Antibiotic Combination to Effectively Postpone or Inhibit the In Vitro Induction and Selection of Levofloxacin-Resistant Mutants in Elizabethkingia anophelis.

Fluoroquinolones are potentially active against Elizabethkingia anophelis. Rapidly increased minimum inhibitory concentrations (MICs) and emerging point mutations in the quinolone resistance-determining regions (QRDRs) following exposure to fluoroquinolones have been reported in E. anophelis. We aimed to investigate point mutations in QRDRs through exposure to levofloxacin (1 × MIC) combinations with different concentrations (0.5× and 1 × MIC) of minocycline, rifampin, cefoperazone/sulbactam, or sulfamethoxazole/trimethoprim in comparison with exposure to levofloxacin alone. Of the four E. anophelis isolates that were clinically collected, lower MICs of levofloxacin were disclosed in cycle 2 and 3 of induction and selection in all levofloxacin combination groups other than levofloxacin alone (all p = 0.04). Overall, no mutations were discovered in parC and parE throughout the multicycles inducted by levofloxacin and all its combinations. Regarding the vastly increased MICs, the second point mutations in gyrA and/or gyrB in one isolate (strain no. 1) occurred in cycle 2 following exposure to levofloxacin plus 0.5 × MIC minocycline, but they were delayed appearing in cycle 5 following exposure to levofloxacin plus 1 × MIC minocycline. Similarly, the second point mutation in gyrA and/or gyrB occurred in another isolate (strain no. 3) in cycle 4 following exposure to levofloxacin plus 0.5 × MIC sulfamethoxazole/trimethoprim, but no mutation following exposure to levofloxacin plus 1 × MIC sulfamethoxazole/trimethoprim was disclosed. In conclusion, the rapid selection of E. anophelis mutants with high MICs after levofloxacin exposure could be effectively delayed or postponed by antimicrobial combination with other in vitro active antibiotics.

In Vitro and In Vivo Antimicrobial Activities of Vancomycin and Rifampin against Elizabethkingia anophelis.

Elizabethkingia anophelis has emerged as a critical human pathogen, and a number of isolated reports have described the successful treatment of Elizabethkingia infections with vancomycin, a drug that is typically used to target Gram-positive bacteria. This study employed in vitro broth microdilution checkerboard and time-kill assays, as well as in vivo zebrafish animal models to evaluate the individual and combination antimicrobial effects of vancomycin and rifampin against E. anophelis. The minimum inhibitory concentration ranges of vancomycin and rifampin against 167 isolates of E. anophelis were 16-256 mg/L and 0.06-128 mg/L, respectively. The checkerboard assay results revealed a synergistic effect between vancomycin and rifampin in 16.8% (28/167) of the isolates. Time-kill assays were implemented for 66 isolates, and the two-drug combination had a synergistic interaction in 57 (86.4%) isolates. In vivo zebrafish studies revealed that treatment with vancomycin monotherapy, rifampin monotherapy, or vancomycin-rifampin combination therapy yielded a higher survival rate than the control group treatment with 0.9% saline. The results of this study support the use of vancomycin to treat E. anophelis infections.

Validation of 16S rRNA and Complete rpoB Gene Sequence Analysis for the Identification of Elizabethkingia Species.

Bacteria in the genus Elizabethkingia have emerged as a cause of life-threatening infections in humans. However, accurate species identification of these pathogens relies on molecular techniques. We aimed to evaluate the accuracy of 16S rRNA and complete RNA polymerase ß-subunit (rpoB) gene sequences in identifying Elizabethkingia species. A total of 173 Elizabethkingia strains with whole-genome sequences in GenBank were included. The 16S rRNA gene and rpoB gene sequences from the same Elizabethkingia strains were examined. Of the 41 E. meningoseptica strains, all exhibited >99.5% 16S rRNA similarity to its type strain. Only 83% of the 99 E. anophelis strains shared >99.5% 16S rRNA gene similarity with its type strain. All strains of E. meningoseptica and E. anophelis formed a cluster distinct from the other Elizabethkingia species in the 16S rRNA and rpoB gene phylogenetic trees. The polymorphisms of 16S rRNA gene sequences are not sufficient for constructing a phylogenetic tree to discriminate species in the E. miricola cluster (E. miricola, E. bruuniana, E. occulta, and E. ursingii). The complete rpoB gene phylogenetic tree clearly delineates all strains of Elizabethkingia species. The complete rpoB gene sequencing could be a useful complementary phylogenetic marker for the accurate identification of Elizabethkingia species.

