François Chapuis

Waterborne Outbreak of Intestinal Microsporidiosis in Persons with and without Human Immunodeficiency Virus Infection

Among 1454 persons whose stool samples (n=5692) were submitted to a reference laboratory for microsporidia assessment from 1993 to 1996, microsporidia were identified in 338 persons: 261 persons infected with human immunodeficiency virus (HIV), 16 transplant patients, and 61 others. Intestinal microsporidiosis appears to be an endemic disease in HIV-positive persons (prevalence, 0.1%) and a sporadic disease in HIV-negative persons (prevalence, <1/1 million). A waterborne outbreak in 200 persons (attack rate, 1% in HIV-positive patients/month) occurred in the 1995 summer, without evidence of fecal contamination of water. No explanation was found before the outbreak ended, several months before the antiprotease era. Factors associated with microsporidiosis diagnosis were HIV infection, male homosexuality, low CD4 cell counts, and diarrhea. The major factor associated with a diagnosis of microsporidiosis during the outbreak was living in an area corresponding to one of the three water distribution subsystems of the town. Lake contamination was suspected.

Genetic Polymorphism of Aspergillus fumigatus in Clinical Samples from Patients with Invasive Aspergillosis: Investigation Using Multiple Typing Methods

ABSTRACT The genotypes of 52 strains of Aspergillus fumigatusisolated from 12 patients with invasive aspergillosis were investigated using three typing methods (random amplified polymorphic DNA, sequence-specific DNA polymorphism, and microsatellite polymorphism) combined with multilocus enzyme electrophoresis. Isolates were from patients hospitalized in three different geographic areas (Lyon, France; Grenoble, France; and Milan, Italy). In each case, the genetic polymorphism of several colonies (two to five) within the first respiratory clinical sample was studied. For the 52 isolates tested, random amplified polymorphic DNA identified 8 different genotypes, sequence-specific DNA polymorphism identified 9 different types, and microsatellite polymorphism identified 14 types. A combination of these results with multilocus enzyme electrophoresis study identified 25 different types within the sample studied. We identified 3 patients (of the 12 studied) who carried a single genotype; 6 patients were infected by two genotypes, 1 patient had four genotypes, while the last patient had five. A combination of typing methods provided better discrimination than the use of a single method. Typing methods revealed a population structure within each geographical site, suggesting that the epidemiology of A. fumigatus should be considered separately for each of these geographic areas. This study demonstrates the usefulness of combining several typing methods in reaching an understanding of the epidemiology of A. fumigatus and clarifies whether it is sufficient to type one isolate from each specimen to determine the strain involved in invasive aspergillosis.

Combination of three typing methods for the molecular epidemiology of Aspergillus fumigatus infections

This study investigated the source of infection and strain relatedness of Aspergillus fumigatus isolates from bronchial colonisation and invasive aspergillosis (IA) in four transplant patients. Environmental isolates from the patients home and from the hospital and infecting isolates were obtained for patient A who developed IA. Clinic environmental and colonising isolates were obtained for patient B. Sequential isolates were obtained from various organs from patient C who developed IA and also from patient D who had a bronchitic aspergillosis that developed into IA. Ninety-one A. fumigatus isolates were analysed by three typing methods: multi-locus enzyme electrophoresis (MLEE), random amplified polymorphic DNA (RAPD) and sequence-specific DNA primers (SSDP). The three combined typing methods demonstrated a greater differentiation of isolates than the typing methods used separately or in pairs. This demonstrated the genotypic variability of A. fumigatus and facilitated better epidemiological analysis. Large polymorphisms were demonstrated for each patient isolate between and colonies within various samples. The relatedness of the isolates suggested nosocomially acquired aspergillosis for patient B, but the source of infection for patient A remained unclear. The results suggested at least three multiple infections among the four patients. This study enabled the identification of the source of infection and strain relatedness, which in turn facilitates the development of preventive measures for patient management in the future.

A longitudinal study of lung transplant recipients infected with Aspergillus: genetic polymorphism of A fumigatus

BACKGROUND Aspergillus infection is a well-known complication of lung transplantation and remains associated with high mortality rates. Molecular typing methods are required to elucidate the complex epidemiology of Aspergillus disease in lung transplant recipients. METHODS Eight lung transplant recipients from one hospital were followed for A fumigatus colonization or infection. Forty-four sequential isolates from these patients were selected and typed by three molecular methods (random amplified polymorphic DNA, sequence-specific DNA primer and multi-locus enzyme electrophoresis). RESULTS Sixteen different types were identified of which 14 were specific to 1 patient. A factorial correspondence analysis showed that variability between sequential isolates from a single patient was as high as between isolates from the other patients. Lung transplant recipients presented many different genotypes, reflecting the environmental diversity of A fumigatus. Nevertheless, throughout their follow-up, 2 of the 8 lung transplant recipients harbored a common genotype that was not replaced by others. CONCLUSIONS These results confirm the important genetic polymorphism of the A fumigatus population. The observed genotypes were not related to the type of Aspergillus disease or anti-fungal treatment used nor to the outcome of the patient. These data confirm that all A fumigatus molecular types present the same pathogenic risk.

Clinical screening for ulnar nerve damage in leprosy patients

Sirs: The ultimate goal of leprosy programmes across the world is to prevent impairment, disability and deformity. This goal can be achieved by stopping the spread of the disease through early identification of patients, careful screening of nerve damage and prompt treatment with steroids or multi-drug therapy. If patients are identified when their neurological handicap is still reversible [1, 2], effective treatment for nerve damage is available to them. Therefore the diagnosis of early, reversible nerve impairment is of utmost importance. Operational screening should rely on simple, cheap and easily understandable clinical sensory tests because they are usually carried out by health workers after only a few hours’ training. Although many tests for evaluating hands and feet sensitivity have been described, none has so far been accepted as the gold standard. The aim of this prospective study was to assess the diagnostic value of four clinical tests used at the Dakar Leprosy Institute. We focused on ulnar nerve sensitivity because it is accepted that sensory abnormalities appear before weakness, and that ulnar nerve is the first to be involved in the upper extremities [3]. The patient group consisted of 70 patients (138 ulnar nerves) recently diagnosed as leprosy sufferers according to the Ridley and Jopling criteria [4]. The test battery consisted of two nylon threads bent on the skin at a pressure of 0.5 and 0.2 g (based on the Semmes-Weinstein monofilaments testing technique) [5], a pin and a drop of ether. After a preliminary test the patient was blindfolded, and the selected area was tested (Fig. 1). These tests have proven to be normal in 40 healthy subjects examined at the same place under the same conditions as the patients. Clinical tests were then compared to sensory nerve conduction values of the same nerve. Conduction velocities and/or amplitude values were abnormal in 55% of the nerves from the patients. The diagnostic value of the clinical tests is shown in Table 1. Appreciation of the nylon 0.2 g was found to be the most appropriate tool to detect ulnar nerve damage of patients with leprosy. Other studies have showed that results with the Semmes-Weinstein monofilaments are more reproducible than those with the pin prick test [6] with the added advantage of there being no risk of infection from perforating injury. More sensitive measures of thermal sensation (rather than a drop of ether) are not feasible under field conditions [7]. Results were similar between the lepromatous (LL and BL) and tuberculoid (TT and BT) leprosy patients [4]. Other results were tested in a sensitivity analysis: the two most sensitive tests ranked the same. For early detection of nerve damage, test sensitivity is of paramount importance. Hence we conclude that 0.2 g nylon is a useful screening test for nerve damage in leprosy sufferers’ hands, especially in field condition in the developing countries.