Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology

6

Weeks in Review

2

Weeks to Publication
Indexed in KCI, KoreaMed, Synapse, DOAJ
Open Access, Peer Reviewed
pISSN 2288-0585 eISSN 2288-6850
Volume 27 │ Issue 2 │ June 2024
Special Issue on Current Epidemiology and Diagnostics of Parasitic Infections in Korea
Editorial

Challenging diagnosis of parasitic infection and practical guidance to clinical microbiology laboratories in Korea

Eun Jeong Won

Ann Clin Microbiol 2024 June, 27(2):39-40. Published on 20 June 2024.

(This article belongs to the Special Issue on Current Epidemiology and Diagnostics of Parasitic Infections in Korea)

Original article

Intestinal helminth infections among health examinees: 10-year (2011–2020) nationwide observations in Korea

Hyejoo Shin, Sooji Hong, Yoon-Hee Lee, Young-Sung Kim, Yoon-Joong Joo, Eun-Hee Lee, In-One Kim, Jong-Yil Chai, Bong-Kwang Jung

Ann Clin Microbiol 2024 June, 27(2):41-48. Published on 20 June 2024.

(This article belongs to the Special Issue on Current Epidemiology and Diagnostics of Parasitic Infections in Korea)

Background: A nationwide anti-parasite control program (1969–1995) successfully reduced soil-transmitted helminth infections; however, fish-borne trematode infections persisted in some areas. Since the 2012 National Parasite Infection Survey, information on the current status of intestinal helminth infections has not been updated. Analysis of the current trends in intestinal helminth infections is necessary to prevent and manage parasitic diseases in Korea.

Methods: This retrospective study analyzed the prevalence of intestinal parasites in 1,211,799 individuals who visited 16 regional branches of the Korea Association of Health Promotion between 2011 and 2020. Examinations were performed using microscopy and Kato’s method. The results were analyzed according to parasite species, year, sex, age, and region of origin.

Results: Intestinal helminth infections remained above 2.0% from 2011 to 2014 but decreased to 1.0% by 2020. Clonorchis sinensis had the highest infection rate (1.3%), followed by Metagonimus yokogawai (0.3%) and Trichuris trichiura (0.2%). Men had a higher infection rate (2.4%) than that of women (1.2%). The infection rate was higher among those in their 50s (2.0%), 60s, and older (1.8%). The highest regional infection rates were observed in Gyeongnam (4.8%), Ulsan (3.1%), Gyeongbuk (2.5%), Busan (1.8%), and Jeonnam (1.6%).

Conclusion: These results provide valuable insights into the decreasing prevalence and epidemiological characteristics of intestinal helminth infections in the Korean population. Therefore, various control measures are needed to prevent intestinal helminth infections, and continuous monitoring is essential until they are eradicated.

Review article

Practical guide for the diagnosis of helminth ova in stools

Woon-Mok Sohn, Jong-Yil Chai

Ann Clin Microbiol 2024 June, 27(2):49-67. Published on 20 June 2024.

(This article belongs to the Special Issue on Current Epidemiology and Diagnostics of Parasitic Infections in Korea)

In the age of globalization of infectious diseases, qualified personnel is needed for the diagnosis of parasitic diseases in the laboratory. This review aimed to introduce the methods for stool examination and identification of helminth eggs for the diagnosis of helminthic infections in laboratory and field surveys. The formalin-ether sedimentation technique (FEST) and the Kato-Katz egg counting technique (KKECT) are mainly described as representative stool examinations. The FEST is somewhat complicated and troublesome, but it is useful for differentiating small trematode eggs from opisthorchiid and heterophyid flukes. KKECT is useful in field surveys of large populations in areas endemic for soil-transmitted helminthiases. Helminth eggs are divided into four groups based on the presence or absence of the operculum and embryo. The eggs of Clonorchis sinensis and heterophyid flukes including Metagonimus spp. are relatively small and contain an operculum and an embryo (miracidium). Meanwhile, eggs of diphyllobothriid tapeworms, echinostomatid flukes, Paragonimus westermaniFasciola hepatica, and Fasciolopsis buski are relatively larger, operculated, and contain germ cells and yolks instead of the embryo. The eggs of cyclophyllidian tapeworms, Taenia spp. and Hymenolepis spp., and blood flukes, Schistosoma spp., are embryonated but do not have an operculum. Nematode eggs have no operculum and embryo, but those of hookworms and pinworms sometimes have developed larvae inside. This review provides valuable insights into the methods of stool examination and helminth egg identification for the diagnosis of helminthic infections in the laboratory and field surveys.

Review article

Molecular diagnosis of parasitic diseases in Korea

Sun Huh

Ann Clin Microbiol 2024 June, 27(2):69-79. Published on 20 June 2024.

