Selective Covalent Basal Plane Modification as a Probe of Hydroxide Ion Conduction Pathways in Magnesium Aluminum Layered Double Hydroxides.

Understanding ionic conduction in layered double hydroxides (LDHs) is a crucial step towards utilizing them as solid, hydroxide ion-conducting electrolytes in energy conversion applications. We selectively modified the interlayer and external surfaces of MgAl LDHs with tris(hydroxymethyl)aminomethane (TRIS) ligands. By adjusting the concentration of the TRIS surface modifier, the LDH basal plane surfaces could be functionalized everywhere (internally and externally) or only externally. External modification resulted in loss of OH-conductivity compared to pristine LDHs, confirming that external platelet surfaces are the primary ion conduction pathway.

Clinical and Therapeutic Characteristics of Hospitalized Patients with Advanced Lung Cancer in Najran, Saudi Arabia: A Retrospective Study.

BACKGROUND: Lung cancer is one of the top causes of cancer deaths globally, including in Saudi Arabia. Although several prognostic markers have been established, the clinical features and outcomes of lung cancer in Saudi Arabia are not well understood. This study aimed to describe the clinical and therapeutic characteristics of advanced lung cancer in Najran, Saudi Arabia. METHOD: A retrospective chart review of 44 patients diagnosed with advanced lung cancer between June 2018 and September 2021 and treated at the Oncology Center of King Khalid Hospital in Najran City, Saudi Arabia. The clinicopathological features, treatment used, response, and survival outcomes were collected and analyzed. RESULT: The mean age was 69.3 ± 10.7 years, most of them (n = 35, 79.5%) were male and older than 70 years (n = 24, 54.5%). Adenocarcinoma was the most observed cancer (n = 35, 79.5%), followed by squamous cell carcinoma in six (13.6%). Most cases (n = 42, 95.5%) were in stage IV. Epidermal growth factor receptor (EGFR) mutations were positive in two (4.5%) cases and ALK mutation was positive in two (4.5%) cases. Metastasis to pleura with pleural effusion was the common presentation (n = 41, 93%). Chemotherapy was administered as the first line in 19 cases (43.2%) while 25 cases (56.8%) received chemoimmunotherapy. The commonest chemoimmunotherapy regimen used was carboplatin-pemetrexed-pembrolizumab in 16 (36.4%), followed by carboplatin-paclitaxel-pembrolizumab in 9 (20.5%) cases. The response to initial systemic therapy was as follows disease progression, stable disease, and complete remission in 10 (22.7%), 33 (75.0%), and 1 (2.3%), respectively. Median progression-free survival was 8.7 months (interquartile range (IQR): 5.7-11.4), and the median overall survival was 12.3 months (IQR: 11.1-13.4). Among the total documented 36 (81.8%) dead cases, disease progression was the main cause of death in 25 cases (56.8%). Using chemoimmunotherapy as the first-line therapy was associated with numerical survival improvement compared to using chemotherapy alone (HR: 0.75; 95% CI: 0.39-1.46) however, it was not statistically significant (p = 0.397). CONCLUSION: In this study, the majority of lung cancer patients were male and over 70 years old. Adenocarcinoma was the most common histological type. Metastasis to pleura with pleural effusion was the common presentation. The most common treatment used was chemoimmunotherapy with a regimen of carboplatin-pemetrexed-pembrolizumab. Addressing the possible causes of delayed diagnosis of lung cancer is crucial for improved survival outcomes.

Highly Sensitive Diethylamine Detection at Room Temperature Using g-C3N4 Nanosheets Decorated with CuO Hollow Polyhedral Structures.

