Implication of genotypes for prognosis of Candida glabrata bloodstream infections.

BACKGROUND: Genotyping isolates of a specific pathogen may demonstrate unique patterns of antimicrobial resistance, virulence or outcomes. However, evidence for genotype-outcome association in Candida glabrata is scarce. We aimed to characterize the mycological and clinical relevance of genotypes on C. glabrata bloodstream infections (BSIs). METHODS: Non-duplicated C. glabrata blood isolates from hospitalized adults were genotyped by MLST, and further clustered by the unweighted pair group method with arithmetic averages (UPGMA). A clonal complex (CC) was defined by UPGMA similarities of >90%. Antifungal susceptibility testing was performed by a colorimetric microdilution method and interpreted following CLSI criteria. RESULTS: Of 48 blood isolates evaluated, 13 STs were identified. CC7 was the leading CC (n = 14; 29.2%), including 13 ST7. The overall fluconazole and echinocandin resistance rates were 6.6% and 0%, respectively. No specific resistance patterns were associated with CC7 or other CCs. Charlson comorbidity index (adjusted OR, 1.49; 95% CI, 1.05-3.11) was the only predictor for CC7. By multivariable Cox regression analyses, CC7 was independently associated with 28 day mortality [adjusted HR (aHR), 3.28; 95% CI, 1.31-8.23], even after considering potential interaction with neutropenia (aHR, 3.41; 95% CI, 1.23-9.42; P for interaction, 0.24) or limited to 34 patients with monomicrobial BSIs (aHR, 2.85; 95% CI, 1.15-7.08). Also, the Kaplan-Meier estimate showed greater mortality with CC7 (P = 0.003). Fluconazole resistance or echinocandin therapy had no significant impact on mortality. CONCLUSIONS: Our data suggested comorbid patients were at risk of developing CC7 BSIs. Further, CC7 was independently associated with worse outcomes.

Higher serologic responses of early syphilis to single-dose benzathine penicillin G plus doxycycline versus single-dose benzathine penicillin G alone among people with HIV.

BACKGROUND: Single-dose benzathine penicillin G (BPG) is the preferred therapy for early syphilis, but poorer serologic responses have been observed among people with HIV (PWH). No enhanced regimen has previously been shown to improve serologic outcomes of early syphilis. METHODS: We conducted a retrospective study to compare the treatment responses to single-dose BPG combined with 7-day doxycycline versus BPG alone in PWH who presented with early syphilis. Rapid plasma reagin (RPR) titers were determined every 3-6 months for all included PWH. Serologic response was defined as at least a fourfold decline in RPR titers at month 12. RESULTS: During January 2018 to March 2022, 223 PWH with 307 episodes of early syphilis received single-dose BPG plus doxycycline and 347 PWH with 391 episodes received BPG alone. The median age was 36 years and baseline CD4 count was 600 cells/mm3. In the intention-to-treat with last-observation-carried-forward analysis, PWH receiving BPG plus doxycycline had a significantly higher serologic response rate at 12 months of treatment than those receiving BPG alone (79.5% vs 70.3%, respectively; P= .006). The factors associated with 12-month serologic response were RPR titer (per 1-log2 increase, adjusted odds ratio [AOR], 1.25; 95% CI, 1.15-1.35) and receipt of BPG plus doxycycline (AOR, 1.71; 95% CI, 1.20-2.46). In the subgroup analyses, BPG plus doxycycline was consistently associated with a better serologic response than BPG alone at month 12. CONCLUSIONS: Among PWH with early syphilis, single-dose BPG plus doxycycline achieved higher serologic responses than BPG alone during a 12-month follow-up period.

A Randomized Clinical Trial of 1-Dose vs Accelerated 2-Dose Schedule for Hepatitis A Virus (HAV) Revaccination Among People With Human Immunodeficiency Virus Who Were Nonresponders or Had Seroreversion After Primary HAV Vaccination.

