Diagnosis, Diagnostics, Immunodiagnosis & Immunodiagnostics:
Abstracts
January 2003
5925.
Garcia LS, Shimizu RY, Bernard CN. Detection of Giardia lamblia,
Entamoeba histolytica/Entamoeba dispar, and Cryptosporidium parvum antigens in
human fecal specimens using the triage parasite panel enzyme immunoassay. J Clin
Microbiol 2000 Sep;38(9):3337-40
The
Triage parasite panel (BIOSITE Diagnostics, San Diego, Calif.) is a new
qualitative enzyme immunoassay (EIA) panel for the detection of Giardia lamblia,
Entamoeba histolytica/E. dispar, and Cryptosporidium parvum in fresh or fresh,
frozen, unfixed human fecal specimens. By using specific antibodies, antigens
specific for these organisms are captured and immobilized on a membrane. Panel
performance was evaluated with known positive and negative stool specimens (a
total of 444 specimens) that were tested by the standard ova and parasite
(O&P) examination as the "gold standard," including staining with
both trichrome and modified acid-fast stains. Specimens with discrepant results
between the reference and Triage methods were retested by a different method,
either EIA or immunofluorescence. A number of samples with discrepant results
with the Triage device were confirmed to be true positives. After resolution of
discrepant results, the number of positive specimens and the sensitivity and
specificity results were as follows: for G. lamblia, 170, 95.9%, and 97.4%,
respectively; for E. histolytica/E. dispar, 99, 96.0%, and 99.1%, respectively;
and for C. parvum, 60, 98.3%, and 99.7%, respectively. There was no
cross-reactivity with other parasites found in stool specimens, including eight
different protozoa (128 challenges) and three different helminths (83
challenges). The ability to perform the complete O&P examination should
remain an option for those patients with negative parasite panel results but who
are still symptomatic.
5926.
Misra A, Agrahari D, Gupta R. Cullen's sign in amoebic liver abscess.
Postgrad Med J 2002
Jul;78(921):427-8
A
45 year old woman presented with pain in her right upper abdomen and fever.
Ultrasound of her abdomen showed a large liver abscess with subhepatic
collection. She had Cullen's sign. The liver abscess was managed by percutaneous
catheter drainage.
5927.
Schunk M, Jelinek T, Wetzel K, Nothdurft HD. Detection of Giardia lamblia
and Entamoeba histolytica in stool samples by two enzyme immunoassays. Eur J
Clin Microbiol Infect Dis 2001
Jun;20(6):389-91.
Two
commercially produced enzyme immunoassays (EIAs) to detect antigens of
-
Giardia lamblia and Entamoeba histolytica in stool specimens were evaluated. A
total of 276 stool specimens were collected from patients who presented with
various medical complaints in the outpatient clinic of the Department of
Infectious Diseases and Tropical Medicine, University of Munich. Every specimen
was examined by conventional microscopy and tested by both EIA kits. When
microscopy was used as the reference standard, the EIA kit detecting Giardia
lamblia showed a sensitivity of 100% and a specificity of 99.6%. The EIA kit
detecting Entamoeba histolytica had a sensitivity of 81.8% and a specificity of
99.2%. Both tests showed no cross-reactivity with other intestinal protozoa.
Antigen detection by EIA has the potential to become a valuable tool capable of
making stool diagnostics more effective, although it should not be considered as
a replacement for microscopic examination, since other potential pathogens could
otherwise escape detection.
5928.
Sharp SE, Suarez CA, Duran Y, Poppiti RJ. Evaluation of the Triage Micro
Parasite Panel for detection of Giardia lamblia, Entamoeba histolytica/Entamoeba
dispar, and Cryptosporidium parvum in patient stool specimens. J Clin Microbiol
2001 Jan;39(1):332-4
A
study comparing the Triage Micro Parasite Panel (Biosite Diagnostics, Inc., San
Diego, Calif.) to conventional O&P examination (O&P) was performed using
patient fecal specimens. Five hundred twenty-three stool samples were compared.