Chemiresistive-based metal oxide semiconductor (MOS) gas sensors are widely used in gas sensing due to their advantageous properties. Graphitic carbon nitride (g-C3N4) and metal oxide heterostructure materials can improve charge transport properties, selectivity, and sensitivity in MOS gas sensor materials. Herein, for the first time, CuO hollow polyhedral structures (HPSs) were synthesized via a hydrothermal technique and annealed at different temperatures, with the 400 °C annealed (CuO-400 HPSs) demonstrating remarkable sensing capabilities for diethylamine (DEA) gas at room temperature (RT). The x-g-C3N4 nanosheets were decorated with CuO HPSs in varying amounts (x = 0.8, 1.8, 2.1, and 3.1 wt %) and then annealed at 400 °C for x-g-C3N4-CuO-400 hollow polyhedral heterostructures (HPHSs). Indeed, among the synthesized samples, the 1.8%-g-C3N4-CuO-400 HPHSs have a higher sensitivity to DEA (resistance change in gas (Rg) and air (Ra); Rg/Ra= 65 @ 20 ppm), a low detection limit (Rg/Ra= 6 @ 500 ppb), wide dynamic response (Rg/Ra= 190 @ 80 ppm), strong stability (30 days), and 21.6 times higher sensitivity than pure CuO at RT toward 20 ppm of DEA. The exceptional gas-sensing behavior can be attributed to various factors, including controlled annealing conditions that result in the formation of well-defined structures and greater porosity, efficient charge transfer properties resulting from an optimized ratio of g-C3N4 to CuO in HPHSs, an abundance of defects, unsaturated Cu sites, and synergistic effects. The study presents a universal strategy for generating sensitive and selective g-C3N4-based composite materials for low-temperature gas sensors.

Burden and outcome of respiratory morbidities among children and adolescents with sickle cell disease-A retrospective review of emergency presentations in some Nigerian tertiary institutions.

BACKGROUND: Despite the huge burden of sickle cell disease (SCD) among Nigerian children, the burden and outcome of respiratory illnesses remain undocumented. Thus, we aimed to describe the spectrum and outcome of respiratory illnesses among SCD childrenand adolescentadmissions in ten Nigerian tertiary hospitals. METHOD: A retrospective review of the SCD admission records of children and adolescents with a confirmed diagnosis of respiratory illnesses from 2012 to 2021 in ten tertiary health facilities across five geopolitical zones in Nigeria was conducted. The data, collectedbetween March and June 2023, included the age, sex, diagnosis, complications, duration and outcome of hospitalization. RESULTS: Of the 72,333 paediatric admissions, 7,256 (10.0%) had SCD; the proportion of SCD from the total admission ranged from 2.1 to 16.3% in the facilities. Of the 7,256 children and adolescents with SCD, 1,213 (16.7%) had respiratory morbidities. Lower respiratory disease was the most common (70.0%) respiratory entity and the majority were pneumonia (40.1.0%), followed by acute chest syndrome (26.7%). Seventeen (1.4%) patients died; all had lower respiratory diseases [(acute chest syndrome ACS (11, 64.7%), pneumonia; 5, 29.4%, and asthma (1, 5.9%). Based on the proportion of deaths among overall SCD, the 17 death cases contributed 9.4% (95% CI 5.9 to 14.5). Factors associated with deaths included duration of hospitalization less than 72 hours and lower respiratory tract diseases. CONCLUSION: Sickle cell disease is a major contributor to hospitalization among Nigerian children and adolescents, with high respiratory morbidity and mortality. Pneumonia and acute chest syndrome were associated with mortality, andthe highest risk of death within the first 72 hours.

Evaluation of Immulex S. pneumoniae Omni test for the direct detection of S. pneumoniae from positive blood cultures.

