Banca de QUALIFICAÇÃO: EMMANOELLY ADRIANA DO NASCIMENTO TRIESTE

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : EMMANOELLY ADRIANA DO NASCIMENTO TRIESTE
DATE: 12/12/2025
TIME: 14:00
LOCAL: Google Meet https://meet.google.com/xvr-zuev- nmb
TITLE:

MANGROVES AS A RESERVOIR OF RESISTANT MICROORGANISMS: A ONE HEALTH
ALERT

 

KEY WORDS:

Antimicrobial resistance, Bacterial resistance, Antifungals

PAGES: 85
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUMMARY:

Mangroves are coastal wetlands that are home to intensive anthropogenic activities,
including aquaculture. So, these ecosystems can be like reservoirs for
microorganisms that are resistant to antimicrobials, which is a potential risk to public
health. Given this, the objective of this study was to isolate and phenotypically
characterize resistant microorganisms present in water, soil, and oysters collected in
a mangrove located in Natal, Rio Grande do Norte. Samples were collected at two
specific points in the region known as Gamboa Manimbu, in the municipality of Natal,
Rio Grande do Norte. A total of ten samples were collected, always after a minimum
period of 48 hours of drought and covering the four seasons of the year. Two liters of
water (filtered through filter paper), the contents of macerated oysters, and 10 g of
previously diluted soil were collected. Each type of sample was cultured in peptone
water supplemented with specific antibiotics for 24 hours at 37 °C. Then, 0.1 mL
aliquots were seeded in MacConkey agar supplemented with colistin, cefotaxime, or
meropenem, Salted Mannitol Agar + oxacillin, M-Enterococcus Agar + vancomycin,
and CHROMagar Candida, all plates being incubated at 37 °C for 48 hours. The
colonies obtained were identified by MALDI-TOF. Subsequently, the isolates were
submitted to antimicrobial susceptibility testing by the disk diffusion method and
phenotypic testing interpreted according to BrCast recommendations. A total of 243
microorganisms were isolated, of which 214 (88.1%) were bacteria and 35 (11.9%)
were yeasts. Among the bacterial isolates, there was a predominance of Gram-
negative bacilli (n = 151) and Gram-positive cocci belonging to the genus
Enterococcus spp. (n = 12; 7.4%). Among the Gram-negative bacilli, 91 non-
fermenting isolates (55.8%) and 60 isolates (36.8%) belonging to the order
Enterobacterales were obtained. Sensitivity tests identified eight Escherichia coli and
four Klebsiella pneumoniae with a profile suggestive of extended-spectrum beta-
lactamase (ESBL) production, confirmed by the approximate disc test. In addition,
two isolates of K. pneumoniae producing AmpC cephalosporinase and NDM
carbapenemase were detected, confirmed by inhibitor tests and
immunochromatographic testing, respectively. The plate dilution test also showed
that five E. coli isolates were resistant to colistin. Among the yeasts analyzed, two
isolates of Pichia kudriavzevii showed resistance to caspofungin and tebuconazole,
while two isolates of Meyerozyma guilliermondii showed resistance to tebuconazole.
The results demonstrate that the mangrove studied represents a potential reservoir
of resistant microorganisms, reinforcing the need for continuous monitoring of this
ecosystem and preventive actions aimed at environmental and public health.

 

COMMITTEE MEMBERS:
Presidente - 1143204 - RAFAEL WESLEY BASTOS
Externa à Instituição - QUÉZIA MOURA DA SILVA - UFES
Externa à Instituição - SILVIA HELENA SOUSA PIETRA PEDROSO - UFPE