Soft tissue infections caused by marine bacterial pathogens: epidemiology, diagnosis, and management

Mycobacterium marinum: A Case-Based Narrative Review of Diagnosis and Management

Skin and soft tissue infections caused by non-tuberculous mycobacteria are occurring more frequently in recent years. However, chronic skin and soft tissue lesions present a challenge for clinicians, as the diagnostic work-up and definitive diagnosis require knowledge and available laboratory resources. We present here the case of a 66-year-old male patient who presented with painful abscess-like nodules on his right hand and forearm, which worsened after treatment with an anti-TNF-a agent. The fluid specimen taken from the lesion was positive for mycobacteria according to the acid-fast stain. Mycobacterium marinum was identified, first by next-generation sequencing and finally grown on culture, after eight weeks. Acknowledging the complexity of diagnosing and managing infections by non-tuberculous mycobacteria, and especially Mycobacterium marinum, we provide a review of the current epidemiology, clinical characteristics, diagnosis and management of Mycobacterium marinum infection.

Anti-Vibrio potential of natural products from marine microorganisms

The emergence of drug-resistant Vibrio poses a serious threat to aquaculture and human health, thus there is an urgent need for the discovery of new related antibiotics. Given that marine microorganisms (MMs) are evidenced as important sources of antibacterial natural products (NPs), great attention has been gained to the exploration of potential anti-Vibrio agents from MMs. This review summarizes the occurrence, structural diversity, and biological activities of 214 anti-Vibrio NPs isolated from MMs (from 1999 to July 2022), including 108 new compounds. They were predominantly originated from marine fungi (63%) and bacteria (30%) with great structural diversity, including polyketides, nitrogenous compounds, terpenoids, and steroids, among which polyketides account for nearly half (51%) of them. This review will shed light on the development of MMs derived NPs as potential anti-Vibrio lead compounds with promising applications in agriculture and human health.

Characterization of Prophylactic Antimicrobial Therapy Practices for Patients With Marine-Associated Injuries in the Emergency Department

BACKGROUND

Centers for Disease Control and Prevention (CDC) recommendations for the treatment of marine-associated wound infections include empiric coverage for Vibrio species with a combination of a third-generation cephalosporin and doxycycline. These recommendations are based on limited data and it remains unclear if this regimen is also indicated for prophylaxis.

OBJECTIVE

The purpose of this analysis was to assess the antibiotic regimens used in the emergency department (ED) for prophylaxis of marine-associated injuries relative to the CDC recommendations and evaluate any clinical impact.

METHODS

A retrospective review evaluated adult patients discharged from the ED over a 4-year period with an antibiotic prescription following an injury with marine exposure.

RESULTS

114 patients were included in the analysis. The majority of patients were < 40 years of age with no previous medical history and presented after sustaining a laceration secondary to oyster shells. 97.4% received prophylactic antibiotic therapy that did not match the CDC recommendations, with the majority receiving doxycycline monotherapy (82%). A 1.8% 30-day ED revisit rate was noted with 2 patients returning for therapy failure. No patients were admitted to the hospital within 30 days and no documented adverse effects related to antibiotic therapy were noted.

CONCLUSION

Current prophylactic antibiotic prescribing practices diverge from the current CDC recommendations for the treatment of marine-associated infections, however, an effect secondary to these variations was not observed. Further investigations of prophylaxis against Vibrio infections in low-risk patients is warranted to limit collateral damage and improve antimicrobial stewardship in the ED.

Severe skin and soft tissue infection in the left upper limb caused by Aeromonas veronii: a case report

INTRODUCTION

Skin and soft tissue infections are common because of exposure to aquatic environment, while severe infections caused by Aeromonas veronii are rare.

CASE PRESENTATION

We report a case of severe skin and soft tissue infection of the left upper limb caused by Aeromonas veronii. A 50-year-old Chinese woman, who had a history of cardiac disease and type 2 diabetes mellitus, accidentally injured her left thumb while cutting a fish. Early antibiotic therapy and surgical debridement was performed before the result of bacterial culture came back. Whole-genome sequencing was further performed to confirm the pathogen and reveal the drug resistance and virulence genes. The wound was gradually repaired after 1 month of treatment, and the left hand recovered well in appearance and function after 3 months of rehabilitation.

CONCLUSION

Early diagnosis, surgical intervention, and administration of appropriate antibiotics are crucial for patients who are suspected of having skin and soft tissue infection, or septicemia caused by Aeromonas veronii.

Natural products as antivibrio agents: insight into the chemistry and biological activity

Vibriosis causes serious problems and economic loss in aquaculture and human health. Investigating natural products as antivibrio agents has gained more attention to combat vibriosis. The present review highlights the chemical diversity of antivibrio isolated from bacteria, fungi, plants, and marine organisms. Based on the study covering the literature from 1985-2021, the chemical diversity ranges from alkaloids, terpenoids, polyketides, sterols, and peptides. The mechanisms of action are included inhibiting growth, interfering with biofilm formation, and disrupting of quorum sensing. Relevant summaries focusing on the source organisms and the associated bioactivity of different chemical classes are also provided. Further research on in vivo studies, toxicity, and clinical is required for the application in aquaculture and human health.

Emerging Infections Due to Shewanella spp.: A Case Series of 128 Cases Over 10 Years

Background

Shewanella species are emerging pathogens that can cause severe hepatobiliary, skin and soft tissue, gastrointestinal, respiratory infections, and bacteremia. Here we reported the largest case series of infections caused by Shewanella species.