Rapid and early identification of Streptococcus pneumoniae from positive blood cultures is crucial for the management of patients with bloodstream infections (BSI). Many identification systems in microbiology laboratories have difficulty differentiating S. pneumoniae from other closely related species in the Streptococcus mitis group. To overcome this limitation, we developed a rapid workflow in our laboratory combining direct MALDI-TOF MS identification with the Immulex S. pneumoniae Omni test (SSI Diagnostica, Denmark) for rapid detection of S. pneumoniae directly from positive blood cultures. The workflow was evaluated using 51 Streptococcus isolates. Compared to conventional biochemical testing, our new workflow demonstrates 100 % specificity and sensitivity for the detection and differentiation of S. pneumoniae from other closely related species. Our new workflow is accurate, cost-effective, and can easily be implemented in microbiology laboratories that already perform direct MALDI-TOF identification from positive blood cultures to improve the management of patients with invasive pneumococcal disease. Importance: Invasive pneumococcal disease remains a major public health problem worldwide. Reducing the time to identify Streptococcus pneumoniae in positive blood cultures allows patients to be treated sooner with more targeted and effective antibiotics. We evaluated a two-step protocol where positive blood cultures are first tested directly by MALDI-TOF MS and any samples containing Streptococcus species are tested by Immulex S. pneumoniae Omni test to both detect and differentiate S. pneumoniae from other closely related Streptococcus species. Our study results showed 100 % sensitivity and specificity, and a much faster turn-around time than conventional methods.

Effect of daflon-500®, a flavonoid compound on chlorpyriphos-induced oxidative changes in the hypophysis and testes in adult male rats.

Alteration of redox status is one of the molecular pathways commonly associated with pesticide toxicity. Antioxidants, including those obtained from plant phenolics, have been shown to mitigate pesticide-induced cellular injury. The present study was aimed at evaluating the effect of daflon-500 ® , a flavonoid compound on sub-chronic chlorpyriphos-evoked changes in antioxidant and biochemical parameters in the hypophysis and testes of adult male rats. Twenty-five male albino rats were randomly divided into 5 groups of 5 animals each. Group I (DW) received distilled water (2 ml/kg); group II (SO) was dosed with soya oil (2 ml/kg); Group III (DAF) received daflon-500 ® at 1000 mg/kg ~ 1/5th of LD50 (≥ 5000 mg/kg); group IV (CP) was administered chlorpyriphos at 7.74 mg/kg ~ 1/10th of LD50 (77.4 mg/kg) while group V (DAF + CP) was previously treated with daflon-500 ® (1000 mg/kg) and then exposed to CP (7.74 mg/kg), 30 min later. Daily oral regimen administration was done for 60 days after which the animals were sacrificed by cervical venesection after light chloroform anesthesia. The hypophysis and testicular tissues were harvested, and their homogenates were analyzed for malondialdehyde, catalase and superoxide dismutase, and acetylcholinesterase levels. A significant increase in the hypophysis and testicular MDA concentrations, coupled with a decrease in the SOD, CAT, and AChE activities were observed in the CP group. The levels of these oxidative and biochemical parameters were alleviated in the group pretreated with Daflon-500 ® . Results of this study demonstrated that pre-treatment with Daflon-500 ® mitigated CP-induced alterations in oxidative and biochemical parameters apparently due to the antioxidant effect of the flavonoid compound.

In vitro anthelmintic activity of Dennettia tripetala G. Baker (Annonaceae) Fruits against Haemonchus contortus.

Helminthosis is one of the greatest causes of parasitic disease and loss in animal productivity. As such, the control of helminth parasites is of critical importance. This study was aimed to investigate the in vitro anthelmintic activity of Dennettia tripetala G. Baker (Annonaceae) fruits against Haemonchus contortus. Using in vitro techniques, the anthelmintic activity of extracts and fractions of D. tripetala G. Baker (Annonaceae) was evaluated for ovicidal (Egg hatch inhibition test) and larvicidal (larval mortality test) activity. Besides, the maximum tolerated dose was determined in adult albino rats administered, 300, 400, and 500 mg/kg body weight of the CME fraction, and observed over a period of 48 h for signs of toxicity and mortality. Phytochemical screening uncovered the occurrence of flavonoids, steroids/triterpenes, cardiac glycosides, saponins, tannins, carbohydrates, and alkaloids in the crude methanol extract (CME), the ethyl acetate fraction (EAF), and butanol fraction. The maximum tolerated dose of the CME of D. tripetala did not produce observable signs of toxicity or death in all the rats given up to 500 mg/kg. The CME and EAF of D. tripetala fruits produced a significant ( p < 0.05 ) reduction in the hatchability of H. contortus eggs in a concentration-dependent manner, while the CME at concentrations between 12.5 and 100 mg/ml completely inhibited the hatching of H. contortus eggs. Similarly, EAF at doses of 25, 50, and 100 mg/ml completely inhibited the hatching of H. contortus eggs. The CME and EAF of D. tripetala fruits produced significant ( p < 0.05 ) larvicidal activity against L3 of H. contortus in a concentration-dependent manner while the CME at concentrations between 6.25 and 100 mg/ml caused larval mortality of H. contortus L3 larvae completely. This study suggests that methanol extract and fractions of D. tripetala fruits possess beneficial anthelmintic (ovicidal and larvicidal) activity against H. contortus, and may be a suitable alternative anthelmintic candidate for the control of nematodes.

