High Resistance Rates Research Articles

The increasing burden of group B Streptococcus from 2013 to 2023: a retrospective cohort study in Beijing, China.

Group B Streptococcus (GBS) is a leading pathogen responsible for fatal infections in newborns primarily due to vertical transmission from colonized mothers. Cases of invasive GBS infections in adults have also increased and attracted attention recently. To comprehensively understand the evolving burden of vaginal GBS carriage in pregnant and non-pregnant women, as well as the trends in invasive GBS diseases and antibiotic resistance in China, we conducted a retrospective study using data from a large tertiary hospital in Beijing from 2013 to 2023. Over the past decade, improvements in GBS screening methods for pregnant women have significantly increased the GBS recovery rate. The detection rate of GBS and its proportion among vaginal pathogens have shown a gradual increase in GBS colonization in both pregnant and non-pregnant women. An analysis of vaginal pathogen composition revealed variations in GBS prevalence across different age groups, as well as a potential competitive relationship between GBS and Enterococcus faecalis in the vaginal environment. Additionally, we analyzed 165 invasive GBS cases, including three in newborns. The incidence of invasive GBS cases has risen since 2016, particularly among individuals over the age of 40. The 5,858 GBS isolates exhibited notably high resistance rates to erythromycin (72.2%), clindamycin (60%), and levofloxacin (50.1%), with 30.8% classified as multidrug-resistant. Importantly, invasive GBS strains exhibited a higher resistance rate to levofloxacin (61.2%) compared to colonizing strains (49.8%). This study highlights the importance of continuous screening and monitoring for GBS, especially given the concerning antibiotic resistance rates of GBS.IMPORTANCEGroup B Streptococcus (GBS) is an important pathogen that commonly causes infections in newborns and the elderly. This retrospective study provides a comprehensive analysis of GBS strains isolated from a large tertiary hospital in Beijing between 2013 and 2023, revealing an increasing colonization rate of GBS in both pregnant and non-pregnant women. Analysis of vaginal pathogens indicates a growing proportion of GBS among vaginal pathogens. Additionally, the high resistance rates of GBS to erythromycin, clindamycin, and levofloxacin, as well as the prevalence of multidrug resistance, are issues that merit attention. We also examined the differences in resistance rates of GBS strains from various sample types, finding that the levofloxacin resistance rate in GBS strains causing invasive infections was significantly higher than in colonizing strains. This study provides new data and insights for clinical research on GBS.

Bacterial Etiology of Lower Respiratory Tract Infection that Isolated from Tripoli University Hospital (TUH) Units in 2019

Introduction: Lower respiratory tract infection (LRTI) is one of the common major health problems, causing morbidity and mortality. Aims: The study was conducted to determine the current trends of bacterial etiology of LRTIs among patients who attended the University Teaching Hospital (UTH) and their antimicrobial susceptibility profile with special interest on drug resistance. Study Design: The study was a Cross sectional study. All patients’ files were selected as diagnosed with LRTIs and their demographic data, other illness, prescribed treatment /antibiotic used previously. Place and Duration of Study: This study is designed to collect data from files of lower respiratory tract infection patients following in units of university hospital in Tripoli. Methodology: The study was conducted between January to December 2019. at the unit in university hospital in Tripoli city in Libya. Sputum samples of 465 patients with suspected LRTIs were received, after obtaining patients' informed consent and ethical clearance from the UNTH. The samples were collected and processed according to standard laboratory procedures. Results: Of the total 465 sputum samples, 366 (78.7%) were positive for micro-organisms. Four main types of bacteria have been identified: acinetobacter spp. 25.6%, Klebsiellla pneumoniae 25.6%, P. saeroginosa (1.39%), Candida (9.03%). The distribution of lower respiratory tract infections within the hospital department indicated that the isolated strains revealed a higher infection rate of Gram-negative bacteria in the Pediatric Intensive Care Unit (PICU) and General Surgical Intensive Care Unit (GSICU) compared to other departments, with statistical significance. Notably, there was a significant difference in the infection rates of Pseudomonas in the Special Care Baby Unit (SCBU) with 7 cases, and in the Medical Intensive Care Unit (MICU) with 6 cases, as well as in the Neonatal Intensive Care Unit (NICU) with 2 cases. The infection rates for Candida and Streptococcus pneumoniae in the NICU were recorded at 2, 1, and 2, respectively, which were significantly different from those observed in other departments. The prevalence of antimicrobial resistance among Gram-negative and Gram-positive bacterial isolates indicated a very high resistance rate (98–100%) among Acinetobacter baumannii isolates to various antibiotics including AK, AMC, ATM, CAZ, CRO, CIP, GN, MEM, TOB, PRL, and CZ. However, for SXT, the isolate demonstrated the highest sensitivity, with a resistance rate of less than 53%. Conclusion: Understanding the variety of pathogens that cause lower respiratory tract infections (LRTIs) and their patterns of susceptibility to antibiotics, in addition to monitoring antibiotic resistance, is crucial for the effective management of LRTIs. This includes timely clinical and laboratory diagnoses, as well as the implementation of the appropriate treatment strategies.

