Assessment of multidrug resistance in bacterial isolates from urinary tract-infected patients

Production of polyhydroxyalkanoate by mixed cultivation of Brevundimonas diminuta R79 and Pseudomonas balearica R90

The microflora in the activated sludge of propylene oxide saponification wastewater is characterized by a clear succession after enrichment and domestication, and the specifically enriched strains can significantly increase the yield of polyhydroxyalkanoate. In this study, Pseudomonas balearica R90 and Brevundimonas diminuta R79, which are dominant strain after domestication, were selected as models to examine the interactive mechanisms associated with the synthesis of polyhydroxyalkanoate by co-cultured strains. RNA-Seq analysis revealed the up-regulated expression of the acs and phaA genes of strains R79 and R90 in the co-culture group, which enhanced their utilization of acetic acid and synthesis of poly-β-hydroxybutyrate. Cell dry weight and the yield of poly-β-hydroxybutyrate in the co-culture group were accordingly considerably higher than those in the respective pure culture groups. In addition, two-component system, quorum-sensing, flagellar synthesis-related, and chemotaxis-related genes were enriched in strain R90, thereby indicating that compared with the R79 strain, R90 can adapt more rapidly to a domesticated environment. Expression of the acs gene was higher in R79 than in R90, and consequently, strain R79 could more efficiently assimilate acetate in the domesticated environment, and thus predominated in the culture population at the end of the fermentation period.

Antimicrobial peptides derived from microalgae for combating antibiotic resistance: Current status and prospects

Microalgae are photosynthetic cell factories that produce a spectrum of bioactive compounds extensively used for various applications. Owing to the increase in antibiotic resistance among microbial pathogens, there is a significant thrust for identifying new treatment strategies, and antimicrobial peptides (AMPs) generation is one such method. These AMPs have multiple roles and are active against bacteria, fungi, and viruses. Such peptides synthesized in microalgae have a significant role in medical application, managing aquaculture-associated diseases, and the food industry. To increase their effectiveness and novel peptides, genetically modified microalgae are used as cell factories. With the advancement of new technologies like the CRISPR-Cas system, new avenues are opened for developing novel AMPs using microalgae. This review gives us insight into the various AMPs produced by microalgae and multiple technologies involved in creating such therapeutically essential molecules.

Similarities in Bacterial Uropathogens and Their Antimicrobial Susceptibility Profile in Diabetics and Their Non-Diabetic Caregivers at a National Diabetes Management and Research Centre, Accra-Ghana

BACKGROUND

Diabetes mellitus has some damaging effects on the genitourinary system and has been found to have adverse effects on the host immune system, resulting in higher risk of infections including urinary tract infections (UTI). Incidences of UTI caused by bacteria have been increasingly reported globally and the abuse of antibiotics leading to evolving resistant strains of antibiotics is a public health challenge for the management of this condition. Information on the difference in types of bacterial agents causing UTI in diabetic patients and non-diabetic individuals, and their susceptibility profiles, will facilitate effective management among these groups of patients. Therefore, this study aimed at determining the difference in prevalence of UTI, the causative bacteria, and their antimicrobial susceptibility profiles in diabetic patients and non-diabetic individuals at a diabetes management center.

METHODS

This was a prospective cross-sectional study conducted amongst 100 diagnosed diabetic patients and 100 non-diabetic individuals. Urine sample was collected aseptically and analyzed microbiologically for the presence of urinary tract bacterial pathogens. Drug susceptibility testing was conducted on the isolates by the Kirby Bauer method to ascertain the antibiotic susceptibility patterns.