Effect of Intragenomic Sequence Heterogeneity among Multiple 16S rRNA Genes on Species Identification of Elizabethkingia.

Accurate identification of Elizabethkingia species mostly requires the use of molecular techniques, and 16S rRNA gene sequencing is generally considered the method of choice. In this study, we evaluated the effect of intraspecific diversity among the multiple copies of the 16S rRNA gene on the accuracy of species identification in the genus Elizabethkingia. Sequences of 16S rRNA genes obtained from the 32 complete whole-genome sequences of Elizabethkingia deposited in GenBank and from 218 clinical isolates collected from 5 hospitals in Taiwan were analyzed. Four or five copies of 16S rRNA were identified in the Elizabethkingia species with complete genome sequences. The dissimilarity among the copies of the16S rRNA gene was <1% in all Elizabethkingia strains. E. meningoseptica demonstrated a significantly higher rate of nucleotide variations in the 16S rRNA than did E. anophelis (P = 0.011). Nucleotide alterations occurred more frequently in regions V2 and V6 than in other hypervariable regions (P < 0.001). E. meningoseptica, E. anophelis, and E. argenteiflava strains were clustered distinctly in the phylogenetic tree inferred from 16S rRNA genes, and the intragenomic variation of gene sequences had no profound effect on the classification of taxa. However, E. miricola, E. bruuniana, E. ursingii, and E. occulta were grouped closely in the phylogenetic analysis, and the variation among the multiple copies of the 16S rRNA in one E. ursingii strain affected species classification. Other marker genes may be required to supplement the species classification of closely related taxa in the genus Elizabethkingia. IMPORTANCE Incorrect identification of bacterial species would influence the epidemiology and clinical analysis of patients infected with Elizabethkingia. The results of the present study suggest that 16S rRNA gene sequencing should not be considered the gold standard for the accurate identification of Elizabethkingia species.

Mutant Prevention Concentrations of Ciprofloxacin and Levofloxacin and Target Gene Mutations of Fluoroquinolones in Elizabethkingia anophelis.

Fluoroquinolones are potentially effective against Elizabethkingia anophelis. We investigated the MIC, mutant prevention concentration (MPC), and target gene mutations of fluoroquinolones in E. anophelis. Eighty-five E. anophelis isolates were collected from five hospitals in Taiwan. The MIC and MPC of ciprofloxacin and levofloxacin were examined for all E. anophelis except 17 isolates, in which ciprofloxacin MPC could not be determined due to drug precipitation caused by overly high drug concentration. Mutations in the quinolone resistance-determining regions of DNA gyrase (GyrA and GyrB) and topoisomerase IV (ParC and ParE) in the clinical isolates and fluoroquinolone-selected mutants were examined. Overall, 23.5% and 71.8% of the isolates tested were susceptible to ciprofloxacin and levofloxacin, respectively. The MPC50 of ciprofloxacin was 128 mg/L, and the MPC50 of levofloxacin was 51.2 mg/L. The MPC50/MIC50 ratio for ciprofloxacin was 64, whereas that for levofloxacin was 25.6. The coefficient of determination between the MPC and MIC for ciprofloxacin and levofloxacin was 0.72 and 0.56, respectively, in the linear regression analysis. Preexisting mutations in GyrA (S83I, S83R, and D87Y) were identified in 18 clinical isolates, all of which were resistant to both ciprofloxacin and levofloxacin. Additional amino acid substitutions in GyrA were identified in all ciprofloxacin- and levofloxacin-selected mutants. Furthermore, GyrB alterations (D431N or D431H) were found in nine levofloxacin-treated isolates. Given that maintaining the serum concentrations of fluoroquinolones above MPCs is impossible under presently recommended doses, the selection of mutant E. anophelis strains seems inevitable.

