Investigating the Origin of Mycobacterium chimaera Contamination in Heater-Cooler Units: Integrated Analysis with Fourier Transform Infrared Spectroscopy and Whole-Genome Sequencing.

Mycobacterium chimaera is ubiquitously spread in the environment, including factory and hospital water systems. Invasive cases of M. chimaera infection have been associated with aerosols produced by the use of heater-cooler units (HCU) during cardiac surgery. The aim of this study was to evaluate for the first time the performance of IR-Biotyper system on a large number of M. chimaera isolates collected from longitudinal environmental HCUs samples and water sources from hospitals located in three Italian provinces. In addition, IR-Biotyper results were compared with whole-genome sequencing (WGS) analysis, the reference method for molecular epidemiology, to investigate the origin of M. chimaera contamination of HCUs. From November 2018 to May 2021, 417 water samples from 52 HCUs (Stockert 3T, n = 41 and HCU40, n = 11) and 23 hospital taps (used to fill the HCU tanks) were concentrated, decontaminated, and cultured for M. chimaera. Positive cultures (n = 53) were purified by agar plate subcultures and analyzed by IR-Biotyper platform and Ion Torrent sequencing system. IR-Biotyper spectra results were analyzed using a statistical approach of dimensionality reduction by linear discriminant analysis (LDA), generating three separate clusters of M. chimaera, ascribable to each hospital. Furthermore, the only M. chimaera-positive sample from tap water clustered with the isolates from the HCUs of the same hospital, confirming that the plumbing system could represent the source of HCU contamination and, potentially, of patient infection. According to the genome-based phylogenies and following the classification proposed by van Ingen and collaborators in 2017, three distinct M. chimaera groups appear to have contaminated the HCU water systems: subgroups 1.1, 2.1, and branch 2. Most of the strains isolated from HCUs at the same hospital share a highly similar genetic profile. The nonrandom distribution obtained with WGS and IR-Biotyper leads to the hypothesis that M. chimaera subtypes circulating in the local plumbing colonize HCUs through the absolute filter, in addition with the current hypothesis that contamination occurs at the HCU production site. This opens the possibility that other medical equipment, such as endoscope reprocessing device or hemodialysis systems, could be contaminated by M. chimaera. IMPORTANCE Our manuscript focuses on interventions to reduce waterborne disease transmission, improve sanitation, and control infection. Sanitary water can be contaminated by nontuberculous Mycobacteria, including M. chimaera, a causative agent of invasive infections in immunocompromised patients. We found highly similar genetic and phenotypic profiles of M. chimaera isolated from heater-cooler units (HCU) used during surgery to thermo-regulate patients' body temperature, and from the same hospital tap water. These results lead to the hypothesis that M. chimaera subtypes circulating in the local plumbing colonize HCUs through the absolute filter, adding to the current hypothesis that contamination occurs at the HCU production site. In addition, this opens the possibility that other medical equipment using sanitized water, such as endoscope reprocessing devices or hemodialysis systems, could be contaminated by nontuberculous Mycobacteria, suggesting the need for environmental surveillance and associated control measures.

Multidrug-Resistant Tuberculosis In A Referral Center In Rome: 2011- 2016.

PURPOSE: Multidrug-resistant tuberculosis (MDR-TB) is a major burden to public health in low incidence countries in Europe. The aim of this study was to attempt to have a better insight into the trends of MDR-TB in the metropolitan area of Rome, within the Italian and the foreign-born population, based on microbiological and demographic data. PATIENTS AND METHODS: We performed a prospective study, collecting microbiological data based on phenotypic drug-resistant testing (DST) of TB strains consecutively isolated in a referral hospital in Rome, the capital city of a low TB incidence country, over a 6-year period, and correlated them to the geographical origin of patients. This study was carried out in a referral hospital for patients with drug-resistant TB from the whole region. RESULTS: Drug-resistance data from 926 patients with a microbiological diagnosis of TB from 2011 to 2016 show a 5.5% rate of MDR-TB, mostly occurring in patients born in a single East European country, that has a high incidence of MDR-TB. The strains isolated from these patients frequently carry additional resistances, leading to an increased risk of developing extensively drug-resistant (XDR) TB. CONCLUSION: In the great metropolitan area of Rome, MDR-TB more frequently occurs in patients who were born in a single country from Eastern Europe known to have high rates of MDR-TB and long-time residents in Italy. Recent immigrants from non-European countries do not appear to contribute to the rates of MDR-TB reported in this article. This knowledge of local TB trends could help improve the measures of surveillance and prevention of disease.

