Post-traumatic skin and soft tissue infection due to Aeromonas hydrophila

Occurrence of Antibiotic-Resistant Bacteria and Genes in Two Drinking Water Treatment and Distribution Systems in the North-West Province of South Africa

With the increasing spread of antimicrobial resistance, there is growing attention to the contribution made by drinking water systems. The potential health impact of two drinking water treatment and distribution systems (A and B) in the North-West Province of South Africa was determined by investigating the water quality and occurrence of antimicrobial-resistant heterotrophic bacteria and genes in the raw and treated water over four seasons. Most of the physicochemical parameters except for electrical conductivity were within permissible limits. Coliform bacteria reduced from raw to potable water except for counts higher than the threshold recorded in Summer and Winter. A total of 203 heterotrophic bacterial isolates were recovered on chromogenic R2A medium and subjected to susceptibility testing to twelve antibiotics. Most of the isolates were resistant to β-lactam antibiotics and Trimethoprim, whereas they were susceptible to Ciprofloxacin, Erythromycin, and Neomycin. The proportions of Cephalothin and Kanamycin-resistant isolates were significantly higher (p < 0.05) after treatment for site A, compared to significantly lower β-lactam, Oxytetracycline, and Trimethoprim-resistant isolates for B. Over 50% of isolates were of high risk, indicating their origin from high antibiotic-use sources. Seventy-one (35%) isolates were multidrug-resistant, out of which the majority (53.5%, n = 38) possessed the strA gene, followed by strB 21 (29.6%), dfrB 13 (18.3%), aadA 11 (15.5%), bla_CTX-M 5 (7.0%), and tetA 3 (4.2%). The 16S rRNA gene sequences of the isolates revealed strains belonging to eight bacterial families, some of which are clinically important.

Bone graft donor site infection with a rare organism, Aeromonas Hydrophila. A typical location, presentation and organism with 2 years follow-up. Case report

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A. Hydrophila found in immunocompromised patients, burns or aquatic trauma patients.

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Aeromonas produce β-lactamase making it resistant to usual prophylactic antibiotics.

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Early surgical and antibiotic treatment is essential.

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Following a multidisciplinary approach, these patients avoid catastrophic results.

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Combined case report with detailed review of A. Hydrophila from recent literature.

Introduction

Aeromonas are Gram-negative bacilli often causing necrotizing fasciitis or sepsis in immunocompromised patients. Aeromonas Hydrophila is most often found in immunocompromised patients or those with burns or aquatic trauma. When patients present with a discharge and infection on bone graft donor site and progressive sepsis, an Aeromonas hydrophila infection should be considered in the differential diagnosis.

Presentation of case

We report here a rare case of Aeromonas hydrophila with surgical site sepsis/infection in an immunocompromised 69 years old female, with several comorbids. Here we are reporting infection on donor surgical graft site, sparing major surgical site with the implant. After getting culture report of exudates from the wound that grew A. hydrophila, immediate wound debridement and antibiotic beads insertion was performed with appropriate antimicrobial therapy and regular wound dressing. She was followed for around 2 years.

Discussion

This is the first report to our knowledge of A. Hydrophila infection in bone graft donor site. Aeromonas most often cause gastrointestinal and soft tissue infections, and bacteremia in immunocompromised patients. Early surgical intervention is essential to reducing mortality in deep soft tissue infections caused by this organism. Aeromonas have shown resistance to penicillin but are sensitive to other broad-spectrum antibiotics.

Conclusion

Early suspicion, diagnosis, and treatment with potent antibiotics are needed to prevent any further complications resulting from infection by this emerging aggressive pathogen.

The prevalence of multidrug-resistant Aeromonas spp. in the municipal wastewater system and their dissemination in the environment

The objective of this study was to identify the determinants of antibiotic resistance and virulence of Aeromonas spp. isolated from treated wastewater (WW) and from samples of river water collected upstream (URW) and downstream (DRW) from the effluent discharge point. The resistance of Aeromonas spp. to antibiotics that are widely used in human and veterinary medicine, including beta-lactams, tetracyclines, glycylcyclines, fluoroquinolones, aminoglycosides and sulfamethoxazole-trimethoprim, was analyzed by disk diffusion method. The prevalence of hemolysins, aerolysins (virulence factors) and integrase genes was determined. A total of 83 Aeromonas spp. strains were selected from the isolates obtained from river water and wastewater samples. The highest percentage (81.8%) of multidrug-resistant isolates was noted in DRW samples. The analyzed isolates were most frequently resistant to beta-lactams, tetracyclines and aminoglycosides, whereas resistance to glycylcyclines was least common. Isolates resistant to beta-lactams most frequently harbored bla_TEM and bla_OXA genes. The group of genes encoding resistance to tetracyclines was most frequently represented by tet(E) and tet(O). Genes encoding virulence ahh1 (heat-labile hemolysin) or integrase intI1 occurred more frequently in the strains isolated from DRW than URW. An analysis of genetic relatedness revealed two main clusters - one with closely related WW and DRW isolates and one with less related isolates from all analyzed samples. The results of this study indicate that regardless of the applied treatment, municipal sewage may be a reservoir of antibiotic-resistant bacteria, antibiotic resistance and virulence genes and that treated water can contaminate other environmental domains.

Chronic osteomyelitis by Aeromonas hydrophila: A silent cause of concern

Aeromonas is a Gram-negative bacillus, widely found in aquatic environment. Osteoarticular pathology caused by Aeromonas hydrophila is rarely encountered. To the best of our knowledge, this is the first case of chronic osteomyelitis by A. hydrophila reported from India. We report a case of chronic osteomyelitis of the lower limb due to A. hydrophila, which occurred as a delayed complication following open reduction and internal fixation. Prompt medical and surgical intervention supplemented by a comprehensive microbiological workup aided in pathogen identification and specific antimicrobial administration resulting in the successful outcome of our patient. This case illustrates the utility of multidisciplinary management approach involving microbiologists and orthopedicians in investigating and appropriately managing such cases.