Antimicrobial Susceptibility Trends in E. coli Causing Pediatric Urinary Tract Infections in the United States

Urinary tract infections (UTIs) are among the most common pediatric infections. This study evaluated the antimicrobial susceptibility patterns of 3511 uropathogenic E. coli (UPEC) isolated from pediatric patients in the United States from 2014 to 2023. The database from the SENTRY antimicrobial surveillance program from 89 medical centers was utilized as a data source. The antimicrobial susceptibility was tested using the microbroth dilution technique against 24 antimicrobial agents. MICs were determined using the CLSI/EUCAST/FDA breakpoint criteria. All the antimicrobials reported susceptibility rates above 80% except for tetracycline (76.2%), trimethoprim–sulfamethoxazole (69.7%), and ampicillin–sulbactam (55.7%). During the study period, the susceptibility rates remained stable for most antimicrobial agents. However, significant differences were observed among age, gender, and U.S. census regions, with the Middle Atlantic showing the lowest and the Mountain region the highest susceptibility rates, for most antimicrobials. The incidence of ESBL UPEC increased from 7.1% to 10.8% between 2014 and 2023, while the prevalence of the MDR phenotype remained relatively stable. The prevalence of both ESBL and MDR phenotypes was highest among infants and young children (0–24 months), with the highest resistance rates from the Pacific region. Knowledge of the landscape of antibiotic resistance in pediatric UPEC will help healthcare providers to better tailor empiric treatment regimens for most UTI infections.

Synthesis and Antibacterial Activity of New 6″-Modified Tobramycin Derivatives

Objectives: Aminoglycosides are one of the first classes of natural antibiotics which have not lost relevance due to their broad spectrum of action against Gram-positive, Gram-negative bacteria and mycobacteria. The high growth rate of antimicrobial resistance (AMR) together with the severe side effects of aminoglycosides increase the importance of developing improved semisynthetic derivatives. Methods: In this work, we proposed a synthetic route to new tobramycin derivatives modified at the 6″-position with aminoalkylamine or guanidinoalkylamine residues. Results: The antibacterial activity of the new compounds against reference strains of microorganisms was comparable to the parental tobramycin. In striking contrast to tobramycin (resistance index, >256), its 6″-modified derivatives were significantly more potent against resistant clinical isolates of P. aeruginosa strains (resistance index = 4–16) and they demonstrated a promising AMR circumvention in E. coli strains associated with mutations in the fusA gene encoding elongation factor G. All the obtained tobramycin derivatives exhibited reduced cytotoxicity for the eukaryotic HEK293T cells compared to the tobramycin and thereby they potentially may have improved therapeutic index. The proposed modification of the 6″-position of tobramycin does not change the mechanism of aminoglycoside’s antibacterial activity: new compounds induced translation errors which resulted in the inhibition of protein synthesis in bacterial cells. Conclusions: Taken together, we can suggest that further modifications of the 6″-position of tobramycin may be beneficial for circumvention of AMR to aminoglycosides or used for conjugation with other molecules of interest.

High prevalence of CTX-M-15 producing Shigella spp. isolated from patients with gastroenteritis in Northeast Iran.

Shigellosis, a diarrheal disease caused by Shigella species, is a significant public health concern, particularly in developing countries with inadequate sanitation systems. This study aimed to investigate the patterns of antibiotic resistance, ESBL and AmpC genes, integrons, and enterotoxin genes in Shigella species isolated from patients with gastroenteritis in Northeast Iran. This cross-sectional study was conducted between January 2017 and December 2019 at a tertiary care hospital in Northeast Iran. Atotal of 110 Shigella isolates were collected from stool samples of patients with gastroenteritis. The isolates were identified using conventional biochemical tests and confirmed by PCR. The highest resistance rates were detected for ampicillin (88.2%) and cotrimoxazole (84.5%). Altogether 64.5% of isolates exhibited multidrug resistance however, ESBL and AmpC phenotypes were detected in 34.54% and 1.81% of isolates, respectively. Interestingly, blaCTX-M-15 and blaTEM were detected in all ESBL-positive isolates but integron class 1, 2, and 3 were identified in 97.3%, 76.4%, and 59.1% of isolates, respectively. The sen gene was present in 72.7% of the isolates. In this study CTX-M-15 production was detected in 31 strains of Shigella sonnei and in 7 strains of Shigella flexneri. The high prevalence of multidrug-resistant Shigella isolates is concerning and shows the need for continuous monitoring and rational use of antibiotics.

