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Bacteria form an intense portion of reading and learning for students enrolled in microbiology education. As a part of the foundational course outline of bacteriology, bacterial classification is a significant topic of discussion. The purpose of our study was to analyze whether bacterial classification can be taught with a phylogenetic tree approach that might be more engaging and beneficial to student learners of microbiology. This methodology is unique compared to the conventional approach applied in introductory lectures of bacteriology that relies on morphology and Gram-staining to classify bacteria. The participants of this study were students enrolled in a two-semester medical school bridge program that offers a Master's degree in Pre-clinical Sciences. We presented bacterial origin and classification in the light of evolution and used a phylogenetic tree to signify clinically relevant groups of bacteria. Students were also taught the traditional bacterial classification using Gram stains and morphology. Both methods of classification were delivered in a didactic classroom session considering equal time spent and utilizing the same format. An online survey was distributed to the students after the session to collect their feedback. The results from the survey showed that 74% of participants would prefer learning bacterial classification using a combined approach that includes both Gram-staining and morphology as well as the phylogenetic tree. When asked if the study of bacterial classification through an evolutionary tree diagram is a clear and concise way of understanding bacteria, 79% of the students either agreed or strongly agreed with this statement. Interestingly, the alternative phylogenetic tree approach was considered more engaging and regarded as a means to expand the clinical knowledge of bacteria by 78% and 71% of the students, respectively. Overall, our study strongly supports the use of tree-based classification as an additional method to improve the learning of medically important groups of bacteria at varying levels of education.
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Malaria is a disease affecting millions of people, especially in Africa, Asia, and South America, and has become a substantial economic burden. Because malaria is contracted through the bite of a mosquito vector, it is very challenging to prevent. Bed nets and insect repellents are used in some homes; others do not have or use them even when available. Thus, treatment measures are crucial to controlling this disease. Artemisinin-based combination therapy (ACT) is currently the first-line treatment for malaria. ACT has been used for decades, but recently, there has been evidence of potential resistance. This threat of resistance has led to the search for possible alternatives to ACT. In sub-Saharan Africa, Azadirachta indica, or simply neem, is a plant used to treat a variety of ailments, including malaria. Neem is effective against one of the more deadly malaria parasites Plasmodium falciparum. Reports show that neem inhibits microgametogenesis of P. falciparum and interferes with the parasite's ookinete development. Although there is substantial in vitro research on the biological activity of A. indica (neem), there is limited in vivo research. Herein, we discuss the in vivo effects of neem on malaria parasites. With A. indica, the future of malaria treatment is promising, especially for high-risk patients, but further research and clinical trials are required to confirm its biological activity.
Résumé Le paludisme est une maladie qui touche des millions de personnes, notamment en Afrique, en Asie et en Amérique du Sud, et est devenu un problème économique majeur fardeau. Le paludisme étant contracté par la piqûre d'un moustique vecteur, il est très difficile à prévenir. Moustiquaires et insectifuges sont utilisés dans certaines maisons ; d'autres ne les possèdent pas ou ne les utilisent pas même lorsqu'ils sont disponibles. Les mesures thérapeutiques sont donc cruciales pour contrôler cette maladie. La thérapie combinée à base d'artémisinine (ACT) constitue actuellement le traitement de première intention contre le paludisme. L'ACT est utilisé depuis des décennies, mais récemment, il y a eu des preuves d'une résistance potentielle. Cette menace de résistance a conduit à la recherche d'alternatives possibles à l'ACT. En Afrique subsaharienne, Azadirachta indica, ou simplement neem, est une plante utilisée pour traiter diverses maladies, dont le paludisme. Le Neem est efficace contre l'un des des parasites du paludisme plus mortels, Plasmodium falciparum. Des rapports montrent que le neem inhibe la microgamétogenèse de P. falciparum et interfere avec le développement de l'ookinète du parasite. Bien qu'il existe d'importantes recherches in vitro sur l'activité biologique d'A. indica (neem), il existe la recherche in vivo est limitée. Nous discutons ici des effets in vivo du neem sur les parasites du paludisme. Avec A. indica, l'avenir du traitement du paludisme est prometteur, en particulier pour les patients à haut risque, mais des recherches et des essais cliniques supplémentaires sont nécessaires pour confirmer son activité biologique. Mots-clés: Azadirachta indica, paludisme, neem, Plasmodium falciparum.
