Significant Increase In Susceptibility Research Articles

Prospective study of exposure to smoking imagery in films and changes in susceptibility to smoking in a cohort of school students in Southern India.

India has unique tobacco-free film and TV rules designed to prevent tobacco uptake. In this study, we examined the potential influence of exposure to smoking imagery in regionally famous films, on susceptibility to smoke in teenagers enrolled in schools in a district in Southern India. A longitudinal survey of students, in grades 6 to 8 at baseline in 2017 and grades 7 to 9 one year later in 2018, ascertained prospective incident susceptibility to smoking during the study period in relation to baseline exposure to 27 locally popular films with actual or implied smoking imagery. We analyzed linked data from 33676 participants, and 3973 (11.8%) of the adolescents reported incident susceptibility. There was a significant increase in susceptibility to smoking with increasing exposure at baseline to smoking imagery in films on univariable analysis, highest tertile of exposure relative to no exposure (OR=1.4; 95% CI: 1.0 -2.1, ptrend<0.001), and this trend remained significant (p=0.022) after mutual adjustment for recognized confounders, highest vs no exposure (AOR=1.3; 95% CI: 0.9-1.8). We found no statistically significant association between exposure to tobacco-free film rules and change in susceptibility. Prospectively, watching films featuring smoking imagery increases adolescents' vulnerability to smoking. Further research revealed no difference in susceptibility change between youth who saw partially compliant films and those who watched non-compliant films. Our findings, thus, underscore the need to incorporate comprehensive approaches to prevent the inclusion of smoking imagery in films.

Identification of an inhibitory pocket in falcilysin provides a new avenue for malaria drug development

Identification of new druggable protein targets remains the key challenge in the current antimalarial development efforts. Here we used mass-spectrometry-based cellular thermal shift assay (MS-CETSA) to identify potential targets of several antimalarials and drug candidates. We found that falcilysin (FLN) is a common binding partner for several drug candidates such as MK-4815, MMV000848, and MMV665806 but also interacts with quinoline drugs such as chloroquine and mefloquine. Enzymatic assays showed that these compounds can inhibit FLN proteolytic activity. Their interaction with FLN was explored systematically by isothermal titration calorimetry and X-ray crystallography, revealing a shared hydrophobic pocket in the catalytic chamber of the enzyme. Characterization of transgenic cell lines with lowered FLN expression demonstrated statistically significant increases in susceptibility toward MK-4815, MMV000848, and several quinolines. Importantly, the hydrophobic pocket of FLN appears amenable to inhibition and the structures reported here can guide the development of novel drugs against malaria.

RNA interference of NADPH[sbnd]cytochrome P450 increased deltamethrin susceptibility in a resistant strain of the Chagas disease vector Triatoma infestans

The enzyme NADPH-cytochrome P450 reductase (CPR) plays a central role in cytochromes P450 activity. Gene expression analysis of cytochromes P450 and CPR in deltamethrin-resistant and susceptible populations revealed that P450s genes are involved in the development of insecticide resistance in Triatoma infestans. To clarify the role of cytochromes P450 in insecticide resistance, it was proposed to investigate the effect of CPR gene silencing by RNA interference (RNAi) in a pyrethroid resistant population of T. infestans. Silencing of the CPR gene showed a significant increase in susceptibility to deltamethrin in the population analysed. This result support the hypothesis that the metabolic process of detoxification mediated by cytochromes P450 contributes to the decreased deltamethrin susceptibility observed in the resistant strain of T. infestans.

Functional analysis of an overexpressed glutathione S-transferase BdGSTd5 involved in malathion and malaoxon detoxification in Bactrocera dorsalis

