The first case report of Raoultella planticola liver abscess

Abdominal abscess caused by Raoultella ornithinolytica secondary to postoperative gastric fistula: case report and review of literature

BACKGROUND

In recent years, Raoultella ornithinolytica (R. ornithinolytica) have attracted clinical attention as a new type of pathogen. A wide range of infections with these germs is reported, and commonly found in urinary tract infections, respiratory infections, and bacteremia.

CASE PRESENTATION

We report the case of an elderly woman with liver abscess, choledocholithiasis and cholangitis, who developed gastric fistula and abdominal abscess after underwent choledocholithotomy, and R. ornithinolytica were isolated from the abdominal drainage fluid. The patient was treated with meropenem and levofloxacin and had a good outcome.

CONCLUSIONS

To the best of our knowledge, case of isolating R. ornithinolytica from a patient with non-viscerally abdominal abscess was extremely rare. We share a case of a woman with non-viscerally abdominal abscess secondary to postoperative gastric fistula, R. ornithinolytica was isolated from the patient's pus, and the pathogenic bacteria may originate from the gastrointestinal tract. Based on this case, We should be cautious that invasive treatment may greatly increase the probability of infection with this pathogenic bacterium.

Characterization of Antibiotic Resistant Coliform Bacteria and Resistance Genes Isolated from Samples of Smoothie Drinks and Raw Milk

Raw foodstuffs have been marked as a healthier alternative in the context of nutrient content and are becoming more popular with consumers. Thermally untreated foods may represent a microbiological risk connected with the possible presence of antimicrobial resistance. The aim of this study was to prove that popular raw food beverages such as smoothies and raw milk may be a source of antibiotic-resistant coliform bacteria and resistant genes. The majority of antibiotic-resistant isolates (110) were identified as Enterobacter spp., Escherichia coli, and species of Klebsiella spp., predominantly β-lactam and chloramphenicol resistant. Multidrug resistance has been registered in one-third of resistants. Overproduction of efflux pumps was clarified in 8 different bacteria. The majority of resistant isolates were strong biofilm producers. Antibiotic resistance gene blaOXA was detected in 25% of isolates, especially in E. coli. Resistance genes blaTEM and blaSHV were detected in 19% and 14%, respectively. This is the first study to point out that popular raw drinks such as smoothies or raw milk, besides their nutrient benefits, could represent a reservoir of antibiotic-resistant bacteria as well as antibiotic resistance genes. According to this, raw drinks could contribute to the dissemination of antibiotic resistance in the human gastrointestinal tract and environment.

Genetic and virulence characteristics of a Raoultella planticola isolate resistant to carbapenem and tigecycline

Raoultella planticola is an emerging pathogen causing several infections in humans, and its roles in the propagation of antibiotic resistance genes (ARGs) remain uncharacterized. In this study, a carbapenem and tigecycline-resistant R. planticola isolate was recovered from hospital sewage. It carried nine plasmids, bearing 30 ARGs, including one bla_KPC-2 and two bla_NDM-1. It also contained a plasmid-borne efflux pump gene cluster, tmexCD1-toprJ, conferring resistance to tigecycline. Analysis of plasmid sequences revealed that both bla_NDM-1-carrying plasmids were highly similar to those recovered from humans, reinforcing the close relatedness of environmental and clinical isolates. We also identified that plasmid bearing bla_NDM-1 or tmexCD1-toprJ1 was transferable, and can be stabilized in the host bacteria, indicating that the R. planticola isolate has a considerable potential in the dissemination of ARGs. Besides, we found that this isolate could produce biofilm and was virulent in a Galleria mellonella infection model. In conclusion, our study shows the convergence of virulence and multidrug resistance in a R. planticola isolate. This potentially virulent superbug may disseminate into its receiving rivers, and finally to humans through cross-contamination during recreation activities or daily use of water, which poses a risk to public health.

Microbiota identified from preserved Anopheles

Background

Mosquito species from the Anopheles gambiae complex and the Anopheles funestus group are dominant African malaria vectors. Mosquito microbiota play vital roles in physiology and vector competence. Recent research has focused on investigating the mosquito microbiota, especially in wild populations. Wild mosquitoes are preserved and transported to a laboratory for analyses. Thus far, microbial characterization post-preservation has been investigated in only Aedes vexans and Culex pipiens. Investigating the efficacy of cost-effective preservatives has also been limited to AllProtect reagent, ethanol and nucleic acid preservation buffer. This study characterized the microbiota of African Anopheles vectors: Anopheles arabiensis (member of the An. gambiae complex) and An. funestus (member of the An. funestus group), preserved on silica desiccant and RNAlater^® solution.

Methods

Microbial composition and diversity were characterized using culture-dependent (midgut dissections, culturomics, MALDI-TOF MS) and culture-independent techniques (abdominal dissections, DNA extraction, next-generation sequencing) from laboratory (colonized) and field-collected mosquitoes. Colonized mosquitoes were either fresh (non-preserved) or preserved for 4 and 12 weeks on silica or in RNAlater^®. Microbiota were also characterized from field-collected An. arabiensis preserved on silica for 8, 12 and 16 weeks.

