Review of Clinically and Epidemiologically Relevant Coagulase-Negative Staphylococci in Africa

Coagulase-negative staphylococci (CoNS) have engendered substantial interest in recent years as pathogenic causes of infections in both human and veterinary medicine, especially in the immunocompromised, critically ill, long-term hospitalized and in those harboring invasive medical devices such as catheters. They have been implicated in infections such as urinary tract infections, bloodstream infections, and invasive device-related infections, and are responsible for substantial economic losses in livestock production. The advancement of diagnostic techniques has increased our understanding of their molecular mechanisms of pathogenicity, even though distinguishing between innocuousness and pathogenicity is still challenging. The incidence of CoNS varied across the continent in humans and animals (mainly cattle), ranging from 6% to 68% in suspected human infections and from 3% to 61.7% in suspected animal infections, distributed across different geographic locations. Furthermore, there were varying antibiotic resistance patterns observed in CoNS isolates, with high methicillin resistance in some cases, leading to crossresistance against many antibiotics. Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus xylosus were most commonly reported in studies herein reviewed, while the enterotoxin C gene, atl E gene, ica gene, and hemolysin virulence factors were linked with enhanced pathogenicity. Advancement in identification and typing methods, including whole genome sequencing, virulence screening, and the assessment of the immune status of subjects in studies will help to thoroughly assess the true pathogenic potential of isolated CoNS species in developing countries. Careful antibiotic stewardship guidelines should be followed due to the ability of CoNS to develop multidrug resistance.

Small Molecular Contaminant and Microorganism Can Be Simultaneously Detected Based on Nanobody-Phage: Using Carcinogen Aflatoxin and Its Main Fungal Aspergillus Section Flavi spp. in Stored Maize for Demonstration

Simultaneous detection technology has become a hot topic in analytical chemistry; however, very few reports on how to simultaneously detect small molecular contaminants and microorganisms have been in place. Aflatoxins are a group of highly toxic and carcinogenic compounds, which are produced mainly by Aspergillus flavus and Aspergillus parasiticus from section Flavi responsible for aflatoxin accumulation in stored cereals. Both aflatoxins and Aspergillus section Flavi were used to demonstrate the duplex real-time RCR method of simultaneously detecting small molecular contaminants and microorganisms. The detection of aflatoxins and Aspergillus section Flavi was carried out depending on the anti-idiotypic nanobody-phage V_2–5 and aflatoxin-synthesis related gene nor-1 (=aflD), respectively. The quantitative standard curves for simultaneous detection of aflatoxins and Aspergillus section Flavi were constructed, with detection limits of 0.02 ng/ml and 8 × 10² spores/g, respectively. Naturally contaminated maize samples (n = 25) were analyzed for a further validation. The results were in good agreement between the new developed method and the referential methods (high-performance liquid chromatography and the conventional plating counts).

Prevalence and antibiotic resistance of Acinetobacter baumannii among patients in postcardiac surgery intensive care units of Rajaei Hospital, Tehran

Background: Acinetobacter baumannii is an opportunistic, aerobic, nonfermentative, Gram-negative bacterium that can cause major nosocomial infections, especially in patients hospitalized in intensive care units (ICU). Recently, A. baumannii strains have been resistant to a variety of antibiotics. Thus, it was aimed to evaluate the prevalence of A. baumannii and their resistance to the antibiotics in the patients hospitalized in postcardiac surgery ICU. Methods: This retrospective cross sectional study was performed in Rajaei hospital between March 2014 and February 2016. A. baumannii strains were isolated from blood cultures, catheter cultures, sputum cultures, and wound smear cultures. Then, isolates were characterized using standard morphological, cultural, and biochemical properties according to CLSI 2016. The frequency of A. baumannii species were reported as percent. Results: Among 27 167 patients were admitted to the ICU, 113 individuals, including 55 males and 58 females, were identified as A. baumannii-infected and the prevalence rate was 0.42%. The highest rates of antibiotic sensitivity were related to Meropenem 20 (17.7%) and Colistin 16 (14.1%). The shortest length of stay (LOS) for patients with A. baumanniiin the ICU was 3 days, while the longest LOS was 98 days. Conclusion: The findings indicated that A. baumannii strains isolated from postcardiac surgery ICUs had a high prevalence and were sensitive to Meropenem and Colistin. However, new molecular-based techniques are needed to monitor nosocomial infections. Therefore, the treatment of the patients may be feasible by appropriate antibiotic therapy, and infection control policies will be improved by adopting precise disinfection strategies.

Riley L. Risk factors for fecal carriage of drug-resistant Escherichia coli: a systematic review and meta-analysis

BACKGROUND

Antimicrobial resistance is a serious public health problem. Fecal carriage of drug-resistant bacteria has been suggested as an important source of antimicrobial resistant genes (ARGs). We aimed to identify risk factors associated with fecal carriage of drug-resistant commensal Escherichia coli among healthy adult population.

METHODS

We conducted a systematic review and meta-analysis following the PRISMA guideline. We identified observational studies published from 2014 to 2019 through PubMed, Embase, and Web of Science. Studies were eligible if they investigated and reported risk factors and accompanying measure of associations for fecal carriage of drug-resistant E. coli for healthy population aged 18-65. Data on risk factors assessed in three or more studies were extracted.

RESULTS

Fifteen of 395 studies involving 11480 healthy individuals were included. The pooled prevalence of drug-resistant Enterobacteriaceae was 14% (95% confidence interval [CI] 8-23%). Antimicrobial use within the 12 months prior to stool culture (odds ratio [OR] 1.84 [95%CI 1.35-2.51]), diarrhea symptoms (OR 1.56 [95%CI 1.09-2.25]), travel to India (OR 4.15 [95%CI 2.54-6.78]), and vegetarian diet (OR 1.60 [95%CI 1.00(1.0043)-2.56(2.5587)]) were associated with increased risk of fecal carriage of drug-resistant E. coli. Among travellers, antimicrobial use (OR 2.81 [95%CI 1.47-5.36]), diarrhea symptoms (OR 1.65 [95%CI 1.02-2.68]), travel to India (OR 3.80 [95%CI 2.23-6.47]), and vegetarian diet (OR 1.92 [95%CI 1.13-3.26]) were associated with increased risk. Among general adult population, antimicrobial use (OR 1.51 [95%CI 1.17-1.94]), diarrhea symptoms (OR 1.53 [95%CI 1.27-1.84]), and travel to Southeast Asia (OR 1.67 [95%CI 1.02-2.73]) were associated with the increased risk of drug-resistant E. coli carriage.

CONCLUSIONS

The findings indicate that dietary habit as well as past antimicrobial use and travel to high-risk country are associated with the risk of fecal carriage of drug-resistant commensal E. coli.

Skin and soft tissue infection by Mycobacterium intracellulare in an immunocompetent patient

Nontuberculous mycobacteria (NTM) infections still represent a large group of insidious diseases hard to deal with. Traditionally, immunocompromised patients suffer from NTM infections, especially with respiratory involvement or disseminated diseases due to MAC (Mycobacterium avium complex). Here we report a rare case of Mycobacterium intracellulare infection involving skin and soft tissue, manifested as a chronic cutaneous ulcer in an immunocompetent patient with several comorbidities, including seizures. Accurate diagnosis of species was obtained with in vitro culture and RT-PCR (Real Time-Polymerase Chain Reaction) following a high clinical suspicion. Despite the high complexity of NTM infections, it is possible to achieve diagnostic goals through the appropriate employment of recent DNA-molecular technologies and an adequate management.

New Reusable Solid Biosensor with Covalent Immobilization of the Horseradish Peroxidase Enzyme: In Situ Liberation Studies of Hydrogen Peroxide by Portable Chemiluminescent Determination

Herein, we reported a chemiluminescent biosensor based on the covalent immobilization of the horseradish peroxidase (HRP) enzyme on a polydimethylsiloxane (PDMS) support to quantify in situ hydrogen peroxide (H₂O₂). The chemiluminescent reaction based on the use of luminol as an oxidizable substrate, with HRP as the catalyst, has been used in order to quantify H₂O₂ as the oxidizing agent. The performance of the proposed biosensor has been demonstrated to determine H₂O₂ liberated by cells in a culture medium and for evaluating the delivery of H₂O₂ from denture cleaner tablets, as examples of application. For both analyses, the results indicated that the biosensor is cost-effective, sensitive, and selective with a detection limit of 0.02 μM and good linearity over the range 0.06-10 μM. Precision was also satisfactory (relative standard deviation, % RSD < 6). The strength of this biosensing system is the simplicity, portability, and reusability of the devices; it can be applied up to 60 times with 90% of its activity maintained.

Alteration of Fungal Microbiota After 5-ASA Treatment in UC Patients

The effect of treatment regimens on fungal microbiota is unclear in ulcerative colitis (UC) patients. Here, we aimed to clarify the effect of 5-aminosalicylic acid (5-ASA) treatment on gut fungal microbiota in UC patients. Fifty-seven UC patients, including 20 treatment-naïve and 37 5-ASA-treated, were recruited into an exploration study. We compared the gut fungal profiles of these 2 groups of patients using ITS1-2 rDNA sequencing. Ten out of 20 treatment-naïve UC patients were followed up and enrolled for a validation study and underwent a 5-ASA treatment. We assessed the longitudinal differences of fungal microbiota in these patients before and after 5-ASA treatment. Results acquired from the validation study were accordant to those from the exploration study. Ascomycota was the dominant phylum in both noninflamed and inflamed mucosae. At the phylum level, Ascomycota decreased in inflamed mucosae before 5-ASA treatment. At the genus level, pathogens such as Scytalidium, Morchella, and Paecilomyces increased, and Humicola and Wickerhamomyces decreased in inflamed mucosae. After 5-ASA treatment, Ascomycota and Wickerhamomyces increased and Scytalidium, Fusarium, Morchella, and Paecilomyces decreased in both noninflamed and inflamed mucosae. Additionally, the balanced bacteria-fungi correlation was interrupted in inflamed mucosae, and 5-ASA treatment altered group-specific fungal microbiota and restored bacteria-fungi correlation in UC patients. Our results demonstrated that fungal diversity and composition were altered and the bacteria-fungi correlation was restored in inflamed mucosae after 5-ASA treatment.

