Simple and sensitive detection of Pseudomonas aeruginosa in neonatal infection based on a both-end blocked peroxidase-mimicking DNAzyme.

Developing a simple and highly sensitive approach for Pseudomonas aeruginosa (P. aeruginosa) detection is crucial, as it is closely associated with various disorders, such as newborn infections. Nevertheless, few of techniques have the capability to accurately identify P. aeruginosa with a high level of sensitivity and significantly improved stability. The employment of the both-end blocked peroxidase-mimicking DNAzyme significantly diminished the interferences from background signals, so conferring the approach with a high degree of selectivity and reproducibility. The proposed method is demonstrated with exceptional discernment capacity in differentiating interfering microorganisms. The simplicity, elevated sensitivity and high discerning capability make the method a highly promising alternative instrument for pathogenic bacteria detection.

This research presents a novel method for detecting P. aeruginosa using a combination of a simple molecular beacon (MB), duplex-specific nuclease (DSN), and both-end blocked peroxidase-mimicking DNAzyme. The MB probe utilized in this method can be shielded from DSN hydrolysis without requiring any additional modifications by regulating the number of stem bases to five. This assay is simple yet precise in its ability to quantitatively detect P. aeruginosa with a high level of sensitivity and specificity. In addition, the beacon enabled the identification of P. aeruginosa without the need for labeling, exhibiting a higher sensitivity over the conventional hairpin fluorescence beacon based methods.

Malignant Otitis Externa: A persistent challenge.

INTRODUCTION: Although rare, Malignant otitis externa is responsible for a high morbidity and could sometimes be fatal. The management of this condition is still challenging. AIM: To analyse the clinical, microbiological and radiological profile of malignant otitis externa, and the management of this condition. METHODS: A descriptive, cross-sectional study was conducted at ENT Department of Kairouan's hospital including 38 patients hospitalised and treated for malignant otitis externa from January 2013 to August 2021. RESULTS: The mean age of patients was 67.7 ± 12.9 years (35-98). All patients presented with continuous otalgia that resists to usual analgesics. Otorrhea was noticed in 76.3% of cases, facial palsy in 2 cases (5.3%) and dysphonia in one case (2.6%). Pseudomonas Aeruginosa was the main responsible pathogen (42%). Concomitant bacterial and fungal infection was noticed in 6.4% of the cases. First-line intravenous antibiotherapy used was mainly based on an association of Cephalosporins and Fluoroquinolones. Complete remission was noticed in 30 patients (79%). However, 8 cases of recurrences (21%) and 2 cases of deaths (5.2%) were noticed in our series. The mean follow-up was 4.6±6.3 (1-26 months). CONCLUSIONS: Pseudomonas Aeruginosa remains the main responsible pathogen for malignant otitis externa. Nevertheless, fungal infections are rising because of the overuse of antibiotics. Antibiotherapy should be adapted to culture results and resistance profile of pathogens in hospital. Practionners should be aware of the possibility of concomitant fungal infection, especially in the case of unfavorable evolution.

Tracing the origin of NDM-1-producing and extensively drug-resistant Pseudomonas aeruginosa ST357 in the Netherlands.

