Deciphering Multidrug-Resistant Acinetobacter baumannii from a Pediatric Cancer Hospital in Egypt

Evolution of an extensively antibiotic resistant sublineage of lineage 1 of GC1 Acinetobacter baumannii

The multiply antibiotic-resistant lineage 1 of Acinetobacter baumannii global clone 1 (GC1) emerged in the 1970s, and subsequently more extensively resistant sublineages have emerged. Here, we examined the evolution of the extensively resistant MRSN56 sublineage and showed it is characterised by insertions carrying resistance genes at specific chromosomal positions. An evolved form of the sublineage carries KL17 replacing KL1 at the capsule locus and includes an additional integrative element Aci-IE1 carrying further resistance genes including blaNDM. Further members of the modified sublineage (isolated 2014-2021) identified among publicly available genomes were from several countries and appear to have replaced the original form (2007-2010). Some KL17 type isolates had acquired even more resistance genes including blaPER. The blaNDM and blaPER genes contribute to reduced susceptibility to cefiderocol and/or sulbactam/durlobactam. The phylogeny indicated that separation of the sublineage into KL1 and KL17 groups coincided with the KL switch and Aci-IE1 was acquired later.

Molecular Identification of OXA Carbapenemase-Encoding Genes in Acinetobacter baumannii Isolated from Patients in Critical Care in Egypt

Background: The emergence of carbapenem-resistant Acinetobacter baumannii (CRAB) in hospitals, particularly within critical care units, has garnered substantial global concern. CRAB commonly arises from the degradation by various ß-lactamases. Objective: We aimed to assess OXA-type carbapenemases in clinical isolates of A. baumannii obtained from an Egyptian tertiary care facility. Patients and Methods: This study examined 25 distinct A. baumannii strains collected from various clinical samples of patients in intensive care unit. Bacterial identification was conducted utilizing both traditional methods and the Vitek2 system. Antibiotic resistance profiles were assessed according to the European Committee on Antimicrobial Susceptibility Testing standards using the Vitek2 Compact automated system. Additionally, multiplex real-time polymerase chain reaction was used to identify the presence of blaOXA23, blaOXA24, blaOXA51, and blaOXA58 carbapenemase genes. Colistin susceptibility was assessed utilizing the broth microdilution method. Results: Carbapenem resistance was identified in 100% of the studied isolates. The blaOXA51 gene was detected in all A. baumannii strains. The gene blaOXA23 was identified in 22 strains (88%), whereas blaOXA24 and blaOXA58 were present in 15 strains (60%). All isolates, except one, co-harbored two or more OXA encoding genes. Colistin resistance was detected in 4 of 25 strains (16%). Conclusion: Our findings demonstrate the widespread distribution of CRAB isolates that co-harbor multiple carbapenemase-encoding genes. Molecular epidemiological studies and the surveillance of antibiotic resistance profiles may aid in identifying and tracing the origins of resistant bacteria, thereby limiting their spread.

Prevalence of colistin-resistant Enterobacteriaceae isolated from clinical samples in Africa: a systematic review and meta-analysis

BACKGROUND

Antimicrobial resistance among Enterobacteriaceae poses a significant global threat, particularly in developing countries. Colistin, a critical last-resort treatment for infections caused by carbapenem-resistant and multidrug-resistant strains, is increasingly facing resistance due to inappropriate use of colistin and the spread of plasmid-mediated resistance genes. Despite the significance of this issue, comprehensive and updated data on colistin resistance in Africa is lacking. Thus, the current study was aimed to determine the pooled prevalence of colistin-resistant Enterobacteriaceae in Africa.

METHODS

A systematic search was conducted across PubMed, Scopus, ScienceDirect, and Google Scholar to identify relevant studies. Forty-one studies reporting on the prevalence of colistin resistance in Enterobacteriaceae isolates from clinical specimens in Africa were included in the analysis. Stata 17 software was used to calculate the pooled prevalence of colistin resistance, employing a random-effects model to determine the event rate of resistance. Heterogeneity across studies was assessed using the I2 statistic, and publication bias was evaluated using Egger's test. Subgroup analyses were performed to address any identified heterogeneity.

