Investigation of agents causing urinary tract infection using chromogenic agar medium

Aim: Clinical syndromes caused by urinary tract infections continue to have a serious impact worldwide, especially on female patients. Urinary tract infections (UTIs) constitute 20-50% of hospital-acquired infections occurring in the intensive care unit and are a significant cause of morbidity in geriatric patients. Patients receiving inpatient treatment in the intensive care unit are exposed to a significant number of hospital-acquired infections, and a significant majority of the microorganisms that cause infection in these patients develop high rates of multidrug resistance. In our study, we aimed to identify the pathogens that cause infection directly from the first plate by using chromogenic media in urine cultures taken from intensive care patients and, accordingly, to enable the appropriate empirical treatment to be started earlier. Materials and Methods: In this study, 600 urine samples from patients hospitalized in intensive care units, sent to Fırat University Hospital Central Laboratory/Microbiology Laboratory between April 2023 and September 2023 for routine culture, were examined both by conventional methods and on chromogenic agar medium (CHROMagar MH Orientation environment, France). Urine samples inoculated on 5% sheep blood Colombia agar, EMB (Eosin Methylene Blue) agar and CHROMagar MH Orientation medium were incubated in an aerobic environment at 35-37 °C for 18-24 hours. Pathogens were identified using traditional methods in the media where growth was detected at the end of incubation. Color pigmentations in CHROMagar medium were evaluated in accordance with the manufacturer's recommendations. Chi-square was used for statistical analysis of the data obtained in the study (p<0.05). Findings: In our study; 207 of 600 urine samples were evaluated as positive urine culture. Distribution according to the intensive care units where the patients were followed: 53.00% (n:318) Anesthesiology and Reanimation Intensive Care Unit, 37.00% (n:222) Internal Medicine Intensive Care Unit, 10% (n:60) were identified as other intensive care units. The most frequently isolated species from urine cultures is Candida spp. (n=145). Escherichia coli (E.coli) (n=21) was determined to be the most dominant species isolated among Gram-negative bacteria. Gram positive bacteria isolated from urine cultures are Enterococcus faecium (E.faecium) (n=4) and Enterococcus faecalis (E.faecalis) (n=1). It was observed that the pigmentation of the species detected in chromogenic agar was in accordance with the manufacturer's instructions. 5 urine samples, which were evaluated as contamination in blood agar and MacConkey agar, were found to grow pathogenic bacteria as pure cultures in their cultures on CHROMagar MH Orientation medium. In these cultures, Enterococcus spp. as pure culture. (E.faecium (n=3), E.faecalis (n=2)) grew. No contamination was detected in any of the growths on the CHROMagar MH Orientation medium. In 12 samples that were evaluated as showing no growth on conventional media, Candida spp. was detected as pure culture on CHROMagar MH Orientation media. (C.albicans (n=4)) and Enterococcus spp. (E.faecium (n=5), E.faecalis (n=3)) were grown. Conclusion: The general findings of our study revealed that CHROMagar supported the development of all uropathogens and enabled the rapid identification of organisms according to their color morphology and easy growth within 24 hours even in mixed bacterial culture. When we look at the distribution of urine culture positivity by gender, Chi-square analysis found that the reproductive positivity detected in the total urine culture in female gender was significant compared to the reproductive positivity detected in total male gender (p = 0.0003) (Table 4).In addition, it was concluded that the CHROMagar Orientation chromogenic media tested in urine cultures in our study are attractive and easy-to-use screening media that significantly reduce the daily workload and the number of identification kits required.