Aim

To identify the clinical features and risk factors predisposing to Shewanella infections. To evaluate resistance pattern of Shewanella species and appropriateness of antibiotic use in the study cohort.

Methods

Patients admitted to a regional hospital in Hong Kong with Shewanella species infection from April 1, 2010 to December 31, 2020 were included. Demographics, antibiotics, microbiology, and outcomes were retrospectively analyzed.

Findings

Over the 10 years, we identified 128 patients with Shewanella species infection. 61.7% were male with a median age of 78 (IQR 65–87). Important underlying diseases included hepatobiliary diseases (63.3%), malignancy (26.6%), chronic kidney disease or end-stage renal failure (25.8%), and diabetes mellitus (22.7%). Hepatobiliary infections (60.4%) were the most common clinical manifestation. Majority (92.2%) were infected with Shewanella algae, while 7.8% were infected with Shewanella putrefaciens. The identified organisms were usually susceptible to ceftazidime (98.7%), gentamicin (97.4%), cefoperazone-sulbactam (93.5%) and ciprofloxacin (90.3%). Imipenem-susceptible strains were only present in 76.6% of isolates.

Conclusion

This largest case series suggested that Shewanella infections are commonly associated with underlying comorbidities, especially with hepatobiliary diseases and malignancy. Although Shewanella species remained largely susceptible to third and fourth generation cephalosporins and aminoglycosides, carbapenem resistance has been on a significant rise.

Infections following stingray attacks: A case series and literature review of antimicrobial resistance and treatment

BACKGROUND

Injuries sustained following stingray attacks are at high risk of infection and can progress to serious, debilitating consequences for the patient if not appropriately addressed. Antibiotic treatment of such infections is important to minimise the morbidity experienced by patients. However, antibiotic guidelines relating specific to this patient group are not well established. This study aims to report the experience of a single institution at treating stingray associated wound infections and to review the literature for reported cases. Additionally, we review the microbiological risk in these patients and summarise the literature surrounding antibiotic choice.

METHODS

A retrospective review of all patients presenting with injuries sustained following stingray attacks was conducted at a single institution. Additionally, a comprehensive literature review was conducted to identify cases of infected stingray associated trauma and review the causative micro-organisms and antibiotics used to treat such infections.

RESULTS

22 cases of stingray injuries were identified from a single institution. Of these, eight infections were reported. One case grew a highly resistant Vibrio species. Among the literature, 18 cases of infections were identified many of which led to significant complications for patients. The micro-organisms identified were diverse and there was little consistency among the antibiotic regimens utilised.

CONCLUSION

Based on the antibiotic susceptibilities of causative bacteria along with extrapolation from recommendations and guidelines identified in the literature, ciprofloxacin, doxycycline and trimethoprim-sulfamethoxazole appear to be the most appropriate antibiotics choices for prophylaxis or treatment of localised infection. Antibiotic choices for the empiric treatment of systemic infection requires further research and clarification.

Cellulitis: A Review of Current Practice Guidelines and Differentiation from Pseudocellulitis

Cellulitis, an infection involving the deep dermis and subcutaneous tissue, is the most common reason for skin-related hospitalization and is seen by clinicians across various disciplines in the inpatient, outpatient, and emergency room settings, but it can present as a diagnostic and therapeutic challenge. Cellulitis is a clinical diagnosis based on the history of present illness and physical examination and lacks a gold standard for diagnosis. Clinical presentation with acute onset of redness, warmth, swelling, and tenderness and pain is typical. However, cellulitis can be difficult to diagnose due to a number of infectious and non-infectious clinical mimickers such as venous stasis dermatitis, contact dermatitis, eczema, lymphedema, and erythema migrans. Microbiological diagnosis is often unobtainable due to poor sensitivity of culture specimens. The majority of non-purulent, uncomplicated cases of cellulitis are caused by β-hemolytic streptococci or methicillin-sensitive Staphylococcus aureus, and appropriate targeted coverage of this pathogen with oral antibiotics such as penicillin, amoxicillin, and cephalexin is sufficient. Even with rising rates of community-acquired methicillin-resistant Staphylococcus aureus, coverage for non-purulent cellulitis is generally not recommended.

Assessment of seawater bacterial infection in rabbit tibia by Illumina MiSeq sequencing and bacterial culture

Objectives

We aimed to explore the bacterial community composition following ocean bacterial infection using an animal model.

Methods

This animal-based experiment was conducted from September 2019 to November 2019. Eighteen seawater filter membranes were collected from Changle City, Fujiian Province, China, on September 8, 2019. Ten filter membranes were used for implantation. Eight filter membranes that were used in the bacterial culture for the exploration of seawater bacteria were assigned to the seawater group (SG). Fourteen healthy adult New Zealand rabbits were randomly divided into the experimental group (EG) and control group (CG). Seawater filter membranes and asepsis membranes were implanted into the tibia in the EG and CG, respectively. One week after surgery, tibial bone pathology tissues were collected and assessed using light microscopy and scanning electron microscopy (SEM). Medullary cavity tissues were collected for the performance of Illumina MiSeq sequencing and bacterial culture. The differences between EG and CG were assessed by pathological observation under light microscopy and SEM, high-throughput bacterial sequencing, and bacterial culture.

