High Resistance Rates Research Articles

Antibacterial Activity of Methanol Extract of Salvadora Persica (Linn) Stem against Gram-Positive Bacteria Isolated from Oral Infections among the Patients Attending the University Health Clinic of Ahmadu Bello University Zaria

Study’s Novelty/Excerpt This study presents detailed evaluation of the methanol crude extract of Salvadora persica L. (Miswak) for antibacterial effectiveness specifically against gram-positive bacteria from orally infected individuals. It highlights a significant therapeutic efficacy of the extract, evidenced by inhibition zones of 18-22 mm and a minimum inhibitory concentration (MIC) of 25 mg/ml, against pathogens with high resistance rates to conventional antibiotics. Additionally, the research provides comprehensive phytochemical profiling of S. persica, contributing valuable insights into its potential as an alternative treatment for oral infections. Full Abstract Salvadora persica L., commonly referred to as Miswak, is a chewing stick commonly used to maintain dental hygiene. The aim was to determine the antibacterial effectiveness of the methanol crude extract of S. persica against gram-positive bacteria obtained from orally infected individuals who were registered at the University Health Clinic of Ahmadu Bello University. A total of twenty (20) samples were collected from patients who were diagnosed with oral infections. These samples underwent traditional biochemical and microbiological testing. The antibiotic susceptibility test was conducted using the Kirby-Bauer disc diffusion method, and the findings were interpreted following the CLSI standards. The extraction of Salvadora persica L. was carried out using cold maceration with methanol. The crude extract was evaluated using the agar well diffusion and broth dilution techniques. Phytochemical screens were conducted using established procedures. The findings revealed that Staphylococcus aureus had the highest prevalence rate of 60%, whereas Streptococcus sp. had a prevalence rate of 10%. A high level of resistance was detected for amoxicillin (100%), chloramphenicol (85%), ciprofloxacin (60%), ceftriaxone (50%), and gentamycin (47.5%). The cold maceration extraction process yielded in % crude extract yield of 11.59%. The phytochemical elements were saponin, tannin, alkaloid, flavonoid, phenol, heart glycoside, carbohydrate, steroid, and terpenoid. An area of inhibition measuring 18-22mm and a minimum inhibitory concentration (MIC) of 25mg/ml were employed to detect a significant degree of activity. The methanolic extract of Salvadora persica L. has shown significant therapeutic efficacy against gram-positive bacteria recovered from orally infected patients.

The polymicrobial nature of the oral cavity and claws of cats diagnosed by mass spectrometry and next-generation sequencing

Close contact between cats and humans increases the risk of transmission of zoonotic pathogens, through bites and scratches due to the complexity of microorganisms in the oral and nail microbiotas of felines. This study investigated the presence of bacteria and fungi in the oral cavity and claws of 100 apparently healthy cats using conventional and selective microbiological culture media, and next-generation sequencing (NGS) and mass spectrometry (MALDI-TOF MS). Furthermore, antimicrobial susceptibility testing of bacteria isolates was performed by disc diffusion method. In total, 671 bacteria and 33 yeasts were identified by MALDI-TOF MS. Neisseria animaloris (10.8 %), Staphylococcus felis (8.5 %), and Pasteurella multocida (7 %) were the most prevalent bacteria in oral cavity samples (n = 343), while the most common yeast (n = 19) was Candida albicans (68.4 %). Staphylococcus pettenkoferi (13.4 %), Staphylococcus felis (6.4 %), and Staphylococcus simulans (5.8 %) were the prevalent bacteria identified in the claw samples (n = 328), while Rhodotorula mucilaginosa (57.2 %) was the most common yeast (n = 14). NGS predominantly identified the genera Moraxella, Neisseria, Pasteurella, and Fusobacterium in oral cavity samples, whereas enterobacteria and staphylococci were prevalent in nail bed samples. In addition, the genera Capnocytophaga and Bartonella were identified, which have been described in serious human infections secondary to feline aggressions. Levofloxacin, marbofloxacin, and amoxicillin/clavulanic acid were the most effective drugs against the main groups of bacteria identified. Multidrug resistance was observed in 17 % of the bacterial isolates. Furthermore, three staphylococci harboring the methicillin resistance gene mecA were identified. We highlight the complexity of microorganisms inhabiting the oral/claw microbiotas of cats, the high resistance rate of the isolates to conventional antimicrobial agents, and the zoonotic risk of aggressions caused by bites and scratches from domestic cats.

Central role of the ramAR locus in the multidrug resistance in ESBL-Enterobacterales.

