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Results for “antibiotics responsiveness”

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At least 19 recordsLinked to original sources
PubMed2024

Analysis of Antibiotic Response in Clinical Wound Pseudomonas aeruginosa Isolates: Unveiling Proteome Dynamics of Tobramycin-Tolerant Phenotype.

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic human pathogen, causing serious chronic infections. P. aeruginosa can adapt efficiently to antibiotic stressors via different genotypic or phenotypic strategies such as resistance and tolerance. The adaptation regulatory system is not always very well understood. In this study, we use shotgun proteomics to investigate the system-level response to tobramycin in two clinical wound P. aeruginosa isolates and PAO1. We profiled each strain for its antibiotic drug-tolerant phenotype using supra-minimum inhibitory concentrations (supra-MICs) of tobramycin and applied proteomics to investigate the protein expression profiles. The MIC revealed that all isolates were susceptible to tobramycin but at supra-MICs at stationary growth, a degree of tolerance was observed for the isolates. We identified around 40% of the total proteins encoded by the P. aeruginosa genome and highlighted shared and unique protein signatures for all isolates. Comparative proteome profiling in the absence of antibiotic treatment showed divergent fingerprints, despite similarities in the growth behavior of the isolates. In the presence of tobramycin, the isolates shared a common response in the downregulation of proteins involved in the two-component system, whereas stress response proteins were present at higher levels. Our findings provide insight into the use of proteomic tools to dissect the system-level response in clinical isolates in the absence and presence of antibiotic stress.

Pseudomonas aeruginosa↗
PubMed2024

Measuring single-cell susceptibility to antibiotics within monoclonal bacterial populations.

The emergence of new resistant bacterial strains is a worldwide challenge. A resistant bacterial population can emerge from a single cell that acquires resistance or persistence. Hence, new ways of tackling the mechanism of antibiotic response, such as single cell studies are required. It is necessary to see what happens at the single cell level, in order to understand what happens at the population level. To date, linking the heterogeneity of single-cell susceptibility to the population-scale response to antibiotics remains challenging due to the trade-offs between the resolution and the field of view. Here we present a platform that measures the ability of individual E. coli cells to form small colonies at different ciprofloxacin concentrations, by using anchored microfluidic drops and an image and data analysis pipelines. The microfluidic results are benchmarked against classical microbiology measurements of antibiotic susceptibility, showing an agreement between the pooled microfluidic chip and replated bulk measurements. Further, the experimental likelihood of a single cell to form a colony is used to provide a probabilistic antibiotic susceptibility curve. In addition to the probabilistic viewpoint, the microfluidic format enables the characterization of morphological features over time for a large number of individual cells. This pipeline can be used to compare the response of different bacterial strains to antibiotics with different action mechanisms.

Anti-Bacterial Agents↗
PubMed2026

Cranberry juice potentiates sensitivity of uropathogenic Escherichia coli (UPEC) strains to fosfomycin and decreases occurrence of spontaneous resistance.

Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs). The growing prevalence of antimicrobial resistance underscores the need for alternative or complementary strategies to enhance antibiotic activity. Fosfomycin (FOS) remains a recommended first-line treatment for uncomplicated UTIs due to its broad activity and low resistance rates; however, spontaneous resistance frequently arises through mutations in bacterial transport systems. Cranberry juice is known for its anti-adhesive and anti-infective properties; however, its potential to modulate antibiotic activity remains poorly understood. Here, we show that cranberry juice markedly potentiates the antibacterial activity of FOS and limits the emergence of resistance in UPEC clinical isolates. In 72% of the 32 tested isolates, cranberry juice significantly increased FOS inhibition activities and reduced spontaneous FOS-resistant mutant frequencies by up to five orders of magnitude. Whole-genome sequencing revealed distinct mutational patterns: FOS-resistant mutants selected without cranberry juice primarily carried glpT mutations, whereas those obtained with juice harbored mutations in uhpT or associated regulatory genes. Reporter assays indicated that cranberry juice represses glpT expression while maintaining UhpT-mediated FOS uptake, thereby sustaining antibiotic entry and activity. These results demonstrate that cranberry juice alters bacterial carbohydrate transport regulation to potentiate FOS activity and suppress resistance emergence. This study provides novel evidence that a natural product can enhance FOS activity, highlighting its potential as an antibiotic adjuvant for UTI management.IMPORTANCEAntimicrobial resistance is a growing threat to public health, and new strategies are needed to preserve the activity of existing antibiotics. This study reveals that cranberry juice, a widely consumed natural product, enhances the antibacterial activity of fosfomycin against uropathogenic Escherichia coli by modulating bacterial sugar transport systems. By shifting fosfomycin uptake from GlpT- to UhpT-mediated pathways, cranberry juice both potentiates antibiotic activity and suppresses the emergence of resistant mutants. These findings provide new insight into how dietary components can influence antibiotic response, offering a promising basis for developing natural adjuvants that extend the lifespan of current antimicrobial agents.