Glutathione S-transferases (GSTs) are one of the three detoxification enzyme families. The constitutive and inducible overexpression of GSTs genes plays an important role in insecticide resistance. Previous study showed that malathion resistance was polygenic, and elevated GSTs activity was one of the important factor participating in malathion resistance of Bactrocera dorsalis (Hendel), a serious economic pest worldwide. BdGSTd5 overexpression was inducible upon exposure to malathion. However, the involvement of BdGSTd5 in malathion resistance has not been clarified. In this study, we found that BdGSTd5 sequence harbored the conserved region of delta class GSTs, which were overexpressed in malathion resistant strain of B. dorsalis compared to malathion susceptible strain. The highest mRNA expression level of BdGSTd5 was found in 1-day-old adult, and the levels decreased with aging. The dsBdGSTd5 injection effectively silenced (73.4% reduction) the expression of BdGSTd5 and caused significant increase in susceptibility to malathion with a cumulative mortality increasing of 13.5% at 72 h post malathion treatment (p < 0.05). Cytotoxicity assay demonstrated that BdGSTd5 was capable of malathion detoxification. Molecular docking analysis further indicated the interactive potential of BdGSTd5 with malathion and its toxic oxide malaoxon. The recombinant BdGSTd5 exhibited glutathione-conjugating activity toward 1-chloro-2, 4-dinitrobenzene and malathion and malaoxon metabolic capacity with significant reduction (p < 0.05) of the peak areas by 90.0% and 73.1%, respectively. Taken together, the overexpressed BdGSTd5 contributes to malathion metabolism and resistance, which detoxify the malathion in B. dorsalis via directly depleting malathion and malaoxon.

CRISPR/Cas9-based functional characterization of PxABCB1 reveals its roles in the resistance of Plutella xylostella (L.) to Cry1Ac, abamectin and emamectin benzoate

The identification of functional midgut receptors for pesticidal proteins produced by Bacillus thuringiensis (Bt) is critical for deciphering the molecular mechanism of Bt resistance in insects. Reduced expression of the PxABCB1 gene was previously found to be associated with Cry1Ac resistance in the diamondback moth, Plutella xylostella (L.). To directly validate the potential receptor role of PxABCB1 and its contribution to Bt Cry1Ac toxicity in P. xylostella, we used CRISPR/Cas9 to generate a homozygous knockout ABCB1KO strain with a 5-bp deletion in exon 3 of its gene. The ABCB1KO strain exhibited a 63-fold resistance to Cry1Ac toxin compared to the parental DBM1Ac-S strain. Intriguingly, the ABCB1KO strain also exhibited significant increases in susceptibility to abamectin and emamectin benzoate. No changes in susceptibility to various other Bt Cry proteins or synthetic insecticides were observed. The knockout strain exhibited no significant fitness costs. Overall, our study indicates that PxABCB1 can protect the insect against avermectin insecticides on one hand, while on the other hand it facilitates the toxic effect of the Bt Cry1Ac toxin. The results of this study will help to inform integrated pest management approaches against this destructive pest.

Impact of an antibiotic stewardship program on antibiotic utilization, bacterial susceptibilities, and cost of antibiotics

Antimicrobial misuse is a worldwide issue, and antimicrobial resistance is considered the most challenging aspect of health care. It has been reported that as much as 30–50% of antimicrobials prescribed in hospitals are deemed unnecessary or inappropriate. Antibiotic stewardship programs (ASPs) include policies that apply continuous management of judicious anti-infectious treatment in the clinical setting. Therefore, the objectives of this study were to evaluate the effect of ASPs on antibiotic consumption, the costs of antibiotic expenditure, and the sensitivity of antimicrobials. A retrospective, quasi-experimental study was performed to assess the effect of ASP at An-Najah National University Hospital, a tertiary care hospital in the West Bank, Palestine, over a period of 20 months before and 17 months after the implementation of the ASP. Data on antibiotic consumption were reported monthly as days of therapy per 1000 patient-days and monthly costs (USD/1000 patient-days). A total of 2367 patients who received one or more of the targeted antibiotics (meropenem, colistin and tigecycline) during their hospital stay were included in the study. They have split into two groups: 1710 patients in the pre-ASP group, and 657 patients in the post ASP group. The most significant reduction in DOT per 1000 patient-days was seen with tigecycline, with a percentage of change of − 62.08%. Furthermore, the mean cost of the three antibiotics decreased significantly by 55.5% in the post-ASP phase compared to the pre-ASP phase. After the implementation of ASP, there was a statistically significant increase in susceptibility to meropenem, piperacillin and piperacillin/tazobactam with respect to Pseudomonas aeruginosa. However, changes in mortality rates were not statistically significant (p = 0.057). ASP positively reduced costs and antimicrobial consumption, with no statistically significant effect on the overall mortality rate. However, a long-term evaluation of the ASP's impact is needed to conclude its lasting impact on infection-related mortality and antimicrobial susceptibility pattern.

