Kosakonia Cowanii Research Articles

Colonization of the tsetse fly midgut with commensal Kosakonia cowanii Zambiae inhibits trypanosome infection establishment.

Tsetse flies (Glossina spp.) vector pathogenic trypanosomes (Trypanosoma spp.) in sub-Saharan Africa. These parasites cause human and animal African trypanosomiases, which are debilitating diseases that inflict an enormous socio-economic burden on inhabitants of endemic regions. Current disease control strategies rely primarily on treating infected animals and reducing tsetse population densities. However, relevant programs are costly, labor intensive and difficult to sustain. As such, novel strategies aimed at reducing tsetse vector competence require development. Herein we investigated whether Kosakonia cowanii Zambiae (Kco_Z), which confers Anopheles gambiae with resistance to Plasmodium, is able to colonize tsetse and induce a trypanosome refractory phenotype in the fly. Kco_Z established stable infections in tsetse’s gut and exhibited no adverse effect on the fly’s survival. Flies with established Kco_Z infections in their gut were significantly more refractory to infection with two distinct trypanosome species (T. congolense, 6% infection; T. brucei, 32% infection) than were age-matched flies that did not house the exogenous bacterium (T. congolense, 36% infected; T. brucei, 70% infected). Additionally, 52% of Kco_Z colonized tsetse survived infection with entomopathogenic Serratia marcescens, compared with only 9% of their wild-type counterparts. These parasite and pathogen refractory phenotypes result from the fact that Kco_Z acidifies tsetse’s midgut environment, which inhibits trypanosome and Serratia growth and thus infection establishment. Finally, we determined that Kco_Z infection does not impact the fecundity of male or female tsetse, nor the ability of male flies to compete with their wild-type counterparts for mates. We propose that Kco_Z could be used as one component of an integrated strategy aimed at reducing the ability of tsetse to transmit pathogenic trypanosomes.

Isolation and characterization of chromium(VI)-reducing bacteria from tannery effluents and solid wastes.

In the present investigation, five novel Cr(VI) reducing bacteria were isolated from tannery effluents and solid wastes and identified as Kosakonia cowanii MKPF2, Klebsiella pneumonia MKPF5, Acinetobacter gerneri MKPF7, Klebsiella variicola MKPF8 and Serratia marcescens MKPF12 by 16S rDNA gene sequence analysis. The maximum tolerance concentration of Cr(VI) as K2Cr2O7 of the bacterial isolates was varying up to 2000mg/L. Among the investigated bacterial isolates, A. gerneri MKPF7 was best in terms of reduction rate. The optimum temperatures for growth and Cr(VI) reduction by the bacterial isolates were 35 and 40°C, respectively except A. gerneri MKPF7 which grew and reduced Cr(VI) optimally at 40°C. The optimum pH for growth and Cr(VI) reduction by K. cowanii MKPF2, A. gerneri MKPF7 and S. marcescens MKPF12 was 7.0 whereas the optimum pH for growth and Cr(VI) reduction by K. pneumoniae MKPF5 and K. variicola MKPF8 were 7.0, 8.0 and 6.0, 7.0, respectively. All the bacterial isolates showed maximum tolerance against Ni2+ and Zn2+ whereas minimum tolerance was observed against Hg2+ and Cd2+. The bacteria isolated in the present study thus can be used as eco-friendly biological expedients for the remediation and detoxification of Cr(VI) from the contaminated environments.

Mining alfalfa (Medicago sativa L.) nodules for salinity tolerant non-rhizobial bacteria to improve growth of alfalfa under salinity stress

There are fewer reports on plant growth promoting (PGP) bacteria living in nodules as helper to tolerance to abiotic stress such as salinity and drought. The study was conducted to isolate rhizobial and non-rhizobial drought and salinity tolerant bacteria from the surface sterilized root nodules of alfalfa, grown in saline soils, and evaluate the effects of effective isolates on plant growth under salt stress. Based on drought and salinity tolerance of bacterial isolates and having multiple PGP traits, two non-rhizobial endophytic isolates and one rhizobial endophytic isolate were selected for further identification and characterization. Based on partial sequences of 16 S rRNA genes, non-rhizobial isolates and rhizobial isolate were closely related to Klebsiella sp., Kosakonia cowanii, and Sinorhizobium meliloti, respectively. None of the two non-rhizobial strains were able to form nodules on alfalfa roots under greenhouse and in vitro conditions. Co-inoculation of alfalfa plant with Klebsiella sp. A36, K. cowanii A37, and rhizobial strain S. meliloti ARh29 had a positive effect on plant growth indices under salinity stress. In addition, the single inoculation of non-rhizobial strains without rhizobial strain resulted in an increase in alfalfa growth indices compared to the plants non-inoculated and the ones inoculated with S. meliloti ARh29 alone under salinity stress, indicating that nodule non-rhizobial strains have PGP potentials and may be a promising way for improving effectiveness of Rhizobium bio-fertilizers in salt-affected soils.

