Ceftazidime-Avibactam versus Colistin for the Treatment of Infections Due to Carbapenem-Resistant Enterobacterales: A Multicenter Cohort Study

Treatment of a challenging NDM and OXA-48-producing Klebsiella pneumoniae causing skin and soft tissue infection and exhibiting resistance to the combination of Ceftazidime-Avibactam and Aztreonam: A case report

Carbapenem-resistant Enterobacterales (CRE) pose a significant public health concern. CRE could be carbapenamse producers or non-producers. In the Kingdom of Saudi Arabia, bla OXA-48 and bla NDM represent the majority of carbapenemase isolates. There are very limited treatment options for carbapenemase-producing CRE caused by bla NDM. Ceftazidime-avibactam plus aztreonam (CZA-ATM) or cefiderocol as monotherapy are considered the treatment of choice for these infections. Here, we report a case of a 70-year-old man presented with surgical site infection of above knee amputation stump. The cultures revealed carbapenem-resistant Klebsiella pneumoniae positive for bla NDM and bla OXA-48 resistant to CZA-ATM therapy and intermediate susceptibility to tigecycline. He was started on CZA-ATM both adjusted for renal function, and high dose tigecycline with daily wound dressing and irrigation. By day 20 of the antibiotic regimens, he had clinical and microbiological cure based on repeated wound cultures. This case identifies a rare incidence of CRE skin and soft tissue infection positive for bla NDM and bla OXA-48 resistant to CZA-ATM in a background of limited targeted options, but successfully treated with CZA-ATM and high-dose tigecycline. Such therapeutic approach might be useful in few circumstances when no other antibiotic options are available to treat extensively drug-resistant Klebsiella pneumoniae.

Ceftazidime/avibactam versus polymyxin B in carbapenem-resistant Klebsiella pneumoniae infections: a propensity score-matched multicenter real-world study

OBJECTIVES

In this retrospective observational multicenter study, we aimed to assess efficacy and mortality between ceftazidime/avibactam (CAZ/AVI) or polymyxin B (PMB)-based regimens for the treatment of Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections, as well as identify potential risk factors.

METHODS

A total of 276 CRKP-infected patients were enrolled in our study. Binary logistic and Cox regression analysis with a propensity score-matched (PSM) model were performed to identify risk factors for efficacy and mortality.

RESULTS

The patient cohort was divided into PMB-based regimen group (n = 98, 35.5%) and CAZ/AVI-based regimen group (n = 178, 64.5%). Compared to the PMB group, the CAZ/AVI group exhibited significantly higher rates of clinical efficacy (71.3% vs. 56.1%; p = 0.011), microbiological clearance (74.7% vs. 41.4%; p < 0.001), and a lower incidence of acute kidney injury (AKI) (13.5% vs. 33.7%; p < 0.001). Binary logistic regression revealed that the treatment duration independently influenced both clinical efficacy and microbiological clearance. Vasoactive drugs, sepsis/septic shock, APACHE II score, and treatment duration were identified as risk factors associated with 30-day all-cause mortality. The CAZ/AVI-based regimen was an independent factor for good clinical efficacy, microbiological clearance, and lower AKI incidence.

CONCLUSIONS

For patients with CRKP infection, the CAZ/AVI-based regimen was superior to the PMB-based regimen.

Real-world utilization of ceftazidime/avibactam among inpatients in the national Veterans Affairs Healthcare System

PURPOSE

Multidrug-resistant (MDR) infections are challenging to treat due to underlying patient conditions, pathogen characteristics, and high antibiotic resistance rates. As newer antibiotic therapies come to market, limited data exist about their real-world utilization.

METHODS

This was a national retrospective cohort study of ceftazidime/avibactam (approved in 2015) utilization among inpatients from the Veterans Affairs (VA) Healthcare System, from 2015 through 2021. Joinpoint regression was used to estimate time trends in utilization.

RESULTS

Ceftazidime/avibactam use increased by 52.3% each year (days of therapy per 1,000 bed days; 95% confidence interval, 12.4%-106.4%). We identified 1,048 unique predominantly male (98.3%) and white (66.2%; Black, 27.7%) patients treated with ceftazidime/avibactam, with a mean (SD) age of 71.5 (11.9) years. The most commonly isolated organisms were Pseudomonas aeruginosa (36.3%; carbapenem resistant, 80.6%; MDR, 65.0%) and Klebsiella species (34.1%; carbapenem resistant, 78.4%; extended-spectrum cephalosporin resistant, 90.7%). Common comorbid conditions included hypertension (74.8%), nervous system disorders (60.2%), diabetes mellitus (48.7%), and cancer (45.1%). Median time to ceftazidime/avibactam initiation from admission was 6 days, with a median of 3 changes in therapy before ceftazidime/avibactam initiation and a subsequent median length of inpatient stay of 14 days (median of 8 days of ceftazidime/avibactam therapy). Treatment heterogeneity was high, both before ceftazidime/avibactam initiation (89.6%) and during ceftazidime/avibactam treatment (85.6%), and common concomitant antibiotics included vancomycin (41.4%), meropenem (24.1%), cefepime (15.2%), and piperacillin/tazobactam (15.2%). The inpatient mortality rate was 23.6%, and 20.8% of patients had a subsequent admission with ceftazidime/avibactam treatment.

