Recovery of an unusual Flavobacterium group IIb-like isolate from a hand infection following pig bite

Association of Myroides odoratimimus in immunocompromized piglets with post weaning multisystemic wasting syndrome

AIM

To study the association of opportunistic infection due to Myroides odoratimimus in piglets immunocompromised by porcine circovirus type 2 (PCV2) infection.

METHODS AND RESULTS

The clinical samples (n = 101) were analysed bacteriologically. The isolates were identified by their phenotypes and MALDI TOF-MS analysis as Myroides species. The phylogram constructed based on nucleotide sequences of the 16S rRNA gene showed identity (~99%) with the M. odoratimimus isolates. The minimum inhibitory concentration values for antibiotics revealed M. odoratimimus to be resistant against carbapenem, cephalosporins, aminoglycosides and fluoroquinolones. The presence of PCV2 in affected tissue samples was confirmed by amplification of the 565 bp region of ORF2 of the PCV2 genome. The topology of the phylogenetic tree grouped the PCV2 with cluster-2d.

CONCLUSIONS

PCV2 being immunosuppressive in nature might have impaired the immunity thereby increasing the susceptibility of immunocompromised piglets to opportunistic pathogens such as M. odoratimimus leading to disease severity and high mortality. The M. odoratimimus isolates were found to be multidrug resistant and evidenced for uncertain clinical relevance and hence could act as hidden source of public health hazard.

SIGNIFICANCE AND IMPACT OF THE STUDY

Myroides odoratimimus is a rarely reported human pathogen. We reported the incidence of infection due to seemingly rare isolates of M. odoratimimus causing an outbreak of pneumonia in piglets. This appears, to the best of authors' knowledge, to be the first outbreak due to Myroides recorded in animal clinical cases described in the literature.

Fatal case of necrotizing fasciitis due to Myroides odoratus

Myroides sp., previously known as Flavobacterium odoratum, is a relatively unknown organism with unclear human pathogenicity. While Myroides sp. has been implicated in human infections, many reports have described the organism as a relatively avirulent opportunistic pathogen. We present an unusual case of rapidly fatal necrotizing fasciitis and septic shock due to Myroides odoratus. Our case demonstrates the pathogenicity of Myroides, and highlights potential risk factors for infection including underlying liver disease and open wounds. The recognition of Myroides is of particular importance given its resistance to multiple antibiotics. We review the literature on Myroides sp. skin and soft tissue infections, including necrotizing forms, and discuss the clinical presentation and management of this potentially emerging pathogen.

Myroides odoratimimus soft tissue infection in an immunocompetent child following a pig bite: case report and literature review

Members of the genus Myroides are aerobic Gram-negative bacteria that are common in environmental sources, but are not components of the normal human microflora. Myroides organisms behave as low-grade opportunistic pathogens, causing infections in severely immunocompromised patients and rarely, in immunocompetent hosts. A case of Myroides odoratimimus cellulitis following a pig bite in an immunocompetent child is presented, and the medical literature on Myroides spp. soft tissue infections is reviewed.

Microbiology of animal bite wound infections

The microbiology of animal bite wound infections in humans is often polymicrobial, with a broad mixture of aerobic and anaerobic microorganisms. Bacteria recovered from infected bite wounds are most often reflective of the oral flora of the biting animal, which can also be influenced by the microbiome of their ingested prey and other foods. Bacteria may also originate from the victim's own skin or the physical environment at the time of injury. Our review has focused on bite wound infections in humans from dogs, cats, and a variety of other animals such as monkeys, bears, pigs, ferrets, horses, sheep, Tasmanian devils, snakes, Komodo dragons, monitor lizards, iguanas, alligators/crocodiles, rats, guinea pigs, hamsters, prairie dogs, swans, and sharks. The medical literature in this area has been made up mostly of small case series or case reports. Very few studies have been systematic and are often limited to dog or cat bite injuries. Limitations of studies include a lack of established or inconsistent criteria for an infected wound and a failure to utilize optimal techniques in pathogen isolation, especially for anaerobic organisms. There is also a lack of an understanding of the pathogenic significance of all cultured organisms. Gathering information and conducting research in a more systematic and methodical fashion through an organized research network, including zoos, veterinary practices, and rural clinics and hospitals, are needed to better define the microbiology of animal bite wound infections in humans.

Animal bite-associated infections: microbiology and treatment

Human and animal bites may lead to serious infection. The organisms involved tend to originate from the oral cavity of the offending biter, as well as the environment where the injury occurred. A variety of aerobic as well as anaerobic organisms have been isolated from bite wounds, with infection ranging from localized cellulitis to systemic dissemination, leading to severe disease ranging from abscess to bone and joint infection, to endocarditis and brain abscess. Immediate wound management, including recognition of the most commonly associated infectious pathogens, and judicious use of empiric antibiotics are crucial in providing the best care after a bite. Here, we discuss the common animal bite associated infections, and provide the most up to date information regarding their management.

