Epidemiology, risk factors, and clinical outcomes of carbapenem-resistant Enterobacterales in Africa: A systematic review

One Health distribution of beta-lactamases in Enterobacterales in the United States: A systematic review and meta-analysis

BACKGROUND

The study aimed to review the beta-lactamase resistance genes detected in Enterobacterales from humans, animals, and the environment in the United States.

METHODS

We conducted a comprehensive search on PubMed, Web of Science, and Google Scholar for articles reporting beta-lactamase genes in the United States from 1981 to 22 April 2022, following the PRISMA protocol. Studies were evaluated based on predefined eligibility criteria, and both qualitative and quantitative analyses were conducted on the selected studies.

RESULTS

Of the 335 articles, a total of 169 different beta-lactamase genes, including narrow-spectrum, extended-spectrum, AmpC, and carbapenemase have been detected and reported in the United States, with human (137), animal (53), and environment (47). 22 genes (blaCMY-2, blaCTX-M-(1, 2, 9, 14, 15, 27, 32, 65), blaFOX-5, blaIMP-27, blaKPC-2, blaNDM-(1, 5), blaOXA-(1, 48), blaPSE-1, blaSHV-(1, 12), blaTEM-(1, 1A, 1B)) have been reported across animals, humans, and environment. Notably, blaCTX-M-15 was prevalent in E. coli isolates, with an overall pooled proportion of 10.7 %, varying between animals (8.6 %), humans (13.1 %), and the environment (0.8 %). Similarly, blaCMY-2 in E. coli isolates had an overall pooled proportion of 10.6 %, with distinctions in proportion among animals (1.6 %), humans (41.3 %), and the environment (16.2 %). The sequence type (ST131) was detected as the predominant, mainly associated with the blaCTX-M-15, with a pooled proportion of 56.9 %, varying from 14.3 % to 90 % across studies.

CONCLUSION

This study highlights the distribution of beta-lactamases in the United States, essential for understanding One Health and the molecular epidemiology of key beta-lactamases, especially extended-spectrum beta-lactamases and carbapenemases.

Epidemiology and Genetic Traits of Carbapenemase-Producing Enterobacterales: A Global Threat to Human Health

Carbapenemase-producing Enterobacterales (CPE) represent an important threat to global health, resulting in an urgent issue in clinical settings. CPE often exhibit a multidrug-resistant (MDR) phenotype, thus reducing the antimicrobial armamentarium, with few antibiotics retaining residual antimicrobial activity against these pathogens. Carbapenemases are divided into three classes (A, B, and D) according to the Ambler classification system. Among these, KPC (class A), NDM, VIM, IMP (class B), and OXA-48-like (class D) represent the most important carbapenemases in terms of diffusion and clinical impact. CPE diffusion has been observed worldwide, with current endemicity in multiple territories around the world. In this context, the clonal spread and plasmid-mediated transmission of carbapenemases have contributed to the global spread of CPE worldwide and to the diffusion of carbapenemases among different Enterobacterales species. In recent years, novel molecules showing excellent in vitro and in vivo activity have been developed against CPE. However, the recent emergence of novel traits of resistance to these molecules has already been reported in several cases, mitigating the initial promising results. This review aims to provide an updated description of the major classes of carbapenemases, their global distribution, and future perspectives to limit the diffusion of CPEs.

Molecular epidemiology of extended-spectrum beta-lactamases and carbapenemases-producing Shigella in Africa: a systematic review and meta-analysis

BACKGROUND

The treatment of Shigella infections has become a major challenge due to the emergence of multidrug-resistant Shigella. There is however insufficient knowledge regarding the molecular epidemiology of Shigella strains producing beta-lactamases in Africa. This systematic review investigated the scientific literature on the molecular epidemiology of extended-spectrum beta-lactamase (ESBL) and carbapenemases producing Shigella in Africa.

METHODS

Papers published in English and French from African countries on the molecular epidemiology of ESBL and carbapenemase producing Shigella from January 1999 to July 5, 2024 were reviewed. An extensive literature search was conducted through electronic databases including PubMed, Scopus, Web of Sciences, African Journals Online (AJOL) and Google scholar using specific keywords. The meta-analysis and forest plots of Shigella species, ESBL and carbapenemases genes were done using the comprehensive Meta-Analysis software. All data were analyzed using a binary random-effects model by the DerSimonian-Laird method at a 95% confidence interval.

