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Isolation and Characterization of NDM-Positive Escherichia coli from Municipal Wastewater in Jeddah, Saudi Arabia

View Article: PubMed Central - PubMed

ABSTRACT

The emergence of resistance to last-resort antibiotics is a public health concern of global scale. Besides direct person-to-person propagation, environmental pathways might contribute to the dissemination of antibiotic-resistant bacteria and antibiotic resistance genes (ARGs). Here, we describe the incidence of blaNDM-1, a gene conferring resistance to carbapenems, in the wastewater of the city of Jeddah, Saudi Arabia, over a 1-year period. blaNDM-1 was detected at concentrations ranging from 104 to 105 copies/m3 of untreated wastewater during the entire monitoring period. These results indicate the ubiquity and high incidence of blaNDM-1 in the local wastewater. To track the bacteria carrying blaNDM-1, we isolated Escherichia coli PI7, a strain of sequence type 101 (ST101), from wastewater around the Hajj event in October 2013. Genome sequencing of this strain revealed an extensive repertoire of ARGs as well as virulence and invasive traits. These traits were further confirmed by antibiotic resistance profiling and in vitro cell internalization in HeLa cell cultures. Given that this strain remains viable even after a certain duration in the sewerage, and that Jeddah lacks a robust sanitary infrastructure to fully capture all generated sewage, the presence of this bacterium in the untreated wastewater represents a potential hazard to the local public health. To the best of our knowledge, this is the first report of a blaNDM-1-positive E. coli strain isolated from a nonnosocomial environment in Saudi Arabia and may set a priority concern for the need to establish improved surveillance for carbapenem-resistant E. coli in the country and nearby regions.

No MeSH data available.


In vitro internalization of E. coli PI7, DSM 1103, and DH5α in HeLa cell cultures. (a) Cell internalization of E. coli PI7 versus that of E. coli DSM 1103; (b) confocal microscopy of HeLa cell cultures infected with GFP-tagged E. coli PI7 and GFP-tagged E. coli DH5α (magnification, ×20); (c) z-stack of highlighted box in panel b corresponding to HeLa cells infected with E. coli PI7 (magnification, ×60). Asterisks highlight green fluorescent clusters.
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Figure 4: In vitro internalization of E. coli PI7, DSM 1103, and DH5α in HeLa cell cultures. (a) Cell internalization of E. coli PI7 versus that of E. coli DSM 1103; (b) confocal microscopy of HeLa cell cultures infected with GFP-tagged E. coli PI7 and GFP-tagged E. coli DH5α (magnification, ×20); (c) z-stack of highlighted box in panel b corresponding to HeLa cells infected with E. coli PI7 (magnification, ×60). Asterisks highlight green fluorescent clusters.

Mentions: As the genome sequencing revealed several pathogenicity traits associated with cell adhesion and invasion, E. coli PI7 was tested in vitro for its ability to internalize HeLa cells. A commensal strain of E. coli DSM 1103 was used for comparison, as genomic sequencing of this strain does not show traits for internalization (38). On average, 43% of the inoculated E. coli PI7 cells showed internalization into HeLa cells after 4 h of exposure (Fig. 4a). In addition, the confocal microscopy results confirmed that E. coli PI7 shows enhanced adhesion/internalization in HeLa cell cultures compared to the nonpathogenic control E. coli DH5α, which did not exhibit adhesion or internalization (Fig. 4b and c).


Isolation and Characterization of NDM-Positive Escherichia coli from Municipal Wastewater in Jeddah, Saudi Arabia
In vitro internalization of E. coli PI7, DSM 1103, and DH5α in HeLa cell cultures. (a) Cell internalization of E. coli PI7 versus that of E. coli DSM 1103; (b) confocal microscopy of HeLa cell cultures infected with GFP-tagged E. coli PI7 and GFP-tagged E. coli DH5α (magnification, ×20); (c) z-stack of highlighted box in panel b corresponding to HeLa cells infected with E. coli PI7 (magnification, ×60). Asterisks highlight green fluorescent clusters.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC4997845&req=5

Figure 4: In vitro internalization of E. coli PI7, DSM 1103, and DH5α in HeLa cell cultures. (a) Cell internalization of E. coli PI7 versus that of E. coli DSM 1103; (b) confocal microscopy of HeLa cell cultures infected with GFP-tagged E. coli PI7 and GFP-tagged E. coli DH5α (magnification, ×20); (c) z-stack of highlighted box in panel b corresponding to HeLa cells infected with E. coli PI7 (magnification, ×60). Asterisks highlight green fluorescent clusters.
Mentions: As the genome sequencing revealed several pathogenicity traits associated with cell adhesion and invasion, E. coli PI7 was tested in vitro for its ability to internalize HeLa cells. A commensal strain of E. coli DSM 1103 was used for comparison, as genomic sequencing of this strain does not show traits for internalization (38). On average, 43% of the inoculated E. coli PI7 cells showed internalization into HeLa cells after 4 h of exposure (Fig. 4a). In addition, the confocal microscopy results confirmed that E. coli PI7 shows enhanced adhesion/internalization in HeLa cell cultures compared to the nonpathogenic control E. coli DH5α, which did not exhibit adhesion or internalization (Fig. 4b and c).

View Article: PubMed Central - PubMed

ABSTRACT

The emergence of resistance to last-resort antibiotics is a public health concern of global scale. Besides direct person-to-person propagation, environmental pathways might contribute to the dissemination of antibiotic-resistant bacteria and antibiotic resistance genes (ARGs). Here, we describe the incidence of blaNDM-1, a gene conferring resistance to carbapenems, in the wastewater of the city of Jeddah, Saudi Arabia, over a 1-year period. blaNDM-1 was detected at concentrations ranging from 104 to 105 copies/m3 of untreated wastewater during the entire monitoring period. These results indicate the ubiquity and high incidence of blaNDM-1 in the local wastewater. To track the bacteria carrying blaNDM-1, we isolated Escherichia coli PI7, a strain of sequence type 101 (ST101), from wastewater around the Hajj event in October 2013. Genome sequencing of this strain revealed an extensive repertoire of ARGs as well as virulence and invasive traits. These traits were further confirmed by antibiotic resistance profiling and in vitro cell internalization in HeLa cell cultures. Given that this strain remains viable even after a certain duration in the sewerage, and that Jeddah lacks a robust sanitary infrastructure to fully capture all generated sewage, the presence of this bacterium in the untreated wastewater represents a potential hazard to the local public health. To the best of our knowledge, this is the first report of a blaNDM-1-positive E. coli strain isolated from a nonnosocomial environment in Saudi Arabia and may set a priority concern for the need to establish improved surveillance for carbapenem-resistant E. coli in the country and nearby regions.

No MeSH data available.