Predisposition of Blood group Non-secretors to Urinary tract infection with Escherichia coli Anti-microbial Resistance and Acute Kidney Injury

Urinary tract infection (UTI) causes significant renal damage and disease severity is compounded by antimicrobial resistance (AMR) and other comorbidities in the patient. Blood group antigens secreted in body fluids (secretor status) are known to play a role in bacterial adhesion and we studied its influence on AMR in UTI. A total of 2758 patients with UTI were studied with urine culture, qualitative and semiquantitative urine microscopy, serum creatinine and secretor status in saliva samples by adsorption-inhibition method. Of these, AMR from 300 patients with E. coli infection were assessed as per CLSI 2019 guidelines and extended-spectrum beta-lactamase (ESBL) genes (bla TEM, bla CTX-M, bla SHV) and NDM1 genes were studied using TaqMan probes in Real-time polymerase chain reaction. Patients with UTI were followed up for two weeks. Female patients had higher predilection (57%) for E. coli infection while patients with diabetes or non-secretors had none. In our study, ESBL producers were seen in 62% of the E. coli isolates and fosfomycin had 100% susceptibility. Non-secretors were significantly associated with acute kidney injury (AKI), AMR and ESBL genes. Multidrug-resistant (MDR) was noted in 127/160 (79.4%) ESBL and 17/18 (94%) NDM1 gene encoding strains. Quantitative urine microscopy scoring predicted AKI both at presentation and at end of follow up. ESBL producers were common in our study population and non-secretors had a significant association with AMR genes. Urine microscopy scoring system may be a useful tool to predict AKI in patients with UTI.

A comparative study of various screening tests of Asymptomatic Bacteriuria in pregnant women attending Antenatal Outpatient Department’

Introduction: Urinary tract infections are the most common bacterial infections in pregnancy.Asymptomatic bacteriuria (ASB) refers to the presence of bacteria in the urine of an individualwithout symptoms of urinary tract infection. ASB which occurs in 2-11% of pregnancies is a majorpredisposition to the development of pyelonephritis. Aims and objectives: The aims and objectivesof the study were to: Study the effectiveness of various screening tests: urine microscopy, gramstain, catalase test, leukocyte esterase test and nitrite test and to compare their sensitivity,specificity, positive predictive value and negative predictive value. Materials and Methods: Thestudy included 500 pregnant women attending the outpatient department over 18 months. The urinesamples collected in sterile containers were screened for urine microscopy, gram stain, catalase test,leukocyte esterase test and nitrite test. The samples were processed on CLED (Cysteine lactoseelectrolyte deficient) agar as the standard against which other screening tests are identified.Results: Gram’s stain (89.34%) was the most sensitive of all and the least reliable test was thecatalase test among the methods of screening tests. Conclusion: Urine culture is considered to bethe gold standard in detecting ASB in pregnant women. Gram’s stain of urine is a good screeningtest when compared to other screening methods. Screening for bacteria in all trimesters isnecessary to prevent the dangerous complications associated with ASB.

MO319BEDSIDE URINE SEDIMENT EXAMINATION IN IMMUNOGLOBULIN A NEPHROPATHY PATIENTS PERFORMED BY NEPHROLOGISTS

Background and Aims Urine sediment microscopy is mostly abandoned by nephrologists nowadays, however it is an important diagnostic tool in kidney and urinary tract diseases. The aim of this study is to emphasize the benefits of urine microscopy performed by a nephrologist. Method A prospective cohort study at Pauls Stradins Clinical University Hospital Nephrology center included patients with histologically confirmed diagnosis of IgA nephropathy from 1st January 2020 till December 2020. Appropriately collected urine samples were examined using manual microscopy within an hour after sample collection and by automated urinalysis. Samples were centrifuged at 4000 rpm for 4 minutes, the supernatant urine was carefully decanted, 1 - 1,5 ml of the left urine was mixed by gentle agitation and placed on a standard glass slide with a cover slip. Sample examination was performed using low (magnification x10) and high power (magnification x40) using brightfield microscopy with a minimum of 10 fields. Results A total of 37 patients (24 men, mean age 42.7 ± 10.9 years) were included in the study. 59.5 % of patients (n = 22) had hematuria based on automated urine sediment analysis and 62.2 % (n = 23) of patients had hematuria based on manual urine microscopy. 45.9 % of patients (n=17) had dysmorphic erythrocytes, 13.5 % of patients (n = 5) had isomorphic red blood cells (RBC) and 40.5 % of patients (n = 15) did not have RBC in urine samples by manual urine microscopy. 54.2 % (13/24) of men and 30.8 % (4/13) of women had dysmorphic RBC in urine. Conclusion Manual urine sediment examination was more sensitive than automated analysis. Majority of IgA nephropathy patients have active urine sediment with hematuria and dysmorphic RBC. Manual microscopy remains an effective and reliable method that can be easily and quickly performed by nephrologists.