Results

Compared with the CG, the infection rate was 100%, and the mortality value was 20% after the implantation of the filter membranes in the EG. Both light microscopy and SEM showed that a large number of bacteria were distributed in the bone marrow cavity after ocean bacterial infection. No bacterial growth was found in the CG. Illumina MiSeq sequencing found that Firmicutes, Proteobacteria, Thermotogae, Fusobacteria, Bacteroidetes, and Actinobacteria were the dominant bacteria at the phylum level and Clostridium_sensu_stricto_7, Haloimpatiens, Clostridium_sensu_stricto_15, Clostridiaceae_1, Clostridium_sensu_stricto_18, and Oceanotoga were the dominant bacteria in genus level among the EG. In the bacterial culture of the medullary cavity tissues, Klebsiella pneumoniae, Shewanella algae, Staphylococcus aureus, Escherichia coli, Enterobacter cloacae, and Vibrio vulnificus were the predominant infective species. Moreover, compared with the SG, the EG showed a higher detection rate of E. coli and S. aureus (P = 0.008 and P = 0.001, respectively). The detection rates of V. alginolyticus, V. parahaemolyticus, and V. fluvialis were higher in the SG than the EG (P = 0.007, P = 0.03, and P = 0.03, respectively).

Conclusions

Our model, which was comprehensively evaluated using four techniques: histopathology and SEM observation, gene detection, and bacteria culture, provides a scientific basis for the clinical diagnosis and treatment of patients in such settings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02553-9.

Aeromonas hydrophila Survives the Treatment of Posttraumatic Cellulitis in the Shelter of an Obscured Fish-Bone Fragment

Fish bone and/or spine puncture injuries can result in infection of the upper extremities with aquatic bacterial pathogens. Additionally, in such injuries, the inoculation of foreign organic material is frequent and may further complicate the clinical presentation and course of the resulting infection. We describe the case of a 45-year-old female patient with a minimal fish rostrum puncture trauma acquired during preparation of fresh fish meal, which resulted in a galloping hand cellulitis. The alarming clinical presentation and the prompt response of the skin infection to clindamycin obscured the presence of inoculated fish rostrum remnants in the tissue that, three weeks later, gave rise to a foreign body granuloma, from which Aeromonas hydrophila was isolated. Final resolution was achieved with an additional two-week doxycycline treatment. In conclusion, the reported case highlights the potential of the accidentally implanted organic material, as are fish bones, not only to transfer uncommon pathogens but also to offer a sanctuary that favors microbial survival despite antibiotic therapy thus enabling latent or recurrent infections.

Rapidly Progressive Soft Tissue Infection of the Upper Extremity With Aeromonas veronii Biovar sobria

Aeromonas veronii, a bacterium found in freshwater, is an unusual pathogen in healthy patients. We present a case report of a rare, aggressive subtype in a young, immunocompetent individual. History of injury in an aquatic environment and culture data are key for identification of the causal agent and should dictate acute clinical management and antibiotic therapy. Coverage should include cephalosporins, quinolones, or sulfas if Aeromonas is suspected, and adjusted depending on culture and sensitivity. Early surgical exploration, incision and drainage, and appropriate antimicrobial therapy are the cornerstones for successful treatment of these aggressive, sometimes life-threatening infections.

Infecção marinha

Introdução: Cidades litorâneas possuem atividades econômicas como a pesca e o turismo que promovem o contato com a água do mar e, consequentemente, a exposição a microrganismos raramente encontrados em outros contextos e muitas vezes de diagnóstico tardio, podendo resultar em morbidade ou morte significativa. Objetivo: Essa revisão da literatura objetiva mostrar a importância da suspeição da infecção marinha na Atenção Primária, sua etiologia, manifestações clínicas, tratamento, complicações e prevenção. Métodos: Foi realizada pesquisa em bases de dados eletrônicos (SciELO, Google Acadêmico, MEDLINE e PubMed). Resultados: Foram encontrados 135 artigos e vinte foram selecionados, referentes aos anos de 2003 a 2018. Observou-se escassez de estudos que avaliam a efetividade de esquemas de antibioticoterapia e sua duração necessária. Além disso, verificou-se a ausência de classificação no Código Internacional de Doenças (CID-10) e Descritores em Ciências da Saúde (DeCS), fato que prejudica a notificação e estudos epidemiológicos sobre o assunto. Conclusão: É preciso incluir a infecção marinha no diagnóstico diferencial de casos de ferimentos crônicos de difícil diagnóstico, principalmente se houver histórico de exposição a ambiente marinho. Novos estudos se fazem necessários para avaliação da terapêutica adequada. Outrossim, é fundamental conscientizar a população quanto ao risco de infecção marinha e seus métodos de prevenção.

Does the timing of postoperative showering impact infection rates? A systematic review and meta-analysis

INTRODUCTION

Optimum timing of postoperative showering varies. Earlier showering improves patient satisfaction, but the impact of the timing of showering on postoperative infection is unclear. We conducted a systematic literature review and meta-analysis to investigate the outcomes of various postoperative showering practices.

METHODS

We searched PubMed to identify relevant human clinical studies in English, and searched these for additional references. Articles were reviewed for patient demographics, surgical specialty and procedure, wound closure method, placement of drains, showering protocol, and rates of infection and complications. Only randomized controlled trials were analyzed. A random-effects meta-analysis model was used to determine overall infection and complication rates between patients allowed to shower within the first 48 h postoperatively or later.

RESULTS

Out of 357 studies, seven and five were included in the infection and complications rate meta-analyses, respectively. A total of 1,881 and 958 patients were included in each analysis; 605 and 477 patients in each analysis were allowed to shower on or before postoperative day 2 ("early"), while the remainder were prohibited from showering until postoperative day 3 to beyond one week ("delayed") postoperatively. There was no difference in infection (p = 0.45, [-0.0052, 2 × 0.007 95% CI]) or complication rate (p = 0.36, [-0.0046, 2 × 0.005 95% CI]) with earlier vs. delayed showering protocols.