BACKGROUND: For people with human immunodeficiency virus (PWH) who have no serological responses to their primary hepatitis A virus (HAV) vaccination or have seroreversion after successful primary vaccination, the optimal revaccination strategy remains unclear. METHODS: In this open-label, randomized clinical trial, PWH who tested negative for anti-HAV antibodies after receiving a standard 2-dose series of primary HAV vaccination were enrolled and assigned in a 1:1 ratio to receive either 1 dose (the 1-dose group) or 2 doses of HAV vaccine administered 4 weeks apart (the 2-dose group). Serological response rates and anti-HAV antibody titers were compared at weeks 24 and 48. RESULTS: Of the 153 participants (77 in the 1-dose group and 76 in the 2-dose group), the overall serological response rates at week 48 after revaccination were similar between the 2 groups (2- vs 1-dose, 80.2% vs 71.4%, P = .20). However, anti-HAV antibody titers were consistently higher in the 2-dose group than in the 1-dose group. In subgroup analysis, PWH who were nonresponders to primary HAV vaccination were significantly more likely to mount a serological response after 2-dose HAV revaccination (68.4% vs 44.1%, P = .038). No severe adverse events were reported throughout the study. CONCLUSIONS: Two-dose HAV revaccination administered 4 weeks apart yielded similar serological responses as 1-dose revaccination among PWH who were nonresponders or had seroreversion after primary HAV vaccination. The 2-dose revaccination schedule generated significantly higher anti-HAV antibody titers and was more likely to elicit serological responses at week 48 among PWH who were nonresponders to primary HAV vaccination. Clinical Trials Registration. NCT03855176.

Influence of daptomycin dose and fosfomycin susceptibility on outcome of vancomycin-resistant Enterococcus faecium bloodstream infections treated with daptomycin and fosfomycin combination.

OBJECTIVES: Synergistic combinations of daptomycin and ß-lactam antibiotics are currently recommended for treatment of VRE bloodstream infection (BSI). The efficacy of these combinations is jeopardized by VRE inherently resistant to ß-lactam antibiotics. The combination of daptomycin and fosfomycin is recommended as an alternative therapy for VRE BSI; however, clinical data to support use of this combination are lacking. PATIENTS AND METHODS: We conducted a prospective observational multicentre study of patients treated with a combination of daptomycin and fosfomycin for VRE BSI during 2016-20. The primary outcome was 28 day mortality. Multivariable logistic regression was performed for outcome analysis. RESULTS: The study included 106 patients from 1112 VRE BSI episodes. The overall 28 day mortality was 40.6%. The median (IQR) daptomycin dose was 10.18 mg/kg (9.43-10.70). The fosfomycin dose was 16 g/day (8-22.5). Ninety-six isolates were available for MIC testing. The fosfomycin MIC was 32 mg/L in 6 (6.3%), 64 mg/L in 68 (70.8%) and ≥128 mg/L in 22 (22.9%) isolates. Independent of Charlson comorbidity index and Pitt bacteraemia score, fosfomycin MIC ≥128 mg/L [adjusted OR (aOR) = 3.05; 95% CI = 1.01-9.19; P = 0.047] and daptomycin dose (aOR = 0.64; 95% CI = 0.43-0.97; P = 0.04) predicted mortality. CONCLUSIONS: Higher daptomycin dose and susceptibility to fosfomycin were independently associated with lower mortality in patients with VRE BSI. Our results suggest that higher doses of daptomycin are indicated for VRE BSI, whether or not it is used in combination with fosfomycin. The combination was less effective for patients with fosfomycin-resistant isolates.

Influence of daptomycin doses on the outcomes of VRE bloodstream infection treated with high-dose daptomycin.

OBJECTIVES: The CLSI recommended high-dose daptomycin (8-12 mg/kg) for treating Enterococcus faecium bloodstream infections (BSI). The current study was designed to determine the safety and efficacy of increasing the daptomycin dose for VRE BSI patients receiving ≥8 mg/kg. METHODS: We conducted a multicentre prospective observational study of patients who received a ≥8 mg/kg dose of daptomycin for treatment of VRE BSI. The primary outcome was 28 day mortality. RESULTS: A total of 661 patients were included. The 28 day mortality rate was 45.1%. The survivors received higher doses of daptomycin than non-survivors (10.1 versus 9.8 mg/kg; P < 0.001). An increase in the daptomycin dose independently predicted lower mortality [adjusted OR (aOR) = 0.85; 95% CI = 0.73-0.99; P = 0.03]. Eighty-six survivors (23.7%) and 43 non-survivors (14.4%) received a ≥11 mg/kg dose of daptomycin (P = 0.003). The 8 to <11 and ≥11 mg/kg doses of daptomycin differed in the 28 day mortality in the higher MIC group (≥2 mg/L) (49.4% versus 33.3%; P = 0.004), but not in the lower MIC group (≤1 mg/L) (29.3% versus 29.4%; P = 0.99). A dose of ≥11 mg/kg was associated with a higher (3.9%) rate of highly elevated creatine kinase (>2000 U/L) compared with 1.1% with 8 to <11 mg/kg (P = 0.04). CONCLUSIONS: The efficacy of daptomycin is dose dependent. A high daptomycin dose, especially at ≥11 mg/kg, improved survival in patients with VRE BSI, but was associated with highly elevated creatine kinase. We recommend a ≥11 mg/kg dose of daptomycin be considered for treatment of VRE BSI, particularly for isolates with higher MICs.