BACKGROUND: In the hospital environment, carbapenemase-producing Pseudomonas aeruginosa (CPPA) may lead to fatal patient infections. However, the transmission routes of CPPA often remain unknown. Therefore, this case study aimed to trace the origin of CPPA ST357, which caused a hospital-acquired pneumonia in a repatriated critically ill patient suffering from Guillain-Barré Syndrome in 2023. METHODS: Antimicrobial susceptibility of the CPPA isolate for 30 single and combination therapies was determined by disk-diffusion, Etest or broth microdilution. Whole-genome sequencing was performed for three case CPPA isolates (one patient and two sinks) and four distinct CPPA ST357 patient isolates received in the Dutch CPPA surveillance program. Furthermore, 193 international P. aeruginosa ST357 assemblies were collected via three genome repositories and analyzed using whole-genome multi-locus sequence typing in combination with antimicrobial resistance gene (ARG) characterization. RESULTS: A Dutch patient who carried NDM-1-producing CPPA was transferred from Kenya to the Netherlands, with subsequent dissemination of CPPA isolates to the local sinks within a month after admission. The CPPA case isolates presented an extensively drug-resistant phenotype, with susceptibility only for colistin and cefiderocol-fosfomycin. Phylogenetic analysis showed considerable variation in allelic distances (mean = 150, max = 527 alleles) among the ST357 isolates from Asia (n = 92), Europe (n = 58), Africa (n = 21), America (n = 16), Oceania (n = 2) and unregistered regions (n = 4). However, the case isolates (n = 3) and additional Dutch patient surveillance program isolates (n = 2) were located in a sub-clade of isolates from Kenya (n = 17; varying 15-49 alleles), the United States (n = 7; 21-115 alleles) and other countries (n = 6; 14-121 alleles). This was consistent with previous hospitalization in Kenya of 2/3 Dutch patients. Additionally, over half of the isolates (20/35) in this sub-clade presented an identical resistome with 9/17 Kenyan, 5/5 Dutch, 4/7 United States and 2/6 other countries, which were characterized by the blaNDM-1, aph(3')-VI, ARR-3 and cmlA1 ARGs. CONCLUSION: This study presents an extensively-drug resistant subclone of NDM-producing P. aeruginosa ST357 with a unique resistome which was introduced to the Netherlands via repatriation of critically ill patients from Kenya. Therefore, the monitoring of repatriated patients for CPPA in conjunction with vigilance for the risk of environmental contamination is advisable to detect and prevent further dissemination.

Antimicrobial resistance profile of Pseudomonas aeruginosa clinical isolates from healthcare-associated infections in Ethiopia: A systematic review and meta-analysis.

BACKGROUND: Antimicrobial-resistant (AMR) bacterial infection is a significant global threat to the healthcare systems. Pseudomonas aeruginosa, the leading infectious agent in the healthcare setting is now one of the major threats due to AMR. A comprehensive understanding of the magnitude of AMR, particularly highly public health important pathogens such as P. aeruginosa, is necessary for the management of infections based on local information. OBJECTIVE: This systematic review and meta-analysis aimed to determine the country-wide AMR of P. aeruginosa. METHODS: Systematic searches were performed to retrieve articles from PubMed, Scopus, Web of Science, ScienceDirect electronic databases, Google Scholar search engine, and repository registrars from 2015 to 31st December 2023. Twenty-three studies that provided important data on AMR in P. aeruginosa were systematically reviewed and analyzed to determine the country-wide magnitude of P. aeruginosa AMR profile from healthcare-associated infections. AMR of P. aeruginosa to 10 different antibiotics were extracted separately into Microsoft Excel and analyzed using STATA 17.0. Cohen's kappa was computed to determine the agreement between reviewers, the Inverse of variance (I2) was used to evaluate heterogeneity across studies, and Egger's test to identify publication bias. A random effect model was used to determine the pooled resistance to each antibiotic. Subgroup analysis was performed by infection type and year of publication. RESULTS: This systematic review and meta-analysis revealed that the pooled prevalence of P. aeruginosa in clinical specimens associated with HAI was 4.38%(95%CI: 3.00-5.76). The pooled prevalence of AMR in P. aeruginosa for different antibiotics varies, ranging from 20.9% (95%CI: 6.2-35.8) for amikacin to 98.72% (95%CI: 96.39-101.4) for ceftriaxone. The pooled resistance was higher for ceftriaxone (98.72%), Trimethoprim-sulfamethoxazole (75.41), and amoxicillin-clavulanic acid (91.2). In contrast relatively lower AMR were observed for amikacin (20.9%) and meropenem (28.64%). The pooled multi-drug resistance (MDR) in P. aeruginosa was 80.5% (95%CI: 66.25-93.84). Upon subgroup analysis by infection types and year of publication, P. aeruginosa isolated from healthcare-associated infections exhibited higher resistance to ceftazidime (94.72%) compared to isolates from mixed types of healthcare-associated infections (70.84%) and surgical site infections (57.84%). Antimicrobial resistance in gentamicin was higher during the periods of 2018-2020 (73.96%), while comparatively lower during 2021-2023 (42.69%) and 2015-2017 (29.82%). CONCLUSIONS: Significantly high AMR and MDR were observed from this systematic review and meta-analysis. AMR obtained from this systematic review and meta-analysis urges the need for improved infection control, antimicrobial stewardship practices, and strengthened surveillance systems to control the spread of AMR and ensure effective treatment of P. aeruginosa infections. PROTOCOL REGISTRATION: This systematic review and meta-analysis was registered on PROSPERO (Registration ID: CRD42024518145).