RESULTS

Among the diabetic and non-diabetic individuals, urinary tract bacterial pathogens were observed in 28.0% and 26.0% of samples, respectively. The organisms were in the following proportions for diabetic and non-diabetic individuals, respectively: E. coli (14/28, 50% and 8/26, 30.7%), S. aureus (2/28, 7.1% and 4/26, 15.4%), K. pneumoniae (4/28, 14.3% and 8/26, 30.7%), K. ozoenae (2/28, 7.14% and 0/26, 0%), K. oxytoca (0/28, 0% and 4/26, 15.4%) and C. urealyticum (6/28, 21.4% and 2/26, 7.69%). The difference between the proportions of bacteria isolated was, however, not statistically significant (p-value = 0.894). Bacteria isolated from both diabetic and non-diabetic individuals were highly susceptible to most of the antibiotics tested, especially nitrofurantoin, cefuroxime, ceftriaxone, and cefotaxime.

CONCLUSION

This study has shown that similarities exist in prevalence of UTI, the causative bacteria, and their antimicrobial susceptibility patterns amongst diabetic patients and non-diabetic individuals at a diabetes management center. These data will help in the management of UTI among these individuals.

Urinary Catheters Coated with a Novel Biofilm Preventative Agent Inhibit Biofilm Development by Diverse Bacterial Uropathogens

Despite the implementation of stringent guidelines for the prevention of catheter-associated (CA) urinary tract infection (UTI), CAUTI remains one of the most common health care-related infections. We previously showed that an antimicrobial/antibiofilm agent inhibited biofilm development by Gram-positive and Gram-negative bacterial pathogens isolated from human infections. In this study, we examined the ability of a novel biofilm preventative agent (BPA) coating on silicone urinary catheters to inhibit biofilm formation on the catheters by six different bacterial pathogens isolated from UTIs: three Escherichia coli strains, representative of the most common bacterium isolated from UTI; one Enterobacter cloacae, a multidrug-resistant isolate; one Pseudomonas aeruginosa, common among patients with long-term catheterization; and one isolate of methicillin-resistant Staphylococcus aureus, as both a Gram-positive and a resistant organism. First, we tested the ability of these strains to form biofilms on urinary catheters made of red rubber, polyvinyl chloride (PVC), and silicone using the microtiter plate biofilm assay. When grown in artificial urine medium, which closely mimics human urine, all tested isolates formed considerable biofilms on all three catheter materials. As the biofilm biomass formed on silicone catheters was 0.5 to 1.6 logs less than that formed on rubber or PVC, respectively, we then coated the silicone catheters with BPA (benzalkonium chloride, polyacrylic acid, and glutaraldehyde), and tested the ability of the coated catheters to further inhibit biofilm development by these uropathogens. Compared with the uncoated silicone catheters, BPA-coated catheters completely prevented biofilm development by all the uropathogens, except P. aeruginosa, which showed no reduction in biofilm biomass. To explore the reason for P. aeruginosa resistance to the BPA coating, we utilized two specific lipopolysaccharide (LPS) mutants. In contrast to their parent strain, the two mutants failed to form biofilms on the BPA-coated catheters, which suggests that the composition of P. aeruginosa LPS plays a role in the resistance of wild-type P. aeruginosa to the BPA coating. Together, our results suggest that, except for P. aeruginosa, BPA-coated silicone catheters may prevent biofilm formation by both Gram-negative and Gram-positive uropathogens.

Dibenzyl (benzo [d] thiazol-2-yl (hydroxy) methyl) phosphonate (DBTMP) showing anti-S. aureus and anti-biofilm properties by elevating activities of serine protease (SspA) and cysteine protease staphopain B (SspB)

