Bacillus anthracis causes anthrax through virulence factors encoded on two plasmids. However, non-B. anthracis organisms within the closely related, environmentally ubiquitous Bacillus cereus group (BCG) may cause an anthrax-like disease in humans through the partial adoption of anthrax-associated virulence genes, challenging the definition of anthrax disease. To elucidate these phenomena and their evolutionary past, we performed whole-genome sequencing on non-anthracis BCG isolates, including 93 archival (1967-2003) and 5 contemporary isolates (2019-2023). We produced annotated genomic assemblies and performed a pan-genome analysis to identify evidence of virulence gene homology and virulence gene acquisition by linear inheritance or horizontal gene transfer. At least one anthrax-associated virulence gene was annotated in ten isolates. Most homologous sequences in archival isolates showed evidence of pseudogenization and subsequent gene loss. The presence or absence of accessory genes, including anthrax-associated virulence genes, aligned with the phylogenetic structure of the BCG core genome. These findings support the hypothesis that anthrax-associated virulence genes were inherited from a common ancestor in the BCG and were retained or lost across different lineages, and contribute to a growing body of work informing public health strategies related to anthrax surveillance and identification.

This review serves as an update to the previous Nocardia review by Brown-Elliott et al. published in 2006 (B. A. Brown-Elliott, J. M. Brown, P. S. Conville, and R. J. Wallace. Jr., Clin Microbiol Rev 19:259-282, 2006, https://doi.org/10.1128/CMR.19.2.259-282.2006). Included is a discussion on the taxonomic expansion of the genus, current identification methods, and the impact of new technology (including matrix-assisted laser desorption ionization-time of flight [MALDI-TOF] and whole genome sequencing) on diagnosis and treatment. Clinical manifestations, the epidemiology, and geographic distribution are briefly discussed. An additional section on actinomycotic mycetoma is added to address this often-neglected disease.

BACKGROUND: During an anthrax mass casualty event, prompt identification of patients with anthrax meningitis is important. Previous research has suggested use of a screening tool based on neurological symptoms and signs. METHODS: Using historical anthrax patient data from 1880 through 2018, we analyzed risk factors for meningitis. We developed lists of symptoms and signs (ie, algorithms) for predicting meningitis with high sensitivity and specificity. We evaluated both single and paired algorithms as screening tools. RESULTS: A single algorithm with 1 or more neurological symptoms or signs identifying patients with likely meningitis achieved high sensitivity (86%; 95% confidence interval [CI], 71%-100%) and specificity (90%; 95% CI, 82%-98%). Pairing algorithms with the same symptoms and signs (severe headache, altered mental status, meningeal signs, and "other neurological deficits") improved specificity (99%; 95% CI, 97%-100%) but left 17.3% of patients in a middle "indeterminate" meningitis category and in need of additional diagnostic testing to determine likely meningitis status. Pairing algorithms with differing symptoms and signs also improved specificity over the single algorithm (92%; 95% CI, 85%-99%) but categorized just 2.5% of patients as indeterminate. CONCLUSIONS: Our study confirms prior research suggesting quick and reliable assessment of patients for anthrax meningitis is possible based on the presence or absence of certain symptoms and signs. A single algorithm was adequate; however, if we assumed low-resource diagnostic testing was feasible for some patients, pairing algorithms improved specificity. Pairing algorithms with differing symptoms and signs minimized the proportion of patients requiring additional diagnostics.

BACKGROUND: Cutaneous anthrax accounts for approximately 95% of anthrax cases worldwide. About 24% of untreated patients die, and many cases are complicated by meningitis. Here, we explore clinical features of cutaneous disease associated with poor outcomes. METHODS: A systematic review identified 303 full-text articles published from 1950 through 2018 that met predefined inclusion criteria. Cases were abstracted, and descriptive analyses and univariate logistic regression were conducted to identify prognostic indicators for cutaneous anthrax. RESULTS: Of 182 included patients, 47 (25.8%) died. Previously reported independent predictors for death or meningitis that we confirmed included fever or chills; nausea or vomiting; headache; severe headache; nonheadache, nonmeningeal signs; leukocytosis; and bacteremia. Newly identified predictors included anxiety, abdominal pain, diastolic hypotension, skin trauma, thoracic edema, malignant pustule edema, lymphadenopathy, and evidence of coagulopathy (all with P < .05). CONCLUSIONS: We identified patient presentations not previously associated with poor outcomes.

