Monitoring fluoroquinolone resistance among ESBL-positive and ESBL-negative Escherichia coli strains isolated from urinary tract infections: An alert for empirical treatment

ABSTRACT Background: Bacterial resistance to extended-spectrum beta-lactamases (ESBL) is present worldwide. Empirical antibiotic therapy is often needed, and the use of fluoroquinolones, such as ciprofloxacin and norfloxacin, is common. This study aimed to analyze the urine cultures from 2,680 outpatients in January 2019, 2020, 2021, and 2022, with bacterial counts above 100,000 CFU/mL in which Escherichia coli was the etiological agent. Methods: We monitored the resistance of ESBL-positive and ESBL-negative strains to ciprofloxacin and norfloxacin and evaluated resistance rates. Results: Significantly higher fluoroquinolone resistance rates were observed among ESBL-positive strains in all years studied. Furthermore, a significant increase in the rate of fluoroquinolone resistance was observed between 2021 and 2022 in ESBL-positive and -negative strains, as well as from 2020 to 2021 among the ESBL-positive strains. Conclusions: The data obtained in the present study showed a tendency towards an increase in fluoroquinolone resistance among ESBL-positive and -negative E. coli strains isolated from urine cultures in Brazil. Since empirical antibiotic therapy with fluoroquinolones is commonly used to treat diverse types of infections, such as community-acquired urinary tract infections, this work highlights the need for continuous monitoring of fluoroquinolone resistance among E. coli strains circulating in the community, which can mitigate the frequency of therapeutic failures and development of widespread multidrug-resistant strains.

MALDI-TOF mass spectrometry identification of yeast-form fungi: a comparison between methods

Introduction: Identification of yeast species has clinical and epidemiological value. Different methods can be used, such as chromogenic media, microculture on corn meal agar with Tween 80, as well as conventional biochemical and automated methods. Recently, proteomic studies employing matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry have been a major advance in diagnosis due to speed of execution and accuracy of results. Methods: For this study, 79 yeast samples were submitted to identification using chromogenic medium, microculture on corn meal-Tween 80 agar, VITEK 2 Compact identification, and MALDI-TOF mass spectrometry. Results: Most of the 79 samples were identified, with differences in the performance of the methods used. Colonial morphology and microscopy were compatible with the genus Candida. MALDI-TOF mass spectrometry had the best performance, with 78 strains identified (98.7%), compared to VITEK 2 Compact (92.4%) and microculture on corn meal agar (70.9%). Conclusions: MALDI-TOF mass spectrometry using the VITEK MS instrument performed best and has proven to be a revolutionary method in clinical microbiology laboratories. Regarding the identification of C. albicans and C. tropicalis, the chromogenic medium had excellent performance, thus being a good option to optimize the process. (AU)

Use of MALDI-TOF MS in diagnostic microbiology for identification of species that conventional methods usually fail to identify

(MALDI-TOF MS) has been used in clinical diagnostic laboratories for the identification of microorganisms. It has a relevant advantage compared to other methods in terms of speed to provide results, being an alternative for addressing restrictions in clinical diagnosis as it may replace or complement existing identification techniques. This is especially important because some rare microorganisms would be identified only by higher cost techniques which are not widely available, such as genetic sequencing. Thus, the present paper reports two cases in which uncommon microorganisms were identified effectively and quickly. (AU)

Susceptibility of Streptococcus agalactiae to erythromycin and clindamycin in pregnant women in the prenatal screening

Introduction: Group B streptococcus (GBS), or Streptococcus agalactiae, is a bacterium found in normal human microbiota. However, it may cause neonatal pneumonia, sepsis, and meningitis. Genital colonization in pregnant women is associated with a higher risk of preterm birth. The treatment of choice is antibiotic therapy with beta-lactams, but in the case of multidrug-resistance, erythromycin and clindamycin can be used. Methods: This study evaluated bacterial cultures in the period from 2014 to 2015 from a group of 29,875 pregnant women. GBS colonization and resistance to erythromycin and clindamycin were investigated. Results: Positive cultures were found in 26.8% and 26.1% of the samples in 2014 and 2015, respectively. Levels of resistance to erythromycin and clindamycin were, respectively, 2.4% and 5.5% in 2014 and 3.2% and 6.5% in 2015. Conclusion: The investigation of GBS colonization and the evaluation of GBS resistance to erythromycin and clindamycin are of extreme relevance, given the increasing incidence of bacterial resistance, risks of preterm birth. (AU)

Identification of Cryptococcus neoformans by MALDI-TOF mass spectrometry in blood culture

This is a report of isolation of Cryptococcus neoformans from blood culture. Identification was conducted by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. The relevance of this report is related to the site affected, the severity of the infection, and the importance of correct and rapid identification of the causative pathogen for a successful treatment and for reducing the risk of morbidity and mortality. (AU)

Identification of Chromobacterium violaceum by MALDI-TOF mass spectrometry in blood culture

Report of Chromobacterium violaceum isolation from blood culture. Identification by MALDI-TOF mass spectrometry. Relevant report due to the site affected, infection severity, and importance of correct and rapid identification for a successful treatment and lower risk of morbidity and mortality. (AU)