Aim The current study was conducted to determine the antimicrobial resistance profile and genetic relatedness of Aeromonas sp. isolated from healthcare and urban effluents, wastewater treatment plant (WWTP) and river water. Methods and Results We detected the presence of genes conferring resistance to β‐lactam, quinolone and aminoglycoside. Multilocus sequence typing was carried out to differentiate the strains, and multilocus phylogenetic analysis was used to identify the species. A total of 28 cefotaxime‐resistant Aeromonas sp. strains were identified, harbouring uncommon Guiana‐extended‐spectrum (GES)‐type β‐lactamases (GES‐1, GES‐5, GES‐7 and GES‐16). Multidrug‐resistant Aeromonas sp. were found in hospital wastewater, WWTP and sanitary effluent, and A. caviae was identified as the most prevalent species (85·7%). Conclusion The release of untreated healthcare effluents, presence of antimicrobials in the environment, in addition to multidrug‐resistant Aeromonas sp., are all potential factors for the spread of resistance. Significance and Impact of the Study We identified a vast repertoire of antimicrobial resistance genes (ARG) in Aeromonas sp. from diverse aquatic ecosystems, including those that encode enzymes degrading broad‐spectrum antimicrobials widely used to treat healthcare‐associated infections. Hospital and sanitary effluents serve as potential sources of bacteria harbouring ARG and are a threat to public health.

BackgroundSmall‐colony variants (SCVs) are a morphologic subtype of Staphylococcus aureus that may occur through several mechanisms including auxotrophism for thymidine, hemin, or menadione. Auxotrophic SCV for thymidine fail to synthesize DNA specifically because of mutations in the thymidylate synthase gene. We isolated S. aureus thymidine‐dependent SCVs (TD‐SCV) from blood and respiratory samples of a pediatric patient with cystic fibrosis and pulmonary exacerbation.MethodsNutritional dependence of SCVs on hemin, menadione, and thymidine was evaluated. Antimicrobial susceptibility testing was performed through broth microdilution. Polymerase chain reaction was carried out for mecA, ermA, ermB, ermC, msrA, and msrB resistance genes. DNA sequencing was used to determine mutations in thyA and the multilocus sequence typing to identify genetic relatedness.ResultsMethicillin‐sensitive S. aureus with normal and TD‐SCV phenotypes were isolated from respiratory samples and a TD‐SCV phenotype was isolated from blood culture. Macrolides resistance was attributed to ermC and msrB genes. All isolates belonged to ST398. The thyA gene in S. aureus is 957 nucleotides in length and encodes a protein of 318 amino acids. The TD‐SCV isolates carried a −2 nt frameshift mutation (delta 667GC668) in thyA, creating a stop codon at residue 222 close to the predicted binding site for deoxyuridine monophosphate.ConclusionsThe pathogenesis of SCVs is complex and not fully elucidated. Factors inherent to the patient such as physiological conditions, recurrent infections, or coinfection should be considered. Although SCVs are considered less virulent, they showed the ability to invade and cause bacteremia in the patient.

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.

Similar findings have not yet been reported in Brazil, emphasizing the importance of monitoring small-colony variants (SCVs). Altogether, our results highlight the need to improve detection methods and review antimicrobial therapy protocols in cystic fibrosis (CF) patients.