RESULTS

This systematic review analyzed the colistin resistance profile of 9,636 Enterobacteriaceae isolates. The overall pooled prevalence of colistin resistance was 26.74% (95% CI: 16.68-36.80). Subgroup analysis by country revealed significant variability in resistance rates, ranging from 0.5% in Djibouti to 50.95% in South Africa. Species-specific prevalence of colistin resistance was as follows: K. pneumoniae 28.8% (95% CI: 16.64%-41.05%), E. coli 24.5% (95% CI: 11.68%-37.3%), Proteus spp. 50.0% (95% CI: 6.0%-106.03%), and Enterobacter spp. 1.22% (95% CI: -0.5%-3.03%). Analysis based on AST methods revealed significant differences in colistin resistance rates (p = 0.001). The resistance rates varied between 12.60% for the disk diffusion method and 28.0% for the broth microdilution method. Additionally, a subgroup analysis of clinical specimens showed significant variation (p < 0.001) in colistin resistance. Stool specimen isolates had the highest resistance rate at 42.0%, while blood specimen isolates had a much lower resistance rate of 3.58%.

CONCLUSIONS

Colistin resistance in Enterobacteriaceae is notably high in Africa, with significant variation across countries. This underscores the urgent need for effective antimicrobial stewardship, improved surveillance, and the development of new antibiotics.

3-Hydroxybenzoic acid inhibits the virulence attributes and disrupts biofilm production in clinical isolates of Acinetobacter baumannii

PURPOSE

Acinetobacter baumannii (A. baumannii) is an emerging global public health threat owing to its ability to form biofilms. Here, we evaluated 3-hydroxybenzoic acid (3-HBA), a promising organic compound, for its ability to disrupt biofilm formation and virulence attributes in clinical isolates of A. baumannii.

MATERIALS AND METHODS

The effect of 3-HBA on A. baumannii was assessed by determining the minimum inhibitory concentration (MIC) and certain other in vitro investigations viz., extracellular polymeric substance (EPS) estimation, crystal violet staining assay, motility assay, and the hydrogen peroxide (H2O2) assay to examine its impact on bacterial virulence. Biofilm formation was also evaluated at the air-liquid interface. In situ visualization investigations were employed to confirm biofilm dispersion at the lowest effective concentration. The cytotoxic effects of 3-HBA on MCF-7 cells were investigated using the MTT assay.

RESULTS

At a sub-inhibitory concentration of 0.078 mg/mL, 3-HBA reduced biofilm formation in A. baumannii LSAB-04 and A. baumannii LSAB-06 by 61.22% and 59.21%, respectively, and decreased EPS production by 64% in LSAB-04 and 58.31% in LSAB-06. Microscopic examination confirmed significant biofilm dispersion. 3-HBA also significantly impaired swarming motility and increased their sensitivity to H2O2. The MTT assay showed a dose-dependent decrease in MCF-7 cell viability (43.67%) at a concentration of 0.078 mg/mL.

CONCLUSION

Our findings underscore the likely role of 3-HBA as a promising A. baumannii biofilm-disrupting agent. Further, by downplaying against the virulence factors of A. baumannii, 3-HBA could be a compelling alternative to conventional antibiotics that however requires to be investigated.

Microbiological Profiles and Resistance Patterns in Pediatrics With Cancer: An 8-Year Study at a Comprehensive Cancer Center in Jordan

INTRODUCTION

Infections impact morbidity and mortality in pediatric cancer patients, yet limited studies have assessed the microbiological profiles and susceptibility patterns of pathogenic bacteria in this population. This study aimed to investigate bacterial profiles and temporal resistance changes in pediatrics with cancer.

