Journal Club
In this feature, a panel of IDSA members identifies and critiques important new studies in the current literature that have a significant impact on the practice of infectious diseases medicine.
- Improving Vaccination Rates: Can Legislation Have an Impact?
- Placing PICCs for Antibiotics: Potential Undue Risks
- Fluoroquinolone Prophylaxis and Meropenem Non-susceptible aeruginosa: A Cautionary Tale
Click here for the previous edition of Journal Club. For a review of other recent research in the infectious diseases literature, see “In the Literature,” by Stanley Deresinski, MD, FIDSA, in each issue of Clinical Infectious Diseases.
Improving Vaccination Rates: Can Legislation Have an Impact?
Reviewed by Terri Stillwell, MD
Presently, the U.S. is experiencing the greatest number of measles cases since 1992. In an effort to combat this public health emergency, many states are looking towards tightening vaccine requirements. The state of California was one of the first to eliminate personal-belief exemptions from vaccination requirements for school entry with the passage of Senate Bill No. 277 (SB277) back in 2015. In a recent article in Pediatrics, authors examined the impact SB277 has had on vaccination rates.
In this study, the vaccination status of kindergarteners in 2015, the year prior to the implementation of SB277, was compared to the status of kindergarteners in 2016 and 2017. Using publicly reported data, those up-to-date on vaccinations versus those not, and exemptions used, were analyzed.
Overall, from 2015 to 2016 the rate of not up-to-date kindergarteners decreased from 7.15 percent to 4.42 percent. However, while the rate of personal belief exemptions decreased from 2.37 percent in 2015 to < 0.01 percent in 2017, there was a nearly four-fold increase in medical exemptions (0.17 percent to 0.73 percent). Additionally, 1.08 percent of kindergarteners were noted to be exempt due to homeschooling, having educational programs that do not involve classroom-based learning, or requiring special education. Also of note, the overall rate of not up-to-date kindergarteners slightly increased in the second year after the law was passed, from 4.42 percent (2016) to 4.87 percent (2017).
While SB277 did result in a decrease in the number of not up-to-date kindergarteners, it is important to note that the decrease in personal belief exemptions appears to have been countered by an increase in medical exemptions and other non-medical exemptions allowed by the law. The authors refer to these as “replacement” exemptions. Additional legislative measures are likely needed to have a sustainable impact on vaccination rates.
(Delamater et al. Pediatrics. 2019;143(6):e20183301.)
Placing PICCs for Antibiotics: Potential Undue Risks
Reviewed by Kelly Cawcutt, MD, MS
The placement of peripherally inserted central catheters (PICCs) is common practice for intravenous (IV) antibiotic needs. However, we may be inadvertently placing certain patients at higher risks for complications. A recent study by Paje et al. published in Annals of Internal Medicine assessed the frequency of PICC placement among patients with stage 3b or greater chronic kidney disease (CKD), a practice discordant with current guidelines.
This prospective study included data from over 20,000 adult patients across 52 hospitals participating in the Michigan Hospital Medicine Safety Consortium between 2013 and 2016. The most common indication for PICC placement was for IV antibiotics (37.6 percent). Of patients with PICCs, 23.1 percent had CKD stage 3b or greater, with an increased likelihood of PICC placement in the setting of CKD within the ICU as compared to the wards (32.1 percent vs 18.9 percent, respectively). Further, most PICC lines placed in patients with CKD were removed prior to hospital discharge (67.2 percent), with 25.8 percent of these lines having an indwell time of less than 5 days. Complications developed in 17.8 percent of all PICCs, with higher rates among patients in the ICU and those with CKD.
This study is incredibly important as it highlights the need to assess potential risks of placing a PICC, in addition to the need for IV antibiotics, particularly among those with CKD. The high rate of PICC placement among CKD patients limits their future potential for arteriovenous fistula placement, the lowest risk hemodialysis access for central line-associated bloodstream infection and other complications. Further, the short duration of indwell time in PICCs suggests potential alternative IV access, or other potential treatment options, could have been pursued. There is a great opportunity for the ID community to improve vascular access device choice, in concordance with current guidelines, among CKD patients requiring antibiotics.
(Paje et al. Ann Intern Med. 2019;171(1):10-18.)
Fluoroquinolone Prophylaxis and Meropenem Non-susceptible P. aeruginosa: A Cautionary Tale
Reviewed by Jennifer Brown, MD
Fluoroquinolone exposure can drive carbapenem resistance in Pseudomonas aeruginosa by down-regulating the carbapenem entry porin OprD and by up-regulating meropenem efflux pumps. Little is known about the impact of these resistance mechanisms on the emergence of carbapenem-resistant P. aeruginosa in patients with hematologic malignancies (HMs) and hematopoietic cell transplants (HCTs)—patients who often receive fluoroquinolone prophylaxis. To address this knowledge gap, Hakki et al. retrospectively reviewed P. aeruginosa bloodstream infections in adult patients with HM or HCT at an academic medical center. They also conducted whole-genome sequencing and phenotypic assessments of meropenem efflux pump activity on select isolates. Their results appear in Clinical Infectious Diseases.
Overall, 55 episodes of P. aeruginosa bacteremia among 51 patients were evaluated; 26 (47.3 percent) occurred during fluoroquinolone prophylaxis and 29 (52.7 percent) in the absence of fluoroquinolone prophylaxis. Of the fluoroquinolone-breakthrough P. aeruginosa isolates, none were susceptible to ciprofloxacin, and 4/26 (15.4 percent) were susceptible to meropenem. Of the isolates from patients who received non-fluoroquinolone or no prophylaxis, 21/29 (72.4 percent) were susceptible to ciprofloxacin, and 21/29 (72.4 percent) were susceptible to meropenem. Breakthrough bacteremia during fluoroquinolone prophylaxis was not associated with reduced susceptibility to anti-pseudomonal β-lactams or aminoglycosides. In a multivariate analysis that included fluoroquinolone breakthrough bacteremia and hospital-associated infection, only fluoroquinolone breakthrough was an independent predictor of meropenem-nonsusceptibility.
When whole-genome sequencing was performed on 23 meropenem-nonsusceptible isolates, none were found to contain carbapenemase genes; all had oprD inactivating mutations. Also, when tested by phenotypic analysis for efflux pump activity, all isolates had decreased meropenem minimum inhibitory concentrations when exposed to an efflux pump inhibitor.
It should be noted that phylogenetic analysis revealed some clusters of closely related isolates from different patients in this study. Nonetheless, this work highlights that patients with HMs and HCTs who receive fluoroquinolone prophylaxis are at risk for bloodstream infections with meropenem-nonsusceptible P. aeruginosa.
(Hakki et al. Clin Infect Dis. 2019;68(12):2045-2052.)