium difficile. Nurses in the older persons’ ward and laboratory technicians in the ICU were trained to perform the test. Residual samples were sent to the centralized laboratory for parallel testing using a two-step algorithm.ResultsA total of 335 samples were tested using the POCT with a median turnaround time of 1.85 h compared with 18 h for the centralized laboratory test. Overall agreement with centralized laboratory testing was 98.1%. Discrepant samples were more frequent on elderly wards than ICU. Overall 20/335 (6%) processing errors were encountered and were highest in the first few months of the study. Significantly more processing errors occurred on the older persons’ wards 13/102 (12.7%) than on ICU 7/271 (2.6%). Older persons’ patients who had POCT were significantly less likely to have a test requested for bacterial stool culture (3.1% vs. 10.9% p = 0.044). This difference was not observed in the ICU patients. No other differences in ancillary test requesting, mortality or length of stay were observed.ConclusionsThe majority of users reported that the POCT was easy to perform and was an acceptable part of their job. POCT using this system is feasible and acceptable to nursing staff and technicians working within these two hospital-based settings.Electronic supplementary materialThe online version of this article (doi:10.1007/s40121-014-0038-6) contains supplementary material, which is available to authorized users.

Point-of-care testing by healthcare workers for detection of meticillin-resistant Staphylococcus aureus, Clostridioides difficile, and norovirus

“…This study provides evidence that rural hospitals without microbiology or virology laboratories can improve their CTATs for MRSA, C. difficile, and norovirus by using POCT methods. One strength of the study is that testing was solely conducted by HCWs rather than by laboratory-trained staff, as has been the case in previous studies [15,16]. The most common test carried out was SA Nasal Complete, which had a sensitivity of 100.00% for MRSA detection, similar to findings from previously reported POCT studies [17e21].…”

“…As a proof-of-concept study we have shown that POCT-PCR, used solely by HCWs, could be used as an alternative screening test to laboratory GDH for C. difficile detection. A recent feasibility study focusing on the assessment of Cepheid GeneXpert for diagnosis of C. difficile on three wards and two intensive care units (ICUs) in a city hospital operated by laboratory technicians found an overall agreement with central laboratory testing to be 98.1% and the median turnaround time was 1.85 h for Xpert C. difficile results compared to 18 h for the central laboratory test [16]. Likewise our study showed good agreement with laboratory testing (99.0% agreement) and the use of Xpert C. difficile assay reduced CTATs; in our case the median CTAT for C. difficile detection using traditional methods (GDH and toxin) was 84 h and this decreased to 3 h using POCT-PR (P < 0.05).…”

The Point-of-Care Laboratory in Clinical Microbiology

“…The rapid detection of C. difficile toxins A and B should be routinely performed for both outpatients and hospitalized patients by using one of the commercially available ICTs, with a specificity of Ͼ99.5% and an average sensitivity of 90% (52). Alternatively, C. difficile, its toxin B, and an additional binary toxin can be detected within 90 min by using commercially available RT-PCR assays such as GeneXpert, with 98% agreement with reference testing in the core laboratory and higher sensitivity than ICTs (53,54). The recent implementation of fecal transplant treatment has changed the prognosis of this infection, making early diagnosis even more important (51).…”

Diagnóstico rápido de las infecciones del tracto gastrointestinal por parásitos, virus y bacterias

“…Existen diferentes PCR en tiempo real, que permiten detectar C. difficile, la toxina B, y la toxina binaria en 90 min. GeneXpert presenta un 98% de acuerdo con la prueba de referencia y mayor sensibilidad que la ICT 4,30 . Sin embargo, una muestra puede ser positiva mediante método molecular y negativa mediante EIA y cultivo celular, por lo que pueden surgir dudas del significado clínico 2,27 .…”

“…Se pueden utilizar: 1) EIA Stx, que permiten detectar, y en algunos casos diferenciar, stx1 y stx2, a partir de un caldo enriquecido incubado una noche a 37 • C, tanto de ECTS O157 como no-O157, y 2) técnicas moleculares, que detectan los genes stx1 y stx2 directamente de las heces, y que es el método más sensible 2 . Recientemente se ha publicado la utilización de una nueva ICT realizada directamente en muestras de heces con excelentes resultados 30 .…”