METHODS

We identified positive cultures between January 2015 and December 2022 for pediatric patients diagnosed with cancer at age < 18 years. Electronic records provided patient demographics, microbiological profiles and resistance patterns. Using "R" programming, the dataset was refined, selecting patients' first isolate within a 30-day period, and categorizing strains based on multidrug-resistant (MDR) and extensively drug-resistant (XDR) predefined criteria. Additionally, we analyzed changes in resistance patterns over the study period.

RESULTS

Out of 1215 patients, 2992 bacterial isolates were reported, with 66% being Gram-negative bacteria. Urine was the most common site of infection, representing 48% of cases. Among these, 42% were MDR and 2% XDR. MDR prevalence was 45% for Escherichia coli, 21% for Klebsiella pneumonia, and 14% for Staphylococcus aureus. Acinetobacter baumannii and Pseudomonas aeruginosa displayed XDR at 79% and 21%, respectively. Methicillin-resistant S. aureus decreased from 71% in 2015 to 54% in 2022. MDR Klebsiella pneumonia peaked in 2021. MDR Pseudomonas aeruginosa decreased from 44% in 2015 to 16% in 2022.

CONCLUSION

Drug resistance was detected in 50% of the isolates with most being Gram-negative and MDR. Further research is needed to identify risk factors for resistance, aiming to refine empiric antimicrobial therapy.

Genomic characterization and identification of multiple drug resistance genes in clinical isolates of Acinetobacter baumannii through whole genome sequencing

BACKGROUND

Acinetobacter baumannii is a notorious nosocomial pathogen universally in healthcare settings. Its natural competent characteristics for genetic recombination are responsible for acquired antibiotic resistance and render it untreatable through commonly used antibiotics. Hence, characterizing the A. baumannii genomes for multidrug resistance carriage is of paramount importance. The study aimed to characterize the whole genome of clinical isolates of A. baumannii to identify specifically the types of antibiotic resistance genes, drug classes and mobile genetic elements. We also aimed to determine the significant multi-locus sequence tags (MLSTs). The phylogeny of the isolates was established with other clinical strains distributed globally.

METHODS AND RESULTS

Fifteen clinical isolates (isolated from tracheal secretion, urine and bronchoalveolar lavage) were subjected to whole genome sequencing. Raw sequences were assembled using SPAdes and species were identified using KmerFinder 3.2. The assembled genomes were annotated using the Prokka v1.14.6. Resfinder 4.6.0 was used to determine antibiotic resistance genes. The sequences were aligned against seven housekeeping genes aka sequence tags (STs) available within the MLST database (v 2.0.9). MobileGeneticElement finder (v1.0.3) were used for profiling mobile genetic elements associated with the antibiotic resistance genes. The genomes of nosocomial A. baumannii were assembled with an average N50 of 23,480 and GC content of 38%. There were approximately 3700 CDs, 53 tRNA and 3 rRNA. About 80% of the isolates were ST2 type. The genomes possessed antibiotic resistance genes (n = 24) belonging to 17 drug classes. The predicted phenotype was multidrug resistant. Among the mobile genetic elements, 12 insertion sequences and 2 composite transposons were also found. The mode of antibiotic resistance was mostly through antibiotic inactivation in all the isolates.

CONCLUSIONS

The results imply the occurrence of multidrug resistant genes in clinical isolates of A. baumannii strains in the healthcare settings of Kuwait. A more comprehensive survey should be undertaken for antimicrobial resistance monitoring on a regular basis for surveillance, contact tracing, and potential mitigation in clinical settings.

Antimicrobial resistance and virulence factors analysis of a multidrug-resistant Acinetobacter baumannii isolated from chickens using whole-genome sequencing

