A qepA8+ Shigella flexneri was cultured from the stool of a traveler returning from India and East Asia. This chromosomally encoded qepA variant, has a six-base insertion, and may have been mobilized as part of a complex IS1-mediated composite transposon including catA1, aadA1, and blaOXA-1. In laboratory E. coli, qepA8 alone only conferred decreased ciprofloxacin susceptibility; however, it may work in combination with additional mechanisms to confer clinical resistance.

Non-typhoidal Salmonella cause an estimated 1.4 million human illnesses, 26,000 hospitalizations and 400 deaths annually in the United States. Approximately 11% of these infections are attributed to animal contact. Reptiles and amphibians are known sources of salmonellosis; young children (aged <5 years) are disproportionately affected by reptile- and amphibian-associated salmonellosis (RAAS) outbreaks. We describe multistate RAAS outbreaks to characterize illnesses and inform prevention efforts. RAAS outbreaks were defined as ≥2 culture-confirmed human Salmonella infections with similar pulsed-field gel electrophoresis patterns and epidemiologic, laboratory or traceback evidence linking them to a common reptile/amphibian exposure. Data sources included the Animal Contact Outbreak Surveillance System; CDC Outbreak Response and Prevention Branch's outbreak management database; PulseNet, the national molecular subtyping network for foodborne disease surveillance in the United States; and the National Antimicrobial Resistance Monitoring System. Twenty-six RAAS outbreaks were reported during 2009–2018, resulting in 1465 illnesses and 306 hospitalizations. The outbreaks were associated with turtles (19), lizards (5), snakes (1) and frogs (1). Sixteen (61.5%) outbreaks were linked to small turtles (<4 inches), resulting in 914 illnesses. Forty-nine percent of outbreak-associated patients were aged <5 years. Of 362 patients/caregivers interviewed, 111 (30.7%) were aware that reptiles/amphibians can carry Salmonella. Among 267 patient isolates with antimicrobial susceptibility information, 20 (7.5%) were non-susceptible to ≥1 antibiotic used to treat human salmonellosis. RAAS outbreaks result in considerable morbidity, particularly among young children. Illnesses linked to small turtles are preventable through education, targeted outreach to caregivers and paediatricians, and when appropriate, enforcement. Historically, individual states and jurisdictions have enforced existing or promulgated new authorities to address outbreaks. Preventing future RAAS outbreaks requires addressing challenges related to the illegal sale/distribution of small turtles; and for legal reptile sales, providing information on RAAS risk to consumers at point of sale to support informed pet ownership decisions. Published 2022. This article is a U.S. Government work and is in the public domain in the USA. Zoonoses and Public Health published by Wiley-VCH GmbH.

A multidrug-resistant Salmonella enterica serotype Anatum strain reported in Taiwan was isolated in the United States from patients and from seafood imported from Asia. Isolates harbored 11 resistance determinants, including quinolone and inducible cephalosporin resistance genes. Most patients had traveled to Asia. These findings underscore the need for global One Health resistance surveillance.

In 2017, state health departments notified the Centers for Disease Control and Prevention about 4 patients with shigellosis who experienced persistent illness after treatment with oral third-generation cephalosporins. Given increasing antibiotic resistance among Shigella, these cases highlight the need to evaluate the efficacy of oral cephalosporins for shigellosis.

Enterobacteriaceae, quinolone resistance is largely attributed to mutations in the quinolone resistance-determining regions (QRDR) of gyrA, gyrB, parC, and parE, and plasmid-italiciated quinolone resistance (PMQR) genes (e.g., qnr genes, aac(6')-Ib-cr, or qepA).....

Orientia tsutsugamushi (Ots) frequently causes severe scrub typhus infections in the Asia-Pacific region. Korean investigators have demonstrated that Ots encodes five different autotransporter domain (ATD) proteins (ScaA-ScaE). ScaA functions as an adhesin and confers protective immunity in a lethal mouse model of Ots infection. Specific antibodies are detected against ScaA and ScaC in Korean scrub typhus patients. However, there is limited data on the distribution of the Sca protein genes in diverse isolates of Ots. By BLAST analysis with the conserved beta barrel autotransporter domain (ATD) regions of the sca proteins, we discovered a sixth gene scaF among 3 of 10 new partial Ots genome sequences available at NCBI GenBank (Sido, Karp, AFSC7). We designed two to seven specific TaqMan assays to detect the ATD for each of the six sca genes. The TaqMan assays among those for each sca gene which gave the greatest sensitivity and linearity with DNA log dilutions were then used for screening DNAs from Ots isolates grown in L929 mouse cells for sca genes. The sca prevalence survey was performed for all six sca genes with 178 DNAs from isolates from 12 countries. The survey results were confirmed by conventional PCR with primers from conserved regions of the passenger domains (PD) and ATD of the sca proteins. The ATD was highly conserved between the DNAs of different genotypes compared to the sca PD but each TaqMan assay was sca specific. The percentage positivity for 56 kDa and scaA genes in the 178 DNAs using Ha primers was 59.6% and 62.4%, respectively. Our scaA conventional ATD PCR assay was positive in 98.3% but scaA was present in all 178 DNAs (100%) by ATD TaqMan. scaB, scaC, scaD, scaE and scaF were detected in 33.7%, 97.8%, 93.8%, 97.2% and 43.3% isolates by ATD TaqMan, respectively. The ATDs of Ots sca genes are thus sufficiently conserved between different genotypes for molecular assay design. Four sca genes are widely distributed among diverse Ots isolates from diverse geographical areas. scaB and scaF were detected in fewer Ots isolates and absent from some available genome sequences. Whether the utility of the ScaA, ScaC, ScaD, and ScaE antigenic passenger protein domains exceeds that of the mixed 56 kDa type surface antigens of Ots now used in combination diagnostic assays needs to be determined before they can be considered as suitable alternative serological antigens for diagnosis of scrub typhus.

