case report

Bacterial Meningitis and Strongyloides Hyperinfection Syndrome in an Immunocompetent Adult: A Case-Based Review

Authors: Laia Mas1, Marina Alguacil2, Oriol Gasch3*

*Corresponding Author: Oriol Gasch Blasi, Department of Infectious Diseases. Parc Taulí Hospital Universitari, Sabadell, Barcelona, Spain.

Received Date: 24 December, 2021

Accepted Date: 28 December, 2021

Published Date: 31 December, 2021

Citation: Mas L, Alguacil M, Gasch O (2021) Bacterial Meningitis and Strongyloides Hyperinfection Syndrome in an Immunocompetent Adult: A Case-Based Review. Ann Case Report 6: 725. DOI:


Strongyloides hyperinfection syndrome (SHS) is caused by an accelerated autoinfection cycle of the parasite, frequently observed in immunocompromised hosts. However, it has rarely been described in immunocompetent patients. Penetration of intestinal mucosa by filariform larvae facilitates the transport of enteric organisms into the bloodstream, leading to extraintestinal bacterial infection such as meningitis. We present a case of a 79-year-old Bolivian immunocompetent male with SHS and meningitis due to Lactobacillus rhamnosus, and a literature review of the few cases reported of bacterial meningitis associated with SHS in immunocompetent patients. To our knowledge, this is the first case of Lactobacillus meningitis in association with SHS described in the literature.

Keywords: Lactobacillus meningitis; Strongyloides hyperinfection; Strongyloides stercolaris; Strongyloidiasis.

Abbreviations: CT: Computerized tomography; CSF: Cerebrospinal fluid; PCR: Polymerase Chain Reaction); b.i.d: bis in die - twice a day; HIV: Human Immunodeficiency Virus; HTLV- 1: human T-cell lymphotropic virus type 1; SHS: Strongyloides hyperinfection syndrome

Case Report

A 79-year-old Bolivian male with diabetes (glycated hemoglobin 7.5%) was admitted to the emergency department because of cephalea and confusion for two days. Three years ago, he had been diagnosed with interstitial lung disease with no evident cause (Figure 1). The studies performed showed normal pulmonary function tests, IgE increase > 5000UI/mL and oscillating eosinophilia. The patient did not accept the performance of bronchoscopy or lung biopsy. He also referred a 2-year history of diarrhea and pruritus. Previous outpatient investigations included a negative stool culture, 1 of 3 parasitic stool tests positive for Dientamoeba fragilis (treated with metronidazole), a normal abdominal computerized tomography (CT), and a colonoscopy showing active mild chronic colitis. He did not receive any immunosuppressive treatment for the last 18 months (previously, he had been treated with oral corticosteroids for an acute bronchitis). He had immigrated from Bolivia to Spain 18 years earlier, not travelling abroad since then.

Physical examination revealed a hemodynamically stable febrile patient. He was confused and lethargic, with no other neurological abnormalities. Significant laboratory findings included leukocytosis (12.48x109/L) with neutrophilia but normal eosinophil count, hemoglobin 117g/L and mild thrombocytosis (409x109/L). Brain CT showed previous lacunar strokes. The cerebrospinal fluid (CSF) analysis was consistent with acute bacterial meningitis (leukocyte count of 2,070/mm3 of which 84% were polymorphonuclear cells, glucose level of 45mg/dL, proteins at 2.14 g/L). He was started on dexamethasone 12mg intravenous, cefotaxime 300mg/kg/day, and ampicillin 250mg/kg/day. On the

next day, a multiplex Polymerase Chain Reaction (PCR) assay (Meningitis/Encephalitis FilmArray® panel) was performed in the CSF, discarding the most frequent pathogens of cerebral nervous system infection, including viruses, bacteria, and yeast. Ampicillin and corticoid were stopped, and cephalosporin was switched to ceftriaxone 2g b.i.d. Blood cultures were negative, but in CSF culture grew cephalosporine-resistant Lactobacillus rhamnosus. A lumbar puncture on day eleven showed a CSF examination with leukocyte count of 123/mm3 (99% polymorphonuclear cells), glucose level of 85mg/dL, proteins at 0.83 g/L.