SG-APSIC1059: Impact of a single intervention as part of a antimicrobial stewardship in a surgical unit of a tertiary-care referral center for neurosurgery

Background: Antimicrobial resistance is a worldwide problem leading to increasing deaths due to intractable infections, especially in postoperative patients who have extended stays in ICUs due to other surgical complications. Carbapenem and colistin resistance has been increasing here; hence, it was decided to monitor and control antibiotic use. In the neurosurgery unit of a quaternary-care hospital in South India, surgical prophylaxis was chosen as less problematic area in which to implement antibiotic stewardship. Objective: To study the difference in the antibiogram pattern of isolates from neurosurgery postoperative patients, before and after the introduction of a surgical antimicrobial prophylaxis policy from the UK National Health Service (NHS). Methods: After the implementation of a new surgical prophylaxis protocol taken from the UK NHS guidelines, we studied its impact by analyzing the antibiogram before implementation (period 1 from January 1, 2020, to December 31, 2020) and after implementation (period 2 from April 1, 2021, to September 30, 2021). This period corresponded to the same number of isolates as the earlier period. Antibiogram criteria: All clinically relevant infections due to the ESKAPE pathogens were included in the antibiogram. The antibiotics analyzed included β-lactams, cephalosporins, β-lactam- lactamase combinations, carbapenems, aminoglycosides, colistin and tigecycline for gram-negative bacilli and penicillin, oxacillin, aminoglycosides, vancomycin, and linezolid for gram-positive cocci. For analysis, the difference was deemed significant according to the criteria stated in CLSI document M39-A4 (4th edition, January 2014). Results: In period 1, 170 isolates were tested, and in period 2, 162 isolates were tested. Among the isolates, Enterococcus spp and Enterobacter spp were too few in number for a comparison. For the gram-negative bacilli, E. coli, Klebsiella pneumoniae, and Acinetobacter baumannii, the differences were significant for the β-lactam–lactamase combinations, carbapenems, and amikacin, with higher susceptibility in period 2. For Staphylococcus aureus, oxacillin, erythromycin, and clindamycin showed a significant increase in susceptibility in period 2. Relevant tables and a graph will be included in the presentation with detailed discussion. Conclusions: Controlled surgical prophylaxis strictly implemented can lead to a significant change in the antibiotic susceptibility pattern among isolates causing healthcare-associated infections among postoperative patients in intensive care units.

Hemocyte response to treatment of susceptible and resistant Asian corn borer (Ostrinia furnacalis) larvae with Cry1F toxin from Bacillus thuringiensis

Midgut receptors have been recognized as the major mechanism of resistance to Cry proteins in lepidopteran larvae, while there is a dearth of data on the role of hemocyte's response to Cry intoxication and resistance development. We aimed at investigating the role of circulating hemocytes in the intoxication of Cry1F toxin in larvae from susceptible (ACB-BtS) and resistant (ACB-FR) strains of the Asian corn borer (ACB), Ostrinia furnacalis. Transcriptome and proteome profiling identified genes and proteins involved in immune-related (tetraspanin and C-type lectins) and detoxification pathways as significantly up-regulated in the hemocytes of Cry1F treated ACB-FR. High-throughput in vitro assays revealed the binding affinity of Cry1F with the tetraspanin and C-type lectin family proteins. We found significant activation of MAPKinase (ERK 1/2, p38α, and JNK 1/2) in the hemocytes of Cry1F treated ACB-FR. In testing plausible crosstalk between a tetraspanin (CD63) and downstream MAPK signaling, we knocked down CD63 expression by RNAi and detected an alteration in JNK 1/2 level but a significant increase in susceptibility of ACB-FR larvae to Cry1F toxin. Information from this study advances a change in knowledge on the cellular immune response to Cry intoxication and its potential role in resistance in a lepidopteran pest.

Quantitative Susceptibility Mapping of Brain Iron Deposition in Patients With Recurrent Depression.