Healthcare-associated carbapenem-resistant Klebsiella pneumoniae bloodstream infections: Risk factors, mortality, and antimicrobial susceptibility, 2017-2019.

BACKGROUND: In Taiwan, carbapenem-resistant Klebsiella pneumoniae (CRKP) now became a leading cause of difficult-to-treat healthcare-associated infection, for which there are a lack of recent hospital epidemiological studies on risk factors, mortality, and antimicrobial susceptibility. METHODS: We prospectively enrolled patients with healthcare-associated CRKP monomicrobial bloodstream infection (mBSI) and matched patients with carbapenem susceptible K. pneumoniae (CSKP) mBSI at National Taiwan University Hospital (Taipei, Taiwan) from October 2017 through December 2019 in a 1:2 ratio. Multivariable logistic regression and Kaplan-Meier analyses were applied to identify factors associated with CRKP mBSI and to compare the 14-day survival curves, respectively. We detected the presence of blaKPC and blaNDM gene among the included CRKP strains, and performed antimicrobial susceptibility testing (including susceptibility to colistin, aminoglycoside, tigecycline, and ceftazidime/avibactam). RESULTS: A total of 36 CRKP cases and 72 CSKP controls were enrolled. Patients with CRKP mBSI were more likely to have liver cirrhosis (adjusted odds ratio [aOR], 5.61; P = 0.024), length of hospital stay over the previous 14 days (aOR, 1.23; P = 0.001) and prior use of carbapenems in the previous 14 days (aOR, 6.07; P = 0.004) than patients with CSKP mBSI. The 14-day survival was significantly worse for patients with CRKP mBSI than those with CSKP mBSI (all CRKP cases: 50.0% vs. 87.5%; P < 0.001; CRKP cases treated with colistin as an appropriate backbone antibiotic: 58.3% vs. 87.5%; P = 0.007). Compared with the CSKP isolates, CRKP isolates were significantly less susceptible to colistin, amikacin, and tigecycline. Of the 36 CRKP isolates, none harbor blaNDM gene and 35 (97%) had low minimum inhibitory concentrations (≤8/4 µg/ml) of ceftazidime/avibactam by the E test method. CONCLUSION: Prior exposure to carbapenems, longer hospital stay, and the presence of liver cirrhosis predicted CRKP instead of CSKP mBSI. Even with colistin therapy, CRKP mBSIs was still associated with a very high risk of mortality within 14 days. Ceftazidime/avibactam is a potentially useful therapeutic choice for cases caused by in vitro susceptible CRKP strains.

High prevalence of sexually transmitted coinfections among at-risk people living with HIV.

BACKGROUND/PURPOSE: Concurrent sexually transmitted infections (STIs) are not uncommon in at-risk populations, for which control requires integrated testing, treatment and prevention. METHODS: From May, 2019 to February, 2020, multiplex real-time PCR assays were prospectively performed to detect Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Trichomonas vaginalis (TV) in the urine and rectal/vaginal swab specimens collected from HIV-positive patients with a history of STIs or symptoms suggestive of STIs. Patients confirmed to have acquired STIs were treated according to treatment guidelines. RESULTS: During the study period, 430 participants (99.1% men who have sex with men and median age 37 years) were included. The overall prevalence of CT, NG, and/or TV infection was 30.0%, including 24.7%, 12.1%, and 0.2% for CT, NG, and TV infection, respectively. The factors associated with CT, NG, and/or TV infection were hepatitis B surface antigen (HBsAg) seropositivity (AOR, 2.76; 95% CI, 1.22-6.26), recently acquired hepatitis C virus (HCV) infection (AOR, 5.62; 95% CI, 1.99-15.88), using mobile dating application (AOR, 2.08; 95% CI, 1.13-3.83), and oral sex (AOR, 2.12; 95% CI, 1.04-4.32). The rates of CT, NG, and/or TV infection were 50.0% in participants with recent HCV infection, 44.2% in those with HBsAg positivity, and 35.9% in those with incident syphilis. Among participants completing test-of-cure visits, the microbiological cure rate was 91.7% and 90.0% for chlamydia and gonorrhea, respectively. CONCLUSION: HIV-positive participants had a high prevalence of CT and/or NG, especially those coinfected with viral hepatitis and syphilis. Our results strongly support integrated STI services in the population.