Epidemiology and risk factors of scrub typhus in Taiwan: A nationwide database study from 1996 to 2014.

BACKGROUND: Scrub typhus (ST) is one of the most underdiagnosed, potentially fatal febrile diseases in the Asia-Pacific region. We conducted a comprehensive review of the risk factors of ST over 19 years using data from a nationwide database. METHODS: We used data on ST from the nationwide database of the Taiwan Centers for Disease Control from 1996 to 2014 to analyse the incidence rates and relative risks of ST according to different regions. The trends of incidence rates over the study period were also evaluated. The distribution of confirmed ST cases was mapped using geographic information system software. The characteristics of confirmed ST cases and non-ST cases (cases with suspected ST but negative test findings) were compared. RESULTS: Among the 38,127 reported cases, there were 6,791 (17.8%) confirmed ST cases. The overall incidence rate of ST in Taiwan was 1.49 per 100,000 residents per year. The trend of incidence rates increased over time. The Island region had the highest incidence rate (56.55 per 100,000 residents per year), followed by the Eastern region (15.13 per 100,000 residents per year). More confirmed ST cases were distributed in mountainous areas of Taiwan Main Island and Island region. Compared to non-ST cases, individuals with confirmed ST were younger (median [interquartile range] age: 44 [26-57] years versus 45 [30-60] years, p < .001) and more likely to engage in at-risk occupations (29.4% versus 13.3%, p < .001), including farming and animal husbandry (16.6% versus 9.0%, p < .001) and the armed forces (12.3% versus 3.5%, p < .001); however, they had a lower rate of animal contact (12.8% versus 20.1%, p < .001). CONCLUSIONS: ST is an endemic disease in Taiwan, particularly in the Island region, Eastern region and mountainous areas. Patients engaged in at-risk occupations and presenting with acute febrile diseases should undergo investigations for ST.

Comparative Analysis of Gradient Diffusion and Disk Diffusion with Agar Dilution for Susceptibility Testing of Elizabethkingia anophelis.

Elizabethkingia anophelis has recently emerged as a cause of life-threatening infections. This study compared the results of antimicrobial susceptibility testing (AST) conducted for E. anophelis through different methods. E. anophelis isolates collected between January 2005 and June 2019 were examined for their susceptibility to 14 antimicrobial agents by using disk diffusion, gradient diffusion (Etest; bioMérieux S.A., Marcy l'Etoile, France), and agar dilution methods. The agar dilution method was the reference assay. According to the agar dilution method, the isolates exhibited the highest susceptibility to minocycline (100%), doxycycline (97.6%), rifampin (95.2%), and levofloxacin (78.6%). A very major error rate of >1.5% was observed for nine antibiotics tested using the disk diffusion method. The overall categorical agreement rate between the disk diffusion and agar dilution methods was 74.8%, and ceftazidime, minocycline, levofloxacin, and rifampin met the minimum requirements for discrepancy and agreement rates. The Etest method tended to produce lower log2 minimum inhibitory concentrations for the antibiotics, except for trimethoprim-sulfamethoxazole and rifampin; the method resulted in very major errors for nine antibiotics. The overall essential and categorical agreement rates between the Etest and agar dilution methods were 67.3% and 76.1%, respectively. The Etest method demonstrated acceptable discrepancy and agreement rates for ceftazidime, minocycline, doxycycline, levofloxacin, and rifampin. AST results obtained through the disk diffusion and Etest methods for multiple antibiotics differed significantly from those obtained using the agar dilution method. These two assays should not be a routine alternative for AST for E. anophelis.