The aim of this study was to evaluate the proportion of resistance to a temocillin, tigecycline, ciprofloxacin, and chloramphenicol phenotype called t2c2 that resulted from mutations within the ramAR locus among extended-spectrum β-lactamases-Enterobacterales (ESBL-E) isolated in three intensive care units for 3 years in a French university hospital. Two parallel approaches were performed on all 443 ESBL-E included: (i) the minimal inhibitory concentrations of temocillin, tigecycline, ciprofloxacin, and chloramphenicol were determined and (ii) the genomes obtained from the Illumina sequencing platform were analyzed to determine multilocus sequence types, resistomes, and diversity of several tetR-associated genes including ramAR operon. Among the 443 ESBL-E strains included, isolates of Escherichia coli (n = 194), Klebsiella pneumoniae (n = 122), and Enterobacter cloacae complex (Ecc) (n = 127) were found. Thirty-one ESBL-E strains (7%), 16 K. pneumoniae (13.1%), and 15 Ecc (11.8%) presented the t2c2 phenotype in addition to their ESBL profile, whereas no E. coli presented these resistances. The t2c2 phenotype was invariably reversible by the addition of Phe-Arg-β-naphthylamide, indicating a role of resistance-nodulation-division pumps in these observations. Mutations associated with the t2c2 phenotype were restricted to RamR, the ramAR intergenic region (IR), and AcrR. Mutations in RamR consisted of C- or N-terminal deletions and amino acid substitutions inside its DNA-binding domain or within key sites of protein-substrate interactions. The ramAR IR showed nucleotide substitutions involved in the RamR DNA-binding domain. This diversity of sequences suggested that RamR and the ramAR IR represent major genetic events for bacterial antimicrobial resistance.IMPORTANCEMorbimortality caused by infectious diseases is very high among patients hospitalized in intensive care units (ICUs). A part of these outcomes can be explained by antibiotic resistance, which delays the appropriate therapy. The transferable antibiotic resistance gene is a well-known mechanism to explain the high rate of multidrug resistance (MDR) bacteria in ICUs. This study describes the prevalence of chromosomal mutations, which led to additional antibiotic resistance among MDR bacteria. More than 12% of Klebsiella pneumoniae and Enterobacter cloacae complex strains presented mutations within the ramAR locus associated with a dysregulation of an efflux pump called AcrAB-TolC and a porin: OmpF. These dysregulations led to an increase in antibiotic output notably tigecycline, ciprofloxacin, and chloramphenicol associated with a decrease of input for beta-lactam, especially temocillin. Mutations within transcriptional regulators such as ramAR locus played a major role in antibiotic resistance dissemination and need to be further explored.

Isolation and characterisation of Pseudomonas aeruginosa bacteriophage isolated from Batu Pahat, Johor, Malaysia

The World Health Organization has classified Pseudomonas aeruginosa as a 'Priority One and Critical Pathogen' for which research and design of new antibiotics are urgently needed due to its high rate of antimicrobial resistance. Phage therapy, which uses bacteriophages (phages), has been proposed as an antibacterial agent and shows potential for combating this issue. This study aimed to isolate and characterise bacteriophages from different environmental samples that act specifically against P. aeruginosa. The phages were tested to determine their ability to lyse P. aeruginosa using a spot test. Transmission electron microscopy (TEM) was employed to determine the structure, size and phage family, while specificity and sensitivity tests were conducted using six different bacterial species and 20 clinical multi-drug resistant P. aeruginosa isolates, respectively. Phage PA1 was isolated from Batu Pahat, Johor and using a spot test, PA1 could form clear plaques against P. aeruginosa. PA1 was present in a high titer of 1.06 (± 32.2) x 1010 PFUs/ml. Based on TEM analysis, PA1 was classified as a member of the Myoviridae family. Host-range analysis displayed that PA1 had 100% specificity towards P. aeruginosa and only 45% sensitivity towards different P. aeruginosa clinical isolates. Phage PA1 demonstrated lysis of P. aeruginosa but exhibited a narrow host range, presenting a challenge for phage therapy. A promising approach to overcome this limitation involves using phage cocktails containing multiple strains of phages to broaden the host range and enhance the overall efficacy of phage therapy.

Antibiotic Sensitivity and Biofilm Formation in Pseudomonas aeruginosa Isolated from Wound Infections in Baghdad City

Pseudomonas aeruginosa is considered as the most common gram-negative bacteria that infect hospitalized patients. One hundred sixty six specimens of wound discharge were collected during the period from October to December 2022. Thirty isolates of Pseudomonas aeruginosa have been identified via the cultural, morphological, and biochemical tests. Vitek-2 compact system used to determine the most accurate identification for Pseudomonas aeruginosa, and thirty isolates of Pseudomonas aeruginosa were recognized. In the present study, Pseudomonas aeruginosa was detected in 32.25% of the isolates. All isolates were subjected to antibiotic susceptibility tests to determine their susceptibility to 14 different antibiotics. The results showed total resistance to piperacillin (100%), high resistance rates to ceftazidime (96.7%), tobramycin (96.7%), gentamicin (80%), piperacillin-tazobactam (70%), aztreonam (66.7%), cefoperazone (66.7%), and amikacin (60%). Low resistance rates were found for imipenem (30%), meropenem (43.3%), and gatifloxacin (46.7%), but there was moderate resistance to ciprofloxacin (53.3%), cefotaxime (50%) and colistin (50%). The current investigation determined that among 30 isolates of Pseudomonas aeruginosa, six (20%) developed a weak biofilm, nine (30%) formed a moderate biofilm, and fifteen (50%) formed a strong biofilm. The findings of the present investigation revealed that the vast majority of the isolates with significant antibiotic-resistance can create biofilms.

