Frédérique Provost

Human Nocardiosis in Northern Italy from 1982 to 1992

We conducted a retrospective survey of nocardiosis in 9 city hospitals in northern Italy from 1982 to 1992. The medical records of 30 patients with documented nocardiosis were reviewed. Microbiological data included morphology, biochemical characteristics, serology and in vitro susceptibility testing. The 29 isolates (1 case was diagnosed on the basis of serological results) were Nocardia asteroides (n = 25) and Nocardia farcinica (n = 4). Predisposing factors including immunosuppression for organ transplant rejection prophylaxis, lung disease (silicotuberculosis and pulmonary fibrosis), solid tumours and hematological malignancies, and AIDS. Three patients had no identified risk factors. 20 cases of pulmonary nocardiosis were observed. Sites of infection in patients without previous pulmonary involvement were: brain abscesses, soft tissues, pericardium, blood, and cerebrospinal fluid. Most strains tested were susceptible to amikacin and imipenem. Resistance to several antimicrobial agents was found, particularly erythromycin, fosfomycin, pefloxacin, sulphonamides and trimethoprim. Antimicrobial chemotherapy included sulphonamides, amikacin, ceftriaxone, imipenem and minocycline. 21 patients survived, although 2 relapsed transiently. Nocardiosis appears to be more common than generally realised by physicians in northern Italy. The local species distribution and disease spectrum are similar to those described elsewhere. Nocardiosis should be part of the differential diagnosis in patients with pulmonary infiltrates or brain abscess, particularly those with predisposing factors.

Report of human nocardiosis in Italy between 1993 and 1997

During a 5-year period, from 1993 to 1997, nocardial infection was diagnosed in 26 patients admitted to hospitals in 11 cities in Italy. Pathogens were identified as Nocardia asteroides in 18 cases, as N. farcinica in five cases, as N. nova in two and as N. brasiliensis in one case. All cases were difficult to diagnose, as usually it happens with this disease: physicians have to be alert to suspect nocardial infection so that appropriate therapy can be early given. This is the second retrospective report on Nocardia spp. infection conducted in Italy, suggesting the utility to organise a permanent network for a national survey system for nocardiosis.

Nocardia asteroides in the soil of Kuwait.

A pilot study was undertaken to determine the occurrence and distribution of pathogenic nocardiae in Kuwaiti soil. A total of 102 soil samples collected from two localities were investigated by the paraffin bait technique. Nocardia asteroides was the only species isolated from 42 (41%) soil samples. None of the isolates fulfilled the criteria required for identification of N. farcinica or N. nova. Thirty one (73.8%) isolates showed equivalent growth at 45 °C and 35 °C, 17 (40.4%) isolates utilized acetamide for carbon and nitrogen requirements and 3 (7.1%) isolates showed delayed arylsulphatase activity. Only a solitary isolate was resistant to cefamandole. Soil samples originating from the Kuwait University Campus Shuwaikh, which were rich in humus/organic matter, were more productive for N. asteroides (67%) than the samples which were devoid of it but were mixed with crude oil (39%). Sand samples that lacked organic matter and crude oil samples were least productive of N. asteroides. These preliminary findings do not suggest that massive oil contamination of soil in the Ahmadi oil field area during the Gulf war promoted the natural occurrence of N. asteroides. However, isolation of N. asteroides in as many as 41% of the soil sample is a significant observation warranting further epidemiologic studies including its possible role in the operation desert storm sickness syndrome. This is the first report on the natural occurrence of N. asteroides in Kuwait.

Enzymatic characterization of Nocardia spp. and related bacteria by API ZYM profile

Characterization of 62 isolates belonging to the genus Nocardia and related bacteria was obtained by using the API ZYM system. The difference in enzymatic profile should allow a relatively efficient, low-cost means to identify aerobic actinomycetes of clinical significance.

Characterization of Nocardia, Rhodococcus and Gordona Species by in vitro Susceptibility Testing

Representative strains of Gordona, Nocardia and Rhodococcus were tested against 26 antimicrobial agents using the disc diffusion method. A distinct susceptibility profile was noted for most species. Nocardia asteroides, N. brasiliensis, N. otitidiscaviarum, N. transvalensis and N. vaccinii were rarely susceptible to the antibiotics tested; N. brevicatena and N. farcinica varied in their susceptibility depending on the strain tested. Only the antibiotic amikacin was active against all nocardiae. In contrast, the Gordona and Rhodococcus strains showed considerable susceptibility, in particular to the beta-lactam antibiotics. Amoxicillin + clavulanic acid and gentamicin were active against all of the gordonae and rhodococci. The differences in susceptibility patterns may prove useful in characterizing the genera Gordona, Nocardia and Rhodococcus and in separating species within these taxa.

