Lactococcus garvieae is a Gram-positive, catalase-negative, non-spore-forming coccus, typically arranged in pairs or short chains. It belongs to the lactic acid bacteria group and is well known as a major pathogen in fish (lactococcosis).
Fig. Lactococcus garvieae growth on CLED agar of urine culture In humans, it is an emerging opportunistic pathogen, increasingly recognized due to improved identification methods such as MALDI-TOF MS.
Fig. Gram-positive cocci of Lactococcus garvieae in Gram staining of culture at a magnification of 1000X Zoonotic potential, commonly linked to: Consumption of raw or undercooked fish/seafood Occupational exposure (fish handlers, aquaculture workers) Predisposing factors: Immunocompromised state Valvular heart disease Malignancy Diabetes mellitus Reported human infections: Pathogenicity is low to moderate, largely dependent on host susceptibility Specimens Blood, urine, bile, ascitic fluid, wound swab (as clinically indicated) Microscopy
Fig. Gram-positive cocci of Lactococcus garvieae in Gram staining of culture at a magnification of 4000X Culture Characteristics Fig. Again, Lactococcus garvieae grew on CLED agar after repetition of the urine culture Blood agar: small, grayish, non-hemolytic or α-hemolytic colonies Grows at 25–37°C Does not tolerate high salt (helps differentiate from Enterococcus Fig. Gram-positive cocci of Lactococcus garvieae in Gram staining of repeated culture at a magnification of 4000X Biochemical Features Confirmatory Identification MALDI-TOF MS (method of choice)16S rRNA gene sequencing (gold standard) Fig. Lactococcus garvieae antibiogram Generally susceptible to beta-lactam antibiotics Common treatment options: Penicillin Ampicillin Amoxicillin Ceftriaxone Severe infections (e.g., endocarditis): Beta-lactam ± aminoglycoside (based on AST ) Fig. Lactococcus garvieae antimicrobial susceptibility result Antimicrobial susceptibility testing is essential due to variable resistance patterns. Avoid consumption of raw or undercooked fish. Proper food hygiene and cooking practices. Protective measures for aquaculture and fish industry workers. Early identification and treatment in high-risk patients. Strict aseptic techniques in hospitals. Emerging zoonotic opportunistic pathogen. Commonly misidentified without advanced diagnostics. Strong association with fish exposure. An important cause of infective endocarditis. Detection is increasing with MALDI-TOF and molecular tools. https://pmc.ncbi.nlm.nih.gov/articles/PMC7455392 https://en.wikipedia.org/wiki/Lactococcus_garvieae https://www.mdpi.com/2076-0817/13/1/49 https://www.sciencedirect.com/topics/immunology-and-microbiology/lactococcus-garvieae https://www.researchgate.net/publication/275330542_Lactococcus_garvieae_a_small_bacteria_and_a_big_data_world https://pmc.ncbi.nlm.nih.gov/articles/PMC8289619 https://onlinelibrary.wiley.com/doi/10.1111/j.1742-1241.2006.00855 https://www.researchgate.net/publication/311088571_Lactococcus_garvieae_An_emerging_bacterial_pathogen_of_fish https://www.cureus.com/articles/331535-urinary-tract-infection-caused-by-lactococcus-garvieae-in-a-75-year-old-male-patient-with-a-complex-medical-history https://www.mdpi.com/2076-2615/10/9/1609