Effect of a Hepatitis A Vaccination Campaign During a Hepatitis A Outbreak in Taiwan, 2015-2017: A Modeling Study.

BACKGROUND: Beginning from 2015-2016, unprecedented large outbreaks of acute hepatitis A that predominantly affected men who have sex with men (MSM) reemerged across the continents. We assessed the impact of an early initiated hepatitis A virus (HAV) vaccination campaign that targeted MSM living with human immunodeficiency virus (HIV) during the 2015-2017 hepatitis A outbreak in Taiwan. METHODS: First, we ascertained the effectiveness of HAV vaccination for MSM living with HIV using a nested case-control study of 1470 persons living with HIV who were initially HAV-seronegative. We then fitted a model of HAV transmission among MSM, risk-structured by HIV status, to the actual epidemic curve of reported acute hepatitis A cases in Taiwan during 2015-2017. RESULTS: Fifty-five cases of acute hepatitis A were matched to 220 controls. Single-dose and 2-dose HAV vaccination provided protection rates of 96.1% and 97.8% among recipient MSM living with HIV, respectively. Model fitting yielded basic reproductive number estimates of 7.26 (MSM living with HIV) and 3.04 (MSM not living with HIV). In a counterfactual scenario without an HAV vaccination campaign, the outbreak would have involved 7153 hepatitis A cases during 2015-2017 in contrast to the 1352 that were observed. We therefore estimated that the HAV vaccination campaign averted 80.7% (sensitivity analysis, 48.8%-92.7%) of acute hepatitis A cases that would otherwise have occurred by the end of 2017. CONCLUSIONS: The early initiated HAV vaccination campaign, which targeted MSM living with HIV, very effectively curtailed the 2015-2017 hepatitis A outbreak in Taiwan.

Impact of archived M184V/I mutation on the effectiveness of switch to co-formulated elvitegravir, cobicistat, emtricitabine and tenofovir alafenamide among virally suppressed people living with HIV.

OBJECTIVES: Real-world experience regarding the effectiveness of co-formulated elvitegravir, cobicistat, emtricitabine and tenofovir alafenamide (EVG/C/FTC/TAF) as a switch regimen is sparse among people living with HIV (PLWH) harbouring the M184V/I mutation with or without thymidine analogue-associated mutations (TAMs). METHODS: In this retrospective multicentre study, PLWH who were switched to EVG/C/FTC/TAF after having achieved viral suppression (plasma HIV RNA <200 copies/mL) for 6 months or longer were included. Patients with archived M184V/I mutation (case patients) were matched to controls without M184V/I mutation at a 1:4 ratio. Patients with a history of virological failure or resistance to elvitegravir were excluded. The primary endpoint was virological non-success (plasma HIV RNA ≥50 copies/mL) at Week 48 of switch using a modified FDA snapshot analysis. RESULTS: Overall, 100 case patients with the M184V/I mutation were identified, including 6 (6.0%) with K65R and 13 (13.0%) with at least one TAM, and were matched to 400 controls in terms of gender, age (mean = 40.3 versus 39.7 years) and cumulative exposure duration to tenofovir disoproxil fumarate (median = 146 versus 143 weeks). At Week 48, the rate of virological non-success for the case patients and controls was 5.0% (5/100) and 3.3% (13/400), respectively (difference = 1.7%; 95% CI = -2.9%-6.3%), while the rate of virological success was 88.0% and 89.5% for the case patients and controls, respectively. The presence of the K65R mutation or TAMs was not associated with virological non-response. CONCLUSIONS: Among virally suppressed PLWH, EVG/C/FTC/TAF is effective in maintaining viral suppression at Week 48 despite archived M184V/I mutation with or without TAMs.

The origin of GSKIP, a multifaceted regulatory factor in the mammalian Wnt pathway.

