Infections on the rise: Raoultella spp., clinical and microbiological findings from a retrospective study, 2010-2014

Clinical Characteristics of Abdominal Infections Caused by Raoultella Spp.: A Retrospective Study

Background: In recent years, Raoultella spp. have attracted clinical attention as a new type of pathogen. The most common of human infection with Raoultella are bacteremia, urinary tract infections, abdominal infections, etc. Abdominal infection is a serious and complex infection problem. However, there have been no systematic reports of abdominal infections caused by Raoultella. The objective of this study was to explore the clinical characteristics of Raoultella abdominal infections and provide a reference for clinical practice. Methods: A review of publications on abdominal infections caused by the genus Raoultella between 2009 and 2024 is carried out. This review studied seven parameters: infection type, number of cases, gender, age, comorbidities, treatment, and outcome, and descriptive statistical methods were used to analyze the results. Results: A total of 40 cases (16 Raoultella ornithinolytica and 24 Raoultella planticola) were analyzed: 20 cases of biliary tract infection, 5 cases of liver infection, and 4 cases of peritonitis. Fever and abdominal pain were the main symptoms, and some patients present with multiple skin flushes, systemic erythema. Of the 40 cases, 92.5% of patients had underlying diseases. Among them, malignant disease, immunodeficiency, and invasive operations increase the risk of infection. On the basis of the drug susceptibility results, the preferred antibiotics are quinolone, third generations of cephalosporins, carbapenems, and aminoglycoside. Last, patients with abdominal infections caused by Raoultella spp. mostly have a good prognosis after early use of sensitive antibiotics. Conclusions: According to existing literature reports, the main type of abdominal infection caused by Raoultella is biliary tract infection, and most patients have other underlying diseases. Malignancy, immune deficiency, and invasive procedures are risk factors for bacterial infections. This review also emphasizes that Raoultella spp. is a rarely found opportunistic pathogen, which can cause a high incidence of healthcare-associated infections after invasive procedures.

Raoultella planticola Pneumonia: A Rare Causative Organism

We present a case of Raoultella planticola (R. planticola) infection that resulted in community-acquired pneumonia in an immunocompetent patient with an eight-week history of productive cough. This gram-negative bacterium is typically found in the environment and has the potential to infect humans. Raoultella planticola infections in humans have been recorded in several case reports from throughout the world in recent years, usually affecting immunocompromised patients. Although R. planticola is sensitive to most antibiotic groups, recent studies have revealed an increase in the infrequent acquisition of resistance genes in R. planticola, such as carbapenem resistance, making this pathogen a potential emergent threat. Our patient acquired R. planticola pneumonia in the absence of any underlying risk factors, making this the first case in the UK of R. planticola causing community-acquired pneumonia in an immunocompetent person.

Acute cholecystitis secondary to Raoultella ornithinolytica infection, complicated by sepsis, gallbladder perforation, hepatic abscess and bacteraemia

Herein, a case of an immunocompromised patient in his early 70s is discussed who presented with clinical signs and symptoms compatible with sepsis from an intra-abdominal source and who was found to have blood cultures positive for the encapsulated Gram-negative pathogen Raoultella ornithinolytica, with the source of infection determined, via imaging, to be a case of acute cholecystitis complicated by gallbladder perforation, multiple pericholecystic and hepatic abscesses, and persistent bacteraemia. To our knowledge, this represents the first described case of cholecystitis and gallbladder perforation directly attributed to this species, and highlights both the pathogen's capacity to cause severe disease as well as the utility of a multidisciplinary approach to achieve optimal patient outcome.

Isolation of Raoultella ornithinolytica in a HIV positive patient with a lung abscess

A 38 year old male HIV positive patient with a history of intravenous drug use presented with chest pains, cough, sputum and weight loss and radiology demonstrated the evolution of a right basal lung abscess. A lung biopsy sent for 16S rRNA analysis and sputum cultured about the same time demonstrated Raoultella ornithinolytica . No other causative pathogens were clearly identified. He gradually improved with a 4 week course of intravenous cefazolin. R. ornithinolytica is a rare, but recognised pathogen.

