Metronidazole-resistant Strains Research Articles

Antigiardial and antiamebic activities of fexinidazole and its metabolites: new drug leads for giardiasis and amebiasis.

The intestinal parasites Giardia lamblia and Entamoeba histolytica are major causes of morbidity and mortality associated with diarrheal diseases. Metronidazole is the most common drug used to treat giardiasis and amebiasis. Despite its efficacy, treatment failures in giardiasis occur in up to 5%-40% of cases. Potential resistance of E. histolytica to metronidazole is an increasing concern. Therefore, it is critical to search for more effective drugs to treat giardiasis and amebiasis. We identified antigiardial and antiamebic activities of the rediscovered nitroimidazole compound, fexinidazole, and its sulfone and sulfoxide metabolites. Fexinidazole is equally active against E. histolytica and G. lamblia trophozoites, and both metabolites were 3- to 18-fold more active than the parent drug. Fexinidazole and its metabolites were also active against a metronidazole-resistant strain of G. lamblia. G. lamblia and E. histolytica cell extracts exhibited decreased residual nitroreductase activity when metabolites were used as substrates, indicating nitroreductase may be central to the mechanism of action of fexinidazole. In a cell invasion model, fexinidazole and its metabolites significantly reduced the invasiveness of E. histolytica trophozoites through basement membrane matrix. A q.d. oral dose of fexinidazole and its metabolites at 10 mg/kg for 3 days reduced G. lamblia infection significantly in mice compared to control. The newly discovered antigiardial and antiamebic activities of fexinidazole, combined with its FDA-approval and inclusion in the WHO Model List of Essential Medicines for the treatment of human African trypanosomiasis, offer decreased risk and a shortened development timeline toward clinical use of fexinidazole for treatment of giardiasis or amebiasis.

High incidence of antibiotic resistance amongst isolates of Helicobacter pylori collected in Nottingham, UK, between 2001 and 2018.

Introduction. Helicobacter pylori is the leading cause of peptic ulcers and gastric cancer. The most common treatment regimens use combinations of two or three antibiotics and a proton pump inhibitor (PPI) to suppress stomach acid. The World Health Organization designated clarithromycin-resistant H. pylori as a high priority pathogen for drug development, due to increasing antibiotic resistance globally.Hypothesis/Gap Statement. There is no routine surveillance of H. pylori primary antimicrobial sensitivities in the UK, and published data are lacking.Aim. This study aimed to characterize antimicrobial sensitivities of isolates collected in Nottingham, UK, between 2001 and 2018.Methodology. Gastric biopsy samples were collected, with informed written consent and ethics approval, from 162 patients attending the Queen's Medical Centre in Nottingham for an upper GI tract endoscopy. Antibiotic sensitivity was assessed using E-Tests and a more cost-effective disc diffusion test.Results. The clarithromycin, amoxicillin and levofloxacin disc diffusion tests provided identical results to E-Tests on a subset of 30 isolates. Disparities were observed in the metronidazole test results, however. In total, 241 isolates from 162 patients were tested using at least one method. Of all isolates, 28 % were resistant to clarithromycin, 62 % to metronidazole and 3 % to amoxicillin, which are used in first-line therapies. For those antibiotics used in second- and third-line therapies, 4 % were resistant to levofloxacin and none of the isolates were resistant to tetracycline. Resistance to more than one antibiotic was found in 27 % of isolates. The frequency of patients with a clarithromycin-resistant strain increased dramatically over time: from 16 % between 2001 and 2005 to 40 % between 2011 and 2018 (P=0.011). For the same time periods, there was also an increase in those with a metronidazole-resistant strain (from 58 to 78 %; P=0.05). The frequencies of clarithromycin and metronidazole resistance were higher in isolates from patients who had previously received eradication therapy, compared to those who had not (40 % versus 77 %, and 80 % versus 92 %, respectively). Of 79 pairs of isolates from the antrum and corpus regions of the same patient's stomach, only six had differences in their antimicrobial susceptibility profiles.Conclusion. Although there was high and increasing resistance to clarithromycin and metronidazole, there was no resistance to tetracycline and the frequencies of amoxicillin and levofloxacin resistance were very low.

Identification, Genome Sequencing, and Characterizations of Helicobacter pylori Sourced from Pakistan.

