A Novel Structure Fusion Attention Model to Detect Architectural Distortion on Mammography.

Architectural distortion (AD) is one of the most common findings on mammograms, and it may represent not only cancer but also a lesion such as a radial scar that may have an associated cancer. AD accounts for 18-45% missed cancer, and the positive predictive value of AD is approximately 74.5%. Early detection of AD leads to early diagnosis and treatment of the cancer and improves the overall prognosis. However, detection of AD is a challenging task. In this work, we propose a new approach for detecting architectural distortion in mammography images by combining preprocessing methods and a novel structure fusion attention model. The proposed structure-focused weighted orientation preprocessing method is composed of the original image, the architecture enhancement map, and the weighted orientation map, highlighting suspicious AD locations. The proposed structure fusion attention model captures the information from different channels and outperforms other models in terms of false positives and top sensitivity, which refers to the maximum sensitivity that a model can achieve under the acceptance of the highest number of false positives, reaching 0.92 top sensitivity with only 0.6590 false positive per image. The findings suggest that the combination of preprocessing methods and a novel network architecture can lead to more accurate and reliable AD detection. Overall, the proposed approach offers a novel perspective on detecting ADs, and we believe that our method can be applied to clinical settings in the future, assisting radiologists in the early detection of ADs from mammography, ultimately leading to early treatment of breast cancer patients.

The effect of oral antiviral therapy for COVID-19 in managing non-hospitalized patients with lung cancer.

BACKGROUNDS: The effectiveness of oral antiviral therapy including nirmatrelvir plus ritonavir and molnupiravir in managing COVID-19 among individuals with pre-existing lung cancer was unclear. Therefore, this study was conducted to evaluate the usefulness of antiviral agents in the management of COVID-19 among patients with lung cancer. METHODS: Utilizing data from the TriNetX - a global health research network, a retrospective cohort study was conducted involving 2484 patients diagnosed with both lung cancer and COVID-19. Propensity score matching (PSM) was employed to create well-balanced cohorts. The study assessed the primary outcome of all-cause hospitalization or mortality within a 30-day follow-up. RESULTS: After PSM, the oral antiviral group exhibited a significantly lower risk of the primary composite outcome compared to the control group (6.1 % vs. 9.9 %; HR: 0.60; 95 % CI: 0.45-0.80). This association was consistent across various subgroups according to age, sex, vaccine status, type of oral antiviral agent, and lung cancer characteristics. Additionally, the oral antiviral group showed a lower risk of all-cause hospitalization (HR: 0.73; 95 % CI: 0.54-0.99) and a significantly lower risk of mortality (HR: 0.16; 95 % CI: 0.06-0.41). CONCLUSION: The study suggests a favorable impact of oral antiviral therapy on the outcomes of COVID-19 in individuals with lung cancer and support the potential utility of oral antiviral agents in improving outcomes in this vulnerable population.

Malnutrition and the Post-Acute Sequelae of Severe Acute Respiratory Syndrome Coronavirus 2 Infection: A Multi-Institutional Population-Based Propensity Score-Matched Analysis.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to a global health crisis, exacerbating issues like malnutrition due to increased metabolic demands and reduced intake during illness. Malnutrition, a significant risk factor, is linked to worse outcomes in patients with COVID-19, such as increased mortality and extended hospital stays. This retrospective cohort study investigated the relationship between malnutrition and clinical outcomes within 90-180 days using data obtained from the TriNetX database. Patients aged >18 years diagnosed with COVID-19 between 1 January 2022, and 31 March 2024 were enrolled in the study. The propensity score-matching (PSM) method was used to match patients with malnutrition (malnutrition group) and those without malnutrition (control group). The primary composite outcome was the cumulative hazard ratio (HR) for post-COVID-19 condition, all-cause hospitalization, and all-cause mortality between 90 days and 180 days after COVID-19 diagnosis. The secondary outcomes were the individual components of the primary outcomes. Two cohorts, each consisting of 15,004 patients with balanced baseline characteristics, were identified using PSM. During the 90-180-day follow-up period, the malnutrition group exhibited a higher incidence of all-cause hospitalization, mortality, or post-COVID-19 condition (HR = 2.315, 95% confidence interval: 2.170-2.471, p < 0.0001). Compared with patients with COVID-19 without malnutrition, those with malnutrition may be associated with a higher risk of adverse clinical outcomes.