PREVALENCE OF BACTERIAL VAGINITIS AMONG WOMEN USING DIFFERENT TYPES OF IUDS

Background: A coil, also known as an intrauterine contraceptive device (IUCD or ICD), is a small birth control method that is put into the uterus to stop pregnancy. It usually starts in the endocervix and vagina and spreads up the body, causing endometritis, salpingitis, tubo-ovarian abscesses, parametritis, oophoritis, and/or pelvic peritonitis. objective: The objective of the current study was to investigate the prevalence of bacteria causing vaginitis among women using different types of intra uterine devices Materials and methods: The study was conducted in Kirkuk city from November 1, 2023, to April 30, 2024, using high vaginal swabs from 186 fertile women using intrauterine devices (IUDs). Demographic, medical, and gynecologic histories were recorded, and all patients underwent pelvic examinations. Swabs from the posterior fornix of the vagina were taken for microbiological analysis. The study included women aged 18-45 using IUDs, and excluded those who had received antibiotics, had preexisting systemic or infectious diseases, or experienced bleeding. Ethical approval was obtained, and informed consent was signed by all participants. The swabs were cultured on blood agar , MacConkey agar, Mannitol salt agar and deman rosa sharpe agar and Eosin methylene blue agar and incubated at 37°C for 24 hours. The colonies were picked, purified, and identified through a series of biochemical tests, including Gram staining, motility tests, and enzyme and fermentation tests. The Vitek 2 system was used for microbial identification and susceptibility testing. Results: In a study of 148 women using copper IUDs, 66 (44.59%) tested positive for vaginal swab cultures, while 82 (55.41%) tested negative. Similarly, among 38 women using hormonal IUDs, 17 (44.74%) had positive culture results, and 21 (55.26%) tested negative. Overall, out of 186 women tested, 83 (44.62%) had positive cultures. Among the 83 positive cases, 66 (79.52%) were in copper IUD users, and 17 (20.48%) were in hormonal IUD users. Escherichia coli was the most common bacterium, found in 40.91% of positive cultures, followed by Staphylococcus epidermidis (13.64%), and other bacteria including Staphylococcus aureus, Actinomyces israelii, and Proteus mirabilis, each at 9.09%. In women with positive cultures using copper IUDs, E. coli was most prevalent (47.06%), followed by Staphylococcus aureus and Staphylococcus epidermidis (17.65% each). Among women with positive cultures, 13.25% had diabetes, compared to 4.85% with negative cultures. Hypertension was present in 3.61% of women with positive cultures versus 1.94% with negative cultures. Duration of IUD use also showed a significant correlation with culture results. Women with positive cultures using copper IUDs had the highest percentage in the 1-2 year duration category (43.94%), while those using hormonal IUDs had the highest in the same category (47.06%). Antibiotic sensitivity testing revealed that Imipenem, Meropenem, Tigecycline, and Colistin were 100% effective against E. coli isolates from women using IUDs. However, high resistance rates were observed for Ampicillin/Sulbactam (71.79%) and Ciprofloxacin (84.62%). Ceftolozane/Tazobactam and Gentamicin had relatively high sensitivity rates, while Ceftazidime/Avibactam showed moderate sensitivity. Conclusions The study reveals a significant proportion of women with copper and hormonal IUDs tested positive for vaginal infections, with Escherichia coli being the predominant bacterium isolated,significant differences were noted in the clinical presentation and comorbidities of women with positive cultures compared to those with negative cultures.study identified antibiotics with high sensitivity rates against E. coli isolates, such as Imipenem, Meropenem, Tigecycline, and Colistin, highlighting potential treatment options for IUD-associated infections caused by multidrug-resistant strains. Conversely, antibiotics like Ampicillin/Sulbactam and Ciprofloxacin demonstrated high resistance rates

Fighting Emerging Caspofungin-Resistant Candida Species: Mitigating Fks1-Mediated Resistance and Enhancing Caspofungin Efficacy by Chitosan.