RESULTS

Out of the 583 research articles, only 18 (3.1%) articles representing eleven countries were included in the meta-analysis. The overall pooled prevalence of ESBL and Carbapenem Resistant (CR)-producing Shigella was estimated as 41.2% (95% CI: 22.8-62.4; I2 = 93.7%, p < 0.05). The leading ESBL and CR-producing Shigella species reported in this review was Shigella flexneri, 34.5% (95% CI: 16.6-58.2; I2 = 94.9%, p < 0.05). ESBL and CR-producing Shigella sonnei was the least reported with estimated prevalence of 6.7% (95% CI: 3.4-13.2; I2 = 80.7%, p < 0.05). In this review, blaTEM, blaOXA-1, and blaCTX-M were the most prevalent genes in Africa with prevalence of 25.9% (95% CI: 13.9-43.2; I2 = 90.9%, p < 0.05), 25.7% (95% CI: 14.9-43.0; I2 = 93.7%, p < 0.05), and 10.8% (95% CI: 4.5-23.4; I2 = 85.6%, p < 0.05) respectively. The prevalence of Carbapenemases genes on the other hand was low, reported as 0.8% (95% CI: 0.2-10.3; I2 = 51.4%; p < 0.05) for blaNDM, 1.1% for blaKPC, and 0.5% for blaIMP.

CONCLUSION

This study highlighted Shigella flexneri as the most prevalent ESBL and CR-producing Shigella species found in various African countries. The findings from this review indicate blaTEM, blaOXA-1 and blaCTX-M as the most prevalent genes in Africa while carbapenemases are least prevalent. The findings from the study suggest that ESBL and CR-producing Shigella pose a significant public health threat in Africa. Effective antimicrobial resistance (AMR) surveillance strategies are needed to improve the management and treatment of Shigella infections in Africa.

Carbapenem resistance in gram-negative pathogens in an Iranian hospital: high prevalence of OXA-type carbapenemase genes

BACKGROUND

The widespread dissemination of carbapenem- resistant gram-negative bacteria poses a significant threat to global public health.

PURPOSE

This study aimed to investigate the prevalence of carbapenem resistance in gram-negative bacteria isolated from patients at the Children's Medical Center Hospital, Tehran, Iran, to understand the molecular mechanisms underlying this resistance.

METHODS

During the period spanning from June 2019 to June 2020, 777 gram-negative bacterial strains were isolated. Antibiotic susceptibility testing was performed according to Clinical and Laboratory Standards Institute. Polymerase chain reaction was used to detect carbapenem resistance genes including bla OXA23, bla OXA24, bla OXA48, bla OXA51, bla OXA58, bla OXA143, bla KPC, bla IMP, bla VIM, and bla NDM.

RESULTS

Among the total bacterial isolates, 141 (18.1%) exhibited carbapenem resistance. Escherichia coli was the most prevalent (57.4%), followed by Klebsiella pneumoniae (11.3%), and Acinetobacter baumannii (10.6%). Other notable contributors included Enterobacter spp. (5.7%), Salmonella spp. (3.5%), and Stenotrophomonas maltophilia (2.8%). Citrobacter spp., Proteus mirabilis, and Pseudomonas aeruginosa contributed to the distributions of 2, 1, and 3 isolates, respectively. Notably, bla OXA48 showed the highest prevalence (33%), followed by bla OXA143 and bla OXA5 8 (27% and 24%, respectively). In addition, bla OXA24 was present in 11% of the total isolates, bla OXA23 in 10%, and bla NDM in 10%, whereas bla KPC, bla VIM, and bla IMP were not detected.

CONCLUSION

Our study highlights the prevalence of carbapenemase- producing gram-negative isolates among pediatric patients. Notable resistance patterns, especially in K. pneumoniae and E. coli, underline the urgent need for proactive interventions, including appropriate antibiotic prescription practices and strengthening of antibiotic stewardship programs.

Epidemiological and molecular characteristics of carbapenem-resistant Klebsiella pneumoniae from pediatric patients in Henan, China

PURPOSE

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is an emerging global threat, whereas its epidemiological characteristics in children are rarely reported. This study aims to analyze clinical and epidemiological characteristics of CRKP from children in Henan, China.

METHODS

CRKP strains were isolated from pediatric patients, and the antimicrobial susceptibility of CRKP was determined using broth microdilution methods. The epidemiological characteristics of CRKP, including specimen sources, clinical data, carbapenemase types, virulence factors, MLST and PBRT typing were analyzed.

RESULTS

In total, 108 CRKP isolates were isolated from specimens including sputum, blood and urine, mainly from preterm pediatric department and internal medical intensive care unit (ICU). Newborns and staying in the ICU were risk factors for crude mortality. 107 isolates exhibited a multi-drug resistant (MDR) phenotype, and one isolate was extensively drug-resistant (XDR). Bacterial susceptibility to colistin, tigecycline and trimethoprim/sulfamethoxazole was 98.10%, 78.50% and 91.43%, respectively. Carbapenemase blaKPC (86.11%) was predominant, followed by blaNDM (5.56%) and blaIMP (2.78%). Two strains co-harbored blaKPC-blaNDM, one had blaKPC-blaIMP, whereas three isolates did not carry any of the analyzed carbapenemase genes. All strains possessed fimH, and 98% of the isolates possessed mrkD. Hypervirulent factors rmpA2 and iucA showed high positive rates (71.30% and 49.07%), with 48.15% of strains containing both genes. MLST analysis identified nine distinct sequence types (STs), with ST11 (82.41%) being the most common, followed by ST2154 (4.63%) and ST307 (3.70%). PBRT analysis revealed IncFII (85.19%) as the most prevalent plasmid.