[Distribution and Drug Resistance Characteristics of Pathogenic Bacteria in the Elderly Population in China in 2021]. / 2021å¹´ä¸­å›½è€å¹´äººç¾¤æ„ŸæŸ“ç— åŽŸèŒåˆ†å¸ƒå’Œè€è¯æ€§ç‰¹å¾.

Objective: To study the distribution and drug resistance characteristics of pathogenic bacteria in the elderly population of China by collecting and analyzing the standardized case data on the pathogens of infections in elderly patients, and to facilitate the establishment of a standardized layered surveillance system for pathogenic bacteria in China. Methods: We collected the case data of elderly patients (≥65 years old) from 62 sentinel hospitals across the country in 2021. Then, we statistically analyzed the data by patient age, their geographical region, the distribution of pathogenic bacteria, and the drug resistance characteristics of main pathogens. Results: A total of 3468 cases from across the country were included in the study. The top three sources of patients were the intensive care unit (13.2%), the department of respiratory medicine (11.2%), and the department of general surgery (8.4%). The top three types of specimens were urine (25.5%), sputum (20.6%), and blood (18.7%). A total of 3468 strains of pathogens were isolated, among which, 78.9% were gram-negative bacteria and 21.1% were gram-positive bacteria. The top five types of bacteria were Escherichia coli (20.9%), Klebsiella pneumoniae (18.3%), Pseudomonas aeruginosa (11.2%), Staphylococcus aureus (9.0%), and Acinetobacter baumannii (7.0%). The isolation rates of common important drug-resistant bacteria were 38.0% for methicillin-resistant Staphylococcus aureus (MRSA), 68.7% for carbapenem-resistant Acinetobacter baumannii (CRAB), and 38.2% for carbapenem-resistant Pseudomonas aeruginosa (CRPA), 20.1% for carbapenem-resistant Klebsiella pneumoniae (CRKP), 5.2% for carbapenem-resistant Escherichia coli (CRECO), and 2.1% for vancomycin-resistant Enterococcus (VRE). There were differences in the isolation rates of CRAB and CRKP in clinical care in the elderly population in seven geographical regions of China (P<0.05). Klebsiella pneumoniae is the most important pathogen in the elderly population ≥85 years old, and the isolation rates of CRKP showed significant differences in different age groups (P<0.05). Conclusion: There are significant differences in the drug resistance of pathogenic bacteria in the elderly populations of different regions and age groups in China. Therefore, monitoring the distribution and drug resistance of pathogenic bacteria in the elderly population and formulating targeted treatment plans according to the characteristics of the specific regions and age groups are of great significance to the improvement in the treatment outcomes and prognosis of the elderly population.

Respiratory Pathogens at Exacerbation in Chronic Bronchitis With Airway Bacterial Colonisation: A Cohort Study.

BACKGROUND AND OBJECTIVE: COPD and bronchiectasis are common causes of morbidity, particularly around exacerbation. Colonisation with respiratory pathogens can increase the frequency and severity of exacerbations. However, bacterial and viral presence at exacerbation in people with airway colonisation has not been well studied. METHODS: A 6-month cohort study of participants (n = 30) with chronic bronchitis due to bronchiectasis (n = 26) and/or COPD (n = 13) and colonisation with Pseudomonas aeruginosa or Haemophilus influenzae was proven on two sputum cultures at exacerbation in the previous 12 months. Participants were provided self-management education and collected sputum samples daily. Sputum samples at baseline (at least 14 days before or after an exacerbation) and at each exacerbation were examined for a panel of 34 respiratory pathogens using commercially available RT-PCR kits and compared to results obtained using culture methods for the detection of bacteria. RESULTS: Participants provided 29 baseline samples and 71 samples at exacerbation. In 17/29 baseline samples, RT-PCR analysis confirmed the organism demonstrated by culture, while 12 samples showed a discrepancy from culture results. Most exacerbations (57.7%) were not associated with acquiring new bacteria or viruses, while 19.8% showed new bacteria, 15.7% new viruses and 7% both new viruses and bacteria. CONCLUSION: Over half of exacerbations were not associated with new organisms in this cohort of participants with chronic bronchitis and colonisation. However, 26.8% demonstrated a new bacterial species in sputum, which is relevant for antibiotic therapy. Baseline RT-PCR and culture results were discordant in one-third of participants.

