Abstract
Background: Nosocomial infections due to high mortality and economic cost are one of the most important challenges that hospitals
face with it. Reports show that hospital acquired pneumonia (HAP) is the second most common nosocomial infection in some
countries such as the United States.
Objectives: The aim was to study the frequency and resistance pattern of Acinetobacter baumannii isolates against imipenem.
Methods: This cross-sectional study was conducted for 2 years on patients with nosocomial pneumonia caused by A. baumannii in
2 major university hospitals in Mashhad, Iran. After detection and identification, data regarding mortality, length of hospital stay,
and treatment were collected. Furthermore, the pattern of antibiotic resistance was investigated in A. baumannii against imipenem.
Results: In this study, among 700 patients with nosocomial pneumonia, 364 and 336 of those were male and female, respectively.
All of these received imipenem. Of the total patients, 317 cases (45%) were resistant to imipenem. 84% of these patients were cured
and the remaining 16% expired (P value = 0.001). A. baumannii resistance to the imipenem in both hospitals had an increasing rate.
The resistance rate in the Ghaem hospital increased 96.6% at the end of the period compared to beginning of study (P value = 0.004).
Also, a similar increase (94.7%) was observed in the Imam Reza hospital (P value = 0.003).
Conclusions: According to our results, excessive use of imipenem has been caused by antibiotic resistance, for this, the appropriate
selective choice of antibiotics should be considered. At first, other antibiotics such as new generations of cephalosporins should be
chosen for empirical treatment of A. baumannii.