Standardization of an antiviral pipeline for human norovirus in human intestinal enteroids demonstrates nitazoxanide has no to weak antiviral activity

Human noroviruses (HuNoVs) are the leading cause of acute gastroenteritis. In immunocompetent hosts, symptoms usually resolve within 3 days; however, in immunocompromised persons, HuNoV infection can become persistent, debilitating, and sometimes life-threatening. There are no licensed therapeutics for HuNoV due to a near half-century delay in its cultivation. Treatment for chronic HuNoV infection in immunosuppressed patients anecdotally includes nitazoxanide, a broad-spectrum antimicrobial licensed for treatment of parasite-induced gastroenteritis. Despite its off-label use for chronic HuNoV infection, nitazoxanide has not been clearly demonstrated to be an effective treatment. In this study, we standardized a pipeline for antiviral testing using multiple human small intestinal enteroid lines representing different intestinal segments and evaluated whether nitazoxanide inhibits replication of five HuNoV strains in vitro. Nitazoxanide did not exhibit high selective antiviral activity against any HuNoV strain tested, indicating it is not an effective antiviral for HuNoV infection. Human intestinal enteroids are further demonstrated as a model to serve as a preclinical platform to test antivirals against HuNoVs to treat gastrointestinal disease. Abstr.

A Standardized Antiviral Pipeline for Human Norovirus in Human Intestinal Enteroids Demonstrates No Antiviral Activity of Nitazoxanide

Human noroviruses (HuNoVs) are the leading cause of acute gastroenteritis. In immunocompetent hosts, symptoms usually resolve within three days; however, in immunocompromised persons, HuNoV infection can become persistent, debilitating, and sometimes life-threatening. There are no licensed therapeutics for HuNoV due to a near half-century delay in its cultivation. Treatment for chronic HuNoV infection in immunosuppressed patients anecdotally includes nitazoxanide, a broad-spectrum antimicrobial licensed for treatment of parasite-induced gastroenteritis. Despite its off-label use for chronic HuNoV infection, nitazoxanide has not been clearly demonstrated to be an effective treatment. In this study, we established a standardized pipeline for antiviral testing using multiple human small intestinal enteroid (HIE) lines representing different intestinal segments and evaluated whether nitazoxanide inhibits replication of 5 HuNoV strains in vitro . Nitazoxanide did not exhibit high selective antiviral activity against any HuNoV strains tested, indicating it is not an effective antiviral for norovirus infection. HIEs are further demonstrated as a model to serve as a pre-clinical platform to test antivirals against human noroviruses to treat gastrointestinal disease.

Adjunctive Rifampin Following Debridement and Implant Retention for Staphylococcal Prosthetic Joint Infection: Is it Effective if not Combined With a Fluoroquinolone?

Whether rifampin benefits retained staphylococcal prosthetic joint infection is unsettled. In a meta-analysis of 8 studies, we found greater clinical cure with fluoroquinolone-rifampin vs all other regimens (odds ratio [OR], 2.68; 95% CI, 1.43-5.02), but no greater cure with other rifampin combinations vs regimens without rifampin (OR, 1.22; 95% CI, 0.79-1.88).

Deconstructing the Dogma: Systematic Literature Review and Meta-analysis of Adjunctive Gentamicin and Rifampin in Staphylococcal Prosthetic Valve Endocarditis

BACKGROUND

Based primarily on in vitro and animal models, with little data directly addressing patient outcomes, current guidelines recommend treating staphylococcal prosthetic valve endocarditis (PVE) with antibiotic combinations including gentamicin and rifampin. Here, we synthesize the clinical data on adjunctive rifampin and gentamicin in staphylococcal PVE.

METHODS

We conducted a systematic review and meta-analysis of PubMed- and Cochrane-indexed studies reporting outcomes of staphylococcal PVE treated with adjunctive rifampin, gentamicin, both agents, or neither (ie, glycopeptide or β-lactam monotherapy). We recorded outcomes including mortality, relapsed infection, length of stay, nephrotoxicity, hepatotoxicity, and important drug-drug interactions (DDIs).

RESULTS

Four relevant studies were identified. Two studies (n = 117) suggested that adding gentamicin to rifampin-containing regimens did not reduce clinical failure (odds ratio [OR], 0.98 [95% confidence interval {CI}, .39-2.46]), and 2 studies (n = 201) suggested that adding rifampin to gentamicin-containing regimens did not reduce clinical failure (OR, 1.29 [95% CI, .71-2.33]). Neither gentamicin nor rifampin was associated with reduced infection relapse; 1 study found that rifampin treatment was associated with longer hospitalizations (mean, 31.3 vs 42.3 days; P < .001). Comparative safety outcomes were rarely reported, but 1 study found rifampin to be associated with hepatoxicity, nephrotoxicity, and DDIs, leading to treatment discontinuation in 31% of patients.

CONCLUSIONS

The existing clinical data do not suggest a benefit of either adjunctive gentamicin or rifampin in staphylococcal PVE. Given that other studies also suggest these agents add nephrotoxicity, hepatoxicity, and risk of DDIs without benefit in staphylococcal endovascular infections, we suggest that recommendations for gentamicin and rifampin in PVE be downgraded and primarily be used within the context of clinical trials.