Staphylococcus aureus biofilms are the pathogenic factor in the spread of infection and are more pronounced in multidrug-resistant strains of S. aureus, where high expression of proteases is observed. Among various proteases, Serine protease (SspA) and cysteine protease Staphopain B (SspB) are known to play a key role in the biofilm formation and removal of biofilms. In earlier studies, we have reported Dibenzyl (benzo [d] thiazol-2-yl (hydroxy) methyl) phosphonate (DBTMP) exhibits anti-S. aureus and anti-biofilm properties by elevating the expression of the protease. In this study, the effect of DBTMP on the activities of SspA, and SspB of S. aureus was evaluated. The SspA and SspB genes of S. aureus ATCC12600 were sequenced (Genbank accession numbers: MZ456982 and MW574006). In S. aureus active SspA is formed by proteolytic cleavage of immature SspA, to get this mature SspA (mSspA), we have PCR amplified the mSspA sequence from the SspA gene. The mSspA and SspB genes were cloned, expressed, and characterized. The pure recombinant proteins rSspB and rmSspA exhibited a single band in SDS-PAGE with a molecular weight of 40 and 30 KD, respectively. The activities of rmSspA and rSspB are 32.33 and 35.45 Units/mL correspondingly. DBTMP elevated the activities of rmSspA and rSspB by docking with respective enzymes. This compound disrupted the biofilms formed by the multidrug-resistant strains of S. aureus and further prevented biofilm formation. These findings explain that DBTMP possesses anti-S. aureus and anti-biofilm features.

Role of gene regulation and inter species interaction as a key factor in gut microbiota adaptation

Gut microbiota is a class of microbial flora present in various eukaryotic multicellular complex animals such as human beings. Their community's growth and survival are greatly influenced by various factors such as host-pathogen, pathogen-environment and genetic regulation. Modern technologies like metagenomics have particularly extended our capacity to uncover the microbial treasures in challenging conditions like communities surviving at high altitude. Molecular characterizations by newly developed sequencing tools have shown that this complex interaction greatly influences microbial adaptation to the environment. Literature shows that gut microbiota alters the genetic expression and switches to an alternative pathway under the influence of unfavorable conditions. The remarkable adaptability of microbial genetic regulatory networks enables them to survive and expand in tough and energy-limited conditions. Variable prevalence of species in various regions has strengthened this initial evidence. In view of the interconnection of the world in the form of a global village, this phenomenon must be explored more clearly. In this regard, recently there has been significant addition of knowledge to the field of microbial adaptation. This review summarizes and shed some light on mechanisms of microbial adaptation via gene regulation and species interaction in gut microbiota.

Antimicrobial Resistance Patterns, Extended-Spectrum Beta-Lactamase Production, and Associated Risk Factors of Klebsiella Species among UTI-Suspected Patients at Bahir Dar City, Northwest Ethiopia

Introduction

Klebsiella species cause pneumonia, UTI, and septicemia in human beings. Beta-lactam drugs are used extensively to treat patients infected with Klebsiella, but most of the Klebsiella species are resistant to third- and fourth-generation cephalosporins and monobactams to which data are scarce in the study area.

Objective

To determine the prevalence, antimicrobial resistance, ESBL production, and associated risk factors of Klebsiella species among UTI-suspected patients in Bahir Dar City, Northwest Ethiopia.

Methods

A multi-institution-based prospective cross-sectional study was conducted from January to May 2019. Midstream urines were collected from 385 patients and inoculated onto CLED and MacConkey agars. Identification of growth was done by a battery of biochemical tests. Antimicrobial resistance and ESBL production patterns were determined by using the disc-diffusion method on Mueller–Hinton agar. Quality of data was maintained by following SOPs and using Klebsiella pneumoniae (ACTT700603). Logistic regression statistical analysis was done using the SPSS, version 25, statistical package. A pvalue ≤ 0.05 was considered statistically significant.

Results

The median age of the study participants was 32 years. Majority of them were female, urban residents, and unable to read and/or write. The total Klebsiella species detected were 38 (9.9%). Of which, 25 (65.8%) were Klebsiella pneumoniae, followed by 6 (15.8%) Klebsiella ozaenae. 20 (80%), 19 (76%), and 19 (76%) Klebsiella pneumoniae showed resistance to amoxicillin/clavulanic acid, ampicillin, and cotrimoxazole, respectively. All K. oxytoca were resistant to ampicillin, and all K. rhinoscleromatis were resistant to cefoxitin and cefotaxime. Klebsiella species that showed resistance to ≥3 antimicrobials were 26 (68%). ESBL-producing Klebsiella species were 10 (26.3%). Patients who had history of antibiotic use, hospitalization, and tight dressing habit had more risk of getting UTI (p < 0.05) than their counterparts.

