Successful Treatment of Postneurosurgical Ventriculitis Caused by Extensively Drug-resistant Acinetobacter baumannii in a Child: Case Report

Introduction: The incidence of postneurosurgical Acinetobacter baumannii ventriculitis/meningitis, primarily due to drug-resistant strains, has increased considerably in recent years. However, limited therapeutic options are available because most antibiotics poorly penetrate the blood-brain barrier, especially in pediatric patients. Case Presentation: A five-year-old boy developed ventriculitis due to extensively drug-resistant A. baumannii (XDRAB) after bilateral frontal external ventricular drainage for spontaneous intraventricular hemorrhage. The boy was safely and successfully treated with intraventricular (IVT)/intrathecal (ITH) polymyxin B together with intravenous tigecycline plus cefoperazone/sulbactam. Conclusions: In the present case, postneurosurgical XDRAB ventriculitis was closely associated with intraventricular hemorrhage and the placement of external ventricular drainage. IVT/ITH polymyxin B combined with intravenous tigecycline and cefoperazone sulbactam could be a therapeutic option against XDRAB ventriculitis in children.

Impact of host factors on susceptibility to antifungal agents

An obstacle to drug development, particularly in this era of multiple drug resistance, is the under-appreciation for the role the host environment plays in microbial response to drugs. With the rise in fungal infection and drug resistance, particularly in individuals with co-morbidities, the influence serum and its components have on antimicrobial susceptibility requires assessment. This study examined the impact of physiologically relevant glucose and insulin levels in the presence and absence of 50 % human plasma on MICs for clinical isolates of Candida lusitaniae, Candida parapsilosis, Candida albicans, Candida tropicalis, Candida glabrata, Candida krusei and Cryptococcus neoformans. The addition of insulin or glucose at physiologic levels in RPMI medium alone altered the MIC in either a positive or negative fashion, depending on the organisms and drug tested, with C. glabrata most significantly altered with a 40, >32- and 46-fold increase in MIC for amphotericin B, itraconazole and miconazole, respectively. The addition of candida-antibody negative plasma also affected MIC, with the addition of glucose and insulin having a tandem effect on MIC. These findings indicate that phenotypic resistance of Candida and Cryptococcus can vary depending on the presence of insulin with glucose and plasma. This modulation of resistance may help explain treatment failures in the diabetic population and facilitate the development of stable drug-resistant strains. Furthermore, these findings indicate the need for a precision approach in the choice of drug treatment and drug development.

Molecular Network Analysis Reveals Transmission of HIV-1 Drug-Resistant Strains Among Newly Diagnosed HIV-1 Infections in a Moderately HIV Endemic City in China

Since the implementation of the “treat all” policy in China in 2016, there have been few data on the prevalence of transmitted drug resistance (TDR) in China. In this study, we describe TDR in patients newly diagnosed with human immunodeficiency virus (HIV) infection between 2016 and 2019 in Shenyang city, China. Demographic information and plasma samples from all newly reported HIV-infected individuals in Shenyang from 2016 to 2019 were collected. The HIV pol gene was amplified and sequenced for subtyping and TDR. The spread of TDR was analyzed by inferring an HIV molecular network based on pairwise genetic distance. In total, 2,882 sequences including CRF01_AE (2019/2,882, 70.0%), CRF07_BC (526/2,882, 18.3%), subtype B (132/2,882, 4.6%), and other subtypes (205/2,882, 7.1%) were obtained. The overall prevalence of TDR was 9.1% [95% confidence interval (CI): 8.1–10.2%]; the prevalence of TDR in each subtype in descending order was CRF07_BC [14.6% (95% CI: 11.7–18.0%)], subtype B [9.1% (95% CI: 4.8–15.3%)], CRF01_AE [7.9% (95% CI: 6.7–9.1%)], and other sequences [7.3% (95% CI: 4.2–11.8%)]. TDR mutations detected in more than 10 cases were Q58E (n = 51), M46ILV (n = 46), K103N (n = 26), E138AGKQ (n = 25), K103R/V179D (n = 20), and A98G (n = 12). Molecular network analysis revealed three CRF07_BC clusters with TDR [two with Q58E (29/29) and one with K103N (10/19)]; and five CRF01_AE clusters with TDR [two with M46L (6/6), one with A98G (4/4), one with E138A (3/3), and one with K103R/V179D (3/3)]. In the TDR clusters, 96.4% (53/55) of individuals were men who have sex with men (MSM). These results indicate that TDR is moderately prevalent in Shenyang (5–15%) and that TDR strains are mainly transmitted among MSM, providing precise targets for interventions in China.

