Comparison of the sodium hydroxide specimen processing method with the C18-carboxypropylbetaine specimen processing method using independent specimens with auramine smear, the MB/BacT liquid culture system, and the COBAS AMPLICOR MTB test

Chinese Expert Consensus on the Nucleic Acid Detection of SARS-CoV-2

The coronavirus disease 2019 (COVID-19) has already become a pandemic wherein the infection's timely diagnosis has proven beneficial to patient treatment and disease control. Nucleic acid detection has been the primary laboratory diagnostic method for the detection of SARS-CoV-2. To ensure laboratory staff safety and quality nucleic acid testing, the Chinese Society of Laboratory Medicine formulated this consensus, based on the Chinese National Recommendations and previous literature for nucleic acid detection. A working group comprises 34 hospital professionals experience with real-time polymerase chain reactions (PCR) testing for SARS-CoV-2 drafted guidance statements during online discussions. A modified Delphi methodology was used in forming a consensus among a wider group of hospital professionals with SARS-CoV-2 detection experience. Guidance statements were developed for four categories: (I) specimen type, priority, collecting, transportation and receiving; (II) nucleic acid isolation and amplification; (III) quality control; (IV) biosafety management and decontamination. The modified Delphi voting process included a total of 29 guidance statements and final agreement. Consensus was reached after two rounds of voting. Recommendations were established for the detection of SARS-CoV-2 using real time PCR testing based on evidence and group consensus. The manuscript was evaluated against The Appraisal of Guidelines for Research & Evaluation Instrument (AGREE II) and was developed to aid medical laboratory staff in the detection of the ribonucleic acid (RNA) of SARS-CoV-2.

Is real-time PCR better than conventional PCR for Mycobacterium tuberculosis complex detection in clinical samples?

Cobas Amplicor MTB and later Cobas TaqMan MTB were used to test a very large series of consecutive specimens received for tuberculosis diagnosis. Performance parameters were estimated and compared overall and for separate specimen categories. Both systems showed excellent specificity, and that of TaqMan was the higher. The sensitivities were similar but satisfactory only with respiratory specimens and smear-positive samples.

Laboratory diagnosis of tuberculosis in resource-poor countries: challenges and opportunities

With an estimated 9.4 million new cases globally, tuberculosis (TB) continues to be a major public health concern. Eighty percent of all cases worldwide occur in 22 high-burden, mainly resource-poor settings. This devastating impact of tuberculosis on vulnerable populations is also driven by its deadly synergy with HIV. Therefore, building capacity and enhancing universal access to rapid and accurate laboratory diagnostics are necessary to control TB and HIV-TB coinfections in resource-limited countries. The present review describes several new and established methods as well as the issues and challenges associated with implementing quality tuberculosis laboratory services in such countries. Recently, the WHO has endorsed some of these novel methods, and they have been made available at discounted prices for procurement by the public health sector of high-burden countries. In addition, international and national laboratory partners and donors are currently evaluating other new diagnostics that will allow further and more rapid testing in point-of-care settings. While some techniques are simple, others have complex requirements, and therefore, it is important to carefully determine how to link these new tests and incorporate them within a country's national diagnostic algorithm. Finally, the successful implementation of these methods is dependent on key partnerships in the international laboratory community and ensuring that adequate quality assurance programs are inherent in each country's laboratory network.

[Utility of molecular biology in the microbiological diagnosis of mycobacterial infections]

Species within the Mycobacterium genus are of major medical interest, since, together with environmental and opportunistic species, there are two species (Mycobacterium tuberculosis and Mycobacterium leprae) that remain an important public health challenge. Despite efforts to control tuberculosis (TB), this disease remains one of the most prominent health problems worldwide. In the last few years, mycobacteriology has experienced major technological advances. Nevertheless, the early diagnosis of mycobacterial infection and, especially of TB, is still based on microscopic examination of properly stained samples. At present, this procedure is still the simplest, fastest and most cost-effective method for preliminary diagnostic guidance. Effective control of TB is based on rapid detection of M. tuberculosis, followed by immediate implementation of the appropriate antituberculosis therapy. Because of the emergence of multidrug resistant strains, the development of rapid diagnostic methods, both for identification of M. tuberculosis and susceptibility testing, has become a pressing need. The availability of molecular epidemiology methods that are easy to implement and standardized and that would allow identification of related cases is of key importance to identify epidemic outbreaks and control the spread of TB. Despite the evident progress in the molecular diagnosis of mycobacterial infections, the available techniques are still inadequate. In this review, we describe the state of the art of the main molecular techniques for direct detection of mycobacteria in clinical samples, their identification, detection of resistance to the most important antituberculosis agents, and molecular epidemiology. In each case, we describe the advantages and limitations of current techniques. In the near future, clinical mycobacteriology will probably evolve to the universal use of genetic techniques for direct diagnosis and detection of resistance. The molecular epidemiology of TB will be performed, in its various applications, by faster and more automated techniques than those currently available.

Microbiological diagnostic procedures in respiratory infections: mycobacterial infections

This article will review traditional and newer microbiological techniques for the diagnosis of mycobacterial respiratory infections. It will concentrate on the diagnosis of infections due to Mycobacterium tuberculosis, the main mycobacterium causing respiratory infections of clinical and public health importance. The diagnosis of respiratory disease associated with non-tuberculous mycobacteria (NTM), particularly in children with underlying airway pathology such as cystic fibrosis (CF) or bronchiectasis, will be briefly discussed. With respect to the diagnosis of tuberculosis (TB), the review will concentrate on the diagnosis of patients with symptoms and/or signs of clinical disease, rather than the detection of exposure or asymptomatic infection. It will not specifically address the assessment of pre-test probability based on clinical or epidemiological factors, the use of radiological investigations or the investigation of extrathoracic lymph node disease or chest wall disease. The role of newer diagnostic modalities including nucleic acid detection (NAD) and gamma-interferon assays in paediatric practice will be reviewed, and suggestions made as to how they may fit into contemporary diagnostic algorithms.