Antibiotic resistance of bioaerosols in particulate matter from indoor environments of the hospitals in Dhaka Bangladesh

The emergence and spread of antibiotic resistance in microorganisms pose significant challenges to public health, especially in hospitals. This study investigated the existence or occurrence of bacterial bioaerosol and their antibiotic resistance patterns in particulate matter (PM) collected from hospitals in the greater Dhaka region, Bangladesh. The real-time particulate matter concentrations (PM1.0, PM2.5, and PM10) were measured in four hospitals and two ambient locations. Air sampling was conducted using a filter-based method with a low-volume air sampler, while AEROCET-531 S (USA) was employed to monitor particulate matter concentrations. Bacterial bioaerosol concentration was determined using a culture-based method, and eleven bacterial species, including nine individual species, i.e., Staphylococcus aureus, Pseudomonas aeruginosa, P. stutzeri, Bacillus cereus, Acinetobacter schindleri, Proteus vulgaris, B. subtilis, Escherichia coli, and B. aerius, were isolated. Antibiotic susceptibility testing was conducted using the Kirby-Bauer disk diffusion method with 21 antibiotics. Bacterial isolates were detected using partial sequencing of the 16 S rRNA gene. Bioaerosol concentration ranged from 194.65 ± 22.48 CFU/m3 to 948.39 ± 84.14 CFU/m3, showing significant correlations with PM1.0 and PM2.5 concentrations (R2 = 0.80 and 0.85, respectively). All bacterial isolates collected from the hospitals exhibited resistance against four or more antibiotics, indicating multidrug resistance (MDR). Notably, the bacterial isolates displayed the highest resistance rate against ampicillin (90.90%), azithromycin (81.81%), erythromycin (81.81%), cefixime (81.81%), and cotrimoxazole (54.54%), among the tested antibiotics. Except B. aerius, all other bacterial isolates were associated with hospital-acquired infections (HAIs). These findings highlight the high rates of antibiotic resistance, underscoring the pressing requirement for infection control measures and continuous surveillance strategies in hospital settings. These findings emphasize the necessity for global hospital infection control strategies focusing airborne multidrug-resistant microorganisms.

High antimicrobial resistance rates and multidrug resistance in Enterobacteriaceae isolates from poultry in Souk Ahras region, Algeria

Background and Aim: The spread of antimicrobial resistance (AMR) in the Enterobacteriaceae family represents a major global health problem for humans and animals. This study aimed to determine AMR levels and highlight the different resistance profiles of Enterobacteriaceae isolates collected from healthy broiler chickens in eastern Algeria. Materials and Methods: A total of 200 cloacal swabs of healthy broilers from several poultry farms located in the Souk Ahras region (eastern Algeria) were collected. Samples were inoculated on MacConkey agar, and the isolated bacteria were identified using the API 20E system. Antimicrobial susceptibility testing was conducted using the disk diffusion method in accordance with the Clinical and Laboratory Standards Institute guidelines. The broth microdilution method was used to determine the minimum inhibitory concentration of colistin (CT). Results: Two hundred and forty-one isolates of commensal Enterobacteriaceae were recovered, including: Escherichia coli (n = 194; 80.5%), Proteus mirabilis (n = 21; 8.71%), Escherichia fergusonii (n = 8, 3.32%), Salmonella spp. (n = 7, 2.9%), Enterobacter cloacae (n = 4, 1.66%), Klebsiella pneumoniae (n = 3, 1.25%), Serratia spp. (n = 3, 1.25%), and Kluyvera spp. (n = 1, 0.41%). High resistance rates were observed toward erythromycin (100%), doxycycline (96.68%), trimethoprim-sulfamethoxazole (95.85%), ciprofloxacin (94.19%), ampicillin (90.04%), kanamycin (78.01%), and amoxicillin-clavulanic acid (69.71%). However, moderate-to-low resistance rates were observed for CT (25.31%), ceftazidime (12.45%), and cefotaxime (8.71%). Interestingly, only two extended-spectrum beta-lactamase (ESBL)-producing E. coli isolates were detected. All isolates (100%) were multidrug-resistant (MDR), among which 58.92% were resistant to six and seven antibiotics. Forty AMR profiles were identified, reflecting a wide diversity of resistance with combinations of three to ten antibiotics. Conclusion: Our findings revealed alarming rates of AMR, highlighting the need to take measures to combat the phenomenon of AMR to protect animals and public health. Keywords: Algeria, antibiotic resistance, Enterobacteriaceae, multidrug resistance, poultry.

