[Sepsis caused by Raoultella ornithinolytica in an immunocompetent patient]

Analysis of Anti-Infective Treatment of 9 Neonates with Raoultella ornithinolytica Sepsis

Raoul ornithine-releasing bacteria widely exist in water, plants, and soil, and colonize the digestive tract and upper respiratory tract of the human body. They are aerobic, unpowered, and capsular opportunistic pathogens. The infectivity of this bacterium is still uncertain, but the possibility of nosocomial infection has been mentioned in the literature. Studies have pointed out that the bacterium should be diagnosed in time and sensitive antibiotics should be used early. Once complicated with sepsis, it can cause multiple organ failure with a poor prognosis. In this study, we retrospectively analyzed the clinical data of nine cases of neonatal L. ornithine septicemia, to explore the clinical characteristics of neonatal L. ornithine septicemia and anti-infection therapy.

Sepsis From Multisystem Infection With Multidrug-Resistant Raoultella ornithinolytica

Raoultella (R.) ornithinolytica is a gram-negative, encapsulated aerobe or facultative anaerobe belonging to the family Enterobacteriaceae. It is distinguished from other members in the family with a negative indole test, growth at 10^oC, production of histamine, a negative D-melezitose test, and metabolism of ornithine. R. ornithinolytica is a versatile organism found in different habitats, including soil, water, and plants, as well as colonizing the human gastrointestinal tract and throat. It was considered to cause opportunistic infection in humans but is increasingly being implicated in infections in immunocompetent individuals. Raoultella ornithinolytica causes infection in different clinical settings. Sepsis from Raoultella ornithinolytica is increasing among humans, and it is considered an emerging infectious agent in both immunocompromised and immunocompetent people. There is an increasing level of antibiotic resistance among isolates with reports of multidrug resistance.

We report the case of a 95-year-old man with multidrug-resistant R. ornithinolytica multisystem infection and review the literature.

A spotlight on Raoultella ornithinolytica: A newly emerging life-threatening zoonotic pathogen

The genus Raoultella contains Raoultella ornithinolytica (R. ornithinolytica), which was previously named as Klebsiella ornithinolytica. R. ornithinolytica is a Gram-negative bacillus that belongs to the family Enterobacteriaceae. This pathogen is normally present in aquaculture, and it has been isolated from fish, insects, and wild and domestic birds. Seafood and poultry products are incriminated as sources of R. ornithinolytica infection. Community-acquired human infection with R. ornithinolytica is common. This infection is commonly associated with sepsis, bacteremia, food poisoning, purities, and urinary and respiratory tracts' infections. Rapid acquired resistance of R. ornithinolytica strains is common, and it is related to the development of resistant genes. R. ornithinolytica is considered as a newly emerging life-threatening pathogen world-wide. Hence, it is very important to determine the role of animals and birds in the epidemiological situation of this pathogen as well as the detection of antibiotic resistance genes before treatment.

Emergence of Raoultella ornithinolytica isolated from chicken products in Alexandria, Egypt

Background and Aim:

Raoultella ornithinolytica is one of the emerging gram-negative bacteria, which associated with foodborne illness. Researches affirmed that distinguish between R. ornithinolytica and Klebsiella oxytoca are difficult, as they are phylogenetic related. The evolution of multidrug resistance of Raoultella strains gained more concern for recognition of the pathogen which supports in controlling the disease and minify its threat. This study sought to find a reliable tool for the identification of Raoultella ornithinolytica, isolated from chicken product samples, and assessed the resistance profile of R. ornithinolytica using antibiogram sensitivity tests.

Materials and Methods:

Forty samples of chicken products were collected between January and September 2019 from different markets in Alexandria Governorate, Egypt. The products included nuggets, strips, burgers, luncheon meats, pane, frankfurters, and minced chicken meat. The samples were transferred to the Reference Laboratory. The samples were subjected to isolation, biochemical reaction testing, phenotypic system analytical profile index (API) E20, and a detection of antimicrobial susceptibility test. Phenotypic identification was confirmed through matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS).

Results:

Thirty-three bacterial isolates (82.50%) out of 40 samples were isolated into pure cultures from the chicken samples. Three isolates (9.09%) were positive for R. ornithinolytica, while 30 isolates (90.91%) exhibited growth characters for different pathogens (Escherichia coli, Enterobacter aerogenes, Proteus vulgaris, R. ornithinolytica, and Klebsiella pneumoniae). The isolates of R. ornithinolytica were resistant to five types of antibiotics and sensitive to two types of antibiotics.

Conclusion:

This study reported the first case of R. ornithinolytica found in chicken products in Egypt. Phenotypic system API 20E and MALDI-TOF MS were found to be reliable tools for confirming the diagnosis of R. ornithinolytica. As it provides rapid identification with high sensitivity and specificity for R. ornithinolytica, which often do not require a molecular procedure for confirmation.

Fat necrosis and polymicrobial wound infection caused partly by Raoultella ornithinolytica after reduction mammoplasty

Raoultella ornithinolytica is a rare opportunistic aerobic gram-negative bacillus that naturally exists in soil, water and plants. The pathogen has been described in association with diabetic foot infections, biliary infections, bacteraemia and native and prosthetic joint infections. Fat necrosis and wound infection following breast reduction surgery or other plastic surgeries caused by this pathogen have not been previously described. We present a case of bilateral fat necrosis, wound infection and dehiscence in a 24-year-old woman with no significant past medical problems. She initially had an uneventful early postoperative course but 3 weeks after surgery noticed pain and discharge from both nipple/areola area of both breasts which later developed into full-thickness fat necrosis and complete destruction of the nipple areolar complex. R. ornithinolytica, Escherichia coli and Enterococcus faecalis were identified from wound exudate cultures. She was treated with surgical debridement and 2 weeks of appropriate antibiotics with a favourable outcome.