A study on viral haemorrhagic fever due to dengue,chikungunya and Crimean Congo haemorrhagic fever virus among patients attending tertiary care hospital in North East India

PurposeThe present study was undertaken with the objective to study the common etiology of Viral Haemorrhagic Fever (VHF) among patients attending tertiary health care centre in NE India and also to study the clinico-demographic profile of such patients. The agents of VHF included in the study were dengue, chikungunya and Crimean Congo haemorrhagic fever (CCHF) virus. The inclusion of CCHF was based on evidence of seroprevalence in livestock (bovine, sheep and goat) in various North Eastern states.Materials and methodsSerum samples were collected from 51 suspected VHF patients. MAC-ELISA was done to detect dengue and chikungunya specific IgM antibody. The samples were also tested by real-time RT-PCR for detection of dengue, chikungunya and CCHF specific nucleic acid. The laboratory and clinico-demographic profile of these patients were noted in detail.ResultsSerum samples of 16 of 51 suspected cases were confirmed to be suffering from VHF. Among these confirmed cases, 12 were diagnosed with dengue haemorrhagic fever, one was diagnosed with chikungunya and three were diagnosed with dengue-chikungunya co-infection. Based on severity, DHF was further classified into- DHF I- (4,26.6%), DHF II (6,40%), DHF III (3,20%) and DHF IV (2,13.3%). There was no CCHFV infection detected in our study. Retro-orbital pain (P ?= ?0.02) and haematocrit level (P ?= ?0.03) were found to be statistically significant.ConclusionsThis study reiterates the fact that CCHF virus infection is still probably absent in human population of NE India and haemorrhagic symptoms, though rare maybe one of the atypical manifestations of chikungunya infection.     

Diagnosis of bloodstream infections from positive blood cultures and directly from blood samples: recent developments in molecular approaches

BackgroundBloodstream infections are a major cause of death with increasing incidence and severity. Blood cultures are still the reference standard for microbiological diagnosis, but are rather slow. Molecular methods can be used as add-on complementary assays. They can be useful to speed up microbial identification and to predict antimicrobial susceptibility, applied to direct blood samples or positive blood cultures.AimTo review recent developments in molecular-based diagnostic platforms used for the identification of bloodstream infections, with a focus on assays performed directly on blood samples and positive blood cultures.SourcesPeer reviewed articles, conference abstracts, and manufacturers' websites.ContentWe give an update on recent developments of molecular methods in diagnosing BSIs. We first describe the currently available molecular methods to be used for positive blood cultures including: a) in situ hybridization-based methods; b) DNA-microarray-based hybridization technology; c) nucleic acid amplification-based methods; and d) combined methods. Subsequently, molecular methods applied directly to whole blood samples are discussed, including the use of nucleic acid amplification-based methods, T2 magnetic resonance-based methods, and metagenomics for diagnosing BSIs.ImplicationsAdvances in molecular-based methods complementary to conventional blood culture diagnostics and antimicrobial stewardship programmes may optimize infection management by allowing rapid identification of pathogens and relevant antimicrobial resistance genes. Rapid diagnosis of the causing microorganism and relevant resistance determinants is important for early administration and modification of appropriate antimicrobial therapy. Ultimately, this may lead to improved quality and cost-effectiveness of health care, as well as reduced antimicrobial resistance selection.     

Comparative evaluation of two rapid Salmonella-IgM tests and blood culture in the diagnosis of enteric fever

Purpose: Enteric fever is a major public health problem in developing countries like India. An early and accurate diagnosis is necessary for a prompt and effective treatment. We have evaluated the diagnostic accuracy of two Rapid Salmonella-IgM tests (Typhidot-IgM and Enteroscreen-IgM) as compared to blood culture in rapid and early diagnosis of enteric fever. Materials and Methods: A total of 2,699 patients’ serum samples were tested by Rapid Salmonella-IgM tests and blood culture. Patients were divided into two groups. Test group—patients with enteric fever and blood culture positives for Salmonella Typhi; and three types of Controls, i.e. patients with non-enteric fever illnesses, normal healthy controls and patients positive for S. Paratyphi- A. In addition to this we have also evaluated the significance of positive Salmonella-IgM tests among blood culture-negative cases. Results: The overall sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the Typhidot-IgM test and Enteroscreen-IgM test considering blood culture as gold standard were 97.29% and 88.13%, 97.40% and 87.83%, 98.18% and 92.03%, 96.15% and 82.27%, respectively. Typhidot-IgM test was found to be significantly more sensitive and specific as compared to Enteroscreen-IgM. Among blood culture-negative patients, Rapid Salmonella-IgM tests detected 72.25% additional cases of enteric fever. Although the Rapid Salmonella-IgM tests are meant to diagnose S. Typhi only, but these tests detect S. Paratyphi- A also. Thirty-eight patients who were blood culture-positive for S. Paratyphi- A were also positive by Rapid Salmonella-IgM tests. Conclusion: Rapid Salmonella-IgM tests offer an advantage of increased sensitivity, rapidity, early diagnosis and simplicity over blood culture.     

