OBJECTIVES: . The United States Centers for Disease Control and Prevention (CDC) conducts active surveillance for typhoid fever cases caused by Salmonella enterica serovar Typhi (Typhi). Here we describe the characteristics of the first two cases of mph(A)-positive azithromycin-resistant Typhi identified through US surveillance. METHODS: . Isolates were submitted to public health laboratories, sequenced, and screened for antimicrobial resistance determinants and plasmids, as part of CDC PulseNet's routine genomic surveillance. Antimicrobial susceptibility testing and long-read sequencing were also performed. Basic case information (age, sex, travel, outcome) was collected through routine questionnaires; additional epidemiological data was requested through follow-up patient interviews. RESULTS: . The patients are related and both reported travel to India (overlapping travel dates) before illness onset. Both Typhi genomes belong to the GenoTyphi lineage 4.3.1.1 and carry the azithromycin-resistance gene mph(A) on a PTU-FE (IncFIA/FIB/FII) plasmid. These strains differ genetically from mph(A)-positive Typhi genomes recently reported from Pakistan, suggesting independent emergence of azithromycin resistance in India. CONCLUSIONS: . Cases of typhoid fever caused by Typhi strains resistant to all available oral treatment options are cause for concern and support the need for vaccination of travelers to Typhi endemic regions. US genomic surveillance serves as an important global sentinel for detection of strains with known and emerging antimicrobial resistance profiles, including strains from areas where routine surveillance is not conducted.

Melioidosis, caused by Burkholderia pseudomallei, is a rare but potentially fatal bacterial disease endemic to tropical and subtropical regions worldwide. It is typically acquired through contact with contaminated soil or fresh water. Before this investigation, B. pseudomallei was not known to have been isolated from the environment in the continental United States. Here, we report on three patients living in the same Mississippi Gulf Coast county who presented with melioidosis within a 3-year period. They were infected by the same Western Hemisphere B. pseudomallei strain that was discovered in three environmental samples collected from the property of one of the patients. These findings indicate local acquisition of melioidosis from the environment in the Mississippi Gulf Coast region.

During November 19-21, 2021, an indoor convention (event) in New York City (NYC), was attended by approximately 53,000 persons from 52 U.S. jurisdictions and 30 foreign countries. In-person registration for the event began on November 18, 2021. The venue was equipped with high efficiency particulate air (HEPA) filtration, and attendees were required to wear a mask indoors and have documented receipt of at least 1 dose of a COVID-19 vaccine.* On December 2, 2021, the Minnesota Department of Health reported the first case of community-acquired COVID-19 in the United States caused by the SARS-CoV-2 B.1.1.529 (Omicron) variant in a person who had attended the event (1). CDC collaborated with state and local health departments to assess event-associated COVID-19 cases and potential exposures among U.S.-based attendees using data from COVID-19 surveillance systems and an anonymous online attendee survey. Among 34,541 attendees with available contact information, surveillance data identified test results for 4,560, including 119 (2.6%) persons from 16 jurisdictions with positive SARS-CoV-2 test results. Most (4,041 [95.2%]), survey respondents reported always wearing a mask while indoors at the event. Compared with test-negative respondents, test-positive respondents were more likely to report attending bars, karaoke, or nightclubs, and eating or drinking indoors near others for at least 15 minutes. Among 4,560 attendees who received testing, evidence of widespread transmission during the event was not identified. Genomic sequencing of 20 specimens identified the SARS-CoV-2 B.1.617.2 (Delta) variant (AY.25 and AY.103 sublineages) in 15 (75%) cases, and the Omicron variant (BA.1 sublineage) in five (25%) cases. These findings reinforce the importance of implementing multiple, simultaneous prevention measures, such as ensuring up-to-date vaccination, mask use, physical distancing, and improved ventilation in limiting SARS-CoV-2 transmission, during large, indoor events.(†).