Characterization of virulence factors of Salmonella isolated from human stools and street food in urban areas of Burkina Faso.

BACKGROUND: This study was undertaken to identify and functionally characterize virulence genes from Salmonella isolates in street food and stool cultures. From February 2017 to May 2018, clinical and food Salmonella strains were isolated in three regions in Burkina Faso. Salmonella was serotyped according to the White-Kauffmann-Le Minor method, and polymerase chain reaction (PCR) was used to detec invA, spvR, spvC, fimA and stn virulence genes commonly associated with salmonellosis in Sub-Saharan Africa. RESULTS: A total of 106 Salmonella isolates (77 human stools; 14 sandwiches) was analyzed using a serological identification with an O-group test reagent. The presence of Salmonella was confirmed in 86% (91/106) of the samples were reactive (OMA-positive/OMB-positive). Salmonella serogroup O:4,5 was the most common serogroup detected (40%; 36/91). Salmonella Enteritidis and Typhimurium represented 5.5% (5/91) and 3.3% (3/91), respectively and were identified only from clinical isolates. Furthermore, 14 serotypes of Salmonella (12/91 human strains and 2/15 sandwich strains) were evocative of Kentucky/Bargny serotype. For the genetic profile, 66% (70/106) of the Salmonella had invA and stn genes; 77.4% (82/106) had the fimA gene. The spvR gene was found in 36.8% (39/106) of the isolates while 48.1% (51/106) had the spvC gene. Among the identified Salmonella Enteritidis and Salmonella Typhimurium isolated from stools, the virulence genes detected were invA (3/5) versus (2/3), fimA (4/5) versus (3/3), stn (3/5) versus (2/3), spvR (4/5) versus (2/3) and spvC (3/5) versus (2/3), respectively. CONCLUSION: This study reports the prevalence of Salmonella serotypes and virulence genes in clinical isolates and in street foods. It shows that food could be a significant source of Salmonella transmission to humans. Our results could help decision-making by the Burkina Faso health authority in the fight against street food-related diseases, in particular by training restaurateurs in food hygiene.

Household cockroaches carry CTX-M-15-, OXA-48- and NDM-1-producing enterobacteria, and share beta-lactam resistance determinants with humans.

BACKGROUND: This study was designed to investigate whether household cockroaches harbor cephalosporin-resistant enterobacteria that share resistance determinants with human inhabitants. From February through July 2016, whole cockroach homogenates and human fecal samples from 100 households were cultured for cephalosporin-resistant enterobacteria (CRe). The CRe were examined for plasmid-mediated AmpC, ESBL, and carbapenemase genes; antibiotic susceptibility patterns; and conjugative transfer of antibiotic resistance mechanisms. Clonal associations between CRe were determined by multi-locus sequence typing (MLST). RESULTS: Twenty CRe were recovered from whole cockroach homogenates from 15 households. The prevalence of households with cockroaches that harbored CRe, AmpC- (based on phenotype, with no identifiable blaAmpC genes), ESBL-, and carbapenemase-producers were 15, 4, 5%(2 blaCTX-M-15/TEM-1; 1 blaCTX-M-15/TEM-4; 1 blaTEM-24; 1 blaSHV-4) and 3%(2 blaNDM-1 genes and 1 blaOXA-48 gene), respectively. Overall, 20 CRe were recovered from 61 fecal samples of inhabitants from all 15 households that had cockroach samples positive for CRe. Of these, 5CRe (1 per household) were positive for ESBLs (blaTEM-24, blaTEM-14, blaCTX-M-15/TEM-4, blaSHV-3, blaCTX-M-15/TEM-1) and none carried AmpCs or carbapenemases. From 4% of households, the pair of cockroach and human CRe shared the same sequence type (ST), clonal complex (CC), antibiogram, and conjugable bla gene sequence (house 34, E. coli ST9/CC20-blaTEM-4; house 37, E. coli ST44/CC10-blaCTX-15/TEM-4; house 41, E. coli ST443/CC205-blaCTX-15/TEM-1; house 49, K. pneumoniae ST231/CC131-blaSHV-13). CONCLUSION: The findings provide evidence that household cockroaches may carry CTX-M-15-, OXA-48- and NDM-1-producers, and share clonal relationship and beta-lactam resistance determinants with humans.

Salmonella spp. and Campylobacter spp. in poultry feces and carcasses in Ouagadougou, Burkina Faso.

The importance of Salmonella and Campylobacter as foodborne pathogens is well recognized worldwide. Poultry and poultry products are commonly considered as the major vehicles of Salmonella and Campylobacter infection in humans. The aim of this study was to investigate the hygienic status of poultry facilities and determine the prevalence of Salmonella and Campylobacter in slaughtered poultry feces and carcasses in four different markets in Ouagadougou, capital city of Burkina Faso. A total of 103 poultry feces and 20 carcasses were analyzed using microbiological standard methods. Among the 103 fecal samples, 70 were positive for Campylobacter ssp (67.96%) and 54 for Salmonella ssp (52.42%). The hippurate hydrolysis test revealed that among the 70 Campylobacter strains isolated from feces, 49 were C. jejuni (70%) and 21 were C. coli (30%). From the 20 carcasses analyzed, 18 were contaminated with Salmonella (90%) and 10 with Campylobacter ssp (50%). Among the 10 Campylobacter ssp samples isolated from poultry carcasses, all were identified as C. jejuni using the API CAMPY system and the hippurate hydrolysis test. The assessment of markets hygienic practices for production, transportation, display, and vending of meat revealed unhygienic conditions. To complete the observation of unhygienic practices, we have sampled chicken-washing solution from the study sites and microbiological analysis of these samples revealed the presence of Salmonella spp in 100% of the samples. This study highlighted that poultry products on sale in Ouagadougou are highly contaminated with Salmonella and Campylobacter. To the best of our knowledge, this is the first report describing Campylobacter presence in the poultry industry of Burkina Faso. Our findings might help to better understand the epidemiology of Salmonella and Campylobacter.

Characterization of Diarrheagenic Escherichia coli Isolated in Organic Waste Products (Cattle Fecal Matter, Manure and, Slurry) from Cattle's Markets in Ouagadougou, Burkina Faso.

Cattle farming can promote diarrheal disease transmission through waste, effluents or cattle fecal matter. The study aims to characterize the diarrheagenic Escherichia coli (DEC) isolated from cattle feces, manure in the composting process and slurry, collected from four cattle markets in Ouagadougou. A total of 585 samples (340 cattle feces, 200 slurries and 45 manures in the composting process) were collected from the four cattle markets between May 2015 and May 2016. A multiplex Polymerase Chain Reaction (PCR), namely 16-plex PCR, was used to screen simultaneously the virulence genes specific for shiga toxin-producing E. coli (STEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC) and enteroaggregative E. coli (EAEC). DEC was detected in 10.76% of samples. ETEC was the most prevalent (9.91%). STEC and EAEC have been observed with the same rate (0.51%). ETEC were detected in 12.64% of cattle feces, in 6.66% of manure in the composting process and in 5% of slurry. STEC were detected in 0.58% of cattle feces and in 2.22% of manure in the composting process. EAEC was detected only in 1% of slurry and in 2.22% of manure in the composting process. ETEC strains were identified based on estIa gene and/or estIb gene and/or elt gene amplification. Of the 58 ETEC, 10.34% contained astA, 17.24% contained elt, 3.44% contained estIa and 79.31% contained estIb. The two positive EAEC strains contained only the aggR gene, and the third was positive only for the pic gene. The results show that effluent from cattle markets could contribute to the spreading of DEC in the environment in Burkina Faso.