We describe a field investigation in New England that identified the emergence and epidemiology of new strains of multidrug-resistant Salmonella, Newport-MDRAmpC, and summarize the Center for Disease Control and Prevention's surveillance data for these infections. In Massachusetts, the prevalence of Newport-MDRAmpC among Salmonella serotype Newport isolates obtained from humans increased from 0% (0/14) in 1998 to 53% (32/60) in 2001 (P<.001). In a retrospective case-control study, infection with Newport-MDRAmpC was domestically acquired and was associated with exposure to a dairy farm. Isolates from both humans and cattle had indistinguishable or closely related antibiograms and pulsed-field gel electrophoresis patterns. Nationally, the prevalence of ceftriaxone-resistant Salmonella increased from 0.5% in 1998 to 2.4% in 2001; 85% of the isolates in 2001 were Newport-MDRAmpC, and at least 27 states have isolated these strains from humans, cattle, or ground beef. These data document the widespread emergence of Newport-MDRAmpC strains in the United States and show that the 5-fold increase in the prevalence of Salmonella resistant to expanded-spectrum cephalosporins, between 1998 and 2001, is primarily due to the emergence of Newport-MDRAmpC strains.

For Salmonella enterica serovar Enteritidis, 85% of isolates can be classified into 5 pulsed-field gel electrophoresis (PFGE) types. However, PFGE has limited discriminatory power for outbreak detection. Although whole-genome sequencing has been found to improve discrimination of outbreak clusters, whether this procedure can be used in real-time in a public health laboratory is not known. Therefore, we conducted a retrospective and prospective analysis. The retrospective study investigated isolates from 1 confirmed outbreak. Additional cases could be attributed to the outbreak strain on the basis of whole-genome data. The prospective study included 58 isolates obtained in 2012, including isolates from 1 epidemiologically defined outbreak. Whole-genome sequencing identified additional isolates that could be attributed to the outbreak, but which differed from the outbreak-associated PFGE type. Additional putative outbreak clusters were detected in the retrospective and prospective analyses. This study demonstrates the practicality of implementing this approach for outbreak surveillance in a state public health laboratory.

Individual or multiple resistance to clindamycin, tetracycline, erythromycin, levofloxacin, or mupirocin was detected in a large proportion of methicillin-resistant Staphylococcus aureus pulsed-field type USA300 isolates collected at an ambulatory health center in Boston. The clindamycin, tetracycline, and mupirocin resistance genes identified in these isolates are commonly associated with plasmids.

The family Paramyxoviridae comprises a diverse group of viruses that includes several important human and veterinary pathogens. Members of this family have a non-segmented, single-stranded, negative sense RNA genome, a conserved gene order, and a similar replication strategy. Paramyxoviruses are divided into two subfamilies, Paramyxovirinae and Pneumovirinae, which comprise five genera and two genera, respectively. Viruses in each genus have developed strategies to circumvent the interferon (IFN) response by using a diverse array of proteins that are encoded within the phosphoprotein genes of the Paramyxovirinae or non-structural genes of the Pneumovirinae. This review focuses on the specific roles that these viral proteins play in the inhibition of IFN signaling and, to a lesser extent, on the mechanisms by which these proteins inhibit the induction pathways of IFN. An improved understanding of the interactions between viral proteins and the host innate immune response is critical to achieving a thorough comprehension of the pathogenesis of this important group of viruses. Hopefully this knowledge will support the development of more targeted vaccines and therapeutics to better prevent and control viral infection.