Excellence in Antibiotic Stewardship: A mixed methods study comparing High, Medium, and Low Performing Hospitals.

BACKGROUND: Despite antibiotic stewardship programs existing in most acute care hospitals, there continues to be variation in appropriate antibiotic use. While existing research examines individual prescriber behavior, contextual reasons for variation are poorly understood. METHODS: We conducted an explanatory, sequential mixed methods study of a purposeful sample of 7 hospitals with varying discharge antibiotic overuse. For each hospital, we conducted surveys, document analysis, and semi-structured interviews with antibiotic stewardship and clinical stakeholders. Data were analyzed separately and mixed during the interpretation phase, where each hospital was examined as a case, with findings organized across cases using a strengths, weaknesses, opportunities, and threats framework to identify factors accounting for differences in antibiotic overuse across hospitals. RESULTS: Surveys included 85 respondents. Interviews included 90 respondents (31 hospitalists, 33 clinical pharmacists, 14 stewardship leaders, 12 hospital leaders). On surveys, clinical pharmacists at hospitals with lower antibiotic overuse were more likely to report feeling: respected by hospitalist colleagues (p=0.001), considered valuable team members (p=0.001), comfortable recommending antibiotic changes (p=0.02). Based on mixed-methods analysis, hospitals with low antibiotic overuse had four distinguishing characteristics: a) robust knowledge of and access to antibiotic stewardship guidance, b) high quality clinical pharmacist-physician relationships, c) tools and infrastructure to support stewardship, and d) highly engaged Infectious Diseases physicians who advocated stewardship principles. CONCLUSION: This mixed-method study demonstrates the importance of organizational context for high performance in stewardship and suggests improving antimicrobial stewardship requires attention to knowledge, interactions, and relationships between clinical teams and infrastructure that supports stewardship and team interactions.

Azithromycin Versus Beta-lactams in Hospitalized Patients with Acute Exacerbations of COPD.

BACKGROUND: There is a lack of data comparing azithromycin to alternative antibiotic choices in managing COPD exacerbations, making appropriate antibiotic selection controversial. OBJECTIVE: To compare treatment failure in hospitalized patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) receiving azithromycin or beta-lactams. DESIGN: Retrospective, multicenter cohort study using logistic regression for multivariable analysis. Patients were included if they were at least 18 years old, admitted with AECOPD, and received at least two consecutive days of either a beta-lactam or azithromycin. Patients were excluded if they received concomitant azithromycin and beta-lactam antibiotics during the first 2 days, had a history of other severe underlying pulmonary diseases, pregnancy, COVID-19, alpha-1 antitrypsin deficiency, or received a corticosteroid for a diagnosis other than COPD. PARTICIPANTS: Five hundred ninety-five patients were included, of which 428 (72%) received azithromycin and 167 patients (28%) received a beta-lactam. MAIN MEASURES: The primary endpoint was treatment failure rate in patients receiving azithromycin versus beta-lactams, which was a composite endpoint defined as in-hospital mortality, admission to intensive care, initiation of invasive mechanical ventilation, initiation of a new antibiotic, steroid therapy escalation, or readmission due to AECOPD within 30 days. KEY RESULTS: The composite primary outcome occurred in 84 patients (19.6%) in the azithromycin group and 54 (32.3%) in the beta-lactam group (p<0.01). The difference in the composite outcome was a result of higher rates of new antibiotics during admission (12.6% vs 4.2%; p<0.01) and higher readmission within 30 days (19.3% vs 12.4%; p=0.032). After controlling for potential confounders, beta-lactams continued to demonstrate a higher risk for treatment failure (OR, 2.30; 95% CI, 1.46-3.63). There was no difference in adverse effects between the groups. CONCLUSION: Azithromycin was associated with less treatment failure in AECOPD which was driven by lower readmission rates and prescription of new antimicrobials.

Lysophosphatidic acid type 2 receptor agonists in targeted drug development offer broad therapeutic potential.