CONCLUSION

Published literature demonstrates no increase in the overall rate of wound infections or complications when patients showered earlier in the postoperative period. Additional randomized studies are needed to determine the ideal time for postoperative showering. These data should be considered by surgeons while determining when to permit patients to shower after surgery.

A rare case of Shewanella septicemia: risk factors, environmental associations and management

Shewanella species are Gram-negative, saprophytic, motile bacilli. Exposure to aquatic environment and raw fish ingestion have been defined as significant associated risk factors. The two species most commonly associated with human infections are Shewanella algae and Shewanella putrefaciens and major portion of infections (80%) caused by the former. Herein, we report a case of Shewanella septicaemia in a 70-year-old man in Omaha, NE who had no exposure to aquatic environment. To date, no defined treatment guidelines are present due to rarity of Shewanella infections, which is contributing to emerging antibiotic resistance.

Severe Sepsis and Wet Gangrene Requiring Foot Amputation Caused by an Emerging Human Pathogen - Shewanella algae

A 69-year-old woman with type 2 diabetes mellitus, peripheral vascular disease, and other comorbidities presented with recurrent syncopal episodes. Cellulitic skin changes in her right lower extremity were noted, as well as a large hemorrhagic bulla on the dorsum of her right foot. Severe sepsis was determined to be the reason for her syncopal episodes. Blood cultures and the bulla aspirate culture were positive for Shewanella algae that was pan-sensitive to antibiotics. Her clinical status was stabilized with a regimen of intravenous fluids and broad-spectrum antibiotics. However, due to the development of right foot gangrene, she underwent debridement and eventually required transmetatarsal open amputation.

Aquatic Orthopaedic Injuries

Extremity injuries sustained in aquatic environments require unique considerations compared with injuries sustained on land. Knowledge of these considerations is becoming more important as aquatic recreational activities increase in popularity. Aquatic injuries may occur through mechanical contact with a variety of different objects or surfaces, such as a recreational device or watercraft part, or may occur through contact with marine animals. Marine animal injuries can be further categorized into bites, stings, or blunt contact, as well as venomous or nonvenomous, distinctions that should be used to guide clinical management. Numerous instances of retained foreign bodies after marine animal stings exist, which can result in infection and prolonged envenomization; thus, radiographic examination should be routinely performed in aquatic sting injuries to prevent these harmful sequelae. Any aquatic injury resulting in an open wound has an increased risk for infection, and prophylactic antibiotics must be given with consideration for the unique microbiologic flora of the aquatic environment.

Mandibular osteomyelitis in the bottlenose dolphin Tursiops truncatus (Montagu, 1821) (Odontoceti: Cetacea): first case in the Mexican Caribbean

Oral pathological conditions are common in mammals and have been relatively well documented for some wild groups, but are rarely reported in marine mammals. Here, we report for the Mexican Caribbean the first case of mandibular osteomyelitis in a free-ranging dolphin. A bottlenose dolphin Tursiops truncatus adult male (256.5 cm total length) was found stranded dead in the west coast of the State Reserve “Chetumal Bay Manatee Sanctuary”. Herein, we discuss some plausible explanations about the origin of this lesion to improve the knowledge about the species biology.

Near-Complete Traumatic Amputation of the Forefoot After Motorboat Propeller Injury

We report a case of a near-complete amputation of the forefoot of a 20-year-old man as a result of a motorboat propeller injury sustained in a saltwater river. He was treated with open reduction, percutaneous pinning, extensor tendon repair, and an extended course of antibiotic prophylaxis. We review the literature regarding motorboat propeller injuries to the foot and ankle.

Swimming with the Pigs: A Case of Severe Soft Tissue Infection during a Caribbean Vacation

A 74-year-old man presented to the emergency department with severe right leg cellulitis following a trip to the Bahamas where he swam in both chlorinated pools and the ocean. His blood cultures grew Shewanella species, a marine pathogen known to cause disease in humans, following exposure to seawater. He was treated with cefepime for a total of two weeks without needing any surgical intervention. The patient had complete resolution of infection and was able to return to his activities of daily living.

The Pathogenicity of Shewanella algae and Ability to Tolerate a Wide Range of Temperatures and Salinities

Shewanella algae is a rod-shaped Gram-negative marine bacterium frequently found in nonhuman sources such as aquatic ecosystems and has been shown to be the pathogenic agent in various clinical cases due to the ingestion of raw seafood. The results of this study showed that S. algae was present in approximately one in four samples, including water and shellfish samples. Positive reactions (API systems) in S. algae strains were seen for gelatinase (gelatin); however, negative reactions were found for indole production (tryptophan). S. algae is adapted to a wide range of temperatures (4°C, 25°C, 37°C, and 42°C) and salinity. Temperature is a key parameter in the pathogenicity of S. algae as it appears to induce hemolysis at 25°C and 37°C. S. algae exhibits pathogenic characteristics at widely varying temperatures, which suggests that it may have the ability to adapt to climate change.

Epidemiology of fishing related upper extremity injuries presenting to the emergency department in the United States

OBJECTIVE

Fishing injuries commonly affect the hands. The goal of this study was to quantify the incidence of fishing-related upper extremity injuries that present to emergency departments in the United States.

METHODS

We examined the reported cases of fishing-related upper extremity injuries in the National Electronic Injury Surveillance System database. Analysis was performed based on age, sex and the type of injury reported.