Multidrug-resistant (MDR) Acinetobacter baumannii (A. baumannii) is currently recognized not only as a significant nosocomial pathogen but also is an emerging bacterial infection in food-producing animals, posing a critical threat to global health. However, this is a hindrance to detailed bioinformatic studies of MDR A. baumannii of chicken origin due to the lack of its complete genome sequence. Here, we report whole-genome sequencing analysis of MDR A. baumannii Y03 isolated from chickens. The Y03 genome consists of 1 circular chromosome and 4 circular plasmids, The Y03 chromosome harbors 41 antimicrobial resistance genes conferring resistance to major classes of antibiotics, including β-lactams, phenicols, macrolides, lincosamides, aminoglycosides, and nitrofurans, as well as 135 virulence factors involved in effector delivery system, immune modulation, adherence, stress survival, biofilm, exotoxin, and nutritional/metabolic factor. The in vivo infection experiments certificated that Y03 was virulent to chickens. Meanwhile, we used PCR amplification method to detect 10 antimicrobial resistance genes including abeM, adeB, adeH, adeK, blaapmC, blaOXA-90, catB9, macB, folP, and parE, as well as 14 virulence genes including lpxC, pilO, fimT, ompA, basA, bauA, gspL, csu, pgaC, plc2, tssA, tviB, bap, and vgrG. Whole-genome sequencing analysis revealed that Y03 contained 46 horizontal gene transfer elements, including 11 genomic islands, 30 transposons, and 5 prophages, as well as 518 mutations associated with reduced virulence and 44 mutations resulting in loss of pathogenicity. Furthermore, there were 22 antibiotic targets and 28 lethal mutations on the Y03 chromosome that could be used as potential targets to prevent, control, and treat infections caused by MDR A. baumannii Y03. Therefore, this study contributes to the development of strategies for the prevention, control, and treatment of A. baumannii infections and their spread in chickens.

Epidemiology and antimicrobial resistance trends of Acinetobacter species in the United Arab Emirates: a retrospective analysis of 12 years of national AMR surveillance data

INTRODUCTION

Acinetobacter spp., in particular A. baumannii, are opportunistic pathogens linked to nosocomial pneumonia (particularly ventilator-associated pneumonia), central-line catheter-associated blood stream infections, meningitis, urinary tract infections, surgical-site infections, and other types of wound infections. A. baumannii is able to acquire or upregulate various resistance determinants, making it frequently multidrug-resistant, and contributing to increased mortality and morbidity. Data on the epidemiology, levels, and trends of antimicrobial resistance of Acinetobacter spp. in clinical settings is scarce in the Gulf Cooperation Council (GCC) and Middle East and North Africa (MENA) regions.

METHODS

A retrospective 12-year analysis of 17,564 non-duplicate diagnostic Acinetobacter spp. isolates from the United Arab Emirates (UAE) was conducted. Data was generated at 317 surveillance sites by routine patient care during 2010-2021, collected by trained personnel and reported by participating surveillance sites to the UAE National AMR Surveillance program. Data analysis was conducted with WHONET.

RESULTS

Species belonging to the A. calcoaceticus-baumannii complex were mostly reported (86.7%). They were most commonly isolated from urine (32.9%), sputum (29.0%), and soft tissue (25.1%). Resistance trends to antibiotics from different classes during the surveillance period showed a decreasing trend. Specifically, there was a significant decrease in resistance to imipenem, meropenem, and amikacin. Resistance was lowest among Acinetobacter species to both colistin and tigecycline. The percentages of multidrug-resistant (MDR) and possibly extensively drug-resistant (XDR) isolates was reduced by almost half between the beginning of the study in 2010 and its culmination in 2021. Carbapenem-resistant Acinetobacter spp. (CRAB) was associated with a higher mortality (RR: 5.7), a higher admission to ICU (RR 3.3), and an increased length of stay (LOS; 13 excess inpatient days per CRAB case), as compared to Carbapenem-susceptible Acinetobacter spp.

CONCLUSION

Carbapenem-resistant Acinetobacter spp. are associated with poorer clinical outcomes, and higher associated costs, as compared to carbapenem-susceptible Acinetobacter spp. A decreasing trend of MDR Acinetobacter spp., as well as resistance to all antibiotic classes under surveillance was observed during 2010 to 2021. Further studies are needed to explore the reasons and underlying factors leading to this remarkable decrease of resistance over time.