The growth factor-like lipid mediator, lysophosphatidic acid (LPA), is a potent signaling molecule that influences numerous physiologic and pathologic processes. Manipulation of LPA signaling is of growing pharmacotherapeutic interest, especially because LPA resembles compounds with drug-like features. The action of LPA is mediated through activation of multiple types of molecular targets, including six G protein-coupled receptors that are clear targets for drug development. However, the LPA signaling has been linked to pathological responses that include promotion of fibrosis, atherogenesis, tumorigenesis, and metastasis. Thus, a question arises: Can we harness, in an LPA-like drug, the many beneficial activities of this lipid without eliciting its dreadful actions? We developed octadecyl thiophosphate (OTP; subsequently licensed as Rx100), an LPA mimic with higher stability in vivo than LPA. This article highlights progress made toward developing analogs like OTP and exploring prosurvival and regenerative LPA signaling. We determined that LPA prevents cell death triggered by various cellular stresses, including genotoxic stressors, and rescues cells condemned to apoptosis. LPA2 agonists provide a new treatment option for secretory diarrhea and reduce gastric erosion caused by nonsteroidal anti-inflammatory drugs. The potential uses of LPA2 agonists like OTP and sulfamoyl benzoic acid-based radioprotectins must be further explored for therapeutic uses.

The association of psychiatric medication use with adherence in patients with HIV.

Over two million new cases of HIV infection will occur annually, worldwide. Triple drug anti-retroviral therapy (ART) decreases the viral load in patients with HIV, helping to stop progression of HIV infection to AIDs. Our study assessed how pharmacologic treatment for mental health issues affects medication adherence and viral load in patients with HIV. We conducted a retrospective chart review of 163 patients with HIV who had at least 2 visits at the HIV-clinic at Ascension St. John Hospital. Data were collected on demographics, medications, CD4 counts and viral loads. Data were analyzed using Student's t-test, the χ2 test, the Mann-Whitney U test and logistic regression. "Poor Compliance" was defined as at least 2 consecutive visits with a CD4 count <200 µL and/or with viral load ≥100 IU/ml. Patients taking antidepressants were less likely to have poor compliance than those not on anti-depressants (6.3% vs. 22.3%, p = 0.04). A similar association was found for patients taking any psychiatric drug (7.0% vs. 23.5%, p = 0.02). On multivariable analysis, the odds of poor compliance were 6.3 times higher in patients who stopped HIV therapy for greater than one week between visits (p = 0.004) and 3.6 times lower in patients taking any psychiatric medication (p = 0.05).

Use of Ceftaroline Fosamil in Osteomyelitis: CAPTURE Study Experience.

BACKGROUND: Osteomyelitis is often challenging to treat. This analysis examined the clinical experience of patients with gram-positive osteomyelitis treated with ceftaroline fosamil in the phase 4 Clinical Assessment Program and Teflaro® Utilization Registry (CAPTURE) study. METHODS: Data including patient demographics, past illnesses, risk factors, disease characteristics, antibiotic use, pathogens isolated, and clinical outcome were collected between September 2013 and February 2015 by review of randomly ordered patient charts from participating sites in the United States. Clinical success was defined as discontinuation of ceftaroline fosamil following clinical cure with no further need for antibiotics or clinical improvement with switch to another antibiotic treatment. RESULTS: A total of 150 patients with gram-positive osteomyelitis were treated with ceftaroline fosamil. Most patients (117/150; 78.0%) were treated with 600 mg ceftaroline fosamil per dose; 143/150 patients (95.3%) received a dose every 12 h. The majority (89/150 patients; 59.3%) had been previously diagnosed with diabetes mellitus or peripheral arterial disease. Osteomyelitis was associated with hardware in 32/150 patients (21.3%). Methicillin-resistant and methicillin-susceptible Staphylococcus aureus (MRSA; MSSA) were the most commonly isolated pathogens, observed in 93/150 (62.0%) and 21/150 (14.0%) patients, respectively. Clinical success with ceftaroline fosamil therapy was observed in 139/150 (92.7%) patients overall, 81/89 (91.0%) patients with diabetes or peripheral arterial disease, and 18/20 (90.0%) patients who had hardware implanted before ceftaroline fosamil therapy (none had hardware removed during therapy). Patients who received prior antibiotic therapy or ceftaroline fosamil as monotherapy experienced clinical success rates of 93.9% (107/114) and 91% (91/100), respectively. Among patients who received concurrent antibiotic therapy, the clinical success rate was 96.0% (48/50). Patients who were infected with MRSA or MSSA had clinical success rates of 92.5% (86/93) and 100% (21/21), respectively. A total of 2/150 (1.3%) patients discontinued ceftaroline fosamil therapy because of adverse events. CONCLUSIONS: Clinical success rates with ceftaroline fosamil were high in patients with gram-positive osteomyelitis, including those with diabetes or peripheral arterial disease and those with MRSA or MSSA.