RESULTS

The national incidence of fishing-related upper extremity injuries was 119.6 per 1 million person-years in 2014. The most common anatomic site for injury was the finger (63.3%), followed by the hand (20.3%). The most common type of injury in the upper extremity was the presence of a foreign body (70.4%). The incidence of fishing-related upper extremity injuries in males was 200 per 1 million person-years, which was significantly higher than the incidence in females (41 per 1 million person-years).

CONCLUSION

The incidence of fishing-related upper extremity injuries that present to the Emergency Department was 120 per 1 million person-years. The incidence was significantly higher in males. With the widespread popularity of the activity, it is important for Emergency Physicians and Hand Surgeons to understand how to properly evaluate and manage these injuries.

Approach to Aquatic Skin Infections

Aquatic-based infections can present a treatment challenge for primary care physicians because of the likely polymicrobial nature of the infection and the possibility of uncommon pathogenic organisms. Although Staphylococcus and Streptococcus species that colonize the skin are the most common etiologic agents associated with saltwater and freshwater skin and soft tissue infections, other significant pathogens can include Vibrio, Aeromonas, Edwardsiella, Erysipelothrix, and Mycobacterium. Early detection and appropriate management of aquatic infections can significantly decrease morbidity and mortality. This article reviews the pathophysiology, presentation, and management for the most common water-borne pathogens causing skin and soft tissue infections.

Non-tuberculous Mycobacterium species causing mycobacteriosis in farmed aquatic animals of South Africa

BACKGROUND

Mycobacteriosis caused by non-tuberculous mycobacteria (NTM), is among the most chronic diseases of aquatic animals. In addition, fish mycobacteriosis has substantial economic consequences especially in the aquaculture and fisheries industry as infections may significantly decrease production and trade. Some fish NTM pathogens are highly virulent and zoonotic; as such, infection of aquaria with these pathogens is a public health concern. In this study, we report isolation of nine different NTM species from sixteen aquatic animals including different fish species, frogs and a crocodile. Given the clinical significance of Mycobacterium marinum and its close relation to Mycobacterium tuberculosis, as well as the significance of ESAT 6 and CFP-10 secretion in mycobacterial virulence, we analysed the esxA and esxB nucleotide sequences of M. marinum isolates identified in this study as well as other mycobacteria in the public databases.

RESULTS

Mycobacterium shimoidei, Mycobacterium marinum, Mycobacterium chelonae, Mycobacterium septicum /M. peregrinum and Mycobacterium porcinum were isolated from gold fish, Guppy, exotic fish species in South Africa, koi and undefined fish, Knysna seahorse, as well Natal ghost frogs respectively, presenting tuberculosis like granuloma. Other NTM species were isolated from the studied aquatic animals without any visible lesions, and these include Mycobacterium sp. N845 T, Mycobacterium fortuitum, a member of the Mycobacterium avium complex, and Mycobacterium szulgai. Phylogenetic analysis of mycobacteria, based on esxA and esxB genes, separated slow growing from rapidly growing mycobacteria as well as pathogenic from non-pathogenic mycobacteria in some cases.

CONCLUSIONS

Isolation of the different NTM species from samples presenting granuloma suggests the significance of these NTM species in causing mycobacteriosis in these aquatic animals. The study also revealed the potential of esxA and esxB sequences as markers for phylogenetic classification of mycobacteria. Observations regarding use of esxA and esxB sequences for prediction of potential pathogenicity of mycobacteria warrants further investigation of these two genes in a study employing NTM species with well-defined pathogenicity.

Shewanella algae infection in Italy: report of 3 years' evaluation along the coast of the northern Adriatic Sea

Shewanella algae are Gram-negative, nonfermentative, motile bacilli, classified in the genus Shewanella in 1985. These environmental bacteria are occasionally identified in human infections, with a relatively strong association with exposure to seawater during warm seasons. This report describes a case series of 17 patients with infection correlated to S. algae in the coastal area of Romagna, Italy, from 2013 to 2016. The types of infection included otitis, pneumonia, sepsis and soft tissue (wound). Exposure to the marine environment during hot months was confirmed in 12 of 17 patients. An apparent correlation between increased severity of infection and patient age was also observed.

Case Report: Disseminated Shewanella algae Infection with Meningoencephalitis in a Traveler Secondary to Marine Injury in Madagascar

Marine microorganisms such as Shewanella spp., Vibrio spp., and Aeromonas spp. can cause sepsis secondary to a wound infection in the context of swimming. These microorganisms are most often susceptible to fluoroquinolones. Here, we report a unique case of Shewanella algae bacteremia associated with meningoencephalitis and disseminated via hematogenous spread secondary to a skin injury. The patient suffered the injury while swimming in saline water during a cruise holiday in Madagascar, and she was initially treated with amoxicillin. The neurological evolution was unsatisfactory. Better knowledge of such infections (and especially of the context in which they occur), as well as greater familiarity with the susceptibility profile of different marine microorganisms would have allowed health professionals to provide presumptive microbiological diagnosis and effective treatment earlier.

Soft tissue infections from fish spike wounds: normal commensal bacteria are more common than marine pathogens

BACKGROUND

A fish spike injury can be sustained by anyone handling fish; during fishing, meal preparation or in retail. Case reports of fish spikes inoculating victims with virulent marine-specific pathogens and causing systemic illness led us to question whether empirical treatment of these injuries with amoxicillin and clavulanic acid is adequate.