The stomach's colonization by Helicobacter pylori (H. pylori) results in gastritis, ulcers, and stomach cancer. Frequently, pain is treated with medication, but resistant H. pylori infections are not. Therefore, it is important to find pharmacological targets and improved treatments for resistant H. pylori strains. The aim of the current study was sampling, identification, drug susceptibility testing following genome sequencing and comparative genome-wide analysis of selected H. pylori strains from Pakistan with three representative strains for virulence and drug-resistant characteristics. Based on culture, biochemistry, and molecular biology, 84 strains of H. pylori were identified, which made up 47% of the enrolled cases. Among all H. pylori strains, the highest resistance was reported for metronidazole with 82 H. pylori strains (98%), followed by clarithromycin with 62 resistant strains (74%). Among metronidazole-resistant strains, 38 strains (46%) were also resistant to clarithromycin, contributing 61% of clarithromycin resistant cases. Two strains, HPA1 and HPA2, isolated from 'gastritis' and 'gastric ulcer' patients, respectively, were further processed for WGS. The draft genome sequences of H. pylori strains HPA1 and HPA2 encode 1.66 Mbp and 1.67 Mbp genome size, 24 and 4 contiguous DNA sequences, and 1650 and 1625 coding sequences, respectively. Both the genomes showed greater than 90% similarity with the reference strain H. pylori ATCC 43504/PMSS1. The antibiotic-resistant genes were identified among all the strains with overall similarity above 95%, with minor differences in the sequence similarity. Using the virulent gene data obtained from the Virulence Factor Database, 75 to 85 virulent genes were identified in the five genome assemblies with various key genes such as cytolethal distending toxin (cdt), type IV secretion system, cag PAI, plasticity region, cell-motility- and flagellar-associated genes, neutrophil-activating protein (HP-NAP), T4SS effector cytotoxin-associated gene A (cagA), and urease-associated genes ureA and ureB, etc. Sequence similarity between the virulence factors found in this study and reference genes was at least 90%. In summary, the results of our study showed the relationship between clinical results and specific H. pylori strains' (HPA1 and HPA2) genetics such as antibiotic resistance and specific virulence factors. These findings provide valued understanding of the epidemiology of H. pylori-associated diseases. Moreover, identification and genomics analysis have provided insights into the epidemiology, genetic diversity, pathogenicity, and potential drug resistance genes of H. pylori strains, offering a foundation for developing more targeted and effective medical interventions, including anti-virulent medications.

Synthesis and Biological Evaluation of New Nitroimidazole Derivatives as Anti-Helicobacter pylori Agents Against Metronidazole-Resistant Strains

: Since several Helicobacter pylori strains have become resistant to metronidazole, new nitroimidazole derivatives based on metronidazole were designed and synthesized with different substituents on imidazole nitrogen. The activity of the synthesized compounds was evaluated against 20 clinically isolated metronidazole-resistant H. pylori strains. Some synthesized compounds were effective against those metronidazole-resistant H. pylori strains. Three compounds exhibited the most potent inhibitory activities (MIC50 = 8 µg/mL and MIC90 = 16 µg/mL).

Comparative Study of the Effect of Sophora alopecuroides Plant Extract on Trichomonas vaginalis Parasite In Vitro

Background: Trichomoniasis caused by Trichomonas vaginalis is considered one of the most important worldwide non-viral sexually transmitted infections. The remaining clinical symptoms of the disease after treatment with metronidazole confirm the presence of metronidazole-resistant strains. Objectives: Therefore, the present study aimed to investigate the inhibitory effect of the extract of the root and leaf of the Sophora alopecuroides plant on the growth and inhibition of the growth of T. vaginalis parasite. Methods: Aqueous and alcoholic extracts of S. alopecuroides plant roots and leaves with concentrations of 0.5, 1, 2, 4, and 5 mg/mL, as well as metronidazole were exposed to 105 parasites and mouse macrophage cells in 24 and 48 hours. To determine the toxicity of the extract on the cells, mice peritoneal cells were used for the 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyl-2H-tetrazolium bromide test. The half-maximal inhibitory concentration and 50% cytotoxic concentration values were evaluated by PRISM GraphPad software, and analysis of variance and t test were employed for statistical comparisons by SPSS-23. Results: The aqueous-alkaline compounds of the root of the S. alopecuroides plant demonstrated a promising effect on inhibiting parasite growth, but the therapeutic index of the aqueous extract of its leaves was less effective than the rest of the extracts and metronidazole. After 24 hours, at a concentration of 2.5%, the aqueous extract of the root had the most effect with 69.4%, and the aqueous extract of the leaf had the least effect with 34.68% of growth inhibition. However, none of the extracts had a greater inhibitory effect than metronidazole, but after 48 hours, the effect of the extract caused more inhibition due to time. Conclusion: Overall, the aqueous and alcoholic extracts of the leaves and roots of the S. alopecuroides plant had suitable anti-trichomonas effects. In addition, the aqueous leaf extract had a good effect with the least toxicity. Considering that this research was performed for the first time, to generalize the results, extensive research is needed in in vivo conditions.

