Anthrax: a disease in waiting?

Identification of Anthrax as the Cause of a Cluster of Unexplained Deaths, Uganda, 2023: The Role of Metagenomic Next-Generation Sequencing and Postmortem Specimens

Between April and November 2023, 27 unexplained human deaths that presented with swelling of the arms, skin sores with black centers, difficulty in breathing, obstructed swallowing, headaches, and other body aches were reported in Kyotera District, Uganda by the Public Health Emergency Operations Center. Subsequently, the death of cattle on farms and the consumption of carcass meat by some residents were also reported. Field response teams collected clinical/epidemiological data and autopsy samples to determine the cause of deaths. Metagenomic next-generation sequencing (mNGS) and target enrichment sequencing conducted on postmortem samples confirmed Bacillus anthracis, the etiological agent of anthrax disease, as the cause of the deaths. Applying mNGS to autopsy specimens is useful as a retrospective tool for identifying high-consequence pathogens during suspected outbreaks of unknown etiology.

Cutaneous Anthrax in a Farmer Man: A Case Report

Introduction:

Anthrax is an acute infection caused by Bacillus anthracis, an anaerobic, spore-forming, Gram-positive bacterium. Anthrax disease is a common disease among herbivores and humans that is transmitted to humans through direct contact with farm animals that are sick or have died of anthrax.

Case Summary:

A 43-year-old man having livestock as a profession had a cutaneous anthrax infection on the dorsal surface of his left thumb. The patient was infected with anthrax by slaughtering a sheep infected with Bacillus anthracis. He was treated with penicillin after an early diagnosis of anthrax bacillus.

Conclusion:

Anthrax infection is a highly contagious disease, and early detection is very important. There is a need to strengthen the health care system for farm animals and educate farmers on how not to consume the meat of diseased carcasses and how to dispose them of hygienically, especially in high-risk areas.

Aerosol-Transmitted Infections-a New Consideration for Public Health and Infection Control Teams

Since the emergence of the 2003 severe acute respiratory syndrome (SARS), the 2003 reemergence of avian A/H5N1, the emergence of the 2009 pandemic influenza A/H1N1, the 2012 emergence of Middle East respiratory syndrome (MERS), the 2013 emergence of avian A/H7N9 and the 2014 Ebola virus outbreaks, the potential for the aerosol transmission of infectious agents is now routinely considered in the investigation of any outbreak. Although many organisms have traditionally been considered to be transmitted by only one route (e.g. direct/indirect contact and/or faecal-orally), it is now apparent that the aerosol transmission route is also possible and opportunistic, depending on any potentially aerosol-generating procedures, the severity of illness and the degree and duration of pathogen-shedding in the infected patient, as well as the environment in which these activities are conducted.This article reviews the evidence and characteristics of some of the accepted (tuberculosis, measles, chickenpox, whooping cough) and some of the more opportunistic (influenza, Clostridium difficile, norovirus) aerosol-transmitted infectious agents and outlines methods of detecting and quantifying transmission.

Confirmed Bacillus anthracis infection among persons who inject drugs, Scotland, 2009-2010

Patients who died had an increased sequential organ failure assessment score and need for vasopressors.

Multiple ABC transporters are involved in the acquisition of petrobactin in Bacillus anthracis

In Bacillus anthracis the siderophore petrobactin is vital for iron acquisition and virulence. The petrobactin-binding receptor FpuA is required for these processes. Here additional components of petrobactin reacquisition are described. To identify these proteins, mutants of candidate permease and ATPase genes were generated allowing for characterization of multiple petrobactin ATP-binding cassette (ABC)-import systems. Either of two distinct permeases, FpuB or FatCD, is required for iron acquisition and play redundant roles in petrobactin transport. A mutant strain lacking both permeases, ΔfpuBΔfatCD, was incapable of using petrobactin as an iron source and exhibited attenuated virulence in a murine model of inhalational anthrax infection. ATPase mutants were generated in either of the permease mutant backgrounds to identify the ATPase(s) interacting with each individual permease channel. Mutants lacking the FpuB permease and FatE ATPase (ΔfpuBΔfatE) and a mutant lacking the distinct ATPases FpuC and FpuD generated in the ΔfatCD background (ΔfatCDΔfpuCΔfpuD) displayed phenotypic characteristics of a mutant deficient in petrobactin import. A mutant lacking all three of the identified ATPases (ΔfatEΔfpuCΔfpuD) exhibited the same growth defect in iron-depleted conditions. Taken together, these results provide the first description of the permease and ATPase proteins required for the import of petrobactin in B. anthracis.

