Multi drug Drug resistant Acinetobacter baumannii –Challenges and New drugs for approval by Dr.T.V.Rao MD

Multi drug Drug resistant Acinetobacter baumannii –Challenges and New drugs for approval by Dr.T.V.Rao MD The genus Acinetobacter is a member of the family Moraxellaceae in the order Pseudomonadales More than25 species within the genus Acinetobacter have been described; however, member species in this genus are difficult to differentiate and only some have been officially named. The most important species of this genus in human pathology is Acinetobacter baumannii In the recent past we are isolating several non-fermenting Gram negative bacilli, many times we jump to conclusions as multidrug resistant Acinetobacter baumani, all may not be true when we do few battery of Biochemical tests The role of multidrug resistant Acinetobacter baumanii and its clinical relevance have been recently appreciated as a ubiquitous opportunistic nosocomial pathogen. Risk factors associated with A. baumanii infection include severe underlying diseases, previous surgery, invasive procedures, treatment with broad-spectrum antibiotics, length of hospital stay, admission to intensive care units (ICU). Carbapenem-multidrug resistant A. baumanii infections are probably associated to greater severity and more complications. However, severe underlying diseases probably play an important role in the clinical outcome of patients with MDR-C A. baumanii infection and controversy exists regarding the real mortality attributable to antimicrobial resistance because a high proportion of deaths took place > 7 days after diagnosis. The increase in the prevalence of A. baumannii resistance is worrying because of the diversity of the enzymes implicated in the resistance and its epidemic diffusion that is always difficult to handle. Certain strains of MDR Ab have been found to contain as many as 54 resistance genes, with 45 residing on a single “resistance island” alone and at any given time, the expression or relative quiescence of resistance genes is driven in part by antibiotic selection pressure To be familiar with what it means resistance, Defining MDR Acinetobacter baumannii (MDR Ab):A. baumannii with multidrug resistance to more than two of the following five drug classes: Antipseudomonal cephalosporins (ceftazidime or cefepime), Antipseudomonal carbapenems (imipenem or meropenem), and ampicillin/sulbactam, fluoroquinolones (ciprofloxacin or levofloxacin), and aminoglycosides (Gentamicin, tobramycin, or amikacin). A-Pan drug resistant Acinetobacter baumannii: A. baumannii with additional antimicrobial resistance in all drug classes, plus resistance to polymyxin and/or colistin (note- however there is no standardized definition of pan resistant Acinetobacter baumanni. I wish all the Younger Microbiologists to follow the Protocols given in Bailey and Scot diagnostic Microbiology (Current Edition) in identification of Acinetobacter baumannii as there are several changes in Taxonomy in identification of the bacteria, or else we will misinform the prevalence and incidence of A. baumanii infections, in our routine Diagnostic Microbiology Laboratories. Many laboratories are over reporting the incidence of isolation of Acinetobacter baumani in view of lack of facilities to do proper identification; however we should be cautious in reporting the multi resistance strains without quality controls, as clinician’s start using higher generation of antibiotics which is counterproductive with overzealous reports of Microbiologists? (An Observation)

Antimicrobial therapy

A.baumannii empirical coverage is recommended in severe infections occurring during an A. baumannii outbreak or in endemic situations or previously colonized patients Carbapenems are thought to be the drugs of choice for infections caused by A. baumannii in areas with low rates of resistance, but should not be used as monotherapy for severe infections in areas with high rates of resistance [33]. Although there is no consensus recommendation for the optimal treatment of MDR-AB infections, colistin is currently used as the backbone of therapy, despite its nephrotoxic effects It is suggested as part of empirical therapy in patients with high suspicion of/proven carbapenem resistant A. baumannii The efficacy of colistin in severe infections caused by A. baumannii has been demonstrated in several retrospective series or case reports . Due to colistin having low penetration into the pulmonary epithelial lining fluid with IV administration (due to its physiochemical properties), the use of inhaled colistin in conjunction with IV colistin is becoming increasingly popular as a way to reduce the nephrotoxic effects associated with high doses of IV colistin.

What is the new drug for carbapenem resistant Acinetobacter baumannii?

Carbapenem-resistant Acinetobacter baumannii (CRAB) is a perilous nosocomial pathogen causing substantial morbidity and mortality. Current treatment options for CRAB are limited and suffer from pharmacokinetic limitations, such as high toxicity and low plasma levels. As a result, CRAB is declared as the top priority pathogen by the World Health Organization for the investment in new drugs. This urgent need for new therapies, in combination with faster FDA approval process, accelerated new drug development and placed several drug candidates in the pipeline

Researchers have identified a new class of antibiotics with the potential to tackle a drug-resistant bacterium, Acinetobacter baumannii. Zosurabalpin was found to be effective against CRAB (carbapenem-resistant Acinetobacter baumannii)-induced pneumonia and sepsis in mouse models.await more human studies for Approval by FDA

Dr.T.V.Rao MD