A Mycobacterium tuberculosis Beijing strain persists at high rates and extends its geographic boundaries 20 years after importation

Laura Pérez-Lago,María Isolina Campos-Herrero,Patricia Muñoz,Laura Sante,María Lecuona,Fernando Cañas,Berta Pino,Óscar Díez Gil,Rodolfo Copado,Carlos Martín,Sofía Samper,Darío García-De-Viedma

doi:10.1038/s41598-019-40525-6

Abstract

Transmission of Beijing Mycobacterium tuberculosis can be investigated based on genotypic analysis of clinical isolates. A Beijing strain began to spread on Gran Canaria Island, Spain, at the end of the last century. In 1996, only 3 years after its importation to the island, its frequency had increased to 27.1% of all the isolates. The strain was tracked during the following years, and the most recent data obtained corresponded to 2007-8, when its presence continued to be alarming (21%). In the current study, we updated data on the distribution of this strain 20 years (2013–2014) after it was first detected on the island and extended the analysis for the first time to all the mycobacteriology laboratories covering the population of the Canary Island archipelago. Rapid updating was enabled by means of 2 different strain-specific PCRs: one targeting a peculiar feature of the strain, which was identified based on an IS6110 copy mapping in the Rv2180c gene, and a newly defined strain-specific single nucleotide polymorphism, which was identified by whole-genome sequencing. The results showed that the strain has remained highly prevalent (20.90% of all isolates), has spread throughout the neighbouring islands, and has also reached high representativeness in them (11–32%).

Highlights

The Canary Islands are an archipelago located in the Atlantic Ocean, close to the North-West African coast
Material and Methods Study sample. 244 positive M. tuberculosis complex cultures (1 isolate per patient) from the 313 cases microbiologically confirmed in the 2013-4 period were available in the restrospective collection obtained from Hospital Universitario de Gran Canaria Dr Negrín, Hospital Universitario Insular de Gran Canaria (Gran Canaria island), Hospital José Molina Orosa (Lanzarote island), Hospital Universitario de Canarias and Hospital Na Sa de la Candelaria (Tenerife island)
Seventeen Beijing isolates were not detected by IS6110-PCR because they were included in the delivery with no results for this technique

Summary

Introduction

The Canary Islands are an archipelago located in the Atlantic Ocean, close to the North-West African coast. The archipelago comprises 7 main islands grouped into 2 provinces—Las Palmas (Gran Canaria, Lanzarote, and Fuerteventura islands) and Santa Cruz de Tenerife (Tenerife, La Palma, La Gomera, and El Hierro islands)— which constitute an autonomous community of Spain. More than 2 million inhabitants are distributed among the most populated islands (Tenerife, Gran Canaria, Lanzarote, and Fuerteventura). The latest official data, which are from 2016, show a decrease to 6.36/100 000 in Las Palmas, 4.28/100 000 in Santa Cruz de Tenerife, and 5.34/100 000 in the autonomous community as a whole. Due to its rapid spread and association with numerous outbreaks, the East Asian lineage of M. tuberculosis strains has caused global concern. The introduction of a Beijing strain on Gran Canaria Island and its fast spread in this community (27.1% of cases of tuberculosis) was detected in the 1990s. We applied a novel dual screening approach supported by 2 rapid methods based on strain-specific multiplex PCRs

Methods

Results

Conclusion