Distribution of Extended-Spectrum β-Lactamase (ESBL)-Encoding Genes among Multidrug-Resistant Gram-Negative Pathogens Collected from Three Different Countries

Abstract

The incidence of Extended-spectrum β-lactamase (ESBL)-encoding genes (bla_CTX-M and bla_TEM) among Gram-negative multidrug-resistant pathogens collected from three different countries was investigated. Two hundred and ninety-two clinical isolates were collected from Egypt (n = 90), Saudi Arabia (n = 162), and Sudan (n = 40). Based on the antimicrobial sensitivity against 20 antimicrobial agents from 11 antibiotic classes, the most resistant strains were selected and identified using the Vitek2 system and 16S rRNA gene sequence analysis. A total of 85.6% of the isolates were found to be resistant to more than three antibiotic classes. The ratios of the multidrug-resistant strains for Egypt, Saudi Arabia, and Sudan were 74.4%, 90.1%, and 97.5%, respectively. Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa showed inconstant resistance levels to the different classes of antibiotics. Escherichia coli and Klebsiella pneumoniae had the highest levels of resistance against macrolides followed by penicillins and cephalosporin, while Pseudomonas aeruginosa was most resistant to penicillins followed by classes that varied among different countries. The isolates were positive for the presence of the bla_CTX-M and bla_TEM genes. The bla_CTX-M gene was the predominant gene in all isolates (100%), while bla_TEM was detected in 66.7% of the selected isolates. This work highlights the detection of multidrug-resistant bacteria and resistant genes among different countries. We suggest that the medical authorities urgently implement antimicrobial surveillance plans and infection control policies for early detection and effective prevention of the rapid spread of these pathogens.

Keywords: antimicrobial resistance; clinical samples; different countries; multidrug-resistant pathogens; resistant-genes.

Figure 1

Percentages of pathogenic strains isolated from various clinical samples (collected from three different countries: Egypt, Saudi Arabia, and Sudan) among all isolates identified and the distribution of strains in each country (modified from Azab et al., [15]).

Figure 2

The percentage of strains resistant to antimicrobial agents from 11 antibiotic classes of the 292 bacterial strains obtained from clinical specimens: 0 means not resistant to any antibiotic group (sensitive to all groups); 1–10 indicate the numbers of classes to which the bacterial strains showed resistance; 1 indicates the percentage of strains that were resistant to only one class of antibiotic; 2 indicates the percentage of strains that were resistant to two classes of antibiotics, etc.

Figure 3

The percentages of strains resistant to antimicrobial agents from 11 antibiotic classes from all bacterial strains isolated from Egypt, Sudan, and Saudi Arabia: 0 means the percentage of strains obtained from a country that were not resistant to any antibiotic group (sensitive to all groups); numbers 1–10 indicate the numbers of classes that the bacterial strains showed resistance to; 1 indicates the percentage of strains obtained from this country that showed resistance to only one class of antibiotic; 2 indicates the percentage of strains obtained from a country that showed resistance to two classes of antibiotics amongst the 11 well known antibiotic classes, etc.

Figure 4

The percentage specific bacterial species that were resistant to antimicrobial agents from 11 antibiotic classes among isolated strains of the same species (obtained from 3 different countries: Egypt, Sudan, and Saudi Arabia): 0 means the percentage of strains that were not resistant to any antibiotic group (sensitive to all groups); numbers 1–10 indicate the numbers of classes to which the bacterial strain showed resistance; 1 indicates the percentage of strains that showed resistance to only one class of antibiotic; 2 indicates the percentage of strains that showed resistance to two classes of antibiotics amongst the 11 well known antibiotic classes, etc.

Figure 5

A phylogenetic tree based on 16S rRNA gene sequencing for the Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae strains.

Figure 6

The presence of bla_CTX-M and bla_TEM genes. bla_CTX-M genes in multidrug-resistant isolates obtained from three different countries are shown. The DNA ladder is 50 bp and the bla_TEM gene (size 600 bp) was found in most of the selected isolates (n = 4); it was not detected in E. coli and K. pneumoniae strains obtained from Saudi Arabia and Egypt, respectively. The bla_CTX-M gene (size 500 bp) was found in all selected isolates (n = 6). The bla_CTX-M gene was detected in E. coli and K. pneumoniae obtained from the three countries included in this study; 1, 2, and 5 are codes for the selected E coli strains from Saudi Arabia, Egypt, and Sudan, respectively; 3, 4, and 6 are codes for the selected K. pneumoniae strains from Egypt, Saudi Arabia, and Sudan, respectively.