Nineteen specimens were found to be positive by Triage, and 29 were found to be
positive by O&P. Seven specimens were positive for Giardia lamblia, four
were positive for Entamoeba histolytica/E. dispar, and three were positive for
Cryptosporidium parvum as determined by both methods. There was one false
positive by Triage (C. parvum) and four false negatives by O&P (two G.
lamblia, one E. histolytica/E. dispar, and one C. parvum). The Triage test
accurately detected all 18 specimens that contained one of the three organisms
that it was designed to detect. The Triage test is a rapid, easy-to-use enzyme
immunoassay for the detection of G. lamblia, E. histolytica/E. dispar, and C.
parvum in fresh or fresh-frozen fecal specimens. These data suggest that the
Triage test can be used as a screen for the immediate testing of stool specimens
for these three pathogenic parasites. If Triage test results are negative,
O&P can be performed if parasitic infections other than G. lamblia, E.
histolytica/E. dispar, or C. parvum are suspected.
Pathogenesis:
5929.
Haque R, Duggal P, Ali IM, Hossain MB, Mondal D, Sack RB, Farr BM, Beaty
TH, Petri WA Jr. Innate and acquired resistance to amebiasis in bangladeshi
children. J Infect Dis 2002 Aug
15;186(4):547-52.
Entamoeba
histolytica infection and colitis occurred in 55% and 4%, respectively, of a
cohort of Bangladeshi preschool children observed for 2 years. DNA typing
demonstrated that infecting E. histolytica isolates were genetically diverse.
Innate resistance to infection in children was linked to the absence of serum
anti-trophozoite IgG. Most children who lacked serum anti-trophozoite IgG failed
to develop it in response to a new infection. The serum anti-trophozoite IgG
response clustered in families, which is consistent with genetic inheritance.
Acquired resistance to infection was linked to intestinal IgA against the
carbohydrate-recognition domain of the E. histolytica galactose N-acetyl-d-galactosamine
lectin. This was associated with an 86% reduction in new infection over 1 year.
Amebiasis is a common and potentially serious infection in children from Dhaka,
and both innate and acquired immune responses limit infection.
5930.
Khan NA, Jarroll EL, Paget TA. Molecular and physiological
differentiation between pathogenic and nonpathogenic Acanthamoeba. Curr
Microbiol 2002 Sep;45(3):197-202
In
this study, 14 isolates of Acanthamoeba from both clinical and environmental
sources belonging to seven different species were assayed for tolerance of high
osmotic pressure, temperature tolerance, extracellular proteases, and cytopathic
effects (CPE) on immortalized rabbit corneal epithelial cells. On the basis of
the results, amoeba isolates were divided into pathogenic and nonpathogenic
groups. Ribosomal DNA sequencing was performed on these isolates. Phylogenetic
relationships revealed that all the pathogenic strains tested clustered together
as one group, while nonpathogenic strains clustered into other groups. Sequence
comparisons with previously published sequences determined that among the six
new pathogenic isolates used in this study, five belong to T4 genotype and one
to T11. This is the first report of a T11 genotype being found in Acanthamoeba
keratitis.
5931.
Rivera MA, Padhya TA. Acanthamoeba: a rare primary cause of
rhinosinusitis. Laryngoscope 2002
Jul;112(7 Pt 1):1201-3
Parasitic
infections, especially Acanthamoeba, are rarely implicated as a specific cause
of rhinosinusitis. It is a fatal disease found in the immunocompromised
population, in particular in patients infected with the human immunodeficiency
virus (HIV). Less than 10 cases of Acanthamebic rhinosinusitis have been
reported in the literature, and only 1 has survived. This case report presents
an Acanthamebic infection misdiagnosed as a squamous cell carcinoma of the nasal
septum on a presumptive healthy, immunocompetent 35-year-old woman. She was
later diagnosed with AIDS (AIDS) along with disseminated Acanthamoebiasis and
became the second reported case surviving this deadly illness. This case report
also discusses the difficulty in diagnosing this rare parasite, the
pathogenesis, and the multidisciplinary treatment required to control and manage
this uniformly fatal disease.