In vitro and in vivo anthelmintic effects of Sterospermum kunthianum (Cham-Holl) leaf extract against Ascaridia galli in experimentally infected broiler chickens.

This study was to assess the anthelminthic potential of Sterospermum kunthianum leaf extract against Ascaridia galli in experimentally infected broiler chickens. The extract and fractions were evaluated for in vitro inhibition and in vivo anthelmintic effects. Acute toxicity studies of extract revealed no sign of toxicity or death in birds at oral dose range of 1000-5000 and was considered safe. There was a concentration dependent decrease on inhibition of A. galli egg embryonation and deparasitization. At 100 mg/ml, albendazole (ALB) caused the highest inhibition of embryonation (195.3 ± 0.9) which was not significantly different from the decrease caused by crude methanol extract (CME) (188 ± 0.9), hexane fraction (HF) (177 ± 1.2) or ethyl acetate fraction (EAF) (168.3 ± 0.9). The highest inhibition rates (%) were 97, 94, 88 and 85 for ALB, CME, HF and EAF, respectively. The deparasitization obtained at day 21 in ALB (95.62%) treated birds was not significantly (P > 0.05) different from the 81.27% and 89.24% obtained from the crude methanol treated birds. The deparasitization caused by CME at 400 mg/kg (89.24%) was significantly higher than the one caused by EAF at the same dose (50.19%). Day 21 post treatment, significantly (P < 0.05) higher deparasitization was recorded for CME and HF at dosage of 400 mg/kg when compared to 200 mg/kg. Histopathology findings revealed necrosis of the mucosal gland and villi in chickens. In conclusion, the leaf extract and fractions S. kunthianum have been shown to possess anthelmintic activity.

Antitrypanosomal properties of Anogeissus leiocarpa extracts and their inhibitory effect on trypanosome alternative oxidase.

Background: African trypanosomiasis is a protozoan disease with huge socio-economic burden to sub-Saharan African exceeding US$4.6 annual loss. To mitigate the incidence of trypanosomal drug resistance, efforts are geared towards discovery of molecules, especially from natural products, with potential to inhibit important molecular target (trypanosome alternative oxidase, TAO) in trypanosomes that are critical to their survival. Method: Crude methanol extract of Anogeissus leiocarpa was subjected to in vitro bioassay-guided antitrypanosomal assay to identify the most active extract with trypanocidal activity. The most active extract was run on a column chromatography yielding five fractions, F1-F5. The fractions were assayed for inhibitory effect on TAO. The most promising TAO inhibitor was subjected to antitrypanosomal evaluation by trypanosome count, drug incubation infectivity test (DIIT) and in vivo studies. Gas chromatography-mass spectrometry (GC-MS) was used to identify and quantify phytochemical constituents of the potential TAO-inhibiting fraction. Results: Ethyl acetate extract (EtOAc) significantly (p<0.05) produced trypanocidal effect and was the most active extract. Of the five fractions, only F4 significantly (p<0.05) inhibited TAO compared to the control. F4 completely immobilised the trypanosomes up to 0.5 µg/µl, yielding an EC50 of 0.024 µg/µl compared to the 0.502 µg/µl of diminazene aceturate positive control group. The DIIT showed that F4 was significantly (p<0.05) potent up to 0.1 µg/µl. F4 significantly (p<0.05) suppressed parasite multiplication in systemic circulation of the treated rats and significantly (p<0.05) maintained high PCV when compared to the 5% DMSO group. Furthermore, F4 significantly (p<0.05) lowered serum concentrations of malondialdehyde. Phytoconstituents identified by the GC-MS include tetradecene; cetene; 3-(benzylthio) acrylic acid, methyl ester; 1-octadecene; 9-heptadecanone; hexadecanoic acid, methyl ester; dibutyl phthalate; eicosene; octadecenoic acid, methyl ester; oleic acid; 2-methyl-Z,Z-3,13-octadecadienol; 1-docosene; 3-phenylthiane, s-oxide; phenol, 3-methyl; phthalic acid, di(2-propylpentyl) ester and 1,4-benzenedicarboxylic acid, bis (2-ethylhexyl) ester. Conclusion: F4 from EtOAc contains six carbohydrates (9.58%), two free fatty acids (6.48%), five fatty acid esters (27.73%), two aromatic compounds (50.63%) and one organosulphide (5.61%). It inhibited TAO and demonstrated antitrypanosomal effects.