Concurrently, screening serologic tests were performed, detecting IgG antibodies to Strongyloides stercolaris, and test stool samples were collected for parasitological examination to study the chronic diarrhea. Microscopic examination was performed after concentration techniques (Parasep®SF) and showed the presence of rhabditifom larvae of S stercolaris, which were also observed with the agar plate culture method for diagnosis of S stercolaris (Figure 2). The diagnosis of SHS with meningitis due to L rhamnosus was made, so ivermectin 200μg/kg/ day and linezolid 600mg b.i.d were added.

HIV and HTLV-1 serology were negative, and no nutrient deficiencies were found. An induced sputum was obtained for agar plate culture of S stercolaris and direct microscopic examination, and no larvae were found. However, the sputum sample was collected when the patient was under ivermectin therapy. He received ivermectin for 14 days, after which stool examination did not show parasites. CSF examination on day 17 showed leukocyte count of 43/ mm3 of which 100% were mononuclear cells, glucose level of 84mg/dL, proteins at 0.64 g/L and negative culture. He was discharged with resolution of neurological symptoms, pruritus, and diarrhea.


Strongiloydes stercolaris infection is more frequent in tropical and subtropical regions. However, because of migration and immunosuppressive therapies, increasing number of cases are being detected in developed countries. This intestinal nematode can penetrate the duodenal mucosa or perianal skin to access venous circulation (autoinfection). This phenomenon is unique to this parasite, and it is seen in both asymptomatic and symptomatic hosts, where continuous cycles may perpetuate the infection for decades. However, in some immunocompromised hosts the parasite begins to replicate through an accelerated autoinfection cycle, causing more severe forms of the disease, known as Strongyloides hyperinfection syndrome (SHS). Penetration of intestinal mucosa by filariform larvae facilitates the transport of enteric organisms into the bloodstream, leading to extraintestinal bacterial infection such as meningitis. CSF can exhibit an aseptic meningitis or bacterial meningitis characteristics. CSF cultures are usually positive for enteric organisms, such as E. coli, P. mirabilis, K. pneumoniae or E. faecalis [1]. To our knowledge, this is the first case of Lactobacillus meningitis in association with SHS described in the literature. The most common risk factors for the SHS are coinfection with HTLV-1 or HIV, treatment with corticosteroids, transplants, alcoholism, or malnutrition [1]. It is infrequently described in immunocompetent adults [2]. In our patient we did not identify any immunological alteration other than diabetes. This chronic disease is present in a few case reports of disseminated strongyloidiasis [2,3] and has been associated with treatment failure [4], but increased risk of SHS has not been reported. However, the association between diabetes and Strongyloides infection remains controversial with both positive and negative associations demonstrated in previous studies [5-7]. Few cases of bacterial meningitis associated with SHS in immunocompetent patients have previously been described in the literature (Table 1) [8-11]. As a whole, most patients came from regions where S stercolaris is more prevalent. Eosinophilia was not observed in any case, as in our patient. Comorbidities were described only in two cases, and diabetes was present in both.

In conclusion, although it is more frequent in immunocompromised hosts, SHS can occur in immunocompetent individuals. This case highlights the need for suspecting SHS in an enteric meningitis in a patient with a consistent epidemiological background, despite the absence of immunological alterations.


This project was financed by Instituto de Salud Carlos III/ FEDER (Expedient PI17/02102)


Figure 1: CT Scan showing interstitial lung disease.

Figure 2: Agar plate culture showing larvae of S. stercolaris.





Country of origin



CSF analysis

CSF culture

Blood cultures

Diagnosis Strongyloides


F. Reyes et al., IDCases. (2017)





Hypertension, type 2 DM, dyslipidemia, hypothyroidism, ischemic stroke, asthma

Raised white cell count (85% neutrophils).

Citrobacter koserii

Citrobacter koserii

Necropsy (gastrointestinal tract, respiratory tract and in the meninges).


Vandebosch et al., Acta Gastroenterol Belg (2008)





hypertension, type 2 DM


Five episodes of meningitis in one patient (Strepto-coccus anginosus yield in one).


duodenal biopsies


Hager et al., W V Med J (2007)



USA (rural community)



raised white cell count (74% neutrophils) and protein (706mg/dL), and low glucose (23mg/dL)

Strepto-coccus bovis

Strepto-coccus bovis



Smallman LA et al., J Clin Pathol (1986)

Case 1





Described as pus (Diagnostic of meningitis by necropsy)

Escherichia coli

Escherichia coli

biopsy of distal ileum, stool, and nasogastric, pharyngeal, and tracheal aspirates.