Genomic and phenotypic characterization of ST2012 clinical Klebsiella quasipneumoniae subsp. similipneumoniae harboring blaNDM−1 in China

BackgroundKlebsiella pneumoniae has emerged as a significant pathogen that causes community and hospital infections due to its high resistance rate and transmissibility. Klebsiella pneumoniae complex is classified into three phylogroups: Klebsiella pneumoniae (KpI), Klebsiella quasipneumoniae (KpII), and Klebsiella variicola (KpIII) in classical taxonomy, but KpII and KpIII are infrequently isolated clinically. Although pathogenic KpII has been reported worldwide, the understanding of this pathogen remains limited.MethodsWhole-genome sequencing (WGS) of K. quasipneumoniae subsp. similipneumoniae ACESH00366hy was performed. Plasmid characterization was demonstrated using S1-PFGE, Southern blotting, and conjugation assays. Antimicrobial susceptibility testing was performed and interpreted according to CLSI, EUCAST, and FDA standards. The virulence of the strain was assessed using the Galleria mellonella infection assay, serum-killing assay, and biofilm formation assay. A phylogenetic tree was constructed to explore its biological evolution.ResultsThe K. quasipneumoniae subsp. similipneumoniae isolate ACESH00366hy, belonging to ST2012 and KL139, contains several resistance genes including blaNDM−1, blaSHV−12, blaOKP−B−2, and oqxAB, as well as various virulence genes including iroE, iutA, mrkABCDFHIJ, entABCDEFS, and fepABCDG. The blaNDM−1 and blaSHV−12 genes were present on the 53,624 bp IncX3 plasmid. Virulence assays showed that the virulence of ACESH00366hy was greater than that of the low-toxicity strain ATCC 700,603. Phylogenetic analysis demonstrated the emergence of ST2012 KpII-B in Asia and revealed the spread of K. quasipneumoniae subsp. similipneumoniae in humans, animals, and the environment.ConclusionThis study highlights the emergence of clinical ST2012 KpII strains harbouring blaNDM−1 via the IncX3 plasmid in China. We evaluated its resistance and virulence characteristics and performed phylogenetic analysis, thereby enhancing our understanding of its resistance and pathogenicity and contributing to the clinical surveillance of K. quasipneumoniae.

Patterns of Antimicrobial Resistance in Urinary Tract Infection Pathogens: Analysis in a Provincial Hospital in Zimbabwe

Introduction. Urinary tract infections (UTIs) are among the most common infections globally. Rising multidrug-resistant uropathogens in Zimbabwe underscore the need to review their susceptibility profiles. This study examines antimicrobial susceptibility trends of uropathogens in patients from Victoria Chitepo Provincial Hospital. Methods: This retrospective study included 385 randomly selected UTI-positive patients from 2023. Midstream, clean-catch urine samples were processed using standard microbiological techniques, and statistical analysis was conducted. Results: More females (56.4%) than males (43.6%) had UTIs, with age groups 0–9 and 20–29 years most affected (16.6% each). The predominant uropathogens were E. coli (27.2%), K. pneumoniae (18.4%), Staphylococcus spp. (17.4%), and Enterobacter spp. (12.2%). E. coli was most susceptible to ceftriaxone (93%) and most resistant to doxycycline; K. pneumoniae was most susceptible to chloramphenicol (70.4%). Conclusion: E. coli was the most common uropathogen. Most uropathogens showed susceptibility to ceftriaxone, gentamicin, and chloramphenicol. However, Staphylococcus spp. displayed resistance to norfloxacin, ciprofloxacin, nalidixic acid, and doxycycline. The high resistance rates highlight the need for antimicrobial stewardship and confirmatory testing before prescribing.

Unveiling the Dynamics of Antimicrobial Resistance: A Year-Long Surveillance (2023) at the Largest Infectious Disease Profile Hospital in Western Romania

