Japanese Society for Infection Prevention and Control-Online Journal

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Article in Japanese

Bacteriological Test Flow and How to Read the Results

Keita TATSUNO
Department of Infection Control and Prevention, Mitsui Memorial Hospital

Bacteriological tests are reported in different ways over time: In the initial stage, only the smear test results are reported; the next day or later, the identification or intermediate test results are reported; and the next day or later, the final results, including drug susceptibility test results, are reported. Nevertheless, empirical antimicrobial therapy or transmission-based precautions may be necessary even before the final results are available, depending on the severity of the patient and the urgency of the disease.
In the initial stage, it will be discussed about the morphology of the microorganisms seen on the smear test, and how they can be reflected in the treatments and precautions. Next, in the mid-term stage, we will mention that the identification and susceptibility results can be determined to some extent based on the characteristics of the isolated colonies or the growth conditions in blood culture and explain that in some cases, the treatments and precautions should be changed. After explaining the final result of susceptibility testing, we will examine this testing process by adapting the example of healthcare-associated infections seen in intensive care units.
When many medical devices are utilized, determining ventilator-associated pneumonia, catheter-related bloodstream infection, catheter-associated urinary tract infection, and so forth is often difficult. This does not mean that all of them should be treated with antimicrobial agents. Some of them should be treated as offending bacteria, whereas others should not be treated as colonization. The question to consider is the likelihood of infection and the thresholds for treatment and testing. We will learn how to approach these issues by utilizing the flow of bacteriological tests.

Key words：smear test, identification test, drug susceptibility test, severity, de-escalation

e-mail: tatsuno-tky＠umin.ac.jp

Received: February 16, 2023
Accepted: March 25, 2023

38 (4)：149─154,2023