Partially Purified Leaf Fractions of Azadirachta indica Inhibit Trypanosome Alternative Oxidase and Exert Antitrypanosomal Effects on Trypanosoma congolense.

INTRODUCTION: Trypanosomiasis is a neglected disease of humans and livestock caused by single-celled flagellated haemo-protozoan parasites belonging to the genus Trypanosoma. PURPOSE: Widespread resistance to trypanocidal drugs creates urgent need for new, more effective drugs with potential to inhibit important trypanosome molecular targets. METHODS: Nine column chromatographic, partially purified leaf fractions of Azadirachta indica (AIF) were subjected to trypanosome alternative oxidase (TAO) inhibition assay using ubiquinol oxidase assay. The potent TAO inhibitors were evaluated for trypanocidal activities against T. congolense in rat model using in vitro, ex vivo, and in vivo assays. Complete cessation or reduction in parasite motility was scored from 0 (no parasite) to 6 (greater than or equal to 6 × 107 trypanosomes/milliliter of blood), and was used to evaluate the efficacy of in vitro treatments. RESULTS: Only AIF1, AIF2, and AIF5 significantly inhibited TAO. AIF1 and AIF5 produced significant, dose-dependent suppression of parasite motility reaching score zero within 1 h with EC50 of 0.005 and 0.004 µg/µL, respectively, while trypanosome-laden blood was still at score six with an EC50 of 44,086 µg/µL. Mice inoculated with the concentrations at scores 0 and 1 (1-2 moribund parasites) at the end of the experiment did not develop parasitaemia. The two fractions significantly (p < 0.05) lowered parasite burden, with the AIF5 exhibiting highest in vivo trypanocidal effects. Packed cell volume was significantly higher in AIF1 (p < 0.05) and AIF5 (p < 0.001) groups compared to DMSO-treated group. Only AIF5 significantly (p < 0.05) lowered malondialdehyde. CONCLUSION: AIF1 and AIF5 offer prospects for the discovery of TAO inhibitor(s).

Evaluation of Rapid Immunochromatographic Tests for the Direct Detection of Extended Spectrum Beta-Lactamases and Carbapenemases in Enterobacterales Isolated from Positive Blood Cultures.