Clinical features and endemic trend of histoplasmosis in China: A retrospective analysis and literature review

INTRODUCTION

Histoplasmosis is a rare mycosis with nonspecific clinical manifestation and a high misdiagnosis rate, which is an epidemic disease that occurred in several endemic areas. Cases of histoplasmosis were sporadic in China.

OBJECTIVE

We detected the clinical characteristics and endemic trend of histoplasmosis to understand it more profoundly.

METHOD

The clinical data of 34 cases of histoplasmosis hospitalized in Xiangya Hospital of Central South University from 2003 to 2016 were analyzed retrospectively. The relevant literature were reviewed roundly which were about histoplasmosis from 2001 to 2019 reported in the Chinese mainland.

RESULTS

Thirty-four patients were included in the study, male predominance. About 44.1% were combined with underlying disease and HIV infection was observed in eight patients. Common clinical manifestations were fever (94.1%), followed by lymphadenopathy (70.6%) and anemia (67.6%). Organ involvement included lungs (52.9%), oral cavity (5.9%) and intestine (5.9%). Patients were diagnosed by bone marrow smears (44.1%), lymph node biopsy (41.1%), lung tissue biopsy (8.8%) and intestinal tissue biopsy (5.9%). About 70.6% received amphotericin B, while 38.2% received itraconazole therapy and 79.4% were improved. About 611 cases of histoplasmosis in the Chinese mainland were obtained in the study from the related literature, with 217 (37.0%) cases occurred in Yunnan province, 69 (11.9%) cases in Hunan province and 67 (11.6%) cases in Hubei province. All of them were high incidence area of histoplasmosis.

CONCLUSION

Histoplasmosis is a rare mycosis with high diagnosis rate and has a prominent geographical distribution in China, which should be considered highly in clinical work.

Evaluation of cell-penetrating peptide-peptide nucleic acid effect in the inhibition of cagA in Helicobacter pylori

Helicobacter pylori is the most common cause of chronic infection in human and is associated with gastritis, peptic ulcer disease, and adenocarcinoma of mucosa-associated lymphoid tissue cells. Peptide nucleic acid (PNA) is a synthetic compound, which can inhibit the production of a particular gene. This study aimed to investigate the effect of PNA on inhibiting the expression of cagA. After confirmation of the desired gene by polymerase chain reaction (PCR), the antisense sequence was designed against cagA gene. The minimum inhibitory concentrations of conjugated PNA against H. pylori was determined. The effect of the compound on the expression level of the cagA was investigated in HT29 cell culture using real-time PCR. The results showed 2 and 3 log reduction in bacterial count after 8- and 24-h treatment with 4 and 8 μM of the compound, respectively. The lowest expression level of the cagA gene was observed at a concentration of 8 μM after 6 h. The results of this study showed that cell-penetrating peptide antisense can be employed as effective tools for inhibiting the target gene mRNA for various purposes. Moreover, further research is necessary to assess the potency, safety, and pharmacokinetics of CPP-PNAs for clinical prevention and treatment of infections due to H. pylori.

Bacterial dominance is due to effective utilisation of secondary metabolites produced by competitors

Interactions between bacteria govern the progression of respiratory infections; however, the mechanisms underpinning these interactions are still unclear. Understanding how a bacterial species comes to dominate infectious communities associated with respiratory infections has direct relevance to treatment. In this study, Burkholderia, Pseudomonas, and Staphylococcus species were isolated from the sputum of an individual with Cystic Fibrosis and assembled in a fully factorial design to create simple microcosms. Measurements of growth and habitat modification were recorded over time, the later using proton Nuclear Magnetic Resonance spectra. The results showed interactions between the bacteria became increasingly neutral over time. Concurrently, the bacteria significantly altered their ability to modify the environment, with Pseudomonas able to utilise secondary metabolites produced by the other two isolates, whereas the reverse was not observed. This study indicates the importance of including data about the habitat modification of a community, to better elucidate the mechanisms of bacterial interactions.

Orchestration of human macrophage NLRP3 inflammasome activation by Staphylococcus aureus extracellular vesicles

Release of extracellular vesicles (EVs) is a common feature among eukaryotes, archaea, and bacteria. However, the biogenesis and downstream biological effects of EVs released from gram-positive bacteria remain poorly characterized. Here, we report that EVs purified from a community-associated methicillin-resistant Staphylococcus aureus strain were internalized into human macrophages in vitro and that this process was blocked by inhibition of the dynamin-dependent endocytic pathway. Human macrophages responded to S. aureus EVs by TLR2 signaling and activation of NLRP3 inflammasomes through K+ efflux, leading to the recruitment of ASC and activation of caspase-1. Cleavage of pro-interleukin (IL)-1β, pro-IL-18, and gasdermin-D by activated caspase-1 resulted in the cellular release of the mature cytokines IL-1β and IL-18 and induction of pyroptosis. Consistent with this result, a dose-dependent cytokine response was detected in the extracellular fluids of mice challenged intraperitoneally with S. aureus EVs. Pore-forming toxins associated with S. aureus EVs were critical for NLRP3-dependent caspase-1 activation of human macrophages, but not for TLR2 signaling. In contrast, EV-associated lipoproteins not only mediated TLR2 signaling to initiate the priming step of NLRP3 activation but also modulated EV biogenesis and the toxin content of EVs, resulting in alterations in IL-1β, IL-18, and caspase-1 activity. Collectively, our study describes mechanisms by which S. aureus EVs induce inflammasome activation and reveals an unexpected role of staphylococcal lipoproteins in EV biogenesis. EVs may serve as a novel secretory pathway for S. aureus to transport protected cargo in a concentrated form to host cells during infections to modulate cellular functions.

Selective endpoint visualized detection of Vibrio parahaemolyticus with CRISPR/Cas12a assisted PCR using thermal cycler for on-site application

Vibrio parahaemolyticus is a major cause of seafood-associated food poisoning. It is of great significance to develop an accurate, simple and cost-effective method to identify infected seafood, especially for on-site application. Polymerase chain reaction (PCR) remains the golden standard for nucleic acid detection. But traditional methods heavily reply on sophisticated instrument and specialized operators, which limits the application for on-site detections. Here we developed a novel, specific and visualized detection method for PCR based on CRISPR/Cas12a system. On a low-cost thermal cycler, amplification reaction can be conducted easily. The CRISPR/Cas12a system was specifically designed to evaluate amplicons, eliminating false positive results. Besides the negative samples remained colorless, the positive samples generated obvious green fluorescence, which could be easily distinguished by the naked eye using a homemade UV device. The presented detection method was verified by detecting shrimp samples. The limit of detection is 1.02 × 10² copies/μL. This presented method provided a new strategy for specific endpoint detection of PCR and advanced its application in field for food safety assurance.

Deciphering the role of the capsule of Klebsiella pneumoniae during pathogenesis: A cautionary tale

Extracellular capsule polysaccharides increase the cellular fitness under abiotic stresses and during competition with other bacteria. They are best-known for their role in virulence, particularly in human hosts. Specifically, capsules facilitate tissue invasion by enhancing bacterial evasion from phagocytosis and protect cells from biocidal molecules. Klebsiella pneumoniae is a worrisome nosocomial pathogen with few known virulence factors, but the most important one is its capsule. In this issue, Tan et al. assess the fitness advantage of the capsule by competing a wild-type strain against four different mutants where capsule production is interrupted at different stages of the biosynthetic pathway. Strikingly, not all mutants provide a fitness advantage. They suggest that some mutants have secondary defects altering virulence-associated phenotypes and blurring the role of the capsule in pathogenesis. This study indicates that the K1 capsule in K. pneumoniae is not required for gut colonization but that it is critical for bloodstream dissemination to other organs. These results contribute to clarify the contradictory literature on the role of the Klebsiella capsule during infection. Finally, the varying fitness effects of different capsule mutations observed for K. pneumoniae K1 might apply also to other capsulated diderm bacteria that are facultative or emerging pathogens.

Methods of Granulocyte Isolation from Human Blood and Labeling with Multimodal Superparamagnetic Iron Oxide Nanoparticles

This in vitro study aimed to find the best method of granulocyte isolation for subsequent labeling with multimodal nanoparticles (magnetic and fluorescent properties) to enable detection by optical and magnetic resonance imaging (MRI) techniques. The granulocytes were obtained from venous blood samples from 12 healthy volunteers. To achieve high purity and yield, four different methods of granulocyte isolation were evaluated. The isolated granulocytes were labeled with multimodal superparamagnetic iron oxide nanoparticles (M-SPIONs) coated with dextran, and the iron load was evaluated qualitatively and quantitatively by MRI, near-infrared fluorescence (NIRF) and inductively coupled plasma mass spectrometry (ICP-MS). The best method of granulocyte isolation was Percoll with Ficoll, which showed 95.92% purity and 94% viability. After labeling with M-SPIONs, the granulocytes showed 98.0% purity with a yield of 3.5 × 10⁶ cells/mL and more than 98.6% viability. The iron-loading value in the labeled granulocytes, as obtained by MRI, was 6.40 ± 0.18 pg/cell. Similar values were found with the ICP-MS and NIRF imaging techniques. Therefore, our study shows that it is possible to isolate granulocytes with high purity and yield and labeling with M-SPIONs provides a high internalized iron load and low toxicity to cells. Therefore, these M-SPION-labeled granulocytes could be a promising candidate for future use in inflammation/infection detection by optical and MRI techniques.