Objective Recurrence is the most significant feature of depression and the relationship between iron and recurrent depression is still lack of direct evidence in vivo. Methods Twenty-one patients with depression and twenty control subjects were included. Gradient-recalled echo, T1 and T2 images were acquired using a 3.0T MRI system. After quantitative susceptibility mapping were reconstructed and standardized, a whole-brain and the regions of interest were respectively analyzed. Results Significant increases in susceptibility were found in multiple recurrent depression patients, which involved several brain regions (frontal lobes, temporal lobe structures, occipital lobes hippocampal regions, putamen, thalamus, cingulum, and cerebellum). Interestingly, no susceptibility changes after treatment compared to pre-treatment (all p>0.05) and no significant correlation between susceptibility and Hamilton Depression Rating Scale were found. Besides, it was close to significance that those with a higher relapse frequency or a longer mean duration of single episode had a higher susceptibility in the putamen, thalamus, and hippocampus. Further studies showed susceptibility across the putamen (ρ2=0.27, p<0.001), thalamus (ρ2=0.21, p<0.001), and hippocampus (ρ2=0.19, p<0.001) were strongly correlated with total course of disease onset. Conclusion Brain iron deposition is related to the total course of disease onset, but not the severity of depression, which suggest that brain iron deposition may be a sign of brain damage in multiple recurrent depression.

Antibacterial Control of an Extremely Low Frequency Electric Field on Escherichia coli

The aim of this study was to investigate the electric field frequency and the time of exposure that causes maximum inhibition of Escherichia coli (E. coli) growth. Methods and Results: Bacterial suspensions were subjected to an extremely low frequency electric field (ELFEF) with a 0.1 Hz interval between 0.2 Hz and 0.4 Hz. The bacterial growth was observed through optical density (OD) readings. OD values were taken every hour for four hours to monitor bacterial growth in both exposed and unexposed samples. The antibiotic susceptibility test was done to determine the difference between the susceptibility of both exposed and unexposed bacterial samples. Structural changes in the exposed bacterial samples were monitored by transmission electron microscope (TEM). The bacterial growth curve revealed a highly significant growth inhibition after being exposed to 0.2 Hz at 2 hours’ exposure time. E. coli suspension exposed to ELFEF at inhibition frequency 0.2 Hz showed a significant increase in susceptibility to antibiotics Keflex, meropenem, and piperacillin-tazobactam. The current data suggest that treating E. coli with 0.2 Hz for 2 hours is an effective, prospective, and novel technique for reducing cellular growth and dramatic alteration in the cell membrane. TEM clarified the great destruction of the bacteria cell wall.

MicroRNA‐mRNA genetic networks in refractive eye development and myopia

AbstractPurposeMyopia is a complex disease controlled by both environmental and genetic factors. Recent genetic studies suggested that the development of myopia is controlled by numerous coding genes. However, the contribution of non‐coding genes, such as microRNAs, is poorly understood. The purpose of this study was to investigate the role of microRNAs in refractive eye development and the development of myopia.MethodsDifferential expression of both microRNAs and mRNAs was analyzed in the retina, RPE, choroid, and sclera of C57BL mice upon induction of experimental myopia with −20 D lenses using RNA‐seq and microRNA‐mRNA genetic networks were reconstructed. We also explored the impact of microRNAs on signaling pathways and evaluated the role of microRNAs in refractive eye development in vivo using conditional Dicer1 knockout mice.ResultsGene expression profiling revealed large number of differential mRNAs and microRNAs in the retina and RPE/choroid/sclera complexes. MicroRNAs were involved in the regulation of several key canonical pathways and biological processes previously implicated in refractive eye development. We then compared visual acuity, contrast sensitivity, and refractive errors in Dicer1 knockouts (Dicer1−/−) and wild‐type littermates (Dicer1+/+) at baseline. We found that loss of miRNAs in the postnatal eyes resulted in a large hyperopic shift in refractive error (+16.3 ± 3.6 D in Dicer1 knockouts versus +4.7 ± 3.0 D in wild‐type animals, p &lt; 1.44 × 10−4), which was accompanied by a small reduction in visual acuity (0.360 ± 0.006 cpd in Dicer1−/− versus 0.403 ± 0.002 cpd in Dicer1+/+, p &lt; 1.16 × 10−7) and contrast sensitivity (12.01 ± 0.27 in Dicer1−/− versus 13.65 ± 0.40 in Dicer1+/+, p &lt; 1.91 × 10−5). Loss of miRNAs also caused a statistically significant increase in susceptibility to form‐deprivation myopia in Dicer1 knockouts compared to wild‐type animals (−19.1 ± 6.8 D in Dicer1−/− versus −9.7 ± 2.7 D in Dicer1+/+, p &lt; 1.51 × 10−4).ConclusionsOur data suggest that microRNAs play significant role in refractive eye development and the development of myopia via modulation of several canonical signaling pathways. MicroRNAs appear to be integrated in the signaling cascade involved in the optical‐defocus‐regulated refractive eye development at multiple levels.

