Fatal pancreatic pseudocyst co-infected by Raoultella planticola: an emerging pathogen

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.

The dynamics of the midgut microbiome in Aedes aegypti during digestion reveal putative symbionts

Blood-feeding is crucial for the reproductive cycle of the mosquito Aedes aegypti, as well as for the transmission of arboviruses to hosts. It is postulated that blood meals may influence the mosquito microbiome but shifts in microbial diversity and function during digestion remain elusive. We used whole-genome shotgun metagenomics to monitor the midgut microbiome in 60 individual females of A. aegypti throughout digestion, after 12, 24, and 48 h following blood or sugar meals. Additionally, ten individual larvae were sequenced, showing microbiomes dominated by Microbacterium sp. The high metagenomic coverage allowed for microbial assignments at the species taxonomic level, also providing functional profiling. Females in the post-digestive period and larvae displayed low microbiome diversities. A striking proliferation of Enterobacterales was observed during digestion in blood-fed mosquitoes. The compositional shift was concomitant with enrichment in genes associated with carbohydrate and protein metabolism, as well as virulence factors for antimicrobial resistance and scavenging. The bacterium Elizabethkingia anophelis (Flavobacteriales), a known human pathogen, was the dominant species at the end of blood digestion. Phylogenomics suggests that its association with hematophagous mosquitoes occurred several times. We consider evidence of mutually beneficial host-microbe interactions raised from this association, potentially pivotal for the mosquito's resistance to arbovirus infection. After digestion, the observed shifts in blood-fed females' midguts shifted to a sugar-fed-like microbial profile. This study provides insights into how the microbiome of A. aegypti is modulated to fulfil digestive roles following blood meals, emphasizing proliferation of potential symbionts in response to the dynamic midgut environment.

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.

Ruptured Splenic Artery Pseudoaneurysm Causing Hemorrhage Into a Pancreatic Pseudocyst

ABSTRACT

This case report describes fatal exsanguination due to splenic artery hemorrhage into a pancreatic pseudocyst with cystogastrostomy in a 46-year-old woman. The decedent had a complicated medical history including necrotizing pancreatitis, giant pseudocyst formation after cystogastrostomy procedure, and coiling of a hemorrhagic splenic artery. While hospitalized, she underwent embolization of a ruptured splenic artery pseudoaneurysm. Weeks later, she went into hemorrhagic shock and was ultimately pronounced at the hospital. Doctors suspected an upper gastrointestinal (GI) bleed as the cause of death; however, the patient was too unstable to undergo interventional radiology at the time.At autopsy, the pancreas was hemorrhagic and included a 15 × 15 × 15-cm pseudocyst, which contained a metallic stent from a cystogastrostomy. This case describes a unique co-occurrence of numerous common complications of chronic pancreatitis. There are multiple ways by which pancreatitis can cause upper and lower GI bleeds. In this case, the presence of a cystogastrostomy stent allowed for a ruptured pseudoaneurysm to hemorrhage through the pancreatic pseudocyst and into the stomach and duodenum, mimicking the presentation of a more common upper GI bleed. The pseudocyst then ruptured causing abdominal hemorrhage. The passage of hemorrhage through a cystogastrostomy stent is not described in other literature.

Community-acquired infection to Raoultella ornithinolytica presenting as appendicitis and shock in a healthy individual

Raoultella ornithinolytica and Raoultella planticola are histamine-producing bacteria that are usually found in fish and water. They are associated with scombroid syndrome that presents with vomiting and flushing. A wide range of infections with these germs is reported, but mainly in fragile hospitalized patients with multiple comorbidities. We report the case of a 54-year-old healthy patient who presented with 24-hours abdominal pain, vomiting, flushing and shock. The abdominal examination showed guarding in the right lower quadrant (RLQ), and the abdominal CT scan images showed a thickened terminal ileum and a distended appendix. The patient underwent a surgical exploration revealing a normal terminal ileum but an inflamed appendicular base. Raoultella ornithinolytica was found in blood cultures and in the liquid retrieved from the RLQ. To the best of our knowledge, this is the first report of a severe life-threatening intra-abdominal presentation due to a community-acquired R. ornithinolytica infection.

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.

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.