Current trends in candidemia and species distribution among adults: Candida glabrata surpasses C. albicans in diabetic patients and abdominal sources.

Candidemia rate and species distribution vary according to the type of patients, country of origin and antifungal prophylaxis use. To present current candidemia epidemiological trends. A retrospective examination of candidemia in adults (≥18 years-old) hospitalised from 2007 to 2015. Cases were identified through the microbiology laboratory. Candida species were distinguished based on colony morphology and VITEK-2 YBC cards, (bioMerieux, Durham, NC, USA). Patient characteristics, species distribution, source and outcome were assessed. We encountered 275 patients (294 episodes) with candidemia. The rate of candidemia dropped in 2010 (P = 0.003) without further decline. Nearly all cases (97.5%) were healthcare-associated. C. albicans (n = 118) and C. glabrata (n = 77) proportions varied without a discernable trend. C. glabrata was more common in diabetics [52.9% vs. 32.0% (non-diabetics); P = 0.004] and abdominal sources [53.3% vs. 35.5% (other sources); P = 0.03], especially gastric/duodenal foci [88.9% vs. 44.1% (other abdominal foci); P = 0.02]. All-cause 30-day mortality rate was 43.3% without changes over time or differences between C. albicans and C. glabrata. In conclusion, the candidemia rate remains stable after a decline in 2010. C. albicans remains the most common species but C. glabrata predominates in diabetics and abdominal sources. These findings suggest possible species-related differences in colonisation dynamics or pathogenicity.

Meta-Analysis: Vancomycin Treatment Failures for MRSA Bacteremia Based on MIC Determined by E-test.

Background: Vancomycin is used to treat serious infections caused by methicillin-resistant Staphylococcus aureus (MRSA). It is unclear whether MRSA isolates with minimum inhibitory concentration (MIC) 1.5 to 2 µg/mL are successfully treated with vancomycin. Objective: Evaluate vancomycin failure rates in MRSA bacteremia with an MIC <1.5 versus ≥1.5 µg/mL, and MIC ≤1 versus ≥2 µg/mL. Methods: A literature search was conducted using MESH terms vancomycin, MRSA, bacteremia, MIC, treatment and vancomycin failure to identify human studies published in English. All studies of patients with MRSA bacteremia treated with vancomycin were included if they evaluated vancomycin failures, defined as mortality, and reported associated MICs determined by E-test. Study sample size, vancomycin failure rates, and corresponding MIC values were extracted and analyzed using RevMan 5.2.5. Results: Thirteen studies including 2955 patients met all criteria. Twelve studies including 2861 patients evaluated outcomes using an MIC cutoff of 1.5 µg/mL. A total of 413 of 1186 (34.8%) patients with an MIC <1.5 and 531 of 1675 (31.7%) patients with an MIC of ≥1.5 µg/mL experienced treatment failure (odds ratio = 0.72, 95% confidence interval = 0.49-1.04, P = .08). Six studies evaluated 728 patients using the cutoffs of ≤1 and ≥2 µg/mL. A total of 384 patients had isolates with MIC ≤1 µg/mL, 344 had an MIC ≥2 µg/mL. Therapeutic failure occurred in 87 and 102 patients, respectively (odds ratio = 0.61, 95% confidence interval = 0.34-1.10, P = .10). As heterogeneity between the studies was high, a random-effects model was used. Conclusion: Vancomycin MIC may not be an optimal sole indicator of vancomycin treatment failure in MRSA bacteremia.

