Detection of metallo-beta-lactamase-producing genes blaSPM and blaNDM in Pseudomonas aeruginosa isolated from wastewater in Southern Brazil.

Pseudomonas aeruginosa is commonly associated with the ability to acquire antimicrobial resistance. The surveillance of resistance genes in various environmental matrices has gained prominence in recent years, being seen as a potential threat to public health. The objective of this study was to investigate genes encoding metallo-beta-lactamases (MBLs), which confer resistance to carbapenems, in wastewater. Fifteen isolates of P. aeruginosa were collected for five months from samples obtained from a municipal wastewater treatment plant in Rio Grande do Sul. These isolates were subjected to disk diffusion testing using 10 different antimicrobials. Phenotypic enzymatic tests for MBLs were conducted, and positive isolates underwent DNA extraction and gene detection using the polymerase chain reaction. The resistance rate to ceftazidime was 100%, cefepime 73.3%, piperacillin-tazobactam 66.67%, imipenem 53.30%, levofloxacin 46.67%, tobramycin 40%, and ciprofloxacin and amikacin 13.33%. Both meropenem and aztreonam resistances were rare accounting for 6.60% of the tested isolates. Among these isolates, 20% were classified as multidrug-resistant and were found to carry the blaNDM and blaSPM genes. The results suggest that evaluating resistance genes in bacteria from urban raw sewage can provide data that assist in surveillance, as this environment can stimulate increased bacterial resistance.

Laronidase-loaded liposomes reach the brain and other hard-to-treat organs after noninvasive nasal administration.

Mucopolysaccharidosis type I (MPS I) is caused by a lack of the lysosomal enzyme α-L-iduronidase (IDUA), responsible for the degradation of the glycosaminoglycans (GAGs) dermatan and heparan sulfate, leading to multisystemic signs and symptoms. Enzyme replacement therapy (ERT) is a treatment that consists of weekly intravenous administrations of laronidase, a recombinant version of IDUA. However, ERT has limited access to certain tissues, such as bone, cartilage, and brain, and laronidase fails to trespass the BBB. In this sense, this study reports the development and characterization of laronidase-loaded liposomes for the treatment of MPS I mice. Liposomal complexes were obtained by the thin film formation method followed by microfluidization. The main characterization results showed mean vesicle size of 103.0 ± 3.3 nm, monodisperse populations of vesicles, zeta potential around + 30.0 ± 2.1 mV, and mucoadhesion strength of 5.69 ± 0.14 mN. Treatment of MPS I mice fibroblasts showed significant increase in enzyme activity. Nasal administration of complexes to MPS I mice resulted in significant increase in laronidase activity in the brain cortex, heart, lungs, kidneys, eyes, and serum. The overall results demonstrate the feasibility of nasal administration of laronidase-loaded liposomes to deliver enzyme in difficult-to-reach tissues, circumventing ERT issues and bringing hope as a potential treatment for MPS I.