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Antimaláricos , Azadirachta , Malária Falciparum , Malária , Animais , Humanos , Extratos Vegetais/uso terapêutico , Malária/tratamento farmacológico , Plasmodium falciparum , África Subsaariana , Antimaláricos/uso terapêutico , Antimaláricos/farmacologia , Malária Falciparum/tratamento farmacológicoRESUMO
Cyclic dinucleotides (CDNs), such as 2'3'-cGAMP, bind to STING to trigger the production of cytokines and interferons, mainly via activation of TBK1. STING activation by CDN also leads to the release and activation of Nuclear Factor Kappa-light-chain-enhancer of activated B cells (NF-κB) via the phosphorylation of Inhibitor of NF-κB (IκB)-alpha (IκBα) by IκB Kinase (IKK). Beyond the canonical TBK1 or IKK phosphorylations, little is known about how CDNs broadly affect the phosphoproteome and/or other signaling axes. To fill this gap, we performed an unbiased proteome and phosphoproteome analysis of Jurkat T-cell treated with 2'3'-cGAMP or vehicle control to identify proteins and phosphorylation sites that are differentially modulated by 2'3'-cGAMP. We uncovered different classes of kinase signatures associated with cell response to 2'3'-cGAMP. 2'3'-cGAMP upregulated Arginase 2 (Arg2) and the antiviral innate immune response receptor RIG-I as well as proteins involved in ISGylation, E3 ISG15-protein ligase HERC5 and ubiquitin-like protein ISG15, while downregulating ubiquitin-conjugating enzyme UBE2C. Kinases that play a role in DNA double strand break repair, apoptosis, and cell cycle regulation were differentially phosphorylated. Overall, this work demonstrates that 2'3'-cGAMP has a much broader effects on global phosphorylation events than currently appreciated, beyond the canonical TBK1/IKK signaling. SIGNIFICANCE: The host cyclic dinucleotide, 2'3'-cGAMP is known to bind to Stimulator of Interferon Genes (STING) to trigger the production of cytokines and interferons in immune cells via STING-TBK1-IRF3 pathway. Beyond the canonical phosphorelay via the STING-TBK1-IRF3 pathway, little is known about how this second messenger broadly affects the global proteome. Using an unbiased phosphoproteomics, this study identifies several kinases and phosphosites that are modulated by cGAMP. The study expands our knowledge about how cGAMP modulates global proteome and also global phosphorylations.
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NF-kappa B , Proteínas Serina-Treonina Quinases , Humanos , Proteínas Serina-Treonina Quinases/metabolismo , NF-kappa B/metabolismo , Proteômica , Proteoma , Células Jurkat , Interferons , CitocinasRESUMO
Colistin, typically viewed as the antibiotic of last resort to treat infections caused by multidrug-resistant (MDR) Gram-negative bacteria, had fallen out of favor due to toxicity issues. The recent increase in clinical usage of colistin has resulted in colistin-resistant isolates becoming more common. To counter this threat, we have investigated previously reported compounds, HSD07 and HSD17, and developed 13 compounds with more desirable drug-like properties for colistin sensitization against 16 colistin-resistant bacterial strains, three of which harbor the plasmid-borne mobile colistin resistance (mcr-1). Lead compound HSD1624, which has a lower LogDpH7.4 (2.46) compared to HSD07 (>5.58), reduces the minimum inhibitory concentration (MIC) of colistin against Pseudomonas aeruginosa strain TRPA161 to 0.03 µg/mL from 1024 µg/mL (34,000-fold reduction). Checkerboard assays revealed that HSD1624 and analogues are also synergistic with colistin against colistin-resistant strains of Escherichia coli, Acinetobacter baumannii, and Klebsiella pneumoniae. Preliminary mechanism of action studies indicate that HSD1624 exerts its action differently depending on the bacterial species. Time-kill studies suggested that HSD1624 in combination with 0.5 µg/mL colistin was bactericidal to extended-spectrum beta-lactamase (ESBL)-producing E. coli, as well as to E. coli harboring mcr-1, while against P. aeruginosa TRPA161, the combination was bacteriostatic. Mechanistically, HSD1624 increased membrane permeability in K. pneumoniae harboring a plasmid containing the mcr-1 gene but did not increase radical oxygen species (ROS), while a combination of 15 µM HSD1624 and 0.5 µg/mL colistin significantly increased ROS in P. aeruginosa TRPA161. HSD1624 was not toxic to mammalian red blood cells (up to 226 µM).
