Efficacy Projection of Obiltoxaximab for Treatment of Inhalational Anthrax across a Range of Disease Severity.

Inhalational anthrax has high mortality even with antibiotic treatment, and antitoxins are now recommended as an adjunct to standard antimicrobial regimens. The efficacy of obiltoxaximab, a monoclonal antibody against anthrax protective antigen (PA), was examined in multiple studies conducted in two animal models of inhalational anthrax. A single intravenous bolus of 1 to 32 mg/kg of body weight obiltoxaximab or placebo was administered to New Zealand White rabbits (two studies) and cynomolgus macaques (4 studies) at disease onset (significant body temperature increase or detection of serum PA) following lethal challenge with aerosolized Bacillus anthracis spores. The primary endpoint was survival. The relationship between efficacy and disease severity, defined by pretreatment bacteremia and toxemia levels, was explored. In rabbits, single doses of 1 to 16 mg/kg obiltoxaximab led to 17 to 93% survival. In two studies, survival following 16 mg/kg obiltoxaximab was 93% and 62% compared to 0% and 0% for placebo (P = 0.0010 and P = 0.0013, respectively). Across four macaque studies, survival was 6.3% to 78.6% following 4 to 32 mg/kg obiltoxaximab. In two macaque studies, 16 mg/kg obiltoxaximab reduced toxemia and led to survival rates of 31%, 35%, and 47% versus 0%, 0%, and 6.3% with placebo (P = 0.0085, P = 0.0053, P = 0.0068). Pretreatment bacteremia and toxemia levels inversely correlated with survival. Overall, obiltoxaximab monotherapy neutralized PA and increased survival across the range of disease severity, indicating clinical benefit of toxin neutralization with obiltoxaximab in both early and late stages of inhalational anthrax.

An Aggregate of Four Anthrax Cases during the Dry Summer of 2011 in Epirus, Greece.

BACKGROUND: Human anthrax is currently a sporadic disease in Europe, without significant regional clustering. OBJECTIVE: To report an unexpected aggregate of anthrax cases and correlate local climatic factors with yearly anthrax admissions. METHODS: Clinical description of a geographical-temporal anthrax aggregate, correlation of disease admissions with local weather data in the period 2001-2014 and literature reports of anthrax clusters from Europe in the last 20 years. RESULTS: We identified 5 cases, all cutaneous: an unexpected aggregate of 4 cases in mid-summer 2011 (including a probable human-to-human transmission) and a sporadic case in August 2005, all in relatively dry periods (p < 0.05). Remarkably, 3/6 reports of human anthrax aggregates from Europe were observed in Balkan Peninsula countries in the year 2011. CONCLUSION: In the light of the predicted climatic change, unexpected anthrax aggregates during dry periods in southern Europe underscore the risk of future anthrax re-emergence on this continent.

Injectional anthrax at a Scottish district general hospital.

This retrospective, descriptive case-series reviews the clinical presentations and significant laboratory findings of patients diagnosed with and treated for injectional anthrax (IA) since December 2009 at Monklands Hospital in Central Scotland and represents the largest series of IA cases to be described from a single location. Twenty-one patients who fulfilled National Anthrax Control Team standardized case definitions of confirmed, probable or possible IA are reported. All cases survived and none required limb amputation in contrast to an overall mortality of 28% being experienced for this condition in Scotland. We document the spectrum of presentations of soft tissue infection ranging from mild cases which were managed predominantly with oral antibiotics to severe cases with significant oedema, organ failure and coagulopathy. We describe the surgical management, intensive care management and antibiotic management including the first description of daptomycin being used to treat human anthrax. It is noted that some people who had injected heroin infected with Bacillus anthracis did not develop evidence of IA. Also highlighted are biochemical and haematological parameters which proved useful in identifying deteriorating patients who required greater levels of support and surgical debridement.

Injectional anthrax - new presentation of an old disease.