Conclusions

Overall UTI prevalence in our study was lower than that of previous Ethiopian studies. High MDR and ESBL-producing Klebsiella species were detected. Patients' history of antibiotic use, hospitalization, and tight dressing habit were risk factors for UTI. It calls up for improving prevention/control systems of Klebsiella species.

Detection of AmpC and ESBL-producing Enterobacterales isolated from urinary tract infections in Tunisia

Urinary tract infections (UTIs) are the most frequent human infections in community and hospitals. This study aimed to determine the distribution of bacterial uropathogens among urinary tract infections diagnosed within the regional hospital Houcine Bouzaiene (Gafsa, South West Tunisia) during a survey of 54 days from the 8th of November to the 31st of December 2017. Enterobacterales strains were tested for antimicrobial resistance by disk diffusion method and extended-spectrum β-lactamase (ESBL) production was tested by double-disc synergy test. Strains were further subjected to a molecular assessment of ESBL and AmpC β-lactamase production by PCR. Overall, 173 bacterial isolates were studied, out of which 91.3% were Enterobacterales. Escherichia coli was the dominant pathogen, followed by Klebsiella pneumoniae. High to moderate resistance rates were observed, ranging from 66% to 90.7% for penicillins, from 6.7% to 18.6% for cephalosporins and from 16.2% to 25.4% for fluoroquinolones. Enterobacterales with decreased susceptibility to third-generation cephalosporins (3rd GC) carried several resistance genes: blaCTX-M group 1 and group 9, and ACC and FOX AmpC β-lactamase genes. Overall, ESBLs and AmpC β-lactamases were detected in 57% and 14% of the 3rd GC-resistant isolates, respectively. This study proved the high potential of K. pneumaniae species to develop resistance against commonly used antibiotics. Thus, rigorous monitoring of the antibiotic resistance of clinical pathogens have to be implemented in Tunisia. Our results are very relevant to evaluate efficiency of the Tunisian therapeutic strategies against UTIs and adapt them to the emerging problem of antimicrobial resistance.

Nanotechnology-based immunotherapies to combat cancer metastasis

Emerging concepts in nanotechnology have gained particular attention for their clinical translation of immunotherapies of cancer, autoimmune and infectious diseases. Several nanoconstructs have been engineered with unique structural, physicochemical, and functional features as robust alternatives for conventional chemotherapies. Traditional cancer therapies like chemotherapy, radiotherapy, and ultimately surgery are the most widely practiced in biomedical settings. Biomaterials and nanotechnology have introduced vehicles for drug delivery and have revolutionized the concept of the modern immunotherapeutic paradigm. Various types of nanomaterials, such as nanoparticles and, more specifically, drug-loaded nanoparticles are becoming famous for drug delivery applications because of safety, patient compliance, and smart action. Such therapeutic modalities have acknowledged regulatory endorsement and are being used in twenty-first-century clinical settings. Considering the emerging concepts and landscaping potentialities, herein, we spotlight and discuss nanoparticle-based immunotherapies as a smart and sophisticated drug delivery approach to combat cancer metastasis. The introductory part of this manuscript discusses a broad overview of cancer immunotherapy to understand better the tumor microenvironment and nanotechnology-oriented immunomodulatory strategies to cope with advanced-stage cancers. Following that, most addressable problems allied with conventional immunotherapies are given in comparison to nanoparticle-based immunotherapies. The later half of this work comprehensively highlights the requisite delivery of various bioactive entities with particular cases and examples. Finally, this review also encompasses a comprehensive concluding overview and future standpoints to strengthen a successful clinical translation of nanoparticle-based immunotherapies as a smart and sophisticated drug delivery approach.