GSK3ß interacting protein (GSKIP) is a naturally occurring negative regulator of GSK3ß and retains both the Protein Kinase A Regulatory subunit binding (PKA-RII) domain and GSK3ß interacting domain. Of these two domains, we found that PKA-RII is required for forming a working complex comprising PKA/GSKIP/GSK3ß/Drp1 to influence phosphorylation of Drp1 Ser637. In this study, bioinformatics and experimental explorations re-analyzing GSKIP's biofunctions suggest that the evolutionarily conserved Domain of Unknown Function (DUF727) is an ancestral prototype of GSKIP in prokaryotes, and acquired the C-terminal GSK3ß binding site (tail) in invertebrates except for Saccharomyces spp., after which the N-terminal PKA-RII binding region (head) evolved in vertebrates. These two regions mutually influence each other and modulate GSKIP binding to GSK3ß in yeast two-hybrid assays and co-immunoprecipitation. Molecular modeling showed that mammalian GSKIP could form a dimer through the L130 residue (GSK3ß binding site) rather than V41/L45 residues. In contrast, V41/L45P mutant facilitated a gain-of-function effect on GSKIP dimerization, further influencing binding behavior to GSK3ß compared to GSKIP wild-type (wt). The V41/L45 residues are not only responsible for PKA RII binding that controls GSK3ß activity, but also affect dimerization of GSKIP monomer, with net results of gain-of-function in GSKIP-GSK3ß interaction. In addition to its reported role in modulating Drp1, Ser637 phosphorylation caused mitochondrial elongation; we postulated that GSKIP might be involved in the Wnt signaling pathway as a scavenger to recruit GSK3ß away from the ß-catenin destruction complex and as a competitor to compete for GSK3ß binding, resulting in accumulation of S675 phosphorylated ß-catenin.

Clonality of Fluconazole-Nonsusceptible Candida tropicalis in Bloodstream Infections, Taiwan, 2011-2017.

Candida tropicalis is the leading cause of non-C. albicans candidemia in tropical Asia and Latin America. We evaluated isolates from 344 patients with an initial episode of C. tropicalis candidemia. We found that 58 (16.9%) patients were infected by fluconazole-nonsusceptible (FNS) C. tropicalis with cross resistance to itraconazole, voriconazole, and posaconazole; 55.2% (32/58) of patients were azole-naive. Multilocus sequence typing analysis revealed FNS isolates were genetically closely related, but we did not see time- or place-clustering. Among the diploid sequence types (DSTs), we noted DST225, which has been reported from fruit in Taiwan and hospitals in Beijing, China, as well as DST376 and DST505-7, which also were reported from hospitals in Shanghai, China. Our findings suggest cross-boundary expansion of FNS C. tropicalis and highlight the importance of active surveillance of clinical isolates to detect dissemination of this pathogen and explore potential sources in the community.

Serologic responses and effectiveness of hepatitis A vaccination among human immunodeficiency virus-positive individuals during the outbreak of acute hepatitis A.

Outbreaks of hepatitis A virus (HAV) infection have been occurring among men who have sex with men in the Asia-Pacific region, the United States, and several European countries since June 2015 and recently among persons who are homeless and use illicit drugs in the United States. We evaluated the serologic responses and effectiveness of HAV vaccination in human immunodeficiency virus (HIV)-positive individuals during the outbreak in Taiwan. From June 1, 2015, to September 30, 2016, anti-HAV immunoglobulin G was prospectively determined among all HIV-positive individuals. We prospectively observed 1,533 HAV-seronegative, HIV-positive individuals (94.1% being men who have sex with men with a median cluster of differentiation 4 (CD4) count of 550 cells/µL) who were advised to receive two doses of HAV vaccine administered 6 months apart. Of them, 1,001 individuals (65.3%) received at least one dose of HAV vaccine during the study period and 532 (34.7%) declined to receive vaccine. The primary endpoints were serologic response at weeks 28-36 and acquisition of HAV infection during follow-up. The incidence rate of acute HAV infection was 3.7 and 99.3 per 1,000 person-years of follow-up in the vaccinated and unvaccinated groups, respectively, resulting in a vaccine effectiveness of 96.3%. At weeks 28-36, the seroconversion rates were 63.8% and 93.7% in the intention-to-treat and per-protocol analyses, respectively. The factors associated with seroconversion at weeks 28-36 were younger age (per 1-year decrease, adjusted odds ratio, 1.08; 95% confidence interval, 1.02-1.12) and undetectable plasma HIV RNA load (adjusted odds ratio, 3.19; 95% confidence interval, 1.32-7.68). CONCLUSION: During the outbreak of acute hepatitis A, two-dose HAV vaccination is effective at preventing HAV infection among HIV-positive individuals receiving combination antiretroviral therapy; our data highlight the importance of HAV serologic screening and vaccination to prevent outbreaks of acute hepatitis A in at-risk populations. (Hepatology 2018;68:22-31).

Impact of antiretroviral therapy containing tenofovir disoproxil fumarate on the survival of patients with HBV and HIV coinfection.