Invasive Salmonella infections in adults are commonly treated with fluoroquinolones, a critically important antimicrobial class. Historically, quinolone resistance was the result of chromosomal mutations, but plasmid-mediated quinolone resistance (PMQR) has emerged and is increasingly being reported in Enterobacteriaceae worldwide. PMQR may facilitate the spread of quinolone resistance, lead to higher-level quinolone resistance, and make infections harder to treat. To better understand the epidemiology of PMQR in non-typhoidal Salmonella causing human infections in the United States, we looked at trends in quinolone resistance among isolates submitted to the Centers for Disease Control and Prevention. We reviewed demographic, exposure and outcome information for patients with isolates having a PMQR-associated phenotype during 2008-2014 and tested isolates for quinolone resistance mechanisms. We found that PMQR is emerging among non-typhoidal Salmonella causing human infections in the United States and that international travel, reptile and amphibian exposure, and food are likely sources of human infection.

Newport is the third most common Salmonella enterica serotype identified among the estimated 1.2 million human salmonellosis infections occurring annually in the United States. Risk factors for infection and food items implicated in outbreaks vary by antimicrobial resistance pattern. We conducted a descriptive analysis of data from four enteric disease surveillance systems capturing information on incidence, demographics, seasonality, geographic distribution, outbreaks, and antimicrobial resistance of Newport infections over a 10-year period from 2004 through 2013. Incidence increased through 2010, then declined to rates similar to those in the early years of the study. Incidence was highest in the South and among children <5 years old. Among isolates submitted for antimicrobial susceptibility testing, 88% were susceptible to all antimicrobials tested (pansusceptible) and 8% were resistant to at least seven agents, including ceftriaxone. Rates of pansusceptible isolates were also highest in the South and among young children, particularly in 2010. Pansusceptible strains of Newport have been associated with produce items and environmental sources, such as creek water and sediment. However, the role of environmental transmission of Newport in human illness is unclear. Efforts to reduce produce contamination through targeted legislation, as well as collaborative efforts to identify sources of contamination in agricultural regions, are underway.

Nontyphoidal Salmonella (NTS) causes an estimated 1.2 million illnesses, 23,000 hospitalizations, and 450 deaths each year in the United States. Decreased susceptibility to ciprofloxacin (DSC) has historically been associated with chromosomal mutations (QRDR), but plasmid-mediated quinolone resistance (PMQR) genes are increasing. To investigate DSC among serotype Newport, we examined 40 isolates with DSC from 1996-2016. Thirty isolates (71%) contained the PMQR gene, qnrB, and eight isolates (19%) contained a QRDR.....

Drug-resistant bacterial infections pose a serious and growing public health threat globally. In this review, we describe the role of the National Antimicrobial Resistance Monitoring System (NARMS) in providing data that help address the resistance problem and show how such a program can have broad positive impacts on public health. NARMS was formed two decades ago to help assess the consequences to human health arising from the use of antimicrobial drugs in food animal production in the United States. A collaboration among the Centers for Disease Control and Prevention, the U.S. Food and Drug Administration, the United States Department of Agriculture, and state and local health departments, NARMS uses an integrated "One Health" approach to monitor antimicrobial resistance in enteric bacteria from humans, retail meat, and food animals. NARMS has adapted to changing needs and threats by expanding surveillance catchment areas, examining new isolate sources, adding bacteria, adjusting sampling schemes, and modifying antimicrobial agents tested. NARMS data are not only essential for ensuring that antimicrobial drugs approved for food animals are used in ways that are safe for human health but they also help address broader food safety priorities. NARMS surveillance, applied research studies, and outbreak isolate testing provide data on the emergence of drug-resistant enteric bacteria; genetic mechanisms underlying resistance; movement of bacterial populations among humans, food, and food animals; and sources and outcomes of resistant and susceptible infections. These data can be used to guide and evaluate the impact of science-based policies, regulatory actions, antimicrobial stewardship initiatives, and other public health efforts aimed at preserving drug effectiveness, improving patient outcomes, and preventing infections. Many improvements have been made to NARMS over time and the program will continue to adapt to address emerging resistance threats, changes in clinical diagnostic practices, and new technologies, such as whole genome sequencing.