In vitro efficacies and resistance profiles of rifampin-based combination regimens for biofilm-embedded methicillin-resistant Staphylococcus aureus.

To compare the in vitro antibacterial efficacies and resistance profiles of rifampin-based combinations against methicillin-resistant Staphylococcus aureus (MRSA) in a biofilm model, the antibacterial activities of vancomycin, teicoplanin, daptomycin, minocycline, linezolid, fusidic acid, fosfomycin, and tigecycline alone or in combination with rifampin against biofilm-embedded MRSA were measured. The rifampin-resistant mutation frequencies were evaluated. Of the rifampin-based combinations, rifampin enhances the antibacterial activities of and even synergizes with fusidic acid, tigecycline, and, to a lesser extent, linezolid, fosfomycin, and minocycline against biofilm-embedded MRSA. Such combinations with weaker rifampin resistance induction activities may provide a therapeutic advantage in MRSA biofilm-related infections.

Clinical outcomes, virological efficacy and safety of nitazoxanide in the treatment of patients with COVID-19: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: This study investigated the clinical outcomes, virological efficacy and safety of nitazoxanide in the treatment of patients with COVID-19. RESEARCH DESIGN AND METHODS: The PubMed, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov databases were searched for relevant articles written before August 23, 2022. Only randomized controlled trials (RCTs) that assessed the usefulness and safety of nitazoxanide in patients with COVID-19 were included. RESULTS: Five RCTs were included. The overall mortality of COVID-19 patients receiving nitazoxanide (study group) was 1.3% (9/670), which was lower than the control group (1.8%, 12/681), but this difference did not reach statistical significance (risk difference [RD], 0.00; 95% CI: -0.01 to 0.01; P =0.97). However, nitazoxanide was associated with a higher virological eradication rate than placebo or standard care (RD, 0.09; 95% CI: 0.01 to 0.17; P = 0.03). Compared with the placebo or standard care, nitazoxanide were associated with a similar risk of any adverse event (RD, -0.02; 95% CI: -0.07 to 0.03; P = 0.44). CONCLUSIONS: Although nitazoxanide can help virological eradication and is also tolerable, it does not provide additional clinical benefits. Based on these evidences, the use of nitazoxanide in the treatment of patients with COVID-19 is not recommended.

The Impact of Hepatitis C Virus, Metabolic Disturbance, and Unhealthy Behavior on Chronic Kidney Disease: A Secondary Cross-Sectional Analysis.

BACKGROUND: Hepatitis C virus (HCV) infection is associated with a higher risk of chronic kidney disease (CKD). This study investigates the relationship among HCV, CKD, and understudied confounders, such as unhealthy behaviors and metabolic disturbances. METHODS: This cross-sectional study was conducted as part of a community health promotion program in an HCV endemic area of Taiwan from June to December 2019. Multivariable logistic regression analyses adjusted for demographic and clinical characteristics were performed to investigate the association between CKD and HCV seropositivity. RESULTS: Of 2387 participants who underwent health check-ups, the mean age was 64.1 years old; females predominated (63.2%), and 306 (12.8%) subjects were seropositive for HCV. CKD, defined as a lower estimated glomerular filtration rate (eGFR) was associated with unhealthy dietary habits, metabolic syndrome, and HCV. Less frequent exercise, higher waist circumference (WC) and HbA1c all affected risk of CKD; HCV increased risk of CKD by 44% compared to non-HCV (OR 1.44, 95% confidence interval (CI) 1.05-1.98) in the multivariable analysis. In the HCV group, lower eGFR was also significantly associated with the severity of metabolic syndrome (MetS) (median eGFR was 86.4, 77.1, and 64.5 mL/min/1.73 m2 for individuals with three and five MetS components, respectively). CONCLUSIONS: Beyond metabolic disturbance and irregular exercise, HCV seropositivity is independently associated with CKD in a community survey. Healthy lifestyle promotion might protect against renal function decline in HCV; however, the mechanisms underlying the association need further large-scale investigation.

In vitro and in vivo intracellular killing effects of tigecycline against clinical nontyphoid Salmonella isolates using ceftriaxone as a comparator.