Rapid identification of bloodstream bacterial and fungal pathogens and their antibiotic resistance determinants from positively flagged blood cultures using the BioFire FilmArray blood culture identification panel

Background/purposeRapid and accurate identification of pathogens and their antibiotic resistance directly from flagged blood cultures can aid clinicians in optimizing early antibiotic treatment and improve the clinical outcomes, especially in settings associated with high rates of bloodstream infection caused by vancomycin-resistant Enterococci (VRE) and carbapenem-resistant Enterobacteriaceae (CRE). We compared the results of the BioFire FilmArray Blood Culture Identification (BCID) panel with those of conventional methods for identifying the pathogens and their antibiotic susceptibility status.MethodsIn total, 100 randomly selected positive blood cultures (BACTEC Plus Aerobic/F bottles or BACTEC Anaerobic Lytic/10 bottles) were analyzed. The pathogen detection efficiency of FilmArray BCID panel was compared with that of conventional method using MALDI-TOF MS system (Bruker MALDI Biotyper) and susceptibility testing by the Vitek 2 system. The sequencing analysis of antibiotic resistance genes was performed for discrepant results obtained from MALDI Biotyper and Vitek 2.ResultsAmong the 100 positively flagged blood cultures, 94% of FilmArray BCID panel results were consistent with the MALDI Biotyper results. All five VRE isolates positive for vanA/vanB genes, 10 of 12 Staphylococcus species positive for mecA gene, and only one Klebsiella pneumoniae isolate positive for K. pneumoniae carbapenemase gene (bla_KPC) detected in the FilmArray BCID panel were also concordant with results by the results by conventional susceptibility testing/molecular confirmation.ConclusionsThe FilmArray BCID panel results not only demonstrated good correlation with conventional blood culture identification and susceptibility results but also provided results rapidly, especially for the early detection of MRSA, VRE and bla_KPC–mediated CRE.     

Rapid molecular tests for detection of antimicrobial resistance determinants in Gram-negative organisms from positive blood cultures: a systematic review and meta-analysis

BackgroundTimely detection of antimicrobial (cephalosporin/carbapenem) resistance (AMR) determinants is crucial to the clinical management of bloodstream infections caused by Gram-negative bacteria (GNB).ObjectivesTo review and meta-analyse the evidence for using commercially available molecular tests for the direct detection of AMR determinants in GNB-positive blood cultures (PBCs).Data sourcesPubMed, Scopus and ISI Web of Knowledge.Study eligibility criteriaClinical studies evaluating the performance of two major commercial systems, namely the Verigene® and FilmArray® systems, for rapid testing of GNB-PBCs, in comparison with the phenotypic or genotypic methods performed on GNB-PBC isolates.MethodsLiterature search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria and, for meta-analysis of sensitivity and specificity of both systems, bivariate random-effects model.ResultsTwenty studies were identified (3310 isolates) from 2006 to 2019. Nine studies were conducted in East Asia. In 15 studies using phenotypic comparators (1930 isolates), 1014 (52.5%) isolates were Escherichia coli, and 287 (14.9%) of all the isolates displayed AMR phenotypes. In five studies using genotypic comparators (1380 isolates), 585 (42.4%) were E. coli, and 100 (7.2%) of all the isolates displayed AMR genotypes. Pooled sensitivity and specificity estimates for detection of AMR determinants by the Verigene (i.e. CTX-M, IMP, KPC, NDM, OXA and VIM) and/or FilmArray (i.e. KPC) systems were 85.3% (95% CI 79.9%–89.4%) and 99.1% (95% CI 98.2%–99.5%), respectively, across the 15 studies, and 95.5% (95% CI 89.2%–98.2%) and 99.7% (95% CI 99.1%–99.9%), respectively, across the five studies.ConclusionsOur findings show that the Verigene and FilmArray systems may be a valid adjunct to the conventional microbiology (phenotypic or genotypic) methods used to identify AMR in GNBs. The FilmArray system detects only one AMR genotype, namely KPC, limiting its use. Both Verigene and FilmArray systems can miss important cephalosporin/carbapenem resistance phenotypes in a minority of cases. However, the sensitivity and specificity of both systems render them valuable clinical tools in timely identification of resistant isolates. Further studies will establish the prominence of such rapid diagnostics as standard of care in individuals with bloodstream infections.     