5932.
Schuster FL. Cultivation of pathogenic and opportunistic free-living
amebas. Clin Microbiol Rev 2002
Jul;15(3):342-54.
Free-living
amebas are widely distributed in soil and water, particularly
-
members of the genera Acanthamoeba and NAEGLERIA: Since the early 1960s, they
have been recognized as opportunistic human pathogens, capable of causing
infections of the central nervous system (CNS) in both immunocompetent and
immunocompromised hosts. Naegleria is the causal agent of a fulminant CNS
condition, primary amebic meningoencephalitis; Acanthamoeba is responsible for a
more chronic and insidious infection of the CNS termed granulomatous amebic
encephalitis, as well as amebic keratitis. Balamuthia sp. has been recognized in
the past decade as another ameba implicated in CNS infections. Cultivation of
these organisms in vitro provides the basis for a better understanding of the
biology of these amebas, as well as an important means of isolating and
identifying them from clinical samples. Naegleria and Acanthamoeba can be
cultured axenically in cell-free media or on tissue culture cells as feeder
layers and in cultures with bacteria as a food source. Balamuthia, which has yet
to be isolated from the environment, will not grow on bacteria. Instead, it
requires tissue culture cells as feeder layers or an enriched cell-free medium.
The recent identification of another ameba, Sappinia diploidea, suggests that
other free-living forms may also be involved as causal agents of human
infections.
Therapy:
5933.
Kumar R, Lloyd D. Recent advances in the treatment of Acanthamoeba
keratitis. Clin Infect Dis 2002 Aug
15;35(4):434-41
Infection
of the eye caused by Acanthamoeba species constitutes a burgeoning and unsolved
problem. Of individuals with Acanthamoeba keratitis, 85% wear contact lenses;
abrasion of the cornea is implicated. Corneal infection often can be prevented
by good lens care and hygiene. Severe Acanthamoeba keratitis often can be very
difficult to treat; surgery can be less than successful and may lead to further
problems. The encysted stage in the life cycle of Acanthamoeba species appears
to cause the most problems; many biocides are ineffective in killing the highly
resistant cysts. Combination therapy--that is, use of 2 or 3 biocides, sometimes
with antibacterial antibiotics--appears to work best. Recurrence is common if
treatment is stopped prematurely. Immunologic methods are being investigated as
a form of prevention, and oral immunization of animals recently has been
successful in the prevention of Acanthamoeba keratitis by inducing immunity
before infection occurs. Immunization thus may eventually become the best
approach for reduction of the incidence of amebic infection in humans.
5934.
Steinberg JP, Galindo RL, Kraus ES, Ghanem KG. Disseminated
acanthamebiasis in a renal transplant recipient with osteomyelitis and cutaneous
lesions: case report and literature review. Clin Infect Dis
2002 Sep 1;35(5):e43-9
Disseminated
acanthamebiasis is a rare disease that occurs predominantly in patients with
human immunodeficiency virus (HIV) infection or acquired immunodeficiency
syndrome but also in immunosuppressed transplant recipients. Few reports have
focused on non-HIV-infected patients, in whom the disease is more likely to go
unsuspected and undiagnosed before death. We describe a renal transplant
recipient with Acanthamoeba infection and review the literature. The patient
presented with osteomyelitis and widespread cutaneous lesions. No causative
organism was identified before death, despite multiple biopsies with detailed
histological analysis and culture. Disseminated Acanthamoeba infection was
diagnosed after death, when cysts were observed in histological examination of
sections of skin from autopsy, and trophozoites were found in retrospectively
reviewed skin biopsy and surgical bone specimens. In any immunosuppressed
patient, skin and/or bone lesions that fail to show improvement with
broad-spectrum antibiotic therapy should raise the suspicion for disseminated
acanthamebiasis. Early recognition and treatment may improve clinical outcomes.
5935.
