Pierre Edouard Fournier

The Epidemiology and Control of Acinetobacter baumannii in Health Care Facilities

Acinetobacter baumannii is a ubiquitous pathogen capable of causing both community and health care-associated infections (HAIs), although HAIs are the most common form. This organism has emerged recently as a major cause of HAI because of the extent of its antimicrobial resistance and its propensity to cause large, often multifacility, nosocomial outbreaks. The occurrence of outbreak is facilitated by both tolerance to desiccation and multidrug resistance, contributing to the maintenance of these organisms in the hospital environment. In addition, the epidemiology of A. baumannii infection is often complex, with the coexistence of epidemic and endemic infections, the latter of which often is favored by the selection pressure of antimicrobials. The only good news is that potentially severe A. baumannii infection, such as bacteremia or pneumonia in patients in the intensive care unit who are undergoing intubation, do not seem to be associated with a higher attributable mortality rate or an increased length of hospital stay.

Q fever 1985-1998. Clinical and epidemiologic features of 1,383 infections.

In order to describe the clinical features and the epidemiologic findings of 1,383 patients hospitalized in France for acute or chronic Q fever, we conducted a retrospective analysis based on 74,702 sera tested in our diagnostic center, National Reference Center and World Health Organization Collaborative Center for Rickettsial Diseases. The physicians in charge of all patients with evidence of acute Q fever (seroconversion and/or presence of IgM) or chronic Q fever (prolonged disease and/or IgG antibody titer to phase I of Coxiella burnetii > or = 800) were asked to complete a questionnaire, which was computerized. A total of 1,070 cases of acute Q fever was recorded. Males were more frequently diagnosed, and most cases were identified in the spring. Cases were observed more frequently in patients between the ages of 30 and 69 years. We classified patients according to the different clinical forms of acute Q fever, hepatitis (40%), pneumonia and hepatitis (20%), pneumonia (17%), isolated fever (17%), meningoencephalitis (1%), myocarditis (1%), pericarditis (1%), and meningitis (0.7%). We showed for the first time, to our knowledge, that different clinical forms of acute Q fever are associated with significantly different patient status. Hepatitis occurred in younger patients, pneumonia in older and more immunocompromised patients, and isolated fever was more common in female patients. Risk factors were not specifically associated with a clinical form except meningoencephalitis and contact with animals. The prognosis was usually good except for those with myocarditis or meningoencephalitis as 13 patients died who were significantly older than others. For chronic Q fever, antibody titers to C. burnetii phase I above 800 and IgA above 50 were predictive in 94% of cases. Among 313 patients with chronic Q fever, 259 had endocarditis, mainly patients with previous valvulopathy; 25 had an infection of vascular aneurysm or prosthesis. Patients with endocarditis or vascular infection were more frequently immunocompromised and older than those with acute Q fever. Fifteen women were infected during pregnancy; they were significantly more exposed to animals and gave birth to only 5 babies, only 2 with a normal birth weight. More rare manifestations observed were chronic hepatitis (8 cases), osteoarticular infection (7 cases), and chronic pericarditis (3 cases). Nineteen patients were observed who experienced first a documented acute infection, then, due to underlying conditions, a chronic infection. To our knowledge, we report the largest series of Q fever to date. Our results indicate that Q fever is a protean disease, grossly underestimated, with some of the clinical manifestations being only recently reported, such as Q fever during pregnancy, chronic vascular infection, osteomyelitis, pericarditis, and myocarditis. Our data confirm that chronic Q fever is mainly determined by host factors and demonstrate for the first time that host factors may also play a role in the clinical expression of acute Q fever.

Cultivation of the bacillus of Whipple's disease

BACKGROUND Whipples disease is a systemic bacterial infection, but to date no isolate of the bacterium has been established in subculture, and no strain of this bacterium has been available for study. METHODS Using specimens from the aortic [corrected] valve of a patient with endocarditis due to Whipples disease, we isolated and propagated a bacterium by inoculation in a human fibroblast cell line (HEL) with the use of a shell-vial assay. We tested serum samples from our patient, other patients with Whipples disease, and control subjects for the presence of antibodies to this bacterium. RESULTS The bacterium of Whipples disease was grown successfully in HEL cells, and we established subcultures of the isolate. Indirect immunofluorescence assays showed that the patients serum reacted specifically against the bacterium. Seven of 9 serum samples from patients with Whipples disease had IgM antibody titers of 1:50 or more, as compared with 3 of 40 samples from the control subjects (P<0.001). Polyclonal antibodies against the bacterium were generated by inoculation of the microorganism into mice and were used to detect bacteria in the excised cardiac tissue from our patient on immunohistochemical analysis. The 16S ribosomal RNA gene of the cultured bacterium was identical to the sequence for Tropheryma whippelii identified previously in tissue samples from patients with Whipples disease. The strain we have grown is available in the French National Collection. CONCLUSIONS We cultivated the bacterium of Whipples disease, detected specific antibodies in tissue from the source patient, and generated specific antibodies in mice to be used in the immunodetection of the microorganism in tissues. The development of a serologic test for Whipples disease may now be possible.