Invasive candidiasis poses a worldwide threat because of the rising prevalence of antifungal resistance, resulting in higher rates of morbidity and mortality. Additionally, Candida species, which are opportunistic infections, have significant medical and economic consequences for immunocompromised individuals. This study explores the antifungal potential of chitosan to mitigate caspofungin resistance in caspofungin-resistant Candida albicans, C. krusei, and C. tropicalis isolates originating from human and animal sources using agar well diffusion, broth microdilution tests, and transmission electron microscope (TEM) analysis of treated Candida cells. Reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) was performed to assess the expression of SAGA complex genes (GCN5 and ADA2) and the caspofungin resistance gene (FKS) in Candida species isolates after chitosan treatment. The highest resistance rate was observed to ketoconazole (80%) followed by clotrimazole (62.7%), fluconazole (60%), terbinafine (58%), itraconazole (57%), miconazole (54.2%), amphotericin B (51.4%), voriconazole (34.28%), and caspofungin (25.7%). Nine unique FKS mutations were detected, including S645P (n = 3 isolates), S645F, L644F, S645Y, L688M, E663G, and F641S (one isolate in each). The caspofungin minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values before chitosan treatment ranged from 2 to 8 µg/mL and 4 to 16 µg/mL, respectively. However, the MIC and MFC values were decreased after chitosan treatment (0.0625-1 µg/mL) and (0.125-2 µg/mL), respectively. Caspofungin MIC was significantly decreased (p = 0.0007) threefold following chitosan treatment compared with the MIC values before treatment. TEM analysis revealed that 0.5% chitosan disrupted the integrity of the cell surface, causing irregular morphologies and obvious aberrant changes in cell wall thickness in caspofungin-resistant and sensitive Candida isolates. The cell wall thickness of untreated isolates was 0.145 μm in caspofungin-resistant isolate and 0.125 μm in sensitive isolate, while it was significantly lower in chitosan-treated isolates, ranging from 0.05 to 0.08 μm when compared with the cell wall thickness of sensitive isolate (0.03 to 0.06 μm). Moreover, RT-qPCR demonstrated a significant (p < 0.05) decrease in the expression levels of histone acetyltransferase genes (GCN5 and ADA2) and FKS gene of caspofungin-resistant Candida species isolates treated with 0.5% chitosan when compared with before treatment (fold change values ranged from 0.001 to 0.0473 for GCN5, 1.028 to 4.856 for ADA2, and 2.713 to 12.38 for FKS gene). A comparison of the expression levels of cell wall-related genes (ADA2 and GCN5) between caspofungin-resistant and -sensitive isolates demonstrated a significant decrease following chitosan treatment (p < 0.001). The antifungal potential of chitosan enhances the efficacy of caspofungin against various caspofungin-resistant Candida species isolates and prevents the development of further antifungal resistance. The results of this study contribute to the progress in repurposing caspofungin and inform a development strategy to enhance its efficacy, appropriate antifungal activity against Candida species, and mitigate resistance. Consequently, chitosan could be used in combination with caspofungin for the treatment of candidiasis.

Multidrug Resistance And Susceptibility Profile of Outpatient Escherichia Coli Clinical Isolates

Background: To gain better understanding about the impact of antibiotic selection pressure on antimicrobial resistance (AMR) in Nigeria, it is important to conduct and review from time to time the susceptibility profile of clinically important bacteria including Escherichia coli. This study investigated the susceptibility and multidrug resistance profile of E. coli isolates from urine samples of patients who received outpatient’s medical services in Abakaliki. Methods: A total of 50 non-duplicate clinical isolates of E. coli from the microbiology laboratory section of a tertiary hospital in Abakaliki, Nigeria was recruited for this study. Susceptibility studies were determined using amoxicillin (20 µg), ceftazidime (30 µg), ciprofloxacin (5 µg), gentamicin (10 µg), nitrofurantoin (300 µg) and erythromycin acid (15 µg) by the modified Kirby–Bauer disk diffusion method. All susceptibility studies were carried out as per the guidelines of the Clinical Laboratory Standard Institute (CLSI). Multidrug resistance was evaluated by the multiple antibiotic resistance index (MARI) calculation. Results: The E. coli isolates showed reduced susceptibility to gentamicin (75%), ciprofloxacin (85%), nitrofurantoin (95%), amoxicillin (100%), erythromycin (100%) and ceftazidime (95%). A total of 12 E. coli isolates were multidrug resistant to clinically important antibiotics in the classes: cephalosporins, macrolides, aminoglycosides, fluoroquinolones, penicillins and nitrofurantoin. Conclusion: We report a high rate of antibiotic resistance of outpatients E. coli isolates which concurrently showed multidrug resistance to important antibiotic classes. These findings have clinical significance and provide a benchmark for future studies on the susceptibility pattern of clinical isolates in Nigeria. This preliminary study reiterates the need to reinvigorate antibiotic stewardship in our local hospitals so as to preserve the clinical efficacy of available antibiotics since it takes years for a new antibiotic to be developed.

Prevalence and characterization of foodborne pathogens isolated from fresh-cut fruits and vegetables in Beijing, China

Pre-cut fresh fruits and vegetables are highly appealing to consumers for their convenience, however, as they are highly susceptible to microbial contamination in processing, the potential risks of foodborne illnesses to public health are not negligible. This study aimed to assess the prevalence, antibiotic susceptibility and molecular characteristics of major foodborne pathogens (Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Salmonella) isolated from fresh-cut fruits and vegetables in Beijing, China. 86 stains were isolated from 326 samples, with S. aureus being the highest prevalence (15.38 %), followed by E. coli (9.23 %) and L. monocytogenes (1.85 %), while no Salmonella was detected. The prevalence by type of food indicated that fruit trays and mixed vegetables were more susceptible to contamination by pathogens. 98 % of S. aureus were resistant to at least of one antibiotic, and showed a high resistance rate to benzylpenicillin (90 %) and oxacillin (48 %). Among 25 E. coli isolates, 57.67 % of which exhibited multi-drug resistance, with common resist to trimethoprim/sulfamethoxazole (66.67 %) and ampicillin (63.33 %). A total of 9 sequence types (STs) and 8 spa types were identified in 35 S. aureus isolates, with ST398-t34 being the predominant type (42.86 %). Additionally, analysis of 25 E. coli isolates demonstrated significant heterogeneity, characterized by 22 serotypes and 18 STs. Genomic analysis revealed that 5 and 44 distinct antibiotic resistance genes (ARGs) in S. aureus and E. coli, respectively. Seven quinolone resistance-determining regions (QRDRs) mutations were identified in E. coli isolates, of which GyrA (S83L) was the most frequently detected. All the S. aureus and E. coli isolates harbored virulence genes. ARGs in S. aureus and E. coli showed a significant positive correlation with plasmids. Furthermore, one L. monocytogenes isolate, which was ST101 and serogroupIIc from watermelon sample, harbored virulence genes (inlA and inlB) and LIPI-1 pathogenic islands (prfA, plcA, hly and actA), which posed potential risks for consumer's health. This study focused on the potential microbial risk of fresh-cut fruits and vegetables associated with foodborne diseases, improving the scientific understanding towards risk assessment related to ready-to-eat foods.

