A Brief Update on Mycobacterial Taxonomy, 2020 to 2022.

This brief update provides details regarding two newly described species in the genus Mycobacterium that were identified from humans or associated with human disease and have been validly published for the period January 2020 through October 2022.

SARS-CoV-2 Supply Shortages and Tuberculosis Diagnostics: Current Issues Requiring Immediate Solutions.

The SARS-CoV-2 pandemic has strained manufacturing capacity worldwide, resulting in significant shortages of laboratory supplies both directly and indirectly. Such shortages include probe-based kits for detection of the Mycobacterium tuberculosis complex from positive liquid broth cultures. These shortages and possible loss of this particular assay have consequences for laboratory testing algorithms and public health in the United States. As there are no FDA-approved, commercially available options that currently exist which could immediately fill this gap, laboratories must identify alternatives and plan for modifying current testing algorithms to accommodate this change.

Dynamic relocalization of cytosolic type III secretion system components prevents premature protein secretion at low external pH.

Many bacterial pathogens use a type III secretion system (T3SS) to manipulate host cells. Protein secretion by the T3SS injectisome is activated upon contact to any host cell, and it has been unclear how premature secretion is prevented during infection. Here we report that in the gastrointestinal pathogens Yersinia enterocolitica and Shigella flexneri, cytosolic injectisome components are temporarily released from the proximal interface of the injectisome at low external pH, preventing protein secretion in acidic environments, such as the stomach. We show that in Yersinia enterocolitica, low external pH is detected in the periplasm and leads to a partial dissociation of the inner membrane injectisome component SctD, which in turn causes the dissociation of the cytosolic T3SS components. This effect is reversed upon restoration of neutral pH, allowing a fast activation of the T3SS at the native target regions within the host. These findings indicate that the cytosolic components form an adaptive regulatory interface, which regulates T3SS activity in response to environmental conditions.

Complete Genome Sequences of Bacillus Bacteriophages Wes44 and Carmen17.

Wes44 and Carmen17 are siphoviruses that infect Bacillus thuringiensis DSM-350. Wes44 contains 42,248 base pairs and 54 predicted genes; Carmen17 contains 41,820 base pairs and 51 predicted genes. The genomes are 95% similar to each other and distantly related to Bacillus cereus bacteriophage PBC1.