Predictors of immune reconstitution syndrome in organ transplant recipients with cryptococcosis: implications for the management of immunosuppression.

BACKGROUND: Risk factors including how changes in immunosuppression influence the occurrence of immune reconstitution syndrome (IRS) in solid organ transplant (SOT) recipients with cryptococcosis have not been fully defined. METHODS: SOT recipients with cryptococcosis were identified and followed for 12 months. IRS was defined based on previously proposed criteria. RESULTS: Of 89 SOT recipients, 13 (14%) developed IRS. Central nervous system (CNS) disease (adjusted odds ratio [AOR], 6.23; P = .03) and discontinuation of calcineurin inhibitor (AOR, 5.11; P = .02) were independently associated with IRS. Only 2.6% (1/13) of the patients without these risk factors developed IRS compared with 18.8% (6/32) with 1 risk factor, and 50% (6/12) with both risk factors (χ(2) for trend, P = .0001). Among patients with CNS disease, those with neuroimaging abnormalities (P = .03) were more likely to develop IRS, irrespective of serum or CSF cryptococcal antigen titers and fungemia. Graft rejection after cryptococcosis was observed in 15.4% (2/13) of the patients with IRS compared with 2.6% (2/76) of those without IRS (P = .07). CONCLUSIONS: We determined variables that pose a risk for IRS and have shown that discontinuation of calcineurin inhibitors was independently associated with 5-fold increased risk of IRS in transplant recipients with cryptococcosis.

The quad pill, a once-daily combination therapy for HIV infection.

The quad pill is the newest single-pill, once-daily option for the treatment of human immunodeficiency virus (HIV) type 1 infection. In addition to tenofovir difumarate (TDF) and emtricitabine (FTC), the quad pill includes cobicistat (COBI; an inactivator of cytochrome P450 isoenzyme CYP3A without anti-HIV activity) and a new integrase inhibitor, elvitegravir (EVG). The quad does not have drug interactions with H2-receptor antagonists or proton pump inhibitors, does not cause central nervous system (CNS) side effects, and is pregnancy category B. It does have substantial drug interactions with medications that are metabolized using CYP3A and causes reversible declines in estimated glomerular filtration rate (eGFR) owing to inhibition of renal tubule transport of creatinine. In clinical trials, the virologic and immunologic efficacy of the quad pill is equivalent to that of other comparator regimens with low rates of discontinuation. The major side effect is nauseam which is self-limited, and the primary mutations associated with treatment failure frequently lead to cross-resistance with raltegravir (RAL).

Infectious diseases subspecialty: declining demand challenges and opportunities.

Recent match results from the National Resident Matching Program for the subspecialty of infectious diseases show an ongoing decline in the number of fellowship positions filled, and, more important, in the number of applicants, particularly from the pool of international medical graduates. The main reasons for this declining application rate are unclear; in the absence of hard data, we present our viewpoint on this issue. Difficulties in securing visas for permanent residency in the United States, perception of a limited job market, and the explosive growth in the number of hospitalist positions may be important contributing factors. Infectious Diseases Society of America members need to focus on medical students and medical residents in their formative years. We present potential solutions to this problem of declining interest in the field of infectious diseases.

Cyclin-dependent kinases regulate apoptosis of intestinal epithelial cells.

