Pigment-producing Strains Research Articles

Microvirga sesbaniae sp. nov. and Microvirga yunnanensis sp. nov., Pink-Pigmented Bacteria Isolated from Root Nodules of Sesbania cannabina (Retz.) Poir.

Four pigment-producing rhizobial strains nodulating Sesbania cannabina (Retz.) Poir. formed a unique group in genus Microvirga in the phylogeny of a 16S rRNA gene and five housekeeping genes (gyrB, recA, dnaK, glnA, and atpD) in a genome analysis, phenotypic characteristics analysis, and chemotaxonomic analysis. These four strains shared as high as 99.3% similarity with Microvirga tunisiensis LmiM8T in the 16S rRNA gene sequence and, in an MLSA, were subdivided into two clusters, ANI (genome average nucleotide) and dDDH (digital DNA-DNA hybridization) which shared sequence similarities lower than the species thresholds with each other and with the reference strains for related Microvirga species. The polar lipids elucidated that phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and cardiolipin were the main components for strain SWF67558T and for strain HBU65207T, with the exception of PC. SWF67558T and HBU65207T strains had similar predominant cellular fatty acids, including C16:0, C18:0, summed feature 2, and summed feature8, but with different contents. In addition, all the four novel strains produced pink-pigment, and the main coloring material extract from strain SWF67558T was identified as zeaxanthin, which presented antioxidant ability and reduction power. With all the phylogenetic and phenotypic divergency, we proposed these pink-pigmented symbiotic bacteria as two novel species, named Microvirga sesbaniae sp. nov. and Microvirga yunnanensis sp. nov., with SWF67558T (=KCTC82331T=GDMCC1.2024T) and HBU65207T (=KCTC92125T=GDMCC1.2023T) as the type strains, respectively.

Keratinolytic activity of pigmenting and non-pigmenting soils strains of Trichophyton ajelloi

The aim of the study was to evaluate the keratinolytic activity of 37 Trichophyton ajelloi strains, both pigmenting and non–pigmenting, isolated from loamy soil and chernozem, and to identify strains with the highest efficiency of converting feather waste into easily assimilable forms of nitrogen and sulfur for plants. The study showed that among Trichophyton ajelloi strains isolated from loamy soil, pigmenting strains were more capable of biodegrading native feather keratin, while among the strains isolated from chernozem, non–pigmenting strains showed better abilities. The keratinolytic activity, as measured by feather weight loss after 42 days of culture, was on average higher in Trichophyton ajelloi strains isolated from loamy soil compared to those from chernozem. Extracellular keratinase activity, as well as release of soluble proteins and peptides in cultures of Trichophyton ajelloi strains isolated from loamy soil and chernozem increased throughout the experiment. Protease activity was high during the first 7 days of the experiment and increased again from day 28 of culture. The increase in the pH of the culture fluids was associated with the release of ammonium ions. The maximum release of ammonium and sulfate ions occurred on day 21 of culture. Three pigment–producing strains (No. III, XII, and XIV/XV) were among the most active in releasing large amounts of ammonium and sulfate ions. The biodegradation of feather waste by Trichophyton ajelloi strains can be used for the production of fertilizers suitable for the cultivation of plants, particularly those with high sulfur requirements.

