ABSTRACT
Exiguobacterium aurantiacum is isolated from a variety of environmental samples but rarely from patients. The aim of the study was to represent isolation of unusual bacterial strains that could cause infection in patients. Final identification was performed using matrix-assisted description/ionization time-of-flight mass spectrometry (MALDI-TOF). Two isolates strains of E. aurantiacum were isolated, one isolate from distilled water used during surgical treatment and the second one from a patient with bacteremia after radical prostatectomy, both sensitive to all tested antimicrobials. Environmental strains could cause infection, especially in immunocompromised patients; therefore, rare bacteria testing is required, in which identification special assistance is provided by an automated system MALDI-TOF.
Subject(s)
Gram-Positive Bacterial Infections , Postoperative Complications , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Exiguobacterium/drug effects , Exiguobacterium/isolation & purification , Gram-Positive Bacterial Infections/drug therapy , Gram-Positive Bacterial Infections/microbiology , Humans , Male , Postoperative Complications/microbiology , Serbia , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Treatment Outcome , Water MicrobiologyABSTRACT
Lipase is an important commercial enzyme with unique and versatile biotechnological applications. This study was conducted to biosynthesize and characterizes alkaliphilic lipase by Exiguobacterium sp. strain AMBL-20T isolated from the glacial water samples of the northeastern (Gilgit-Baltistan) region of Pakistan. The isolated bacterium was identified as Exiguobaterium sp. strain AMBL-20T on the basis of morphological, biochemical, and phylogenetic analysis of 16S rRNA sequences with GenBank accession number MW229267. The bacterial strain was further screened for its lipolytic activity, biosynthesis, and characterization by different parameters with the aim of maximizing lipase activity. Results showed that 2% Olive oil, 0.2% peptone at 25 °C, pH 8, and 24 h of incubation time found optimal for maximum lipase production. The lipase enzyme was partially purified by ammonium sulphate precipitation and its activity was standardized at pH 8 under 30 °C temperature. The enzyme showed functional stability over a range of temperature and pH. Hence, extracellular alkaliphilic lipase from Exiguobacterium sp. is a potential candidate with extraordinary industrial applications, particularly in bio-detergent formulations.
Subject(s)
Exiguobacterium/enzymology , Ice Cover/microbiology , Lipase/metabolism , Enzyme Stability , Exiguobacterium/classification , Exiguobacterium/genetics , Exiguobacterium/isolation & purification , Hydrogen-Ion Concentration , Lipase/isolation & purification , Lipolysis , Pakistan , Phylogeny , RNA, Ribosomal, 16S/genetics , TemperatureABSTRACT
AIMS: To identify the main spoilage bacterium on fresh-cut leafy vegetables and establish a multiplex PCR assay. METHODS AND RESULTS: Based on physiological-biochemical, molecular identification, and artificial contamination tests, the main bacterium to spoil fresh-cut leafy vegetables was identified as Exiguobacterium spp. and Exiguobacterium acetylicum. Comparative genomics showed that P401_RS0117025 and oxi_50,582,462 genes are specific to Exiguobacterium spp. and E. acetylicum. Based on this, three pairs of primer sets to EaG-291, EaS-2B, and Ea16S-12 genes were designed and used to develop a multiplex PCR assay, which exhibited 100% specificity among 16 Exiguobacterium and 10 non-Exiguobacterium strains. Finally, 84 fresh-cut leafy vegetable samples were analyzed by multiplex PCR assay and standard physiological-biochemical experiments, the results showed multiplex PCR assay reached a detection rate of 96%. CONCLUSIONS: The main spoilage bacterium was identified as Exiguobacterium spp. and E. acetylicum on fresh-cut leafy vegetables based on the novel specific genes explored in this study. SIGNIFICANCE AND IMPACT OF STUDY: A rapid, specific, and sensitive PCR assay was developed for the detection of Exiguobacterium spp. and E. acetylicum.
