Quantitative data on Campylobacter contamination of food are lacking, notably in developing countries. We assessed Campylobacter contamination of chicken neck-skins at points of slaughter in 5 major ...cities in Africa (Dakar in Senegal, Yaounde in Cameroon), Oceania (Noumea in New Caledonia), the Indian Ocean (Antananarivo in Madagascar) and Asia (Ho Chi Minh City (HCMC) in Vietnam.
One hundred and fifty slaughtered chickens were collected in each of the 5 major cities from semi-industrial abattoirs or markets (direct slaughter by the seller), and 65.5% (491/750) were found to be Campylobacter-positive. Two cities, Yaounde and Noumea, demonstrated high prevalence Campylobacter detection rates (92.7% and 96.7% respectively) in contrast with HCMC (15.3%).
Four species were identified among 633 isolates, namely C. jejuni (48.3%), C. coli (37.3%), C. lari (11.7%) and C. upsaliensis (1%). HCMC was the only city with C. lari isolation as was Antananarivo for C. upsaliensis. C. coli was highly prevalent only in Yaounde (69.5%).
Among the 491 samples positive in Campylobacter detection, 329 were also positive with the enumeration method. The number of Campylobacter colony-forming units (CFU) per gram of neck-skin in samples positive in enumeration was high (mean of the log10: 3.2 log10 CFU/g, arithmetic mean: 7900CFU/g). All the cities showed close enumeration means except HCMC with a 1.81 log10 CFU/g mean for positive samples. Semi-industrial abattoir was linked to a significant lower count of Campylobacter contamination than direct slaughter by the seller (p=0.006).
On 546 isolates (546/633, 86.3%) tested for antibiotic susceptibility, resistance to erythromycin, ampicillin and ciprofloxacin was observed for respectively 11%, 19% and 50%. HCMC was the city where antibiotic resistant rates were the highest (95%, p=0.014).
Considering the 329 positive chickens in Campylobacter enumeration, the mean number of resistant isolates to at least 2 different antibiotic families (19.8%), may be estimated ca. 1500CFU/g; the corresponding mean of the log10 would be 2.5 log10CFU/g.
As chickens are sold at slaughter and brought directly at home to be cooked, these data suggest a high probability of cross-contamination. A substantial proportion of isolates are drug-resistant, which could lead to potential public health issues. Health authorities should consider measures to reduce Campylobacter contamination of chicken during farming and at slaughter, and to provide appropriate food hygiene education. Further studies are needed in particular to investigate food-handling practices in domestic kitchens.
► This multicentre study was conducted in 5 major cities on 4 different continents. ► 65.5% chicken neck-skins were found to be Campylobacter-positive. ► The mean number of Campylobacter was 7900CFU/g for samples positive in enumeration. ► The mean of the log10 was 3.2 log10 CFU/g. ► 19.8% of isolates were resistant to at least 2 different antibiotic families.
In the context of the revision of the Codex Alimentarius Commission document “Principles for the Establishment and Application of Microbiological Criteria CAC/GL 21/1997”, and in the scope of an ...FAO/WHO pilot project, seven examples on the application of microbiological criteria were developed to help illustrate the different contexts in which microbiological criteria might be used. This example describes a Good Hygiene Practice (GHP)-based microbiological criterion (MC), following the structure agreed by FAO/WHO. A GHP-based MC is a criterion used to monitor the production process of an establishment, to verify if it is functioning as expected and that GHPs are correctly implemented. For the development of this example, the authors chose raw meat preparations as the food commodity of interest, and Escherichia coli as an indicator of the effectiveness of GHPs during production. The sampling plan, including the values of M, m, n, and c, the analytical unit size, the analytical method, interpretation of results and corrective actions in case of non-conformance were based on empirical knowledge and on legislative rules in the countries of origin of the authors. This example is to illustrate the general approach which can be taken to establish such criteria and can be applied to other foods and for other microbiological contaminants.
•Development of a GHP-based microbiological criterion following a structured approach.•GHP-based microbiological criterion to assess correct implementation of GHP.•Sampling plan adapted to the specific commodity/food.•Corrective measures to be taken when unsatisfactory results are detected.