АНТИБАКТЕРИАЛЬНЫЙ ЭФФЕКТ ПИГМЕНТОВ ПРЕДСТАВИТЕЛЕЙ РОДА JANTHINOBACTERIUM

Microbial pigments are known among natural sources, including melanin, pyocyanin, bacteriochlorophyll, violacein, prodigiosin and carotenoids, which exhibit a variety of biological activity as antioxidants and demonstrate anti-inflammatory, anti-cancer, antiparasitic and antimicrobial properties. Isolation, research and identification of pigment-producing strains are of interest for the development of biotechnological processes aimed at industrial biosynthesis of these compounds. The antibacterial properties of blue-violet (VIO) and red (RED) pigments of new strains of bacteria IB-ST-GO and IB-ST-GOR isolated from natural waters of the Shulgan-Tash cave's vaucluse spring (Southern Urals) have been studied. Sequence analysis of the 16S rRNA gene revealed that the producers of IB-ST-GO and IB-ST-GOR pigments belong to representatives of Janthinobacterium lividum with a similarity level of 99.72 and 99.86% respectively. The pigments were extracted with 96% ethanol from biomass obtained by cultivating strains on Wakimoto agar medium. According to the results of spectrophotometric analysis, it was found that the VIO pigment belongs to the violacein family, and the RED pigment belongs to the prodigiosin family. The isolated pigments were tested for antibacterial action against 8 types of gram-positive and gram-negative bacteria, inhibitory concentrations of both crude preparations were determined. VIO and RED pigments exhibit an inhibitory effect in the concentration range of 1.0-5.0 mg/ml for a sample of gram-positive bacteria, whereas for gram-negative bacteria, the level of inhibitory concentrations for RED is 10.0-20.0 mg/ml, and for VIO above 20.0 mg/ml. RED pigment exhibits a more dose-dependent effect and a higher selectivity towards gram-positive bacteria than VIO. Together, both pigments are strong inhibitors of the growth of grampositive bacteria, while the antimicrobial activity of both pigments against gram-negative bacteria is low.

ВЛИЯНИЕ ЛЕТУЧИХ СОЕДИНЕНИЙ БАКТЕРИЙ РОДА JANTHINOBACTERIUM НА РАЗВИТИЕ ФИТОПАТОГЕННЫХ ГРИБОВ

Pigment-producing strains IB-ST-GO, IB-ST-RHF, IB-ST-GOLI isolated from the Shulgan-Tash speleosystem catchment were assigned to the Janthinobacterium lividum clade with a similarity level of 99.7-99.8% using the 16S rRNA gene sequence analysis method. The bacterial influence on the development of phytopathogenic fungi Fusarium oxysporum and Rhizoctonia solani by contact and non-contact methods was evaluated. Among the studied bacteria, the strain IB-ST-GO showed antifungal activity, manifested in inhibition of the development of the aerial mycelium of fungi (by 38% for F. oxysporum, 55% for R. solani) due to the formation of volatile metabolites.

Eco-friendly dyeing of polyamide and polyamide-elastane knits with living bacterial cultures of two Streptomyces sp. strains.

Given the environmental burden of textile industry, especially of dyeing processes and the volume of synthetic dyes and surfactants, the intensive development of the greener approaches is under way. Herein, an environmentaly-friendly dyeing of polyamide (PA) and PA/Elastane (PA/EA) knits using live bacterial approach in water environment, completely eliminating usage of textile auxiliaries is described. A total of 12 pigment-producing Streptomyces strains were isolated and purified from soil and rizoshere or bark of smoke tree Cotinus coggygria samples. The antibacterial, antifungal and cytotoxic effects of crude bacterial extracts were tested. Antimicrobial effect was obtained by the majority of extracts but only two streptomycetes extracts, 11-5 and BPS51, showed moderate cytotoxicity against HaCaT human cell line. This was the reason to select 11-5 and BPS51 strains for the dyeing of the textile materials. Excellent properties of dyeing wool, silk and PA are achieved initially using live cultures, and the bioprocess is optimized on commercial PA and PA/EA knits used for stockings production. Satisfactory coloration of both knits is achieved with dynamic conditions (culture shaking at 180rpm over 5-14 days at 30 ºC) giving the best coloration results, except in the case of the PA sample dyed with a bacterial strain 11-5. The prolongation of dyeing time leads to higher color yields independently of fabric and bacteria strain. Although the color differences between the samples before and after washing are observed, washing fastness after three washing cycles can be considered as satisfactory.