Subcutaneous anthrax in three intravenous drug users: a new clinical diagnosis

Anthrax is extremely rare in the western world but is endemic to areas of south and central Asia. In early 2010 an outbreak was identified in heroin-injecting intravenous drug users in the United Kingdom and Europe. Afghanistan is currently the principal source of heroin which reaches the United Kingdom. When anthrax occurs, cutaneous disease accounts for over 95% of cases. At least 47 cases with 13 deaths have been confirmed so far. We present three cases presenting during this time with marked swelling, one resulting in compartment syndrome but all with an absence of the expected cutaneous appearances. We suggest that rather than cutaneous anthrax, these patients represent a new subcutaneous presentation of anthrax.

A case of septicaemic anthrax in an intravenous drug user

Background

In 2000, Ringertz et al described the first case of systemic anthrax caused by injecting heroin contaminated with anthrax. In 2008, there were 574 drug related deaths in Scotland, of which 336 were associated with heroin and or morphine. We report a rare case of septicaemic anthrax caused by injecting heroin contaminated with anthrax in Scotland.

Case Presentation

A 32 year old intravenous drug user (IVDU), presented with a 12 hour history of increasing purulent discharge from a chronic sinus in his left groin. He had a tachycardia, pyrexia, leukocytosis and an elevated C-reactive protein (CRP). He was treated with Vancomycin, Clindamycin, Ciprofloxacin, Gentamicin and Metronidazole. Blood cultures grew Bacillus anthracis within 24 hours of presentation. He had a computed tomography (CT) scan and magnetic resonance imagining (MRI) of his abdomen, pelvis and thighs performed. These showed inflammatory change relating to the iliopsoas and an area of necrosis in the adductor magnus.

He underwent an exploration of his left thigh. This revealed chronically indurated subcutaneous tissues with no evidence of a collection or necrotic muscle. Treatment with Vancomycin, Ciprofloxacin and Clindamycin continued for 14 days. Negative Pressure Wound Therapy (NPWT) device was applied utilising the Venturi™ wound sealing kit. Following 4 weeks of treatment, the wound dimensions had reduced by 77%.

Conclusions

Although systemic anthrax infection is rare, it should be considered when faced with severe cutaneous infection in IVDU patients. This case shows that patients with significant bacteraemia may present with no signs of haemodynamic compromise. Prompt recognition and treatment with high dose IV antimicrobial therapy increases the likelihood of survival. The use of simple wound therapy adjuncts such as NPWT can give excellent wound healing results.

Genetic analysis of petrobactin transport in Bacillus anthracis

Iron acquisition mechanisms play an important role in the pathogenesis of many infectious microbes. In Bacillus anthracis, the siderophore petrobactin is required for both growth in iron-depleted conditions and for full virulence of the bacterium. Here we demonstrate the roles of two putative petrobactin binding proteins FatB and FpuA (encoded by GBAA5330 and GBAA4766 respectively) in B. anthracis iron acquisition and pathogenesis. Markerless deletion mutants were created using allelic exchange. The Delta fatB strain was capable of wild-type levels of growth in iron-depleted conditions, indicating that FatB does not play an essential role in petrobactin uptake. In contrast, Delta fpuA bacteria exhibited a significant decrease in growth under low-iron conditions when compared with wild-type bacteria. This mutant could not be rescued by the addition of exogenous purified petrobactin. Further examination of this strain demonstrated increased levels of petrobactin accumulation in the culture supernatants, suggesting no defect in siderophore synthesis or export but, instead, an inability of Delta fpuA to import this siderophore. Delta fpuA spores were also significantly attenuated in a murine model of inhalational anthrax. These results provide the first genetic evidence demonstrating the role of FpuA in petrobactin uptake.

Human anthrax in Turkey from 1990 to 2007

Anthrax is an endemic disease in Turkey, among other countries of the world. The potential of Bacillus anthracis as a bioterrorism agent makes anthrax an important global issue. The aim of the present study was to review human anthrax in Turkey during the last decade. Human anthrax cases recorded from 1990 to 2005 were obtained from the website of the Turkish Ministry of Health, and those recorded between 1995 and 2005 were plotted on a map of Turkey. Papers on anthrax published from Turkey between 1990 and 2007 were collected and reviewed. Most cases were recorded from the central and eastern parts of Turkey. Three of the reports appeared in international journals prior to 1990, 10 reports appeared in the 1990s, and 24 reports appeared after the anthrax events of 2001 in the United States of America. These reports included 926 cases, 426 of which could be reviewed: 413 (96.9%) cases of cutaneous anthrax, 8 (1.9%) cases of gastrointestinal anthrax, and 5 (1.2%) cases of anthrax meningitis. Of all the affected patients, 95.2% had contact with contaminated materials. All human origin isolates were sensitive to penicillin and did not produce beta-lactamase. Most of the patients (88.7%) had received penicillin G. Total mortality was 2.8%. Anthrax is an endemic disease in Turkey, and acquisition of infection is generally through contact with ill or dying animals or animal products. Sheep and cattle are generally involved. Most clinical disease in humans is cutaneous anthrax, although other clinical forms are seen and have a greater mortality. Penicillin remains the drug of choice in treating the disease. Controlling anthrax in humans depends on controlling the infection in animals.