scholarly journals Alternative Growth Behavior ofMycobacterium AviumSubspecies and Staphylococci with Implications for Clinical Microbiology and Blood Culture

2016 ◽  
Author(s):  
Peilin Zhang ◽  
Lawrence M. Minardi ◽  
J. Todd Kuenstner ◽  
Steve M. Zekan

AbstractRapid culture ofMycobacteriumavium subspecies paratuberculosis (MAP) from patients remains a challenge. During the process of developing a rapid culture method for MAP, we found that there is an alternative growth behavior present in MAP, MAH (Mycobacterium aviumsubspecies hominissuis) and other bacteria such asStaphylococcus aureus, andStaphylococcus pseudintermedius. The bacterial DNA, RNA and proteins are present in the supernatants of the liquid culture media after routine microcentrifugation. When cultured in the solid media plate, there are a limited number of colonies developed for MAP and MAH disproportionate to the growth. We believe there is an alternative growth behavior for MAP, MAH and other bacteria similar to “phenoptosis”. Based on the alternative bacterial growth behavior, we tested 62 blood culture specimens that have been reported negative by routine automated blood culture method after 5 days of incubation. We used alternative culture media and molecular diagnostic techniques to test these negative culture bottles, and we found a large percentage of bacterial growth by alternative culture media (32%) and by molecular PCR amplification using 16s rDNA primer set and DNA sequencing (69%). The sensitivity of detection by the molecular PCR/sequencing method is significantly higher than by routine automated blood culture. Given the challenge of early diagnosis of sepsis in the hospital setting, it is necessary to develop more sensitive and faster diagnostic tools to guide clinical practice and improve the outcome of sepsis management.

Author(s):  
Antonio Lopez-Beltran ◽  
Rodolfo Montironi ◽  
Liang Cheng

In the past 50 years, classification systems for renal neoplasms have become increasingly complex as distinctive morphologic patterns in renal neoplasms have been recognized and correlated with clinical findings. In addition to classic histopatology, more sophisticated diagnostic tools, including electron microscopy, immunohistochemistry, cytogenetics, and molecular diagnostic techniques have greatly influenced distinctions between various types of renal neoplasms. The current World Health Organization classification of renal neoplasms encompasses nearly 50 distinctive renal neoplasms categorized as malignant or benign tumours. These categories have been expanded during recent years to incorporate newer histotypes, thus suggesting that the next revision of this classification will incorporate some recently recognized entities. In this chapter, we examine clinicopathologic and genetic features of the renal tumours most often seen in clinical practice.


Author(s):  
Carmen Alicia Garcia-Gutiérrez ◽  
María Soledad Cuétara-García ◽  
María Dolores Moragues ◽  
Jorge Ligero ◽  
Sara María Quevedo ◽  
...  

Abstract Background Although most bloodstream yeast infections are caused by Candida spp., infections by rare or less common species have increased in recent years. Diagnosis of infections caused by these species is difficult due to the lack of specific symptoms and adequate diagnostic tools. Cases presentation We describe two cases of fungemia by Rhodotorula mucilaginosa within a few months of each other, in a secondary Spanish hospital. In both cases, diagnosis was challenging. Blood subcultures in conventional fungal media were persistently negatives and the use of non-conventional fungal media was essential for isolating the yeasts and achieving a correct diagnosis. 1–3 beta-d-glucan detection and a panfungal PCR assay were helpful techniques to confirm the diagnosis Conclusion It is highly important to establish an early diagnosis for fungemia. The process is challenging because often non-specific symptoms are presents. When yeasts grow in blood cultures other genera than Candida spp. could be the cause of infection. Patient risk factors should be assessed to incorporate alternative culture media and the available rapid diagnostic test, in order to provide an early recognition of the pathogen.


Diagnostics ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 78 ◽  
Author(s):  
Anthony Harries ◽  
Ajay Kumar

Case finding and the diagnosis of tuberculosis (TB) are key activities to reach the World Health Organization’s End TB targets by 2030. This paper focuses on the diagnosis of pulmonary TB (PTB) in low- and middle-income countries. Sputum smear microscopy, despite its many limitations, remains the primary diagnostic tool in peripheral health facilities; however, this is being replaced by molecular diagnostic techniques, particularly Xpert MTB/RIF, which allows a bacteriologically confirmed diagnosis of TB along with information about whether or not the organism is resistant to rifampicin within two hours. Other useful diagnostic tools at peripheral facilities include chest radiography, urine lipoarabinomannan (TB-LAM) in HIV-infected patients with advanced immunodeficiency, and the loop-mediated isothermal amplification (TB-LAMP) test which may be superior to smear microscopy. National Reference Laboratories work at a higher level, largely performing culture and phenotypic drug susceptibility testing which is complemented by genotypic methods such as line probe assays for detecting resistance to isoniazid, rifampicin, and second-line drugs. Tuberculin skin testing, interferon gamma release assays, and commercial serological tests are not recommended for the diagnosis of active TB. Linking diagnosis to treatment and care is often poor, and this aspect of TB management needs far more attention than it currently receives.


