- Volume 1, Issue 5, 2019
Volume 1, Issue 5, 2019
- Research Article
-
-
-
Molecular screening of the human parvoviruses B19 and bocavirus 1 in the study of congenital diseases as applied to symptomatic pregnant women and children
Introduction. B19 virus (B19V) and bocavirus 1 (HBoV1) are human pathogenic parvoviruses that are prevalent worldwide and are responsible for a diverse and not yet fully established spectrum of clinical manifestations.
Objective. To screen B19V and HBoV1 in patients with clinical manifestations associated with acquisition of the infection during gestation.
Methods. A retrospective, observational study was performed that included serum samples from patients without a previous known aetiology. B19V and HBoV1 were determined by end-point PCR. Positive samples were genotyped.
Results. A total of 106 serum samples were analysed, 61 from pregnant women and 45 from neonates and paediatric patients. None were positive for HBoV1, while B19V was detected in 37/106 [34.9 %, 95 % confidence interval (CI): 26.5–44.4] of the samples studied. In the group of pregnant women, 28/61 (45.9 %, 95 % CI: 34.0–58.3) were B19V-positive, and 2 of them had foetal anaemia followed by hydrops and foetal death, 3 were associated with a history of recurrent pregnancy loss and there was 1 case of spontaneous abortion. B19V was also detected in cases of maternal febrile exanthema, polyhydramnios, oligohydramnios and foetal ascites. In the group of children, 9/45 (20.0 %, 95 % CI: 10.9–33.8) neonatal patients were B19V-positive, and this was associated with foetal hydrops, TORCH syndrome and cardiac alterations. The nucleotide sequences analysed confirmed the identity of B19V genotype 1.
Conclusions. We found no evidence to indicate the presence of HBoV1 in maternal blood or in the newborns/paediatric patients (hence providing no support for the supposed vertical transmission). On the other hand, the high frequency of B19V in the pathologies studied indicates the importance of molecular diagnosis in both the mother and the child. Future efforts should contribute to early detection and characterization of infections.
-
-
-
-
Expression of Escherichia coli araE and modified lacY genes in Campylobacter jejuni is not sufficient for arabinose transport
More LessIntroduction. Unlike Escherichia coli , Campylobacter jejuni is unable to import a range of sugars, including arabinose, which makes common expression vectors, such as pBAD33, non-functional in these bacteria.
Aim. The aim of this study was to investigate whether the E. coli transporters AraE and modified LacY (LacYA177C) would enable C. jejuni to uptake arabinose.
Methodology and Results. The respective genes of E. coli were constitutively expressed in C. jejuni strain 11168H after integration into the chromosome via homologous recombination. Vectors carrying these genes also contained a reporter gene, gfp, under the control of the arabinose-inducible promoter, pBAD. These constructs were verified in E. coli by demonstrating the induction of gfp in the presence of arabinose. Integration of the genes into one of the rRNA gene clusters was verified by PCR and genome sequencing. The latter also confirmed that the inserted gene clusters contained no mutations. Expression of the gfp gene in the presence of arabinose inducer was monitored using fluorescence microscopy of colonies and fluorimetry using both whole cells and lysates.
Conclusion. The results demonstrated the inability of C. jejuni to use arabinose transporters, which are fully functional in E. coli , suggesting a remarkable difference in the physiology of these bacteria.
-
- Short Communication
-
-
-
Evaluation of the RESIST-4 O.K.N.V immunochromatographic lateral flow assay for the rapid detection of OXA-48, KPC, NDM and VIM carbapenemases from cultured isolates
More LessPurpose This study aimed to evaluate the performance of the RESIST-4 O.K.N.V immunochromatographic lateral flow assay for the detection of OXA-48, KPC, NDM and VIM carbapenemases in 100 clinical Enterobacteriaceae isolates using solid culture media.
Methodology In total, 100 clinical Enterobacteriaceae isolates with characterized β-lactamase enzymes (OXA-48 n=46, KPC n =4, NDM n =43 and VIM n =10) were evaluated using the RESIST-4 O.K.N.V assay. The assay was also evaluated using carbapenem-sensitive control strains and confirmed non-carbapenemase-producing Enterobacteriaceae clinical isolates resistant to carbapenems. Inter-rater agreement of the test was evaluated by four different users who tested 11 randomly selected isolates daily over 3 days.
