Marinobacter panjinensis sp. nov., a moderately halophilic bacterium isolated from sea tidal flat environment.

Two moderately halotolerant bacterium strains, designated PJ-16T and PJ-38, were isolated from a tidal flat of the red beach in Panjin City, Liaoning Province, PR China. Cells were found to be Gram-stain-negative, aerobic, motile, rod-shaped with a single polar flagellum. Optimum growth of strain PJ-16T occurred at 30 °C, pH 7.0 and 0.2-8.0  % (w/v) NaCl, and strain PJ-38 at 30 °C, pH 6.0-7.0 and 0.2-8.0  % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain PJ-16T was most closely related to Marinobacter denitrificans KCTC 62941T (99.2 % 16S rRNA gene sequence similarity), Marinobacter algicola DSM 16394T (98.6 %), Marinobacter salarius JCM 19399T (98.4 %) and Marinobacter confluentis KCTC 42705T (98.2 %), and strain PJ-38 was most closely related to M. denitrificans KCTC 62941T (99.1 %), M. algicola DSM 16394T (98.6 %), M. salarius JCM 19399T (98.4 %) and M. confluentis KCTC 42705T (98.1 %). The G+C content of the genomic DNA of strain PJ-16T based on its draft genomic sequence was 57.4 mol%. The major cellular fatty acids of strain PJ-16T were C16 : 0, C16 : 1 ω7c/C16 : 1 ω6c and C18 : 1 ω9c. The major respiratory quinone of PJ-16T was ubiquinone-9 and the major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The results of the phenotypic, phylogenetic and genomic analyses revealed that strains PJ-16T and PJ-38 represent a novel species of the genus Marinobacter, and the name Marinobacter panjinensis sp. nov. is proposed. The type strain is PJ-16T (= CGMCC 1.13694T= KCTC 72023T).

Huge anthropogenic microbial load during southwest monsoon season in coastal waters of Kakinada, Bay of Bengal.

To examine the influence of anthropogenic activities on the marine ecosystem near the coastal waters of the port city, Kakinada, a study was conducted to investigate the abundance of heterotrophic, indicator and pathogenic bacteria during the spring inter monsoon (SIM) and southwest monsoon (SWM) seasons. A drastic change in the marine bacteria due to the input of allochthonous bacteria during SWM was noticed. An order of magnitude higher abundance of indicators (Escherichia coli and Enterococcus faecalis) and bacterial pathogens (Proteus mirabilis and Pseudomonas aeruginosa) was observed during SWM. In contrast, Chlorophyll-a, heterotrophic bacterial abundance, Aeromonas hydrophila and Klebsiella pneumoniae were higher during SIM. A significant increase in some of the indicator and pathogenic bacterial abundance due to moderate rainfall suggests that the improper drainage system in the city could spread these bacteria, posing a considerable threat to both environment and human health.

Vogesella urethralis-induced aspiration pneumonia and bacteremia in an elderly man: a first case report and literature review.

BACKGROUND: Vogesella species are common aquatic Gram-negative rods that were first reported in 1997. Vogesella urethralis bacterium was first isolated from human urine in 2020. Only two cases of disease caused by Vogesella species have been reported with no case of Vogesella urethralis-caused disease being reported as yet. Herein, we report a case of aspiration pneumonia and bacteremia caused by Vogesella urethralis. CASE PRESENTATION: An 82-year-old male patient was admitted with dyspnea, increased sputum production, and hypoxia. Gram-negative rods were isolated from the blood and sputum cultures of the patient. He was diagnosed with aspiration pneumonia and bacteremia. Initially, Vogesella urethralis was wrongly identified as Comamonas testosteroni based on fully automated susceptibility testing; however, additional 16S rRNA gene sequencing identified the causative as Vogesella urethralis. The patient was treated with piperacillin and tazobactam. Unfortunately, he developed aspiration pneumonia again and died during hospitalization. CONCLUSIONS: Since no database exists for rare bacteria in traditional clinical microbiology laboratories, 16S rRNA gene sequence analysis is useful. We report the first case of Vogesella urethralis-induced aspiration pneumonia and bacteremia.

A novel approach for the fractionation of organic components and microbial degraders in ADM1 and model validation based on the methanogenic potential.