Salmonella is an important, worldwide food-borne pathogen. Resistance to fluoroquinolones and cephalosporins has been increasingly reported, and new therapeutic agents are desperately needed. In this study, we evaluated the in vitro antimicrobial susceptibility of clinical nontyphoidal Salmonella isolates to tigecycline. Antibacterial activity of tigecycline, ceftriaxone, and ciprofloxacin were investigated by time-kill studies and the murine peritonitis model. The MIC50/MIC90 values of tigecycline, ceftriaxone, and ciprofloxacin against 76 Salmonella isolates were 0.25/0.5, 1/8, and 0.125/0.5 µg/ml, respectively. The intracellular inhibitory activity of tigecycline at 0.5 µg/ml (1 × MIC) against Salmonella isolates in human peripheral blood mononuclear cells was sustained for 24 h. In a mouse peritonitis model, tigecycline reduced the extracellular and intracellular bacterial counts from 107 CFU/ml and 105 CFU/ml, respectively, to an undetectable level within 96 h. The results were similar to those obtained with ceftriaxone. The survival rate of mice exposed to tigecycline after being infected by an inoculum of 1 × 105 CFU was 80%, and that of mice exposed to ceftriaxone was 100%. When the inoculum was increased to 1.3 × 106 CFU, the survival rate of mice treated by tigecycline was 20%, and that of mice exposed to ceftriaxone was 0% (P = 0.2). When a ceftriaxone- and ciprofloxacin-resistant but tigecycline-susceptible isolate was tested, mice treated by tigecycline had a higher survival rate than those treated by ceftriaxone (15/20 [75%] versus 6/20 [30%]; P = 0.011). Our results suggest that tigecycline is at least as effective as ceftriaxone for murine Salmonella infections and warrants further clinical investigations to delineate its potential against human Salmonella infections.

Prevalence of Geriatric Syndromes and the Need for Hospice Care in Older Patients of the Emergency Department: A Study in an Asian Medical Center.

BACKGROUND: The prevalence of geriatric syndromes and the need for hospice care in the emergency department (ED) in Asian populations remain unclear. This study was conducted to fill the data gap. METHODS: Using a newly developed emergency geriatric assessment (EGA), we investigated the prevalence of geriatric syndromes and the need for hospice care in older ED patients of a tertiary medical center between September 1, 2016, and January 31, 2017. RESULTS: We recruited a total of 693 patients with a mean age of 78.0 years (standard deviation 8.2 years), comprising 46.6% of females. According to age subgroups, 37.4% of patients were aged 65-74 years, 37.4% were aged 75-84 years, and 25.2% were aged ≥85 years. The prevalence rates of geriatric syndromes were as follows: delirium (11.4%), depression (23.4%), dementia (43.1%), deterioration of activities of daily living (ADL) for <1 year (29.4%), vision impairment (22.2%), hearing impairment (23.8%), sleep disturbance (13.1%), any fall in <1 year (21.8%), polypharmacy (28.7%), pain (35.1%), pressure ulcer (5.6%), incontinence or retention (29.6%), indwelling device or physical restrain (21.6%), nutrition problem (35.7%), frequent use of medical resources (50.1%), lack of advance care planning (84.0%), caregiver problem (4.6%), socioeconomic problem (5.5%), and need for family meeting (6.2%). The need for hospice care was 11.9%. Most geriatric syndromes increased with advancing age except depression, sleep disturbance, polypharmacy, pain, nutrition problem, lack of advance care planning, caregiver problem, and socioeconomic problem. CONCLUSION: Geriatric syndromes and the need for hospice care were common in the older ED patients. Further studies about subsequent intervention for improving geriatric care are needed.

The Microbiological Characteristics of Carbapenem-Resistant Enterobacteriaceae Carrying the mcr-1 Gene.