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Antibacterianos , Colistina , Bactérias Gram-Negativas , Antibacterianos/farmacologia , Bactérias , Colistina/farmacologia , Escherichia coli , Bactérias Gram-Negativas/efeitos dos fármacos , Pseudomonas aeruginosa , Espécies Reativas de Oxigênio , Farmacorresistência Bacteriana MúltiplaRESUMO
Background: Antimicrobial resistance (AMR) is an emerging threat to global health security. Globally, an estimated 700,000 deaths are attributed to AMR annually. Annual deaths due to AMR are projected to reach 10 million by 2050 if current trends persist. Extended Spectrum ß-Lactamases (ESBLs) have the ability to hydrolyse penicillins, cephalosporins up to the third generation, and monobactams, but not ß-lactamase inhibitors such as clavulanic acid. ESBLs undergo continuous mutation, leading to the development of new enzymes with over 400 different ESBL variants described. This study aimed to detect selected CTX-M genes, SHV,and TEM genes in Extended Spectrum Beta-Lactamase producing Klebsiella pneumoniae and Pseudomonas aeruginosa in Jos, Nigeria. Methodology: A total of 110, non-replicated isolates of Klebsiella pneumonia and 125 isolates of Pseudomonas aeruginosa were identified phenotypically from clinical specimens of patients at a tertiary hospital in Jos, North-central Nigeria. The isolates were screened for ESBL production using the disk diffusion method of the Clinical Laboratory Standard Institute (CLSI) breakpoints. Phenotypic confirmation of ESBL production was done using the double-disc synergy test. Multiplex PCR was used to detect ESBL genes. Results: Fifty (45.5%) of the 110 isolates of Klebsiella pneumoniae and 9(7.2%) of the 125 isolates of Pseudomonas aeruginosa were ESBL-positive. Typing of 20 representative ESBL isolates (17 Klebsiella and 3 Pseudomonas spp) showed the presence ofblaCTX-M1, blaCTX-M9, and blaSHV genes in these isolates. All 20 (100%) isolates had the blaCTX-M1 gene. The blaSHV gene was detected in 16(80%) while CTX-M9 was detected in 6(30%) of the isolates studied. Conclusion: The study showed that there is a high prevalence of ESBL genes among isolates ofKlebsiella pneumoniae and Pseudomonas aeruginosa in North-central Nigeria. This emphasizes the need for continuous surveillance and coordinated infection prevention and control to curtail its spread.
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A new class of alkynyl isoquinoline antibacterial compounds, synthesized via Sonogashira coupling, with strong bactericidal activity against a plethora of Gram-positive bacteria including methicillin- and vancomycin-resistant Staphylococcus aureus (S. aureus) strains is presented. HSN584 and HSN739, representative compounds in this class, reduce methicillin-resistant S. aureus (MRSA) load in macrophages, whilst vancomycin, a drug of choice for MRSA infections, was unable to clear intracellular MRSA. Additionally, both HSN584 and HSN739 exhibited a low propensity to develop resistance. We utilized comparative global proteomics and macromolecule biosynthesis assays to gain insight into the alkynyl isoquinoline mechanism of action. Our preliminary data show that HSN584 perturb S. aureus cell wall and nucleic acid biosynthesis. The alkynyl isoquinoline moiety is a new scaffold for the development of potent antibacterial agents against fatal multidrug-resistant Gram-positive bacteria.
