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Featured researches published by Aba Mahamat.


Clinical Infectious Diseases | 2012

Q Fever Pneumonia in French Guiana: Prevalence, Risk Factors, and Prognostic Score

Loïc Epelboin; Cédric Chesnais; Charlotte Boullé; Anne-Sophie Drogoul; Didier Raoult; Félix Djossou; Aba Mahamat

BACKGROUND Community-acquired pneumonia (CAP) is the major manifestation of Q fever, an emerging disease in French Guiana. Consequently, the empirical antibiotherapy used for the treatment of CAP combines doxycycline and the recommended amoxicillin. Our objectives were to estimate the prevalence of Q fever pneumonia and to build a prediction rule to identify patients with Q fever pneumonia for empirical antibiotic guidance. METHODS A retrospective case-control study was conducted on inpatients admitted with CAP in the Department of Infectious Diseases of Cayenne Hospital from 2004 to 2007. Serodiagnosis for Coxiella burnetii was performed for all patients. Risk factor analysis was performed using multivariate logistic regression, and a prognostic score was computed using bootstrap procedures. The score performance characteristics were used to choose the best prediction rule to identify patients with Q fever pneumonia. RESULTS One hundred thirty-one patients with CAP were included and the Q fever pneumonia prevalence was 24.4% (95% confidence interval [CI], 17.1-31.9). In multivariate analysis, male sex, middle age (age, 30-60 years), headache, leukocyte count <10 × 10(9)/L and C-reactive protein level >185 mg/L were independently associated with Q fever pneumonia. Patients with a predictive score ≤3 had a low risk of Q fever pneumonia with a negative predictive value of 0.97 (95% CI, .90-1) and a sensitivity of 0.97 (95% CI, .89-1). CONCLUSIONS The prediction rule described here accurately identifies patients with low risk of Q fever pneumonia and may help physicians to make more rational decisions about the empirical use of antibiotherapy. Further prospective studies should be performed to validate this score.


Emerging Infectious Diseases | 2013

Unique Clone of Coxiella burnetii Causing Severe Q Fever, French Guiana

Aba Mahamat; Sophie Edouard; Magalie Demar; Philippe Abboud; Jean-Yves Patrice; Bernard La Scola; Antoine Okandze; Félix Djossou; Didier Raoult

Acute Q fever is an emergent and severe disease in French Guiana. We obtained 5 Coxiella burnetii isolates from samples of patients from Cayenne and found an epidemic clone circulating in Cayenne. This clone has caused pneumonia and endocarditis and seems to be more virulent than previously described strains.


American Journal of Tropical Medicine and Hygiene | 2014

Comparison between Emerging Q Fever in French Guiana and Endemic Q fever in Marseille, France

Sophie Edouard; Aba Mahamat; Magalie Demar; Philippe Abboud; Félix Djossou; Didier Raoult

Q fever is an emergent disease in French Guiana. We compared the incidence clinical and serologic profiles between patients from Cayenne, French Guiana and Marseille in metropolitan France during a four-year period. The annual incidence of diagnosed acute Q fever was significantly higher in Cayenne (17.5/100,000) than in Marseille (1.9/100,000) (P = 0.0004), but not the annual incidence of endocarditis (1.29 versus 0.34/100,000). Most patients had fever (97%) and pneumonia (83%) in Cayenne versus 81% and 8% in Marseille (P < 0.0001 and P < 0.0001, respectively) but transaminitis was more common in patients from Marseille (54% versus 32%; P < 0.0001). The proportion of patients with cardiovascular infections was significantly lower in Cayenne (7%) than in Marseille (17%) (P = 0.017), although they showed a stronger immune response with higher levels of phase I IgG (P = 0.024). The differing epidemiology, clinical, and serologic responses of patients from Cayenne and Marseille suggest a different source of infection and a different strain of Coxiella burnetii.


