Determination of antibiotic susceptibility of bacteria by flow cytometric method

In this study, it was aimed to determine the antibiotic susceptibility of bacterial strains by using flow cytometry method by comparing them with current standardized methods. Eleven clinical isolates and 6 standard bacterial strains were included in the study. MIC values were determined by broth microdilution method (BMD), VITEK 2® automated system and flow cytometric method (FCM). FCM was performed with the Accuri C6 flow cytometer. For all strains except P. aeuruginosa ATCC 27853 [BMD-FCM:r = 0.557(p = 0.048); VITEK 2-FCM:r = 0.529(p = 0.063)], E. faecalis ATCC 29212 [BMD-FCM:r = 0.393(p = 0.295); BMD-VITEK 2:r = 0.393(p = 0.295)], and vancomycin-resistant E. faecium clinical isolate [BMD-FCM:r = 0.452(p = 0.063)] r values were in the range of 0.802-0.969 for BMD-FCM (p < 0.001), 0.655-0.941 for BMD-VITEK 2 (p < 0.005) and 0.667-0.953 for FCM-VITEK 2 (p < 0.005). Correlation values of antibiotic susceptibility test results between three methods for Gram-negative bacteria were found as follows; r = 0.927(p < 0.001) for BMD-FCM, r = 0.851(p < 0.001) for BMD-VITEK 2, r = 0.807(p < 0.001) for VITEK 2-FCM. Correlation values were found as follows for Gram positive bacteria; r = 0.848(p < 0.001) for BMD-FCM, r = 0.877(p < 0.001) for BMD-VITEK 2, r = 0.800(p < 0.001) for VITEK 2-FCM. When all bacteria included in the study were evaluated as a total; it was r = 0.911(p < 0.001) for BMD-FCM, r = 0.888(p < 0.001) for BMD-VITEK 2, r = 0.835(p < 0.001) for VITEK 2-FCM. The methicillin resistance of the clinical methicillin resistant S. aureus isolate could not be detected by FCM. It was determined that there was a high level of correlation between methods. FCM shortens the duration of antibiotic susceptibility tests by 12-14 h and gives results within the same day. However, it has not been standardized to be widely used in microbiology laboratories and experienced personnel are needed for its implementation.

Evaluation of antibiotic use among hospitalised patients in a paediatric department of a training hospital in Turkey

BACKGROUND

Antibiotics are widely used and inaccurate or inappropriate prescription of antibiotics causes a significant increase in the prevalence of multidrug-resistant bacterial infections among children. This research aimed to study antibiotic prescriptions in hospitalised paediatric patients and to determine the prevalence of inappropriate antimicrobial use and the main types of prescribing errors.

METHODS

After obtaining the Ethics Committee approval, screening was conducted among 535 patients admitted to the Department of Pediatrics at Haydarpasa Numune Training and Research Hospital in the period from 01 January 2016 to 31 December 2016 who had been treated with an antibiotic. Patients' demographics, diagnosis and antibiotic therapy details were collected using a standardised case report form and assessed by a clinical pharmacologist and an infectious disease specialist regarding the convenience and accurateness of prescription of antibiotics.

RESULTS

Out of 535 antibiotic prescriptions, single antibiotics were used inappropriately in 216 (56.10%) of the patients and there were 39 (26%) unnecessary antibiotic combinations. Most of the errors were made in the dose frequency (55.69%), followed by indication (25.88%), administration route (16.08%) and dosage (2.67%).

CONCLUSIONS

The results of our study show that a high level of antibiotics in the paediatric clinic was misprescribed. Inappropriate usage increases the chances of microbial resistance and the cost of treatment. Precautions should be taken in this regard.