Virulence-determinants and antibiotic-resistance genes of MDR-E. coli isolated from secondary infections following FMD-outbreak in cattle

Abstract

This study aimed to evaluate the prevalence, multidrug-resistance traits, PCR-detection of virulence, and antibiotic-resistance genes of E. coli isolated from secondary infections following FMD-outbreak in cattle. A total of 160 random samples were gathered from private dairy farms in Damietta Province, Egypt. The specimens were subjected to bacteriological examination, serotyping, congo-red binding assay, antibiogram-testing, and PCR-monitoring of virulence-determinant genes (tsh, phoA, hly, eaeA, sta, and lt) as well as the antibiotic-resistance genes (bla_TEM, bla_KPC, and bla_CTX). The prevalence of E. coli was 30% (n = 48) distributed in 8 serogroups (40/48, 83.3%), while 8 isolates (8/48, 16.6%) were untypable. Besides, 83.3% of the examined isolates were positive for CR-binding. The tested strains harbored the virulence genes phoA, hly, tsh, eaeA, sta, and lt with a prevalence of 100% and 50%, 45.8%, 25%, 8.4%, and 6.2%, respectively. Furthermore, 50% of the recovered strains were multidrug-resistant (MDR) to penicillins, cephalosporins, and carbapenems, and are harboring the bla_TEM, bla_CTX, and bla_KPC genes. Moreover, 25% of the examined strains are resistant to penicillins, and cephalosporins, and are harboring the bla_TEM and bla_CTX genes. To the best of our knowledge, this is the first report concerning the E. coli secondary bacterial infections following the FMD-outbreak. The emergence of MDR strains is considered a public health threat and indicates complicated treatment and bad prognosis of infections caused by such strains. Colistin sulfate and levofloxacin have a promising in vitro activity against MDR-E. coli.

Figure 1

Prevalence of E. coli in various examined samples. The prevalence of E. coli was 42.5%, 27.5%, 17.5%, and 32.5% in the examined milk samples, blood specimens, nasal, and fecal swabs, respectively.

Figure 2

The distribution of E. coli serovars among various examined samples. The most prevalent E. coli serovar accompanied the respiratory infection was 086a, diarrhea: O114, fever: O111, and mastitis: O1.

Figure 3

Antimicrobial resistance pattern of the retrieved E. coli strains (n = 48). The retrieved isolates displayed high resistance to ampicillin and amoxicillin (100%), cefotaxime and ceftazidime (83.3%), amoxicillin-clavulanic acid (60.4%), and imipenem and meropenem (50%). Besides, the examined strains were highly susceptible to colistin sulfate (100%), and levofloxacin (93.8%).

Figure 4

The correlation between the tested antimicrobial agents. The intensity of colors indicates the numerical value of the correlation coefficient (r), red, and blue color refers to the negative and positive correlations, respectively.

Figure 5

The distribution of virulence-determinant and antibiotic-resistance genes among the recovered strains. The tested strains harbored the virulence-determinant genes phoA, hly, tsh, eaeA, sta, and lt with a prevalence of 100%, 50%, 45.8%, 25%, 8.4%, and 6.2%, respectively. Besides, they harbored the bla_TEM, bla_CTX, and bla_KPC resistance genes with a prevalence of 100%, 83.3%, and 50%, respectively.

Figure 6

The correlation between virulence genes and the antibiotic-resistance genes. The intensity of colors indicates the numerical value of the correlation coefficient (r), red, and blue color refers to the negative and positive correlations, respectively.

Figure 7

The heat-map illustrates the distribution of virulence genes and the antibiotic-resistance genes among the recovered E. coli serovars. The intensity of colors indicates the numerical value of the distribution.

Figure 8

The correlation between various phenotypic multidrug-resistance patterns and the antibiotic-resistance genes. The intensity of colors indicates the numerical value of the correlation coefficient (r), red, and blue color refers to the negative and positive correlations, respectively.