Acinetobacter baumannii strains isolated from patients in intensive care units in Goiânia, Brazil: Molecular and drug susceptibility profiles

Abstract

Resistance to antimicrobial agents is increasing worldwide and imposes significant life-threatening risks to several different populations, especially those in intensive care units (ICUs). Bacteria can quickly develop or acquire resistance to antimicrobial drugs, and combined with their intrinsic potential to cause disease in humans, these bacteria can become deadly. Among Gram-negative bacteria, Acinetobacter baumannii is notorious as a frequent opportunistic pathogen associated with critically ill patients, and understanding the genetic basis of A. baumannii resistance to beta-lactams among patients in ICUs will result in better protocols to prevent the development of resistance as well as improved treatment regimens. In this study, we assessed 1333 patients in five ICUs, 56 of whom developed A. baumannii infections. Most of the A. baumannii isolates were resistant to beta-lactam antimicrobial drugs, specifically, 3rd- and 4th-generation cephalosporins and carbapenems, and 91.1% of the isolates were multi-drug resistant (MDR). The most frequent OXA gene present was OXA-23 (55.1%), which is significantly associated with MDR strains. Most of the A. baumannii isolates (76.8%) were capable of forming a biofilm. The antimicrobial drug classes that were effective against most of these isolates were polymyxins and tigecycline. The molecular profile of the isolates allowed detection of 12 different clusters comprising 2 to 8 isolates each. In conclusion, our data indicate a high incidence of resistance to carbapenems as well as MDR strains among the observed A. baumannii isolates, most of which exhibited a high prevalence of OXA-23 gene expression. Only a few selective drugs were effective, reinforcing the notion that bacterial resistance is an emerging problem that should be prioritized in every healthcare facility.

Molecular typing of multi-drug resistant Acinetobacter baumannii isolates from clinical and environmental specimens in three Iranian hospitals by pulsed field gel electrophoresis

“…baumannii formed biofilm, which is in agreement with previous studies [2,17,22]. According to our results, 44.9% of isolates showed strong ability to biofilm formation.…”

“…This issue may indicate the possible transfer of related isolates from one ICU to another in the same hospital or different hospitals from patients admitted to the ICUs or the hospital health team in the same city. This type of transmission has been reported in several countries [2,29]. Comparing the frequency of biofilm formation ability in clinical and environmental isolates with pulsotypes, no significant correlation was found, which is consistent with the study of Wroblewska et al [30].…”

“…Acinetobacter baumannii is a gram-negative bacterium and one of the important pathogens of nosocomial infections, including pneumonia, meningitis, bacteremia, urinary tract infections, surgical wounds and soft tissue infections [1]. It has a key role in worldwide nosocomial infections, especially in the adult intensive care units (ICUs) [2,3]. Due to numerous factors, including prolonged hospital admission, loss of the skin barrier, and complex treatment protocols, patients admitted to ICU wards are significantly susceptible to nosocomial infections [4].…”

“…Recently, due to the use of broad-spectrum antibiotics, antimicrobial resistance between A. baumannii isolates has increased significantly. Therefore, the emergence of multi-drug resistant (MDR) and extensively drugresistant (XDR) A. baumannii isolates as an important cause of nosocomial infections is one of the major health problems in different countries of the world [2,5,6]. The impervious outer membrane and environmental exposure to a large pool of resistance genes are considered as selective pressures that cause XDR isolates in these bacteria [7].…”

Inhibition of <i>Acinetobacter baumannii</i> Biofilm Formation by Methanolic Extract of <i>Nothoscordum bivalve</i>

“…Various strains of A. baumannii have been isolated and identified in hospital environments worldwide in recent years, causing concern about its high resistance to antibiotics and hostile environments [33] [34]; its prevalence in Mexico has been reported in the last decade showing it as one of the main causal agents of nosocomial infections [3]. Due to the aforementioned circumstances, alternatives of natural origin are sought for their control and/or eradication.…”