Case Study: Soft Tissue Infection with Raoultella ornithinolytica

Raoultella ornithinolytica is a rare encapsulated Gram-negative aerobic and facultative anaerobic rod belonging to the Enterobacteriaceae family. It tends to inhabit water and soil environments and can be found on insects, fish, ticks, and termites, but can also found in the hospital environment.^1,2R ornithinolytica has been documented in respiratory, urinary, gastrointestinal, and biliary tract infections as well as bacteraemia and systemic infections but has rarely been documented in soft tissue infections.² This case study describes a recurrent paronychia infection secondary to R ornithinolytica in a young woman not responding to antibiotics and successfully treated with surgical management.

Decreased susceptibility to imipenem and ceftazidime in early virulent Raoultella spp. strains retrieved from human intestinal infections

The genus Raoultella spp. is comprised of four species, namely, R. electrica, R. ornithinolytica, R. planticola, and R. terrigena, which are rarely reported to cause infections in humans. This study aimed to characterize six strains of Raoultella spp. isolated from stool samples from patients with diarrhea. The strains included in the study were previously identified by biochemical methods as K. pneumoniae, during a surveillance study conducted in 1987. In the present study, the strains were re-identified by MALDI TOF and 16S rRNA sequencing and subsequently subjected to virulence gene screening by PCR, hemolytic activity, biofilm formation, hypermucoviscosity phenotype, capacity to interact with Caco-2 cells, and antimicrobial susceptibility test. Our results revealed that, among the six strains, three were identified as R. ornithinolytica and three as R. planticola. The genes related to iron uptake systems (aero1, aero2, iutA, entB, and ybtS) and adhesin (mrkD) were found in all strains. Furthermore, all strains demonstrated the ability to interact in vitro with Caco-2 cells and form biofilms. In general, the strains studied were sensitive to the antimicrobials tested; however, it was possible to observe high MICs for imipenem compared to ertapenem and meropenem and high minimal inhibitory concentrations (MICs) for ceftazidime, except for one strain. Our results show the occurrence of virulent strains of Raoultella spp. with high MICs for imipenem and ceftazidime causing diarrhea. We hope that our findings can contribute to the understanding of the evolution of this species since, as far as we know, these are the oldest isolates reported so far.

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.

Neonatal Community-acquired Raoultella Ornithinolytica Septicemia: A Case Report and Review of the Literature

Raoultella ornithinolytica is an opportunistic, aquaphilic and Gram-negative bacterium. Immune deficiency states and indwelling catheters provide a basis for most of the infections arising. R. ornithinolytica septicemia (ROS) is extremely rare in neonates but can be life threatening. Community-acquired ROS has not been described in neonates before. The diagnosis of neonatal septicemia is occasionally complicated by unusual clinical presentations. Pyloric stenosis is manifested by projectile, nonbilious vomiting and late findings, including weight loss, dehydration and electrolyte abnormalities beyond 4-6 weeks old. Community-acquired neonatal septicemia symptoms can sometimes be confused with symptoms of gastrointestinal obstructions in patients without risk factors for sepsis. Early diagnosis and appropriate antibiotics are essentials for a good prognosis in neonatal septicemia. Herein, we present a novel case of community-acquired ROS with an unusual presentation in a term infant and a review of the literature about ROS in the neonatal period.

Microbiological and Clinical Aspects of Raoultella spp

The genus Raoultella was established in 2001. Species of Raoultella and Klebsiella share many ecological, biochemical, clinical, and microbiological features. Given the shortcomings of available technology for species identification in the clinical microbiology laboratory, are practically indistinguishable. Since the late 2000s there has been an increase in case reports of human Raoultella infections. Therefore, several authors are postulating that Raoultella spp. are rare and/or emerging pathogens.