Bacillus anthracis infection (anthrax) has three distinct clinical presentations depending on the route of exposure: cutaneous, gastrointestinal and inhalational anthrax. Each of these can lead to secondary bacteraemia and anthrax meningitis. Since 2009,anthrax has emerged among heroin users in Europe,presenting a novel clinical manifestation, 'injectional anthrax', which has been attributed to contaminated heroin distributed throughout Europe; before 2009 only one case was reported. During 2012 and 2013,new cases of injectional anthrax were diagnosed in Denmark, France, Germany, and the United Kingdom.Here we present a comprehensive review of the literature and information derived from different reporting systems until 31 December 2013. Overall 70 confirmed cases were reported, with 26 fatalities (37% case fatality rate).The latest two confirmed cases occurred in March 2013. Thirteen case reports have been published,describing 18 confirmed cases. Sixteen of these presented as a severe soft tissue infection that differed clinically from cutaneous anthrax, lacked the characteristic epidemiological history of animal contact and ten cases required complimentary surgical debridement. These unfamiliar characteristics have led to delays of three to 12 days in diagnosis, inadequate treatment and a high fatality rate. Clinicians' awareness of this recently described clinical entity is key for early 'and successful management of patients.

Cutaneous anthrax in a school teacher.

Cutaneous anthrax is an infection of the skin caused by Bacillus anthracis. This is a report of a case of cutaneous anthrax attending outpatients of Mymensingh Medical College Hospital in October, 2010. The infected person was a retired school teacher with a very good body build. He reported to handle cow flesh about 4-5 days ago, developed few painless papules over shin of right leg, which gradually became large bullae and blackish eschar developed over the lesion. Smears from the lesions were investigated which confirmed the causative agent B. anthracis. The patient was treated with oral Ciprofloxacin (500mg) twice daily for seven days which cured the infection as observed on his subsequent follow up visits on 7 and 14 days later. Oral Ciprofloxacin is found effective as recommended by the World Health Organization.

Anthrax: a case report.

Anthrax is a zoonotic disease caused by a bacterium called Bacillus Anthracis. In humans, it causes a cutaneous, gastro-intestinal and inhalation form of disease. The in-cutaneous form progresses along with skin necrosis and oedema. Since the necroses in the skin are not quite superficial, they can affect the tendon sheaths progressing close to the skin. Therefore, in surgical treatment, the closure in the areas where tendons are surfaced must be provided by a flap instead of a graft.The repair on the existing patient was performed with a graft since the flap repair was not accepted, and thus, restrictions in hand movements occurred during the post-operative period.

CodY regulation is required for full virulence and heme iron acquisition in Bacillus anthracis.

Capsule and toxin are the major virulence factors of Bacillus anthracis. The B. anthracis pleiotropic regulator CodY activates toxin gene expression by post-translationally regulating the accumulation of the global regulator AtxA. However, the role of CodY on B. anthracis capsulation and virulence of encapsulated strains has been unknown. The role of CodY in B. anthracis virulence was studied in mouse and guinea pig models. Spore outgrowth and dissemination of the vegetative cells was followed in mice by bioluminescent imaging. We also determined the state of capsulation and the iron requirement for growth of the codY mutant. In all models tested, the codY mutant strain was strongly attenuated compared to the wild-type strain and, in mice, also compared to the atxA strain. The disruption of codY did not affect either ex vivo or in vivo capsulation, whereas atxA deletion affected ex vivo capsulation only. The disruption of codY led to a delayed initiation of dissemination but similar kinetics of subsequent spread of the bacilli. The codY mutant cannot grow on heme iron as sole iron source, whereas the parental and complemented strains can. The lack of CodY-mediated transcription weakens virulence by controlling iron acquisition and synthesis of toxin, but without modifying capsulation.

A decade of spore-forming bacterial infections among European injecting drug users: pronounced regional variation.

The recent anthrax outbreak among injecting drug users (IDUs) in Europe has highlighted an ongoing problem with severe illness resulting from spore-forming bacteria in IDUs. We collated the numbers of cases of 4 bacterial illnesses (botulism, tetanus, Clostridium novyi, and anthrax) in European IDUs for 2000 to 2009 and calculated population rates. Six countries reported 367 cases; rates varied from 0.03 to 7.54 per million people. Most cases (92%) were reported from 3 neighboring countries: Ireland, Norway, and the United Kingdom. This geographic variation needs investigation.

Anthrax infection.

