Patient Demographics and Characteristics of Infection with Carbapenem-Resistant <i>Acinetobacter baumannii</i> in a Teaching Hospital from the United States

Abstract

A characterization of the clinical demographic features of patients with infection caused Acinetobacter baumannii, and the antibiotyping of the isolates recovered from these patients was undertaken, with a special reference to carbapenemresistant variants, and their risk factors. This study was conducted retrospectively from January 2010 to March 2011 at a 616-bed tertiary care university hospital. Sixty-four patients were identified. Clinical and microbiological data were analyzed for risk factors and demographic features to derive relative risk and odds ratio. We identified 100 A. baumannii from 64 patients during 15 months period. Significant risk factors were working age (18 -60 years), male gender, hospital stay (>1 week but <1 month), prior hospitalization, in a progressive care nursing units, respiratory/mechanical ventilation, polymicrobial infections and prior antibiotic therapy. Methicillin-resistant staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Klebsiella pneumoniae were the significant co-infecting agents. The antibiogram demonstrated multidrug resistance in a majority of the isolates. Relative risk associated with ventilator, diabetes, and surgery was higher in repeat isolates than in first isolates and were multidrug resistant. Repeat isolates were more resistant that the first isolates to most anti-acinetobacter agents, but the overall crude mortality was not significant during this study period, and couldn't correlated to the choice of treatment. In conclusion, a resistance against all clinically used carbapenems, and colistin is rapidly increasing in repeat isolates of A. baumannii; leaves narrow therapeutic options to treat multidrug-resistant and pandrug-resistant A. baumannii infection. For the first time we report rising incidence of colistin resistance by 20 percent in repeat isolates, and is worrisome for healthcare centers. A combination therapy should be adopted to treat such infection to avoid the emergence of colistin-resistant phenotypes in the United States.

Risk factors for hospital infections caused by carbapanem-resistant Acinetobacter baumannii

“…The fact that mechanical ventilation was the only invasive medical procedure associated with HIs caused by CRAB in our study is not surprising, because other researchers reported the same findings [13,14]. This procedure is frequently used in patients with respiratory failure, poor gas exchange, or increased difficulty breathing.…”

Molecular Characterization of Carbapenem Resistant Acinetobacter baumannii in Cancer Patients

“…Similarly, Dash et al reported that the majority of A. baumannii infections were detected from inpatients (90.5%) with 75.9% of cases spending 7 or more days in the hospital (Dash et al, 2013). Vaze and his colleagues recorded that 71% of patients infected by A. baumannii were hospitalized for more than one week (Vaze et al, 2013). Sixty two percent of cases were subjected to surgical procedures one month prior to infection; pointing to the importance of invasive procedures to acquisition of infection.…”

“…This was previously documented as A. baumannii were isolated primarily from respiratory tract specimens (49%) (Vaze et al, 2013), and endotracheal secretions (33.3%) (Fattouh and Nasr El-din, 2014). In general, these opportunistic pathogens are more commonly isolated from high risk hospitalized patients subjected to invasive procedures.…”

“…The isolate was considered as MDR, if resistant to more than two classes of antimicrobials (≥ 3 classes) (Vaze et al, 2013). Carbapenem resistant Acinetobacter isolates were defined as non-susceptible or with diminished susceptibility to meropenem and/or imipenem in vitro (Kim et al, 2012).…”

A Rising Threat – Risk Factors and Outcomes Related to Infections With Acinetobacter Species

“…Advanced age is a risk factor for acquiring infection with Acinetobacter species which could be attributed to the poor immune defense mechanisms in the elderly age group and the presence of coexisting comorbidities and chronic diseases. Other studies on infections with Acinetobacter species also reported male preponderance and increased incidence in older group [6,13].…”