Abstract Bacillus cereus group bacteria containing the anthrax toxin genes can cause fatal anthrax pneumonia in welders. Two welder's anthrax cases identified in 2020 were investigated to determine the source of each patient's exposure. Environmental sampling was performed at locations where each patient had recent exposure to soil and dust. Samples were tested for the anthrax toxin genes by real-time PCR, and culture was performed on positive samples to identify whether any environmental isolates matched the patient's clinical isolate. A total of 185 environmental samples were collected in investigation A for patient A and 108 samples in investigation B for patient B. All samples from investigation B were real-time PCR-negative, but 14 (8%) samples from investigation A were positive, including 10 from patient A's worksite and 4 from his work-related clothing and gear. An isolate genetically matching the one recovered from patient A was successfully cultured from a worksite soil sample. All welder's anthrax cases should be investigated to determine the source of exposure, which may be linked to their worksite. Welding and metalworking employers should consider conducting a workplace hazard assessment and implementing controls to reduce the risk of occupationally associated illnesses including welder's anthrax.

Anthrax has been feared for its high mortality in animals and humans for centuries. The etiologic agent is considered a potentially devastating bioweapon, and since 1876-when Robert Koch demonstrated that Bacillus anthracis caused anthrax-it has been considered the sole cause of the disease. Anthrax is, however, a toxin-mediated disease. The toxins edema toxin and lethal toxin are formed from protein components encoded for by the pXO1 virulence plasmid present in pathogenic B. anthracis strains. However, other members of the Bacillus cereus group, to which B. anthracis belongs, have recently been shown to harbor the pXO1 plasmid and produce anthrax toxins. Infection with these Bacillus cereus group organisms produces a disease clinically similar to anthrax. This suggests that anthrax should be defined by the exotoxins encoded for by the pXO1 plasmid rather than the bacterial species it has historically been associated with, and that the definition of anthrax should be expanded to include disease caused by any member of the B. cereus group containing the toxin-producing pXO1 plasmid or anthrax toxin genes specifically.

While Bacillus cereus typically causes opportunistic infections in humans, within the last three decades, severe and fatal infections caused by isolates of the B. cereus group harboring anthrax toxin genes have been reported in the United States. From 1994 to 2020, seven cases of anthrax-like illness resulting from these isolates have been identified. With one exception, the cases have occurred in the Gulf States region of the United States among metalworkers. We aimed to develop an ecological niche model (ENM) to estimate a spatial area conducive to the survival of these organisms based on the presence of known human infections and environmental variables. The estimated ecological niche for B. cereus was modeled with the maximum entropy algorithm (Maxent). Environmental variables contributing most to the model were soil characteristics (cation exchange capacity, carbon content, soil pH), temperature, enhanced vegetation index (EVI), and land surface temperature (LST). Much of the suitable environments were located throughout the Gulf Coast Plain, Texas Backland Prairies, East Central Texas Plains, Edwards Plateau, Cross Timbers, Mississippi Alluvial Plain, and Central Great Plains. These findings may provide additional guidance to narrow potential risk areas to efficiently communicate messages to metalworkers and potentially identify individuals who may benefit from the anthrax vaccine.

In 2020, CDC confirmed two cases of pneumonia (one fatal) in welders caused by rare Bacillus cereus group bacteria containing anthrax toxin genes typically associated with Bacillus anthracis. B. cereus group bacteria are gram-positive facultative anaerobes, often toxin-producing, that are ubiquitous in the environment and reside naturally in soil and dust (1). B. cereus can also be found in food, and although infection typically causes illnesses characterized by diarrhea or vomiting, B. cereus can have other clinical manifestations (e.g., pulmonary, ocular, or cutaneous). Among seven persons in the United States reported to be infected with B. cereus group bacteria containing anthrax toxin genes resulting in pneumonia since 1994, five patients died and two had critical illness with prolonged hospitalization and recovery (2–5). All persons with pneumonia were welders or other metalworkers who had worked in Louisiana or Texas (Table). In addition to the seven pneumonia cases, a cutaneous infection with B. cereus group bacteria containing anthrax toxin genes has been reported in a patient with an anthrax eschar in Florida.†

The human cutaneous anthrax case-fatality rate is ≈1% when treated, 5%-20% when untreated. We report high case-fatality rates (median 35.0%; 95% CI 21.1%-66.7%) during 2005-2016 linked to livestock handling in northern Ghana, where veterinary resources are limited. Livestock vaccination and access to human treatment should be evaluated.

