Emergence of Carbapenem-Hydrolyzing Oxacillinases in Acinetobacter baumannii in Children from Croatia

Molecular epidemiology of carbapenemase encoding genes in A. baumannii-calcoaceticus complex infections in children: a systematic review

Background

Acinetobacter baumannii-calcoaeticus complex is the leader pathogen for the World Health Organization's list due to the escalating prevalence of multidrug-resistant strains. Insights into the molecular characterization of carbapenemase genes in A. baumannii-calcoaceticus complex infections among children are scarce. To address this gap, we conducted a systematic review to describe the molecular epidemiology of the carbapenemase genes in A. baumannii-calcoaceticus complex infections in the pediatric population.

Methods

Adhering to the PRISMA 2020 guidelines for reporting systematic reviews, we conducted a review of in chore bibliographic databases published in English and Spanish, between January 2020 and December 2022. All studies conducted in patients ≤6 years with molecular characterization of carbapenemase-encoding genes in A. baumannii-calcoaceticus infections were included.

Results

In total, 1129 cases were reviewed, with an overall carbapenem-resistance rate of 60.3%. A. baumannii-calcoaceticus was isolated from blood cultures in 66.6% of cases. Regionally, the Eastern Mediterranean exhibited the highest prevalence of carbapenem resistance (88.3%). Regarding the carbapenemase genes, blaKPC displayed an overall prevalence of 1.2%, while class B blaNDM had a prevalence of 10.9%. Class D blaOXA-23-like reported a prevalence of 64%, blaOXA-48 and blaOXA-40 had a prevalence of 33% and 18.1%, respectively. Notably, the Americas region showed a prevalence of blaOXA-23-like at 91.6%.

Conclusion

Our work highlights the high prevalence of carbapenem-resistant A. baumannii-calcoaceticus and class D carbapenemase genes in children. Of note the distribution of different carbapenemase genes reveals considerable variations across WHO regions. To enhance epidemiological understanding, further extensive studies in children are imperative.

Antimicrobial Susceptibility Among Gram-Negative Isolates in Pediatric Patients in Latin America, Africa-Middle East, and Asia From 2016-2020 Compared to 2011-2015: Results From the ATLAS Surveillance Study

BACKGROUND

Antimicrobial resistance (AMR) data in the pediatric population are limited, particularly in developing countries. This study assessed the AMR profile and key resistance phenotypes and genotypes for Gram-negative bacteria (GNB) isolates collected as part of the Antimicrobial Testing Leadership and Surveillance program from pediatric patients in Latin America, Africa-Middle East, and Asia in 2016-2020 versus 2011-2015.

METHODS

Minimum inhibitory concentrations by broth microdilution methodology were interpreted per the Clinical and Laboratory Standards Institute. European Committee on Antimicrobial Susceptibility Testing breakpoints were used for interpreting colistin activity. β-lactamase genes were screened by polymerase chain reaction and sequencing.

RESULTS

For Acinetobacter baumannii, low susceptibility (<60.0%) was observed for all antimicrobials, except colistin (≥92.9%), across regions and year periods. Ceftazidime-avibactam, amikacin, colistin, and meropenem were mostly active (78.6%-100.0%) against Enterobacter cloacae, Escherichia coli, and Klebsiella pneumoniae. For Pseudomonas aeruginosa, susceptibility to ceftazidime-avibactam, amikacin, and colistin was ≥85.9%. Among resistance phenotypes, carbapenem-resistant (CR, ≥44.8%) and difficult-to-treat resistant (DTR, ≥37.1%) rates were the highest in A. baumannii. A consistent increase in CR and DTR K. pneumoniae was noted across regions over time. Extended-spectrum β-lactamases (ESBL)-producing K. pneumoniae (32.6%-55.6%) were more frequent than ESBL-producing E. coli (25.3%-37.1%). CTX-M was the dominant ESBL among Enterobacterales. NDM-positive Enterobacterales species and VIM-positive P. aeruginosa were identified across regions.

CONCLUSIONS

This study identified high susceptibility to few agents for key GNB in pediatric patients. Continued surveillance of resistance phenotypes and genotypes at regional levels may help to guide appropriate treatment decisions.

Plant-derived nanotherapeutic systems to counter the overgrowing threat of resistant microbes and biofilms

Since antiquity, the survival of human civilization has always been threatened by the microbial infections. An alarming surge in the resistant microbial strains against the conventional drugs is quite evident in the preceding years. Furthermore, failure of currently available regimens of antibiotics has been highlighted by the emerging threat of biofilms in the community and hospital settings. Biofilms are complex dynamic composites rich in extracellular polysaccharides and DNA, supporting plethora of symbiotic microbial life forms, that can grow on both living and non-living surfaces. These enforced structures are impervious to the drugs and lead to spread of recurrent and non-treatable infections. There is a strong realization among the scientists and healthcare providers to work out alternative strategies to combat the issue of drug resistance and biofilms. Plants are a traditional but rich source of effective antimicrobials with wider spectrum due to presence of multiple constituents in perfect synergy. Other than the biocompatibility and the safety profile, these phytochemicals have been repeatedly proven to overcome the non-responsiveness of resistant microbes and films via multiple pathways such as blocking the efflux pumps, better penetration across the cell membranes or biofilms, and anti-adhesive properties. However, the unfavorable physicochemical attributes and stability issues of these phytochemicals have hampered their commercialization. These issues of the phytochemicals can be solved by designing suitably constructed nanoscaled structures. Nanosized systems can not only improve the physicochemical features of the encapsulated payloads but can also enhance their pharmacokinetic and therapeutic profile. This review encompasses why and how various types of phytochemicals and their nanosized preparations counter the microbial resistance and the biofouling. We believe that phytochemical in tandem with nanotechnological innovations can be employed to defeat the microbial resistance and biofilms. This review will help in better understanding of the challenges associated with developing such platforms and their future prospects.