Identification of two ABCC transporters involved in malathion detoxification in the red flour beetle, Tribolium castaneum.

ABC transporters have been suggested to be involved in insecticide detoxification in different insect species mainly based on the indirect observation of transcriptional upregulation of ABC gene expression in response to insecticide exposure. Previous studies performed by us and others in the red flour beetle, Tribolium castaneum, have analyzed the function of TcABCA-C and TcABCG-H genes using RNA interference (RNAi) and demonstrated that specific TcABCA and TcABCC genes are involved in the elimination of the pyrethroid tefluthrin and the benzoylurea diflubenzuron, because gene silencing increased the beetle's susceptibility to the insecticides. In this study, we focused on the potential functions of TcABCA-C genes in detoxification of the pyrethroid cyfluthrin (CF), the organophosphate malathion (MAL) and the diacylhdyazine tebufenozide (TBF). Analysis of transcript levels of selected TcABCA-C genes in response to treatment with these three chemically unrelated insecticides revealed that some genes were particularly upregulated after insecticide treatment. In addition, the ABC inhibitor verapamil synergized significantly the toxicity of MAL but only negligibly CF and TBF toxicities. Finally, silencing of two TcABCC genes by RNAi revealed a significant increase in susceptibility to MAL. In contrast, we did not observe a significant increase in insecticide-induced mortalities when knocking down TcABC genes in larvae treated with CF or TBF, although they were upregulated in response to insecticide treatment. Our results suggest that two pleiotropic ABCC transporters expressed in metabolic and excretory tissues contribute to the elimination of MAL.

Antimicrobial susceptibility patterns of Staphylococcus aureus in a tertiary referral hospital in Nairobi, Kenya

Staphylococcus aureus is a leading cause of hospital and community acquired infections globally. Methicillin-resistant S. aureus (MRSA) prevalence has been reported to be high in various settings and is associated with increased morbidity, mortality and risk of nosocomial outbreaks. Surveillance of prevalence and antibiotic susceptibility patterns is important to ensure appropriate antibiotic prescription. The objective of our study was to establish the prevalence of S. aureus, to identify patterns of susceptibility to commonly used antibiotics and quantify contemporary penicillin resistance among S. aureus. A retrospective study was conducted at the Mater Hospital, Nairobi. The study involved a review of non-duplicate records of specimens analyzed between January 2014 and December 2018. An isolate was categorized as Penicillin susceptible (PSSA) if it was susceptible to Penicillin and Oxacillin, Methicillin susceptible (MSSA) if resistant to Penicillin but susceptible to Oxacillin and Methicillin resistant (MRSA) if resistant to Oxacillin and Penicillin. We present proportions of S. aureus that was PSSA, MSSA and MRSA. Multivariate logistic regression was used to determine the association between the presence of S. aureus isolates and the source of the clinical specimen (inpatient vs. outpatient), age and gender. A total of 659 isolates of S. aureus were analyzed in 5-year period. PSSA was the most prevalent organism seen (60.85%) while MRSA was the least prevalent (0.61%). Most S. aureus were isolated in pus from wound swabs-644 (73. 3%). A significant increase in susceptibility of S. aureus to Penicillin and Amoxicillin-clavulanic acid was observed during the study period. This study demonstrated a high prevalence of Penicillin Sensitive S. aureus and a low prevalence of MRSA. Key words: Staphylococcus aureus, antimicrobial, penicillin.

Organic Hydroperoxide Resistance Gene ohr (VPA1681) Confers Protection against Organic Peroxides in the Presence of Alkyl Hydroperoxide Reductase Genes in Vibrio parahaemolyticus.