The antimicrobial peptides LL-37, KR-20, FK-13 and KR-12 inhibit the growth of a sensitive and a metronidazole-resistant strain of Trichomonas vaginalis.

The parasite Trichomonas vaginalis is the aetiologic agent of trichomoniasis, the most common non-viral sexually transmitted disease worldwide. This infection often remains asymptomatic and is related to several health complications. The traditional treatment for trichomoniasis uses drugs of the 5-nitroimidazole family, such as metronidazole; however, scientific reports indicate an increasing number of drug-resistant strains. Antimicrobial peptides could be an alternative or complementary treatment. In this sense, one attractive candidate is the human cathelicidin, being LL-37 its active form. LL-37 possesses microbicidal activity against many microorganisms such as bacteria, Candida albicans, and Entamoeba histolytica. Shorter sequences derived from this peptide, such as KR-20, FK-13 and KR-12, have been shown to possess a higher microbicidal effect than LL-37. In this study, we determined the activity of LL-37 and its derivatives against T. vaginalis, which was unknown. The results showed that the four peptides (LL-37, KR-20, FK-13-NH2 and KR-12) decreased the viability of T. vaginalis on a 5-nitroimidazole-sensitive and a 5-nitroimidazole-resistant strain; however, KR-20 was the most effective peptide, followed by FK-13-NH2. Low concentrations of all peptides showed a better effect when combined with metronidazole in the sensitive and resistant T. vaginalis strains. These results are promising for potential future therapeutic uses.

Efficacy of bismuth for antibiotic-resistant Helicobacter pylori strains eradication: A systematic review and meta-analysis.

Antibiotic resistance of Helicobacter pylori (H.pylori) is increasing worldwide, and bismuth quadruple therapy has been recommended as a first-line regimen in many areas. This study aimed to investigate whether bismuth would improve the eradication rate (ER) of clarithromycin-/metronidazole-/levofloxacin-resistant H.pylori strains and how much additional efficacy bismuth could achieve. PubMed, EMBASE, Web of Science, and Cochrane Central databases for randomized controlled trials were systematically searched by two independent reviewers until 15 January 2022. Pooled ERs of clarithromycin-/metronidazole-/levofloxacin-resistant H.pylori strains were compared between bismuth-containing and non-bismuth therapies. Pooled risk ratios (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model. Eight studies enrolling 340 individuals were included. The RRs of pooled ERs compared between bismuth-containing and non-bismuth therapies were 1.83 for clarithromycin-resistant strains (95% CI 1.16-2.89, pooled ER: 76.9% vs. 36.6%, p=.009, I2 =0%), 1.39 for metronidazole-resistant strains (95% CI 1.09-1.78, pooled ER: 86.8% vs. 60.9%, p=.008, I2 =37%), 2.75 for dual clarithromycin/metronidazole-resistant strains (95% CI 1.01-7.52, pooled ER: 76.9% vs. 18.2%, p=.05, I2 =0%), and 1.04 for levofloxacin-resistant strains (95% CI 0.56-1.93, pooled ER: 63.4% vs. 54.3%, p=.90; I2 =60%). Bismuth significantly increased the ERs of clarithromycin-, metronidazole-, and dual-resistant strains by 40%, 26%, and 59%, respectively. Subgroup analysis of treatment duration showed that the significantly higher eradication rate for antibiotic-resistant strains in bismuth-containing therapy than non-bismuth therapy was only observed in 14-day treatment regimens and not in 7-day regimens (p=.02 and .17, respectively). Bismuth was most effective in improving the ERs of dual-resistant H.pylori strains, followed by clarithromycin- and metronidazole-resistant strains. Prolonged treatment duration might effectively improve the efficacy of bismuth in overcoming antibiotic resistance.