Association of multidrug resistance behavior of clinical Pseudomonas aeruginosa to pigment coloration

Pseudomonas aeruginosa is an adaptable bacterial pathogen that infects a variety of organs, including the respiratory tract, vascular system, urinary tract, and central nervous system, causing significant morbidity and mortality. As the primary goal of this study, we wanted to determine how pigment color production differed between clinical strains of P. aeruginosa, and whether or not that variation was associated with multidrug resistance or the ability to form biofilms. We screened in total 30.1% of yellow, 39.8% green and 30.1% of no pigment-producing P. aeruginosa strains from a total of 143 various clinical isolates. Yellow pigment-producing strains presented significant resistance to antibiotics groups, including β-lactam (91.5%), aminoglycosides (70.5%), and carbapenems (51.9%) compared to green and non-pigmented strains. Notably, 16.3% of yellow pigment-producing strains were resistant to colistin which is used as a last-resort treatment for multidrug-resistant bacteria, whereas only 2.3% of non-pigmented and 1.8% of green pigmented strains were resistant to colistin. Aside from that, yellow pigment-producing strains were frequent producers of enzymes belonging to the lactamase family, including ESBL (55.6%), MBL (55.6%), and AmpC (50%). Compared to the green groups (7.14%) and non-pigmented groups (28.5%), they had a higher frequency of efflux positive groups (64.2%). Notably, when compared to non-pigmented groups, green pigment-producing strains also displayed antibiotic susceptibility behavior similar to yellow pigment-producing strains. The majority of yellow pigment-producing strains outperformed the green and non-pigmented strains in terms of MIC levels when compared to the other two groups of strains. Despite the fact that previous studies have demonstrated a direct correlation between multidrug resistance behaviors and biofilm production, no such statistically significant association between pigment and biofilm formation was found in our investigation. Our research has demonstrated that the correlation of bacterial pigments on their susceptibility to antimicrobial agents. Yellow pigment-producing P. aeruginosa strains posed a significant problem due to the lack of alternative agents against such transformed strains, which may be associated with the development of multidrug resistance.Graphical

Isolation and selection of carotenoid-producing bacteria from marine environment and determination of carotenoid extraction condition

The carotenoid is a natural pigment group, which is gradual of interest because of its essential biological activities and great production potentials such as using low-cost material and easy to apply on a large scale. For further development of natural carotenoid products, in this study, fourteen yellow, red, and orange pigment-producing marine bacterial strains were isolated from 25 seawater samples collected along coasts of Phu Quoc island (Kien Giang province), Vung Tau City (Ba Ria – Vung Tau province), Can Gio district (Ho Chi Minh city), and Thang Binh district (Quang Nam province). These isolates were identified belong to seven genera Micrococcus, Kocuria, Microbacterium, Brevibacterium, Bacillus, Rhodococcus and Exiguobacterium with 96.7% - 100% of 16S rRNA sequences identity. Based on carotenoid producing ability and UV-absorbance profile, three of the isolates including Micrococcus sp. 64A3a (yellow), Exiguobacterium sp. YT09 (orange) and Rhodococcus enclensis strain RSA3 (red) were selected for investigation of carotenoid extraction conditions. Methanol at concentration of 100% with ratio of 1 g bacterial cells/10 mL methanol is suitable conditions for extraction of red, orange and yellow pigments from the isolates.

<p><strong><em>Arcopilus amazonicus</em></strong><strong> (Chaetomiaceae), a new fungal species from the Amazon rainforest native plant <em>Paullinia cupana</em></strong></p>

Arcopilus is a genus recently proposed after the taxonomic restructuring of Chaetomium with only seven described species so far. During the characterization of the microbiome of the Amazonian guarana plant (Paullinia cupana var. sorbilis), nine red pigment-producing strains of fungi were isolated. These strains were identified through morphological characterization and phylogenetic analysis based on the internal transcribed spacer (ITS), 28S large subunit (LSU), partial second largest subunit of RNA polymerase II (RPB2) and β-tubulin (TUB2) regions. Moreover, chemical profiles were obtained via high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS), in which the isolated strains were able to produce significant amounts of the polyketide oosporein. The obtained results indicate the occurrence of a new fungal species, A. amazonicus. Chemical analyses showed that oosporein is overproduced by these strains under laboratory culture conditions.