Results Overall accuracy of the assay was 99.5 %. For the detection of KPC, OXA-48 and its variants and VIM the assay correctly identified 100 % of the isolates when compared to PCR. Initial performance for NDM detection was sensitivity=95.3 %, specificity=100 %. Two PCR positive Providencia rettgeri isolates rendered false negative results on the assay. Retesting from a carbapenem zone of inhibition rendered a positive result for both isolates increasing the sensitivity to 100 %. No false positive results or cross reactions were detected.
Conclusion The RESIST-4 O.K.N.V is reliable, sensitive and specific for the detection of OXA-48, KPC, NDM and VIM carbapenemases. Further evaluation on improving NDM detection in organisms from the Proteeae tribe is warranted to determine optimal test conditions.
-
-
-
-
Microbiome digital signature of MCR genes – an in silico approach to study the diversity of methanogenic population in laboratory-developed and pilot-scale anaerobic digesters
The production of biogas by anaerobic digestion (AD) of organic/biological wastes has a firm place in sustainable energy production. A simple and cost-effective anaerobic jar at a laboratory scale is a prerequisite to study the microbial community involved in biomass conversion and releasing of methane gas. In this study, a simulation was carried out using a laboratory-modified anaerobic-jar-converted digester (AD1) with that of a commercial/pilot-scale anaerobic digester (AD2). Taxonomic profiling of biogas-producing communities by means of high-throughput methyl coenzyme-M reductase α-subunit (mcrA) gene amplicon sequencing provided high-resolution insights into bacterial and archaeal structures of AD assemblages and their linkages to fed substrates and process parameters. Commonly, the bacterial phyla Euryarchaeota , Chordata, Firmicutes and Proteobacteria appeared to dominate biogas communities in varying abundances depending on the apparent process conditions. Key micro-organisms identified from AD were Methanocorpusculum labreanum and Methanobacterium formicicum . Specific biogas production was found to be significantly correlating to Methanosarcinaceae . It can be implied from this study that the metagenomic sequencing data was able to dissect the microbial community structure in the digesters. The data gathered indicates that the anaerobic-jar system could throw light on the population dynamics of the methanogens at laboratory scale and its effectiveness at large-scale production of bio-methane. The genome sequence information of non-cultivable biogas community members, metagenome sequencing including assembly and binning strategies will be highly valuable in determining the efficacy of an anaerobic digester.
-
- Case Report
-
-
-
First report of peritonitis caused by the vancomycin-resistant coccus Pediococcus pentosaceus in a patient on continuous ambulatory peritoneal dialysis
Introduction. Worldwide, about one-tenth of end-stage renal disease (ESRD) patients are on peritoneal dialysis (PD). Peritonitis is a major cause of PD failure and change of therapy to haemodialysis. An update on peritoneal dialysis-related infections has recommended the use of a first generation cephalosporin or vancomycin as an empirical therapy for Gram-positive organisms. Pediococcus spp. is a Gram-positive environmental cocci that have been increasingly reported from various nosocomial infections but very rarely from peritoneal dialysis infections. It is intrinsically resistant to Vancomycin but sensitive to ampicillin. So, diagnosis of this bacteria is important if isolated from PD infections.
Case presentation. An elderly female patient of ESRD on continuous ambulatory peritoneal dialysis (CAPD) was admitted with complaints of high fever and cloudy PD effluent for 2 days. She was started with vancomycin and imipenem empirically but did not improve even after 4 days. Pus cells were seen when PD fluid was examined microscopically. BACTEC culture of PD fluid isolated growth of Gram-positive cocci, which was confirmed as Pediococcus pentosaceus . It was resistant to vancomycin. The antibiotic of the patient was changed to ciprofloxacin IV. The patient responded in 2 days and was discharged after 7 days.
Conclusion. This is the first case report of Pediococcus pentosaceus peritonitis in an ESRD patient on CAPD. Accurate diagnosis and antibiotic sensitivity test of the bacteria is important especially if isolated in critical patients as it is intrinsically resistant to vancomycin.
-
-