From February 2006 to January 2007, 150 chickens were collected from eight retail markets in Yaounde, and 90 (60%) tested positive for Salmonella. Seventy-nine chickens were contaminated with only ...one Salmonella serotype, 10 with two different serotypes, and 1 with four serotypes. The most prevalent serotypes were Enteritidis (47 strains) and Hadar (29 strains). The isolates were tested for their susceptibilities to amoxicillin, amoxicillin/clavulanic acid, cefoxitin, cefotaxime, gentamicin, streptomycin, tetracycline, chloramphenicol, sulfonamides, nalidixic acid, ciprofloxacin, and trimethoprim/sulfamethazole by disk diffusion assay. Minimum inhibitory concentrations of ampicillin, streptomycin, tetracycline, sulfonamides, and nalidixic acid were determined for the resistant strains by agar dilution method. Eleven isolates (10.7%) of the 103 tested were susceptible to all antimicrobials. Resistance was most observed to tetracycline (84.5%), streptomycin (44.7%), and nalidixic acid (34%). Forty-one isolates (39.8%) were multidrug resistant (resistant to three or more antimicrobials from different classes), of which 68.3% were Hadar and 21.9% Enteritidis. The most frequent resistant pattern in Hadar was streptomycin-tetracycline-nalidixic acid. These results highlight once more the need for surveillance of Salmonella contamination in poultry.
There was an outbreak of cholera in Cameroon during 2004 and 2005; the epidemic began in Douala in January 2004 and spread throughout the south of the country. The World Health Organization (WHO) ...reported 8005 cases in 2004 and 2847 cases in 2005. Five hundred eighty-nine stool samples were received in the Pasteur Centre of Cameroon and 352 were microbiologically confirmed to be positive for Vibrio cholerae O1. Isolated strains were tested for their antimicrobial susceptibilities. All the strains were multidrug resistant and predominantly showed a common resistance pattern at the beginning of the outbreak. Tetracycline, recommended by the WHO for treating cholera in adults, was effective against all the strains tested. Cotrimoxazole (trimethoprim/sulfamethoxazole), previously a first-line treatment in children, was ineffective in vitro for all the clinical isolates and was quickly replaced by amoxicillin. Ampicillin resistance emerged at the end of 2004 and was the leading resistance pattern observed in the second half of 2005. This therefore represented the second major resistance pattern. These two major resistance profiles were not associated with patient characteristics (sex and age) or to the geographic origin of strains. However, there was a highly significant relationship between resistance patterns and the year of isolation (p<0.001). The strains possessed genes ctxA and ctxB encoding the two cholera toxin subunits and were very closely related, irrespective of their antimicrobial resistance patterns. They were not differentiated by molecular typing methods and gave similar ribotyping and pulsed-field gel electrophoresis patterns.
We investigated an acute foodborne outbreak in Yaounde, Cameroon, following a private party. Plesiomonas shigelloides, which has rarely been reported as the causative agent of foodborne outbreaks, ...was strongly suspected. The unusual short incubation period suggested the presence of a preformed toxin within the incriminated food.
Organisms of the genera Cryptosporidium and Giardia are enteric parasites that are responsible for cryptosporidiosis and giardiasis respectively. They are characterised by profuse diarrhoea, ...abdominal pain and cramping. The symptoms can be fatal for immunodepressed subjects and children because these are opportunistic pathogens. These pathogenic infections are rampant in developing countries due to the unhygienic and improper disposal of wastewater and the use of surface water as the major sources of potable water. Little information is available about the resistant forms of these microorganisms in the hydrosystems of Cameroon in particular and other sub-Saharan ecosystems in general. The aim of this research was to isolate, identify, and measure these forms of these emerging protozoa in the waste and surface waters of Yaoundé, Cameroon. Giardia spp cysts were identified by Lugol iodine staining, and the Cryptosporidium spp oocysts by the Ziehl-Neelsen technique. The cysts were oval in structure and varied in length from 7 um to 12.0 um. Axostyles were visible along the median line and nuclei were present. The oocysts were round in structure and varied in diameter from 4 um to 6 um. A double cell wall was seen in the apicomplexa. The highest concentrations of Giardia spp cysts were 560 cysts/L in the surface water and 650 cysts/L in the residual effluent, while the corresponding figures for Cryptosporidium spp were 1,110 oocysts/L in the stream and 1,500 oocysts/L in the effluent. The cyst and oocyst counts were higher in the direct effluent because they are released directly into the wastewater by feces, while they are diluted in the surface water, reducing their abundance. Turbidity has a significant effect (p<0.05) on the population dynamics of these microorganisms, thereby indicating the importance of suspended or colloidal particles in the dissemination of these pathogens in aquatic media. The suspended particles in the wastewater adsorb the oocysts and cysts, probably because of the interactions between the electric charges carried by suspended particles and those present at the surface of the parasites. The positive correlation observed between these parasites and ammonia may account for some of the die-off of these resistant forms, because ammonium ions in water are known to inactivate trophozoites and sporozoites present in cysts and oocysts. This may be due to the permeability of the protozoan membrane to the ammonium ion and other alkaline earth metals present in aqueous form in the biotope. These parasite forms in these media represent a considerable health risk to the inhabitants of the study zone who depend on this surface water for drinking. The small size of these parasitic forms, the nonfunctional water purification stations and ineffective water treatment systems expose the community to outbreaks of giardiasis and cryptosporidiosis.
