Roongnapa Pracharktam

Clinical and Epidemiological Analyses of Human Pythiosis in Thailand

BACKGROUND Pythiosis is an emerging and life-threatening infectious disease in humans and animals that is caused by the pathogenic oomycete Pythium insidiosum. Human pythiosis is found mostly in Thailand, although disease in animals has been increasingly reported worldwide. Clinical information on human pythiosis is limited, and health care professionals are unfamiliar with the disease, leading to underdiagnosis, delayed treatment, and poor prognosis. METHODS To retrospectively study the clinical and epidemiological features of human pythiosis, we analyzed clinical data from patients with pythiosis diagnosed during the period of January 1985 through June 2003 at 9 tertiary care hospitals throughout Thailand. RESULTS A total of 102 cases of human pythiosis were documented nationwide. A substantial proportion (40%) of cases occurred in the last 4 years of the 18-year study interval. Clinical presentations fell into 4 groups: cutaneous/subcutaneous cases (5% of cases), vascular cases (59%), ocular cases (33%), and disseminated cases (3%). Almost all patients with cutaneous/subcutaneous, vascular, and disseminated pythiosis (85%) had underlying thalassemia-hemoglobinopathy syndrome. Most ocular cases (84%) were associated with no underlying disease. A majority of the patients were male (71%), were aged 20-60 years (86%), and reported an agricultural occupation (75%). Regarding treatment outcomes, all patients with disseminated infection died; 78% of patients with vascular disease required limb amputation, and 40% of these patients died; and 79% of patients with ocular pythiosis required enucleation/evisceration. CONCLUSIONS Here, we report, to our knowledge, the largest case study of human pythiosis. The disease has high rates of morbidity and mortality. Early diagnosis and effective treatment are urgently needed to improve clinical outcomes. Because P. insidiosum is distributed worldwide and can infect healthy individuals, an awareness of human pythiosis should be promoted in Thailand and in other countries.

Use of an Immunotherapeutic Vaccine to Treat a Life-Threatening Human Arteritic Infection Caused by Pythium insidiosum

A 14-year-old Thai boy presented because of a history of headache, mandibular swelling, and facial nerve palsy. A microorganism identified as Pythium insidiosum was cultured from the mandibular abscesses. Despite treatment with amphotericin B, iodides, ketoconazole, and surgery, the infection progressed. Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) of the neck revealed an aneurysm in the external carotid artery. The aneurysm was removed. MRA performed later showed stenosis of the internal carotid artery. Immunotherapy was recommended as a last resort. One hundred microliters of the P. insidiosum vaccine was subcutaneously injected into the patients left shoulder, and 14 days later a similar dose was administered. Four weeks following the first vaccination, the patients headache had disappeared, the facial swellings had dramatically diminished, the cervical lymph node had shrunk, and the proximal left internal carotid artery stenosis had significantly improved. One year after the vaccinations, the boy was considered clinically cured.

Infections with rapidly growing mycobacteria: report of 20 cases

OBJECTIVES A series of cases infected with rapidly growing mycobacteria was studied to determine the spectrum of disease, antimicrobial susceptibility, treatment, and outcome. METHODS The cases identified as infections with rapidly growing mycobacteria in Ramathibodi Hospital from January 1993 to December 1999 were retrospectively studied. RESULTS Most of the cases had no underlying disease. Only two cases were HIV-infected patients. The presenting clinical features were lymphadenitis (seven cases), skin and/or subcutaneous abscess (seven cases), localized eye infection (four cases), pulmonary infection (one case), and chronic otitis media (one case). Four of seven cases with lymphadenitis had Sweets syndrome, and one had psoriasis as an associated skin manifestation. Anemia was present in five cases, and improved with treatment of the primary disease. The organisms were Mycobacterium chelonae/abscessus group (17 cases) and Mycobacterium fortuitum group (three cases). Susceptibility patterns of the organisms showed susceptibility to amikacin, netilmicin, and imipenem. M. fortuitum group was susceptible to more antibiotics than M. chelonae/abscessus group. The clinical responses corresponded to the antimicrobial susceptibility. Combinations of two or more drugs were used for the medical treatment. Surgical resection was performed where possible, to reduce the load of the organism, especially in cases with very resistant organisms. CONCLUSIONS Infections with rapidly growing mycobacteria can occur in apparently normal hosts. The clinical syndrome is variable. The pathology is nonspecific. Clinical responses varied, but seemed to correlate with the in vitro susceptibility result. More studies are needed to enable us to deal with this infection effectively.

Development and Evaluation of an In-House Enzyme-Linked Immunosorbent Assay for Early Diagnosis and Monitoring of Human Pythiosis

ABSTRACT Human pythiosis is an emerging, fatal, infectious disease caused by Pythium insidiosum and occurs in both tropical and subtropical countries. Thalassemic patients, farmers, and aquatic-habitat residents are predisposed to this disease. Delayed treatment due to the long time required for isolation and identification of the causative organism, as well as the difficulty in obtaining internal organ specimens, results in high morbidity and mortality. To facilitate rapid diagnosis, an in-house enzyme-linked immunosorbent assay (ELISA) for the detection of immunoglobulin G antibodies against P. insidiosum was developed and evaluated for the diagnosis and monitoring of human pythiosis. Sixteen sera were collected from seven culture-proven human pythiosis cases. A total of 142 sera from thalassemic patients, from patients with other infectious diseases, and from healthy blood donors served as controls. All sera were tested in duplicate. By choosing a suitable cutoff point to maximize sensitivity and specificity, sera from pythiosis cases were all determined to be positive, whereas sera from control groups were all determined to be negative. ELISA signals from serial samples of sera taken from treated patients showed gradually declining levels of antibodies to P. insidiosum. The ELISA test was highly sensitive (100%) and specific (100%) and was useful for early diagnosis and for monitoring the treatment for pythiosis.

Concomitant tuberculous and cryptococcal thyroid abscess in a human immunodeficiency virus-infected patient

Suppurative thyroiditis is a rare condition caused mostly by Staphylococcus aureus and streptococci. Both tuberculous and cryptococcal thyroid abscess are even rarer. The incidence of extrapulmonary forms of tuberculosis and cryptococcosis has increased in areas with a high prevalence of human immunodeficiency virus (HIV) infection. A case is reported of dual infection by M. tuberculosis and Cryptococcus neoformans presenting as a thyroid abscess in a 32-y-old woman with symptomatic HIV infection. Atypical presentations of both tuberculosis and cryptococcosis should be considered in areas with a high incidence of these diseases.

Chronic Diarrhoea Caused by Cryptococcus neoformans in a Non-human Immunodeficiency Virus-infected Patient

A 43-y-old woman with underlying cervix carcinoma stage IIIB, status postirradiation, and diabetes mellitus with tripathy suffered from chronic diarrhoea for more than 6 months. Stool examination showed few white blood cells and red blood cells. Rectal swab cultures disclosed Cryptococcus neoformans in 2 samples obtained 2 weeks apart. The diarrhoea responded to treatment with oral fluconazole for 4 weeks. Repeated rectal swabs revealed no yeast growth. During follow-up for 4 y, she had no problems with diarrhoea. Chronic diarrhoea caused by C. neoformans is rare and clinical suspicion is needed.