Antimicrobial Effects of Minocycline, Tigecycline, Ciprofloxacin, and Levofloxacin against Elizabethkingia anophelis Using In Vitro Time-Kill Assays and In Vivo Zebrafish Animal Models.

Elizabethkingia anophelis is a multidrug-resistant pathogen. This study evaluated the antimicrobial activity of minocycline, tigecycline, ciprofloxacin, and levofloxacin using in vitro time-kill assays and in vivo zebrafish animal models. The E. anophelis strain ED853-49 was arbitrarily selected from a bacterial collection which was concomitantly susceptible to minocycline, tigecycline, ciprofloxacin, and levofloxacin. The antibacterial activities of single agents at 0.5-4 × minimum inhibitory concentration (MIC) and dual-agent combinations at 2 × MIC using time-kill assays were investigated. The therapeutic effects of antibiotics in E. anophelis-infected zebrafish were examined. Both minocycline and tigecycline demonstrated bacteriostatic effects but no bactericidal effect. Minocycline at concentrations ≥2 × MIC and tigecycline at concentrations ≥3 × MIC exhibited a long-standing inhibitory effect for 48 h. Bactericidal effects were observed at ciprofloxacin and levofloxacin concentrations of ≥3 × MIC within 24 h of initial inoculation. Rapid regrowth of E. anophelis occurred after the initial killing phase when ciprofloxacin was used, regardless of the concentration. Levofloxacin treatment at the concentration of ≥2 × MIC consistently resulted in the long-lasting and sustainable inhibition of bacterial growth for 48 h. The addition of minocycline or tigecycline weakened the killing effect of fluoroquinolones during the first 10 h. The minocycline-ciprofloxacin or minocycline-levofloxacin combinations achieved the lowest colony-forming unit counts at 48 h. Zebrafish treated with minocycline or a combination of minocycline and levofloxacin had the highest survival rate (70%). The results of these in vitro and in vivo studies suggest that the combination of minocycline and levofloxacin is the most effective therapy approach for E. anophelis infection.

Coexistence of disseminated Kaposi sarcoma and multicentric Castleman disease in an HIV-infected patient under viral suppression.

Coexistence of multicentric Castleman disease and Kaposi sarcoma is rare and might be missed without an experienced pathologists' interpretation. A 46-year-old man had been diagnosed with HIV infection and treated with combination antiretroviral therapy of dolutegravir/abacavir/lamivudine (Triumeq) for one year. The latest viral load was 49 copies/mL and CD4 T-cell count was 192 cells/uL. He was admitted due to fever off and on, splenomegaly, general lymphadenopathy, and severe thrombocytopenia for two months. Biopsy of a purplish skin lesion and gastric tissue showed Kaposi sarcoma. The pathology of inguinal lymph nodes revealed coexistence of Kaposi sarcoma and multicentric Castleman disease. The plasma Kaposi sarcoma herpesvirus viral load was 365,000 copies/mL. During hospitalization, progressive pancytopenia and spiking fever persisted, and he died of multi-organ failure before completion of chemotherapeutic treatments with rituximab plus liposomal doxorubicin.

Serum C-reactive protein and procalcitonin values in acute Q fever, scrub typhus, and murine typhus.