The Etiologic Organisms, Risk Factors, and Outcomes of Nosocomial Bloodstream Infections in Pediatric Patients

Background Much of the knowledge regarding pediatric healthcare-associated infections is based on studies conducted in adults. Here, we investigated clinical risk factors and etiologic organisms, focusing on antibiotic and antifungal resistance in pediatric patients with nosocomial bloodstream infections (nBSIs) in pediatric intensive care units (PICUs). Methods A retrospective evaluation was conducted on pediatric patients with nBSI in the PICUs of a tertiary referral hospital. Results A total of 69 nBSI episodes in 65 patients were observed during the study period. Of these, a total of 40 (57.97%) were caused by Gram-negative bacteria, 6 (8.7%) by Gram-positive bacteria, and 23 (33.33%) by Candida species. The rankings of Gram-negative bacteria were Klebsiella pneumoniae (37.5%), Acinetobacter baumannii (22.5%), and Serratia marcescens (12.5%). Carbapenem resistance was found to be common among K. pneumoniae (40%) and all Acinetobacter species. Most children (54.41%) had spent &gt;28 days in the PICU at the time of diagnosis of nBSI. The presence of central venous catheters was significantly associated with fungal nBSI (P = 0.047). Conclusions A high rate of antimicrobial resistance was observed among pathogens. A central venous catheter was associated with fungemia in children hospitalized in PICUs. Prolonged hospital stay before the diagnosis of BSI and the use of medical devices were found to be common in fungal infections.

Current trends in antimicrobial resistance of ESKAPEEc pathogens from bloodstream infections – Experience of a tertiary care centre in North India

IntroductionBloodstream infections (BSI) due to ESKAPEEc pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanni, Pseudomonas aeruginosa, Enterobacter spp. and Escherichia coli), cause significant mobility and mortality worldwide and are among the most common healthcare associated infections. Rising rates of antimicrobial resistance (AMR) in India are alarming, because of the high infection rates and poor control of antibiotic use. This single-centre, retrospective study was undertaken to identify the patterns of distribution and antimicrobial resistance of ESKAPEEc pathogens in bloodstream infections. MethodologyBlood samples from patients with suspected BSI were cultured and antimicrobial susceptibility testing was performed on automated systems (BD Bactec Fx/BactAlert 3D and Vitek2). The microbiological data on bacterial BSI was retrieved from the laboratory records and antimicrobial resistance profiles were analysed. Results10.7% of the blood culture samples showed bacterial growth during the study period (adult > paediatric and intensive care unit (ICU) > ward > outpatient department (OPD)). E. coli (24%) and K. pneumoniae (20.5%) were the predominant species isolated, followed by S. aureus (9.5%) and A. baumanni (9%). High rates of resistance to third generation cephalosporins, β-lactam-β-lactamase inhibitor combinations (BL-BLI) and carbapenems was observed, in Gram-negative isolates, especially from ICU patients. Methicillin-resistant S. aureus (MRSA) isolates increased from 67% to 88% over the five-year period. Vancomycin-resistance among Enterococcus isolates also escalated to 40% in 2022 with 11% linezolid resistance. ConclusionThe study revealed that more than 77% of bloodstream infections were caused by ESKAPEEc pathogens, with high rates of resistance to most antimicrobials. This reinforces the importance of monitoring the frequency of bacteria and antibiograms in individual treatment and hospital infection control programs.

Determination of antimicrobial susceptibility and virulence-related genes of Trueperella pyogenes strains isolated from various clinical specimens in animals

In this study, a total of 32 Trueperella pyogenes strains isolated from different disease specimens in cattle, sheep and goats were examined. Antimicrobial susceptibility of the isolates to 10 antimicrobials were determined using the E-test method and MIC values of the antimicrobials were investigated. The genes that play a role in the antimicrobial resistance or virulence of T. pyogenes were determined by PCR using gene specific primers. In the study, all the isolates were susceptible to penicillin and cephalosporin. The highest resistance rate in the isolates was determined against streptomycin (56.25%) and tetracycline (53.12%) and MIC90 values for these antimicrobials were found to be &amp;gt;256 μg/ml and 12 μg/ml, respectively. The ermX gene was found to be positive in 8 (80%) of 10 isolates that were resistant to macrolide group antimicrobials. Among 20 aminoglycoside resistant isolates, aadA1, aadA9, strA-strB, and aac(6’)-aph(2’’) genes were determined in 5 (25%), 14 (70%), 7 (35%) and 1 (5%) of the isolates, respectively. When the presence of virulence-related genes in the isolates was examined, nanP (93.75%), fimA (93.75%) and plo (90.62%) genes were detected in the majority of the isolates. While the cbpA gene was negative in all isolates, the fimG gene was found in a limited number of the isolates (15.62%). It was concluded that streptomycin and tetracycline resistance should be considered in T. pyogenes isolates. Also, nanP, fimA and plo genes may have an important role in the pathogenesis of the infections.

