ABSTRACT
OBJECTIVE: Urine culture as a gold standard for the diagnosis of urinary tract infection (UTI) involves a considerable workload in Clinical Microbiology Departments, due to the high number of samples received that will ultimately be negative. Therefore, it is necessary to use screening systems that also reduce the turnaround time for UTI diagnosis. The new flow cytometer UF-5000 (Sysmex Corporation) is able to differentiate between Gram-negative and Gram-positive bacteria using the BACT-info parameter according to manufacturer. The aim of our study was to evaluate the gram discrimination ability of the UF-5000 cytometer. METHODS: A prospective study with 449 urine samples collected consecutively was conducted, in the period 7/3/2022-27/5/2022, in which the BACT-info flag was compared with urine culture as the reference method. RESULTS: The sensitivity obtained for both Gram-negative and Gram-positive bacteria was above 95%. However, for Gram-positive bacteria, the moderate Kappa index (0.49) and the low positive predictive value (37.1%) indicated that the correlation between BACT-info flag and urine culture was not acceptable and should not be reported to the requesting clinician. CONCLUSIONS: Implementation of the third generation UF-5000 cytometer represents a significant advance in the aetiological orientation of UTIs caused by Gram-negative bacteria. Reporting the Gram morphology in the urine samples reduces the response time in the microbiological diagnosis of UTI, which would have an impact on the reduction and optimisation of empirical treatment, and thus on the generation of antimicrobial resistance.
Subject(s)
Urinary Tract Infections , Humans , Prospective Studies , Urinary Tract Infections/microbiology , Urinalysis/methods , Gram-Positive Bacteria , Gram-Negative Bacteria , Sensitivity and Specificity , Urine/microbiologySubject(s)
Bacteremia , Lactobacillus delbrueckii , Urinary Tract , Bacteremia/drug therapy , HumansABSTRACT
OBJECTIVE: Nowadays, the use of flow-cytometry for the screening of urine samples is extended, but appropriate cut-off points for each population group are yet to be established. The objective of this study was to evaluate the Sysmex UF-1000i® cytometer as a screening method for detection of asymptomatic bacteriuria (AB) and Group B Streptococcus (GBS) in pregnant women. METHODS: Urine samples obtained during pregnancy between January-July 2019 were both processed with the Sysmex UF-1000i® and also cultured. Demographic data, flow-cytometry parameters and the result of the urine culture were collected. To assess the performance of the flow-cytometer for detection of AB and GBS, receiver operating characteristic (ROC) curves for the BACT/µL variable were applied. RESULTS: A total of 33,687 urine samples were received, among which 1,443 (4.3%) belonged to pregnant women. Urine culture was positive in 82 (5.7%) samples, 1,295 (89.7%) were negative and 66 (4.6%) were considered contaminated. GBS was isolated in 69 (4.8%) patients and 46 (66.7%) with a microbial count below 10E4 CFU/mL. For AB detection, the cut-off point of 550 BACT/µL yielded a sensitivity of 91.5%, a negative predictive value of 99.3% and could avoid culturing 74.1% of the samples. No cut-off value could be established for GBS detection. CONCLUSIONS: Although the Sysmex UF-1000i® system is a valid screening method for the AB detection in pregnant population, it is not useful for the identification of GBS bacteriuria in our area. Therefore, the conventional urine culture is still required during pregnancy.
Subject(s)
Bacteriuria/diagnosis , Bacteriuria/microbiology , Flow Cytometry/instrumentation , Flow Cytometry/methods , Mass Screening/methods , Pregnancy Complications, Infectious/diagnosis , Pregnancy Complications, Infectious/microbiology , Streptococcal Infections/diagnosis , Streptococcal Infections/microbiology , Streptococcus agalactiae , Adult , Female , Humans , Predictive Value of Tests , Pregnancy , ROC Curve , Sensitivity and Specificity , Urinary Tract Infections/diagnosisABSTRACT
OBJECTIVE: Spontaneous bacterial peritonitis (SBP) is a frequent and severe entity in patients with cirrhosis or ascites due to other causes. However, Listeria monocytogenes is a microorganism that has been scarcely identified as a causative agent of SBP. METHODS: In this study, a descriptive analysis of cases of L. monocytogenes SBP was carried out in our center for 26 years (1992-2017). RESULTS: A total of eight patients were diagnosed, with an average age of 58 years, with no differences in sex distribution and all of them were community acquired cases. Half of the patients had underlying liver disease, two of them active malignancies; one was undergoing continuous ambulatory peritoneal dialysis and the last one with hypertensive heart disease. Six (75%) of the patients received a third-generation cephalosporin as empirical treatment. The clinical course was favorable after receiving directed antibiotic treatment in five (62.5%) of the patients. However, three of them, under the age of 59, died. Serotyping of L. monocytogenes isolates revealed that half of them were serovar 4, two 1 / 2a and the remaining one 1 / 2c. All strains were susceptible to ampicillin, meropenem, erythromycin and cotrimoxazole. CONCLUSIONS: We conclude by emphasizing the importance of taking this etiology into account in patients with underlying liver disease and with clinical or laboratory data suggesting SBP, mainly due to the need for specific antibiotic treatment different from conventionally empirically used.