Exploratory toxicology studies of 2,3-substituted imidazo[1,2-a]pyridines with antiparasitic and anti-inflammatory properties.

Trichomoniasis and amoebiasis are neglected diseases and still remain as a global health burden not only for developing countries, from where are endemic, but also for the developed world. Previously, we tested the antiparasitic activity of a number of imidazo[1,2-a]pyridine derivatives (IMPYs) on metronidazole-resistant strains of Entamoeba Hystolitica (HM1:IMSS), and Trichomonas Vaginalis (GT3). Their anti-inflammatory activity was also evaluated. The present work is a part of a project whose aim is to find new alternatives to standard treatments for these maladies, and to address the current concern of emerging resistant parasite strains. Here we report a non-clinical study focused on exploratory toxicology assays of seven IMPYs that showed the best antiparasitic and/or anti-inflammatory properties. Acute, and subacute toxicity tests were carried out. After 14-day oral treatment, liver and kidney functionality assays in combination with chemometric methods were implemented to detect hepatic and/or kidney damage. Some compounds produced off-target effects. Vehicle effects were also detected. However, no signs of hepatic or renal toxicity were observed for any IMPY. These compounds can continue non-clinical evaluations, and if possible, clinical trials as new candidates to treat trichomoniasis and amoebiasis, and inflammatory diseases. Further studies are also needed to fully elucidate a proposed dual effect that may exert these molecules against trichomoniasis and amoebiasis, which may also signify a novel mechanism of action to treat these infections.

Evaluation of Susceptibility of the Human Pathogen Helicobacter pylori to the Antibiotic Capreomycin.

Helicobacter pylori infection causes gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue lymphoma, and gastric cancer and can also promote thrombosis. It is estimated that approximately 4.5 billion individuals are infected, thus rendering H. pylori the most prevalent microbial pathogen. Currently established regimes for antibiotic treatment are massively challenged by increasing drug resistance and the development of novel antimicrobial therapies is urgently required. The antibiotic capreomycin is clinically used against multiple drug-resistant strains of Mycobacterium tuberculosis. It targets the complex between TlyA, a hemolysin- and RNA-binding protein, and the bacterial rRNA. In this study we have explored the possible antibacterial effects of capreomycin against several strains of H. pylori and found only moderate activity which was comparable to metronidazole-resistant strains. Molecular docking of capreomycin to TlyA proteins from H. pylori and M. tuberculosis identified several residues within TlyA which interact with the drug; however, binding affinities of H. pylori– TlyA for capreomycin appear to be higher than those of Mycobacterium– TlyA. The data suggest that capreomycin may warrant further investigations into its potential use as antibiotic against H. pylori.

An Unusual U2AF2 Inhibits Splicing and Attenuates the Virulence of the Human Protozoan Parasite Entamoeba histolytica.

E. histolytica is the etiological agent of intestinal amebiasis and liver abscesses, which still poses public health threat globally. Metronidazole is the drug of choice against amebiasis. However, metronidazole-resistant amoebic clinical isolates and strains have been reported recently, challenging the efforts for amebiasis eradication. In search of alternative treatments, E. histolytica transcriptomes have shown the association of genes involved in RNA metabolism with the virulence of the parasite. Among the upregulated genes in amoebic liver abscesses are the splicing factors EhU2AF2 and a paralog of EhSF3B1. For this reason and because EhU2AF2 contains unusual KH-QUA2 (84KQ) motifs in its lengthened C-terminus domain, here we investigated how the role of EhU2AF2 in pre-mRNA processing impacts the virulence of the parasite. We found that 84KQ is involved in splicing inhibition/intron retention of several virulence and non-virulence-related genes. The 84KQ domain interacts with the same domain of the constitutive splicing factor SF1 (SF1KQ), both in solution and when SF1KQ is bound to branchpoint signal RNA probes. The 84KQ–SF1KQ interaction prevents splicing complex E to A transition, thus inhibiting splicing. Surprisingly, the deletion of the 84KQ domain in EhU2AF2 amoeba transformants increased splicing and enhanced the in vitro and in vivo virulence phenotypes. We conclude that the interaction of the 84KQ and SF1KQ domains, probably involving additional factors, tunes down Entamoeba virulence by favoring intron retention.

