Assessment of the Spoilage Microbiota during Refrigerated (4 °C) Vacuum-Packed Storage of Fresh Greek Anthotyros Whey Cheese without or with a Crude Enterocin A-B-P-Containing Extract

Although fresh whey cheeses are prone to rapid deterioration, mainly by psychrotrophic Gram-negative bacteria and lactic acid bacteria (LAB), data on the specific spoilage species in traditional Greek whey cheeses are scarce. Therefore, this study quantified growth and characterized the primary spoilage bacteria in fresh Anthotyros whey cheeses stored at 4 °C in a vacuum for 40 days, without or with an added 5% (v/w) of an enterocin A-B-P crude extract (CEntE). Psychrotrophic Pseudomonas spp., Aeromonas spp., Hafnia spp. and Serratia spp. grew faster than LAB during early storage. However, LAB outgrew the Gram-negative bacteria and prevailed by mid to late storage in all cheese batches, causing a strong or milder batch-dependent natural acidification. Two major non-slime-producing and two minor biotypes of Leuconostoc-like bacteria, all identified as Leuconostoc mesenteroides by 16S rRNA sequencing, dominated the LAB association (76.7%), which also included four subdominant Carnobacterium maltaromaticum biotypes (10.9%), one Leuconostoc lactis biotype (3.3%) and few Lactococcus (1.6%), mesophilic Lactobacillus (0.8%) and Enterococcus (0.8%). Growth and distribution of LAB and Gram-negative species were strongly batch-dependent and plant-dependent. The CEntE neither retarded growth nor altered the whey cheese spoilage association but enhanced LAB growth and the declines of Gram-negative bacteria by late storage.

Neonatal Leuconostoc lactis meningitis

Leuconostoc lactis has a low potential for human infection, although serious infections have been documented in immunocompromised persons. The source of this organism is a dairy product. A 3-day old neonate was presented with multifocal clonic seizures who were given formula feed from birth. We isolated Leuconostoc lactis in his Cerebrospinal fluid (CSF), which is resistant to vancomycin. L. lactis meningitis was treated successfully with the injection of ampicillin-sulbactam.

A Report of Two Cases of Bacteremia by Leuconostoc lactis in Immunocompromised Patients

Background Leuconostoc lactis (L lactis) are gram positive cocci and generally considered to be environmental organisms. They were widely regarded as non-pathogenic and therefore of limited clinical significance. Molecular identification is one technique to identify bacteria.Case reports We presented two cases of bacteremia caused by L lactis. They were both advanced age, history of various diseases, intravenous catheter implantation, parenteral nutrition, longer hospital stay and using of multiple antibiotics. The 16S rRNA genes of the isolates of these two patients´ blood were sequenced. Conclusions When immunocompromised patients with risk factors develop bacteremia caused by L lactis, adequate attention and effective treatment measures should be given.

Production Optimization, Structural Analysis, and Prebiotic- and Anti-Inflammatory Effects of Gluco-Oligosaccharides Produced by Leuconostoc lactis SBC001

Leuconostoc lactis SBC001, isolated from chive, produces glucansucrase and synthesizes oligosaccharides through its enzymatic activity. This study was conducted to optimize oligosaccharide production using response surface methodology, analyze the structure of purified oligosaccharides, and investigate the prebiotic effect on 24 bacterial and yeast strains and the anti-inflammatory activity using RAW 264.7 macrophage cells. The optimal conditions for oligosaccharide production were a culture temperature of 30 °C and sucrose and maltose concentrations of 9.6% and 7.4%, respectively. Based on 1H-NMR spectroscopic study, the oligosaccharides were identified as gluco-oligosaccharides that consisted of 23.63% α-1,4 glycosidic linkages and 76.37% α-1,6 glycosidic linkages with an average molecular weight of 1137 Da. The oligosaccharides promoted the growth of bacterial and yeast strains, including Lactobacillus plantarum, L. paracasei, L. johnsonii, Leuconostoc mesenteroides, L. rhamnosus, and Saccharomyces cerevisiae. When lipopolysaccharide-stimulated RAW 264.7 cells were treated with the oligosaccharides, the production of nitric oxide was decreased; the expression of inducible nitric oxide synthase, tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-10 was suppressed; and the nuclear factor-kappa B signaling pathway was inhibited. In conclusion, the gluco-oligosaccharides obtained from Leu. lactis SBC001 exhibited a prebiotic effect on six bacterial and yeast strains and anti-inflammatory activity in RAW 264.7 macrophage cells.

A Report of Two Cases of Bacteremia by Leuconostoc lactis in Immunocompromised Patients

Background Leuconostoc lactis (L lactis) are gram positive cocci and generally considered to be environmental organisms. They were widely regarded as non-pathogenic and therefore of limited clinical significance. Molecular identification was an important technique to guide antibiotic treatment.Case reports We presented two cases of bacteremia caused by L lactis. They were both advanced age, history of various diseases, intravenous catheter implantation, parenteral nutrition, longer hospital stay and using of multiple antibiotics. The 16S rRNA genes of the isolates of these two patients´ blood were sequenced. Conclusions When immunocompromised patients with risk factors develop bacteremia caused by L lactis, adequate attention and effective treatment measures should given timely.