Karyne Rangel

By Karyne Rangel and Salvatore Giovanni De-Simone

Antibiotic poly-resistance (multi drug-, extreme-, and pan-drug resistance) is a major global threat to public health. Unfortunately, in 2017, the World Health Organization (WHO) introduced the carbapenemresistant isolates in the priority pathogens list for which new effective antibiotics or new ways of treating the infections caused by them are urgently needed. Acinetobacter baumannii is one of the most critical ESKAPE pathogens for which the treatment of resistant isolates have caused severe problems; its clinically significant features include resistance to UV light, drying, disinfectants, and antibiotics. Among the various suggested options, one of the antimicrobial agents with high potential to produce new anti-Acinetobacter drugs is the antimicrobial peptides (AMPs). AMPs are naturally produced by living organisms and protect the host against pathogens as a part of innate immunity. The main mechanisms action of AMPs are the ability to cause cell membrane and cell wall damage, the inhibition of protein synthesis, nucleic acids, and the induction of apoptosis and necrosis. AMPs would be likely among the main anti-A. baumannii drugs in the post-antibiotic era. Also, the application of computer science to increase anti-A. baumannii activity and reduce toxicity is also being developed.

Part of the book: Insights on Antimicrobial Peptides

By Karyne Rangel, Thiago Pavoni Gomes Chagas and Salvatore Giovanni De-Simone

Nosocomial infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB) have become a global concern. The extensive antibiotic resistance of CRAB has significantly limited treatment options, while its prevalence in hospital outbreaks has amplified infection rates. This scenario has led to a resurgence of interest in polymyxins, an older class of antibiotics previously overlooked due to perceived toxicity. Polymyxins, cationic polypeptide antibiotics, now represent a last-resort treatment option. Despite their historical use, modern assessment methods have only recently been applied to evaluate polymyxins. Two polymyxins are available for clinical use: polymyxin B and colistin (polymyxin E). Notably, the administration of these drugs is hindered by toxicities, primarily nephrotoxicity and neurotoxicity, alongside less common adverse effects such as injection pain, hypersensitivity reactions, and bronchospasms.

Part of the book: Acinetobacter baumannii

By Thiago Pavoni Gomes Chagas, Karyne Rangel and Salvatore Giovanni De-Simone

Acinetobacter baumannii is an important bacterial pathogen associated with healthcare-associated infections (HAIs), especially in critically ill patients admitted to Intensive Care Units (ICU). Its ability to acquire antibiotic resistance determinants has propelled its clinical relevance. The rise in Acinetobacter infections and hospital outbreaks have been extensively described worldwide and are usually caused by carbapenem-resistant isolates. To compound the problem, Carbapenem-resistant A. baumannii (CRAb) isolates are also resistant to a wide range of other antibiotics, representing a serious threat to public health. Since 2017, A. baumannii has been listed as a critical priority pathogen that poses a great threat to human health, according to the World Health Organization (WHO). The carbapenem-resistant rates in A. baumannii are notorious around the world. However, Latin America has one of the highest in the world. Carbapenem resistance in A. baumannii is due mainly to the presence of horizontally acquired OXA-type carbapenem resistance genes, including bla_OXA-23, in most regions. Thus, this review aims to summarize the distribution of CRAb and its major carbapenem resistance mechanisms in Latin America.

Part of the book: Acinetobacter baumannii