CONCLUSION

Utilization of ceftazidime/avibactam increased from 2015 to 2021 in the national VA Healthcare System. Ceftazidime/avibactam was utilized in complex, difficult-to-treat patients, with substantial treatment heterogeneity and variation in the causative organism and culture sites.

Ceftazidime-avibactam alone or in combination with Aztreonam versus Polymyxins in the management of carbapenem-Resistant Klebsiella pneumoniae nosocomial Infections (CAPRI study): a retrospective cohort study from South India

INTRODUCTION

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections commonly cause hospital-acquired infections. The study aimed to compare the outcomes of CRKP infections between patients receiving ceftazidime avibactam +/- aztreonam and polymyxins in a hospital setting with a high prevalence of New Delhi Metallo Beta Lactamase production.

METHODS

We conducted a retrospective cohort study from January 2020 to September 2022 in critically ill adult patients admitted to a non-COVID-19 medical intensive care unit with CRKP infection. The patients were followed up for a total of 30 days or death, whichever was later.

RESULTS

Of a total of 106 patients included in the study, 65 patients received polymyxins and 41 patients received ceftazidime-avibactam +/- aztreonam. Higher 30-day mortality was noted in the polymyxin group (56.9% vs. 29.2%, P = 0.005). The mean time to event (mortality) in ceftazidime-avibactam +/- aztreonam was 23.9 + 1.5 days which was significantly higher compared to polymyxins (17.9 + 1.2 days, p = 0.006). On Cox regression analysis, after adjusting for the covariates, the hazard ratio for time to event with the use of polymyxin was 2.02 (95% CI: 1.03-3.9).

CONCLUSION

Ceftazidime-avibactam + aztreonam is possibly associated with better clinical outcomes in patients infected with CRKP.

Ceftazidime-avibactam induced renal disorders: past and present

With the increasing prevalence of multidrug-resistant Gram-negative bacterial pathogens worldwide, antimicrobial resistance has become a significant public health concern. Ceftazidime-avibactam (CAZ-AVI) exhibited excellent in vitro activity against many carbapenemase-producing pathogens, and was widely used for the treatment of various complicated infections. CAZ-AVI is well tolerated across all dosing regimens, and its associated acute kidney injury (AKI) in phase II/III clinical trials is rare. However, recent real-world studies have demonstrated that CAZ-AVI associated AKI was more frequent in real-world than in phase II and III clinical trials, particularly in patients receiving concomitant nephrotoxic agents, with critically ill patients being at a higher risk. Herein, we reviewed the safety data related to renal impairment of CAZ-AVI, and discussed its pharmacokinetic/pharmacodynamic targets and dosage adjustment in patients with impaired renal function. This review aimed to emphasize the importance for healthcare professionals to be aware of this adverse event of CAZ-AVI and provide practical insights into the dosage optimization in critically ill patients with renal dysfunction.

Reviewing novel treatment options for carbapenem-resistant Enterobacterales

INTRODUCTION

Carbapenem resistant Enterobacterales (CRE) are a major threat to global health and hospital-onset CRE infections have risen during the COVID-19 pandemic. Novel antimicrobials are now available for the treatment of CRE infections. There remains an urgent need for new antimicrobials for CRE, especially for those producing metallo-β-lactamases.

AREAS COVERED

This article discusses previously published research supporting currently available novel antimicrobials for the treatment of CRE infections. Newer compounds currently being evaluated in clinical trials are covered. A literature search was conducted in PubMed over all available dates for relevant published papers and conference abstracts with the search terms, 'CRE,' 'carbapenem-resistant Enterobacterales,' 'β-lactam-β-lactamase inhibitor,' 'KPC,' 'NDM,' 'metallo-β-lactamase,' 'ceftazidime-avibactam,' 'meropenem-vaborbactam,' 'imipenem-cilastatin-relebactam,' 'cefiderocol,' 'eravacycline,' 'plazomicin,' 'taniborbactam,' 'zidebactam,' and 'nacubactam.'

EXPERT OPINION

Novel antimicrobials for CRE infections have been developed, most notably the β-lactam-β-lactamase inhibitor combinations, though treatment options for infections with metallo-β-lactamase producing Enterobacterales remain few and have limitations. Development of antibiotics with activity against metallo-β-lactamase producing Enterobacterales is eagerly awaited, and there are promising new compounds in clinical trials. Finally, more clinical research is needed to optimize and individualize treatment approaches, which will help guide antimicrobial stewardship initiatives aimed at reducing the spread of CRE and development of further resistance.

