Safety considerations of current drug treatment strategies for nosocomial pneumonia

ESKAPE bacteria characterization reveals the presence of Acinetobacter baumannii and Pseudomonas aeruginosa outbreaks in COVID-19/VAP patients

INTRODUCTION

A decrease of detection of outbreaks by multidrug-resistant bacteria in critical areas has been reduced due to COVID-19 pandemic. Therefore, molecular epidemiological surveillance should be a primary tool to reveal associations not evident by classical epidemiology. The aim of this work was to demonstrate the presence of hidden outbreaks in the first wave of the COVID-19 pandemic and to associate their possible origin.

METHODS

A population of 96 COVID-19 patients was included in the study (April to June 2020) from Hospital Juárez de México. Genetic identification and antimicrobial susceptibility testing of VAP causative agents isolated from COVID-19 patients was performed. Resistance phenotypes were confirmed by PCR. Clonal association of isolates was performed by analysis of intergenic regions obtained. Finally, the association of clonal cases of VAP patients was performed by timelines.

RESULTS

ESKAPE and non-ESKAPE bacteria were identified as causative agents of VAP. ESKAPE bacteria were classified as MDR and XDR. Only A. baumannii and P. aeruginosa were identified as clonally distributed in 13 COVID-19/VAP patients. Time analysis showed that cross-transmission existed between patients and care areas.

CONCLUSIONS

Acinetobacter baumannii and Pseudomonas aeruginosa were involved in outbreaks non-detected in COVID-19/VAP patients in the first wave of COVID-19 pandemic.

Defining Clinical and Microbiological Nonresponse in Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is a severe complication of mechanical ventilation, with mortality reduced most effectively by adequate early antibiotic treatment. The clinical and microbiologic response can be assessed easily from 72 hours after starting antibiotic treatment. Evidence of nonresponse is based on several factors: (1) lack of clinical improvement, (2) radiographic progression, (3) an impaired Sequential Organ Failure Assessment (SOFA) score, (4) no improvement by days 3 to 5 on the Clinical Pulmonary Infection Score (CPIS), (5) no decreased in biomarkers on day 3, and (6) isolation of a new pathogen on day 3. Among the clinical markers of treatment failure, physicians should consider no improvement in the ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO₂/FiO₂), persistence of fever or hypothermia, persistence of purulent respiratory secretions, and new-onset septic shock or multiple-organ dysfunction syndrome. Microbiological isolation of a new pathogen on day 3 is also associated with higher mortality, but persistence of the original pathogen does not seem to be associated with a worse prognosis. The real impact of changes to treatment after diagnosing nonresponsive VAP is unknown. Physicians must evaluate whether treatments are adequate in terms of sensitivity, dose, and route. Pharmacokinetically and pharmacodynamically optimized doses are recommended in these patients. Clinical stabilization of comorbidities or underlying conditions may be of benefit.

Safety evaluation of current therapies for high-risk severely ill patients with carbapenem-resistant infections

INTRODUCTION

Infections due to carbapenem-resistant Gram-negative bacteria (CR-GNB) are increasingly frequent events, which are associated with a high mortality rate. Traditionally, combination regimens including high doses of "old antibiotics" such as polymyxins, tigecycline, and aminoglycosides have been used to treat these infections, but they were often associated with low efficacy and high excess of side effects and toxicity, especially nephrotoxicity. Along with the development of new compounds, the last decade has seen substantial improvements in the management of CR infections.

AREAS COVERED

In this review, we aimed to discuss the safety characteristics and tolerability of different new options for treatment of CR infections.

EXPERT OPINION

The availability of new drugs showing a potent in vitro activity against CR-GNB represents a unique opportunity to face the threat of resistance, while potentially reducing toxicity. A thorough understanding of the safety profile from clinical trials may guide the use of these new drugs in critically ill patients at high risk for the development of adverse events. Future data coming from real-life studies for drugs targeting CR infections are crucial to confirm the safety profile observed in pivotal trials.

Secretory System Components as Potential Prophylactic Targets for Bacterial Pathogens

Bacterial secretory systems are essential for virulence in human pathogens. The systems have become a target of alternative antibacterial strategies based on small molecules and antibodies. Strategies to use components of the systems to design prophylactics have been less publicized despite vaccines being the preferred solution to dealing with bacterial infections. In the current review, strategies to design vaccines against selected pathogens are presented and connected to the biology of the system. The examples are given for Y. pestis, S. enterica, B. anthracis, S. flexneri, and other human pathogens, and discussed in terms of effectiveness and long-term protection.

Transglutaminase Cross-Linked Gelatin-Alginate-Antibacterial Hydrogel as the Drug Delivery-Coatings for Implant-Related Infections

Implant-related infection may be catastrophic and result in poor functional outcome, chronic osteomyelitis, implant failure or even sepsis and death. Based on a transglutaminase (TGase) cross-linked/antibiotics-encapsulated gelatin-alginate hydrogel, the main aim of this study is to establish an effective antibiotic slow-release system. The second aim is to evaluate the efficacy of a hydrogel-encapsulated antibiotic-containing titanium pin in preventing implant-related infections in a rat model. The prepared gelatin/alginate/gentamicin or vancomycin hydrogel was covalently cross-linked with transglutaminase (TGase). Its drug release profile and cytotoxicity were determined and the Wistar rat animal model was performed to validate its efficacy by radiographic examination, Micro-CT (computed tomography) evaluation and histo-morphological analysis at 12 weeks after surgery. When gelatin and alginate were thoroughly mixed with TGase, both 0.5% and 1.0% TGase can effectively cross link the hydrogel; the release of antibiotic is slowed down with higher degree of TGase concentration (from 20 min to more than 120 h). In the animal study, antibiotic-impregnated hydrogel is effective in alleviating the implant-related infections. Relative to that of a positive control group, the experimental group (vancomycin treatment group) showed significant higher bone volume, more intact bony structure with only mild inflammatory cell infiltration. This newly designed hydrogel can effectively deliver antibiotics to reduce bacterial colonization and biofilm formation on the implant surface. The remaining challenges will be to confer different potent antibacterial medications with good biocompatibility and fulfill the safety, practical and economic criteria for future clinical translation.