Novel Cephalosporins in Septic Subjects and Severe Infections: Present Findings and Future Perspective

Finding value in novel antibiotics: How can infectious diseases adopt incremental cost-effectiveness to improve new antibiotic utilization?

Research and development of innovative antimicrobials is paramount to addressing the antimicrobial resistance threat. Although antimicrobial discovery and development has increased, difficulties have emerged in the pharmaceutical industry after market approval. In this minireview, we summarize clinical trial data on recently approved antibiotics, calculate incremental cost-effectiveness ratio (ICER) values, and explore ways to adapt ICER calculations to the limitations of antimicrobial clinical trial design. We provide a systematic review and analysis of randomized, controlled studies of antibiotics approved from 2014 - 2022 and extracted the relevant clinical data. Adapted-ICER (aICER) calculations were conducted using the primary condition-specific outcome that was reported in each study (percent mortality or percent cure rate). The literature search identified 18 studies for the 8 total antibiotics which met inclusion criteria and contained data required for aICER calculation. aICER values ranged from -$17,374 to $4,966 per percent mortality and -$43,931 to $2,529 per percent cure rate. With regards to mortality, ceftolozane/tazobactam and imipenem/cilastatin/relebactam proved cost efficacious, with aICER values of $4,965 per percent mortality and $1,955 per percent mortality respectively. Finding value in novel antibiotic agents is imperative to further justifying their development, and aICER values are the most common method of determining value in healthcare. The current outcomes of clinical trials are difficult to translate to aICER, which most effectively use Quality-Adjusted Life Years (QALY) as the quality standard in other fields such as oncology. Future antimicrobial trials should consider introducing methods of assessing measures of health gain such as QALY to better translate the value of novel antimicrobials in healthcare.

Stenotrophomonas maltophilia Infections in Haematological Malignancies and Hematopoietic Stem Cell Transplantation: A Case Series including Cefiderocol-Based Regimens

Background and Objectives: Stenotrophomonas maltophilia is a ubiquitous, aerobic, Gram-negative bacillus causing increasing concern in patients affected by haematological malignancies. Materials and Methods: We report a case series from two centres in Northern Italy to describe the characteristics, outcome and microbiological response of S. maltophilia infections in patients with haematological malignancies and/or allogenic hematopoietic stem cell transplantation (aHSCT). Results: Ten patients were included. The median age was 67 years, and seven patients (70%) were males. The median Charlson Comorbidity Index was 6 (IQR: 4-8). The most frequent haematological comorbidities were acute myeloid leukaemia (AML; n = 3; 30%) and non-Hodgkin's lymphoma (n = 3; 30%). Three (30%) patients underwent aHSCT before infection, all for AML. All the patients had undergone a recent antibiotics course and had an indwelling central venous catheter before infection. The main clinical presentations were nosocomial pneumonia, with (2; 20%) or without (4; 40%) secondary bloodstream infection and CRBSI (3; 30%). Four patients were treated with cefiderocol in monotherapy or combinations therapy with cotrimoxazole. The rest of the patients were treated with cotrimoxazole or levofloxacin in monotherapy. Conclusions: Despite a high rate of clinical improvement (90%) after starting antimicrobial therapy, we faced high 30-day mortality (30%) and in-hospital mortality (50%) rates in a highly comorbid population.

An Overview of Cefiderocol's Therapeutic Potential and Underlying Resistance Mechanisms

Antimicrobial resistance continues to increase globally and treatment of difficult-to-treat (DTT) infections, mostly associated with carbapenem-resistant (CR) Pseudomonas aeruginosa, CR Acinetobacter baumannii, and CR- and third-generation-cephalosporins-resistant Enterobacterales remains a challenge for the clinician. The recent approval of cefiderocol has broaden the armamentarium for the treatment of patients with DTT infections. Cefiderocol is a siderophore cephalosporin that has shown excellent antibacterial activity, in part due to its innovative way of cell permeation. It is relatively stable compared to most commonly found carbapenamases. However, some resistant mechanisms to cefiderocol have already been identified and reduced susceptibility has developed during patient treatment, highlighting that the clinical use of cefiderocol must be rational. In this review, we summarize the current available treatments against the former resistant bacteria, and we revise and discuss the mechanism of action of cefiderocol, underlying the biological function of siderophores, the therapeutic potential of cefiderocol, and the mechanisms of resistance reported so far.