The Evolving Challenge of Appropriate Antibiotics Use in Hospitalized COVID-19 Patients: A Systematic Literature Review.

The issue of bacterial infections in COVID-19 patients has received increasing attention. Scant data are available on the impact of bacterial superinfection and antibiotic administration on the outcome of hospitalized COVID-19 patients. We conducted a literature review from 1 January 2022 to 31 March 2024 to assess the current burden of bacterial infection and the evidence for antibiotic use in hospitalized COVID-19 patients. Published articles providing data on antibiotic use in COVID-19 patients were identified through computerized literature searches with the search terms [(antibiotic) AND (COVID-19)] or [(antibiotic treatment) AND (COVID-19)]. PubMed and SCOPUS databases were searched from 1 January 2022 to 31 March 2024. No attempt was made to obtain information about unpublished studies. English language restriction was applied. The quality of the included studies was evaluated by the tool recommended by the Joanna Briggs Institute. Both quantitative and qualitative information were summarized by means of textual descriptions. Five hundred fifty-one studies were identified, and twenty-nine studies were included in this systematic review. Of the 29 included studies, 18 studies were on the prevalence of bacterial infection and antibiotic use in hospitalized COVID-19 patients; 4 studies reported on the efficacy of early antibiotic use in COVID-19; 4 studies were on the use of sepsis biomarkers to improve antibiotic use; 3 studies were on the efficacy of antimicrobial stewardship programs and predictive models among COVID-19-hospitalized patients. The quality of included studies was high in 35% and medium in 62%. High rates of hospital-acquired infections were reported among COVID-19 patients, ranging between 7.5 and 37.7%. A high antibiotic resistance rate was reported among COVID-19 patients developing hospital-acquired infections, with a high in-hospital mortality rate. The studies evaluating multi-faceted antimicrobial stewardship interventions reported efficacy in decreasing antibiotic consumption and lower in-hospital mortality.

Combining EHMT and PARP Inhibition: A Strategy to Diminish Therapy-Resistant Ovarian Cancer Tumor Growth while Stimulating Immune Activation.

Despite the success of Poly-ADP-ribose polymerase inhibitors (PARPi) in the clinic, high rates of resistance to PARPi presents a challenge in the treatment of ovarian cancer, thus it is imperative to find therapeutic strategies to combat PARPi resistance. Here, we demonstrate that inhibition of epigenetic modifiers Euchromatic histone lysine methyltransferases 1/2 (EHMT1/2) reduces the growth of multiple PARPi-resistant ovarian cancer cell lines and tumor growth in a PARPi-resistant mouse model of ovarian cancer. We found that combinatory EHMT and PARP inhibition increases immunostimulatory dsRNA formation and elicits several immune signaling pathways in vitro. Using epigenomic profiling and transcriptomics, we found that EHMT2 is bound to transposable elements, and that EHMT inhibition leads to genome-wide epigenetic and transcriptional derepression of transposable elements. We validated EHMT-mediated activation of immune signaling and upregulation of transposable element transcripts in patient-derived, therapy-naïve, primary ovarian tumors, suggesting potential efficacy in PARPi-sensitive disease as well. Importantly, using multispectral immunohistochemistry, we discovered that combinatory therapy increased CD8 T cell activity in the tumor microenvironment of the same patient-derived tissues. In a PARPi-resistant syngeneic murine model, EHMT and PARP inhibition combination inhibited tumor progression and increased Granzyme B+ cells in the tumor. Together, our results provide evidence that combinatory EHMT and PARP inhibition stimulates a cell autologous immune response in vitro, is an effective therapy to reduce PARPi resistant ovarian tumor growth in vivo, and promotes anti-tumor immunity activity in the tumor microenvironment of patient-derived ex vivo tissues of ovarian cancer.

Genomic characterization and resistance features of Streptococcus agalactiae isolated from non-pregnant adults in Shandong, China