Retrospective Screening and Analysis of mcr-1 and bla NDM in Gram-Negative Bacteria in China, 2010-2019

Currently, Gram-negative bacteria have developed multidrug and broad-spectrum drug resistance, and the numbers of species and strains carrying mcr or bla_NDM genes are increasing. In this study, mcr-1 and bla_NDM distribution of 12,858 Gram-negative bacteria isolated from wildlife, patients, livestock, poultry and environment in 14 provinces of China from 2010 to 2019 and the antibiotics resistance in regard to polymyxins (polymyxin B and colistin) and carbapenems of positive strains were investigated. A total of 70 strains of 10 species carried the mcr-1 gene, positive rates of patients, livestock and poultry, and environmental strains were 0.62% (36/5,828), 4.07% (29/712), 5.43% (5/92), respectively. Six strains of 3 species carrying the bla_NDM gene all came from patients 0.10% (6/5,828). Two new mcr-1 gene variants (GenBank: MK965883, MK965884) were identified, one of which contains premature stop codon. The drug susceptibility results showed that all mcr-1 carriers were sensitive to carbapenems, among which, 66 strains were resistant and 4 were sensitive to polymyxins. The strains with the bla_NDM gene had different degrees of resistance to carbapenems and were sensitive to polymyxins. The findings that species carrying mcr-1 or bla_NDM genes were limited and mostly normal flora of opportunistic or low pathogenic organisms indicated that transfer of mcr-1 and bla_NDM genes between bacteria was relatively limited in China. The none detection among wildlife compared with other sources supports the speculation that the emergence of and increase in polymyxins and carbapenem-resistant strains was mainly related to the selective pressure of antibiotics.

Recombinant infectious bronchitis coronavirus H120 with the spike protein S1 gene of the nephropathogenic IBYZ strain remains attenuated but induces protective immunity

Infectious bronchitis (IB) is a highly infectious viral disease responsible for major economic losses in the poultry industry. A reverse genetic vaccine is a safe, rapid, and effective method of achieving IB prevention and control. In this study, we constructed the recombinant strain, rH120-S1/YZ, using a reverse genetic system, based on the backbone of the H120 vaccine strain, with the S1 gene replaced with that of the QX-like nephropathogenic strain, ck/CH/IBYZ/2011, isolated in China. The results of dwarf chicken embryos, growth kinetics, and viral titration in the embryos demonstrated that the biological characteristics of the recombinant virus remained unchanged. Like the rH120-infected group and in contrast to the rIBYZ-infected group, no mortality, clinical signs, or lesions were observed in the lungs or kidneys of young chickens inoculated with rH120-S1/YZ. The viral loads in various tissues, cloacal, and oral swabs was lower in most types of samples, indicating that the rH120-S1/YZ strain was highly safe in chicks. Compared to rH120 vaccination group, when the efficacy of this strain was evaluated against the QX-like IBV strain, better protection, with 100% survival rate and no disease symptom or gross lesion was observed in the chickens vaccinated with rH120-S1/YZ. Increased levels of IBV-specific antibodies were detected in the serum of the rH120-S1/YZ-vaccinated animals 14 days post-vaccination. Collectively, our results suggest that the recombinant strain, rH120-S1/YZ, may represent a promising vaccine candidate against QX-like IBVs.

Bloodstream infections in critically ill patients: an expert statement

Bloodstream infection (BSI) is defined by positive blood cultures in a patient with systemic signs of infection and may be either secondary to a documented source or primary—that is, without identified origin. Community-acquired BSIs in immunocompetent adults usually involve drug-susceptible bacteria, while healthcare-associated BSIs are frequently due to multidrug-resistant (MDR) strains. Early adequate antimicrobial therapy is a key to improve patient outcomes, especially in those with criteria for sepsis or septic shock, and should be based on guidelines and direct examination of available samples. Local epidemiology, suspected source, immune status, previous antimicrobial exposure, and documented colonization with MDR bacteria must be considered for the choice of first-line antimicrobials in healthcare-associated and hospital-acquired BSIs. Early genotypic or phenotypic tests are now available for bacterial identification and early detection of resistance mechanisms and may help, though their clinical impact warrants further investigations. Initial antimicrobial dosing should take into account the pharmacokinetic alterations commonly observed in ICU patients, with a loading dose in case of sepsis or septic shock. Initial antimicrobial combination attempting to increase the antimicrobial spectrum should be discussed when MDR bacteria are suspected and/or in the most severely ill patients. Source identification and control should be performed as soon as the hemodynamic status is stabilized. De-escalation from a broad-spectrum to a narrow-spectrum antimicrobial may reduce antibiotic selection pressure without negative impact on mortality. The duration of therapy is usually 5–8 days though longer durations may be discussed depending on the underlying illness and the source of infection. This narrative review covers the epidemiology, diagnostic workflow and therapeutic aspects of BSI in ICU patients and proposed up-to-date expert statements.

Development of genome-wide polymorphic microsatellite markers for Trichinella spiralis

Background

Trichinella nematodes are globally distributed food-borne pathogens, in which Trichinella spiralis is the most common species in China. Microsatellites are a powerful tool in population genetics and phylogeographic analysis. However, only a few microsatellite markers were reported in T. spiralis. Thus, there is a need to develop and validate genome-wide microsatellite markers for T. spiralis.

Methods

Microsatellites were selected from shotgun genomic sequences using MIcroSAtellite identification tool (MISA). The identified markers were validated in 12 isolates of T. spiralis in China.

Results

A total of 93,140 microsatellites were identified by MISA from 9267 contigs in T. spiralis genome sequences, in which 16 polymorphic loci were selected for validation by PCR with single larvae from 12 isolates of T. spiralis in China. There were 7–19 alleles per locus (average 11.25 alleles per locus). The observed heterozygosity (H_O) and expected heterozygosity (H_E) ranged from 0.325 to 0.750 and 0.737 to 0.918, respectively. The polymorphism information content (PIC) ranged from 0.719 to 0.978 (average 0.826). Among the 16 loci, markers for 10 loci could be amplified from all 12 international standard strains of Trichinella spp.

Conclusions

Sixteen highly polymorphic markers were selected and validated for T. spiralis. Primary phylogenetic analysis showed that these markers might serve as a useful tool for genetic studies of Trichinella parasites.

Efflux pump inhibition controls growth and enhances antifungal susceptibility of Fusarium solani species complex

Aim: To evaluate the inhibition of efflux pumps by using promethazine (PMZ) as a strategy to control Fusarium solani species complex (FSSC). Materials & methods: The susceptibility of FSSC strains to PMZ and the interaction between PMZ and antifungals were evaluated. The efflux pump activity was confirmed by flow cytometry with rhodamine 6G. Finally, PMZ was tested against FSSC biofilms. Results: PMZ inhibited FSSC planktonic growth and showed synergism with antifungals. PMZ reduced R6G efflux and inhibited cell adhesion, impaired the development of biofilms and disrupted mature biofilms. PMZ-challenged biofilms showed increased sensitivity to amphotericin B. Conclusion: The study provides indirect evidence of the occurrence of efflux pumps in FSSC and opens a perspective for this target in the control of fusariosis.

Encephalitic Alphaviruses Exploit Caveola-Mediated Transcytosis at the Blood-Brain Barrier for Central Nervous System Entry

Venezuelan and western equine encephalitis viruses (VEEV and WEEV, respectively) invade the central nervous system (CNS) early during infection, via neuronal and hematogenous routes. While viral replication mediates host shutoff, including expression of type I interferons (IFN), few studies have addressed how alphaviruses gain access to the CNS during established infection or the mechanisms of viral crossing at the blood-brain barrier (BBB). Here, we show that hematogenous dissemination of VEEV and WEEV into the CNS occurs via caveolin-1 (Cav-1)-mediated transcytosis (Cav-MT) across an intact BBB, which is impeded by IFN and inhibitors of RhoA GTPase. Use of reporter and nonreplicative strains also demonstrates that IFN signaling mediates viral restriction within cells comprising the neurovascular unit (NVU), differentially rendering brain endothelial cells, pericytes, and astrocytes permissive to viral replication. Transmission and immunoelectron microscopy revealed early events in virus internalization and Cav-1 association within brain endothelial cells. Cav-1-deficient mice exhibit diminished CNS VEEV and WEEV titers during early infection, whereas viral burdens in peripheral tissues remained unchanged. Our findings show that alphaviruses exploit Cav-MT to enter the CNS and that IFN differentially restricts this process at the BBB.IMPORTANCE VEEV, WEEV, and eastern equine encephalitis virus (EEEV) are emerging infectious diseases in the Americas, and they have caused several major outbreaks in the human and horse population during the past few decades. Shortly after infection, these viruses can infect the CNS, resulting in severe long-term neurological deficits or death. Neuroinvasion has been associated with virus entry into the CNS directly from the bloodstream; however, the underlying molecular mechanisms have remained largely unknown. Here, we demonstrate that following peripheral infection alphavirus augments vesicular formation/trafficking at the BBB and utilizes Cav-MT to cross an intact BBB, a process regulated by activators of Rho GTPases within brain endothelium. In vivo examination of early viral entry in Cav-1-deficient mice revealed significantly lower viral burdens in the brain than in similarly infected wild-type animals. These studies identify a potentially targetable pathway to limit neuroinvasion by alphaviruses.

