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Featured researches published by Douadi Benacer.


Microbes and Environments | 2013

Pathogenic and Saprophytic Leptospira Species in Water and Soils from Selected Urban Sites in Peninsular Malaysia

Douadi Benacer; Pei Yee Woh; Siti Nursheena Mohd Zain; Fairuz Amran; Kwai Lin Thong

Leptospira species were studied in water and soils from selected urban sites in Malaysia. A total of 151 water (n=121) and soil (n=30) samples were collected from 12 recreational lakes and wet markets. All samples were filtered and inoculated into semi-solid Ellinghausen and McCullough modified by Johnson and Harris (EMJH) media supplemented with additional 5-fluorouracil. The cultures were then incubated at 30°C and observed under a dark field microscope with intervals of 10 days. A PCR assay targeting the rrs gene was used to confirm the genus Leptospira among the isolates. Subsequently, the pathogenic status of the isolates was determined using primer sets G1/G2 and Sapro1/Sapro2, which target the secY and rrs genes, respectively. The isolates were identified at serogroup level using the microscopic agglutination test (MAT) while their genetic diversity was assessed by pulsed field gel electrophoresis (PFGE). Based on dark field microscopy, 23.1% (28/121) water and 23.3% (7/30) soil cultures were positive for Leptospira spp. Of the 35 positive cultures, only 8 were pure and confirmed as Leptospira genus by PCR assay. Two out of 8 isolates were confirmed as pathogenic, 5 were saprophytic and one was intermediate. These 8 isolates were negative for the 25 reference hyperimmune rabbit sera tested in the MAT. PFGE showed that all 8 of these environmental Leptospira spp. were genetically diverse. In conclusion, the presence of pathogenic Leptospira spp. in the urban Malaysian environment may indicate and highlight the importance of water screening, especially in recreational lakes, in order to minimize any chance of Leptospira infection.


American Journal of Tropical Medicine and Hygiene | 2013

Isolation and molecular characterization of leptospira interrogans and leptospira borgpetersenii isolates from the urban rat populations of Kuala Lumpur, Malaysia

Douadi Benacer; Siti Nursheena Mohd Zain; Fairuz Amran; Renee L. Galloway; Kwai Lin Thong

Rats are considered the principal maintenance hosts of Leptospira. The objectives of this study were isolation and identification of Leptospira serovars circulating among urban rat populations in Kuala Lumpur. Three hundred urban rats (73% Rattus rattus and 27% R. norvegicus) from three different sites were trapped. Twenty cultures were positive for Leptospira using dark-field microscopy. R. rattus was the dominant carrier (70%). Polymerase chain reaction (PCR) confirmed that all isolates were pathogenic Leptospira species. Two Leptospira serogroups, Javanica and Bataviae, were identified using microscopic agglutination test (MAT). Pulsed-field gel electrophoresis (PFGE) identified two serovars in the urban rat populations: L. borgpetersenii serovar Javanica (85%) and L. interrogans serovar Bataviae (15%). We conclude that these two serovars are the major serovars circulating among the urban rat populations in Kuala Lumpur. Despite the low infection rate reported, the high pathogenicity of these serovars raises concern of public health risks caused by rodent transmission of leptospirosis.


Asia-Pacific Journal of Public Health | 2016

Human Leptospirosis in Malaysia: Reviewing the Challenges After 8 Decades (1925-2012).

Douadi Benacer; Kwai Lin Thong; Khebir Bin Verasahib; Renee L. Galloway; Rudy A. Hartskeerl; J.W. Lewis; Siti Nursheena Mohd Zain

The history and epidemiology of human leptospirosis in Malaysia from 1925 to 2012 are described. Previous studies have demonstrated that leptospirosis is an endemic disease in Malaysia occurring in both urban and rural locations. The number of cases has risen dramatically since the Ministry of Health Malaysia highlighted leptospirosis as a notifiable disease in 2010, with reported cases increasing from 248 cases in 2004 to 3604 in 2012. The incidence of infection among the population suggests that occupation, sex, age, ethnic background, water recreational activities, and sporting events are risk factors. A robust surveillance system is now in place to monitor temporal and spatial changes in the incidence and prevalence of infection and to identify risk areas and disease behavior. Despite extensive studies over the past decade, there is a still a need to describe local serovars in host carriers and the human population, with the view to develop an effective vaccine against leptospirosis.


Acta Tropica | 2016

Epidemiology of human leptospirosis in Malaysia, 2004-2012

Douadi Benacer; Kwai Lin Thong; Ng Choung Min; Khebir Bin Verasahib; Renee L. Galloway; Rudy A. Hartskeerl; Marc Souris; Siti Nursheena Mohd Zain