METHODS

This 2-year prospective observational study was conducted at Middlemore Hospital, Auckland, New Zealand. Wound swabs and tissue samples belonging to patients presenting to the Department of Plastic and Reconstructive Surgery with an upper limb fish spike injury were sent to the laboratory (n = 60). A series of stains and cultures were performed to look specifically for marine bacteria not typically isolated in other soft tissue injuries. Patient demographic data and injury details were collected.

RESULTS

Of the patients with adequate microbiology samples, 12% (6/50) grew clinically relevant bacteria resistant to amoxicillin and clavulanic acid. These included methicillin-resistant Staphylococcus aureus (8%, 4/50), Enterobacter cloacae (2%, 1/50) and an anaerobic sporing bacillus (2%, 1/50). Only one patient grew a true marine-specific bacteria, Photobacterium damselae, which was susceptible to amoxicillin and clavulanic acid.

CONCLUSION

The authors concluded that amoxicillin and clavulanic acid is an adequate first-line antibiotic for fish spike injuries but that flucloxacillin may be more appropriate given most bacteria were from patients' own skin flora. The authors suggest that clinicians consider the presence of resistant marine-specific bacteria in cases where there is sepsis or inadequate response to initial therapy.

Aeromonas as a Cause of Purulent Folliculitis: A Case Report and Review of the Literature

Aeromonas species are rarely an identified cause of folliculitis. Here, we describe the case of a patient who had purulent folliculitis of the breast caused by an Aeromonas species and review 4 other cases presented in the literature, highlighting the commonalities observed. Aeromonas infection should be considered in patients who present with purulent folliculitis, particularly those with exposure to nonchlorinated pools or baths.

Evaluation of anti-Erysipelothrix rhusiopathiae IgG response in bottlenose dolphins Tursiops truncatus to a commercial pig vaccine

Erysipelothrix rhusiopathiae is the causative agent of erysipeloid in humans and of erysipelas in various animals, including bottlenose dolphins Tursiops truncatus, in which an infection has the potential to cause peracute septicemia and death. The purpose of this study was to evaluate the efficacy of using an off-label porcine (ER BAC PLUS®, Zoetis) E. rhusiopathiae bactrin in a bottlenose dolphin vaccination program by determining the anti-E. rhusiopathiae antibody levels in vaccinated dolphins over a 10 yr period. Serum samples (n = 88) were analyzed using a modified fluorescent microbead immunoassay from 54 dolphins, including 3 individuals with no history of vaccination and 51 dolphins with an average of 5 vaccinations, 3 of which had previously recovered from a natural E. rhusiopathiae infection. A mean 311-fold increase in the immunoglobulin G (IgG) antibody index was measured in a subsample of 10 dolphins 14 d after the first booster vaccination. Serum IgG antibody titers were influenced by number of vaccines received (r2 = 0.47, p < 0.05) but not by age, gender, history of natural infection, adverse vaccine reaction, vaccination interval or time since last vaccination. The commercial pig bacterin was deemed effective in generating humoral immunity against E. rhusiopathiae in dolphins. However, since the probability of an adverse reaction toward the vaccine was moderately correlated (p = 0.07, r2 = 0.1) with number of vaccines administered, more research is needed to determine the optimal vaccination interval.

Traumatic Amputation of Finger From an Alligator Snapping Turtle Bite

Legend states that the alligator snapping turtle (Macrochelys temminckii) should be handled with extreme caution as it has jaw strength powerful enough to bite a wooden broomstick in half. Tales of bite injuries from what is the largest freshwater turtle in North America exist anecdotally, yet there are few descriptions of medical encounters for such. The risk of infection from reptilian bites to the hand in an aquatic environment warrants thorough antibiotic treatment in conjunction with hand surgery consultation. We present the first case report of a near total amputation of an index finger in an adolescent boy who had been bitten by a wild "gator snapper."

Mortality of therapeutic fish Garra rufa caused by Aeromonas sobria

OBJECTIVE

To investigate a case of mass mortality of Garra rufa (G. rufa) from a fish hatchery farm in Slovakia.

METHODS

Causative bacterial agent was swabbing out of affected fish skin area and subsequently identified using commercial test system. Antibiotic susceptibility was determined by the disk diffusion method.

RESULTS

Infected G. rufa was characterized by abnormal swimming behaviour, bleeding of skin lesions and local haemorrhages. Despite of using recommended aquatic antibiotic treatment no improvement was achieved and Aeromonas sobria (A. sobria) was identified as a causative agent of fish mortality. Due to massive fish mortality, antibiotic susceptibility of pure isolated culture of A. sobria was evaluated employing eight antibiotics against human infections. A. sobria was resistant only against one antibiotic, namely ampicilin.

CONCLUSIONS

These results indicate that A. sobria can act as a primary pathogen of G. rufa and may be a potential risk factor for immunodeficient or immunoincompetent patients during the ichthyotherapy.

Vibriosis

Vibriosis is a group of intestinal and extraintestinal infections caused by marine-dwelling bacteria of the genus Vibrio. Infections range from indolent illnesses to fulminant diseases, including cholera and necrotizing fasciitis. Most illnesses result from direct contact with the marine environment or consumption of shellfish, especially oysters. In the United States vibrio infections are increasing but are underreported because of lack of clinical recognition and appropriate detection in the microbiology laboratory. Recent advances to aid in the detection and identification of vibrio illnesses in the laboratory include rapid identification tests, new media, and molecular identification systems.