OBJECTIVES: This study aims to assess the prevalence of the mcr-1 gene among carbapenem-resistant Enterobacteriaceae (CRE) isolated from clinical specimens and to further investigate the clinical significance and microbiological characteristics of CRE carrying the mcr-1 gene. METHODS: Four hundred and twenty-three CRE isolates were screened for the presence of the mcr-1 gene. After identification, their clinical significance, antibiotic susceptibility, and antibiotic resistance mechanisms including the ESBL gene, carbapenemase gene, outer membrane protein (OMP), and plasmid sequencing were assessed. RESULTS: Only four (0.9%) isolates of carbapenem-resistant Escherichia coli (E. coli) were found to carry the mcr-1 gene and demonstrated different pulsed-field gel electrophoresis (PFGE) patterns and sequence types (ST). While one patient was considered as having mcr-1-positive carbapenem-resistant E. coli (CREC) colonization, the other three mcr-1-positive CREC-related infections were classified as nosocomial infections. Only amikacin and tigecycline showed good in vitro activity against these four isolates, and three of them had a minimum inhibitory concentration with colistin of ≥4 mg/L. In the colistin-susceptible isolate, mcr-1 was nonfunctional due to the insertion of another gene. In addition, all of the mcr-1-positive CREC contained various resistant genes, such as AmpCCMY, blaNDM, blaTEM, blaSHV, and blaCTX. In addition, one strain (EC1037) had loss of the OMP. Conclusions: The emergence of the mcr-1 gene among CRE, especially E. coli, remains worth our attention due to its resistance to most antibiotics, and a further national survey is warranted.

Antimicrobial Activity of Lactobacillus Species Against Carbapenem-Resistant Enterobacteriaceae.

OBJECTIVE: This study aims to identify suitable lactobacilli that have anti-carbapenem-resistant Enterobacteriaceae (CRE) activity with in vitro tolerance to pepsin and bile salts. METHODS: Fifty-seven Lactobacillus spp. strains encompassing nine species were collected for investigation. Their viabilities in the presence of pepsin and bile salts were tested using tolerance tests. Their anti-CRE effects were assessed by agar well diffusion and broth microdilution assay, as well as time-kill test. RESULTS: Of the 57 Lactobacillus isolates collected, 31 had a less than 2-log reduction in their viability in both pepsin and bile salt tolerance tests. Of these 31 isolates, 5 (LUC0180, LUC0219, LYC0289, LYC0413, and LYC1031) displayed the greatest anti-CRE activity with a CRE zone of inhibition greater than 15 mm in agar well diffusion assays. The minimal inhibitory percentages of supernatants from these five strains against CREs ranged from 10 to 30%. With the exception of LUC0180, which had a minimal bactericidal percentage ≥ 40%, the bactericidal percentage of all the strains ranged from 20 to 40%. The inhibitory effect of the cell-free culture supernatants from these Lactobacillus strains did not change after heating but was abolished as the pH changed to 7.0. After a 24-h incubation, five of the Lactobacillus strains at a concentration of 108 CFU/ml totally inhibited the growth of carbapenem-resistant Escherichia coli (CRE316) and Klebsiella pneumoniae (CRE632). After a 48-h incubation, the growth of CRE316 was completely inhibited under each concentration of lactobacilli based on time-kill test. Furthermore, when the concentration of lactobacilli was at 108 CFU/ml, the decline in pH was faster than at other concentrations. CONCLUSION: Some Lactobacillus strains exhibit anti-CRE activity, which suggests potential applications for controlling or preventing CRE colonization or infection.

Colistin-sparing regimens against Klebsiella pneumoniae carbapenemase-producing K. pneumoniae isolates: Combination of tigecycline or doxycycline and gentamicin or amikacin.

BACKGROUND/PURPOSE: In vitro studies of the combination of an aminoglycoside with tigecycline or doxycycline against Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae isolates are rarely published. The goal of this study was to evaluate the antibacterial activity of the combination regimens. METHODS: Thirteen genetically different KPC-producing K. pneumoniae isolates were randomly selected. Drug concentrations of amikacin, gentamicin, tigecycline, and doxycycline were adjusted to 1-, 1/2-, and 1/4-fold of respective minimum inhibitory concentrations (MICs). Each drug alone or the combinations of amikacin or gentamicin with tigecycline or doxycycline were tested by combination studies. RESULTS: Treatment with the 1× MIC concentration in combinations of amikacin or gentamicin and tigecycline or doxycycline for 24 hours resulted in bactericidal activity of 84-100% in the isolates. Treatment with 1/2× MIC combinations resulted in synergism of 69-100% in the isolates. Notably, doxycycline plus gentamicin or amikacin was synergistic for all tested isolates. However, bactericidal or synergistic effect was barely evident following 1/4× MIC combinations. There was no antagonism in any of the combination regimens. CONCLUSION: Enhanced activity was noted following treatment with doxycycline combined with gentamicin or amikacin against KPC-producing K. pneumoniae isolates, warranting further in vitro and animal investigations before clinical application.