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Anti-Infecciosos , Staphylococcus aureus Resistente à Meticilina , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Bactérias , Isoquinolinas/farmacologia , Testes de Sensibilidade Microbiana , Proteoma , Staphylococcus aureusRESUMO
The National Institute of Health (NIH) estimates that the majority of human microbial infections are either linked to or directly caused by bacterial biofilms and these infections are immune to most currently approved FDA drugs. Hence, there is a need for the development of potent antibiotics against biofilms. We have previously shown that pentafluorosulfanyl (SF5)-containing quinoline compounds, which were synthesized via the Povarov reaction, kill persister bacteria (Onyedibe et al. RSC Med Chem, 2021, 12, 1879-1893). Inspired by this earlier discovery, we expanded upon the compounds in the library to identify additional members that could have similar or better potencies, with a goal of increasing the diversity of compounds that could be further developed into therapeutics. Compounds from the Povarov derived SF5-containing compounds inhibited both clinical and laboratory strains of Gram-positive bacteria at minimum inhibitory concentration (MIC) of 0.5 µg/mL to 2 µg/mL. Interestingly, the lead compound, HSD 1919 exhibited rapid bactericidal mode of action against multidrug resistant (MDR) staphylococcal and enterococcal strains such as MRSA and VRE via bacterial membrane disruption. HSD 1919 eradicated persister MRSA in 2 h-8 h. Most remarkably, we found that HSD 1919 (newly identified compound) and HSD 1835 (previously disclosed, Onyedibe et al. RSC Med Chem, 2021, 12, 1879-1893), dispersed preformed MRSA and VRE biofilms at relatively low concentrations (8 µg/mL). Bithionol (at 1 µg/mL) or nitroxoline (at 4 µg/mL) did not appreciably disperse pre-existing biofilms but when combined with HSD 1919 or HSD 1835 (at 0.5-4 µg/mL), preformed MRSA biofilms could be dispersed, highlighting exciting synergy at reasonably low concentrations of the drugs. Biofilm dispersal was verified by scanning electron microscopy (SEM) whilst membrane disruption properties of HSD 1919 were confirmed by both transmission electron microscopy (TEM) and SEM. Further mechanistic studies showed inhibition of DNA, RNA, cell wall and protein synthesis in a macromolecular biosynthesis assay indicating that these compounds inhibit bacteria via multiple mechanisms, which is now being appreciated as an effective way to tackle resistant bacteria. Toxicity studies showed that HSD 1919 was nontoxic in-vitro to mammalian red blood cells at 10X MIC. Herein, we report HSD 1919 and analogs thereof as critical chemical scaffolds, which can be harnessed to develop highly potent antibiofilm therapeutics.
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Staphylococcus aureus Resistente à Meticilina , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Bactérias , Biofilmes , Farmacorresistência Bacteriana Múltipla , Humanos , Mamíferos , Testes de Sensibilidade MicrobianaRESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) infections are still difficult to treat, despite the availability of many FDA-approved antibiotics. Thus, new compound scaffolds are still needed to treat MRSA. The oxadiazole-containing compound, HSGN-94, has been shown to reduce lipoteichoic acid (LTA) in S. aureus, but the mechanism that accounts for LTA biosynthesis inhibition remains uncharacterized. Herein, we report the elucidation of the mechanism by which HSGN-94 inhibits LTA biosynthesis via utilization of global proteomics, activity-based protein profiling, and lipid analysis via multiple reaction monitoring (MRM). Our data suggest that HSGN-94 inhibits LTA biosynthesis via direct binding to PgcA and downregulation of PgsA. We further show that HSGN-94 reduces the MRSA load in skin infection (mouse) and decreases pro-inflammatory cytokines in MRSA-infected wounds. Collectively, HSGN-94 merits further consideration as a potential drug for staphylococcal infections.
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Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Animais , Antibacterianos/química , Camundongos , Testes de Sensibilidade Microbiana , Oxidiazóis/metabolismo , Oxidiazóis/farmacologia , Oxidiazóis/uso terapêutico , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureusRESUMO
Drug-resistant bacterial pathogens still cause high levels of mortality annually despite the availability of many antibiotics. Methicillin-resistant Staphylococcus aureus (MRSA) is especially problematic, and the rise in resistance to front-line treatments like vancomycin and linezolid calls for new chemical modalities to treat chronic and relapsing MRSA infections. Halogenated N-(1,3,4-oxadiazol-2-yl)benzamides are an interesting class of antimicrobial agents, which have been described by multiple groups to be effective against different bacterial pathogens. The modes of action of a few N-(1,3,4-oxadiazol-2-yl)benzamides have been elucidated. For example, oxadiazoles KKL-35 and MBX-4132 have been described as inhibitors of trans-translation (a ribosome rescue pathway), while HSGN-94 was shown to inhibit lipoteichoic acid (LTA). However, other similarly halogenated N-(1,3,4-oxadiazol-2-yl)benzamides neither inhibit trans-translation nor LTA biosynthesis but are potent antimicrobial agents. For example, HSGN-220, -218, and -144 are N-(1,3,4-oxadiazol-2-yl)benzamides that are modified with OCF3, SCF3, or SF5 and have remarkable minimum inhibitory concentrations ranging from 1 to 0.06 µg/mL against MRSA clinical isolates and show a low propensity to develop resistance to MRSA over 30 days. The mechanism of action of these highly potent oxadiazoles is however unknown. To provide insights into how these halogenated N-(1,3,4-oxadiazol-2-yl)benzamides inhibit bacterial growth, we performed global proteomics and RNA expression analysis of some essential genes of S. aureus treated with HSGN-220, -218, and -144. These studies revealed that the oxadiazoles HSGN-220, -218, and -144 are multitargeting antibiotics that regulate menaquinone biosynthesis and other essential proteins like DnaX, Pol IIIC, BirA, LexA, and DnaC. In addition, these halogenated N-(1,3,4-oxadiazol-2-yl)benzamides were able to depolarize bacterial membranes and regulate siderophore biosynthesis and heme regulation. Iron starvation appears to be part of the mechanism of action that led to bacterial killing. This study demonstrates that N-(1,3,4-oxadiazol-2-yl)benzamides are indeed privileged scaffolds for the development of antibacterial agents and that subtle modifications lead to changes to the mechanism of action.
