Stable susceptibility to aminoglycosides in an age of low level, institutional use

Evaluating the resistance pattern of gram-negative bacteria during three years at the nephrology ward of a referral hospital in southwest of Iran

BACKGROUND

Gram-negative bacteria are associated with an increase in rates of antibacterial resistance. In most low- and middle-income countries such as Iran, there is no continuous surveillance system for antibiotic resistance.

OBJECTIVE

The purpose of this survey was to determine the pattern of antimicrobial sensitivity of gram-negative bacteria within 3 consecutive years at a nephrology ward of Nemazee hospital in Shiraz.

MATERIALS AND METHODS

During a 3-year period from 2013 to 2015 at the adult nephrology ward, bacteriological data of all biological samples of hospitalized patients in favor of gram-negative microorganisms were analyzed retrospectively. Antimicrobial susceptibility was performed by the Kirby-Bauer disc diffusion method.

RESULTS

The most common gram negative bacterium isolated from biological samples was Escherichia coli (43.9%). The highest (86.3%-94.1%) antibacterial resistance rate was associated with Acinetobacter spp. The most frequent resistance was seen with cephalosporins. In contrast to ceftriaxone, ciprofloxacin, and trimethoprim/sulfamethoxazole, nitrofurantoin and aminoglycosides remained their acceptable activity against E. coli. At least three-fourths (75%) of Acinetobacter spp. isolates was resistant to either aminoglycosides or imipenem. All (100%) isolated Acinetobacter spp. and Pseudomonas aeruginosa species were susceptible to colistin. The rate of Acinetobacter spp. and P. aeruginosa resistant to three or more drugs was 81.7% and 74.6%, respectively.

CONCLUSIONS

The resistant rate of gram negative pathogens to different tested antibacterial agents was considerably high and has increased during the recent three years in our center.

Impact of an Antimicrobial Stewardship Program on Antimicrobial Utilization, Bacterial Susceptibilities, and Financial Expenditures at an Academic Medical Center

Background: Antimicrobial stewardship programs (ASPs) have the potential to improve patient outcomes, decrease microbial resistance, increase patient safety, and decrease costs. However, to justify the costs involved with providing an ASP, it is necessary to assess its impact in achieving these outcomes on an ongoing basis. Objective: The purpose of this study was to characterize the overall impact of the ASP at an Academic medical center. Methods: Quasi-experimental, before and after stewardship program implementation, retrospective analyses of quarterly antimicrobial utilization, bacterial susceptibilities, and antibiotic acquisition costs were utilized. Results: Mean stewardship-focused antibiotic utilization was 510.3 defined daily doses (DDD) per 1,000 patient days for the pre-ASP period and 426.4 DDD per 1,000 patient days for the ASP period (16.4% decrease; p < .001). Significant changes in Pseudomonas aeruginosa susceptibility to tobramycin (8% increase; p = .006) and piperacillin-tazobactam (8% decrease; p = .024) were noted. Changes in susceptibility of Staphylococcus aureus to methicillin (7% increase, p = .012) were also observed. ASP-focused antibiotic expenditures decreased from $4,028,068 in fiscal year (FY) 2010 to $2,135,173 in FY2013 (p = .01). Conclusions: ASP initiatives were associated with an observed reduction in stewardship-focused antibiotic utilization. Significant changes in susceptibilities of some bacteria were noted but did not seem to consistently reflect antibiotic utilization changes. Significant decreases in antimicrobial expenditures were observed. Observed outcomes are temporally related to shifts in antimicrobial selection through the initiation of stewardship program-driven antibiotic policy changes. These outcomes have been used to justify and expand our stewardship program moving forward.