The Infectious Diseases Society of America, or IDSA, held its 2010 annual meeting from October 21 to 24 in Vancouver. The features below highlight some of the news emerging from the meeting.

» Comparing Treatments for Nosocomial Pneumonia
» Earlier Treatment for HIV-Infected Patients Lagging
» Analyzing Treatment Approaches for Cholera
» Veterans Less Likely to Be Tested for HIV
» The Link Between Smoking & Flu Risk in Children 

Comparing Treatments for Nosocomial Pneumonia

The Particulars: An estimated 1.7 million healthcare-associated infections are reported in American hospitals annually, and about 16% of those are associated with pathogens that are resistant to the antimicrobials traditionally used to treat them, including MRSA. Nosocomial pneumonia continues to be a significant cause of illness. When these infections are due to MRSA, treatment options are limited because there are few antibiotics that are effective against this resistant organism.

Data Breakdown: A phase 4 study trial compared the efficacy and safety of linezolid with vancomycin in the treatment of nosocomial pneumonia proven to be caused by MRSA. Patients were randomized to receive linezolid IV 600 mg every 12 hours or vancomycin 15 mg/kg every 12 hours over the course of 7 to 14 days; vancomycin doses could be titrated at the investigator’s discretion based on creatinine clearance and vancomycin trough levels. Clinical success rates at the end of study were 57.6% for patients treated with linezolid compared with 46.6% for patients treated with vancomycin in the per-protocol group, the primary endpoint. Treatment-related adverse events, serious adverse events and deaths were comparable for linezolid and vancomycin.

Take Home Pearl: Linezolid appears to achieve a statistically significantly higher clinical success rate when compared with vancomycin for the treatment of nosocomial pneumonia proven to be caused by MRSA.

Earlier Treatment for HIV-Infected Patients Lagging [back to top]

The Particulars: An estimated 1.7 million healthcare-associated infections are reported in American hospitals annually, and about 16% of those are associated with pathogens that are resistant to the antimicrobials traditionally used to treat them, including MRSA. Nosocomial pneumonia continues to be a significant cause of illness. When these infections are due to MRSA, treatment options are limited because there are few antibiotics that are effective against this resistant organism.

Data Breakdown: A phase 4 study trial compared the efficacy and safety of linezolid with vancomycin in the treatment of nosocomial pneumonia proven to be caused by MRSA. Patients were randomized to receive linezolid IV 600 mg every 12 hours or vancomycin 15 mg/kg every 12 hours over the course of 7 to 14 days; vancomycin doses could be titrated at the investigator’s discretion based on creatinine clearance and vancomycin trough levels. Clinical success rates at the end of study were 57.6% for patients treated with linezolid compared with 46.6% for patients treated with vancomycin in the per-protocol group, the primary endpoint. Treatment-related adverse events, serious adverse events and deaths were comparable for linezolid and vancomycin.

Take Home Pearl: Linezolid appears to achieve a statistically significantly higher clinical success rate when compared with vancomycin for the treatment of nosocomial pneumonia proven to be caused by MRSA.

Analyzing Treatment Approaches for Cholera [back to top]

The Particulars: Ciprofloxacin has been a primary treatment for cholera, but recent research suggests that it has begun to lose its efficacy against the disease. Single doses of ciprofloxacin in 1993-94 had had clinical and bacteriological success rates of 93% and 97%, respectively, but the respective rates were 27% and 10% by 2003-04. Administering multiple doses of ciprofloxacin had since correlated with improved clinical and bacteriological success rates. A study sought to determine if azithromycin could be an effective replacement for ciprofloxacin.

Data Breakdown: Researchers enrolled 246 men with cholera and randomly assigned them to get either a single 1-g dose of azithromycin or six doses of ciprofloxacin, orally every 12 hours for 3 days. Clinical success—defined as no watery stool within 48 hours of starting the drug—was seen in 63% of azithromycin patients and 44% of those getting ciprofloxacin. Bacteriological success—defined as no cholera bacteria in the stool after 48 hours of starting the drug—was seen in 68% of those on azithromycin and 45% of those getting ciprofloxacin. Patients on azithromycin had significantly fewer stools and lower stool volume.

Take Home Pearls:A single dose of azithromycin appeared to outperform six doses of ciprofloxacin for the treatment of cholera. If supported in future investigations, administering single-dose azithromycin to patients hospitalized with cholera may enable quicker discharges and enhance adherence to therapies.

Veterans Less Likely to Be Tested for HIV [back to top]

The Particulars: The CDC has recommended HIV testing for all persons aged 13 to 64 or pregnant women since 2006. However, there may still be some stigma involved with HIV that prevents physicians from asking patients to undergo an HIV test. It is important to test and identify HIV-infected individuals so that they can receive treatment. Little is known about HIV testing rates in Veterans Affairs (VA) healthcare systems, which are responsible for providing healthcare for 67 million Americans.

Data Breakdown: A study was conducted to determine HIV testing rates for VA health systems. Of the 5.7 million outpatients seen in the VA health system in 2009, only 9.2% had ever been tested for HIV. Overall, just 2.5% of VA outpatients were tested for HIV in 2009. In the District of Columbia and New York, where HIV prevalence has been historically high, only 21.6% and 11.8% of VA outpatients, respectively, had ever been tested for HIV. In places where HIV prevalence is low, such as Utah, just 2.7% of outpatients in the VA facilities there have been tested for HIV.

Take Home Pearls: There appears to be a slow uptake of HIV testing within VA health systems. Testing levels were low even in areas where HIV has historically had a large prevalence.

The Link Between Smoking & Flu Risk in Children [back to top]

The Particulars: Previous research has examined the possible association between exposure to smoking and a child’s risk of needing inpatient care for influenza. Many other complications of indoor smoking have been demonstrated in the past few years, but an association between exposure to smoking and the risk of a child needing inpatient care for influenza has not been demonstrated.

Data Breakdown: A large retrospective case-control 3-year data analysis was conducted, analyzing more than 1,300 laboratory-confirmed cases of child influenza which were collected by 10 sites in the CDC’s Emerging Infections Program. A serious case of flu was defined as hospital admission within 14 days of laboratory-confirmed influenza. Researchers found that the odds of children developing influenza were doubled if the mother was 26 or younger. The risk was increased if the child’s shots were not up to date. If more than half of household members smoked, the child’s risk of needing inpatient care was doubled. The risk was similar to having any pulmonary condition, including asthma. If the child was not fully vaccinated for the flu, having any household member immunized was protective.

Take Home Pearls: Having smokers in the house appears to increase the risk that a young child with influenza will need inpatient care. Other risk factors for serious cases of influenza included having a younger mother and not being up to date on vaccinations.

References

For more information on these items and other research that was presented at IDSA’s 2010 annual meeting, go to http://www.idsociety.org/Content.aspx?id=15991.