Use of Ceftazidime-Avibactam for Suspected or Confirmed Carbapenem-Resistant Organisms in Children: A Retrospective Study

Background

The incidence of carbapenem-resistant organism (CRO) infections is increasing in children. However, pediatric-specific treatment strategies present unique challenges. Ceftazidime/avibactam is a β-lactam/β-lactamase inhibitor combination, showing adequate efficiency against CRO isolates. However, clinical data on the efficacy of ceftazidime/avibactam in children are still lacking.

Methods

This was a retrospective study of children (aged <18 years) infected with confirmed or suspected carbapenem-resistant pathogens and treated with ceftazidime-avibactam at the First Affiliated Hospital of Zhengzhou University between 2020 and 2022.

Results

We identified 38 children aged 14 (5.0-16.3) years; 20 (52.6%) had hematologic malignancies. 25 children with confirmed CRO infections were administered ceftazidime-avibactam as targeted therapy. The median treatment was 10 (6.0-16.5) days. Among them, 24 had infections caused by carbapenem-resistant Enterobacterales (CRE) (18 carbapenem-resistant Klebsiella pneumoniae and six carbapenem-resistant Escherichia coli species) and one with carbapenem-resistant Pseudomonas aeruginosa strains. The source of infection was the bloodstream in 60.0% of the cases (15/25). The clinical response rate was 84.0% (21/25), and 30-day mortality rate was 20% (5/25). 13 children were administered ceftazidime-avibactam as empiric therapy for suspected infections. The median treatment was 8 (6.0-13.0) days. No deaths occurred and clinical response was achieved in 12 of the 13 patients (92.3%) who empirically treated with ceftazidime-avibactam.

Conclusion

Ceftazidime-avibactam is important for improving survival, and clinical response in children with infections caused by CRO.

Cost-effectiveness analysis of ceftazidime avibactam versus colistin in carbapenem-resistant enterobacteriaceae in Iran

INTRODUCTION

Ceftazidime avibactam (CA) is an effective treatment against carbapenem-resistant Enterobacteriaceae (CRE), but its cost-effectiveness is unclear. This study was performed to evaluate the cost-effectiveness of CA against the best available treatment colistin (Col) for patients with CRE-related infections in Iran.

METHODOLOGY

A model of a decision tree was designed to evaluate the cost-effectiveness of CA in CRE patients over a period of 5 years. The Iran health system was the perspective of the study, and the discount rates of 5.8% and 3% were considered for the data of cost and utility, respectively. The clinical inputs were obtained from a prospective observational study. We established the costs of medical services and medical tariffs of Iran's health system, and obtained the rate of medical service resources used by patients from specialists. The results of this model included the quality-adjusted life years (QALYs), increasing costs, and incremental cost-utility ratio (ICUR). We also performed the deterministic and probabilistic sensitivity analyses.

RESULTS

CA reduced the burden of related to treatment failure and the need for treatment of nephrotoxicity and chronic failure, whereas, the costs related to drug procurement and long-term care (due to longer survival) increased. Treatment with CA versus Col resulted in a 53% increase in QALYs and $425 in costs, leading to an ICUR equal to 798 $/QALYs. Sensitivity analyses proved the model's strength and indicated that the cost-effectiveness of CA can reach 88% when paying 1111 $/QALY. Budget impact analysis estimated CA regimen will increase the health system costs by $1,270,462 in 5 years.

CONCLUSION

In Iranian settings, CA can significantly increase the quality of life and patients' survival; therefore, in comparison to the Col drug regimen, CA is a cost-effective strategy.

Antibiotic Susceptibility Surveillance in the Punjab Province of Pakistan: Findings and Implications

Background and Objectives: The increase in antimicrobial resistance (AMR) across countries has seriously impacted the effective management of infectious diseases, with subsequent impact on morbidity, mortality and costs. This includes Pakistan. Antimicrobial surveillance activities should be mandatory to continually assess the extent of multidrug-resistant bacteria and the implications for future empiric prescribing. The objective of this retrospective observational study was to monitor the susceptibility pattern of microbes in Pakistan. Materials and Methods: Clinical samples from seven laboratories in Punjab, Pakistan were collected between January 2018 and April 2019, with Punjab being the most populous province in Pakistan. The isolates were identified and their antimicrobial susceptibility was tested using the Kirby-Bauer disc diffusion assay and micro broth dilution methods. The antibiotics assessed were those typically prescribed in Pakistan. Results: In total, 2523 bacterial cultural reports were studied. The most frequently isolated pathogens were Staphylococcus aureus (866, 34.3%), followed by Escherichia coli (814, 32.2%), Pseudomonas aeruginosa (454, 18.0%) and Klebsiella pneumoniae (269, 10.7%). Most pathogens were isolated from pus (1464, 58.0%), followed by urine (718, 28.5%), blood (164, 6.5%) and sputum (81, 3.2%). Conclusions: The findings suggest that current antimicrobial options are severally restricted in Pakistan due to the emergence of multidrug-resistant pathogens. This calls for urgent actions including initiating antimicrobial stewardship programs to enhance prudent prescribing of antibiotics. This includes agreeing on appropriate empiric therapy as part of agreed guidelines, in line with the WHO EML and AWaRe book, whilst awaiting culture reports. This is alongside other measures to reduce inappropriate antimicrobial prescribing and reverse the threat of rising AMR.

