Lactococcus garvieae Endocarditis in a Prosthetic Aortic Valve: A Case Report and Literature Review

Infective endocarditis caused by Lactococcus garvieae: A case report and review of the literature

Lactococcus garvieae is a Gram-positive coccus that can be easily misidentified as Enterococcus spp. or streptococci. Infection with L. garvieae is associated with the consumption of raw fish and unpasteurized dairy products. Although rare, it can cause infective endocarditis (IE). Herein, we report a case in which aortic valve replacement (AVR) was required for IE caused by L. garvieae. A 79-year-old Japanese man with a history of hypertension, myocardial infarction, gastroesophageal reflux disease (GERD), and abdominal aortic aneurysm presented with loss of appetite, myalgia, and difficulty in moving. Physical examination revealed a diastolic murmur, an Osler's node on the right first toe, dental caries, and a palpable spleen, suggesting IE. Transthoracic echocardiography revealed a large, mobile vegetation on the aortic valve, which was associated with severe aortic regurgitation. Blood cultures revealed L. garvieae. The patient received antibiotic therapy, underwent AVR, and recovered without major complications. To date, 30 cases of L. garvieae-associated IE have been reported. We reviewed and summarized all cases of L. garvieae-associated IE including our case.

Isolation of Lactic Acid Bacteria (LAB) from Salmonids for Potential Use as Probiotics: In Vitro Assays and Toxicity Assessment of Salmo trutta Embryonated Eggs

This research investigates the potential of lactic acid bacteria (LAB) from freshwater salmonids as prospective probiotics for application in aquaculture. LAB and pathogenic bacteria were obtained from mucus and tissues of Oncorhynchus mykiss and Salmo trutta from fish farms in northeast Spain that had not used antibiotics for the six months preceding the study. Isolates were identified using Gram staining and sequencing of 16S rRNA and ITS-1. To assess the safety of the LAB, antibiotic susceptibility tests (ASTs) against 23 antimicrobials were performed. In vitro antagonism assays were conducted to evaluate the inhibitory effects of living LAB using the agar diffusion test method and their metabolites using the agar well diffusion method. The assays targeted six specific pathogens: Aeromonas salmonicida subsp. salmonicida, Carnobacterium maltaromaticum, Vagococcus salmoninarum, Yersinia ruckeri, Lactococcus garvieae, and the marine pathogen Vibrio jasicida. Additionally, a toxicity assay was conducted on embryonic eggs of S. trutta. The ASTs on probiotic LAB candidates revealed varied responses to antimicrobials, but no resistance to oxytetracycline or florfenicol, which are two antibiotics commonly used in aquaculture, was detected. The in vitro assays indicate that LAB exhibit antagonistic effects against pathogens, primarily when directly stimulated by their presence. In applications involving embryonic eggs or larvae, certain live strains of LAB were found to have adverse effects, with some isolates resulting in higher mortality rates compared to the control group or other isolates. Furthermore, the potential pathogenicity of certain LAB strains, typically considered safe in salmonids, warrants deeper investigation.

Lactococcus garvieae in Rural Alabama: A Case Report

Lactococcus (L.) garvieae is a gram-positive coccus that has been found in various aquatic and terrestrial animals, as well as in dairy products, and is considered a potential zoonotic bacterium. The pathogen has been recognized as an emerging opportunistic human pathogen, often associated with the ingestion of raw seafood. The most common presentation of L. garvieae infection in humans is infective endocarditis, but it has also been found to have associations with other clinical manifestations. The following is a case report of a 6-year-old male with infected bilateral leg abrasions that occurred after playing in a local creek near his home in northern Alabama, which had livestock including goats, cows, and horses. Wound culture indicated that the bacteria was L. garvieae, which was found to be sensitive to ceftriaxone, levofloxacin, linezolid, tetracycline, tigecycline, and vancomycin and resistant to clindamycin. The patient was treated with oral cephalexin and topical gentamicin for ten days, after which there appeared to be an overall improvement in wound healing.

Massive empyema due to Lactococcus garvieae

Introduction

Lactococcus garvieae, a zoonotic pathogen, may rarely infect humans through the consumption of fish. Documented manifestations of L. garvieae infection in humans include infective endocarditis, prosthetic joint infections, liver abscesses, peritoneal dialysis-associated peritonitis, osteomyelitis, meningitis, infective spondylodiscitis, acalculous cholecystitis, and urinary tract infection.

Case report

An 87-year-old female was hospitalized for coffee-ground emesis secondary to acute gastritis after eating cooked fish. One week after her discharge, she developed new-onset confusion and was returned to the hospital. Chest computed tomography revealed total consolidation of the left lung and a multiloculated left pleural effusion. The patient required intubation and direct admission to the intensive care unit. Pleural fluid and blood cultures grew L. garvieae, which was susceptible to ceftriaxone, penicillin, and vancomycin. Despite intensive antibiotic therapy and supportive care for thirteen days, the patient remained in irreversible shock, and the family opted for comfort care.

Conclusions

Heretofore unreported, this case demonstrates that L. garvieae can cause bronchopneumonia and empyema.