Background/Objectives: Antimicrobial resistance (AMR) is a critical global health threat, leading to increased morbidity, mortality, and healthcare costs. This study aimed to identify the most common bacterial pathogens and their resistance profiles from 2179 positive clinical cultures from inpatients at “Victor Babes” Hospital of Infectious Disease and Pneumoftiziology Timisoara in 2023. Methods: Samples were collected from sputum, bronchial aspiration, hemoculture, urine, wound secretions, catheter samples, and other clinical specimens. Results: Key pathogens identified included Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii, with notable resistance patterns, observed K. pneumoniae exhibited high resistance rates, notably 41.41% in Quarter 1, while E. coli showed 35.93% resistance in the same period. S. aureus, particularly MRSA, remained a persistent challenge, with 169 cases recorded over the year. A. baumannii and P. aeruginosa displayed alarming levels of multi-drug resistance, especially in Quarter 3 (88.24% and 22.02%, respectively). Although there was a general decline in resistance rates by Quarter 4, critical pathogens such as S. aureus and K. pneumoniae continued to exhibit significant resistance (81.25% and 21.74%, respectively). Conclusions: The study’s findings align with the broader antimicrobial resistance trends observed in Romania, where high resistance rates in K. pneumoniae, E. coli, S. aureus (MRSA), Acinetobacter, and Pseudomonas species have been widely reported, reflecting the country’s ongoing struggle with multi-drug-resistant infections. Despite some reductions in resistance rates across quarters, the persistent presence of these resistant strains underscores the critical need for strengthened antimicrobial stewardship, infection control measures, and continuous surveillance to combat the growing threat of AMR in Romania and similar healthcare settings.

Cytokines Levels and Anti-tuberculosis Drug Resistance among HIV Seropositive Patients in Ibadan, Southwest, Nigeria

Susceptibility to TB disease rises on mutations in cytokine receptors which ultimately lead to defective signaling and alter the immune surveillance and bacterial killing. Therefore, this study was undertaken to investigate the association between cytokines and anti-TB drug resistances. A total of 217 people living with human immunodeficiency virus at University College Hospital, Ibadan were recruited. Venous blood and sputum samples were collected. Sputum samples were cultured for Mycobacterium tuberculosis complex and characterized using standard methods. Anti-TB drug resistance was detected using phenotypic and genotypic methods. Cytokines levels (IL-10 and IFN-Y) were estimated using ELISA method. Association between cytokines and anti-TB drug resistance was determined using linear regression analysis. There were 105(48.4%) males and 112(51.6%) females with a mean age of 42.95 ± 8.286 years and a range of 28-65 years. The prevalence of TB among PLHIV was found to be 19.1% with male having higher rate than female (P<0.05), and highest rate among aged ≥40. There was no significant association between cytokines (IL-10 and IFN-y) and sex of the subjects (P>0.05). However, females had higher IFN-y level of 231.06±61.81 IU/ml when compared to 227.53±57.92 IU/ml obtained from males. The prevalence of multi-drug resistance TB was 11.9% with Rifampicin resistance having the highest rate of 5.5%. There was no significant association between cytokines (IL-10 and IFN-y) and sex, but age group >40 years had higher IL-10 and IFN-y level of 226.53±52.39 IU/ml and 232.41±66.63 IU/ml respectively. There was an association between high cytokines levels and anti-TB drug resistance (P<0.05). Highest cytokines levels; IL-10 (401.00±7.07 IU/ml) and IFN-Y (401.00±7.07 IU/ml) were recorded in Levofloxacin resistance. There was an association between high cytokines levels and genotypic anti- TB drug resistance (P<0.05) with highest cytokines levels; IL-10 (400.12±12.37 IU/ml) and IFN-Y (472.87±31.93 IU/ml) recorded in Rifampicin resistance. This entire study revealed that there is high prevalence of MDR-TB among PLHIV, with Rifampicin monoresistance having the highest resistance rate among the drugs tested, and pro and inflammatory cytokines (IL-10 and IFN-y) play significant role in the development of Multi Drug Resistant-Tuberculosis among people living with HIV.

Fabrication of Water-Based Alcoholized Poly(butylene succinate-co-adipate) Submicron Particles as Green Coating Agents for Sustainable Paper Packaging.

This work aims to fabricate the water-based suspension of poly(butylene succinate-co-adipate) (PBSA) particles by an oil-in-water emulsion technique for use as coating agents to enhance paper-based packaging performances and sustainability. A commercial PBSA resin is functionalized by sizing down an approach via microwave-assisted alcoholysis using propylene glycol (PG). The effect of PBSA/PG feed ratio on the structures, properties, and particle formability of the alcoholized (aPBSA) products is examined. 1H NMR results reveal that the average molecular weight of the aPBSA product decreases to half that of neat PBSA when using a ratio of 24:1 and further decreases to a quarter at 6:1. By using small-size aPBSA, the obtained water-based particles show high stability due to high hydroxyl content and poly(vinyl alcohol) assistance. The suspension is then sprayed on a kraft paper substrate and heated at 60 and 100 °C. SEM results reveal that the submicron aPBSA particles penetrate the paper matrix, filling the paper's pores and forming a protective, smooth layer on the paper surfaces. The coated paper shows high water resistance (Cobb60 value of 19.6 g/m2) and water vapor transmission rate (1160 g/(m2 day)). In addition, the aPBSA-coated layers do not impede the paper's repulping and recycling processes, making it a promising solution for improving the sustainability of paper-based packaging.