The anaerobic digestion model No 1 (ADM1), with fixed fractions of the substrate components, is currently used to simulate methane production during the anaerobic digestion (AD) of waste activated sludge (WAS). However, the goodness-of-fit for the simulation is not ideal due to the different characteristics of WAS from different regions. In this study, a novel methodology based on a modern instrumental analysis and 16S rRNA gene sequence analysis for the fractionation of organic components and microbial degraders in the WAS is investigated to modify the fractions of the components in the ADM1. The combination of Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and nuclear magnetic resonance (NMR) analyses were used to achieve a rapid and accurate fractionation of the primary organic matters in the WAS that was verified using both the sequential extraction method and the excitation-emission matrix (EEM). The protein, carbohydrate, and lipid contents in the four different sludge samples measured using the above combined instrumental analyses were 25.0 - 50.0%, 2.0 - 10.0%, and 0.9 - 2.3%. The microbial diversity based on 16S rRNA gene sequence analysis was utilized to re-set the initial fractions of the microbial degraders in the ADM1. A batch experiment was utilized to further calibrate the kinetic parameters in the ADM1. Based on the above optimization of the stoichiometric and kinetic parameters, the ADM1 with full parameter modification for WAS (ADM1-FPM) simulated the methane production of the WAS very well with a Theil's inequality coefficient (TIC) of 0.049, which was increased by 89.8% than that of the default ADM1 fit. The proposed approach, with its rapid and reliable performance, demonstrated a strong application potential for the fractionation of organic solid waste and the modification of ADM1, which contributed to a better simulation of methane production during the AD of organic solid wastes.

Nitratireductor luteus sp. nov. isolated from saline-alkali land.

The Gram-staining negative, oxidase and catalase negative strain KC-ST17T, isolated from saline-alkali land, was characterized using a polyphasic approach to determine its taxonomic position. Using 16S rRNA gene sequence analysis, the highest similarity of strain KC-ST17T was found with Nitratireductor pacificus CCTCC AB 209302T (97.2%). Cells are aerobic, non-motile, and rod-shaped. The isolate was found to be able to grow in NaCl concentrations of 0-4.0%. The assembled genome of strain KC-ST17T had a total length of 4.9 Mb with a G + C content of 62.7%. According to genome analysis, strain KC-ST17T encodes genes involved in the reduction of nitrate to nitrite, which may play a role in the utilization of nitrogenous compounds from the soil as an immediate source of energy. Based on the phenotypic characteristics and phylogenetic analysis, strain KC-ST17T was confirmed to represent a novel species in the Nitratireductor genus; thus, the name Nitratireductor luteus sp. nov. was proposed. The type strain of this species was KC-ST17T (= KCTC 92119T = MCCC 1K07309T).

Sphingobacterium rhinopitheci sp. Nov., isolated from the faeces of Rhinopithecus bieti in China.

A novel bacterium, WQ 047T, was isolated from the faeces of Rhinopithecus bieti, a highly endangered primate endemic to China. The cells were aerobic, oval/rod-shaped, Gram-stain-negative, non-motile, catalase positive, and produced yellow pigmented colonies on Columbia Agar. The taxonomic position of WQ 047T was clarified by applying a polyphasic study based on 16S rRNA gene sequence phylogenetic analysis, extensive biological typing, and whole genome sequencing. Phylogenetic analysis indicated that stain WQ 047T belonged to the genus Sphingobacterium and its 16S rRNA gene sequence exhibited 96.47% pairwise similarity with that of the closest relatives Sphingobacterium nematocida M-SX103T. The calculated whole genome average nucleotide identity (ANI) value between strain WQ 047T and strain M-SX103 was 72.3%. The digital DNA-DNA hybridization value of strain WQ 047T and M-SX103T was 15.73%, which was obtained by calculating the genome-to-genome distance. The major fatty acids were C15:0 iso, C17:0 iso 3-OH, Summed Feature 3 (C16:1 ω7c/C16:1 ω6c) and Summed feature 9 (iso-C17:1ω9c and/or 10-methyl C16:0). The predominant polar lipids were PE, PL and APL. MK-7 was the predominant menaquinone. The G + C content of WQ 047T was 34.89 mol% according to genome analysis. All these characteristics were consistent with those of the genus of Sphingobacterium. Therefore, based on these results, we propose a novel species for which the name Sphingobacterium rhinopitheci sp. Nov. is proposed, with the type strain WQ 047T (= CCTCC AA 2020026T = KCTC82393T).

Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) for Identification of Bacterial Isolates From Horses.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is used for bacterial identification by analyzing the spectra of isolates and comparing them against a database of reference spectra; it is known for its rapidity and accuracy. Although MALDI-TOF MS is used for identification of bacterial isolates from animals, not all animal pathogens are identified correctly. In this study, we used a commercial MALDI-TOF MS identification system to examine 3724 bacterial isolates from horses and their environments. Isolates that could not be identified with MALDI-TOF MS were identified by 16S rRNA gene sequence taxonomic analysis. MALDI-TOF MS could identify 86.2% of the isolates from horses to the species level, showing that this method could be successfully applied for bacterial identification in horses. However, some species known to be equine pathogenic agents including Taylorella equigenitalis and Rhodococcus equi were difficult to identify with MALDI-TOF MS, which might be the result of an inadequate reference database. Some Prevotella, Staphylococcus, and Streptococcus isolates, which could not be identified with either MALDI-TOF MS or 16S rRNA gene sequencing analysis, formed clusters in the 16S rRNA phylogenic tree, and might be unknown species isolated from horses. Adding the spectra of isolates identified in this study to an in-house database might make MALDI-TOF MS a more useful tool for identifying equine isolates.

Vogesella perlucida-induced bacteremia in an advanced-age patient: first case report.

BACKGROUND: Vogesella species are common aquatic, Gram-negative rod-shaped bacteria, originally described in 1997. Vogesella perlucida was first isolated from spring water in 2008. Furthermore, bacterial pathogenicity of Vogesella perlucida has never been reported. Here, we report the first case of rare Vogesella perlucida-induced bacteremia in an advanced-age patient with many basic diseases and history of dexamethasone abuse. CASE PRESENTATION: A 71-year-old female was admitted with inflamed upper and lower limbs, rubefaction, pain and fever (about 40 °C). She had been injured in a fall at a vegetable market and then touched river snails with her injury hands. A few days later, soft tissue infection of the patient developed and worsened. Non-pigmented colonies were isolated from blood cultures of the patient. Initially, Vogesella perlucida was wrongly identified as Sphingomonas paucimobilis by Vitek-2 system with GN card. Besides, we failed to obtain an acceptable identification by the MALDI-TOF analysis. Finally, the isolated strain was identified as Vogesella perlucida by 16S rRNA gene sequences. In addition, the patient recovered well after a continuous treatment of levofloxacin for 12 days. CONCLUSION: Traditional microbiological testing system may be inadequate in the diagnosis of rare pathogenic bacteria. Applications of molecular diagnostics techniques have great advantages in clinical microbiology laboratory. By using 16S rRNA gene sequence analysis, we report the the first case of rare Vogesella perlucida-induced bacteremia.

Diversity and phylogenetic composition of bacterial communities and their association with anthropogenic pollutants in sewage sludge.

Despite wastewater treatment, sewage sludge is often contaminated with multiple pollutants. Their impact on the phylogenetic composition and diversity of prokaryotic communities in sludge samples remains largely unknown. In this study, we analyzed the phylogenetic structure of bacterial communities and diversity in sludge from six waste water treatment plants (WWTPs) and linked this information with the pollutants identified in these samples: eight potentially toxic metals (PTMs) and four groups of organic pollutants [polychlorinated biphenyls (PCBs), polyromantic hydrocarbons (PAHs), brominated flame retardants (BFRs) and organochlorine pesticides (OCPs)]. Alpha diversity measures and the distribution of dominant phyla varied among the samples, with the community from the thermophilic anaerobic digestion (TAD)-stabilized sample from Prague being the least rich and the least diverse and containing on average 36% of 16S rRNA gene sequence reads of the thermotolerant genus Coprothermobacter of the class Clostridia (phylum Firmicutes). Using weighted UniFrac distance-based redundancy analysis (dbRDA), we found that a collection of 5 PTMs: Cr, Cu, Ni, Pb, Zn, and a pair of BFRs: hexabromocyclododecane (HBCD) and tribromodiphenyl ethers (triBDEs) were significantly associated with the bacterial community structure in mesophilic anaerobic digestion (MAD)-stabilized samples, whereas PCBs were observed to be marginally significant. Altogether, 85% of the variance in bacterial community structure could be ascribed to these pollutants. The data presented here contribute to a greater understanding of the ecological effects of combined pollution on the composition and diversity of bacterial communities, hence have the potential to aid in predicting ecosystem functions and/or disruptions associated with pollution.

Half of 'Micrococcus spp.' cases identified by conventional methods are revealed as other life-threatening bacteria with different drug susceptibility patterns by 16S ribosomal RNA gene sequencing.

