This is a case of gastrointestinal
Talaromyces marneffei infection with negative blood culture, and the absence of any respiratory involvement or rash. The mNGS rapidly aided in identifying
Talaromyces marneffei nucleotide sequences in omentum majus FFPE samples from our patient, which had never been previously reported; In 3 previous published papers, mNGS has been reported to help to diagnose
Talaromyces marneffei infection in the bronchoalveolar lavage fluid [
2,
3], bone marrow [
2], cerebrospinal fluid [
2,
4], and skin lesion [
2] specimens.
Talaromyces marneffei is a common opportunistic infection among HIV-infected patients in southeast Asia, southern China, and northeastern India, which are endemic areas for
Talaromyces marneffei. Possible epidemiological risk factors are as follows: (1) a history of travel or living in endemic areas and soil exposure, especially during the rainy season, has been suggested to be a critical risk factor; (2) people living with HIV infection, especially CD4
+ T-cell counts below 200cells/μL, contributes to an increased risk of
Talaromyces marneffei infection. Common manifestations of disseminated
Talaromyces marneffei include fever, anemia, weight loss, skin lesions, respiratory signs, lymphadenopathy, and hepatosplenomegaly. Characteristic cutaneous lesions aids to diagnosis and
Talaromyces marneffei infection can be confirmed by positive culture from blood, skin lesion, and bone marrow samples [
5]. Inhalation of conidia is the primary route of infection, which then disseminates to the reticuloendothelial system, skin, and gastrointestinal organs. Although gastrointestinal symptoms (e.g., diarrhea) are relatively common with a prevalence of approximately 25% [
6], the prevalence of colonic involvement caused by
Talaromyces marneffei infection is only 1.9% [
7]. Including the present case, prominent abdominal involvement from
Talaromyces marneffei infection has been reported in a total of 14 patients (Table
1) [
4‐
13]. The main macroscopic pathological changes include multiple gastrointestinal ulcers and mesenteric lymphadenitis. Common distribution of colonic infections include the cecum, ascending colon, appendix, transverse colon, descending colon, or sigmoid colon, small intestine, and duodenum. Common clinical manifestations are fever, diarrhea, abdominal pain, lower gastrointestinal bleeding, and intestinal obstruction. Most patients survive with anti-fungal treatment. Wild bamboo rats exhibit a 100% prevalence of
Talaromyces marneffei infection [
14]. It is important to note that the bamboo rat is a common species of rodent bred for meat and wool in southern China. The potential for bamboo rats to transmit pathogens to humans remains unclear because most patients with
Talaromyces marneffei infection in Guangdong did not have a history of contact with bamboo rats [
15]. Although the patient’s history of bamboo rat consumption is very suggestive, the link between bamboo rat ingestion history in this case and predominantly gastrointestinal presentation requires further study.
Table 1
Summary of clinical characteristics for 14 HIV-infected cases with intestinal Talaromyces marneffei
1 | 72/M | Hong Kong China | GI bleeding | anorexia, dysphagia, weight loss | jejunal ulcer(S) | small intestine(B + C), mesenteric lymph node, liver(A) | NM | Died |
2 | 32/M | Hong Kong | diarrhea | fever, night sweats, dry cough | multiple solitary ulcers(E) | cecum, transverse and descending colon(B + C) | Amphotericin B/Itraconazole | survived |
3、4 | NM | | abdominal pain | fever | NM | mesenteric lymph node (B), blood and bone marrow (C) | Amphotericin B | survived |
5 | 52/M | Taiwan | diarrhea, abdominal pain | fever, erupted papule, anomia, | shallow ulcers(E) | skin, bone marrow(B + C), colons(B) | Amphotericin B/Itraconazole | survived |
6 | 30/M | Taiwan | diarrhea, abdominal pain, bloody stool | dyspepsia, fever, anomia, weight loss | shallow ulcers(E) | cecum, ascending and transverse colons(B + C) | Amphotericin B/Itraconazole | survived |
7 | 33/M | | abdominal pain | fever, loss of appetite, weight loss, vomiting | duodenum narrowing(E) | duodenum(B + C), bone marrow(C) | Amphotericin B/Itraconazole | survived |
8 | 39/M | Hong Kong | Abdominal pain | fever, weight loss | perioral umbilicated lesions | neck and retroperitoneal lymph nodes (H + C),blood (C) | Amphotericin B/Itraconazole | Survived |
9 | 28/M | | non-colicky abdominal pain | fever, weight loss | perioral umbilicated lesions | neck nodes and retroperitoneal lymph nodes(B + C), blood(C) | Amphotericin B/Itraconazole | survived |
10 | 52/M | | pain in the lower left abdomen | anorexia, weight loss | multiple solitary shallow ulcers (E) | transverse colon (B + H) | Itraconazole | survived |
11 | 38/F | | colicky abdominal pain | loss of appetite, weight loss | skin lesions, jejunal ulcers(E) | skin, jejunal ulcers(B + C), | Amphotericin B/Itraconazole | survived |
12 | 37/M | | Abdominal pain | NM | multiple ulcers (E) | colon (B), blood (C) | Amphotericin B/Itraconazole | Survived |
13 | 50/M | | Abdominal pain | weight loss | multiple ulcers (E) | colon (B) | Voriconazole+Amphotericin B/Itraconazole | Survived |
14 | 33/M | China [PR] | colicky abdominal pain, bloody stool | fever, weight loss, night sweats | colon ulcers(E) | Mesenteric lymph node(B + N) | Amphotericin B/Itraconazole | survived |
In conclusion, as a type of culture-independent method, mNGS provides a rapid etiological diagnosis, especially in patients with an uncommon presentation of Talaromyces marneffei infection. FFPE samples of lesions and fresh biopsy specimens may represent suitable specimens for mNGS, which may be convincing for obtaining a targeted diagnosis and treatment.