Etiology and antimicrobial resistance of subclinical mastitis pathogens Staphylococcus aureus, Streptococcus spp. and Enterococcus spp. in sheep milk.

The present study investigates the prevalence and etiology of subclinical mastitis in Țurcana sheep flocks located in south-western Romania. Milchtest and California Mastitis Test (CMT), were used for the detection of subclinical mastitis. A number of 360 milk samples across three lactation phases were analyzed. Subclinical mastitis was identified in 146 (40.6%) of sheep milk samples. Only milk samples (n = 146) collected from sheep diagnosed with subclinical mastitis were considered for microbiological analyses. Thus, Staphylococcus aureus (129/146; 88.4%) was identified as the predominant pathogen followed by Streptococcus spp. (14/146; 9.6%) Enterococcus spp. (7/146; 4.8%), Pseudomonas aeruginosa (6/146; 4.1%) and Klebsiella pneumoniae (5/146; 3.4%). Antimicrobial susceptibility of isolated strains of Staphylococcus aureus, Streptococcus spp. and Enterococcus spp. was also tested. The results showed varying resistance patterns depending on the farm and microorganism. In heard A the highest resistance of Staphylococcus aureus was identified to polymyxin B (79.7%) followed by novobiocin (73.4%) and tetracycline (45.3%); Streptococcus spp. to streptomycin (100%), novobiocin (100%), tetracycline (100%) and Enterococcus spp. to tylosin (100%), streptomycin (75.0%) and tetracycline (75.0%). In herd B, Staphylococcus aureus showed high resistance rates to polymyxin B (86.3%), novobiocin (74.5%) and cloxacillin (39.2%); Streptococcus spp. strains to streptomycin (100%), novobiocin (100%), tetracycline (100%) and Enterococcus spp. to gentamicin (100%), streptomycin (66.7%) and erythromycin (66.7%). The obtained preliminary results indicate a potential risk that future treatments of sheep mastitis may not be effective, and demonstrated that raw unpasteurized milk can harbor antimicrobial resistance pathogens posing a threat to public health. However, further investigations involving molecular research on resistance genes are required to draw comprehensive conclusions.

Molecular characterization of Klebsiella pneumoniae in clinical bovine mastitis in 14 provinces in China.

The mastitis caused by Klebsiella pneumoniae (K. pneumoniae) is increasing in the dairy cows. To investigate the epidemic of K. pneumoniae of China, 131 strains were isolated from 495 clinical mastitis milk samples (26.5%) from 14 provinces in China. Among the isolates, K57 was the dominant serotype (45.0%) and 19 (14.5%) isolates were identified as hypervirulent K. pneumoniae (hvKP). The mrkA, entB, wabG and fimH genes were prevalent virulence genes while rmpA, magA, and ycf were not found in K. pneumoniae. Furthermore, K. pneumoniae had serious antibiotic resistance and multiple β-lactamase genes, including blaTEM, blaSHV, blaNDM, blaCTX-M, blaDHA, and blaKPC. Biofilm was an important factor in bacterial resistance and persistent infection, and 77.1% isolates could form biofilm. Although acylated homoserine lactone (AHL, a Gram-negative bacterial quorum sensing signal molecule) was not confirmed among the K. pneumoniae isolates, exogenous AHLs could reduce the biofilm formation ability of the K. pneumoniae strains. Three new ST types (ST6781, ST6782, and ST6783) were first identified in this study. The MLST phylogenetic tree showed the distribution of mastitis associated K. pneumoniae strains had no regular pattern, which confirmed high genomic diversity of mastitis associated K. pneumoniae. In conclusion, the high rate of isolation and serious antibiotic resistance of K. pneumonia were found in this study and indicated a potential threat to public health from the food chain.

Comparative efficacy of Helicobacter pylori eradication therapy between tegoprazan-based concomitant and bismuth quadruple therapies: A real-world evidence.