[Analysis of Antibiotic Resistance of Bioaerosols from Wastewater Treatment Process].

To explore the prevalence and source of antibiotic resistant genes （ARGs） and pathogenic antibiotic resistant bacteria （PARB） associated with bioaerosols in wastewater treatment plants （WWTPs）, metagenomic sequencing and assembly were applied to elucidate the antibiotic resistome of bioaerosols and wastewater in WWTPs. The results showed that more subtypes of ARGs and a higher abundance of PARB were found in bioaerosols from WWTPs and downwind than those from upwind. Multidrug and macB were respectively the most dominant type and subtype of ARGs in bioaerosols from WWTPs. In total, 37 types of PARB carried at least two or more ARG types and were characterized by multiple drug resistance. At the fine grid, aerated tank, and sludge dewatering room, wastewater was the main source of bioaerosol ARGs and PARB. A total of 32 PARB were easily aerosolized in at least one wastewater treatment unit, such as Pseudomonas aeruginosa and Escherichia coli. This study will provide theoretical support for the risk assessment and health protection of antibiotic resistant pollution associated with bioaerosols from WWTPs.

Prevalence and mechanisms of aminoglycoside resistance among drug-resistant Pseudomonas aeruginosa clinical isolates in Iran.

BACKGROUND: Aminoglycosides have been a cornerstone of the treatment of nosocomial infections caused by Pseudomonas aeruginosa for over 80 years. However, escalating emergence of resistance poses a significant challenge. Therefore, this study aimed to investigate the prevailing patterns of aminoglycoside resistance among clinical isolates of P. aeruginosa in Iran; as well as the underlying resistance mechanisms observed in patients referred to Ardabil hospitals. METHODS: A total of 200 isolates from five hospitals were evaluated. The resistance profiles of P. aeruginosa isolates to tobramycin, amikacin, and netilmicin were determined using the disk diffusion method. The capacity of aminoglycoside-resistant isolates to form biofilms was assessed through a phenotypic assay, and the results were confirmed using the gene amplification technique. The presence of genes associated with aminoglycoside resistance was detected using polymerase chain reaction (PCR). Quantitative reverse transcription PCR (qRT-PCR) was performed to measure the expression levels of genes encoding the MexXY-OprM efflux pump and PhoPQ two-component system (TCS). RESULTS: The prevalence of aminoglycoside-resistant P. aeruginosa isolates was 48%, with 94.7% demonstrating multidrug resistance (MDR). All aminoglycoside-resistant P. aeruginosa strains exhibited biofilm-forming capabilities and harbored all the genes associated with biofilm production. Among the nine genes encoding 16S rRNA methylase and aminoglycoside-modifying enzymes, three genes were detected in these isolates: aac(6')-Ib (85.4%), ant(2'')-Ia (18.7%), and aph(3')-VI (3.1%). Additionally, all aminoglycoside-resistant P. aeruginosa isolates carried mexY and phoP genes, although the expression levels of mexY and phoP were 75% and 87.5%, respectively. CONCLUSION: Given the considerably high prevalence of aminoglycoside-resistant P. aeruginosa strains, urgent measures are warranted to transition towards the use of novel aminoglycosides and to uphold vigilant surveillance of resistance patterns.

Bacteriological quality and physicochemical analysis of the Kalte River at Wolaita Sodo Town, southern Ethiopia.

OBJECTIVE: The current research aimed to investigate the physicochemical and bacteriological quality status of the Kalte River in Wolaita Sodo Town, southern Ethiopia. METHODS: A total of 42 water samples were collected using sterile glass bottles from three different river sites: Damota (upstream), Kera (midstream), and Gututo (downstream). All the water samples were examined for the presence of heterotrophic bacteria, total coliform and fecal coliform using direct plate count method and membrane filtration method. Standard methods suggested by American water works association were used to analysis the physicochemical parameters of the water samples. RESULTS: The results revealed that the total heterotrophic bacteria, total coliform, and fecal coliform count ranged from 8.9 to 12.6 × 104 cfu/ml, 7.5-11.3 × 102 cfu/ml and 5.7-9.7 × 104 cfu/ml, respectively. The bacterial count results indicated that the river water crossed the WHO-recommended limit of potable water. Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella, and Shigella species were the common bacterial pathogens isolated from river water samples. The results of the physicochemical analysis revealed that some of the parameters Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and turbidity exceeded the maximum permissible limits of WHO and other parameters were below the WHO permissible limits. CONCLUSION: Therefore, the presence of bacterial pathogens, fecal coliform indicators, and some physicochemical parameters of the Kalte River exceeding the recommended limits may expose users of the river water to the risk of infection.