BACKGROUND: Tenofovir disoproxil fumarate (TDF) is active against both HBV and HIV. Whether the introduction of TDF-containing combination antiretroviral therapy (cART) has improved the outcome of HIV/HBV-coinfected patients remains unclear in areas of higher HBV endemicity. METHODS: We retrospectively reviewed medical records of newly diagnosed antiretroviral-naïve HIV-infected patients between 2007 and 2015. Four groups of patients were defined, according to the HBV status and availability of TDF for HIV treatment in Taiwan in 2011. The primary outcome was all-cause mortality. RESULTS: During the 9-year study period, 1,723 HIV-infected patients were included, with a median age of 31 years and baseline CD4 count of 273 cells per µL. The HBV seroprevalence had declined from 18.1% (125/692) in the pre-TDF era to 10.1% (104/1031) in the post-TDF era. The respective mortality rate for HIV/HBV-coinfected and HIV-monoinfected patients in the pre-TDF era was 23.2 (95% CI, 12.5-43.1) and 9.6 (95% CI, 6.1-15.0) deaths per 1000 person-years of follow-up [PYFU], and the respective mortality rate in the post-TDF era was 15.7 (95% CI, 7.0-34.8) and 8.0 (95% CI, 5.5-11.6) deaths per 1000 PYFU. The adjusted hazard ratio for mortality in multivariate Cox proportional-hazards regression analysis among HIV/HBV-coinfected patients compared to HIV-monoinfected patients was 2.79 (95% CI, 1.25-6.22) in pre-TDF era and 1.11 (95% CI, 0.45-2.72) in post-TDF era. CONCLUSIONS: In this country of high HBV endemicity, the adverse impact of chronic HBV infection on the survival observed in the pre-TDF era has significantly diminished among HIV/HBV-coinfected patients compared to HIV-monoinfected patients in the era of TDF-containing cART.

Comparable Serologic Responses to 2 Different Combinations of Inactivated Hepatitis A Virus Vaccines in HIV-Positive Patients During an Acute Hepatitis A Outbreak in Taiwan.

We evaluated the serologic responses to different 2-dose combinations of the inactivated hepatitis A virus (HAV) vaccines Havrix and Vaqta among human immunodeficiency virus-positive individuals during an acute hepatitis A outbreak in Taiwan. In this 16-month retrospective study, one group received 1 dose of Havrix followed by 1 dose of Vaqta, and another group received 2 doses of Vaqta. The Havrix-Vaqta and Vaqta-Vaqta groups achieved similar seroconversion rates at weeks 28-36 (82.3% and 80.9%, respectively; absolute difference, 1.3% [95% confidence interval {CI}, -6.3%-3.7%]) and week 48 (94.7% and 94.4%, respectively; absolute difference, 0.3% [95% CI, -2.6%-3.2%]), suggesting the interchangeability of different combinations of HAV vaccines. The significantly higher seroconversion rate after the first dose of Vaqta, compared with the dose of Havrix (53.0% vs 32.4%) may provide potential benefits in preventing HAV infection during the outbreak.

In Vitro Evaluation of Povidone-Iodine and Chlorhexidine against Outbreak and Nonoutbreak Strains of Mycobacterium abscessus Using Standard Quantitative Suspension and Carrier Testing.

Povidone-iodine (PI) and chlorhexidine (CHX) are widely used antiseptics active against conventional Staphylococcus aureus, Enterobacteriaceae, Candida species, and viruses, but their efficacy against Mycobacterium abscessus remains unproven. We determined the in vitro potency of alcoholic PI and CHX against M. abscessus subsp. abscessus (ATCC 19977), M. abscessus subsp. bolletii (BCRC 16915), and our outbreak strain of M. abscessus subsp. massiliense (TPE 101) in reference to Staphylococcus aureus (ATCC 29213) by standard quantitative suspension and carrier methods (EN 14563). By suspension, all mycobacterial strains compared to S. aureus were significantly more resistant to CHX, but not PI. By carrier, the mean logarithmic reductions (LR) achieved by PI under clean (dirty) conditions were 6.575 (2.482), 5.540 (2.298), 4.595 (1.967), and 1.173 (0.889), while those achieved by CHX under clean (dirty) conditions were 3.164 (5.445), 5.307 (2.564), 3.844 (2.232), and 0.863 (0.389) for S. aureus, M. abscessus subsp. bolletii, M. abscessus subsp. abscessus, and M. abscessus subsp. massiliense, respectively. M. abscessus subsp. massiliense (outbreak strain) was significantly more resistant than the other tested strains to PI and CHX. By both methods, the mean LR achieved by PI was higher than for CHX for all mycobacterial strains, but under dirty conditions, neither antiseptic was effectively mycobactericidal (LR < 5). These preliminary findings caution against the universal replacement of PI with CHX as the first-line skin antiseptic, since all M. abscessus isolates were resistant to CHX. More studies are needed to establish the best practice for skin antisepsis if mycobacterial infections are also to be prevented.