Bacillus anthracis infection is rare in developed countries. However, recent outbreaks in the United States and Europe and the potential use of the bacteria for bioterrorism have focused interest on it. Furthermore, although anthrax was known to typically occur as one of three syndromes related to entry site of (i.e., cutaneous, gastrointestinal, or inhalational), a fourth syndrome including severe soft tissue infection in injectional drug users is emerging. Although shock has been described with cutaneous anthrax, it appears much more common with gastrointestinal, inhalational (5 of 11 patients in the 2001 outbreak in the United States), and injectional anthrax. Based in part on case series, the estimated mortalities of cutaneous, gastrointestinal, inhalational, and injectional anthrax are 1%, 25 to 60%, 46%, and 33%, respectively. Nonspecific early symptomatology makes initial identification of anthrax cases difficult. Clues to anthrax infection include history of exposure to herbivore animal products, heroin use, or clustering of patients with similar respiratory symptoms concerning for a bioterrorist event. Once anthrax is suspected, the diagnosis can usually be made with Gram stain and culture from blood or surgical specimens followed by confirmatory testing (e.g., PCR or immunohistochemistry). Although antibiotic therapy (largely quinolone-based) is the mainstay of anthrax treatment, the use of adjunctive therapies such as anthrax toxin antagonists is a consideration.

Benchmark dose analysis for Bacillus anthracis inhalation exposures in the nonhuman primate.

There is considerable variability in the published lethality values for inhalation exposures of Bacillus anthracis. The lack of consensus on an acceptable dose-response relationship poses a significant challenge in the development of risk-based management approaches for use following a terrorist release of B. anthracis spores. This article reviewed available B. anthracis dose-response modeling and literature for the nonhuman primate, evaluated the use of the U.S. Environmental Protection Agency's Benchmark Dose Software (BMDS) to fit mathematical dose-response models to these data, and reported results of the benchmark dose analysis of suitable data sets. The BMDS was found to be a useful tool to evaluate dose-response relationships in microbial data, including that from B. anthracis exposure. An evaluation of the sources of variability identified in the published lethality data and the corresponding BMDS-derived lethality values found that varying levels of physical characterization of the spore product, differing receptor-specific exposure assumptions, choice of dose metrics, and the selected statistical methods all contributed to differences in lethality estimates. Recognition of these contributors to variability could ultimately facilitate agreement on a B. anthracis dose-response relationship through provision of a common description of necessary study considerations for acceptable dose-response data sets.

Fatal anthrax infection in a heroin user from southern Germany, June 2012.

Blood cultures from a heroin user who died in June 2012, a few hours after hospital admission, due to acute septic disease, revealed the presence of Bacillus anthracis. This report describes the extended diagnosis by MALDI-TOF and real-time PCR and rapid confirmation of the anthrax infection through reference laboratories. Physicians and diagnostic laboratories were informed and alerted efficiently through the reporting channels of German public health institutions, which is essential for the prevention of further cases.

Secondary cell wall polysaccharides from Bacillus cereus strains G9241, 03BB87 and 03BB102 causing fatal pneumonia share similar glycosyl structures with the polysaccharides from Bacillus anthracis.

Secondary cell wall polysaccharides (SCWPs) are important structural components of the Bacillus cell wall and contribute to the array of antigens presented by these organisms in both spore and vegetative forms. We previously found that antisera raised to Bacillus anthracis spore preparations cross-reacted with SCWPs isolated from several strains of pathogenic B. cereus, but did not react with other phylogenetically related but nonpathogenic Bacilli, suggesting that the SCWP from B. anthracis and pathogenic B. cereus strains share specific structural features. In this study, SCWPs from three strains of B. cereus causing severe or fatal pneumonia (G9241, 03BB87 and 03BB102) were isolated and subjected to structural analysis and their structures were compared to SCWPs from B. anthracis. Complete structural analysis was performed for the B. cereus G9241 SCWP using NMR spectroscopy, mass spectrometry and derivatization methods. The analyses show that SCWPs from B. cereus G9241 has a glycosyl backbone identical to that of B. anthracis SCWP, consisting of multiple trisaccharide repeats of: →6)-α-d-GlcpNAc-(1 â†’ 4)-ß-d-ManpNAc-(1 â†’ 4)-ß-d-GlcpNAc-(1→. Both the B. anthracis and pathogenic B. cereus SCWPs are highly substituted at all GlcNAc residues with α- and ß-Gal residues, however, only the SCWPs from B. cereus G9241 and 03BB87 carry an additional α-Gal substitution at O-3 of ManNAc residues, a feature lacking in the B. anthracis SCWPs. Both the B. anthracis and B. cereus SCWPs are pyruvylated, with an approximate molecular mass of ≈12,000 Da. The implications of these findings regarding pathogenicity and cell wall structure are discussed.

