Clinical Microbiological Diagnostics 2.0

Life has changed since the Dutch botanist Anthonie van Leeuwenhoek (1632-1723) revealed the diversity and ubiquity of the microbial world through the discovery of microscopy. Van Leeuwenhoek can be considered to be the fi rst genuine microbiologist. Microscopic evidence provided support for the emerging germ theory of disease in the 19th century. In the 1880s, Robert Koch defi ned his postulates for determining whether or not a microorganism is the etiological agens of a disease. Since the 19th century, advances in knowledge have included the discovery of viruses, chlamydiae, mycoplasmata and rickettsiae as new classes of microorganisms that cannot (yet) be grown in pure culture, but require living cells for reproduction. The spectrum of bacterial, fungal and protozoan pathogens has been expanding with improved culture techniques and the development of advanced imaging techniques. However, the most revolutionary advance in biomedical science since Van Leeuwenhoek, is due to the discovery of nucleic acids in 1871 by Miescher, which lead to the discovery of DNA as the source of genetic information and as the basis for characterization of an organism in 1953 by Watson, Crick and Wilkin

Costly apology and self-punishment after an unintentional transgression

Background: Infections with multidrug-resistant (MDR) microorganisms are an increasing threat to hospitalized patients. Although rapid typing of MDR microorganisms is required to apply targeted prevention measures, technical barriers often prevent this. We aimed to assess whether extended-spectrum beta-lactamase (ESBL)-producing Klebsiella species are transmitted between patients and whether routine, rapid typing is needed. Methods: For 43 months, the clonality of all ESBL-producing Klebsiella isolates from patients admitted to Erasmus MC University Medical Center in Rotterdam, the Netherlands was assessed with Raman spectroscopy. A cluster was defined as n ≥2 patients who had identical isolates. Primary patients were the first patients in each cluster. Secondary patients were those identified with an isolate clonally related to the isolate of the primary patient. Results: Isolates from 132 patients were analyzed. We identified 17 clusters, with 17 primary and 56 secondary patients. Fifty-nine patients had a unique isolate. Patients (n = 15) in four out of the 17 clusters were epidemiologically related. Ten of these 15 patients developed an infection. Conclusions: Clonal outbreaks of ESBL-producing Klebsiella species were detected in our hospital. Theoretically, after Raman spectroscopy had detected a cluster of n ≥2, six infections in secondary patients could have been prevented. These findings demonstrate that spread of ESBLproducing Klebsiella species occurs, even in a non-outbreak setting, and underscore the need for routine rapid typing of these MDR bacteria

Comparison of the COBAS AMPLICOR MTB and BDProbeTec ET assays for detection of Mycobacterium tuberculosis in respiratory specimens.

The performances of the BDProbeTec ET (Becton Dickinson) and COBAS AMPLICOR MTB (Roche) were retrospectively evaluated for detecting Mycobacterium tuberculosis complex in various respiratory specimens. The BACTEC and MGIT liquid culture system (Becton Dickinson) was used as a reference method. A total of 824 respiratory specimens, comprised of sputa, bronchoalveolar lavage fluid, and bronchial and tracheal aspirates from 580 patients, were evaluated. Out of 824 clinical specimens, 109 specimens from 43 patients were culture positive for M. tuberculosis. Of these 109 specimens, 67 were smear positive, 85 were positive by the COBAS AMPLICOR MTB test, and 94 were positive by the BDProbeTec ET. Of the 715 culture-negative specimens, 17 were positive by the auramine staining, 11 were positive by the COBAS AMPLICOR MTB test, and 12 were positive by the BDProbeTec ET. After discrepancy analysis and review of the patients' clinical data, 130 specimens from 50 patients were considered "true-positive" specimens. This resulted in the following sensitivities: microscopy, 61.5%; COBAS AMPLICOR MTB test, 78.0%; and BDProbeTec ET, 86.2%. The specificities of each system, based on the clinical diagnosis, were 99.7% for microscopy, 99.9% for the COBAS AMPLICOR MTB test, and 99.9% for the BDProbeTec ET. The data presented represent a considerable number of specimens evaluated with a considerable number of culture- and auramine-positive and culture-positive and auramine-negative results and therefore give a realistic view of how the data should be interpreted in a daily routine situation. Specifically, the data with regard to the culture-positive and auramine-negative specimens are useful, because in a routine situation, auramine-negative specimens are sometimes accepted, on clinical indications, to be analyzed by an amplification method

Clinical characteristics of patients infected or colonized with ESBL-producing <i>Klebsiella</i> spp. and clinical characteristics of primary and secondary patients.

<p>Abbreviations: COPD, chronic obstructive pulmonary disease, SD, standard deviation, no., number, n.a., not applicable.</p><p>^aDeath from any cause within one year after the first positive culture;</p><p>^bIncluding patients with a unique isolate</p><p>Clinical characteristics of patients infected or colonized with ESBL-producing <i>Klebsiella</i> spp. and clinical characteristics of primary and secondary patients.</p

The number of infected and colonized patients in the eight clusters identified with Raman spectroscopy with a definite or probable epidemiological relationship.

<p>Abbreviations: no., number; prim, primary patients including patients with a unique isolate; sec, secondary patients. Epidemiological relatedness is presented as number of patients.</p><p>The number of infected and colonized patients in the eight clusters identified with Raman spectroscopy with a definite or probable epidemiological relationship.</p

Distribution of patients identified with an ESBL-producing <i>Klebsiella</i> spp. (<i>n</i> = 132), January 2010 until August 2013.

<p>Black = primary patients (<i>n</i> = 17); the first patient in time in a cluster, identified with Raman spectroscopy. Grey = secondary patients (<i>n</i> = 56); all subsequent patients who had a proven clonal relationship with the primary patient. Light grey = patients with a unique isolate (<i>n</i> = 59).</p