Phenotypic and Genotypic Analysis of Bacterial Pathogens Recovered from Patients Diagnosed with Fever of Unknown Origin in Egypt

Fever of unknown origin (FUO) is a medical term describing fever that lasts for at least three weeks without a diagnosis being reached after extensive diagnostic evaluation. Therefore, this study aimed to identify the common pathogens causing FUO in patients admitted to Abbasia Fever Hospital in Egypt from January 2020 to December 2022, their antimicrobial susceptibility profiles, and associated resistance genes. The study also aimed to investigate the burden of multidrug-resistant (MDR) pathogens and the priority pathogens nominated by the World Health Organization (WHO) for posing the greatest threat to human health due to antibiotic resistance. During the study period, about 726 patients were diagnosed with FUO. After extensive investigations, the cause of the FUO was found to be infectious diseases in 479/726 patients (66.0%). Of them, 257 patients had positive bacterial cultures, including 202 Gram-negative isolates that comprised Klebsiella pneumoniae (85/202; 42.1%), Escherichia coli (71/202; 35.1%), Acinetobacter baumannii (26/202; 12.9%), and Pseudomonas aeruginosa (14/202; 6.9%) and 55 Gram-positive isolates, including Staphylococcus aureus (23/55; 41.8%), Streptococcus pneumoniae (7/55; 12.7%), and Enterococcus spp. (25/55; 45.5%). The MDR phenotype was shown by 68.3% and 65.5% of the Gram-negative and Gram-positive isolates, respectively. Carbapenem resistance (CR) was shown by 43.1% of the Gram-negative isolates. Of the 23 S. aureus isolates obtained from research participants, 15 (65.2%) were methicillin-resistant S. aureus (MRSA). A high-level aminoglycoside resistance (HLAR) phenotype was found in 52.0% of the Enterococcus sp. isolates. The PCR screening of resistance genes in the MDR isolates showed that blaOXA-48 was the most prevalent (84%) among the carbapenemase-coding genes, followed by blaVIM (9%) and then blaIMP (12%). The ESBL-coding genes blaTEM, blaCTX-M,aac(6')-Ib, and blaSHV, were prevalent in 100%, 93.2%, 85,% and 53.4% of the MDR isolates, respectively. This study updates the range of bacteria that cause FUO and emphasizes the burden of multidrug resistance and priority infections in the region. The obtained data is of relevant medical importance for the implementation of evidence-based antimicrobial stewardship programs and tailoring existing empirical treatment guidelines.

Acinetobacter baumannii Global Clone-Specific Resistomes Explored in Clinical Isolates Recovered from Egypt

Acinetobacter baumannii (A. baumannii) is a highly problematic pathogen with an enormous capacity to acquire or upregulate antibiotic drug resistance determinants. The genomic epidemiology and resistome structure of 46 A. baumannii clinical isolates were studied using whole-genome sequencing. The isolates were chosen based on reduced susceptibility to at least three classes of antimicrobial compounds and were initially identified using MALDI-TOF/MS, followed by polymerase chain reaction amplification of bla_OXA-51-like genes. The susceptibility profiles were determined using a broth microdilution assay. Multi-, extensive-, and pan-drug resistance was shown by 34.8%, 63.0%, and 2.2% of the isolates, respectively. These were most susceptible to colistin (95.7%), amikacin, and trimethoprim/sulfamethoxazole (32.6% each), while only 26.1% of isolates were susceptible to tigecycline. In silico multi-locus sequence typing revealed 8 Pasteur and 22 Oxford sequence types (STs) including four novel STs (ST^Oxf 2805, 2806, 2807, and 2808). The majority of the isolates belonged to Global Clone (GC) 2 (76.4%), GC5 (19.6%), GC4 (6.5%), GC9 (4.3%), and GC7 (2.2%) lineages. An extensive resistome potentially conferring resistance to the majority of the tested antimicrobials was identified in silico. Of all known carbapenem resistance genes, bla_OXA-23 was carried by most of the isolates (69.6%), followed by ISAba1-amplified bla_ADC (56.5%), bla_NDM-1 and bla_GES-11 (21.7% each), and bla_GES-35 (2.2%) genes. A significant correlation was found between carbapenem resistance and carO mutations, which were evident in 35 (76.0%) isolates. A lower proportion of carbapenem resistance was noted for strains possessing both bla_OXA-23- and bla_GES-11. Amikacin resistance was most probably mediated by armA, aac(6')-Ib9, and aph(3')-VI, most commonly coexisting in GC2 isolates. No mutations were found in pmrABC or lpxACD operons in the colistin-resistant isolates. Tigecycline resistance was associated with adeS (N268Y) and baeS (A436T) mutations. While the lineage-specific distribution of some genes (e.g., bla_ADC and bla_OXA-51-like alleles) was evident, some resistance genes, such as bla_OXA-23 and sul1, were found in all GCs. The data generated here highlight the contribution of five GCs in A. baumannii infections in Egypt and enable the comprehensive analysis of GC-specific resistomes, thus revealing the dissemination of the carbapenem resistance gene bla_OXA-23 in isolates encompassing all GCs.