Wiwanitkit V, Suwansaksri N, Suwansaksri J. Causative agents of liver
abscess in those with liver cirrhosis: a 10-year case review of hospitalized
patients in Thailand. Ann Trop Med Parasitol
2002 Jul;96(5):513-6
Although
patients with cirrhosis of the liver show relative immunosuppression and
therefore have increased susceptibility to most infections, they rarely develop
liver abscesses. In a retrospective case review, the pathogens causing the liver
abscesses observed, between January 1992 and December 2001 at the King
Chulalongkorn Memorial Hospital, Bangkok, Thailand, in 44 hospitalized patients
diagnosed as cases of liver cirrhosis were investigated. The most common
clinical symptoms and signs of the abscesses--abdominal pain (80%), fever and
chills (73%), and abdominal tenderness (73%)--were similar to those seen in
non-cirrhotic patients with abscesses. The frequency of liver abscess among the
cirrhotic patients was low (0.46%). Most (71%) of the abscesses were in the
right lobe and most (71%) of those with abscesses only had a single abscess.
Surprisingly, many of the abscesses (36%) were apparently caused by amoebae.
Bacterial pathogens were identified in eight patients (18%) by blood culture and
15 (34%) patients by pus culture. Seven (16%) of the blood cultures and 13 (30%)
of the pus contained Gram-negative aerobes, indicating that such pathogens,
particularly Klebsiella pneumoniae (in six pus and six blood cultures) and
Escherichia coli (in three pus cultures and one blood), were the most common
causes of the bacterial abscesses. Pus culture appeared more successful than
blood culture for bacterial abscesses, and amoebic abscesses could always be
identified by direct microscopical examination of pus samples. Aspiration of
liver abscesses, to obtain pus samples for culture and microscopy, is therefore
recommended.
April 2003
6545. Mahajan R C, Vohra V, Sehgal R, Ganguly N K. Immunodiagnosis of amoebiasis. Proc natn Acad Sci India –Sect b 2000 ,70(3-4),189-96. (isa 017220, Vol 38 No17 ,1 Sept 2002)
6546. McCarthy JS, Peacock D, Trown KP, Bade P, Petri Jr WA, Currie BJ. Endemic invasive amoebiasis in northern Australia. Med J Aust 2002 Nov 18;177(10):570 No abstract.
Pathogenesis:
6547.
Zhang Z, Duchene M, Stanley SL Jr. A monoclonal antibody to the amebic
lipophosphoglycan-proteophosphoglycan antigens can prevent disease in human
intestinal xenografts infected with Entamoeba histolytica. Infect Immun
2002 Oct;70(10):5873-6. Entamoeba
histolytica trophozoites are covered by lipophosphoglycan-peptidoglycan
molecules which may be key virulence factors. We found that pretreatment of
severe combined immunodeficient mice bearing human intestinal xenografts with a
monoclonal antibody to the amebic lipophosphoglycan-peptidoglycan molecules can
prevent or significantly reduce the human intestinal inflammation and tissue
damage that are normally seen with E. histolytica colonic infection.
July 2003
7057.
McGarr PL, Madiba TE, Thomson SR, Corr P. Amoebic liver abscess--results
of a conservative management policy. S Afr Med J
2003 Feb;93(2):132-6
OBJECTIVE:
To evaluate the safety and efficacy of conservative management of amoebic liver
abscesses. DESIGN: A prospective study carried out over a 1-year period.
SETTING: Inpatients and outpatients in a tertiary referral institution.
SUBJECTS: Amoebic liver abscess was diagnosed on clinical, ultrasonographic, and
serological features. All patients were treated with metronidazole. The
indication for ultrasound-guided aspiration of the abscess was failure to
improve clinically within 48-72 hours. MAIN OUTCOME MEASURES: Clinical
improvement, clinical deterioration and failure of clinical improvement
(persistent pain). RESULTS: In total 178 patients (male-to-female ratio 5:1)
with 203 abscesses were treated during this period. Of these, 23 patients
required percutaneous aspiration and 150 patients were managed without
intervention and clinically resolved spontaneously. Abscesses requiring
aspiration tended to be larger than those managed without aspiration (10.7 cm v.