Evidence of clinical impact supports a new petition for Medicare coverage of 18F-FDG-PET/CT in the evaluation of Staphylococcus aureus bacteremia: a focused literature review and call to action

Staphylococcus aureus bacteremia (SAB) causes considerable morbidity and mortality and requires comprehensive assessment for metastatic infection. The roles of routine imaging beyond echocardiography in SAB, including 18F-FDG-PET/CT, remain contentious. We performed a literature review of studies reporting impact of 18F-FDG-PET/CT on the clinical management or outcomes of SAB published through 3/1/2022. We identified seven observational studies, in which 18F-FDG-PET/CT frequently identified metastatic foci of infection, revealed foci undetected by prior investigations, led to additional source control procedures, and was associated with fewer infection relapses and lower mortality. Calculated numbers needed to treat (NNTs) for receipt of 18F-FDG-PET/CT were 7-9 to change antimicrobial therapy, 10-27 to lead to an additional source control procedure, and 4-8 to prevent death. These data are comparable to the evidence for clinical impact of other diagnostic modalities accepted as standard of care in SAB, and form a compelling basis for advocacy to expand access to 18F-FDG-PET/CT.

The History of Antibiotic Treatment of Osteomyelitis

Antibiotic treatment of osteomyelitis has evolved substantially over the past 80 years. Traditional teachings (eg, that antimicrobials must be given parenterally, selected based upon ratios of achieved bone vs serum drug levels, and continued for 4–6 weeks) are supported by limited data. New studies are challenging this dogma, however. In this review, we seek to contextualize the discussion by providing a narrative, chronologic review of osteomyelitis treatment spanning the pre-antibiotic era through the present day and by describing the quality of evidence supporting each component of traditional osteomyelitis therapy.

Dialysis Catheter-related Bloodstream Infections in Patients Receiving Hemodialysis on an Emergency-only Basis: A Retrospective Cohort Analysis

BACKGROUND

An estimated 6500 undocumented immigrants with end-stage renal disease (ESRD) live in the United States. Those living in states that do not provide undocumented immigrants scheduled hemodialysis receive intermittent hemodialysis only when life-threatening conditions arise. Little is known about catheter-related bloodstream infections (CRBSIs) in this population.

METHODS

We conducted a retrospective cohort study of emergency-only hemodialysis patients in the Harris Health System in Houston, Texas, between January 2012 and December 2015. We assessed CRBSI risk factors including demographics, comorbidities, and duration and frequency of hemodialysis. We investigated the microbiologic etiology of these infections, rates of recurrent CRBSI, and associated morbidity and mortality.

RESULTS

The cohort included 329 patients; 90% were Hispanic, 60% had diabetes, and the average age was 51 years. A total of 101 CRBSIs occurred, with a rate of 0.84 infections per 1000 catheter-days. Cirrhosis and duration of hemodialysis during the study period were associated with increased risk of CRBSI. Seventeen CRBSIs were recurrent; infection with gram-positive bacteria predicted recurrence. Adherence to catheter-related infection guidelines was improved by infectious diseases consultation and associated with fewer recurrent infections. CRBSI was associated with prolonged hospitalization (mean, 15 days), composite complication rate of 8%, and a 4% mortality rate.

CONCLUSIONS

Patients receiving emergency-only hemodialysis via tunneled catheters have a high CRBSI rate compared with infection rates previously reported in patients receiving scheduled maintenance hemodialysis. Increased CRSBI risk likely contributes to the increased morbidity and mortality seen in ESRD patients receiving emergency-only hemodialysis.

Bowel Perforation Resulting in Necrotizing Soft-Tissue Infection of the Abdomen, Flank, and Lower Extremities

BACKGROUND

Fournier's gangrene is a necrotizing soft-tissue infection (NSTI) that often originates from a break in bowel integrity and affects the perineum, anus, or genitalia. Although the pathogenesis is similar, NSTI caused by a break in bowel integrity less commonly presents as infection of other sites.

OBJECTIVE

To characterize NSTIs originating from bowel perforation and presenting as infection of the abdominal wall, flank, or thigh but that largely spare the perineum, anus, and genitalia.

METHODS

We describe a characteristic case and summarize findings from 67 reported cases.

RESULTS

The causes of bowel injury included trauma (29%), perforated appendicitis (23%), perforated diverticulitis (16%), and perforation of a gastrointestinal tract cancer (16%). The symptomatic prodrome is indolent and nondescript. Most patients have polymicrobial infections and require antibiotic therapy combined with serial surgical debridements. Because the presentation differs from that of typical Fournier's gangrene, recognition of NSTI was delayed in the reported cases, and the associated bowel perforation often was overlooked, leading to delayed surgical treatment. As a result, the mortality rate was >33%, far exceeding that of typical Fournier's gangrene. Delays in diagnosis or surgical intervention predict a poor outcome.

CONCLUSIONS

An NSTI resulting from bowel perforation can present in an atypical fashion carrying significant morbidity and mortality rates. Delayed diagnosis and treatment of this condition is associated with a poor outcome.