Case 2


West Indian



raised white cell count (neutrophils, polymorphs), low glucose concen-tration.

Escherichia coli


Necropsy (biopsy of duodenum, jejunum, and ileum).


CSF Cerebrospinal fluid

Table 1: Literature review of bacterial meningitis associated with SHS in immunocompetent patients.


  1. Vasquez-Rios G, Pineda-Reyes R, Pineda-Reyes J, Marin R, Ruiz EF, et al. (2019) Strongyloides stercoralis hyperinfection syndrome: a deeper understanding of a neglected disease. J Parasit Dis. 43:167-175.
  2. Chan FLY, Kennedy B, Nelson R. (2018) Fatal Strongyloides hyperinfection syndrome in an immunocompetent adult with review of the literature. Intern Med J. 48: 872-875.
  3. Murali A, Rajendiran G, Ranganathan K, Shanthakumari S. (2010) Disseminated infection with Strongyloides stercoralis in a diabetic patient. Indian J Med Microbiol. 28: 407-408.
  4. Hays R, Esterman A, McDermott R. (2015) Type 2 diabetes mellitus is associated with Strongyloides stercoralis treatment failure in Australian aboriginals. 9.
  5. Mendonça SCL, Gonçalves-Pires M do RF, Rodrigues RM, Ferreira Á, Costa-Cruz JM. (2006) Is there an association between positive Strongyloides stercoralis serology and diabetes mellitus? Acta Trop. 99:102-105.
  6. Hays R, Esterman A, Giacomin P, Loukas A, McDermott R. (2015) Does Strongyloides stercoralis infection protect against type 2 diabetes in humans? Evidence from Australian Aboriginal adults. Diabetes Res Clin Pract. 107: 355-361.
  7. McGuire E, Welch C, Melzer M. (2019) Is Strongyloides seropositivity associated with diabetes mellitus? A retrospective case-control study in an East London NHS Trust. Trans R Soc Trop Med Hyg. 113: 189-194.
  8. Smallman LA, Young JA, Shortland-Webb WR, Carey MP, Michael J. (1986) Strongyloides stercoralis hyperinfestation syndrome with Escherichia coli meningitis: Report of two cases. J Clin Pathol. 39: 366-370.
  9. Hager C, Abaaba C, Kerns F. (2007) Steptococcus bovis meningitis and sepsis associated with Strongyloidiasis in an immunocompetent patient. W V Med J. 103: 19-21.
  10. Vandebosch S, Mana F, Goossens A, Urbain D. (2008) Strongyloides stercoralis infection associated with repititive bacterial meningitis and SIADH: A case report. Acta Gastroenterol Belg. 71: 413-417.
  11. Reyes F, Singh N, Anjuman-Khurram N, Lee J, Chow L. (2017) Strongyloides Hyperinfection Syndrome causing fatal meningitis and septicemia by Citrobacter koseri. IDCases. 10:102-104.

© by the Authors & Gavin Publishers. This is an Open Access Journal Article Published Under Attribution-Share Alike CC BY-SA: Creative Commons Attribution-Share Alike 4.0 International License. With this license, readers can share, distribute, download, even commercially, as long as the original source is properly cited. Read More.

Annals of Case Reports

pola slot gacor zeusslot gacor mudah jackpotslot sugar rushslot mahjong thailandmahjong scatter naga hitamslot mahjong ways 2slot pg soft gacorprediksi judi bola sbobetparlay sbobet euro 2024rtp pg softbocoran rtp dan pola gacoragen bola euro terpercayatrik slot mahjong ways 2trik menaklukkan slot mahjong waysbandar bola terpercayaslot gacor gampang menangslot olympus 1000jam gacor pragmaticslot gacor mudah maxwinagen judi bola resmimahjong ways pola jitu maxwinpola gacor starlight princessslot server kambojarahasia scatter hitam mahjong waysturbo spin slot mahjongrtp slot candy villagepola gacor mahjong wins terbaruslot server luar terbarurtp slot olympusslot mahjong waysrtp sweet bonanzaagen sbobet euro 2024judi bola parlay sbobetslot gates of olympus jepe maxwinrtp slot gacorslot starlight christmas pragmatic