Conclusions:Raoultella spp. are very similar to Klebsiella spp. The epidemiology and the clinical relevance of the human Raoultella spp. infections is uncertain and further studies are required. The previous difficulties in the identification of Raoultella spp. and the introduction of more precise identification techniques may explain the recent increase in the number of case reports. Raoultella spp. might be rather underdiagnosed than rare or emerging pathogens.

Soul of the Jukskei River: The Extent of Bacterial Contamination in the Jukskei River in Gauteng Province, South Africa

River water quality is an important health issue as the water is utilised for drinking, domestic and agricultural use in developing countries. This study aimed to investigate the effect water from a major city has on the water quality of the Jukskei River that daylights in Johannesburg, South Africa. The river water samples were analysed for physio-chemical properties, microbiology, antibiotic resistance of bacterial isolates, genetic markers, and potentially toxic metals. Data analysis revealed increased electrical conductivity, total dissolved solids, and turbidity since 2010. Total Coliform and Escherichia coli detected were above the South African water quality guidelines for domestic, recreational, and irrigation purposes. Additionally, sodium, zinc, nickel, lithium, and lead exceeded the guidelines in domestic, recreational, and irrigation water. Pathogenic strains of E. coli (aEPEC, EHEC, EIEC, and EAEC) were isolated from the water. Various other potentially pathogenic organisms that have been implicated as causes of gastro-intestinal, and a wide range of other diseases, were also detected and demonstrated multiple levels of resistance to antibiotics tested. The results show that the river water is a potential health threat to downstream users. These results will feed into the environmental management action plan for Water for the Future (NGO group).

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.

Clinical and microbiological characteristics of patients with Raoultella spp. isolation in Bogotá, Colombia

INTRODUCTION

Raoultella spp. is a gram-negative bacillus with increasing clinical importance due to the development of multi-drug resistance and because it has been reported as a cause of invasive infection. The risk of infection increases if comorbidities present such as diabetes mellitus and malignancies.

METHODS

Descriptive study of clinical and microbiological characteristics in adult patients with Raoultella spp. isolation, treated at a fourth-level hospital in Bogotá, Colombia, between 2015 and 2020.

RESULTS

61 patients with isolation of Raoultella spp., 51 were considered infection and 10, colonization. The associated comorbidities were hypertension (n=26, 42.6%), heart failure (n=19, 31.1%) and diabetes mellitus (n=18, 29.5%). AmpC resistance patterns were found in 10 samples (16.4%) and KPC in 3 (4.9%).

CONCLUSIONS

Raoultella spp. is of clinical importance due to its isolation in immunocompromised patients with multiple comorbidities and due to the increase in multi-resistant strains.

URINARY STONE RELATED URINARY TRACT INFECTION CAUSED BY RAOULTELLA ORNITHINOLYTICA IN A CHILD: A CASE REPORT

Raoultella ornithinolytica is one of the three species of Raoultella. The present case report describes a two-year-old child who had complaints of discomfort and fever, and Raoultella ornithinolytica in his urinary culture. Grade-2 hydronephrosis and a 7.5-mm urinary stone were detected in the patient’s left ureter. The stone was expelled upon consultation with pediatric urology department. The patient was treated according to culture antibiotic sensitivity report and continued to be followed-up.

Neonatal septicemia caused by a rare pathogen: Raoultella planticola - a report of four cases

Background

Raoultella planticola(R.planticola) is a very rare opportunistic pathogen and sometimes even associated with fatal infection in pediatric cases. Recently,the emergence of carbapenem resistance strains are constantly being reported and a growing source of concern for pediatricians.

Case presentation

We reported 4 cases of neonatal septicemia caused by Raoultella planticola. Their gestational age was 211 to 269 days, and their birth weight was 1490 to 3000 g.The R. planticola infections were detected on the 9th to 27th day after hospitalization and occured between May and June. They clinically manifested as poor mental response, recurrent cyanosis, apnea, decreased heart rate and blood oxygen, recurrent jaundice, fever or nonelevation of body temperature. The C-reactive protein and procalcitonin were elevated at significantly in the initial phase of the infection,and they had leukocytosis or leukopenia. Prior to R.planticola infection,all of them recevied at least one broad-spectrum antibiotic for 7-27d.All the R.planticola strains detected were only sensitive to amikacin, but resistant to other groups of drugs: cephalosporins (such as cefazolin, ceftetan,etc) and penicillins (such as ampicillin-sulbactam,piperacillin,etc),and even developed resistance to carbapenem. All the infants were clinically cured and discharged with overall good prognosis.

