Acinetobacter blood stream infection in a teaching hospital- Riyadh, Saudi Arabia

To study the clinical conditions of patients with blood stream infection [BSI] due to Acinetobacter species, the predisposing factors, the antimicrobial susceptibilities and the outcome of infection by these organisms. Settings: The study took place at King Khalid University Hospital, Riyadh, Saudi Arabia. Forty patients with blood stream infection due to Acinetobacter species were prospectively studied. Acinetobacter isolates were identified by API 20E. Antimicrobial susceptibility to 13 antimicrobial agents was performed by a disc comparative Stoke's method. For 23 isolates, susceptibility was also tested by minimum inhibitory concentration using E test [Abbiodisk, Solna, Sweden]. The predominant Acinetobacter isolate was Acinetobacter baumannii 24 [60%] followed by Acinetobacter baumannii complex 10 [25%] and six [15%] were other Acinetobacter species. Patients with Acinetobacter baumannii blood stream infection were more frequently managed in intensive care units. Nineteen of them [47.5%] had serious underlying illnesses predisposing to Acinetobacter blood stream infections including, cardiac, renal diseases, prematurity and severe burns with six [25%] having a fatal outcome. Risk factors for Acinetobacter baumannii blood stream infection included: intravascular catheters, mechanical ventilation, prior antibiotic use and colonization at other body sites. These factors were independently associated with Acinetobacter baumannii acquisition in these patients [P = > 0.05]. The results of anti microbial susceptibility tested by disc diffusion method were comparable to those of E test. Among the 13 anti microbial agents tested, imipenem was the most active agent against Acinetobacter baumannii as well as other Acinetobacter species. We concluded that Acinetobacter baumannii is the most common Acinetobacter species causing significant blood stream infections among patients in intensive care units with serious underlying illnesses. Risk factors studied were independently associated with the disease process of these patients. Imipenem is the most active anti microbial agent against clinically significant Acinetobacter baumannii blood stream infection

Biotyping of Acinetobacter species isolated from clinical samples.

We used the biotyping scheme using carbohydrate substrate utilization test with 14 carbon sources to speciate Acinetobacter isolates from blood and cerebrospinal fluid cultures of patients admitted to the postoperative neurosurgery ICU during January to November 1996. Sixty one patients culture positive for Acinetobacter sp. from blood or cerebrospinal fluid were followed up prospectively. Among these patients, 40 patients had clinically diagnosed infections like bacteriemia or meningitis while in 21 patients the isolation was regarded as contaminants. A. baumanniii was the most common isolate associated with clinical infections while A. lwoffii was more likely to be an environmental contaminant.