Abstract
Background: The increasing prevalence of antimicrobial resistance among Gram-
negative bacteria has raised global concerns due to its severe implications, including the
emergence of untreatable and potentially fatal infections. Of particular concern is the
poultry industry, which has been identified as a major consumer of antimicrobials,
including those considered as last-resort treatments for complicated multi-drug resistant
Gram-negative infections.
Methods: A total of ninety cloacal swabs were acquired from 30 poultry farms located
across Nablus governorate between March and June 2019. These swabs, obtained
specifically from broilers, were subjected to cultivation on suitable culture media and
under optimal conditions to isolate Gram-negative bacteria. Subsequently, the isolated
bacteria underwent microbiological procedures, including Gram staining, oxidase testing,
and API20E, to facilitate their identification. The susceptibility of these isolates to 16
antibiotics was assessed using the disk diffusion method, with the exception of colistin,
which was evaluated through micro-broth dilution. Furthermore, molecular
characterization was performed using PCR to detect the presence of mcr genes.
Result: A total of 244 Gram negative bacterial isolates were obtained, characterized,
identified and grouped under two categories: 1- Enterobacteriaceae (170 isolates (69.7
%)), 2- others (74 isolates (30.3%)). The first group included 103 Escherichia coli (42.2
%), 24 Proteus mirabilis (9.8 %) and 19 Salmonella spp. (7.8 %). The second group
contained 62 Serratia spp. (25.4 %), 1 Aeromonas hydrophila (0.4 %) and 11 other non-
identified (4.51%). The Highest antibiotic resistance was recorded against trimethoprim
(100 %), tetracycline (94.3%), followed by trimethoprim-sulphamethoxazol (90.6%),
ciprofloxacin (86.1 %), chloramphenicol (80.7 %), ampicillin (75.4 %), gentamicin (50.4
%), fosfomycin (17.2 %), cefuroxime (10.2 %), cefotaxime (10.2 %), ceftriaxone (7 %),
cefazidime (2 %), amikacin (1.2 %) and meropenem (0.4 %). Moreover, the proportions
of multidrug-resistant (MDR), extensively drug-resistant (XDR) and Extended-spectrum
beta-lactamase (ESBL) isolates among our isolates were 140/167(84%), 8/167(5%) and
31/167(19%) respectively. Interestingly, 65.4 % of the overall isolated bacteria were
resistant to colistin when using micro-broth dilution method. Among Enterobacteriaceae
isolated in our study, 111/167 (66.5%) were resistant to colistin, accordingly mcr gene
variants were detected in 35/111 (32%) of the isolates. The most frequent gene variant in
our isolates is mcr-7, which was detected in 12 isolates. Then, mcr-1 and mcr-8 which
were found in 10 and 8 isolates respectively.
Conclusion: To the best of our knowledge, this is the first study reporting antimicrobial
susceptibility testing especially for colistin resistance in Gram negative bacteria isolated
from poultry farms in West Bank, Palestine. Our finding triggers an alert to colistin
resistance in animal farms, mainly poultry, and its dire consequences on human health.

العنوان

Palestinian Medical and Pharmaceutical Journal (Pal. Med. Pharm. J.)

الناشر

An-Najah National University

بلد الناشر

فلسطين

Indexing

Scopus

معامل التأثير

None

نوع المنشور

إلكتروني فقط

المجلد

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السنة

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الصفحات

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