Results

Elizabethkingia anophelis and Serratia oryzae were common between both vector species, while Enterobacter cloacae and Staphylococcus epidermidis were specific to females and males, respectively. Microbial diversity was not influenced by sex, condition (fresh or preserved), preservative, or preservation time-period; however, the type of bacterial identification technique affected all microbial diversity indices.

Conclusions

This study broadly characterized the microbiota of An. arabiensis and An. funestus. Silica- and RNAlater^®-preservation were appropriate when paired with culture-dependent and culture-independent techniques, respectively. These results broaden the selection of cost-effective methods available for handling vector samples for downstream microbial analyses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-03754-7.

A novel case of Raoultella bacteremia secondary to liver abscess formation following transarterial chemoembolization

Raoultella planticola is an uncommon gram-negative bacterium that has rarely been identified as the causative organism in severe infections. Few cases have been described and have included patients with pneumonia, urinary tract infections or cholangitis. Only one case has reported to involve a liver abscess, thought to be from a primary urologic source. We describe the case of a 73-year-old man with recently diagnosed hepatocellular carcinoma who developed multiple pyogenic liver abscesses. The abscesses were thought to have developed in the setting of recent transarterial chemoembolization leading to R. planticola bacteremia noted on admission. Treatment with ceftriaxone and metronidazole was initiated in addition to drainage of the abscesses, resulting in decreased size of liver collections and initial clinical improvement. R. planticola remains a rare infectious organism in severe infections affecting both immunocompromised and immunocompetent individuals. Our patient’s underlying malignancy and recent transarterial chemoembolization likely placed him at risk of liver abscess formation complicated by bacteremia and sepsis.

Clinical characteristics and treatment outcomes of patients with pneumonia caused by Raoultella planticola

Background

Raoultella planticola, considered to be an environmental organism, is a rare cause of human infections. Although in recent years the frequency of R. planticola infections reported in the literature has increased, few cases of pneumonia caused by R. planticola have been described. Here, we investigate the clinical characteristics, management, and clinical outcomes of pneumonia caused by R. planticola.

Methods

Consecutive patients with pneumonia caused by R. planticola were included. The medical records of patients with R. planticola pneumonia treated at Dankook University Hospital from January 2011 to December 2017 were collected.

Results

A total of 11 adult patients with R. planticola pneumonia were diagnosed and treated [10 males and 1 female; median age, 70 years (range: 51-79 years)]; 5 patients had underlying malignant conditions (45.5%). Antibacterial susceptibility testing showed that all isolates of R. planticola were susceptible to cephalosporins, carbapenems, fluoroquinolones, aminoglycosides, and beta-lactams/beta-lactamase inhibitors. Chest imaging revealed consolidation (8/11, 72.7%), ground-glass opacity (5/11, 45.5%), pleural effusion (5/11, 45.5%), and micronodules (3/11, 27.3%). Four patients (36.4%) required mechanical ventilation; three survived but one died of multiple organ dysfunction syndrome (principally pneumonia and septic shock).

Conclusions

R. planticola pneumonia occurred mainly in patients with underlying risk factors such as malignant disease, cerebral infarction or hemorrhage, and chronic obstructive pulmonary disease. The organism was sensitive to most antibiotics, and the clinical outcomes were favorable after empirical antibiotic therapy.

Raoultella ornithinolytica and Klebsiella oxytoca pyogenic liver abscess presenting as chronic cough

Raoultella ornithinolytica is a Gram-negative rod belonging to the Enterobacteriaceae family and closely related to Klebsiella spp. It is commonly present in aquatic environments. Human infections caused by R. ornithinolytica are being increasingly recognized. It has been documented to cause various hospital-acquired infections including but not limited to gastrointestinal, skin, and genitourinary infections. The organism has been particularly associated with invasive procedures and is commonly seen in patients with malignancy, diabetes, chronic kidney disease and immunodeficiency. To our knowledge, we report the first case of pyogenic liver abscess caused by this organism. The patient presented subtly with a chronic, nonresolving cough and was managed successfully by surgical drainage and appropriate antimicrobials.

Raoultella planticola Bacteremia in a Patient with Early Gastric Cancer

The patient was an 81-year-old man who was found to have bacteremia due to Raoultella planticola, which might have entered the circulation through the bile duct during the passing of a gallbladder stone. In the present case, we screened for malignancies because most cases of R. planticola bacteremia occur after trauma, invasive procedures, or in patients with malignancy (70.6%). Early gastric cancer was detected. Although the association between R. planticola bacteremia and malignancy remains speculative in the present case, it may be useful to scrutinize similar cases involving low-virulence bacteremia for possible malignancies or immune conditions.

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.

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 Rare Case of Raoultella planticola Pneumonia: An Emerging Pathogen

Raoultella planticola (R. planticola), considered an environmental organism, is a gram negative, motile, bacillus with phenotypic similarities to the genus Klebsiella. The organism remains a rare cause of human infection with a few cases reported in the literature. However, since its description in 1981 there have been increasing rates of infections caused by R. planticola with reports of conjunctivitis, liver abscess, cholangitis, pancreatitis, and necrotizing fasciitis. More concerning are reports of carbapenemase-producing isolates which have led to the only 2 mortalities associated with R. planticola infections. To our knowledge, we report the third case of R. planticola pneumonia in an immunocompromised patient with no known direct exposure to the reported risk factors.