CONCLUSION

In summary, this study reported the epidemiological features of CRKP in pediatric patients in Henan, China, highlighting the high prevalence of multi-drug-resistant and hypervirulent strains, and underscoring the significance of continuous surveillance.

High drug-pathogen mismatch in the management of invasive carbapenem-resistant Enterobacteriaceae infections at a tertiary hospital in Nigeria

Objectives

This study aims to provide lacking data on antibiotics and treatment strategies used in the management of carbapenem-resistant Enterobacteriaceae (CRE) infections in Nigeria.

Methods

A cross-sectional study was carried out at the University College Hospital in Ibadan. CRE isolated from routine culture of specimens from hospitalized patients from December 2021 to September 2022 was identified. Treatment information and other data were collected from the patients' medical records.

Results

The hospital laboratory isolated CRE from 55 patients during the study period and 27 (49.1%) of them had data available for the study. The most frequently isolated CRE was Klebsiella spp. (13 of 27, 48.1%). Of the 24 patients who received empiric antibiotics, only two (8.3%) of their CRE isolates were susceptible. After receiving culture results, 18 (66.7%) patients were treated with at least one antibiotic, to which resistance was documented. Only three (11.1%) patients overall commenced or remained on an antibiotic, to which their CRE isolate was susceptible.

Conclusions

Despite culture data, we found a high prevalence of drug-pathogen mismatch in CRE treatment, including new or persistent use of antibiotics, to which resistance was documented. Antimicrobial stewardship efforts need to be strengthened to specifically address CRE treatment and effective antibiotics need to be made accessible.

Risk Factors and Outcomes of Patients Colonized with KPC and NDM Carbapenemase-Producing Enterobacterales

Carbapenemase-producing enterobacterales (CPE) poses an increasing threat in hospitals worldwide. Recently, the prevalence of different carbapenemases conferring carbapenem resistance in enterobacterales changed in our country, including an increase in New Delhi Metallo-beta-lactamase (NDM)-CPE. We conducted a comparative historical study of adult patients colonized with Klebsiella pneumoniae carbapenemase (KPC)-CPE (July 2016 to June 2018, a historical cohort) vs. NDM-CPE (July 2016 to January 2023). We identified patients retrospectively through the microbiology laboratory and reviewed their files, extracting demographics, underlying diseases, Charlson Comorbidity Index (CCI) scores, treatments, and outcomes. This study included 228 consecutive patients from whom a CPE rectal swab screening was obtained: 136 NDM-CPE positive and 92 KPC-CPE positive. NDM-CPE-colonized patients had a shorter hospitalization length and a significantly lower 30-day post-discharge mortality rate (p = 0.002) than KPC-CPE-colonized patients. Based on multivariate regression, independent risk factors predicting CPE-NDM colonization included admission from home and CCI < 4 (p < 0.001, p = 0.037, respectively). The increase in NDM-CPE prevalence necessitates a modified CPE screening strategy upon hospital admission tailored to the changing local CPE epidemiology. In our region, the screening of younger patients residing at home with fewer comorbidities should be considered, regardless of a prior community healthcare contact or hospital admission.

Drug Discovery in the Field of β-Lactams: An Academic Perspective

β-Lactams are the most widely prescribed class of antibiotics that inhibit penicillin-binding proteins (PBPs), particularly transpeptidases that function in peptidoglycan synthesis. A major mechanism of antibiotic resistance is the production of β-lactamase enzymes, which are capable of hydrolyzing β-lactam antibiotics. There have been many efforts to counter increasing bacterial resistance against β-lactams. These studies have mainly focused on three areas: discovering novel inhibitors against β-lactamases, developing new β-lactams less susceptible to existing resistance mechanisms, and identifying non-β-lactam inhibitors against cell wall transpeptidases. Drug discovery in the β-lactam field has afforded a range of research opportunities for academia. In this review, we summarize the recent new findings on both β-lactamases and cell wall transpeptidases because these two groups of enzymes are evolutionarily and functionally connected. Many efforts to develop new β-lactams have aimed to inhibit both transpeptidases and β-lactamases, while several promising novel β-lactamase inhibitors have shown the potential to be further developed into transpeptidase inhibitors. In addition, the drug discovery progress against each group of enzymes is presented in three aspects: understanding the targets, screening methodology, and new inhibitor chemotypes. This is to offer insights into not only the advancement in this field but also the challenges, opportunities, and resources for future research. In particular, cyclic boronate compounds are now capable of inhibiting all classes of β-lactamases, while the diazabicyclooctane (DBO) series of small molecules has led to not only new β-lactamase inhibitors but potentially a new class of antibiotics by directly targeting PBPs. With the cautiously optimistic successes of a number of new β-lactamase inhibitor chemotypes and many questions remaining to be answered about the structure and function of cell wall transpeptidases, non-β-lactam transpeptidase inhibitors may usher in the next exciting phase of drug discovery in this field.