Antimicrobial Resistance in Enterobacterales and Its Contribution to Sepsis in Sub-saharan Africa

Carriage of third-generation cephalosporin-resistant and carbapenem-resistant Enterobacterales among children in sub-Saharan Africa: a systematic review and meta-analysis

Background

The increasing resistance of Enterobacterales to third-generation cephalosporins and carbapenems in sub-Saharan Africa (SSA) is a major public health concern. We did a systematic review and meta-analysis of studies to estimate the carriage prevalence of Enterobacterales not susceptible to third-generation cephalosporins or carbapenems among paediatric populations in SSA.

Methods

We performed a systematic literature review and meta-analysis of cross-sectional and cohort studies to estimate the prevalence of childhood (0-18 years old) carriage of extended-spectrum cephalosporin-resistant Enterobacterales (ESCR-E) or carbapenem-resistant Enterobacterales (CRE) in SSA. Medline, EMBASE and the Cochrane Library were searched for studies published from 1 January 2005 to 1 June 2022. Studies with <10 occurrences per bacteria, case reports, and meta-analyses were excluded. Quality and risk of bias were assessed using the Newcastle-Ottawa scale. Meta-analyses of prevalences and odds ratios were calculated using generalised linear mixed-effects models. Heterogeneity was assessed using I2 statistics. The protocol is available on PROSPERO (CRD42021260157).

Findings

Of 1111 studies examined, 40 met our inclusion criteria, reporting on the carriage prevalence of Enterobacterales in 9408 children. The pooled carriage prevalence of ESCR-E was 32.2% (95% CI: 25.2%-40.2%). Between-study heterogeneity was high (I2 = 96%). The main sources of bias pertained to participant selection and the heterogeneity of the microbiological specimens. Carriage proportions were higher among sick children than healthy ones (35.7% vs 16.9%). The pooled proportion of nosocomial acquisition was 53.8% (95% CI: 32.1%-74.1%) among the 922 children without ESCR-E carriage at hospital admission. The pooled odds ratio of ESCR-E carriage after antibiotic treatment within the previous 3 months was 3.20 (95% CI: 2.10-4.88). The proportion of pooled carbapenem-resistant for Enterobacterales was 3.6% (95% CI: 0.7%-16.4%).

Interpretation

This study suggests that ESCR-E carriage among children in SSA is frequent. Microbiology capacity and infection control must be scaled-up to reduce the spread of those multidrug-resistant microorganisms.

Funding

There was no funding source for this study.

Hospital prescribing patterns of antibiotics in Zambia using the WHO prescribing indicators post-COVID-19 pandemic: findings and implications

Background

Antimicrobial resistance (AMR) is a global public health problem that is fuelled by the inappropriate prescribing of antibiotics, especially those from the 'watch' and 'reserve' antibiotic lists. The irrational prescribing of antibiotics is particularly prevalent in developing countries, including Zambia. Consequently, there is a need to better understand prescribing patterns across sectors in Zambia as a basis for future interventions. This study evaluated the prescribing patterns of antibiotics using the WHO prescribing indicators alongside the 'access, watch and reserve' (AWaRe) classification system post-COVID pandemic at a faith-based hospital in Zambia.

Methods

A cross-sectional study was conducted from August 2023 to October 2023 involving the review of medical records at St. Francis' Mission Hospital in Zambia. A WHO-validated tool was used to evaluate antibiotic prescribing patterns alongside the AWaRe classification tool.

Results

Out of 800 medical records reviewed, 2003 medicines were prescribed. Each patient received an average of 2.5 medicines per prescription. Antibiotics were prescribed in 72.3% of encounters, of which 28.4% were injectable. The most frequently prescribed antibiotics were amoxicillin (23.4%-access), metronidazole (17.1%-access), ciprofloxacin (8%-watch) and ceftriaxone (7.4%-watch), with 77.1% overall from the 'access' list. Encouragingly, 96.5% of the medicines were prescribed by their generic names and 98% were from the Zambia Essential Medicines List.

Conclusions

There were high rates of antibiotic prescribing, including injectable antibiotics, which needs addressing going forward. It is crucial to implement targeted measures, including antimicrobial stewardship programmes, to improve future antibiotic prescribing in Zambia and reduce the risk of AMR.

Asymptomatic gastrointestinal carriage of multidrug-resistant carbapenemase-producing Enterobacteriaceae among children under five years in a Kenyan hospital

Objectives

Asymptomatic gastrointestinal carriage of carbapenem-resistant Enterobacteriaceae (CRE) is a threat to global health in developing countries with inadequate safe drinking water, poor hygiene, and weak antimicrobial stewardship; however, epidemiological data to guide CRE infection prevention and control is limited in these settings. We assessed asymptomatic CRE and carbapenem-producing Enterobacteriaceae (CPE) fecal carriage rates and associated risk factors among hospitalized children aged under 5 years.