Prevalence and antimicrobial susceptibility patterns of bacteria colonizing the external ocular surfaces of patients undergoing ocular surgeries at Bugando Medical Center in Mwanza, Tanzania.

OBJECTIVE: Understanding microbiota colonizing ocular surfaces is key to expedite antibiotic prophylactic options for ocular surgeries, and therefore, prevent subsequent surgical site infections (SSIs). To fill this critical gap, we aimed at determining the prevalence and antibiotic susceptibility patterns of bacteria colonizing the external ocular surfaces of 224 patients undergoing ocular surgeries at Bugando Medical Centre (BMC) in Mwanza, Tanzania between May and August 2023. RESULTS: The study participants had a median age of 62.5 (interquartile range: 39.5-75.0) years. A total of 78.1% (175/224) ocular swabs were culture positive yielding 196 bacterial isolates. Staphylococcus epidermidis [43.4% (n = 85)], Staphylococcus aureus [21.9% (n = 43)] and Pseudomonas aeruginosa [14.3% (n = 28)] were the most common bacteria. There were low proportions of resistance among predominant Gram-positive and Gram-negative bacteria to gentamicin (≤ 25.0%), and similarly, low resistance among Gram negative bacteria was observed against 3rd generation cephalosporins (≤ 25.0%) and piperacillin-tazobactam (0.0%). Variable resistance profiles were notable to the most commonly used antibiotics (ciprofloxacin and tetracycline: 0.0-66.7%). Our findings underscore an urgent need to revisit antibiotic prophylactic guidelines for ocular surgeries in this tertiary hospital, and calls for prospective evaluation of incident SSIs post-ocular surgeries to guide specific management.

The bacterial profile and antibiotic susceptibility in skin and soft tissue infections at a tertiary care hospital of Quetta, Pakistan.

Objectives: To determine the bacterial profile and antibiotic susceptibility in skin and soft tissue infections among patients in a tertiary care setting. METHODS: The cross-sectional cohort study was conducted at the Centre for Advanced Studies in Vaccinology and Biotechnology, University of Balochistan, Quetta, Pakistan, from June 2021 to May 2022, and comprised bacteriainfected skin samples that were collected from the Bolan Medical Complex Hospital, Quetta, and the Sandeman Provincial Hospital, Quetta. The swab samples were immediately cultured, and positive samples were evaluated for biochemical tests, antibiotic susceptibility test and polymerase chain reaction. Data was analysed using SPSS 22. RESULTS: Of the 800 samples, 598(74.7%) tested positive for pathogenic bacteria. Staphylococcus aureus accounted for 316(39.5%) infections, followed by clostridium perfringens 18.96(2.37%), escherichia coli 120(15.12%), pseudomonas aeruginosa 98(12.25%) and klebsiella pneumoniae 44(5.5%). Among all the infected samples, 380(47.5%) belonged to males, 218(27.25%) to patients aged 5-20 years, 448(56%) to the uneducated subjects, and 462(57.87%) to patients having lower socioeconomic status. Pseudomonas aeruginosa showed the highest level of resistance against all antibiotics. Conclusion: Regular surveillance and proper use of antibiotics should be encouraged in hospitals to limit the spread of antibiotic resistance against pathogenic bacteria.

[Clinical profiles of community-acquired Pseudomonas aeruginosa infections in children].