BACKGROUND: Ceftriaxone resistance in Salmonella is a serious public health threat. Ceftriaxone is commonly used to treat severe Salmonella infections, especially in children. Identifying the sources and drivers of ceftriaxone resistance among nontyphoidal Salmonella is crucial. MATERIALS AND METHODS: The National Antimicrobial Resistance Monitoring System (NARMS) tracks antimicrobial resistance in foodborne and other enteric bacteria from humans, retail meats, and food animals. We examined NARMS data reported during 1996-2013 to characterize ceftriaxone-resistant Salmonella infections in humans. We used Spearman rank correlation to examine the relationships between the annual percentage of ceftriaxone resistance among Salmonella isolates from humans with isolates from retail meats and food animals. RESULTS: A total of 978 (2.9%) of 34,100 nontyphoidal Salmonella isolates from humans were resistant to ceftriaxone. Many (40%) ceftriaxone-resistant isolates were from children younger than 18 years. Most ceftriaxone-resistant isolates were one of three serotypes: Newport (40%), Typhimurium (26%), or Heidelberg (12%). All were resistant to other antimicrobials, and resistance varied by serotype. We found statistically significant correlations in ceftriaxone resistance between human and ground beef Newport isolates (r = 0.83), between human and cattle Typhimurium isolates (r = 0.57), between human and chicken Heidelberg isolates (r = 0.65), and between human and turkey Heidelberg isolates (r = 0.67). CONCLUSIONS: Ceftriaxone resistance among Salmonella Newport, Typhimurium, and Heidelberg isolates from humans strongly correlates with ceftriaxone resistance in isolates from ground beef, cattle, and poultry, respectively. These findings support other lines of evidence that food animals are important reservoirs of ceftriaxone-resistant Salmonella that cause human illness in the United States.

INTRODUCTION: Salmonella causes an estimated 100,000 antimicrobial-resistant infections annually in the United States. Salmonella antimicrobial resistance may result in bacteremia and poor outcomes. We describe antimicrobial resistance among nontyphoidal Salmonella blood isolates using data from the National Antimicrobial Resistance Monitoring System. METHODS: Human nontyphoidal Salmonella isolates from 2003-2013 were classified as fully susceptible, resistant to ≥1 antimicrobial agent, or resistant to a first-line agent. Logistic regression was used to compare resistance patterns, serotypes, and patient characteristics for Salmonella isolated from blood vs. stool and to determine resistance trends over time. RESULTS: Approximately 20% of blood isolates had antimicrobial resistance. Bacteremia was associated with male sex, age ≥65 years, and specific serotypes. Blood isolates were more likely to be resistant to ≥1 agent for serotypes Enteritidis, Javiana, Panama, and Typhimurium. Blood isolates were most commonly resistant to tetracycline (19%), and more likely resistant to a first-line agent (OR, 1.81; 95% CI, 1.56-2.11) than stool isolates. Ceftriaxone resistance increased in blood isolates from 2003-2013 (OR, 1.12; 95% CI, 1.02-1.22). CONCLUSION: Resistance to first-line treatment agents in Salmonella bacteremia patients is a concern for public health and for informing clinical decisions. Judicious antimicrobial use is crucial to limit resistance.

We found a strong association between nalidixic acid (NA)-resistant Salmonella serotype Enteritidis (SE) infections in the United States and recent international travel.

Scrub typhus, caused by infection with Orientia tsutsugamushi, is probably the most common severe rickettsial disease. Early diagnosis followed by treatment with antibiotics such as doxycycline or chloramphenicol usually quickly decreases fever in patients, and they often recover well from other symptoms of the disease. However, poorly responsive cases have been reported from northern Thailand and southern India. In order to identify protein factors that may be partially responsible for differential drug sensitivity of isolates of Orientia, we compared the protein profiles of doxycycline sensitive (Karp) versus (vs.) insensitive (AFSC4 and AFSC7) isolates. Tryptic peptides from both total water-soluble proteins and from protein spots separated by 2D-PAGE were analyzed using LC-MS/MS. The identity of each protein was established using the published genomic sequence of Boryong strain O. tsutsugamushi. The profiles of protein released into water from these isolates were quite different. There were 10 proteins detected only in AFSC4, 3 only in Karp, and 1 only in AFSC7. Additionally, there were 2 proteins not detected only in AFSC4, 4 not found only in Karp, and 3 not found only in AFSC-7. A comparison of 2D-PAGE protein profiles of drug sensitive strain versus (vs.) insensitive isolates has led to the identification of 14 differentially expressed or localized proteins, including elongation factor Ts and Tu, DNA-directed RNA polymerase alpha-subunit, ATP synthase beta-subunit, and several hypothetical proteins. These data confirm the tremendous proteomic diversity of isolates of Orientia and suggest that drug insensitivity in this species may arise from multiple mechanisms.