CRISPR-Based Gene Editing in Acinetobacter baumannii to Combat Antimicrobial Resistance

Antimicrobial resistance (AMR) poses a significant threat to the health, social, environment, and economic sectors on a global scale and requires serious attention to addressing this issue. Acinetobacter baumannii was given top priority among infectious bacteria because of its extensive resistance to nearly all antibiotic classes and treatment options. Carbapenem-resistant A. baumannii is classified as one of the critical-priority pathogens on the World Health Organization (WHO) priority list of antibiotic-resistant bacteria for effective drug development. Although available genetic manipulation approaches are successful in A. baumannii laboratory strains, they are limited when employed on newly acquired clinical strains since such strains have higher levels of AMR than those used to select them for genetic manipulation. Recently, the CRISPR-Cas (Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein) system has emerged as one of the most effective, efficient, and precise methods of genome editing and offers target-specific gene editing of AMR genes in a specific bacterial strain. CRISPR-based genome editing has been successfully applied in various bacterial strains to combat AMR; however, this strategy has not yet been extensively explored in A. baumannii. This review provides detailed insight into the progress, current scenario, and future potential of CRISPR-Cas usage for AMR-related gene manipulation in A. baumannii.

Formulating co-loaded nanoliposomes with gallic acid and quercetin for enhanced cancer therapy

Cancer is considered one of the top global causes of death. Natural products have been used in oncology medicine either in crude form or by utilizing isolated secondary metabolites. Biologically active phytomolecules such as gallic acid and quercetin have confirmed antioxidant, anti-bacterial, and neoplastic properties. There is an agreement that microorganisms could mediate oncogenesis or alter the immune system. This research project aims to develop a novel formulation of co-loaded gallic acid and quercetin into nanoliposomes and investigate the efficacy of the free and combined agents against multiple cancerous cell lines and bacterial strains. Thin-film hydration technique was adopted to synthesize the nanocarriers. Particle characteristics were measured using a Zetasizer. The morphology of nanoliposomes was examined by scanning electron microscopy, Encapsulation efficiency and drug loading were evaluated using High-Performance Liquid Chromatography. Cytotoxicity was determined against Breast Cancer Cells MCF-7, Human Carcinoma Cells HT-29, and A549 Lung Cancer Cells. The antibacterial activities were evaluated against Acinetobacter baumannii, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, and Staphylococcus aureus. Therapeutic formulas were categorized into groups: free gallic acid, free quercetin, free-mix, and their nano-counterparts. Findings revealed that drug loading capacity was 0.204 for the mix formula compared to 0.092 and 0.68 for free gallic acid and quercetin, respectively. Regarding the Zeta potential, the mix formula showed more amphiphilic charge than the free quercetin and free gallic acid formulas (P-values 0.003 and 0.002 receptively). On the contrary, no significant difference in polydispersity indices was reported. Lung cancerous cells were the most affected by the treatments. The best estimated IC50 values were observed in breast and lung cancer lines for the nano-gallic acid and co-loaded particles. The nano-quercetin formula exhibited the least cytotoxicity with an IC50 value of ≥200 μg/mL in both breast (MCF-7) and colorectal adenocarcinoma cell lines (HT-29) with no activity against the lung. A remarkable improvement in the efficacy of quercetin was measured after mixing it with gallic acid against the breast and lungs. The tested therapeutic agents exhibited antimicrobial activity against gram-positive bacteria. Nano-liposomes can either enhance or reduce the cytotoxicity activity of active compounds depending on the physical and chemical properties of drug-loaded and type of cancer cells.