Transmission of nocardiosis and molecular typing of Nocardia species: A short review

Nocardia species are ubiquitous in the environment and may be found in the soil. They are generally responsible for sporadic pulmonary diseases acquired by inhalation of spores, with secondary localizations in the central nervous system and subcutaneous tissues. There is no absolute evidence for person to person transmission. Presumptive outbreaks of nocardiosis were observed in immunocompromised patients, more frequently in kidney transplant patients than in cardiac transplant patients. Nocardia spp., being present in dust particles, closure and disinfection of the transplantation unit with formaldehyde arrested the sequence of cases of nocardiosis. The original sources of the Nocardia sp. remain doubtful. Other possible sources of contamination are other patients, medical staff and the hospital environment. The first studies of Nocardia spp. typing were based on the detection of extracellular antigens, on the susceptibility of actinomycete strains to killer yeasts, and on the biochemical profiles with fluorogenic substrate. The use of molecular typing techniques have given very promising results. Analysis of plasmid profiles is an interesting way to compare the identity of isolates, although the reliability of this method depends of the presence of plasmids in the isolates. Other typing methods, including analysis of restriction length fragment polymorphism of total DNA, ribosomal DNA fingerprinting, require further investigations to evaluate their discriminating power or to be easily interpretable, whereas a random amplified polymorphic DNA (RAPD) assay was successful for epidemiological purposes. Progress in epidemiological analysis of cases of nocardiosis will be consistent when an improved diagnosis of this infection (molecular and serological diagnosis) will be available, when the genetic diversity of Nocardia spp. isolates will be better known, and when molecular typing, that hold promise in complementing investigations of outbreak of these infections, will be systematically performed when an abnormal increase of cases of nocardiosis in a population with risk factors is observed.

A study of the enzymatic profile of soil isolates of Nocardia asteroides.

In this study, using the API-ZYM system, we have reported the enzyme profile of 42 soil strains and 2 clinical strains of Nocardia asteroides isolated locally. Of the 19 enzymes tested, only 7 were demonstrable in over 90% of the soil isolates. These included alkaline phosphatase, esterase lipase, leucine arylamidase, acid phosphatase, phosphohydrolase, α-glucosidase and β-glucosidase. In addition, β-galactosidase activity was demonstrated in all the strains by the O-nitrophenyl-β-D-galactopyranoside (ONPG) test. The enzymes which were not demonstrable in >95% of the strains included valine arylamidase, cystine arylamidase, trypsin, chymotrypsin, α-galactosidase, β-glucoronidase, N-acetyl-β-glucosaminidase, α-mannosidase and α-fucosidase. With the exception of valine arylamidase, which was lacking in all but one isolate, the enzyme profiles of the soil isolates were comparable with the clinical isolates of N. asteroides reported in previous studies. The reasons for this difference in the two sets of isolates is not clear. The study reinforces the view that specific differences in the enzymatic profiles of Nocardia species could be used for their rapid identification. However, more extensive studies are needed to establish the reproducibility of this method. To the best of our knowledge, this is the first study of the enzymatic profile of soil isolates of N. asteroides originating from a single geographic region.

Genetic relatedness analysis of nocardia strains by random amplification polymorphic Dna: validation and applications.

Until now, no simple and rapid technique existed for epidemiological study of strains belonging to the Nocardia genus. The application of the arbitrarily primed PCR procedure to generate randomly amplified polymorphic DNA (RAPD) fingerprints for such analysis of Nocardia isolates was investigated. Fifty-one unrelated clinical isolates of N. asteroides were tested. Two conditions of RAPD using two different primers generated RAPD fingerprints that allowed the differentiation of all strains. The patterns were reproducible and discriminating. The results highlight the diversity of N. asteroides species and confirm that RAPD analysis is a highly valuable tool for studying the epidemiology of the Nocardia genus. Several examples describe the advantage of RAPD analysis for establishing the relationship between isolates from a given patient (long-term infections, coinfections) and from different patients (i.e. during an outbreak). In the future, this technique will help us to investigate the source of infection in cases of nosocomial transmission, to understand the outcome of nocardiosis, and to follow the evolution and acquisition of resistance to Nocardia strains.

Enzyme immunoassay on whole Nocardia asteroides cells for human nocardiosis

Abstract An enzyme immunoassay is presented here for the rapid diagnosis of nocardiosis with whole Nocardia asteroides cells adsorbed on microtitration plates. Sera from 15 subjects infected with N. asteroides (five non-immunosuppressed patients and 10 patients under immunosuppressive therapy) and six patients with mycetoma due to N. brasiliensis were tested. Controls included sera from six patients with a mycetoma due to Actinomadura madurae or Rhodococcus rhodochrous, 13 patients with leprosy or tuberculosis, and seven uninfected normal individuals. Five of the non-immunosuppressed patients with nocardiosis were determined as positive (100% of sensitivity). None of the immunosuppressed cases of nocardiosis were positive. No crossreactions were observed with serum of patients with mycetoma due to N. brasiliensis or A. madurae. Some false-positive reactions were found in patients with leprosy, tuberculosis, or a mycetoma due to R. rhodochrous.