Reevaluating the true diagnostic accuracy of dipstick tests to diagnose urinary tract infection using Bayesian latent class analysis

Objective Previous studies on diagnostic accuracy of dipstick testing for leukocyte esterase (LE) and nitrite to diagnose urinary tract infection (UTI) had used urine culture, which is an imperfect gold standard. Estimates of diagnostic accuracy obtained using the classical gold standard framework might not reflect the true diagnostic accuracy of dipstick tests. Methods We used the dataset from a prospective, observational study conducted in the emergency department of a teaching hospital in southern India. Patients with a clinical suspicion of UTI underwent dipstick testing for LE and nitrite, urine microscopy, and urine culture. Based on the results of urine microscopy and culture, UTI was classified into definite, probable, and possible. Patients with microscopic pyuria and a positive urine culture were adjudicated as definite UTI. Unequivocal imaging evidence of emphysematous pyelonephritis or perinephric collections was also considered definite UTI. We estimated the diagnostic accuracy of LE and nitrite tests using the classical analysis (assuming definite UTI as gold standard) and two different Bayesian latent class models (LCMs; 3-tests in 1-population and 2-tests in 2-populations models). Results We studied 149 patients. Overall, 64 (43%) patients had definite, 76 (51%) had probable, and 2 (1.3%) had possible UTI; 7 (4.6%) had alternate diagnoses. In classical analysis, LE was more sensitive than nitrite (87.5% versus 70.5%), while nitrite was more specific (24% versus 58%). The 3-tests in 1-population Bayesian LCM indicated a substantially better sensitivity and specificity for LE (98.1% and 47.6%) and nitrite (88.2% and 97.7%). True sensitivity and specificity of urine culture as estimated by the model was 48.7% and 73.0%. Estimates of the 2-tests in 2-populations model were in agreement with the 3-tests in 1-population model. Conclusions Bayesian LCMs indicate a clinically important improvement in the true diagnostic accuracy of urine dipstick testing for LE and nitrite. Given this, a negative dipstick LE would rule-out UTI, while a positive dipstick nitrite would rule-in UTI in our study setting. True diagnostic accuracy of urine dipstick testing for UTI in various practice settings needs reevaluation using Bayesian LCMs.

Urine Tests for Diagnosis of Infectious Diseases and Antibiotic-Resistant Pathogens

The relation between disease and urine was recognized by physicians since the earliest civilization BC. Urine is considered an ideal diagnostic specimen for its noninvasive and easy method of collection. Urinalysis encompasses a wide range of tests, which includes a variety of chemical tests, urine microscopy, bacterial cultures, and molecular tests. Importantly, urine tests can diagnose patients with antibiotic-resistant urinary tract infections (UTI), directly from urine and/or bacterial culture. This chapter summarizes the most common urine tests in the infectious disease field, with a special focus on diagnosing UTI and characterizing their antibiotic resistant. In addition to describing the advantages and limitation of these tests, the chapter explores the promising emerging technologies and methods in this field. This chapter is beneficial for scientists and healthcare workers in the field.

Urine Microscopy for Internal Medicine Residents: A Needs Assessment & Implementation of Virtual Teaching Sessions

Background: Though urine microscopy is an important step in the initial evaluation of a patient with kidney disease, internal medicine residents have minimal exposure to this technique during their training. The goal of this study was to understand knowledge of and attitudes towards urine microscopy among internal medicine residents, and to implement virtual urine microscopy teaching sessions. Methods: A voluntary, anonymous, online survey was sent to all the categorical internal medicine residents training (n = 131) at the Icahn School of Medicine at Mount Sinai (ISMMS). The survey included thirteen questions to assess attitudes towards, experience with, and clinical interpretation of urine microscopy specimens. In response to the survey results, we implemented virtual urine microscopy teaching sessions using video conferencing software which incorporated real-time urine sediment analysis with nephrology fellows and attending nephrologists. Results: The survey response rate was 45% (59/131). Forty-seven percent (28/59) of respondents reported performing urine microscopy at least once during their training and 75% (44/59) of respondents did not feel comfortable performing urine microscopy. The majority of residents (92%, 54/59) reported they felt urine microscopy was very helpful or somewhat helpful in the evaluation of patients with AKI. Overall, 41% percent of responses to clinical interpretation questions were considered correct. Following survey completion, virtual urine microscopy sessions were held monthly and well received by the participants. Conclusions: Our study found that internal medicine residents perceive urine microscopy as a helpful diagnostic tool, though lack the skills to perform and interpret urine microscopy sediments. Virtual educational sessions using video conferencing software are a technically feasible approach to teaching urine microscopy to internal medicine residents. Future studies include a study of the impact of these sessions on learning of urine microscopy.

Pyrexia of unknown origin associated with a non-infected vaginal shelf pessary

An 82-year-old female was admitted with pyrexia and rigors. Bloods showed a raised C-reactive protein and she was commenced on empirical intravenous antibiotics. Chest X-ray, urine microscopy and computed tomography scan of the patient’s abdomen and pelvis did not demonstrate a source of infection, and blood cultures did not grow a microorganism. A collateral history was taken from the patient’s husband who raised concerns regarding her vaginal shelf pessary and it was therefore removed. Subsequently the patient’s fever subsided, her inflammatory markers improved and she was discharged 2 days later. We believe this is the first reported case of pyrexia secondary to a non-infected vaginal pessary, and may provide clinicians with an additional line of enquiry when presented with patients with pyrexia of unknown origin.