2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S302-S302
Author(s):  
Jeremy Green ◽  
Caitlin Carter ◽  
Craig Chandler ◽  
Angela Clark ◽  
Stephanie Thatcher

Abstract Background Timely bloodstream infection (BSI) pathogen identification requires robust sample purification and testing methods that can accommodate the wide variety of blood culture media used for growing positive blood culture (PBC) specimens. Sensitive molecular methods are needed for identification of all organisms present in PBD, especially polymicrobial cultures which can be difficult to identify with standard methods. Multiple types of BD and BioMérieux blood culture media commonly used in hospital laboratories were used to evaluate the performance of a prototype BioFire® FilmArray® Blood Culture Identification 2 (BCID2) Panel with PBCs. Methods Fungi (seven) and bacteria (19) were independently seeded in blood samples, inoculated into as many as eight different types of blood culture bottles, and incubated on the recommended instrument. Time to positivity (TTP) was recorded for all PBCs. Subsets of PBCs were enumerated and tested on the BioFire BCID2 Panel and BioFire® FilmArray® Blood Culture Identification (BCID) panel. Polymicrobial testing was performed by seeding fast and slow growing organisms into the same bottles. Results Over 750 PBCs were enumerated; ~500 PBCs were tested on the BioFire BCID2, and over 200 were also tested on the BioFire BCID. 100% of seeded PBCs tested on the BioFire Panels resulted in correct pathogen identification. Across all bottle types, fungi grew to levels ranging from 8E+05 to 5E+07 CFU/mL, Gram-positive bacteria titers ranged from 7E+06 to 2E+09, and Gram-negative bacteria titers ranged from 9E+07 to 3E+09. Polymicrobial PBCs (30) had reduced titers of slow growing organisms when seeded with fast growing organisms but were detected by both BioFire BCID Panels at a rate of 99%. Conclusion This study demonstrates that a prototype BioFire BCID2 Panel, and the BioFire BCID Panel, robustly detect and identify (100%) BSI pathogens over a multitude of common blood culture media and systems. Results confirm PBC (single and polymicrobial) titers are above the levels of sensitivity for both BioFire panels. An expanded menu of targets (organism and resistance) and faster run time with the BioFire BCID2 Panel will offer a flexible and comprehensive aid in the diagnosis of BSIs. The BioFire® BCID2 Panel has not yet been evaluated by the FDA or other regulatory agencies for in vitro diagnostic use. Disclosures J. Green, BioFire Diagnostics, LLC: Employee, Salary. C. Carter, BioFire Diagnostics, LLC: Employee, Salary. C. Chandler, BioFire Diagnostics, LLC: Employee, Salary. A. Clark, BioFire Diagnostics, LLC: Employee, Salary. S. Thatcher, BioFire Diagnostics, LLC: Employee, Salary.


2018 ◽  
Vol 31 (2) ◽  
Author(s):  
Mridu Sinha ◽  
Julietta Jupe ◽  
Hannah Mack ◽  
Todd P. Coleman ◽  
Shelley M. Lawrence ◽  
...  

SUMMARYRapid and accurate profiling of infection-causing pathogens remains a significant challenge in modern health care. Despite advances in molecular diagnostic techniques, blood culture analysis remains the gold standard for diagnosing sepsis. However, this method is too slow and cumbersome to significantly influence the initial management of patients. The swift initiation of precise and targeted antibiotic therapies depends on the ability of a sepsis diagnostic test to capture clinically relevant organisms along with antimicrobial resistance within 1 to 3 h. The administration of appropriate, narrow-spectrum antibiotics demands that such a test be extremely sensitive with a high negative predictive value. In addition, it should utilize small sample volumes and detect polymicrobial infections and contaminants. All of this must be accomplished with a platform that is easily integrated into the clinical workflow. In this review, we outline the limitations of routine blood culture testing and discuss how emerging sepsis technologies are converging on the characteristics of the ideal sepsis diagnostic test. We include seven molecular technologies that have been validated on clinical blood specimens or mock samples using human blood. In addition, we discuss advances in machine learning technologies that use electronic medical record data to provide contextual evaluation support for clinical decision-making.


Animals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 20
Author(s):  
Luigi De Grossi ◽  
Davide Santori ◽  
Antonino Barone ◽  
Silvia Abbruzzese ◽  
Matteo Ricchi ◽  
...  

Paratuberculosis is a chronic disease of ruminants caused by Mycobacterium avium subsp. Paratuberculosis (MAP). Since isolation of MAP type I (S) is rarely reported in Italy, our research was aimed at isolating, by an inexpensive liquid culture manual method, this type of MAP isolates. At first, we used an ELISA to point out to serologically positive samples from five flocks. Secondly, we used a fecal direct IS900-qPCR on the ELISA positive samples, in order to detect shedder animals. Feces from IS900-qPCR positive samples were inoculated in solid and liquid culture media. IS900-qPCR was further used to test the growth of MAP isolates in liquid medium, which were further confirmed by f57-qPCR and submitted to typing by specific PCR in order to identify the MAP type. Twenty-eight samples (24 fecal and four tissutal samples) were processed by culture methods, resulting in the isolation of six type I MAP field isolates. Notably, no isolates were recovered by solid media, underlining the utility of this liquid method. Few data about this type of MAP are currently available in Italy, and further analyses should be carried out in order to study the origin and epidemiology of type I strains circulating in Italy.