8.2 cm) (p = 0.003). There were no complications following aspiration. Mean
hospital stay was longer (12.3 days) for patients who underwent aspiration
compared with those who did not (6.7 days) (p = 0.031). Only 5 patients
presented with ruptured abscesses, 1 cutaneously and 4 intraperitoneally, with
the only death in this latter category. CONCLUSION: Conservative medical
management of amoebic liver abscess is safe. Percutaneous ultrasound-guided
aspiration is indicated only in patients who fail to improve clinically after
48-72 hours rather than on rigid criteria.
7058.
Schwarzwald H, Shah P, Hicks J, Levy M, Wagner ML, Kline MW. Disseminated
Acanthamoeba infection in a human immunodeficiency virus-infected infant.
Pediatr Infect Dis J 2003
Feb;22(2):197-9
Infection
with Acanthamoeba is difficult to diagnose and treat. We present the first case
of disseminated Acanthamoeba infection in an HIV-infected infant. The infant
survived 2 years with treatment with several agents having anti-Acanthamoeba
activity in vitro.
7059.
Stanley SL Jr. Amoebiasis. Lancet 2003
Mar 22;361(9362):1025-34.
Amoebiasis
is the second leading cause of death from parasitic disease worldwide. The
causative protozoan parasite, Entamoeba histolytica, is a potent pathogen.
Secreting proteinases that dissolve host tissues, killing host cells on contact,
and engulfing red blood cells, E histolytica trophozoites invade the intestinal
mucosa, causing amoebic colitis. In some cases amoebas breach the mucosal
barrier and travel through the portal circulation to the liver, where they cause
abscesses consisting of a few E histolytica trophozoites surrounding dead and
dying hepatocytes and liquefied cellular debris. Amoebic liver abscesses grow
inexorably and, at one time, were almost always fatal, but now even large
abscesses can be cured by one dose of antibiotic. Evidence that what we thought
was a single species based on morphology is, in fact, two genetically distinct
species--now termed Entamoeba histolytica (the pathogen) and Entamoeba dispar (a
commensal)--has turned conventional wisdom about the epidemiology and diagnosis
of amoebiasis upside down. New models of disease have linked E histolytica
induction of intestinal inflammation and hepatocyte programmed cell death to the
pathogenesis of amoebic colitis and amoebic liver abscess.
Pathogenesis:
7060.
Kumar CS, Anand Kumar H, Sunita V, Kapur I. Prevalence of anemia and worm
infestation in school going girls at Gulbargha, Karnataka. Indian Pediatr 2003 Jan;40(1):70-2 No
abstract available.
October 2003
7793.
Ali IK, Hossain MB, Roy S, Ayeh-Kumi PF, Petri WA Jr, Haque R, Clark CG.
Entamoeba moshkovskii infections in children, Bangladesh. Emerg Infect Dis. 2003
May;9(5):580-4.
Entamoeba
moshkovskii cysts are morphologically indistinguishable from those of the
disease-causing species E. histolytica and the nonpathogenic E. dispar. Although
sporadic cases of human infection with E. moshkovskii have been reported, the
organism is considered primarily a free-living amoeba. No simple molecular
detection tool is available for diagnosing E. moshkovskii infections. We used
polymerase chain reaction (PCR) to detect E. moshkovskii directly in stool. We
tested 109 stool specimens from preschool children in Bangladesh by PCR; 17 were
positive for E. histolytica (15.6%) and 39 were positive for E. dispar (35.8%).
In addition, we found that 23 (21.1%) were positive for E. moshkovskii
infection, and 17 (73.9%) of these also carried E. histolytica or E. dispar. The
high association of E. moshkovskii with E. histolytica and E. dispar may have
obscured its identification in previous studies. The high prevalence found in
this study suggests that humans may be a true host for this amoeba.
7794.
Haque R, Huston CD, Hughes M, Houpt E, Petri WA Jr. Amebiasis. N Engl J
Med. 2003 Apr 17;348(16):1565-73. No
abstract
7795.
Haseeb AN, el-Shazly AM, Arafa MA, Morsy AT. Evaluation of
excretory/secretory Fasciola (Fhes) antigen in diagnosis of human fascioliasis.