Objectives: To investigate clinical characteristics, outcomes and antimicrobial resistance of community-acquired Pseudomonas aeruginosa (CAPA) infections in Chinese pediatric patients. Methods: This retrospective study was conducted at 6 tertiary hospitals in China during January 2016 to December 2018. The clinical and microbiological data of CAPA infected hospitalized children in Hainan and in other regions were collected and compared, and the antimicrobial resistance patterns, clinical characteristics and antibiotic therapy were analyzed. Between different groups were compared using the Chi-square test and Mann-Whitney U test. Results: Among 91 patients, 63 cases were males, 28 cases were females, and 74 cases were from Hainan province, 17 cases were from other regians. The age of consultation was 22.5 (5.4, 44.0) months. Twenty-four cases (26%) had underlying diseases. Fever (79 cases (87%)) and cough (64 cases (70%)) were common initial symptoms. Other concomitant symptoms included wheezing 8 cases (9%), diarrhea 3 cases (3%) and vomiting 4 cases (4%). Twenty-eight cases (31%) had organ infections, including pneumonia 22 cases (24%), skin infection 5 cases (5%), meningitis, intra-abdominal infection and upper urinary tract infection each 1 case (1%). The resistance rate of CAPA isolates to cefepime (4% (4/90)), amikacin (1% (1/90)), ciprofloxacin (2% (2/90)) and levofloxacin (1% (1/89)) was low, and to ceftazidime, piperacillin, piperacillin-azobactam, carbapenem was 12% (11/90), 3/16, 18% (10/56) and 6% (5/90), respectively. Antimicrobial combination therapy accounted for 52% (47/91) of empirical therapy and 59% (52/88) of definite therapy. Two cases (2%) were hopeless discharged, and 3 cases (3%) died during hospitalization. The worse prognosis of CAPA infection is significantly different among children in other regions and in Hainan (4/17 vs. 1% (1/74), χ²=9.74, P<0.05). Conclusions: The invasive CAPA-infection has regional difference in incidence and prognosis in China. Clinical symptoms and signs are non-specific. CAPA strains isolated from pediatric patients display low level of resistance to most of the common antipseudomonal antibiotics. The proportion of poor prognostic outcome is lower in Hainan than in other regions.

Rapid differentiation of cystic fibrosis-related bacteria via reagentless atmospheric pressure photoionisation mass spectrometry.

Breath analysis is an area of significant interest in medical research as it allows for non-invasive sampling with exceptional potential for disease monitoring and diagnosis. Volatile organic compounds (VOCs) found in breath can offer critical insight into a person's lifestyle and/or disease/health state. To this end, the development of a rapid, sensitive, cost-effective and potentially portable method for the detection of key compounds in breath would mark a significant advancement. Herein, we have designed, built and tested a novel reagent-less atmospheric pressure photoionisation (APPI) source, coupled with mass spectrometry (MS), utilising a bespoke bias electrode within a custom 3D printed sampling chamber for direct analysis of VOCs. Optimal APPI-MS conditions were identified, including bias voltage, cone voltage and vaporisation temperature. Calibration curves were produced for ethanol, acetone, 2-butanone, ethyl acetate and eucalyptol, yielding R2 > 0.99 and limits of detection < 10 pg. As a pre-clinical proof of concept, this method was applied to bacterial headspace samples of Escherichia coli (EC), Pseudomonas aeruginosa (PSA) and Staphylococcus aureus (SA) collected in 1 L Tedlar bags. In particular, PSA and SA are commonly associated with lung infection in cystic fibrosis patients. The headspace samples were classified using principal component analysis with 86.9% of the total variance across the first three components and yielding 100% classification in a blind-sample study. All experiments conducted with the novel APPI arrangement were carried out directly in real-time with low-resolution MS, which opens up exciting possibilities in the future for on-site (e.g., in the clinic) analysis with a portable system.

A Label-Free Fluorescent Amplification Strategy for High-Sensitive Detection of Pseudomonas aeruginosa based on Protective-EXPAR (p-EXPAR) and Catalytic Hairpin Assembly.

This study presents a fluorescent mechanism for two-step amplification by combining two widely used techniques, exponential amplification reaction (EXPAR) and catalytic hairpin assembly (CHA). Pseudomonas aeruginosa (P. aeruginosa) engaged in competition with the complementary DNA in order to attach to the aptamer that had been fixed on the magnetic beads. The unbound complementary strand in the liquid above was utilized as a trigger sequence to initiate the protective-EXPAR (p-EXPAR) process, resulting in the generation of a substantial quantity of short single-stranded DNA (ssDNA). The amplified ssDNA can initiate the second CHA amplification process, resulting in the generation of many double-stranded DNA (dsDNA) products. The CHA reaction was initiated by the target/trigger DNA, resulting in the release of G-quadruplex sequences. These sequences have the ability to bond with the fluorescent amyloid dye thioflavin T (ThT), generating fluorescence signals. The method employed in this study demonstrated a detection limit of 16 CFU/ml and exhibited a strong linear correlation within the concentration range of 50 CFU/ml to 105 CFU/ml. This method of signal amplification has been effectively utilized to create a fluorescent sensing platform without the need for labels, enabling the detection of P. aeruginosa with high sensitivity.