Outcome, risk factors and therapeutic strategies in carbapenem-resistant Gram-negative bacteraemia from Pakistan

Background

Carbapenem-resistant Gram-negative (CRGN) bacteraemia has high mortality and limited therapeutic options. We assessed the risk factors and outcome of CRGN bacteraemia treated with limited options.

Methods

A prospective cohort study done at a tertiary care hospital in Pakistan, from October 2021 to August 2022. All patients >18 years with CRGN bacteraemia were assessed for demographics, source, risk factors and treatment received. Outcome was assessed as bacterial clearance and all-cause mortality at Day 14 of bacteraemia.

Results

We included 175 patients. Median age was 45 years (IQR 30-58) and the majority of our patients were on haemodialysis (75%). We found 14 day mortality in 26.8% of our patients; in addition, microbiological clearance was achieved in 95%. The central line (49.7%) was the most common source and Klebsiella spp. (47%) the most common organism. On multivariate analysis, risk factors for mortality were Foley's catheter [aOR 2.7 (95% CI 1.1-6.5)], mechanical ventilation [aOR 5.1 (95% CI 1.6-15.8)] and Pitt bacteraemia score >4 [aOR 3.48 (95% CI 1.1-10.5)]. Source control was a significant protective factor [aOR 0.251 (95% CI 0.09-0.6)]. The majority received a colistin-based regimen with no difference in mortality between monotherapy and combination therapy.

Conclusions

Our cohort of CRGN bacteraemia is unique, comprising younger patients mostly on haemodialysis with a central line as the source of bacteraemia and we have found 14 day mortality of 27%. Colistin with various combinations can be an effective option in patients with renal failure having prompt source control.

Efficacy and safety of ceftazidime-avibactam versus polymyxins in the treatment of carbapenem-resistant Enterobacteriaceae infection: a systematic review and meta-analysis

OBJECTIVES

Carbapenem-resistant Enterobacteriaceae is increasingly recognised as a significant public health concern. Ceftazidime-avibactam (CAZ-AVI) and polymyxins are considered as the last therapeutic options worldwide. This is the first meta-analysis of recently published data to compare the clinical efficacy and safety of CAZ-AVI with polymyxins in the treatment of carbapenem-resistant Enterobacteriaceae infections.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Embase and the Cochrane Library were systematically searched, for publications in any language, from database inception to February 2023.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies comparing the clinical efficacy and safety of CAZ-AVI with polymyxins were included. Mortality, clinical success, microbiological eradication and nephrotoxicity were assessed as the main outcomes.

DATA EXTRACTION AND SYNTHESIS

Literature screening, data extraction and the quality evaluation of studies were conducted by two researchers independently, with disagreements resolved by another researcher. The Newcastle-Ottawa Scale was used to assess the bias risk for the included studies. Review Manager V.5.3 was employed for the meta-analysis.

RESULTS

The meta-analysis included seven retrospective and four prospective cohort studies with 1111 patients enrolled. The CAZ-AVI groups demonstrated a lower 30-day mortality (risk ratio (RR)=0.48, 95% CI of 0.37 to 0.63, I²=10%, p<0.0001) in nine studies with 766 patients; higher clinical success (RR=1.71, 95% CI 1.33 to 2.20, I²=35%, p<0.0001) in four studies with 463 patients; and lower nephrotoxicity in seven studies with 696 patients (RR=0.42, 95% CI 0.23 to 0.77, I²=35%, p<0.05). However, no significant difference in microbiological eradication rates was observed in 249 patients from two studies (RR=1.16, 95% CI 0.97 to 1.39, I²=0, p>0.05).

CONCLUSION

Available evidence suggested that CAZ-AVI treatment held a dominant position with respect to efficacy and safety compared with polymyxins in carbapenem-resistant Enterobacteriaceae infections. However, the analysis included only observational studies, and high-quality, large-scale, multicentre, double-blind randomised controlled trials are needed to confirm the advantage of CAZ-AVI.

What to Do with the New Antibiotics?

