lipid-a and Cross-Infection

Acinetobacter baumannii is an opportunistic pathogen associated with nosocomial and community infections of great clinical relevance. Its ability to rapidly develop resistance to antimicrobials, especially carbapenems, has re-boosted the prescription and use of polymyxins. However, the emergence of strains resistant to these antimicrobials is becoming a critical issue in several regions of the world because very few of currently available antibiotics are effective in these cases. This review summarizes the most up-to-date knowledge about chromosomally encoded and plasmid-mediated polymyxins resistance in A. baumannii. Different mechanisms are employed by A. baumannii to overcome the antibacterial effects of polymyxins. Modification of the outer membrane through phosphoethanolamine addition, loss of lipopolysaccharide, symmetric rupture, metabolic changes affecting osmoprotective amino acids, and overexpression of efflux pumps are involved in this process. Several genetic elements modulate these mechanisms, but only three of them have been described so far in A. baumannii clinical isolates such as mutations in pmrCAB, lpxACD, and lpsB. Elucidation of genotypic profiles and resistance mechanisms are necessary for control and fight against resistance to polymyxins in A. baumannii, thereby protecting this class for future treatment.

Topics: Acinetobacter baumannii; Acinetobacter Infections; Animals; Anti-Bacterial Agents; Bacterial Proteins; Chromosomes, Bacterial; Cross Infection; Drug Resistance, Multiple, Bacterial; Ethanolaminephosphotransferase; Humans; Lipid A; Lipopolysaccharides; Mice; Microbial Sensitivity Tests; Plasmids; Polymyxins; Public Health

Despite the use of modern broad spectrum antibiotics nosocomial infections are an unsolved problem, especially in the field of neonatal intensive care (preterm babies and newborns). In patients with septic shock human monoclonal antibodies in combination with appropriate antibiotics have proven effective and compatible for children older than one year. So far, there have been no reports in the literature on the application of such kind of antiendotoxin immunotherapy for pre-term babies and newborns. We describe the effectiveness of monoclonal antibodies in two newborns. Already 12 respectively 16 hours after application of the human monoclonal IgM antibodies (Centoxin) and appropriate antibiotics, the clinical condition of our patients stabilized. Consecutively further clinical symptoms improved rapidly.

Topics: Anti-Bacterial Agents; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antibody Specificity; Combined Modality Therapy; Cross Infection; Female; Hirschsprung Disease; Humans; Infant, Newborn; Infant, Premature, Diseases; Lipid A; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Pseudomonas Infections; Shock, Septic; Surgical Wound Infection

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Bacterial Infections; Cross Infection; Endotoxins; Humans; Immunization, Passive; Incidence; Lipid A; Shock, Septic