Bacterial infection during chemotherapy is a fatal complication, therefore precise identification of the pathogenic microorganism is required for treatment. We report that 2 of 4 pediatric patients with malignancy who were diagnosed with Micrococcus spp. infection by conventional methods were finally revealed to have Kytococcus schroeteri and Kocuria marina infection by 16S ribosomal RNA gene sequence analysis (16S rRNA analysis). Although K. schroeteri is morphologically similar to Micrococcus spp., its drug susceptibility profile is quite different from that of Micrococcus spp. K. schroeteri is resistant to penicillin and cephalosporin, which are effective for Micrococcus spp. In fact, penicillin-resistant lethal pneumonia caused by K. schroeteri has been reported in compromised hosts. Based on our results, Micrococcus spp. determined by conventional methods could contain other life-threatening bacteria with different drug susceptibility patterns from Micrococcus spp. To develop an effective empirical treatment for immunocompromised hosts, accumulation of pathogen data by 16S rRNA analysis is required.

Galaxy mothur Toolset (GmT): a user-friendly application for 16S rRNA gene sequencing analysis using mothur.

BACKGROUND: The determination of microbial communities using the mothur tool suite (https://www.mothur.org) is well established. However, mothur requires bioinformatics-based proficiency in order to perform calculations via the command-line. Galaxy is a project dedicated to providing a user-friendly web interface for such command-line tools (https://galaxyproject.org/). RESULTS: We have integrated the full set of 125+ mothur tools into Galaxy as the Galaxy mothur Toolset (GmT) and provided a set of workflows to perform end-to-end 16S rRNA gene analyses and integrate with third-party visualization and reporting tools. We demonstrate the utility of GmT by analyzing the mothur MiSeq standard operating procedure (SOP) dataset (https://www.mothur.org/wiki/MiSeq_SOP). CONCLUSIONS: GmT is available from the Galaxy Tool Shed, and a workflow definition file and full Galaxy training manual for the mothur SOP have been created. A Docker image with a fully configured GmT Galaxy is also available.

Long-term dynamics of the bacterial community in a Swedish full-scale wastewater treatment plant.

The operational efficiency of activated sludge wastewater treatment plants depends to a large extent on the microbial community structure of the activated sludge. The aims of this paper are to describe the composition of the bacterial community in a Swedish full-scale activated sludge wastewater treatment plant, to describe the dynamics of the community and to elucidate possible causes for bacterial community composition changes. The bacterial community composition in the activated sludge was described using 16S rRNA gene libraries and monitored for 15 months by a terminal restriction fragment (T-RF) length polymorphism (T-RFLP) analysis of the 16S rRNA gene. Despite variable environmental conditions, a large fraction of the observed T-RFs were present at all times, making up at least 50% in all samples, possibly representing a relatively stable core fraction of the bacterial community. However, the proportions of the different T-RFs in this fraction as well as the T-RFs in the more variable fraction showed a significant variation over time and temperature. The difference in community composition between summer and winter coincided with observed differences in floc structure. These observations suggest a relationship between floc properties and bacterial community composition, although additional experiments are required to determine causality.

Fast discrimination of bacteria using a filter paper-based SERS platform and PLS-DA with uncertainty estimation.

Rapid and reliable identification of bacteria is an important issue in food, medical, forensic, and environmental sciences; however, conventional procedures are time-consuming and often require extensive financial and human resources. Herein, we present a label-free method for bacterial discrimination using surface-enhanced Raman spectroscopy (SERS) and partial least squares discriminant analysis (PLS-DA). Filter paper decorated with gold nanoparticles was fabricated by the dip-coating method and it was utilized as a flexible and highly efficient SERS substrate. Suspensions of bacterial samples from three genera and six species were directly deposited on the filter paper-based SERS substrates before measurements. PLS-DA was successfully employed as a multivariate supervised model to classify and identify bacteria with efficiency, sensitivity, and specificity rates of 100% for all test samples. Variable importance in projection was associated with the presence/absence of some purine metabolites, whereas confidence intervals for each sample in the PLS-DA model were calculated using a resampling bootstrap procedure. Additionally, a potential new species of bacteria was analyzed by the proposed method and the result was in agreement with that obtained via 16S rRNA gene sequence analysis, thereby indicating that the SERS/PLS-DA approach has the potential to be a valuable tool for the discovery of novel bacteria. Graphical abstract This paper describes the discrimination of bacteria at the genus and species levels, after minimal sample preparation, using paper-based SERS substrates and PLS-DA with uncertainty estimation.