American Journal of Tropical Medicine and Hygiene | 2014

Q Fever in French Guiana

Carole Eldin; Aba Mahamat; Magalie Demar; Philippe Abboud; Félix Djossou; Didier Raoult

Coxiella burnetii, the causative agent of Q fever, is present worldwide. Recent studies have shown that this bacterium is an emerging pathogen in French Guiana and has a high prevalence (24% of community-acquired pneumonia). In this review, we focus on the peculiar epidemiology of Q fever in French Guiana. We place it in the context of the epidemiology of the disease in the surrounding countries of South America. We also review the clinical features of Q fever in this region, which has severe initial presentation but low mortality rates. These characteristics seem to be linked to a unique genotype (genotype 17). Finally, we discuss the issue of the animal reservoir of C. burnetii in French Guiana, which is still unknown. Further studies are necessary to identify this reservoir. Identification of this reservoir will improve the understanding of the Q fever epidemic in French Guiana and will provide new tools to control this public health problem.


PLOS Neglected Tropical Diseases | 2012

First human rabies case in French Guiana, 2008: epidemiological investigation and control.

Jean-Baptiste Meynard; Claude Flamand; Céline Dupuy; Aba Mahamat; Françoise Eltges; Frederic Queuche; Julien Renner; Jean-Michel Fontanella; Didier Hommel; Philippe Dussart; Claire Grangier; Félix Djossou; Laurent Dacheux; Maryvonne Goudal; Franck Berger; Vanessa Ardillon; Nicolas Krieger; Hervé Bourhy; André Spiegel

Background Until 2008, human rabies had never been reported in French Guiana. On 28 May 2008, the French National Reference Center for Rabies (Institut Pasteur, Paris) confirmed the rabies diagnosis, based on hemi-nested polymerase chain reaction on skin biopsy and saliva specimens from a Guianan, who had never travelled overseas and died in Cayenne after presenting clinically typical meningoencephalitis. Methodology/Principal Findings Molecular typing of the virus identified a Lyssavirus (Rabies virus species), closely related to those circulating in hematophagous bats (mainly Desmodus rotundus) in Latin America. A multidisciplinary Crisis Unit was activated. Its objectives were to implement an epidemiological investigation and a veterinary survey, to provide control measures and establish a communications program. The origin of the contamination was not formally established, but was probably linked to a bat bite based on the virus type isolated. After confirming exposure of 90 persons, they were vaccinated against rabies: 42 from the cases entourage and 48 healthcare workers. To handle that emergence and the local populations increased demand to be vaccinated, a specific communications program was established using several media: television, newspaper, radio. Conclusion/Significance This episode, occurring in the context of a Department far from continental France, strongly affected the local population, healthcare workers and authorities, and the management team faced intense pressure. This observation confirms that the risk of contracting rabies in French Guiana is real, with consequences for population educational program, control measures, medical diagnosis and post-exposure prophylaxis.


American Journal of Tropical Medicine and Hygiene | 2010

High prevalence of HBsAg during pregnancy in Asian communities at Cayenne Hospital, French Guiana.

Aba Mahamat; Dominique Louvel; Tania Vaz; Magalie Demar; Mathieu Nacher; Félix Djossou

We described hepatitis B surface antigen (HBsAg) prevalence among 2,347 pregnant women having delivered at the Cayenne hospital in 2007 according to ethnicity. With 11.0% HBsAg prevalence, Asian women (Hmong and Chinese) were the group with the highest risk of hepatitis B virus (HBV) perinatal transmission compared with other ethnic groups.


American Journal of Infection Control | 2012

Risk of rabies transmission and adverse effects of postexposure prophylaxis in health care workers exposed to a fatal case of human rabies.

Aba Mahamat; Jean-Baptiste Meynard; Félix Djossou; Philippe Dussart; Magalie Demar; Jean-Michel Fontanella; Didier Hommel; Claude Flamand; Hervé Bourhy; André Spiegel

On May 27, 2008, a patient died from rabies at the Cayenne Hospital in French Guiana. Postexposure prophylaxis vaccination was implemented for all health care workers exposed to this patient. Examining the management of such a rare risk reveals important factors in the education of personnel who may have contact with a patient with rabies, to permit appropriate risk assessment and reduce unnecessary postexposure prophylaxis, taking into account the risks and costs of adverse events.


