In this study, we describe a multiplex PCR to detect a AGC3ACC (serine to threonine) mutation in the katG gene and a ؊15 C-to-T substitution (inhA C؊15T Currently, throughout the world, isoniazid (INH) and rifampin (RIF) together represent the backbone of short-course chemotherapy for Mycobacterium tuberculosis infections. The number of multidrug-resistant strains of M. tuberculosis, defined as resistant to INH and RIF, has been increasing over the years, and several outbreaks have been reported (5, 9, 24). The development of resistance to these two drugs reduces the efficacy of standard antituberculosis (anti-TB) treatment to 77%. It is very important, therefore, to identify these strains as soon as possible to allow for adjustments in treatment and to minimize the transmission of drug-resistant strains. Phenotypic drug susceptibility testing by conventional methods on solid media (6, 8) requires 10 to 30 days after the primary culture has been isolated. This time can be reduced by the use of rapid methods such as BACTEC, which requires 5 to 10 days.)Resistance to RIF has been shown to be caused by an alteration of the ␤ subunit of RNA polymerase, which is encoded by the rpoB gene. More than 95% of RIF-resistant strains are associated with mutations within an 81-bp region of the rpoB gene (encoding the RNA polymerase ␤ subunit). Specific mutations, insertions, and deletions have been described in several countries by several authors, and this 81-bp region has been termed the rifampin resistance determinant region (7,14,20,26,27,30). Numerous methods exist to detect resistance to rifampin (10,12,18,23).In contrast, resistance to INH is more complicated, as mutations in several genes can lead to drug resistance. For most INH-resistant strains, mutations have been found in two genes, i.e., the katG gene, encoding catalase-peroxidase (31), and the mabA-inhA regulon (4), encoding a target of activated prodrug, enoyl-acyl carrier protein reductase (1-3, 11, 13, 15, 17, 21, 27). For some other INH-resistant strains, however, mutations in the ahpC promoter region (located in the 105-bp oxyR-ahpC intergenic region) or within the ␤-ketocyl acyl carrier protein synthase gene kasA have also been reported (19,25). Most studies have examined the mutations present in these genes by DNA sequencing or analyses of a portion of the katG gene after PCR amplification and digestion with the restriction enzyme MspI or SatI (2, 3, 17).Molecular methods have been developed to detect resistance to INH and RIF as an alternative to conventional tests because of their ability to provide results rapidly. Upon the elucidation of the genes involved in resistance to RIF and INH, several studies describing various PCR-based molecular genetic techniques for the detection of resistance were published (12).In the present study, we report a simple, rapid, and inexpensive assay based on allele-specific PCR methodology targeting an AGC3ACC mutation in the katG gene and an inhA CϪ15T mutation in the regulatory region of the mabA-inhA operon to detect...

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We describe a Salmonella Poona outbreak involving 31 infant cases in France. Following outbreak detection on 18 January 2019, consumption of rice-based infant formula manufactured at a facility in Spain was identified as the probable cause, leading to a recall on 24 January. Whole genome sequencing analysis linked present outbreak isolates to a 2010–11 S. Poona outbreak in Spain associated with formula manufactured in the same facility, indicating a persistent source of contamination.