(This article belongs to the Special Issue on Current Epidemiology and Diagnostics of Parasitic Infections in Korea)

The aim of this review is to provide practical guidance for the molecular diagnosis of parasitic diseases in Korea in 2024. Specifically, the prevalence of parasitic diseases, commercially available molecular diagnostic kits, and reference laboratories for molecular diagnosis are presented. It is based on the literature and the medical diagnosis device database of the Korea Disease Control and Prevention Agency. In Korea, molecular diagnostic kits are available for intestinal protozoa (Giardia lambliaEntamoeba histolyticaCryptosporidium hominis, and Cryptosporidium parvum), Trichomonas vaginalis, and malarial parasites. Molecular diagnosis of other parasites is also possible; however, there is no commercially available kit. Therefore, parasite samples or derivatives for molecular diagnosis should be sent to specific laboratories, the parasitology departments of medical schools, or the Division of Vectors and Parasitic Diseases, Bureau of Infectious Disease Diagnosis Control at the Korea Disease Control and Prevention Agency. In commercial diagnostic kits, multiplex real-time polymerase chain reaction (PCR) is used to rapidly and easily detect the amplified parasitic DNA. The loop-mediated isothermal amplification (LAMP) was developed to diagnose T. vaginalis and Acanthamoeba infections. Its merits are that it does not require a PCR machine and has a short test time of approximately 60 min. Although LAMP is not commercially available, it may be widely used to screen for parasitic diseases. Commercial molecular diagnostic kits for parasitic diseases are limited to the clinical setting in Korea. Available kits are used to diagnose certain intestinal protozoa, T. vaginalis, and to differentiate Plasmodium species using multiplex PCR.

Review article

Serological diagnosis of tissue-invading parasites in Korea

Min-Ho Choi

Ann Clin Microbiol 2024 June, 27(2):81-91. Published on 20 June 2024.

(This article belongs to the Special Issue on Current Epidemiology and Diagnostics of Parasitic Infections in Korea)

Although intestinal parasites are no longer considered a significant public health concern in Korea, tissue-invading parasites continue to pose clinical challenges. The diagnosis of tissue helminthiasis by recovering worms or larvae from tissues is invasive; therefore, serodiagnosis is widely used to diagnose infections caused by tissue-invading parasites. Among the serological tests, the enzyme-linked immunosorbent assay (ELISA) is the most commonly used, and various antigens, including crude antigens, excretory-secretory antigens of helminths, and cystic fluid of larval tapeworms, are used to detect specific IgGs against parasite antigens in the sera or cerebrospinal fluid of patients. A multi-antigen ELISA was used to diagnose four major tissue parasitic infections: clonorchiasis, paragonimiasis, cysticercosis, and sparganosis. In addition to these four parasitic infections, ELISA remains a valuable diagnostic method for toxocariasis, trichinellosis, fascioliasis, echinococcosis, and other diseases. A comprehensive history of the mode of transmission of the suspected parasites and the patient’s residence in or travel to an endemic area may help in making a definitive diagnosis. For the management of patients with eosinophilia in Korea, it is essential to perform ELISA for the differential diagnosis of toxocariasis. Serological tests have the disadvantage of being unable to differentiate between past and current infections, and the possibility of cross-reactivity requires careful interpretation. It is important to note that the results of serological tests are not necessarily conclusive and should be interpreted in the context of other symptoms, as well as clinical and imaging findings.

Review article

Anisakidosis in humans and animals and detection of anisakid larvae in fish and cephalopods in Korea: a literature review (1971-2022)

Jong-Yil Chai, Woon-Mok Sohn, Bong-Kwang Jung

Ann Clin Microbiol 2024 June, 27(2):93-130. Published on 20 June 2024.

(This article belongs to the Special Issue on Current Epidemiology and Diagnostics of Parasitic Infections in Korea)

Human anisakiasis (or anisakidosis) is a disease caused by the ingestion of marine fish or cephalopods infected with anisakid nematode larvae of the genera Anisakis, Pseudoterranova, Contracaecum, and Hysterothylacium. Anisakiasis is a clinically important disease that often manifests as an acute abdominal syndrome requiring emergency medical attention and care. In Korea, at least several thousand clinical cases have been diagnosed to date; however, only a small proportion of them have been reported in the literature (1971-2022). The most common etiological agents were Anisakis pegreffii (reported as Anisakis sp., Anisakis type I, or erroneously Anisakis simplex), followed by Pseudoterranova decipiens, Contracaecum sp., and Anisakis simplex sensu stricto (s.s.). Most cases involved the stomach and small or large intestine, with a few involving the oral cavity (oral mucosa, pharynx, and tonsils), esophagus, omentum, and mesocolic lymph nodes. Anisakis allergies and host immune responses have been studied in humans and experimental animals. Marine fish and cephalopods, including sea eel (Astroconger myriaster), squid (Todarodes pacificus), yellow corvina (Pseudosciaena manchurica), Japanese flounder (Paralichthys olivaceus), codfish (Gadus macrocephalus), yellowtail (Seriola quinquaradiata), and rockfish (Sebastes spp.), are the most common infection sources. Surveys were performed on anisakid nematode larvae in marine fish and cephalopods caught in the western, eastern, and southern seas of Korea. The larvae recovered from fish or cephalopods caught from the western and southern seas were predominantly A. pegreffii larvae; however, the larvae from the eastern sea were either A. pegreffii larvae (in the chub mackerel, Japanese flounder, and rockfish) or A. simplex s.s. (in the salmon and pollock; these fish migrate through the northern North Pacific Ocean and Bering Sea and come to Korea). Health education to avoid eating raw or improperly cooked marine fish and cephalopods (particularly the viscera) is crucial for preventing human anisakidosis in Korea.

