Shortening identification times: comparative observational study of three early blood culture testing protocols.

Background: While early appropriate antibiotic therapy is a proven means of limiting the progression of infections, especially bacteremia, empirical antibiotic therapy in sepsis is ineffective up to 30%. The aim of this study was to compare early blood culture testing protocols in terms of their ability to shorten the delay between blood sampling and appropriate antibiotic therapy. Methods: In this french observational study, we compared three blood culture testing protocols. Positive blood cultures were tested using either GenMark ePlex panels (multiplex PCR period), a combination of MRSA/SA PCR, ß-Lacta and oxidase tests (multitest period), or conventional identification and susceptibility tests only (reference period). Conventional identification and susceptibility tests were performed in parallel for all samples, as the gold standard. Results: Among the 270 patients with positive blood cultures included, early and conventional results were in good agreement, especially for the multitest period. The delay between a blood culture positivity and initial results was 3.8 (2.9-6.9) h in the multiplex PCR period, 2.6 (1.3-4.5) h in the multitest period and 3.7 (1.8-8.2) h in the reference period (p<0.01). Antibiotic therapy was initiated or adjusted in 68 patients based on early analysis results. The proportion of patients receiving appropriate antibiotic therapy within 48 h of blood sampling was higher in the multiplex PCR and multitest periods, (respectively 90% and 88%) than in the reference period (71%). Conclusion: These results suggest rapid bacterial identification and antibiotic resistance tests are feasible, efficient and can expedite appropriate antibiotic therapy.

[Evaluation of the performance of Cepheid® GeneXpert MRSA/SA Blood Culture assay and results' extrapolation to coagulase-negative staphylococci]. / Évaluation des performances du test GeneXpert MRSA/SA Blood Culture de Cepheid® et extrapolation des résultats aux staphylocoques à coagulase négative.

In hospitalized patients, staphylococcal blood infection is common and mortality is high. Rapid diagnosis using molecular assay aims to identify the presence of Staphylococcus aureus and its resistance to methicillin as soon as the blood culture is positive. We evaluate performance of GeneXpert MRSA/SA Blood Culture assay (Cepheid®) before and after interpretation of the positivity levels of the various probes estimated by the Cycle threshold (Ct), as well as its contribution to the characterization of coagulase-negative staphylococci blood cultures not offered by the supplier. The study involved 145 samples with gram-positive cocci bacteremias. Ct analysis of the different probes revealed a few positive results with very high Ct values distants from the mean. The reclassification of these results as negative improves the specificity of the probes (spa: 100% vs. 96,8% and mec 100% vs. 91,9%) without degrading the sensitivity (spa: 98,1% vs. 100% and mec 98,6% vs. 98,6%). Then, based on an algorithm integrating the amplification results of each target, we extrapolated the results to the coagulase-negative staphylococci. In the end, reclassifying probes with extreme Ct values as negative and using the algorithm for coagulase-negative staphylococci resulted in a 97,9% (142/145) agreement between the molecular assay conclusion and conventional culture.

[Severe acute syphilitic hepatitis]. / Hépatite aiguë sévère d'origine syphilitique.

We report the case of a 23-year-old patient with very marked hepatic cytolysis (ASAT: 18N; ALAT: 44N) associated with biological icterus and mucocutaneous jaundice. Initially, no etiology was identified due to the absence of toxic consumption, the negativity of hepatotropic virus serologies and tests for autoimmune pathologies. Following the appearance of cutaneous signs three weeks after the onset of hepatic involvement, a syphilis serology was performed, which proved positive and led to the diagnosis of secondary syphilis. To our knowledge, only one case of hepatic syphilis with such intense hepatic cytolysis has been described. Usually, the hepatic damage is moderate, with transaminases not exceeding 5 times normal values. Syphilitic hepatitis is rare and occurs in less than 10% of syphilis cases. This case makes it possible to identify syphilis as a neglected etiology of acute hepatitis which should be considered in a context suggestive of infection even in the absence of skin signs.

A rapid and inexpensive protocol to screen for third generation cephalosporin-resistant and non-fermenting Gram-negative rods directly in positive blood cultures.