Multidrug-resistant Gram-negative bacteria-related infections have become a real public health problem and have exposed the risk of a therapeutic impasse. In recent years, many new antibiotics have been introduced to enrich the therapeutic armamentarium. Among these new molecules, some are mainly of interest for the treatment of the multidrug-resistant infections associated with Pseudomonas aeruginosa (ceftolozane/tazobactam and imipenem/relebactam); others are for carbapenem-resistant infections associated with Enterobacterales (ceftazidime/avibactam, meropenem/vaborbactam); and finally, there are others that are effective on the majority of multidrug-resistant Gram-negative bacilli (cefiderocol). Most international guidelines recommend these new antibiotics in the treatment of microbiologically documented infections. However, given the significant morbidity and mortality of these infections, particularly in the case of inadequate therapy, it is important to consider the place of these antibiotics in probabilistic treatment. Knowledge of the risk factors for multidrug-resistant Gram-negative bacilli (local ecology, prior colonization, failure of prior antibiotic therapy, and source of infection) seems necessary in order to optimize antibiotic prescriptions. In this review, we will assess these different antibiotics according to the epidemiological data.

Prevalence of silver resistance determinants and extended-spectrum β-lactamases in bacterial species causing wound infection: First report from Bangladesh

Background

The use of silver is rapidly rising in wound care and silver-containing dressings are widely used along with other antibiotics, particularly β-lactams. Consequently, concerns are being raised regarding the emergence of silver-resistance and cross-resistance to β-lactams. Therefore, this study aimed to determine the phenotypic and genotypic profiles of silver-resistance and extended-spectrum β-lactamases in isolates from chronic wounds.

Methods

317 wound swab specimens were collected from tertiary hospitals of Dhaka city and analysed for the microbial identification. The antibiotic resistance/susceptibility profiles were determined and phenotypes of silver resistant isolates were examined. The presence of silver-resistance (sil) genes (silE, silP, and silS) and extended-spectrum β-lactamases (ESBL) (CTX-M-1, NDM-1, KPC, OXA-48, and VIM-1) were explored in isolated microorganisms.

Results

A total of 501 strains were isolated with Staphylococcus aureus (24%) as the predominant organism. In 29% of the samples, polymicrobial infections were observed. A large proportion of Enterobacterales (59%) was resistant to carbapenems and a significantly high multiple antibiotic-resistance indexes (>0.2) were seen for 53% of organisms (P < 0.001). According to molecular analysis, the most prevalent types of ESBL and sil gene were CTX-M-1 (47%) and silE (42%), respectively. Furthermore, phenotypic silver-nitrate susceptibility testing showed significant minimum-inhibitory-concentration patterns between sil-negative and sil-positive isolates. We further observed co-occurrence of silver-resistance determinants and ESBLs (65%).

Conclusions

Notably, this is the first-time detection of silver-resistance along with its co-detection with ESBLs in Bangladesh. This research highlights the need for selecting appropriate treatment strategies and developing new alternative therapies to minimize microbial infection in wounds.

Impact of Positive Culture Reports of E. coli or MSSA on De-Escalation of Antibiotic Use in a Teaching Hospital in Pakistan and the Implications

Background

Antibiotic de-escalation is a key element of antimicrobial stewardship programs that restrict the spread and emergence of resistance. This study was performed to evaluate the impact of positive culture sensitivity reports of E. coli or Methicillin sensitive Staphylococcus aureus (MSSA) on de-escalation of antibiotic therapy.

Methods

This prospective observational study was performed on 256 infected patients. The samples were obtained principally from the pus of infected sites for the identification of pathogens and culture-sensitivity testing. The data were collected from patient medical files, which included their demographic data, sample type, causative microbe and antimicrobial treatment as empiric or definitive treatment based on cultures. Data were analyzed using SPSS.

Results

Of 256 isolated microbes, 138 (53.9%) were MSSA and 118 were E. coli (46.1%). MSSA showed 100% sensitivity to cefoxitin, oxacillin, vancomycin, fosfomycin, colistin and more than 90% to linezolid (95.3%), tigecycline (93.1%), chloramphenicol (92.2%) and amikacin (90.2%). E. coli showed 100% sensitivity to only fosfomycin and more than 90% to colistin (96.7%), polymyxin-B (95.1%) and tigecycline (92.9%). The high use of cefoperazone+sulbactam (151), amikacin (149), ceftriaxone (33), metronidazole (30) and piperacillin + tazobactam (22) was seen with empiric prescribing. Following susceptibility testing, the most common antibiotics prescribed for E. coli were meropenem IV (34), amikacin (34), ciprofloxacin (29) and cefoperazone+sulbactam (25). For MSSA cases, linezolid (48), clindamycin (30), cefoperazone+ sulbactam IV (16) and amikacin (15) was used commonly. Overall, there was 23% reduction in antibiotic use in case of E. coli and 43% reduction in MSSA cases.

