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Updated: May 3, 2026
Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
Published on: March 3, 2023
Multi-drug resistant gram-negative enteric bacteria isolated from flies at Chengdu Airport, China
Yang Liu1, Yu Yang2, Feng Zhao2
1College of Life Science, Sichuan University, Chengdu, People's Republic of China.
Abstract:
We collected flies from Chengdu Shuangliu International Airport to examine for the presence of bacteria and to determine the sensitivity patterns of those bacteria. A total of 1,228 flies were collected from 6 sites around Chengdu Shuangliu International Airport from April to September 2011. The predominant species was Chrysomya megacephala (n=276, 22.5%). Antimicrobial-resistant gram-negative enteric bacteria (n=48) were isolated from flies using MacConkey agar supplemented with cephalothin (20 microg/ml). These were identified as Escherichia coli (n=37), Klebsiella pneumoniae (n=6), Pseudomonas aeruginosa (n=3) and Aeromonas hydrophila (n=2). All isolated bacteria were tested for resistance to 21 commonly used antimicrobials: amoxicillin (100%), ticarcillin (100%), cephalothin (100%), cefuroxime (100%), ceftazidime 1 (93.8%), piperacillin (93.8%), cefotaxime (89.6%), ticarcillin-clavulanate (81.3%), trimethoprim-sulfamethoxazole (62.5%), ciprofloxacin (54.2%), gentamicin (45.8%), cefepime (39.6%), tobramycin (39.6%), ceftazidime (22.9%), cefoxitin (16.7%), amikacin (16.7%), netilmicin (14.6%), amoxicillin-clavulanate (6.3%) and piperacillin-tazobactam (2.1%). No resistance to meropenem or imipenem was observed. Antibiotic resistance genes among the isolated bacteria were analyzed for by polymerase chain reaction. Thirty of the 48 bacteria with resistance (62.5%) possessed the blaTEM gene.
Insights
Flies collected at Chengdu Shuangliu International Airport harbored antimicrobial-resistant bacteria, primarily Escherichia coli. Most resistant isolates carried the blaTEM gene, indicating potential public health risks.
Area of Science:
- Medical Microbiology
- Public Health
- Environmental Microbiology
Background:
- Airport environments can serve as reservoirs for pathogenic bacteria.
- Insect vectors, such as flies, may contribute to the dissemination of antimicrobial resistance.
Purpose of the Study:
- To investigate the prevalence of bacteria in flies from Chengdu Shuangliu International Airport.
- To determine the antimicrobial susceptibility patterns of isolated bacteria.
- To identify antibiotic resistance genes in resistant bacterial isolates.
Main Methods:
- Collection of 1,228 flies from six sites around the airport.
- Isolation of antimicrobial-resistant gram-negative enteric bacteria using MacConkey agar with cephalothin.
- Identification of bacterial species and antimicrobial susceptibility testing against 21 agents.
- Detection of antibiotic resistance genes via polymerase chain reaction.
Main Results:
- Chrysomya megacephala was the predominant fly species.
- Forty-eight antimicrobial-resistant gram-negative enteric bacteria were isolated, including Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Aeromonas hydrophila.
- High resistance rates were observed for amoxicillin, ticarcillin, cephalothin, cefuroxime, and ceftazidime.
- No resistance was found to meropenem or imipenem.
- The blaTEM gene was detected in 62.5% of the resistant isolates.
Conclusions:
- Flies at Chengdu Shuangliu International Airport carry multidrug-resistant bacteria.
- The presence of the blaTEM gene highlights a significant public health concern.
- Airport hygiene and vector control are crucial for mitigating the spread of antibiotic resistance.
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