Survival of Patients With Vancomycin-Resistant Enterococcus faecium Bacteremia Treated With Conventional or High Doses of Daptomycin or Linezolid Is Associated With the Rate of Bacterial Clearance.

OBJECTIVES: Vancomycin-resistant enterococci are important pathogens for healthcare-associated infections. Although linezolid is bacteriostatic and daptomycin is rapidly bactericidal against vancomycin-resistant enterococci in vitro, it is not clear whether they differ in their effect on bacterial clearance in patients with vancomycin-resistant enterococci bloodstream infections. DESIGN: Prospective observational study. SETTING: Two university hospitals and research laboratory. PATIENTS: Patients with vancomycin-resistant enterococci bloodstream infection proven by blood cultures were prospectively enrolled from January 2010 to July 2015. INTERVENTIONS: Sequential blood samples were collected. Real-time quantitative polymerase chain reaction was used to monitor bacterial loads. MEASUREMENTS AND MAIN RESULTS: One hundred eight patients with vancomycin-resistant enterococci bloodstream infection were enrolled. Quantitative polymerase chain reaction assays were performed on 465 blood isolates. We found this method to be closely correlated with colony-forming units and more sensitive than culture. Sixty-three patients (58.3%) received "conventional dose" daptomycin (6-9 mg/kg), 15 (13.9%) received high-dose daptomycin (≥ 9 mg/kg), and 30 (27.8%) were treated with linezolid (600 mg every 12 hr) as sole agents. The initial mean bacterial load was 1.03 log10 copies/mL and unrelated to survival. Survivors had a more rapid early bacterial clearance than nonsurvivors (Δ log10 copies/mL/d; -0.16 vs 0.31; p = 0.02). Multivariable logistic regression showed that a slower early bacterial clearance independently predicted increased mortality (odds ratio, 3.21; 95% CI, 1.03-10.02; p = 0.045). Conventional dose daptomycin was associated with a significantly slower rate of bacterial clearance than high-dose daptomycin (Δ log10 copies/mL/d; -0.04 vs -0.41; p < 0.001) and linezolid (-0.04 vs -0.56; p = 0.043). CONCLUSIONS: We found that survivors of vancomycin-resistant enterococci bloodstream infection had a significantly more rapid early bacterial clearance by quantitative polymerase chain reaction than nonsurvivors. High-dose daptomycin and linezolid were associated with more rapid bacterial clearance than conventional dose daptomycin. These results support recommendations that conventional dose daptomycin not be used for the treatment of patients with vancomycin-resistant enterococci bloodstream infection.

Molecular Modeling for Structural Insights Concerning the Activation Mechanisms of F1174L and R1275Q Mutations on Anaplastic Lymphoma Kinase.

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase involved in various cancers. In its basal state, the structure of ALK is in an autoinhibitory form stabilized by its A-loop, which runs from the N-lobe to the C-lobe of the kinase. Specifically, the A-loop adopts an inhibitory pose with its proximal A-loop helix (αAL-helix) to anchor the αC-helix orientation in an inactive form in the N-lobe; the distal portion of the A-loop is packed against the C-lobe to block the peptide substrate from binding. Upon phosphorylation of the first A-loop tyrosine (Y1278), the αAL-helix unfolds; the distal A-loop detaches from the C-lobe and reveals the P+1 pocket that accommodates the residues immediately after their phosphorylation, and ALK is activated accordingly. Recently, two neuroblastoma mutants, F1174L and R1275Q, have been determined to cause ALK activation without phosphorylation on Y1278. Notably, F1174 is located on the C-terminus of the αC-helix and away from the A-loop, whereas R1275 sits on the αAL-helix. In this molecular modeling study, we investigated the structural impacts of F1174L and R1275Q that lead to the gain-of-function event. Wild-type ALK and ALK with phosphorylated Y1278 were also modeled for comparison. Our modeling suggests that the replacement of F1174 with a smaller residue, namely leucine, moves the αC-helix and αAL-helix into closer contact and further distorts the distal portion of the A-loop. In wild-type ALK, R1275 assumes the dual role of maintaining the αAL-helix⁻αC-helix interaction in an inactive form and securing αAL-helix conformation through the D1276⁻R1275 interaction. Accordingly, mutating R1275 to a glutamine reorients the αC-helix to an active form and deforms the entire A-loop. In both F1174L and R1275Q mutants, the A-loop rearranges itself to expose the P+1 pocket, and kinase activity resumes.