Incidence of drug-resistant pathogens in community-acquired pneumonia at a safety net hospital.

The 2019 Infectious Diseases Society of America guideline for the management of community-acquired pneumonia (CAP) emphasizes the need for clinician to understand local epidemiological data to guide selection of appropriate treatment. Currently, the local distribution of causative pathogens and their associated resistance patterns in CAP is unknown. A retrospective observational study was performed of patients admitted to an 870-bed safety net hospital between March 2016 and March 2021 who received a diagnosis of CAP or healthcare-associated pneumonia within the first 48 hours of admission. The primary outcome was the incidence of CAP caused by methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa (PsA) as determined by comparing the number of satisfactory sputum cultures or blood cultures with these drug-resistant organisms to the total number of reviewed patients. Secondary outcomes studied included risk factors associated with CAP caused by drug-resistant organisms, utilization of broad-spectrum antibiotics, appropriate antibiotic de-escalation within 72 hours, and treatment duration. In this 220-patient cohort, MRSA or PsA was isolated from three sputum cultures and no blood cultures. The local incidence of drug-resistant pathogens among the analyzed sample of CAP patients was 1.4% (n = 3/220). The overall incidence of CAP caused by MRSA or PsA among admitted patients is low at our safety-net county hospital. Future research is needed to identify local risk factors associated with the development of CAP caused by drug-resistant pathogens.IMPORTANCEThis study investigates the incidence of drug-resistant pathogens including methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa among community-acquired pneumonia (CAP) patients at a safety net hospital. Understanding local bacteria resistance patterns when treating CAP is essential and supported by evidence-based guidelines. Our findings empower other clinicians to investigate resistance patterns at their own institutions and identify methods to improve antibiotic use. This has the potential to reduce the unnecessary use of broad-spectrum antibiotic agents and combat the development of antibiotic resistance.

Purification of a chemotherapeutic agent, L-Arginase, from Pseudomonas aeruginosa isolated from soil.

INTRODUCTION: L. arginase refers to the enzyme arginase found in the genus Lactobacillus, it plays a crucial role in the urea cycle, and has implications in various biological applications. This study aimed to purify arginase from Pseudomonas aeruginosa, isolated from soil, and apply it as an anticancer. METHODOLOGY: 28 soil samples of P. aeruginosa were collected from different places of Baghdad, and rice lands in Najaf and Diwaniyah governorates. Different standard laboratory and biochemical assays, and Vitik system were used in diagnosis and growth of arginase enzyme under certain pH, temperature, incubation period. RESULTS: The purified enzyme was precipitated by ammonium sulfite (60-80%), dialyses bag 8000-1000KD, ion exchange by DEAE cellulose and sephadex G100 in gel filtration. Cytotoxicity of arginase against breast t cancer AJM-13 and rat embryo fibroblast REF normal cell line was evaluated for (48 and 72 hours). The inhibition rate increased in the low concentration of abnormal cell (AMJ-13) while decreased in the normal cell (REF), this study takes different concentration (0.392-12.5mg/mL), and low concentration (1562-0.048 mg/mL), the result in high concentration was IR 54.7% during 72 hours for AJM-13 and 14.3% for REF in the same time, while the low concentration was IR 91% in the 1562 mg/mL in the AMJ-13, and 51% in ERF, LD50 of arginase enzyme was 0.781 mg/mL that 41% during 72 hours for ERF, its save to normal cells. CONCLUSIONS: Arginase enzyme, at low concentrations, may have an inhibitory effect on cancer cells, and simultaneously, protect normal cell lines.

Point-of-care testing of Pseudomonas aeruginosa using PCN-222(Pt) prepared by nanoconfinement-guided protocol to catalyze gas generation reaction.