Homeostasis of the gastrointestinal epithelium is dependent upon a balance between cell proliferation and apoptosis. Cyclin-dependent kinases (Cdks) are well known for their role in cell proliferation. Previous studies from our group have shown that polyamine-depletion of intestinal epithelial cells (IEC-6) decreases cyclin-dependent kinase 2 (Cdk2) activity, increases p53 and p21Cip1 protein levels, induces G1 arrest, and protects cells from camptothecin (CPT)-induced apoptosis. Although emerging evidence suggests that members of the Cdk family are involved in the regulation of apoptosis, their roles directing apoptosis of IEC-6 cells are not known. In this study, we report that inhibition of Cdk1, 2, and 9 (with the broad range Cdk inhibitor, AZD5438) in proliferating IEC-6 cells triggered DNA damage, activated p53 signaling, inhibited proliferation, and induced apoptosis. By contrast, inhibition of Cdk2 (with NU6140) increased p53 protein and activity, inhibited proliferation, but had no effect on apoptosis. Notably, AZD5438 sensitized, whereas, NU6140 rescued proliferating IEC-6 cells from CPT-induced apoptosis. However, in colon carcinoma (Caco-2) cells with mutant p53, treatment with either AZD5438 or NU6140 blocked proliferation, albeit more robustly with AZD5438. Both Cdk inhibitors induced apoptosis in Caco-2 cells in a p53-independent manner. In serum starved quiescent IEC-6 cells, both AZD5438 and NU6140 decreased TNF-α/CPT-induced activation of p53 and, consequently, rescued cells from apoptosis, indicating that sustained Cdk activity is required for apoptosis of quiescent cells. Furthermore, AZD5438 partially reversed the protective effect of polyamine depletion whereas NU6140 had no effect. Together, these results demonstrate that Cdks possess opposing roles in the control of apoptosis in quiescent and proliferating cells. In addition, Cdk inhibitors uncouple proliferation from apoptosis in a p53-dependent manner.

The mechanism by which MEK/ERK regulates JNK and p38 activity in polyamine depleted IEC-6 cells during apoptosis.

Polyamine-depletion inhibited apoptosis by activating ERK1/2, while, preventing JNK1/2 activation. MKP-1 knockdown by SiRNA increased ERK1/2, JNK1/2, and p38 phosphorylation and apoptosis. Therefore, we predicted that polyamines might regulate MKP1 via MEK/ERK and thereby apoptosis. We examined the role of MEK/ERK in the regulation of MKP1 and JNK, and p38 activities and apoptosis. Inhibition of MKP-1 activity with a pharmacological inhibitor, sanguinarine (SA), increased JNK1/2, p38, and ERK1/2 activities without causing apoptosis. However, pre-activation of these kinases by SA significantly increased camptothecin (CPT)-induced apoptosis suggesting different roles for MAPKs during survival and apoptosis. Inhibition of MEK1 activity prevented the expression of MKP-1 protein and augmented CPT-induced apoptosis, which correlated with increased activities of JNK1/2, caspases, and DNA fragmentation. Polyamine depleted cells had higher levels of MKP-1 protein and decreased JNK1/2 activity and apoptosis. Inhibition of MEK1 prevented MKP-1 expression and increased JNK1/2 and apoptosis. Phospho-JNK1/2, phospho-ERK2, MKP-1, and the catalytic subunit of PP2Ac formed a complex in response to TNF/CPT. Inactivation of PP2Ac had no effect on the association of MKP-1 and JNK1. However, inhibition of MKP-1 activity decreased the formation of the MKP-1, PP2Ac and JNK complex. Following inhibition by SA, MKP-1 localized in the cytoplasm, while basal and CPT-induced MKP-1 remained in the nuclear fraction. These results suggest that nuclear MKP-1 translocates to the cytoplasm, binds phosphorylated JNK and p38 resulting in dephosphorylation and decreased activity. Thus, MEK/ERK activity controls the levels of MKP-1 and, thereby, regulates JNK activity in polyamine-depleted cells.