Leptospirosis is an emerging disease, especially in countries with a tropical climate such as Malaysia. A dramatic increase in the number of cases has been reported over the last decade; however, information on the epidemiological trends of this disease is lacking. The objective of this study is to provide an epidemiological description of human leptospirosis cases over a 9-year period (2004-2012) and disease relationship with meteorological, geographical, and demographical information. A retrospective study was undertaken to describe the patterns of human leptospirosis cases and their association with intrinsic (sex, age, and ethnicity) and extrinsic (location, rainfall, and temperature) factors. Data was grouped according to age, sex, ethnicity, seasonality and geographical distribution, and analyzed using statistical tools to understand the influence of all the different factors on disease incidence. A total of 12,325 cases of leptospirosis were reported between 2004 and 2012 with an upward trend in disease incidence, with the highest in 2012. Three hundred thirty-eight deaths were reported with an overall case fatality rate of 2.74%, with higher incidence in males (9696; 78.7%) compared with female patients (2629; 21.3%), and overall male to female ratio of 3.69:1. Patients aged cohorts between 30-39 years old (16.22 per 100,000 population) had the highest disease incidence while the lowest incidence occurred between <1 to 9 years old (3.44 per 100,000 population). The average incidence was highest amongst Malays (10.97 per 100,000 population), followed by Indians (7.95 per 100,000 population). Stratification according to geographical distribution showed that the state of Malacca had the highest average disease incidence (11.12 per 100,000 population) followed by Pahang (10.08 per 100,000 population). The states of Terengganu, Kelantan, and Perak recorded similar rates of incidence (≈8.00 per 100,000 population), while Johor with the least number of reported cases (1.80 per 100,000 population). Positive relationships were recorded between the number of reported cases with the number of raining days per month and monthly average temperature (p-value<0.05). However, no significant association was noted between rainfall volume and number of reported Leptospirosis cases. This collaborative efforts between medical, academic and governmental institutions has enabled the construction of this comprehensive database that is essential to understand the disease trends in Malaysia and add insights into the prevention and control of this disease.


Indian Journal of Medical Microbiology | 2017

Antimicrobial susceptibility of Leptospira spp. isolated from environmental, human and animal sources in Malaysia

Douadi Benacer; Siti Nursheena Mohd Zain; Peck Toung Ooi; Kwai Lin Thong

Leptospirosis is a zoonosis with worldwide distribution caused by pathogenic spirochetes of the genus Leptospira. The aim of this study was to evaluate the susceptibility of isolates obtained from different hosts. A total of 65 Leptospira isolates from humans (n = 1), zoonoses (rat, n = 60; dog, n = 1; swine, n = 1) and environment (n = 2) were tested against six antibiotics. All the isolates were resistant to trimethoprim and sulphamethoxazole and had high MIC toward chloramphenicol (MIC90: 6.25 μg/ml). All except one environment isolate were sensitive to ampicillin, doxycycline and penicillin G.


Journal of Medical Microbiology | 2016

Predominance of the ST143 and ST50 Leptospira clones in the urban rat populations of Peninsular Malaysia.

Douadi Benacer; Siti Nursheena Mohd Zain; Ahmed Ahmed; Mohd Khairul Nizam Mohd Khalid; Rudy A. Hartskeerl; Kwai Lin Thong

Leptospirosis is a zoonotic and an emerging infectious disease caused by the pathogenic Leptospira species (Levett, 2001). Leptospirosis is transmitted directly or indirectly through urine of infected animals or environments contaminated with urine of reservoir animals (Bharti et al., 2003; Ullmann & Langoi, 2011). Serovar identification of Leptospira isolates constitutes an important component in understanding leptospiral epidemiology and establishment of appropriate control and preventive measures, especially in areas where the disease is prevalent (Bourhy et al., 2013). To date, more than 300 serovars that belong to 29 serogroups have been identified and described (Saito et al., 2013; Bourhy et al., 2014).


Revista Da Sociedade Brasileira De Medicina Tropical | 2017

A duplex endpoint PCR assay for rapid detection and differentiation of Leptospira strains

Douadi Benacer; Siti Nursheena Mohd Zain; J.W. Lewis; Mohd Khairul Nizam Mohd Khalid; Kwai Lin Thong

INTRODUCTION: This study aimed to develop a duplex endpoint PCR assay for rapid detection and differentiation of Leptospira strains. METHODS: Primers were designed to target the rrs (LG1/LG2) and ligB (LP1/LP2) genes to confirm the presence of the Leptospira genus and the pathogenic species, respectively. RESULTS: The assay showed 100% specificity against 17 Leptospira strains with a limit of detection of 23.1pg/µl of leptospiral DNA and sensitivity of 103 leptospires/ml in both spiked urine and water. CONCLUSIONS: Our duplex endpoint PCR assay is suitable for rapid early detection of Leptospira with high sensitivity and specificity.


Journal of Microbiology and Biotechnology | 2010

Characterization of Drug-Resistant Salmonella enterica Serotype Typhimurium by Antibiograms, Plasmids, Integrons, Resistance Genes, and PFGE

Douadi Benacer; Kwai Lin Thong; Haruo Watanabe; Savithri Devi Puthucheary


Parasites & Vectors | 2016

Determination of Leptospira borgpetersenii serovar Javanica and Leptospira interrogans serovar Bataviae as the persistent Leptospira serovars circulating in the urban rat populations in Peninsular Malaysia

Douadi Benacer; Siti Nursheena Mohd Zain; Shin Zhu Sim; Mohd Khairul Nizam Mohd Khalid; Renee L. Galloway; Marc Souris; Kwai Lin Thong


Tropical Biomedicine | 2017

Serological and molecular identification of Leptospira spp.in swine and stray dogs from Malaysia

Douadi Benacer; Kwai Lin Thong; Peck Toung Ooi; Marc Souris; J.W. Lewis; Ahmed Ahmed; S.N. Mohd Zain

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Renee L. Galloway

Centers for Disease Control and Prevention

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Marc Souris

Asian Institute of Technology

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Peck Toung Ooi

Universiti Putra Malaysia

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Ahmed Ahmed

Royal Tropical Institute

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