Conclusion

Culture sensitivity reports helped in the de-escalation of antimicrobial therapy, reducing the prescribing of especially broad-spectrum antibiotics. Consequently, it is recommended that local hospital guidelines be developed based on local antimicrobial susceptibility patterns while preventing the unnecessary use of broad-spectrum antibiotics for empiric treatment.

Point Prevalence Survey of Antimicrobial Use during the COVID-19 Pandemic among Different Hospitals in Pakistan: Findings and Implications

The COVID-19 pandemic has significantly influenced antimicrobial use in hospitals, raising concerns regarding increased antimicrobial resistance (AMR) through their overuse. The objective of this study was to assess patterns of antimicrobial prescribing during the current COVID-19 pandemic among hospitals in Pakistan, including the prevalence of COVID-19. A point prevalence survey (PPS) was performed among 11 different hospitals from November 2020 to January 2021. The study included all hospitalized patients receiving an antibiotic on the day of the PPS. The Global-PPS web-based application was used for data entry and analysis. Out of 1024 hospitalized patients, 662 (64.64%) received antimicrobials. The top three most common indications for antimicrobial use were pneumonia (13.3%), central nervous system infections (10.4%) and gastrointestinal indications (10.4%). Ceftriaxone (26.6%), metronidazole (9.7%) and vancomycin (7.9%) were the top three most commonly prescribed antimicrobials among surveyed patients, with the majority of antibiotics administered empirically (97.9%). Most antimicrobials for surgical prophylaxis were given for more than one day, which is a concern. Overall, a high percentage of antimicrobial use, including broad-spectrums, was seen among the different hospitals in Pakistan during the current COVID-19 pandemic. Multifaceted interventions are needed to enhance rational antimicrobial prescribing including limiting their prescribing post-operatively for surgical prophylaxis.

Risk of Lichen Sclerosus and Lichen Planus in Patients Receiving Immune Checkpoint Inhibitors

INTRODUCTION

Immune checkpoint inhibitors (ICIs) are recommended for various types of cancer. On the other hand, these ICIs may cause immune-related adverse events (irAEs). Lichen sclerosus (LS) and lichen planus (LP) are two distinct phenotypes of irAEs that occur in a subset of patients treated with ICIs. These adverse effects have a detrimental effect on the patient's quality of life and treatment phases; however, the clinical evaluation and assessment of LS and LP remain uncertain. This study aims to assess and evaluate the risk of LS and LP associated with the use of ICIs via a systematic review of the literature and the USA FDA Adverse Events FAERS database.

METHOD

The study searched electronic databases such as PubMed, Medline, Cochrane, and Google Scholar for case reports on immune-checkpoint-inhibitor-associated lichen sclerosus and lichen planus published in English between inception and 31 December 2021. The FDA's adverse event reporting system (FAERS) database was also analyzed.

RESULTS

Thirty-eight case reports and two retrospective studies with a total of 101 patients, in addition to the FAERS data, were evaluated. More cases involved lichen planus (78.9%) than lichen sclerosis (21%). Nivolumab and pembrolizumab were most frequently reported with LS and LP, among other ICIs. Thirty-six out of thirty-eight patients with LS or LP experienced complete remission, while two patients experienced partial remission. Most of the cases had an excellent response to corticosteroids (92.1%), while the remainder had moderate (5.2%) and poor (2.6%) responses. Additionally, the reporting odds ratio (ROR) of the FAERS database indicated a favorable association for ICIs, the risk of LP, and LS. A stronger association was uniquely found between nivolumab and pembrolizumab.

CONCLUSION

There have been published case reports for these adverse events. Healthcare providers should be aware of the possibility of lichen sclerosis and lichen planus developing in patients receiving ICIs which could necessitate hospitalization or discontinuation. Regulatory agencies are advised to monitor the risks as a potential safety signal.

Evaluation of Dilution Susceptibility Testing Methods for Aztreonam in Combination with Avibactam against Enterobacterales

