Objectives: Broad-range PCR has the potential to detect virtually any bacterial species via amplification and nucleotide sequencing of a DNA region common to all bacteria. We aimed to evaluate its usefulness and clinical relevance when applied to a wide variety of primary sterile materials. Methods: A prospective study including 1370 samples (75 heart valves, 151 joint tissue samples, 230 joint aspirates, 848 whole blood samples and 66 culture-negative cerebrospinal fluid samples) were studied by using a commercial PCR system for detecting 16S rDNA (Molzym). The PCR results were compared with culture and were considered to provide added diagnostic value only if the PCR approach revealed new pathogens that were missed by culture. Results: The added value of PCR was evident in 173 of 555 PCR-positive samples (0.126; 0.109e0.144 (proportion from all tested samples; 95% confidence interval)), most frequently in examinations of heart valves (0.56; 0.448e0.672) and joint tissue samples (0.219; 0.153e0.284). In contrast, the lowest rate of PCR with added value was noted for blood samples, regardless of the patient cohort they had been drawn from (nononcologic patients from intensive care: 0.065; 0.043e0.087, haematooncologic children: 0.048; 0.027e0.070). Moreover, PCR missed up to 7.1% of blood culture findings (0.071; 0.048e0.095) regarded as clinically relevant, which was the second highest failure rate after joint tissue samples (0.099; 0.052e0.147). Conclusions: Broad-range PCR substantially increases detection rate of pathogens, especially from heart valves and joint samples. However, a concurrent risk of false-negative PCR results justifies the need for parallel culture.
Background: In order to estimate the prevalence of plasmid borne colistin resistance and to characterize in detail the mcr-positive isolates, we carried out a sentinel testing survey on the intestinal carriage of plasmid-mediated colistin-resistant Enterobacteriaceae in hospitalized patients. Methods: Between June 2018 and September 2019, 1922 faecal samples from hospitalised patients were analysed by selective culture in presence of colistin (3.5 mg/L), and in parallel by direct detection of the mcr-1 to mcr-8 genes by qPCR. The mcr-positive isolates were characterised by whole-genome sequencing. Results: The prevalence of the mcr-1 gene was 0.21% (n = 4/1922); the mcr-2 to 8 genes were not detected. The mcr-1 gene was found to be localised in the IncX4 (n = 3) and IncHI2 (n = 1) plasmid type. One Escherichia coli isolate was susceptible to colistin due to the inactivation of the mcr-1 gene through the insertion of the IS2 element; however, the colistin resistance was inducible by culture in low concentrations of colistin. One human mcr-1 positive E. coli isolate was related genetically to the mcr-1 E. coli isolate derived from turkey meat of Czech origin. Conclusions: mcr-mediated colistin resistance currently poses little threat to patients hospitalised in Czech healthcare settings. The presence of the mcr-1 gene in the human population has a possible link to domestically produced, retail meat.
Summary
Bacillary angiomatosis (BA) is a disorder of neovascular proliferation involving skin and other organs of immunosuppressed patients caused by Bartonella species. BA has been recognized in both immunocompetent and immunodeficient patients, mostly in human immunodeficiency virus (HIV)‐infected persons, much more rare in those with other immunodeficiencies, including organ transplantation. Diagnosis is based on serologic analysis, culture and molecular biology [detection of Bartonella species deoxyribonucleic acid (DNA) in tissue biopsy extracts by real‐time polymerase chain reaction (PCR)]. All immunosuppressed patients with BA should be treated with antibiotics because of potentially life‐threatening course of the disease. We report the first case of cutaneous bacillary angiomatosis due to Bartonella quintana in renal transplant recipient. This presentation demonstrates that BA should be considered a differential diagnosis in immunocompromised patients presenting with fever and cutaneous angioma‐like lesions.
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