Mycobacterium caprae, a recently defined member of the Mycobacterium tuberculosis complex, causes tuberculosis among animals and, to a limited extent, in humans in several European countries. While in the ten year period until 2009, there was only one human tuberculosis case with Mycobacterium caprae documented in Austria (in 2008), in 2010 three such cases were registered for this mandatorily reportable disease. Already in fall 2008, the western provinces Tyrol and Vorarlberg had begun to test all cattle for tuberculosis, after documenting occurrence of Mycobacterium caprae in some herds of one of nine Tyrolean districts. More than 100 cows from 75 farms had to be culled. Cattle were supposed to have become infected after grazing on alpine pastures contaminated by diseased deer. In the affected district, the county of Reutte, neighbouring the province of Vorarlberg, more than 10% of the red deer (Cervus elaphus) population was found to be infected with Mycobacterium caprae. Overstocking and winter feeding (with "unnatural" crowding of deer at few feeding places) was considered the cause. In 2010, public authorities ordered decimation of half of approx. 1100 red deer in the affected county. The sudden emergence of three human Mycobacterium caprae infections in 2010 raised the question as to whether there was an epidemiological link between animal and human illness. Figure 2 depicts the geographic origin of the Mycobacterium caprae infections in cattle, deer (unpublished AGES data) and humans documented in 2010. MIRU genotyping was performed on these animal and human Mycobacterium caprae isolates. MIRU patterns from deer and cattle isolates were indistinguishable from each other, but clearly different from the three patterns of the human isolates. The molecular genetic analysis did not reflect patterns indicative of spread of Mycobacterium caprae from the veterinary outbreak in western Austria to the human cases in eastern Austria. MIRU-VNTR results were substantiated by epidemiological findings: patient A, a 13 year old girl of Turkish ancestry living in Vienna probably became infected when visiting her grandparents in rural Turkey during summer breaks. Patient B, a 85-year-old lady from Lower Austria, probably got infected by her late husband, who had the cattle of his farm culled due to bovine tuberculosis in the early 1960s. Patient C, a 70-year-old patient from Upper Austria probably got infected around 1965, when the cattle of his farm had to be culled by public order because of tuberculosis. Molecular typing was not only able to exclude a connection between the recent re-emergence of tuberculosis in cattle and deer with the occurrence of human Mycobacterium caprae cases but even to disprove the existence of a human outbreak.
Ten years ago, a single-endonuclease, amplified fragment length polymorphism analysis method by which the patterns are resolved by standard agarose electrophoresis, was adopted as an international standard by the European Working Group for Legionella Infections (EWGLI), especially for cases of travel-associated legionellosis. However, while this method allowed relatively reliable screening of isolates within a single laboratory, inter-laboratory comparison of the results still posed a significant hurdle. Therefore, EWGLI developed a sequence-based typing (SBT) scheme for clinical and environmental isolates of Legionella pneumophila, which is presently widely used in Europe in the investigation of outbreaks of legionellosis caused by Legionella pneumophila. The advantages of using a multilocus sequence typing approach with nonselective housekeeping genes has been well documented for various microorganisms. Using the so-called SBT protocol, the SBT database (provided by EWGLI in conjunction with the London based Health Protection Agency and the European Centre for Disease Prevention and Control in Stockholm under http://www.hpa-bioinformatics.org.uk/legionella/legionella_sbt/php/sbt_homepage.php) allows assignment of the seven ordered alleles, flaA, pilE, asd, mip, mompS, proA, and neuA as described by Gaia et al. and Ratzow et al., and representation as one of presently 1032 sequence types (ST). ST 81 for instance has the allelic profile, i.e. the ordered string of allele numbers separated by commas, 2,10,3,28,9,4,9.