Ceftaroline-heteroresistant Staphylococcus aureus.

Heteroresistance refers to the presence, within a large population of antimicrobial-susceptible microorganisms, of subpopulations with lesser susceptibilities. Ceftaroline is a novel cephalosporin with activity against methicillin-resistant Staphylococcus aureus (MRSA). The aim of this study was to detect the prevalence of ceftaroline heteroresistance in vitro in a select group of S. aureus strains. There were 57 isolates selected for evaluation, 20 MRSA, 20 vancomycin-intermediate S. aureus (VISA), 7 daptomycin-nonsusceptible S. aureus (DNSSA), 6 linezolid-nonsusceptible S. aureus (LNSSA), and 4 heteroresistant VISA (hVISA) isolates. MICs and minimal bactericidal concentrations were determined using the broth microdilution method according to CLSI guidelines. All of the isolates were analyzed by pulsed-field gel electrophoresis. The staphylococcal cassette chromosome mec element (SCCmec) types were determined by a multiplex PCR. Population analysis profiles (PAPs) were performed to determine heteroresistance for all of the isolates using plates made by adding various amounts of ceftaroline to brain heart infusion agar. The frequencies of resistant subpopulations were 1 in 10(4) to 10(5) organisms. We determined that 12 of the 57 (21%) isolates tested were ceftaroline-heteroresistant S. aureus (CHSA). CHSA occurred among strains with reduced susceptibilities to vancomycin, daptomycin, and linezolid but occurred in none of the USA-300 isolates tested. Evaluation of the heteroresistant strains demonstrated that the phenotype was unstable. Further studies are needed to determine whether CHSA has a role in clinical failures and to determine the implications of our study findings.

Regulation of intestinal mucosal growth by amino acids.

Amino acids, especially glutamine (GLN) have been known for many years to stimulate the growth of small intestinal mucosa. Polyamines are also required for optimal mucosal growth, and the inhibition of ornithine decarboxylase (ODC), the first rate-limiting enzyme in polyamine synthesis, blocks growth. Certain amino acids, primarily asparagine (ASN) and GLN stimulate ODC activity in a solution of physiological salts. More importantly, their presence is also required before growth factors and hormones such as epidermal growth factor and insulin are able to increase ODC activity. ODC activity is inhibited by antizyme-1 (AZ) whose synthesis is stimulated by polyamines, thus, providing a negative feedback regulation of the enzyme. In the absence of amino acids mammalian target of rapamycin complex 1 (mTORC1) is inhibited, whereas, mTORC2 is stimulated leading to the inhibition of global protein synthesis but increasing the synthesis of AZ via a cap-independent mechanism. These data, therefore, explain why ASN or GLN is essential for the activation of ODC. Interestingly, in a number of papers, AZ has been shown to inhibit cell proliferation, stimulate apoptosis, or increase autophagy. Each of these activities results in decreased cellular growth. AZ binds to and accelerates the degradation of ODC and other proteins shown to regulate proliferation and cell death, such as Aurora-A, Cyclin D1, and Smad1. The correlation between the stimulation of ODC activity and the absence of AZ as influenced by amino acids is high. Not only do amino acids such as ASN and GLN stimulate ODC while inhibiting AZ synthesis, but also amino acids such as lysine, valine, and ornithine, which inhibit ODC activity, increase the synthesis of AZ. The question remaining to be answered is whether AZ inhibits growth directly or whether it acts by decreasing the availability of polyamines to the dividing cells. In either case, evidence strongly suggests that the regulation of AZ synthesis is the mechanism through which amino acids influence the growth of intestinal mucosa. This brief article reviews the experiments leading to the information presented above. We also present evidence from the literature that AZ acts directly to inhibit cell proliferation and increase the rate of apoptosis. Finally, we discuss future experiments that will determine the role of AZ in the regulation of intestinal mucosal growth by amino acids.

