Background and objective: Implementation of standard methods for accurate detection of bacteria, correct antibiotic susceptibility testing and effective treatment of bacterial infections play important roles in development of public health and prevention of drug resistance. This study aimed to detect bacteria using standard methods and compare the results with the results obtained in teaching hospitals’ laboratories.

Methods: Positive culture plates containing bacteria isolated from patients in hospital laboratories in city of Sari were transferred to microbiology laboratory of Faculty of Medicine at Mazandaran University of Medical Sciences, after determining the genus and species of bacteria and antibiotic susceptibility testing of the isolates. The samples were re-examined based on standard protocols, and antibiotic susceptibility testing was done using the Kirby-Bauer method.

Results: Of 101 patients, 20% of bacteria and 22.5% of antibiotic sensitivity results reported by the hospital laboratories were incorrect. There were significant differences between the two study groups in terms of bacterial species detection and sensitivity to some drugs (P<0.05).

Conclusion: In the present study, lack of implementation of internal quality control programs in some hospital laboratories and lack of proper monitoring by regulatory authorities in different departments of the hospital have caused 20% false-detection results in hospital reports. Inconsistency in results of laboratories, false antibiograms and subsequent false laboratory reports cause drug resistance in some patients. This indicates the necessity of continuous training in the field of Microbiology and implementation of standard protocols and methods for detection of bacterial species and antibiotic susceptibility testing.