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Antibacterianos , Staphylococcus aureus Resistente à Meticilina , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Benzamidas/farmacologia , Benzamidas/uso terapêutico , Oxidiazóis/farmacologia , Staphylococcus aureusRESUMO
BACKGROUND: Constant exposure of human gingival fibroblasts (HGFs) to oral pathogens trigger selective immune responses. Recently, the activation of immune response to cyclic dinucleotides (CDNs) via STING has come to the forefront. Reports show that other proteins outside the STING-TBK1-IRF3 axis respond to CDNs but a global view of impacted proteome in diverse cells is lacking. HGFs are constantly exposed to bacterial-derived cyclic-di-adenosine monophosphate (c-di-AMP) and cyclic-di-guanosine monophosphate (c-di-GMP). AIM: To understand the response of HGFs to bacterial-derived CDNs, we carried out a global proteomics analysis of HGFs treated with c-di-AMP or c-di-GMP. METHODS: The expression levels of several proteins modulated by CDNs were examined. RESULTS: Interferon signaling proteins such as Ubiquitin-like protein ISG15 (ISG15), Interferon-induced GTP-binding protein Mx1 (MX1), Interferon-induced protein with tetratricopeptide repeats (IFIT) 1 (IFIT1), and (IFIT3) were significantly upregulated. Interestingly, other pathways not fully characterized to be regulated by CDNs, such as necroptosis signaling, iron homeostasis signaling, protein ubiquitination, EIF2 signaling, sumoylation and nucleotide excision repair pathways were also modulated by the bacterial-derived CDNs. CONCLUSION: This study has added to the increasing appreciation that beyond the regulation of cytokine production via STING, cyclic dinucleotides also broadly affect many critical processes in human cells.
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Bacteria persister cells are immune to most antibiotics and hence compounds that are active against persister bacteria are needed. We screened a chemical library of SF5- and SCF3-substituted tetrahydroquinoline compounds, synthesized via the Povarov reaction, for antibacterial activity and identified active compounds that displayed good activities against many Gram-positive bacteria, including persisters. The most potent of these compounds, HSD1835, inhibited the growth of drug-resistant Gram-positive bacterial pathogens (including clinical strains) at concentrations ranging from 1 µg mL-1 to 4 µg mL-1. Several of the SCF3- and SF5-containing compounds were active against methicillin-resistant Staphylococcus aureus (MRSA) and against the two most fatal strains of vancomycin-resistant Enterococcus (VRE), VRE faecalis and VRE faecium. The compounds showed bactericidal activity against stationary phase persister MRSA in time-kill assays. Mechanistic studies showed that HSD1835 acts by disrupting bacterial membranes. Scanning electron microscopy (SEM) was used to confirm bacterial membrane disruption. Interestingly, in a 30 day serial exposure experiment, MRSA remained susceptible to low-dose HSD1835 whilst resistance to ciprofloxacin and mupirocin emerged by day 10. Analogs of HSD1835, which did not bear the SF5 or SCF3 moieties, were inactive against bacteria. Recent reports (G. A. Naclerio, N. S. Abutaleb, K. I. Onyedibe, M. N. Seleem and H. O. Sintim, RSC Med. Chem. 2020, 11, 102-110 and G. A. Naclerio, N. S. Abutaleb, D. Li, M. N. Seleem and H. O. Sintim, J. Med. Chem. 2020, 63(20), 11934-11944) also demonstrated that adding the SF5 or SCF3 groups to a different scaffold (oxadiazoles) enhanced the antibacterial properties of the compounds, so it appears that these groups are privileged moieties that enhance the antimicrobial activities of compounds.
