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

bacterial cells and the acridine orange were selected, and Table 2. Isolation of Pseudomonas aeruginosa and
a loopful of the test organism in the tube(s) was streaked distribution of MBL genes
aseptically on MacConkey agar (MCA) plate(s) and CSA Distribution n (/%)
plates, which served as the recovery medium. Incubation
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was done overnight at 37°C in the incubator, and resultant Source Poultry
colonies were subcultured onto freshly prepared MCA and Number of samples analyzed 65
CSA plates to get pure strains of P. aeruginosa. Colonies of Number of bacteria isolated 36 (55.5)
P. aeruginosa that emanated from the recovery plates were Phenotypic MBL detection 23 (63.9)
checked for the loss of antibiotic resistance determinants bla NDM -
(genes) by investigating their susceptibility profile to bla 11 (47.8)
any of the carbapenems (IPM or ETP) and their MBL bla IMP‑1 -
production ability using the MHT technique. The carriage VIM
of the antibiotic-resistant genes (ARGs) on the plasmid bla IMP‑2 6 (26.1)
was confirmed in P. aeruginosa isolates that showed Abbreviation: MBL: Metallo-beta-lactamase.
susceptibility to previously ineffective antibiotics (IPM,
ETP, or others) and was confirmed as non-MBL producers
by the MHT technique.
2.7. Multiple antibiotic resistance index (MARI)
The MARI of the resistant P. aeruginosa isolates was
determined according to a previously used protocol using
the MARI formula. Equation I was used to calculate the
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MARI for multidrug resistance profiling.
Number of antibiotics to which
resistence occured
MARI= (I)
Total number of antibiotics to which the
Pseudomonas aeruginosa isolates were tested

3. Results Figure 1. Percentage of antibiotic susceptibility and resistance to
Pseudomonas aeruginosa.
This study investigated antimicrobial susceptibility
patterns in Pseudomonas-producing MBLs from poultry
milieus in Enugu, Nigeria. Of the 65 cloacal swab samples
bacteriologically analyzed for the isolation of Pseudomonas,
36 isolates of P. aeruginosa (55.4%) were successfully
recovered from cetrimide-selective agar plates (Table 2).
The results of the antimicrobial susceptibility testing
of the 48 isolates of P. aeruginosa in this study are shown
in Figure 1. The P. aeruginosa isolates showed high levels Figure 2. Gel picture of MBL gene amplification. Lane M is the positive
of resistance to the tested antibiotics, particularly CTX control (100 bp), while lanes 1 – 9 are the test samples of DNA products
(77.8%), IPM (69.4%), CN (63.9%), AK (58.3%), FOS from Pseudomonas aeruginosa isolates. Lane 5 is an amplified DNA product
(55.5%), CIP (66.7%), TE (75%), ETP (55.5%), SXT indicative of the bla IMP-1 MBL gene. Lane 9 was used as the negative control.
(66.7%), and FOX (52.8%). Our results indicated that Abbreviation: MBL: Metallo-beta-lactamase.
P. aeruginosa was multiply resistant, as over 50% of the
isolates showed multiple resistance to antibiotics in more These isolates were phenotypically subjected to the
than three classes. Multiple drug resistances were recorded MHT protocol to detect MBLs phenotypically. In this
in the antibiotic classes of cephalosporins, carbapenems, study, Pseudomonas showed a high level of resistance to
and aminoglycosides against the isolated P. aeruginosa IPM and ETP, which are important antibiotics that are
isolates from poultry milieus investigated in this study. clinically used for the treatment of bacterial infections

Volume 1 Issue 1 (2024) 63 doi: 10.36922/mi.2319