BACKGROUND: Pathogenic bacteria are keeping threatening global public health since they can cause many infectious diseases. The traditional microorganism identification and molecular diagnostic techniques are insufficiently sensitive, time-consuming, or expensive. Thus it is of great interest to establish pressure signal-based sensing platforms for point-of-care testing of pathogenic bacteria to achieve timely diagnosis of infectious diseases. Rational design and synthesis of nano-sized probes with high peroxidase-mimicking activity have been a long-term cherished goal for improving the sensitivity of pressure signal-based sensing methods. RESULTS: Guided by nanoconfinement effect, PCN-222(Pt) was prepared by confining Pt clusters within the channels of a zirconium porphyrin MOFs material termed as PCN-222. In comparison to regular platinum nanoparticles, palladium@platinum core-shell nanodendrites, and platinum-coated gold nanoparticles, the prepared PCN-222(Pt) displayed superior peroxidase-mimicking activity with outstanding efficiency for catalyzing the decay of H2O2 to produce O2. Thus it was used as a pressure signal probe to establish a sensitive method on a hydrogel pellets platform for analyzing Pseudomonas aeruginosa (P. aeruginosa), for which polymyxin B and a phage termed as JZ1 were used as recognition agents for the target pathogen. P. aeruginosa was quantified with a handheld pressure meter within a broad range of 2.2 × 102-2.2 × 107 cfu mL-1. This method was used to quantify P. aeruginosa in various biological and food samples with acceptable accuracy and reliability. SIGNIFICANCE: The proposed nanoconfinement-guided protocol provides a novel approach for rational design and preparation of nano-sized probes with high peroxidase-mimicking activity for catalyzing gas-generation reaction. Thus this study opens an avenue for establishment of sensitive pressure signal-based sensing methods for pathogenic bacteria, which shows broad application prospects in medical diagnosis of infectious diseases.

Analysis of mcr family of colistin resistance genes in Gram-negative isolates from a tertiary care hospital in India.

AIM: Colistin serves as the drug of last resort for combating numerous multidrug-resistant (MDR) Gram-negative infections. Its efficacy is hampered by the prevalent issue of colistin resistance, which severely limits treatment options for critically ill patients. Identifying resistance genes is crucial for controlling resistance spread, with horizontal gene transfer being the primary mechanism among bacteria. This study aimed to assess the prevalence of plasmid-mediated mcr genes associated with colistin resistance in Gram-negative bacteria, utilizing both genotypic and phenotypic tests. METHODS AND RESULTS: The clinical isolates (n = 913) were obtained from a tertiary care center in Chennai, India. Colistin resistance was seen among Gram-negative isolates. These strains underwent screening for mcr-1, mcr-3, mcr-4, and mcr-5 genes via conventional PCR. Additionally, mcr-positive isolates were confirmed through Sanger sequencing and phenotypic testing. The bacterial isolates predominantly comprised Klebsiella pneumoniae (62.43%), Escherichia coli (19.71%), Pseudomonas aeruginosa (10.73%), and Acinetobacter baumannii (4.81%), along with other species. All isolates exhibited multidrug resistance to three or more antibiotic classes. Colistin resistance, determined via broth microdilution (BMD) using CLSI guidelines, was observed in 13.08% of the isolates studied. Notably, mcr-5 was detected in K. pneumoniae in PCR, despite its absence in Sanger sequencing and phenotypic tests (including the combined-disk test, colistin MIC in the presence of EDTA, and Zeta potential assays). This finding underscores the importance of employing multiple diagnostic approaches to accurately identify colistin resistance mechanisms.

Anti-inflammatory response to 1,8-Cineol and associated microbial communities in Otitis media patients.

Chronic Otitis Media (COM) is defined as long term inflammation and colonization with pathogenic bacteria due to a defect or retraction of the tympanic membrane. Surgical interventions are often augmented by antibiotic resistance development and therefore, off-label treatment using the natural drug 1,8-Cineol was carried out. All COM patients underwent antibiotic therapy and middle ear surgery and developed antibiotic resistances. Microbiological investigations from the auditory canal and stool samples were performed in correlation with the clinical course. Therapy of COM patients with 1,8-Cineol revealed a clear reduction of inflammatory microbes P. aeruginosa and Proteus mirabilis in ear samples as well as intestinal Prevotella copri, which was associated with an improved clinical outcome in certain individuals. The present off-label study revealed manifold anti-inflammatory effects of the natural monoterpene 1,8-Cineol in Otitis media patients. A better understanding of the underlying mechanisms will improve the current treatment options and possible forms of application of this natural drug.