Fosfomycin↗
PubMed2025

Rapid and accurate sepsis diagnostics via a novel probe-based multiplex real-time PCR system.

Sepsis is a critical clinical emergency that requires prompt diagnosis and intervention. Its prevalence has increased due to the aging population and increased antibiotic resistance. Early identification and the use of innovative technologies are crucial for improving patient outcomes. Modern methodologies are needed to minimize the turnaround time for diagnosis and improve outcomes. Rapid diagnostic tests and multiplex PCR are effective but have limitations in identifying a range of pathogens and target genes. Our study evaluated two novel probe-based multiplex real-time PCR systems: the SEPSI ID and SEPSI DR panels. These systems can quickly identify bacterial and fungal pathogens, alongside antibiotic resistance genes. The assays cover 29 microorganisms (gram-negative bacteria, gram-positive bacteria, yeast, and mold species), alongside 23 resistance genes and four virulence factors. A streamlined workflow uses 2 µL of broth from positive blood cultures (BCs) without nucleic acid extraction and provides results in approximately 1 h. We present the results from an evaluation of 228 BCs and 22 isolates previously characterized by whole-genome sequencing. In comparison to the reference methods, the SEPSI ID panel demonstrated a sensitivity of 96.88%, a specificity of 100%, and a PPV of 100%, whereas the SEPSI DR panel showed a sensitivity of 97.8%, a PPV of 89.7%, and a specificity of 96.7%. Both panels also identified additional pathogens and resistance-related targets not detected by conventional methods. This assay shows promise for rapidly and accurately diagnosing sepsis. Future studies should validate its performance in various clinical settings to enhance sepsis management and improve patient outcomes.IMPORTANCEWe present a new diagnostic method that enables the quick and precise identification of pathogens and resistance genes from positive blood cultures, eliminating the need for nucleic acid extraction. This technique can also be used on fresh pathogen cultures. It has the potential to greatly improve treatment protocols, leading to better patient outcomes, more responsible antibiotic use, and more efficient management of healthcare resources.

Humans↗
PubMed1976

Primary upper small-intestinal lymphomal A report of 40 cases fron Iran.

Primary upper small-intestinal lymphoma (PUSIL) has now been recognized as a distinct clinical entity with a distinct geographic distribution. Herewith are presented 40 cases of PUSIL seen at Pahlavi University Hospitals in Southern Iran. The investigation reveals the lymphoma to be predominantly a disease of those under 30 and males; the major complaints and physical findings point to an intraabdominal disease. An exception has been clubbing and osteoarthropathy. Special features of PUSIL include: (1) protein loss into the gastrointestinal tract leading to hypoalbuminemia and edema; (2) an antibiotic-responsive diarrhea and steatorrhea; and (3) an associated abnormal heavy-chain protein. The study further stresses the importance of peroral small-intestinal biopsy and the pathologic features of this condition.

Adolescent↗
PubMed1978

The temperature sensitive mutant 72c. I. Pleiotropic growth behaviour and changed response to some antibiotics and mutations in the transcription or translation apparatus.