RICKETTSIA AFRICAE, A TICK-BORNE PATHOGEN IN TRAVELERS TO SUB-SAHARAN AFRICA

BACKGROUND African tick-bite fever occurs after contact with ticks that carry Rickettsia africae and that parasitize cattle and game. Sporadic reports suggest that this infection has specific clinical and epidemiologic features. METHODS We studied patients who were tested for a rickettsial disease after returning from a visit to Africa or Guadeloupe. To assess the value of the microimmunofluorescence assay, Western blotting, and cross-adsorption assays, we compared the results of these tests in 39 patients in whom African tick-bite fever had been confirmed by the polymerase-chain reaction assay, cell culture, or both; 50 patients with documented R. conorii infection; and 50 blood donors. These diagnostic criteria were then applied to 376 additional patients who had returned from southern Africa and 2 who had returned from Guadeloupe and whose serum was being tested for rickettsial disease. RESULTS In the 39 patients with direct evidence of R. africae infection, the combination of microimmunofluorescence assay, Western blotting, and cross-adsorption assays showing antibodies specific for R. africae had a sensitivity of 0.56; however, each test had a positive predictive value and a specificity of 1.0. An additional 80 patients were found to have an R. africae infection on the basis of these serologic criteria. Infections with R. africae were acquired by visitors to 11 African countries and Guadeloupe. The illness was generally mild and was characterized by a rash in 46 percent of the patients; the rash was usually maculopapular or vesicular and rarely purpuric. Ninety-five percent of patients had an inoculation eschar or eschars, and 54 percent of these patients had multiple eschars, a finding that is unusual in patients with rickettsial infection. CONCLUSIONS In this series, R. africae was the cause of nearly all cases of tick-bite rickettsiosis in patients who became ill after a trip to sub-Saharan Africa.

MALDI-TOF-mass spectrometry applications in clinical microbiology

MALDI-TOF-mass spectrometry (MS) has been successfully adapted for the routine identification of microorganisms in clinical microbiology laboratories in the past 10 years. This revolutionary technique allows for easier and faster diagnosis of human pathogens than conventional phenotypic and molecular identification methods, with unquestionable reliability and cost-effectiveness. This article will review the application of MALDI-TOF-MS tools in routine clinical diagnosis, including the identification of bacteria at the species, subspecies, strain and lineage levels, and the identification of bacterial toxins and antibiotic-resistance type. We will also discuss the application of MALDI-TOF-MS tools in the identification of Archaea, eukaryotes and viruses. Pathogenic identification from colony-cultured, blood-cultured, urine and environmental samples is also reviewed.

Spotless Rickettsiosis Caused by Rickettsia slovaca and Associated with Dermacentor Ticks

The pathogenic role of Rickettsia slovaca was first demonstrated in 1997 in a patient who presented with a single inoculation lesion of the scalp and enlarged cervical lymph nodes after receiving a bite from a Dermacentor tick. Subsequently, we evaluated the occurrence of R. slovaca infections among patients living in France and Hungary who presented with these symptoms. R. slovaca infections were confirmed by polymerase chain reaction (PCR) in 17 of 67 enrolled patients. Infections were most likely to occur in patients aged <10 years and in patients who were bitten during the colder months of the year. The median duration of incubation for the disease was 7 days. Fever was present in only 2 patients, and only 1 patient developed a rash. Sequelae included persistent asthenia (3 cases) and localized alopecia (4 cases). Immunofluorescence and/or Western blot analysis detected antibodies in 50% of tested patients. Three Dermacentor ticks obtained from patients revealed R. slovaca by PCR.

What does the future hold for clinical microbiology

In the past decade, clinical microbiology laboratories have undergone important changes with the introduction of molecular biology techniques and laboratory automation. In the future, there will be a need for more rapid diagnoses, increased standardization of testing and greater adaptability to cope with new threats from infectious microorganisms, such as agents of bioterrorism and emerging pathogens. The combination of the new tools that are now being developed in research laboratories, the general reorganization of clinical laboratories and improved communication between physicians and clinical microbiologists should lead to profound changes in the way that clinical microbiologists work.

Genotyping reveals a wide heterogeneity of Tropheryma whipplei.