Review article

Dengue fever: epidemiology, clinical manifestations, diagnosis, and therapeutic strategies

Teddy Namirimu, Sunjoo Kim

Ann Clin Microbiol 2024 June, 27(2):131-141. Published on 20 June 2024.

Dengue, a mosquito-borne viral infection, is rapidly increasing worldwide and affects over half of the world’s population in at-risk areas. Factors such as globalization, urbanization, and climate change have fueled its rapid geographical expansion. Although no indigenous dengue cases have been identified in Korea, the number of imported dengue cases has increased from travel to endemic regions. In Korea, dengue diagnosis relies mainly on detecting anti-dengue antibodies or viral nucleic acids using real-time polymerase chain reaction. Although specific antiviral treatments for dengue are currently unavailable, promising progress has been made in developing antiviral agents that target viral replication. Single-dose tetravalent live-attenuated dengue vaccine candidates are currently being evaluated for their safety and efficacy. Innovative vector control methods, including Wolbachia-infected and genetically modified species of Aedes mosquitos, have demonstrated promising results. Owing to the limited therapeutic options, vector control strategies remain a primary focus for preventing transmission, alongside ongoing research on antiviral drugs and vaccine development. This review provides insight into dengue fever transmission, clinical manifestations, and diagnosis. Additionally, it covers current global control measures, emerging treatment options, and the status of vaccines in development.

Brief communication

Four genotypes of carbapenem-resistant Acinetobacter baumannii strains lacking OXA-23 production in Korea

Young Ah Kim, Seok Hoon Jeong, Jong Hee Shin, Kyeong Seob Shin, Jeong Hwan Shin, Young Ree Kim, Hyun Soo Kim, Young Uh, Nam Hee Ryoo

Ann Clin Microbiol 2024 June, 27(2):143-147. Published on 20 June 2024.

During nationwide Fantimicrobial surveillance (Korea Global Antimicrobial Resistance Surveillance System [Kor-GLASS]), the recent emergence of non-oxacillinase (OXA)-23 production by carbapenem-resistant Acinetobacter baumannii (CRAB) isolates was noted. In this study, we evaluated resistance mechanisms other than OXA-23 production to elucidate the shift in considerable CRAB clones. The presence of OXA carbapenemase genes, such as blaOXA-23, blaOXA-24, blaOXA-58, and blaOXA-51-ISAba1, was determined by PCR. Other carbapenemase genes, such as blaIMP, blaVIM, blaNDM, blaKPC, blaGES, and blaOXA-48 , were determined using sequencing. Strains lacking carbapenemase genes were subjected to whole genome sequencing, and resistance genes were analyzed using ResFinder. Four CRAB strains were collected through a Kor-GLASS study in 2022, in which OXA-23 production was not identified. The carbapenemase genotypes of the four CRAB strains lacking blaOXA-23 were blaOXA-51-ISAba1, blaOXA-66/ACD25, blaOXA-182, and blaNDM-1. To the best of our knowledge, this is the f irst study to identify CRAB producing New Delhi metallo-β-lactamase (NDM)-1 in Korea. In conclusion, domestic CRAB resistance mechanisms may undergo subtle changes. Continuous observations are required to monitor the emergence of new clones.
Case report

Can Acanthamoeba keratitis be properly diagnosed without culture in the real-world clinical microbiology laboratory?: a case report

Bosung Park, Ho Seok Chung, Eun Jeong Won, Heungsup Sung, Mi-Na Kim

Ann Clin Microbiol 2024 June, 27(2):149-153. Published on 20 June 2024.

Acanthamoeba species are ubiquitous, free-living organisms found in the environment. They can cause a sight-threatening cornea disease, termed Acanthamoeba keratitis, and are often misdiagnosed, causing delayed administration of the correct treatment. Herein, we report a case of Acanthamoeba keratitis diagnosed without culture. A 12-year-old girl with a history of wearing contact lenses presented with complaints of pain, irritation, and hyperemia in the left eye. Corneal scraping-smeared slide, and liquids with contact lenses were submitted to the clinical microbiology laboratory. Cultures of Acanthamoeba spp. were not available; thus, they were stained with calcofluor white. The isolation of Acanthamoeba from the corneal scraping allowed the detection of trophozoites and cysts based on their morphological characteristics. PCR targeting the 18s rRNA gene and subsequent sequencing revealed 99% identity with the Acanthamoeba spp. Although it is challenging to find real-world evidence of Acanthamoeba in clinical microbiology without using culture methods, this case underscores the need for clinical microbiology laboratories to maintain their inspection capabilities.