The spontaneous temperature sensitive mutant 72c is shown to be more tolerant to fusidic acid, but less tolerant to trimethoprim on plates at permissive temperature, than is the parental strain. The poor growth of the mutant on amino acids supplemented plates, as well as its inability to grow on broth plates at 40 degrees, can be compensates by sublethal amounts of chloroamphenicol. Also some mutations to Rif-R or Str-R improve growth of the mutant under certain conditions. Reversion and other genetic analysis strongly suggest, that the pleiotropic behaviour of the mutant is due to a single mutation in a gene, which is designated fusB and is closely cotransducible with lip at min 14 of the E. coli chromosome. The gene order is lip-fusB-supE.

Chloramphenicol↗
PubMed1978

Incidence of antibodies to antibiotics in subjects with chronic staphylococcal diseases.

Antibody response to antibiotics in patients with chronic staphylococcal diseases was studied and the results were compared with the production of specific antibodies. Increased titres of antibodies to antibiotics were found in cases with inadequate antibody response. The possibility of an immunosuppressive effect of antibiotics on the formation of specific antistaphylococcal antibodies is discussed.

Anti-Bacterial Agents↗
PubMed1976

Factors influencing the response of Escherichia coli to antibiotics in conditions prevailing in the infected urinary bladder.

The response of a sensitive strain of Escherichia coli to a variety of antibiotics was examined in an in vitro model which simulates the hydrokinetic features of the urinary bladder. Recovery of bacterial cultures from antibiotic effects was observed following exposure to bactericidal and bacteristatic antibiotics and no substantial difference was noted between the effectiveness of bacteristatic and bactericidal agents except that bacteristatic antibiotics were more influenced by alteration of the conditions of "diuresis" and "frequency of micturition". The response of dense bacterial populations to high concentrations of 3 beta-lactam antibiotics varied markedly under the different hydrokinetic conditions. Possible reasons for these variations are discussed.

Ampicillin↗
PubMed1976

Erythema chronicum migrans.

Erythema chronicum migrans is characterized by an expanding erythematous band about an arthropod bite. While rare, it is an important disease to recognize because of its rapid response to even modest doses of antibiotics. This response and the association with arthropod bites suggest a microbial vector. Richettsial titers have been demonstrated in several cases but we were unable to show them in our patient, who we believe is the second reported case of erythema chronicum migrans incurred by an American without traveling abroad.

Adult↗
PubMed1976

Topically applied antibiotics in acne vulgaris: clinical response and suppression of Corynebacterium acnes in open comedones.

Topical antibiotics were used on patients with acne vulgaris. Corynebacterium acnes organisms from open comedones were quantitated during treatment, and the progress of the disease was evaluated. Clindamycin lotion completely suppressed the growth of C acnes organisms, whereas erythromycin and tetracycline did not depress the C acnes counts. Taken as a group, these antibiotics gave a substantial improvement of the disease on the treated side as compared with paired untreated sides of the face and back.

Acne Vulgaris↗
PubMed1977

Antibiotic concentrations in ascitic fluid of patients with ascites and bacterial peritonitis.

Thirty-six paired specimens of serum and ascitic fluid from 21 patients with peritonitis and ascites, most with sponetaneous bacterial peritonitis and alcoholic cirrhosis, were assayed for antibiotic content. Antibiotics assayed and number of determinations were gentamicin, 14; tobramycin, 7; ampicillin, 5; clindamycin, 3; penicillin G, 2; cephalothin, 2; chloramphenico, 2; and cefazolin, 1. In 31 pared specimens the ascitic fluid antibiotic concentration was about one half or more of the simultaneous serum level and in 17 assays exceeded 90% of the serum level. All antibiotics studied penetrated ascitic fluid equally well. Clinical response to antibiotic therapy was good in 12 of 16 patients with culture-proven bacterial peritonitis. Antibiotic levels in ascitic fluid exceeded the minimal inhibitory concentration of the infecting organisms in all but one patient who responded. Direct intraperitoneal instillation of antibiotics does not appear to be necessary routinely; however, there may be an initial lag of several hours before antibiotic concentrations is ascites achieve therapeutic levels.