Methods

We adopted a cross-sectional study at Mama Lucy Kibaki Hospital in Nairobi-City County, Kenya, between June and September 2022. We collected demographic and clinical characteristics using a structured questionnaire and clinical reports and analyzed stool/rectal swab samples by standard and automated bacteriological methods.

Results

Asymptomatic CRE and CPE fecal carriage rate was 2.25% (6/267), with six isolates recovered, predominated by Escherichia coli (33.33%) and Enterobacter cloacae subsp dissolvens (33.33%). Third-generation cephalosporin and ciprofloxacin resistance were highest in Citrobacter farmer and E. cloacae subsp cloacae. All CRE and CPE were multidrug-resistant, and except E. cloacae subsp cloacae, were 100% colistin-resistant.

Conclusions

Asymptomatic gastrointestinal carriage of multidrug-resistant-CRE among hospitalized children under 5 years, presents a substantial public health threat. This calls for continuous surveillance including molecular characterization of isolates, to inform infection prevention and antimicrobial stewardship adherence in line with local and global plans on AMR.

Source-tracking ESBL-producing bacteria at the maternity ward of Mulago hospital, Uganda

INTRODUCTION

Escherichia coli, Klebsiella pneumoniae and Enterobacter (EKE) are the leading cause of mortality and morbidity in neonates in Africa. The management of EKE infections remains challenging given the global emergence of carbapenem resistance in Gram-negative bacteria. This study aimed to investigate the source of EKE organisms for neonates in the maternity environment of a national referral hospital in Uganda, by examining the phenotypic and molecular characteristics of isolates from mothers, neonates, and maternity ward.

METHODS

From August 2015 to August 2016, we conducted a cross-sectional study of pregnant women admitted for elective surgical delivery at Mulago hospital in Kampala, Uganda; we sampled (nose, armpit, groin) 137 pregnant women and their newborns (n = 137), as well as health workers (n = 67) and inanimate objects (n = 70 -beds, ventilator tubes, sinks, toilets, door-handles) in the maternity ward. Samples (swabs) were cultured for growth of EKE bacteria and isolates phenotypically/molecularly investigated for antibiotic sensitivity, as well as β-lactamase and carbapenemase activity. To infer relationships among the EKE isolates, spatial cluster analysis of phenotypic and genotypic susceptibility characteristics was done using the Ridom server.

RESULTS

Gram-negative bacteria were isolated from 21 mothers (15%), 15 neonates (11%), 2 health workers (3%), and 13 inanimate objects (19%); a total of 131 Gram-negative isolates were identified of which 104 were EKE bacteria i.e., 23 (22%) E. coli, 50 (48%) K. pneumoniae, and 31 (30%) Enterobacter. Carbapenems were the most effective antibiotics as 89% (93/104) of the isolates were susceptible to meropenem; however, multidrug resistance was prevalent i.e., 61% (63/104). Furthermore, carbapenemase production and carbapenemase gene prevalence were low; 10% (10/104) and 6% (6/104), respectively. Extended spectrum β-lactamase (ESBL) production occurred in 37 (36%) isolates though 61 (59%) carried ESBL-encoding genes, mainly blaCTX-M (93%, 57/61) implying that blaCTX-M is the ideal gene for tracking ESBL-mediated resistance at Mulago. Additionally, spatial cluster analysis revealed isolates from mothers, new-borns, health workers, and environment with similar phenotypic/genotypic characteristics, suggesting transmission of multidrug-resistant EKE to new-borns.

CONCLUSION

Our study shows evidence of transmission of drug resistant EKE bacteria in the maternity ward of Mulago hospital, and the dynamics in the ward are more likely to be responsible for transmission but not individual mother characteristics. The high prevalence of drug resistance genes highlights the need for more effective infection prevention/control measures and antimicrobial stewardship programs to reduce spread of drug-resistant bacteria in the hospital, and improve patient outcomes.

Molecular epidemiology of enterically colonizing Escherichia coli with resistance against third-generation cephalosporins isolated from stool samples of European soldiers with concomitant diarrhea on deployment in Western African Mali

