Experiences of antibiotic use among Brazilian healthcare users: An exploratory study.

INTRODUCTION: This article analyzes experiences of antibiotic use and bacterial infections among Primary Health Care users of the Brazilian Unified Health System (SUS) and the possible implications for antimicrobial resistance (AMR). The aim is to map aspects that shape users' lay knowledge regarding antibiotics use and AMR. METHODS: This is an exploratory study, which consists primarily of individual in-depth interviews with 19 respondents. Recurrent interview topics were coded and analysed according to thematic content analysis. RESULTS: Our findings show users' lived experiences constitute three dimensions related to users' previous antibiotic use: (1) lay knowledge about medicines; (2) previous bacterial infections and (3) communication during the consultation. Lay knowledge encompasses the users' understanding of how antibiotics work in comparison to other drugs and experimentations they make with medication. Users' narratives about bacterial infections are divided into situations of urinary tract infections and antibiotic treatments for other conditions. Communication during the consultation is mainly characterized by a lack of shared knowledge and trust in the doctor-patient relationship. DISCUSSION: Users bring together knowledge learned from their own experiences to create the rationale, which shapes how they understand antibiotic use, bacterial infections and medical advice. These experiences are interwoven with information received from healthcare professionals (HPs) on these topics, creating a scenario that goes beyond professional information about antibiotic use. Users have knowledge about medication, antibiotics use and bacterial infection but do not have room to share it with HP, allowing lived experiences to take precedence over professional information. CONCLUSION: Users ascribe symbolic meanings to antibiotics creating a lay knowledge frame, even if this knowledge is not scientifically correct. The personal experiences of bacterial infections and their treatment are also an important source of knowledge about antibiotic use and AMR among users. Users demand from their HPs both trust and willingness to listen to their health narratives and experiences. By considering lay knowledge as part of the assessment of a user's health condition, rather than dismissing it as erroneous and therefore unworthy of attention, HPs may enhance the compliance of users. PATIENT OR PUBLIC CONTRIBUTION: Patients or community members did not participate in the design stage of the study. Primary Care patients were invited to participate as respondents of in-depth interviews, which were carried out by the first author at a Primary Care Unit (PCU) in the suburb of Campo Limpo, Southern region of São Paulo, Brazil. Patients were interviewed after reading and signing a Free and Informed Consent Form, holding with them a copy of the Form. Among the final activities of the project, a feedback session at the same PCU is planned to report on the results of the study. All respondents will have the opportunity to contribute further information regarding their antibiotic use and exchange knowledge and experiences on antimicrobial resistance.

PKA-mediated effect of MAS receptor in counteracting angiotensin II-stimulated renal Na+-ATPase.

We showed previously that angiotensin-(1-7) [Ang-(1-7)] reversed stimulation of proximal tubule Na+-ATPase promoted by angiotensin II (Ang II) through a D-ala(7)-Ang-(1-7) (A779)-sensitive receptor. Here we investigated the signaling pathway coupled to this receptor. According to our data, Ang-(1-7) produces a MAS-mediated reversal of Ang II-stimulated Na+-ATPase by a Gs/PKA pathway because: (1) the Ang-(1-7) effect is reversed by GDPbetaS, an inhibitor of trimeric G protein and Gs polyclonal antibody. Cholera toxin, an activator of Gs protein, mimicked it; (2) in the presence of Ang II, Ang-(1-7) increased the PKA activity 10-fold; (3) the peptide inhibitor of PKA blocked the Ang-(1-7) effect on Ang II-stimulated Na+-ATPase; (4) Ang-(1-7) reverses the Ang II-stimulated PKC activity; (5) cAMP mimicked the Ang-(1-7) effect on the Ang II-stimulated Na+-ATPase. Our results provide new understanding about the signaling mechanisms coupled to MAS receptor-mediated renal Ang-(1-7) effects.

The angiotensin receptor type 1-Gq protein-phosphatidyl inositol phospholipase Cbeta-protein kinase C pathway is involved in activation of proximal tubule Na+-ATPase activity by angiotensin(1-7) in pig kidneys.

In a previous study, we observed that angiotensin(1-7) (Ang(1-7)) stimulates proximal tubule Na+-ATPase activity through the angiotensin receptor type 1 (AT1R). Here we aimed to study the signalling pathways involved. Our results show that the stimulatory effect of Ang(1-7) on Na+-ATPase activity through AT1R involves a Gq protein-phosphatidyl inositol-phospholipase Cbeta (PI-PLCbeta) pathway because: (1) the effect was reversed by GDPbetaS, a non-hydrolysable GDP analogue, and by a monoclonal Gq protein antibody; (2) the effect was similar and not additive to that of GTPgammaS, a non-hydrolysable GTP analogue; (3) Ang(1-7) induced a rapid decrease (30 s) in phosphatidylinositol 4,5-bisphosphate levels, a PI-PLCbeta substrate; and (4) U73122, a specific inhibitor of PI-PLCbeta, abolished Ang(1-7)-induced stimulation of Na+-ATPase activity. Angiotensin(1-7) increased the protein kinase C (PKC) activity similarly to phorbol-12-myristate-13-acetate (PMA), an activator of PKC. This effect was reversed by losartan, a specific antagonist of AT1R. The stimulatory effects of Ang(1-7) and PMA on Na+-ATPase activity are similar, non-additive and reversed by calphostin C, a specific inhibitor of PKC. A catalytic subunit of PKC (PKC-M) increased the Na+-ATPase activity. These data show that Ang(1-7) stimulates Na+-ATPase activity through the AT1R-Gq protein-PI-PLCbeta-PKC pathway. This effect is similar to that described for angiotensin II, showing for the first time that these compounds could have similar effects in the renal system.

Angiotensin-(1-7) reverts the stimulatory effect of angiotensin II on the proximal tubule Na(+)-ATPase activity via a A779-sensitive receptor.

Recently, we demonstrated that the stimulatory effect of Ang II on the Na(+)-ATPase activity in proximal tubules is reversed, in a dose-dependent manner, by Ang-(1-7) [Biochim. Biophys. Acta 1467 (2000) 189]. In the present paper, we characterized the receptor involved in this phenomenon. The preincubation of the Na(+)-ATPase with 10(-8) M Ang II increases the enzyme activity from 7.50+/-0.02 (control) to 12.40+/-1.50 nmol Pi mg(-1) min(-1) (p<0.05). Addition of 10(-9) M Ang-(1-7) completely reverts this effect returning the ATPase activity to the control level. This effect seems to be specific to Ang-(1-7) since Ang III (10(-12)-10(-8) M) does not modify the stimulation of the renal proximal tubule Na(+)-ATPase activity by Ang II. Saralasin abolishes the Ang-(1-7) effect in a dose-dependent manner being the maximal effect obtained at 10(-11) M. The increase in A779 concentration (from 10(-12) to 10(-7) M), a specific Ang-(1-7) antagonist, also abolishes the Ang-(1-7) effect. On the other hand, PD123319 (10(-8)-10(-6) M), an AT(2) antagonist receptor, and losartan (10(-12)-10(-7) M), an AT(1) antagonist receptor, does not modify the effect of Ang-(1-7). Taken together, these data indicate that Ang-(1-7) reverts the stimulatory effect of Ang II on the Na(+)-ATPase activity in proximal tubule through a A779-sensitive receptor.