EXTRACTION AND CHARACTERIZATION OF ANTIBACTERIAL PIGMENT FROM ROSEOMONAS GILARDII YP1 STRAIN IN YERCAUD SOIL

Objective: The current study is focused on antibacterial pigment production from Yercaud hills region soil bacteria.
 Methods: In this present study, a soil sample was collected from a coffee plantation in Yercaud, Salem district. The collected soil sample was used to isolate the pigment-producing bacterial strains. The pigments were extracted by acidified ethanol and there used to screen the antibacterial activity against clinical pathogens. The potential antibacterial pigment producer was identifying and the pigment was characterized by ultraviolet spectroscopy, thin-layer chromatography, and Fourier transform infrared (FT-IR) and also evaluate the minimum inhibitory concentration of pigment against clinical pathogens.
 Results: The pigment-producing bacterial strains were isolated from Yercaud soil, among the isolates, YP1 was maximum activity against test pathogens. The potential pigment producer was identified as Roseomonas gilardii. The extracted pigments showed the maximum absorbance at 450 nm and their functional groups were identified using FT-IR analysis.
 Conclusion: Based on the results, the pigment was extracted from R. gilardii and it may serve as potential antibacterial pigment of interest in the food industries, textile industries in natural colorant, and cosmetic industries.

Comparative Study on A Novel Pathogen of European Seabass. Diversity of Aeromonas veronii in the Aegean Sea.

Aeromonas veronii is an emerging pathogen causing severe pathology and mortalities in European seabass aquaculture in the Aegean Sea, Mediterranean. More than 50 strains of the pathogen were characterized biochemically and genetically in order to study the epidemiology of the disease, as well as the phylogeny and virulence of the bacterium. Based on the phenotypic characteristics, the isolates form three groups consisting of: (a) the West Aegean Sea, non-motile, non-pigment-producing strains, (b) the West Aegean Sea, motile, and pigment-producing strains and (c) the East Aegean Sea motile strains that produce minute amounts of pigment. All strains were highly similar at the genomic level; however, the pattern of West/East geographic origin was reflected in biochemical properties, in general genomic level comparison and in the putative virulent factors studied. Type VI secretion system was not detected in the western strains. The outer membrane protein (OMP) profile which contains proteins that are putative antigenic factors, was very similar between strains from the different areas. Although most of the OMPs were detected in all strains with great sequence similarity, diversification according to geographic origin was evident in known antigenic factors such as the maltoporin LamB. A systematic comparative analysis of the strains is presented and discussed in view of the emergence of A. veronii as a significant pathogen for the Mediterranean aquaculture.

Enrichment and characteristics of mixed methane-oxidizing bacteria from a Chinese coal mine.

In methane-rich environments, methane-oxidizing bacteria usually occur predominantly among consortia including other types of microorganisms. In this study, artificial coal bed gas and methane gas were used to enrich mixed methanotrophic cultures from the soil of a coal mine in China, respectively. The changes in microbial community structure and function during the enrichment were examined. The microbial diversity was reduced as the enrichment proceeded, while the capacity for methane oxidation was significantly enhanced by the increased abundance of methanotrophs. The proportion of type II methanotrophs increased greatly from 7.84% in the sampled soil to about 50% in the enrichment cultures, due to the increase of methane concentration. After the microbial community of the cultures got stable, Methylomonas and Methylocystis became the dominant type I and type II methanotrophs, while Methylophilus was the prevailing methylotroph. The sequences affiliated with pigment-producing strains, Methylomonas rubra, Hydrogenophaga sp. AH-24, and Flavobacterium cucumis, could explain the orange appearance of the cultures. Comparing the two cultures, the multi-carbon sources in the artificial coal bed gas caused more variety of non-methanotrophic bacteria, but did not help to maintain the diversity or to increase the quantity and activity of methanotrophs. The results could help to understand the succession and interaction of microbial community in a methane-driven ecosystem.