3 Biotech ◽  
2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Domenico Rizzo ◽  
Nicola Luchi ◽  
Daniele Da Lio ◽  
Linda Bartolini ◽  
Francesco Nugnes ◽  
...  

AbstractThe red-necked longhorn beetle Aromia bungii (Faldermann, 1835) (Coleoptera: Cerambycidae) is native to east Asia, where it is a major pest of cultivated and ornamental species of the genus Prunus. Morphological or molecular discrimination of adults or larval specimens is required to identify this invasive wood borer. However, recovering larval stages of the pest from trunks and branches causes extensive damage to plants and is timewasting. An alternative approach consists in applying non-invasive molecular diagnostic tools to biological traces (i.e., fecal pellets, frass). In this way, infestations in host plants can be detected without destructive methods. This paper presents a protocol based on both real-time and visual loop-mediated isothermal amplification (LAMP), using DNA of A. bungii extracted from fecal particles in larval frass. Laboratory validations demonstrated the robustness of the protocols adopted and their reliability was confirmed performing an inter-lab blind panel. The LAMP assay and the qPCR SYBR Green method using the F3/B3 LAMP external primers were equally sensitive, and both were more sensitive than the conventional PCR (sensitivity > 103 to the same starting matrix). The visual LAMP protocol, due to the relatively easy performance of the method, could be a useful tool to apply in rapid monitoring of A. bungii and in the management of its outbreaks.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
James M. Hodge ◽  
Andrey A. Yurchenko ◽  
Dmitriy A. Karagodin ◽  
Reem A. Masri ◽  
Ryan C. Smith ◽  
...  

Abstract Background The malaria mosquito Anopheles punctipennis, a widely distributed species in North America, is capable of transmitting human malaria and is actively involved in the transmission of the ungulate malaria parasite Plasmodium odocoilei. However, molecular diagnostic tools based on Internal Transcribed Spacer 2 (ITS2) of ribosomal DNA are lacking for this species. Anopheles punctipennis is a former member of the Anopheles maculipennis complex but its systematic position remains unclear. Methods In this study, ITS2 sequences were obtained from 276 An. punctipennis specimens collected in the eastern and midwestern United States and a simple and robust Restriction Fragment Length Polymorphism approach for species identification was developed. The maximum-likelihood phylogenetic tree was constructed based on ITS2 sequences available through this study and from GenBank for 20 species of Anopheles. Results The analysis demonstrated a consistent ITS2 sequence length and showed no indications of intragenomic variation among the samples based on ITS2, suggesting that An. punctipennis represents a single species in the studied geographic locations. In this study, An. punctipennis was found in urban, rural, and forest settings, suggesting its potential broad role in pathogen transmission. Phylogeny based on ITS2 sequence comparison demonstrated the close relationship of this species with other members of the Maculipennis group. Conclusions This study developed molecular tools based on ITS2 sequences for the malaria vector An. punctipennis and clarified the phylogenetic position of the species within the Maculipennis group.


2002 ◽  
Vol 15 (1) ◽  
pp. 125-144 ◽  
Author(s):  
Cees M. Verduin ◽  
Cees Hol ◽  
André Fleer ◽  
Hans van Dijk ◽  
Alex van Belkum

SUMMARY Moraxella catarrhalis (formerly known as Branhamella catarrhalis) has emerged as a significant bacterial pathogen of humans over the past two decades. During this period, microbiological and molecular diagnostic techniques have been developed and improved for M. catarrhalis, allowing the adequate determination and taxonomic positioning of this pathogen. Over the same period, studies have revealed its involvement in respiratory (e.g., sinusitis, otitis media, bronchitis, and pneumonia) and ocular infections in children and in laryngitis, bronchitis, and pneumonia in adults. The development of (molecular) epidemiological tools has enabled the national and international distribution of M. catarrhalis strains to be established, and has allowed the monitoring of nosocomial infections and the dynamics of carriage. Indeed, such monitoring has revealed an increasing number of Β-lactamase-positive M. catarrhalis isolates (now well above 90%), underscoring the pathogenic potential of this organism. Although a number of putative M. catarrhalis virulence factors have been identified and described in detail, their relationship to actual bacterial adhesion, invasion, complement resistance, etc. (and ultimately their role in infection and immunity), has been established in a only few cases. In the past 10 years, various animal models for the study of M. catarrhalis pathogenicity have been described, although not all of these models are equally suitable for the study of human infection. Techniques involving the molecular manipulation of M. catarrhalis genes and antigens are also advancing our knowledge of the host response to and pathogenesis of this bacterial species in humans, as well as providing insights into possible vaccine candidates. This review aims to outline our current knowledge of M. catarrhalis, an organism that has evolved from an emerging to a well-established human pathogen.


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