Tegoprazan, a potassium-competitive acid blocker, can be used as a substitute for proton pump inhibitors in Helicobacter pylori eradication therapy; some studies have reported improved efficacy. In Korea, where clarithromycin resistance rates are high, we aimed to compare the efficacies of tegoprazan-based concomitant and bismuth quadruple therapies. We retrospectively analyzed data from patients with H.pylori infection who received either 10-day tegoprazan-based concomitant therapy or 14-day tegoprazan-based bismuth quadruple therapy as first-line treatment. The primary outcome was H.pylori eradication rate, with secondary outcomes including adverse events and insufficient medication rates. Among the 1082 patients included in the study, 620 and 462 were treated with tegoprazan-based concomitant and bismuth quadruple therapies, respectively. Intention-to-treat analysis demonstrated no difference in eradication rates between the tegoprazan-based concomitant and bismuth quadruple therapy groups (74.7% [95% confidence interval-CI, 71.1-78.0%] vs 74.7% [95% CI, 70.6-78.5%], P=0.999). Per-protocol analysis also showed similar eradication rates between the two groups (88.0% [95% CI, 85.0-90.6%] vs 89.7% [95% CI, 86.3-92.5%], P=0.424). The overall adverse event rates (49.6% vs 39.2%, P=0.001) and insufficient medication rates (4.8% vs 2.4%, P=0.036) were higher in the bismuth quadruple therapy group than in the concomitant therapy group. The eradication rates of tegoprazan-based 10-day concomitant therapy and 14-day bismuth quadruple therapy were comparable. However, because of its shorter treatment duration, better medical adherence, and lower incidence of adverse events, tegoprazan-based concomitant therapy may be preferable in regions with high rates of clarithromycin and metronidazole resistance.

Nasal Carriage of Antimicrobial-Resistant Staphylococci by Fallow Deer (Dama dama) Taken in a Natural Park of Tuscany, Central Italy.

Wild animals are recognized as significant reservoirs for various zoonotic pathogens, including antibiotic-resistant bacteria. This study aimed to investigate the presence of Staphylococcus spp. strains in fallow deer (Dama dama) inhabiting a natural preserve in Central Italy and to examine the phenotypic and genotypic antimicrobial resistance and the presence of some virulence genes among the isolates. During July and December 2022, nasal swabs were collected from 175 fallow deer, which were then analyzed through bacteriological cultures. In total, 176 Staphylococcus spp. strains were isolated and subsequently identified using MALDI-TOF mass spectrometry. S. aureus was the most abundant species with 66 (37.5%) strains, followed by S. hyicus, 34 (19.31%) strains, S. sciuri, 32 (18.18%) strains, S. chromogenes, 27 (15.34%) strains, S. xylosus, 11 (6.25%) strains, S. warneri, 5 (2.84%) strains, and S. devriesei, 1 (0.56%) strain. Antimicrobial susceptibility was assessed for each isolate via the agar disk diffusion method, testing a panel of 13 molecules belonging to 9 antimicrobial classes. The highest resistance rates were detected for penicillin (29.55%), rifampicin (22.73%), and amikacin (20.45%). Notably, intermediate susceptibility was observed for erythromycin (61.93%), enrofloxacin (28.41%), and ceftiofur (21.02%). Conversely, the strains exhibited particularly high susceptibility to amoxicillin/clavulanic acid (99.43%), cefoxitin (97.73%), and vancomycin (96.02%). Based on the results, 32 (18.18%) isolates were classified as multidrug-resistant (MDR). Two strains of S. chromogenes and one strain of S. xylosus, both resistant to penicillin, tested positive for the blaZ gene. No methicillin-resistant strains were found, and none of the isolates harbored genes associated with enterotoxin and toxic shock syndrome toxin production. This study highlights the potential role of wildlife, particularly fallow deer, as reservoirs of antibiotic-resistant Staphylococcus spp. strains. Such findings underscore the importance of monitoring wildlife for antimicrobial resistance, which could have implications for public health and veterinary medicine.

Antibiotic Resistance in Mycobacterium Tuberculosis and Non-Tuberculous Mycobacteria

Mycobacterium tuberculosis (MTB) and non-tuberculous mycobacteria (NTM) antibiotic resistance presents an important challenge to the treatment of mycobacterial infections. The therapeutic approaches are complicated by the resistance of both MTB and NTM to a variety of antibiotics. Resistance to first-line drugs such as isoniazid, rifampicin, ethambutol, and streptomycin has been consistently increasing in MTB, underscoring the necessity of effective treatment strategies. Conversely, the necessity of species-specific treatment regimens is underscored by the high resistance rates of NTM species, such as Mycobacterium avium complex, M. kansasii, and M. abscessus complex, to commonly used anti-tuberculosis pharmaceuticals. A combination of intrinsic and acquired factors are involved in the mechanisms of antibiotic resistance in these mycobacteria. Features such as biofilm formation, thick cell walls, and reduced drug uptake are responsible for intrinsic resistance in NTM, whereas acquired resistance can develop as a result of protracted antibiotic exposure. Understanding these resistance mechanisms is essential for the development of new therapies and the prevention of the increasing prevalence of drug resistance in mycobacterial infections. The significance of continuous surveillance, species-specific treatment protocols, and the development of novel antimicrobial agents to effectively manage mycobacterial diseases is emphasized by the prevalence of antibiotic resistance in MTB and NTM. This review article focuses on the molecular mechanisms that have resulted in the development of resistance in both MTB and NTMs, as well as the extent to which various classes of antimycobacterial drugs act.

