Multilocus variable number tandem repeat analysis for Salmonella enterica subspecies.

Genomic analysis of Salmonella enterica revealed the existence of a variable number of tandem repeats (VNTR) at multiple loci. Some S. enterica strains are considered as references (Typhi Ty2, Typhi CT18, Typhimurium LT2, Enteritidis LK5, PT4, and Enteritidis 07-2642, and Newport). These allowed the selection of markers to develop the genotyping technique, multiple-locus VNTR analysis (MLVA). These markers were used to discriminate S. enterica isolated from humans, food, or the environment. In this report, the characteristics and specifications of 58 salmonella markers described from 2003 to 2009 are analyzed. Some VNTR loci were used as markers. The markers were used to discriminate S. enterica isolates from different sources and geographical localizations. Among the VNTR loci described in the published reports, eight presented with a high diversity index (DI) of polymorphism of more than 0.80. The selection of several markers within a single locus validated their polymorphism characteristic. Despite unequal DI values, the use of a panel of markers is a powerful discriminatory tool for the surveillance and identification of the source of salmonella outbreak. Depending on the markers selected, MLVA should be used either for macro- or microepidemiological purposes. The main challenge in the future for this technique is standardization.

[Asia: avian influenza H5N1]. / La grippe H5N1.

The emergence of the first human cases of avian influenza in Hong Kong in 1997 has raised fears of a new pandemic originating from the Asian continent. Despite unprecedented international mobilization, first to stop then to limit its diffusion, the highly pathogenic avian virus A/H5N1 has successfully spread in Asia, Europe and Africa by successive epizootic outbreaks affecting migratory birds and poultry, Transmission from animals to humans is uncommon but severe with a fatality rate exceeding 60% in confirmed cases. Nearly half of the countries struck by the disease is in Asia. With 87% of confirmed cases and 91% of deaths, Asia is also one of the continent most heavily affected. Like the neighbouring countries in South-East Asia, Cambodia has been repeatedly hit by avian flu in the recent years. The measures implemented to prevent the spread of A/H5N1 virus in farms, to improve the behaviour of farmers and to clean up the poultry markets emphasize the multiple difficulties to control this zoonosis. Meanwhile, influenza surveillance is being carried out in humans, based on a reporting system and a network of sentinel hospitals connected to the Institut Pasteur du Cambodge. Thus, Cambodia takes an active part in the wide international network which should quickly detect any mutational event among avian flu viruses that might lead to the emergence of a pandemic.

Multicenter study of street foods in 13 towns on four continents by the food and environmental hygiene study group of the international network of pasteur and associated institutes.

An international multicenter study of ready-to-eat foods, sandwiches, and ice creams or sorbets sold in the streets and their vendors was carried out to assess the microbiological quality of these foods and to identify characteristics of the vendors possibly associated with pathogens. Thirteen towns in Africa, America, Asia, and Oceania were involved in the study. A single protocol was used in all 13 centers: representative sampling was by random selection of vendors and a sample of foods bought from each of these vendors at a time and date selected at random. Microbiological analyses were carried out using standardized Association Française de Normalisation methods, and the use of a standardized questionnaire to collect data concerning the characteristics of the vendors. Fifteen surveys were carried out, with 3,003 food samples from 1,268 vendors. The proportion of unsatisfactory food samples was between 12.7 and 82.9% for ice creams and sorbets and between 11.3 and 92% for sandwiches. For ice creams and sorbets, the sale of a large number of units (>80 per day) increased the risk of unsatisfactory food by a factor of 2.8 (95% confidence interval [CI]: 1.5 to 5.1), lack of training in food hygiene by 6.6 (95% CI: 1.1 to 50). and by a factor of 2.8 (95% CI: 1.4 to 5.4) for mobile vendors. These risk factors were not identified for sandwiches, this difference may be due to the presence of a cooking step in their preparation. These results show that the poor microbiological quality of these street foods constitutes a potential hazard to public health, that the extent of this hazard varies between the cities studied, and that vendors' health education in food safety is a crucial factor in the prevention of foodborne infections.

[Microbiological quality of " ice, ice cream. sorbet" sold on the streets of Phnom Penh; April 1996-April 1997]. / Qualité microbiologique de l'aliment "glace, crème glacée, sorbet" vendu dans les rues de la ville de Phnom Penh; avril 1996-avril 1997.

A study of the microbiological quality of ice lice creams/sorbets sold on the streets of Phnom Penh city was conducted from April 1996 to April 1997. Socio-demographic and environmental characteristics with two ice/ice creams samples were collected from vendors selected in the city. A total of 105 vendors and 210 ice/ice creams samples were randomly selected for the study period. Ice/ice cream vendors in the streets of Phnom Penh were adults (mean age: 28 years old) with a male predominance (86.5%). Mean educational level of vendors was 5 years with no training in mass catering. Most ice creams and sorbets (81.7%) were made using traditional methods. Microbiological analysis performed in the laboratory of Pasteur Institute of Cambodia indicated the poor bacteriological quality of the samples. The proportions of samples classified unsafe according to microbiological criteria were 83.3% for total bacterial count at 30 degrees C, 70% for total coliforms, 30% for faecal coliforms, 12.2% for Staphylococcus aureus and 1.9% for presence of Salmonella spp. These bacterial results suggest that many other food products sold in the streets may be similarly poor. Safety measures should be undertaken to avoid potential threats. Regulation of the street food sector should be part of a larger strategy for enhanced food safety and environmental quality in the city.

[Incidence of HIV infection in consultants reviewed after a first negative test in an anonymous and free screening center at the Institut Pasteur of Cambodia, 1996-1999]. / Incidence de l'infection VIH parmi les consultants revus après un premier test négatif au centre de dépistage anonyme et gratuit de l'Institut Pasteur du Cambodge, 1996-1999.

A retrospective study was performed to determine the incidence of HIV seroconversion among repeat consultants attending the voluntary testing and counselling centre of the Institut Pasteur of Cambodia as well as factors associated with HIV seroconversion. From 1996 to 1999, 5541 repeat consultants were selected for the study. Exclusion criteria included being aged under 15 years, having initially tested positive or inconclusive and a time span of fewer than 30 days since the last test. In all, 276 persons had seroconverted to HIV, giving an incidence rate of 5.56 per 100 person-years. The seroconversion rate declined from 8.46% in 1996, to 3.06% in 1999 (chi 2 test for trend, p = 10(-5)). Among the risk factors analysed, 3 were significantly associated with lack of seroconversion: being a student (RR = 0.53, p = 0.032) or a civil servant (RR = 0.63, p = 0.012) and systematic condom use with causal partners (RR = 0.37, p = 10(-5)). The decline of HIV seroconversion among repeat consultants attending the VCT centre over the study period may reflect changes in risk behaviour and the beneficial impact of counselling.

[Evaluation of the epidemic caused by the human immunodeficiency virus in Cambodia]. / Bilan de l'épidémie due au virus de l'immunodéficience humaine au Cambodge.

The infection by the human immunodeficiency virus is in the process of expanding to a dramatical level in South East Asia. At the moment, the few available datas on Cambodia are increasingly worrying, with a rate of seropositivity of prostitutes higher than 9% in 1992 and a clear progression of the rate of seropositivity of blood donors: 1.3% by the second quarter of 1993.