Pseudomonas mendocina as a cause of chronic infective endocarditis in a patient with situs inversus

Bacteria of Zoonotic Interest Identified on Edible Freshwater Fish Imported to Australia

Previous research has shown that freshwater edible fish imported into Australia are not compliant with Australian importation guidelines and as a result may be high risk for bacterial contamination. In the present study, the outer surface of imported freshwater fish were swabbed, cultured, confirmatory tests performed and antimicrobial patterns investigated. Channidae fish (Sp. A/n = 66) were contaminated with zoonotic Salmonella sp./Staphylococcus aureus (n = 1/66) and other bacteria implicated in cases of opportunistic human infection, these being Pseudomonas sp. (including P. mendocina and P. pseudoalcaligenes (n = 34/66)); Micrococcus sp. (n = 32/66); Comamonas testosteroni (n = 27/66) and Rhizobium radiobacter (n = 3/66). Pangasiidae fish (Species B/n = 47) were contaminated with zoonotic Vibrio fluvialis (n = 10/47); Salmonella sp. (n = 6/47) and environmental bacteria Micrococcus sp. (n = 3/47). One sample was resistant to all antimicrobials tested and is considered to be Methicillin Resistant S. aureus. Mud, natural diet, or vegetation identified in Sp. A fish/or packaging were significantly associated with the presence of Pseudomonas spp. The study also showed that visibly clean fish (Sp. B) may harbour zoonotic bacteria and that certain types of bacteria are common to fish groups, preparations, and contaminants. Further investigations are required to support the development of appropriate food safety recommendations in Australia.

Pseudomonas mendocina Urinary Tract Infection: A Case Report and Literature Review

Pseudomonas mendocina is a Gram-negative bacillus from the family Pseudomonadaceae. The first P. mendocina-related infection was reported in 1992. Although a rare cause of infections, P. mendocina has been known to cause severe infections that require intensive treatment. We present the first documented case of urinary tract infection caused by P. mendocina.

An 83-year-old male with a past medical history of diabetes, hypertension, coronary artery disease, and prostate cancer with bone metastases, currently being treated with abiraterone and prednisone, presented with subjective fever, fatigue, altered mental status, dysuria, and hematuria of one-week duration. He was found to have a complicated urinary tract infection with an incidental asymptomatic COVID-19 infection on admission. The patient was empirically treated with ceftriaxone and switched to cefepime for broader coverage on day two of hospitalization. Urine culture reported the presence of P. mendocina with resistance only to fluoroquinolones. Ceftriaxone was reinstated. The patient was successfully treated with a seven-day course of ceftriaxone (days 1-3, days 6-7) and cefepime (days 4-5) but continued to remain inpatient for a later symptomatic COVID-19 pneumonia with discharge on day 15.

The majority of P. mendocina infections present as skin and soft tissue infections, infective endocarditis, meningitis, and bacteremia. Ours is the first documented case of urinary tract infection caused by P. mendocina, particularly in an immunocompromised COVID-19 patient, and the second to report P. mendocina with resistance to fluoroquinolones. This report contributes to the growing literature regarding P. mendocina-related infections.

A Case of Pseudomonas mendocina Bacteremia in an Elderly Man With Bilateral Leg Lesions

Pseudomonas mendocina is a gram-negative, aerobic, rod-shaped bacterium that rarely causes disease in humans. Documented infections can be severe with varying etiologies, often requiring intensive care. We describe a rare case of bacteremia with P. mendocina in an elderly male, with a comprehensive review of the literature.

An 81-year-old Caucasian male presented with bilateral lower leg erythema and drainage but was afebrile. His past medical history included atrial fibrillation, chronic kidney disease, and congestive heart failure. Labs showed leukocytosis and a blood culture was obtained revealing Pseudomonas mendocina. The pathogen was susceptible to all antibiotics tested and he was successfully treated on cefepime inpatient and a two-week course of ciprofloxacin on discharge.

Our case and literature review presents a successful treatment of a rare cause of bacteremia likely stemming from a soft tissue nidus. P. mendocina has a favorable susceptibility profile and the antibiotics preferred differ from Pseudomonas aeruginosa, a more common pathogen. Worldwide there have been only 18 other documented cases of P. mendocina infection, all successful and with no mortality. Physicians can confidently utilize usual antibiotics in the treatment of this pathogen despite its rare clinical manifestations.

Pseudomonas Mendocina Bacteremia in a Hemodialysis Patient With a Central Venous Catheter

Pseudomonas mendocina is an uncommon pathogen in humans and there are no documented cases of infection associated with central venous catheters. Here we describe a 72-year-old man on hemodialysis who presented with a fever and was found to have P. mendocina bacteremia. The only obvious source of infection was the hemodialysis catheter. The isolate was susceptible to all antibiotics tested and he was successfully treated with ciprofloxacin and central venous catheter removal. Patients with chronic medical conditions and vascular devices are at risk for invasive infections with rare Pseudomonas species. As laboratory pathogen detection advances arise, it is possible that additional cases of Pseudomonas mendocina infections in humans will be identified. Our case provides one example of the successful treatment of Pseudomonas mendocina bacteremia in a 72-year-old man with a line-associated infection.