Conclusion

Neonatal septicemia caused by Raoultella planticola mostly occured in hot and humid summer, which lack specific clinical manifestations. Pediatricians should keep in mind that R. planticola can be a potential source of neonatal sepsis and even has the potential to acquire carbapenem-resistance. Preventing outbreaks of epidemics requires early detection, timely diagnosis and treatment, and active isolation.

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.

Raoultella ornithinolytica: Emergence and Resistance

Raoultella ornithinolytica is an encapsulated Gram-negative, oxidase-negative, catalase-positive, aerobic, non-motile rod that belongs to the Enterobacteriaceae family. This bacterium was initially classified in the genus Klebsiella as Klebsiella ornithinolytica, until the creation of the genus Raoultella in 2001. R. ornithinolytica is usually found in water environments and soil, and due to its ability to convert histidine to histamine, it has been associated with histamine poisoning in humans. R. ornithinolytica is an emerging entity in human infections, with several reports of virulent infections in comorbid at-risk patients. Increasing reports are potentially due to better and more precise identification tools. The objective of this article is to provide a comprehensive review of reported cases of R. ornithinolytica infections, the emergent virulence of described multiresistant strains, and an overview of currently used identification methods.

Unusual Localization of an Emergent Bacterium, Raoultella ornithinolytica

Raoultella ornithinolytica is a bacterium belonging to the family Enterobacteriacae. It is a rare but emergent cause of human pathologies especially in immunocompromised patients. We described the first case in the literature of isolated external otitis sustained by Raoultella ornithinolytica in an immunocompetent host. A 54-year-old Caucasian man with a history of previous myringoplasty came to our attention reporting otalgia and otorrhea. We performed right ear swab for culture examination, meanwhile we started empirical therapy with topic administration of neomycin, without any clinical improvement. The cultural examination showed the presence of a Raoultella ornithinolytica infection. After ten days of treatment with oral ciprofloxacin and topic levofloxacin, there was the complete resolution of pain and inflammation. Raoultella ornithinolytica must be taken into consideration as an emergent cause of human infection, also in case of external otitis. Infection can be severe and can occur both in immunocompromised and in immunocompetent hosts. Culture test is mandatory to choose the proper therapy and avoid potential severe complications.

Recurrent urinary tract infections caused by Raoultella planticola after kidney transplant

Recurrent urinary tract infections are difficult to manage in patients with a history of kidney transplant and may contribute to graft loss. Few cases describe recurrent urinary tract infections due to Raoultella planticola in this population. We describe the management of recurrent urinary tract infections due to R planticola in a kidney transplant recipient and review other case reports of urinary tract infections due to this organism.

Raoultella planticola associated with Meckel's diverticulum perforation and peritonitis in a child: Case report and systematic review of the paediatric literature

Raoultella planticola (R. planticola) is a Gram-negative, aerobic, rod bacteria found in water and soil that has been on rare occasions associated with clinical infections. However, in recent years, there has been both an increase in the frequency and severity of R. planticola infections. We present the first case of Meckel's diverticulum perforation and peritonitis in a child associated with R. planticola infection and a systematic review of the paediatric literature. At present, in the paediatric population, R. planticola presents good susceptibility to a variety of antibiotics with the exception of ampicillin.