Antiviral activities of Radix isatidis polysaccharide against pseudorabies virus in swine testicle cells

Background

Radix isatidis has been used in China and other Asian countries for its antiviral and anti-inflammatory effects for thousands of years. However, the antiviral effect of Radix isatidis polysaccharide against pseudorabies virus (PRV) is still unknown.

Methods

The polysaccharide were isolated from extract of the roots of Radix isatidis. MTT assays were used to determine the preventive effect, inhibitory effect and antiviral effect of Radix isatidis polysaccharide on PRV in vitro.

Results

This study found that different concentrations of polysaccharides from this plant can inhibit PRV replication by 14.674–30.840%, prevent infection at rates of 6.668–14.923%, and kill this virus at rates of 32.214–67.422%.

Conclusion

These results broaden the understanding of this traditional Chinese herb and provide a theoretical basis for further research. Moreover, Radix isatidis polysaccharide could be used for antiviral therapy.

Integrative analysis of outer membrane vesicles proteomics and whole-cell transcriptome analysis of eravacycline induced Acinetobacter baumannii strains

BACKGROUND

Acinetobacter baumannii is a multidrug-resistant (MDR) hazardous bacterium with very high antimicrobial resistance profiles. Outer membrane vesicles (OMVs) help directly and/or indirectly towards antibiotic resistance in these organisms. The present study aims to look on the proteomic profile of OMV as well as on the bacterial transcriptome upon exposure and induction with eravacycline, a new synthetic fluorocycline. RNA sequencing analysis of whole-cell and LC-MS/MS proteomic profiling of OMV proteome abundance were done to identify the differential expression among the eravacycline-induced A. baumannii ATCC 19606 and A. baumannii clinical strain JU0126.

RESULTS

The differentially expressed genes from the RNA sequencing were analysed using R package and bioinformatics software and tools. Genes encoding drug efflux and membrane transport were upregulated among the DEGs from both ATCC 19606 and JU0126 strains. As evident with the induction of eravacycline resistance, ribosomal proteins were upregulated in both the strains in the transcriptome profiles and also resistance pumps, such as MFS, RND, MATE and ABC transporters. High expression of stress and survival proteins were predominant in the OMVs proteome with ribosomal proteins, chaperons, OMPs OmpA, Omp38 upregulated in ATCC 19606 strain and ribosomal proteins, toluene tolerance protein, siderophore receptor and peptidases in the JU0126 strain. The induction of resistance to eravacycline was supported by the presence of upregulation of ribosomal proteins, resistance-conferring factors and stress proteins in both the strains of A. baumannii ATCC 19606 and JU0126, with the whole-cell gene transcriptome towards both resistance and stress genes while the OMVs proteome enriched more with survival proteins.

CONCLUSION

The induction of resistance to eravacycline in the strains were evident with the increased expression of ribosomal and transcription related genes/proteins. Apart from this resistance-conferring efflux pumps, outer membrane proteins and stress-related proteins were also an essential part of the upregulated DEGs. However, the expression profiles of OMVs proteome in the study was independent with respect to the whole-cell RNA expression profiles with low to no correlation. This indicates the possible role of OMVs to be more of back-up additional protection to the existing bacterial cell defence during the antibacterial stress.

Flavonoids with antibacterial and antioxidant potentials from the stem bark of Uapaca heudelotti

Two flavonol glycosides; U1: naringenin-7-O-glucoside and U2: kaempferol-3-O-glucoside were isolated for the first time, from ethyl acetate fraction of the stem bark of a traditional medicinal plant called Uapaca heudelotti. IR and NMR spectroscopy were used to elucidate the structures of the isolated compound. The two compounds were active against the 7 tested microorganisms; Escherichia coli, Bacillus subtilis, Salmonella typhi, Streptococcus pyogenes, Klebsiella pneumoniae, Staphylococcus aureus and Proteus mirabilis. The zones of inhibition of the compounds ranged from 16 to 23 mm. The MIC value was as low as 6.25 μg/mL against Salmonella typhi, Streptococcus pyogenes, and Bacillus subtilis. The radical scavenging activity of compound U1 and U2 was 80 and 85 % at 240 μg/mL, while that of the standard drug was 98% at 240 μg/mL. The results show an existent possibility of using the plant for the treatment of microbial diseases.

Calcineurin A Is Essential in the Regulation of Asexual Development, Stress Responses and Pathogenesis in Talaromyces marneffei

Talaromyces marneffei is a common cause of infection in immunocompromised patients in Southeast Asia and Southern China. The pathogenicity of T. marneffei depends on the ability of the fungus to survive the cytotoxic processes of the host immune system and grow inside host macrophages. These mechanisms that allow T. marneffei to survive macrophage-induced death are poorly understood. In this study, we examined the role of a calcineurin homolog (cnaA) from T. marneffei during growth, morphogenesis and infection. Deletion of the cnaA gene in T. marneffei resulted in a strain with significant defects in conidiation, germination, morphogenesis, cell wall integrity, and resistance to various stressors. The ΔcnaA mutant showed a lower minimal inhibitory concentration (MIC) against caspofungin (16 μg/ml to 2 μg/ml) and micafungin (from 32 μg/ml to 4 μg/ml) compared with the wild-type. These results suggest that targeting calcineurin in combination with echinocandin treatment may be effective for life-threatening systemic T. marneffei infection. Importantly, the cnaA mutant was incapable of adapting to the macrophage environment in vitro and displayed virulence defects in a mouse model of invasive talaromycosis. For the first time, a role has been shown for cnaA in the morphology and pathogenicity of a dimorphic pathogenic filamentous fungus.

Potential Role of Cellular Senescence in Asthma

Cellular senescence is a complicated process featured by irreversible cell cycle arrest and senescence-associated secreted phenotype (SASP), resulting in accumulation of senescent cells, and low-grade inflammation. Cellular senescence not only occurs during the natural aging of normal cells, but also can be accelerated by various pathological factors. Cumulative studies have shown the role of cellular senescence in the pathogenesis of chronic lung diseases including chronic obstructive pulmonary diseases (COPD) and idiopathic pulmonary fibrosis (IPF) by promoting airway inflammation and airway remodeling. Recently, great interest has been raised in the involvement of cellular senescence in asthma. Limited but valuable data has indicated accelerating cellular senescence in asthma. This review will compile current findings regarding the underlying relationship between cellular senescence and asthma, mainly through discussing the potential mechanisms of cellular senescence in asthma, the impact of senescent cells on the pathobiology of asthma, and the efficiency and feasibility of using anti-aging therapies in asthmatic patients.

Antimicrobial mechanism of luteolin against Staphylococcus aureus and Listeria monocytogenes and its antibiofilm properties

Luteolin (LUT) is a naturally occurring compound found in a various of plants. Few recent studies have reported LUT antimicrobial activities against bacterial pathogens, however, the fundamental LUT mediated antimicrobial mechanism has never been elucidated. This study aimed to investigate the antimicrobial activities of LUT and its mode of action against Staphylococcus aureus and Listeria monocytogenes, either as planktonic cells or as biofilms. Here, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) of LUT against S. aureus and L. monocytogenes were determined using the broth microdilution method, and the antimicrobial mode of LUT was elucidated by evaluating the variations in both cell membrane integrity and cell morphology. Moreover, the biofilm inhibition was measured by crystal violet staining assay, while its qualitative imaging was achieved by confocal laser scanning microscope and field emission scanning electron microscope. MIC and MBC values of LUT against S. aureus were 16-32 and 32-64 μg/mL, and 32-64 and 64-128 μg/mL for L. monocytogenes. LUT destroyed the cell membrane integrity, as evidenced by a significant increase in the number of non-viable cells, and well-defined variations in cell morphology. Moreover, LUT presented robust inhibitory effects on the biofilm formation, enhanced antibiotics diffusion within biofilms and killed efficiently mono- and dual-species biofilm cells. Overall, LUT demonstrates potent antimicrobial properties on planktonic and biofilm cells, and the biofilm formation, and thus has the potential use as a natural food preservative in foods.

Coexistence of the blaNDM-1-carrying plasmid pWLK-NDM and the blaKPC-2-carrying plasmid pWLK-KPC in a Raoultella ornithinolytica isolate

To date, bla_NDM and bla_KPC genes have been found predominantly in clinical settings around the world. In contrast, bacteria harbouring these two genes from natural environments are relatively less well studied compared to those found in clinical settings. In this study, a carbapenem-resistant Raoultella ornithinolytica strain, WLK218, was isolated from urban river sediment in Zhengzhou City, Henan Province, China. This isolate was subjected to PCR and antimicrobial susceptibility testing. PCR results showed that this isolate was positive for both the bla_NDM-1 and bla_KPC-2 genes. The antimicrobial susceptibility testing results showed that this isolate exhibited resistance or intermediate resistance to all the antibiotics tested except for streptomycin (susceptible) and cefepime (susceptible-dose dependent). The complete genome sequence of the WLK218 isolate was then determined by using a combination of the PacBio and Illumina sequencing technologies. The de novo assembly of the genome generated one chromosome and six plasmids. Among the six plasmids, the bla_NDM-1 gene was carried on the IncX3 plasmid pWLK-NDM, while the bla_KPC-2 gene was located on the untypeable plasmid pWLK-KPC. This is the first report of an environmental Raoultella ornithinolytica isolate co-harbouring the bla_NDM-1 and bla_KPC-2 genes.