The Global Mycetoma Working Group (GMWG) was formed in January 2018 in response to the declaration of mycetoma as a neglected tropical disease (NTD) by the World Health Assembly. The aim of the working group is to connect experts and public health practitioners around the world to accelerate mycetoma prevention activities and reduce the impact of mycetoma on patients, healthcare providers and society in the endemic regions. The working group has made tangible contributions to mycetoma programming, awareness and coordination among scientists, clinicians and public health professionals. The group's connectivity has enabled rapid response and review of NTD documents in development, has created a network of public health professionals to provide regional mycetoma expertise and has enabled mycetoma to be represented within broader NTD organizations. The GMWG will continue to serve as a hub for networking and building collaborations for the advancement of mycetoma clinical management and treatment, research and public health programming.

Background: Rat-bite fever is a rare disease associated with rat bites or direct/indirect rodent contact. Methods: We examined rat-bite fever and rat-bite injury diagnoses in the United States during 2001-2015. We analyzed national, state, and Indian Health Service healthcare encounter datasets for rat-bite fever and rat-bite injury diagnoses. We calculated average-annual encounter rates per 1 000 000 persons. Results: Nationally, the rat-bite fever Emergency Department visit rate was 0.33 (95% confidence interval [CI], 0.19-0.47) and the hospitalization rate was 0.20 (95% CI, 0.17-0.24). The rat-bite injury Emergency Department visit rate was 10.51 (95% CI, 10.13-10.88) and the hospitalization rate was 0.27 (95% CI, 0.23-0.30). The Indian Health Service Emergency Department/outpatient visit rate was 3.00 for rat-bite fever and 18.89 for rat-bite injury. The majority of rat-bite fever encounters were among individuals 0-19 years of age. Conclusions: Our results support the literature that rat-bite fever is rare and affects children and young adults. Targeted education could benefit specific risk groups.

INTRODUCTION: Anthrax is endemic in Georgia and recent outbreaks prompted a livestock-handler case-control study with a component to evaluate anthrax knowledge, attitudes, and practices (KAP) among livestock handlers or owners. METHODS: Cases were handlers of livestock with confirmed animal anthrax from June 2013-May 2015. Handlers of four matched unaffected animals were selected as controls, two from the same village as the case animal ("village control") and two from 3-10 km away ("area control"). Descriptive statistics were reported and conditional logistic regression was performed to estimate the magnitude of the association of cases with specific study KAP factors. RESULTS: Cases were more likely male, had lower level college education, less animal care experience, and provided more animal care to their cattle. Cases had lower odds of burying a suddenly dead animal compared to all controls (Odds Ratio [OR]: 0.32, 95% Confidence interval [CI]:0.12, 0.88) and area controls (OR: 0.32, 95% CI: 0.11, 0.91). On an 8-point knowledge scale, cases having an animal with anthrax had a 1.31 times greater knowledge score compared to all controls (95% CI: 1.03, 1.67). Cases had higher odds of ever having human anthrax or knowing another person who had anthrax compared to all controls (OR: 4.56, 95% CI: 1.45, 14.30) and area controls (OR: 7.16, 95% CI: 1.52, 33.80). DISCUSSION: Cases were more knowledgeable of anthrax and had better anthrax prevention practices, but these are likely a result of the case investigation and ring vaccination following the death of their animal. CONCLUSIONS: The findings reveal a low level of knowledge and practices related to anthrax control and prevention, and will guide educational material development to fill these gaps.

Background: Population exposure to Bacillus anthracis spores could cause mass casualties requiring complex medical care. Rapid identification of patients needing anthrax-specific therapies will improve patient outcomes and resource use. Objective: To develop a checklist that rapidly distinguishes most anthrax from nonanthrax illnesses on the basis of clinical presentation and identifies patients requiring diagnostic testing after a population exposure. Design: Comparison of published anthrax case reports from 1880 through 2013 that included patients seeking anthrax-related care at 2 epicenters of the 2001 U.S. anthrax attacks. Setting: Outpatient and inpatient. Patients: 408 case patients with inhalation, ingestion, and cutaneous anthrax and primary anthrax meningitis, and 657 control patients. Measurements: Diagnostic test characteristics, including positive and negative likelihood ratios (LRs) and patient triage assignation. Results: Checklist-directed triage without diagnostic testing correctly classified 95% (95% CI, 93% to 97%) of 353 adult anthrax case patients and 76% (CI, 73% to 79%) of 647 control patients (positive LR, 3.96 [CI, 3.45 to 4.55]; negative LR, 0.07 [CI, 0.04 to 0.11]; false-negative rate, 5%; false-positive rate, 24%). Diagnostic testing was needed for triage in up to 5% of case patients and 15% of control patients and improved overall test characteristics (positive LR, 8.90 [CI, 7.05 to 11.24]; negative LR, 0.06 [CI, 0.04 to 0.09]; false-negative rate, 5%; false-positive rate, 11%). Checklist sensitivity and specificity were minimally affected by inclusion of pediatric patients. Sensitivity increased to 97% (CI, 94% to 100%) and 98% (CI, 96% to 100%), respectively, when only inhalation anthrax cases or higher-quality case reports were investigated. Limitations: Data on case patients were limited to nonstandardized, published observational reports, many of which lacked complete data on symptoms and signs of interest. Reporting bias favoring more severe cases and lack of intercurrent outbreaks (such as influenza) in the control populations may have improved test characteristics. Conclusion: A brief checklist covering symptoms and signs can distinguish anthrax from other conditions with minimal need for diagnostic testing after known or suspected population exposure. Primary Funding Source: U.S. Department of Health and Human Services.