BACKGROUND: Although C-reactive protein (CRP) and procalcitonin (PCT) are widely used inflammatory markers for infectious diseases, their role and potential application for rickettsioses were rarely studied. METHODS: A retrospective chart review and serological study were conducted in patients with rickettsioses. The clinical presentations, characteristics, laboratory data, and treatment responses were recorded and their associations with CRP and PCT values were analyzed. RESULTS: A total of 189 cases of rickettsioses, including 115 cases of acute Q fever (60.8%), 55 cases of scrub typhus (29.1%), and 19 cases of murine typhus (10.1%) were investigated. Both CRP and PCT values increased in the acute phase and declined in the convalescent phase. In the acute phase, mean CRP and PCT values were 78.2 ± 63.7 mg/L and 1.05 ± 1.40 ng/mL, respectively. Percentages of patients falling under different cut-off values of CRP and PCT were calculated systematically. Only 10.8% of CRP was > 150 mg/L and 14.2% of PCT was > 2.0 ng/mL. Patients with delayed responses to doxycycline treatment (> 3 days from treatment to defervescence) had significantly higher CRP values (102.7 ± 77.1 vs. 72.2 ± 58.2 mg/L, p = 0.041) and more PCT > 1.0 ng/ml (48.4% vs. 26.0%, p = 0.019) in the acute phase; higher CRP values (19.1 ± 37.4 vs. 3.6 ± 13.1 mg/L, p = 0.049) and more PCT > 0.5 ng/ml (19.2% vs. 1.4%, p = 0.005) in the convalescent phase. Correlation analysis was conducted for patients with acute Q fever. CRP and PCT values were positively correlated to each other, and both markers also had a positive correlation with serum aspartate transaminase values. Both CRP and PCT values and white blood cell counts were positively correlated to the days needed from doxycycline treatment to defervescence. CONCLUSION: CRP and PCT values might be useful in clinical investigations for patients with suspected rickettsioses and in predicting the response to doxycycline treatment for rickettsioses.

The epidemiology, characteristics and outbreaks of human leptospirosis and the association with animals in Taiwan, 2007-2014: A nationwide database study.

BACKGROUND: Leptospirosis (LS) is a neglected tropical zoonosis of global importance. A nationwide investigation of characteristics, epidemiology, risk factors and outbreak is crucial for awareness of this disease. METHODS: A nationwide database of reported LS cases from October 2007 to December 2014 obtained from the Centers for Disease Control, Taiwan, was analysed. Geographic information system software was used to map the distribution of confirmed LS cases and pigs. Cross-matching with the databases of Q fever, scrub typhus and murine typhus was conducted to identify possible coinfections. RESULTS: A total of 10,917 reported cases of LS were recorded in the database, which included 665 (6.1%) confirmed LS and 10,252 (93.9%) non-confirmed LS cases. The major residences of confirmed LS were the Kaohsiung-Pingtung (248, 37.3%) and Taipei (174, 26.2%) regions. The average annual incidence was 0.4/100,000 people. Compared with non-confirmed LS cases, confirmed LS cases had significantly higher percentages of male gender (83.6% vs. 67.9%, p < .001), high-risk occupations (farmer, animal husbandry or veterinarian) (24.8% vs. 13.7%, p < .001), residence in the Kaohsiung-Pingtung region (37.3% vs. 19.6%, p < .001) and exposure to rats (8.6% vs. 4.9%, p = .001) or pigs (9.4% vs. 1.9%, p < .001) but a lower mean age (47.8 ± 15.1 vs. 51.±18.5 years old). Rat and pig exposure trends were found in the northern and southern regions, respectively. Distribution of LS was consistent with pigs, and one outbreak associated with flooding and pigs occurred in the Pingtung region in 2009. Twenty-three and four patients with LS were coinfected with scrub typhus and Q fever, respectively. CONCLUSIONS: LS is an endemic disease in Taiwan, particularly in the Kaohsiung-Pingtung and Taipei regions. High-risk occupations and animal exposure history are important for the clinical presumptive diagnosis of LS, particularly for rats in northern Taiwan and pigs in southern Taiwan. Although uncommon, clinicians should be aware of coinfection of LS with endemic rickettsial diseases.

Comparative Genomics of 86 Whole-Genome Sequences in the Six Species of the Elizabethkingia Genus Reveals Intraspecific and Interspecific Divergence.