Extended spectrum beta-lactamases (ESBL) are frequently found in Enterobacterales isolates from Western Africa. However, information on the molecular epidemiology of regional ESBL-positive Enterobacterales strains is scarce. In order to provide epidemiological information, ESBL-positive Escherichia coli isolates from stool samples of European soldiers with diarrhea deployed to a field camp in Mali were subjected to whole-genome sequencing (Illumina MiSeq and Oxford Nanopore MinION) and antimicrobial susceptibility testing. With two exemptions, sequence-based analysis suggested an absence of transmission events between soldiers as indicated by a high genetic diversity of isolates and sequence types, confirming previous rep-PCR results. Third-generation cephalosporin resistance was associated with the presence of bla_CTX-M-15 genes with (n = 14) and without (n = 5) co-occurring bla_TEM-1b genes. Between 0 and 6 virulence and resistance plasmids per isolate were recorded. The detected resistance plasmids could be categorized into five types, which, in turn, share different sequence-identical segments, representing particular antimicrobial resistance gene-associated mobile genetic elements (MGEs). Phenotypic resistance rates within the 19 assessed isolates that showed distinguishable colony morphologies were 94.7% (18/19) against ampicillin-sulbactam and trimethoprim/sulfamethoxazole, 68.4% (13/19) against moxifloxacin, 31.6% (6/19) against ciprofloxacin, 42.1% (8/19) against gentamicin, 31.6% (6/19) against tobramycin, and 21.1% (4/19) against piperacillin-tazobactam and fosfomycin. Virulence-associated genes mediating infectious gastroenteritis were rarely detected. The gene aggR, which is characteristic for enteroaggregative E. coli, was only detected in one single isolate. In summary, we found a variety of different strains and clonal lineages of ESBL-carrying E. coli. Transmission either between soldiers or from common contaminated sources was demonstrated in two cases and played only a minor role in this military field camp, while there were indications that resistance gene bearing MGEs had been exchanged between antimicrobial resistance gene-(ARG-)carrying plasmids.

Molecular Epidemiology of Escherichia coli with Resistance against Third-Generation Cephalosporines Isolated from Deployed German Soldiers-A Retrospective Assessment after Deployments to the African Sahel Region and Other Sites between 2007 and 2016

Colonization and infection with bacteria with acquired antibiotic resistance are among the risks for soldiers on international deployments. Enterobacterales with resistance against third-generation cephalosporines are amongst the most frequently imported microorganisms. To contribute to the scarcely available epidemiological knowledge on deployment-associated resistance migration, we assessed the molecular epidemiology of third-generation cephalosporine-resistant Escherichia coli isolated between 2007 and 2016 from German soldiers after deployments, with a particular focus on the African Sahel region. A total of 51 third-generation cephalosporine-resistant E. coli isolated from 51 military returnees from deployment collected during the assessment period between 2007 and 2016 were subjected to short-read next-generation sequencing analysis. Returnees from the Sahel region (Djibouti, Mali, South Sudan, Sudan, Sudan, and Uganda) comprised a proportion of 52.9% (27/51). Repeatedly isolated sequence types according to the Warwick University scheme from returnees from the Sahel region were ST38, ST131, and ST648, confirming previous epidemiological assessments from various sub-Saharan African regions. Locally prevalent resistance genes in isolates from returnees from the Sahel region associated with third-generation resistance were bla_CTX-M-15, bla_CTX-M-27, bla_CTX-M-1, bla_TEM-169, bla_CTX-M-14, bla_CTX-M-99-like, bla_CTX-M-125, bla_SHV-12, and bla_DHA-1, while virulence genes were east1, sat, and tsh in declining order of frequency of occurrence each. In line with phenotypically observed high resistance rates for aminoglycosides and trimethoprim/sulfamethoxazole, multiple associated resistance genes were observed. A similar, slightly more diverse situation was recorded for the other deployment sites. In summary, this assessment provides first next-generation sequencing-based epidemiological data on third-generation cephalosporine-resistant E. coli imported by deployed German soldiers with a particular focus on deployments to the Sahel region, thus serving as a small sentinel. The detected sequence types are well in line with the results from previous epidemiological assessments in sub-Saharan Africa.

Concurrent Resistance to Carbapenem and Colistin Among Enterobacteriaceae Recovered From Human and Animal Sources in Nigeria Is Associated With Multiple Genetic Mechanisms

Resistance to last resort drugs such as carbapenem and colistin is a serious global health threat. This study investigated carbapenem and colistin resistance in 583 non-duplicate Enterobacteriaceae isolates utilizing phenotypic methods and whole genome sequencing (WGS). Of the 583 isolates recovered from humans, animals and the environment in Nigeria, 18.9% (110/583) were resistant to at least one carbapenem (meropenem, ertapenem, and imipenem) and 9.1% (53/583) exhibited concurrent carbapenem-colistin resistance. The minimum inhibitory concentrations of carbapenem and colistin were 2–32 μg/mL and 8 to >64 μg/mL, respectively. No carbapenem resistant isolates produced carbapenemase nor harbored any known carbapenemase producing genes. WGS supported that concurrent carbapenem-colistin resistance was mediated by novel and previously described alterations in chromosomal efflux regulatory genes, particularly mgrB (M1V) ompC (M1_V24del) ompK37 (I70M, I128M) ramR (M1V), and marR (M1V). In addition, alterations/mutations were detected in the etpA, arnT, ccrB, pmrB in colistin resistant bacteria and ompK36 in carbapenem resistant bacteria. The bacterial isolates were distributed into 37 sequence types and characterized by the presence of internationally recognized high-risk clones. The results indicate that humans and animals in Nigeria may serve as reservoirs and vehicles for the global spread of the isolates. Further studies on antimicrobial resistance in African countries are warranted.