A novel vibriophage exhibits inhibitory activity against host protein synthesis machinery

Since the emergence of deadly pathogens and multidrug-resistant bacteria at an alarmingly increased rate, bacteriophages have been developed as a controlling bioagent to prevent the spread of pathogenic bacteria. One of these pathogens, disease-causing Vibrio parahaemolyticus (VPAHPND) which induces acute hepatopancreatic necrosis, is considered one of the deadliest shrimp pathogens, and has recently become resistant to various classes of antibiotics. Here, we discovered a novel vibriophage that specifically targets the vibrio host, VPAHPND. The vibriophage, designated Seahorse, was classified in the family Siphoviridae because of its icosahedral capsid surrounded by head fibers and a non-contractile long tail. Phage Seahorse was able to infect the host in a broad range of pH and temperatures, and it had a relatively short latent period (nearly 30 minutes) in which it produced progeny at 72 particles per cell at the end of its lytic cycle. Upon phage infection, the host nucleoid condensed and became toroidal, similar to the bacterial DNA morphology seen during tetracycline treatment, suggesting that phage Seahorse hijacked host biosynthesis pathways through protein translation. As phage Seahorse genome encodes 48 open reading frames with many hypothetical proteins, this genome could be a potential untapped resource for the discovery of phage-derived therapeutic proteins.

Molecular Characteristics of NDM-5-Producing Escherichia coli from a Cat and a Dog in South Korea

Carbapenemase-producing Enterobacteriaceae (CPE) have been very rarely reported in companion animals in South Korea. In this study, we aimed to investigate the molecular characteristics and relatedness of two New Delhi metallo-β-lactamase (NDM-5)-producing Escherichia coli isolates from rectal swabs of a dog and a cat hospitalized in different veterinary hospitals in South Korea during 2019. Antimicrobial susceptibility was tested by the Etest and broth microdilution method. PCR and sequencing were performed to detect antimicrobial resistance genes. Plasmid replicon typing and Southern blotting hybridization were performed to determine the replication origin of the plasmid and location of the bla_NDM-5 gene, respectively. Their macrorestriction profiles for E. coli isolates were assessed by multilocus sequence typing (MLST) and pulse-field gel electrophoresis (PFGE). The two carbapenem-resistant E. coli isolates harbored the bla_NDM-5 gene located on the IncX3 plasmid. Allele sequence analysis for MLST showed that the two E. coli isolates were attributed to sequence type 410 (ST410). The NDM-5-producing E. coli isolate from the cat presented high clonal similarity (94%) assessed by PFGE to a previously reported NDM-5-producing E. coli ST410 isolate from a dog hospitalized in the same hospital in 2017. The two E. coli isolates for the genetic environment surrounding the bla_NDM-5 gene had the same structure: ISAba125-bla_NDM-5-ble_MBL-trpF-TAT-ISCR26. This study revealed a direct transmission of the NDM-5-producing E. coli ST410 isolate between a dog and a cat. This is the first report of NDM-5 carbapenemase-producing E. coli isolate from a cat in South Korea.

A Moraxella Virulence Factor Catalyzes an Essential Esterase Reaction of Biotin Biosynthesis

Pimeloyl-acyl carrier protein (ACP) methyl ester esterase catalyzes the last biosynthetic step of the pimelate moiety of biotin, a key intermediate in biotin biosynthesis. The paradigm pimeloyl-ACP methyl ester esterase is the BioH protein of Escherichia coli that hydrolyses the ester bond of pimeloyl-ACP methyl ester. Biotin synthesis in E. coli also requires the function of the malonyl-ACP methyltransferase gene (bioC) to employ a methylation strategy to allow elongation of a temporarily disguised malonate moiety to a pimelate moiety by the fatty acid synthetic enzymes. However, bioinformatics analyses of the extant bacterial genomes showed that bioH is absent in many bioC-containing bacteria. The genome of the Gram-negative bacterium, Moraxella catarrhalis lacks a gene encoding a homolog of any of the six known pimeloyl-ACP methyl ester esterase isozymes suggesting that this organism encodes a novel pimeloyl-ACP methyl ester esterase isoform. We report that this is the case. The gene encoding the new isoform, called btsA, was isolated by complementation of an E. coli bioH deletion strain. The requirement of BtsA for the biotin biosynthesis in M. catarrhalis was confirmed by a biotin auxotrophic phenotype caused by deletion of btsA in vivo and a reconstituted in vitro desthiobiotin synthesis system. Purified BtsA was shown to cleave the physiological substrate pimeloyl-ACP methyl ester to pimeloyl-ACP by use of a Ser117-His254-Asp287 catalytic triad. The lack of sequence alignment with other isozymes together with phylogenetic analyses revealed BtsA as a new class of pimeloyl-ACP methyl ester esterase. The involvement of BtsA in M. catarrhalis virulence was confirmed by the defect of bacterial invasion to lung epithelial cells and survival within macrophages in the ΔbtsA strains. Identification of the new esterase gene btsA exclusive in Moraxella species that links biotin biosynthesis to bacterial virulence, can reveal a new valuable target for development of drugs against M. catarrhalis.

Campylobacter jejuni Strain Dynamics in a Raccoon (Procyon lotor) Population in Southern Ontario, Canada: High Prevalence and Rapid Subtype Turnover

Free-ranging wildlife are increasingly recognized as potential reservoirs of disease-causing Campylobacter species such as C. jejuni and C. coli. Raccoons (Procyon lotor), which live at the interface of rural, urban, and more natural environments, are ideal subjects for exploring the potential role that wildlife play in the epidemiology of campylobacteriosis. We studied the prevalence and genetic diversity of Campylobacter from live-captured raccoons on five swine farms and five conservation areas in southwest Ontario. From 2011 to 2013, we collected fecal swabs (n = 1,096) from raccoons, and (n = 50) manure pit samples from the swine farm environment. We subtyped the resulting Campylobacter isolates (n = 581) using Comparative Genomic Fingerprinting (CGF) and 114 distinct subtypes were observed, including 96 and 18 subtypes among raccoon and manure pit isolates, respectively. Campylobacter prevalence in raccoons was 46.3%, with 98.7% of isolates recovered identified as C. jejuni. Novel raccoon-specific CGF subtypes (n = 40/96) accounted for 24.6% (n = 143/581) of Campylobacter isolates collected in this study. Our results also show that C. jejuni is readily acquired and lost in this wild raccoon population and that a high Campylobacter prevalence is observed despite transient carriage typically lasting 30 days or fewer. Moreover, although raccoons appeared to be colonized by species-adapted subtypes, they also harbored agriculture-associated genotypes that accounted for the majority of isolates observed (66.4%) and that are strongly associated with human infections. This suggests that raccoons may act as vectors in the transmission of clinically-relevant C. jejuni subtypes at the interface of rural, urban, and more natural environments.

Prevalence of Extended-Spectrum β-lactamase and Integron Gene Carriage in Multidrug-Resistant Klebsiella Species Isolated from Outpatients in Yazd, Iran

Background:

Community-acquired infections by multidrug-resistant (MDR), extended-spectrum β-lactamase (ESBL) producing Klebsiella species (Klebsiella spp.) is of major concern worldwide. Antibiotic resistance, production of extended-spectrum β-lactamases (ESBLs), and carbapenemases, as well as the presence of classes 1, 2, and 3 integrons in outpatient isolates of Klebsiella collected from Yazd central laboratory, Yazd, Iran

Methods:

We collected 250 Klebsiella isolates from Yazd central laboratory between August 2015 and October 2017. Antibiotic susceptibility was determined against 18 antibiotics by disc diffusion, and multidrug-resistant isolates were tested for ESBL production by the phenotypic confirmatory test according to CLSI 2017 protocols. The amplification of β-lactamase genes bla_SHV, bla_TEM, bla_CTX-M, bla_OXA-48, bla_KPC, and bla_NDM, classes 1, 2, and 3 integrase genes, was carried out using specific primers and polymerase chain reaction (PCR)

Results:

Of the 250 Klebsiella outpatient isolates, 3.6% were K. oxytoca and the rest were K. pneumoniae. Disc diffusion showed that 21 (8.4%) isolates were MDR, 19 (90.4%) of which were ESBL producers including one K. oxytoca. The most prevalent β-lactamase gene was bla_SHV followed by bla_TEM and bla_CTX-M, but bla_OXA-48, bla_KPC, and bla_NDM were not detected. Class 1 integron was detected in 18 out of 21 MDR isolates (85.7%), but classes 2 and 3 were not observed. Two isolates were resistant to carbapenems and harbored bla_SHV, bla_TEM, and bla_CTX-M, as well as class 1 integron.

Conclusion:

ESBL production and the presence of multiple β-lactamase genes in MDR community isolates of Klebsiella spp. can have significant implications in terms of the spread of these opportunistic pathogens.