The marine foodborne enteropathogen Vibrio parahaemolyticus contains the chief organic peroxide reductases AphC1-AhpC2 and a putative organic hydroperoxide resistance enzyme (Ohr; VPA1681) against different peroxides. This study investigated the function of the Ohr under the presence of AhpC1-AhpC2 in this pathogen by gene mutation. Experimental results demonstrated that the ohr gene product was a weak scavenger of H2O2 only in the mutant strains that lacked the peroxide sensor/regulator oxyR and ahpC1-ahpC2 genes. The Ohr of V. parahaemolyticus was highly effective at scavenging organic peroxide, as demonstrated by assaying the defective changes in the Δohr mutant strain and determining the detoxifying activity of the purified recombinant V. parahaemolyticus Ohrvp protein in the reduced form. The Ohr and AhpC1-AhpC2 exhibited similar functions against organic peroxides; however, only the ΔahpC1ΔahpC2 mutant strain showed a significant increase in susceptibility to several disinfectants, organic acids, and antibiotics compared with the wild-type strain. The transcription of the ohr gene depended on exogenous cumene hydroperoxide (cumene) stress and was markedly enhanced in the ΔohrR (VPA1682) mutant strains. This study revealed the organic hydroperoxide reductase activity of the Ohr in V. parahaemolyticus, and its role probably depends on sophisticated regulation by OhrR. IMPORTANCE Vibrio parahaemolyticus is the most prevalent foodborne pathogen in Taiwan and some other coastal Asian countries, and its antioxidative activity contributes to the tolerance of this bacterium to different environmental stresses. This study reports on the function of the organic hydroperoxide resistance gene (ohr; VPA1681) and its gene regulator, ohrR (VPA1682), in this pathogen. The strain with the ohr gene had effective protection against organic peroxide, and the recombinant Ohrvp was active in its reduced form. The function of Ohr was significant mostly in strains in which the function of AhpC1-AhpC2 was limited. The ohrR repressor of the ohr gene was effective at low concentrations of organic peroxide. Other common Vibrio species that contain homologous ohr, ohrR, ahpC1, and ahpC2 genes, which are phylogenetically close to those of V. parahaemolyticus, may share similar functions to those revealed in this study.

Collagenase Activity of Bromelain Immobilized at Gold Nanoparticle Interfaces for Therapeutic Applications.

Bromelain (Bro) is a multiprotein complex extracted from the pineapple plant Ananas comosus, composed of at least eight cysteine proteases. Bro has a wide range of applications in medicine and industry, where the stability of its active proteases is always a major concern. The present study describes the improvement of stability and gain of specific activity in the enzymatic content of Bro immobilized on gold nanoparticles (GNPs). GNPs were synthesized in situ using Bro as the reducing and stabilizing agents and characterized by surface plasmon resonance and transmission electron microscopy. Consistent with the structural changes observed by circular dichroism analysis, the association with GNPs affected enzyme activity. The active Bro immobilized on GNPs (NanoBro) remained stable under storage and gained thermal stability consistent with a thermophilic enzyme. Proteolytic assays were performed on type I collagen membranes using fluorescence spectroscopy of O-phthaldialdehyde (OPA), changes in the membrane superficial structure, and topography by scanning electron microscopy, FTIR, and scanning laser confocal microscopy. Another characteristic of the NanoBro observed was the significant increase in susceptibility to the inhibitory effect of E-64, indicating a gain in cysteine protease activity. The higher stability and specific activity of NanoBro contributed to the broadening and improvement of Bro applications.

Impact of antifungal stewardship interventions on the susceptibility of colonized Candida species in pediatric patients with malignancy