Antibacterial Activity of Pharmaceutical-Grade Rose Bengal: An Application of a Synthetic Dye in Antibacterial Therapies

Rose bengal has been used in the diagnosis of ophthalmic disorders and liver function, and has been studied for the treatment of solid tumor cancers. To date, the antibacterial activity of rose bengal has been sporadically reported; however, these data have been generated with a commercial grade of rose bengal, which contains major uncontrolled impurities generated by the manufacturing process (80–95% dye content). A high-purity form of rose bengal formulation (HP-RBf, >99.5% dye content) kills a battery of Gram-positive bacteria, including drug-resistant strains at low concentrations (0.01–3.13 μg/mL) under fluorescent, LED, and natural light in a few minutes. Significantly, HP-RBf effectively eradicates Gram-positive bacterial biofilms. The frequency that Gram-positive bacteria spontaneously developed resistance to HP-RB is extremely low (less than 1 × 10−13). Toxicity data obtained through our research programs indicate that HP-RB is feasible as an anti-infective drug for the treatment of skin and soft tissue infections (SSTIs) involving multidrug-resistant (MDR) microbial invasion of the skin, and for eradicating biofilms. This article summarizes the antibacterial activity of pharmaceutical-grade rose bengal, HP-RB, against Gram-positive bacteria, its cytotoxicity against skin cells under illumination conditions, and mechanistic insights into rose bengal’s bactericidal activity under dark conditions.

Artemisinin-acetylenedicarboxylic acid cocrystal: screening, structure determination, and physicochemical property characterisation

Artemisinin is used to treat malaria, even when caused by multi-drug resistant strains of the Plasmodium parasite; the compound also shows good promise as an anti-cancer drug. However, the usage...

Screening and Characterization of Soil Microbes Producing Antimicrobial Compounds in Makkah Province, Saudi Arabia

This study aimed to investigate a method to manage antimicrobial resistance (AMR) issues by exploring soil microorganisms that are capable of producing bioactive compounds. Eight different types of soil were selected from three locations to screen, isolate, and identify microorganisms that are capable of producing antimicrobial compounds. The multi-drug resistant strains are Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans were selected for primary and secondary screening using the crowded plate method and the agar well diffusion method. Inhibition zones were measured, and data were assessed using statistical tests to check for normality and differences between parametric variables and nonparametric data. This was followed by biochemical characterization, DNA isolation, and polymerase chain reaction (PCR). Molecular identification was performed using 16S rRNA amplification and sequencing. Here, 86 isolates containing bacteria and fungi were successfully extracted from soil samples. Further, 49 of 86 microbes showed possible antimicrobial activity, but only 12 isolates resulted in distinct inhibition zones with the selected multi-drug resistant strains. The following different taxa were identified: Firmicutes (nine strains), Proteobacteria (one strain), Actinobacteria (one strain), and Azotobacter (one strain). Species are represented in a phylogenetic tree, which was constructed using the unweighted pair-group method with arithmetic mean (UPGMA) method. The evolutionary distances were computed using the Maximum Composite Likelihood method. The identified microorganisms showed antimicrobial activity, confirming that soil microorganisms have great potential to address AMR issues.

Microbial Load and Antibiotic Resistance of Escherichia coli and Staphylococcus aureus Isolated from Ready-to-Eat (RTE) Khebab Sold on a University Campus and Its Environs in Ghana