Naturally occurring anthrax disproportionately affects the health and economic welfare of poor, rural communities in anthrax-endemic countries. However, many of these countries have limited anthrax prevention and control programs. Effective prevention of anthrax outbreaks among humans is accomplished through routine livestock vaccination programs and prompt response to animal outbreaks. The Centers for Disease Control and Prevention uses a 2-phase framework when providing technical assistance to partners in anthrax-endemic countries. The first phase assesses and identifies areas for improvement in existing human and animal surveillance, laboratory diagnostics, and outbreak response. The second phase provides steps to implement improvements to these areas. We describe examples of implementing this framework in anthrax-endemic countries. These activities are at varying stages of completion; however, the public health impact of these initiatives has been encouraging. The anthrax framework can be extended to other zoonotic diseases to build on these efforts, improve human and animal health, and enhance global health security.

Anthrax postexposure prophylaxis (PEP) was recommended to 42 people after a laboratory incident that involved potential aerosolization of Bacillus anthracis spores in 2 laboratories at the Centers for Disease Control and Prevention in 2014. At least 31 (74%) individuals who initiated PEP did not complete either the recommended 60 days of antimicrobial therapy or the 3-dose vaccine regimen. Among the 29 that discontinued the antimicrobial component of PEP, most (38%) individuals discontinued PEP because of their low perceived risk of infection; 9 (31%) individuals discontinued prophylaxis due to PEP-related minor adverse events, and 10% cited both low risk and adverse events as their reason for discontinuation. Most minor adverse events reported were gastrointestinal complaints, and none required medical attention. Individuals taking ciprofloxacin were twice as likely (RR = 2.02, 95% CI = 1.1-3.6) to discontinue antimicrobial prophylaxis when compared to those taking doxycycline. In the event anthrax PEP is recommended, public health messages and patient education materials will need to address potential misconceptions regarding exposure risk and provide information about possible adverse events in order to promote PEP adherence.

BACKGROUND: In 2012, the Alaska Section of Epidemiology investigated personnel potentially exposed to a Brucella suis isolate as it transited through three laboratories. METHODS: We summarize the first implementation of the United States Centers for Disease Control and Prevention 2013 revised recommendations for monitoring such exposures: (1) risk classification; (2) antimicrobial postexposure prophylaxis; (3) serologic monitoring; and (4) symptom surveillance. RESULTS: Over 30 people were assessed for exposure and subsequently monitored for development of illness. No cases of laboratory-associated brucellosis occurred. Changes were made to gaps in laboratory biosafety practices that had been identified in the investigation. CONCLUSION: Achieving full compliance for the precise schedule of serologic monitoring was challenging and resource intensive for the laboratory performing testing. More refined exposure assessments could inform decision making for follow-up to maximize likelihood of detecting persons at risk while not overtaxing resources.

Human Brucella canis infection incidence is unknown. Most identified cases are associated with pet dogs. Laboratory-acquired infections can occur following contact with Brucella spp. We identified a paediatric B. canis case, the source and other exposed persons. A 3-year-old New York City child with fever and dyspnoea was hospitalized for 48 h for bronchiolitis. After her admission, blood culture grew B. canis, she was prescribed anti-microbials and recovered. B. canis was also isolated from blood of the child's pet dog; these isolates were genetically similar. The dog originated from an Iowa breeding facility which was quarantined after identification of the dog's infection. Additionally, 31 laboratory workers were exposed and subsequently monitored for symptoms; 15 completed post-exposure prophylaxis. To our knowledge, this is the first report strongly suggesting B. canis zoonotic transmission to a child in the United States, and highlights the need for coordinated control policies to minimize human illness.