Spermidine, a sensor for antizyme 1 expression regulates intracellular polyamine homeostasis.

Although intracellular polyamine levels are highly regulated, it is unclear whether intracellular putrescine (PUT), spermidine (SPD), or spermine (SPM) levels act as a sensor to regulate their synthesis or uptake. Polyamines have been shown to induce AZ1 expression through a unique +1 frameshifting mechanism. However, under physiological conditions which particular polyamine induces AZ1, and thereby ODC activity, is unknown due to their inter-conversion. In this study we demonstrate that SPD regulates AZ1 expression under physiological conditions in IEC-6 cells. PUT and SPD showed potent induction of AZ1 within 4 h in serum-starved confluent cells grown in DMEM (control) medium. Unlike control cells, PUT failed to induce AZ1 in cells grown in DFMO containing medium; however, SPD caused a robust AZ1 induction in these cells. SPM showed very little effect on AZ1 expression in both the control and polyamine-depleted cells. Only SPD induced AZ1 when S-adenosylmethionine decarboxylase (SAMDC) and/or ODC were inhibited. Surprisingly, addition of DENSpm along with DFMO restored AZ1 induction by putrescine in polyamine-depleted cells suggesting that the increased SSAT activity in response to DENSpm converted SPM to SPD, leading to the expression of AZ1. This study shows that intracellular SPD levels controls AZ1 synthesis.

Antizyme (AZ) regulates intestinal cell growth independent of polyamines.

Since antizyme (AZ) is known to inhibit cell proliferation and to increase apoptosis, the question arises as to whether these effects occur independently of polyamines. Intestinal epithelial cells (IEC-6) were grown in control medium and medium containing 5 mM difluoromethylornithine (DFMO) to inhibit ODC, DFMO + 5 µM spermidine (SPD), DFMO + 5 µM spermine (SPM), or DFMO + 10 µM putrescine (PUT) for 4 days and various parameters of growth were measured along with AZ levels. Cell counts were significantly decreased and mean doubling times were significantly increased by DFMO. Putrescine restored growth in the presence of DFMO. However, both SPD and SPM when added with DFMO caused a much greater inhibition of growth than did DFMO alone, and both of these polyamines caused a dramatic increase in AZ. The addition of SPD or SPM to media containing DFMO + PUT significantly inhibited growth and caused a significant increase in AZ. IEC-6 cells transfected with AZ-siRNA grew more than twice as rapidly as either control cells or those incubated with DFMO, indicating that removal of AZ increases growth in cells in which polyamine synthesis is inhibited as well as in control cells. In a separate experiment, the addition of SPD increased AZ levels and inhibited growth of cells incubated with DFMO by 50%. The addition of 10 mM asparagine (ASN) prevented the increase in AZ and restored growth to control levels. These results show that cell growth in the presence or absence of ODC activity and in the presence or absence of polyamines depends only on the levels of AZ. Therefore, the effects of AZ on cell growth are independent of polyamines.

Recurrent streptococcal toxic shock syndrome due to distinct episodes of Streptococcus dysgalactiae and Streptococcus agalactiae septic arthritis.

Streptococcal toxic shock syndrome (STSS) is an uncommon disorder characterised by hypotension and multiorgan failure in the setting of streptococcal infection. Recurrent STSS is rare and has been due to recurrence of the same streptococcal species. Here, we present a case of a patient who developed recurrent STSS from a Streptococcus dysgalactiae right native joint septic arthritis and subsequently from a Streptococcus agalactiae left native joint septic arthritis.

Predictors of prolonged length of stay in adult patients with respiratory syncytial virus infections - a multi-center historical cohort study.

