Stewardship / Resistance Scan for Aug 31, 2017

Respiratory viral testing for pneumonia
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Antiseptic resistance genes in Turkey

Study: Respiratory viral testing has small effect on antibiotics for pneumonia

Molecular respiratory viral testing had minimal impact on reducing antibiotic utilization among viral pneumonia patients, according to a study yesterday in the American Journal of Infection Control.

In the multisite cohort study of 190 patients diagnosed with community-associated pneumonia (CAP), researchers compared the clinical characteristics and antibiotic therapy of patients who tested positive on a polymerase chain reaction respiratory viral panel (PCR-RVP) with those who tested negative. PCR-RVP can detect multiple viral pathogens and gives physicians the ability to make a specific diagnosis of viral pneumonia, which in theory should lead to reduced antibiotic use.

Of the 190 patients diagnosed with CAP, 108 (57%) were RVP positive for viral pathogens and 82 (43%) were RVP negative. Clinical outcomes between the two groups were similar. But while RVP-positive patients were less likely to be continued on antibiotic therapy for longer than 48 hours compared to RVP-negative patients (72% vs. 90%), the median duration of antibiotic treatment in the two groups was not significantly different (3 days vs. 4 days).

"Our study suggests that physicians hesitate to discontinue antibiotic therapy even when patients are found to have viral pneumonia using a highly sensitive and specific PCR methodology," the authors of the study write, adding that potential coinfection with bacterial pathogens is a common clinical challenge.

They suggest combining PCR-RVP testing with testing for procalcitonin (PCT), a biomarker that can help differentiate between bacterial and viral pneumonia, could help reassure physicians that patients with viral pneumonia do not have a bacterial superinfection, and help them identify which patients may be candidates for discontinuing antibiotic therapy.
Aug 30 Am J Infect Control abstract

 

Turkish data reveal high level of Staphylococcus antiseptic resistance genes

Researchers in Turkey report a high frequency of antiseptic resistance genes in clinical staphylococci samples in a study yesterday in Antimicrobial Resistance and Infection Control.

In the study, 69 Staphylococcus spp. (including methicillin-resistant S aureus, methicillin-susceptible S aureus, methicillin-resistant coagulase-negative staphylococci, and methicillin-susceptible coagulase-negative staphylococci) and 69 Enterococcus spp. were collected from various clinical samples at a university hospital from January 2010 to March 2011. Researchers then conducted antiseptic and antibiotic susceptibility tests and analyzed antiseptic resistance genes using the polymerase chain reaction method. It has previously been reported that antiseptic resistance genes caused tolerance to a variety of biocidal agents used to prevent infections in hospitals.

Overall, antiseptic resistance genes were found in 49 of the 69 staphylococci isolates, and none of the enterococci isolates. Among the 49 staphylococci isolates positive for an antiseptic resistance gene, qacA/B genes were the most dominant (28/49), followed by qacJ (18/49), qacG (16/49), and smr (11/49) genes. The frequency of qacA/B and smr genes was higher in coagulase-negative staphylococci (CNS) when compared with S aureus isolates, while the frequency of qacG and qacJ genes was higher in S aureus than those of CNS.

The researchers also found a statistically significant association between the presence of antiseptic resistance genes and the minimum inhibitory concentration of benzalkonium chloride (BAC), a biocidal agent commonly used in hospitals. But no significant relationship was found between the presence of antiseptic resistance genes and antibiotic resistance.

"Further studies are needed to revise the biocide policy and to support infection control programs to avoid the development of new resistance mechanisms," the authors write.
Aug 31 Antimicrob Resist Infect Control study

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