Third generation cephalosporins are frequently used in the first-line treatment of Gram-negative rod (GNR) bacteremia but are unsuitable in the case of extended-spectrum-beta-lactamase-producing Enterobacterales (ESBL-E) or non-fermenting GNR infections. The aim of this study was to develop and evaluate a simple and rapid two-test protocol involving oxidase and ß-Lacta tests performed directly on positive blood culture broth as a preliminary screen for non-fermenting or third generation cephalosporins-resistant GNR. The diagnostic performance of this approach was evaluated on 294 bottles for the oxidase test and 267 bottles for the ß-Lacta Test. The sensitivity and specificity of the oxidase test were respectively 93.1% and 100%, and the sensitivity of the ß-Lacta Test for ESBL-E was 100% and the specificity 99.5%. This simple protocol, which can be implemented in all laboratories and performed in only 20 min, may be a valuable tool to optimize first-line antibiotic therapy for bacteremia.

ISAba1-dependent overexpression of eptA in clinical strains of Acinetobacter baumannii resistant to colistin.

BACKGROUND: Colistin resistance in Acinetobacter baumannii often results from mutational activation of the two-component system PmrAB and subsequent addition of phospho-ethanolamine (pEtN) to lipooligosaccharide by up-regulated pEtN transferase PmrC. OBJECTIVES: To characterize mechanisms of colistin resistance independent of PmrCAB in A. baumannii. METHODS: Twenty-seven colistin-resistant A. baumannii were collected from 2012 to 2018. Analysis of operon pmrCAB was performed by PCR and sequencing. Seven strains were investigated further by WGS and whole-genome MLST (wgMLST). RESULTS: Seven out of the 27 selected isolates were found to overexpress eptA, a gene homologous to pmrC, likely as a consequence of upstream insertion of an ISAba1 element. Insertion sites of ISAba1 were mapped 13, 18 and 156 bp ahead of the start codon of eptA in five strains, one strain and one strain, respectively. The finding that the isolates did not cluster together when compared by wgMLST analysis supports the notion that distinct insertion events occurred in close, but different, genetic backgrounds. CONCLUSIONS: Activation of eptA and subsequent addition of pEtN to the cell surface represents a novel mechanism of resistance to colistin in A. baumannii.

A major procalcitonin elevation without sepsis in a metastatic small cell lung carcinoma.

We report the case of a 54-year-old man with metastatic pulmonary neuroendocrine tumor associated with major procalcitonin (PCT) elevation without sepsis. Three lines of antibiotic therapies were successively introduced but had no positive effect on PCT kinetic and disease progression. Under palliative care, increasing of PCT level was constant during the hospitalization, along with major asthenia and pain and metastatic progression. PCT is an excellent biological marker of bacterial infection, both sensitive and specific. Nevertheless, we highlight here the existence of a frequent association between neuroendocrine tumors and elevation of PCT in the absence of sepsis.

Candida albicans and non-Candida albicans fungemia in an institutional hospital during a decade.

Since the outcomes of patients with candidemia is poor and Candida spp. with increased resistance to antifungal therapy may be associated with these results, the emergence of these blood infections caused by non-C. albicans Candida spp. was explored prospectively over a two-year period (2009-2010). Candidemia was defined as the recovery of Candida spp. in culture from a patient's blood sample. The in vitro susceptibility of each isolate to amphotericin B, caspofungin, fluconazole and voriconazole was determined. In addition, characteristics of patients and outcomes were investigated in real-time. The Candida distribution was compared to that observed in a similar study 10 years earlier in the same hospital. A total of 182 patients with candidemia were included in the study. While C. albicans was the most frequently isolated species (n = 102), non-C. albicans Candida spp. included; C. glabrata (n = 32), C. parapsilosis (n = 21), C. tropicalis (n = 13), C. krusei (n = 8), C. kefyr (n = 3), C. lusitaniae (n = 2), C. lipolytica (n = 2), C. famata (n = 1), C. guilliermondii (n = 1), C. inconspicua (n = 1), C. dubliniensis (n = 1), C. sake (n = 1) and C. nivariensis (n = 1). In seven patients, C. albicans was associated with another Candida spp. Surprisingly, this prospective study demonstrated that regardless of the department (intensive care unit or hematological department), Candida spp. distribution was no different from that found in the 1998-2001 survey, except for C. krusei. A reduction in the proportion of C. krusei isolates was observed from 2000-2010 (P = 0.028) as a result of its decreased recovery in the hematological department.