Recommendations and guidelines for the treatment of pneumonia in Taiwan.

Pneumonia is a leading cause of death worldwide, ranking third both globally and in Taiwan. This guideline was prepared by the 2017 Guidelines Recommendations for Evidence-based Antimicrobial agents use in Taiwan (GREAT) working group, formed under the auspices of the Infectious Diseases Society of Taiwan (IDST). A consensus meeting was held jointly by the IDST, Taiwan Society of Pulmonary and Critical Care Medicine (TSPCCM), the Medical Foundation in Memory of Dr. Deh-Lin Cheng, the Foundation of Professor Wei-Chuan Hsieh for Infectious Diseases Research and Education and CY Lee's Research Foundation for Pediatric Infectious Diseases and Vaccines. The final guideline was endorsed by the IDST and TSPCCM. The major differences between this guideline and the 2007 version include the following: the use of GRADE methodology for the evaluation of available evidence whenever applicable, the specific inclusion of healthcare-associated pneumonia as a category due to the unique medical system in Taiwan and inclusion of recommendations for treatment of pediatric pneumonia. This guideline includes the epidemiology and recommendations of antimicrobial treatment of community-acquired pneumonia, hospital-acquired pneumonia, ventilator-associated pneumonia, healthcare-associated pneumonia in adults and pediatric pneumonia.

In vitro and in vivo antibacterial activity of tigecycline against Vibrio vulnificus.

BACKGROUND/PURPOSE: The aim of this study is to investigate the role of tigecycline in Vibrio vulnificus infection. METHODS: Eight randomly selected clinical V. vulnificus isolates were studied to obtain the minimal inhibitory concentrations (MICs) of minocycline, cefotaxime, and tigecycline, and the time-kill curves of tigecycline alone or in combination with other drugs. A peritonitis mouse model was used for the evaluation of the therapeutic efficacy of tigecycline alone or cefotaxime in combination with minocycline or tigecycline. RESULTS: The MIC of minocycline, cefotaxime, and tigecycline for eight clinical V. vulnificus isolates was 0.06-0.12 µg/mL, 0.03-0.06 µg/mL, and 0.03-0.06 µg/mL, respectively. In time-killing studies, at the concentration of 1 × MIC, the inhibitory effect of tigecycline persisted for 24 hours in five of eight isolates. With 2 × MIC and trough level, the inhibitory effect was noted in all isolates for 24 hours. With the combination of minocycline plus cefotaxime and tigecycline plus cefotaxime at 1/2 × MIC, the bactericidal effect was noted in 25% and 62.5% of eight isolates and synergism in 50% and 75% of isolates. With a low (1.25 × 105 CFU/mL) inoculum, all infected mice survived with tigecycline alone, tigecycline plus cefotaxime, or minocycline plus cefotaxime on the 14th day. At the inoculum of 1.25 × 106 CFU, the survival rate was 33.3% on the 14th day in the tigecycline plus cefotaxime-treated group, but none of the mice treated by tigecycline alone or minocycline plus cefotaxime survived (33.3% vs. 0%, p = 0.01 by Fisher's exact test). CONCLUSION: Our in vitro combination and animal studies indicate that tigecycline could be an option for the treatment of invasive V. vulnificus infections.

Simultaneous three Enterobacteriaceae with different bla NDM-1-encoding plasmids in a patient transferred from mainland China to Taiwan.