Effect of Daptomycin Dose on the Outcome of Vancomycin-Resistant, Daptomycin-Susceptible Enterococcus faecium Bacteremia.

Background: Treatment options for vancomycin-resistant enterococci (VRE) bloodstream infection (BSI) are limited. Daptomycin, although not currently approved for this indication, is frequently used for the treatment of VRE-BSI. Its optimal dose still needs to be determined. Methods: We conducted a prospective, observational, cohort study during 2010-2015. We included patients who received a daptomycin dose of ≥6 mg/kg for the treatment of VRE-BSI caused by daptomycin-susceptible VRE. The primary endpoint was 14-day mortality, and multivariable logistic regression was performed for outcome analysis. Results: We included 112 patients treated with daptomycin for VRE-BSI and with evaluable clinical outcomes. The daptomycin minimum inhibitory concentration (MIC) was 4 mg/L in 78 (69.6%) and ≤2 mg/L in 34 (30.4%) isolates. The overall mortality was 40/112 (35.7%). The unadjusted mortality was 18/36 (50.0%) for a daptomycin dose of <7 mg/kg, 17/51 (33.3%) for a dose of 7-9 mg/kg, and 5/25 (20%) for a dose of ≥9 mg/kg (P = .05). The best outcomes were associated with a daptomycin dose of ≥9 mg/kg compared to doses of <7 mg/kg (adjusted odds ratio [aOR], 10.57; 95% confidence interval [CI], 2.25-49.62; P=.003) and 7-9 mg/kg (aOR, 5.01; 95% CI, 1.14-21.98; P=.03). There was no significant difference in mortality with respect to the daptomycin MIC. There was no association between daptomycin dose and elevated creatinine kinase. Conclusion: Higher daptomycin doses (≥9 mg/kg) were associated with lower mortality in patients with VRE-BSI. Our results suggest that higher daptomycin doses need to be considered for VRE-BSI treatment.

Excess Mortality Associated With Colistin-Tigecycline Compared With Colistin-Carbapenem Combination Therapy for Extensively Drug-Resistant Acinetobacter baumannii Bacteremia: A Multicenter Prospective Observational Study.

OBJECTIVES: Since few therapeutic options exist for extensively drug resistant Acinetobacter baumannii, an emerging threat in ICUs worldwide, and comparative prospective studies of colistin-based combination therapies are lacking, our objective was to compare the outcomes of patients with extensively drug-resistant A. baumannii bacteremia, treated with colistin-carbapenem and colistin-tigecycline combinations. DESIGN: Prospective, observational, multicenter study. SETTING, PATIENTS, AND INTERVENTIONS: Adults with extensively drug-resistant A. baumannii bacteremia were prospectively followed from 2010 to 2013 at three hospitals in Taiwan. Extensively drug-resistant A. baumannii was defined as A. baumannii (genospecies 2) nonsusceptible to all drug classes except for colistin and tigecycline, and standard combination therapy as use of parenteral colistin-carbapenem or colistin-tigecycline for at least 48 hours after onset of bacteremia. MEASUREMENTS AND MAIN RESULTS: Primary outcome measure was 14-day mortality. Of the 176 episodes of extensively drug-resistant A. baumannii bacteremia evaluated, 55 patients with a median (interquartile range) age of 62 years (44-79 yr) and Sequential Organ Failure Assessment score of 9 (5-13) points received standard combination therapy: colistin-tigecycline in 29 patients and colistin-carbapenem in 26. Crude 14-day and in-hospital mortality rates for patients receiving colistin-tigecycline versus patients receiving colistin-carbapenem were 35% versus 15% (p=0.105) and 69% versus 50% (p=0.152), respectively. Breakthrough extensively drug-resistant A. baumannii bacteremia under steady state concentrations of combination therapy for colistin-tigecycline group was 18% and for colistin-carbapenem group was 0% (p=0.059). Eleven patients (20.0%) developed nephrotoxicity. After adjusting for age, sex, comorbidity, initial disease severity, loading colistin dose, polymicrobial infection, and primary infection site, excess 14-day mortality was associated with the use of colistin-tigecycline in the subgroup with tigecycline minimum inhibitory concentration greater than 2 mg/L compared with the use of colistin-carbapenem (hazard ratio, 6.93; 95% CI, 1.61-29.78; p=0.009). CONCLUSIONS: Increased 14-day mortality was associated with colistin-tigecycline therapy given tigecycline minimum inhibitory concentration greater than 2 mg/L compared with colistin-carbapenem therapy for extensively drug-resistant A. baumannii bacteremia.