Gut microbiota response to ionizing radiation and its modulation by HDAC inhibitor TSA

AIM

Trichostatin A (TSA) has been shown to mitigate whole body γ-radiation-induced morbidity and mortality. The current study aimed at studying the effects of TSA post-irradiation treatment on gut-microbiota, especially the translocation of the microbes from the intestine to other organs in C57 Bl/6 mice model.

MATERIALS AND METHODS

On 1st, 3rd 5th 7th 9th 12th and 14th days after various treatments bacteria were isolated from the intestine and nearby organs (mesenteric lymph node, spleen and liver) for further analysis. The jejunum part of all animals was processed for histological analysis.

RESULTS

The group radiation + drug showed reduced susceptibility to radiation injury as well as microbiota related anomalies compared to the irradiated alone group. This was described by increased microflora in different parts of the GI tract in the radiation + drug group compared to the irradiated group and reduced histopathological damages in the jejunum. Also, a reduced percentage of translocated bacteria were found in different organs of radiation + drug group animals.

CONCLUSION

TSA treatment post-irradiation could effectively control bacterial translocation as well as GI injury in mice.

A Systematic Review of Human Infections by Pseudomonas mendocina

Pseudomonas mendocina is a Gram-negative, rod-shaped, aerobic bacterium that belongs in the family Pseudomonadaceae and has been isolated from water and soil. Even though it is thought to cause infections quite rarely in humans, it can cause severe infections even in immunocompetent individuals. The aim of this study was to systemically review all cases of human infection by P. mendocina in the literature and describe their epidemiology, microbiology, antimicrobial susceptibility, treatment and outcomes. Thus, a systematic review of PubMed for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of Pseudomonas mendocina infections was conducted. In total, 12 studies, containing data of 16 patients, were included. The commonest P. mendocina infections were infective endocarditis, central nervous system infections and skin and soft tissue infections (SSTIs). Fever was the main presenting symptom, while sepsis was evident in almost half the patients. Pseudomonas mendocina was susceptible to most antibiotics tested. Mortality was low in all different infection types. Third or fourth generation cephalosporins and quinolones are the commonest agents used for treatment, irrespectively of the infection site.

Pseudomonas Mendocina Bacteremia: A Case Study and Review of Literature

Patient: Male, 64

Final Diagnosis: Pseudomonas mendocina bacteremia

Symptoms: Encephalopathy • fever • hypotension • rigors • tachypnea

Medication: —

Clinical Procedure: —

Specialty: Infectious Diseases

Identification and characterisation of short chain rhamnolipid production in a previously uninvestigated, non-pathogenic marine pseudomonad

This study aimed to identify and characterise biosurfactant compounds produced by bacteria associated with a marine eukaryotic phytoplankton bloom. One strain, designated MCTG214(3b1), was isolated by enrichment with polycyclic aromatic hydrocarbons and based on 16S rDNA, and gyrB sequencing was found to belong to the genus Pseudomonas, however not related to P. aeruginosa. Cell-free supernatant samples of strain MCTG214(3b1) at stationary phase showed significant reductions in surface tension. HPLC-MS and NMR analysis of these samples indicated the presence of five different rhamnolipid (RL) congeners. Di-rhamnolipids accounted for 87% relative abundance and all congeners possessed fatty acid moieties consisting of 8–12 carbons. PCR screening of strain MCTG214(3b1) DNA revealed homologues to the P. aeruginosa RL synthesis genes rhlA and rhlB; however, no rhlC homologue was identified. Using the Galleria mellonella larvae model, strain MCTG214(3b1) was demonstrated to be far less pathogenic than P. aeruginosa. This study identifies for the first time a significantly high level of synthesis of short chain di-rhamnolipids by a non-pathogenic marine Pseudomonas species. We postulate that RL synthesis in Pseudomonas sp. MCTG214(3b1) is carried out by enzymes expressed from rhlA/B homologues similar to those of P. aeruginosa; however, a lack of rhlC potentially indicates the presence of a second novel rhamnosyltransferase responsible for the di-rhamnolipid congeners identified by HPLC-MS.

The clinical characteristics of adult bacterial meningitis caused by non-Pseudomonas (Ps.) aeruginosa Pseudomonas species: A clinical comparison with Ps. aeruginosa meningitis