BACKGROUND: Melioidosis results from infection with Burkholderia pseudomallei, and is associated with case-fatality rates up to 40%. Early diagnosis and treatment with appropriate antimicrobials can improve survival rates. Fatal and non-fatal melioidosis cases were identified in Puerto Rico in 2010 and 2012, respectively, which prompted contact investigations to identify risk factors for infection and evaluate endemicity. METHODS: Questionnaires were administered and serum specimens were collected from co-workers, neighborhood contacts within 250 meters of both patients' residences, and injection drug use (IDU) contacts of the 2012 patient. Serum specimens were tested for evidence of prior exposure to B. pseudomallei by indirect hemagglutination assay. Neighborhood seropositivity results guided soil sampling to isolate B. pseudomallei. RESULTS: Serum specimens were collected from contacts of the 2010 (n=51) and 2012 (n=60) patients, respectively. No co-workers had detectable anti-B. pseudomallei antibody, whereas seropositive results among neighborhood contacts was 5% (n=2) for the 2010 patient and 23%(n=12) for the 2012 patient, as well as 2 of 3 IDU contacts for the 2012 case. Factors significantly associated with seropositivity were having skin wounds, sores, or ulcers (OR=4.6; 95% CI: 1.2-17.8) and IDU (OR=18.0; 95% CI: 1.6-194.0). B. pseudomallei was isolated from soil collected in the neighborhood of the 2012 patient. CONCLUSIONS: Taken together, isolation of B. pseudomallei from a soil sample and high seropositivity among patient contacts suggest at least regional endemicity of melioidosis in Puerto Rico. Increased awareness of melioidosis is needed to enable early case identification and early initiation of appropriate antimicrobial therapy.

A small percentage of persons with leptospirosis, a reemerging zoonosis, experience severe complications that require hospitalization. The number of leptospirosis cases in the United States is unknown. Thus, to estimate the hospitalization rate for this disease, we analyzed US hospital discharge records for 1998-2009 for the total US population by using the Nationwide Inpatient Sample. During that time, the average annual rate of leptospirosis-associated hospitalizations was 0.6 hospitalizations/1,000,000 population. Leptospirosis-associated hospitalization rates were higher for persons >20 years of age and for male patients. For leptospirosis-associated hospitalizations, the average age of patients at admission was lower, the average length of stay for patients was longer, and hospital charges were higher than those for nonleptospirosis infectious disease-associated hospitalizations. Educating clinicians on the signs and symptoms of leptospirosis may result in earlier diagnosis and treatment and, thereby, reduced disease severity and hospitalization costs.

We describe a periprosthetic Brucella abortus infection in a case-patient undergoing hip replacement revision surgery, and the subsequent investigation of laboratory and surgical staff exposures. Although exposures are rare, it is important to have infection prevention recommendations for surgical procedures among patients with suspected or unidentified Brucella spp. infection.

Five laboratory-acquired brucellosis (LAB) cases that occurred in the United States between 2008 and 2011 are presented. The Centers for Disease Control and Prevention (CDC) reviewed the recommendations published in 2008 and the published literature to identify strategies to further prevent LAB. The improved prevention strategies are described.

Brucellosis is a bacterial zoonotic disease which has been associated with laboratory-acquired infections. No recent reviews have addressed the characteristics of laboratory-acquired brucellosis (LAB). English-language literature was reviewed to identify reports of laboratory exposures to Brucella spp. and LAB cases between 1982 and 2007. Evaluation of twenty-eight case reports identified 167 potentially exposed laboratory workers of which 71 had LAB. Nine reports were identified that summarized an additional 186 cases of LAB. Only 18 (11%) exposures were due to laboratory accidents, 147 (88%) exposures were due to aerosolization of organisms during routine identification activities and 2 (1%) exposures were unknown. Brucella melitensis was the causative agent for 80% (135/167) of the exposures. Workers with high risk exposures were 9.3 times more likely to develop LAB than workers with low risk exposures (95% CI, 3.0-38.6; P<0.0001); they were also 0.009 times as likely to develop LAB if they took antimicrobial PEP than those who did not take PEP (95% CI, 0-0.042; P<0.0001). Median incubation period in case and summary reports was eight weeks (range 1-40 weeks). Antimicrobial PEP is effective in preventing LAB. The incubation period may be used to identify appropriate serological and symptom surveillance timeframes for exposed laboratory workers.