A multidimensional assessment of in-host fitness costs of drug resistance in the opportunistic fungal pathogen Candida glabrata.

Drug-resistant microbes typically carry mutations in genes involved in critical cellular functions and may therefore be less fit under drug-free conditions than susceptible strains. Candida glabrata is a prevalent opportunistic yeast pathogen with a high rate of fluconazole resistance (FLZR), echinocandin resistance (ECR), and multidrug resistance (MDR) relative to other Candida. However, the fitness of C. glabrata MDR isolates, particularly in the host, is poorly characterized, and studies of FLZR isolate fitness have produced contradictory findings. Two important host niches for C. glabrata are macrophages, in which it survives and proliferates, and the gut. Herein we used a collection of clinical and lab-derived C. glabrata isolates to show that FLZR C. glabrata isolates are less fit inside macrophages than susceptible isolates and that this fitness cost is reversed by acquiring ECR mutations. Interestingly, dual-RNAseq revealed that macrophages infected with drug-resistant isolates mount an inflammatory response whereas intracellular drug-resistant cells downregulate processes required for in-host adaptation. Furthermore, drug-resistant isolates were outcompeted by their susceptible counterparts during gut colonization and in infected kidneys, while showing comparable fitness in the spleen. Collectively, our study shows that macrophage-rich organs, such as the spleen, favor the retention of MDR isolates of C. glabrata.

Prevalence and antimicrobial susceptibility profile of uropathogens in dogs and cats with signs of urinary tract infection.

To determine the prevalence of uropathogens in dogs and cats with signs of urinary tract infection and to characterise their antimicrobial susceptibility. Urine samples from canine and feline patients with clinical signs of urinary tract infection were collected between September 2015 and December 2019 in Santiago, Chile. Bacterial identification and bacterial susceptibility profile was performed through biochemical and antimicrobial susceptibility tests. Four hundred sixty-six samples from dogs (37.7%) and 152 from cats (26.1%) showed bacterial growth. Positive samples were mainly from females (dogs: 52.8%; cats: 48.0%), with the highest infection rates in senior dogs (57.7%) and adult cats (45.4%). A single organism caused the infection in 78.2% of the cases, whereas the remaining 21.8% corresponded to a mixed infection. The most prevalent isolated pathogen in dogs and cats was Escherichia coli (42.6% and 49.7%, respectively). Staphylococcus spp. (15.6% and 14.6%), Enterococcus spp. (8.6% and 15.2%) and Proteus spp. (9.7% and 6.4%) were also commonly isolated. A total of 52.4% of Escherichia coli isolates were resistant to amoxicillin, 44.3% to amoxicillin/clavulanic acid, 40.0% to cephradine and 25.3% to ciprofloxacin. Regarding the other three uropathogens commonly isolated in this study, all of them showed a percentage of resistance to the antimicrobials analysed. In addition, 24.6% of multidrug resistance was detected in the E. coli isolates. Penicillin, cephalosporins and fluoroquinolones showed the lowest susceptibility levels. The observed high rates of resistance to commonly prescribed antimicrobials raise concerns for public health.

Extended-Spectrum Beta-Lactamase-Producing and Multidrug-Resistant Escherichia coli and Klebsiella spp. from the Human–Animal–Environment Interface on Cattle Farms in Burkina Faso

Extended-spectrum beta-lactamase (ESBL)-producing and multidrug-resistant Enterobacterales pose a major threat to both human and animal health. This study assessed the prevalence of ESBL-producing Escherichia coli (ESBL-Ec) and Klebsiella spp. (ESBL-K) on cattle farms in Ouagadougou, Burkina Faso, using a One Health approach. From May 2021 to September 2022, cattle faeces, farmers’ stools, their drinking water and farm soil samples were collected from semi-intensive and traditional farms. An ESBL-selective medium was used to obtain resistant isolates, which were further characterised using biochemical tests. Antimicrobial susceptibility testing was performed using the Kirby–Bauer disc diffusion method. ESBL-Ec and/or ESBL-K were detected in 188 of 322 samples (58.0%). The prevalence of ESBL-Ec isolates was 42.2% (136/322) and that of ESBL-K isolates was 24.5% (79/322). Notably, 156 of the 188 ESBL isolates (83.0%) exhibited multidrug resistance. The highest resistance rates were observed against tetracycline and cotrimoxazole. Importantly, no isolates showed resistance to meropenem, which was used to test for carbapenem resistance. This study highlights the presence of ESBL-Ec and ESBL-K among the humans, animals and environment of the cattle farms. Good hygiene and biosafety practices are essential to limit the potential spread of multidrug-resistant bacteria between different interfaces on farms.