Stewardship / Resistance Scan for Dec 29, 2017

Bactericidal vs bacteriostatic drugs
HAI and medical gear

Review challenges the 'static vs cidal' dogma

Data from high-quality, randomized controlled trials show that bactericidal antibiotics are not intrinsically superior to bacteriostatic antibiotics, researchers from the University of Southern California School of Medicine report in a new paper in Clinical Infectious Diseases.

To test the common belief that bactericidal antibiotics (agents that kill or eliminate bacteria) are more effective than bacteriostatic antibiotics (agents that halt bacterial growth), the researchers conducted a systematic review of all randomized controlled trials published from January 1985 through September 2017 that compared clinical outcomes of bactericidal versus bacteriostatic antibiotics when treating serious or life-threatening invasive infections. They identified 56 trials to include in the review.

Of the 56 trials identified, 49 (81%) found no significant difference in efficacy between bacteriostatic and bactericidal agents, including for potentially highly lethal infections, such as typhoid fever, pneumonia, plague, or bacteremia. Furthermore, six of the trials showed that the bacteriostatic agent was more effective than the bactericidal agents.

Only one trial, comparing tigecycline with imipenem for the treatment of ventilator-associated pneumonia, found that a bactericidal agent was superior in efficacy. But pharmacologic analysis of that trial determined that the inferiority of the bacteriostatic agent (tigecycline) was based on the dose being too low; when the dose of tigecycline was doubled, efficacy was similar to imipenem.

The authors of the review say the available data suggest that other drug characteristics, such as optimal dosing, pharmacokinetics, and tissue penetration may be more important drivers of clinical efficacy.

"While it seems intuitive that antibiotics that more rapidly kill bacteria should be more clinically effective, a systematic review of randomized controlled trials does not support this assertion," the authors write. "It is time to abandon the notion that bactericidal agents are intrinsically more effective than bacteriostatic agents."
Dec 26 Clin Infect Dis abstract


Study probes role of portable medical equipment in pathogen spread

A small study conducted at a Veteran's Affairs hospital in Texas suggests that portable medical equipment (PME) could play an important role in the transmission cycle of healthcare-associated infections, researchers from the Texas Veterans Health Care System reported yesterday in BMC Infectious Diseases.

In the study, research staff observed different patient-care events over six different 24-hour periods on six different hospital units. The observers followed one healthcare worker for their entire shift, documenting every time they touched a patient or a surface—including hard surfaces, bedding, and PME such as computers on wheels (COW), vitals machines, and IV infusion pumps. Each encounter was recorded as a sequence of events and analyzed using sequence analysis. The purpose of the study was to investigate the patterns and sequence of touch events among healthcare workers, patients, surfaces, and equipment in the hospital environment.

The most commonly touched items in patient rooms were the patients with 850 touches, COW (634), bedrails (375), and IV pumps. Sequence analysis revealed that touching the patient and then the bedrail was the most common sub-sequence (occurring in 28.1% of all sequences). Touching the COW and then the patient was the most common sub-sequence between PME and patient (22.6% of all sequences), followed by touching the patient and then the COW (20.4% of all sequences), and touching the patient and then the IV pump (16.1% of all sequences).

The researchers also observed that hand hygiene was below expectations and that gloves were used in only about half the encounters. In addition, 5 of 48 COWs (10.4%) were contaminated with methicillin-resistant Staphylococcus aureus.

"PME, particularly COW and IV pump, are highly touched items and were common in sub-sequences that involved the patient, possibly contributing to higher pathogen transmission risk," the authors write. "Disinfection of PME, preferably in between patient interactions, may potentially be necessary, along with optimal hand hygiene, to reduce the possibility of transmission between patients."
Dec 28 BMC Infect Dis study

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