Emerging threat: Antimicrobial resistance proliferation during epidemics - A case study of the SARS-CoV-2 pandemic in South Brazil

The escalating global concern of antimicrobial resistance poses a significant challenge to public health. This study delved into the occurrence of resistant bacteria and antimicrobial resistance genes in the waters and sediments of urban rivers and correlated this emergence and the heightened use of antimicrobials during the COVID-19 pandemic. Isolating 45 antimicrobial-resistant bacteria across 11 different species, the study identifies prevalent resistance patterns, with ceftriaxone resistance observed in 18 isolates and ciprofloxacin resistance observed in 13 isolates. The detection of extended-spectrum β-lactamases, carbapenemases, and acquired quinolone resistance genes in all samples underscores the gravity of the situation. Comparison with a pre-pandemic study conducted in the same rivers in 2019 reveals the emergence of previously undetected new resistant species, and the noteworthy presence of new resistant species and alterations in resistance profiles among existing species. Notably, antimicrobial concentrations in rivers increased during the pandemic, contributing significantly to the scenario of antimicrobial resistance observed in these rivers. We underscore the substantial impact of heightened antimicrobial usage during epidemics, such as COVID-19, on resistance in urban rivers. It provides valuable insights into the complex dynamics of antimicrobial resistance in environmental settings and calls for comprehensive approaches to combat this pressing global health issue, safeguarding both public and environmental health.

Colonization by multidrug-resistant bacteria in hematological patients undergoing hematopoietic stem cell transplantation and clinical outcomes: A single-center retrospective cohort study

BACKGROUND

Bloodstream infections are a leading cause of death in patients who undergo hematopoietic stem cell transplantation (HSCT) and are more severe when caused by multidrug-resistant (MDR) bacteria. This study proposed to investigate if colonization by MDR bacteria negatively affects the clinical outcomes in hematological patients after HSCT, as well as to evaluate possible risk factors for death due to bacteremia by the same colonizing agent.

METHODS

A single-center retrospective cohort study was conducted with 405 hematological patients submitted to a single HSCT procedure between 2015 and 2021. Patients were classified as colonized (n = 132) or noncolonized (n = 273) based on the surveillance cultures from D-30 to D+30 of transplantation, and their relevant clinical and laboratory data were collected until D+100.

RESULTS

Colonization by MDR bacteria increased blood culture positivity by all micro-organisms and also specifically by MDR bacteria, with a more pronounced effect when caused by carbapenemase-producing Klebsiella pneumoniae. Patients colonized with carbapenem-resistant K. pneumoniae had increased overall mortality (HR = 4.07, 95% CI 1.85-8.91, P = .0005) and had prolonged hospital length of stay in the context of autologous transplantation. Risk factors for death due to bacteremia by the same colonizing agent were neutropenia, colonization by carbapenem-resistant K. pneumoniae and use of high-dose total body irradiation in conditioning.

CONCLUSION

Hematological patients colonized by MDR bacteria presented a higher incidence of bloodstream infections, and colonization by carbapenemase-producing K. pneumoniae was associated with reduced overall survival.

The Xpert® MTB/RIF diagnostic test for pulmonary and extrapulmonary tuberculosis in immunocompetent and immunocompromised patients: Benefits and experiences over 2 years in different clinical contexts

Xpert^® MTB/RIF has been widely used for tuberculosis (TB) diagnosis in Brazil, since 2014. This prospective observational study aimed to evaluate the performance of Xpert in different contexts during a two-year period: (i) laboratory and clinical/epidemiological diagnosis; (ii) HIV-positive and -negative populations; (iii) type of specimens: pulmonary and extrapulmonary. Overall, 924 specimens from 743 patients were evaluated. The performance of the assays was evaluated considering culture (Lowenstein Jensen or LJ medium) results and composite reference standard (CRS) classification as gold standard. According to CRS evaluation, 219 cases (29.5%) were classified as positive cases, 157 (21.1%) as ‘possible TB’, and 367 (49.3%) as ‘not TB’. Based on culture, Xpert and AFB smear achieved a sensitivity of 96% and 62%, respectively, while based on CRS, the sensitivities of Xpert, AFB smear, and culture were 40.7%, 20%, and 25%, respectively. The pooled sensitivity and specificity of Xpert were 96% and 94%, respectively. Metric evaluations were similar between pulmonary and extrapulmonary samples against culture, whereas compared to CRS, the sensitivities were 44.6% and 29.3% for the pulmonary and extrapulmonary cases, respectively. The Xpert detected 42/69 (60.9%) patients with confirmed TB and negative culture on LJ medium, and 52/69 (75.4%) patients with negative AFB smear results. There was no significant difference in the diagnostic accuracy based on the types of specimens and population (positive- and negative-HIV). Molecular testing detected 13 cases of TB in culture-negative patients with severe immunosuppression. Resistance to rifampicin was detected in seven samples. Herein, Xpert showed improved detection of pulmonary and extrapulmonary TB cases, both among HIV-positive and -negative patients, even in cases with advanced immunosuppression, thereby performing better than multiple other diagnostic parameters.