Polymyxin B and colistin-the economic burden of nephrotoxicity against multidrug resistant bacteria

A Systematic Review of the Costs of Drug-Associated Acute Kidney Injury and Potential Cost Savings With Nephrotoxin Stewardship Prevention Strategies

There is a scarcity of information related to the financial impact of acute kidney injury (AKI), and even more so the economics of drug-associated AKI (D-AKI). Our goal was to provide a comprehensive summary of the economic burden of D-AKI by evaluating the costs of D-AKI compared to not developing AKI and cost savings associated with nephrotoxin stewardship approaches. Following the PRISMA guidelines, a literature search was conducted using PubMed to identify articles from database inception through November 2023. The main outcomes included AKI incidence, resource use, and cost of nephrotoxin stewardship programs/D-AKI event or no event. Key findings were summarized based on whether the study compared the cost of D-AKI vs. no AKI or identified potential cost savings associated with a nephrotoxin stewardship method to prevent D-AKI or worsening D-AKI. All costs were adjusted to USD2023. Twenty-five studies met the inclusion criteria. Eight studies compared the cost of D-AKI to no AKI. Total admission costs of patients who developed D-AKI ranged from $47,696 to $173,569. Nineteen studies implemented nephrotoxin stewardship with 12 substituting a less nephrotoxic drug; five using therapeutic drug monitoring and two altering drug dosing to limit exposure. Overall, these prevention strategies ranged from $5,171 to $364,973 in total medical cost savings and $17 to $942 in total cost savings per patient-day. The in-hospital economic impact of D-AKI is substantial. Implementing nephrotoxin stewardship strategies to reduce D-AKI is associated with cost savings. Institutions should adopt strategic and efficient nephrotoxin stewardship programs to optimize patient care and reduce costs.

Oral doxycycline to carbapenem-resistant Acinetobacter baumannii infection as a polymyxin-sparing strategy: results from a retrospective cohort

Acinetobacter baumannii infection presents a high mortality rate and few therapeutic options. This study aimed to evaluate clinical-microbiological characteristics and prognosis factors of patients diagnosed with A. baumanni. infections treated with oral doxycycline. A retrospective cohort of hospitalized patients with confirmed Acinetobacter spp. infection between 2018 and 2020 receives at least 3 days of oral doxycycline. Clinical and microbiological data were evaluated, including the outcome and molecular characterization of A. baumannii. Doxycycline minimal inhibitory concentrations were evaluated by the broth dilution method. One hundred patients were included with a median age of 51 years. The leading site of infection was pulmonary (n = 62), followed by the soft tissues and skin (n = 28). A. baumannii resistant to carbapenem was found on 94%. The gene blaOXA-23 and blaOXA-51 were amplified in all recovered isolates of A. baumannii (n = 44). Doxycycline MIC50 and MIC90 were 1 µg/mL and 2 µg/mL, respectively. Death rate at 14 days and 28 days of follow-up was 9% and 14%, respectively. The prognostic factors related to death at end of follow-up were age > 49 years [85.7% vs. 46%, CI 95% 6.9 (1.4-32.6), P = 0.015] and hemodialysis [28.6% vs. 7%, CI 95% 5.33 (1.2-22.1), P = 0.021]. Patients treated with doxycycline to A. baumannii presented a relatively low death rate, and risk factors related to death were age and hemodialysis. Further and larger studies should compare polymyxin to doxycycline to better understand the differences between these therapeutic options.