Species identification on 43 clinical non-tuberculosis Mycobacteria isolates from Gansu Province, China / 中国人兽共患病学报

To understand pathogen spectrum of nontuberculosis Mycobacteria (NTM) and the dominant NTM in Gansu Province and provide the scientific basis for the effective prevention and treatment of NTM diseases,875 Mycobacteria isolates were collected from 2012 to 2014 in Lanzhou Pulmonary Hospital,NTM species were identified by means of PNB/TCH differentiate medium and 16S rRNA gene sequence analysis respectively.Forty-six isolats of NTM were identied from 875 PNB/TCH.Then with 16S rRNA gene sequence analysis,the NTM strains were identified to 3 strains of Nocadia and 43 strains of NTM,including M.intracellulare,M.kansasii,M.avium,M.senegalense,M.gordonae,M.szulgai,M.peregrinumand M.fortuitum.Among them,there were 31 strains of M.intracellulare,which accounted for 72.09％ of the total number of NTM strains.The dominant nontuberculosis Mycobacteria in Gansu Province were mainly M.intracellulare.The application of molecular biology can rapidly and accurately identify the species of nontuberculosis Mycobacteria,and can provide relevant evidence for clinical diagnosis and therapy.

16S rRNA gene-based comprehensive analysis of microbial community compositions in a full-scale leachate treatment system.

In this study, we performed a comprehensive analysis of microbial community compositions in leachate and leachate treatment system (14 processes) during dry and rainy seasons (from February to September and from October to January, respectively), at Khanh Son landfill site, Danang City, Vietnam. In this study, raw leachate in dry and rainy seasons was predominated by Arcobacter, Clostridia, Thermotogales, Methanobacteriaceae, and Methanosaeta. During the two seasons, the system had different microbial community compositions. Orders Methanobacteriales, Clostridiales, MBA08 (order-level clone cluster), and Thermotogales predominated the influent, anaerobic pond, and anoxic pond during the dry season, while Campylobacterales and Pseudomonadales orders were predominant in the anaerobic/anoxic systems during the rainy season. In the facultative pond, aerated ponds, sediment tanks, and polishing ponds, predominant orders during the dry season included Actinomycetales, "Saprospirales", Flavobacteriales, Rhizobiales, Rhodospirillales, Burkholderiales, and Alteromonadales; during the rainy season: Sphingobacteriales, Rickettsiales, Sphingomonadales, and Pseudomonadales. In the final post treatment (polishing ponds with vegetation), significant removal of organic matter, total nitrogen, and colour occurred, while nitrogen-fixing and root-associated or related organisms predominated. This suggested that the vegetation in the ponds was essential to achieve the sufficient leachate treatment.

Effect of different heterotrophic plate count methods on the estimation of the composition of the culturable microbial community.

Heterotrophic plate counts (HPC) are routinely determined within the scope of water quality assessment. However, variable HPC methods with different cultivation parameters (i.e., temperature and media type) are applied, which could lead to significant effects in the outcome of the analysis. Therefore the effect of different HPC methods, according to DIN EN ISO 6222 and EPA, on the culturable microbial community composition was investigated by 16S rRNA gene sequence analysis and statistical evaluation was performed. The culturable community composition revealed significant effects assigned to temperature (p < 0.01), while for media type no statistical significance was observed. However, the abundance of certain detected bacteria was affected. Lower temperature (22 °C) showed the abundance of naturally occurring Pseudomonadaceae and Aeromonadaceae, whereas at high temperature (37 °C) numerous Enterobacteriaceae, Citrobacter spp. and Bacilli were identified. The highest biodiversity was detected at lower temperature, especially on R2A medium. These results indicate that different temperatures (low and high) should be included into HPC measurement and selection of media should, ideally, be adjusted to the monitored water source. Accordingly, it can be inferred that the HPC method is more suitable for continuous monitoring of the same water source than for single assessments of a water sample.

Infective Endocarditis: Identification of Catalase-Negative, Gram-Positive Cocci from Blood Cultures by Partial 16S rRNA Gene Analysis and by Vitek 2 Examination.