Delayed treatment with W1-mAb, a chimpanzee-derived monoclonal antibody against protective antigen, reduces mortality from challenges with anthrax edema or lethal toxin in rats and with anthrax spores in mice.

OBJECTIVE: W1-mAb is a chimpanzee-derived monoclonal antibody to protective antigen that improved survival when administered before anthrax lethal toxin challenge in rats. To better define W1-mAb's efficacy for anthrax, we administered it after initiation of 24-hr infusions of edema toxin and lethal toxin either alone or together in rats or following anthrax spore challenge in mice. INTERVENTIONS: W1-mAb or placebo treatment. METHODS AND MAIN RESULTS: In toxin-challenged rats treated with placebo, survival rates were lower with edema toxin (500 µg/kg) compared to lethal toxin either alone (175 µg/kg) or with edema toxin (175 µg/kg each) (8%, 33%, and 32%, respectively), but the median time to death was longer (36, 11, and 9 hrs, respectively) (p ≤ .01 for all comparisons). W1-mAb administered up to 12 hrs after edema toxin and 6 hrs after lethal toxin increased survival and reduced hypotension (p ≤ .01). However, only administration of W1-mAb at 0 hrs improved these variables with lethal toxin and edema toxin together (p ≤ .0002). In C57BL/6J mice challenged with anthrax spores subcutaneously, compared to placebo treatment (0 of 15 animals survived), W1-mAb administered beginning 24 hrs after challenge increased survival (13 of 15 survived) (p ≤ .0001). CONCLUSION: While rapidity of lethality may influence the effectiveness of delayed W1-mAb treatment, these rat and mouse studies provide a basis for further exploring this agent's usefulness for 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.

[Landscape components favouring the occurrence of anthrax in the Flooding Pampa grasslands (Buenos Aires province, Argentina)]. / Componentes del paisaje que favorecen la aparición de carbunco en la Pampa Deprimida (provincia de Buenos Aires, Argentina).

The authors studied the landscape components that favour the occurrence of anthrax in the Flooding Pampa grasslands (Buenos Aires province, Argentina). They made spatial locations of anthrax outbreaks diagnosed by registered veterinary laboratories in the study area's zone of influence. As variables for study, they differentiated areas that are flooded for 20% of the time or more from primary and secondary runoff channels. They also identified areas with low-productivity pasture. Logistic regression analysis of farm populations revealed that landscape components favouring the occurrence of anthrax outbreaks are shared runoff channels (odds ratio (OR) = 2.3; confidence interval (CI) = 1.2; 4.7) and > or = 40% low-productivity pasture (OR = 5.4; CI = 3.5; 8.3). Contrary to initial assumptions, susceptibility to flooding was not a significant variable (OR = 1.1; CI = 0.5; 2.1). The authors concluded that the first step in decision-making and ensuring more efficient implementation of future anthrax control and eradication plans was to identify risk variables.

Risk factors and spatio-temporal patterns of livestock anthrax in Khuvsgul Province, Mongolia.