Bacteria of the genus Elizabethkingia are emerging infectious agents that can cause infection in humans. The number of published whole-genome sequences of Elizabethkingia is rapidly increasing. In this study, we used comparative genomics to investigate the genomes of the six species in the Elizabethkingia genus, namely E. meningoseptica, E. anophelis, E. miricola, E. bruuniana, E. ursingii, and E. occulta. In silico DNA-DNA hybridization, whole-genome sequence-based phylogeny, pan genome analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed, and clusters of orthologous groups were evaluated. Of the 86 whole-genome sequences available in GenBank, 21 were complete genome sequences and 65 were shotgun sequences. In silico DNA-DNA hybridization clearly delineated the six Elizabethkingia species. Phylogenetic analysis confirmed that E. bruuniana, E. ursingii, and E. occulta were closer to E. miricola than to E. meningoseptica and E. anophelis. A total of 2,609 clusters of orthologous groups were identified among the six type strains of the Elizabethkingia genus. Metabolism-related clusters of orthologous groups accounted for the majority of gene families in KEGG analysis. New genes were identified that substantially increased the total repertoire of the pan genome after the addition of 86 Elizabethkingia genomes, which suggests that Elizabethkingia has shown adaptive evolution to environmental change. This study presents a comparative genomic analysis of Elizabethkingia, and the results of this study provide knowledge that facilitates a better understanding of this microorganism.

Elizabethkingia Infections in Humans: From Genomics to Clinics.

The genus Elizabethkingia has recently emerged as a cause of life-threatening infections in humans, particularly in immunocompromised patients. Several new species in the genus Elizabethkingia have been proposed in the last decade. Numerous studies have indicated that Elizabethkingia anophelis, rather than Elizabethkingia meningoseptica, is the most prevalent pathogen in this genus. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry systems with an extended spectrum database could reliably identify E. anophelis and E. meningoseptica, but they are unable to distinguish the remaining species. Precise species identification relies on molecular techniques, such as housekeeping gene sequencing and whole-genome sequencing. These microorganisms are usually susceptible to minocycline but resistant to most ß-lactams, ß-lactam/ß-lactam inhibitors, carbapenems, and aminoglycosides. They often exhibit variable susceptibility to piperacillin, piperacillin-tazobactam, fluoroquinolones, and trimethoprim-sulfamethoxazole. Accordingly, treatment should be guided by antimicrobial susceptibility testing. Target gene mutations are markedly associated with fluoroquinolone resistance. Knowledge on the genomic characteristics provides valuable insights into in these emerging pathogens.

Elizabethkingia bruuniana Infections in Humans, Taiwan, 2005-2017.

Using 16S rRNA and rpoB gene sequencing, we identified 6 patients infected with Elizabethkingia bruuniana treated at E-Da Hospital (Kaohsiung, Taiwan) during 2005-2017. We describe patient characteristics and the molecular characteristics of the E. bruuniana isolates, including their MICs. Larger-scale studies are needed for more robust characterization of this pathogen.

Clinicoepidemiologic characteristics of scrub typhus and murine typhus: A multi-center study in southern Taiwan.

BACKGROUND: This study aimed to offer key features to differentiate scrub typhus (ST) and murine typhus (MT) at the early stage of the diseases and provide clinicoepidemiologic characteristics of ST and MT in southern Taiwan, a region where both diseases are endemic. Comparison of doxycycline treatment efficacy between the two diseases by matching disease severity and delayed treatment had never been investigated. METHODS: We reviewed the medical records of cases of ST and MT in four hospitals in southern Taiwan. Propensity-score matching was used to analyze the defervescence curves between patients with doxycycline-treated ST and MT by log-rank test. RESULTS: Between 2004 and 2016, 265 ST and 63 MT cases were diagnosed. The number of cases of ST was significantly related to temperature (Rs = 0.77) and rainfall (Rs = 0.63). Island area exposure, arthropod bite, eschar, and lymphadenopathy were only recorded in ST patients. Multivariate analysis revealed that mountainous area exposure (odds ratio [OR], 11.0; 95% confidence interval [CI], 4.4-27.2) was an independent predictor for ST, while contact with rats (OR, 8.4; 95% CI, 3.3-21.3) was that for MT. After propensity-score matching, there was no difference in defervescence curves between these two rickettsioses treated with doxycycline (p = 0.24). CONCLUSION: In the present study, island area exposure, arthropod bite, eschar, and lymphadenopathy were unique manifestations of ST. Mountainous area exposure is a predictive factor for ST, while contact with rats predicted MT. There was no difference in defervescence time between these two rickettsioses after doxycycline treatment.

