A random forest model based on core genome allelic profiles of MRSA for penicillin plus potassium clavulanate susceptibility prediction

Treatment failure of methicillin-resistant Staphylococcus aureus (MRSA) infections remains problematic in clinical practice because therapeutic options are limited. Penicillin plus potassium clavulanate combination (PENC) was shown to have potential for treating some MRSA infections. We investigated the susceptibility of MRSA isolates and constructed a drug susceptibility prediction model for the phenotype of the PENC. We determined the minimum inhibitory concentration of PENC for MRSA (n=284) in a teaching hospital (SRRSH-MRSA). PENC susceptibility genotypes were analysed using a published genotyping scheme based on the mecA sequence. mecA expression in MRSA isolates was analysed by qPCR. We established a random forest model for predicting PENC-susceptible phenotypes using core genome allelic profiles from cgMLST analysis. We identified S2-R isolates with susceptible mecA genotypes but PENC-resistant phenotypes; these isolates expressed mecA at higher levels than did S2 MRSA (2.61 vs 0.98, P<0.05), indicating the limitation of using a single factor for predicting drug susceptibility. Using the data of selected UK-sourced MRSA (n=74) and MRSA collected in a previous national survey (NA-MRSA, n=471) as a training set, we built a model with accuracies of 0.94 and 0.93 for SRRSH-MRSA and UK-sourced MRSA (n=287, NAM-MRSA) validation sets. The AUROC of this model for SRRSH-MRSA and NAM-MRSA was 0.96 and 0.97. Although the source of the training set data affects the scope of application of the prediction model, our data demonstrated the power of the machine learning approach in predicting susceptibility from cgMLST results.

In Vitro Development of a New Sponge-Based Delivery System for Intracanal Antimicrobial Administration in Endodontic Treatment

This study aimed to evaluate the in vitro performance of collagen-based sponges as a drug delivery system for intracanal antimicrobial administration. Four groups of loaded collagen-based sponges (A, 0.3% w/v amoxicillin trihydrate: potassium clavulanate (4:1); B, 0.03% w/v chlorhexidine gluconate [CHX]; C, 0.3% w/v amoxicillin trihydrate: potassium clavulanate (4:1) and 0.03% w/v CHX; D, 1% w/v amoxicillin trihydrate: potassium clavulanate (4:1) and 0.03% w/v CHX) were designed. Release kinetics were tested in vitro on cultures in Petri dishes, and the effect on bacterial biofilms was studied ex vivo on 114 extracted human single-rooted teeth. Biofilm formation was tested by scanning electron microscopy (SEM). Collagen sponges containing amoxicillin and chlorhexidine showed a time-sustained antimicrobial effect in vitro and were also able to destroy mature biofilms ex vivo. This datum was validated by means of SEM-based study of E. faecalis and S. aureus biofilms.

Human Saliva-Mediated Hydrolysis of Eugenyl-β-D-Glucoside and Fluorescein-di-β-D-Glucoside in In Vivo and In Vitro Models

Eugenyl-β-D-glucopyranoside, also referred to as Citrusin C, is a natural glucoside found among others in cloves, basil and cinnamon plants. Eugenol in a form of free aglycone is used in perfumeries, flavourings, essential oils and in medicinal products. Synthetic Citrusin C was incubated with human saliva in several in vitro models together with substrate-specific enzyme and antibiotics (clindamycin, ciprofloxacin, amoxicillin trihydrate and potassium clavulanate). Citrusin C was detected using liquid chromatography with tandem mass spectrometry (LC-MS/MS). Citrusin C was completely degraded only when incubated with substrate-specific A. niger glucosidase E.C 3.2.1.21 (control sample) and when incubated with human saliva (tested sample). The addition of antibiotics to the above-described experimental setting, stopped Citrusin C degradation, indicating microbiologic origin of hydrolysis observed. Our results demonstrate that Citrusin C is subjected to complete degradation by salivary/oral cavity microorganisms. Extrapolation of our results allows to state that in the human oral cavity, virtually all β-D-glucosides would follow this type of hydrolysis. Additionally, a new method was developed for an in vivo rapid test of glucosidase activity in the human mouth on the tongue using fluorescein-di-β-D-glucoside as substrate. The results presented in this study serve as a proof of concept for the hypothesis that microbial hydrolysis path of β-D-glucosides begins immediately in the human mouth and releases the aglycone directly into the gastrointestinal tract.