Novel spectrophotometric approach for determination of validamycin A in fermentation of Streptomyces hygroscopicus

Validamycin A (Val-A), produced by Streptomyces hygroscopicus 5008 in industrial fermentation, is one of the most widely used anti-fungal agro-antibiotics in Asia and high performance liquid chromatography (HPLC) assay is usually used to determine the production of Val-A. A new approach to determine Val-A by spectrophotometer is developed. During the fermentation of S.hygroscopicus 5008, a pigment secretion was found along with the Val-A biosynthesis. There was a stable relationship between the concentration of Val-A and spectral absorption (SA) value of this pigment at 450nm, even in different fermentation cultures or conditions. Using SA value as interior label, a rapid spectrophotometric method for determining Val-A production was established. In comparing Val-A productivity by HPLC method with that by SA method, the relative standard deviation (R.S.D.) was 0.007 (less than 0.05, no variation) and the conditional probability [Pr(T<t)] was 0.3491 (greater than 0.05, no difference) at the optimal time point of Val-A fermentation, which demonstrated SA method was as stable and accurate as standard HPLC method. It was applied successfully to finding positive strains with high Val-A productivity and short fermentation time. SA assay is an accurate and cost-effective method for measuring Val-A and screening high-producing strains, and this work provides a new insight for rapid quantitative analysis of antibiotics in fermentation of pigment-producing strains.

Characterization and detection of toxoflavin-producingBurkholderiain rice straws andDaqufor Chinese Maotai-flavour liquor brewing

Rice straws are widely used in Daqu (starter) preparation for Maotai-flavour liquor brewing to provide adequate thermal insulation, water retention and aeration. As the straws have direct contact with the Daqu during its preparation, the microorganisms carried by the straws can be transferred to the Daqu. In this study, yellow pigment-producing strains were isolated from the rice straws using a dilution plate method. Most of these strains were characterized as toxoflavin-producing Burkholderia spp. by 16S rRNA sequencing, toxA gene-specific PCR and toxoflavin detection. The PCR assays revealed the existence of Burkholderia in the Daqu samples. The toxoflavin content in a number of Daqu samples was determined using HPLC. The highest observed content of toxoflavin in the Daqu was >8 mg/kg, close to its LD50. Although no toxoflavin was detected in the distilled liquor, the safety problem regarding the use of rice straws in Daqu preparation is still noteworthy, since Burkholderia and toxoflavin can be transferred and can accumulate during the brewing process. The results can contribute to a further assessment of the contamination risk in liquor brewing caused by Burkholderia and to safer production in this traditional process. Copyright © 2015 The Institute of Brewing & Distilling

Attenuated virulence of pigment-producing mutant of Aeromonas veronii bv. sobria in HeLa cells and Nile tilapia (Oreochromis niloticus)

Aeromonas species are potential water/foodborne pathogens, whereas Aeromonas veronii bv. sobria is one of the most virulent species to human and fish. Most current experimental evidence has publicized that suicide plasmid dependent IS1-element untargeted integration into A. veronii bv. sobria ATCC 9071T strain was recently used to generate brown pigment-producing and spontaneous pelleting (BP+SP+) mutant. Current study was conducted to compare virulence of wild-type ATCC 9071T strain and its BP+SP+ mutant with respect to cytotoxicity in HeLa cells and lethality in Nile tilapia. It was found that the cytotoxicity of wild-type ATCC 9071T strain to HeLa cells has reached 75% versus 50% for the cytotoxicity of BP+SP+ mutant. Further, the median lethal dose (LD50) of wild-type ATCC 9071T strain in Nile tilapia was 8.25 Log10 colony-forming units (CFU)/ml, compared to 9.16Log10CFU/ml for the LD50 of BP+SP+ mutant. Thus, current study supports the notion that non pigment-producing Aeromonas strains are more virulent than pigment-producing ones.