Ferroptosis is involved in polymyxin B-induced acute kidney injury via activation of p53

Polymyxin B (PMB) is one of the most effective drugs for the treatment of multi-resistant and pan-resistant gram-negative infections. However, it can induce acute kidney injury (AKI), the mechanism of which has not yet been fully elucidated. In this study, RNA sequencing and in vitro and in vivo experiments demonstrated that PMB induced AKI by promoting ferroptosis. Moreover, the metallothionein-1 (MT-1) level was significantly increased in the AKI group and clinical cases revealed that iron and MT-1 levels in urine were significantly higher in patients with AKI than in those without AKI. To explore the mechanism of PMB induced ferroptosis, we silenced p53 in human kidney-2 (HK2) cells according to RNA sequencing, which showed that p53 was obviously enhanced in the PMB treated group. While PMB significantly enhanced Fe²⁺, lipid peroxidation, malondialdehyde (MDA), transferrin receptor protein 1 (TFR1), and arachidonate 12-lpoxygenase (ALOX12), decreased the survival rate, solute carrier family 7 member 11 (SLC7A11), glutathione peroxidase 4 (GPX4), and glutathione (GSH), downregulation of p53 reversed these effects, suggesting PMB induced ferroptosis by activating p53. Studies have shown p53 can promote ferroptosis by regulating the downstream factors SLC7A11 or TFR1. Further, we verified that silencing TFR1 expression as well as overexpression of SLC7A11 inhibited ferroptosis and significantly increased the survival rate of HK2 cells. Overall, PMB induces ferroptosis in renal tubular cells by activating p53 to reduce SLC7A11 expression and elevate TFR1, leading to AKI; MT-1 and iron levels in urine were significantly increased when PMB induced ferroptosis.

Dissemination of NDM-producing bacteria in Southern Brazil

BACKGROUND

The dissemination of NDM-1 carbapenemases (New Delhi Metallo-β-lactamase) is a global public health problem, mainly in developing countries. The aim of this study was to characterize the spread of NDM-producing bacteria in the Southern Brazilian states analyzing epidemiological, molecular, and antimicrobial susceptibility aspects.

METHODS

A total of 10,684 carbapenem-resistant isolates of Enterobacterales, Pseudomonas spp. and Acinetobacter spp. obtained from several hospitals in eight cities in Southern Brazil were screened, and 486 NDM-producing bacteria were selected.

RESULTS

The incidence varied from 0.5 to 77 cases/100.000 habitants. ST11, ST15, ST340 and ST674 were the most common in K. pneumoniae. A total of 5 plasmids were identified in one K. pneumoniae strain: Col440I, Col440II, IncFIA(HI1), IncFIB(K), IncFIB(pQil)/ IncFII(K), and IncR.

CONCLUSIONS

The number of patients with NDM-producing bacteria has increased in Southern Brazil, whose gene is present in different plasmids, explaining the expansion of this enzyme.

Pathogenesis of the Pseudomonas aeruginosa Biofilm: A Review

Pseudomonas aeruginosa is associated with several human infections, mainly related to healthcare services. In the hospital, it is associated with resistance to several antibiotics, which poses a great challenge to therapy. However, one of the biggest challenges in treating P. aeruginosa infections is that related to biofilms. The complex structure of the P. aeruginosa biofilm contributes an additional factor to the pathogenicity of this microorganism, leading to therapeutic failure, in addition to escape from the immune system, and generating chronic infections that are difficult to eradicate. In this review, we address several molecular aspects of the pathogenicity of P. aeruginosa biofilms.

Intravenous-to-oral antibiotic switch therapy: a cross-sectional study in critical care units

BACKGROUND

This study aimed to evaluate the oral switch (OS) stewardship intervention in the intensive care unit (ICU).

METHODS

This was a retrospective study with a convenience sample in two Brazilian ICUs from different hospitals in patients with sepsis receiving antibiotic therapy. The stewardship intervention included OS in patients diagnosed with sepsis when clinical stability was achieved. The primary outcome was overall mortality. Other variables evaluated were as follows: cost of antimicrobial treatment, daily costs of intensive care, acute kidney injury, and length of stay.

RESULTS

There was no difference in mortality between the OS and non-OS groups (p = 0.06). Length of stay in the ICU (p = 0.029) was shorter and acute kidney injury incidence (p = 0.032) and costs of antimicrobial therapy (p < 0.001) were lower in the OS group.

CONCLUSION

OS stewardship programs in the ICU may be considered a safe strategy. Switch therapy reduced the cost and shortened the length of stay in ICUs.