There is a worldwide concern regarding the antimicrobial resistance and the inappropriate use of antifungal agents, which had led to an ever-increasing antifungal resistance. This study aimed to identify the antifungal susceptibility of colonized Candida species isolated from pediatric patients with cancer and evaluate the clinical impact of antifungal stewardship (AFS) interventions on the antifungal susceptibility of colonized Candida species. Candida species colonization was evaluated among hospitalized children with cancer in a tertiary teaching hospital, Shiraz 2017–2018. Samples were collected from the mouth, nose, urine, and stool of the patients admitted to our center and cultured on sabouraud dextrose agar. The isolated yeasts identified by polymerase chain reaction–restriction fragment length polymorphisms (PCR–RFLP). DNA Extracted and PCR amplification was performed using the ITS1 and ITS4 primer pairs and Msp I enzyme. The broth microdilution method was used to determine the minimum inhibitory concentrations (MICs) for amphotericin B, caspofungin, and azoles. The prevalence of Candida albicans in the present study was significantly higher than other Candida species. Candida albicans species were completely susceptible to the azoles. The susceptibility rate of C. albicans to amphotericin B and caspofungin was 93.1% and 97.1%, respectively. The fluconazole MIC values of Candida albicans decreased significantly during the post-AFS period (P < 0.001; mean difference: 72.3; 95% CI of the difference: 47.36–98.62). We found that ‏52.5% (53/117) of the isolated C. albicans were azole-resistant before AFS implementation, while only 1.5% (2/102) of the isolates were resistant after implementation of the AFS program (P < 0.001). C. albicans fluconazole and caspofungin resistant rate also decreased significantly (P < 0.001) after implementation of the AFS program [26 (32.9%) versus 0 (0.0%) and 11 (10.9%) versus 1 (0.9%), respectively]. Besides, fluconazole use (p < 0.05) and fluconazole expenditure reduced significantly (about one thousand US$ per year) after the AFS program. Our results confirm the positive effect of optimized antifungal usage and bedside intervention on the susceptibility of Candida species after the implementation of the AFS program. C. albicans and C. glabrata exhibited a significant increase in susceptibility after the execution of the AFS program.

Functional analysis of ABCG and ABCH transporters from the red flour beetle, Tribolium castaneum.

ATP-binding cassette transporter (ABC transporter) subfamilies ABCA-C and ABCG-H have been implicated in insecticide detoxification, mostly based on findings of elevated gene expression in response to insecticide treatment. We previously characterized TcABCA-C genes from the model beetle and pest Tribolium castaneum and demonstrated that TcABCA and TcABCC genes are involved in the elimination of diflubenzuron, because RNA interference (RNAi)-mediated gene silencing increased susceptibility. In this study, we focused on the potential functions of TcABCG and TcABCH genes in insecticide detoxification. When we silenced the expression of TcABCG-H genes using RNAi, we noticed a previously unreported developmental RNAi phenotype for TcABCG-4F, which is characterized by 50% mortality and ecdysial arrest during adult moult. When we knocked down the Drosophila brown orthologue TcABCG-XC, we did not obtain apparent eye colour phenotypes but did observe a loss of riboflavin uptake by Malpighian tubules. Next, we determined the expression profiles of all TcABCG-H genes in different tissues and developmental stages and analysed transcript levels in response to treatment with four chemically unrelated insecticides. We found that some genes were specifically upregulated after insecticide treatment. However, when we determined insecticide-induced mortalities in larvae that were treated by double-stranded RNA injection to silence those TcABCG-H genes that were upregulated, we did not observe a significant increase in susceptibility to insecticides. Our findings suggest that the observed insecticide-dependent induction of TcABCG-H gene expression reflects an unspecific stress response, and hence underlines the significance of functional studies on insecticide detoxification. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Synergistic Killing and Re-Sensitization of Pseudomonas aeruginosa to Antibiotics by Phage-Antibiotic Combination Treatment.

Multidrug-resistant (MDR) Pseudomonas aeruginosa infections pose a serious health threat. Bacteriophage–antibiotic combination therapy is a promising candidate for combating these infections. A 5-phage P. aeruginosa cocktail, PAM2H, was tested in combination with antibiotics (ceftazidime, ciprofloxacin, gentamicin, meropenem) to determine if PAM2H enhances antibiotic activity. Combination treatment in vitro resulted in a significant increase in susceptibility of MDR strains to antibiotics. Treatment with ceftazidime (CAZ), meropenem, gentamicin, or ciprofloxacin in the presence of the phage increased the number of P. aeruginosa strains susceptible to these antibiotics by 63%, 56%, 31%, and 81%, respectively. Additionally, in a mouse dorsal wound model, seven of eight mice treated with a combination of CAZ and PAM2H for three days had no detectable bacteria remaining in their wounds on day 4, while all mice treated with CAZ or PAM2H alone had ~107 colony forming units (CFU) remaining in their wounds. P. aeruginosa recovered from mouse wounds post-treatment showed decreased virulence in a wax worm model, and DNA sequencing indicated that the combination treatment prevented mutations in genes encoding known phage receptors. Treatment with PAM2H in combination with antibiotics resulted in the re-sensitization of P. aeruginosa to antibiotics in vitro and a synergistic reduction in bacterial burden in vivo.