Assessment of the BacT/Alert blood culture system: rapid bacterernia diagnosis with loading throughout the 24 h

Objective: To determine blood culture (BC) diagnostic speed when combining an automated BC system with rapid loading of inoculated bottles throughout the 24 h.
Methods: A total of 111 positive BCs representing bacteremia were investigated in retrospect. All bottles were loaded into the BacT/Alert BC system (Organon Teknika) as soon as possible after sampling and time from specimen collection to Gram stain result was recorded.
Results: The mean time from specimen collection to loading was 3.5 h (median 2.1 h). We found that 74% of all positive BCs collected during daytime (08.00–16.00) ere reported (as Gram stain) to the clinician before 17.00 the next day. For specimens collected between 16.00 and midnight the corresponding proportion was 67%. BCs drawn between midnight and 08.00 were reported before 17.00 the same day in 24% of the cases.
Conclusions: Rapid loading of an automated BC system throughout the 24 h results in fast diagnosis of bacteremia. The diagnostic speed in this study represents a fair estimation of the maximal diagnostic speed accomplishable in a clinical situation with the BacT/Alert system in conjunction with normal daytime laboratory working hours.     

Rapid phenotypic methods to improve the diagnosis of bacterial bloodstream infections: meeting the challenge to reduce the time to result

BackgroundAdministration of appropriate antimicrobial therapy is one of the key factors in surviving bloodstream infections. Blood culture is currently the reference standard for diagnosis, but conventional practices have long turnaround times while diagnosis needs to be faster to improve patient care. Phenotypic methods offer an advantage over genotypic methods in that they can identify a wide range of taxa, detect the resistance currently expressed, and resist genetic variability in resistance detection.AimsWe aimed to discuss the wide array of phenotypic methods that have recently been developed to substantially reduce the time to result from identification to antibiotic susceptibility testing.SourcesA literature review focusing on rapid phenotypic methods for improving the diagnosis of bloodstream infection was the source.ContentRapid phenotypic bacterial identification corresponds to Matrix-assisted laser-desorption/ionization time of flight mass spectrometry (MALDI-TOF), and rapid antimicrobial susceptibility testing methods comprised of numerous different approaches, are considered and critically assessed. Particular attention is also paid to emerging technologies knocking at the door of routine microbiology laboratories. Finally, workflow integration of these methods is considered.ImplicationsThe broad panel of phenotypic methods currently available enables healthcare institutions to draw up their own individual approach to improve bloodstream infection diagnosis but requires a thorough evaluation of their workflow integration. Clinical microbiology will probably move towards faster methods while maintaining a complex multi-method approach as there is no all-in-one method.     

Rapid method for direct identification of bacteria in urine and blood culture samples by matrix-assisted laser desorption ionization time-of-flight mass spectrometry: intact cell vs. extraction method

Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is a fast and reliable technology for the identification of microorganisms with proteomics approaches. Here, we compare an intact cell method and a protein extraction method before application on the MALDI plate for the direct identification of microorganisms in both urine and blood culture samples from clinical microbiology laboratories. The results show that the intact cell method provides excellent results for urine and is a good initial method for blood cultures. The extraction method complements the intact cell method, improving microorganism identification from blood culture. Thus, we consider that MALDI-TOF MS performed directly on urine and blood culture samples, with the protocols that we propose, is a suitable technique for microorganism identification, as compared with the routine methods used in the clinical microbiology laboratory.     

Blood culture diagnostics: a Nordic multicentre survey comparison of practices in clinical microbiology laboratories

ObjectivesAccurate and rapid microbiological diagnostics are crucial to tailor treatment and improve outcomes in patients with severe infections. This study aimed to assess blood culture diagnostics in the Nordic countries and to compare them with those of a previous survey conducted in Sweden in 2013.MethodsAn online questionnaire was designed and distributed to the Nordic clinical microbiology laboratories (CMLs) (n = 76) in January 2018.ResultsThe response rate was 64% (49/76). Around-the-clock incubation of blood cultures (BCs) was supported in 82% of the CMLs (40/49), although in six of these access to the incubators around the clock was not given to all of the cabinets in the catchment area, and 41% of the sites (20/49) did not assist with satellite incubators. Almost half (49%, 24/49) of the CMLs offered opening hours for ≥10 h during weekdays, more commonly in CMLs with an annual output ≥30 000 BCs. Still, positive BCs were left unprocessed for 60–70% of the day due to restrictive opening hours. Treatment advice was given by 23% of CMLs (11/48) in ≥75% of the phone contacts. Rapid analyses (species identification and susceptibility testing with short incubation), performed on aliquots from positive cultures, were implemented in 18% of CMLs (9/49). Compared to 2013, species identification from subcultured colonies (<6 h) had become more common.ConclusionsCMLs have taken action to improve aspects of BC diagnostics, implementing satellite incubators, rapid species identification and susceptibility testing. However, the limited opening hours and availability of clinical microbiologists are confining the advantages of these changes.     