Tropheryma whipplei, the causative agent of Whipples disease, is associated with various clinical manifestations as well as an asymptomatic carrier status, and it exhibits genetic heterogeneity. However, relationships that may exist between environmental and clinical strains are unknown. Herein, we developed an efficient genotyping system based on four highly variable genomic sequences (HVGSs) selected on the basis of genome comparison. We analysed 39 samples from 39 patients with Whipples disease and 10 samples from 10 asymptomatic carriers. Twenty-six classic gastrointestinal Whipples disease associated with additional manifestations, six relapses of classic Whipples disease (three gastrointestinal and three neurological relapses), and seven isolated infections due to T. whipplei without digestive involvement (five endocarditis, one spondylodiscitis and one neurological infection) were included in the study. We identified 24 HVGS genotypes among 39 T. whipplei DNA samples from the patients and 10 T. whipplei DNA samples from the asymptomatic carriers. No significant correlation between HVGS genotypes and clinical manifestations of Whipples disease, or asymptomatic carriers, was found for the 49 samples tested. Our observations revealed a high genetic diversity of T. whipplei strains that is apparently independent of geographical distribution and unrelated to bacterial pathogenicity. Genotyping in Whipples disease may, however, be useful in epidemiological studies.

Nosocomial Infections Caused by Acinetobacter baumannii A Major Threat Worldwide

From the Unite des Rickettsies, Faculte de Medecine, Universite de la Mediterranee, Marseille, France (both authors). Received May 15, 2006; accepted May 15, 2006; electronically published June 23, 2006. Infect Control Hosp Epidemiol 2006; 27:645-646 2006 by The Society for Healthcare Epidemiology of America. All rights reserved. 0899-823X/2006/2707-0001

Genotyping of Human Lice Suggests Multiple Emergences of Body Lice from Local Head Louse Populations

15.00. Currently, Acinetobacter baumannii is considered to be an important and emerging hospital-acquired pathogen worldwide. It is responsible for 2%-10% of all gram-negative bacterial infections in intensive care units in Europe and the United States. However, despite the importance of this organism as a public health problem, several shadow areas persist regarding its virulence, antimicrobial resistance, reservoirs, and epidemiology. Several articles published in this issue of ICHE shed some light on this fascinating bacterium. Some of the uncertainties surrounding A. baumannii are related to the fact that bacteria classified as members of the genus Acinetobacter have a long history of taxonomic changes, moving from the family Neisseriaceae to the family Moraxellaceae. Within the genus Acinetobacter, studies based on DNA-DNA hybridization have described 25 “genomic species” that fulfilled the criteria to be considered as distinct species, and 17 of these have officially been validated to date. This situation has led contributors to the Manual of Clinical Microbiology to state that the majority of the genomic species cannot be reliably distinguished by phenotypic tests. Despite that, and because of the difficulties in differentiating the isolates according to their phenotypic characteristics, the term Acinetobacter calcoaceticus–Acinetobacter baumannii complex is often used. It is important to note, and this may be a limitation of the studies we comment on in this editorial, that in 3 of the 4 studies, species identification was performed using phenotypic methods only, and the isolates were named either A. baumannii or A. baumannii-calcoaceticus. In the study in this issue of the journal by Griffith et al., ribotyping, which could have been used to identify the isolates, was used to compare the isolates but not to identify them, and the isolates were also classified as A. baumanniicalcoaceticus. One of the main concerns about A. baumannii is a characteristic that makes it a major threat to public health, namely, its remarkable ability to rapidly develop antibiotic resistance, mostly by acquisition of gene clusters carried by plasmids, transposons, or integrons, sometimes arranged in resistance islands within the genome. This phenomenon led to multidrug resistance in this species within a few decades. With the emergence of increasingly resistant strains, the management of A. baumannii infection has become a public health problem in many countries. To date, some strains of A. baumannii have become resistant to almost all currently available antibacterial agents, including carbapenems, which were once considered the drug of choice for treatment of A. baumannii infection. In this issue, Peleg et al. describe the frightening emergence of carbapenem resistance in A. baumannii isolates over a 3-year period in an Australian hospital, significantly linked to an increased used of meropenem. They demonstrated, by pulsed-field gel electrophoresis, the clonal origin of these multidrug-resistant strains, but they failed to identify the mechanism associated with carbapenem resistance. The latter point is of particular interest, because Peleg et al. screened strains for the presence of the genes for carbapenemhydrolyzing b-lactamases most commonly found in other countries. However, although Peleg et al. suggested that there may be a nonenzymatic mechanism of resistance or a new b-lactamase, they did not search all currently described genes coding for carbapenem-hydrolyzing b-lactamases. The identification of the mechanism involved in carbapenem resistance in this clonal population of A. baumannii should warrant further investigation to determine whether the bacterium has acquired a resistance gene that is spreading around the world or a gene “made in Australia.” Finally, this article by Peleg et al. emphasizes the risk of misuse of antibiotics, because of the extremely rapid emergence of antibiotic resistance in A. baumannii, and the consequent need for strict rules for prescription of carbapenems. In addition to its propensity to acquire antibiotic resistance, A. baumannii is feared for its ability to cause outbreaks of disease in healthcare facilities. Such outbreaks may take particular forms, such as those that involve multiple facilities. In France, the AYE strain, which produces an extended-spectrum b-lactamase, spread throughout 54 healthcare facilities in 8 administrative regions during an 11-month period. In their study, Fillaux et al. used pulsed-field gel electrophoresis to compare 1,277 A. baumannii strains, including 148 mul-