Adult↗
PubMed1977

The management of febrile episodes in-neutropenic cancer.

The management of 33 febrile episodes in neutropenic patients suffering from acute leukaemia and other cancers is described. In 32 out of 33 episodes, the fever subsided. One patient died of cerebral haemorrhage while infected. The most common clinical sites of infection were, in order of frequency, the chest, the throat and the skin. Positive cultures were obtained in about half the episodes, the most common site being the throat followed by blood and sputum. The most common organisms isolated were Gram negative. Eighty-four per cent of febrile episodes occurred with neutrophil counts of less than 500/mm3, and in the majority of these, less than 100 neutrophils per cubic millmetre. All patients were reverse barrier nursed and on becoming febrile were given 48 hours of parenteral antibiotic therapy. The most common antibiotic combination used was gentamicin and cephalothin. At 48 hours, granulocyte transfusion and a third antibiotic were added to the regimen of patients not responding. The percentage response to antibiotics alone, in this series, at 58% was similar to that of other series, but the mortality experienced was lower.

Agranulocytosis↗
PubMed1979

Antibiotic associated pseudomembranous colitis with negative proctosigmoidoscopy examination.

Most investigators have stressed that the diagnosis of antibiotic associated pseudomembranous colitis is made by proctosigmoidoscopic examination. In our investigation, 6 patients with tissue culture evidence of a clostridial toxin in stools and either normal or only edematous rectal mucosa were studied with total colonoscopy. Five of six patients demonstrated pseudomembranes located in various areas of the colon at a time when the rectosigmoid area was uninvolved. This demonstrates the occurrence of antibiotic associated pseudomembranous colitis which can be missed by routine proctosigmoidoscopy. The incidence of rectal sparing in this disease remains undetermined. Further investigation to determine the occurrence of antibiotic colitis, response to different treatments, or sensitivity of tissue culture assays as a diagnostic aid in antibiotic associated pseudomembranous colitis must take this subgroup into account.

Ampicillin↗
PubMed1977

Inhibition of the immune response by rapamycin, a new antifungal antibiotic.

Rapamycin, a new antifungal antibiotic, was found to inhibit the immune response in rats. It totally prevented the development of two experimental immunopathies (experimental allergic encephalomyelitis (EAE) and adjuvant arthritis (AA)) and the formation of humoral (IgE-like) antibody. It was about half as potent as cyclophosphamide in inhibiting EAE. In AA and on antibody formation, rapamycin and cyclophosphamide were about equipotent, whereas methotrexate was more potent. The immunosuppressant activity of rapamycin appears to be related to inhibition of the lymphatic system.

Animals↗
PubMed1979

[Mechanisms of R-factor coded resistance (author's transl)].

The prevalence of resistance factors (R-factors) has become a serious threat to the chemotherapeutic armament of modern medicine. These extrachromosomal elements exert their effects by supplying the harbouring bacterial cell with the genetic information for detoxifying enzymes, for the expression of biochemical mechanisms which effectively prevent antibiotic molecules from reaching their target or for the synthesis of resistant target molecules. The genes which are responsible for these effects were recently shown to reside on "transposons", genetic entities which can recombine with various DNA moieties, like plasmids, bacterial chromosomes, or the genome of bacteriophages. The transposon nature of most resistance determinants provide the bacterial world with an enormous flexibility in the response to antibiotic selection pressure. It is an absolute requirement for the future to stop further spread of R-factors by reducing the selection pressure. Doctors will have to apply antibiotics more selectively, and in animal breeding and growth promotion only those drugs should be used which are never prescribed for humans. Moreover, pharmaceutical research should be directed towards the development of compounds acting on R-factors or on their enzyme systems.

Anti-Bacterial Agents↗