Bloodstream Infection and Gram-Negative Resistance: The Role for Newer Antibiotics

Gram-negative resistance remains a major challenge. Rates of in vitro resistance to commonly utilized antibiotics have skyrocketed over the last decade. Clinicians now encounter multidrug-resistant organisms routinely. Fortunately, newer agents, such as ceftazidime-avibactam, ceftolozone-tazobactam, meropenem-vaborbactam, and cefiderocol, have been developed and are now available for use against these pathogens. Clinical trials with these novel therapies have focused on multiple infection types ranging from complicated urinary tract infections to nosocomial pneumonia. Nonetheless, there remains little information about the efficacy of these drugs for bacteremia. To better appreciate the types and limitations of the evidence supporting the role for these unique molecules in bloodstream infection, one requires an appreciation of the initial clinical trials supporting the regulatory approval of these antibiotics. Furthermore, physicians must understand the subsequent case series and reports specifically focusing on outcomes for patients with bacteremia treated with these drugs. Despite the limitations of the data and reports relating to treatment for bacteremia with these antibiotics, each agent appears to be efficacious and can provide good outcomes in bloodstream infections due to resistant pathogens.

Occurrence, Phenotypic and Molecular Characteristics of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli in Healthy Turkeys in Northern Egypt

Poultry is one of the most important reservoirs for zoonotic multidrug-resistant pathogens. The indiscriminate use of antimicrobials in poultry production is a leading factor for development and dissemination of antimicrobial resistance. This study aimed to describe the prevalence and antimicrobial resistance of E. coli isolated from healthy turkey flocks of different ages in Nile delta region, Egypt. In the current investigation, 250 cloacal swabs were collected from 12 turkey farms in five governorates in the northern Egypt. Collected samples were cultivated on Brilliance^TM ESBL agar media supplemented with cefotaxime (100 mg/L). The E. coli isolates were identified using MALDI-TOF-MS and confirmed by a conventional PCR assay targeting 16S rRNA-DNA. The phenotypic antibiogram against 14 antimicrobial agents was determined using the broth micro-dilution method. DNA-microarray-based assay was applied for genotyping and determination of both, virulence and resistance-associated gene markers. Multiplex real-time PCR was additionally applied for all isolates for detection of the actual most relevant Carbapenemase genes. The phenotypic identification of colistin resistance was carried out using E-test. A total of 26 E. coli isolates were recovered from the cloacal samples. All isolates were defined as multidrug-resistant. Interestingly, two different E. coli strains were isolated from one sample. Both strains had different phenotypic and genotypic profiles. All isolates were phenotypically susceptible to imipenem, while resistant to penicillin, rifampicin, streptomycin, and erythromycin. None of the examined carbapenem resistance genes was detected among isolates. At least one beta-lactamase gene was identified in most of isolates, where blaTEM was the most commonly identified determinant (80.8%), in addition to blaCTX-M9 (23.1%), blaSHV (19.2%) and blaOXA-10 (15.4%). Genes associated with chloramphenicol resistance were floR (65.4%) and cmlA1 (46.2%). Tetracycline- and quinolone-resistance-associated genes tetA and qnrS were detected in (57.7%) and (50.0%) of isolates, respectively. The aminoglycoside resistance associated genes aadA1 (65.4%), aadA2 (53.8%), aphA (50.0%), strA (69.2%), and strB (65.4%), were detected among isolates. Macrolide resistance associated genes mph and mrx were also detected in (53.8%) and (34.6%). Moreover, colistin resistance associated gene mcr-9 was identified in one isolate (3.8%). The class 1 integron integrase intI1 (84.6%), transposase for the transposon tnpISEcp1 (34.6%) and OqxB -integral membrane and component of RND-type multidrug efflux pump oqxB (7.7%) were identified among the isolates. The existing high incidence of ESBL/colistin-producing E. coli identified in healthy turkeys is a major concern that demands prompt control; otherwise, such strains and their resistance determinants could be transmitted to other bacteria and, eventually, to people via the food chain.

Bacterial and Viral Infections in Liver Transplantation: New Insights from Clinical and Surgical Perspectives

End-stage liver disease patients undergoing liver transplantation are prone to develop numerous infectious complications because of immunosuppression, surgical interventions, and malnutrition. Infections in transplant recipients account for the main cause of mortality and morbidity with rates of up to 80%. The challenges faced in the early post-transplant period tend to be linked to transplant procedures and nosocomial infections commonly in bloodstream, surgical, and intra-abdominal sites. Viral infections represent an additional complication of immunosuppression; they can be donor-derived, reactivated from a latent virus, nosocomial or community-acquired. Bacterial and viral infections in solid organ transplantation are managed by prophylaxis, multi-drug resistant screening, risk assessment, vaccination, infection control and antimicrobial stewardship. The aim of this review was to discuss the epidemiology of bacterial and viral infections in liver transplants, infection control issues, as well as surgical frontiers of ex situ liver perfusion.

