Co-existence of extended-spectrum β-lactamases blaCTX-M-9 and blaCTX-M-15 genes in Salmonella species isolated from febrile and diarrhoeagenic patients in Lagos, Nigeria: a cross-sectional study

High prevalence of carbapenem-resistant Enterobacterales (CRE) in human samples from Nigeria: A systematic review and meta-analysis

Objectives

The rise in Carbapenem-resistant Enterobacterales (CRE) is perturbing. To curb the menace of CRE, a comprehensive understanding of its prevalence and epidemiology is crucial. As varying reports abound, the true prevalence of CRE in Nigeria remains unknown. Here, we conducted a systematic review and meta-analysis following standard guidelines to assess the situation of CRE in Nigeria.

Methods

We searched electronic databases including Pubmed, ScienceDirect, Scopus, Web of Science, and Google Scholar for articles providing information on CRE in Nigeria. The data gathered were analyzed using OpenMeta Analyst and Comprehensive Meta-Analysis software. The random-effect model was employed to calculate pooled resistance to carbapenem antibiotics.

Results

From 321 retrieved records, 57 were finally included. The studies were predominantly from the South-West region (n = 19). Escherichia coli and Klebsiella pneumoniae were the most frequently tested Enterobacterales among the included studies. The pooled prevalence estimate for imipenem resistance among CRE was 11.2 % (95 % CI: 7.9-15.7). Meropenem resistance had an estimate of 13.5 % (95 % CI: 9.1-19.6), whereas ertapenem and doripenem were estimated at 17.0 % (95 % CI: 9.9-27.7) and 37.9 % (95 % CI: 15.0-67.8), respectively. High heterogeneity (I 2 >85 %, p < 0.001) was observed for the estimates. The highest resistance rate to imipenem (28.4 %), meropenem (37.2 %) and ertapenem (46.5 %) were observed for the South-South region. Based on specific CRE genera, Morganella sp. was the most resistant (37.0 %) while Escherichia sp. was the least (9.4 %). Our analyses also revealed a progressive increase in resistance to carbapenem antibiotics over the years.

Conclusion

This study highlights carbapenem resistance as a concern in Africa's most populous nation, underscoring the need for proactive measures to address and mitigate the threat of CRE.

Characterization of nontyphoidal Salmonella strains from a tertiary hospital in China: serotype diversity, multidrug resistance, and genetic insights

Objective

Nontyphoidal Salmonella is a significant public health concern due to its ability to cause foodborne illnesses worldwide. This study aims to characterize the nontyphoidal Salmonella strains isolated from patients in China.

Methods

A total of 19 nontyphoidal Salmonella strains were characterized through serovar identification, antimicrobial susceptibility testing (AST), biofilm formation assessment. Genetic relatedness was determined using pulsed-field gel electrophoresis (PFGE). WGS was employed to decipher the resistance mechanism and to contextualize the S. serovar Mbandaka strains among previously sequenced isolates in China. The biofilm associated mrkA gene was examined by PCR.

Results

The predominant serovar identified was S. Enteritidis, followed by S. Mbandaka, S. Thompson, S. Livingston, S. Alachua, and S. Infantis. PFGE analysis indicated a notable genetic similarity among the S. Mbandaka isolates. Phylogenetic analysis suggested that these strains were likely derived from a single source that had persisted in China for over five years. One multidrug resistance (MDR) S. Enteritidis isolate carried a highly transferable IncB/O/K/Z plasmid with bla CTX-M-15. One S. Thompson strain, harboring the mrkABCDF operon in an IncX1 plasmid, isolated from cutaneous lesions, demonstrated robust biofilm formation. However, no mrkABCDF loci were detected in other strains.

Conclusion

Our study emphasizes the importance of persisted surveillance and prompt response to Salmonella infections to protect public health. The dissemination of bla CTX-M-15-harboring IncB/O/K/Z plasmid and the spread of virulent mrkABCDF operon among Salmonella in China and other global regions warrant close monitoring.