Suicide Plasmid-Dependent IS1-Element Untargeted Integration into Aeromonas veronii bv. sobria Generates Brown Pigment-Producing and Spontaneous Pelleting Mutant

Foodborne Gram-negative pathogens belonging to the genus Aeromonas are variable in harboring insertion sequence (IS) elements that play an important role in the generation of dysfunctional relatives of known genes. Using suicide plasmids carrying an IS1-element, untargeted integration is a common problem during experimental trials to generate specific mutations by homologous recombination. In this work, different strains of Aeromonas veronii bv. sobria (AeG1 and ATCC 9071T), A. hydrophila ATCC 19570, and A. sobria ATCC 43979T are examined for acquisition of IS1-element from pYAK1 suicide plasmid. It was found that untargeted integration of IS1-element is encountered only in ATCC 9071T strain. Such untargeted integration generates a novel brown pigment-producing and spontaneous pelleting (BP(+)SP(+)) mutant. Furthermore, BP(+)SP(+) mutant strain secretes significantly higher quantity of PilF homologous protein than the wild-type strain and displays an enhanced protein tyrosine phosphorylation activity. Thus, current work shows that Aeromonas spp. strains are variable in their susceptibility for suicide plasmid-dependent IS1-element untargeted integration as well as the susceptible strain is changed to mimic pigment-producing and spontaneous pelleting strains that are naturally occurring among heterogeneous group of foodborne aeromonads.

Characters of homogentisate oxygenase gene mutation and high clonality of the natural pigment-producing Vibrio choleraestrains

BackgroundSome microorganisms can produce pigments such as melanin, which has been associated with virulence in the host and with a survival advantage in the environment. In Vibrio cholerae, studies have shown that pigment-producing mutants are more virulent than the parental strain in terms of increased UV resistance, production of major virulence factors, and colonization. To date, almost all of the pigmented V. cholerae strains investigated have been induced by chemicals, culture stress, or transposon mutagenesis. However, during our cholera surveillance, some nontoxigenic serogroup O139 strains and one toxigenic O1 strain, which can produce pigment steadily under the commonly used experimental growth conditions, were obtained in different years and from different areas. The genes VC1344 to VC1347, which correspond to the El Tor strain N16961 genome and which comprise an operon in the tyrosine catabolic pathway, have been confirmed to be associated with a pigmented phenotype. In the present study, we investigated the mechanism of pigment production in these strains.ResultsSequencing of the VC1344, VC1345, VC1346, and VC1347 genes in these pigmented strains suggested that a deletion mutation in the homogentisate oxygenase gene (VC1345) may be associated with the pigmented phenotype, and gene complementation confirmed the role of this gene in pigment production. An identical 15-bp deletion was found in the VC1345 gene of all six O139 pigment-producing strains examined, and a 10-bp deletion was found in the VC1345 gene of the O1 strain. Strict sequence conservation in the VC1344 gene but higher variance in the other three genes of this operon were observed, indicating the different stress response functions of these genes in environmental adaption and selection. On the basis of pulsed-field gel electrophoresis typing, the pigment-producing O139 strains showed high clonality, even though they were isolated in different years and from different regions. Additionally all these O139 strains belong to the rb4 ribotype, which contains the O139 strains isolated from diarrheal patients, although these strains are cholera toxin negative.ConclusionDysfunction of homogentisate oxygenase (VC1345) causes homogentisate accumulation and pigment formation in naturally pigmented strains of V. cholerae. The high clonality of these strains may correlate to an environmental survival advantage in the V. cholerae community due to their pigment production, and may imply a potential protective function of melanin in environmental survival of such strains.

Rare carotenoids, (3R)-saproxanthin and (3R,2′S)-myxol, isolated from novel marine bacteria (Flavobacteriaceae) and their antioxidative activities

We isolated three orange or yellow pigment-producing marine bacteria, strains 04OKA-13-27 (MBIC08261), 04OKA-17-12 (MBIC08260), and YM6-073 (MBIC06409), off the coast of Okinawa Prefecture in Japan. These strains were classified as novel species of the family Flavobacteriaceae based on their 16S rRNA gene sequence. They were cultured, and the major carotenoids produced were purified by chromatographic methods. Their structures were determined by spectral data to be (3R)-saproxanthin (strain 04OKA-13-27), (3R,2'S)-myxol (strain YM6-073), and (3R,3'R)-zeaxanthin (strains YM6-073 and 04OKA-17-12). Saproxanthin and myxol, which are monocyclic carotenoids rarely found in nature, demonstrated significant antioxidative activities against lipid peroxidation in the rat brain homogenate model and a neuro-protective effect from L-glutamate toxicity.

