RESUMEN
Invasive non-typhoidal Salmonella (iNTS) (serotypes Typhimurium and Enteritidis) are major causes of bloodstream infections in sub-Saharan Africa, but their reservoir is unknown. Aiming to demonstrate human carriers as a reservoir, we assessed an iNTS disease endemic rural community (Kikonka health area, Democratic Republic of the Congo) for intestinal carriage of iNTS. After a census, healthy subjects from randomly selected households provided three successive stool samples for Salmonella culture. We next compared the stool isolates for genetic relatedness with time and health area-matched blood culture isolates obtained from hospitalized patients by multiple locus variable-number tandem repeat analysis (MLVA) and performed whole genome sequencing (WGS) on a subset of stool and blood isolates. Among 2,354 eligible subjects, 2,234 (94.9%) consented and provided at least one stool sample, and 2,219 (94.3%) provided three stool samples. The cumulative proportion of Salmonella carriers after 3 days was 4.4% (n = 98). S. Typhimurium and Enteritidis were found in 26 and 3 carriers, respectively, representing 1.3% (29 out of 2,234) of participants living in 6.0% (26 out of 482) of households. MLVA types of all 26 S. Typhimurium stool isolates matched with the corresponding MLVA types of blood isolates. The MLVA type of one out of three Enteritidis stool isolates matched the single MLVA type of the five Enteritidis blood isolates. WGS analysis of S. Typhimurium (n = 20) and S. Enteritidis (n = 4) isolates revealed Typhimurium multilocus sequence type (ST)313 Lineage 2 and Enteritidis ST11 Central/Eastern African and Outlier clades and confirmed the MLVA clustering. More than three-quarters of Typhimurium isolates showed combined multidrug resistance, ceftriaxone resistance, and fluoroquinolone non-susceptibility. In conclusion, the present study demonstrated iNTS carriage among healthy community members, with stool isolates that were genetically similar to blood culture isolates obtained in patients from the same community. These findings contribute to the evidence of a human reservoir of iNTS.
RESUMEN
Background: Typhoid intestinal perforation (TIP) remains the most serious complication of typhoid fever. In many countries, the diagnosis of TIP relies on intraoperative identification, as blood culture and pathology capacity remain limited. As a result, many cases of TIP may not be reported as typhoid. This study demonstrates the burden of TIP in sites in Burkina Faso, Democratic Republic of Congo (DRC), Ethiopia, Ghana, Madagascar, and Nigeria. Methods: Patients with clinical suspicion of nontraumatic intestinal perforation were enrolled and demographic details, clinical findings, surgical records, blood cultures, tissue biopsies, and peritoneal fluid were collected. Participants were then classified as having confirmed TIP, probable TIP, possible TIP, or clinical intestinal perforation based on surgical descriptions and cultures. Results: A total of 608 participants were investigated for nontraumatic intestinal perforation; 214 (35%) participants had surgically-confirmed TIP and 33 participants (5%) had culture-confirmed typhoid. The overall proportion of blood or surgical site Salmonella enterica subspecies enterica serovar Typhi positivity in surgically verified TIP cases was 10.3%. TIP was high in children aged 5-14 years in DRC, Ghana, and Nigeria. We provide evidence for correlation between monthly case counts of S. Typhi and the occurrence of intestinal perforation. Conclusions: Low S. Typhi culture positivity rates, as well as a lack of blood and tissue culture capability in many regions where typhoid remains endemic, significantly underestimate the true burden of typhoid fever. The occurrence of TIP may indicate underlying typhoid burden, particularly in countries with limited culture capability.
RESUMEN
BACKGROUND: Clinical observations and animal studies have suggested that Salmonella intestinal carriage is promoted by concurrent Schistosoma infection. The present study assessed association of Salmonella intestinal carriage and Schistosoma mansoni infection among individuals in a Schistosoma endemic area in sub-Saharan Africa. METHODS: From November 2015 to March 2016, a cross-sectional community-wide study was conducted in Kifua II, a rural village in Kongo Central Province, Democratic Republic of Congo. Stool samples were collected and analyzed for Salmonella intestinal carriage (culture) and Schistosoma mansoni infection (Kato Katz microscopy with determination of egg load). Salmonella Typhimurium and Enteritidis isolates were assessed for genetic similarity with blood culture isolates obtained during the same period in a neighboring hospital using multi-locus variable-numbers tandem repeat analysis (MLVA). RESULTS: A total of 1,108 participants were included (median age 15 years (IQR: 7-36), male-to-female ratio of 1:1.1). The overall prevalence of Schistosoma mansoni infection and non-typhoidal Salmonella carriage was 51.2% (95% CI: 48.2-54.1) and 3.4% (95% CI: 2.5-4.7) respectively, with 2.2% (95% CI: 1.5-3.2) of participants coinfected. The proportion of Salmonella carriage tended to be higher among Schistosoma mansoni infected participants compared to non-infected participants but this difference did not reach statistical significance (4.2% versus 2.6%, p = 0.132). However, the proportion of Salmonella carriage among participants with a heavy Schistosoma mansoni infection was significantly higher compared to those with a light and moderate infection (8.7% versus 3.2%, p = 0.012) and compared to Schistosoma mansoni negatives (8.7% versus 2.6%, p = 0.002). The 38 Salmonella isolates comprised five and four Enteritidis and Typhimurium serotypes respectively, the majority of them had MLVA types identical or similar to those observed among blood culture isolates. CONCLUSION: Salmonella intestinal carriage was associated with a heavy intensity of Schistosoma mansoni infection. Further studies are needed to address causation.