Comparative genomics reveals diverse capsular polysaccharide synthesis gene clusters in emerging Raoultella planticola

Raoultella planticola is an emerging zoonotic pathogen that is associated with rare but life-threatening cases of bacteremia, biliary tract infections, and urinary tract infections. Moreover, increasing antimicrobial resistance in the organism poses a potential threat to public health. In spite of its importance as a human pathogen, the genome of R. planticola remains largely unexplored and little is known about its virulence factors. Although lipopolysaccharides has been detected in R. planticola and implicated in the virulence in earlier studies, the genetic background is unknown. Here, we report the complete genome and comparative analysis of the multidrug-resistant clinical isolate R. planticola GODA. The complete genome sequence of R. planticola GODA was sequenced using single-molecule real-time DNA sequencing. Comparative genomic analysis reveals distinct capsular polysaccharide synthesis gene clusters in R. planticola GODA. In addition, we found bla_TEM-57 and multiple transporters related to multidrug resistance. The availability of genomic data in open databases of this emerging zoonotic pathogen, in tandem with our comparative study, provides better understanding of R. planticola and the basis for future work.

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.

Ventilator associated pneumonia caused by Raoultella ornithinolytica in two immunocompetent trauma patients

Infections with Raoultella ornithinolytica have recently been reported more frequently in the medical literature. This pathogen has the potential to cause many types of infections, including pneumonia. Here, we report the first two cases of ventilator-associated pneumonia (VAP) in trauma patients caused by Raoultella ornithinolytica. Both of these infections were successfully treated with antibiotics based on susceptibilities and the patients were able to be transferred out of the intensive care unit.

The first case of Raoultella planticola infective endocarditis in a 4 year old child: A case report and review of literature

Infective endocarditis is a complication of bacteremia that can lead to serious morbidity and even mortality if not appropriately treated, well known organisms commonly lead to this condition in many repeated scenarios so they are usually recognized and treated, but if it was caused by other organisms its detection and treatment can be harder. Raoultella planticola, a low virulent organism used to be part of the Klebsiella species, has been found in many reports to cause multiple human conditions. In this article, a novel case of R. planticola is reported, and the organism was reviewed in many aspects for clinician to be able to recognize this infection and manage it in a more effective way.

Transformation of the Anticancer Drug Doxorubicin in the Human Gut Microbiome

Bacteria living in the human gut are implicated in the etiology of several diseases. Moreover, dozens of drugs are metabolized by elements of the gut microbiome, which may have further implications for human health. Here, we screened a collection of gut isolates for their ability to inactivate the widely used antineoplastic drug doxorubicin and identified a strain of Raoultella planticola as a potent inactivator under anaerobic conditions. We demonstrate that R. planticola deglycosylates doxorubicin to metabolites 7-deoxydoxorubicinol and 7-deoxydoxorubicinolone via a reductive deglycosylation mechanism. We further show that doxorubicin is degraded anaerobically by Klebsiella pneumoniae and Escherichia coli BW25113 and present evidence that this phenotype is dependent on molybdopterin-dependent enzyme(s). Deglycosylation of doxorubicin by R. planticola under anaerobic conditions is found to reduce toxicity to the model species Caenorhabditis elegans, providing a model to begin understanding the role of doxorubicin metabolism by microbes in the human gut. Understanding the in vivo metabolism of important therapeutics like doxorubicin by the gut microbiome has the potential to guide clinical dosing to maximize therapeutic benefit while limiting undesirable side effects.

Raoultella Ornithinolytica Diagnosed in a Neurointensive Patient. A Rare Case with Recovery without Antibiotics

Infection with Raoultella ornithinolytica is rare and normally the infection is present in patients with underlying malignancies or chronic diseases. It is normally treated with antibiotics. In this case report, a neuro-intensive patient without malignancies or other severe chronic diseases was colonized with Pseudomonas aeruginosa but infected with Raoultella ornithinolyca. The patient recovered without treatment with antibiotics.

A novel case of Raoultella planticola osteomyelitis and epidural abscess

A spinal epidural abscess is the collection of pus in the epidural space, and is a potentially life-threatening condition that requires early detection and prompt management. Almost two-thirds of cases are caused by Staphylococcus aureus, followed by Gram-negative bacilli which account for approximately 16% of cases. Raoultella planticola is an emerging pathogen, and is an extremely rare cause of invasive infection in humans. It has been reported to cause urinary tract infections, pneumonia, bacteraemia, cholangitis, cholecystitis, conjunctivitis and soft tissue infections. We report the first case, to our knowledge, of R. planticola osteomyelitis and spinal epidural abscess.