Objectives: Several studies have reported risk factors for severe disease and mortality in hospitalized adults with RSV infections. There is limited information available regarding the factors that affect the duration of a patient's hospital length of stay (LOS). Methods: This was a multicenter historical cohort study of adult patients hospitalized for laboratory-confirmed RSV in Southeast Michigan between January 2017 and December 2021. Hospitalized patients were identified using the International Classification of Diseases, Tenth Revision 10 codes for RSV infection. Mean LOS was computed; prolonged LOS was defined as greater than the mean. Results: We included 360 patients with a mean age (SD) of 69.9 ± 14.7 years, 63.6% (229) were female and 63.3% (228) of white race. The mean hospital LOS was 7.1 ± 5.4 days. Factors associated with prolonged LOS in univariable analysis were old age, body mass index (BMI), smoking status, Charlson Weighted Index of Comorbidity (CWIC), home oxygen, abnormal chest x-ray (CXR), presence of sepsis, use of oxygen, and antibiotics at the time of presentation. Predictors for prolonged LOS on admission in multivariable analysis were age on admission (p < 0.001), smoking status (p = 0.001), CWIC (p = 0.038) and abnormal CXR (p = 0.043). Interpretation: Our study found that age on admission, smoking history, higher CWIC and abnormal CXR on admission were significantly associated with prolonged LOS among adult patients hospitalized with RSV infection. These findings highlight the significance of promptly recognizing and implementing early interventions to mitigate the duration of hospitalization for adult patients suffering from RSV infection.

Amino acids regulate expression of antizyme-1 to modulate ornithine decarboxylase activity.

In a glucose-salt solution (Earle's balanced salt solution), asparagine (Asn) stimulates ornithine decarboxylase (ODC) activity in a dose-dependent manner, and the addition of epidermal growth factor (EGF) potentiates the effect of Asn. However, EGF alone fails to activate ODC. Thus, the mechanism by which Asn activates ODC is important for understanding the regulation of ODC activity. Asn reduced antizyme-1 (AZ1) mRNA and protein. Among the amino acids tested, Asn and glutamine (Gln) effectively inhibited AZ1 expression, suggesting a differential role for amino acids in the regulation of ODC activity. Asn decreased the putrescine-induced AZ1 translation. The absence of amino acids increased the binding of eukaryotic initiation factor 4E-binding protein (4EBP1) to 5'-mRNA cap and thereby inhibited global protein synthesis. Asn failed to prevent the binding of 4EBP1 to mRNA, and the bound 4EBP1 was unphosphorylated, suggesting the involvement of the mammalian target of rapamycin (mTOR) in the regulation of AZ1 synthesis. Rapamycin treatment (4 h) failed to alter the expression of AZ1. However, extending the treatment (24 h) allowed expression in the presence of amino acids, indicating that AZ1 is expressed when TORC1 signaling is decreased. This suggests the involvement of cap-independent translation. However, transient inhibition of mTORC2 by PP242 completely abolished the phosphorylation of 4EBP1 and decreased basal as well as putrescine-induced AZ1 expression. Asn decreased the phosphorylation of mTOR-Ser(2448) and AKT-Ser(473), suggesting the inhibition of mTORC2. In the absence of amino acids, mTORC1 is inhibited, whereas mTORC2 is activated, leading to the inhibition of global protein synthesis and increased AZ1 synthesis via a cap-independent mechanism.

In Vitro Activity of Retapamulin against Staphylococcus aureus Resistant to Various Antimicrobial Agents.

Retapamulin and six other antimicrobial agents were evaluated against 155 methicillin-resistant Staphylococcus aureus (MRSA) isolates, including strains resistant to vancomycin, linezolid, daptomycin, and mupirocin by microdilution tests. Time-kill assays were performed against representative MRSA, vancomycin-intermediate S. aureus (VISA), and vancomycin-resistant S. aureus (VRSA) isolates. Retapamulin and mupirocin demonstrated MIC90s of 0.12 µg/ml and 8 µg/ml, respectively, with resistance seen in 2.6% and 10% of isolates, respectively. Retapamulin maintained good activity against 94% (15/16) of mupirocin-resistant isolates.