Drug utilization study in medicine intensive care unit in tertiary care hospital

Background: The medical intensive care unit (MICU) is a setting were patients who are critically ill are admitted and thus usually receive a large number of drugs of different pharmacological classes due to life threatening illnesses which may be fatal. The various drugs used in MICU and there clinical outcome was investigated in this study.Methods: Patients admitted between January 2017 to June 2018 in Medicine ICU of GMC Aurangabad were included in this study.Results: Total of 351 prescriptions was analyzed from the medicine intensive care unit. Out of 351 patients 243 (69.23%) were male, while 108 (30.77%) were female. The mean age of the patients admitted in MICU was 42.78±18.14 years. The most common type of patients admitted in MICU have the diagnosis of organophosphorous poisoning (25.36%), followed by cerebrovascular accident (15.95%), pneumonitis (10.26%), snake bite (7.12%), chronic kidney disease (5.98%), diabetic ketoacidosis (5.70%) and seizure disorder (3.42%). The most common drugs used were ranitidine (99.71%) and ondansetron (99.43%). Among antibiotics cephalosporins were most commonly used, ceftriaxone (39.03%), cefotaxim (40.46%), cefoperazone and sulbactum (24.22%). Other antibiotics most commonly used were metronidazole (61.25%), amoxicillin and potassium clavulanate (26.78%), piperacillin and tazobactum (11.68%), meropenem (11.40%).Conclusions: In conclusion, we found that in MICU utilization rate of gastroprotective (ranitidine), antiemetic (ondansetron) and antibiotics (cephalosporins) was high. The present study provides valuable insight about the overall pattern of drugs used in medicine intensive care unit.

Urethral Obstruction in a Female Cat

Background: This work reports a case of urethral obstruction by urolith in a female cat. The patient had a history of hematuria beginning approximately 2 months before visiting the clinic, with anorexia, apathy, emesis, tenesmus and absence of urination. Following physical and ultrasonic examinations, urethral obstruction by urolith was diagnosed. Although feline lower urinary tract disease (FLUTD) is common in both males and females, a urethral obstruction in female cats is extremely rare. This report aims to alert veterinarians to such an occurrence, highlighting the importance of early diagnosis and treatment in view of the severity of the consequences of a urethral obstruction.Case: An undefined, female cat of indefinite age, with a history of hematuria, emaciation, anorexia, apathy, emesis, tenesmus and anuria, presented at our clinic. Physical examination revealed dehydration, discrete rectal prolapse and dysuria. During abdominal palpation, a rigid spherical-shaped structure was observed in the hypogastric region, and complementary examinations were subsequently performed. Hematological examination revealed leukocytosis and increased serum urea and creatinine levels. Abdominal ultrasound examination showed that the urinary vesicle was full, with heterogeneous anechoic content with discrete sedimentation, as well as the presence of a hyperechogenic structure that formed an acoustic shadow at the transition between the bladder trigone and the urethra. In addition, both renal pelves presented dilatation byanechoic content, and measured about 0.5 cm. Treatment with amoxicillin and potassium clavulanate (20 mg/kg administered intravenously) was initiated, and the patient was referred to undergo a surgical procedure to remove the calculus. When exploring the abdominal cavity, the urinary vesicle was identified, which appeared to be rigid. Ventral cystotomywas performed, and calculus was identified in the proximal urethra, which was ‘milked’ into the bladder and removed. The patient showed good surgical recovery, presenting normorexia and normuria after anesthetic recovery. The patient remained hospitalized for 12 h. On the following day, hematological tests showed improvement in leukocytosis and azotemia, and amoxicillin was prescribed with potassium clavulanate (20 mg/kg 12/12 h), tramadol (4 mg/kg 8/8 h) and ketoprofen (1mg/kg SID). The patient was requested to return for a follow-up appointment 5 days later, but the patient did not return.Discussion: Although the low frequency of urethral obstruction in female felines does not reflect the common occurrence of FLUTD, the present report warns of the importance of the final diagnosis in patients with manifestations of urinary tract disorders, especially female animals, in order to exclude the possibility of urolithiasis. This attention will allow the correct treatment of each condition and complete recovery of the patient, avoiding possible obstructions and serious consequences related to the presence of an obstruction for a prolonged period of time. The present work reported a case of feline urethral obstruction, a condition considered rare for females of this species. Urethral obstruction is considered an emergency in the small animal clinic, and the treatment, which consists of clearing and correcting systemic effects, should be rapid as the consequences for the patient can be severe and permanent, and can even lead to death. The possibility of urethral obstruction was not ignored despite the rare occurrence in females, which allowed for rapid surgical intervention to clear and reestablish the urinary flow, which contributed to the successful recovery of the patient.Keywords: urolithiasis, feline lower urinary tract disease, urethral calculus.