Review article: Animal bites: an update for management with a focus on infections

Animal bites are a significant public health problem, with an estimated 2% of the population bitten each year. The majority of bites are from dogs and risk factors include young children, men, certain dog breeds and unrestrained dogs. The risk of infection following bites differs among animal species and is dependent on animal dentition and oral flora. Recent studies have demonstrated a broad range of pathogens isolated from infected bite wounds, with Pasteurella species being the predominant isolate from dog and cat bite wounds. Controversy exists about the use of prophylactic antibiotics; however, they are currently only recommended for high-risk bite wounds. Two fatal cases of Australian bat lyssavirus have been reported and bats are the only identified reservoir in Australia. All bat bites are of high risk and should receive post-exposure prophylaxis for rabies. Workers handling bats should be offered routine immunization.

Wild Boar Attacks

Attacks on humans by wild boar (Sus scrofa) are occasionally reported in rural areas of Turkey. While fatalities are rare, individuals may sustain significant soft tissue trauma. Lower extremity lacerations of up to 10 cm in length and 4 cm deep were seen in the 3 cases reviewed. Injuries to the upper abdomen and chest occurred in one case. Attacks frequently occur in forested areas covered by dense brushwood, and their incidence is increased during the rutting season. In contrast to other large, feral animal attacks, injuries sustained from wild boar typically are limited to the lower extremities. This case series examines 3 attacks by wild boar in rural Turkey.

Hospital management of animal and human bites

The management of bites severe enough to warrant hospital admission is complex. This review includes the epidemiology, clinical management, investigations, microbiology and role of antimicrobials for all types of animal and human bites likely to be encountered in UK hospitals.

Management of human and animal bite wounds: an overview

Serious infections can result from wounds that are caused by bites from animals and humans. Organisms recovered from bite wounds generally originate from the oral cavity of the biting animal, as well as from the patient's skin flora. Anaerobes have been isolated from animal and human bite wound infections, especially those associated with abscess formation. In addition to local wound infections, common complications, such as lymphangitis, septic arthritis, tenosynovitis, and osteomyelitis, and uncommon complications, such as endocarditis, meningitis, brain abscess, and sepsis, may occur. Wound management includes proper local care and, when needed, antimicrobial therapy.

North American wild mammalian injuries

Wild animal injuries are distinct from other injuries sustained by humans; tearing, cutting, penetrating, and crushing injuries are sometimes combined with falls and large animal forces causing blunt trauma. Bites from attacking animals may cause local infection, and wounds are potentially contaminated with a variety of pathogens. In addition, animals can transmit systemic diseases, many of which induce substantial morbidity and mortality. To compound the problem, many animal attacks occur in remote or wilderness areas and involve substantial delays in the time to notification, rescue, and presentation to definitive care. This article discusses attacks by the most common North American wild mammals.

Microbiology and management of human and animal bite wound infections

This article describes the microbiology, diagnosis, and management of human and animal bite wound infections. Various organisms can be recovered from bite wounds that generally result from aerobic and anaerobic microbial flora of the oral cavity of the biting animal, rather than the victim's own skin flora. The role of anaerobes in bite wound infections has been increasingly appreciated. Anaerobes were isolated from more than two thirds of human and animal bite wound infections, especially those associated with abscess formation. This article describes several of the organisms found in the bites of various species. In addition to local wound infection, other complications may occur, including lymphangitis, local abscess, septic arthritis, tenosynovitis, and osteomyelitis. Rare complications include endocarditis, meningitis, brain abscess, and sepsis with disseminated intravascular coagulation, especially in immunocompromised individuals. Wound management includes the administration of proper local care and the use of proper antimicrobial agents when needed.

Overview of the etiology of wound infections with particular emphasis on community-acquired illnesses

Wound cultures represent a general catchall category for a group of extremely diverse anatomic samples that range from superficial specimens of cutaneous structures (folliculitis, cellulitis) to specimens revealing invasive infections involving deep fascial planes and muscle (myonecrosis). Because of the complex nature of these infective processes, the terminology associated with such infections is often imprecise and confusing. Wounds are the result of trauma, either intentionally or accidentally induced. Nosocomial wound infections result primarily from surgical procedures, the development of pressure sores, or catheterization. Community-acquired wound infections are often preceded by injuries resulting from occupational exposure or recreational activities and are associated with a greater diversity of microorganisms due to the exposure of open wounds to inhabitants of the microbial biosphere. This review provides a general overview of the categories of wound infections and describes their acquisition and clinical significance. Particular emphasis is placed on selected community-acquired wound infections and the etiologic agents associated with such conditions.

Pig bite in Brazil: a case series from a teaching hospital

A retrospective survey done from 1987 till 1990 revealed that 23 patients bitten by pigs sought medical help at a teaching hospital in Uberlândia, in southeastern Brazil. Most cases (21) were from Uberlândia. The cases were evenly distributed by month and by year; most of them (14/16; 87.5%) occurred between 7.00 a.m. and 7.00 p.m. The male to female ratio was 6.7:1. Age ranged from 6 to 73 (mean 38.95 +/- SD 22.06, median 36). The bites were more common on the upper limbs, particularly on the forearms. In 11 (47.8%) cases the injury was described as deep. In most cases where information was available the injury was related to capture, transport or immobilisation of the pig for slaughter. The following medical procedures were performed: local cleansing in 19(82.6%) cases, rabies vaccine (12; 52.2%), antirabies serum (2; 8.7%), suturing (6; 26.1%) and tetanus vaccine (12; 52.2%). There was no case of infection at the bite site, neither of rabies or tetanus. By our data, the annual incidence of pig bite in Uberlândia can be estimated to be about 1.5/100,000.