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BACKGROUND: Bloodstream infections (BSI) caused by Enterobacteriaceae show increasing frequency of resistance to third-generation cephalosporin (3GC) antibiotics on the African continent but the mortality impact has not been quantified. METHODS: We used historic data from six African hospitals to assess the impact of 3GC resistance on clinical outcomes in Escherichia coli and Klebsiella pneumoniae BSI. We matched each bacteraemic patient to two uninfected patients. We compared outcomes between 3GC-susceptible and 3GC-resistant BSI and their respective uninfected controls using Cox regression models. RESULTS: For 1431 E. coli BSI patients, we matched 1152 (81%) 3GC-susceptible and 279 (19%) 3GC-resistant cases to 2263 and 546 uninfected inpatient controls. For 1368 K. pneumoniae BSI patients, we matched 502 (37%) 3GC-susceptible and 866 (63%) 3GC-resistant cases to 982 and 1656 uninfected inpatient controls. We found that 3GC-resistant E. coli had similar hazard ratios (HRs) for in-hospital mortality over their matched controls as compared to susceptible infections over their controls (ratio of HRs 1.03, 95% CI 0.73-1.46). Similarly, 3GC-resistance in K. pneumoniae BSI was not associated with mortality (ratio of HR 1.10, 95% CI 0.80-1.52). Estimates of mortality impact varied by site without a consistent pattern. CONCLUSIONS: In a retrospective analysis, including the use of matched uninfected patients, there did not appear to be an impact of 3GC-resistance on mortality in E. coli or K. pneumoniae BSI in African hospitals, as compared with susceptible BSI with equivalent species. Better information on the actual use of antibiotics in treating infections in African hospitals would improve these impact estimates.
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[This corrects the article DOI: 10.1093/jacamr/dlaa130.].
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Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE) have been deemed as serious threats by the CDC. Many chronic MRSA and VRE infections are due to biofilm formation. Biofilm are considered to be between 10-10,000 times more resistant to antibiotics, and therefore new chemical entities that inhibit and/or eradicate biofilm formation are needed. Teichoic acids, such as lipoteichoic acids (LTAs) and wall teichoic acids (WTAs), play pivotal roles in Gram-positive bacteria's ability to grow, replicate, and form biofilms, making the inhibition of these teichoic acids a promising approach to fight infections by biofilm forming bacteria. Here, we describe the potent biofilm inhibition activity against MRSA and VRE biofilms by two LTA biosynthesis inhibitors HSGN-94 and HSGN-189 with MBICs as low as 0.0625 µg/mL against MRSA biofilms and 0.5 µg/mL against VRE biofilms. Additionally, both HSGN-94 and HSGN-189 were shown to potently synergize with the WTA inhibitor Tunicamycin in inhibiting MRSA and VRE biofilm formation.
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Antibacterianos/farmacologia , Biofilmes , Enterococcus faecalis/fisiologia , Lipopolissacarídeos/biossíntese , Staphylococcus aureus Resistente à Meticilina/fisiologia , Ácidos Teicoicos/biossíntese , Antibacterianos/química , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimentoRESUMO
BACKGROUND: The burden of healthcare-associated infection (HAI) is 2 to 18 times higher in developing countries. However, few data are available regarding infection prevention and control (IPC) process indicators in these countries. We evaluated hand hygiene (HH) facilities and compliance amongst healthcare workers (HCW) in a 600-bed healthcare facility in Northcentral Nigeria providing tertiary care service for a catchment population of about 20 million. METHODS: An in-house facility assessment tool and the World Health Organization (WHO) direct observation method were used to assess the HH facilities and compliance, respectively. Factors associated with good compliance were determined by multivariate analysis. RESULTS: The facility survey was carried out in all 46 clinical units of the hospital. 72% of the units had no poster or written policy on HH; 87% did not have alcohol-based hand rubs; 98% had at least one handwash sink; 28% had flowing tap water all day while 72% utilized cup and bucket; and 58% had no hand drying facilities. A total of 406 HH opportunities were observed among 175 HCWs. The overall compliance was 31%, ranging from 18% among ward attendants to 82% among medical students. Based on WHO "5 moments" for HH, average compliance was 21% before patient contact, 23% before aseptic procedure, 63% after body fluid exposure risk, 41% after patient contact and 40% after contact with patients' surrounding. Being a medical student was independently associated with high HH compliance, adjusted odds ratio: 13.87 (1.70-112.88). CONCLUSIONS: Availability of HH facilities and HCW compliance in a large tertiary hospital in Nigeria is poor. Our findings confirm that HCWs seem more sensitized to their risk of exposure to potential pathogens than to the prevention of HAI cross-transmission. Inadequate HH facilities probably contributed to the poor compliance. Specific measures such as improved facilities, training and monitoring are needed to improve HH compliance.
