Longitudinal Assessment of Antibiotic Resistance in Fecal Escherichia coli in Tanzanian Children

Epidemiology and multiple colonization of gastrointestinal pathogens in rural Tanzanian children with and without diarrhea: A case-control study

Diarrheal diseases are important causes of morbidity and mortality, worldwide. The occurrence of multiple pathogens in stool samples of symptomatic and asymptomatic individuals in resource-limited countries have been repeatedly described. In this study, we assessed the differentiated effects of combined pathogen detections on recorded symptoms. A case-control study was conducted among 620 under-five-year-old children in rural northeastern Tanzania with emphasis of multiple detection. The median age of children was 11 months (IQR = 7, 20), and 52.1% were male. Cases (50.2%, n = 157) were less likely than controls (64.5%, n = 198) to have multiple colonization with gastrointestinal tract (GIT) pathogens. The children's age was positively associated with the likelihood of harboring multiple GIT pathogens [OR, 1.02, 95% CI = 1.01, 1.04]. Shigella spp./enteroinvasive Escherichia coli (EIEC) [OR = 2.80, 95% CI 1.62, 4.83] and norovirus [OR = 2.04, 95% CI 1.23, 3.39] were more common in cases and were strongly associated with diarrhea, while enteroaggregative E. coli (EAEC) [OR = 0.23, 95%CI 0.17-0.33] were more common in controls. Diarrheal diseases in under-five children from rural Tanzania are likely to be due to infections with Shigella spp./EIEC, and norovirus with strongly age-dependent associations.

Short reads-based characterization of pathotype diversity and drug resistance among Escherichia coli isolated from patients attending regional referral hospitals in Tanzania

BACKGROUND

Escherichia coli is known to cause about 2 million deaths annually of which diarrhea infection is leading and typically occurs in children under 5 years old. Although Africa is the most affected region there is little information on their pathotypes diversity and their antimicrobial resistance.

OBJECTIVE

To determine the pathotype diversity and antimicrobial resistance among E. coli from patients attending regional referral hospitals in Tanzania.

MATERIALS AND METHODS

A retrospective cross-section laboratory-based study where a total of 138 archived E. coli isolates collected from 2020 to 2021 from selected regional referral hospitals in Tanzania were sequenced using the Illumina Nextseq550 sequencer platform. Analysis of the sequences was done in the CGE tool for the identification of resistance genes and virulence genes. SPSS version 20 was used to summarize data using frequency and proportion.

RESULTS

Among all 138 sequenced E. coli isolates, the most prevalent observed pathotype virulence genes were of extraintestinal E. coli UPEC fyuA gene 82.6% (114/138) and NMEC irp gene 81.9% (113/138). Most of the E. coli pathotypes observed exist as a hybrid due to gene overlapping, the most prevalent pathotypes observed were NMEC/UPEC hybrid 29.7% (41/138), NMEC/UPEC/EAEC hybrid 26.1% (36/138), NMEC/UPEC/DAEC hybrid 18.1% (25/138) and EAEC 15.2% (21/138). Overall most E. coli carried resistance gene to ampicillin 90.6% (125/138), trimethoprim 85.5% (118/138), tetracycline 79.9% (110/138), ciprofloxacin 76.1% (105/138) and 72.5% (100/138) Nalidixic acid. Hybrid pathotypes were more resistant than non-hybrid pathotypes.

CONCLUSION

Whole genome sequencing reveals the presence of hybrid pathotypes with increased drug resistance among E. coli isolated from regional referral hospitals in Tanzania.

Review and analysis of the overlapping threats of carbapenem and polymyxin resistant E. coli and Klebsiella in Africa

BACKGROUND

Carbapenem-resistant Enterobacterales are among the most serious antimicrobial resistance (AMR) threats. Emerging resistance to polymyxins raises the specter of untreatable infections. These resistant organisms have spread globally but, as indicated in WHO reports, the surveillance needed to identify and track them is insufficient, particularly in less resourced countries. This study employs comprehensive search strategies with data extraction, meta-analysis and mapping to help address gaps in the understanding of the risks of carbapenem and polymyxin resistance in the nations of Africa.

METHODS

Three comprehensive Boolean searches were constructed and utilized to query scientific and medical databases as well as grey literature sources through the end of 2019. Search results were screened to exclude irrelevant results and remaining studies were examined for relevant information regarding carbapenem and/or polymyxin(s) susceptibility and/or resistance amongst E. coli and Klebsiella isolates from humans. Such data and study characteristics were extracted and coded, and the resulting data was analyzed and geographically mapped.

RESULTS

Our analysis yielded 1341 reports documenting carbapenem resistance in 40 of 54 nations. Resistance among E. coli was estimated as high (> 5%) in 3, moderate (1-5%) in 8 and low (< 1%) in 14 nations with at least 100 representative isolates from 2010 to 2019, while present in 9 others with insufficient isolates to support estimates. Carbapenem resistance was generally higher among Klebsiella: high in 10 nations, moderate in 6, low in 6, and present in 11 with insufficient isolates for estimates. While much less information was available concerning polymyxins, we found 341 reports from 33 of 54 nations, documenting resistance in 23. Resistance among E. coli was high in 2 nations, moderate in 1 and low in 6, while present in 10 with insufficient isolates for estimates. Among Klebsiella, resistance was low in 8 nations and present in 8 with insufficient isolates for estimates. The most widespread associated genotypes were, for carbapenems, blaOXA-48, blaNDM-1 and blaOXA-181 and, for polymyxins, mcr-1, mgrB, and phoPQ/pmrAB. Overlapping carbapenem and polymyxin resistance was documented in 23 nations.