Synthesis of new 2-(5-(5-nitrofuran-2-yl)-1,3,4-thiadiazol-2-ylimino)thiazolidin-4-one derivatives as anti-MRSA and anti-H. pylori agents

In this work, we have synthesized twenty five new 2-(5-(5-nitrofuran-2-yl)-1,3,4-thiadiazol-2-ylimino)thiazolidin-4-one derivatives bearing an aryl or heteroaryl methylene group on position 5 of thiazolidinone and evaluated their antimicrobial activity against Gram-positive and -negative bacteria as well as three metronidazole resistant Helicobacter pylori strains. Most of the compounds were very potent towards tested Gram-positive bacteria and showed an antibacterial efficacy substantially greater than ampicillin as the reference drug. However, no effectiveness was observed for the Gram-negative microorganisms. The compounds 9, 20 and 29 exhibited strong antimicrobial activity against Helicobacter pylori strains (inhibition zone > 30 mm) in 100 μg/disc and (inhibition zone > 20 mm) in 50 μg/disc. Taking these findings together, it seems that these potent antibacterial derivatives could be considered as promising agents for developing new anti-infectious drugs against microorganisms resistant to currently available antibiotics.Graphical

Metronidazole-resistant Clostridioides difficile: genomic and transcriptomic traits acquired under in-vitro metronidazole induction

Decreased effectiveness of metronidazole for the treatment of Clostridioides difficile infection has been documented. One reason for this is that levels of metronidazole in the colon are generally low; therefore, a modest increase in the minimum inhibitory concentration of metronidazole for C. difficile may result in an insufficient therapeutic concentration. Due to the lack of efficient genetic manipulation tools for C. difficile strains, the resistance mechanism is largely unknown. In this study, a metronidazole-resistant strain (SH182IR) was acquired by in-vitro induction with metronidazole from a clinical metronidazole-heteroresistant strain (SH182), and the genomic and transcriptional changes were investigated through whole-genome sequencing and RNA-seq. The morphology of the two strains was studied by transmission electron microscopy, and the roles of drug efflux pumps in metronidazole resistance were determined by inhibition assay. Genomic analysis showed that the ferrous iron transporter feoB3 was truncated in SH182IR, indicating that feoB3 contributed to the metronidazole resistance of C. difficile. RNA-seq analysis showed that genes involved in peptidoglycan synthesis, efflux pumps and metronidazole reductive action were expressed differentially between the two strains. Further cell imaging confirmed that cell wall thickness was significantly greater in SH182IR. The efflux pump inhibitor test showed that addition of reserpine or cyanide 3-chlorophenylhydrazone reduced metronidazole resistance in SH182IR, thus proving the role of efflux pumps in metronidazole resistance. These results found an association between genomic variation and metronidazole resistance in C. difficile, and show that metronidazole resistance in C. difficile is multi-factorial, involving metronidazole metabolism, cell wall thickness and efflux pumps. These findings will help improve knowledge and understanding of metronidazole resistance of C. difficile.

Lupeol acetate isolated from Chrysophyllum cainito L. fruit as a template for the synthesis of N-alkyl-arylsulfonamide derivatives and their synergistic effects with metronidazole against Trichomonas vaginalis

Pentacyclic triterpenes are found in a great variety of natural products and constitute an organic template for the development of new derivative compounds with therapeutic applications. In the present work, lupeol acetate isolated from Chrysophyllum cainito L. fruit was used as a template for the synthesis of novel N-alkyl-arylsulfonamide derivatives, and their synergistic effects with metronidazole against strains of Trichomonas vaginalis were tested. A library of 18 derivatives was synthesized. Ten compounds exhibited an IC50 < 100 μM against a metronidazole-sensitive strain of T. vaginalis. Only seven of these compounds (12, 15, 18-22) also showed activity against metronidazole-resistant strains. The compounds 20 (N-cyclohexyl-p-chlorobenzenesulfonamidolupeol acetate) and 22 (N-cyclohexyl-p-nitrobenzenesulfonamidolupeol acetate) exhibited a similar IC50 against both susceptible and resistant T. vaginalis strains and enhanced the efficacy of metronidazole in a partial and total synergistic way, respectively. These data provided evidence of the trichomonicidal effect of N-alkyl-arylsulfonamide derivatives of lupeol acetate, representing highly promising novel antiparasitic agents.