Adult bacterial meningitis (ABM) caused by non-Pseudomonas (Ps.) aeruginosa Pseudomonas (NPAP) species infection has rarely been reported. The clinical characteristics of 52 cases of Pseudomonas ABM (11 NPAP- and 41 Ps. aeruginosa-related meningitis) collected during a 30-year study period (1986-2015) were included. Eleven cases of NPAP ABM were identified in the literature, and their clinical data were also collected. Therefore, a total of 22 NPAP ABM cases were enrolled. The clinical characteristics of the NPAP ABM and Ps. aeruginosa ABM groups were compared. Of the implicated NPAP strains, Ps. putida and Ps. stutzeri were the most common (7 cases each), followed by Ps. mendocina in 4, Ps. fluorescens in 1, Ps. fulva in 1, Ps. alcaligenes in 1, and Ps. mosselii in 1. Of the 22 cases, 50% (11/22) had an underlying postneurosurgical state. Fever (77.3%, 17/22) and altered consciousness (45.5%, 10/22) were the most common clinical presentations. Antibiotic non-susceptibility was found in 3 strains of Ps. putida and 1 Ps. mosselii strain. Compared to the patients with Ps. aeruginosa ABM, those with NPAP ABM had a higher incidence of spontaneous infections and a better survival rate. In conclusion, although Ps. putida, Ps. stutzeri and Ps. mendocina were the major implicated strains of NPAP ABM, the clinical characteristics of this specific group of ABM demonstrated marked heterogeneity. Even though the cases with NPAP ABM had better therapeutic results than those with Ps. aeruginosa ABM, further large-scale studies are needed to better delineate this specific group of ABM.

Pseudomonas mendocina native valve infective endocarditis: a case report

BACKGROUND

Gram-negative microorganisms are uncommon pathogens responsible for infective endocarditis. Pseudomonas mendocina, a Gram-negative water-borne and soil-borne bacterium, was first reported to cause human infection in 1992. Since then, it has rarely been reported as a human pathogen in the literature. We describe the first case of native valve infective endocarditis due to P. mendocina in the USA.

CASE PRESENTATION

A 57-year-old white man presented with bilateral large leg ulcers, fever, and marked leukocytosis. His past medical history included gout and chronic alcohol use. P. mendocina was isolated from his blood cultures. A comprehensive review of P. mendocina infection in the literature was performed. A total of eight cases of P. mendocina infection were reported in the literature. More than two-thirds of the cases of P. mendocina septicemia were associated with native valve infective endocarditis. Thus, an echocardiogram was performed and demonstrated mitral valve endocarditis with mild mitral insufficiency. His leg wounds were debrided and were probably the source of P. mendocina bacteremia. Unlike Pseudomonas aeruginosa, P. mendocina is susceptible to third-generation cephalosporins. Our patient received a 6-week course of antimicrobial therapy with a favorable clinical outcome.

CONCLUSIONS

Our reported case and literature review illuminates a rare bacterial cause of infective endocarditis secondary to P. mendocina pathogen. Native cardiac valves were affected in all reported cases of infective endocarditis, and a majority of affected heart valves were left-sided. The antibiotics active against P. mendocina are different from those that are active against P. aeruginosa, and they notably include third-generation cephalosporins. The outcome of all reported cases of P. mendocina was favorable and no mortality was described.

T cell epitope mimicry between Sjögren's syndrome Antigen A (SSA)/Ro60 and oral, gut, skin and vaginal bacteria

This study was undertaken to test the hypothesis that Sjogren's syndrome Antigen A (SSA)/Ro60-reactive T cells are activated by peptides originating from oral and gut bacteria. T cell hybridomas generated from HLA-DR3 transgenic mice recognized 3 regions on Ro60, with core epitopes mapped to amino acids 228-238, 246-256 and 371-381. BLAST analysis identified several mimicry peptides, originating from human oral, intestinal, skin and vaginal bacteria, as well as environmental bacteria. Amongst these, a peptide from the von Willebrand factor type A domain protein (vWFA) from the oral microbe Capnocytophaga ochracea was the most potent activator. Further, Ro60-reactive T cells were activated by recombinant vWFA protein and whole Escherichia coli expressing this protein. These results demonstrate that peptides derived from normal human microbiota can activate Ro60-reactive T cells. Thus, immune responses to commensal microbiota and opportunistic pathogens should be explored as potential triggers for initiating autoimmunity in SLE and Sjögren's syndrome.

Current diagnosis and treatment of infective endocarditis

The incidence of infective endocarditis continues to rise with a yearly incidence of around 15,000 to 20,000 new cases in the USA. As a result, rapid diagnosis, effective treatment and prompt recognition of complications are essential to desirable clinical outcomes. Recent guidelines such as the Duke criteria have incorporated echocardiography for diagnosis of infective endocarditis, making this diagnostic test mandatory for patients with suspected infective endocarditis. The diversity of pathogens that can cause infective endocarditis, some of which cannot be cultured easily, makes diagnosis even more difficult. Coagulase-negative staphylococci and viridans streptococci groups continue to be the major causative microorganisms of infective endocarditis. In the case of culture-negative endocarditis or infective endocarditis caused by fastidious microorganisms, the polymerase chain reaction and probe-based diagnostic methods are available to clinical reference laboratories.

Native valve endocarditis due to Pseudomonas mendocina in a patient with mental retardation and a review of literature

Pseudomonas mendocina, a Gram-negative non-fermentative rod, occurs in water and soil but is rarely recovered as a human pathogen. We report a native valve endocarditis due to Pseudomonas mendocina in a patient with mental retardation.

Pseudomonas mendocina spondylodiscitis: A case report and literature review

Pseudomonas mendocina is rarely recovered as a human pathogen. Only 2 human cases have been reported in the literature. Here, we report the third human case and possibly the first 1 to involve spinal infection caused by such an unusual bacterium.