CONCLUSIONS

While numerous data gaps remain, these data show that significant carbapenem resistance is widespread in Africa and polymyxin resistance is also widely distributed, indicating the need to support robust AMR surveillance, antimicrobial stewardship and infection control in a manner that also addresses broader animal and environmental health dimensions.

Implementation of antibiotic stewardship programmes in paediatric patients in regional referral hospitals in Tanzania: experience from prescribers and dispensers

BACKGROUND

In 2017, Tanzania launched the National Action Plan for Antimicrobial Resistance (NAPAR), 2017-2022 and implementation of antibiotic stewardship programmes (ASPs) was one of the agendas. Since the launch of the National Action Plan, no study has been done to assess its implementation.

OBJECTIVES

To explore the experiences of prescribers and dispensers on implementing ASPs among paediatric patients attending Regional Referral Hospitals (RRHs) in Tanzania.

METHODS

An exploratory qualitative study was conducted among key informants, in 14 RRHs in Tanzania between July and August 2020. A total of 28 key informants, 14 dispensers in charge of pharmacies and 14 medical doctors in charge of paediatric departments (prescribers), were interviewed. A hybrid thematic analysis was conducted on the gathered information.

RESULTS

Most of the study participants were not conversant with the term 'antibiotic stewardship'. Some had heard about the programmes but were not aware of the activities involved in the programme. Those who were knowledgeable on ASPs mentioned the lack of existence of such programmes in their settings. They further added that absence or limited knowledge of the stewardship concepts may have influenced the current poor practices. Barriers to the implementation of ASPs mentioned were lack of laboratory facilities to support culture and susceptibility tests, lack of materials and reagents, management pressure to prevent loss or to generate income, patients' influence and limited training opportunities.

CONCLUSIONS

Despite launching the NAPAR in 2017, we found limited implementation of ASPs in the management of paediatric patients. This study highlighted some barriers and identified possible intervention points.

Effect of scheduled antimicrobial and nicotinamide treatment on linear growth in children in rural Tanzania: A factorial randomized, double-blind, placebo-controlled trial

BACKGROUND

Stunting among children in low-resource settings is associated with enteric pathogen carriage and micronutrient deficiencies. Our goal was to test whether administration of scheduled antimicrobials and daily nicotinamide improved linear growth in a region with a high prevalence of stunting and enteric pathogen carriage.

METHODS AND FINDINGS

We performed a randomized, 2 × 2 factorial, double-blind, placebo-controlled trial in the area around Haydom, Tanzania. Mother-child dyads were enrolled by age 14 days and followed with monthly home visits and every 3-month anthropometry assessments through 18 months. Those randomized to the antimicrobial arm received 2 medications (versus corresponding placebos): azithromycin (single dose of 20 mg/kg) at months 6, 9, 12, and 15 and nitazoxanide (3-day course of 100 mg twice daily) at months 12 and 15. Those randomized to nicotinamide arm received daily nicotinamide to the mother (250 mg pills months 0 to 6) and to the child (100 mg sachets months 6 to 18). Primary outcome was length-for-age z-score (LAZ) at 18 months in the modified intention-to-treat group. Between September 5, 2017 and August 31, 2018, 1,188 children were randomized, of whom 1,084 (n = 277 placebo/placebo, 273 antimicrobial/placebo, 274 placebo/nicotinamide, and 260 antimicrobial/nicotinamide) were included in the modified intention-to-treat analysis. The study was suspended for a 3-month period by the Tanzanian National Institute for Medical Research (NIMR) because of concerns related to the timing of laboratory testing and the total number of serious adverse events (SAEs); this resulted in some participants receiving their final study assessment late. There was a high prevalence of stunting overall (533/1,084, 49.2%). Mean 18-month LAZ did not differ between groups for either intervention (mean LAZ with 95% confidence interval [CI]: antimicrobial: -2.05 CI -2.13, -1.96, placebo: -2.05 CI -2.14, -1.97; mean difference: 0.01 CI -0.13, 0.11, p = 0.91; nicotinamide: -2.06 CI -2.13, -1.95, placebo: -2.04 CI -2.14, -1.98, mean difference 0.03 CI -0.15, 0.09, p = 0.66). There was no difference in LAZ for either intervention after adjusting for possible confounders (baseline LAZ, age in days at 18-month measurement, ward, hospital birth, birth month, years of maternal education, socioeconomic status (SES) quartile category, sex, whether the mother was a member of the Datoga tribe, and mother's height). Adverse events (AEs) and SAEs were overall similar between treatment groups for both the nicotinamide and antimicrobial interventions. Key limitations include the absence of laboratory measures of pathogen carriage and nicotinamide metabolism to provide context for the negative findings.

CONCLUSIONS

In this study, we observed that neither scheduled administration of azithromycin and nitazoxanide nor daily provision of nicotinamide was associated with improved growth in this resource-poor setting with a high force of enteric infections. Further research remains critical to identify interventions toward improved early childhood growth in challenging conditions.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03268902.