Improved diagnosis of gastrointestinal infections using a semi-automated multiplex real-time PCR for detection of enteropathogens.

Introduction. The identification of enteropathogens is critical for the clinical management of patients with suspected gastrointestinal infection. The FLOW multiplex PCR system (FMPS) is a semi-automated platform (FLOW System, Roche) for multiplex real-time PCR analysis.Hypothesis/Gap Statement. FMPS has greater sensitivity for the detection of enteric pathogens than standard methods such as culture, biochemical identification, immunochromatography or microscopic examination.Aim.The diagnostic performance of the FMPS was evaluated and compared to that of traditional microbiological procedures.Methodology. A total of 10 659 samples were collected and analysed over a period of 7 years. From 2013 to 2018 (every July to September), samples were processed using standard microbiological culture methods. In 2019, the FMPS was implemented using real-time PCR to detect the following enteropathogens: Shigella spp., Salmonella spp., Campylobacter spp., Giardia intestinalis, Entamoeba histolytica, Blastocystis hominis, Cryptosporidum spp., Dientamoeba fragilis, adenovirus, norovirus and rotavirus. Standard microbiological culture methods (2013-2018) included stool culture, microscopy and immunochromatography.Results. A total of 1078 stool samples were analysed prospectively using the FMPS from July to September (2019): bacterial, parasitic and viral pathogens were identified in 15.3, 9.71 and 5.29 % of cases, respectively. During the same period of 6 years (2013-2018), the proportion of positive identifications using standard microbiological methods from 2013 to 2018 was significantly lower. A major significant recovery improvement was observed for all bacteria species tested: Shigella spp./enteroinvasive Escherichia coli (EIEC) (P <0.05), Salmonella spp. (P <0.05) and Campylobacter spp. (P <0.05). Marked differences were also observed for the parasites G. intestinalis, Cryptosporidium spp. and D. fragilis.Conclusion. These results support the value of multiplex real-time PCR analysis for the detection of enteric pathogens in laboratory diagnosis with outstanding performance in identifying labile micro-organisms. The identification of unsuspected micro-organisms for less specific clinical presentations may also impact on clinical practice and help optimize patient management.

Evaluation of a multiplex panel for the diagnosis of acute infectious diarrhea in immunocompromised hematologic patients.

INTRODUCTION: Diarrhea is a frequent complication in hematologic patients, being an infectious cause frequently suspected. Rapid and accurate detection of gastrointestinal pathogens is vital in immunocompromised hosts. The aim of this study was to compare routine diagnostic methods versus a multiplex polymerase chain reaction (PCR) assay for the diagnosis of infectious diarrhea in immunocompromised hematologic patients. MATERIAL AND METHODS: We conducted a prospective observational study from March 2015 to January 2016 to compare conventional methods for the diagnosis of infectious diarrhea with FIlmArray GI Panel (BioFire-bioMérieux, France). Samples from adult immunocompromised hematologic patients with acute diarrhea were collected. In cases with discordant results, a second multiplex assay was performed (Allplex, Seegene, Korea). The result was considered positive or negative when the same result was obtained by at least two of the methods. RESULTS: A total of 95 samples were obtained from 95 patients (median age of 52 years (46-64)). Sixty-one (64%) episodes were hospital-acquired and 34 (36%) were community-acquired diarrhea. Twenty-five (26%) patients had a positive microbiological result, being Clostridium difficile the most frequent pathogen, followed by Campylobacter spp and norovirus. The concordance between FilmArray methods was good (k = 0.79). The FilmArray GI panel showed a sensitivity of 95%, a specificity of 100% for positive results. The time required to obtain results was markedly reduced with the use of multiplex PCR methods. CONCLUSIONS: Multiplex molecular panels provide a rapid and sensitive tool for the diagnosis of infectious diarrhea, thereby allowing more timely clinical decisions in immunocompromised hematologic patients.

Rare diagnosis of nodular lymphangitis caused by Mycobacterium marinum: MDCT imaging findings.

Mycobacterium marinum is an atypical mycobacterium that usually causes a solitary nodule on the hand ("fish tank granuloma") or less commonly, secondary erythematous channels and nodules spread along lymphatic drainage of the extremity, mimicking sporothricoid skin lesions of nodular lymphangitis. This report presents a case of this rare entity, a nodular lymphangitis caused by Mycobacterium marinum. Multidetector computed tomography (MDCT) imaging was very useful in determining the morphology (cellulitis with a few small subcutaneous nodules and channels) and the extension of the lesion.

[Burkholderia cepacia bacteremia: a prospective analysis of 33 episodes]. / Bacteriemias por Burkholderia cepacia: análisis prospectivo de 33 episodios.

INTRODUCTION: The aim of this study is to describe clinical characteristics and outcome of Burkholderia cepacia bacteraemia, susceptibility of the isolates and differences between cases from epidemic outbreaks and sporadic cases. MATERIAL AND METHODS: From 1993 to 2009, episodes of B. cepacia bacteraemia were prospectively collected in a university hospital. RESULTS: A total of 33 episodes were included, of which 21 were part of two outbreaks (9 in 1994 and 12 in 2006). Outbreak cases had a median age of 58 years, 45% had neoplasia, median length of stay until bacteraemia was 15 d (range 0-120) and 82% had received an antibiotic. The most prevalent sources of bacteraemia were catheter (48%) and unknown (33%). On the other hand, sporadic cases stayed longer until diagnosis (median 25 days versus 11, p=0.041) and showed a trend to have neoplasia more frequently (83% versus 33%, p=0.083). Susceptibility to antibiotics was varied and co-trimoxazole was the only active agent against all strains. CONCLUSIONS: B. cepacia is an uncommon pathogen, which affects patients with prolonged hospitalization and severe comorbidities. The identification of more than one case in a short term of time should raise the suspicion of an outbreak.