BackgroundStreptococcus agalactiae is a recognized pathogen that primarily affects infants and pregnant women. However, its increasingly important role in causing invasive infections among non-pregnant adults has become a significant health concern due to the severity and variety of its clinical impacts. MethodsNonduplicate S. agalactiae clinical strains associated with clinical infections (n = 139) were isolated from non-pregnant adults in Shandong, China. Antibiotic susceptibility testing, whole-genome sequencing and genomic analyses were conducted to characterize the genome and identify resistance features of these strains. ResultsThe strains exhibited universal susceptibility to penicillin, ampicillin, cefotaxime, meropenem, linezolid and vancomycin. Notably, high resistance rates were observed for erythromycin (91.4%), clindamycin (89.2%), levofloxacin (84.2%), tetracycline (54.0%) and, to a lesser extent, chloramphenicol (12.9%). Serotyping revealed seven serotypes and one non-typeable strain. Serotypes Ia, Ib, III and V predominated, representing 95.7% of the strains. Nineteen sequence types were categorized into seven clonal complexes, with CC10 being the most prevalent at 48.9%. The resistance genes mreA (100%), ermB (70.5%) and tetM (46.0%) were commonly detected. All the isolates carried at least one pilus backbone determinant and one alpha-like protein gene, with the PI-1+PI-2a and the bca gene being the most frequent at 84.2% and 54.7%, respectively. ConclusionsWhile S. agalactiae strains in non-pregnant adults retain sensitivity to β-lactam antibiotics, the elevated resistance to erythromycin, clindamycin, levofloxacin and tetracycline is concerning. Given the growing elderly population worldwide, the burden of S. agalactiae infections is significant. Continuous surveillance of serotype distribution and antibiotic resistance patterns is imperative for targeted prevention and therapeutic strategies.

Occurrence of antibiotic-resistant bacteria in household greywater discharged into the environment in Burkina Faso's Sahel region

ABSTRACT The prevalence and antibiotic resistance of Salmonella spp. and Staphylococcus spp. from greywater were investigated in Africa's Sahel region, Burkina Faso. A total of 36 and 56 isolates of Salmonella spp. and Staphylococcus spp. were isolated from greywater, respectively. From the Salmonella spp. isolates, resistance was most frequently observed against vancomycin (69%), ampicillin (61%), cefoxitin (42%), trimethoprine/sulfamethoxazole (36%), amoxicillin-clavunal acid (33%) and tetracycline (33%). For all Staphylococcus spp. isolates, the highest rate of resistance was against penicillin (55.36%) followed by oxacillin (48.21%) and clindamycin (30.36%). In addition, 75% of the isolated Salmonella spp. strains were resistant to at least two antibiotics of different families, while 30.35% of Staphylococcus spp. strains were multidrug-resistant (MDR). Overall, this is one of the first studies reporting the presence of MDR bacteria in untreated greywater discharged from domestic activities in Burkina Faso. Our results show that untreated greywater can contain bacteria resistant to antibiotics used in therapeutic care. Therefore, uncontrolled discharge of untreated greywater into the environment could lead to the dissemination of resistant bacteria and resistance genes in the environment and increase the risk of human exposure to antimicrobial resistance.

Molecular characteristics and drug susceptibility analysis of Streptococcus agalactiae from respiratory specimen sources

To study the carriage status of drug susceptibility, clonal complex groups, serotypes, surface proteins and virulence genes of Streptococcus agalactiae from respiratory specimen sources. A total of 35 strains of S.agalactiae meeting the criteria were collected from 3 hospitals in 2 locations, Tangshan and Jinan. The age span of the patients was 3 days-92 years, and the percentage of elderly patients≥60 years was 71.5%.The susceptibility to 9 antimicrobial drugs was measured and analyzed using the micro broth dilution method. The strains were 100.0% sensitive to penicillin, linezolid, vancomycin, and ceftriaxone; However, it exhibits high resistance rates to erythromycin, clindamycin and levofloxacin, at 97.1%, 85.7% and 82.9% respectively; and the resistance rates to tetracycline and chloramphenicol were 34.3% and 14.2%, respectively. Genome sequence determination and analysis showed that 16 resistance genes were detected in 35 strains, among which: macrolide and lincosamide resistance genes were mainly ermB, with a carrying rate of 74.2%; tetracycline resistance genes were mainly tetM, with a carrying rate of 25.7%; in addition, the mutation rates of the quinolone resistance determinants gyrA and parC were 88.5% and 85.7%, respectively. 35 strains belonged to 6 ST types and 4 clonal groups, with CC10/ST10 as the main one, accounting for 62.8%; they contained 4 serotypes of Ⅰb, Ⅱ, Ⅲ, and Ⅴ, as well as 1 untyped strain, with serotype Ⅰb as the main one, accounting for 65.7%. The strains carried three pilus types, PI1+PI2a, PI2a and PI2b types, respectively, and detected five surface proteins, alpha, alp1, rib, srr, and rdf_0594, and seven virulence factors, cba, cfb, cylE, fbsA, hylB, lmb, and pavA. Overall, S.agalactiae isolated from respiratory tract specimens is predominantly sourced from elderly patients, with CC10 strains being most prevalent. These strains harbor multiple drug-resistant and virulence genes, demonstrating elevated resistance rates to macrolides, lincosamides, and quinolones. This emphasizes the necessity for vigilant attention to the health threat posed by S. agalactiae from respiratory tract speciments of elderly patients.

Emergence of Plasmid-Mediated Quinolone Resistance (PMQR) Genes in Campylobacter coli in Tunisia and Detection of New Sequence Type ST13450.