Comparative antibacterial effects of cellulose nanofiber, chitosan nanofiber, chitosan/cellulose combination and chitosan alone against bacterial contamination of Iranian banknotes

The aims of the current study were to evaluate the antibacterial effects of cellulose nanofiber (CNF), chitosan nanofiber (ChNF), CNF/ChNF combination and chitosan alone (Ch) against the isolated bacterial contaminations from the surface of Iranian banknotes using biochemical, disc diffusion and molecular analyses. The results unveiled that the CNF did not show the significant antibacterial effect against isolated bacterial strains, whereas the combination of CNF/ChNF (at concentration 100 μg/disc 1:1) exhibited the synergistic effects against Stenotrophomonas maltophilia. Also, ChNF (100 μg/disc) and Ch (100 and 200 μg/disc) displayed dose-dependent antibacterial effects against the sensitive bacteria including Bacillus subtilis, Bacillus pumilus, Micrococcus sp. Kosakonia cowanii, Brevibacterium frigoritolerans, Escherichia coli standard ATCC 25922, Staphylococcus aureus standard ATCC 25923. On the other hand, chitosan displayed the highest inhibitory effects against Gram-positive bacteria. Our results showed that the coating of banknotes with these compounds is a novel strategy to reduce the bacterial contaminations and increase the durability (or quality) of banknotes, without being toxic to the surrounding environment.

The Effects of Pantoea and Kosakonia Isolated from Buckwheat Sprouts on Obese Mice

Objective: This study aims to investigate the effects of surface bacteria of buckwheat sprouts on obesity. We examine whether these bacteria have probiotic properties. Methods: Since P-36 and P-37 strains were present in large amounts on the buckwheat sprouts surface, identification of species was carried out by intestinal bacteria identification kit and 16S rRNA gene analysis. Subsequently, to investigate the biological effects, P-36 and P-37 strains were divided into two groups, heat-treated dead bacteria and untreated viable bacteria, which were then orally administered to obese model mice exhibiting hyperglycemia every other day for a total of 10 times. After administration, BMI and visceral fat mass were measured, and oral glucose tolerance test was conducted to evaluate glucose tolerance; their influence on blood glucose level and insulin resistance (HOMA-IR) was evaluated. Results: The strain P-36 was identified as Pantoea sp., and P-37 as Kosakonia cowanii. In the group of mice administered the living and dead bacteria of P-36 and P-37, the weight gain rate after the administration was low, and the progression of obesity was suppressed. In the oral glucose tolerance test, an improvement of glucose tolerance and a significant suppression of blood glucose level was confirmed at 0 and 15 min in the group treated with viable P-37. In addition, HOMA-IR was improved in mice treated with both viable and dead P-37 bacteria. Conclusion: The mice administered P-36 and P-37 showed a gradual increase in body weight and a decrease in visceral fat percentage. The mechanism leading to improved blood glucose levels observed in mice administered P-37 strain remains unclear at present. The involvement of buckwheat sprouts-derived bacteria in improving hyperglycemia and reducing obesity during a short time will help to discover new probiotics.

Complete genome sequence of human pathogen Kosakonia cowanii type strain 888-76T.

Kosakonia cowanii type strain 888-76T is a human pathogen which was originally isolated from blood as NIH group 42. In this study, we report the complete genome sequence of K. cowanii 888-76T. 888-76T has 1 chromosome and 2 plasmids with a total genome size of 4,857,567 bp and C+G 56.15%. This genome sequence will not only help us to understand the virulence features of K. cowanii 888-76T but also provide us the useful information for the study of evolution of Kosakonia genus.

Taxonomic evaluation of the genus Enterobacter based on multilocus sequence analysis (MLSA): Proposal to reclassify E. nimipressuralis and E. amnigenus into Lelliottia gen. nov. as Lelliottia nimipressuralis comb. nov. and Lelliottia amnigena comb. nov., respectively, E. gergoviae and E. pyrinus into Pluralibacter gen. nov. as Pluralibacter gergoviae comb. nov. and Pluralibacter pyrinus comb. nov., respectively, E. cowanii, E. radicincitans, E.

The taxonomy of Enterobacter has a complicated history, with several species transferred to and from this genus. Classification of strains is difficult owing to its polyphyletic nature, based on 16S rRNA gene sequences. It has been previously acknowledged that Enterobacter contains species which should be transferred to other genera. In an attempt to resolve the taxonomy of Enterobacter, MLSA based on partial sequencing of protein-encoding genes (gyrB, rpoB, infB and atpD) was performed on the type strains and reference strains of Enterobacter, Cronobacter and Serratia species, as well as members of the closely related genera Citrobacter, Klebsiella, Kluyvera, Leclercia, Mangrovibacter, Raoultella and Yokenella. Phylogenetic analyses of the concatenated nucleotide sequences revealed that Enterobacter can be divided into five strongly supported MLSA groups, suggesting that the species should be reclassified into five different genera. Further support for this was provided by a concatenated amino acid tree, phenotypic characteristics and fatty acid profiles, enabling differentiation of the MLSA groups. Three novel genera are proposed: Lelliottia gen. nov., Pluralibacter gen. nov. and Kosakonia gen. nov. and the following new combinations: Lelliottia nimipressuralis comb. nov., Lelliottia amnigena comb. nov., Pluralibacter gergoviae comb. nov., Pluralibacter pyrinus comb. nov., Kosakonia cowanii comb. nov., Kosakonia radicincitans comb. nov., Kosakonia oryzae comb. nov., Kosakonia arachidis comb. nov., Cronobacter helveticus comb. nov. and Cronobacter pulveris comb. nov. Additionally, the novel epithet Cronobacter zurichensis nom. nov. is proposed for the reclassification of Enterobacter turicensis into the genus Cronobacter, as Cronobacter turicensis (Iversen et al., 2008) is already in use.