A review of dementia,focusing on the distinct roles of viral protein corona and MMP9 in dementia: Potential pharmacotherapeutic priorities

Dementia, in particular, is a defining feature of Alzheimer's and Parkinson's diseases. Because of the combination of motor and cognitive impairments, Parkinson's disease dementia (PDD) has a greater impact on affected people than Alzheimer's disease dementia (ADD) and others. If one family member develops dementia, the other members will suffer greatly in terms of social and occupational functioning. Currently, no relevant treatment is available based on an examination of the absolute pathophysiology of dementia. As a result, our objective of current review encouraged to look for dementia pharmacotherapy based on their pathogenesis. We systematically searched electronic databases such as PubMed, Scopus, and ESCI for information on the pathophysiology of demetia, as well as their treatment with allopathic and herbal medications. By modulating intermediate proteins, oxidative stress, viral protein corona, and MMP9 are etiological factors that cause dementia. The pathophysiology of ADD was described by two hypotheses: the amyloid cascade hypothesis and the tau and tangle hypothesis. ADD is caused by an increase in amyloid-beta (Aβ) and neurofibrillary tangles in the cerebrum. The viral protein corona (VPC) is more contagious and helps to form amyloid-beta (Aβ) plaques and neurofibrillary tangles in the cerebrum. Thioredoxin interacting protein (TXNIP) inside the BBB encourages Aβ to become more engaged. PDD is caused by decreased or absent dopamine secretion from nerve cells in the substantia nigra, as well as PRKN gene deletion/duplication mutations, and shift in the PRKN-PACRG organisation, all of which are linked to ageing. This article discussed the pathophysiology of dementia, as well as a list of herbal medications that can easily cross the BBB and have a therapeutic effect on dementia.     

Allergy diagnosis with the radioallergosorbent test: A comparison with the results of skin and provocation tests in an unselected group of children with asthma and hay fever

The radioallergosorbent test (RAST) has been used for in vitro diagnosis of asthma and hay fever in children as an integrated part of the routine procedure for allergy diagnosis. A positive RAST test was combined with a positive prick test in $\text{196}\text{235}$ (80 per cent) tests and with a positive provocation test in $\text{163}\text{182}$ (90 per cent) tests. When the provocation test was positive to dry pollen, the stock solution ($\text{1}\text{10}$ w./v. or 10,000 PNU) of the allergen extract RAST was quite often negative, a fact that explains the lower degree of correlation for a negative RAST test. A comparison between the prick test and the provocation test revealed a high proportion, $\text{54}\text{146}$ (37 per cent), of positive prick tests that could not be confirmed by the provocation test. RAST is a simple, reliable test for IgE antibodies that is very useful for in vitro diagnosis of atopic allergy on a routine basis. RAST is harmless and less traumatic than skin testing and therefore suitable for use even on very small children. The information obtained on the patient's hypersensitivity is more relevant than that from regular skin testing, probably comparable to skin test titration with selected allergens but not quite as good as provocation testing of the shock organ involved. Whenever a provocation test cannot be performed for each suspected allergen, an RAST test, possibly completed with a prick test, is recommended.     

Evaluation of multiplex Polymerase chain reaction utilising multiple targets in Mycobacterium tuberculosis direct test negative but culture positive cases: A potential method for enhancing the diagnosis of tuberculosis

Purpose: To evaluate multiplex Polymerase Chain Reaction (MPCR) utilising multiple targets (IS6110, Protein b [Pab] and MPB64 genes) in Mycobacterium tuberculosis Direct Test (MTD) negative but culture positive cases and comparison of MPCR with Real-Time polymerase chain reaction (RT-PCR) for diagnosis of tuberculosis. Materials and Methods: MPCR was carried out on 28 culture positive sputum samples. Out of 28 culture positive samples, 17 were originally reported, as MTD test negative and 11 were MTD test positive, respectively. The results of MPCR were compared with RT-PCR. To check the specificity of the tests, MPCR and RT-PCR were also evaluated with 16 non-tuberculous mycobacterial (NTM) isolates. Results: Out of 28 culture positive sputum samples, MPCR was positive in all 28/28 samples, whereas RT-PCR was positive in 27/28 samples and MTD test was originally tested positive in six sputum samples and on repeating MTD testing, five more sputum samples were positive and thus total number of MTD positive were 11/28 sputum samples, respectively. All the tests were negative on evaluation with all the 16 NTMs, thus giving specificity of 100% to all the tests; sensitivity of MPCR, RT-PCR and MTD tests were 100%, 96.42% and 39.28%, respectively, in these specifically selected samples. Conclusions: MPCR may be an important tool in the rapid diagnosis of tuberculosis especially in disease endemic, resource limited countries.