Multidrug-Resistant Acinetobacter baumannii Infections in the United Kingdom versus Egypt: Trends and Potential Natural Products Solutions

Acinetobacter baumannii is a problematic pathogen of global concern. It causes multiple types of infection, especially among immunocompromised individuals in intensive care units. One of the most serious concerns related to this pathogen is its ability to become resistant to almost all the available antibiotics used in clinical practice. Moreover, it has a great tendency to spread this resistance at a very high rate, crossing borders and affecting healthcare settings across multiple economic levels. In this review, we trace back the reported incidences in the PubMed and the Web of Science databases of A. baumannii infections in both the United Kingdom and Egypt as two representative examples for countries of two different economic levels: high and low-middle income countries. Additionally, we compare the efforts made by researchers from both countries to find solutions to the lack of available treatments by looking into natural products reservoirs. A total of 113 studies reporting infection incidence were included, with most of them being conducted in Egypt, especially the recent ones. On the one hand, this pathogen was detected in the UK many years before it was reported in Egypt; on the other hand, the contribution of Egyptian researchers to identifying a solution using natural products is more notable than that of researchers in the UK. Tracing the prevalence of A. baumannii infections over the years showed that the infections are on the rise, especially in Egypt vs. the UK. Further concerns are linked to the spread of antibiotic resistance among the isolates collected from Egypt reaching very alarming levels. Studies conducted in the UK showed earlier inclusion of high-throughput technologies in the tracking and detection of A. baumannii and its resistance than those conducted in Egypt. Possible explanations for these variations are analyzed and discussed.

Genetic Configuration of Genomic Resistance Islands in Acinetobacter baumannii Clinical Isolates From Egypt

In Acinetobacter baumannii (A. baumannii), a wide repertoire of resistance genes is often carried within genomic resistance islands (RIs), particularly in high-risk global clones (GCs). As the first in Egypt, the current study aimed at exploring the diversity and genetic configuration of RIs in the clinical isolates of A. baumannii. For this purpose, draft genomes of 18 isolates were generated by Illumina sequencing. Disk diffusion susceptibility profiling revealed multidrug resistance (MDR) and extensive drug resistance (XDR) phenotypes in 27.7 and 72.2%, respectively. The highest susceptibility was noted for tigecycline (100.0%) followed by colistin (94.4%), for which an MIC₅₀ of 0.25 μg/ml was recorded by the broth microdilution assay. Sequence typing (ST) showed that the majority of the isolates belonged to high-risk global clones (GC1, GC2, and GC9). A novel Oxford sequence type (ST2329) that also formed a novel clonal complex was submitted to the PubMLST database. A novel bla_ADC variant (bla_ADC−258) was also identified in strain M18 (ST85^Pas/1089^Oxf). In addition to a wide array of resistance determinants, whole-genome sequencing (WGS) disclosed at least nine configurations of genomic RIs distributed over 16/18 isolates. GC2 isolates accumulated the largest number of RIs (three RIs/isolate) followed by those that belong to GC1 (two RIs/isolate). In addition to Tn6022 (44.4%), the comM gene was interrupted by AbaR4 (5.5%) and three variants of A. baumanniigenomic resistance island 1(AbGRI)-type RIs (44.4%), including AbaR4b (16.6%) and two novel configurations of AbGRI1-like RIs (22.2%). Three of which (AbaR4, AbaR4b, and AbGRI1-like-2) carried bla_OXA−23 within Tn2006. With less abundance (38.8%), IS26-bound RIs were detected exclusively in GC2 isolates. These included a short version of AbGRI2 (AbGRI2-15) carrying the genes bla_TEM−1 and aphA1 and two variants of AbGRI3 RIs carrying up to seven resistance genes [mphE-msrE-armA-sul1-aadA1-catB8-aacA4]. Confined to GC1 (22.2%), sulfonamide resistance was acquired by an ISAba1 bracketed GIsul2 RI. An additional RI (RI-PER-7) was also identified on a plasmid carried by strain M03. Among others, RI-PER-7 carried the resistance genes armA and bla_PER−7. Here, we provided a closer view of the diversity and genetic organization of RIs carried by a previously unexplored population of A. baumannii.