NG-Test CTX-M MULTI and NG-Test Carba 5 (NG Biotech) are two rapid in vitro immunochromatographic assays that are widely used for the detection of the most common extended spectrum beta-lactamases (ESBL) and carbapenemases in Enterobacterales. ESBL and carbapenemases are leading causes of morbidity and mortality worldwide and their rapid detection from positive blood cultures is crucial for early initiation of effective antimicrobial therapy in bloodstream infections (BSI) involving antibiotic-resistant organisms. In this study, we developed a rapid workflow for positive blood cultures for direct identification of Enterobacterales by MALDI-TOF mass-spectrometry, followed by detection of ESBL and carbapenemases using NG-Test CTX-M MULTI and NG-Test Carba 5 (NG Biotech). The workflow was evaluated using Enterobacterales isolates (n = 114), primarily Klebsiella species (n = 50) and Escherichia coli (n = 40). Compared to the standard testing approach in our institution using BD Phoenix, our new testing approach demonstrates 100% sensitivity and specificity for organism identification and detection of ESBL and carbapenemases. Implementation of a rapid workflow in diagnostic microbiology laboratories will enable more effective antimicrobial management of patients with BSI due to ESBL- and carbapenemase-producing Enterobacterales. IMPORTANCE The incidence of bloodstream infections (BSI) with extended spectrum beta-lactamase (ESBL) producing and carbapenemase producing Enterobacterales (CPE) is increasing at an alarming rate, for which only limited therapeutic options remain available. Rapid identification of these bacteria along with their antibiotic resistance mechanisms in positive blood cultures with Gram-negative bacteria will allow for early initiation of effective therapy and limit the overuse of broad-spectrum antibiotics in BSI (1). In this study we evaluated a combined approach of testing positive blood cultures directly, using MALDI-TOF MS followed by rapid immunochromatographic tests, for the detection of ESBLs and CPEs. Our approach demonstrates 100% sensitivity and specificity for the identification of Enterobacterales and detection of ESBLs and CPEs in positive blood culture with a turnaround time (TAT) of ≤60 min compared to a TAT of 48 h required by conventional culture and susceptibility testing methods.

Anthelmintic activity of methanol extract of Dennettia tripetala G. Baker (Annonaceae) fruits against Haemonchus contortus in red Sokoto goats.

Haemonchosis is a gastrointestinal parasitic disease of economic importance in ruminants especially sheep and goats. In view of the rising costs of conventional veterinary anthelmintics and the development of resistance by Haemonchus contortus, there is a need to develop alternative ethnoveterinary therapies for the treatment and management of Haemonchosis. This study investigated the anthelmintic activity of Dennettia tripetala G. Baker (Annonaceae) fruits against Haemonchus contortus in red Sokoto goats. The maximum tolerated dose was determined in adult albino rats administered, 3000, 4000, and 5000 mg/kg body weight of the crude methanol extract (CME) fraction, and observed over a period of 48 h for signs of toxicity and mortality. The in vivo anthelmintic activity was evaluated using 20 kids infected with H. contortus and randomly allocated into 5 groups (1, 2, 3, 4, and 5). Kids in groups 1, 2, and 3 were treated with CME at doses of 1250, 2500, and 5000 mg/kg respectively for 3 consecutive days per os. Groups 4 and 5 were treated with albendazole (7.5 mg/kg) once and distilled water (5 ml) respectively and served as treated and untreated controls. Blood samples were collected for haematology. The maximum tolerated dose of the CME of D. tripetala did not produce observable signs of toxicity or death in all the rats given up to 5000 mg/kg. There was significant (P < 0.05) reduction in faecal egg count by CME at doses of 1250 mg/kg (91.6%), 2500 mg/kg (98.5%), and 5000 mg/kg (100%) at day 14 post-treatment. The total plasma protein (TPP) and FAMACHA© scoring values were significantly improved (P < 0.05) in the treated groups. These results indicate that methanol extract and fractions of D. tripetala fruits possess beneficial anthelmintic activity against H. contortus and may be a suitable alternative anthelmintic candidate for the control of haemonchosis in goats.

Performance and Impact on Initial Antibiotic Choice of Direct Identification of Pathogens from Pediatric Blood Culture Bottles Using an In-House MALDI-TOF MS Protocol.