Garvicins AG1 and AG2: Two Novel Class IId Bacteriocins of Lactococcus garvieae Lg-Granada

Lactococcus garvieae causes infectious diseases in animals and is considered an emerging zoonotic pathogen involved in human clinical conditions. In silico analysis of plasmid pLG50 of L. garvieae Lg-Granada, an isolate from a patient with endocarditis, revealed the presence of two gene clusters (orf46–47 and orf48–49), each one encoding a novel putative bacteriocin, i.e., garvicin AG1 (GarAG1; orf46) and garvicin AG2 (GarAG2; orf48), and their corresponding immunity proteins (orf47 and orf49). The chemically synthesised bacteriocins GarAG1 and GarAG2 presented inhibitory activity against pathogenic L. garvieae strains, with AG2 also being active against Listeria monocytogenes, Listeria ivanovii and Enterococcus faecalis. Genetic organisation, amino acid sequences and antimicrobial activities of GarAG1 and GarAG2 indicate that they belong to linear non-pediocin-like one-peptide class IId bacteriocins. Gram-positive bacteria that were sensitive to GarAG2 were also able to ferment mannose, suggesting that this bacteriocin could use the mannose phosphotransferase transport system (Man-PTS) involved in mannose uptake as a receptor in sensitive strains. Intriguingly, GarAG1 and GarAG2 were highly active against their own host, L. garvieae Lg-Granada, which could be envisaged as a new strategy to combat pathogens via their own weapons.

Comparative genomics and evolutionary analysis of Lactococcus garvieae isolated from human endocarditis

Lactococcus garvieae is a well-known pathogen of fish, but is rarely involved in infections in humans and other mammals. In humans, the main clinical manifestation of L. garvieae infections is endocarditis usually related to the ingestion of contaminated food, such as undercooked fish and shellfish. This study presents the first complete genomic sequence of a clinical L. garvieae strain isolated from a patient with endocarditis and its comparative analysis with other genomes. This human isolate contains a circular chromosome of 2 099 060 bp and one plasmid of 50 557 bp. In comparison with other fully sequenced L. garvieae strains, the chromosomal DNA of L. garvieae Lg-Granada carries a low proportion of insertion sequence elements and a higher number of putative prophages. Our results show that, in general, L. garvieae is a highly recombinogenic species with an open pangenome in which almost 30 % of its genome has undergone horizontal transfers. Within the genus Lactococcus, L. lactis is the main donor of genetic components to L. garvieae but, taking Lg-Granada as a representative, this bacterium tends to import more genes from Bacilli taxa than from other Lactococcus species.

Assessing the Bacterial Community Composition of Bivalve Mollusks Collected in Aquaculture Farms and Respective Susceptibility to Antibiotics

Aquaculture is a growing sector, providing several products for human consumption, and it is therefore important to guarantee its quality and safety. This study aimed to contribute to the knowledge of bacterial composition of Crassostrea gigas, Mytilus spp. and Ruditapes decussatus, and the antibiotic resistances/resistance genes present in aquaculture environments. Two hundred and twenty-two bacterial strains were recovered from all bivalve mollusks samples belonging to the Aeromonadaceae, Bacillaceae, Comamonadaceae, Enterobacteriaceae, Enterococcaceae, Micrococcaceae, Moraxellaceae, Morganellaceae, Pseudomonadaceae, Shewanellaceae, Staphylococcaceae, Streptococcaceae, Vibrionaceae, and Yersiniaceae families. Decreased susceptibility to oxytetracycline prevails in all bivalve species, aquaculture farms and seasons. Decreased susceptibilities to amoxicillin, amoxicillin/clavulanic acid, cefotaxime, cefoxitin, ceftazidime, chloramphenicol, florfenicol, colistin, ciprofloxacin, flumequine, nalidixic acid and trimethoprim/sulfamethoxazole were also found. This study detected six qnrA genes among Shewanella algae, ten qnrB genes among Citrobacter spp. and Escherichia coli, three oqxAB genes from Raoultella ornithinolytica and bla_TEM-1 in eight E. coli strains harboring a qnrB19 gene. Our results suggest that the bacteria and antibiotic resistances/resistance genes present in bivalve mollusks depend on several factors, such as host species and respective life stage, bacterial family, farm’s location and season, and that is important to study each aquaculture farm individually to implement the most suitable measures to prevent outbreaks.

Lactococcus garvieae: An Uncommon Human Pathogen Causing Infective Endocarditis in a Valve-in-Valve Transcatheter Aortic Valve Replacement

Lactococcus garvieae is a fish pathogen and an uncommon cause of human infections. There is a growing body of evidence showing its potential for causing endocarditis especially in those with prior valve surgery. In this case report, we present what we believe is the first case of endocarditis by L. garvieae affecting a valve-in-valve transcatheter aortic valve replacement that was successfully treated. Specific guidelines for the management of these patients are lacking. Our experience can contribute to the current knowledge regarding this life-threatening infection as well as to the future care of these patients. We aim to emphasize that despite not being recognized as a typical endocarditis microorganism by the Duke Criteria, the possibility of endocarditis needs to be highly entertained in patients with L. garvieae bacteremia, especially when prosthetic valves are present. Consequently, clinicians should pursue further this diagnosis with transesophageal echocardiogram and/or alternative imaging modalities (e.g., PET-CT scan and MRI) regardless of an initial negative transthoracic echocardiogram. Reaching a diagnosis of L. garvieae endocarditis led us to the decision of prolonging the antibiotic course for 6 weeks with successful results. Ultimately, surgery was not required owing to the absence of prosthetic aortic valve dysfunction and paravalvular extension of the infection.