The first report of identification of clinical isolates of Alcaligenes xylosoxidans and Alcaligenes faecalis by phenotypic and genetic methods in Iran

Background and Aim : Alcaligenes is a non-fermentative Gram-negative bacillus which as an opportunistic pathogen causes nosocomial infections, including urinary tract infections, pneumonia, and sepsis, and may be confused with Pseudomonas species. Diagnosis of Alcaligenes infections in hospital medical diagnostic laboratories is usually done by phenotypic methods and biochemical tests. However, due to possible errors and similarities with Pseudomonas, accurate diagnosis with phenotypic tests is not sufficient, and molecular methods for accurately identifying are more effective.Methods : In a six months descriptive-analytical study, we analyzed all ۳۶ isolates collected from hospitalized patients which were phenotypically identified as Alcaligenes. Using the PCR method and tracking AX and ۷۷F-r genes, we identified A. xylosoxidans and A. faecalis respectively, and the antibiotic resistance of each isolate was distinguished by the disc diffusion method.Results : Of ۳۶ samples of Alcaligenes identified by phenotypic methods and biochemical tests, only ۱۳ (۳۶.۱۱%) were A. xylosoxidans and ۳ (۸.۳۳%) were A. faecalis. among A. xylosoxidans the highest susceptibility (۹۲.۳%) was seen to Cephalosporin and the highest resistance (۷۶.۹۲%) was seen against Ciprofloxacin. Among A. faecalis isolates the most susceptibility (۱۰۰%) was seen to Ceftazidime, Piperacillin/Tazobactam, Imipenem, Meropenem, and Cefepime and the most resistance (۶۶.۶۶%) was against Gentamicin and Ceftriaxone.Conclusion : Since Alcaligenes species are a known cause of nosocomial infections with increasing prevalence in recent years, it seems that with phenotypic methods and biochemical tests, there is a possibility of error in their diagnosis, so using the PCR method, each species can be determined more accurately.

کلیدواژه ها:

Alcaligenes ، A. xylosoxidans ، A. faecalis ، molecular detection ، PCR method