The performance and early therapeutic impact of direct identification by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF; DIMT) on pediatric blood culture bottles using in-house-developed methods to obtain microbial pellets for spectrometric analysis have seldom been studied. During a 2-year period (June 2018 to May 2020), DIMT was performed on broths from positive pediatric blood culture bottles using an in-house-developed method. Organism identifications with a score of ≥1.6 were notified to treating clinicians. Therapeutic modifications that occurred after the communication of DIMT were reviewed through the electronic medical records. DIMT was performed on 530 pediatric positive blood culture bottles. Among 505 monomicrobial bottles, identifications from 298 (97.7%) deemed as bloodstream infections (BSI) and 189 (94.5%) as contaminations had DIMT notified to clinicians. All identifications were correct except for one Streptococcus mitis incorrectly reported as Streptococcus pneumoniae. Therapy modifications resulting from DIMT occurred in 27 (8.3%) patients with BSI. Deescalation from effective or ineffective broad-spectrum regimens occurred mainly in Enterococcus faecalis bacteremia, whereas appropriate escalation from an ineffective regimen with narrower spectrum occurred mainly in bacteremia caused by AmpC-ß-lactamase-producing Enterobacterales. Escalation therapy was instituted significantly faster than deescalation therapy (median time, 0.75 versus 10.5 h [P = 0.01]). DIMT also enabled clinicians to confirm contamination in nearly one-half of patients with contaminated blood cultures. Our DIMT method applied to positive pediatric blood culture bottles demonstrated reliable performance for the rapid identification of pathogens. Our DIMT approach allowed therapeutic optimization in BSI, especially involving microorganisms with intrinsic antibiotic resistance, and was helpful in the early identification of likely contaminants. IMPORTANCE We demonstrate the performance and early impact on the antimicrobial management of bloodstream infections of an inexpensive, in-house preparation method for direct identification of bloodstream pathogens in pediatric blood culture bottles by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry.

Fecal Carriage and Molecular Characterization of Carbapenemase-Producing Enterobacterales in the Pediatric Population in Qatar.

Whole-genome sequencing was used to characterize carbapenemase-producing Enterobacterales (CPE) strains recovered from rectal screening swab samples obtained from children at a tertiary-care pediatric hospital in Qatar during a 3-year period. A total of 72 CPE isolates recovered from 61 fecal carriers were characterized. Escherichia coli (47 isolates [65.3%]) and Klebsiella pneumoniae (22 isolates [30.6%]) were the most common species identified. High levels of genetic diversity were observed for both species. These 72 isolates produced 78 carbapenemases, characterized as either NDM-type (41 enzymes [52.6%]) or OXA-48-type (37 enzymes [47.4%]). NDM-5 (24 enzymes [30.8%]), NDM-1 (15 enzymes [19.2%]), and OXA-181 (15 enzymes [19.2%]) were the most common variants detected within each type. Twenty-three NDM producers exhibited difficult-to-treat resistance, compared with only 2 of the OXA-48 producers. Multiple comorbidities were identified in 88.5% of the patients, whereas recent travel history to countries in which CPE are endemic was documented for 57.4% of the patients. All 9 blaOXA-48-type-gene-containing E. coli sequence type 38 (ST38) strains were isolated from patients without international travel history. The mean quarterly incidence of fecal carriage decreased more than 6-fold after the implementation of coronavirus disease 2019 (COVID-19)-related international travel restrictions in Qatar in mid-March 2020. Our data suggest that NDM-type and OXA-48-type carbapenemases expressed by a large diversity of E. coli and K. pneumoniae genotypes are largely dominant in the pediatric population of Qatar. Although our data indicate successful local expansion of E. coli ST38 strains harboring blaOXA-244 genes, at least within health care settings, blaOXA-48-type and blaNDM-type genes appear to have been mainly introduced sporadically by asymptomatic carriers who visited or received health care in some nearby countries in which the genes are endemic. IMPORTANCE To the best of our knowledge, this is the first study addressing the molecular characteristics of CPE in a pediatric population in Qatar using whole-genome sequencing. Since several countries in the Arabian Peninsula share relatively similar demographic patterns and international links, it is plausible that the molecular characteristics of CPE in children, at least in the middle and eastern parts of the region, are similar to those observed in our study.