New-Delhi metallo-ß-lactamase1 (NDM-1) Enterobacteriaceae are increasing worldwide. Herein, we describe a single patient who carried three unusual NDM-1 carbapenem-resistant Enterobacteriaceae - Enterobacter cloacae (E. cloacae) yielded from a urine specimen and Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. coli) from stool specimens. For E. cloacae, its bla NDM-1-encoding plasmid was pKP04NDM with a size of ~54 kb replicons with an IncN backbone. For K. pneumoniae, its bla NDM-1-encoding plasmid was pNDM-BTR with a size of ~59.6 kb and belonged to IncN. For E. coli, its main bla NDM-1-encoding plasmid was pIMP-HK1500, and the NDM-1 gene was obtained from a part of pNDM-BTR (8439 bp). These three clinical strains are reported for the first time and are assumed to be imported from mainland China to Taiwan. The three different plasmids were never reported in K. pneumoniae, E. coli, and Citrobacter spp before. Owing to their associated multidrug resistance, appropriate measures of periodic, targeted surveillance, and development of new antimicrobial agents are urgently needed.

Implementing a novel model for hospice and palliative care in the emergency department: An experience from a tertiary medical center in Taiwan.

Hospice and palliative care has been recognized as an essential part of emergency medicine; however, there is no consensus on the optimal model for the delivery of hospice and palliative care in the emergency department (ED). Therefore, we conducted a novel implementation in a tertiary medical center in Taiwan. In the preintervention period, we recruited a specialist for hospice and palliative medicine in the ED to lead our intervention. In the early stage of the intervention, starting on July 1, 2014, we encouraged and funded ED physicians and nurses to receive training for hospice and palliative medicine and residents of emergency medicine to rotate to the hospice ward. In the late stage of the intervention, we initiated educational programs in the ED, an interdisciplinary meeting with the hospice team every month, sharing information and experience via a cell phone communication app, and setting aside an emergency hospice room for end-of-life patients. We compared the outcomes among pre-, during, and postintervention periods. Compared with 4 in the preintervention period, the cases of do not resuscitate (DNR) per month increased significantly to 30.1 in the early stage of intervention, 23.9 in late stage of intervention, and 34.6 in the postintervention period (all P < .001 compared with the preintervention period). Compared with 10.8% in the preintervention period, the ratio of DNR orders signed in the ED/total DNR orders signed in the study hospital was increased to 17.1% in early stage of intervention, 12.5% in late stage of intervention, and 22.8% in postintervention. Compared with zero in preintervention and early intervention, the cases of consultation with the hospice team increased significantly to 19 cases per month in the late stage of intervention and postintervention. The ability of nurses in hospice and palliative care, including knowledge and the timing and method of consultation with the hospice team, was also significantly improved. We successfully implemented a novel model of hospice and palliative care in the ED via a champion, education, and close collaboration with the hospice team, which could be an important reference for other EDs and intensive care unit in the future.

Cephalosporin-Glycopeptide Combinations for Use against Clinical Methicillin-Resistant Staphylococcus aureus Isolates: Enhanced In vitro Antibacterial Activity.

The empirical combination of both a beta-lactam and glycopeptide to counter potential staphylococcal pathogens may improve the clinical outcomes for cases of Staphylococcus aureus bacteremia. We reported comparative in vitro studies of combination effects of different cephalosporins (i.e., cefazolin, cefmetazole, cefotaxime, and cefepime) combined with glycopeptides for 34 randomly selected methicillin-resistant S. aureus (MRSA) isolates by three methods, including the checkerboard, time-killing, and combination MIC measurement methods. Thirteen SCCmec type III isolates with a cefazolin MIC of ≥ 128 µg/mL were classified as the high-cefazolin MIC (HCM) group, whereas 13 SCCmec type IV and 8 SCCmec type V isolates were classified as the low-cefazolin MIC (LCM) group. With the checkerboard method, synergism was present for vancomycin-based combinations at 30.8-69.2 and 13.6-66.7%, as well as teicoplanin-based combinations of 38.5-84.6 and 0-47.6%, of the HCM and LCM isolates, respectively. No antagonism was noted. The in vitro inhibitory activity was evident even at a low concentration of 1/512x MIC of cephalosporin combined with sub-inhibitory concentrations (1/2x MIC) of a glycopeptide. With time-killing assays, synergism was noted at 1/2x or 1x susceptible breakpoint concentrations (SBCs) of a cephalosporin combined with 1/4 or 1/2 MIC of a glycopeptide. In the presence of 1/2 SBC of a cephalosporin, vancomycin or teicoplanin MICs decreased an average of 2.0- to 6.6- or 1.6- to 5.5-fold, respectively. With 8 µg/mL cephalosporin, the decline of glycopeptide MICs was most obvious in the presence of cefmetazole. In conclusion, cephalosporin-glycopeptide combinations at clinically achievable concentrations can exhibit in vitro synergistic antibacterial activity against clinical MRSA isolates. Such combinations require more clinical data to support their application for use in human MRSA infections.