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Infecção Hospitalar/prevenção & controle , Fidelidade a Diretrizes , Higiene das Mãos/métodos , Estudos Transversais , Países em Desenvolvimento , Feminino , Desinfecção das Mãos/métodos , Pessoal de Saúde , Humanos , Controle de Infecções/métodos , Masculino , Nigéria , Centros de Atenção TerciáriaRESUMO
PURPOSE: Cyclic guanosine monophosphate-adenosine monophosphate and other bacterial-derived cyclic di-guanosine monophosphate or cyclic di-adenosine monophosphate trigger innate immune responses through binding to stimulator of interferon genes (STING). Thus in chronic infection, such as in periodontitis, immune cells can be exposed to bacterial DNA and/or cyclic dinucleotides, potentially activating STING to cause inflammation. Thus far the cyclic GMP-AMP synthase-STING- TANK-binding kinase 1 pathway has been well characterized but a global perspective of how the presence or lack of STING affect the proteome is lacking. The aim of this study is to identify macrophage proteins that are affected by STING. EXPERIMENTAL DESIGN: Proteins are extracted from a macrophage cell line harboring STING (RAW-Blue ISG) as well as a STING knockout (STING KO) cell line (RAW-Lucia ISG-KO-STING) and global proteomics analyses are performed. RESULTS: Proteins related to kinase and phosphatase signaling, spliceosome, terpenoid backbone biosynthesis, glycosylation, ubiquitination, and phagocytosis are affected by STING knock out. CONCLUSIONS AND CLINICAL RELEVANCE: STING pathway in macrophages is related to the regulation of several proteins that are known as potent biomarkers of various cancers and autoimmune diseases. Moreover, the relation between STING and phagocytosis is demonstrated for the first time. Further validation studies will help identify molecules and pathways that may function as diagnostic or therapeutic targets.
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Macrófagos/metabolismo , Proteínas de Membrana/metabolismo , Proteômica , Animais , Biomarcadores/metabolismo , Linhagem Celular , Técnicas de Inativação de Genes , Glicosilação , Macrófagos/citologia , Macrófagos/imunologia , Proteínas de Membrana/deficiência , Proteínas de Membrana/genética , Camundongos , Terapia de Alvo Molecular , Fagocitose , Transdução de Sinais , UbiquitinaçãoRESUMO
According to the Centers for Disease Control and Prevention (CDC), methicillin-resistant Staphylococcus aureus (MRSA) affects about 80 000 patients in the US annually and directly causes about 11 000 deaths. Therefore, despite the fact that there are several drugs available for the treatment of MRSA, there is a need for new chemical entities. We previously reported that 1,3,4-oxadiazolyl sulfonamide F6 was bacteriostatic and inhibited MRSA strains with a minimum inhibitory concentration (MIC) of 2 µg mL-1. Here, we report the discovery of trifluoromethoxy (OCF3), trifluoromethylsulfonyl (SO2CF3), trifluoromethylthio (SCF3) and pentafluorosulfanyl (SF5) containing (1,3,4-oxadiazol-2-yl)benzamides exhibiting potent antibacterial activities against MRSA [MIC values as low as 0.06 µg mL-1 against linezolid-resistant S. aureus (NRS 119)]. Interestingly, whereas the OCF3 and SO2CF3 containing oxadiazoles were bacteriostatic, the SCF3 and SF5 containing oxadiazoles were bactericidal. They exhibited a wide spectrum of activities against an extensive panel of Gram-positive bacterial strains, including MRSA, vancomycin-resistant Staphylococcus aureus (VRSA), vancomycin-resistant enterococcus (VRE) and methicillin-resistant or cephalosporin-resistant Streptococcus pneumoniae. Furthermore, compounds 6 and 12 outperformed vancomycin in clearing intracellular MRSA in infected macrophages. Moreover, the tested compounds behaved synergistically or additively with antibiotics used for the treatment of MRSA infections.
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Ectonucleotide pyrophosphatase/phosphodiesterase I (ENPP1) was identified several decades ago as a type II transmembrane glycoprotein with nucleotide pyrophosphatase and phosphodiesterase enzymatic activities, critical for purinergic signaling. Recently, ENPP1 has emerged as a critical phosphodiesterase that degrades the stimulator of interferon genes (STING) ligand, cyclic GMP-AMP (cGAMP). cGAMP or analogs thereof have emerged as potent immunostimulatory agents, which have potential applications in immunotherapy. This emerging role of ENPP1 has placed this "old" enzyme at the frontier of immunotherapy. This review highlights the roles played by ENPP1, the mechanism of cGAMP hydrolysis by ENPP1, and small molecule inhibitors of ENPP1 with potential applications in diverse disease states, including cancer.
