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Microbes & Immunity Food chain milieus as a reserver for multidrug resistance

were multidrug resistant (50%) and carried plasmids, indicating horizontal transmission of resistance genes. Genes
for bacterial resistance can be transmitted through mobile genetic elements. Therefore, sustainable interventions are
needed to mitigate antibiotic use in poultry practices in Nigeria to curb the development of MBL-producing bacteria
arising from selective (antibiotic) pressures in such an environment. These interventions can help to detect and stop
infections caused by resistant bacteria before they become clinical cases in our hospitals.

Keywords: Bacterial resistance; Metallo-beta-lactamase-producing bacteria; Pseudomonas; Susceptibility testing; One health

1. Introduction reports suggest that aztreonam (a monobactam) has good
activity against the enzyme in vitro. 9,10
Food chain milieus, such as poultry and others, are multi-
stressed environments for the silent development and The prevalence of bacteria-producing MBLs is
11
transmission of antibiotic-resistant bacteria and genes. gradually growing globally. Moreover, bacterial strains
Antibiotic resistance is rapidly eroding the efficacy of our such as Pseudomonas aeruginosa harboring plasmids
antibiotic armamentarium globally. Most problems of (extra-chromosomal DNA that allows transmission of
antibiotic resistance occur in the hospital environment, genetic materials including resistance genes between
where antibiotics are usually used heavily for the bacteria species) that mediate MBL production could
treatment and management of infectious diseases. worsen the antibiotic crisis by allowing MBL genes to be
1-4
Nonetheless, this trend is not usually the case, as some easily transmitted between bacteria genera and species
other cases of antibiotic resistance have been previously in a particular environment (e.g., poultry milieus).
reported in the general environment, including abattoirs, Pseudomonas is a notable nosocomial pathogen that
poultry, livestock, and animal husbandry, where shows reduced susceptibility patterns to available
antibiotics, particularly those used in clinical medicine, antibiotics. Plasmid-mediated strains of MBL-producing
are also used as prophylaxis and for promoting animal P. aeruginosa from poultry milieus portend a public health
growth. Antibiotics are usually used at sub-inhibitory menace due to the transmissibility of their antibiotic
5-8
concentrations in non-clinical practices, such as poultry resistance genes (ARGs) to other bacteria species through
and livestock production. In such scenarios, the antibiotic plasmids. Furthermore, strains of P. aeruginosa that
only kills susceptible bacteria and allows other resistant produces MBLs are known to be multidrug resistant
strains (that survive its antimicrobial onslaught) to go on and show reduced susceptibility to carbapenems, which
thriving and thus become resistant to the same antibiotic are critically important antibiotics used as a last line of
later. Antibiotic-resistant bacteria can spread to humans defense against multidrug-resistant bacterial infections.
8,9
from animals and poultry birds, as well as from human- Thus, the mitigation of antibiotic resistance in the general
to-human contact; they can also spread from raw food environment, especially in the food chain sectors such as
and from the environment into the human population poultry, will help stop its evolution and spread, as well as
and vice versa. 3,5,7 One such resistance phenotype that has help ensure a sustainable environment in terms of safer
emerged following incessant applications of antibiotics (in foods and water for all. The current study is the first report
farms as growth promoters or food supplements) in animal of plasmid-mediated P. aeruginosa that produced MBL in a
husbandry and livestock production and that can spread food chain milieu in Enugu, Nigeria.
from animals to humans through contact or consumption
is carbapenemases like metallo-beta-lactamases (MBLs). 2. Methods
MBLs are carbapenemases that confer bacterial resistance 2.1. Sampling protocol
to carbapenems (e.g., imipenem [IPM]). MBLs could
1,9
be found in both enteric and non-enteric bacteria, like This study was approved by the Committee on Ethics
Pseudomonas. The presence of bacteria that produce MBLs and Research, Enugu State University of Science and
9
in farm settings could result in infections that could prove Technology, Nigeria. A total of 65 cloacal swab samples
difficult to treat in the hospital. This is because bacteria- were aseptically collected with the informed (verbal)
producing MBLs are multidrug resistant and can cause consent of the poultry farmers from poultry birds in
resistance to non-carbapenem agents. MBL-producing three poultry farms in Enugu, Nigeria, for this study. All
8
bacteria could confer resistance to antibacterial agents samples were labeled and transported to the laboratory for
from different classes, thereby limiting treatment options. bacteriological investigation using standard microbiology
While MBL can hydrolyze all beta-lactam drugs, previous techniques.

Volume 1 Issue 1 (2024) 61 doi: 10.36922/mi.2319