AIDS | 2007

Increased incidence of cutaneous mycoses after HAART initiation: a benign form of immune reconstitution disease?

Mathieu Nacher; Vincent Vantilcke; Aba Mahamat; Myriam El Guedj; Tania Vaz; Andry Randrianjohany; E. Clyti; Christine Aznar; Bernard Carme; Pierre Couppié

Immune reconstitution disease (IRD) has been associated with many pathogens after the initiation of antiretroviral therapy for advanced HIV infection. A retrospective cohort study was conducted to determine whether cutaneous mycoses were also associated with IRD. After adjusting for various confounding factors, the recent initiation of HAART was found to be associated with an increased incidence of cutaneous mycoses when compared with untreated patients.


International Journal of Antimicrobial Agents | 2016

Clinical epidemiology and resistance mechanisms of carbapenem-resistant Acinetobacter baumannii, French Guiana, 2008–2014

Aba Mahamat; Xavier Bertrand; Brigitte Moreau; Didier Hommel; Pierre Couppié; Christine Simonnet; Hatem Kallel; Magalie Demar; Félix Djossou; Mathieu Nacher

This study investigated the clinical epidemiology and resistance mechanisms of Acinetobacter baumannii and characterised the clonal diversity of carbapenem-resistant A. baumannii (CRAB) during an ICU-associated outbreak at Cayenne Hospital, French Guiana. All non-duplicate A. baumannii isolates from 2008 to 2014 were tested for antibiotic susceptibility by disk diffusion. Multilocus sequence typing, pulsed-field gel electrophoresis (PFGE) and characterisation of carbapenemase-encoding genes were performed on CRAB. Of the 441 A. baumannii isolates, most were from males (54.0%) and were detected mainly from the ICU (30.8%) and medicine wards (21.8%). In the ICU, strains were mainly isolated from the respiratory tract (44.1%) and bloodstream (14.0%), whereas in medicine wards they mainly were from wound/drainage (36.5%) and bloodstream (25.0%). A. baumannii showed the greatest susceptibility to piperacillin/tazobactam (92.7%), imipenem (92.5%), colistin (95.6%) and amikacin (97.2%), being lower in the ICU and medicine wards compared with other wards. An outbreak of OXA-23-producing CRAB occurred in the 13-bed ICU in 2010. CRAB strains were more co-resistant to other antimicrobials compared with non-CRAB. Molecular genetics analysis revealed five sequence types [ST78, ST107 and ST642 and two new STs (ST830 and ST831)]. Analysis of PFGE profiles indicated cross-transmissions of CRAB within the ICU, between the ICU and one medicine ward during transfer of patients, and within that medicine ward. This study provides the first clinical and molecular data of A. baumannii from French Guiana and the Amazon basin. The ICU was the highest risk unit of this nosocomial outbreak of OXA-23-producing CRAB, which could subsequently disseminate within the hospital.


American Journal of Tropical Medicine and Hygiene | 2015

Rainfall and Sloth Births in May, Q Fever in July, Cayenne, French Guiana

Carole Eldin; Aba Mahamat; Félix Djossou; Didier Raoult

Q fever in French Guiana is correlated with the rainy season. We found a 1- to 2-month lagged correlation between Q fever incidence and the number of births of three-toed sloth. This result strengthens the hypothesis that the three-toed sloth is the wild reservoir of Q fever in French Guiana.

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Félix Djossou

Aix-Marseille University

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Magalie Demar

University of French Guiana

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Didier Raoult

Aix-Marseille University

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Sophie Edouard

Aix-Marseille University

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Carole Eldin

Aix-Marseille University

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Emilie Mosnier

University of French Guiana

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Félix Djossou

Aix-Marseille University

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