J Egypt Soc Parasitol. 2003 Apr;33(1):123-38.
No
doubt, human fascioliasis is an increasing worldwide zoonotic liver fluke.
Clinically, human fascioliasis has to be differentially diagnosed from many
hepatic diseases as acute & chronic hepatitis, schistosomiasis mansoni,
visceral toxocariasis, visceral leishmaniasis, hepatic amoebiasis, biliary tract
diseases and others. The parasitological diagnosis based on the demonstration of
the eggs in stool, duodenal contents or bile is usually unsatisfactory due to
false passage of eggs, ectopic fascioliasis, and failure of immature worm to
maturation. So, ELISA-Fhes antigen (Fasciola hepatica excretory/secretory) and
IHAT were evaluated in the immunodiagnosis of parasitologically proven cases of
human fascioliasis compared with proven cases of human schistosomiasis mansoni
and parasite-free individuals. ELISA-Fhes gave 100% sensitivity and 100%
specificity. On the other hand, IHAT was less sensitive and less specific.
7796.
Hoda SA, Ali A. Images in pathology. Food for thought! Vegetable cells in
histopathological sections. Int J Surg Pathol. 2003 Apr;11(2):120. No
abstract.
Pathogenesis:
7797.
Marciano-Cabral F, Cabral G. Acanthamoeba spp. as agents of disease in
humans. Clin Microbiol Rev. 2003 Apr;16(2):273-307.
Acanthamoeba
spp. are free-living amebae that inhabit a variety of air, soil, and water
environments. However, these amebae can also act as opportunistic as well as
nonopportunistic pathogens. They are the causative agents of granulomatous
amebic encephalitis and amebic keratitis and have been associated with cutaneous
lesions and sinusitis. Immuno compromised individuals, including AIDS patients,
are particularly susceptible to infections with Acanthamoeba. The immune defense
mechanisms that operate against Acanthamoeba have not been well characterized,
but it has been proposed that both innate and acquired immunity play a role. The
ameba's life cycle includes an active feeding trophozoite stage and a dormant
cyst stage. Trophozoites feed on bacteria, yeast, and algae. However, both
trophozoites and cysts can retain viable bacteria and may serve as reservoirs
for bacteria with human pathogenic potential. Diagnosis of infection includes
direct microscopy of wet mounts of cerebrospinal fluid or stained smears of
cerebrospinal fluid sediment, light or electron microscopy of tissues, in vitro
cultivation of Acanthamoeba, and histological assessment of frozen or
paraffin-embedded sections of brain or cutaneous lesion biopsy material.
Immunocytochemistry, chemifluorescent dye staining, PCR, and analysis of DNA
sequence variation also have been employed for laboratory diagnosis. Treatment
of Acanthamoeba infections has met with mixed results. However, chlorhexidine
gluconate, alone or in combination with propamidene isethionate, is effective in
some patients. Furthermore, effective treatment is complicated since patients
may present with underlying disease and Acanthamoeba infection may not be
recognized. Since an increase in the number of cases of Acanthamoeba infections
has occurred worldwide, these protozoa have become increasingly important as
agents of human disease.
7798.
Zardawi IM, Kattampallil JS, Rode JW. Amoebic appendicitis. Med J Aust.
2003 May 19;178(10):523-4. No abstract
Therapy:
7799.
Ooi BS, Seow-Choen F. Endoscopic view of rectal amebiasis mimicking a
carcinoma. Tech Coloproctol. 2003 Apr;7(1):51-3.
We
report the case of a 45-year-old man with rectal amebiasis, presenting with
rectal bleeding and chronic diarrhea, confirmed on rectal biopsy. The endoscopic
view was highly suggestive of a carcinoma and caused confusion about its
etiology. The striking difference in the endoscopic view before and after
medical therapy of the tumor-like lesion was remarkable. This case illustrates
the importance of an accurate histologic diagnosis before definitive treatment
and highlights the mimicry of rectal carcinoma by rectal amebiasis on endoscopy.