Correction: Jiun-Nong Lin; Chung-Hsu Lai; Chih-Hui Yang and Yi-Han Huang. Comparison of Clinical Manifestations, Antimicrobial Susceptibility Patterns, and Mutations of Fluoroquinolone Target Genes between Elizabethkingia meningoseptica and Elizabethkingia anophelis Isolated in Taiwan. Journal of Clinical Medicine 2018, 7, 538.

The authors wish to make the following corrections to this paper [...].

Genomic Features, Comparative Genomic Analysis, and Antimicrobial Susceptibility Patterns of Chryseobacterium arthrosphaerae Strain ED882-96 Isolated in Taiwan.

Bacteria belonging to the genus Chryseobacterium are ubiquitously distributed in natural environments, plants, and animals. Except C. indologenes and C. gleum, other Chryseobacterium species rarely cause human diseases. This study reported the whole-genome features, comparative genomic analysis, and antimicrobial susceptibility patterns of C. arthrosphaerae ED882-96 isolated in Taiwan. Strain ED882-96 was collected from the blood of a patient who had alcoholic liver cirrhosis and was an intravenous drug abuser. This isolate was initially identified as C. indologenes by using matrix-assisted laser desorption ionization-time of flight mass spectrometry. The analysis of 16S ribosomal RNA gene sequence revealed that ED882-96 shared 100% sequence identity with C. arthrosphaerae type strain CC-VM-7T. The results of whole-genome sequencing of ED882-96 showed two chromosome contigs and one plasmid. The total lengths of the draft genomes of chromosome and plasmid were 4,249,864 bp and 435,667 bp, respectively. The findings of both in silico DNA-DNA hybridization and average nucleotide identity analyses clearly demonstrated that strain ED882-96 was a species of C. arthrosphaerae. A total of 83 potential virulence factor homologs were predicted in the whole-genome sequencing of strain ED882-96. This isolate was resistant to all tested antibiotics, including ß-lactams, ß-lactam/ß-lactamase inhibitor combinations, aminoglycosides, fluoroquinolones, tetracycline, glycylcycline, and trimethoprim-sulfamethoxazole. Only one antibiotic resistance gene was recognized in the plasmid. By contrast, many antibiotic resistance genes were identified in the chromosome. The findings of this study suggest that strain ED882-96 is a highly virulent and multidrug-resistant pathogen. Knowledge regarding genomic characteristics and antimicrobial susceptibility patterns provides valuable insights into this uncommon species.

Genomic Features, Comparative Genomics, and Antimicrobial Susceptibility Patterns of Elizabethkingia bruuniana.

Elizabethkingia bruuniana is a novel species of the Elizabethkingia genus. There is scant information on this microorganism. Here, we report the whole-genome features and antimicrobial susceptibility patterns of E. bruuniana strain EM798-26. Elizabethkingia strain EM798-26 was initially identified as E. miricola. This isolate contained a circular genome of 4,393,011 bp. The whole-genome sequence-based phylogeny revealed that Elizabethkingia strain EM798-26 was in the same group of the type strain E. bruuniana G0146T. Both in silico DNA-DNA hybridization and average nucleotide identity analysis clearly demonstrated that Elizabethkingia strain EM798-26 was a species of E. bruuniana. The pan-genome analysis identified 2,875 gene families in the core genome and 5,199 gene families in the pan genome of eight publicly available E. bruuniana genome sequences. The unique genes accounted for 0.2-12.1% of the pan genome in each E. bruuniana. A total of 59 potential virulence factor homologs were predicted in the whole-genome of E. bruuniana strain EM798-26. This isolate was nonsusceptible to multiple antibiotics, but susceptible to aminoglycosides, minocycline, and levofloxacin. The whole-genome sequence analysis of E. bruuniana EM798-26 revealed 29 homologs of antibiotic resistance-related genes. This study presents the genomic features of E. bruuniana. Knowledge of the genomic characteristics provides valuable insights into a novel species.