Whole genome sequence of pan drug-resistant clinical isolate of Acinetobacter baumannii ST1890

Acinetobacter baumannii is an opportunistic gram-negative bacteria typically attributed to hospital-associated infection. It could also become multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan drug-resistant (PDR) during a short period. Although A. baumannii has been documented extensively, complete knowledge on the antibiotic-resistant mechanisms and virulence factors responsible for pathogenesis has not been entirely elucidated. This study investigated the drug resistance pattern and characterized the genomic sequence by de novo assembly of PDR A. baumannii strain VJR422, which was isolated from a catheter-sputum specimen. The results showed that the VJR422 strain was resistant to any existing antibiotics. Based on de novo assembly, whole-genome sequences showed a total genome size of 3,924,675-bp. In silico and conventional MLST analysis of sequence type (ST) of this strain was new ST by Oxford MLST scheme and designated as ST1890. Moreover, we found 10,915 genes that could be classified into 45 categories by Gene Ontology (GO) analysis. There were 1,687 genes mapped to 34 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The statistics from Clusters of Orthologous Genes (COG) annotation identified 3,189 genes of the VJR422 strain. Regarding the existence of virulence factors, a total of 59 virulence factors were identified in the genome of the VJR422 strain by virulence factors of pathogenic bacteria databases (VFDB). The drug-resistant genes were investigated by searching in the Comprehensive Antibiotic Resistance Database (CARD). The strain harbored antibiotic-resistant genes responsible for aminoglycoside, β-lactam-ring-containing drugs, erythromycin, and streptogramin resistance. We also identified resistance-nodulation-cell division (RND) and the major facilitator superfamily (MFS) associated with the antibiotic efflux pump. Overall, this study focused on A. baumannii strain VJR422 at the genomic level data, i.e., GO, COG, and KEGG. The antibiotic-resistant genotype and phenotype as well as the presence of potential virulence associated factors were investigated.

Genetic Diversity of Antimicrobial Resistance and Key Virulence Features in Two Extensively Drug-Resistant Acinetobacter baumannii Isolates

In recent decades, Acinetobacter baumannii emerged as a major infective menace in healthcare settings due to scarce therapeutic options to treat infections. Therefore, undertaking genome comparison analyses of multi-resistant A. baumannii strains could aid the identification of key bacterial determinants to develop innovative anti-virulence approaches. Following genome sequencing, we performed a molecular characterization of key genes and genomic comparison of two A. baumannii strains, #36 and #150, with selected reference genomes. Despite a different antibiotic resistance gene content, the analyzed strains showed a very similar antibiogram profile. Interestingly, the lack of some important virulence determinants (i.e., bap, ata and omp33–36) did not abrogate their adhesive abilities to abiotic and biotic surfaces, as reported before; indeed, strains retained these capacities, although to a different extent, suggesting the presence of distinct vicarious genes. Conversely, secretion systems, lipopolysaccharide (LPS), capsule and iron acquisition systems were highly similar to A. baumannii reference strains. Overall, our analyses increased our knowledge on A. baumannii genomic content and organization as well as the genomic events occurring in nosocomial isolates to better fit into changing healthcare environments.