Assuntos
Proteínas de Membrana/metabolismo , Inibidores de Fosfodiesterase/farmacologia , Diester Fosfórico Hidrolases/metabolismo , Pirofosfatases/antagonistas & inibidores , Pirofosfatases/metabolismo , Animais , Descoberta de Drogas , Regulação da Expressão Gênica , Humanos , Hidrólise , Proteínas de Membrana/química , Inibidores de Fosfodiesterase/química , Diester Fosfórico Hidrolases/química , Ligação Proteica , Pirofosfatases/química , Transdução de Sinais/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
Staphylococcus aureus can survive both inside and outside of phagocytic and nonphagocytic host cells. Once in the intracellular milieu, most antibiotics have reduced ability to kill S. aureus, thus resulting in relapse of infection. Consequently, there is a need for antibacterial agents that can accumulate to lethal concentrations within host cells to clear intracellular infections. We have identified tetrahydrobenzo[a or c]phenanthridine and tetrahydrobenzo[a or c]acridine compounds, synthesized via a one-flask Povarov-Doebner operation from readily available amines, aldehydes, and cyclic ketones, as potent agents against drug-resistant S. aureus. Importantly, the tetrahydrobenzo[a or c]phenanthridine and tetrahydrobenzo[a or c]acridine compounds can accumulate in macrophage cells and reduce the burden of intracellular MRSA better than the drug of choice, vancomycin. We observed that MRSA could not develop resistance (by passage 30) against tetrahydrobenzo[a or c]acridine compound 15. Moreover, tetrahydrobenzo[c]acridine compound 15 and tetrahydrobenzo[c]phenanthridine compound 16 were nontoxic to red blood cells and were nonmutagenic. Preliminary data indicated that compound 16 reduced bacterial load (MRSA USA300) in mice (thigh infection model) to the same degree as vancomycin. These observations suggest that compounds 15 and 16 and analogues thereof could become therapeutic agents for the treatment of chronic MRSA infections.
Assuntos
Antibacterianos/administração & dosagem , Antibacterianos/síntese química , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Infecções Estafilocócicas/microbiologia , Animais , Antibacterianos/química , Modelos Animais de Doenças , Feminino , Humanos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Estrutura Molecular , Infecções Estafilocócicas/tratamento farmacológicoRESUMO
Halogenated 4-hydroxybenzylidene indolinones have been shown to re-sensitize methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE) to methicillin and vancomycin respectively. The mechanism of antibiotic re-sensitization was however not previously studied. Here, we probe the scope of antibiotic re-sensitization and present the global proteomics analysis of S. aureus treated with GW5074, a 4-hydroxybenzylidene indolinone compound. With a minimum inhibitory concentration (MIC) of 8⯵g/mL against S. aureus, GW5074 synergized with beta-lactam antibiotics like ampicillin, carbenicillin and cloxacillin, the DNA synthesis inhibitor, ciprofloxacin, the protein synthesis inhibitor, gentamicin and the folate acid synthesis inhibitor, trimethoprim. Global proteomics analysis revealed that GW5074 treatment resulted in significant downregulation of enzymes involved in the purine biosynthesis. S. aureus proteins involved in amino acid metabolism and peptide transport were also observed to be downregulated. Interestingly, anti-virulence targets such as AgrC (a quorum sensing-related histidine kinase), AgrA (a quorum sensing-related response regulator) as well as downstream targets, such as hemolysins, lipases and proteases in S. aureus were also downregulated by GW5074. We observed that the peptidoglycan hydrolase, SceD was significantly upregulated. The activity of GW5074 on S. aureus suggests that the compound primes bacteria for the antibacterial action of ineffective antibiotics. SIGNIFICANCE: Antibiotic resistance continues to present significant challenges to the treatment of bacterial infections. Given that antibiotic resistance is a natural phenomenon and that it has become increasingly difficult to discover novel antibiotics, efforts to improve the activity of existing agents are worth pursuing. A few small molecules that re-sensitize resistant bacteria to traditional antibiotics have been described but the molecular details that underpin how these compounds work to re-sensitize bacteria remain largely unknown. In this report, global label-free quantitative proteomics was used to identify changes in the proteome that occurs when GW5074, a compound that re-sensitize MRSA to methicillin, is administered to S. aureus. The identification of pathways that are impacted by GW5074 could help identify novel targets for antibiotic re-sensitization.