Streptococci, enterococci and Streptococcus-like bacteria are frequent etiologic agents of infective endocarditis and correct species identification can be a laboratory challenge. Viridans streptococci (VS) not seldomly cause contamination of blood cultures. Vitek 2 and partial sequencing of the 16S rRNA gene were applied in order to compare the results of both methods. STRAINS ORIGINATED FROM TWO GROUPS OF PATIENTS: 149 strains from patients with infective endocarditis and 181 strains assessed as blood culture contaminants. Of the 330 strains, based on partial 16S rRNA gene sequencing results, 251 (76%) were VS strains, 10 (3%) were pyogenic streptococcal strains, 54 (16%) were E. faecalis strains and 15 (5%) strains belonged to a group of miscellaneous catalase-negative, Gram-positive cocci. Among VS strains, respectively, 220 (87,6%) and 31 (12,3%) obtained agreeing and non-agreeing identifications with the two methods with respect to allocation to the same VS group. Non-agreeing species identification mostly occurred among strains in the contaminant group, while for endocarditis strains notably fewer disagreeing results were observed.Only 67 of 150 strains in the mitis group strains obtained identical species identifications by the two methods. Most VS strains belonging to the groups of salivarius, anginosus, and mutans obtained agreeing species identifications with the two methods, while this only was the case for 13 of the 21 bovis strains. Pyogenic strains (n=10), Enterococcus faecalis strains (n=54) and a miscellaneous group of catalase-negative, Gram-positive cocci (n=15) seemed well identified by both methods, except that disagreements in identifications in the miscellaneous group of strains occurred for 6 of 15 strains.

Pseudooutbreak of Acinetobacter spp. Bacteriuria Confirmed by 16S rRNA Gene Sequence Analysis / 감염과화학요법

BACKGROUND: Acinetobacter spp. is increasingly implicated in hospital-acquired infections. We experienced a pseudooutbreak of Bordetella bronchiseptica bacteriuria identified with biochemical tests, that was later identified as Acinetobacter spp. by using 16S rRNA gene sequence analysis. MATERIALS AND METHODS: Five in-ward patients were found to have B. bronchiseptica bacteriuria without symptoms of urinary tract infection between September 23 and 26 of 2005. We conducted pulsed field gel electrophoresis (PFGE) of the bacteria and epidemiological investigation of this pseudooutbreak. In addition, 16S rRNA gene sequence analysis was performed for the verification of the strains. RESULTS: All 5 isolates were identified as B. bronchiseptica with similar antibiogram by VITEK system. There was no evidence of any symptom or sign of urinary tract infection. The source of this pseudooutbreak was not detected even after performing environmental culture and interviews with healthcare workers. We could not get the appropriate results from the first PFGE with XbaI restriction enzyme. B. bronchiseptica is an unusual organism in human so we conducted 16S rRNA gene sequence analysis for verification. The analysis of 16S rRNA gene sequence with 5 isolates demonstrated 99-100% similarity to a sequence of Acinetobacter spp. (AU1523). According to the results of 16S rRNA gene sequence analysis, we performed the second PFGE with SmaI restriction enzyme, which showed indistinguishable pattern among the all 5 isolates. CONCLUSION: This investigation suggests that the combined method of 16s rRNA gene sequence analysis and PFGE would be helpful for investigation of outbreak caused by unusual organisms

Pseudooutbreak of Acinetobacter spp. Bacteriuria Confirmed by 16S rRNA Gene Sequence Analysis / 감염과화학요법

BACKGROUND: Acinetobacter spp. is increasingly implicated in hospital-acquired infections. We experienced a pseudooutbreak of Bordetella bronchiseptica bacteriuria identified with biochemical tests, that was later identified as Acinetobacter spp. by using 16S rRNA gene sequence analysis. MATERIALS AND METHODS: Five in-ward patients were found to have B. bronchiseptica bacteriuria without symptoms of urinary tract infection between September 23 and 26 of 2005. We conducted pulsed field gel electrophoresis (PFGE) of the bacteria and epidemiological investigation of this pseudooutbreak. In addition, 16S rRNA gene sequence analysis was performed for the verification of the strains. RESULTS: All 5 isolates were identified as B. bronchiseptica with similar antibiogram by VITEK system. There was no evidence of any symptom or sign of urinary tract infection. The source of this pseudooutbreak was not detected even after performing environmental culture and interviews with healthcare workers. We could not get the appropriate results from the first PFGE with XbaI restriction enzyme. B. bronchiseptica is an unusual organism in human so we conducted 16S rRNA gene sequence analysis for verification. The analysis of 16S rRNA gene sequence with 5 isolates demonstrated 99-100% similarity to a sequence of Acinetobacter spp. (AU1523). According to the results of 16S rRNA gene sequence analysis, we performed the second PFGE with SmaI restriction enzyme, which showed indistinguishable pattern among the all 5 isolates. CONCLUSION: This investigation suggests that the combined method of 16s rRNA gene sequence analysis and PFGE would be helpful for investigation of outbreak caused by unusual organisms