Carriage of Extended-Spectrum-β-Lactamase- and AmpC-β-Lactamase-Producing Enterobacteriaceae (ESBL-PE) in Healthy Community and Outpatient Department (OPD) Patients in Nepal

Background

Extended-spectrum β-lactamase (ESBL)- and AmpC-β-lactamase (ESBL)- and AmpC-Enterobacteriaceae have recently emerged as a public threat in the treatment of nosocomial as well as community-acquired infections. Very little information is currently available about its existence in Nepal. We, therefore, aim to determine the prevalence of ESBL and AmpC-β-lactamase (ESBL)- and AmpC-Enterobacteriaceae have recently emerged as a public threat in the treatment of nosocomial as well as community-acquired infections. Very little information is currently available about its existence in Nepal. We, therefore, aim to determine the prevalence of ESBL and AmpC-

Methods

During a 6-month period (November 2014–April 2015), a total of 190 stool specimens from 190 participants were obtained from different population. Of the total 260 fecal isolates, 152 from outpatient department (OPD) and 108 from healthy volunteer were collected. Stool specimens were cultured and enterobacterial isolates were subjected to antimicrobial susceptibility tests according to the standard microbiologic guidelines. ESBL was screened using ceftazidime (CAZ, 30 μg) and cefotaxime (CTX, 30 μg) and cefotaxime (CTX, 30 β-lactamase (ESBL)- and AmpC-

Results

The prevalence of ESBL, AmpC-β-lactamase (ESBL)- and AmpC-β-lactamase (ESBL)- and AmpC-Enterobacteriaceae have recently emerged as a public threat in the treatment of nosocomial as well as community-acquired infections. Very little information is currently available about its existence in Nepal. We, therefore, aim to determine the prevalence of ESBL and AmpC-E. coli was 70.2% followed by K. pneumoniae (12.7%), and among AmpC-β-lactamase (ESBL)- and AmpC-E. coli was 70.2% followed by E. coli was 70.2% followed by K. pneumoniae (12.7%), and among AmpC-K. pneumoniae (12.7%), and among AmpC-C. freundii 2/7 (28.57%) were detected highest among AmpC-β-lactamase (ESBL)- and AmpC-

Conclusion

Our study revealed a high prevalence of ESBL- and AmpC-β-lactamase-producing enteric pathogen in Nepalese OPD and healthy population. The significant increase of these isolates and increased rate of drug resistance indicates a serious threat that stress the need to implement the surveillance system and a proper control measure so as to limit the spread of ESBL-producing Enterobacteriaceae (ESBL-PE) in both OPD as well as in community. Therefore, healthcare providers need to be aware that ESBL- and AmpC-β-lactamase-producing strains are not only circulating in hospital environments but also in the community and should be dealt with accordingly.β-lactamase (ESBL)- and AmpC-Enterobacteriaceae have recently emerged as a public threat in the treatment of nosocomial as well as community-acquired infections. Very little information is currently available about its existence in Nepal. We, therefore, aim to determine the prevalence of ESBL and AmpC-β-lactamase (ESBL)- and AmpC-

Antimicrobial Activity of Host-Derived Lipids

Host-derived lipids are increasingly recognized as antimicrobial molecules that function in innate immune activities along with antimicrobial peptides. Sphingoid bases and fatty acids found on the skin, in saliva and other body fluids, and on all mucosal surfaces, including oral mucosa, exhibit antimicrobial activity against a variety of Gram positive and Gram negative bacteria, viruses, and fungi, and reduce inflammation in animal models. Multiple studies demonstrate that the antimicrobial activity of lipids is both specific and selective. There are indications that the site of action of antimicrobial fatty acids is the bacterial membrane, while the long-chain bases may inhibit cell wall synthesis as well as interacting with bacterial membranes. Research in this area, although still sporadic, has slowly increased in the last few decades; however, we still have much to learn about antimicrobial lipid mechanisms of activity and their potential use in novel drugs or topical treatments. One important potential benefit for the use of innate antimicrobial lipids (AMLs) as antimicrobial agents is the decreased likelihood side effects with treatment. Multiple studies report that endogenous AML treatments do not induce damage to cells or tissues, often decrease inflammation, and are active against biofilms. The present review summarizes the history of antimicrobial lipids from the skin surface, including both fatty acids and sphingoid bases, in multiple human body systems and summarizes their relative activity against various microorganisms. The range of antibacterial activities of lipids present at the skin surface and in saliva is presented. Some observations relevant to mechanisms of actions are discussed, but are largely still unknown. Multiple recent studies examine the therapeutic and prophylactic uses of AMLs. Although these lipids have been repeatedly demonstrated to act as innate effector molecules, they are not yet widely accepted as such. These compiled data further support fatty acid and sphingoid base inclusion as innate effector molecules.

Raising awareness about microbial antibiotic resistance in undergraduate dental students: a research-based strategy for teaching non-laboratory elements of a microbiology curriculum

BACKGROUND

Resistance to antimicrobial agents has become a problem in modern society. Antibiotic resistant bacteria undermine the prevention and treatment of infections. Undergraduate dental students in Europe are required to receive information in aspects of microbiology relevant for dental practice, including oral microbial pathogens and resistance mechanisms against antimicrobial compounds. The objective of this study was to implement a research-based strategy to aid the understanding of the increase in antimicrobial resistance in undergraduate dental student training. The primary outcome of this project is the efficacious delivery of the learning objectives.

METHODS

Ten volunteer undergraduate student "ambassadors" were recruited to manage the project with assistance from lead academics. Student ambassadors were a source of peer learning for their colleagues. The project consisted of three phases: Pre-project preparation (in which the ambassadors received special instruction and training); Practical experience (in which the ambassadors worked with volunteer student colleagues to carry out the project); Public presentation of results (in which ambassadors presented study results at a scientific conference of their choosing).

RESULTS

A total of 1164 students volunteered for the project, corresponding to an average participation rate of 76.4% students per year of the course. Following final debriefing, student participants and ambassadors were strongly positive in their evaluation of the achievement of 8 key student learning objectives. The results demonstrate that most volunteers improved their knowledge related to antimicrobial resistance mechanisms in microbiology. Additional benefits of participation in this project included an improvement in dental knowledge and ethics in biomedical research for the student volunteers, whilst the student ambassadors reported improved knowledge about critical thinking and study design, as well as a deeper understanding about microbiological analysis methods.

CONCLUSIONS

To the best of our knowledge, this the first instance of the application of project-based methodologies to the teaching of a traditionally non-laboratory component of a subject taught in the dentistry curriculum. Results from both students and ambassadors highlighted the increase in dental knowledge and an increased awareness of antimicrobial resistance as the key outcomes of this project.

Principios físicoquímicos de los colorantes utilizados en microbiología Principios físicoquímicos de los colorantes

La utilización de los colorantes en los procesos de identificación en microbiología se fundamenta en las propiedades fisicoquímicas de estas sustancias. En el campo de la física, la óptica explica cómo todos los objetos son observables dependiendo de las longitudes de onda que se absorben y se transmiten dentro del denominado “espectro visible”. Dichas transiciones se deben, a su vez, a los compuestos químicos y a los movimientos electrónicos dentro de los átomos. Así mismo, cuando interacciona un colorante con una célula o un tejido, ocurren reacciones que dependen de grupos químicos  funcionales denominados cromóforos y auxocromos. Dependiendo de los compuestos químicos que los constituyen, los colorantes pueden ser ácidos, básicos o neutros y esta connotación se debe a la parte activa del colorante y a la reacción que ocasiona sobre las células microbianas. De otra parte, las tinciones en microbiología pueden ser simples o diferenciales, dependiendo si toda la muestra se tiñe de uno o más colorantes. En el primer caso se encuentra el ejemplo de la coloración con azul de lactofenol y en el segundo, la coloración de Gram. En el presente artículo se reseñan las principales coloraciones utilizadas en microbiología y se explican los fundamentos físicos y químicos de dichos procesos.

Bacillus cereus: public health burden associated with ready-to-eat foods in Himachal Pradesh, India

The study determined incidence, enterotoxigenecity and antimicrobial susceptibility profiles of Bacillus cereus isolated from ready-to-eat (RTE) milk products (n = 80), RTE meat products (n = 40), beverages (n = 40) and water samples (n = 60, from food preparing and serving outlets/restaurants) collected from eight different tourist places of Himachal Pradesh. 11.4% (25/220) samples were contaminated with Bacillus and isolates were identified as B. cereus (76.0%, n = 19), B. alvei (12.0%, n = 3), B. polymyxa (8.0%, n = 2) and B. firmus (4.0%, n = 1) by conventional and molecular methods. B. cereus incidence was highest in cheese based foods (25.0%) followed by vegetable soups (16.7%), khoa based foods (14.0%), milk based beverages (10.5%), paneer based foods (8.6%), cream based foods (8.3%) and water (8.3%) samples. Multiplex polymerase chain reaction detected enterotoxigenic genes only in B. cereus isolates. nhe complex (encoding non-haemolytic enterotoxins, ABC) genes were detected only in B. cereus isolates. 57.6% (11/19), 36.8% (7/19) and 5.3% (1/19) harboured all three (nheA, nheB, nheC), two (nheB, nheC) and one (nheC) nhe gene, respectively. Among hbl complex genes (encoding haemolytic enterotoxins CAD), only hblC (36.8%, 7/19) was detected. Incidence B. cereus cytK (encoding cytotoxin enterotoxin) was 52.6% (10/19). Each B. cereus isolate harboured two or more enterotoxigenic genes. Seven isolates had at least one gene from haemolytic and non-haemolytic complexes along with cytK. High levels (> 50%) of antimicrobial resistance were recorded for penicillin, amoxicillin, ampicillin cefixime and ceftazidine in tested B. cereus isolates. Two isolates were identified as multidrug resistant isolates with resistance to ≥ 3 antibiotic classes.