Differences in Clinical Manifestations, Antimicrobial Susceptibility Patterns, and Mutations of Fluoroquinolone Target Genes between Chryseobacterium gleum and Chryseobacterium indologenes.

Chryseobacterium infections are uncommon, and previous studies have revealed that Chryseobacterium gleum is frequently misidentified as Chryseobacterium indologenes We aimed to explore the differences in clinical manifestations and antimicrobial susceptibility patterns between C. gleum and C. indologenes The database of a clinical microbiology laboratory was searched to identify patients with Chryseobacterium infections between 2005 and 2017. Species were reidentified using 16S rRNA gene sequencing, and patients with C. gleum and C. indologenes infections were included in the study. A total of 42 C. gleum and 84 C. indologenes isolates were collected from consecutive patients. A significant increase in C. indologenes incidence was observed. C. gleum was significantly more associated with bacteremia than C. indologenes Patients with C. gleum infections had more comorbidities of malignancy and liver cirrhosis than those with C. indologenes infections. The overall case fatality rate was 19.8%. Independent risk factors for mortality were female sex and C. indologenes infection. These isolates were most susceptible to minocycline (73%), followed by trimethoprim-sulfamethoxazole (47.6%), tigecycline (34.1%), and levofloxacin (32.5%). C. gleum exhibited a significantly higher rate of susceptibility than C. indologenes to piperacillin, piperacillin-tazobactam, ceftazidime, tigecycline, and levofloxacin. Alterations in DNA gyrase subunit A were identified to be associated with fluoroquinolone resistance in C. indologenes No nonsynonymous substitutions were observed in the quinolone resistance-determining regions (QRDRs) of C. gleum Differences in epidemiology, clinical manifestations, and antimicrobial susceptibility patterns exist between C. gleum and C. indologenes Additional investigations are needed to explore the significance of these differences.

Comparison of Clinical Manifestations, Antimicrobial Susceptibility Patterns, and Mutations of Fluoroquinolone Target Genes between Elizabethkingia meningoseptica and Elizabethkingia anophelis Isolated in Taiwan.

Elizabethkingia meningoseptica and Elizabethkingia anophelis are two major pathogens in the genus Elizabethkingia. Studies have revealed that Elizabethkingia anophelis is frequently misidentified as E. meningoseptica. Therefore, our aim was to explore the clinical and molecular differences between these two species. The database of a clinical microbiology laboratory in a university-affiliated hospital of Taiwan was searched to identify patients with Elizabethkingia infections between January 2005 and June 2018. Species were reidentified using 16S ribosomal RNA gene sequencing. Twenty E. meningoseptica and 72 E. anophelis samples were collected from consecutive patients. E. meningoseptica was significantly more frequently isolated from the cerebrospinal fluid than was E. anophelis. The most susceptible antibiotic for all Elizabethkingia isolates was minocycline (91.3%), followed by levofloxacin (52.2%), tigecycline (23.9%), and piperacillin tazobactam (23.9%). Compared with E. anophelis, E. meningoseptica was significantly less susceptible to piperacillin tazobactam, minocycline, and levofloxacin. Regarding nonsynonymous substitutions in the quinolone-resistance determining regions of DNA gyrase, six sites were recognized in E. meningoseptica and one site was recognized in E. anophelis. E. meningoseptica had a significantly higher rate of fluoroquinolone target gene mutations than did E. anophelis. Because of less susceptibility to multiple antibiotics than E. anophelis, empirical antimicrobial therapy of E. meningoseptica should be more rigorous.