RNA polymerase B subunit gene mutations in biofilm-embedded methicillin-resistant Staphylococcus aureus following rifampin treatment.

BACKGROUND/PURPOSE: This study was conducted to compare the mutation rates of different rpoB sites and rifampin minimum inhibitory concentration (MIC) changes prior to and after rifampin therapy for biofilm-embedded methicillin-resistant Staphylococcus aureus (MRSA) isolates. METHODS: The screening of rifampin-resistant MRSA isolates, from the biofilm at Day 5 with or without exposure to the susceptible breakpoint concentration of rifampin recommended by the Clinical and Laboratory Standards Institute (1 mg/L), was conducted using agar plates containing rifampin. A partial fragment of RNA polymerase B subunit gene (rpoB), including clusters I and II, was amplified and sequenced. The rifampin MIC values and mutation frequencies at different sites of rpoB were measured and evaluated in rifampicin-resistant isolates. RESULTS: Rifampin-resistant mutants could be selected from all of 39 randomly selected rifampin-susceptible MRSA isolates in the biofilm model. The spontaneous mutation frequency ranged from 1.00 × 10(-4) to 3.85 × 10(-7). Mutation at codon 481 was most commonly found at 35 (89.7%) of 39 MRSA isolates. Without rifampin induction, the MIC ranged between 0.125 mg/L and1024 mg/L and mutation sites included cluster I 464, 466, 468, 471, 474, 477, 481, 484, 486 and cluster II 519, 527, 529 with the percentage of 471 (35.9%), 477 (33.3%), 481 (53.8%), and 484 (35.9%). Conversely, with the induction of rifampin, the MIC value ranged ∼256-1024 mg/L. The mutation sites that were more concentrated included 468 (17.9%), 477 (30.8%), 481 (89.7%), 484 (17.9%), and 486 (33.3%). CONCLUSION: We documented high rifampin resistance induction activity when MRSA was engaged in biofilm with rifampin exposure. Monotherapy seems to be inadequate for MRSA in biofilm. There is an urgent need for developing effective combination therapies with less rifampin resistance-inducing activities for treating MRSA in biofilms.

In vitro efficacy of fosfomycin-based combinations against clinical vancomycin-resistant Enterococcus isolates.

Vancomycin-resistant (VR) enterococci (VRE) are increasingly important nosocomial pathogens, commonly causing catheter-related urinary tract infections or vascular catheter-related bloodstream infections. In this study, 10 Enterococcus faecium and 9 Enterococcus faecalis different pulsed-field gel electrophoresis genome-type VR clinical isolates were detected. The potential role of fosfomycin-based combination regimens for biofilm-related VRE infection is in vitro evaluated. Anti-VRE activities of fosfomycin, ampicillin, linezolid, minocycline, rifampicin, tigecycline, teicoplanin, vancomycin alone, or fosfomycin-based combinations were studied by time-kill method and a biofilm model. Of the fosfomycin-based combinations, a synergistic effect was particularly noted for teicoplanin against 89% of the VR E. faecalis isolates. In a biofilm model, only linezolid alone was able to reduce the bacterial loads, and the use of fosfomycin-based combinations, excluding rifampicin (40%), failed to enhance antibacterial activity against VR E. faecium. For E. faecalis, an inhibitory effect was evident using ampicillin alone or fosfomycin plus rifampicin (100%), tigecycline (56%), or teicoplanin (44%). However, an antagonistic effect was found for ampicillin plus fosfomycin against 2 of 3 of the VR E. faecalis isolates. The antibacterial activities of the drugs tested against VRE in vitro varied by species. Ampicillin exhibited potential activity against planktonic- and biofilm-embedded VR E. faecalis. Fosfomycin-based combinations may have enhanced antibacterial effects against VRE even in the biofilm model, and this observation warrants further clinical studies.