Chinese medicinal herb extract inhibits PQS-mediated quorum sensing system in Pseudomonas aeruginosa

ETHNOPHARMACOLOGICAL RELEVANCE

Chinese medicinal herbs have long been recognized as important resources that can be used for the struggle against diseases and a significant component of health care system for thousands of years.

AIM OF THE STUDY

In order to understand their roles in the treatment against bacterial infections, we examined the underlying mechanisms of one of the medicinal herb extracts (MHE) (Artemisiae argyi Folium, the root bark of Cortex dictamni and the root of Solanum melongena) on the human opportunistic pathogen Pseudomonas aeruginosa.

MATERIALS AND METHODS

We combined phenotypic assays, transcriptional analysis and chemical investigations to identify the mechanisms underlying MHE inhibition. The standard sample was prepared and transcriptional reporters for quorum sensing systems were constructed. Electrophoretic mobility shift assays were used to clarify the mechanism. GC-MS and molecular docking were used to identify the chemicals in MHE and potential binding agents.

RESULTS

We found that co-culturing of MHE with bacterial cells did not change the growth rate but substantially attenuate the production of virulence factors such as phenazine pyocyanin, siderophore pyoverdine and biofilm formation. Transcriptional responses of three major quorum sensing (QS) systems of P. aeruginosa to MHE showed that Pseudomonas quinolone signaling (PQS) system was completely repressed, rhlR/rhlI QS system was moderately inhibited, while lasR/lasI QS system was only slightly affected, suggesting that MHE might selectively target the PQS system to inhibit bacterial virulence. Furthermore, electrophoretic mobility shift assays (EMSA) showed that MHE inhibited the binding of MvfR the corresponding pqsA promoter region, suggesting that MHE serves as a competitive agent to quench the QS functionality in P. aeruginosa.

CONCLUSION

We prove that MHE functions as an effective countermeasure against bacterial infections.

Toxocara-induced neural larva migrans (neurotoxocarosis) in rodent model hosts

Neural larva migrans (NLM), or neurotoxocarosis, induced by Toxocara canis or Toxocara cati results from migrating and persisting larvae in the central nervous system of paratenic hosts, including humans. As the diagnosis of NLM in humans is not straightforward, most knowledge on the disease is derived from only a few published clinical cases. To improve our understanding of human NLM, studies on the pathogenesis and clinical symptoms in laboratory animal model systems are indispensable, and rodents have been accepted as the most appropriate model organisms for NLM. As research has mostly focused on neuroinvasive T. canis-larvae, information regarding the pathogenesis of T. cati-induced NLM remains scarce. This review summarises the current state of knowledge on neuroinvasion by both T. canis and T. cati in different rodent model hosts, the resulting behavioural changes, and histopathological alterations during the course of NLM as well as the potential molecular pathogenic mechanisms.

Advances in patent applications related to cancer vaccine using CpG-ODN and OX40 association

Introduction: This review aims to assess the available technologies, advances, and trends from technological readiness level 4 to level 8 for cancer immunologic therapeutics using the association of OX40 and CPG-ODN, usually known as cancer vaccine.Areas covered: Patent documents and clinic studies referring to the use of CpG-ODN and of OX40 association for cancer therapeutics. Patent data were obtained within the worldwide basis of the European Patent Office (EPO). The 138 patents of 36 patent families found were analyzed focusing on word distribution of technology developers and potential markets, legal status, annual evolution of first priority, technological domains, applicants and co-applicants and detailed analysis of each technology. Two clinical studies are in progress.Expert opinion: Traditional methods in post cancer diagnosis are being replaced by immunological association therapies. It is expected that the development of cancer vaccines will expand the scope of cancer-specific immunotherapy, especially if associated with alternative systems for expression and delivery with future potential. It is expected that genetic and controlled and/or specific nano delivery are improved. Furthermore, these new developments will likely address the problem of long-term treatments, reducing cancer mortality and reducing patient numbers worldwide.

Chemically-Modified Curcumin 2.24: A Novel Systemic Therapy for Natural Periodontitis in Dogs

Purpose

To determine the effect of a pleiotropic MMP-inhibitor, a novel chemically-modified curcumin 2.24 (CMC2.24), on the clinical and biological measures of naturally-occurring periodontitis in the beagle dog.

Methods

Eight adult female dogs with generalized periodontitis were distributed into two groups: Placebo and Treatment (n=4/group). After a 1-hr full-mouth scaling and root planing (SRP) at time 0, placebo or CMC2.24 (10mg/kg) capsules were orally administered once/day for 3 months. Various clinical periodontal parameters (e.g., pocket depth, gingival index) were measured at different time periods (0, 1, 2 and 3 months), and gingival crevicular fluid (GCF) samples and gingival tissue biopsies (3-month) were analyzed for cytokines, MMPs and cell-signaling molecules. Standardized radiographs were taken at 0 and 3-month; in addition, peripheral blood monocytes/macrophages from these dogs at 3-month were cultured and analyzed for the pro-, activated-, and total-forms of both MMP-2 and MMP-9.

Results

CMC2.24 treatment significantly reduced gingival inflammation (gingival index, GCF flow), pocket depth (PD), and the numbers of pockets (PD≥4mm), compared to placebo. CMC2.24 also significantly reduced MMP-9 and MMP-2 (primarily in the activated-form) in gingival tissue, alveolar bone loss, and reduced GCF IL-1β. Cell-signaling molecules, TLR-2 (but not TLR-4) and p38 MAPK, responded to CMC2.24 in a pattern consistent with reductions in inflammation and collagenolysis. In culture, CMC2.24 had no effect on pro-MMP-9 but essentially completely blocked the conversion of pro- to activated-MMP-9 in systemic blood-derived monocytes/macrophages from these dogs.

Conclusion

In the beagle dog model of natural periodontitis, orally administered CMC2.24 (a novel triketonic phenylaminocarbonyl-curcumin) significantly decreased clinical measures of periodontitis as well as pro-inflammatory cytokines, MMPs, and cell-signaling molecules. These and previous studies, using other in vitro and in vivo models, support the clinical potential of CMC2.24 as a novel adjunct to SRP in the treatment of chronic periodontitis.

BMP Signaling in Development, Stem Cells, and Diseases of the Gastrointestinal Tract

The bone morphogenetic protein (BMP) pathway is essential for the morphogenesis of multiple organs in the digestive system. Abnormal BMP signaling has also been associated with disease initiation and progression in the gastrointestinal (GI) tract and associated organs. Recent studies using animal models, tissue organoids, and human pluripotent stem cells have significantly expanded our understanding of the roles played by BMPs in the development and homeostasis of GI organs. It is clear that BMP signaling regulates GI function and disease progression that involve stem/progenitor cells and inflammation in a tissue-specific manner. In this review we discuss these new findings with a focus on the esophagus, stomach, and intestine.

RM, Giraldo Quintero SE, Bernal Lizarazú MC. Actividad in vitro de los extractos etanólicos de Lantana camara L., Petiveria alliacea L. y Lippia dulcis T. frente a bacterias patógenas

Introducción. La biodiversidad colombiana y los saberes tradicionales permiten la exploración de plantas medicinales con potencial actividad antimicrobiana que podrían usarse para tratamiento de infecciones. Objetivos. Determinar la actividad antibacteriana de extractos etanólicos de Lantana camara L., Petiveria alliacea L. y Lippia dulcis T. sobre Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 25922, Proteus vulgaris ATCC 6380 y Staphylococcus aureus ATCC 25923. Materiales y métodos. Se realizó la adquisición del material vegetal y caracterización botánica, se obtuvieron los extractos etanólicos por percolación y se realizó caracterización fitoquímica preliminar mediante cromatografía en capa delgada (CCD). Se evaluó la actividad antibacteriana, mediante pruebas de difusión con disco y difusión en agar en concentraciones de 1mg/mL y 2mg/mL; para extractos activos se estableció la Concentración Inhibitoria mínima (CIM) y Concentración Mínima Bactericida (CMB). Para análisis estadístico se realizó prueba t de Student. Resultados y discusión. Staphylococcus aureus ATCC 25923 fue sensible con Lantana camara L. y Lippia dulcis T. siendo este último activo también sobre Proteus vulgaris ATCC 6380 con efecto inhibitorio superior al 50%. El extracto de Lippia dulcis T. presentó la mayor actividad inhibitoria sobre S. aureus (CMI: 1,95 mg/mL). Ningún extracto mostró actividad sobre Escherichia coli ni Pseudomonas aeruginosa. Metabolitos secundarios, especialmente terpenoides y cumarinas fueron detectados en L. dulcis. Conclusiones. El estudio muestra que productos naturales derivados de plantas medicinales como los extractos etanólicos de Lantana camara y Lippia dulcis, presentan actividad antibacteriana sobre S. aureus y P. vulgaris y podrían ser alternativa promisoria para tratamiento de infecciones bacterianas.