Clinical evaluation of TRCReady M.TB for rapid automated detection of M. tuberculosis complex in respiratory samples.

SETTING: Timely diagnosis of tuberculosis (TB) is essential for effectively controlling and managing the disease. Although international guidelines recommend acid-fast bacilli staining and culture as the 'gold standard', new molecular methods are available to safely and rapidly identify positive samples. OBJECTIVE: To evaluate the performance of the newer and fully automated version of a molecular assay for rRNA amplification (TRCReady® M.TB) on 1028 respiratory samples collected from 378 patients for its possible use as a reliable screening method. Results were evaluated using culture as the reference test. RESULTS: Of four diagnostic protocols employed, best results were obtained when TRCReady M.TB was used together with microscopy on the first respiratory sample, followed by microscopy alone on a second one. The sensitivity and specificity were respectively 97% and 100%, with a turnaround time of 24 h. We propose a possible laboratory algorithm for rapid identification of patients with TB. CONCLUSIONS: TRCReady offers the advantages of full automation and avoidance of cross-contamination. As such, it should be considered as a more economical option for TB screening than other commercial assays that are currently available.

Evaluation of a rapid and sensitive RT-qPCR assay for the detection of Ebola Virus.

BACKGROUND: The 2013-2016 Ebola virus disease (EVD) outbreak showed a lack of diagnostic point-of-care methods. Currently, EBOV diagnosis relies on quantitative reverse-transcription-PCR (RT- qPCR), highly specific and sensitive, but requiring skilled personnel and well-equipped laboratories. In field settings, these factors and others, such as samples' time of collection and transportation, determine a prolonged turnaround-time to final results. In outbreak scenarios, a rapid and transportable method could eliminate issues of cohorting suspected and actual EVD patients for lack of diagnostic certainty. The aim of this study was the field evaluation of the new fast, easy-to-use and reliable RT-qPCR assay and platform for EBOV detection, developed in the framework of the EbolaMoDRAD project by CLONIT S.r.l. and STMicroelectronics S.r.l. STUDY DESIGN: We evaluated its performance during the outbreak and in further studies in the EVD laboratory at the Princess Christian Maternity Hospital (PCMH) in Freetown (Sierra Leone) run by Emergency NGO and the Italian National Institute for Infectious Diseases (INMI). The assay was tested on residual aliquots of clinical specimens from EBOV-positive or -negative patients (n=116, EVD prevalence 37%). RESULTS AND CONCLUSION: Overall, the test was very easy-to-use and the instrument was robust and reliable in field-settings. The sensitivity of the assay was 100% and the specificity was 98.63% (95%CI: 96.34-100.92%). The positive and negative predictive values were 97.73 (95%CI:94.77-100.68%) and 100%, respectively. The high sensitivity and specificity of this new assay indicate that it is promising for laboratory diagnosis, especially in resource-limited settings.

Exploring MALDI-TOF MS approach for a rapid identification of Mycobacterium avium ssp. paratuberculosis field isolates.

AIMS: The aim of the study was to explore the suitability of matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) for a rapid and correct identification of Mycobacterium avium ssp. paratuberculosis (MAP) field isolates. METHODS AND RESULTS: MALDI-TOF MS approach is becoming one of the most popular tests for the identification of intact bacterial cells which has been shown to be fast and reliable. For this purpose, 36 MAP field isolates were analysed through MALDI-TOF MS and the spectra compared with two different databases: one provided by the vendor of the system employed (Biotyper ver. 3·0; Bruker Daltonics) and a homemade database containing spectra from both tuberculous and nontuberculous Mycobacteria. Moreover, principal component analysis procedure was employed to confirm the ability of MALDI-TOF MS to discriminate between very closely related subspecies. Our results suggest MAP can be differentiated from other Mycobacterium species, both when the species are very close (M. intracellulare) and when belonging to different subspecies (M. avium ssp. avium and M. avium ssp. silvaticum). CONCLUSIONS: The procedure applied is fast, easy to perform, and achieves an earlier accurate species identification of MAP and nontuberculous Mycobacteria in comparison to other procedures. SIGNIFICANCE AND IMPACT OF THE STUDY: The gold standard test for the diagnosis of paratuberculosis is still isolation of MAP by cultural methods, but additional assays, such as qPCR and subculturing for determination of mycobactin dependency are required to confirm its identification. We have provided here evidence pertaining to the usefulness of MALDI-TOF MS approach for a rapid identification of this mycobacterium among other members of M. avium complex.