Analyzing Patterns for Stool Culture Requests by Physicians to Improve Quality

Although international clinical guidelines generally recommend bacterial stool cultures for patients with acute diarrhea, stool cultures are frequently being requested by physicians regardless of the likelihood of a bacterial infection. This study was conducted to improve the practice of requesting stool cultures by analyzing patterns for stool culture requests by physicians. We retrospectively reviewed 235 stool cultures of patients who visited Gyeongsang National University Hospital from January to February 2017. We analyzed the period of time after which the stool culture was requested after admission, stool characteristics, wet smear, and concomitant tests performed. 38.7% of stool culture requests were made within 3 days of admission. Stool form analysis showed that 36.6% of stools were watery and loose, and 18.8% were firm. Furthermore, >20 leukocytes per high-power field were found only in 0.4% of the wet smears. Among the stool culture requests, 78.7% were prescribed Clostridium difficile culture or toxin tests at the same time. In addition, 13.6% were prescribed diarrhea-causing viral tests as well. Only stool cultures were requested in 10.2% of the cases. Physicians rarely ensure that the adequate criteria are met when requesting for stool cultures. It is necessary to decrease unnecessary diagnostic practices to maintain the quality of care by establishing reliable rejection criteria and the physicians have valid reasons for requesting stool cultures.

Rapid Detection of Group B Streptococcus Using ChromID STRB and PCR in the Pregnant Women / 대한임상미생물학회지

BACKGROUND: Group B Streptococcus (GBS) can be transmitted to neonates during delivery through the birth canal. As awareness of neonatal GBS infections is increasing, more rapid and efficient screening tests are required. The aim of this study was to evaluate the performance of ChromID STRB (bioMérieux, France) and PCR compared with the standard culture method. METHODS: Recto-vaginal swabs were collected from 775 pregnant women from April 2016 to March 2017. Cotton swab cultures were grown in LIM broth overnight and then subcultured onto blood agar plates and ChromID STRB. PCR was carried out to detect atr genes specific for GBS. RESULTS: The carrier rate of GBS was 5.9% (46/775). The sensitivity, specificity, positive predictive value, and negative predictive value were 83.8%, 99.3%, 86.1%, and 99.2%, respectively, for ChromID STRB and 89.2%, 99.6%, 91.7%, and 99.5%, respectively for PCR. Both ChromID STRB and PCR detected 6 more cases compared to the standard culture. CONCLUSION: Chromogenic agar, ChromID STRB, and PCR using the atr gene showed excellent performance to screen for GBS. To administer prophylactic antibiotics efficiently, either selective chromogenic agar or PCR could be used in addition to the standard culture.