As multidrug and pan-resistance among Enterobacterales continue to increase, there is an urgent need for more therapeutic options to treat these infections. New β-lactam and β-lactam inhibitor (BLI) combinations have a broad spectrum of activity, but those currently approved do not provide coverage against isolates harboring metallo-β-lactamases (MBL). Aztreonam (ATM) and avibactam (AVI) in combination (ATM/AVI; AVI at 4 μg/mL fixed concentration) provides a similarly broad range of activity while maintaining activity against MBL-producing isolates. The in vitro susceptibility testing of ATM/AVI by standard methods was evaluated during development. This study investigated the impact of nonstandard testing conditions on the activity of ATM/AVI as observed during broth microdilution testing as well as the equivalency between agar dilution and broth microdilution MIC values when testing a diverse panel of Enterobacterales (N = 201). Nonstandard test conditions evaluated included inoculum density, atmosphere of incubation, media pH, varied medium cation concentrations, incubation time, varied serum concentrations, testing in pooled urine instead of media, addition of blood to the media, and the presence of surfactant. Generally, apart from low pH and high inoculum density, nonstandard testing parameters did not affect ATM/AVI broth microdilution MIC values. Correlation of MIC values obtained by agar dilution and broth microdilution resulted in an essential agreement of 97.0% for all tested Enterobacterales. Variation of standard testing conditions had little impact on broth microdilution MIC values for ATM/AVI. The correlation between broth microdilution and agar dilution MICs suggests both methods are reliable for determination of ATM/AVI MIC values. IMPORTANCE Increasing antibiotic resistance and emergence of pan-resistant isolates threaten the ability to control infections and to provide many other medical interventions such as surgery and chemotherapy, among others. New therapies are required to control emerging resistance mechanisms, including the increase in metallo-β-lactamases. Some new antibiotic combinations provide coverage against highly resistant isolates but are unable to target organisms that produce metallo-β-lactamases. Aztreonam in combination with avibactam provides a broad spectrum of activity against highly resistant isolates that also targets metallo-β-lactamase-producing organisms. An important part of drug development is the ability for clinical labs to determine the susceptibility of isolates to the antimicrobial. This manuscript investigates the in vitro susceptibility testing of aztreonam/avibactam with nonstandard testing conditions and a correlation study between broth microdilution and agar dilution against clinical isolates encoding a variety of resistance mechanisms. Overall, aztreonam/avibactam was generally unaffected by changes in testing conditions and showed strong agar/broth correlation.

Treatments and Predictors of Mortality for Carbapenem-Resistant Gram-Negative Bacilli Infections in Malaysia: A Retrospective Cohort Study

This study evaluated the treatments, mortality rate and patient-related factors associated with mortality. This is a retrospective study involving hospitalised patients with infections caused by carbapenem-resistant Gram-negative bacilli (CR-GNB) in a tertiary hospital in Malaysia from January 2018 to June 2020. A clinical pharmacist reviewed patients' electronic records and collected the data according to a pre-designed form. Data were analysed using both descriptive and inferential tests. The study included 145 patients with CR-GNB infections including 77, 40 and 28 Acinetobacter baumannii, enterobacteriaceae and Pseudomonas aeruginosa, respectively. The mean age was 57.9 ± 15.8 years. Pneumonia (40.7%) and bacteremia (25.5%) were the most common infections. Meropenem (24.7%) and piperacillin-tazobactam (20.4%) were the most commonly used empiric antibiotics while colistin (63.3%) and amikacin (8.3%) were the most common definitive antibiotics. The mean duration before active antibiotics was 4.6 ± 3.3 days. Overall, the in-hospital mortality rate was 41.4%. Multivariate logistic regression analysis showed that intensive care unit (ICU) admission (adjusted odds ratio (AOR): 5.201; 95% confidence interval (CI): 1.603-16.872; p = 0.006), sepsis/septic shock (AOR: 3.430; 95% CI: 1.021-11.522; p = 0.049) and elevated serum creatinine (AOR: 2.752; 95% CI: 1.005-7.536; p = 0.049) were independently associated with mortality. The mortality rate among patients with CR-GNB infection is high. A high rate of inappropriate antibiotic use was observed, including combination antibiotic therapy and delays in starting active antibiotics. Mortality was significantly associated with ICU admission, sepsis/septic shock and elevated serum creatinine.

How to use new antibiotics in the therapy of serious multidrug resistant Gram-negative infections?

PURPOSE OF REVIEW

Multidrug resistant Gram-negative infections are becoming more common and pose a serious threat to both individual patients and the population as a whole. Treatment of these infections can be difficult and result in significant morbidity and mortality. The purpose of this review is to discuss information and strategies for using new antibiotics to combat these infections.

RECENT FINDINGS

Eight new antibiotics represent possible means to treat multidrug resistant Gram-negative infections. Although no new mechanisms of action are present amongst these new antibiotics, novel additions to previously utilized mechanisms have been shown to be viable options for treatment of highly resistant organisms.

SUMMARY

The novel antibiotics considered in this review have varying data on their use as empiric treatment of patients at high risk for multidrug resistant organisms and as final therapy for identified multidrug resistant organisms. Cefiderocol, ceftazidime-avibactam, ceftolozane-tazobactam, meropenem-vaborbactam, and imipenem-relabactam have the best support evidence for use in this patient population.