The demand for ready-to-eat (RTE) foods is handy to busy urban dwellers. Handling, processing, and selling are known to contaminate these foods and cause foodborne outbreaks. This study assessed a load of S. aureus and E. coli in khebabs (beef, chevon, and gizzard) sold on the KNUST campus and its environs and how resistant they are to clinically relevant antimicrobial agents. Thirty-six (36) khebab samples were purchased from vendors at Kotei, Ayeduase, Kentinkrono, Boadi, KNUST campus, and Ayigya. They were analyzed for S. aureus and E. coli and their resistance to clinically relevant antimicrobial agents checked using standard methods. S. aureus and E. coli load ranged from 4.09 to 5.96 CFU/g and 1.79 to 6.12 MPN/g in beef, 4.02 to 6.01 CFU/g and 1.99 to 4.44 MPN/g in chevon, and 5.37 to 6.18 CFU/g and 1.79 to 6.10 MPN/g in gizzard khebabs in the different locations. E. coli (n = 27) were multiresistant to ampicillin, tetracycline, gentamicin, cefuroxime, ceftriaxone, cefotaxime, and cotrimoxazole (51.85%) and susceptible to chloramphenicol (100%). S. aureus (n = 36) isolates were multiresistant to penicillin, tetracycline, flucloxacillin, cefuroxime, ampicillin (97.22%), erythromycin (75%), cotrimoxazole (86.11%), and gentamicin (69.44%). It can therefore be concluded that the majority of khebabs from the KNUST campus and its environs were contaminated with S. aureus and E. coli above the acceptable standard limits (≤4 log10 CFU/g and ˂2 log10MPN/g, respectively). Also, the S. aureus and E. coli isolated were multiresistant to the antibiotics tested and could be a medium for the transmission of antibiotic-resistant bacteria and therefore expose consumers to a high risk of contracting foodborne infections with drug-resistant strains.

Molecular Detection of epsA-Mediated and Extracellular Polysaccharide-Mediated Biofilm Formation Among Multidrug Resistant Strains of Acinetobacter baumannii

The epsA associated biofilm formation attributes to potent virulence in the drug resistant strains of Acinetobacter baumannii. This study is aimed to molecularly characterize the epsA gene among the multidrug resistant clinical isolates of A. baumannii and to assess the frequency of the same in different drug resistant groups. To detect the biofilm formation among the selected MDR strains of A. baumannii, semi-quantitative adherent bioassay was performed using crystal violet staining method. Further PCR amplification was done to screen the presence of epsA gene with further sequencing of the amplicons. Pearson’s correlation analysis was done to check the correlation of the occurrence of epsA gene with drug resistant strains (p-value<0.05). 58.9%, 31.5% and 0.9% of the strains were recorded as high grade, low grade and negative biofilm formers under biofilm assay. The epsA gene was observed in 14 MDR strains (19.17%) of A. baumannii with an amplicon size of 451bp. Co-occurrence of epsA gene was 100% in β-lactam, cephem and folate resistant strains followed by 71.4% among aminoglycosides, 57.1% against carbapenems and 14.2% in fluoroquinolone and efflux pump mediated resistant strains. The findings of the study suggest the co-occurrence of epsA gene mediated biofilm formation among the multidrug resistant strains of A. baumannii. Further studies on the same helps in designing new vaccines and drugs for the prevention and treatment of A. baumannii infections.

Accuracy of an amplicon-sequencing nanopore approach to identify variants in tuberculosis drug-resistance-associated genes

A rapid and accurate diagnostic assay represents an important means to detect Mycobacterium tuberculosis , identify drug-resistant strains and ensure treatment success. Currently employed techniques to diagnose drug-resistant tuberculosis include slow phenotypic tests or more rapid molecular assays that evaluate a limited range of drugs. Whole-genome-sequencing-based approaches can detect known drug-resistance-conferring mutations and novel variations; however, the dependence on growing samples in culture, and the associated delays in achieving results, represents a significant limitation. As an alternative, targeted sequencing strategies can be directly performed on clinical samples at high throughput. This study proposes a targeted sequencing assay to rapidly detect drug-resistant strains of M. tuberculosis using the Nanopore MinION sequencing platform. We designed a single-tube assay that targets nine genes associated with drug resistance to seven drugs and two phylogenetic-determining regions to determine strain lineage and tested it in nine clinical isolates and six sputa. The study’s main aim is to calibrate MinNION variant calling to detect drug-resistance-associated mutations with different frequencies to match the accuracy of Illumina (the current gold-standard sequencing technology) from both culture and sputum samples. After calibrating Nanopore MinION variant calling, we demonstrated 100% agreement between Illumina WGS and our MinION set up to detect known drug resistance and phylogenetic variants in our dataset. Importantly, other variants in the amplicons are also detected, decreasing the recall. We identify minority variants and insertions/deletions as crucial bioinformatics challenges to fully reproduce Illumina WGS results.