Antimicrobial Resistance Among Uropathogens: Surveillance Report From South India

BackgroundUrinary Tract Infection (UTI) is one of the most common infections encountered in clinical practice. Evidence supports that empirical treatment guidelines based on local bacterial spectrum and antimicrobial resistance (AMR) surveillance provide the best clinical results and also prevent the emergence of resistant strains. Antimicrobial resistance has been increasing at an alarming rate throughout the world. This warrants continuous reporting and surveillance of the emergence of AMR among the uropathogens across regions and nations.Materials and methodsA retrospective cross-sectional study using antibiograms of adult patients with culture-proven UTI during January 2011 and January 2017 was done. Comparative analysis was performed between the two study periods for the prevalence, changing trends of antimicrobial resistance, and usage of antimicrobials for testing.ResultsThe commonest organism cultured during each study period was Escherichia coli (56.6% and 51.6%). The most frequently tested antibiotics were ampicillin (97%, 88%), amikacin (85%, 85%), nitrofurantoin (95%, 95%), cephalexin (84%, 93%), and norfloxacin (83%, 83%). There was a significant increase in resistance proportion noted for imipenem (by 29.8%), meropenem (by 18.3%), ertapenem (by 24.9%), ciprofloxacin (by 26.5%), nitrofurantoin (by 11.2%), amikacin (by 8.7%), and cefotaxime (by 7.4%) in 2017 as compared to 2011. A significant increase in susceptibility was seen for tobramycin (by 32.5%), cefepime (by 14.4%), and polymyxin (by 12.6%) in 2017 when compared to 2011.ConclusionOur analysis has shown that there is an alarmingly increasing trend for AMR among uropathogens in this region as compared to developed countries. Data on changing trends of antimicrobial testing and reporting might help in strengthening antimicrobial surveillance.

Evaluation of Guideline Recommendations for Dual Antipseudomonal Therapy in Hospitalized Adults with Pneumonia Using Combination Antibiograms.

Guidelines for pneumonia recommend empiric dual antipseudomonal therapy in patients with specific risk factors. However, there is lack of consensus on when to use dual antipseudomonal therapy as the recommendations are rated as weak, based on low-quality evidence. The objectives of this study were to develop combination antibiograms to assess the susceptibility of Pseudomonas aeruginosa (P. aeruginosa) in respiratory cultures to combinations of empiric antibiotics and to use combination antibiograms to delineate the impact of specific risk factors for which guidelines recommend dual antipseudomonal therapy. A retrospective cohort study was conducted of adults hospitalized with pneumonia with positive respiratory cultures for P. aeruginosa between September 2014 and September 2018. Data collected included demographics, antimicrobial susceptibility results, and risk factors for which guidelines recommend dual antipseudomonal therapy. Combination antibiograms were developed and logistic regression was performed to identify risk factors for nonsusceptibility to beta-lactams. Eight hundred nineteen patients were included and 72% received antibiotics. Beta-lactam susceptibility ranged from 58% to 69% and addition of a fluoroquinolone or aminoglycoside resulted in statistically significant increases in susceptibility. However, only addition of tobramycin or amikacin provided susceptibility rates approaching or exceeding 90% stratified by pneumonia type and risk factors. Presence of guideline-based risk factors generally resulted in reduced susceptibility rates. Logistic regression identified three risk factors associated with nonsusceptibility to beta-lactams: intravenous antibiotics in the previous 90 days, nursing home residence, and mechanical ventilation at onset. The cumulative presence of each additional risk factor affected beta-lactam susceptibility rates, which were 93% in the absence of any risk factors and 39% when all three risk factors co-existed. Risk factors necessitating dual antipseudomonal therapy for pneumonia should be locally validated. When dual antipseudomonal therapy is indicated, tobramycin or amikacin have the best likelihood of providing adequate in vitro activity.