Correlation Analysis between the Characteristics of Helicobacter pylori Resistance and the Antibiotic Use Density in a Hospital from 2012 to 2018.

Objective To explore the correlation between the resistance characteristics of Helicobacter pylori (HP) and antibiotic use density (AUD) in a hospital from 2012 to 2018. Methods HP strains isolated from Chinese PLA General Hospital from 2012 to 2018 were collected to analyze the drug resistance of clarithromycin, levofloxacin, amoxicillin, and metronidazole, and their correlation with the AUD of the outpatient department and inpatient department was analyzed, respectively. Results From 2012 to 2018, metronidazole-resistant strains accounted for the largest proportion, followed by clarithromycin and levofloxacin, and amoxicillin-resistant strains accounted for the least. In 2012–2018, the resistance rate of clarithromycin, levofloxacin, amoxicillin, and metronidazole has basically increased year by year; from 2012 to 2018, the highest outpatient AUD in a hospital was amoxicillin, followed by clarithromycin and levofloxacin, metronidazole was the lowest, and the inpatient AUD from high to low was levofloxacin, metronidazole, amoxicillin, and clarithromycin. The drug resistance rate of HP in the hospital from 2012 to 2018 was positively correlated with the AUD of clarithromycin (r = 0.884, P=0.017) and levofloxacin (r = 0.934, P=0.002) in the outpatient department. Conclusions Helicobacter pylori has the strongest resistance to metronidazole and the worst resistance to amoxicillin in the hospital from 2012 to 2018, being related to the intensity of clarithromycin and levofloxacin in the outpatient department. It may provide certain reference significance for the clinical treatment of Helicobacter pylori.

Antibacterial Effects of Disulfiram in Helicobacter pylori.

BackgroundHelicobacter pylori infection poses a risk of the occurrence of gastrointestinal diseases, such as gastric cancer. Its incidence rate is significantly reduced by eradication, and thereby, eradication therapy is generally performed. Disulfiram is an oral prescription drug mainly used for the treatment of alcohol dependence. In recent years, reports have been made on its anticancer and antibacterial effects, and thus, it has recently become an interesting subject. This study aimed to examine the antibacterial activity of disulfiram, investigate the presence or absence of its antibacterial activity on H. pylori, and determine whether it could be a new bactericidal drug against drug-resistant H. pylori.Materials and MethodsDrug-sensitive strains of H. pylori and amoxicillin-resistant, clarithromycin-resistant, and metronidazole-resistant strains were used, and a growth inhibition test of H. pylori using disulfiram was performed. Furthermore, the expression of urease, vacuolating cytotoxin A (VacA), and CagA, the virulence proteins of H. pylori, was quantitatively analyzed using the Western blotting method. In addition, for H. pylori used in this study, the 16SrDNA sequence, a ribosomal gene involved in protein production, was analyzed to examine the presence or absence of gene mutation.ResultsDisulfiram suppressed the growth of 7 out of 12 H. pylori strains at 1 µg/mL, and no correlation was observed between their susceptibility/resistance to current eradication antimicrobial drugs and disulfiram resistance. Disulfiram reduced the expression levels of urease, VacA, and CagA proteins. H. pylori, which showed resistance to disulfiram, tended to have fewer gene deletions/insertions in the 16S rDNA sequence; however, no specific mutation was detected.ConclusionDisulfiram has a bactericidal effect on H. pylori at low concentrations, suggesting that it can be used as a supplement for current H. pylori eradication drugs.

Helicobacter pylori Antimicrobial Resistance and Gene Variants in High- and Low-Gastric-Cancer-Risk Populations.

