Top Infectious Disease News of the Week—January 13 2019

#5: Physician Management of Staphylococcus aureus Bacteremia

Staphylococcus aureus is the leading cause of community and health care-associated bacteremia, with an annual incidence of 38.2 to 45.7 per 100,000 person-years in the United States. Staphylococcus aureus bacteremia (SAB) has a 30-day mortality rate of 20% and health care costs per case can range from $37,868 to $67,439. Given the high prevalence and treatment costs of SAB, treatment becomes increasingly a topic of concern.

The involvement of infectious disease physicians in the treatment of patients with SAB has long been associated with significant improvements in patient outcomes and ensuring medical management follows best practice. In a new study, investigators set out to assess prescribing practices for the management of SAB and how diagnostic evaluation and medical management of adult patients varied.

The investigators utilized the Emerging Infections Network (EIN) to survey and assess how physicians treat SAB patients.

Read about physician management of Staphylococcus aureus Bacteremia.

#4: FDA Grants Fast Track Designation for C Diff Treatment

The US Food and Drug Administration (FDA) has granted Fast Track designation for ACX-362E, an investigational new treatment for C diff that is being developed by Acurx Pharmaceuticals, LLC.

ACX-362E is a targeted, narrow-spectrum orally administered antibacterial that is being evaluated in a recently launched phase 1 clinical trial. The antibiotic is one of multiple DNA polymerase IIIC inhibitors that Acrux is developing to treat bacterial infections.

"If approved, we believe our new antibacterial, ACX-362E, will be an important therapeutic alternative for patients with [C diff]. The Fast Track designation will allow Acurx to work more closely with the FDA to bring ACX-362E to physicians and patients as soon as possible." Robert J. DeLuccia, Co-Founder and Managing Partner of Acurx, said in a statement.

Read about the Fast Track Designation for a new C Diff treatment.

#3: Prescribed Opioid Use in Patients with HIV Tied to Elevated Pneumonia Risk

A new study led by Yale School of Medicine investigators has found that individuals with HIV who take prescription opioids for pain have an increased risk for developing community-acquired pneumonia.

Recent research has found that use of widely prescribed opioid analgesics such as codeine, morphine, and fentanyl can reduce natural killer cell activity, causing immunosuppressive effects and increasing the risk of serious infections. Individuals with HIV have used opioids to help manage chronic pain associated with the infection, but the new study published in the journal JAMA Internal Medicine investigated the association between use of prescribed opioids and community-acquired pneumonia requiring hospitalization among patients living with and without HIV.

For the investigation, the research team conducted a nested case-control study using data collected from January 1, 2000, through December 31, 2012, in the Veterans Aging Cohort Study, a prospective study of individuals with HIV who received care at a Veterans Health Administration (VA) medical center in the United States and used an uninfected group for comparison. Data from 25,392 participants were collected in the final analytic sample, including 14,906 people living with HIV and 10,486 uninfected patients, 98.9% of whom were male with a mean age of 55 years. There were 4246 cases of community-acquired pneumonia requiring hospitalization and 21,146 controls without community-acquired pneumonia.

Read about the elevated pneumonia risk in individuals with HIV who take prescribed opioids.

#2: FDA Approves Extended Use of Tdap Vaccine

The U.S. Food and Drug Administration has approved the use Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertussis Vaccine Adsorbed (Tdap) to include repeat vaccination to help protect against tetanus, diphtheria and pertussis. The vaccine is produced by Sanofi under the market name Adacel.

The approval was granted based on data from a study assessing the efficacy of the vaccine in a population of more than 1300 adults. Participants received either the Adacel vaccine or a tetanus-diptheria vaccine during a period 8-12 years following a dose of the Adacel vaccine. Results indicated that the second dose of Adacel vaccine in adults administered 8-12 years after a previous dose found no significant differences in reported adverse events between the 2 vaccine groups. In total 999 participants in the Tdap vaccine group (87.7%) and 328 participants in the Td vaccine group (88%) reported at least 1 injection-site reaction.

The approval has made the vaccine the first and only Tdap vaccine in the US approved for a repeat dose in individuals between the ages of 10 through 64 years, following 8 years or more after the first vaccination. The vaccine is also unique in that it is the only Tdap vaccine available in a syringe made without rubber latex, which may reduce the risk of the vaccine to individuals with allergies to latex.

Read about the extended approval of the Tdap vaccine.

#1: Larger HIV Reservoirs Found in Those with Clade B Subtype

A study team led by investigators from Simon Fraser University in Canada have made a key discovery on how viral factors, such as HIV subtypes, impact the size of the virus reservoirs in individuals with HIV. This finding provides new understanding on latent infections kept in check with combination antiretroviral therapy and may help shape research into eradicating and curing HIV infections.

While there is no cure for HIV, daily use of combination antiretroviral therapy medications suppresses the viral load in the blood and body fluids of those infected with HIV and reduces the risk of transmitting the virus; however, the viral reservoir remains in the body and can re-activate at any time if combination antiretroviral therapy is discontinued.

In a new study published in the Journal of Virology, investigators examined viral samples from 30 male study participants in Canada aged 22 to 59 years with recent HIV infections who were taking anti-HIV medications to understand factors that determine HIV reservoir size, or the number of cells that are latently infected with the HIV virus.

Investigators have previously studied how the various clades, or subtypes, of HIV impact disease onset, progression, symptoms, and related side effects. In Canada and the United States, HIV clade B is the most prevalent subtype.

Previous research has found that those with clade B have larger HIV reservoirs compared to individuals with HIV in Uganda with clade A or D, who can have HIV reservoirs that are 3 times smaller than those with clade B. Smaller reservoirs are associated with HIV remission and post-treatment virologic control, and early combination antiretroviral therapy initiation limits HIV reservoir size.

In the new study, investigators hypothesized that larger HIV reservoirs associated with clade B may be linked to an HIV gene called Nef, which encodes the HIV accessory protein that modulates key immune evasion and pathogenic functions and helps the virus evade immune defense in early infection.

Clade B viruses have a more functional version of Nef, which has led investigators to examine if this factor helps the virus establish larger reservoirs. For the study, investigators collected blood at baseline upon combination antiretroviral therapy initiation and again at 48 weeks following treatment initiation for immunologic, clinical, and reservoir size assessments.

Read about larger HIV reservoirs in individuals with clade B subtypes.