Tetanus after envenomations caused by freshwater stingrays

Injuries caused by freshwater stingray are common in several regions of South America, although they are underreported. The riverside inhabitants are the main victims in the Amazonian and Midwest regions of South America. The fishermen are injured mainly in the new focus of colonization of the rivers by freshwater stingrays. With the increasing population in these regions, where freshwater stingrays are found, there has been a significant increase in injuries within the general population. The highest increase occurred among tourists from other regions, where these animals are not known, when visiting these areas. The envenomations from the stingray causes prolonged and intense pain, both local and regionally. Generally these are associated with other local inflammatory manifestations, such as swelling and erythema. The injury often progresses to necrosis and it is considered potentially tetanogenic. A secondary infection is also a frequent local complication and most frequently is caused by Aeromonas species, usually Aeromonas hydrophila. Herein we report the first 2 cases of tetanus after freshwater stingray injuries: a 51-year-old men who had tetanus and recovered without sequel and the second a 67-year-old men who had severe tetanus and a deep, necrotizing soft-tissue infection with sepsis, septic shock and evolution to death.

Noma affected children from Niger have distinct oral microbial communities based on high-throughput sequencing of 16S rRNA gene fragments

We aim to understand the microbial ecology of noma (cancrum oris), a devastating ancient illness which causes severe facial disfigurement in>140,000 malnourished children every year. The cause of noma is still elusive. A chaotic mix of microbial infection, oral hygiene and weakened immune system likely contribute to the development of oral lesions. These lesions are a plausible entry point for unidentified microorganisms that trigger gangrenous facial infections. To catalog bacteria present in noma lesions and identify candidate noma-triggering organisms, we performed a cross-sectional sequencing study of 16S rRNA gene amplicons from sixty samples of gingival fluid from twelve healthy children, twelve children suffering from noma (lesion and healthy sites), and twelve children suffering from Acute Necrotizing Gingivitis (ANG) (lesion and healthy sites). Relative to healthy individuals, samples taken from lesions in diseased mouths were enriched with Spirochaetes and depleted for Proteobacteria. Samples taken from healthy sites of diseased mouths had proportions of Spirochaetes and Proteobacteria that were similar to healthy control individuals. Samples from noma mouths did not have a higher abundance of Fusobacterium, casting doubt on its role as a causative agent of noma. Microbial communities sampled from noma and ANG lesions were dominated by the same Prevotella intermedia OTU, which was much less abundant in healthy sites sampled from the same mouths. Multivariate analysis confirmed that bacterial communities in healthy and lesion sites were significantly different. Several OTUs in the Orders Erysipelotrichales, Clostridiales, Bacteroidales, and Spirochaetales were identified as indicators of noma, suggesting that one or more microbes within these Orders is associated with the development of noma lesions. Future studies should include longitudinal sampling of viral and microbial components of this community, before and early in noma lesion development.

Noma is a traumatic disease characterized by oral-facial lesions that often lead to severe disfigurement and ultimately shame and isolation from the community. Because the causes of noma are likely to be numerous, and reaching those who suffer from this illness is challenging, the etiology of noma remains ill-defined. Although it is known that oral hygiene and nutrition influence the development of noma, evidence suggests that one or more microbes play a crucial role in development of noma lesions. Previous studies have examined the DNA of microbes in lesions to determine which species are present and how their abundances differ between healthy mouth sites and noma lesions. These studies used techniques that were state-of-the-art at the time, though we know they likely only scratched the surface of the resident microbial diversity. Here we extend these studies by digging deeper to characterize a larger diversity of microbial species in noma and control samples, with the goal of better identifying which microbes are uniquely present or have altered abundances in noma lesions.

Zebrafish as a model for zoonotic aquatic pathogens

Aquatic habitats harbor a multitude of bacterial species. Many of these bacteria can act as pathogens to aquatic species and/or non-aquatic organisms, including humans, that come into contact with contaminated water sources or colonized aquatic organisms. In many instances, the bacteria are not pathogenic to the aquatic species they colonize and are only considered pathogens when they come into contact with humans. There is a general lack of knowledge about how the environmental lifestyle of these pathogens allows them to persist, replicate and produce the necessary pathogenic mechanisms to successfully transmit to the human host and cause disease. Recently, the zebrafish infectious disease model has emerged as an ideal system for examining aquatic pathogens, both in the aquatic environment and during infection of the human host. This review will focus on how the zebrafish has been used successfully to analyze the pathogenesis of aquatic bacterial pathogens.

Skin and soft tissue infections following marine injuries and exposures in travelers

BACKGROUND

Bacterial skin and soft tissue infections (SSTIs) in travelers often follow insect bites and can present a broad spectrum of clinical manifestations ranging from impetigo to necrotizing cellulitis. Significant SSTIs can also follow marine injuries and exposures in travelers, and the etiologies are often marine bacteria.

METHODS

To meet the objectives of describing the pathogen-specific presenting clinical manifestations, diagnostic and treatment strategies, and outcomes of superficial and deep invasive infections in travelers caused by commonly encountered and newly emerging marine bacterial pathogens, Internet search engines were queried with the key words as MESH terms.

RESULTS

Travel medicine practitioners should maintain a high index of suspicion regarding potentially catastrophic, invasive bacterial infections, especially Aeromonas hydrophila, Vibrio vulnificus, Chromobacterium violaceum, and Shewanella infections, following marine injuries and exposures.

CONCLUSIONS

Travelers with well-known risk factors for the increasing severity of marine infections, including those with open wounds, suppressed immune systems, liver disease, alcoholism, hemochromatosis, hematological disease, diabetes, chronic renal disease, acquired immunodeficiency syndrome, and cancer, should be cautioned about the risks of marine infections through exposures to marine animals, seawater, the preparation of live or freshly killed seafood, and the accidental ingestion of seawater or consumption of raw or undercooked seafood, especially shellfish. With the exception of minor marine wounds demonstrating localized cellulitis or spreading erysipeloid-type reactions, most other marine infections and all Gram-negative and mycobacterial marine infections will require therapy with antibiotic combinations.