Colombia, South America has one of the world's highest burdens of Helicobacter pylori infection and gastric cancer. While multidrug antibiotic regimens can effectively eradicate H. pylori, treatment efficacy is being jeopardized by the emergence of antibiotic-resistant H. pylori strains. Moreover, the spectrum of and genetic mechanisms for antibiotic resistance in Colombia is underreported. In this study, 28 H. pylori strains isolated from gastric biopsy specimens from a high-gastric-cancer-risk (HGCR) population living in the Andes Mountains in Túquerres, Colombia and 31 strains from a low-gastric-cancer-risk (LGCR) population residing on the Pacific coast in Tumaco, Colombia were subjected to antibiotic susceptibility testing for amoxicillin, clarithromycin, levofloxacin, metronidazole, rifampin, and tetracycline. Resistance-associated genes were amplified by PCR for all isolates, and 29 isolates were whole-genome sequenced (WGS). No strains were resistant to amoxicillin, clarithromycin, or rifampin. One strain was resistant to tetracycline and had an A926G mutation in its 16S rRNA gene. Levofloxacin resistance was observed in 12/59 isolates and was significantly associated with N87I/K and/or D91G/Y mutations in gyrA Most isolates were resistant to metronidazole; this resistance was significantly higher in the LGCR (31/31) group compared to the HGCR (24/28) group. Truncations in rdxA and frxA were present in nearly all metronidazole-resistant strains. There was no association between phylogenetic relationship and resistance profiles based on WGS analysis. Our results indicate H. pylori isolates from Colombians exhibit multidrug antibiotic resistance. Continued surveillance of H. pylori antibiotic resistance in Colombia is warranted in order to establish appropriate eradication treatment regimens for this population.

Anti-Helicobacter pylori Effects of Propolis Ethanol Extract on Clarithromycin and Metronidazole Resistant Strains

Antimicrobial resistance for Helicobacter pylori infection still become problem in Indonesia especially for metronidazole and clarithromycin resistance that is commonly used in the national regiment therapy. Finding a new antimicrobial agent against this bacterium is still a challenge to face. Propolis extract is well known substance which has antimicrobial effect against some gram-negative bacteria. However, the effect against H. pylori remain unknown. We analysed the antimicrobial effect of propolis extract against H. pylori in clarithromycin and metronidazole Resistant Strains. Anti-H. pylori effect of ethanol propolis extract was tested on 10 types of H. pylori strains isolated from dyspeptic patients in Indonesia. Ethanol propolis extracts (PRO) show inhibitory activity at concentrations of 5% and 10% on all strains H. pylori. Determination minimum inhibitory concentration (MIC) value of propolis extract used microdilution method, the MIC values were in the range of 1024-8192 µg/mL. Determination of the minimum bactericidal concentration (MBC) value is performed by scratch method based on the results of the microdilution test and produces an MBC value in the range of 1024 - 16348 µg/mL. The required concentration of propolis extract for the bactericidal effect against H. pylori was the same or eight-fold higher than the corresponding value. The combination of propolis extract and metronidazole based through paper tape method showed an additive effect, as well as the combination of propolis extract and clarithromycin. This extract might be can become alternative treatment against H. pylori infection that resistance for metronidazole and clarithromycin treatment

Molecular characterization of metronidazole resistant Bacteroides strains from Kuwait

Eleven metronidazole resistant Bacteroides and one newly classified Phocaeicola dorei strain from Kuwait were investigated for their resistance mechanisms and the emergence of their resistant plasmids. All but one strain harbored nimE genes on differently sized plasmids. Of the 11 nimE genes, 9 were preceded by full copies of the prototype ISBf6 insertion sequence element, one carried a truncated ISBf6 and one was activated by an additional copy of IS612B. Nucleotide sequencing results showed that the nimE ISBf6 distances were constant and all five different plasmids shared a common region, suggesting that (i) the nimE-ISBf6 configuration was inserted into an undisclosed common genetic element, (ii) over time, this common element was mutated by insertions and deletions, spreading the resultant plasmids. Of the 10 B. fragilis strains in this collection, 6 were also cfiA-positive, one with full imipenem resistance, indicating a tendency for multidrug resistance (MDR) among such isolates. The significant number of metronidazole resistant Bacteroides spp. and P. dorei strains with the MDR phenotype warns of difficulties in treatment and suggests promoting adherence to antibiotic stewardship recommendations in Kuwait.

Eradication Rates for Esomeprazole and Lansoprazole-Based 7-Day Non-Bismuth Concomitant Quadruple Therapy for First-Line Anti-Helicobacter pylori Treatment in Real World Clinical Practice.