Metschnikowia strains isolated from botrytized grapes antagonize fungal and bacterial growth by iron depletion.

Noble-rotted grapes are colonized by complex microbial populations. I isolated pigment-producing Metschnikowia strains from noble-rotted grapes that had antagonistic activity against filamentous fungi, yeasts, and bacteria. A red-maroon pigment was formed from a diffusible colorless precursor released by the cells into the medium. The conversion of the precursor required iron and could occur both in the cells (red colonies) and in the medium (red halos around colonies). The intensity of pigmentation was correlated with the intensity of the antimicrobial activity. Mutants that did not form pigment also lacked antifungal activity. Within the pigmented halos, conidia of the sensitive fungi did not germinate, and their hyphae did not grow and frequently lysed at the tips. Supplementation of the medium with iron reduced the size of the halos and the inhibition zones, while it increased the pigment accumulation by the colonies. The iron-binding agent tropolone had a similar effect, so I hypothesize that pigmented Metschnikowia isolates inhibit the growth of the sensitive microorganisms by pigment formation, which depletes the free iron in the medium. As the pigment is a large nondiffusible complex produced in the presence of both low and high concentrations of ferric ions, the proposed mechanism is different from the mechanisms operating in microbes that release siderophores into the environment for iron acquisition.

Zooshikella ganghwensis gen. nov., sp. nov., isolated from tidal flat sediments.

Two red pigment-producing bacterial strains with a metallic green sheen were isolated from a sediment sample of getbol, the Korean tidal flat. Phylogenetic analysis based on 16S rDNA sequences showed that these isolates represent a phyletic lineage within the gamma-Proteobacteria that is distantly related to the genus Hahella. No bacterial species with validly published names showed > or = 92% 16S rRNA similarity with the getbol isolates. The strains were gram-negative, chemo-organotrophic, aerobic and required NaCl (1-7%) for growth. They produced pigments with maximum absorption at 540 nm, which indicated the presence of prodigiosin, a well-known red pigment previously detected in Serratia marcescens. The major isoprenoid quinone was ubiquinone-9. The predominant cellular fatty acids were saturated and monounsaturated straight-chain fatty acids. The DNA G + C contents ranged from 40 to 42 mol%. The combination of physiological, biochemical and chemotaxonomic data clearly separated the test strains from other phylogenetically related genera in the gamma-Proteobacteria. On the basis of polyphasic evidence from this study, it is proposed that the two getbol isolates should be classified in a novel genus, Zooshikella gen. nov., as Zooshikella ganghwensis sp. nov.

Control measures against Serratia marcescens colonization at the neonatal intensive care unit of UOEH hospital

In September 2001, twelve neonatal intensive care unit (NICU) patients were found to be colonized with pigment-producing strains of Serratia marcescens. The UOEH Infection Control Group (ICG) committee investigated the source of this epidemic and carried out several remedial measures. Immediate investigation of both the environment and the hands of health care workers were enforced. The most likely means of transmission was thought to be from the hands contaminated with S. marcescens that was found on antiseptic cotton, kept in shared stainless steel canisters, used for wiping the patients' buttocks. Therefore, we suggested the following interventions: 1) abolish the stainless steel canisters, and prepare antiseptic cottons for each patient, 2) monitor cultures with some specimens for all patients in the NICU, 3) periodically investigate the environment, 4) enforce workers to wash and disinfect their hands before and after patient care, 5) use new gloves for each treatment, 6) re-examine and modify the caring procedures for inpatients by the nursing staff. In January 2002, this nosocomial colonization came to an end without any serious infection. One of the key points of this success was the quick response by the clinical staff and ICG committee members to the laboratory results of bacteriological examinations. Furthermore, the early investigation of reservoir and good communication between the clinical staff and ICG committee members mostly prevented this nosocomial colonization from becoming worse.