Establishment of Infection Models in Zebrafish Larvae (Danio rerio) to Study the Pathogenesis of Aeromonas hydrophila

Aeromonas hydrophila is a Gram-negative opportunistic pathogen of fish and terrestrial animals. In humans, A. hydrophila mainly causes gastroenteritis, septicaemia, and tissue infections. The mechanisms of infection, the main virulence factors and the host immune response triggered by A. hydrophila have been studied in detail using murine models and adult fish. However, the great limitation of studying adult animals is that the animal must be sacrificed and its tissues/organs extracted, which prevents the study of the infectious processes in the whole living animal. Zebrafish larvae are being used for the analysis of several infectious diseases, but their use for studying the pathogenesis of A. hydrophila has never been explored. The great advantage of zebrafish larvae is their transparency during the first week after fertilization, which allows detailed descriptions of the infectious processes using in vivo imaging techniques such as differential interferential contrast (DIC) and fluorescence microscopy. Moreover, the availability of fluorescent pathogens and transgenic reporter zebrafish lines expressing fluorescent immune cells, immune marker genes or cytokines/chemokines allows the host-pathogen interactions to be characterized. The present study explores the suitability of zebrafish larvae to study the pathogenesis of A. hydrophila and the interaction mechanisms between the bacterium and the innate immune responses through an infection model using different routes for infection. We used an early-embryo infection model at 3 days post-fertilization (dpf) through the microinjection of A. hydrophila into the duct of Cuvier, caudal vein, notochord, or muscle and two bath infection models using 4 dpf healthy and injured larvae. The latter resembled the natural conditions under which A. hydrophila produces infectious diseases in animals. We compared the cellular processes after infection in each anatomical site by confocal fluorescence imaging and determined the implication of inflammatory immune genes by measuring gene expression by qPCR.

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.

Surgical Site Infection Caused by Aeromonas hydrophila in a Patient with Underlying Malignancy

Aeromonas skin and soft tissue infections in cancer patients can lead to serious life threatening conditions such as cellulitis, necrotizing fasciitis and myonecrosis. We report here a case of surgical site infection, post radical mastectomy, in a 58-year-old female with carcinoma breast. Cultures of exudates from the wound grew Aeromonas hydrophila on repeated occasions. Recovery was uneventful following targeted antimicrobial therapy and regular dressing of the wound. Early suspicion, diagnosis, and treatment with potent antibiotics are needed to prevent any further complications resulting from infection by this emerging pathogen.

Chinese herbal medicines for treating skin and soft-tissue infections

BACKGROUND

Skin and soft-tissue infections (SSTIs) are common infections of the epidermis, dermis or subcutaneous tissue. SSTIs range in severity from minor, self-limiting, superficial infections to deep, aggressive, gangrenous, life-threatening infections. Some classifications divide SSTIs into 'complicated' and 'uncomplicated' infections based on clinical severity. Treatments of SSTIs involves antibiotic therapy, surgical debridement or drainage, and resuscitation if required. Sometimes these treatments are limited by high treatment costs, bacterial resistance to antibiotics and side effects, therefore, many people with SSTIs are turning to Chinese herbal medicines to treat this problem.Chinese herbal medicines are natural substances that have been used for centuries in China where they are generally considered to be effective for SSTIs. Some Chinese herbal medicines have been shown to have antibacterial and anti-inflammatory properties, although a few herbal medicines have been reported to have side effects. Therefore there is a need to review the current clinical evidence systematically to inform current practice and guide future studies on Chinese herbal medicines for SSTIs.

OBJECTIVES

To evaluate the benefits and harms of Chinese herbal medicines for treating skin and soft-tissue infections (SSTIs).

SEARCH METHODS

Searches were not restricted by date, language or publication status. In July 2014 we searched the following electronic databases: the Cochrane Wounds Group Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; Ovid AMED (Allied and Complementary Medicine); and EBSCO CINAHL.

SELECTION CRITERIA

All randomised controlled trials (RCTs) in people with SSTIs that compared Chinese herbal medicines with another intervention or control.

DATA COLLECTION AND ANALYSIS

Two review authors screened the literature search results independently; there were no disagreements.

MAIN RESULTS

We identified no RCTs that met the inclusion criteria.

AUTHORS' CONCLUSIONS

There is currently no information available from RCTs to support or refute the use of Chinese herbal medicines in treating people with SSTIs.

Fatal Necrotizing Soft Tissue Infection by Aeromonas hydrophila

Aeromonas infections in healthy individuals are self limiting, but those in patients with immuno-compromised conditions are frequently associated with significant morbidity and mortality. The current case report describes a fatal case of necrotizing soft tissue infection by Aeromonas hydrophila in an immuno-competent patient.

Necrotizing fasciitis caused by Aeromonas caviae

Aeromonads are rarely associated with human intestinal and extra-intestinal diseases and syndromes, ranging from relatively mild illnesses such as acute gastroenteritis to life-threatening conditions, including septicemia, necrotizing fasciitis, and myonecrosis. Among the aeromonas species known to cause human infection, Aeromonas caviae has been associated with septicemia and only one reported case of human soft tissue infection. Most of the infections due to aeromonas occur in immunocompromised patients. Herein we describe a successfully treated case of post-traumatic skin and soft-tissue infections due to A. caviae in an otherwise immunocompetent individual.