PurposeNon-bismuth concomitant quadruple therapy is commonly administered in Taiwan, achieving an acceptable efficacy as a first-line anti-Helicobacter pylori treatment. This study compared the eradication rates between esomeprazole- and lansoprazole-based non-bismuth concomitant quadruple therapy for first-line anti-H. pylori treatment.Patients and MethodsThis study included 206 H. pylori-infected naïve patients between July 2016 and February 2019. The patients were prescribed with either a 7-day non-bismuth containing quadruple therapy (esomeprazole, 40 mg twice daily; amoxicillin, 1 g twice daily; and metronidazole, 500 mg twice daily; and clarithromycin, 500 mg twice daily for 7 days [EACM group]; lansoprazole, 30 mg twice daily; amoxicillin, 1 g twice daily; metronidazole, 500 mg twice daily; and clarithromycin, 500 mg twice daily [LACM group]). Then, the patients were asked to perform urea breath tests 8 weeks later.ResultsThe eradication rates in the EACM group were 86.1% (95% confidence interval [CI], 77.8%–92.2%) and 90.6% (95% CI, 82.9%–95.6%) in the intention-to-treat (ITT) and the per-protocol (PP) analyses, respectively. Moreover, the eradication rates in the LACM group were 90.1% (95% CI, 82.6%–95.2%) and 92.6% (95% CI, 85.5%–96.9%) in the ITT and the PP analyses, respectively. Consequently, the LACM group exhibited more diarrhea patients than the EACM group (7.1% versus 1.0%, p = 0.029), but all symptoms were mild. Univariate analysis in this study showed that metronidazole-resistant strains were the clinical factor affecting the eradications (95.3% versus 78.9%, p = 0.044). Moreover, a trend was observed in dual clarithromycin- and metronidazole-resistant strains (91.5% versus 66.7%, p = 0.155).ConclusionThe eradication rates between esomeprazole and lansoprazole-based non-bismuth concomitant quadruple therapy for first-line H. pylori treatment were similar in this study. Both could achieve a > 90% report card in the PP analysis.

Molecular Epidemiology and Risk Factors of Clostridium difficile ST81 Infection in a Teaching Hospital in Eastern China.

BackgroundThe prevalence of Clostridium difficile causes an increased morbidity and mortality of inpatients, especially in Europe and North America, while data on C. difficile infection (CDI) are limited in China.MethodsFrom September 2014 to August 2019, 562 C. difficile isolates were collected from patients and screened for toxin genes. Multilocus sequence typing (MLST) and antimicrobial susceptibility tests by E-test and agar dilution method were performed. A case group composed of patients infected with sequence type (ST) 81 C. difficile was compared to the non-ST81 infection group and non CDI diarrhea patients for risk factor and outcome analyses.ResultsThe incidence of inpatients with CDI was 7.06 cases per 10,000 patient-days. Of the 562 C. difficile isolates, ST81(22.78%) was the predominant clone over this period, followed by ST54 (11.21%), ST3 (9.61%), and ST2 (8.72%). Toxin genotype tcdA+tcdB+cdt- accounted for 50.18% of all strains, while 29.54% were tcdA-tcdB+cdt- genotypes. Overall, no isolate was resistant to vancomycin, teicoplanin or daptomycin, and resistance rates to meropenem gradually decreased during these years. Although several metronidazole-resistant strains were isolated in this study, the MIC values decreased during this period. Resistance rates to moxifloxacin and clindamycin remained higher than those to the other antibiotics. Among CDI inpatients, longer hospitalization, usage of prednisolone, suffering from chronic kidney disease or connective tissue diseases and admission to emergency ward 2 or emergency ICU were significant risk factors for ST81 clone infection. All-cause mortality of these CDI patients was 4.92%(n=18), while the recurrent cases accounted for 5.74%(n=21). The 60-day mortality of ST81-CDI was significantly higher than non-ST81 infected group, while ST81 also accounted for most of the recurrent CDI cases.ConclusionThis study revealed the molecular epidemiology and risk factors for the dominant C. difficile ST81 genotype infection in eastern China. Continuous and stringent surveillance on the emerging ST81 genotype needs to be initiated.