Anthrax is a worldwide zoonotic disease. Anthrax has long been a public health and socio-economic issue in Mongolia. Presently, there is no spatial information on carcass burial sites as a potential hazard of future anthrax outbreaks and possible risk factors associated with anthrax occurrences in Mongolia. Here, we analyze retrospective data (1986-2015) on the disposal sites of livestock carcasses to describe historical spatio-temporal patterns of livestock anthrax in Khuvsgul Province, which showed the highest anthrax incidence rate in Mongolia. From the results of spatial mean and standard deviational ellipse analyses, we found that the anthrax spatial distribution in livestock did not change over the study period, indicating a localized source of exposure. The multi-distance spatial cluster analysis showed that carcass sites distributed in the study area are clustered. Using kernel density estimation analysis on carcass sites, we identified two anthrax hotspots in low-lying areas around the south and north regions. Notably, this study disclosed a new hotspot in the northern part that emerged in the last decade of the 30-year study period. The highest proportion of cases was recorded in cattle, whose prevalence per area was highest in six districts (i.e., Murun, Chandmani-Undur, Khatgal, Ikh-Uul, Tosontsengel, and Tsagaan-Uul), suggesting that vaccination should prioritize cattle in these districts. Furthermore, size of outbreaks was influenced by the annual summer mean air temperature of Khuvsgul Province, probably by affecting the permafrost freeze-thawing activity.

The bicarbonate transporter is essential for Bacillus anthracis lethality.

In the pathogenic bacterium Bacillus anthracis, virulence requires induced expression of the anthrax toxin and capsule genes. Elevated CO2/bicarbonate levels, an indicator of the host environment, provide a signal ex vivo to increase expression of virulence factors, but the mechanism underlying induction and its relevance in vivo are unknown. We identified a previously uncharacterized ABC transporter (BAS2714-12) similar to bicarbonate transporters in photosynthetic cyanobacteria, which is essential to the bicarbonate induction of virulence gene expression. Deletion of the genes for the transporter abolished induction of toxin gene expression and strongly decreased the rate of bicarbonate uptake ex vivo, demonstrating that the BAS2714-12 locus encodes a bicarbonate ABC transporter. The bicarbonate transporter deletion strain was avirulent in the A/J mouse model of infection. Carbonic anhydrase inhibitors, which prevent the interconversion of CO2 and bicarbonate, significantly affected toxin expression only in the absence of bicarbonate or the bicarbonate transporter, suggesting that carbonic anhydrase activity is not essential to virulence factor induction and that bicarbonate, and not CO2, is the signal essential for virulence induction. The identification of this novel bicarbonate transporter essential to virulence of B. anthracis may be of relevance to other pathogens, such as Streptococcus pyogenes, Escherichia coli, Borrelia burgdorferi, and Vibrio cholera that regulate virulence factor expression in response to CO2/bicarbonate, and suggests it may be a target for antibacterial intervention.

Gastrointestinal anthrax after an animal-hide drumming event - New Hampshire and Massachusetts, 2009.

On December 24, 2009, a woman aged 24 years from New Hampshire was confirmed to have gastrointestinal anthrax on the basis of clinical findings and a Bacillus anthracis blood culture isolate. Her symptoms began on December 5. One day before symptom onset, she had participated in a drumming event at a community organization's building where animal-hide drums of multiple ages and origins were played. This report describes the case and subsequent investigation, which identified 84 persons potentially exposed to anthrax, including those persons at the drumming event and those who lived or worked at the event site. Review of New Hampshire disease surveillance data and clinical microbiology records for periods before and after the event identified no additional anthrax cases. Initial qualitative environmental testing of the event site yielded three positive samples (two from drum heads and one composite sample of three electrical outlets in the main drumming room). Wider, targeted, semi-quantitative environmental testing of the site and additional drums yielded six positive samples (two from one drum and four from environmental locations in the building). These results suggested that aerosolization of spores from drumheads had occurred. All isolates obtained from environmental and drum samples matched the patient's isolate by multiple-locus variable-number tandem repeat analysis using eight loci (MLVA-8). Public health agencies and persons with exposure to animal-hide drums should be aware of the potential, although remote, risk for anthrax exposure associated with these drums.

Preliminary case report of fatal anthrax in an injecting drug user in North-Rhine-Westphalia, Germany, December 2009.

A fatal case of anthrax occurred in an injecting drug user in Germany, in December 2009. A potential link to similar cases in Scotland in the same time period is currently under investigation.

An outbreak of infection with Bacillus anthracis in injecting drug users in Scotland.

An investigation is currently underway to explore and control an outbreak of Bacillus anthracis among drug users (mainly injecting) in Scotland. Contaminated heroin or a contaminated cutting agent mixed with the heroin is considered to be the most likely source and vehicle of infection. Heroin users have been advised of the risk. The risk to the general public is regarded as very low.