Evaluation of ceftazidime/avibactam for treatment of carbapenemase-producing carbapenem-resistant Enterobacterales with OXA-48 and/or NDM genes with or without combination therapy

Background

Carbapenem-resistant Enterobacterales (CRE) is an urgent public health threat of significant global concern. Few observational studies have evaluated the clinical outcomes for treatment of CRE harbouring OXA-48 or NDM genes with ceftazidime/avibactam. Previous findings showed lower 30 day mortality with ceftazidime/avibactam ranges between 8.3% and 22%.

Method

This single-centre retrospective cohort study included adult patients aged ≥18 years admitted to King Abdulaziz Medical City (KAMC) who had received ceftazidime/avibactam for at least 72 h for infections caused by CRE with genes encoding for carbapenemase production (CP-CRE).

Results

A total of 211 patients, mostly male (57%), having CP-CRE infections treated with ceftazidime/avibactam were included, with an average age of 62 years. More than 50% of patients were critically ill, for which 46% received invasive ventilation and 36% were on inotropes. The most frequent infectious disease was hospital/ventilator-acquired pneumonia with Klebsiella pneumoniae being the most frequent causative pathogen. The majority of isolates harboured OXA-48 (81%), followed by NDM ± OXA-48 (19%). The overall clinical cure and 30 day mortality was 78% and 21% respectively (stratified per gene: 79% and 21.6% for OXA-48 and 75% and 17.5% for NDM ± OXA-48).

Conclusions

This was the largest study that evaluated clinical outcomes associate with CP-CRE harbouring OXA-48 gene infections treated with ceftazidime/avibactam. Clinical cure and 30 day mortality were consistent with those of previous studies. Findings suggested that combination therapy with ceftazidime/avibactam had no direct impact on clinical outcomes for CP-CRE with OXA-48.

Update of clinical application in ceftazidime-avibactam for multidrug-resistant Gram-negative bacteria infections

PURPOSE

Multidrug-resistant Gram-negative bacteria (MDR-GNB) have become a major global public health threat. Ceftazidime-avibactam (CAZ-AVI) is a newer combination of β-lactam/β-lactamase inhibitor, with activity against carbapenem-resistant Enterobacterales (CRE) and carbapenem-resistant Pseudomonas aeruginosa (CRPA). The aim of this review is to describe the recent real-world experience of CAZ-AVI for the infections due to MDR-GNB.

METHODS

We searched PubMed, Embase and Google Scholar for clinical application in CAZ-AVI for MDR-GNB infections. Reference lists were reviewed and synthesized for narrative review.

RESULTS

MDRGNB infections are associated with higher mortality significantly comparing to drug-susceptible bacterial infections. Fortunately, CAZ-AVI shows significant benefits for infections due to KPC or OXA-48 CRE, comparing to colistin, carbapenem, aminoglycoside and other older agents, even in those with immunocompromised status. The efficacy of CAZ-AVI varies in different infection sites due to CRE, which is lower in pneumonia. Early use is associated with improved clinical outcomes. Noteworthy, when adopted as salvage therapy, CAZ-AVI is still superior to other GNB active antibiotics. CAZ-AVI plus aztreonam is recommended as the first line of MBL-CRE infections. However, for infections caused by KPC- and OXA-48-producing isolates, further investigations are needed to demonstrate the benefit of combination therapy. Besides CRE, CAZ-AVI is also active to MDR-PA. However, the development of resistance in CRE and MDR-PA against CAZ-AVI is alarming, and more investigations and studies are needed to prevent, diagnose, and treat infections due to CAZ-AVI-resistant pathogens.

CONCLUSIONS

CAZ-AVI appears to be a valuable therapeutic option in MDR-GNB infections. Using CAZ-AVI appropriately to improve efficacy and decrease the emergence of resistance is important.

Treatment of ventilator-associated pneumonia due to carbapenem-resistant Gram-negative bacteria with novel agents: a contemporary, multidisciplinary ESGCIP perspective

INTRODUCTION

: In the past 15 years, treatment of VAP caused by carbapenem-resistant Gram-negative bacteria (CR-GNB) has represented an intricate challenge for clinicians.

AREAS COVERED

In this perspective article, we discuss the available clinical data about novel agents for the treatment of CR-GNB VAP, together with general PK/PD principles for the treatment of VAP, in the attempt to provide some suggestions for optimizing antimicrobial therapy of CR-GNB VAP in the daily clinical practice.

EXPERT OPINION

Recently, novel BL and BL/BLI combinations have become available that have shown potent in vitro activity against CR-GNB and have attracted much interest as novel, less toxic, and possibly more efficacious options for the treatment of CR-GNB VAP compared with previous standard of care. Besides randomized controlled trials, a good solution to enrich our knowledge on how to use these novel agents at best in the near future, while at the same time remaining adherent to current evidence-based guidelines, is to improve our collaboration to conduct larger multinational observational studies to collect sufficiently large populations treated in real life with those novel agents for which guidelines currently do not provide a recommendation (in favor or against) for certain causative organisms.