Eliminating primer dimers and improving SNP detection using self-avoiding molecular recognition systems

Despite its widespread value to molecular biology, the polymerase chain reaction (PCR) encounters modes that unproductively consume PCR resources and prevent clean signals, especially when high sensitivity, high SNP discrimination, and high multiplexing are sought. Here, we show how "self-avoiding molecular recognition systems" (SAMRS) manage such difficulties. SAMRS nucleobases pair with complementary nucleotides with strengths comparable to the A:T pair, but do not pair with other SAMRS nucleobases. This should allow primers holding SAMRS components to avoid primer-primer interactions, preventing primer dimers, allowing more sensitive SNP detection, and supporting higher levels of multiplex PCR. The experiments here examine the PCR performances of primers containing different numbers of SAMRS components placed strategically at different positions, and put these performances in the context of estimates of SAMRS:standard pairing strengths. The impact of these variables on primer dimer formation, the overall efficiency and sensitivity of SAMRS-based PCR, and the value of SAMRS primers when detecting single nucleotide polymorphisms (SNPs) are also evaluated. With appropriately chosen polymerases, SNP discrimination can be greater than the conventional allele-specific PCR, with the further benefit of avoiding primer dimer artifacts. General rules guiding the design of SAMRS-modified primers are offered to support medical research and clinical diagnostics products.

Evaluation of an electronic, patient-focused management system aimed at preventing cytomegalovirus disease following solid organ transplantation

BACKGROUND

Cytomegalovirus (CMV) infection is common among solid organ transplant (SOT) recipients and may cause CMV disease. To optimize the implementation of existing prevention strategies, the Management of Post-transplant Infections in Collaborating Hospitals (MATCH) program was developed. Two key performances of MATCH (diagnosing CMV infection at low viral load (VL) and before the onset of CMV disease) were assessed prior to, during and after the implementation of MATCH.

METHODS

The MATCH program included a personalized surveillance plan, prophylaxis and preemptive therapy determined by the recipient's risk of CMV infection. The plan was composed through predefined algorithms and implemented through harvesting of real-time data from medical records. Risk of CMV disease was compared for recipients transplanted during and after vs prior to the implementation of MATCH. Lung and non-lung transplants were analyzed separately.

RESULTS

A total of 593, 349, 520, and 360 SOT recipients were transplanted before (2007-2010), during (2011-2012), early after (2013-2015), and late after (2016-2017) implementation of MATCH with an observed reduction of diagnostic VL (P < .001) over time. Risk of CMV disease was reduced among non-lung transplant recipients transplanted during (adjusted hazard ratios [95% CI] 0.15 [0.04-0.54], P = .003), early after (aHR 0.27 [0.11-0.63], P = .003), and late after (aHR 0.17 [0.06-0.52], P = .002) compared with prior to MATCH. No significant change was observed among lung transplants.

CONCLUSION

Implementation of CMV preventive strategies through MATCH was associated with a reduced risk of CMV disease among non-lung transplant recipients. Furthermore, the limitations of VL as a sole indicator for CMV disease in lung transplants were emphasized.

Antibiotic resistance genes as landscape anthropization indicators: Using a wild felid as sentinel in Chile

Antimicrobial resistance is a global emerging public health issue whose presence and impact in wildlife are widely unknown. Antimicrobial resistance genes (ARGs) are considered environmental contaminants, suitable to evaluate the degree of anthropic impact on wildlife and the environment. We used a wild felid, the guigna (Leopardus guigna), as a sentinel for the presence of ARGs in anthropized and pristine areas across their entire distribution range in Chile. We evaluated fecal samples from 51 wild guignas, collected between 2009 and 2018. Real-time PCR essays were employed to detect and quantify 22 selected ARGs in their fecal microbiome. All animals (100%) were positive for at least one ARG. The most prevalent ARG families were those that confer resistance to tetracycline (88.2%) and beta-lactamase (68.9%), with tet(Q) (60.8%), tet(W) (60.8%), and bla_TEM (66.7%) as the most prevalent ARGs. Multi-resistance profiles were observed in 43% of the guignas. Statistically significant differences were found between anthropized and pristine areas for tet(Q) (p = 0.014), tet(W) (p = 0.0037), tetracycline family (p = 0.027), multi-resistance profile prevalence (p = 0.043) and tet(W) quantification (p = 0.004). Two animals from anthropized landscapes were positive for mecA, a gene associated with Staphylococcus aureus and other staphylococci resistant to methicillin, while three animals from anthropized areas were positive for bla_CTX-M, that encodes class A extended-spectrum beta-lactamase. Both genes have been identified in bacteria causing relevant nosocomial infections worldwide. This is the first study on ARGs in wild felids from Chile and the first detection of mecA in South American wild felids. We observed an association between the degree of landscape anthropization and ARG prevalence, confirming that ARGs are important indicators of wildlife exposure to human activity/presence, with a widespread distribution.

Hyperbaric oxygen treatment: A complementary treatment modality of Modic changes?

Modic changes (MCs) have attracted great interest in recent years. The complex process of MC development and progression seems to involve interplay between mechanical, infective, inflammatory, and degenerative processes that cannot be clearly differentiated. Based on signal intensity on T1- and T2-weighted MRI scans, MCs can be divided three types: Type 1, Type 2, and Type 3. Predominantly Type 1 MCs are commonly associated with chronic low back pain that is unresponsive to classic treatment options. Infection with low-virulent anaerobic microorganisms, most commonly Propionibacterium acnes, has been implicated in MC development following a disc herniation when a tear enables bacteria to enter the disc. Recent studies in patients with chronic low back pain following a lumbar disc herniation associated with Type 1 MCs have reported promising results following prolonged systemic antibiotic treatment with amoxicillin-clavulanate. Hyperbaric oxygen therapy, as primary or adjuvant treatment in association combination with systemic antibiotics or anti-inflammatory therapy, could offer important advantages in treating patients with suspected low-virulent disc infections due to anaerobic microorganisms associated with Type 1 MCs. We believe that hyperbaric oxygenation could contribute to faster resolution of Type 1 MCs and associated pain through multiple effects-including direct antimicrobial effects through formation of reactive oxygen species (ROS), altering the favorable low oxygen tension milieu such that it becomes unfavorable for bacterial growth and survival, and anti-biofilm effects. Additionally, hyperbaric oxygenation could contribute to faster pain resolution via direct and indirect anti-inflammatory effects. As an adjuvant treatment administered in combination with systemic antibiotics, HBOT could increase the sensitivity of Propionibacterium acnes to antimicrobial drugs under hyperoxic conditions, resulting in faster MC resolution. Overall, the faster infection resolution, diminished bacterial load, and anti-inflammatory effects due to reduced cytokine expression and levels of infectious by-products could lead to faster pain resolution following HBOT, and a significant improvement of quality of life in these patients.

PCR ribotypes of Clostridioides difficile across Texas from 2011 to 2018 including emergence of ribotype 255

Clostridioides difficile infection (CDI) is the most prevalent healthcare-associated infection in the United States and carries a significant healthcare system burden. As part of an ongoing, active surveillance system of C. difficile throughout Texas, the objective of this study was to assess changes in C. difficile ribotypes of clinical isolates obtained from hospitalized patients in Texas over the past seven years. Fifty hospitals located in Texas, USA sent C. difficile positive stool specimens to a centralized laboratory for PCR ribotyping and toxin characterization between 2011 and 2018. Data collected included specimen collection date, patient age, and sex. Strain genotypes were compiled, and changes in ribotype distribution over time were assessed. Overall, 7796 samples were ribotyped from predominately female patients (58.4%) aged 62 ± 19 years. Samples were obtained from all geographic regions of Texas including Houston/Southwest region (n = 5129; 85%), Dallas/North Texas (n = 579, 9.6%), Central Texas (n = 164; 2.7%), and South Texas (n = 162; 2.6%). The 10 most common ribotypes comprised 73% of all isolates tested during the study period. The most common ribotypes were 027 (17.5%), followed by 014-020 (16.1%), 106 (11.6%), and 002 (9.1%). The prevalence of ribotypes 027, 001, and 078-126 declined significantly over time, while ribotypes 106 and 054 increased in prevalence (P < 0.001). Furthermore, the emergence of a novel ribotype 255 strain was observed. Differences in ribotype distribution were also noted based on age and geographic distribution (P < 0.001, each). This seven-year study demonstrated changing molecular epidemiology of C. difficile in Texas, including the emergence of a novel ribotype 255.

Elucidation of protein biomarkers for verification of selected biological warfare agents using tandem mass spectrometry

Some pathogens and toxins have the potential to be used as weapons of mass destruction and instigate population-based fear. Efforts to mitigate biothreat require development of efficient countermeasures which in turn relies on fast and accurate methods to detect the biological agents in a range of complex matrices including environmental and clinical samples. We report here an mass spectrometry (MS) based methodology, employing both targeted and shot-gun approaches for the verification of biological agents from the environmental samples. Our shot-gun methodology relied on tandem MS analysis of abundant peptides from the spiked samples, whereas, the targeted method was based on an extensive elucidation of marker proteins and unique peptides resulting in the generation of an inclusion list of masses reflecting relevant peptides for the unambiguous identification of nine bacterial species [listed as priority agents of bioterrorism by Centre for Disease Control and Prevention (CDC)] belonging to phylogenetically diverse genera. The marker peptides were elucidated by extensive literature mining, in silico analysis, and tandem MS (MS/MS) analysis of abundant proteins of the cultivated bacterial species in our laboratory. A combination of shot-gun MS/MS analysis and the targeted search using a panel of unique peptides is likely to provide unambiguous verification of biological agents at sub-species level, even with limited fractionation of crude protein extracts from environmental samples. The comprehensive list of peptides reflected in the inclusion list, makes a valuable resource for the multiplex analysis of select biothreat agents and further development of targeted MS/MS assays.