Causes of gram negative bacteremia and i̇ncreasing antibiotics resistance

Background. Albeit medical advances, bacteremia and sepsis risk increased recently. Causes of increased risk includes higher percent of elderly population, increased lifetime of patients with chronic diseases, widely used immunosuppressive drugs and increased usage of invasive methods for both diagnostic and therapeutic purposes. Furthermore, ever-increasing antibiotic resistance all over the world and limited source of antibiotics against resistant bacteria's present a challenge to the care givers. Objective. To make a contribution to our country's data base and to set a follow-up protocol by data acquisition of gram negative bacteremia findings of Ankara Başkent University, school of medicine. Purpose. For this purpose, we examined the distribution, frequency and the rate of antibiotic resistant of Escherichia coli, Klebsiella pneumoniae, Enterobacter spp., Pseudomonas aeruginosa, Acinetobacter baumanni that are common causes of gram negative bacteremia in last 12-year period. Materials and Method. In this retrospective study, we analyzed 3604 microbiological examen results of blood cultures of adult patients that were hospitalized and sent to Microbiology Laboratory at Başkent University school of medicine from medical follow-up and documentation system namely Nucleus and AviCenna programs for the 12-year period between January 2004 and December 2015. We did not discriminate hospital or community-based contaminations. The median age was 66,0. The mean age was 64.8±18.0 years and 50.5% (n=1819) of them were female and 49.5% (n=1819) of them were male. Results. We found that there was an increasing trend for resistant gram negative bacteremia incidence over years from 2004 (2.5%; n=90) to 2015 (15.3%; n=550). By frequency, the most common gram negative bacteria were E. coli, K. pneumoniae, P. aeruginosa, A. baumannii and Enterobacter spp. For 2015, the rates were as follows: E. coli (36,0%), K. pneumoniae (21,8%), P. aeruginosa (16,9%), A. baumannii (12,0%), Enterobacter spp (6,0%). We investigated K. pneumoniae and E. coli species for extended-spectrum beta-lactamase (ESBL) positivity and we found that the ESBL positivity was increased in the last three years. The rates of ESBL positive species were similar for E. coli and K. pneumoniae. Strikingly, there was an increased carbapenem resistance in the last three years against K. pneumoniae and P. aeruginosa. A. baumannii was resistant against all antibiotics at high rates. For 2015, the rates of antibiotic resistance were 72,7% for amikasin, 87,9% for imipenem, 87,9% for meropenem, 87,9% for levofloxacin, 87,9% for ciprofloxacin and 80,3% for trimethoprim-sulfamethoxazole. Conclusion. Swift inception of empiric antibiotic therapy, accurate antibiotic selection with appropriate duration of utilization are of great importance. Rational antibiotic management, development and usage of new antimicrobial drugs are of paramount importance for overcoming problems in treatment of gram negative bacteremia's. Keywords. Bacteremia; Gram negative; Resistance rates; Blood culture