Rapid detection and identification of nontuberculous mycobacterial pathogens in fish by using high-resolution melting analysis

Mycobacterial infections in fish are commonly referred to as piscine mycobacteriosis, irrespectively of the specific identity of the causal organism. They usually cause a chronic disease and sometimes may result in high mortalities and severe economic losses. Nearly 20 species of Mycobacterium have been reported to infect fish. Among them, Mycobacterium marinum, M. fortuitum, and M. chelonae are generally considered the major agents responsible for fish mycobacteriosis. As no quick and inexpensive diagnostic test exists, we tested the potential of high-resolution melting analysis (HRMA) to rapidly identify and differentiate several Mycobacterium species involved in fish infections. By analyzing both the melting temperature and melting profile of the 16S-23S rRNA internal transcribed spacer (ITS), we were able to discriminate 12 different species simultaneously. Sensitivity tests conducted on purified M. marinum and M. fortuitum DNA revealed a limit of detection of 10 genome equivalents per reaction. The primers used in this procedure did not lead to any amplification signal with 16 control non-Mycobacterium species, thereby demonstrating their specificity for the genus Mycobacterium.

Human infection with Shewanella putrefaciens and S. algae: report of 16 cases in Martinique and review of the literature

Shewanella spp. are saprophytic bacteria that are part of the marine microflora in warm climates and are rarely pathogenic. However, Shewanella spp. infections are being increasingly reported, and there has been no comprehensive review of the literature describing these infections. This article reports 16 cases of Shewanella spp. infections in Martinique since 1997 and reviews another 239 cases reported in the literature since 1973. Patients experienced soft tissue infections, ear infection, or abdominal and biliary tract infections. A skin or mucosal portal of entry was found for 53% of the patients and exposure to the marine environment was reported for 44%; 79% of patients had an underlying condition. Bacteriema were frequent (28%). Most (87%) patients recovered, although ear infections can become chronic. Death occurred in 13% of the patients. Most Shewanella spp. isolates are susceptible to cefotaxime (95%), piperacillin and tazobactam (98%), gentamicin (99%), and ciprofloxacin (94%).

Erysipelothrix rhusiopathiae isolates recovered from fish, a harbour seal (Phoca vitulina) and the marine environment are capable of inducing characteristic cutaneous lesions in pigs

In order to determine the diversity and pathogenicity of Erysipelothrix spp. isolates recovered from marine fish, a harbour seal (Phoca vitulina) and the marine environment, 14 isolates were characterized by genotyping, serotyping, determination of the surface protective antigen (spa) gene type and assessment of virulence in a pig bioassay. All 14 isolates were Erysipelothrix rhusiopathiae. Isolates were determined to be of serotypes 2 (n = 3), 3 (n = 1), 4 (n = 1), 12 (n = 1), 15 (n = 1) or 21 (n = 6), and one isolate cross-reacted with serotypes 5 and 21. The spa gene analysis determined that 64.3% (n = 9) were spaA and 35.7% (n = 5) were spaB1. In pigs, 10/14 isolates induced small plaques to diamond-shaped cutaneous lesions consistent with Erysipelothrix spp. infection. The results of this study indicate that the marine E. rhusiopathiae isolates have greater genetic and antigenic diversity than pig isolates and are capable of inducing classical skin lesions in pigs.

Genetic diversity and population structure of Mycobacterium marinum: new insights into host and environmental specificities

Mycobacterium marinum causes a systemic tuberculosis-like disease in fish and skin infections in humans that can spread to deeper structures, resulting in tenosynovitis, arthritis, and osteomyelitis. However, little information is available concerning (i) the intraspecific genetic diversity of M. marinum isolated from humans and animals; (ii) M. marinum genotype circulation in the different ecosystems, and (iii) the link between M. marinum genetic diversity and hosts (humans and fish). Here, we conducted a genetic study on 89 M. marinum isolates from humans (n = 68) and fish (n = 21) by using mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) typing. The results show that the M. marinum population is genetically structured not only according to the host but also according to the ecosystem as well as to tissue tropism in humans. This suggests the existence of different genetic pools in the function of the biological and ecological compartments. Moreover, the presence of only certain M. marinum genotypes in humans suggests a different zoonotic potential of the M. marinum genotypes. Considering that the infection is linked to aquarium activity, a significant genetic difference was also detected when the human tissue tropism of M. marinum was taken into consideration, with a higher genetic polymorphism in strains isolated from patients with cutaneous forms than from individuals with deeper-structure infection. It appears that only few genotypes can produce deeper infections in humans, suggesting that the immune system might play a filtering role.

Epidemiology and pathogenicity of zoonotic streptococci

Zoonotic infections caused by Streptococcus spp. have been neglected in spite of the fact that frequency and severity of outbreaks increased dramatically in recent years. This may be due to non-identification since respective species are often not considered in human medical diagnostic procedures. On the other hand, an expanding human population concomitant with an increasing demand for food and the increased number of companion animals favour conditions for host species adaptation of animal streptococci. This review aims to give an overview on streptococcal zoonoses with focus on epidemiology and pathogenicity of four major zoonotic species, Streptococcus canis, Streptococcus equi sub. zooepidemicus, Streptococcus iniae and Streptococcus suis.