The aim of this study is to investigate the occurrence of plasmid mediated quinolone resistance (PMQR) determinants in Campylobacter coli isolates collected from broilers, laying hens and poultry farm environments. One hundred and thirty-nine C. coli isolates were isolated from broilers (n = 41), laying hens (n = 53), eggs (n = 4) and the environment (n = 41) of 23 poultry farms located in northeastern of Tunisia. Antimicrobial susceptibility testing was performed on all isolates according to the recommendation of the European Committee on Antimicrobial Susceptibility Testing guidelines. The detection of PMQR genes: qnrA, qnrB, qnrC, qnrD, qnrS, qepA, and aac(6)-Ib gene was performed using polymerase chain reaction (PCR) and specific primers. aac(6')-Ib amplicons were further analyzed by digestion with BtsCI to identify the aac(6')-Ib-cr variant. Mutations in GyrA and the occurrence of RE-CmeABC efflux pump were determined by mismatch amplification mutation assay (MAMA) PCR and PCR, respectively. In addition, eleven isolates were selected to determine their clonal lineage by MLST. The 139 C. coli isolates were resistant to ciprofloxacin, and 86 (61.8%) were resistant to nalidixic acid. High rates of resistance were also observed toward erythromycin (100%), azithromycin (96.4%), tetracycline (100%), chloramphenicol (98.56%), ampicillin (66.1%), amoxicillin-clavulanic acid (55.39%), and kanamycin (57.55%). However, moderate resistance rates were observed for gentamicin (9.35%) and streptomycin (22.3%). All quinolone-resistant isolates harbored the Thr-86-Ile amino acid substitution in GyrA, and the RE-CmeABC efflux pump was detected in 40.28% of isolates. Interestingly, the qnrB, qnrS, qepA, and aac(6')-Ib-cr were detected in 57.7%, 61.15%, 21.58%, and 10% of isolates, respectively. The eleven isolates studied by MLST belonged to a new sequence type ST13450. This study described for the first time the occurrence of PMQR genes in C. coli isolates in Tunisia and globally.

Revealing roles of S-layer protein (SlpA) in Clostridioides difficile pathogenicity by generating the first slpA gene deletion mutant.

Clostridioides difficile infection (CDI) with high morbidity and high mortality is an urgent threat to public health, and C. difficile pathogenesis studies are eagerly required for CDI therapy. The major surface layer protein, SlpA, was supposed to play a key role in C. difficile pathogenesis; however, a lack of isogenic slpA mutants has greatly hampered analysis of SlpA functions. In this study, the whole slpA gene was successfully deleted for the first time via CRISPR-Cas9 system. Deletion of slpA in C. difficile resulted in smaller, smother-edged colonies, shorter bacterial cell size, and aggregation in suspension. For life cycle, the mutant demonstrated lower growth (changes of optical density at 600 nm, OD600) but higher cell density (colony-forming unit, CFU), decreased toxins production, and inhibited sporulation. Moreover, the mutant was more impaired in motility, more sensitive to vancomycin and Triton X-100-induced autolysis, releasing more lactate dehydrogenase. In addition, SlpA deficiency led to robust biofilm formation but weak adhesion to human host cells.IMPORTANCEClostridioides difficile infection (CDI) has been the most common hospital-acquired infection, with a high rate of antibiotic resistance and recurrence incidences, become a debilitating public health threat. It is urgently needed to study C. difficile pathogenesis for developing efficient strategies as CDI therapy. SlpA was indicated to play a key role in C. difficile pathogenesis. However, analysis of SlpA functions was hampered due to lack of isogenic slpA mutants. Surprisingly, the first slpA deletion C. difficile strain was generated in this study via CRISPR-Cas9, further negating the previous thought about slpA being essential. Results in this study will provide direct proof for roles of SlpA in C. difficile pathogenesis, which will facilitate future investigations for new targets as vaccines, new therapeutic agents, and intervention strategies in combating CDI.

Crebanine, an aporphine alkaloid, induces cancer cell apoptosis through PI3K-Akt pathway in glioblastoma multiforme.

Glioblastoma multiforme (GBM) is one of the most prevalent and lethal primary central nervous system malignancies. GBM is notorious for its high rates of recurrence and therapy resistance and the PI3K/Akt pathway plays a pivotal role in its malignant behavior. Crebanine (CB), an alkaloid capable of penetrating the blood-brain barrier (BBB), has been shown to have inhibitory effects on proinflammatory molecules and multiple cancer cell lines via pathways such as PI3K/Akt. This study aims to investigate the efficacy and mechanisms of CB treatment on GBM. It is the first study to elucidate the anti-tumor role of CB in GBM, providing new possibilities for GBM therapy. Through a series of experiments, we demonstrate the significant anti-survival, anti-clonogenicity, and proapoptotic effects of CB treatment on GBM cell lines. Next-generation sequencing (NGS) is also conducted and provides a complete list of significant changes in gene expression after treatment, including genes related to apoptosis, the cell cycle, FoxO, and autophagy. The subsequent protein expressions of the upregulation of apoptosis and downregulation of PI3K/Akt are further proved. The clinical applicability of CB to GBM treatment could be high for its BBB-penetrating feature, significant induction of apoptosis, and blockage of the PI3K/Akt pathway. Future research is needed using in vivo experiments and other therapeutic pathways shown in NGS for further clinical or in vivo studies.