Isolation of Histamine Producing Bacteria (Escherichia coli) from Tiger Prawns (Penaeus monodon) and its Control Measures Using Plant Extracts

Aims: The study aims to isolate, molecularly identify, and estimate histamine-producing bacteria from Penaeus monodon (tiger prawns) and evaluate their antibiotic resistance and histamine degradation potential using plant extracts.

Study Design: Experimental study involving microbiological, molecular, and chromatographic techniques to analyze bacterial presence and histamine production.

Methodology: Samples were processed using specific agar media (Cetrimide, TCBS, MacConkey, etc.) followed by streaking, broth culturing, and antibiotic susceptibility testing through the disc diffusion method. Bacterial DNA was extracted, amplified using PCR, and sequenced for 16S rRNA identification. Gel electrophoresis confirmed DNA presence, and the bacterial strain was identified as E. coli (NCBI accession number PV156073). Histamine was extracted and quantified using Thin Layer Chromatography (TLC), UV spectrophotometry, and High-Performance Liquid Chromatography (HPLC).

Results: Bacterial isolates obtained from Penaeus monodon exhibited varying degrees of antibiotic resistance, with inhibition zones ranging from 22-26 mm for levofloxacin, 28-29 mm for ciprofloxacin, and 19-26 mm for amikacin. The presence of histamine-producing bacteria was confirmed through TLC analysis, which showed Rf values of 0.6575 and 0.726. UV spectrophotometric analysis further estimated histamine levels, with optical densities of 0.640 in bacterial cultures and 0.625 in raw fish samples. HPLC and FTIR analyses validated the presence of histamine in bacterial supernatants. Additionally, plant extracts from Annona muricata, Jatropha curcas, and Cestrum nocturnum exhibited notable antimicrobial properties, with flavonoid content analysis indicating a potential role in histamine removal. Histamine contamination leads to the formation of intoxications and causes gastrointestinal diseases. The use of natural plant extracts as preservatives can reduce the histamine-contaminating pathogens.

Conclusion: The study successfully identified histamine-producing E. coli in tiger prawns, highlighting potential health risks. Antibiotic resistance patterns and histamine quantification suggest contamination risks in seafood. Plant-based extracts demonstrated potential in mitigating histamine-related allergic reactions, paving the way for natural therapeutic interventions.