Antibacterial activities of plant leaf extracts against multi-antibiotic resistant Staphylococcus aureus associated with skin and soft tissue infections

Background

The antibacterial activities of aqueous leaf extracts of Moringa oleifera, Vernonia amygdalina, Azadirachta indica and Acalypha wilkesiana against multidrug resistance (MDR) Staphylococcus aureus associated with skin and soft tissue infections were investigated.

Methods

Staphylococcus aureus (n = 183) from the skin and soft tissue infections with evidence of purulent pus, effusions from aspirates, wounds, and otorrhea were biotyped, and evaluated for biofilm production. The phenotypic antibiotic resistance and MDR strains susceptibility to plant leaves extract were determined using disc diffusion and micro-broth dilution assays respectively. The correlation of plant extract bioactive components with inhibitory activities was determined.

Results

High occurrence rate of S. aureus were recorded among infant and adult age groups and 13.2% mild biofilm producers from the wound (p < 0.05). Of 60.2% MDR strains with overall significant MARI of more than 0.85 (p < 0.05), high resistant rates to linozidine (92.7%; 95% CI:7.27–10.52), ofloxacin (94.2%; 95% CI:6.09–8.15), chloramphenicol (91.2%; 95% CI:6.11–8.32), gentamicin (97.3%; 95% CI:6.20–8.22), ciprofloxacin (92.7%; 95% CI: 5.28–7.99) and vancomycin (86.6%; 95% CI:6.81–9.59) were observed. Vernonia amygdalina and Azadirachta indica showed significant antimicrobial activity at 100 mg/ml and 75 mg/ml, with low susceptibility of less than 10% to 25 mg/ml, 50 mg/ml, and 75 mg/ml Moringa oleifera. Alkaloids, saponin and terpenoids were significant in Moringa oleifera, Acalypha wilkesiana, Azadirachta indica and Vernonia amygdalina leaves extracts (p < 0.05). High inhibitory concentrations at IC50; 3.23, 3.75 and 4.80 mg/ml (p = 0.02, CI: − 0.08 – 11.52) and IC90; 12.9, 7.5, and 9.6 mg/ml (p = 0.028, CI: 2.72–23.38) were shown by Acalypha wilkesiana, Vernonia amygdalina and Moringa oleifera respectively. Comparative outcome of the plant extracts showed Acalypha wilkesiana, Vernonia amygdalina and Moringa oleifera to exhibit significant inhibition activities (p < 0.05) compared to other extracts. Significant median inhibitory concentration (15.3 mg/ml) of Azadirachta indica were observed (p < 0.01) and strong associations of phytochemical compounds of Azadirachta indica (eta = 0.527,p = 0.017), Vernonia amygdalina (eta = 0.123,p = 0.032) and Acalypha wilkesiana (eta = 0.492,p = 0.012) with their respective inhibitory values.

Conclusion

Observed high occurrence rate of skin and soft tissue infections caused by biofilm-producing MDR S. aureus requires alternative novel herbal formulations with rich bioactive compounds from Moringa oleifera, Acalypha wilkesiana, Azadirachta indica and Vernonia amygdalina as skin therapeutic agents.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03527-y.

Carbapenemase-Producing Klebsiella pneumoniae Colonization and Infection in Solid Organ Transplant Recipients: A Single-Center, Retrospective Study

Carbapenemase-KPC producing Klebsiella pneumoniae (CP-Kp) infection represents a serious threat to solid organ transplant (SOT). All patients admitted between 1 May 2011 and 31 August 2014 undergoing SOT were included in the retrospective study. The primary outcomes included a description of the association of enteric colonization and invasive infections by CP-Kp with one-year mortality. Secondary outcomes were the study of risk factors for colonization and invasive infections by CP-Kp. Results: A total of 5.4% (45/828) of SOT recipients had at least one positive rectal swab for CP-Kp, with most (88.9%) occurring after transplantation. 4.5% (35/828) of patients developed a CP-Kp-related invasive infection, with 68.6% (24/35) being previously colonized. The 1-year mortality was 31.1% in patients with enteric colonization with CP-Kp and, it was 51.4% among patients with CP-Kp-related invasive infections. At univariate analysis, colonization, invasive infections, sepsis, severe sepsis, and septic shock were significantly associated with 1-year mortality. At multivariate analysis, only invasive infections and the combination of sepsis, severe sepsis, or septic shock were significantly associated with 1-year mortality, whereas gastrointestinal colonization was significantly associated with survival. In this population, the 1-year mortality was significantly associated with invasive infections; otherwise, gastrointestinal colonization was not associated with increased 1-year mortality.