A case of Raoultella planticola causing a urinary tract infection in a pediatric patient

Raoultella planticola (R. planticola) is an abundant environmental bacterium that rarely infects humans. There is only one known case of R. planticola causing a urinary tract infection (UTI) in a pediatric patient. This is a second case of R. planticola potentially causing a symptomatic UTI in a 2-month-old female child with no known medical problems.

Joint infection due to Raoultella planticola: first report

The genus Raoultella has been separated from the genus Klebsiella in 2001. Two main species are responsible for human infections: R. ornithinolytica and R. planticola. The most frequent infections due to R. planticola include cystitis, pneumonia and bacteremia (mostly in immunocompromised hosts). To date, no joint or bone infection has been reported. We describe the first case of septic arthritis due to R. planticola following an arthroscopy with intra-articular injection of corticosteroids. Evolution was favorable after arthroscopic lavage and antibiotic therapy with quinolones. Raoultella planticola has been described rarely in human infection. It is mainly deemed responsible for cystitis, pneumonia and bacteremia (mostly in immunocompromised hosts) [1-3]. To our knowledge no case of bone or joint infection has been reported. We described here the first case of infective arthritis due to R. planticola involving a native knee joint following synovectomy and intra-articular injection of corticosteroids during arthroscopy.

A case of urinary tract infection caused by Raoultella planticola after a urodynamic study

Here we report the case of a patient who developed urinary tract infection after a urodynamic study. The causative agent was Raoultella planticola, a rare opportunistic pathogen that usually invades immunocompromised patients. While a urinary tract infection with R. planticola has been previously described, this is the first report in which an R. planticola infection developed after a urodynamic study. We postulate that the mechanism of infection was direct invasion of the urinary tract from contaminated urodynamic study equipment. Here, we discuss the role played by isotonic solutions in facilitating bacterial reproduction.

Emerging role of Raoultella ornithinolytica in human infections: a series of cases and review of the literature

BACKGROUND

Raoultella ornithinolytica is known to inhabit aquatic environments. The clinical features and outcomes of human infections caused by R. ornithinolytica have been reported for only a limited number of cases.

METHODS

A retrospective study of cases of infection caused by R. ornithinolytica managed at four university hospital centres during the period before and after the introduction of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was performed. The aim was to describe the clinical and microbiological characteristics, treatments, and outcomes.

RESULTS

Among 187 R. ornithinolytica isolates identified for which clinical information was available, 71 were considered colonizers and 116 were pathogenic. A total of 112 cases of R. ornithinolytica infection were identified. Urinary tract infections, gastrointestinal infections, wound and skin infections, and bacteraemia were observed in 36%, 14%, 13%, and 5% of cases, respectively. Associated infections that have been poorly reported, such as respiratory infections, i.e. pneumonia and pleural effusion, were observed in 24% of cases. Additional diseases reported here for the first time included osteomyelitis, meningitis, cerebral abscess, mediastinitis, pericarditis, conjunctivitis, and otitis. The proportion of R. ornithinolytica isolates resistant to antibiotics was found to be relatively high: 4% of isolates were resistant to ceftriaxone, 6% to quinolones, and 13% to co-trimoxazole. The mortality rate related to infection was 5%.

CONCLUSIONS

R. ornithinolytica is an underreported, emerging hospital-acquired infection and is particularly associated with invasive procedures. R. ornithinolytica should never be considered simply a saprophytic bacterium that occasionally contaminates bronchial lavage or other deep respiratory samples or surgical sites. Physicians should be aware of the high rates of antimicrobial resistance of R. ornithinolytica isolates so that immediate broad-spectrum antibiotic treatment can be established before accurate microbiological results are obtained.